WorldWideScience

Sample records for alluvium

  1. Colloid-Facilitated Plutonium Transport in Saturated Alluvium

    International Nuclear Information System (INIS)

    Natural groundwater colloids have been recognized as possible agents for enhancing the subsurface transport of strongly-sorbing radionuclides. To evaluate this mechanism, packed-bed column experiments were conducted comparing the simultaneous transport of dissolved plutonium (Pu), Pu sorbed onto natural colloids, 190-nm and 500-nm diameter fluorescent CML microspheres, and tritiated water in saturated alluvium. Experiments were conducted in two columns having slightly different porosities at two flow rates, resulting in average linear velocities (vz) of 0.6 to 3.65 cm/hr in one column and 0.57 to 2.85 cm/hr in the other. In all experiments, Pu associated with natural colloids transported through alluvium essentially unretarded, while dissolved Pu was entirely retained. These results were consistent with the strong sorption of Pu to alluvium and the negligible desorption from natural colloids, observed in separate batch experiments, over time scales exceeding those of the column experiments. Breakthroughs of natural colloids preceded tritiated water in all experiments, indicating a slightly smaller effective pore volume for the colloids. The enhancement of colloids transport over tritiated water decreased with vz, implying ∼ 40% enhancement at vz = 0. The 500-nm CML microspheres were significantly attenuated in the column experiments compared to the 190-nm microspheres, which exhibited slightly more attenuation than natural colloids

  2. Research on Ground Movement Laws for Strip Mining Under Thick Alluvium

    Institute of Scientific and Technical Information of China (English)

    谭志祥; 邓喀中; 杨军

    2002-01-01

    With the discrete element method, the simulation and analysis of a series of numerical models were made. This research revealed ground movement laws for strip mining under thick alluvium and gave calculation formulae for the maximum ground subsidence and horizontal movement as a function of basement rock thickness and mining width, thus providing sound evidence for future strip mining under thick alluvium.

  3. Response of a pipeline to ground movements caused by trenching in compressible alluvium

    Science.gov (United States)

    Carder, D. R.; Taylor, M. E.; Pocock, R. G.

    Disturbance of the ground due to work on buried services, such as the renewal, replacement or construction of deep sewers, is likely to cause differential ground movements in the vicinity. This may be a factor contributing to failure in nearby service pipelines such as drainage, gas and water mains. The response of an instrumented shallow buried pipeline to ground movements caused by adjacent deep trenching in a compressible alluvium is described.

  4. Simulated ground-water flow and water quality of the Mississippi River alluvium near Burlington, Iowa, 1999

    Science.gov (United States)

    Boyd, Robert A.

    2001-01-01

    The City of Burlington, Iowa, obtains some of its public water supply by withdrawing ground water from the Mississippi River alluvium, an alluvial aquifer adjacent to the Mississippi River. The U.S. Geological Survey, in cooperation with the City of Burlington, conducted a hydrologic study of the Mississippi River alluvium near Burlington in 1999 to improve understanding of the flow system, evaluate the effects of hypothetical pumping scenarios on the flow system, and evaluate selected water-quality constituents in parts of the alluvium.

  5. Colloid-Facilitated Transport of Plutonium, Pu(+V), in Saturated Alluvium

    Science.gov (United States)

    Abdel-Fattah, A. I.; Reimus, P. W.; Ware, S.; Haga, M. H.

    2004-12-01

    Natural groundwater colloids can facilitate the subsurface transport of strongly-sorbing radionuclides, such as plutonium (Pu). To evaluate this mechanism, packed-bed column experiments were conducted, comparing the simultaneous transport of dissolved plutonium (Pu-239) of an initial oxidation state (+V), Pu sorbed onto natural colloids, 190-nm and 500-nm diameter fluorescent Carboxylate Modified Latex (CML) microspheres, and tritium, as a conservative tracer, in saturated alluvium. The experiments were conducted in two columns having slightly different porosities at two flow rates, resulting in average linear velocities, v, of 0.6 to 3.65 cm/hr in one column and 0.57 to 2.85 cm/hr in the other. In all experiments, Pu associated with natural colloids transported through alluvium essentially unretarded, while dissolved Pu was entirely retained. These results were consistent with the strong sorption of Pu to alluvium and the negligible desorption from natural colloids, observed in separate batch experiments, over time scales exceeding those of the column experiments. The breakthrough of natural colloids preceded that of tritium in all experiments, indicating a slightly smaller effective pore volume for the colloids. The enhancement of colloids' transport over tritium decreased with v, implying ~40% enhancement at v = 0. The 500-nm CML microspheres were significantly attenuated in the column experiments compared to the 190-nm microspheres, which exhibited slightly more attenuation than natural colloids.

  6. Defining Colluvium and Alluvium: An Experiment to Discuss and Consolidate Perspectives

    Science.gov (United States)

    Miller, Bradley; Juilleret, Jérôme

    2016-04-01

    Describing Earth materials with a shared terminology facilitates international collaboration because it reduces misunderstandings about the connections being made between observations and interpretations. The terms colluvium and alluvium are widely used, but their meanings vary almost as widely. Definitions for these terms can include connections to different geomorphic processes, landscape positions, or hydrology. In soil science, colluvium can be particularly influential as it is recognized in some national classification systems (e.g. France, Germany) as diagnostic material for "Colluvisols." Clarifying the meaning and diagnostic criteria of colluvium versus alluvium is especially important today because some definitions connect colluvium directly to erosion processes that are wide-spread and enhanced by anthropogenic activities. For example, the German "kolluvium" is pronounced the same as colluvium, but describes deposits at the base of hillslopes produced by water and/or tillage erosion. This contrasts with the common North American definition of colluvium describing materials transported primarily by gravity (i.e. mass movement). This poster raises awareness of the issue by illustrating the variety of published definitions for both colluvium and alluvium. Then it asks viewers to engage in the conversation by completing a survey either on paper or later online. The viewers are also invited to join the discussion on the same question, posed on the ResearchGate website (https://www.researchgate.net/post/How_do_you_define_colluvium).

  7. "Nonlinear" characteristics of the static earth pressure coefficient in thick alluvium

    Institute of Scientific and Technical Information of China (English)

    XU Zhi-wei; ZENG Kai-hua; WEI Zhou; LIU Zhi-qiang; ZHAO Xiao-dong; TIAN Qiu-hong

    2009-01-01

    Exact calculations of the static earth pressure from a thick alluvium require accurate K0 values. These calculations influence the sinking cost and the safety of the freezing method. The static earth pressure coefficient (K0) of thick and deep soil was analyzed using laboratory tests. The results show that the static earth pressure coefficient of thick and deep soils is nonlinear and different from that of superficial soils. The constant of superficial soils is usually invariant and the total stress or incremental stress definitions used in traditional geo-mechanics give the same value. The influence of load increments when calculating for superficial soil is ignored. The difference in values of K0 for thick alluvium defined by the total stress or the incremental stress methods is over 10%. The effects of the thick alluvium on K0 should be considered during the design of frozen shaft projects. Such things as the frozen shaft thickness and the excavated section height should be chosen to assure the rationality of the design and to avoid potential faults and accidents.

  8. The geochronological timing and alluvium of the tablelands in the Puli Basin, Taiwan

    Science.gov (United States)

    Tseng, Chia-Han; Lüthgens, Christopher; Tsukamoto, Sumiko; Reimann, Tony; Frechen, Manfred; Böse, Margot

    2015-04-01

    Tablelands are prominent geomorphic features in the Puli Basin in central Taiwan. Being composed of sediments, they provide clues to understand links between past climatic evolution and tectonic events resulting in the formation of the present-day landforms. To establish a geochronological framework of the tablelands, optically stimulated luminescence dating was applied to obtain burial ages of the tableland deposits. The numerical dating indicate an accumulation phase in the Late Pleistocene to Early Holocene transition. By integrating data from previous studies on topography, sediment characteristics in the study and adjacent areas, huge amounts of alluvium were deposited as alluvial fans in 5‒6 thousand years into the Puli Basin based on the results of the luminescence dating. The study area in the Taomi River catchment, an obviously longer precursor of the Taomi River, originating from west of the Yuchih Basin, transported the sediments forming the present-day southern tablelands. During the Pleistocene-Holocene transition, the climate changed to more wet and warmer conditions, so that slope processes might have changed and an increasing transport in the fluvial system was stimulated. Fluvial and fan terraces in other river catchments in Taiwan also indicate a period of increased erosion and fluvial transport at that time. After the deposition of the alluvial fan, an estimated mean incision rate of at least 15 mm/a of the Taomi River reflects local tectonic activities. Fluvial processes controlled by climatic change and accompanied by tectonic activities have created the diverse topography in the Puli Basin.

  9. Groundwater flooding vulnerability assessment in riverside alluviums of Nakdong River, South Korea

    Science.gov (United States)

    Chang, kwangsoo; Lee, Seunghyun; Kwon, Mijin; Kim, Deoggeun

    2016-04-01

    Soil wetting or inundation due to rising groundwater table can cause groundwater flooding in the riverside alluvium and also affect the scale of surface water flooding. There is possible to occur the flooding of lowland by falling the groundwater level at heavy rain and is important to evaluate the vulnerability and the prediction of groundwater problem. Three groups (safe, intermediate, and vulnerable) are classified by using groundwater flooding vulnerability index(FVI) which is calculated using groundwater level's time series measured at each monitoring well. A prediction model for the classification is developed by using a discriminant analysis based on the correlation between the original groups and physical features (topography, soil, sediment layer distribution, soil drainage, and groundwater level-related features). And we have created a groundwater flooding vulnerability GIS Map. This research results is possible to policy support of establishment of flooding providing the flooding vulnerability technique using the groundwater occurring the damage came from the fluctuation of groundwater level by the water level change of river and the effect of rainfall. Also, in conjunction with the existing flooding/drought map, it improve the accuracy of groundwater flooding/drought prediction, and it becomes possible to respond the water sources, water level down by using the evaluation system in flooding/drought.

  10. Validating Mechanistic Sorption Model Parameters and Processes for Reactive Transport in Alluvium

    Energy Technology Data Exchange (ETDEWEB)

    Zavarin, M; Roberts, S K; Rose, T P; Phinney, D L

    2002-05-02

    The laboratory batch and flow-through experiments presented in this report provide a basis for validating the mechanistic surface complexation and ion exchange model we use in our hydrologic source term (HST) simulations. Batch sorption experiments were used to examine the effect of solution composition on sorption. Flow-through experiments provided for an analysis of the transport behavior of sorbing elements and tracers which includes dispersion and fluid accessibility effects. Analysis of downstream flow-through column fluids allowed for evaluation of weakly-sorbing element transport. Secondary Ion Mass Spectrometry (SIMS) analysis of the core after completion of the flow-through experiments permitted the evaluation of transport of strongly sorbing elements. A comparison between these data and model predictions provides additional constraints to our model and improves our confidence in near-field HST model parameters. In general, cesium, strontium, samarium, europium, neptunium, and uranium behavior could be accurately predicted using our mechanistic approach but only after some adjustment was made to the model parameters. The required adjustments included a reduction in strontium affinity for smectite, an increase in cesium affinity for smectite and illite, a reduction in iron oxide and calcite reactive surface area, and a change in clinoptilolite reaction constants to reflect a more recently published set of data. In general, these adjustments are justifiable because they fall within a range consistent with our understanding of the parameter uncertainties. These modeling results suggest that the uncertainty in the sorption model parameters must be accounted for to validate the mechanistic approach. The uncertainties in predicting the sorptive behavior of U-1a and UE-5n alluvium also suggest that these uncertainties must be propagated to nearfield HST and large-scale corrective action unit (CAU) models.

  11. A novel ground surface subsidence prediction model for sub-critical mining in the geological condition of a thick alluvium layer

    Science.gov (United States)

    Chang, Zhanqiang; Wang, Jinzhuang; Chen, Mi; Ao, Zurui; Yao, Qi

    2015-06-01

    A substantial number of the coal mines in China are in the geological condition of thick alluvium layer. Under these circumstances, it does not make sense to predict ground surface subsidence and other deformations by using conventional prediction models. This paper presents a novel ground surface subsidence prediction model for sub-critical mining in the geological condition of thick alluvium layer. The geological composition and mechanical properties of thick alluvium is regarded as a random medium, as are the uniformly distributed loads on rock mass; however, the overburden of the rock mass in the bending zone is looked upon as a hard stratum controlling the ground surface subsidence. The different subsidence and displacement mechanisms for the rock mass and the thick alluvium layer are respectively considered and described in this model, which indicates satisfactory performances in a practical prediction case.

  12. Geostatistical Analysis of Spatial Variability of Mineral Abundance and Kd in Frenchman Flat, NTS, Alluvium

    Energy Technology Data Exchange (ETDEWEB)

    Carle, S F; Zavarin, M; Pawloski, G A

    2002-11-01

    LLNL hydrologic source term modeling at the Cambric site (Pawloski et al., 2000) showed that retardation of radionuclide transport is sensitive to the distribution and amount of radionuclide sorbing minerals. While all mineralogic information available near the Cambric site was used in these early simulations (11 mineral abundance analyses from UE-5n and 9 from RNM-l), these older data sets were qualitative in nature, with detection limits too high to accurately measure many of the important radionuclide sorbing minerals (e.g. iron oxide). Also, the sparse nature of the mineral abundance data permitted only a hypothetical description of the spatial distribution of radionuclide sorbing minerals. Yet, the modeling results predicted that the spatial distribution of sorbing minerals would strongly affect radionuclide transport. Clearly, additional data are needed to improve understanding of mineral abundances and their spatial distributions if model predictions in Frenchman Flat are to be defensible. This report evaluates new high-resolution quantitative X-Ray Diffraction (XRD) data on mineral distributions and their abundances from core samples recently collected from drill hole ER-5-4. The total of 94 samples from ER-5-4 were collected at various spacings to enable evaluation of spatial variability at a variety of spatial scales as small as 0.3 meters and up to hundreds of meters. Additional XRD analyses obtained from drillholes UE-Sn, ER-5-3, and U-11g-1 are used to augment evaluation of vertical spatial variability and permit some evaluation of lateral spatial variability. A total of 163 samples are evaluated. The overall goal of this study is to understand and characterize the spatial variation of sorbing minerals in Frenchman Flat alluvium using geostatistical techniques, with consideration for the potential impact on reactive transport of radionuclides. To achieve this goal requires an effort to ensure that plausible geostatistical models are used to

  13. Field measurements of the linear and nonlinear shear moduli of cemented alluvium using dynamically loaded surface footings

    Science.gov (United States)

    Park, Kwangsoo

    In this dissertation, a research effort aimed at development and implementation of a direct field test method to evaluate the linear and nonlinear shear modulus of soil is presented. The field method utilizes a surface footing that is dynamically loaded horizontally. The test procedure involves applying static and dynamic loads to the surface footing and measuring the soil response beneath the loaded area using embedded geophones. A wide range in dynamic loads under a constant static load permits measurements of linear and nonlinear shear wave propagation from which shear moduli and associated shearing strains are evaluated. Shear wave velocities in the linear and nonlinear strain ranges are calculated from time delays in waveforms monitored by geophone pairs. Shear moduli are then obtained using the shear wave velocities and the mass density of a soil. Shear strains are determined using particle displacements calculated from particle velocities measured at the geophones by assuming a linear variation between geophone pairs. The field test method was validated by conducting an initial field experiment at sandy site in Austin, Texas. Then, field experiments were performed on cemented alluvium, a complex, hard-to-sample material. Three separate locations at Yucca Mountain, Nevada were tested. The tests successfully measured: (1) the effect of confining pressure on shear and compression moduli in the linear strain range and (2) the effect of strain on shear moduli at various states of stress in the field. The field measurements were first compared with empirical relationships for uncemented gravel. This comparison showed that the alluvium was clearly cemented. The field measurements were then compared to other independent measurements including laboratory resonant column tests and field seismic tests using the spectral-analysis-of-surface-waves method. The results from the field tests were generally in good agreement with the other independent test results, indicating

  14. Determination of Abutment Pressure in Coal Mines with Extremely Thick Alluvium Stratum: A Typical Kind of Rockburst Mines in China

    Science.gov (United States)

    Zhu, Sitao; Feng, Yu; Jiang, Fuxing

    2016-05-01

    This paper investigates the abutment pressure distribution in coal mines with extremely thick alluvium stratum (ETAS), which is a typical kind of mines encountering frequent intense rockbursts in China. This occurs due to poor understanding to abutment pressure distribution pattern and the consequent inappropriate mine design. In this study, a theoretical computational model of abutment pressure for ETAS longwall panels is proposed based on the analysis of load transfer mechanisms of key stratum (KS) and ETAS. The model was applied to determine the abutment pressure distribution of LW2302S in Xinjulong Coal Mine; the results of stress and microseismic monitoring verified the rationality of this model. The calculated abutment pressure of LW2302S was also used in the terminal mining line design of LW2301N for rockburst prevention, successfully protecting the main roadway from the adverse influence of the abutment pressure.

  15. Chemical weathering of a soil chronosequence on granitoid alluvium: II. Mineralogic and isotopic constraints on the behavior of strontium

    Science.gov (United States)

    Bullen, T.; White, A.; Blum, A.; Harden, J.; Schulz, M.

    1997-01-01

    The use of strontium isotopes to evaluate mineral weathering and identify sources of base cations in catchment waters requires an understanding of the behavior of Sr in the soil environment as a function of time. Our approach is to model the temporal evolution of 87Sr/86Sr of the cation exchange pool in a soil chronosequence developed on alluvium derived from central Sierra Nevada granitoids during the past 3 Ma. With increasing soil age, 87Sr/86Sr of ammonium-acetate extractable Sr initially decreases from values typical of K-feldspar to those of plagioclase and hornblende and then remains constant, even though plagioclase and hornblende are absent from the soils after approximately 1 Ma of weathering. The temporal variation of 87Sr/86Sr of exchangeable Sr is modeled by progressively equilibrating Sr derived from mineral weathering and atmospheric deposition with Sr on exchange sites as waters infiltrate a soil column. Observed decreases in quartz-normalized modal abundances of plagioclase, hornblende, and K-feldspar with time, and the distinct 87Sr/86Sr values of these minerals can be used to calculate Sr flux from weathering reactions. Hydrobiotites in the soils have nearly constant modal abundances, chemistry, and 87Sr/86Sr over the chronosequence and provide negligible Sr input to weathering solutions. The model requires time and soil horizon-dependent changes in the amount of exchangeable Sr and the efficiency of Sr exchange, as well as a biologic cycling term. The model predicts that exchangeable Sr initially has 87Sr/86Sr identical to that of K-feldspar, and thus could be dominated by Sr leached from K-feldspar following deposition of the alluvium. The maximum value of 87Sr/86Sr observed in dilute stream waters associated with granitoids of the Yosemite region is likewise similar to that of the K-feldspars, suggesting that K-feldspar and not biotite may be the dominant source of radiogenic Sr in the streams. This study reveals that, when attempting to use

  16. Anomalous gold, antimony, arsenic, and tungsten in ground water and alluvium around disseminated gold deposits along the Getchell Trend, Humboldt County, Nevada

    Science.gov (United States)

    Grimes, D.J.; Ficklin, W.H.; Meier, A.L.; McHugh, J.B.

    1995-01-01

    Ground-water, alluvium, and bedrock samples were collected from drill holes near the Chimney Creek, Preble, Summer Camp, and Rabbit Creek disseminated gold deposits in northern Nevada. Results of chemical analyses of drill-hole water samples show the presence of hydromorphic dispersion anomalies of Au, As, Sb, and W in the local ground-water systems associated with these deposits. In addition, analysis of sequential dissolution and extraction solutions of drill cuttings of alluvium and bedrock indicate geochemical anomalies of gold and ore-related metals in the overburden at depths corresponding to the location of the present-day water table. This relationship suggests that water-rock reactions around these buried deposits are active. -from Authors

  17. Application of Mat Traps to Determine the Present Speed of Accumulation of Alluvium at the Ryazan Area in the Middle Reaches of the Oka River

    Directory of Open Access Journals (Sweden)

    Krivtsov V.A.

    2015-12-01

    Full Text Available Investigation of the processes of channel sedimentation in riverbeds of lowland rivers has important fundamental and practical importance. In the economic development of river valleys a lot of attention is paid to the dynamics of the major reliefforming processes within the floodplain. A typical example showing the pattern of forming landforms and type of floodplain processes is deposition and redeposition of riverine sediment. In the future sedimentation of alluvium in areas of riverine floodplain makes the growth rate of natural levees, islands and shoals. For the average flow of the Oka river the pace of modern dynamics of accumulation of alluvium in the riverine areas is clarified. For the first time in this area the method of mat traps is applied. Rubber and coconut fiber were selected as the main materials for the traps. Specific features of the application methods and the difficulties encountered in its application were defined. The authors obtained the data about thickness of the layer of sediment accumulation of river flood of 2015, the results of particle size analysis of alluvial material with traps. The main patterns of distribution of fractions of alluvium and the pace of accumulation of various forms of riverine floodplain accumulation were identified. Tested methodology has proven its effectiveness and was found promising for use in the future in this region.

  18. SIMULATION OF FLUID FLOW AND ENERGY TRANSPORT PROCESSES ASSOCIATED WITH HIGH-LEVEL RADIOACTIVE WASTE DISPOSAL IN UNSATURATED ALLUVIUM.

    Science.gov (United States)

    Pollock, David W.

    1986-01-01

    Many parts of the Great Basin have thick zones of unsaturated alluvium which might be suitable for disposing of high-level radioactive wastes. A mathematical model accounting for the coupled transport of energy, water (vapor and liquid), and dry air was used to analyze one-dimensional, vertical transport above and below an areally extensive repository. Numerical simulations were conducted for a hypothetical repository containing spent nuclear fuel and located 100 m below land surface. Initial steady state downward water fluxes of zero (hydrostatic) and 0. 0003 m yr** minus **1 were considered in an attempt to bracket the likely range in natural water flux. Predicted temperatures within the repository peaked after approximately 50 years and declined slowly thereafter in response to the decreasing intensity of the radioactive heat source. The extent of the dry zone was strongly controlled by the mobility of liquid water near the repository under natural conditions. In the case of initial hydrostatic conditions, the dry zone extended approximately 10 m above and 15 m below the repository. For the case of a natural flux of 0. 0003 m yr** minus **1 the relative permeability of water near the repository was initially more than 30 times the value under hydrostatic conditions, consequently the dry zone extended only about 2 m above and 5 m below the repository. In both cases a significant perturbation in liquid saturation levels persisted for several hundred years. This analysis illustrates the extreme sensitivity of model predictions to initial conditions and parameters, such as relative permeability and moisture characteristic curves.

  19. Characteristics of soils developed from alluvium and their potential for cocoa plant development in East Kolaka Regency, Southeast Sulawesi

    Directory of Open Access Journals (Sweden)

    E. Yatno

    2016-04-01

    Full Text Available Cocoa is one of plantation commodities that is quite important for the national economy. Land management for the development of this plant should pay attention to the characteristics of the soil. Three soil profiles formed from alluvium parent material in East Kolaka Regency were investigated to determine the mineralogical, physical, and chemical soil properties, as well as the potential of the land for the development of cocoa plant. The results showed that the mineral composition of the sand fraction was dominated by quartz, while the clay mineral fraction was composed of kaolinite, hydrate halloysite, interstratified of illite-vermiculite and smectite. The soils were characterized by poor drainage, low bulk density (0.78 to 0.95 g / cm3, moderate available water pores (10-15%, slow to fast permeability (0.10 to 14.05 cm / h, silty clay loam to silty clay texture of top soil, acidic soil reaction (pH 4.62 to 5.47, high organic C content (3.86 to 4.60% in the top soil and very low organic C content (<0.65% in the lower layer, moderate to high available P (14-38 mg / kg in the A horizon and very low to moderate (1-18 mg / kg in horizon B, moderate to high P2O5 (30-71 mg / 100g in horizon A and extremely low (1-11 mg / 100g in horizon B, very low to moderate K2O (3-28 mg / 100g , moderate to high exchangeable Ca (9.32 to 13.92 cmolc / kg in the upper and lower (0.70 to 5.04 cmolc / kg in the bottom layer, high exchangeable Mg content (2.83 to 8.95 cmolc / kg, high soil CEC (34.18 to 38.28 cmolc / kg in the upper layer and low to moderate (7.87 to 20.39 cmolc / kg in the bottom layer, moderate to high base saturation (44-68%, and very low to moderate Al saturation (0-17%. At the family level, the soil was classified as Fluvaquentic Endoaquepts (EK 1 profile and Typic Endoaquepts (EK 2 and EK 3 profiles, finely loamy, mix, acid, isohypertermik. The land was marginally suitable (S3 for cocoa plant with the contraints of impeded drainage, acid soil

  20. Analysis on probability of water inrush and quicksand in different mining sequences under an unconsolidated alluvium aquifer by fluid-solid coupling theory

    Institute of Scientific and Technical Information of China (English)

    CHEN Lu-wang; QIN Yuan; GUI He-rong; ZHANG Shi-lei

    2012-01-01

    To study the behavior of overlying strata and the likelihood of water inrush and quicksand with different mining sequences under an unconsolidated alluvium aquifer,a numerical model based on the fluid-solid coupling theory was constructed by FLAC3D.Simulation results revealed that the mining sequences had a significant influence on the seepage,displacement and failure characteristics of the overlying strata.In this kind of geological and hydrogeological conditions,the workface close to the outcrop of coal seam easily suffers from water inrush and quicksand during mining.In the simulation resuits,the plastic zone,vertical displacement and pore water pressure in the overlying strata of the workface decrease more or less using the upward mining sequence than using the downward mining sequence.Therefore,the application of the upward mining sequence in the process of mining is preferential to prevent water inrush and quicksand.

  1. An evaluation of Mesodon and other larger terrestrial gastropod shells for dating late Holocene and historic alluvium in the Midwestern USA

    Science.gov (United States)

    Rakovan, Monica T.; Rech, Jason A.; Pigati, Jeffery S.; Nekola, Jeffery C.; Wiles, Gregory C.

    2013-01-01

    Understanding the history of stream erosion and changes in channel morphology is important for managing and restoring unstable streams. One of the significant challenges in this type of research is establishing accurate dating of late Holocene and historic alluvium. Here we evaluate the potential of using 14C dating and amino acid racemization (AAR) to date large terrestrial gastropod shells that are often preserved within alluvial sediments. Many terrestrial gastropods incorporate old carbon from limestone or other carbonate rocks into their shells and therefore are unsuitable for radiocarbon dating. Recent studies, however, have shown that some taxa avoid this ‘limestone problem’ and can yield reliable 14C ages. In this study, we measured the 14C activity of specimens for the genera Mesodon, Ventridens, and Allogona collected live and from alluvial sequences dated independently by dendrochronology, 14C dating of wood, and/or 137Cs analyses. Mesodon zaletus contained old carbon in similar concentrations (up to ~ 30%) found in previous studies of other large taxa and should be avoided for 14C dating when possible. In contrast, shells of Ventridens ligera and Allogona profunda showed minimal limestone effects and therefore may be suitable for dating late Holocene alluvium. These results highlight the importance of taxonomic identification of gastropod taxa prior to their use for 14C dating and demonstrate that shell fragments that are not identifiable should be avoided. We also measured d/l ratios (n = 17) of aspartic and glutamic acid from eight different taxa of terrestrial gastropods recovered from four late Holocene and historic stratigraphic sequences. Average d/l ratios of aspartic and glutamic acid from historic sediments < 300 years old are lower in shells from younger stratigraphic units, indicating that AAR can be used to differentiate between multiple historic stratigraphic units.

  2. Application of Surface Geophysical Methods, With Emphasis on Magnetic Resonance Soundings, to Characterize the Hydrostratigraphy of the Brazos River Alluvium Aquifer, College Station, Texas, July 2006 - A Pilot Study

    Science.gov (United States)

    Shah, Sachin D.; Kress, Wade H.; Legchenko, Anatoly

    2007-01-01

    The U.S. Geological Survey, in cooperation with the Texas Water Development Board, used surface geophysical methods at the Texas A&M University Brazos River Hydrologic Field Research Site near College Station, Texas, in a pilot study, to characterize the hydrostratigraphic properties of the Brazos River alluvium aquifer and determine the effectiveness of the methods to aid in generating an improved ground-water availability model. Three non-invasive surface geophysical methods were used to characterize the electrical stratigraphy and hydraulic properties and to interpret the hydrostratigraphy of the Brazos River alluvium aquifer. Two methods, time-domain electromagnetic (TDEM) soundings and two-dimensional direct-current (2D-DC) resistivity imaging, were used to define the lateral and vertical extent of the Ships clay, the alluvium of the Brazos River alluvium aquifer, and the underlying Yegua Formation. Magnetic resonance sounding (MRS), a recently developed geophysical method, was used to derive estimates of the hydrologic properties including percentage water content and hydraulic conductivity. Results from the geophysics study demonstrated the usefulness of combined TDEM, 2D-DC resistivity, and MRS methods to reduce the need for additional boreholes in areas with data gaps and to provide more accurate information for ground-water availability models. Stratigraphically, the principal finding of this study is the relation between electrical resistivity and the depth and thickness of the subsurface hydrostratigraphic units at the site. TDEM data defined a three-layer electrical stratigraphy corresponding to a conductor-resistor-conductor that represents the hydrostratigraphic units - the Ships clay, the alluvium of the Brazos River alluvium aquifer, and the Yegua Formation. Sharp electrical boundaries occur at about 4 to 6 and 20 to 22 meters below land surface based on the TDEM data and define the geometry of the more resistive Brazos River alluvium aquifer

  3. Elements of structure and productivity of clone I-214 (Populus×euramericana (Dode Guinier plantations on the river Sava alluvium

    Directory of Open Access Journals (Sweden)

    Andrašev Siniša

    2010-01-01

    Full Text Available Two experimental plantations of Euramerican poplar (Populus×euramericana (Dode Guinier - clone I-214 were researched on the river Sava alluvium in Srem. Three sample plots were established in each of the plantations, aged 31 years. The soil type was humofluvisol (alluvial semigley, planting space 6×6 m. The plantations were established with 278 rooted cuttings per hectare, and the number of trees at the age of 31 accounted for 46.5-60.6%. The constructed height curves, mean stand height (hg and upper (hg20% heights show that the study plantations were established on different site classes, which was significantly reflected on other plantation growth elements and productivity. However, there was no significant effect of site class on the variability (sd and cv and shape of diameter structure (α3 and α4. The constructed models of diameter structure for each site class (by Weibull function differ by location parameter (a, and do not differ by parameter of scale (b and shape (c. The tree and plantation growth elements show a high production potential of the clone I-214 which indicates that, on optimal soils and with the provided technological measures in the stage of nursery production and in the stage of plantation establishment, clone I-214 presents the good base for high production effects.

  4. Behaviour of concrete faced rock dams on granular alluvium foundations[General Conference]; Comportement des barrages en enrochement avec masque amont en beton de ciment fondes sur des alluvions granulaires

    Energy Technology Data Exchange (ETDEWEB)

    Massiera, M.; Vautour, J.; Coulibaly, Y.; Szostak-Chrzanowski, A. [Moncton Univ., NB (Canada). Dept. of Civil Engineering; Hammamji, Y. [Hydro-Quebec, Montreal, PQ (Canada). Hydraulic and Geotechnical Engineering Div

    2006-07-01

    Two sets of deformation analyses for concrete face rockfill dams (CFRDs) were presented. CFRDs deform during their construction and also under the effect of water load during reservoir filling when the rockfill deforms under the water pressure. The concrete face follows the rockfill deformation. In this study, 2 typical cross sections and 4 heights of CFRDs were examined. The first set of analyses focused on slope stability once the reservoir was filled. The second set of analyses focused on stress-strain analyses in order to calculate the upstream face displacements and the internal movements that occur in the rockfill embankment and its foundation during the construction phase as well as the reservoir filling phase. It was concluded that it is possible to construct CFRDs on compact to dense granular alluvium deposits having a thickness of less than 60 metres, as long as the granular alluvium foundation is compacted to a depth of 30 metres.

  5. Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 24. Seismic Refraction Tomography for Volume Analysis of Saturated Alluvium in the Straight Creek Drainage and Its Confluence With Red River, Taos County, New Mexico

    Science.gov (United States)

    Powers, Michael H.; Burton, Bethany L.

    2007-01-01

    As part of a research effort directed by the New Mexico Environment Department to determine pre-mining water quality of the Red River at a molybdenum mining site in northern New Mexico, we used seismic refraction tomography to create subsurface compressional-wave velocity images along six lines that crossed the Straight Creek drainage and three that crossed the valley of Red River. Field work was performed in June 2002 (lines 1-4) and September 2003 (lines 5-9). We interpreted the images to determine depths to the water table and to the top of bedrock. Depths to water and bedrock in boreholes near the lines correlate well with our interpretations based on seismic data. In general, the images suggest that the alluvium in this area has a trapezoidal cross section. Using a U.S. Geological Survey digital elevation model grid of surface elevations of this region and the interpreted elevations to water table and bedrock obtained from the seismic data, we generated new models of the shape of the buried bedrock surface and the water table through surface interpolation and extrapolation. Then, using elevation differences between the two grids, we calculated volumes of dry and wet alluvium in the two drainages. The Red River alluvium is about 51 percent saturated, whereas the much smaller volume of alluvium in the tributary Straight Creek is only about 18 percent saturated. When combined with average ground-water velocity values, the information we present can be used to determine discharge of Straight Creek into Red River relative to the total discharge of Red River moving past Straight Creek. This information will contribute to more accurate models of ground-water flow, which are needed to determine the pre-mining water quality in the Red River.

  6. Total System Performance Assessment-License Application Design Selection (LADS) Phase 1 Analysis of Surface Modification Consisting of Addition of Alluvium (Feature 23a)

    Energy Technology Data Exchange (ETDEWEB)

    N. Erb

    1999-06-11

    than the present levels. Conceptually, the topographic surface above the repository foot-print would be re-contoured to make it more suitable for placement of unconsolidated materials (e.g., alluvium). Figure 1 shows the region of the surface modification in relation to the location of the repository foot-print. The surface contours in this region after modification are shown in the plot presented in Figure 2. Basically, the surface modification would be accomplished by applying cuts to the ridges slopes on the east flank of Yucca Mountain to produce a relatively uniform slope of about 10%. The alluvium would be covered with rock fragments (to imitate the desert pavement) to reduce erosion. This report documents the modeling assumptions and performance analysis conducted to estimate the long-term performance for Feature 23a. The performance measure for this evaluation is dose-rate. Results are presented that compare the dose-rate time histories for the new design feature to those of the TSPA-VA base case calculation (CRWMS M&O 1998a).

  7. Behaviour of concrete face rockfill dams resting on moraine or granular alluvium deposits; Comportement des barrages en enrochement avec masque amont en beton de ciment reposant sur des depots de moraine ou sur des alluvions granulaires

    Energy Technology Data Exchange (ETDEWEB)

    Massiera, M.; Vautour, J.; Szostak-Chrzanowski, A. [Moncton Univ., NB (Canada). Dept. of Civil Engineering

    2008-07-01

    Dam safety depends on proper design, construction, and monitoring of actual behaviour during construction and during the operation of the structure. This study examined whether it is possible to construct a concrete face rockfill dam (CFRD) on dense moraine deposits of up to 140 metres in thickness. CFRDs are known to deform during construction and under the influence of water load as the reservoir is filled. The study was performed for dams of 75, 100, 125 and 150 metres in height with 2 different type sections, namely upstream and downstream slopes. The movement of the upstream face and internal displacements in each of the dams was simulated during construction as well as during reservoir filling. Two sets of deformation analyses for CFRDs were presented. First, slope stability was analyzed at the end of the reservoir filling. Next, the stress-strain was analysed in order to calculate the upstream face displacements and the internal movements that occur in the rockfill embankment and the till foundation during the construction phase as well as the reservoir filling phase. It was concluded that it is possible to erect CFRDs on dense to very dense till deposits while maintaining safety coefficients of slopes that are compatible with the structural integrity of the concrete face. The CFRDs built on compact to dense granular alluvium deposits should have a thickness of less than 60 metres and the granular alluvium foundation should be compacted to a depth of 30 metres. 17 refs., 5 tabs., 9 figs.

  8. Study on Features of Surface Dynamic Movement and Deformation Caused by Coal Mining Under Thick Alluvium%厚松散层煤层开采地表动态移动变形特征研究

    Institute of Scientific and Technical Information of China (English)

    李德海; 许国胜; 余华中

    2014-01-01

    In order to protect of buildings and control the ground subsidence in the area of covering thick alluvium,based on the measured data of surface movement and deformation above No. 11011 working face of Zhaogu No. 1 Coal Mine,dynamic changes of surface subsidence curve,surface subsidence maximum velocity,surface movement and deformation duration and lagging distance of maximum subsidence velocity were analyzed with mining under thick alluvium.The results indicated that rapid changes in value of surface subsidence appeared, maximum of subsidence velocity was 24.5 mm/d,movement was intense and range of surface subsidence increased obviously.The surface subsidence coefficient expected was more than one in case of full extraction.In the surface movement duration,active phase accounted for 53. 4% the total time,while 91.3% the total subsidence occurred in this period,and decline phase of surface subsidence lasted for a long time,but had a litter subsidence.The working surface of maximum subsidence velocity lag distance was 182 m.The above resluts showed that with the coal mining under thick alluvium,the surface had a several features,for example,subsidence was sensitive to coal caving effect,surface subsidence velocity and coefficient was large,and surface movement was serious,and decline phase of surface subsidence lasted for a long time.%为控制地表沉陷保护地表建筑物,以赵固一矿11011工作面的地表移动变形的实测数据为基础,分析研究了厚松散层条件开采下,地表下沉曲线的动态变化、地表最大下沉速度、地表移动变形持续时间及最大下沉速度滞后情况。结果表明:由于上覆厚松散层土体结构松散、几乎无承载能力,地表下沉量变化较大,地表下沉速度较大,最大值为24.5 mm/d、下沉剧烈且地表下沉的范围增加较明显,在充分采动的情况下,预计其地表下沉系数大于1。在地表移动持续时间中,

  9. 薄冲积层下开采地表动态移动规律与特征%Dynamic laws and characteristics of surface movement induced by mining under thin alluvium

    Institute of Scientific and Technical Information of China (English)

    唐君; 王金安; 王磊

    2014-01-01

    High-voltage transit lines, gas and petroleum pipelines, riverbeds and other facilities located in mining disturbed zones are extremely sensitive to surface dynamic movement. Based on the case of coal mining under Jinsha river in Gansu province, in-site surface movement monitoring is carried out;and the dynamic law of surface subsidence of fully mechanized top coal caving mining under the thin alluvium is obtained. The study shows that the surface subsidence experiences a very short initial period and a longer active period of movement. The active period of surface movement appears in the range from 110 m in front of the working face to 400 m back of working face, which lasts 185 days and results in 90.7%of the total surface subsidence. The severe period of surface subsidence occurs at 50 m to 150 m in the rear of working face;but the severer movement time is relatively short about 60 days. Based on the sinking curves of the measuring point displaying S-shaped distribution, and the sinking rate curves that are similar to normal distribution, the dynamic model of surface subsidence and sinking rate are established with respect to the mining time and advancing rate. The trajectories of ground measuring points are captured showing the back and forth moving characteristics. The fractures on the surface induced by mining under thin alluvium intend to develop parallel to the mining direction. With the working face advancing, the time and space features demonstrate that the surface fractures move forward and the concentration areas expand to the outside of the mining area.%位于采煤影响区的高压线、输气输油管道、河道等设施对地表动态移动极为敏感。以甘肃某煤矿在金沙河下开采为背景,通过现场地表移动监测,获得薄冲积层条件下综放开采地表动态移动变形规律。研究表明:薄冲积层下综放开采地表具有下沉移动起始期很短、活跃期较长等特点。地表移动

  10. Analysis and prediction of vertical shaft freezing pressure in deep alluvium based on RBF fuzzy neural network model%基于RBF模糊神经网络模型的深厚冲积层立井冻结压力分析与预测

    Institute of Scientific and Technical Information of China (English)

    姚亚锋; 程桦; 荣传新; 黎明镜; 蔡海兵; 宋健

    2016-01-01

    The field measurement of varied monitoring levels about the shaft freezing pressure in Dingji mine has shown that the freezing pressure changes with time and circumstance. It is easily influ-enced by many factors, such as strata depth, geotechnical moisture content, average freezing wall thick-ness and mean temperature, and that it has obvious uncertainty. The degree of uncertainty has been characterized by the variation coefficient, laying a foundation for optimizing the traditional RBF neural network and introducing variation coefficient of freezing pressure to fuzzy central value and weight value learning strategy to establish prediction model of shaft freezing pressure in deep alluvium. With variables of strata depth, geotechnical moisture content, average freezing wall thickness and mean tem-perature as the input information, the model has been used to distinguish clay strata and calcareous clay strata in training and learning with sample data from thirty three monitoring levels in seven shafts of Huainan and Huaibei areas, and finally has made an engineering prediction for the shaft freezing pres-sure in Kouzidong mine. The results have shown that the field measurement has well fitted with the pre-diction;the efficient and precise model algorithm has provided reliable basis for analysis and prediction of vertical shaft freezing pressure in deep alluvium of Huainan and Huaibei areas.%针对丁集矿井壁冻结压力进行不同监测水平的现场实测,发现冻结压力随时间和环境而变化,受层位深度、岩土含水率、冻结壁平均厚度和平均温度等因素的影响,具有明显的不确定性,以变异系数表征其不确定程度。在此基础上优化传统的RBF神经网络,把变异系数引入模糊中心值和权值学习策略中,建立深厚冲积层井壁冻结压力预测模型。该模型以层位深度、含水率、冻结壁平均厚度和平均温度为输入信息量,区分黏土层与钙质黏

  11. Litology and possibilities of comprehensive using modern alluvium Dnieper

    Directory of Open Access Journals (Sweden)

    Ivanchenko V. V.

    2015-09-01

    Full Text Available Studied mineralogy of bottom sediments of the Lower Dnieper. The identified minerals zirconium, rare earths (monazite, titanium, grenades, etc., is finding gold, silver and diamonds. In addition to typical detrital grains tumors installed component authigenic sediment - pyrite, marcasite, carbonates, goethite. The observed constant presence of particles of sludge, slag, refractory, metallurgical graphite, spinel, glass and ore balls - indicators of anthropogenic pollution. Search interest with gold, zircon, ilmenite, rutile, monazite, diamond. When passing extraction can be used light fraction minerals: quartz, kaolinite and other clay minerals and mushlevyy detritus and limestone.

  12. Craton-derived alluvium as a major sediment source in the Himalayan Foreland Basin of India

    DEFF Research Database (Denmark)

    Sinha, R.; Kettanah, Y.; Gibling, M.R.;

    2009-01-01

    of the Yamuna. This gray cratonic sediment was probably deposited in part by the Chambal River, which transports high-grade metamorphic minerals from the Banded Gneiss Complex of the Aravalli belt. Cratonic sediment appears to interfinger with Himalayan detritus farther north below the Ganga-Yamuna Interfluve....... With its headwaters in the tectonically unstable Indus-Ganga watershed area, the Yamuna River may have occupied its present course late in the Quaternary, and if so, cratonic rivers may have provided the basin's axial drainage for prolonged periods. The penetration of Himalayan sediment to the distal......Within the Himalayan Foreland Basin, the axial Yamuna River with Himalayan headwaters lies along the northern margin of the Indian Craton, giving the impression that cratonic rivers have contributed little to the basin compared with Himalayan drainages. However, the Betwa, Chambal, and other rivers...

  13. Groundwater pollution with heavy metals in the Ibar alluvium near Raška (Serbia)

    OpenAIRE

    Miladinović Branko; Papić Petar; Mandić Marina

    2012-01-01

    As a result of the operation of an ore flotation facility at Donja Rudnica near Raška, Serbia, during the period from 1972 to 2002, flotation tailings and wastewater of highly complex chemical compositions were deposited in the alluvial plain of the Ibar River. Due to the excellent groundwater flow characteristics of the alluvial formations underlying the tailings dump, the groundwater and soil over an extended area were continually polluted. High concentrations of heavy metals (Fe = 7....

  14. Groundwater pollution with heavy metals in the Ibar alluvium near Raška (Serbia

    Directory of Open Access Journals (Sweden)

    Miladinović Branko

    2012-01-01

    Full Text Available As a result of the operation of an ore flotation facility at Donja Rudnica near Raška, Serbia, during the period from 1972 to 2002, flotation tailings and wastewater of highly complex chemical compositions were deposited in the alluvial plain of the Ibar River. Due to the excellent groundwater flow characteristics of the alluvial formations underlying the tailings dump, the groundwater and soil over an extended area were continually polluted. High concentrations of heavy metals (Fe = 7.38 mg/L. Zn = 4.04 mg/L, Pb = 2.17 mg/L in the soil and concentrations of sulfate as high as 3709 mg/L, and pH levels of 4.2 in the groundwater have been recorded at some locations. This paper draws attention to the potential risk this site poses for the conservation of biodiversity over the extended area.

  15. Influence of Underground Mining on Ground Surface and Railway Bridge Under Thick Alluvium

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Patterns of ground movement and pore water pressure variation are obtained through a case study using a finite element method. With the progress of excavation, ground subsidence, ground inclination and horizontal displacement accelerates. Along the striking direction, a subsidence basin is formed on the ground surface induced by underground mining. The maximum subsidence is around 5.41m. The ratio of ground subsidence to the thickness of the coal seam is 1.08. The maximum inclination is 11.5 mm/m. The maximum horizontal displacement is 2.15 mm/m. At the time the coal has been excavated, the maximum pore water pressure reaches 25 kPa. In order to improve protection of structures located over the area with underground mining, the variation of additional stresses of a railway bridge induced by ground surface deformation is analyzed. The main effect of underground mining on the railway bridge is the tensile stress and the maximum value reaches as high as 4.29 MPa, which is greater than the concrete tensile strength.

  16. Anthropogenic impact on sediment composition and geochemistry in vertical overbank profiles of river alluvium from Belgium and Luxembourg

    OpenAIRE

    Swennen, R.; Van der Sluys, J.

    2002-01-01

    The geochemical study of alluvial sediments allows to reconstruct pollution through time. Geochemical and sedimentological variations recorded in 40 vertical overbank sediment profiles from Belgium and Luxembourg can be classified in three dominant pattern types: . type 1 profiles with dominantly non-anthropogenically influenced geochemical distribution patterns. These profiles are devoid of anthropogenic particles such as charcoal, plastic, brick and slag fragments, with the exception, in so...

  17. “ Sedimentology and geochemistry of recent alluvium of the wadi Beht mean (Furrow south western Rif, Morocco: dynamics of implementation and hydrological and climatic meanings ”

    Directory of Open Access Journals (Sweden)

    Ahmed LAABIDI

    2016-05-01

    Full Text Available The watershed of the river Beht is located northwest of Morocco and occupies the southwestern part of the Sebou basin. This study focuses on the sedimentological and geochemical analysis of current alluvial floodplain and meandering filling abandoned Middle Beht. The results revealed that the sediments exhibit an alkaline pH, low levels of carbonates, low values of the electrical conductivity and relatively high contents of organic matter mostly in the finest sediment. Deposits are organized in grano-decreasing repetitive elementary sequences much more expressed and fines in meandering filling abandoned deposits, which function as ephemeral lakes, as in those of the floodplain. They are the expression of the sedimentological variation of hydrodynamics related to the succession of flood-related flood recession cycles themselves with climate change. They are set up on the often rocky deposits texture background meandering channels and bars. The sequence of these basic sequences, sandy-silty clay at the base and silty-sandy clay on top, gives larger sequences grano-decreasing.

  18. Cave levels as proxies for measuring post-orogenic uplift: Evidence from cosmogenic dating of alluvium-filled caves in the French Pyrenees

    Science.gov (United States)

    Calvet, M.; Gunnell, Y.; Braucher, R.; Hez, G.; Bourlès, D.; Guillou, V.; Delmas, M.

    2015-10-01

    The rates and chronology of valley incision in mountain ranges have been studied in various parts of the globe, but the causes of river incision are often blurred because tectonic, climatic, and sea level-related forcing signals are difficult to distinguish from one another. The Têt River limestone gorge in the Eastern Pyrenees, which displays multiple cave levels containing datable alluvial deposits, provides an opportunity for clarifying this debate. Horizontal epiphreatic passages in limestone can be used as substitutes for fluvial terraces because they correspond to former valley floors and, therefore, also record the position of former local base levels. In the Têt canyon, the passages are filled with quartz-rich sand and gravel sequences that can be dated by 26Al/10Be burial dating. The canyon has cut into a Middle Miocene pediment system-now forming a raised plateau at 1250-1500 m-and displays nine cave levels over a vertical height of 1 km. One alluvial fill sequence in a cave at + 270 m above datum (i.e., the local river bed) yielded a weighted mean age of 5.14 ± 0.41 Ma; another, situated at + 110 m above datum, yielded weighted mean ages of 2.23 ± 0.230 Ma and 1.20 ± 0.286 Ma. The data convert to a mean incision rate of ~ 52 m·Ma- 1 since the beginning of the Pliocene, and involved an acceleration to 92 m·Ma- 1 during the Quaternary. Pre-burial catchment denudation rates range from 35 to 7 m·Ma- 1, and these also doubled during the early Quaternary. It is concluded that: (i) valley incision into the Miocene pediment has been occurring since 5, probably 10 Ma; (ii) there is no evidence of a Messinian canyon in the Villefranche gorge, strongly suggesting through various additional indicators that interference of the Messinian Salinity Crisis with the canyon incision history was minimal; (iii) valley deepening was not a steady process, and recorded periods of stability around 1-2 Ma and perhaps 6-5 Ma; and (iv) the terraced network of epiphreatic cave levels is primarily explained by tectonic uplift. It follows that the elevated erosion surfaces of the Pyrenees, such as the Miocene pediment directly situated above the canyon edge, were not shaped at high elevations, e.g., by 'altiplanation'; they formed, instead, close to base level and were uplifted in successive stages by tectonic processes. The study emphasizes the more general proposition that tectonic signals (as opposed to climatic or eustatic) in valley-incision chronologies are best singled out at locations situated among the outer ranges of mountain belts, i.e., in canyons such as the Têt, that respond immediately to base level changes relative to the adjacent foreland. In the inner ranges, fluvial incision is more likely to be affected by the interference of climatic factors (e.g., glaciers), or to be delayed by bedrock impediments to upstream-propagating knickpoints.

  19. Chemical weathering rates of a soil chronosequence on granitic alluvium: I. Quantification of mineralogical and surface area changes and calculation of primary silicate reaction rates

    Science.gov (United States)

    White, A.F.; Blum, A.E.; Schulz, M.S.; Bullen, T.D.; Harden, J.W.; Peterson, M.L.

    1996-01-01

    Mineral weathering rates are determined for a series of soils ranging in age from 0.2-3000 Ky developed on alluvial terraces near Merced in the Central Valley of California. Mineralogical and elemental abundances exhibit time-dependent trends documenting the chemical evolution of granitic sand to residual kaolinite and quartz. Mineral losses with time occur in the order: hornblende > plagioclase > K-feldspar. Maximum volume decreases of >50% occur in the older soils. BET surface areas of the bulk soils increase with age, as do specific surface areas of aluminosilicate mineral fractions such as plagioclase, which increases from 0.4-1.5 m2 g-1 over 600 Ky. Quartz surface areas are lower and change less with time (0.11-0.23 m2 g-1). BET surface areas correspond to increasing external surface roughness (?? = 10-600) and relatively constant internal surface area (??? 1.3 m2 g-1). SEM observations confirm both surface pitting and development of internal porosity. A numerical model describes aluminosilicate dissolution rates as a function of changes in residual mineral abundance, grain size distributions, and mineral surface areas with time. A simple geometric treatment, assuming spherical grains and no surface roughness, predicts average dissolution rates (plagioclase, 10-17.4; K-feldspar, 10-17.8; and hornblende, 10-17.5 mol cm-1 s-1) that are constant with time and comparable to previous estimates of soil weathering. Average rates, based on BET surface area measurements and variable surface roughnesses, are much slower (plagioclase, 10-19.9; K-feldspar, 10-20.5; and hornblende 10-20.1 mol cm-2 s-1). Rates for individual soil horizons decrease by a factor of 101.5 over 3000 Ky indicating that the surface reactivities of minerals decrease as the physical surface areas increase. Rate constants based on BET estimates for the Merced soils are factors of 103-104 slower than reported experimental dissolution rates determined from freshly prepared silicates with low surface roughness (?? soils is limited without consideration of variable surface areas and processes that control the evolution of surface reactivity with time.

  20. DS926 Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system in Florida and parts of Georgia, Alabama, and South Carolina - Alluvium_major_streams_buffer

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part...

  1. Earthquake Risk - MO 2013 Liquefaction Potential St. Louis Area (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Soil liquefaction potential was determined using existing surficial materials and floodplain alluvium maps. Alluvium deposits and artificial deposits are generally...

  2. Earthquake Risk - MO 2013 Liquefaction Potential (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Soil liquefaction potential was determined using existing geologic and alluvium maps. Quaternary, Tertiary, and Cretaceous-age sediments, and alluvium deposits are...

  3. PAN-AFRICAN CENTRAL AFRICAN FOLD BELT, WITH EMPHASIS ON BEDROCKS AND HEAVY MINERAL ANALYSIS OF RIVER ALLUVIUM IN THE NORTHERN CAMEROON%中非造山带:喀麦隆北部地质构造与河流沉积物重矿物分析

    Institute of Scientific and Technical Information of China (English)

    叶浩; Merlain Houketchang Bouyo; 赵越; 刘健

    2014-01-01

    简要叙述冈瓦纳超大陆聚合过程和中非造山带泛非期地质构造过程,剖析了西冈瓦纳喀麦隆北部和乍得西南地区岩石构造单元及其形成的构造背景并对喀麦隆北部河流冲积物进行了重矿物分析.分析结果表明重矿物可能来自近源基岩,为西喀麦隆地体(Western Cameroon Domain)内的雷博巴(Rey Bouba)绿岩带和马约科比(Mayo Kebbi)弧岩浆岩带;重矿物中的自然金可能主要来自雷博巴绿岩带.分析结果为该地区砂金矿开采提供了一定的指示.

  4. Diseño de obras de control de aluviones basada en simulación de procesos hidrológicos torrenciales en cuencas de la Patagonia Design of alluvium control structures based on flash flood simulation in the Patagonia basins

    Directory of Open Access Journals (Sweden)

    Ana Cecilia Dufilho

    2001-05-01

    Full Text Available Fenómenos climáticos torrenciales que producen aluviones y grandes movimientos de sedimentos (bajo distintas formas son muy frecuentes en la Patagonia Argentina. Los estudios para el diseño de obras de control se realizan en general, a través de fórmulas empíricas sin verificar su aptitud a las condiciones patagónicas. En el presente trabajo se utilizan modelos matemáticos sencillos para la simulación hidrológica de crecidas en cuencas con escasa información hidrometeorológica y nula instrumentación. Esta metodología requiere estimar la lluvia de diseño asumiendo un nivel de riesgo, evaluar la eficiencia de distintos planes de control mediante simulaciones de distintas alternativas de obras y seleccionar aquella de menor costo.Climatic processes leading to flash flood and large sediment movements (under different forms are very frequent in Patagonia, Argentina. Often, projects of small reservoirs and levees are based on empirical formulations without a verification of their aptitude to the local conditions. In the present work, simple flood mathematical models are used for hydrological simulation in basins with scarce precipitation and flood data. This methodology requires estimation of the design storm associated with a risk level. It allows simulation and evaluation of alternative control projects, facilitating the selection of the least cost control scheme.

  5. Clay minerals and Sr-Nd isotopes of the sediments along the western margin of India and their implication for sediment provenance

    Digital Repository Service at National Institute of Oceanography (India)

    Kessarkar, P.M.; Rao, V.P.; Ahmad, S.M.; Babu, G.A.

    - gion is occupied by Recent alluvium and the Warkala beds (ferruginised sand stones with inter- calated clays) of Tertiary age. Extensive laterisation of the parent rocks is a characteristic feature in western India. Bauxite- and laterite...

  6. A maritime archaeological exploration along the Narmada estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A.S.; Sundaresh

    Books. Sonakia, A. 1984. The skull cap of early man and associated mammalian fauna from Narmada Valley alluvium, Hoshangabad area, Madhya Pradesh, India, Records of the Geological Survey of India 113:159-172. Sonakia, A. and S. Biswas 1998...

  7. Alluvial Aquifer

    Data.gov (United States)

    Kansas Data Access and Support Center — This coverage shows the extents of the alluvial aquifers in Kansas. The alluvial aquifers consist of unconsolidated Quaternary alluvium and contiguous terrace...

  8. Subsidence characterization and modeling for engineered facilities in Arizona, USA

    Science.gov (United States)

    Rucker, M. L.; Fergason, K. C.; Panda, B. B.

    2015-11-01

    Several engineered facilities located on deep alluvial basins in southern Arizona, including flood retention structures (FRS) and a coal ash disposal facility, have been impacted by up to as much as 1.8 m of differential land subsidence and associated earth fissuring. Compressible basin alluvium depths are as deep as about 300 m, and historic groundwater level declines due to pumping range from 60 to more than 100 m at these facilities. Addressing earth fissure-inducing ground strain has required alluvium modulus characterization to support finite element modeling. The authors have developed Percolation Theory-based methodologies to use effective stress and generalized geo-material types to estimate alluvium modulus as a function of alluvium lithology, depth and groundwater level. Alluvial material modulus behavior may be characterized as high modulus gravel-dominated, low modulus sand-dominated, or very low modulus fines-dominated (silts and clays) alluvium. Applied at specific aquifer stress points, such as significant pumping wells, this parameter characterization and quantification facilitates subsidence magnitude modeling at its' sources. Modeled subsidence is then propagated over time across the basin from the source(s) using a time delay exponential decay function similar to the soil mechanics consolidation coefficient, only applied laterally. This approach has expanded subsidence modeling capabilities on scales of engineered facilities of less than 2 to more than 15 km.

  9. Application of a mixing cell model to describe contaminant transport - An example of appropriate technology

    International Nuclear Information System (INIS)

    The Uranium Mill Tailings Remedial Action (UMTRA) Project is undertaking remedial actions at designated inactive uranium mill sites. The mill tailings lie within an alluvial floodplain adjacent to the Colorado River. Mancos Shale with hydraulic conductivity of 5x10/sup -4/ to 2x10/sup -7/ cm/sec lies below four to more than six meters (13.1 to 19.7 feet) of alluvium. The mill site is surrounded by industry and residences of the city of Grand Junction. Ground water in the alluvium flows generally parallel to the Colorado River with the Colorado River adjacent to the mill site being an effluent stream during the fall and winter and an influent stream during the spring snowmelt runoff. In the vicinity of the tailings, the saturated thickness of the alluvium ranges from less than 3.05, meters (10 feet) to more than 6.10 meters (20 feet). Portions of the tailings are below the water table

  10. 77 FR 27804 - Entergy Operations, Inc.; Grand Gulf Nuclear Station, Unit 1

    Science.gov (United States)

    2012-05-11

    ... River Alluvium aquifer. This is a conservative estimate of aquifer capacity impact, as aquifer recharge... service water system for GGNS is treated with sodium hypochlorite and biocides to control the pH in the... to the auxiliary cooling tower, additional sodium hypochlorite injection will be needed to...

  11. Electromagnetic survey (TEM method) in Teradomari and examination of resistivity structure to be based on near surface information; Niigataken Teradomarimachi ni okeru denji tansa kekka (TEM ho) no doshitsu joho ni yoru kento

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, H.; Mitsuhata, Y.; Matsuo, K.; Tanaka, H. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center; Wada, K. [Mitsui Mineral Development Engineering Co. Ltd., Tokyo (Japan)

    1996-10-01

    TEM method was applied to estimate soil structure from resistivity change of underground water saturated stratum featured by slow S wave and fast P wave over 1500m/s. Vertical magnetic field was measured by underlaying a transmission loop of 60m{times}60m around a measuring point in Teradomari, Niigata prefecture, and by installing a magnetic sensor at the measuring point. From comparison of a soil profile with the resistivity profile obtained by TEM data, the former well consisted with the latter. The surface low resistivity stratum corresponded to alluvium from comparison of it with soil and logging data. This alluvium base with fast P wave over 1500m/s satisfied the condition of optimum blasting depth because of a saturated stratum in the surface base. The resistivity structure was related to a saturated stratum. Sand bed was thick at the interface between alluvium low ground and hill area, and from the analytical result, the depth of sand bed showing high resistivity was more shallow than that of the alluvium base, pointing out necessary notice in interpretation. Resistivity survey is promising as simple method for optimum blasting depth. 4 refs., 6 figs., 1 tab.

  12. Jiamusi Leading to the Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    SANJIANG Plain in eastern Heilongjiang Province was formed from the alluvium of the winding and rolling Heilong, Songhua, and Wusuli rivers. Located in the hinterland of the fertile Sanjiang Plain, Jiamusi faces Russia’s far east region on its opposite bank, and a border measuring 438 kilometers.

  13. Hydrology of coal-lease areas near Durango, Colorado

    Science.gov (United States)

    Brooks, Tom

    1985-01-01

    The U.S. Bureau of Land Management leases Federal lands and minerals for coal mining near Durango, Colorado. This report addresses the hydrologic suitability of those lands for coal leasing; the report describes the general hydrology of the Durango area and, more specifically, the hydrology of the Stollsteimer Creek study area 32 miles east of the Durango and the Hay Gulch study area, 12 miles southwest of Durango. The most productive aquifers in the Durango study area are Quaternary alluvium and the tertiary Animas Formation. Water wells completed in alluvium typically yield 5 to 20 gallons/min; wells completed is the Animas Formation yield as much as 50 gallons/min. Water quality in these aquifers is variable, but it generally is suitable for domestic use. The coal-bearing Cretaceous Fruitland and Menefee Formations are mined by surface methods at the Chimney Rock Mine in the Stollsteimer Creek study area and by underground methods at the National King Coal Mine in the Hay Gulch study area. Effects of surface mining in the Stollsteimer Creek area are: (1) Dewatering of an alluvial aquifer; and (2) Local degradation of alluvium water quality by spoil-pile effluent. Effects of underground mining in the Hay Gulch area are: (1) Introduction of water with greater dissolved-solids concentrations into the upper Hay Gulch alluvium from mine runoff; (2) Subsidence fracturing which could dewater streams and the alluvial aquifer. (USGS)

  14. Examples of transient sounding from groundwater exploration in sedimentary aquifers

    Science.gov (United States)

    Fitterman, D.V.

    1987-01-01

    Examples of the use of transient electromagnetic soundings for three groundwater exploration problems in sedimentary aquifers are given. The examples include: 1) estimating depths to water table and bedrock in an alluvium-filled basin, 2) mapping a confined freshwater aquifer in bedrock sediments, and 3) locating a freshwater/saltwater interface in a glacial-outwash aquifer. -from Author

  15. LAMBERSART "LES CONQUERANTS" (DEULE VALLEY, NORTH OF FRANCE) : A WEICHSELIAN EARLY-PLENIGLACIAL SLOPE-BOTTOM VALLEY TRANSITION

    NARCIS (Netherlands)

    Deschodt, Laurent; Munaut, Andre-Valentin; Limondin-Lozouet, Nicole; Boulen, Muriel

    2008-01-01

    The Lambersart "les Conquerants" trench sequence is made of a Shelly loam topped by coarse alluviums. The whole is covered by several meters thick pleniglacial loess. The palynological and malacological data shows that this Shelly loam deposit occured during Early Glacial, in cold and moist conditio

  16. International Uranium Resources Evaluation Project (IUREP) national favourability studies: Democratic Kampuchea (Cambodia)

    International Nuclear Information System (INIS)

    The potential for uranium deposits appears to be poor in Cambodia. It is largely alluvium. Uranium may occur in discordant deposits in metamorphics and intrusives in the Cardamon and Elephant Hills in the south, and in placers of U/TH minerals in the delta or banks of the Mekong River. The potential is in category 1 (less than 1000 tonnes U ). (author)

  17. Ground motion estimation in Delhi from postulated regional and local earthquakes

    Science.gov (United States)

    Mittal, Himanshu; Kumar, Ashok; Kamal

    2013-04-01

    Ground motions are estimated at 55 sites in Delhi, the capital of India from four postulated earthquakes (three regional M w = 7.5, 8.0, and 8.5 and one local). The procedure consists of (1) synthesis of ground motion at a hard reference site (NDI) and (2) estimation of ground motion at other sites in the city via known transfer functions and application of the random vibration theory. This work provides a more extensive coverage than earlier studies (e.g., Singh et al., Bull Seism Soc Am 92:555-569, 2002; Bansal et al., J Seismol 13:89-105, 2009). The Indian code response spectra corresponding to Delhi (zone IV) are found to be conservative at hard soil sites for all postulated earthquakes but found to be deficient for M w = 8.0 and 8.5 earthquakes at soft soil sites. Spectral acceleration maps at four different natural periods are strongly influenced by the shallow geological and soil conditions. Three pockets of high acceleration values are seen. These pockets seem to coincide with the contacts of (a) Aravalli quartzite and recent Yamuna alluvium (towards the East), (b) Aravalli quartzite and older quaternary alluvium (towards the South), and (c) older quaternary alluvium and recent Yamuna alluvium (towards the North).

  18. Quality of water from freshwater aquifers and principal well fields in the Memphis Area, Tennessee

    Science.gov (United States)

    Brahana, J.V.; Parks, W.S.; Gaydos, M.W.

    1987-01-01

    Water from the freshwater aquifers in the Memphis area is suitable for most uses. Freshwater aquifers are the alluvium and fluvial (terrace) deposits of Quaternary age, the Memphis Sand and Fort Pillow Sand of Tertiary age, and the Ripley Formation and McNairy Sand of Cretaceous age. About 180 million gallons/day (mgd) of freshwater are withdrawn from the Memphis Sand, primarily for municipal and industrial use; the Memphis Sand is the principal aquifer supplying the City of Memphis. The alluvium provides water for irrigation and some industrial uses, and the fluvial deposits provide water for domestic use in rural areas. The Fort Pillow Sand supplies water for some municipal and industrial uses. The Ripley-McNairy aquifer is not used as a source of water. Water from the alluvium, fluvial deposits, and Memphis Sand is a calcium bicarbonate type, and water from the Fort Pillow Sand and Ripley-McNairy aquifer is a sodium bicarbonate type. Dissolved solids concentrations are low in the Memphis Sand, with a median value of 83 mg/L, and are high in the Ripley-McNairy aquifer with a value of about 1,000 mg/L. Water is very soft in the Fort Pillow Sand with a median hardness value of 9 mg/L as CaCO3 and is very hard in the alluvium with a median value of 285 mg/L. Iron concentrations are low in the fluvial deposits with a median value of 50 micrograms/L and are high in the alluvium with a median value of 5,200 micrograms/L. Temperature of the water generally increases with depth, ranging from 16.0 C in the alluvium and fluvial deposits to about 32.0 C in the Ripley-McNairy aquifer. Water from the Memphis Sand at Memphis Light, Gas and Water Division well fields has very low mineralization. Median values are 79 mg/L dissolved solids concentrations, 56 mg/L alkalinity as CaCO3, 46 mg/L hardness as CaCO3, 4 mg/L chloride, 3.5 mg/L sulfate, and 600 micrograms/L iron. (Author 's abstract)

  19. Geologic map of the Vancouver and Orchards quadrangles and parts of the Portland and Mount Tabor quadrangles, Clark County, Washington, and Multnomah County, Oregon

    Science.gov (United States)

    O'Connor, Jim E.; Cannon, Charles M.; Mangano, Joseph F.; Evarts, Russell C.

    2016-06-03

    IntroductionThis is a 1:24,000-scale geologic map of the Vancouver and Orchards quadrangles and parts of the Portland and Mount Tabor quadrangles in the States of Washington and Oregon. The map area is within the Portland Basin and includes most of the city of Vancouver, Washington; parts of Clark County, Washington; and a small part of northwestern Multnomah County, Oregon. The Columbia River flows through the southern part of the map area, generally forming the southern limit of mapping. Mapped Quaternary geologic units include late Pleistocene cataclysmic flood deposits, eolian deposits, and alluvium of the Columbia River and its tributaries. Older deposits include Miocene to Pleistocene alluvium from an ancestral Columbia River. Regional geologic structures are not exposed in the map area but are inferred from nearby mapping.

  20. Pollen taphonomy in a canyon stream

    Science.gov (United States)

    Fall, Patricia L.

    1987-11-01

    Surface soil samples from the forested Chuska Mountains to the arid steppe of the Chinle Valley, Northeastern Arizona, show close correlation between modern pollen rain and vegetation. In contrast, modern alluvium is dominated by Pinus pollen throughout the canyon; it reflects neither the surrounding floodplain nor plateau vegetation. Pollen in surface soils is deposited by wind; pollen grains in alluvium are deposited by a stream as sedimentary particles. Clay-size particles correlate significantly with Pinus, Quercus, and Populus pollen. These pollen types settle, as clay does, in slack water. Chenopodiaceae- Amaranthus, Artemisia, other Tubuliflorae, and indeterminate pollen types correlate with sand-size particles, and are deposited by more turbulent water. Fluctuating pollen frequencies in alluvial deposits are related to sedimentology and do not reflect the local or regional vegetation where the sediments were deposited. Alluvial pollen is unreliable for reconstruction of paleoenvironments.

  1. MUNSELL COLOR ANALYSIS OF LANDSAT COLOR-RATIO-COMPOSITE IMAGES OF LIMONITIC AREAS IN SOUTHWEST NEW MEXICO.

    Science.gov (United States)

    Kruse, Fred A.

    1984-01-01

    Green areas on Landsat 4/5 - 4/6 - 6/7 (red - blue - green) color-ratio-composite (CRC) images represent limonite on the ground. Color variation on such images was analyzed to determine the causes of the color differences within and between the green areas. Digital transformation of the CRC data into the modified cylindrical Munsell color coordinates - hue, value, and saturation - was used to correlate image color characteristics with properties of surficial materials. The amount of limonite visible to the sensor is the primary cause of color differences in green areas on the CRCs. Vegetation density is a secondary cause of color variation of green areas on Landsat CRC images. Digital color analysis of Landsat CRC images can be used to map unknown areas. Color variations of green pixels allows discrimination among limonitic bedrock, nonlimonitic bedrock, nonlimonitic alluvium, and limonitic alluvium.

  2. Structural geology of the Hawthorne and Tonopah quadrangles, Nevada

    Science.gov (United States)

    Ferguson, H.G.; Muller, S.W.

    1949-01-01

    The area lies in west-central Nevada near the western border of the Basin and Range province. Paleozoic and Mesozoic rocks the chief subject of this report occur in isolated mountain ranges separated by stretches of Tertiary and Quaternary volcanic rocks, lacustrine deposits and alluvium. The report is concerned principally with the geology of the pre-Tertiary rocks and attempt is made to unravel the complex diastrophisni that occurred in the area during the Jurassic. 

  3. Long-term improvement of agricultural vegetation by floodwater spreading in the Gareh Bygone Plain, Iran. In the pursuit of human security, is artificial recharge of groundwater more lucrative than selling oil?

    Science.gov (United States)

    Mesbah, Sayyed Hamid; Mohammadnia, Mehrdad; Kowsar, Sayyed Ahang

    2016-03-01

    In southern Iran's Gareh Bygone Plain, water-supply qanats in four mixed farming communities were desiccated by over-pumping of illegal dug wells throughout the area. Emergency situations developed, resulting in city-ward migration. Since 1983, 193 million m3 of water has been supplied to those communities by floodwater spreading (FWS) to facilitate spate irrigation of sandy rangeland (2,034 ha) and artificial recharge of groundwater (ARG), of which 76 % has recharged the aquifer. This resulted in a reverse migration of the population. The irrigated area in the 2010-2011 growing season increased 13.2 fold when compared to the pre-FWS period, and year-round forage for about 700 sheep has been provided since 1991. The ARG is a logical alternative to building large dams in Iran; 420,000 km2 of coarse-grained alluvium provides capacity to store 5,000 km3 of water, representing more than ten times the annual precipitation of the whole country. As the equivalent cost for building dams to accommodate that volume is estimated at US12.5 × 1012, the potential value of the alluvium may be realized. ARG on the recharge areas of 33,000 of the desiccated qanats eventually could rejuvenate them. As agricultural commodities absorb 19 % of the monetary value of Iran's imports, and ARG activities could supply the water to produce them, alluvium is even more valuable than oil, which provides foreign exchange. More importantly, ARG on 140,000 km2 of the alluvium could strengthen the capacity to adapt to droughts and reduce the number and impact of water-related emergency situations.

  4. Hydrogeochemical characterization of an evaporite karst area affected by sinkholes (Ebro Valley, NE Spain)

    OpenAIRE

    Acero, P.; F. Gutiérrez; Galve, J.P.; Auqué, L.F.; Carbonel, D.; Gimeno, M. J.; Gómez, J. B.; Asta, M.P.; Yechieli, Y.

    2013-01-01

    The main processes controlling the hydrochemistry of an alluvium-covered evaporite karst area with high sinkhole risk (Ebro Valley, NE Spain) are examined by means of multivariate analyses (Principal Component Analysis and Hierarchical Cluster Analysis), ion correlations and geochemical speciation-solubility calculations. The hydrogeochemistry of the studied system seems to be governed by the interaction between the groundwater from the salt-bearing evaporitic karst aquifer and from the overl...

  5. Valorisation des boues de lavage de gravière dans le domaine du stockage d'eau potable, d'eau chaude et de la rétention de substances polluantes

    OpenAIRE

    De Los Cobos, Gabriel

    1994-01-01

    The present study on the recovery of gravel washing muds is placed in the context of geology applied to engineering and environment, which is a field of research done at the Laboratory of Geology (GEOLEP) of the Swiss Federal Institute of Technology in Lausanne (EPFL). Washing muds from alluvium or crushed rock constitute an industrial waste product whose utilization, for the time being, is very limited and whose disposal is an environmental problem. The recovery of this by-product can be env...

  6. Valley-fill alluviation during the Little Ice Age (ca. A.D. 1400-1880), Paria River basin and southern Colorado Plateau, United States

    Science.gov (United States)

    Hereford, R.

    2002-01-01

    Valley-fill alluvium deposited from ca. A.D. 1400 to 1880 is widespread in tributaries of the Paria River and is largely coincident with the Little Ice Age epoch of global climate variability. Previous work showed that alluvium of this age is a mappable stratigraphic unit in many of the larger alluvial valleys of the southern Colorado Plateau. The alluvium is bounded by two disconformities resulting from prehistoric and historic arroyo cutting at ca. A.D. 1200-1400 and 1860-1910, respectively. The fill forms a terrace in the axial valleys of major through-flowing streams. This terrace and underlying deposits are continuous and interfinger with sediment in numerous small tributary valleys that head at the base of hillslopes of sparsely vegetated, weakly consolidated bedrock, suggesting that eroded bedrock was an important source of alluvium along with in-channel and other sources. Paleoclimatic and high-resolution paleoflood studies indicate that valley-fill alluviation occured during a long-term decrease in the frequency of large, destructive floods. Aggradation of the valleys ended about A.D. 1880, if not two decades earlier, with the beginning of historic arroyo cutting. This shift from deposition to valley entrenchment near the close of the Little Ice Age generally coincided with the beginning of an episode of the largest floods in the preceding 400-500 yr, which was probably caused by an increased recurrence and intensity of flood-producing El Nin??o events beginning at ca. A.D. 1870.

  7. Geophysical Survey and Detailed Geologic Mapping of an Eroded Stratovolcano's Central Intrusive Complex, Summer Coon, Co.

    Science.gov (United States)

    Harp, A.

    2015-12-01

    Eroded volcanoes expose plumbing systems that provide important information on intrusive geometries, magma propagation directions, and the effects of host rock types and heterogeneities. Summer Coon Volcano, CO, is an Oligocene stratovolcano where erosion has removed much of the original edifice, revealing the intrusive stocks of the central intrusive complex (CIC). Surrounding the CIC are hundreds of radial dikes ranging from basaltic to rhyolitic in composition. Published geologic maps indicate most radial dikes do not connect to the intrusive stocks, supporting published theories that most did not emanate from the central intrusions. However, much of the area surrounding the CIC is covered by alluvium, suggesting that the lack of connection might be an artifact of exposure. We completed a ground magnetic survey and detailed geological mapping to determine if the dikes continue beneath the alluvium and into the intrusive stocks. Linear magnetic anomalies indicate four NW-SE trending rhyodacite dikes continue beneath the alluvium for up to 250 m, and mapping indicates that at least two of the rhyodacite dikes do extend into the CIC. Shorter linear anomalies are attributed to seven NW-SE trending basaltic dikes ~100-500-m-long which are sparsely exposed in the alluvium. Mapping shows that three rhyodacite dikes extend into the CIC and to within 200 m of their possible source, an 800-m-wide granodiorite stock. Additionally, three rhyolitic dikes extend to within several meters of a 200×500-m-wide tuff breccia zone of similar composition, likely their source. In summary, magnetic data and detailed mapping indicate that radial dikes do extend into the central intrusive complex in contrast to some model predictions.

  8. Summary of lithologic logging of new and existing boreholes at Yucca Mountain, Nevada, March 1994 to June 1994

    International Nuclear Information System (INIS)

    This report summarizes lithologic logging of core from boreholes at Yucca Mountain, Nevada, conducted from March 1994 to June 1994. Units encountered during logging include Quaternary-Tertiary alluvium and colluvium, Tertiary Rainier Mesa Tuff, all units in the Tertiary Paintbrush Group, and Tertiary Calico Hills Formation. Logging results are presented in a table of contact depths for core from unsaturated zone neutron (UZN) boreholes and graphic lithologic logs for core from north ramp geology (NRG) boreholes

  9. Genesis and continuity of quaternary sand and gravel in glacigenic sediment at a proposed low-level radioactive waste disposal site in east-central Illinois

    Science.gov (United States)

    Troost, K.G.; Curry, B. Brandon

    1991-01-01

    The Illinois Department of Nuclear Safety has characterized the Martinsville Alternative Site (MAS) for a proposed low-level radioactive waste disposal facility. The MAS is located in east-central Illinois approximately 1.6 km (1 mi) north of the city of Martinsville. Geologic investigation of the 5.5-km2 (1380-acre) site revealed a sequence of chiefly Illinoian glacigenic sediments from 6 to 60 m (20-200 ft) thick overlying two major bedrock valleys carved in Pennsylvanian strata. Relatively permeable buried units include basal, preglacial alluvium; a complex of intraglacial and subglacial sediment; englacial deposits; and supraglacial fluvial deposits. Postglacial alluvium underlies stream valleys on and adjacent to the site. In most areas, the buried sand units are confined by low-permeability till, lacustrine sediment, colluvium, and loess. The distribution and thickness of the most extensive and continuous buried sand units have been modified considerably by subglacial erosion, and their distributions have been influenced by the buried bedrock valleys. The most continuous of the various sand units were deposited as preglacial and postglacial alluvium and are the uppermost and lowermost stratigraphic units at the alternative site. Sand units that were deposited in englacial or ice-marginal environments are less continuous. Aquifer pumping tests, potentiometric head data, and groundwater geochemistry analyses indicate minimal interaction of groundwater across localized interconnections of the permeable units. ?? 1991 Springer-Verlag New York Inc.

  10. Site Characterization Data from the U3ax/bl Exploratory Boreholes at the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Bechtel Nevada; U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office

    2005-08-01

    This report provides qualitative analyses and preliminary interpretations of hydrogeologic data obtained from two 45-degree, slanted exploratory boreholes drilled within the Area 3 Radioactive Waste Management Site (RWMS) at the Nevada Test Site. Borehole UE-3bl-D1 was drilled beneath the U3ax/bl mixed waste disposal unit, and Borehole UE-3bl-U1 was drilled in undisturbed alluvium adjacent to the disposal unit. The U3ax/bl disposal unit is located within two conjoined subsidence craters, U3ax and U3bl, which were created by underground nuclear testing. Data from these boreholes were collected to support site characterization activities for the U3ax/bl disposal unit and the entire Area 3 RWMS. Site characterization at disposal units within the Area 3 RWMS must address the possibility that subsidence craters and associated disturbed alluvium of the chimneys beneath the craters might serve as pathways for contaminant migration. The two boreholes were drilled and sampled to compare hydrogeologic properties of alluvium below the waste disposal unit with those of adjacent undisturbed alluvium. Whether Borehole UE-3bl-D1 actually penetrated the chimney of the U3bl crater is uncertain. Analyses of core samples showed little difference in hydrogeologic properties between the two boreholes. Important findings of this study include the following: No hazardous or radioactive constituents of waste disposal concern were found in the samples obtained from either borehole. No significant differences in physical and hydrogeologic properties between boreholes is evident, and no evidence of significant trends with depth for any of these properties was observed. The values observed are typical of sandy materials. The alluvium is dry, with volumetric water content ranging from 5.6 to 16.2 percent. Both boreholes exhibit a slight increase in water content with depth, the only such trend observed. Water potential measurements on core samples from both boreholes show a large positive

  11. Saturated Zone In-Situ Testing

    Energy Technology Data Exchange (ETDEWEB)

    P. W. Reimus; M. J. Umari

    2003-12-23

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that have been conducted to test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain. The test interpretations provide estimates of flow and transport parameters that are used in the development of parameter distributions for Total System Performance Assessment (TSPA) calculations. These parameter distributions are documented in the revisions to the SZ flow model report (BSC 2003 [ 162649]), the SZ transport model report (BSC 2003 [ 162419]), the SZ colloid transport report (BSC 2003 [162729]), and the SZ transport model abstraction report (BSC 2003 [1648701]). Specifically, this scientific analysis report provides the following information that contributes to the assessment of the capability of the SZ to serve as a barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvium Testing Complex (ATC), which is located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, and

  12. Application of uphole data from petroleum seismic surveys to groundwater investigations, Abu Dhabi (United Arab Emirates)

    Science.gov (United States)

    Woodward, D.; Menges, C.M.

    1991-01-01

    Velocity data from uphole surveys were used to map the water table and the contact at the base dune sand/top alluvium as part of a joint National Drilling Company-United States Geological Survey Ground Water Research Project in the Emirate of Abu Dhabi. During 1981-1983, a reconnaissance seismic survey was conducted for petroleum exploration in the eastern region of Abu Dhabi. Approximately 2800 kilometers of seismic data, consisting of 92 lines, were acquired in the 2500 km2 concession area near Al Ain. Uphole surveys were conducted about 2 km apart along each seismic line, and were used to calculate weathering corrections required to further process in the seismic data. Approximately 1300 uphole surveys were completed in the concession area between March 1981 and June 1983. Reinterpretation of the velocity profiles derived from the uphole surveys provided data for determining the following subsurface layers, listed in descending order: (1) a surficial, unconsolidated weathering layer with a velocity from 300 to 450 m/s; (2) surficial dune sand, from 750 to 900 m/s; (3) unsaturated, unconsolidated alluvium, from 1000 to 1300 m/s; and (4) saturated, unconsolidated alluvium, from 1900 to 2200 m/s. Two interfaces-the water table and the base dune sand/top alluvium - were identified and mapped from boundaries between these velocity layers. Although the regional water table can fluctuate naturally as much as 3 m per year in this area and the water-table determinations from the uphole data span a 27-month period, an extremely consistent and interpretable water-table map was derived from the uphole data throughout the entire concession area. In the northern part of the area, unconfined groundwater moves northward and northwestward toward the Arabian Gulf; and in the central and southern parts of the area, groundwater moves westward away from the Oman Mountains. In the extreme southern area east of Jabal Hafit, groundwater moves southward into Oman. The map of the base

  13. Geohydrology and water utilization in the Willcox Basin, Graham and Cochise Counties, Arizona

    Science.gov (United States)

    Brown, S.G.; Schumann, Herbert H.

    1969-01-01

    The Willcox basin is an area of interior drainage in the northern part of Sulphur Springs Valley, Cochise and Graham Counties, Ariz. The basin comprises about 1,500 square miles, of which the valley floor occupies about 950 square miles. The basin probably formed during middle and late Tertiary time, when the area was subjected to large-scale faulting accompanied by the uplift of the mountain ranges that presently border it. During and after faulting, large quantities of alluvium were deposited in the closed basin. The rocks in the basin are divided into two broad groups--the rocks of the mountain blocks, of Precambrian through Tertiary age, and the rocks of the basin, of Tertiary and Quaternary age. The mountain blocks consist of igneous, metamorphic, and sedimentary rocks; the water-bearing characteristics of these rocks depend primarily on their degree of weathering and fracturing. Even in areas where these rocks are fractured and jointed, only small amounts of water have been developed. The rocks of the basin consist of moderately consolidated alluvium, poorly consolidated alluvium, and unconsolidated alluvium. The water-bearing characteristics of the moderately and poorly consolidated alluvium are not well known. The unconsolidated alluvium underlies most of the valley floor and consists of two facies, stream deposits and lake beds associated with the old playa. The lenticular sand and gravel layers interbedded in silt- and clay-size material of the unconsolidated alluvium constitute the principal aquifer in the basin. The other aquifers, which yield less water, consist of beds of poorly to moderately consolidated sand- and gravel-size material; these beds occur in both the poorly consolidated and moderately consolidated alluvium. In the Stewart area the median specific capacity of wells per 100 feet of saturated unconsolidated alluvium was 20 gallons per minute, and in the Kansas Settlement area the specific capacity of wells penetrating the poorly and

  14. COMPLETION REPORT FOR WELL CLUSTER ER-5-3

    Energy Technology Data Exchange (ETDEWEB)

    BECHTEL NEVADA

    2005-12-01

    Well Cluster ER-5-3 was drilled for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. This cluster of 3 wells was drilled in 2000 and 2001 as part of a hydrogeologic investigation program in Frenchman Flat. The first borehole in the cluster, Well ER-5-3, was drilled in February and March 2000. A 47.0-centimeter surface hole was drilled and cased off to the depth of 374.8 meters. The hole diameter was decreased to 31.1 centimeters for drilling to a total depth of 794.3 meters within welded ash-flow tuff. A piezometer string with 1 slotted interval was installed in the annulus of the surface casing, open to the saturated alluvium. A completion string with 2 slotted intervals was installed in the main hole, open to saturated alluvium and to the welded tuff aquifer. A second piezometer string with 1 slotted interval open to the welded-tuff aquifer was installed outside the completion string. Well ER-5-3 No.2 was drilled about 30 meters west of the first borehole in March 2000, and was recompleted in March 2001. A 66.0-centimeter hole was drilled and cased off to the depth of 613.8 meters. The hole diameter was decreased to 44.5 centimeters and the borehole was drilled and cased off to the depth of 849.0 meters. The hole diameter was decreased once more to 31.1 centimeters for drilling to a total depth of 1,732.2 meters in dolomite. A completion string open to the dolomite (lower carbonate aquifer) was installed. Well ER-5-3 No.3 was drilled approximately 30 meters north of the first 2 boreholes in February 2001. A 66.0-centimeter hole was drilled and cased off to the depth of 36.6 meters, then the main 25.1-centimeter-diameter hole was drilled to a total depth of 548.6 meters in alluvium. A slotted stainless-steel tubing string was installed in the saturated alluvium. A preliminary composite, static water level was measured at

  15. Geoarchaeological investigations at the Winger site: A Late Paleoindian bison bonebed in Southwestern Kansas, U.S.A

    Science.gov (United States)

    Mandel, R.D.; Hofman, J.L.

    2003-01-01

    The Winger site is a deeply buried Late Paleoindian bison bonebed in a playa basin on the High Plains of midcontinental North America. The site is one of few stratified, Late Paleoindian bison kills recorded in the region. The bonebed is exposed in the bank of an intermittent stream that cut into the edge of the playa basin. Avocational archaeologists excavated a small portion of the exposed bonebed in the early 1970s and reported flakes in association with the skeletal remains. Limited reinvestigations of the site were undertaken in 2001, and a monthlong excavation was conducted in 2002 to assess the stratigraphy, geochronology, and archaeology. The bonebed is 35 ni long in a buried soil developed in fine-grained basin fill overlain by early Holocene alluvium (arroyo fill). Recent alluvium overlies a soil developed in the early Holocene alluvium, and modern deposits of eolian sand 2 to to points and a flake tool discovered in the bone bed, and a biface and Allen point fragment in disturbed bonebed deposits. Excavation of 9 m2 of the bone bed revealed some fully articulated skeletons, and taphonomic observations suggest some of the bison collapsed while standing in a playa or pond margin setting. The remains of at least six bison are represented in the excavated sample from 2002, but many more animals are represented in the bonebed. A 14C age of ca. 9000 yr B.P. was determined on collagen from bison rib fragments. This age is consistent with the diagnostic artifacts found at Winger. ?? 2003 Wiley Periodicals, Inc.

  16. Concentrations of selected trace inorganic constituents and synthetic organic compounds in the water-table aquifers in the Memphis area, Tennessee

    Science.gov (United States)

    McMaster, B.W.; Parks, William Scott

    1988-01-01

    Water quality samples for analysis of selected trace inorganic constituents and synthetic organic compounds were collected from 29 private or observation wells in alluvium and fluvial deposits of Quaternary and Tertiary Age. The alluvium and fluvial deposits are the water table aquifers in the Memphis area. In addition, nine wells were installed in Memphis Light, Gas and Water Division well fields so that samples could be collected and analyzed to characterize the quality of water in the fluvial deposits at these well fields. Samples from seven of these wells (two were dry) were analyzed for major constituents and properties of water as well as for selected trace inorganic constituents and synthetic organic compounds. Analyses of the water from most of the 36 wells sampled indicated ranges in concentration values for the trace inorganic constituents that agreed with those previously known, although some new maximum values were established. The analysis of water from four wells indicated that the water is or may be contaminated. Concentrations of barium (1,400 micrograms/L -- ug/L), strontium (1,100 ug/L), and arsenic (15 ug/L), along with specific conductance (1,420 microsiemens/centimeter--us/cm) were in water from one well in the alluvium. Low concentrations (0.02 to 0.04 ug/L) of the pesticides aldrin, DDT, endosulfan, and perthane were present in water from two wells in the fluvial deposits. Water from one of these wells also contained 1,1,1 trichloroethane (4.4 ug/L). Analysis of water from another well in the fluvial deposits indicated values for specific conductance (1,100 uS/cm), alkalinity (508 milligrams per liter -- mg/L -- as CaCO3), hardness (550 mg/L as CaCO3), chloride (65 mg/L), and barium (240 ug/L) that are high for water from the fluvial deposits. (USGS)

  17. Characterizing Shorea robusta communities in the part of Indian Terai landscape

    Institute of Scientific and Technical Information of China (English)

    V. S. Chitale; M. D. Behera; S. Matin; P. S. Roy; V. K. Sinha

    2014-01-01

    Shorea robusta Gaertn. f.(Sal)is one of the important tim-ber-yielding plants in India, which dominates the vegetation of Terai landscape of Uttar Pradesh state in India forming various communities based on its associations. The present study deals with delineation, map-ping and characterization of various communities of Sal (Shorea robusta) forests in Terai landscape of Uttar Pradesh, India ranging across over 16 districts. Field survey and visual interpretation based forest vegetation type classification and mapping was carried out as part of the project entitled ‘Biodiversity characterization at landscape level using remote sensing and GIS’. Indian Remote Sensing-P6 (Resourcesat-1) Linear Imaging Self Scanner-III satellite data was used during the study. The total area covered by different Sal forests was found to be approximately 2256.77 km2. Sal communities were identified and characterized based on their spectral properties, physiognomy and phytosociological charac-teristics. Following nine Sal communities were identified, delineated and mapped with reasonable accuracyviz.,Chandar,Damar, dry plains, moist plains, western alluvium, western alluvium plains, mixed moist deciduous, mixed dry deciduous andSiwalik. It is evident from the area estimates that mixed moist deciduous Sal is the most dominant commu-nity in the region covering around (1613.90 km2), other major communi-ties were found as western alluvium plains Sal (362.44 km2), mixed dry deciduous Sal (362.44 km2) and dry plains Sal (107.71 km2). The Terai landscape of Uttar Pradesh faces tremendous anthropogenic pressure leading to deterioration of the forests. Community level information could be used monitoring the status as well as for micro level conserva-tion and planning of the Sal forests in Terai Landscape of Uttar Pradesh.

  18. Evaluating the reliability of Late Quaternary landform ages: Integrating 10Be cosmogenic surface exposure dating with U-series dating of pedogenic carbonate on alluvial and fluvial deposits, Sonoran desert, California

    Science.gov (United States)

    Blisniuk, K.; Sharp, W. D.

    2015-12-01

    To assess the reliability of Quaternary age determinations of alluvial and fluvial deposits across the Sonoran Desert (Coachella Valley and Anza Borrego) in southern California, we applied both 10Be exposure age dating of surface clasts and U-series dating of pedogenic carbonate from subsurface clast-coatings to the same deposits. We consider agreement between dates from the two techniques to indicate reliable age estimates because each technique is subject to distinct assumptions and therefore their systematic uncertainties are largely independent. 10Be exposure dates should yield maximum ages when no correction is made for inheritance and post-depositional erosion is negligible. U-series dating, in contrast, provides minimum dates because pedogenic carbonate forms after deposition. Our results show that: (1) For deposits ca. 70 ka or younger, 10Be and U-series dates were generally concordant. We note, however, that in most cases U-series soil dates exceed 10Be exposure dates that are corrected for inheritance when using 10Be in modern alluvium. This suggests that 10Be concentrations of modern alluvium may exceed the 10Be acquired by late Pleistocene deposits during fluvial transport and hillslope residence (i.e., Pleistocene inherited 10Be). (2) For deposits older than ~70 ka, U-series dates are significantly younger than the 10Be dates. This implies that U-series dates in this region may significantly underestimate the depositional age of older alluvium, probably because of delayed onset of deposition, slow accumulation, or poor preservation of secondary carbonate in response to climatic controls. Thus, whenever possible, multiple dating methods should be applied to obtain reliable ages for late Quaternary deposits.

  19. Sensitivity of long-term bare soil infiltration simulations to hydraulic properties in an arid environment

    Science.gov (United States)

    Stothoff, Stuart A.

    1997-04-01

    The suitability of Yucca Mountain, Nevada, for emplacement of a high-level nuclear waste geologic repository is currently being evaluated. Assessments of the repository performance suggest that the uncertainty in infiltration rates strongly affects predicted repository performance. Most of the ground surface over the potential repository footprint is characterized by shallow to deep colluvium/alluvium overlying densely fractured, welded tuffs. In order to identify characteristic behavior of infiltration that might be expected at the site, two idealizations of this situation are examined: an effectively semi-infinite column of alluvium and a two-layer column of alluvium over a fractured impermeable matrix. For each idealization the impact of hydraulic properties is assessed. Examining the sensitivity of bare soil simulator predictions for an effectively semi-infinite column, it is found that decreasing the air entry pressure while holding all other parameters at a fixed level tends to increase both the long-term average moisture content and the long-term average net infiltration flux for homogeneous media. In contrast, increasing the van Genuchten scale parameter (m=1 - 17sol;n) or decreasing the porosity tends to decrease the average soil moisture but increase the infiltration. Most interestingly, three regimes are found for permeability. For relatively high permeabilities, there is a trend toward increasing average infiltration and increasing average moisture content with decreasing permeability. For relatively low permeabilities, vapor transport dominates over liquid transport, runoff and evaporation overwhelm infiltration, and the soil becomes very dry with essentially no infiltration flux. Between the extreme cases of high and low permeability, there is a zone where decreasing permeability results in decreased infiltration but increased moisture content, which is explained by the capacity of more permeable media to maintain surface wetness for longer periods of

  20. Comment on ''Sensitivity Analysis and Determination of Streambed Leakance and Aquifer Hydraulic Properties'' by Xunhong Chen and Xi Chen, Journal of Hydrology, 2003, v.284, 270-284

    Energy Technology Data Exchange (ETDEWEB)

    Kollet, S

    2004-05-17

    Recently, studies of the Platte River watershed have gained significant attention from federal and Nebraska, USA, state agencies due to the importance of groundwater/surface-water interactions under drought conditions. Using archive data from a 1983 pumping test, Chen and Chen (2003) interpret the hydraulic properties of the alluvium and a streambed of the Platte River near Kearney, Nebraska, and compare their data with results of other studies performed over the past several years. Three important inconsistencies of this article will be highlighted here: (1) misuse of the analytical model of Hunt (1999), (2) departure of their results from previously published data, and (3) unsatisfactory explanation of these anomalous results.

  1. SATURATED ZONE IN-SITU TESTING

    Energy Technology Data Exchange (ETDEWEB)

    P.W. REIMUS

    2004-11-08

    The purpose of this scientific analysis is to document the results and interpretations of field experiments that test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain, Nevada. The test interpretations provide estimates of flow and transport parameters used in the development of parameter distributions for total system performance assessment (TSPA) calculations. These parameter distributions are documented in ''Site-Scale Saturated Zone Flow Model (BSC 2004 [DIRS 170037]), Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]), Saturated Zone Colloid Transport (BSC 2004 [DIRS 170006]), and ''Saturated Zone Flow and Transport Model Abstraction'' (BSC 2004 [DIRS 170042]). Specifically, this scientific analysis contributes the following to the assessment of the capability of the SZ to serve as part of a natural barrier for waste isolation for the Yucca Mountain repository system: (1) The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain. (2) Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters. (3) Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvial Testing Complex (ATC) located at the southwestern corner of the Nevada Test Site (NTS). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass

  2. Mercury dispersal to arroyo and coastal sediments from abandoned copper mine operations, el Boléo, Baja California.

    Science.gov (United States)

    Kot, Fyodor; Shumilin, Evgueni; Rodríguez-Figueroa, Griselda Margarita; Mirlean, Nicolai

    2009-01-01

    Evidence for mercury dispersal in an arid coastal region of central Baja California (Mexico) suggests that abandoned copper mining operations are a noticeable source of mercury in the environment. There is a generally elevated level of mercury in alluvium of arroyos throughout the mining district (0.14-0.18 mg kg(-1)). In the first several dozen meters surrounding two of the biggest mines, mercury levels range from 0.26 to 3.16 mg kg(-1), forming a halo of anomalously high concentrations. The coastal marine sediments, particularly those close to the copper smelter in the town of Santa Rosalía, also display some mercury enrichment. PMID:18800200

  3. Mercury dispersal to arroyo and coastal sediments from abandoned copper mine operations, El Boléo, Baja California

    OpenAIRE

    Kot, Fydor; Shumilin, Evgueni; Rodríguez Figueroa, Griselda Margarita; Mirlean, Nicolai

    2009-01-01

    Evidence for mercury dispersal in an arid coastal region of central Baja California (Mexico) suggests that abandoned copper mining operations are a noticeable source of mercury in the environment. There is a generally elevated level of mercury in alluvium of arroyos throughout the mining district (0.14–0.18 mg kg-1). In the first several dozen meters surrounding two of the biggest mines, mercury levels range from 0.26 to 3.16 mg kg-1, forming a halo of anomalously high concentrations. The coa...

  4. Optical dating using feldspar from Quaternary alluvial and colluvial sediments from SE Brazilian Plateau, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Tatumi, Sonia H. E-mail: tatumi@fatecsp.br; Peixoto, Maria Naise O.; Moura, Josilda R.S.; Mello, Claudio L.; Carmo, Isabela O.; Kowata, Emilia A.; Yee, Marcio; Brito, Silvio Luiz M.; Gozzi, Giuiliano; Kassab, Luciana R.P

    2003-05-01

    Opticallly stimulated luminescence (OSL) dating has been applied to a wide variety of materials such as loess, sand dunes, colluvium, alluvium, volcanic products, etc., helping geologic geomorphologic studies. OSL dating results using feldspar crystals extracted from alluvial and colluvial deposits of SE Brazilian Plateau will be presented in this work. The methodology used is based on the regeneration method, with multiple aliquot protocol. A total of 23 sample ages were obtained spanning 6.5-97.2 kyr. Results of radioactive contents and comparison with radiocarbon ages will be discussed.

  5. 新潟平野における表層地質中のヒ素濃度分布 : 地下水ヒ素汚染問題におけるヒ素の供給源の検討 その1

    OpenAIRE

    久保田, 喜裕; 石山, 豊; 横田, 大樹; Kubota, Yoshihiro; Ishiyama, Yutaka; Yokota, Daiki

    2000-01-01

    In order to consider source supply of arsenic in arsenic contaminated ground waters, the arsenic distribution in the surface geology of the Niigata Plain was investigated from the view point of alluvium forming processes. The following conclusions were reached : 1) Arsenic concentration in the surface geology is 0.1~2ppm for igneous rocks, 3~5ppm for sandstones and 8~12ppm for mudstones. Arsenic concentration in muddy facies were higher than others. Arsenic concentration increases in the soil...

  6. A probabilistic approach for earthquake hazard assessment of the Province of Eski?ehir, Turkey

    OpenAIRE

    A. Orhan; E. Seyrek; H. Tosun

    2007-01-01

    International audience The city of Eski?ehir in inner-western Turkey has experienced a destructive earthquake with Ms=6.4 in 1956 in addition to many events with magnitudes greater than 5. It is located in a wide basin having young sedimentary units and thick alluvium soils which also include liquefiable sand materials. There is also an active fault passing beneath the city center and the groundwater level is very close to the ground surface. Approximately 600 thousand people are living in...

  7. A probabilistic approach for earthquake hazard assessment of the Province of Eskişehir, Turkey

    OpenAIRE

    A. Orhan; E. Seyrek; H. Tosun

    2007-01-01

    The city of Eskişehir in inner-western Turkey has experienced a destructive earthquake with Ms=6.4 in 1956 in addition to many events with magnitudes greater than 5. It is located in a wide basin having young sedimentary units and thick alluvium soils which also include liquefiable sand materials. There is also an active fault passing beneath the city center and the groundwater level is very close to the ground surface. Approximately 600 thousand peop...

  8. Morphology and Quaternary geology of the Thames floodplain around Oxford

    OpenAIRE

    Newell, A.J.

    2008-01-01

    This report provides a summary of work undertaken on the geology and morphology of the River Thames floodplain around Oxford in the 13 km reach between Cassington in the northwest and Sandford-on-Thames in the southeast. The major part of the work was constructing 3D models and thickness maps of the valley gravels and alluvium using ArcGIS in conjunction with the 3D visualisation packages GSI3D and GOCAD. This work requires consideration of the available digital terrain models and how man-mad...

  9. Geohydrologic reconnaissance of Lake Mead National Recreation Area; Las Vegas Wash to Opal Mountain, Nevada

    Science.gov (United States)

    Laney, R.L.

    1981-01-01

    The study is a geohydrologic reconnaissance of about 170 square miles in the Lake Mead National Recreation Area from Las Vegas Wash to Opal Mountain, Nevada. The study is one of a series that describes the geohydrology of the recreation area and that indentifies areas where water supplies can be developed. Precipitation in this arid area is about 5 inches per year. Streamflow is seasonal and extremely variable except for that in the Colorado River, which adjoins the area. Pan evaporation is more than 20 times greater than precipitation; therefore, regional ground-water supplies are meager except near the Colorado River, Lake Mead, and Lake Mohave. Large ground-water supplies can be developed near the river and lakes, and much smaller supplies may be obtained in a few favorable locations farther from the river and lakes. Ground water in most of the areas probably contains more than 1,000 milligrams per liter of dissolved solids, but water that contains less than 1,000 milligrams per liter of dissolved solids can be obtained within about 1 mile of the lakes. Crystalline rocks of metamorphic, intrusive and volcanic origin crop out in the area. These rocks are overlain by conglomerate and mudstone of the Muddy Creek Formation, gravel and conglomerate of the older alluvium, and sand and gravel of the Chemehuevi Formation and younger alluvium. The crystalline rocks, where sufficiently fractured, yield water to springs and would yield small amounts of water to favorably located wells. The poorly cemented and more permeable beds of the older alluvium, Chemehuevi Formation, and younger alluvium are the better potential aquifers, particularly along the Colorado River and Lakes Mead and Mohave. Thermal springs in the gorge of the Colorado River south of Hoover Dam discharge at least 2,580 acre-feet per year of water from the volcanic rocks and metamorphic and plutonic rocks. The discharge is much greater than could be infiltrated in the drainage basin above the springs

  10. Design on Buffer Structure of Traction Running with a Constant Speed

    Directory of Open Access Journals (Sweden)

    Zeng Xianren

    2013-06-01

    Full Text Available This study mainly aims to study buffer structure design on the traction transport system when the traction transport boundary conditions are given. With such conditions as the maximum impact force, traction speed, maximum speed of alluvium, the elasticity coefficient and the mass of buffer structure, a mathematical model was established and the solution of differential equations was solved. At last, a program was compiled with MATLAB language. With this program the elasticity coefficient and the maximum impact force which meet the requirements in impact process can be solved as long as the boundary conditions are input. This provides a quick design basis of buffer structure for most mechanical engineers.

  11. Alpha-emitting isotopes and chromium in a coastal California aquifer

    International Nuclear Information System (INIS)

    Highlights: • Alluvium in Piedra de Lumbre basin higher radionuclides likely from natural Th. • Natural uranium decay-chain isotopes, including Ra, present in marine deposits. • Marine deposits also contain low concentrations of chromium. • Radionuclides and chromium concentrations lower in alluvium in the Las Flores basin. - Abstract: The unadjusted 72-h gross alpha activities in water from two wells completed in marine and alluvial deposits in a coastal southern California aquifer 40 km north of San Diego were 15 and 25 picoCuries per liter (pCi/L). Although activities were below the Maximum Contaminant Level (MCL) of 15 pCi/L, when adjusted for uranium activity; there is concern that new wells in the area may exceed MCLs, or that future regulations may limit water use from the wells. Coupled well-bore flow and depth-dependent water-quality data collected from the wells in 2011 (with analyses for isotopes within the uranium, actinium, and thorium decay-chains) show gross alpha activity in marine deposits is associated with decay of naturally-occurring 238U and its daughter 234U. Radon activities in marine deposits were as high as 2230 pCi/L. In contrast, gross alpha activities in overlying alluvium within the Piedra de Lumbre watershed, eroded from the nearby San Onofre Hills, were associated with decay of 232Th, including its daughter 224Ra. Radon activities in alluvium from Piedra de Lumbre of 450 pCi/L were lower than in marine deposits. Chromium VI concentrations in marine deposits were less than the California MCL of 10 μg/L (effective July 1, 2014) but δ53Cr compositions were near zero and within reported ranges for anthropogenic chromium. Alluvial deposits from the nearby Las Flores watershed, which drains a larger area having diverse geology, has low alpha activities and chromium as a result of geologic and geochemical conditions and may be more promising for future water-supply development

  12. Detection of a buried horizon with a high thermal diffusivity using thermal remote sensing

    Science.gov (United States)

    Nash, David B.

    1988-01-01

    A field investigation using thermal remote sensing was performed to test the feasibility of detecting the surface topography of granite bedrock beneath a thin cover of alluvium. Imagery of a region of the Mojave Desert were taken with an airborne multispectral scanner with thermal spectral bandwidths of 10.4 and 12.5 microns an instantaneous field of view of 2.5 mrad. It is suggested that a buried high thermal diffusivity horizon measurably lowers the surface temperature of the overlying lower diffusivity material during the peak of the annual heating cycle.

  13. Carbon and Isotopic Mass Balance Models of Oasis Valley-Fortymile Canyon Groundwater Basin, Southern Nevada

    Science.gov (United States)

    White, Art F.; Chuma, Nancy J.

    1987-04-01

    Environmental isotopes and carbon chemistry provide means of differentiating various recharge areas, flow paths, and ages of groundwater in portions of the Nevada Test Site and vicinity. Regional δD/δ18O trends are offset from the present-day meteoric line by a deuterium depletion of 5‰, suggesting paleoclimatic changes. Partial pressures of CO2 and the 18O and 13C data indicate solubility and isotopic equilibrium between the gas and water in the soil zone with progressive exchange with underlying groundwater in the shallow alluvium of Oasis Valley. Application of a closed system CO2 model using the EQ3NR/EQ6 reaction path simulator successfully reproduces chemical compositions observed in the alluvium in the Amargosa Desert and in the deep tuff aquifer beneath Pahute Mesa and Yucca Mountain. Initial PCO2 input to the soil zone during recharge was calculated to range from 0.03 to 0.10 atm, which is comparable to measured soil CO2 pressures in Oasis Valley. Results are compared for 14C ages using the δ13C dilution correction and a mass action correction term relating predicted and calculated ionic activity products of CaCO3. Results are generally comparable with discrepancies attributed to anomalous δ13C values.

  14. Aquifer response to regional climate variability in a part of Kashmir Himalaya in India

    Science.gov (United States)

    Jeelani, Gh

    2008-12-01

    Forty major perennial springs, under different lithological controls, in a part of Kashmir Himalaya in India were studied to understand the response of spring discharges to regional climate variability. The average monthly spring discharge is high in Triassic Limestone-controlled springs (karst springs) and low in alluvium- and Karewa-controlled springs. In general, the measured monthly spring discharges show an inverse relation with the monthly precipitation data. However, a direct correlation exists between the spring discharges and the degree of snow/ice melt. The results suggest that the creation of a low and continuous (but stable) recharge from the Triassic Limestone and Panjal Trap aquifers, due to blockage of groundwater flow between strata with contrasting hydraulic conductivity, attenuates the discharge and gives rise to small fluctuations in the alluvium- and Karewa-controlled springs. The average monthly discharge of the karst and alluvial springs showed an overall decreasing trend for two and a half decades, with the lowest discharge recorded in 2001. The study revealed that the regional/global warming and below-normal precipitation in the period of snow accumulation (PSA) has triggered the receding of glaciers and attenuation of spring discharges.

  15. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Shiprock, New Mexico

    International Nuclear Information System (INIS)

    This baseline risk assessment at the former uranium mill tailings site near Shiprock, New Mexico, evaluates the potential impact to public health or the environment resulting from ground water contamination at the former uranium mill processing site. The tailings and other contaminated material at this site were placed in an on-site disposal cell in 1986 through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating ground water contamination. This risk assessment is the first document specific to this site for the Ground Water Project. There are no domestic or drinking water wells in the contaminated ground water of the two distinct ground water units: the contaminated ground water in the San Juan River floodplain alluvium below the site and the contaminated ground water in the terrace alluvium area where the disposal cell is located. Because no one is drinking the affected ground water, there are currently no health or environmental risks directly associated with the contaminated ground water. However, there is a potential for humans, domestic animals, and wildlife to the exposed to surface expressions of ground water in the seeps and pools in the area of the San Juan River floodplain below the site. For these reasons, this risk assessment evaluates potential exposure to contaminated surface water and seeps as well as potential future use of contaminated ground water

  16. Seismic ground motion analysis of Shanghai Pudong Airport site considering the effects of spatial correlation and irregular topography

    Institute of Scientific and Technical Information of China (English)

    JIANG Tong; CHEN Laiyun; XING Hailing; L(U) Xilin

    2007-01-01

    The terminal No.Ⅱ of Shanghai Pudong International Airport is located at Pudong District of Shanghai City near shore of East China Sea,and the area of the long-span terminal is 400 m × 200 m.The construction site of the terminal locates on the irregular topography,and its alluvium achieves about 300 m in thickness.The spatial correlation of seismic ground motion,as well as the amplification of soft alluvium and the effect of irregular topography,should be considered.This paper uses a simplified method to obtain the response spectrum of the engineering bedrock under the irregular topography.The spectrum is used to generate the sets of spatially correlative horizontal and vertical seismic motions.The surface ground motion was calculated under incidence of the spatially correlative seismic motion by 2D finite element method (FEM) model considering nonlinear properties of the soil by means of the equivalent linear method.In order to compare the effect of 2D irregular topography,the seismic response analysis of 1D model is carried out by using the equivalent linear method.For indicating the effect of the spatial correlation of input motions,the horizontal uniform inputs,as well as the horizontal and vertical uniform input are carried out for the seismic response analysis of the site.Finally,some characteristics of seismic ground motion calculated for previously mentioned cases are compared.

  17. Appraisal of nuclear waste isolation in the vadose zone in arid and semiarid regions (with emphasis on the Nevada Test Site)

    Energy Technology Data Exchange (ETDEWEB)

    Wollenberg, H.A.; Wang, J.S.Y.; Korbin, G.

    1983-05-01

    An appraisal was made of the concept of isolating high-level radioactive waste in the vadose zone of alluvial-filled valleys and tuffaceous rocks of the Basin and Range geomorphic province. Principal attributes of these terranes are: (1) low population density, (2) low moisture influx, (3) a deep water table, (4) the presence of sorptive rocks, and (5) relative ease of construction. Concerns about heat effects of waste on unsaturated rocks of relatively low thermal conductivity are considered. Calculations show that a standard 2000-acre repository with a thermal loading of 40 kW/acre in partially saturated alluvium or tuff would experience an average temperature rise of less than 100{sup 0}C above the initial temperature. The actual maximum temperature would depend strongly on the emplacement geometry. Concerns about seismicity, volcanism, and future climatic change are also mitigated. The conclusion reached in this appraisal is that unsaturated zones in alluvium and tuff of arid regions should be investigated as comprehensively as other geologic settings considered to be potential repository sites.

  18. Verification of a 1-dimensional model for predicting shallow infiltration at Yucca Mountain

    International Nuclear Information System (INIS)

    A characterization of net infiltration rates is needed for site-scale evaluation of groundwater flow at Yucca Mountain, Nevada. Shallow infiltration caused by precipitation may be a potential source of net infiltration. A 1-dimensional finite difference model of shallow infiltration with a moisture-dependent evapotranspiration function and a hypothetical root-zone was calibrated and verified using measured water content profiles, measured precipitation, and estimated potential evapotranspiration. Monthly water content profiles obtained from January 1990 through October 1993 were measured by geophysical logging of 3 boreholes located in the alluvium channel of Pagany Wash on Yucca Mountain. The profiles indicated seasonal wetting and drying of the alluvium in response to winter season precipitation and summer season evapotranspiration above a depth of 2.5 meters. A gradual drying trend below a depth of 2.5 meters was interpreted as long-term redistribution and/or evapotranspiration following a deep infiltration event caused by runoff in Pagany Wash during 1984. An initial model, calibrated using the 1990 to 1992 record, did not provide a satisfactory prediction of water content profiles measured in 1993 following a relatively wet winter season. A re-calibrated model using a modified, seasonally-dependent evapotranspiration function provided an improved fit to the total record. The new model provided a satisfactory verification using water content changes measured at a distance of 6 meters from the calibration site, but was less satisfactory in predicting changes at a distance of 18 meters

  19. Soils, surficial geology, and geomorphology of the Bear Creek Valley Low-Level Waste Disposal Development and Demonstration Program site

    Energy Technology Data Exchange (ETDEWEB)

    Lietzke, D.A.; Lee, S.Y.; Lambert, R.E.

    1988-04-01

    An intensive soil survey was conducted on the proposed Low-Level Waste Disposal Development and Demonstration Program site (LLWDDD) in Bear Creek Valley. Soils on the site were related to the underlying residuum and to the surficial colluvium and alluvium. Within any particular geologic formation, soils were subdivided based mostly on the degree of weathering, as reflected by saprolite weathering and morphologic features of the soils. Degree of weathering was related both to slope shape and gradient and to the joint-fracture system. Erosion classes were also used to make further subdivisions of any particular soil. Deep pits were dug in each of the major Conasauga Group formations (Pumpkin Valley, Rogersville, Maryville, and Nolichucky) for soil and saprolite characterization. Because of the widespread presence of alluvium and colluvium, which are potential sources of fill and final cover material, pits and trenches were dug to characterize the properties of these soils and to try to understand the past geomorphic history of the site. The results of the soil survey investigation indicated that the deeply weathered Pumpkin Valley residuum has good potential for the construction of tumuli or other types of belowground or aboveground burial of prepackaged compacted waste. 11 refs., 30 figs., 3 tabs.

  20. Soils, surficial geology, and geomorphology of the Bear Creek Valley Low-Level Waste Disposal Development and Demonstration Program site

    International Nuclear Information System (INIS)

    An intensive soil survey was conducted on the proposed Low-Level Waste Disposal Development and Demonstration Program site (LLWDDD) in Bear Creek Valley. Soils on the site were related to the underlying residuum and to the surficial colluvium and alluvium. Within any particular geologic formation, soils were subdivided based mostly on the degree of weathering, as reflected by saprolite weathering and morphologic features of the soils. Degree of weathering was related both to slope shape and gradient and to the joint-fracture system. Erosion classes were also used to make further subdivisions of any particular soil. Deep pits were dug in each of the major Conasauga Group formations (Pumpkin Valley, Rogersville, Maryville, and Nolichucky) for soil and saprolite characterization. Because of the widespread presence of alluvium and colluvium, which are potential sources of fill and final cover material, pits and trenches were dug to characterize the properties of these soils and to try to understand the past geomorphic history of the site. The results of the soil survey investigation indicated that the deeply weathered Pumpkin Valley residuum has good potential for the construction of tumuli or other types of belowground or aboveground burial of prepackaged compacted waste. 11 refs., 30 figs., 3 tabs

  1. Delineation of Holocene-Pleistocene aquifer system in parts of Middle Ganga Plain, Bihar, Eastern India through DC resistivity survey

    Science.gov (United States)

    Ganguli, Shuva Shankha; Singh, Shashikant

    2014-07-01

    The study area forms a part of the Middle Ganga Plain (MGP) and experiences intensive groundwater draft due to domestic, irrigation and industrial purposes. Geoelectrical surveys were carried out in a geomorphic unit of MGP called South Ganga Plain, along the north-south traverse covering a total 50 km stretch. Interpreted results of the total of 17 vertical electrical soundings, carried out, provided information on aquifer and aquitard geometry and sediment nature in different aquifer systems. Bedrock topography is also demarcated along the north-south transect. The estimated dip of massive bedrock is less than 0.5° and dips toward north. The survey results show that a two-tier aquifer system exists in Newer alluvium parts of the study area and it is replaced by a single aquifer system at Older alluvium that occurs under thick clay/sandy clay bed in the southern part. An exponential decay of the aquifer potential is observed from north to south. Paleo channel Sone River is traced and it forms a potential aquifer.

  2. Site response, shallow shear-wave velocity, and damage in Los Gatos, California, from the 1989 Loma Prieta earthquake

    Science.gov (United States)

    Hartzell, S.; Carver, D.; Williams, R.A.

    2001-01-01

    Aftershock records of the 1989 Loma Prieta earthquake are used to calculate site response in the frequency band of 0.5-10 Hz at 24 locations in Los Gatos, California, on the edge of the Santa Clara Valley. Two different methods are used: spectral ratios relative to a reference site on rock and a source/site spectral inversion method. These two methods complement each other and give consistent results. Site amplification factors are compared with surficial geology, thickness of alluvium, shallow shear-wave velocity measurements, and ground deformation and structural damage resulting from the Loma Prieta earthquake. Higher values of site amplification are seen on Quaternary alluvium compared with older Miocene and Cretaceous units of Monterey and Franciscan Formation. However, other more detailed correlations with surficial geology are not evident. A complex pattern of alluvial sediment thickness, caused by crosscutting thrust faults, is interpreted as contributing to the variability in site response and the presence of spectral resonance peaks between 2 and 7 Hz at some sites. Within the range of our field measurements, there is a correlation between lower average shear-wave velocity of the top 30 m and 50% higher values of site amplification. An area of residential homes thrown from their foundations correlates with high site response. This damage may also have been aggravated by local ground deformation. Severe damage to commercial buildings in the business district, however, is attributed to poor masonry construction.

  3. Fission-track dating of the punta de vacas glaciation in the Rı´o Mendoza valley, Argentina.

    Science.gov (United States)

    Espizua, L. E.; Bigazzi, G.

    Fission-track dating of three tephra samples related to mappable drifts and non-glacial sediments, including alluvium, in the Rı´o Mendoza valley, Argentina, places limiting ages on the oldest two glacial events. A tephra-layer interstratified with fan alluvium that surrounds and cuts the outermost Uspallata moraine has an age of 170,000±50,000 yr, implying that the drift predates marine oxygen isotope stage (OIS) 6. A tephra dated at 134,000±32,000 yr, that was deposited on alluvial fan sediments, underlies Punta de Vacas drift, which is inferred to equate with Isotope Stage 6. The Punta de Vacas outwash, which likely correlates with the Rı´o Colorado drift, overlies another tephra unit that dates to 260,000±150,000 yr. Although the error limits of the dates preclude definitive correlations, all three tephra units may have been deposited during an interval prior to the maximum advance of the Punta de Vacas glaciation during OIS 6 or maybe in the Stage 7 interglacial period.

  4. Baseline risk assessment of ground water contamination at the Uranium Mill Tailings Site near Shiprock, New Mexico. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    1994-04-01

    This baseline risk assessment at the former uranium mill tailings site near Shiprock, New Mexico, evaluates the potential impact to public health or the environment resulting from ground water contamination at the former uranium mill processing site. The tailings and other contaminated material at this site were placed in an on-site disposal cell in 1986 through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating ground water contamination. This risk assessment is the first document specific to this site for the Ground Water Project. There are no domestic or drinking water wells in the contaminated ground water of the two distinct ground water units: the contaminated ground water in the San Juan River floodplain alluvium below the site and the contaminated ground water in the terrace alluvium area where the disposal cell is located. Because no one is drinking the affected ground water, there are currently no health or environmental risks directly associated with the contaminated ground water. However, there is a potential for humans, domestic animals, and wildlife to the exposed to surface expressions of ground water in the seeps and pools in the area of the San Juan River floodplain below the site. For these reasons, this risk assessment evaluates potential exposure to contaminated surface water and seeps as well as potential future use of contaminated ground water.

  5. Geohydrology of part of the Round Valley Indian Reservation, Mendocino County, California

    Science.gov (United States)

    Muir, K.S.; Webster, Dwight Albert

    1977-01-01

    The Round Valley Indian Reservation in northern California obtains most of its water from the ground-water reservoir. The ground-water reservoir is made up of continental deposits, alluvium, and stream-channel deposits ranging in age from Pliocene to Holocene. Most of the water is pumped from the alluvium. Most ground water (about 20,000 acre-feet or 25 cubic hectometers per year) is derived from stream seepage. Natural discharge (discharge to streams, evapotranspiration, and underflow) has averaged about 21,000 acre-feet per year. Pumping and flow from artesian wells has averaged about 2,750 acre-feet per year. Ground water occurs in both confined and unconfined aquifers. The ground-water reservoir is full, and about 230,000 acre-feet of water is stored in the depth interval 10-200 feet. The water is chemically and biologically suitable for domestic or irrigation use, although hardness is high for domestic use and, locally, dissolved iron is a problem. There is potential for developing additional ground-water supplies. (Woodard-USGS)

  6. Remedial action at the Green River uranium mill tailings site, Green River, Utah: Environmental assessment

    International Nuclear Information System (INIS)

    The inactive Green River uranium mill tailings site is one mile southeast of Green River, Utah. The existing tailings pile is within the floodplain boundaries of the 100-year and 500-year flood events. The 48-acre designated site contains eight acres of tailings, the mill yard and ore storage area, four main buildings, a water tower, and several small buildings. Dispersion of the tailings has contaminated an additional 24 acres surrounding the designated site. Elevated concentrations of molybdenum, nitrate, selenium, uranium, and gross alpha activity exceed background levels and the proposed US Environmental Protection Agency (EPA) maximum concentration limits in the groundwater in the unconsolidated alluvium and in the shallow shales and limestones beneath the alluvium at the mill tailings site. The contamination is localized beneath, and slightly downgradient of, the tailings pile. The proposed action is to relocate the tailings and associated contaminated materials to an area 600 feet south of the existing tailings pile where they would be consolidated into one, below-grade disposal cell. A radon/infiltration barrier would be constructed to cover the stabilized pile and various erosion control measures would be taken to ensure the long-term stability of the stabilized pile. 88 refs., 12 figs., 20 tabs

  7. Appraisal of nuclear waste isolation in the vadose zone in arid and semiarid regions (with emphasis on the Nevada Test Site)

    International Nuclear Information System (INIS)

    An appraisal was made of the concept of isolating high-level radioactive waste in the vadose zone of alluvial-filled valleys and tuffaceous rocks of the Basin and Range geomorphic province. Principal attributes of these terranes are: (1) low population density, (2) low moisture influx, (3) a deep water table, (4) the presence of sorptive rocks, and (5) relative ease of construction. Concerns about heat effects of waste on unsaturated rocks of relatively low thermal conductivity are considered. Calculations show that a standard 2000-acre repository with a thermal loading of 40 kW/acre in partially saturated alluvium or tuff would experience an average temperature rise of less than 1000C above the initial temperature. The actual maximum temperature would depend strongly on the emplacement geometry. Concerns about seismicity, volcanism, and future climatic change are also mitigated. The conclusion reached in this appraisal is that unsaturated zones in alluvium and tuff of arid regions should be investigated as comprehensively as other geologic settings considered to be potential repository sites

  8. Chronostratigraphic study of the Grottaperfetta alluvial valley in the city of Rome (Italy: investigating possible interaction between sedimentary and tectonic processes

    Directory of Open Access Journals (Sweden)

    G. Di Giulio

    2008-06-01

    Full Text Available We carried out geomorphologic and geological investigations in a south-eastern tributary valley of the Tiber River in Rome, the Grottaperfetta valley, aimed to reconstruct its buried geometry. Since results of the geomorphologic study evidenced anomalies of the stream beds, we performed geoelectric and boreholes prospecting to check whether recent faulting, rather than an inherited structural control, possibly contributed to the evolution of the alluvial valley. Vertical offsets of the stratigraphic horizons across adjacent boreholes were evidenced within the Late Pleistocene-Holocene alluvium and its substratum. In order to rule out the effects of irregular geometry of the alluvial deposits, we focussed on sectors where vertical offsets affected all the stratigraphic horizons (alluvium and pre-Holocene substratum, showing an increasing displacement with depth. We identified a site where repeated displacements occur coupled with a lateral variation of soil resistivity, and we drilled an oblique borehole aimed to cross and sample the possible fault zone affecting the terrain. A 7 cm thick granular layer, inclined 50°÷70° on the horizontal, was recovered 5 m b.g., and it was interpreted as the filling material of a fracture. The convergence of the reported features with independent evidence from geoelectric and geomorphologic investigations leads to hypothesize the presence of a faulting zone within the Holocene alluvial terrains and to propose the excavation of a trench to verify this hypothesis.

  9. Geoelectric resistivity sounding of riverside alluvial aquifer in an agricultural area at Buyeo, Geum River watershed, Korea: an application to groundwater contamination study

    Science.gov (United States)

    Park, Yong-Hee; Doh, Seong-Jae; Yun, Seong-Taek

    2007-12-01

    Twenty profiles of vertical electric soundings (VES) were obtained in a riverside alluvium at the Buyeo area, South Korea, to examine the variations of subsurface geology and associated groundwater chemistry. The combination of the VES data with the borehole data provided useful information on subsurface hydrogeologic conditions. The vestige of an ancient river channel (e.g. oxbow lake) was identified on the resistivity profiles by the lateral continuation of a near-surface perched aquifer parallel to the river. Such a perched aquifer is typically developed in the area with a clay-rich silty surface alluvium which prohibits the infiltration of oxygen. Therefore, groundwater below the oxbow lake shows a very low nitrate concentration and Eh values under the strong anoxic condition. The distribution of water resistivity is correlated with that of measured total dissolved solids concentration in groundwater, while the earth resistivity of the aquifer shows a significant spatial variation. It is interpreted that the earth resistivity of the aquifer is mainly controlled by the soil type rather than by the water chemistry in the study area.

  10. Radon survey in the high natural radiation region of Niska Banja, Serbia.

    Science.gov (United States)

    Zunic, Z S; Yarmoshenko, I V; Birovljev, A; Bochicchio, F; Quarto, M; Obryk, B; Paszkowski, M; Celiković, I; Demajo, A; Ujić, P; Budzanowski, M; Olko, P; McLaughlin, J P; Waligorski, M P R

    2007-01-01

    A radon survey has been carried out around the town of Niska Banja (Serbia) in a region partly located over travertine formations, showing an enhanced level of natural radioactivity. Outdoor and indoor radon concentrations were measured seasonally over the whole year, using CR-39 diffusion type radon detectors. Outdoor measurements were performed at 56 points distributed over both travertine and alluvium sediment formations. Indoor radon concentrations were measured in 102 living rooms and bedrooms of 65 family houses. In about 50% of all measurement sites, radon concentration was measured over each season separately, making it possible to estimate seasonal variations, which were then used to correct values measured over different periods, and to estimate annual values. The average annual indoor radon concentration was estimated at over 1500 Bq/m3 and at about 650 Bq/m3 in parts of Niska Banja located over travertine and alluvium sediment formations, respectively, with maximum values exceeding 6000 Bq/m3. The average value of outdoor annual radon concentration was 57 Bq/m3, with a maximum value of 168 Bq/m3. The high values of indoor and outdoor radon concentrations found at Niska Banja make this region a high natural background radiation area. Statistical analysis of our data confirms that the level of indoor radon concentration depends primarily on the underlying soil and building characteristics.

  11. Radon survey in the high natural radiation region of Niska Banja, Serbia

    Energy Technology Data Exchange (ETDEWEB)

    Zunic, Z.S. [Institute of Nuclear Sciences ' Vinca' , P.O. Box 522, 11000 Belgrade (Serbia); Yarmoshenko, I.V. [Institute of Industrial Ecology, Ural Branch of Russian Academy of Sciences Ekaterinburg (Russian Federation)]. E-mail: ivy@ecko.uran.ru; Birovljev, A. [Radonlab Ltd., Akersveien 24C, 0177 Oslo (Norway); Bochicchio, F. [Istituto Superiore di Sanita - Italian National Institute of Health, Department of Technology and Health, Rome (Italy); Quarto, M. [Istituto Superiore di Sanita - Italian National Institute of Health, Department of Technology and Health, Rome (Italy); Obryk, B. [Institute of Nuclear Physics (IFJ), Polish Academy of Sciences, Radzikowskiego 152, 31-342 Cracow (Poland); Paszkowski, M. [Institute of Geological Sciences, Polish Academy of Sciences, Senacka 1, 31-342 Cracow (Poland); Celikovic, I. [Institute of Nuclear Sciences ' Vinca' , P.O. Box 522, 11000 Belgrade (Serbia); Demajo, A. [Institute of Nuclear Sciences ' Vinca' , P.O. Box 522, 11000 Belgrade (Serbia); Ujic, P. [Institute of Nuclear Sciences ' Vinca' , P.O. Box 522, 11000 Belgrade (Serbia); Budzanowski, M. [Institute of Nuclear Physics (IFJ), Polish Academy of Sciences, Radzikowskiego 152, 31-342 Cracow (Poland); Olko, P. [Institute of Nuclear Physics (IFJ), Polish Academy of Sciences, Radzikowskiego 152, 31-342 Cracow (Poland); McLaughlin, J.P. [University College Dublin, Belfield, Dublin 4 (Ireland); Waligorski, M.P.R. [Institute of Nuclear Physics (IFJ), Polish Academy of Sciences, Radzikowskiego 152, 31-342 Cracow (Poland); Maria Sklodowska-Curie Memorial Centre of Oncology, Cracow (Poland)

    2007-07-01

    A radon survey has been carried out around the town of Niska Banja (Serbia) in a region partly located over travertine formations, showing an enhanced level of natural radioactivity. Outdoor and indoor radon concentrations were measured seasonally over the whole year, using CR-39 diffusion type radon detectors. Outdoor measurements were performed at 56 points distributed over both travertine and alluvium sediment formations. Indoor radon concentrations were measured in 102 living rooms and bedrooms of 65 family houses. In about 50% of all measurement sites, radon concentration was measured over each season separately, making it possible to estimate seasonal variations, which were then used to correct values measured over different periods, and to estimate annual values. The average annual indoor radon concentration was estimated at over 1500 Bq/m{sup 3} and at about 650 Bq/m{sup 3} in parts of Niska Banja located over travertine and alluvium sediment formations, respectively, with maximum values exceeding 6000 Bq/m{sup 3}. The average value of outdoor annual radon concentration was 57 Bq/m{sup 3}, with a maximum value of 168 Bq/m{sup 3}. The high values of indoor and outdoor radon concentrations found at Niska Banja make this region a high natural background radiation area. Statistical analysis of our data confirms that the level of indoor radon concentration depends primarily on the underlying soil and building characteristics.

  12. Hydrochemical evolution of sodium-sulfate and sodium-chloride groundwater beneath the Northern Chihuahuan Desert, Trans-Pecos, Texas, USA

    Science.gov (United States)

    Fisher, R.S.; Mullican, W. F., III

    1997-01-01

    Groundwater beneath the northern Chihuahuan Desert, Trans-Pecos, Texas, USA, occurs in both carbonate and siliciclastic aquifers beneath a thick unsaturated zone and in shallow Rio Grande alluvium. Groundwater hydrochemical evolution was investigated by analyzing soils, soil leachates, bolson-fill sediments, water from the unsaturated zone, and groundwater from three major aquifers. Ionic relations, mineral saturation states, and geochemical modeling show that groundwater compositions are controlled by reactions in the unsaturated zone, mineralogy of unsaturated sediments and aquifers, position in the groundwater flow system, and extensive irrigation. Recharge to aquifers unaffected by irrigation is initially a Ca-HCO3 type as a result of dissolving carbonate surficial salts. With continued flow and mineral-water interaction, saturation with calcite and dolomite is maintained, gypsum is dissolved, and aqueous Ca and Mg are exchanged for adsorbed Na to produce a Na-SO4 water. Groundwater in Rio Grande alluvium is a Na-Cl type, reflecting river-water composition and the effects of irrigation, evapotranspiration, and surficial salt recycling. These results document two hydrochemical evolution paths for groundwater in arid lands. If recharge is dilute precipitation, significant changes in water chemistry can occur in unsaturated media, ion exchange can be as important as dissolution-precipitation reactions in determining groundwater composition, and mineral-water reactions ultimately control groundwater composition. If recharge is return flow of irrigation water that already contains appreciable solutes, mineral-water reactions are less important than irrigation-water composition in determining groundwater chemistry.

  13. Radon survey in the high natural radiation region of Niska Banja, Serbia.

    Science.gov (United States)

    Zunic, Z S; Yarmoshenko, I V; Birovljev, A; Bochicchio, F; Quarto, M; Obryk, B; Paszkowski, M; Celiković, I; Demajo, A; Ujić, P; Budzanowski, M; Olko, P; McLaughlin, J P; Waligorski, M P R

    2007-01-01

    A radon survey has been carried out around the town of Niska Banja (Serbia) in a region partly located over travertine formations, showing an enhanced level of natural radioactivity. Outdoor and indoor radon concentrations were measured seasonally over the whole year, using CR-39 diffusion type radon detectors. Outdoor measurements were performed at 56 points distributed over both travertine and alluvium sediment formations. Indoor radon concentrations were measured in 102 living rooms and bedrooms of 65 family houses. In about 50% of all measurement sites, radon concentration was measured over each season separately, making it possible to estimate seasonal variations, which were then used to correct values measured over different periods, and to estimate annual values. The average annual indoor radon concentration was estimated at over 1500 Bq/m3 and at about 650 Bq/m3 in parts of Niska Banja located over travertine and alluvium sediment formations, respectively, with maximum values exceeding 6000 Bq/m3. The average value of outdoor annual radon concentration was 57 Bq/m3, with a maximum value of 168 Bq/m3. The high values of indoor and outdoor radon concentrations found at Niska Banja make this region a high natural background radiation area. Statistical analysis of our data confirms that the level of indoor radon concentration depends primarily on the underlying soil and building characteristics. PMID:17196309

  14. Verification of a 1-dimensional model for predicting shallow infiltration at Yucca Mountain

    Energy Technology Data Exchange (ETDEWEB)

    Hevesi, J.A.; Flint, A.L. [Geological Survey, Mercury, NV (United States); Flint, L.E. [Foothill Engineering Consultants, Mercury, Nevada (United States)

    1994-12-31

    A characterization of net infiltration rates is needed for site-scale evaluation of groundwater flow at Yucca Mountain, Nevada. Shallow infiltration caused by precipitation may be a potential source of net infiltration. A 1-dimensional finite difference model of shallow infiltration with a moisture-dependant evapotranspiration function and a hypothetical root-zone was calibrated and verified using measured water content profiles, measured precipitation, and estimated potential evapotranspiration. Monthly water content profiles obtained from January 1990 through October 1993 were measured by geophysical logging of 3 boreholes located in the alluvium channel of Pagany Wash on Yucca Mountain. The profiles indicated seasonal wetting and drying of the alluvium in response to winter season precipitation and summer season evapotranspiration above a depth of 2.5 meters. A gradual drying trend below a depth of 2.5 meters was interpreted as long-term redistribution and/or evapotranspiration following a deep infiltration event caused by runoff in Pagany Wash during 1984. An initial model, calibrated using the 1990 to 1 992 record, did not provide a satisfactory prediction of water content profiles measured in 1993 following a relatively wet winter season. A re-calibrated model using a modified, seasonally-dependent evapotranspiration function provided an improved fit to the total record. The new model provided a satisfactory verification using water content changes measured at a distance of 6 meters from the calibration site, but was less satisfactory in predicting changes at a distance of 18 meters.

  15. Ground conditions and major construction projects in Singapore, Kuala Lumpur and Jakarta; Singapore Kuala Lumpur Jakarta no jiban to saikin no kensetsu project

    Energy Technology Data Exchange (ETDEWEB)

    Todo, H.; Sagae, T.; Orihara, K.; Yokoi, Y. [Kiso-Jiban Consultants Co. Ltd., Tokyo (Japan)

    1998-01-01

    Geotechnical properties of three major Southeast Asian cities and some construction projects in these cities, are taken up. The soil of Singapore may be roughly divided into four kinds: an Mesozoic intrusive body, sedimentary rock stratum, and Diluvial and Alluvial strata. The use of an empirical formula is in general practice for the calculation of the supporting force of a column. There are certainly some signs of investment in public facilities going downhill. But good signs should also be mentioned, that the construction of a third air terminal, etc., is soon to begin. In the Kuala Lumpur soil, an Upper Paleozoic sedimentary rock and limestone stratum, post-Mesozoic granite stratum, and a Paleozoic basement stratum are distributed and, in the lowland along the rivers, the basement stratum is heavily covered by an alluvium and diluvium The N values are available at many locations. There is a plan for building a new capital but, in this paper, the 450m-tall twin tower Petronas and the new railway system LRT are introduced. Jakarta is situated in a plain 5-10 meters above sea level. The soil consists of an alluvium, Quatanary volcanic rock stratum, and a Tertiary mudstone stratum which constitutes the basement, reckoned from the surface. Regulations, which used to control the construction of buildings with 32 floors or more in the middle of the city, have gone out of effect, and now a number of very tall buildings are under construction. 5 figs.

  16. Geologic framework, regional aquifer properties (1940s-2009), and spring, creek, and seep properties (2009-10) of the upper San Mateo Creek Basin near Mount Taylor, New Mexico

    Science.gov (United States)

    Langman, Jeff B.; Sprague, Jesse E.; Durall, Roger A.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Forest Service, examined the geologic framework, regional aquifer properties, and spring, creek, and seep properties of the upper San Mateo Creek Basin near Mount Taylor, which contains areas proposed for exploratory drilling and possible uranium mining on U.S. Forest Service land. The geologic structure of the region was formed from uplift of the Zuni Mountains during the Laramide Orogeny and the Neogene volcanism associated with the Mount Taylor Volcanic Field. Within this structural context, numerous aquifers are present in various Paleozoic and Mesozoic sedimentary formations and the Quaternary alluvium. The distribution of the aquifers is spatially variable because of the dip of the formations and erosion that produced the current landscape configuration where older formations have been exhumed closer to the Zuni Mountains. Many of the alluvial deposits and formations that contain groundwater likely are hydraulically connected because of the solid-matrix properties, such as substantive porosity, but shale layers such as those found in the Mancos Formation and Chinle Group likely restrict vertical flow. Existing water-level data indicate topologically downgradient flow in the Quaternary alluvium and indiscernible general flow patterns in the lower aquifers. According to previously published material and the geologic structure of the aquifers, the flow direction in the lower aquifers likely is in the opposite direction compared to the alluvium aquifer. Groundwater within the Chinle Group is known to be confined, which may allow upward migration of water into the Morrison Formation; however, confining layers within the Chinle Group likely retard upward leakage. Groundwater was sodium-bicarbonate/sulfate dominant or mixed cation-mixed anion with some calcium/bicarbonate water in the study area. The presence of the reduction/oxidation-sensitive elements iron and manganese in groundwater indicates reducing

  17. A review on anthropogenic impact to the Micro Prespa lake and its damages

    Science.gov (United States)

    Frasheri, N.; Pano, N.; Frasheri, A.; Beqiraj, G.; Bushati, S.; Taska, E.

    2012-04-01

    Paper presents the results of the integrated and multidisciplinary studies for investigation of the anthropogenic damages to Albanian part of the transborder Micro Prespa Lake. Remote sensing with Landsat images was used for identification of environmental changes in time for the period 1970 - 2010. Micro Prespa Lake is lake with international status, as Ramsar Convection, International Park and Special Protection Area-79/409/EEC. According to the studies, investigations and analyses, the following were concluded: Devolli River- Micro Prespa Lake irrigation system was not scientifically supported by environmental engineering, hydroeconomy and International Rights principles. It does work according to the projected parameters, and also, doesn't supply the agricultural needs. About of 10 % of the water volume, discharges by Devolli River in Micro Prespa Lake during the winter, is taken from this lake for the irrigation in summer. Great surface of Albanian part of Micro Prespa Lake is destroyed. The other part of the lake is atrophied and the habitat and biodiversity are damaged. Important and unique species of fish, birds and plants of national and international values are risked. The underground karstic connection ways for water circulation are blocked. There are ruining the historic values of the area, such the encient Treni cave from the Bronze Age. The Albanian part of the Micro Prespa Lake has been damaged by the human activities. A huge amount of 1,2 million cubic meters alluvium has been deposited on the lake bottom and lakeshore, which was transported by the Devolli River waters, since 1974. This river waters, rich in alluvium and organic coal material from outcropped geological formations, also absorbed free chemical toxic remains by the drainage of Devolli farm ground, which have changed the chemical features of the lake water and degrading it. Micro Prespa Lake communicates with Macro Prespa Lake, and together with Ohrid Lake. Blockage of underground

  18. Saturated Zone Colloid-Facilitated Transport

    Energy Technology Data Exchange (ETDEWEB)

    A. Wolfsberg; P. Reimus

    2001-12-18

    The purpose of the Saturated Zone Colloid-Facilitated Transport Analysis and Modeling Report (AMR), as outlined in its Work Direction and Planning Document (CRWMS M&O 1999a), is to provide retardation factors for colloids with irreversibly-attached radionuclides, such as plutonium, in the saturated zone (SZ) between their point of entrance from the unsaturated zone (UZ) and downgradient compliance points. Although it is not exclusive to any particular radionuclide release scenario, this AMR especially addresses those scenarios pertaining to evidence from waste degradation experiments, which indicate that plutonium and perhaps other radionuclides may be irreversibly attached to colloids. This report establishes the requirements and elements of the design of a methodology for calculating colloid transport in the saturated zone at Yucca Mountain. In previous Total Systems Performance Assessment (TSPA) analyses, radionuclide-bearing colloids were assumed to be unretarded in their migration. Field experiments in fractured tuff at Yucca Mountain and in porous media at other sites indicate that colloids may, in fact, experience retardation relative to the mean pore-water velocity, suggesting that contaminants associated with colloids should also experience some retardation. Therefore, this analysis incorporates field data where available and a theoretical framework when site-specific data are not available for estimating plausible ranges of retardation factors in both saturated fractured tuff and saturated alluvium. The distribution of retardation factors for tuff and alluvium are developed in a form consistent with the Performance Assessment (PA) analysis framework for simulating radionuclide transport in the saturated zone. To improve on the work performed so far for the saturated-zone flow and transport modeling, concerted effort has been made in quantifying colloid retardation factors in both fractured tuff and alluvium. The fractured tuff analysis used recent data

  19. A decade of investigations on groundwater arsenic contamination in Middle Ganga Plain, India.

    Science.gov (United States)

    Saha, Dipankar; Sahu, Sudarsan

    2016-04-01

    Groundwater arsenic (As) load in excess of drinking limit (50 µg L(-1)) in the Gangetic Plains was first detected in 2002. Though the menace was known since about two decades from the downstream part of the plains in the Bengal Basin, comprising of Lower Ganga Plain and deltaic plains of Ganga-Brahmaputra-Meghna River system, little thought was given to its possible threat in the upstream parts in the Gangetic Plains beyond Garo-Rajmahal Hills. The contamination in Bengal Basin has become one of the extensively studied issues in the world and regarded as the severest case of health hazard in the history of mankind. The researches and investigations in the Gangetic Plains during the last decade (2003-2013) revealed that the eastern half of the plains, also referred as Middle Ganga Plain (MGP), is particularly affected by contamination, jeopardising the shallow aquifer-based drinking water supply. The present paper reviews researches and investigations carried out so far in MGP by various research institutes and government departments on wide array of issues of groundwater As such as its spatio-temporal variation, mobilisation paths, water level behaviour and flow regime, configuration of contaminated and safe aquifers and their recharge mechanism. Elevated conc. of groundwater As has been observed in grey and dark grey sediments of Holocene age (Newer Alluvium) deposited in a fluvio-lacustrine environment in the floodplain of the Ganga and most of its northern tributaries from Himalayas. Older Alluvium, comprising Pleistocene brownish yellow sediment, extending as deeper aquifers in Newer Alluvium areas, is low in groundwater As. Similarities and differences on issues between the MGP and the Bengal Basin have been discussed. The researches point towards the mobilisation process as reductive dissolution of iron hydroxide coating, rich in adsorbed As, mediated by microbial processes. The area is marked with shallow water level (ground) with ample monsoonal recharge

  20. Landscape-level variation in greenhouse gas emissions in vineyards of central California

    Science.gov (United States)

    Berbeco, M.; Steenwerth, K. L.; Jackson, L. E.; Higgins, C.; Yu, O.; Greenhut, R. F.; O'Geen, T.

    2011-12-01

    Greenhouse gas emissions from agricultural soils can differ greatly across the landscape depending on soil type, landscape formation and management, making the implementation of mitigation practices challenging. In our study, we evaluated the carbon dioxide and nitrous oxide emissions from vineyard soils across a broad landscape in the Lodi Wine-grape District representing three soil types of different geologic history and under varying conventional management systems in the Central Valley of California. Soils of the District vary in space as a result of the depositional history of the parent materials from which the soils formed and subsequent weathering. The nature of the deposition of these materials has resulted in systematic patterns of soils in space. We sampled the following soils from this soil sequence over the larger landscape: 1) Slightly weathered granitic alluvium with low clay content located on the southern side of the district; 2) Intermediately weathered soils derived from granitic alluvium with high clay content located on the northern side of the district; and, 3) Highly weathered soils derived from metavolcanic and metasedimentary alluvium with intermediate clay content and rocky soils located on the eastern side of the district. The climate is Mediterranean with cool, moist winters and hot, dry summers. Initial results indicated that under wet conditions, the soils had similar carbon dioxide emissions with little variation between management or landscape formation. However, carbon dioxide emissions were typically higher in the alley than in the vine row. Nitrous oxide emissions were more variable in the higher clay soils as compared to sandier soils (0-180 g N/ha/day and 0-20 g N/ha/day, respectively). Nitrous oxide emissions were similar from the soil in the alley and vine row. We expect to see similar variability for carbon dioxide emissions under drier conditions later in the summer, but predict that it will differ by landscape position

  1. Soil Properties of Soft Ground Considering Geological Property and Assessment of Liquefaction Hazards using probability concept in Southern Korean Peninsula

    Science.gov (United States)

    Oh, J.; Hwang, J.; Lee, S.; Park, G.; Kim, J.

    2010-12-01

    Soft ground is well known that the most vulnerable to earthquake damage. The main component of the soft ground basically consists of solid minerals, the nature of the soft ground is dependent on the compositions and properties of minerals. However the characteristics of soft soil were treated mainly in terms of engineering, in terms of component materials and geology did not review. In this research, the geological, mineralogical, geochemical and geotechnical characteristics of soft ground in alluvium and coast of the Nakdong River are investigated. And we carry out assessment of the probability of liquefaction induced ground failure (PG) using geological and seismic data. An improved method for evaluation of liquefaction hazard is presented by using the correlation between variables. A well-documented microzonation of the probability of liquefaction induced ground failure prepared for the earthquake disaster was suggested. Study area is classified as alluvial and coastal ground. The former is Quaternary deposits in mid-downstream area of Nakdong river and thickness varies from 10-20m and maximum depth is up to 23.8m. Thickness of Quaternary deposits in the coast area is twice as much as that of alluvium. Units of poorly consolidated, undisturbed gravels, sands, silts and clays are deposited alternately and predominant unit is silt layer. Sediments in all grounds are mainly composed of quartz and feldspars. Illite, kaolinite and vermiculite are occurred as clay minerals and Illite is predominant. Contents of all clay minerals varies from 20~40%. Na content increases as increasing electrical conductivity. pH is within the range of 6-7 in the sediments of alluvium, whereas 7-8.5 range show in the sediments of coast. Value of cone penetration test (CPT) increases as increasing the depth. Distribution of SPT-N value and friction data is similar to that of CPT. Factor of safety (Fs) and calculated probability of liquefaction (PG) are performed using CPT data and

  2. Assessment of planetary geologic mapping techniques for Mars using terrestrial analogs: The SP Mountain area of the San Francisco Volcanic Field, Arizona

    Science.gov (United States)

    Tanaka, K.L.; Skinner, J.A.; Crumpler, L.S.; Dohm, J.M.

    2009-01-01

    We photogeologically mapped the SP Mountain region of the San Francisco Volcanic Field in northern Arizona, USA to evaluate and improve the fidelity of approaches used in geologic mapping of Mars. This test site, which was previously mapped in the field, is chiefly composed of Late Cenozoic cinder cones, lava flows, and alluvium perched on Permian limestone of the Kaibab Formation. Faulting and folding has deformed the older rocks and some of the volcanic materials, and fluvial erosion has carved drainage systems and deposited alluvium. These geologic materials and their formational and modificational histories are similar to those for regions of the Martian surface. We independently prepared four geologic maps using topographic and image data at resolutions that mimic those that are commonly used to map the geology of Mars (where consideration was included for the fact that Martian features such as lava flows are commonly much larger than their terrestrial counterparts). We primarily based our map units and stratigraphic relations on geomorphology, color contrasts, and cross-cutting relationships. Afterward, we compared our results with previously published field-based mapping results, including detailed analyses of the stratigraphy and of the spatial overlap and proximity of the field-based vs. remote-based (photogeologic) map units, contacts, and structures. Results of these analyses provide insights into how to optimize the photogeologic mapping of Mars (and, by extension, other remotely observed planetary surfaces). We recommend the following: (1) photogeologic mapping as an excellent approach to recovering the general geology of a region, along with examination of local, high-resolution datasets to gain insights into the complexity of the geology at outcrop scales; (2) delineating volcanic vents and lava-flow sequences conservatively and understanding that flow abutment and flow overlap are difficult to distinguish in remote data sets; (3) taking care to

  3. A decade of investigations on groundwater arsenic contamination in Middle Ganga Plain, India.

    Science.gov (United States)

    Saha, Dipankar; Sahu, Sudarsan

    2016-04-01

    Groundwater arsenic (As) load in excess of drinking limit (50 µg L(-1)) in the Gangetic Plains was first detected in 2002. Though the menace was known since about two decades from the downstream part of the plains in the Bengal Basin, comprising of Lower Ganga Plain and deltaic plains of Ganga-Brahmaputra-Meghna River system, little thought was given to its possible threat in the upstream parts in the Gangetic Plains beyond Garo-Rajmahal Hills. The contamination in Bengal Basin has become one of the extensively studied issues in the world and regarded as the severest case of health hazard in the history of mankind. The researches and investigations in the Gangetic Plains during the last decade (2003-2013) revealed that the eastern half of the plains, also referred as Middle Ganga Plain (MGP), is particularly affected by contamination, jeopardising the shallow aquifer-based drinking water supply. The present paper reviews researches and investigations carried out so far in MGP by various research institutes and government departments on wide array of issues of groundwater As such as its spatio-temporal variation, mobilisation paths, water level behaviour and flow regime, configuration of contaminated and safe aquifers and their recharge mechanism. Elevated conc. of groundwater As has been observed in grey and dark grey sediments of Holocene age (Newer Alluvium) deposited in a fluvio-lacustrine environment in the floodplain of the Ganga and most of its northern tributaries from Himalayas. Older Alluvium, comprising Pleistocene brownish yellow sediment, extending as deeper aquifers in Newer Alluvium areas, is low in groundwater As. Similarities and differences on issues between the MGP and the Bengal Basin have been discussed. The researches point towards the mobilisation process as reductive dissolution of iron hydroxide coating, rich in adsorbed As, mediated by microbial processes. The area is marked with shallow water level (<8.0 m below ground) with ample

  4. Assessment of heavy metal contamination in soils at Jajmau (Kanpur) and Unnao industrial areas of the Ganga Plain, Uttar Pradesh, India.

    Science.gov (United States)

    Srinivasa Gowd, S; Ramakrishna Reddy, M; Govil, P K

    2010-02-15

    Environmental geochemical studies were carried out in and around Jajmau (Kanpur) and Unnao industrial areas (80 degrees 15'-80 degrees 34'E longitude and 26 degrees 24'-26 degrees 35'N latitude), of Uttar Pradesh to find out the extent of chemical pollution in soil due to industrial waste. Jajmau and Unnao are prominent centers for leather processing clusters of tannery industries (about 450) along the banks of river Ganga, besides other industries. Geologically the study area is beset with alluvium of Quaternary age consisting of older alluvium of middle to upper Pleistocene and newer alluvium of Holocene. The climate of the study area is semi-arid type. Fifty-three soil samples were collected from Jajmau and Unnao industrial areas from top 15 cm layer of the soil and were analyzed for heavy metals by using Philips MagiX PRO-PW 2440 X-ray fluorescence spectrometer. The data reveals that the soil in the area is significantly contaminated with heavy metals such as chromium varies from 161.8 to 6227.8 mg/kg (average of 2652.3mg/kg), Ba varies from 44.1 to 780.9 mg/kg (average of 295.7 mg/kg), Cu varies from 1.7 to 126.1mg/kg (average of 42.9 mg/kg), Pb varies from 10.1 to 67.8 mg/kg (average of 38.3mg/kg), Sr varies from 46.6 to 150.6 mg/kg (average of 105.3mg/kg), V varies from 1.3 to 208.6 mg/kg (average of 54.4 mg/kg) and Zn varies from 43.5 to 687.6 mg/kg (average of 159.9 mg/kg). Soil contamination was assessed on the basis of geoaccumulation index, enrichment factor (EF), contamination factor and degree of contamination. Indiscriminate dumping of hazardous waste in the study area could be the main cause of the soil contamination, spreading by rainwater and wind. Distribution and correlation of heavy metals in soil along with possible remedial measures are discussed. PMID:19837511

  5. Temporal changes in the distribution of /sup 137/Cs in alluvial soils at Los Alamos

    Energy Technology Data Exchange (ETDEWEB)

    Nyhan, J.W.; Hakonson, T.E.; Miera, F.R. Jr.; Bostick, K.V.

    1978-05-01

    The alluvial soils of three liquid-effluent receiving areas at Los Alamos were sampled to determine /sup 137/Cs temporal distributional relationships. Soil radionuclide concentrations were determined as a function of soil depth and distance from the waste outfall, and discussed relative to runoff transport of /sup 137/Cs-contaminated alluvium. The inventories of soil /sup 137/Cs in various segments of each effluent-receiving area were calculated for two sampling periods and compared with amounts of /sup 137/Cs added to the canyons in the liquid wastes. The distribution patterns of soil cesium were compared with the waste-use history of the three study areas and the hydrologic characteristics of the canyons.

  6. A Long-term Reach-Scale Monitoring Network for Riparian Evapotranspiration, Rock Creek, Kansas

    Science.gov (United States)

    Rajaram, H.; Solis, J. A.; Whittemore, D. O.; Butler, J. J.; Reboulet, E.; Knobbe, S.; Dealy, M.

    2011-12-01

    Riparian evapotranspiration (RET) is an important component of basin-wide evapotranspiration (ET), especially in subhumid to semi-arid regions, with significant impact on water management and conservation. In narrow riparian zones, typical of much of the subhumid to semi-arid U.S., direct measurement of RET by eddy correlation is precluded by the limited fetch distance of riparian vegetation. Alternative approaches based on water balance analyses have a long history, but their accuracy is not well understood. Factors such as heterogeneity in soil properties and root distributions, and sparse measurements, introduce uncertainties in RET estimates. As part of a larger effort aimed at improving understanding of basin-wide RET using scaling theories, we installed a continuous monitoring system for water balance estimation at the scale of a single (~100 m long) reach along Rock Creek in the Whitewater Basin in central Kansas. The distinguishing features of this site include a vadose zone with fine-grained soils underlain by a phreatic zone of coarse gravel embedded in clay, overlying karst bedrock. Across the width (~40 m) of the riparian zone, we installed one transect of four wells screened at the bottom of the alluvium (6-7 m depth), each accompanied by a soil moisture profiler with capacitance sensors at 4 vertical levels above the local water-table elevation (~2.5 m depth) and a shallow well screened just below the water table. All wells were instrumented with pressure transducers for monitoring water levels. Additional sets of all sensors were installed at the upstream and downstream ends of the study reach. Initial results from the monitoring network suggest significant complexities in the behavior of the subsurface system at the site, including a high degree of heterogeneity. All deep wells show a rapid response to streamflow variations and nearby pumping. However, the shallow water-table wells do not respond rapidly to either. Both the shallow wells and soil

  7. 230Th/U ages Supporting Hanford Site‐Wide Probabilistic Seismic Hazard Analysis

    Science.gov (United States)

    Paces, James B.

    2014-01-01

    This product represents a USGS Administrative Report that discusses samples and methods used to conduct uranium-series isotope analyses and resulting ages and initial 234U/238U activity ratios of pedogenic cements developed in several different surfaces in the Hanford area middle to late Pleistocene. Samples were collected and dated to provide calibration of soil development in surface deposits that are being used in the Hanford Site-Wide probabilistic seismic hazard analysis conducted by AMEC. The report includes description of sample locations and physical characteristics, sample preparation, chemical processing and mass spectrometry, analytical results, and calculated ages for individual sites. Ages of innermost rinds on a number of samples from five sites in eastern Washington are consistent with a range of minimum depositional ages from 17 ka for cataclysmic flood deposits to greater than 500 ka for alluvium at several sites.

  8. SITE CHARACTERIZATION AND MONITORING DATA FROM THE AREA 5 PILOT WELLS

    Energy Technology Data Exchange (ETDEWEB)

    BECHTEL NEVADA; U.S. DEPARTMENT OF ENERGY, NATIONAL NUCLEAR SECURITY ADMINISTRATION NEVADA SITE OFFICE

    2005-09-01

    Three exploratory boreholes were drilled and completed to the uppermost alluvial aquifer in Area 5 of the Nevada Test Site, Nye County, Nevada, in 1992. The boreholes and associated investigations were part of the Area 5 Site Characterization Program developed to meet data needs associated with regulatory requirements applicable to the disposal of low-level, mixed, and high-specific-activity waste at this site. This series of boreholes was specifically designed to characterize the hydrogeology of the thick vadose zone and to help define the water quality and hydraulic properties of the uppermost aquifer. Wells UE5PW-1, UE5PW-2, and UE5PW-3 are located in a triangular array near the southeast, northeast, and northwest corners, respectively, of the approximately 2.6-square-kilometer Area 5 Radioactive Waste Management Site to give reasonable spatial coverage for sampling and characterization, and to help define the nearly horizontal water table. Two of the wells, UE5PW-1 and UE5PW-2, penetrated only unconsolidated alluvial materials. The third well, located closer to the margin of the basin, penetrated both alluvium and underlying ash-flow and bedded tuff units. The watertable was encountered at the elevation of approximately 734 meters. The results of laboratory testing of core and drill cuttings samples indicate that the mineralogical, material, and hydrologic properties of the alluvium are very similar within and between boreholes. Additional tests on the same core and drill cuttings samples indicate that hydrologic conditions within the alluvium are also similar between pilot wells. Both core and drill cuttings samples are dry (less than 10 percent water content by weight) throughout the entire unsaturated section of alluvium, and water content increases slightly with depth in each borehole. Water potential measurements on core samples show a large positive potential gradient (water tends to move upward, rather than downward) to a depth of approximately 30

  9. Hydrochemical evaluation of groundwater quality in the Çavuşçayı basin, Sungurlu-Çorum, Turkey

    Science.gov (United States)

    Çelik, Mehmet; Yıldırım, Turgut

    2006-06-01

    The purpose of this study is to investigate the quality and usage possibility of groundwater in the Çavuşçayı basin and suggest the best water structure for the groundwater use. Results from hydrochemical analyses reveal that groundwater is mostly affected by salty (Na+ Cl-) waters of the Incik Formation and brackish (Ca2+, Mg2+ SO{4/2-}) waters of the Bayındır Formation. The Alibaba saltpan discharged (2 l/s) from the Incik Formation is used for salt production. In the basin, salinity risk increases with depth and along the groundwater flow direction. Therefore, shallow water and trenches opened in the alluvium aquifer at the east of the basin were determined to yield suitable water with no Na+ and Cl- contamination. Following the heavy rainy period, waters of less salinity and conductivity are possibly used for agriculture.

  10. 230Th/U ages Supporting Hanford Site-Wide Probabilistic Seismic Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Paces, James B. [U.S. Geological Survey

    2014-08-31

    This product represents a USGS Administrative Report that discusses samples and methods used to conduct uranium-series isotope analyses and resulting ages and initial 234U/238U activity ratios of pedogenic cements developed in several different surfaces in the Hanford area middle to late Pleistocene. Samples were collected and dated to provide calibration of soil development in surface deposits that are being used in the Hanford Site-Wide probabilistic seismic hazard analysis conducted by AMEC. The report includes description of sample locations and physical characteristics, sample preparation, chemical processing and mass spectrometry, analytical results, and calculated ages for individual sites. Ages of innermost rinds on a number of samples from five sites in eastern Washington are consistent with a range of minimum depositional ages from 17 ka for cataclysmic flood deposits to greater than 500 ka for alluvium at several sites.

  11. Equation of State for Shock Compression of High Distension Solids

    Science.gov (United States)

    Grady, Dennis

    2013-06-01

    Shock Hugoniot data for full-density and porous compounds of boron carbide, silicon dioxide, tantalum pentoxide, uranium dioxide and playa alluvium are investigated for the purpose of equation-of-state representation of intense shock compression. Complications of multivalued Hugoniot behavior characteristic of highly distended solids are addressed through the application of enthalpy-based equations of state of the form originally proposed by Rice and Walsh in the late 1950's. Additivity of cold and thermal pressure intrinsic to the Mie-Gruneisen EOS framework is replaced by isobaric additive functions of the cold and thermal specific volume components in the enthalpy-based formulation. Additionally, experimental evidence supports acceleration of shock-induced phase transformation on the Hugoniot with increasing levels of initial distention for silicon dioxide, uranium dioxide and possibly boron carbide. Methods for addressing this experimentally observed facet of the shock compression are introduced into the EOS model.

  12. Equation of state for shock compression of distended solids

    Science.gov (United States)

    Grady, Dennis; Fenton, Gregg; Vogler, Tracy

    2014-05-01

    Shock Hugoniot data for full-density and porous compounds of boron carbide, silicon dioxide, tantalum pentoxide, uranium dioxide and playa alluvium are investigated for the purpose of equation-of-state representation of intense shock compression. Complications of multivalued Hugoniot behavior characteristic of highly distended solids are addressed through the application of enthalpy-based equations of state of the form originally proposed by Rice and Walsh in the late 1950's. Additive measures of cold and thermal pressure intrinsic to the Mie-Gruneisen EOS framework is replaced by isobaric additive functions of the cold and thermal specific volume components in the enthalpy-based formulation. Additionally, experimental evidence reveals enhancement of shock-induced phase transformation on the Hugoniot with increasing levels of initial distension for silicon dioxide, uranium dioxide and possibly boron carbide. Methods for addressing this experimentally observed feature of the shock compression are incorporated into the EOS model.

  13. Uranium-series dated authigenic carbonates and Acheulian sites in southern Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, B.J. (Geological Survey, Denver, CO (USA)); McHugh, W.P. (PEIX Inc., Wilkinsburg, PA (USA)); Schaber, G.G.; Breed, C.S. (Geological Survey, Flagstaff, AZ (USA)); Haynes, C.V. (Univ. of Arizona, Tucson (USA))

    1989-02-24

    Field investigations in southern Egypt have yielded Acheulian artifacts in situ in authigenic carbonate deposits (CaCO{sub 3}-cemented alluvium) along the edges of now-aggraded paleovalleys (Wadi Arid and Wadi Safsaf). Uranium-series dating of 25 carbonate samples from various localities as far apart as 70 kilometers indicates that widespread carbonate deposition occurred about 45, 141 and 212 ka (thousand years ago). Most of the carbonate appears to have been precipitated from groundwater, which suggests that these three episodes of deposition may be related to late Pleistocene humid climates that facilitated human settlement in this now hyperarid region. Carbonate cements from sediments containing Acheulian artifacts provide a minimum age of 212 ka for early occupation of the paleovalleys. 16 refs., 3 figs., 2 tabs.

  14. Radioactivity in the underground environment of the Cambric nuclear explosion at the Nevada Test Site

    International Nuclear Information System (INIS)

    The experimental results obtained from investigation of the radionuclide distribution in the environment around the detonation point of the 0.75-kt nuclear test, Cambric, fired 300 m underground in alluvium at the Nevada Test Site in 1965, are presented and discussed. Analyses of sidewall cores obtained ten years later from near ground surface to below the explosion cavity showed that most of the radioactivity is still contained within solid material in the lower cavity region. Water pumped from the region of highest activity at the bottom of the cavity showed only T and 90Sr at levels higher than the recommended concentration guides for drinking water in uncontrolled areas. Recommendations for future studies are given. The investigation is part of the Radionuclide Migration Project sponsored by the Nevada Operations Office of ERDA

  15. Behavior of boundary layer ozone and its precursors over a great alluvial plain of the world: Indo-Gangetic Plains

    Science.gov (United States)

    Beig, G.; Ali, K.

    2006-12-01

    We investigate the special behavior in the distribution of boundary layer ozone and its precursors over world's most extensive tract of uninterrupted alluvium and intensively farmed zones situated in the foothills of Himalayas as major river basin, known as Indo-Gangetic Plains (IGP). The study makes use of a Chemistry-Transport Model forced with dynamical fields and new emission inventories of pollutants established for 2001. It is found that the IGP region is highly vulnerable to human induced pollutant emissions due to conducive synoptic weather pattern which make it a source regions of ozone precursors within which these tracers remain confined and reinforce photochemical production of ozone. In addition, the continental tropical convergence zone and long range transport play a vital role. As a result, elevated levels of ozone concentration (maximum up to 80 ppbv) and its precursors with cellular structure of spatial variation with large seasonality are noticed.

  16. Flood frequency analysis of Ganga river at Haridwar and Garhmukteshwar

    Science.gov (United States)

    Kamal, Vikas; Mukherjee, Saumitra; Singh, P.; Sen, R.; Vishwakarma, C. A.; Sajadi, P.; Asthana, H.; Rena, V.

    2016-02-01

    The Ganga River is a major river of North India and is known for its fertile alluvium deposits formed due to floods throughout the Indo-Gangetic plains. Flood frequency analysis has been carried out through various approaches for the Ganga River by many scientists. With changes in river bed brought out by anthropogenic changes the intensity of flood has also changed in the last decade, which calls for further study. The present study is in a part of the Upper Indo-Ganga plains subzone 1(e). Statistical distributions applied on the discharge data at two stations found that for Haridwar lognormal and for Garhmukteshwar Gumbel EV1 is applicable. The importance of this study lies in its ability to predict the discharge for a return period after a suitable distribution is found for an area.

  17. Model establishments and calibration of degree of saturation influencing the transport of cryptosporidium parvum in lateratic soil in coastal area of Degema

    Directory of Open Access Journals (Sweden)

    Solomon Ndubuisi Eluozo

    2013-03-01

    Full Text Available Calibrating the degree of saturation were to determine the rate at different soil formations, the study   were carried out on Lateratic soil, the degree of saturation were found to establish different rate at different formations, fluctuation in some formation of this contributes to slight degradation of saturation in the study location, but were not predominant, as the influence of alluvium deposited also played its roles on the degree of saturation. The study is imperative because the initial concentrations of this type of contaminants are determined on the rate of saturation; through the formation characteristics, these influence the fast migration of the solute. Finally, the activities of man also played a major role because it allowed for regeneration of the contaminant and this cause fast migration of this type of microbes to groundwater aquifers in the study area.

  18. Questa Baseline and Pre-Mining Ground-Water-Quality Investigation 22 - Ground-Water Budget for the Straight Creek Drainage Basin, Red River Valley, New Mexico

    Science.gov (United States)

    McAda, Douglas P.; Naus, Cheryl A.

    2008-01-01

    either surface-water flow or the component of ground-water flow through fractured bedrock. The inflow to the watershed, calculated to be 701 gallons per minute, is from precipitation. The calculated outflow from the watershed at or upstream from seismic-line 5 (the downstream-most line in Straight Creek prior to entering the Red River Valley) is 540 gallons per minute of evapotranspiration in the watershed upstream from line 5 (77.0 percent of precipitation), 5 gallons per minute of surface-water flow (0.7 percent of precipitation), 122 gallons per minute of ground-water flow through the debris-flow deposits and underlying regolith defined by the seismic data (17.4 percent of precipitation), and 34 gallons per minute of ground-water flow through fractured bedrock below the defined seismic line (4.9 percent of precipitation). The ground-water flow through the alluvium and inter-tonguing debris-flow deposits of the Red River Valley was calculated to be 5,227 gallons per minute at seismic-line 7, the first seismic line in the Red River Valley downstream from Straight Creek. The water budget indicates the amount of ground-water flow that enters the Red River alluvium from the debris-flow deposits and regolith in Straight Creek is small (about 2.3 percent; 122 gallons per minute) compared to the volume of flow that moves through the Red River alluvium. The total amount of ground-water flow from Straight Creek (156 gallons per minute; 122 gallons per minute from debris-flow deposits and regolith plus 34 gallons per minute through fractured bedrock) is about 3.0 percent of the ground-water flow calculated at line 7 for the Red River alluvium.

  19. Blasting side effects - investigations in an opencast coal mine in India

    International Nuclear Information System (INIS)

    Field investigations were conducted in a potential opencast coal mine in India in order to optimise blast patterns for controlling ground vibration, sound pressure level and fly rock within safe and tolerable limits. Blasting was performed in all operating benches (alluvium, sandstone, shale coal) and blast vibrations were monitored on the alluvial soil present in the vicinity of the mine. It was observed that in all the blasting rounds, low frequency ground vibrations were generated. Further investigations were carried out by recording structural response to ground vibration on single and double storied buildings. It was found that the ground vibrations were amplified by structures themselves, as much as 2.0 to 5.6. times. 2 refs., 4 figs., 5 tabs

  20. Soil fungi as indicators of pesticide soil pollution

    Directory of Open Access Journals (Sweden)

    Mandić Leka

    2005-01-01

    Full Text Available Soil fungi, with their pronounced enzymic activity and high osmotic potential, represent a significant indicator of negative effects of different pesticides on the agroecosystem as a whole. In that respect, a trial was set up on the alluvium soil type with the aim to investigate the effect of different herbicides (Simazine, Napropamid, Paraquat, fungicides (Captan and Mancozeb and insecticides (Fenitrothion and Dimethoate on a number of soil fungi under apple trees. The number of soil fungi was determined during four growing seasons by an indirect method of dilution addition on the Czapek agar. The study results indicate that the fungi belong to the group of microorganisms that, after an initial sensible response to the presence of pesticides in the soil, very rapidly establish normal metabolism enabling them even to increase their number. The fungicides and insecticides applied were found to be particularly effective in that respect.

  1. Petrology of tuff units from the J-13 drill site, Jackass Flats, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Heiken, G.H.; Bevier, M.L.

    1979-12-31

    The J-13 drill hole, located in Jackass Flats, Nevada Test Site, has penetrated 125 m of alluvium and 932 m of tuff. Most of the tuff deposits consist of welded tuffs; glass phases in the tuffs have been replaced by authigenic minerals, mainly K-feldspar, silica, and zeolites. The zonation of authigenic minerals, with depth, indictes that alteration of glass phases and filling of vugs occurred during welding and compaction of tuff units soon after deposition and by interaction with groundwater. Zonation of authigenic minerals in tuff deposits at Jackass Flats is similar to mineral zonation in tuffs elsewhere at the Nevada Test Site and in tuff deposits of west Texas. All appear to have been developed by leaching of glass phases and deposition of authigenic minerals in open hydrologic systems. 10 figures, 38 tables.

  2. Spectral variations in rocks and soils containing ferric iron hydroxide and(or) sulfate minerals as seen by AVIRIS and laboratory spectroscopy

    Science.gov (United States)

    Rockwell, Barnaby W.

    2004-01-01

    Analysis of Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data covering the Big Rock Candy Mountain area of the Marysvale volcanic field, west-central Utah, identified abundant rocks and soils bearing jarosite, goethite, and chlorite associated with volcanic rocks altered to propylitic grade during the Miocene (2321 Ma). Propylitically-altered rocks rich in pyrite associated with the relict feeder zones of convecting, shallow hydrothermal systems are currently undergoing supergene oxidation to natrojarosite, kaolinite, and gypsum. Goethite coatings are forming at the expense of jarosite where most pyrite has been consumed through oxidation in alluvium derived from pyrite-bearing zones. Spectral variations in the goethite-bearing rocks that resemble variations found in reference library samples of goethites of varying grain size were observed in the AVIRIS data. Rocks outside of the feeder zones have relatively low pyrite content and are characterized by chlorite, epidote, and calcite, with local copper-bearing quartz-calcite veins. Iron-bearing minerals in these rocks are weathering directly to goethite. Laboratory spectral analyses were applied to samples of iron-bearing rock outcrops and alluvium collected from the area to determine the accuracy of the AVIRIS-based mineral identification. The accuracy of the iron mineral identification results obtained by analysis of the AVIRIS data was confirmed. In general, the AVIRIS analysis results were accurate in identifying medium-grained goethite, coarse-grained goethite, medium- to coarse-grained goethite with trace jarosite, and mixtures of goethite and jarosite. However, rock fragments from alluvial areas identified as thin coatings of goethite with the AVIRIS data were found to consist mainly of medium- to coarse-grained goethite based on spectral characteristics in the visible and near-infrared. To determine if goethite abundance contributed to the spectral variations observed in goethite-bearing rocks

  3. Tertiary and Quaternary Research with Remote Sensing Methods

    Science.gov (United States)

    Conel, J. E.

    1985-01-01

    Problems encountered in mapping the Quaternary section of the Wind River Region using remote sensing methods are discussed. Analysis of the stratigraphic section is a fundamental aspect of the geologic study of sedimentary basins. Stratigraphic analysis of post-Cretaceous rocks in the Wind River Basin encounters problems of a distinctly different character from those involved in studying the pre-Cretaceous section. The interior of the basin is predominantly covered by Tertiary and Quaternary sediments. These rocks, except on the basin margin to the north, are mostly flat lying or gently dipping. The Tertiary section consists of sandstones, siltstones, and tuffaceous sediments, some variegated, but in general poorly bedded and of great lithologic similarity. The Quaternary sediments consist of terrace, fan, and debris tongue deposits, unconsolidated alluvium occupying the bottoms of modern watercourses, deposits of eolian origin and tufa. Terrace and fan deposits are compositionally diverse and reflect the lithologic diversity of the source terranes.

  4. SITE CHARACTERIZATION AND MONITORING DATA FROM THE AREA 5 PILOT WELLS

    International Nuclear Information System (INIS)

    Three exploratory boreholes were drilled and completed to the uppermost alluvial aquifer in Area 5 of the Nevada Test Site, Nye County, Nevada, in 1992. The boreholes and associated investigations were part of the Area 5 Site Characterization Program developed to meet data needs associated with regulatory requirements applicable to the disposal of low-level, mixed, and high-specific-activity waste at this site. This series of boreholes was specifically designed to characterize the hydrogeology of the thick vadose zone and to help define the water quality and hydraulic properties of the uppermost aquifer. Wells UE5PW-1, UE5PW-2, and UE5PW-3 are located in a triangular array near the southeast, northeast, and northwest corners, respectively, of the approximately 2.6-square-kilometer Area 5 Radioactive Waste Management Site to give reasonable spatial coverage for sampling and characterization, and to help define the nearly horizontal water table. Two of the wells, UE5PW-1 and UE5PW-2, penetrated only unconsolidated alluvial materials. The third well, located closer to the margin of the basin, penetrated both alluvium and underlying ash-flow and bedded tuff units. The watertable was encountered at the elevation of approximately 734 meters. The results of laboratory testing of core and drill cuttings samples indicate that the mineralogical, material, and hydrologic properties of the alluvium are very similar within and between boreholes. Additional tests on the same core and drill cuttings samples indicate that hydrologic conditions within the alluvium are also similar between pilot wells. Both core and drill cuttings samples are dry (less than 10 percent water content by weight) throughout the entire unsaturated section of alluvium, and water content increases slightly with depth in each borehole. Water potential measurements on core samples show a large positive potential gradient (water tends to move upward, rather than downward) to a depth of approximately 30

  5. Fens, seasonal wetlands, and the unconfined pumice aquifer east of the Cascade Range, south-central Oregon

    Science.gov (United States)

    Cummings, M. L.; Large, A.; Mowbray, A.; Weatherford, J.; Webb, B.

    2013-12-01

    Fens and seasonal wetlands in the headwaters of the Klamath and Deschutes river basins in south-central Oregon are present in an area blanketed by 2 to 3 m of pumice during the Holocene eruption of Mount Mazama. The lower pumice unit, moderately sorted coarse pumice lapilli to blocks (0.3 to 0.7 cm), phenocrysts, and lithics is 1.5 to 2 m thick; the upper pumice unit, poorly sorted lapilli to blocks (0.2 to 6 cm), minor phenocrysts, and lithics is 1 m thick. Pumice is a perched, unconfined aquifer over low permeability bedrock or pre-eruption fine-grained sediment. Early landscape response included partial erosion of pumice from pre-eruption valleys followed by partial filling by alluvium: phenocryst- and lithic-rich sand grading upward to glassy silt with rounded pumice pebbles. Groundwater-fed wetlands, fens, associated with the unconfined pumice aquifer occur as areas of diffuse groundwater discharge through gently sloping, convex surfaces underlain by up to 1.4 m of peat. Locally, focused discharge through the confining peat layer feeds low discharge streams. Carnivorous plants (sundews and pitcher plants) may be present. The sharp contact between peat and underlying pumice is an erosion surface that cuts progressively deeper into the upper and lower pumice units downslope. At the base of the slope peat with fen discharge feeding surface flow, alluvium with no surface flow, or a subtle berm separating the slope underlain by peat from the valley bottom underlain by alluvium may be present. Distinct vegetation changes take place at this transition. The erosion surface that underlies the peat layer in the fen is at the surface on the opposing valley wall and progressively rises up through the lower and upper pumice units: iron staining and cementation of pumice is locally prominent. Up to 1.5 m difference in water table occurs between the fen and opposing valley wall. Water table in piezometers screened in peat is at the surface. Locally, water table screened in

  6. Ground-water resources of Gregg County, Texas, with a section on Stream runoff

    Science.gov (United States)

    Broadhurst, W.L.; Breeding, S.D.

    1950-01-01

    Field work in the island of St. Croix, V. I., was carried on from December 1938 to April 1939 in connection with a test-drilling program for water sup- plies. The island is 21 miles long and has a maximum width of 6 miles. Its western part consists of a range of mountains flanked on the south by a rolling plain; its narrower eastern part is entirely mountainous. There are only a few small streams. The rolling and fiat lands are cultivated or are in grass, and the mountainous areas are either wooded or in grass. The average rain- fall of the island is 46.34 inches, but severe droughts and periods of excess precipitation are not uncommon. The island is made up of rocks of Upper Cretaceous age, mostly volcanic tufts and limestones known as the Mount Eagle volcanics; diorite intruded into the cretaceous rocks; and Oligocene to Miocene blue clays and yellow marls (the Jealousy formation and Kingshill marl, respectively). Alluvium is widely distributed. The Mount Eagle rocks were strongly folded in early Tertiary time and the Kingshill strata gently folded in post Lower-Miocene time along an east-northeast axis. Three early Tertiary cycles of erosion are recognized. After the folding of the Kingshill marl, streams followed the strike of the folded rocks in a westerly direction, but they gradually assumed southward courses across the marl plain and as a result a western area of old-age topography, a central area of late-mature topography, and an eastern area of early-mature topography have been created. Submerged reefs and emergent reefs and beaches indicate several fairly recent stands of the sea. Water for human consumption is obtained by collecting rain water in cis- terns, but water for other purposes is almost entirely supplied by wells which are generally less than 100 feet deep. Many dug wells are used, but in recent years drilled wells have been constructed. Most of them are discharged by wind-powered pumps of small capacity. Wells are developed in all the rocks

  7. Flood Susceptibility Modeling: A Geo-spatial Technology Multi-criteria Decision Analysis Approach

    Directory of Open Access Journals (Sweden)

    Dano Umar Lawal

    2014-06-01

    Full Text Available Understanding the surface and subsurface condition can immensely enhance the availability of accurate flood susceptibility maps for effective management of flood catastrophe. In this study, remote sensing and Geographic Information System-based (GIS-based Multi-Criteria Decision Analysis (MCDA based on experts’ opinions has been adopted to carry out the preparedness phase of flood management. Establishing a link between the surface/subsurface conditions and flood occurrence is the major objective of this study. The surface/subsurface investigations showed that the lowland areas of the study area are characterized by the presence of flat slope, alluvium deposits and low humid clay soil composition. The GIS-based Analytic Hierarchy Process (AHP model was adopted in simulating the flood susceptible zones map of the study area. Finally, the result revealed that flood generation in the area immensely relied on slope, geology and soil type along with rainfall as the key catalyst.

  8. Environmental influences on the occurrences of sepiolite and palygorskite: a brief review

    Science.gov (United States)

    Jones, Blair F.; Conko, Kathryn M.

    2011-01-01

    Sepiolite is a hydrous magnesium silicate formed by precipitation of near-surface brackish or saline waters, under semi-arid climatic conditions. Four major influences on the distribution of sepiolite are source materials, climate, physical parameters and associated phase relations. Two major pathways governing the occurrence of sepiolite and palygorskite are direct precipitation from solution, and the transformation of precursor phases by dissolution–precipitation. Sepiolite is most commonly found as a result of the former process, whereas palygorskite is often characterized as a product of the latter. Thus, sepiolite typically occurs in lacustrine, often saline, strata, while palygorskite is commonly found in conjunction with soils, alluvium, or most abundantly, calcretes. Here, we review briefly some examples of sepiolite deposits in Spain, Turkey, Argentina, USA, and the African countries of Kenya, Morocco, Tunisia, Senegal, Somalia and South Africa.

  9. Summary of lithologic logging of new and existing boreholes at Yucca Mountain, Nevada, August 1993 to February 1994

    Energy Technology Data Exchange (ETDEWEB)

    Geslin, J.K.; Moyer, T.C.; Buesch, D.C.

    1995-05-01

    Yucca Mountain, Nevada, is being investigated as a potential site for a high-level radioactive waste repository. This report summarizes the lithologic logging of new and existing boreholes at Yucca Mountain that was done from August 1993 to February 1994 by the Rock Characteristics Section, Yucca Mountain Project Branch, US Geological Survey (USGS). Units encountered during logging include Quaternary-Tertiary alluvium/colluvium, Tertiary Rainier Mesa Tuff, all units in the Tertiary Paintbrush Group, Tertiary Calico Hills Formation and Tertiary Prow Pass Tuff. We present criteria used for recognition of stratigraphic contacts, logging results as tables of contact depths for core from neutron (UZN) boreholes and graphical lithologic logs for core from non-UZN boreholes, and descriptions of several distinctive nonwelded tuffs recognized in the PTn hydrogeologic unit of the Paintbrush Group.

  10. The Impact of Hydrodynamics in Erosion - Deposition Process in Can Gio Mangrove Biosphere Reserve, South Viet Nam

    Science.gov (United States)

    Vo-Luong, H. P.

    2014-12-01

    Can Gio Mangrove Biosphere Reserve is always considered as a friendly green belt to protect and bring up the habitants. However, recently some mangrove areas in the Dong Tranh estuary are being eroded seriously. Based on the field measurements in SW and NE monsoons as well as data of topography changes in 10 years, it is proved that hydrodynamics of waves, tidal currents and riverine currents are the main reasons for erosion-deposition processes at the studied site. The erosion-deposition process changes due to monsoon. The analysed results show that high waves and tidal oscillation cause the increase of the erosion rate in NE monsoon. However, high sediment deposition occurs in SW monsoon due to weak waves and more alluvium from upstream. Many young mangrove trees grow up and develop in the SW monsoon. From the research, it is strongly emphasized the role of mangrove forests in soil retention and energy dissipation.

  11. Site Characterization of the Source Physics Experiment Phase II Location Using Seismic Reflection Data

    Science.gov (United States)

    Sexton, E. A.; Snelson, C. M.; Chipman, V.; Emer, D. F.; White, R. L.; Emmitt, R.; Wright, A. A.; Drellack, S.; Huckins-Gang, H.; Mercadante, J.; Floyd, M.; McGowin, C.; Cothrun, C.; Bonal, N.

    2013-12-01

    An objective of the Source Physics Experiment (SPE) is to identify low-yield nuclear explosions from a regional distance. Low-yield nuclear explosions can often be difficult to discriminate among the clutter of natural and man-made explosive events (e.g., earthquakes and mine blasts). The SPE is broken into three phases. Phase I has provided the first of the physics-based data to test the empirical models that have been used to discriminate nuclear events. The Phase I series of tests were placed within a highly fractured granite body. The evolution of the project has led to development of Phase II, to be placed within the opposite end member of geology, an alluvium environment, thereby increasing the database of waveforms to build upon in the discrimination models. Both the granite and alluvium sites have hosted nearby nuclear tests, which provide comparisons for the chemical test data. Phase III of the SPE is yet to be determined. For Phase II of the experiment, characterization of the location is required to develop the geologic/geophysical models for the execution of the experiment. Criteria for the location are alluvium thickness of approximately 170 m and a water table below 170 m; minimal fracturing would be ideal. A P-wave mini-vibroseis survey was conducted at a potential site in alluvium to map out the subsurface geology. The seismic reflection profile consisted of 168 geophone stations, spaced 5 m apart. The mini-vibe was a 7,000-lb peak-force source, starting 57.5 m off the north end of the profile and ending 57.5 m past the southern-most geophone. The length of the profile was 835 m. The source points were placed every 5 m, equally spaced between geophones to reduce clipping. The vibroseis sweep was from 20 Hz down to 180 Hz over 8 seconds, and four sweeps were stacked at each shot location. The shot gathers show high signal-to-noise ratios with clear first arrivals across the entire spread and the suggestion of some shallow reflectors. The data were

  12. Site selection

    International Nuclear Information System (INIS)

    The conditions and criteria for selecting a site for a nuclear weapons test at the Nevada Test Site are summarized. Factors considered are: (1) scheduling of drill rigs, (2) scheduling of site preparation (dirt work, auger hole, surface casing, cementing), (3) schedule of event (when are drill hole data needed), (4) depth range of proposed W.P., (5) geologic structure (faults, Pz contact, etc.), (6) stratigraphy (alluvium, location of Grouse Canyon Tuff, etc.), (7) material properties (particularly montmorillonite and CO2 content), (8) water table depth, (9) potential drilling problems (caving), (10) adjacent collapse craters and chimneys, (11) adjacent expended but uncollapsed sites, (12) adjacent post-shot or other small diameter holes, (13) adjacent stockpile emplacement holes, (14) adjacent planned events (including LANL), (15) projected needs of Test Program for various DOB's and operational separations, and (16) optimal use of NTS real estate

  13. Staying report of Lic. Mirtha Gamba from (Cnea - Argentina) energetic minerals department

    International Nuclear Information System (INIS)

    The visit of the Lic.Gamba to our country, it was oriented to realise a completion of the geochemical sampling by uranium and other elements of interest to clear in lands of the Crystalline basament and the training of the taking of alluvium samples. The tasks were developed so much in cabinet as in field. Besides it were made visits to the laboratories where take place the preparation of samples, chemical analyses and petrography. Also were visited the laboratories of physical analyses in the D.N.T.N (Direction National of Nuclear technology) that it is mounted in DI.NA.MI.GE. And the exit of field was realised to visit two zones worked by the uranium program during years 1985-1987, Valle Chico (Photo-plan Alferez) and Puntas del Mataojo

  14. Arsenic contamination in Bangladesh groundwater: a major environmental and social disaster.

    Science.gov (United States)

    Alam, M G M; Allinson, G; Stagnitti, F; Tanaka, A; Westbrooke, M

    2002-09-01

    In attempting to eliminate disease caused by drinking polluted surface water, millions of shallow surface wells were drilled into the Ganges delta alluvium in Bangladesh. The latest statistics indicate that 80% of Bangladesh and an estimated 40 million people are at risk of arsenic poisoning-related diseases because the ground water in these wells is contaminated with arsenic. The clinical manifestations of arsenic poisoning are myriad, and the correct diagnosis depends largely on awareness of the problem. Patients with melanosis, leuco-melanosis, keratosis, hyperkeratosis, dorsum, non-petting edema, gangrene and skin cancer have been identified. The present article reviews the current arsenic contamination of ground water, hydrological systems, groundwater potential and utilization and environmental pollution in Bangladesh. This paper concludes by clarifying the main actions required to ensure the sustainable development of water resources in Bangladesh.

  15. Caldera collapse: Perspectives from comparing Galápagos volcanoes, nuclear-test sinks, sandbox models, and volcanoes on Mars

    Science.gov (United States)

    Howard, K.A.

    2010-01-01

    The 1968 trapdoor collapse (1.5 km3) of Fernandina caldera in the Galapágos Islands developed the same kinds of structures as found in small sandbox-collapse models and in concentrically zoned sinks formed in desert alluvium by fault subsidence into underground nuclear-explosion cavities. Fernandina’s collapse developed through shear failure in which the roof above the evacuating chamber was lowered mostly intact. This coherent subsidence contrasts to chaotic piecemeal collapse at small, rocky pit craters, underscoring the role of rock strength relative to subsidence size. The zoning at Fernandina implies that the deflated magma chamber underlay a central basin and a bordering inward-dipping monocline, which separates a blind inner reverse fault from an outer zone of normal faulting. Similar concentric zoning patterns can be recognized in coherent subsidence structures ranging over 16 orders of magnitude in size, from sandbox experiments to the giant Olympus Mons caldera on Mars.

  16. Geologic information from satellite images

    Science.gov (United States)

    Lee, K.; Knepper, D. H.; Sawatzky, D. L.

    1974-01-01

    Extracting geologic information from ERTS and Skylab/EREP images is best done by a geologist trained in photo-interpretation. The information is at a regional scale, and three basic types are available: rock and soil, geologic structures, and landforms. Discrimination between alluvium and sedimentary or crystalline bedrock, and between units in thick sedimentary sequences is best, primarily because of topographic expression and vegetation differences. Discrimination between crystalline rock types is poor. Folds and fractures are the best displayed geologic features. They are recognizable by topographic expression, drainage patterns, and rock or vegetation tonal patterns. Landforms are easily discriminated by their familiar shapes and patterns. Several examples demonstrate the applicability of satellite images to tectonic analysis and petroleum and mineral exploration.

  17. Records of wells and springs, water levels, and chemical quality of ground water in the East Portland area, Oregon

    Science.gov (United States)

    Foxworthy, B.L.; Hogenson, G.M.; Hampton, E.R.

    1964-01-01

    Data are presented on more than 300 wells, including many new ones whose records will not be a part of a forthcoming interpretative report on the occurrence of ground water in this area. A brief description of the geomorphic features is given, and the characteristics of the rock units are summarized in a table. Principal aquifers are beds of loose sand and gravel in the early Pliocene Troutdale Formation, late Pleistocene fluviolacustrine deposits, and Recent alluvium. Locally, Columbia River Basalt (Miocene) and the Boring Lava (late Pliocene to Pleistocene) yield substantial amounts of wate.. In addition to well records there are 124 driller's logs and a table of chemical analyses of the ground water.

  18. Newly formed minerals of the Fe-P-S system in Kolyma fulgurite

    Science.gov (United States)

    Plyashkevich, A. A.; Minyuk, P. S.; Subbotnikova, T. V.; Alshevsky, A. V.

    2016-04-01

    Newly obtained data from microscopic, geochemical, and thermomagnetic studies of the large Kolyma fulgurite are presented here: the fulgurite was formed in the Holocene as a result of lightning affected black shale alluvium. The composition is very close to that of glass formed from a melt. The glass has elevated concentrations of Y, Zr, Nb, and REEs. The newly formed mineral phases have been identified: those are Al-Si glass, α-cristobalite, moissanite, native iron with a phosphorus admixture, nickel-less shreibersite (?), troilite, and possibly cohenite. The formation of these minerals is related to the melt fractionation and the effects of element concentration and segregation of ore components under conditions of the rock melting caused by the effect of high-energy plasma (lightning strike).

  19. Hydrogeology, ground-water flow, and tritium movement at low-level radioactive-waste disposal site near Sheffield, Illinois

    Science.gov (United States)

    Garklavs, George; Healy, R.W.

    1986-01-01

    Groundwater flow and tritium movement are described at and near a low-level radioactive waste disposal site near Sheffield, Illinois. Flow in the shallow aquifer is confined to three basins that ultimately drain into a stripmine lake. Most of the flow from the site is through a buried, pebbly sandfilled channel. Remaining flow is toward alluvium of an existing stream. Conceptual flow models for the two largest basins are used to improve definition of flow velocity and direction. Flow velocities range from about 25 to 2,500 ft/yr. Tritium was found in all three basins. The most extensive migration of tritium is coincident with buried channel. Tritium concentrations ranged from detection level to more than 300 nanocuries/L. (USGS)

  20. Petrology of tuff units from the J-13 drill site, Jackass Flats, Nevada

    International Nuclear Information System (INIS)

    The J-13 drill hole, located in Jackass Flats, Nevada Test Site, has penetrated 125 m of alluvium and 932 m of tuff. Most of the tuff deposits consist of welded tuffs; glass phases in the tuffs have been replaced by authigenic minerals, mainly K-feldspar, silica, and zeolites. The zonation of authigenic minerals, with depth, indictes that alteration of glass phases and filling of vugs occurred during welding and compaction of tuff units soon after deposition and by interaction with groundwater. Zonation of authigenic minerals in tuff deposits at Jackass Flats is similar to mineral zonation in tuffs elsewhere at the Nevada Test Site and in tuff deposits of west Texas. All appear to have been developed by leaching of glass phases and deposition of authigenic minerals in open hydrologic systems. 10 figures, 38 tables

  1. Preliminary results of radiation monitoring near uranium mines in Namibia EJOLT Project (DRAFT version)

    Energy Technology Data Exchange (ETDEWEB)

    Chareyron, Bruno

    2012-04-05

    As a part of the EJOLT (Environmental Justice Organizations Liability and Trade) project, EARTHLIFE Namibia and CRIIRAD (Commission for Independent Research and Information about Radiation) have organised visits in areas located in the vicinity of uranium mines in Namibia In the course of an on site mission carried out between September 22 and October 2 2011, scientists from the CRIIRAD laboratory took radiation measurements in situ, and collected 14 samples of top soil, 13 samples of surface sediments of the Swakop, Gawib and Khan rivers, 11 underground water samples in the alluvium of Swakop, and Khan rivers and tap water from Arandis city, and one sample of asparagus. Solid samples have been analysed at the CRIIRAD laboratory in France (measurements performed by HpGe gamma spectrometry) and water samples have been monitored for main chemicals by LDA 26 laboratory in France and for radium 226 and radon 222 at the CRIIRAD laboratory. Some of the preliminary findings are summarised in this report: 1 - The dose rate measured by CRIIRAD on the parking of Roessing mine is about 6 times above natural background value (0.9 {mu}Sv/h compared to 0.15 {mu}Sv/h); 2 - The management of waste rock dumps needs to be improved: Some waste rocks are dumped on the banks of Khan river (at the intersection with Dome Gorge) without fencing and confinement. The radiological impact of this activity has to be studied in detail but preliminary measurements show various impacts on the environment; 3 - The finest fraction of the radioactive tailings dumped on Roessing tailings dam is blown away by the wind and contaminates the surrounding environment; 4 - The high uranium concentration in underground water collected downstream Roessing uranium mine in the Khan river and Swakop river alluvium raises the question of the origin of this uranium

  2. Natural and anthropogenic processes that concentrate Mn in rural and urban environments of the lower Mississippi River delta.

    Science.gov (United States)

    Mielke, H W; Gonzales, C R; Powell, E; Shah, A; Mielke, P W

    2002-10-01

    This study evaluated natural processes and projected methylcyclopentadienyl manganese tricarbonyl fuel additives as sources of Mn accumulation in the environment. Data sets include fresh alluvium and sediments from the lower Mississippi River Delta and a soil metal survey of metropolitan New Orleans. The (1) railroad Mn, (2) industrial Mn, and (3) dynamic aquifer-stream transfer of Mn hypotheses were tested with the Mississippi River Delta data. Friction between Mn-rich steel wheels and rails contributes Mn (P = 0.017) to the environment, supporting (1). Sediment loads of Mn were similar (P = 0.77) upstream and downstream from the Louisiana industrial corridor, not supporting (2). The median Mn on the alluvium surface (59 mg/kg), in the aquifer (159 mg/kg), and in the riverbank aquifer discharge zone (513 mg/kg) support (3) as a mechanism for Mn enrichment of clay. The New Orleans soil metal survey data set shows a rural to urban increase of fourfold for Mn and three orders of magnitude for Pb. At 1999 U.S. highway fuel use, 8.3 mg of Mn per L would yield 5000 metric tons of Mn annually. If 13% of Mn were emitted, 650 tons of Mn would become aerosols annually, while 87% or 4350 tons would remain in engines. The 1999 toxic release inventory for Mn shows 370 tons as total emissions compared to the potential of 390 and 260 tons from vehicles, respectively, in urban and rural areas. A precautionary lesson from the use of Pb as a fuel additive is that the use of Mn as a fuel additive would be associated with an increased risk for neonates exceeding the estimated total tolerable daily intake of 2.1-16.5 micrograms Mn (especially in urban inner city environments) because neonates lack fully functional hepatic clearance for Mn. PMID:12483807

  3. Role of oxbow lakes in controlling redox geochemistry of shallow groundwater under a heterogeneous fluvial sedimentary environment in an agricultural field: Coexistence of iron and sulfate reduction.

    Science.gov (United States)

    Choi, Byoung-Young; Yun, Seong-Taek; Kim, Kyoung-Ho

    2016-01-01

    This study aimed to extend the knowledge of the vertical distribution of redox conditions of shallow groundwater in heterogeneous fluvial sediments near oxbow lakes. For this study, we revisited the study area of Kim et al. (2009) to examine the redox zoning in details. Three multi-level samplers were installed along a flow path near two oxbow lakes to obtain vertical profiles of the subsurface geology and hydrochemical and isotopic data (δ(18)O and δD of water, δ(15)N and δ(18)O of nitrate, and δ(34)S of sulfate) of groundwater. Geologic logging showed that characteristics of the heterogeneous subsurface geology are closely related to the pattern of vertical redox zoning. Hydrochemical data in conjunction with nitrogen and sulfur isotope data show that the redox status of groundwater near oxbow lakes is controlled by denitrification, iron reduction, and sulfate reduction. The oxidizing condition of groundwater occurs in the sand-dominant alluvium located in the up-gradient of oxbow lakes, whereas the reducing condition accompanying denitrification, iron reduction, and local sulfate reduction is developed in silt-rich alluvium in and the downgradient of oxbow lakes. The occurrence of sulfate reduction was newly found in this study. However, the vertical profiles of redox-sensitive parameters show that iron reduction and sulfate reduction occur concurrently near oxbow lakes, although the measured redox potentials suggest that thermodynamic conditions are controlled by the stability of Fe(2+)/Fe-oxides. Therefore, this study shows that the redox condition of groundwater in the iron-rich zone should be carefully interpreted. For this purpose, depth-specific sampling and careful examination of sulfur isotope data will be very useful for identifying the redox processes occurring in the zone with overlapping iron reduction and sulfate reduction in heterogeneous fluvial sediments. PMID:26788873

  4. Characterization and evolution of primary and secondary laterites in northwestern Bengal Basin, West Bengal, India

    Institute of Scientific and Technical Information of China (English)

    Sandipan Ghosh; Sanat K. Guchhait

    2015-01-01

    It is quite impossible to travel far in India without observing the remarkable fer-ruginous crust to which Buchanan in 1807 gave the name of laterite. In Indian peninsula, it is a post-Cretaceous stratigraphic succession with a polycyclic nature of evolution which marks the unconformity with recent Quaternary alluvium. There are perennial problems and research gaps in the investigation of laterites in India as well as in West Bengal:(1) deifning, identify-ing and classifying lateritic materials, (2) mode of formation of laterite and its other horizons, (3) determining the ages of laterites, (4) reliability of laterites as palaeoclimatic indicators, (5) identifying topographic requirements and pedogeomorphic processes for laterite formation, and (6) reconstructions of former lateritized landscapes. The formation of north-south lateritic hard crust (i.e. Rarh Bengal) on the Rajmahal Basalt Traps, Archean granite-gneiss, Gond-wana sediments, Paleogene gravels and older deltaic alluvium is analyzed here to resolve the aforesaid problems and to depict the variable characteristics of laterites with special reference to its tectono-climatic evolution in the northwestern marginal part of Bengal Basin. This paper reveals that the low-level secondary laterites (probably the Pliocene-Early Pleistocene age) of Rarh Bengal are composed of heterogeneous Fe-Al rich gravelly materials which were derived from the high-level primary laterites (probably the Eocene-Miocene age) of plateau since the Paleogene Period by the peninsular river system, following the underlying structure of Bengal Basin. Alongside the roles of drifting of Indian Plate, establishment of monsoon climate, neo-tectonic uplifts and re-lateritization of ferruginous shelf deposits are determined here to unearth the palaeogenesis of primary and secondary laterites in West Bengal.

  5. Use of Borehole Geophysical Logs for Improved Site Characterization at Naval Weapons Industrial Reserve Plant, Dallas, Texas

    Science.gov (United States)

    Anaya, Roberto; Braun, Christopher L.; Kuniansky, Eve L.

    2000-01-01

    A shallow alluvial aquifer at the Naval Weapons Industrial Reserve Plant near Dallas, Texas, has been contaminated by organic solvents used in the fabrication and assembly of aircraft and aircraft parts. Natural gamma-ray and electromagnetic-induction log data collected during 1997 from 162 wells were integrated with existing lithologic and cone-penetrometer test log data to improve characterization of the subsurface alluvium at the site. The alluvium, consisting of mostly fine-grained, low-permeability sediments, was classified into low, intermediate, and high clay-content sediments on the basis of the gamma-ray logs. Low clay-content sediments were interpreted as being relatively permeable, whereas high clay-content sediments were interpreted as being relatively impermeable. Gamma-ray logs, cone-penetrometer test logs, and electromagnetic-induction logs were used to develop a series of intersecting sections to delineate the spatial distribution of low, intermediate, and high clay-content sediments and to delineate zones of potentially contaminated sediments. The sections indicate three major sedimentary units in the shallow alluvial aquifer at NWIRP. The lower unit consists of relatively permeable, low clay-content sediments and is absent over the southeastern and northwestern part of the site. Permeable zones in the complex, discontinuous middle unit are present mostly in the western part of the site. In the eastern and southeastern part of the site, the upper unit has been eroded away and replaced by fill material. Zones of potentially contaminated sediments are generally within the uppermost clay layer or fill material. In addition, the zones tend to be local occurrences.

  6. Disposal configuration options for future uses of greater confinement disposal at the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Price, L. [Science Applications International Corp., Albuquerque, NM (United States)

    1994-09-01

    The US Department of Energy (DOE) is responsible for disposing of a variety of radioactive and mixed wastes, some of which are considered special-case waste because they do not currently have a clear disposal option. The DOE`s Nevada Field Office contracted with Sandia National Laboratories to investigate the possibility of disposing of some of this special-case waste at the Nevada Test Site (NTS). As part of this investigation, a review of a near-surface and subsurface disposal options that was performed to develop alternative disposal configurations for special-case waste disposal at the NTS. The criteria for the review included (1) configurations appropriate for disposal at the NTS; (2) configurations for disposal of waste at least 100 ft below the ground surface; (3) configurations for which equipment and technology currently exist; and (4) configurations that meet the special requirements imposed by the nature of special-case waste. Four options for subsurface disposal of special-case waste are proposed: mined consolidated rock, mined alluvium, deep pits or trenches, and deep boreholes. Six different methods for near-surface disposal are also presented: earth-covered tumuli, above-grade concrete structures, trenches, below-grade concrete structures, shallow boreholes, and hydrofracture. Greater confinement disposal (GCD) in boreholes at least 100 ft deep, similar to that currently practiced at the GCD facility at the Area 5 Radioactive Waste Management Site at the NTS, was retained as the option that met the criteria for the review. Four borehole disposal configurations are proposed with engineered barriers that range from the native alluvium to a combination of gravel and concrete. The configurations identified will be used for system analysis that will be performed to determine the disposal configurations and wastes that may be suitable candidates for disposal of special-case wastes at the NTS.

  7. Groundwater arsenic contamination from parts of the Ghaghara Basin, India: influence of fluvial geomorphology and Quaternary morphostratigraphy

    Science.gov (United States)

    Shah, Babar Ali

    2016-09-01

    A groundwater arsenic (As) distribution in Faizabad, Gonda, and Basti districts of Uttar Pradesh is shown in the entrenched channels and floodplains of the Ghaghara River. Tubewell water samples were analysed for As through flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) system. About 38, 61, and 42 % of tubewells in Faizabad, Gonda, and Basti districts, respectively, have As >10 µg/l (WHO guideline). Moreover, 15, 45, and 26 % of tubewells in Faizabad, Gonda, and Basti districts, respectively, have As above 50 µg/l. About 86, 69, and 35 % of tubewells in Faizabad, Gonda, and Basti districts, respectively, are from shallow depth (21-45 m), and it is worth noticing that 47 % As-contaminated (As >10 µg/l) tubewells in these three districts are located within the depth of 10-35 m in Holocene Newer Alluvium aquifers. The high content of As (7.11 mg/kg) is measured in suspended river sediments of the Ghaghara River. Most of the As-contaminated villages in the Ghaghara Basin are located close to abandoned or present meander channels and floodplains of the Ghaghara River. In contrast, tubewells in Faizabad, Ayodhya, and Nawabganj towns are As-safe because of their positions on the Pleistocene Older Alluvium upland surfaces. Quaternary geomorphology plays an important role in groundwater arsenic contamination in the Ghaghara Basin. The sources of groundwater arsenic are geogenic and perennial mountainous rivers in the Ghaghara Basin supplied high sediment loads. The arsenic in groundwater of Ghaghara Basin is getting released from associated sediments which were likely deposited from the Himalayas. The process of release of groundwater arsenic is reductive dissolution of iron hydroxides.

  8. Kemungkinan sebaran zirkon pada endapan placer di Pulau Kalimantan

    Directory of Open Access Journals (Sweden)

    Danny Zulkifli Herman

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol2no2.20073Most alluvium with valued heavy minerals originated from regions of continental shelf, from which recycle process for stable minerals play an important role in transportation and final concentration formation of the minerals. Kalimantan Island as part of continental shelf has a great opportunity to provide condition or environment for placer deposition with zircon content due to: comprising particularly basement rock of calc-alkali to alkali series (granite, granodiorite, tonalite and monzonite which were suggested as the main supplier sources of zircon; having a long period of regional stability as main contribution in continuation processes of weathering, transportation and forming deposition environment of alluvium and located within a tropical climate with high humidity from which mechanical and chemical weathering processes play an important role in releasing zircon from its source rocks. Continental placer deposit of fluvial sub-environment category is suggested to have possibility to form deposition zone lying between the mountains and the seas, reaching over wide areas and forming huge volume reservoirs with content of zircon. Based on zircon identification (associated with gold or diamond of placer pan concentrates at some areas of West Kalimantan and Central Kalimantan, these have proved how widespread of zircon deposition within fluvial sub-environments in both regions. This important information inspires an opportunity to do exploration of placer zircon deposits within fluvial sub-environments in entirely Kalimantan Island, without neglecting to the transition placer of strandline sub-environment category and marine environment which enable to have an economic deposit of zircon.  

  9. Construction of 3-D geologic framework and textural models for Cuyama Valley groundwater basin, California

    Science.gov (United States)

    Sweetkind, Donald S.; Faunt, Claudia C.; Hanson, Randall T.

    2013-01-01

    Groundwater is the sole source of water supply in Cuyama Valley, a rural agricultural area in Santa Barbara County, California, in the southeasternmost part of the Coast Ranges of California. Continued groundwater withdrawals and associated water-resource management concerns have prompted an evaluation of the hydrogeology and water availability for the Cuyama Valley groundwater basin by the U.S. Geological Survey, in cooperation with the Water Agency Division of the Santa Barbara County Department of Public Works. As a part of the overall groundwater evaluation, this report documents the construction of a digital three-dimensional geologic framework model of the groundwater basin suitable for use within a numerical hydrologic-flow model. The report also includes an analysis of the spatial variability of lithology and grain size, which forms the geologic basis for estimating aquifer hydraulic properties. The geologic framework was constructed as a digital representation of the interpreted geometry and thickness of the principal stratigraphic units within the Cuyama Valley groundwater basin, which include younger alluvium, older alluvium, and the Morales Formation, and underlying consolidated bedrock. The framework model was constructed by creating gridded surfaces representing the altitude of the top of each stratigraphic unit from various input data, including lithologic and electric logs from oil and gas wells and water wells, cross sections, and geologic maps. Sediment grain-size data were analyzed in both two and three dimensions to help define textural variations in the Cuyama Valley groundwater basin and identify areas with similar geologic materials that potentially have fairly uniform hydraulic properties. Sediment grain size was used to construct three-dimensional textural models that employed simple interpolation between drill holes and two-dimensional textural models for each stratigraphic unit that incorporated spatial structure of the textural data.

  10. Dominant geomorphic controls on channel capacity and flood risk in a hydrologically variable fluvial system

    Science.gov (United States)

    Daley, James; Croke, Jacky; Thompson, Chris; Cohen, Tim

    2016-04-01

    Traditionally, particular emphasis has been placed on the hydrological characteristics of rivers to understand the role of channel morphology in flood risk. However, in regions of high hydrological variability, the relationship between channel characteristics and flood conveyance is often highly complex. Consequently in these settings, the applicability of stream discharge or steady-state form-process relationships, may be of less use to understanding flood conveyance. In the subtropical region of southeast Queensland, Australia, rivers are characterized by highly variable flows and entrenched channel morphologies. The latter are such dramatic features, they are termed 'macrochannels'. Following the extreme flood of 2011 in the Lockyer Creek in this region, longitudinal variations in the macrochannel form were found to be a significant factor in flood conveyance. Nine reaches were identified on a basis of flood inundation extent, with significant non-linear changes in channel capacity and discharge, alternating between flood expansion and contraction zones with associated increases and decreases in flood risk. Detailed geomorphic and chronostratigraphic analyses presented here indicate that macrochannel capacity is being strongly influenced by the antecedent bedrock topography, resistant valley-fill and abrupt downstream changes in sediment delivery. A large proportion of the valley fill represents a major Late Pleistocene aggradation phase of fine-grained alluvium that overlies older Pleistocene basal sediments. Subsequent channel incision at 10 ka reoccupied a pre-existing bedrock valley and resistant Pleistocene alluvium imposed substantial controls on the capacity for lateral adjustment. Abrupt changes in sediment supply associated with the location of tributaries provide further evidence for geomorphic controls on macrochannel form and capacity. Identification of the dominant geomorphic factors influencing the overall macrochannel form highlights the relative

  11. Surface slip and off-fault deformation patterns in the 2013 MW 7.7 Balochistan, Pakistan earthquake: Implications for controls on the distribution of near-surface coseismic slip

    Science.gov (United States)

    Zinke, Robert; Hollingsworth, James; Dolan, James F.

    2014-12-01

    of 398 fault offsets measured by visual analysis of WorldView high-resolution satellite imagery with deformation maps produced by COSI-Corr subpixel image correlation of Landsat-8 and SPOT5 imagery reveals significant complexity and distributed deformation along the 2013 Mw 7.7 Balochistan, Pakistan earthquake. Average slip along the main trace of the fault was 4.2 m, with local maximum offsets up to 11.4 m. Comparison of slip measured from offset geomorphic features, which record localized slip along the main strand of the fault, to the total displacement across the entire width of the surface deformation zone from COSI-Corr reveals ˜45% off-fault deformation. While previous studies have shown that the structural maturity of the fault exerts a primary control on the total percentage of off-fault surface deformation, large along-strike variations in the percentage of strain localization observed in the 2013 rupture imply the influence of important secondary controls. One such possible secondary control is the type of near-surface material through which the rupture propagated. We therefore compared the percentage off-fault deformation to the type of material (bedrock, old alluvium, and young alluvium) at the surface and the distance of the fault to the nearest bedrock outcrop (a proxy for sediment thickness along this hybrid strike slip/reverse slip fault). We find significantly more off-fault deformation in younger and/or thicker sediments. Accounting for and predicting such off-fault deformation patterns has important implications for the interpretation of geologic slip rates, especially for their use in probabilistic seismic hazard assessments, the behavior of near-surface materials during coseismic deformation, and the future development of microzonation protocols for the built environment.

  12. Water resources of the Santa Ysabel and Mesa Grande Indian Reservations, San Diego County, California

    Science.gov (United States)

    Freckleton, John R.

    1981-01-01

    The Santa Ysabel (consisting of three tracts) and Mesa Grande Indian Reservations are in north-central San Diego County, Calif. On both reservations fractured and weathered igneous and metamorphic rocks and alluvium are water bearing; however, no wells are known to derive their water entirely from alluvium. Well yields range from 2.5 to 250 gallons per minute. Springs occur where saturated fractured or weathered material intersects the land surface. Spring discharge ranged from 0 gallon per minute (November 1979) to 9.4 gallons per minute (November 1979). Few data are available for the surface water characteristics of the study area. One-time measurements of discharge at selected stream sites were made in late November 1979 and late May 1980; discharges ranged from less than 0.01 cubic foot per second to an estimated 3 cubic feet per second. Further study of the surface-water systems would provide a basis for estimating their development potential. The existing water-supply development on the Santa Ysabel Indian Reservation is adequate for the present residents. The Mesa Grande reservation was unoccupied in 1952, was reportedly unoccupied in November 1979, and has no developed water supply. Additional water can be developed for both reservations from the igneous and metamorphic rock, from presently undeveloped springs, and from perennial reaches of the larger streams. Except for excessive iron and sodium at some ground-water sites and excessive sodium at a few surface-water sites, the water is of suitable quality for domestic and agricultural use. (USGS)

  13. Chemical transport beneath a uranium mill tailings pile, Riverton, Wyoming

    International Nuclear Information System (INIS)

    A detailed geochemical study at the Riverton site was undertaken in order to define the nature of chemical transport between an inactive tailings pile and the relationship between the underlying shallow groundwater system. Isotopic measurements of oxygen, deuterium, and tritium showed that although both the shallow alluvial aquifer and a deeper aquifer in the Wind River Formation were derived from a similar source, the nearby river, recharge from the tailings pile is occurring only in the shallow alluvium. 34S/32S ratios are used as a conservative tracer in defining zones of tailings water contamination. Offsite, drilling has revealed the existence of a chemical plume in which calcium and sulfate concentrations are an order of magnitude or more above background. The plume is also characterized by high dissolved molybdenum concentrations. Pore waters in the tailings exhibit extremely high concentrations of Al, Fe and SO4 and low pH. The dissolution of calcite occurs in the alluvium beneath the pile which is characterized by high partial pressures of CO/sub 2(g)/ in the tailings while serving to neutralize pH. The groundwater, however remains saturated with CaCO3, suggesting that a buffering capacity is active. Beneath and downgradient from the tailings, the groundwater becomes saturated with gypsum. The chemical speciation code, PHREEQE, was used to model mixing reactions, assuming a hydrologically static system. Reaction path simulations were fit to observed trends of pH that were depressed in the contaminated groundwater. The simulations estimate one percent mixing of tailings-pore water with groundwater from the shallow alluvial aquifer

  14. Airborne LiDAR analysis and geochronology of faulted glacial moraines in the Tahoe-Sierra frontal fault zone reveal substantial seismic hazards in the Lake Tahoe region, California-Nevada USA

    Science.gov (United States)

    Howle, James F.; Bawden, Gerald W.; Schweickert, Richard A.; Finkel, Robert C.; Hunter, Lewis E.; Rose, Ronn S.; von Twistern, Brent

    2012-01-01

    We integrated high-resolution bare-earth airborne light detection and ranging (LiDAR) imagery with field observations and modern geochronology to characterize the Tahoe-Sierra frontal fault zone, which forms the neotectonic boundary between the Sierra Nevada and the Basin and Range Province west of Lake Tahoe. The LiDAR imagery clearly delineates active normal faults that have displaced late Pleistocene glacial moraines and Holocene alluvium along 30 km of linear, right-stepping range front of the Tahoe-Sierra frontal fault zone. Herein, we illustrate and describe the tectonic geomorphology of faulted lateral moraines. We have developed new, three-dimensional modeling techniques that utilize the high-resolution LiDAR data to determine tectonic displacements of moraine crests and alluvium. The statistically robust displacement models combined with new ages of the displaced Tioga (20.8 ± 1.4 ka) and Tahoe (69.2 ± 4.8 ka; 73.2 ± 8.7 ka) moraines are used to estimate the minimum vertical separation rate at 17 sites along the Tahoe-Sierra frontal fault zone. Near the northern end of the study area, the minimum vertical separation rate is 1.5 ± 0.4 mm/yr, which represents a two- to threefold increase in estimates of seismic moment for the Lake Tahoe basin. From this study, we conclude that potential earthquake moment magnitudes (Mw) range from 6.3 ± 0.25 to 6.9 ± 0.25. A close spatial association of landslides and active faults suggests that landslides have been seismically triggered. Our study underscores that the Tahoe-Sierra frontal fault zone poses substantial seismic and landslide hazards.

  15. Role of oxbow lakes in controlling redox geochemistry of shallow groundwater under a heterogeneous fluvial sedimentary environment in an agricultural field: Coexistence of iron and sulfate reduction

    Science.gov (United States)

    Choi, Byoung-Young; Yun, Seong-Taek; Kim, Kyoung-Ho

    2016-02-01

    This study aimed to extend the knowledge of the vertical distribution of redox conditions of shallow groundwater in heterogeneous fluvial sediments near oxbow lakes. For this study, we revisited the study area of Kim et al. (2009) to examine the redox zoning in details. Three multi-level samplers were installed along a flow path near two oxbow lakes to obtain vertical profiles of the subsurface geology and hydrochemical and isotopic data (δ18O and δD of water, δ15N and δ18O of nitrate, and δ34S of sulfate) of groundwater. Geologic logging showed that characteristics of the heterogeneous subsurface geology are closely related to the pattern of vertical redox zoning. Hydrochemical data in conjunction with nitrogen and sulfur isotope data show that the redox status of groundwater near oxbow lakes is controlled by denitrification, iron reduction, and sulfate reduction. The oxidizing condition of groundwater occurs in the sand-dominant alluvium located in the up-gradient of oxbow lakes, whereas the reducing condition accompanying denitrification, iron reduction, and local sulfate reduction is developed in silt-rich alluvium in and the downgradient of oxbow lakes. The occurrence of sulfate reduction was newly found in this study. However, the vertical profiles of redox-sensitive parameters show that iron reduction and sulfate reduction occur concurrently near oxbow lakes, although the measured redox potentials suggest that thermodynamic conditions are controlled by the stability of Fe2 +/Fe-oxides. Therefore, this study shows that the redox condition of groundwater in the iron-rich zone should be carefully interpreted. For this purpose, depth-specific sampling and careful examination of sulfur isotope data will be very useful for identifying the redox processes occurring in the zone with overlapping iron reduction and sulfate reduction in heterogeneous fluvial sediments.

  16. Alpha-emitting isotopes and chromium in a coastal California aquifer

    Science.gov (United States)

    Densmore, Jill N.; Izbicki, John A.; Murtaugh, Joseph M.; Swarzenski, Peter W.; Bullen, Thomas D.

    2014-01-01

    The unadjusted 72-h gross alpha activities in water from two wells completed in marine and alluvial deposits in a coastal southern California aquifer 40 km north of San Diego were 15 and 25 picoCuries per liter (pCi/L). Although activities were below the Maximum Contaminant Level (MCL) of 15 pCi/L, when adjusted for uranium activity; there is concern that new wells in the area may exceed MCLs, or that future regulations may limit water use from the wells. Coupled well-bore flow and depth-dependent water-quality data collected from the wells in 2011 (with analyses for isotopes within the uranium, actinium, and thorium decay-chains) show gross alpha activity in marine deposits is associated with decay of naturally-occurring 238U and its daughter 234U. Radon activities in marine deposits were as high as 2230 pCi/L. In contrast, gross alpha activities in overlying alluvium within the Piedra de Lumbre watershed, eroded from the nearby San Onofre Hills, were associated with decay of 232Th, including its daughter 224Ra. Radon activities in alluvium from Piedra de Lumbre of 450 pCi/L were lower than in marine deposits. Chromium VI concentrations in marine deposits were less than the California MCL of 10 μg/L (effective July 1, 2014) but δ53Cr compositions were near zero and within reported ranges for anthropogenic chromium. Alluvial deposits from the nearby Las Flores watershed, which drains a larger area having diverse geology, has low alpha activities and chromium as a result of geologic and geochemical conditions and may be more promising for future water-supply development.

  17. Effect of Reducing Groundwater on the Retardation of Redox-Sensitive Radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q; Zavarin, M; Rose, T P

    2008-04-21

    Laboratory batch sorption experiments were used to investigate variations in the retardation behavior of redox-sensitive radionuclides. Water-rock compositions used during these experiments were designed to simulate subsurface conditions at the Nevada Test Site (NTS), where a suite of radionuclides were deposited as a result of underground nuclear testing. Experimental redox conditions were controlled by varying the oxygen content inside an enclosed glove box and by adding reductants into the testing solutions. Under atmospheric (oxidizing) conditions, the radionuclide distribution coefficients varied with the mineralogical composition of the sorbent and the water chemistry. Under reducing conditions, distribution coefficients showed marked increases for {sup 99}Tc and {sup 237}Np in devitrified tuff, but much smaller variations in alluvium, carbonate rock, and zeolitic tuff. This effect was particularly important for {sup 99}Tc, which tends to be mobile under oxidizing conditions. Unlike other redox-sensitive radionuclides, iodine sorption may decrease under reducing conditions when I{sup -} is the predominant species. Overall, sorption of U to alluvium, devitrified tuff, and zeolitic tuff under atmospheric conditions was less than in the glove-box tests. However, the mildly reducing conditions achieved here were not likely to result in substantial U(VI) reduction to U(IV). Sorption of Pu was not affected by the decreasing redox conditions achieved in this study, as the predominant sorbed Pu species in all conditions was expected to be the low-solubility and strongly sorbing Pu(OH){sub 4}. Depending on the aquifer lithology, the occurrence of reducing conditions along a groundwater flowpath could potentially contribute to the retardation of redox-sensitive radionuclides {sup 99}Tc and {sup 237}Np, which are commonly identified as long-term dose contributors in the risk assessment in various nuclear facilities.

  18. Rain and channel flow supplements to subsurface water beneath hyper-arid ephemeral stream channels

    Science.gov (United States)

    Kampf, Stephanie K.; Faulconer, Joshua; Shaw, Jeremy R.; Sutfin, Nicholas A.; Cooper, David J.

    2016-05-01

    In hyper-arid regions, ephemeral stream channels are important sources of subsurface recharge and water supply for riparian vegetation, but few studies have documented the subsurface water content dynamics of these systems. This study examines ephemeral channels in the hyper-arid western Sonoran Desert, USA to determine how frequently water recharges the alluvial fill and identify variables that affect the depth and persistence of recharge. Precipitation, stream stage, and subsurface water content measurements were collected over a three-year study at six channels with varying contributing areas and thicknesses of alluvial fill. All channels contain coarse alluvium composed primarily of sands and gravels, and some locations also have localized layers of fine sediment at 2-3 m depth. Rain alone contributed 300-400 mm of water input to these channels over three years, but water content responses were only detected for 36% of the rain events at 10 cm depth, indicating that much of the rain water was either quickly evaporated or taken up by plants. Pulses of water from rain events were detected only in the top meter of alluvium. The sites each experienced ⩽5 brief flow events, which caused transient saturation that usually lasted only a few hours longer than flow. These events were the only apparent source of water to depths >1 m, and water from flow events quickly percolated past the deepest measurement depths (0.5-3 m). Sustained saturation in the shallow subsurface only developed where there was a near-surface layer of finer consolidated sediments that impeded deep percolation.

  19. Natural and anthropogenic processes that concentrate Mn in rural and urban environments of the lower Mississippi River Delta

    International Nuclear Information System (INIS)

    This study evaluated natural processes and projected ethyl cyclopentadienyl manganese tricarbonyl fuel additives as sources of Mn accumulation in the environment. Data sets include fresh alluvium and sediments from the lower Mississippi River Delta and a soil metal survey of metropolitan New Orleans. The (1) railroad Mn, (2) industrial Mn, and (3) dynamic aquifer-stream transfer of Mn hypotheses were tested with the Mississippi River Delta data. Friction between Mn-rich steel wheels and rails contributes Mn (P=0.017) to the environment, supporting (1). Sediment loads of Mn were similar (P=0.77) upstream and downstream from the Louisiana industrial corridor, not supporting (2). The median Mn on the alluvium surface (59 mg/kg), in the aquifer (159 mg/kg), and in the riverbank aquifer discharge zone (513 mg/kg) support (3) as a mechanism for Mn enrichment of lay. The New Orleans soil metal survey data set shows a rural to urban increase of fourfold for Mn and three orders of magnitude for Pb. At 1999 .S. highway fuel use, 8.3 mg of Mn per L would yield 5000 metric tons of Mn annually. If 13% of Mn were emitted, 650 tons of Mn would become aerosols annually, while 87% or 4350 tons would remain in engines. The 1999 toxic release inventory for Mn shows 370 tons as total emissions compared to the potential of 390 and 260 tons from vehicles, respectively, in urban and rural areas. A precautionary lesson from the use of Pb as a fuel additive is that the use of Mn as a fuel additive would be associated with an increased risk or neonates exceeding the estimated total tolerable daily intake of .1-16.5μg Mn (especially in urban inner city environments) because neonates lack fully functional hepatic clearance for Mn

  20. Geologic investigation :an update of subsurface geology on Kirtland Air Force Base, New Mexico.

    Energy Technology Data Exchange (ETDEWEB)

    Van Hart, Dirk (GRAM, Inc.)

    2003-06-01

    The objective of this investigation was to generate a revised geologic model of Kirtland Air Force Base (KAFB) incorporating the geological and geophysical data produced since the Site-Wide Hydrogeologic Characterization Project (SWHC) of 1994 and 1995. Although this report has certain stand-alone characteristics, it is intended to complement the previous work and to serve as a status report as of late 2002. In the eastern portion of KAFB (Lurance Canyon and the Hubbell bench), of primary interest is the elevation to which bedrock is buried under a thin cap of alluvium. Elevation maps of the bedrock top reveal the paleodrainage that allows for the interpretation of the area's erosional history. The western portion of KAFB consists of the eastern part of the Albuquerque basin where bedrock is deeply buried under Santa Fe Group alluvium. In this area, the configuration of the down-to-the-west, basin-bounding Sandia and West Sandia faults is of primary interest. New geological and geophysical data and the reinterpretation of old data help to redefine the location and magnitude of these elements. Additional interests in this area are the internal stratigraphy and structure of the Santa Fe Group. Recent data collected from new monitoring wells in the area have led to a geologic characterization of the perched Tijeras Arroyo Groundwater system and have refined the known limits of the Ancestral Rio Grande fluvial sediments within the Santa Fe Group. Both the reinterpretation of the existing data and a review of the regional geology have shown that a segment of the boundary between the eastern and western portions of KAFB is a complicated early Tertiary (Laramide) wrench-fault system, the Tijeras/Explosive Ordnance Disposal Area/Hubbell Spring system. A portion of this fault zone is occupied by a coeval ''pull-apart'' basin filled with early Tertiary conglomerates, whose exposures form the ''Travertine Hills''.

  1. Origen de la casiterita detrítica en los aluviones recientes de Tirados de la Vega-Golpejas (Salamanca

    Directory of Open Access Journals (Sweden)

    Fort González, R.

    1987-04-01

    Full Text Available Two cassiterite anomalies have been detected in the Regato de los Lentiscos and Tirados de la Vega alluviums. in the Golpejas area (Salamanca. The granometric and morphometric parameters of these cassiterites have been compared with those shown by the cassiterite crystal ocurrying in the Golpejas granite. The comparison between the two groups of data allow us to conclude that the anomaly observed in the Regato de los Lentiscos has been originated by the disperssion of the cassiterite from the primary deposit of Golpejas. On the contrary. the anomaly ocuring in the alluviums to the south of Tirados de la Vega shows a different origin, and is coming from stanniferous veins. The factor analysis corroborates the differentiation mentionated aboye. and indicates a migration capacite of about 3 Kms. from the stanniferous deposits of Golpejas for the alluvial cassiterite.En el sector Tirados de la Vega-Golpejas han sido detectadas dos anomalías de casiterita en los aluviones del Regato de los Lentiscos y en otros existentes al sur de Tirados de la Vega. El estudio granométrico y morfométrico de éstas casiteritas. contrastado con el de la casiterita procedente del granito de Golpejas. permite asegurar que la anomalía del Regato de los Lentiscos se debe a la dispersión de la casiterita de aquel granito. mientras que la de Tirados de la Vega procede de filones estanníferos. La aplicación del análisis factoral corrobora este hecho y permite diferenciar las casiteritas que proceden de rocas graníticas de aquellas que vienen de filones estanníferos. Según esto se puede indicar que la capacidad de migración de la casiterita desde el yacimiento estannífero de Golpejas es de unos 3 Kms.

  2. Geology, water-quality, hydrology, and geomechanics of the Cuyama Valley groundwater basin, California, 2008--12

    Science.gov (United States)

    Everett, Rhett; Gibbs, Dennis R.; Hanson, Randall T.; Sweetkind, Donald S.; Brandt, Justin T.; Falk, Sarah E.; Harich, Christopher R.

    2013-01-01

    To assess the water resources of the Cuyama Valley groundwater basin in Santa Barbara County, California, a series of cooperative studies were undertaken by the U.S. Geological Survey and the Santa Barbara County Water Agency. Between 2008 and 2012, geologic, water-quality, hydrologic and geomechanical data were collected from selected sites throughout the Cuyama Valley groundwater basin. Geologic data were collected from three multiple-well groundwater monitoring sites and included lithologic descriptions of the drill cuttings, borehole geophysical logs, temperature logs, as well as bulk density and sonic velocity measurements of whole-core samples. Generalized lithologic characterization from the monitoring sites indicated the water-bearing units in the subsurface consist of unconsolidated to partly consolidated sand, gravel, silt, clay, and occasional cobbles within alluvial fan and stream deposits. Analysis of geophysical logs indicated alternating layers of finer- and coarser-grained material that range from less than 1 foot to more than 20 feet thick. On the basis of the geologic data collected, the principal water-bearing units beneath the monitoring-well sites were found to be composed of younger alluvium of Holocene age, older alluvium of Pleistocene age, and the Tertiary-Quaternary Morales Formation. At all three sites, the contact between the recent fill and younger alluvium is approximately 20 feet below land surface. Water-quality samples were collected from 12 monitoring wells, 27 domestic and supply wells, 2 springs, and 4 surface-water sites and were analyzed for a variety of constituents that differed by site, but, in general, included trace elements; nutrients; dissolved organic carbon; major and minor ions; silica; total dissolved solids; alkalinity; total arsenic and iron; arsenic, chromium, and iron species; and isotopic tracers, including the stable isotopes of hydrogen and oxygen, activities of tritium, and carbon-14 abundance. Of the 39

  3. Geology and ground water in Napa and Sonoma Valleys, Napa and Sonoma Counties, California

    Science.gov (United States)

    Kunkel, Fred; Upson, Joseph Edwin

    1960-01-01

    Napa and Sonoma Valleys are adjacent alluvium-filled valleys about 40 miles northeast of San Francisco. They occupy alined and structurally controlled depressions in the northern Coast Ranges physiographic province and drain south into San Pablo Bay. The valleys are surrounded and underlain by unconsolidated marine and continental sediments and volcanic rocks of Pliocene and Pleistocene age, which are water bearing in large part and together make up relatively extensive ground-water basins. Napa Valley, the eastern valley, is the larger and has a valley-floor area of about 85 square miles. Sonoma Valley has a valley-floor area of about 35 square miles; in addition, about 10 square miles is unreclaimed tidal marsh. The rock units of Napa and Sonoma Valleys are divided into four classes on the basis of their distribution and relative capacity to yield water: (a) Consolidated virtually non-water-bearing chiefly sedimentary (some metamorphic) rocks that range in age from Jurassic ( ?) to Pliocene; (b) marine shale and sand of the Petaluma formation (Pliocene) and the Merced formation (Pliocene and Pleistocene) that do not crop out within Napa or Sonoma Valleys but perhaps are penetrated by some deep wells drilled in Sonoma Valley; (c) Sonoma volcanics of Pliocene age, parts of which are non-water-bearing and parts of which locally yield large quantities of water; and (d) unconsolidated alluvial deposits mainly of Quaternary age. The deposits of classes (c) and (d) contain the most important aquifers in the area. Most of the water used in these valleys is pumped from wells in the younger and older alluvium in the Huichica and Glen Ellen formations. and in the Sonoma volcanics. The principal aquifers are the younger and older alluvium. but appreciable quantities of water are pumped locally from the Sonoma volcanics. The Huichica and Glen Ellen formations yield water in small quantities and at most places supply water only for limited domestic uses. The younger alluvium

  4. Coda Q Attenuation and Source Parameters Analysis in North East India Using Local Earthquakes

    Science.gov (United States)

    Mohapatra, A. K.; Mohanty, W. K.; Earthquake Seismology

    2010-12-01

    Alok Kumar Mohapatra1* and William Kumar Mohanty1 *Corresponding author: alokgpiitkgp@gmail.com 1Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur, West Bengal, India. Pin-721302 ABSTRACT In the present study, the quality factor of coda waves (Qc) and the source parameters has been estimated for the Northeastern India, using the digital data of ten local earthquakes from April 2001 to November 2002. Earthquakes with magnitude range from 3.8 to 4.9 have been taken into account. The time domain coda decay method of a single back scattering model is used to calculate frequency dependent values of Coda Q (Qc) where as, the source parameters like seismic moment(Mo), stress drop, source radius(r), radiant energy(Wo),and strain drop are estimated using displacement amplitude spectrum of body wave using Brune's model. The earthquakes with magnitude range 3.8 to 4.9 have been used for estimation Qc at six central frequencies 1.5 Hz, 3.0 Hz, 6.0 Hz, 9.0 Hz, 12.0 Hz, and 18.0 Hz. In the present work, the Qc value of local earthquakes are estimated to understand the attenuation characteristic, source parameters and tectonic activity of the region. Based on a criteria of homogeneity in the geological characteristics and the constrains imposed by the distribution of available events the study region has been classified into three zones such as the Tibetan Plateau Zone (TPZ), Bengal Alluvium and Arakan-Yuma Zone (BAZ), Shillong Plateau Zone (SPZ). It follows the power law Qc= Qo (f/fo)n where, Qo is the quality factor at the reference frequency (1Hz) fo and n is the frequency parameter which varies from region to region. The mean values of Qc reveals a dependence on frequency, varying from 292.9 at 1.5 Hz to 4880.1 at 18 Hz. Average frequency dependent relationship Qc values obtained of the Northeastern India is 198 f 1.035, while this relationship varies from the region to region such as, Tibetan Plateau Zone (TPZ): Qc= 226 f 1.11, Bengal Alluvium

  5. Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 17. Geomorphology of the Red River Valley, Taos County, New Mexico, and Influence on Ground-Water Flow in the Shallow Alluvial Aquifer

    Science.gov (United States)

    Vincent, Kirk R.

    2008-01-01

    where erosion-resistant bedrock, which tends to form vertical cliffs, restricts the width of the valley bottom. Although the presence of a shallow bedrock sill, overlain by shallow alluvium, is a plausible cause of ground-water emergence, this cause was not demonstrated in the study area. The water-table gradient can locally decrease in the downstream direction because of changes in the hydraulic properties of the alluvium, and this may be a contributing cause of ground-water emergence. However, at one site (near Cabin Springs), ground-water emergence could not be explained by spatial changes in geometric or hydraulic properties of the aquifer. Furthermore, the available evidence demonstrates that ground water flowing through bedrock fractures or colluvium entered the north side of the alluvial aquifer, and is the cause of ground-water emergence. At that location the alluvial aquifer was already flowing full, causing the excess water to emerge into the stream. An indirect consequence of altered rock in the tributary watersheds is the rapid erosion rate of alteration scars combined with the hydraulic properties of sediments shed from those scars. Where alteration scars are large the debris fans at the mouths of the tributary watersheds substantially encroach into the Red River Valley. At such locations debris-fan materials dominate the width and thickness of the alluvium in the valley and reduce the rate of flow of ground water within the Red River alluvial aquifer. Most sites of groundwater emergence are located immediately upstream from or along the margins of debris fans. A substantial fraction of the ground water approaching a debris fan can emerge to become streamflow. This last observation has three implications. First, very little water can flow the entire length of the study area entirely within the alluvial aquifer because the ground water repeatedly contacts debris-fan sediments over that length. Second, it follows that emerging water containing

  6. Ground-water hydrology of the central Raton Basin, Colorado and New Mexico

    Science.gov (United States)

    Geldon, Arthur L.

    1989-01-01

    The watersheds of the Purgatoire and Apishapa Rivers contain most of the public coal lands in the Raton Basin. The U.S. Geological Survey, in cooperation with the U.S. Bureau of Land Management, investigated the hydrogeology of this area from 1978 to 1982, inventorying 231 wells, 38 springs, and 6 mines, and collecting ground-water samples from 71 sites. The Raton Basin is an asymmetrical trough, containing 10,000 to 25,000 feet of sedimentary rocks that range in age from Pennsylvanian to Eocene. These rocks are intruded by Miocene igneous rocks, covered with Pleistocene and Holocene alluvium on pediments and in stream valleys, and underlain by Precambrian crystalline rocks. Bituminous coal occurs in the Vermejo and Raton Formations of Cretaceous and Paleocene age. Virtually all of the sedimentary rocks transmit water. Stream alluvium is the most productive aquifer. Bedrock aquifers have smaller yields but greater distribution. The principal bedrock aquifers are the Cuchara-Poison Canyon and the Raton-Vermejo-Trinidad. Other formations are nearly impermeable or too deep to be utilized economically. The Cuchara-Poison Canyon aquifer provides small, nonsustainable yields to wells. Sandstone and coal layers in the Raton-Vermejo-Trinidad aquifer provide small, sustainable yields, but many of these beds are lenticular and can be missed easily by wells. Water in alluvium typically is less mineralized than in bedrock but more susceptible to contamination. Sodium and calcium bicarbonate waters predominate in the area, but sodium chloride water commonly occurs in the Cuchara-Poison Canyon aquifer and may occur in the Pierre Shale. Plumes of sulfate-enriched water extend from coal mines into bedrock and alluvial aquifers. Dissolved-solids concentrations range from less than 500 milligrams per liter in calcium bicarbonate water to more than 1,500 milligrams per liter in sulfate and chloride waters. Much of the ground water is hard. Nitrogen is enriched in shallow ground water

  7. Natural Barriers of the Geosphere at Yucca Mountain, Nevada

    Science.gov (United States)

    Arlt, H.; Kotra, J.; Mohanty, S.; Winterle, J.

    2005-05-01

    transpiration; effect of surface bedrock characteristics on infiltration; influences of unsaturated zone rocks above the repository on quantity and characteristics of downward flowing water; and the effects of the repository tunnel wall geometry and rock characteristics on seepage into the tunnels. Unsaturated zone rocks below the repository may influence water and radionuclide migration into either fractures or the rock matrix, where processes such as matrix diffusion and sorption can retard radionuclide movement. Properties of different saturated zone rock units may slow the radionuclide flow rate while structural features within the saturated zone rocks (faults, heterogeneities) control water flow rate and direction. The saturated zone alluvium may reduce the water velocity while radionuclides sorption onto the alluvium can further delay radionuclides from reaching the accessible environment.

  8. Geology and mineral deposits of an area in the Departments of Antioquia and Caldas (Subzone IIB), Colombia

    Science.gov (United States)

    Feininger, Tomas; Barrero L., Dario; Castro, Nestor; Hall, R.B.

    1973-01-01

    The Inventario Minero National (IMN), a four-year cooperative geologic mapping and mineral resources appraisal project, was accomplished under an agreement between the Republic of Colombia and the U. S. Agency for International Development from 1964 through 1969. Subzone IIB, consisting essentially of the east half of Zone comprises nearly 20,000 km2 principally in the Department of Antioquia but including also small parts of the Departments of Caldas and Tolima. The rocks in IIB range from Precambrian to Holocene. Precambrian feldspar-quartz gneiss occupies a mosaic of fault-bounded blocks intruded by igneous rocks between the Oto fault and the Rio Magdalena. Paleozoic rocks are extensive, and include lightly metamorphosed graptolite-bearing Ordovician shale at Cristalina, and a major suite of graphitic quartz-mica schist, feldspathic and aluminous gneiss, quartzite, marble, amphibolite, and other rocks. Syntectonic intrusive gneiss included many of the older rocks during a late Paleozoic(?) orogeny, which was accompanied by Abukuma-type metamorphosing from lowermost greenschist to upper amphibolite facies. A Jurassic diorite pluton bounded by faults cuts volcanic rocks of unknown age east of the Otu fault. Cretaceous rocks are major units. Middle Cretaceous carbonaceous shale, sandstone, graywacke, conglomerate, and volcanic rocks are locally prominent. The Antioquian batholith (quartz diorite) of Late Cretaceous age cuts the middle Cretaceous and older rocks. A belt of Tertiary nonmarine clastic sedimentary rocks crops out along the Magdalena Valley. Patches of Tertiary alluvium are locally preserved in the mountains. Quaternary alluvium, much of it auriferous, is widespread in modern stream valleys. Structurally IIB constitutes part of a vast complex synclinorium intruded concordantly by syntectonic catazonal or mesozonal felsic plutons, and by the later epizonal post-tectonic Antioquian batholith. Previously unrecognized major wrench faults are outstanding

  9. Assessing Recharge and Geological Model Uncertainty at the Climax Mine Area of the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    M. Ye; K. Pohlmann; J. Chapman; G. Pohll

    2007-11-08

    Hydrologic analyses are commonly based on a single conceptual-mathematical model. Yet hydrologic environments are open and complex, rendering them prone to multiple interpretations and mathematical descriptions. Considering conceptual model uncertainty is a critical process in hydrologic uncertainty assessment. This study assesses recharge and geologic model uncertainty for the Climax mine area of the Nevada Test Site, Nevada. Five alternative recharge models have been independently developed for Nevada and the Death Valley area of California. These models are (1) the Maxey-Eakin model, (2 and 3) a distributed parameter watershed model with and without a runon-runoff component, and (4 and 5) a chloride mass-balance model with two zero-recharge masks, one for alluvium and one for both alluvium and elevation. Similarly, five geological models have been developed based on different interpretations of available geologic information. One of them was developed by the U.S. Geological Survey for the Death Valley Regional Flow System (DVRFS) model; the other four were developed by Bechtel Nevada for the Yucca Flat Corrective Action Unit (CAU). The Climax mine area is in the northern part of the Yucca Flat CAU, which is within the DVRFS. A total of 25 conceptual models are thus formulated based on the five recharge and five geologic models. The objective of our work is to evaluate the conceptual model uncertainty, and quantify its propagation through the groundwater modeling process. A model averaging method is applied that formally incorporates prior information and field measurements into our evaluation. The DVRFS model developed by the U.S. Geological Survey is used as the modeling framework, into which the 25 models are incorporated. Conceptual model uncertainty is first evaluated through expert elicitation based on prior information possessed by two expert panels. Their perceptions of model plausibility are quantified as prior model probabilities, which are then updated

  10. Late Quaternary landscape evolution in the Great Karoo, South Africa: Processes and drivers.

    Science.gov (United States)

    Oldknow, Chris; Hooke, Janet; Lang, Andreas

    2016-04-01

    The Great Karoo spans the north-central part of South Africa at a major climatic boundary. The characteristics, sequences, spatial patterns and drivers of river response to Late Quaternary climate changes in this region remain unclear due to the fragmentary alluvial/colluvial stratigraphic record and the lack of dated palaeoclimatic archives. Dendritic gully networks incised into deep deposits (up to 6 m) of colluvium and alluvium in the upper Sundays River catchment expose a legacy of "cut and fill" features. In 1st order tributaries, these are predominantly discontinuous palaeochannels and flood-outs with localised palaeosols, whereas in 2nd & 3rd order tributaries there are: 1) incised palaeo-geomorphic surfaces, 2) semi-continuous inset terrace sequences, 3) buried palaeo-gully topography. Using a combination of field mapping, logging of sediment outcrops, soil micromorphological and grain size analysis, mineral magnetic measurements and radiometric dating (OSL & 14C), we derive a stratigraphic evolution model which demonstrates a) the number of phases of incision, aggradation and pedogenesis, b) the spatial and temporal extent of each phase and c) the drivers of alluviation and associated feedbacks. Our reconstruction of regional valley alluviation indicates four distinct terrace units of contrasting depositional age. The base of the succession reflects slow aggradation under periglacial conditions associated with the Last Glacial Maximum. Subsequent channel entrenchment, causing terrace abandonment (T1) occurred in the deglacial period when vegetation and rainfall were in anti-phase. Re-instatement of connectivity with deep upland colluvial stores resulted in the injection of a pulse of sediment to valley floors, triggering compartmentalised backfilling (aggradation of T2) which propagated upstream as far as the second order drainage lines. This backfilling restructured the local hydrology, which, in concert with enhanced summer-rainfall, contributed to a

  11. Identifying flood recharge and inter-aquifer connectivity using multiple isotopes in subtropical Australia

    Directory of Open Access Journals (Sweden)

    A. C. King

    2014-04-01

    Full Text Available An understanding of hydrological processes is vital for the sustainable management of groundwater resources, especially in areas where an aquifer interacts with surface water systems or where aquifer-interconnectivity occurs. This is particularly important in areas that are subjected to frequent drought/flood cycles, such as the Cressbrook Creek catchment in southeast Queensland, Australia. In order to understand the hydrological response to flooding and to identify inter-aquifer connectivity, multiple isotopes (δ2H, δ18O, 87Sr/86Sr, 3H and 14C were used in this study in conjunction with a comprehensive hydrochemical assessment, based on data collected six months after severe flooding in 2011. The depleted stable isotope (δ2H and δ18O signatures of the flood-generating rainfall were evident in surface water samples, indicating that these extreme events were a major source of recharge to the dam in the catchment headlands. Furthermore, stable isotopes confirmed that the flood generated significant recharge to the alluvium in the lower part of the catchment, particularly in areas where interactions between surface waters and groundwater were identified and where diffuse aquifer recharge is normally limited by a thick and relatively impermeable unsaturated zone. However, in the upper parts of the catchment where recharge generally occurs more rapidly due to the dominance of coarse-grained sediments in the unsaturated zone, the stable isotope signature of groundwater resembles the longer-term average rainfall values, highlighting that recharge was sourced from smaller rainfall events that occurred subsequent to the flood. Interactions between the bedrock aquifers and the alluvium were identified at several sites in the lower part of the catchment based on 87Sr/86Sr ratios, and supported by the hydrochemical assessment, which included the modelling of evaporation trends and saturation indices. The integrated approach used in this study

  12. Groundwater-surface water interaction along the Upper Biebrza River, Poland: a spatial-temporal approach with temperature, head and seepage measurements

    Science.gov (United States)

    Anibas, C.; Batelaan, O.; Verbeiren, B.; Buis, K.; Chormanski, J.; de Doncker, L.

    2010-12-01

    The knowledge of mechanisms of interaction of surface and groundwater in the hyporheic zone in rivers is essential for conserving, managing and restoring river adjacent wetlands and its habitats. Reliable estimation of groundwater-surface water exchange challenges hydrological sciences. A promising approach, overcoming limitations of individual methods, is the combination of different methodologies including flux estimates based on thermal measurements, piezometer nests, slug tests and seepage meters. In this contribution such a multi-methodology approach is tested for the Upper Biebrza River, Poland. Time series of thermal profiles are obtained for a period of 9 months. The thermal and physical soil properties show strong spatial and vertical heterogeneities typical for the peat soils of the area. Transient simulations with the numerical 1D heat transport model STRIVE were used to quantify the vertical advective fluxes in the riverbed allowing a first level investigation of groundwater-surface water exchange. The net exchange along the examined section during the 9 month is estimated as a 10.4 mm/d upward flux, which is evaluated as a relatively low intensity of groundwater seepage. Time series of both temperature and hydraulic head gradients were used to calculate hydraulic conductivities and to quantify transient groundwater-surface water exchanges for three locations. They indicated an exchange flux relatively relative stable in time only interrupted by peak values during flood events. Seepage meter measurements provided independent verification results. Interpolating calculated fluxes along the river with GIS techniques resulted in spatially distributed interaction maps. Sections of higher fluxes are statistically correlated to the proximity of the river to the morainic plateaus, which border the river alluvium. In sections where the river is central in the alluvium and relatively far away from the upland low or infiltrating conditions are obtained. This

  13. PAH and metal mixtures in New Orleans soils and sediments.

    Science.gov (United States)

    Mielke, H W; Wang, G; Gonzales, C R; Le, B; Quach, V N; Mielke, P W

    2001-12-17

    The purpose of this study is to determine the degree of PAH contamination and the association of PAHs with inorganic substances in soils and sediments of New Orleans. Bonnet Carré Spillway (BCS) (n = 5) provides modern baseline data, while urban soil samples (CTY) (n = 27) and sediment samples from Bayou St. John (BSJ) (n = 11) provide experimental data for New Orleans. Soil samples were collected from the top 2.5 cm of the surface, air-dried, and sieved (2 mm). Sediments samples were collected with a Wildco-Ekman bottom dredge, air-dried and finely ground. Accelerated solvent extraction (ASE) was used to release PAHs from the samples and analysis was conducted with gas chromatography-mass spectrometry (GC-MS). Metals were extracted using a 5:1 ratio of 1 mol/L nitric acid (room temperature) for soil and sediment samples, shaken for 2 h, centrifuged (1000 x g for 15 min) and filtered. Metal analysis was done by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Mann-Whitney tests show PAH differences (P PAHs is, BSJ sediments (10.3 mg/kg) > CTY soils (3.7 mg/kg) > BCS alluvium (0.28 mg/kg). The sum of the metals are similar for BSJ sediments (698 mg/kg) and CTY soils (679 mg/kg) and significantly lower for BCS (189 mg/kg). Manganese of these samples is similar for each site. For paired samples, Pearson Product Moment Correlation tests reveal that many PAHs are strongly associated with each other at all locations. For BCS alluvium and BSJ sediments, total PAHs are not significantly associated with total metals. For CTY, most pairs of metals are significantly associated, and total soil PAHs are strongly associated with total soil metals (correlation 0.78, P = 4.9 x 10(-4)). The linear model, total soil PAH = 136.3 + 6.25 (total soil metals) forms the basis for a predicted PAH map of New Orleans. Previous empirical research demonstrates an association between soil lead and children's lead exposure. This study indicates that PAHs are part of the soil

  14. Simulation of Seismic Waves from Underground Explosions in Geologic Media: FY2009 Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, A; Vorobiev, O; Sjogreen, B; Petersson, N A

    2009-11-09

    This report summarizes work done after one year on project LL09-Sim-NDD-02 entitled 'Exploratory Research: Advanced Simulation of Low Yield Underground Nuclear Explosions To Improve Seismic Yield Estimation and Source Identification'. Work on this effort proceeded in two thrusts: (1) parametric studies of underground explosion generated motions with GEODYN; and (2) coupling of GEODYN to WPP. GEODYN is a code for modeling hydrodynamic (shock-wave) motions in a wide variety of materials, including earth materials. WPP is an anelastic finite difference code for modeling seismic motions. The sensitivity of seismic motions to emplacement conditions was investigated with a series of parametric studies of low-yield (0.2-4 kiloton) chemical high-explosive shots at a range of burial depths in four canonical geologic media (granite, limestone, tuff and alluvium). Results indicate that the material has a strong impact on the seismic motions consistent with previous reports. Motions computed with GEODYN in realistically complex material models are very consistent with reported motions from nuclear tests by Perret and Bass (1975). The amplitude, frequency content and cavity size resulting from explosions are all strongly sensitive to the material strength. Explosions in high-strength (granite) resulted in the highest amplitude, shortest duration pulse and smallest cavities, whereas explosions in low-strength material (alluvium) resulted in the lowest amplitudes, longest duration pulse and larger cavities. The corner frequencies of P-wave motions at take-off angles corresponding to propagation to teleseismic distances show corresponding behavior, with high-strength materials having the highest corner frequency and low-strength materials having low corner frequency. Gravity has an important effect on the cavity size and outgoing motions due work done against lithostatic stress. In fact without gravity the cavity radius and elastic motions are largely insensitive to

  15. Water supply for the Nuclear Rocket Development Station at the U.S. Atomic Energy Commission's Nevada Test Site

    Science.gov (United States)

    Young, Richard Arden

    1972-01-01

    The Nuclear Rocket Development Station, in Jackass Flats, occupies about 123 square miles in the southwestern part of the U.S. Atomic Energy Commission's Nevada Test Site. Jackass Flats, an intermontane valley bordered by highlands on all sides except for a drainage outlet in the southwestern corner, has an average annual rainfall of 4 inches. Jackass Flats is underlain by alluvium, colluvium, and volcanic rocks of Cenozoic age and, at greater depth, by sedimentary rocks of Paleozoic age. The alluvium and the colluvium lie above the saturated zone throughout nearly all of Jackass Flats. The Paleozoic sedimentary rocks contain limestone and dolomite units that are excellent water producers elsewhere ; however, these units are too deep in Jackass Flats to be economic sources of water. The only important water-producing unit known in the vicinity of the Nuclear Rocket Development Station is a welded-tuff aquifer, the Topopah Spring Member of the Paintbrush Tuff, which receives no significant recharge. This member contains about 500 feet of highly fractured rock underlying an area 11 miles long and 3 miles wide in western Jackass Flats. Permeability of the aquifer is derived mostly from joints and fractures; however, some permeability may be derived from gas bubbles in the upper part of the unit. Transmissivity, obtained from pumping tests, ranges from 68,000 to 488,000 gallons per day per foot. Volume of the saturated part of the aquifer is about 3.5 cubic miles, and the average specific yield probably ranges from 1 to 5 percent. The volume of ground water in storage is probably within the range of 37-187 billion gallons. This large amount of water should be sufficient to supply the needs of the Nuclear Rocket Development Station for many years. Water at the Nuclear Rocket Development Station is used for public supply, construction, test-cell coolant, exhaust cooling, and thermal shielding during nuclear reactor and engine testing, and washdown. Present (1967) average

  16. Sediment Budgets the 'Old Fashioned' way for two Subbasins of the Rio Puerco, Central New Mexico

    Science.gov (United States)

    Pavich, M. J.; Gellis, A. C.; Clark, I.; Ellwein, A. L.; Aby, S.

    2005-12-01

    A sediment budget was constructed for two subbasins of the Rio Puerco watershed, Volcano Hill Wash (9.30 km2) and Arroyo Chavez (2.28 km2), using data collected from 1995 through 1998. The subbasins were selected based on differences in land use. Arroyo Chavez was considered more degraded than Volcano Hill Wash, the latter of which received a grazing management award. The grazing density in the Arroyo Chavez watershed was higher (7.3 animals per 100 hectares) than in the Volcano Hill Wash watershed (1.0 animals per 100 hectares). A gas pipeline and numerous dirt roads are located within the Arroyo Chavez subbasin; neither are present within the Volcano Hill Wash subbasin. The 'old fashioned' sediment budget refers to the approach that was used--determining the total sediment leaving a basin and accounting for that sediment with a variety of field-based, labor intensive techniques. A sediment station with an automatic suspended-sediment sampler was installed at the mouth of each stream to quantify the amount of sediment leaving the subbasins. Upland erosion was measured using erosion pins and sediment traps. Channel erosion was measured using surveyed channel cross sections, bank pins, and scour chains. Aeolian dust deposition was measured with dust traps. Each subbasin was divided into geomorphic surfaces using aerial photographs and field descriptions of soils, slopes, and vegetation cover. In Volcano Hill Wash subbasin, five geomorphic surfaces were delineated: mesa, steep colluvial slopes, alluvium/ colluvium, eolian/alluvium, and the alluvial valley floor. In the Arroyo Chavez subbasin, seven geomorphic surfaces were delineated: mesa, steep colluvial slopes, moderate sloping hillslopes, gently sloping hillslopes, alluvial fans, well-vegetated alluvial valley floor, and a sparsely vegetated alluvial valley floor. Upland erosion and channel erosion rates were summed for each geomorphic surface using a geographical information system (GIS). Results indicate that

  17. Lateral Erosion Encourages Vertical Incision in a Bimodal Alluvial River

    Science.gov (United States)

    Gran, K. B.

    2015-12-01

    Sand can have a strong impact on gravel transport, increasing gravel transport rates by orders of magnitude as sand content increases. Recent experimental work by others indicates that adding sand to an armored bed can even cause armor to break-up and mobilize. These two elements together help explain observations from a bimodal sand and gravel-bedded river, where lateral migration into sand-rich alluvium breaks up the armor layer, encouraging further incision into the bed. Detailed bedload measurements were coupled with surface and subsurface grain size analyses and cross-sectional surveys in a seasonally-incised channel carved into the upper alluvial fan of the Pasig-Potrero River at Mount Pinatubo, Philippines. Pinatubo erupted in 1991, filling valleys draining the flanks of the volcano with primarily sand-sized pyroclastic flow debris. Twenty years after the eruption, sand-rich sediment inputs are strongly seasonal, with most sediment input to the channel during the rainy season. During the dry season, flow condenses from a wide braided planform to a single-thread channel in most of the upper basin, extending several km onto the alluvial fan. This change in planform creates similar unit discharge ranges in summer and winter. Lower sediment loads in the dry season drive vertical incision until the bed is sufficiently armored. Incision proceeds downstream in a wave, with increasing sediment transport rates and decreasing grain size with distance downstream, eventually reaching a gravel-sand transition and return to a braided planform. Incision depths in the gravel-bedded section exceeded 3 meters in parts of a 4 km-long study reach, a depth too great to be explained by predictions from simple winnowing during incision. Instead, lateral migration into sand-rich alluvium provides sufficient fine sediment to break up the armor surface, allowing incision to start anew and increasing the total depth of the seasonally-incised valley. Lateral migration is recorded in a

  18. Discontinuous ephemeral streams

    Science.gov (United States)

    Bull, William B.

    1997-07-01

    ) amount and size of sediment yielded from hillslopes: (2) infiltration capacity of valley-floor alluvium that influences both the unit stream power available for upstream headcut migration, and the attenuation of flashy streamflow events by riparian vegetation in sheetflow reaches; and (3) cohesiveness of alluvium, which affects headcut and streambank morphology, and rates of arroyo extension, downcutting, and widening. Initiation of arroyo cutting may be too complex to be attributed to a single cause such as change in mean annual precipitation or grazing by livestock, but is most likely associated with a decrease in density of protective plant cover on hillsides and along valley floors. Relatively larger unit stream power makes downstream reaches more susceptible to initial entrenchment during floods than headwaters reaches, and favors persistent arroyos. Entrenchment continues until an equilibrium longitudinal profile is briefly attained. Then, channel widening occurs: streambanks are undercut and aggradation begins.

  19. Questa baseline and pre-mining ground-water quality investigation. 21. Hydrology and water balance of the Red River basin, New Mexico 1930-2004

    Science.gov (United States)

    Naus, Cheryl A.; McAda, Douglas P.; Myers, Nathan C.

    2006-01-01

    measured streamflow profiles indicates that, in general, the river is gaining ground water from the alluvium in the reach from the town of Red River to between Hottentot and Straight Creeks, and from Columbine Creek to near Thunder Bridge. The river is losing water to the alluvium from upstream of the mill area to Columbine Creek. Interpretations of ground- and surface-water interactions based on comparisons of mean annual basin yield and measured streamflow are supported further with water-level data from piezometers, wells, and the Red River.

  20. Climate change in southern Illinois, USA, based on the age and δ13C of organic matter in cave sediments

    Science.gov (United States)

    Panno, Samuel V.; Curry, B. Brandon; Wang, Hongfang; Hackley, Keith C.; Liu, Chao-Li; Lundstrom, Craig; Zhou, Juanzuo

    2004-01-01

    Matrix-supported diamicton and uniform to laminated, silty, fine-grained sediment deposited from about 42,500 to 27,600 cal yr B.P. under slackwater conditions nearly filled two caves in southwestern Illinois. At some point, most of the sediment was flushed from the caves and from about 22,700 to 4000 cal yr B.P., floods deposited a drape of sandy and silty sediment on remnant slackwater successions, cobbly alluvium, and bedrock (especially from 7700 to 4000 cal yr B.P.). Clay mineral analyses of the slackwater cave sediment reveal a provenance of chiefly Petersburg Silt, a smectite- and illite-rich proglacial lacustrine unit present in the overlying Illinois Episode glacial succession. Today, remnants of the ancient subterranean slackwater deposits nearly fill several secondary passages and, in at least two locations, cover a cobble-mantled strath terrace 1.3 to 1.5 m above active stream channels. Slumping and sinkhole formation appear to have been important mechanisms for deposition of the ancient subterranean deposits. Slumping of these surficial deposits and associated vegetation can occur along the flanks of sinkholes (in addition to sinkhole formation) and enter caves; however, the finer organics, some of them comminuted during transport into the caves, become part of the cave alluvium. This finer organic fraction is the modern analog of the humified organic matter disseminated in slackwater sediment dated in this investigation by radiocarbon methods. Twenty-four 14C ages on humified organic matter provide chronologic control. The ??13C values of the organic matter reflect the proportion of C4-type to C3-type vegetation growing in and around swallets and sinkholes at the time of redeposition. Drought-tolerant C4-type vegetation was more prevalent relative to C3-type vegetation from 42,500 to 31,200 cal yr B.P. compared to conditions from 28,800 cal yr B.P. to the present. The ??13C values are consistent with the results from other investigations of

  1. Predictive modeling of terrestrial radiation exposure from geologic materials

    Science.gov (United States)

    Haber, Daniel A.

    Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic and natural sources of radioactivity. There is a relationship between radioactivity and geology and in the past this relationship has been used to predict geology from an aerial survey. The purpose of this project is to develop a method to predict the radiologic exposure rate of the geologic materials in an area by creating a model using geologic data, images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), geochemical data, and pre-existing low spatial resolution aerial surveys from the National Uranium Resource Evaluation (NURE) Survey. Using these data, geospatial areas, referred to as background radiation units, homogenous in terms of K, U, and Th are defined and the gamma ray exposure rate is predicted. The prediction is compared to data collected via detailed aerial survey by our partner National Security Technologies, LLC (NSTec), allowing for the refinement of the technique. High resolution radiation exposure rate models have been developed for two study areas in Southern Nevada that include the alluvium on the western shore of Lake Mohave, and Government Wash north of Lake Mead; both of these areas are arid with little soil moisture and vegetation. We determined that by using geologic units to define radiation background units of exposed bedrock and ASTER visualizations to subdivide radiation background units of alluvium, regions of homogeneous geochemistry can be defined allowing for the exposure rate to be predicted. Soil and rock samples have been collected at Government Wash and Lake Mohave as well as a third site near Cameron, Arizona. K, U, and Th concentrations of these samples have been determined using inductively coupled mass spectrometry (ICP-MS) and laboratory counting using radiation detection equipment. In addition, many sample locations also have

  2. Indoor radon concentration: impact of geology in the 2005 Kashmir earthquake-affected Bagh area, Azad Jammu and Kashmir, Pakistan; Concentration de radon interieur: l'impact de la geologie dans la zone Bagh, Azad Jammu et Cachemire, Pakistan affectee par le tremblement de terre de 2005 au Cachemire

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, A.; Khan, S. [Department of Physics, University of Azad Jammu and Kashmir, Muzaffarabad (Pakistan); Baig, M.S. [Institute of Geology, University of Azad Jammu and Kashmir, Muzaffarabad, (Pakistan); Akram, M. [Physics Research Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)

    2011-07-15

    The early Miocene Murree Formation, late Miocene Nagri Formation and recent alluvium rock units are exposed in the sub-Himalayas of the Bagh area, State of Azad Jammu and Kashmir, Pakistan. The Bagh area was badly affected by the Kashmir earthquake of October 8, 2005 which, along the Muzaffarabad Fault, deformed both the hanging and footwall blocks. The cracks, joints, fissures and fractures in houses and bed-rocks might have affected the emission of radon to the surface. Indoor radon concentration measurements were carried out in some dwellings of the Bagh area, Azad Kashmir, Pakistan. The measurements were based on passive integrative detection of radon using CN-85 plastic track detectors in box-type dosimeters. The radon concentration in dwellings was between 50 {+-} 11.6 Bq.m{sup -3} and 167.1 {+-} 21.4 Bq.m{sup -3} with an overall average of 95.1 {+-} 15.8 Bq.m{sup -3} (geometric mean = 93.4 Bq.m{sup -3}). The average radon concentrations in pucka, semi-pucka and kucha houses were 97.6 {+-} 15.4 Bq.m{sup -3}, 89.7 {+-} 15.2 Bq.m{sup -3} and 101.9 {+-} 15.9 Bq.m{sup -3}, respectively. The mean values of radon concentrations in the Nagri Formation, Murree Formation and recent alluvium lithology were 99.3 {+-} 15.8, 90.1 and 96.2 {+-} 15.5 Bq.m{sup -3}, respectively. The annual effective dose to the Bagh population was calculated as 2.38 {+-} 0.77 (1.33 {+-} 0.2 to 4.7 {+-} 0.5) mSv. The average radon (95.1 {+-} 15.8 B m{sup -3}) concentration in dwellings for the inhabitants of the Bagh area was safe from radon-related health hazards and was within the recommended action level (ICRP publication 65 (1993) Protection against radon at home and at work, International Commission on Radiological Protection, Ann. ICRP 23(2)).The indoor radon values obtained in the present study are more than the world average of 40 Bq.m{sup -3} (UNSCEAR (2000) United Nations Scientific Committee on the Effects of Atomic radiation, Report to the General Assembly, United Nations, New

  3. Autogenic incision and terrace formation resulting from abrupt late-glacial base-level fall, lower Chippewa River, Wisconsin, USA

    Science.gov (United States)

    Faulkner, Douglas J.; Larson, Phillip H.; Jol, Harry M.; Running, Garry L.; Loope, Henry M.; Goble, Ronald J.

    2016-08-01

    A paucity of research exists regarding the millennial-scale response of inland alluvial streams to abrupt base-level fall. Studies of modern systems indicate that, over short time scales, the response is a diffusion-like process of upstream-propagating incision. In contrast, evidence from the lower Chippewa River (LCR), located in the upper Midwest of the USA, suggests that autogenic controls operating over time scales of several millennia can overwhelm diffusion, resulting in incision that is prolonged and episodic. During the Last Glacial Maximum, the LCR drained the Chippewa Lobe of the Laurentide Ice Sheet to the glacial upper Mississippi River (UMR). As a meltwater stream, it aggraded and filled its valley with glacial outwash, as did its largest tributaries, which were also meltwater streams. Its nonglacial tributaries aggraded, too, filling their valleys with locally derived sediment. During deglaciation, the UMR incised at least twice, abruptly lowering the LCR's base level - ~ 15 m at 16 ka or earlier and an additional 40 m at ca. 13.4 ka. Each of these base-level falls initiated incision of the LCR, led by upstream migrating knickpoints. The propagation of incision has, however, been a lengthy process. The optically stimulated luminescence (OSL) ages of terrace alluvium indicate that, by 13.5 ka, incision had advanced up the LCR only 15 km, and by 9 ka, only 55 km. The process has also been episodic, resulting in the formation of fill-cut terraces (inferred from GPR surveys and exposures of terrace alluvium) that are younger and more numerous in the upstream direction. Autogenic increases in sediment load and autogenic bed armoring, the result of periodic tributary-stream rejuvenation and preferential winnowing of fines by the incising river, may have periodically caused knickpoint migration and incision to slow and possibly stop, allowing lateral erosion and floodplain formation to dominate. A decline in sediment flux from stabilizing incised tributary

  4. Arsenic contamination in surface drainage and groundwater in part of the southeast Asian tin belt, Nakhon Si Thammarat Province, southern Thailand

    Science.gov (United States)

    Williams, M.; Fordyce, F.; Paijitprapapon, A.; Charoenchaisri, P.

    1996-02-01

    The occurrence of human health problems resulting from arsenic contamination of domestic water supplies in Ron Phibun District, Nakhon Si Thammarat Province, southern Thailand was first recognized in 1987. The area has an extensive history of bedrock and alluvial mining, the waste from which is typically rich in arsenopyrite and related alteration products. In 1994 a collaborative study was instigated involving Thai and British government authorities to establish the distribution and geochemical form of As in surface drainage and aquifer systems in the affected area, the probable sources of As contamination, and the potential for problem alleviation. Hydrochemical analyses of surface- and groundwaters have confirmed the presence of dissolved As at concentrations exceeding WHO potable water guidelines by up to a factor of 500. Contamination of the shallow alluvial aquifer system is systematically more severe than the underlying carbonate-hosted aquifer. Deep boreholes may therefore provide the best available potable water source for the local population. The presence of up to 39% of total As as arsenite (H3AsO3) within the carbonate aquifer may, however, constitute a ‘hidden’ toxicological risk, not evident in the shallow groundwater (in which arsenate species account for > 95% of total As). Mineralogical investigations of As-rich tailings and flotation wastes were undertaken to evaluate their likely impact on water quality. The results indicate that although some flotation wastes contain up to 30% As, the rate of leaching is extremely low. Consequently the As loading of drainage emanating from such waste is below the subregional average. Analyses of the silty alluvium that covers much of the central sector of the study area have highlighted As concentrations of up to 5000 mg kg-1, probably carried by disseminated arsenopyrite. Following sulfide dissolution, the mobility of As in this material may be high (with resultant contamination of shallow groundwater) due

  5. A Unique Laboratory to Explore Soil-Wine Relationships, North Canterbury, New Zealand

    Science.gov (United States)

    Harrison, R.; Tomasino, E.; Tonkin, P.; Webb, T.; Burns, S. F.; Weersing, M.

    2012-12-01

    The special character of North Canterbury is a reflection of its geological history - a region of oblique crustal convergence forming northeast striking folds, creating hill, valley and basin topography. Cretaceous to Tertiary glauconitic sediments, limestones, sandstones and weathered conglomerates overlie basement greywacke sandstones and siltstones. During the late Quaternary, erosion infilled valleys with locally sourced sediments, and basins with greywacke alluvium. Calcareous and noncalcareous loess mantles are locally sourced. Detailed soil mapping of vineyards planted between 1980 and 2000 reveal bedrock and colluvial hill slopes with clayey Haplustolls and Argiustolls, fans with deep silty Hapustalfs and terraces with deep alluvium forming clayey Calciusterts and gravels forming Haplustepts. Definitions of terroir variously include physical attributes such as climate, landscapes, soils and vines, together with cultural traditions represented by grape varieties and systems for canopy management, which come together in particular sensory attributes displayed by certain wines. We have recently begun to explore terroir in the context of New Zealand Pinot Noir (the variety considered by many as most able to communicate details of local geography and site). The assessment of wine sensory attributes is not a trivial task. Our experience is that scale is an important influence as ferment size decreases. We recommend the use of commercially produced wines for such studies. Our work has been carried out using statistically valid designs with expert but untrained panelists. In these circumstances the meaning ascribed to particular attributes may vary between panelists but there is evidence to support the contention that expert panelists tend to share a standard vocabulary and are likely to be familiar with appropriate conceptual models of the wines that allow their differentiation. Our results confirm that Pinot Noir wines from climatically differing regions of New

  6. Mechanical Study on the Exploitation of Groundwater Resources in Crystalline Rocks - Examples of Hoping and Kinmen areas, Taiwan

    Science.gov (United States)

    WU, Z. W.; Yeh, E. C.; Chen, P. C.; Lin, C. K.; Lin, W.; Huang, S. Y.

    2015-12-01

    Intact crystalline rocks of low porosity possess lower water storage. Conversely, fractured crystalline rocks contain higher groundwater resources. Therefore, knowledge of distribution and characteristics of fractures is essential to the exploitation of groundwater resources in crystalline rocks. This research makes crystalline rocks in Hoping and Kinmen areas of Taiwan as examples to integrates previous studies of distribution and attitude of fractures and in-situ stress from surface survey and underground study for estimating the tendencies of slip and dilation of fractures in terms of geomechanics, understanding the characteristics of potential fluid conduits, and benefiting the exploitation and development of groundwater resources. The formations in downstream area of Hoping River contain late Paleozoic to Mesoic meta-granites and marbles, and few alluvium strata. Kinmen island closed to SE Chain is located in Pingtan-Dongshan Metamorphic Belt of Late Yanshan orogeny. The formations contain Mesozoic granite, gneiss, various dikes, and some alluviums. Previous studies had conducted experiments of anelastic strain recovery on retrieved cores in Hoping. The results show that the maximum principal stress is vertical and the horizontal minimum stress is in NE-SW orientation, indicating a normal faulting stress regime with NE-SW extension. Most fractures are in E-W and N-S orientations. Results of hydraulic fracturing experiments in Kinmen display the maximum and intermediate stress is in NW-SE orientation and vertical, respectively, suggesting strike-slip faulting regime with NE-SW extension. Most fractures are in E-W and NE-SW orientations and some are in other orientations. Because of various attitudes and distributions of fractures, origin of fluid conduits is not easy to investigate and predict. Based on in-situ stress data, strikes of predicted fluid conduits in Hoping area is N-S and NW-SE while in Kinmen area is in N-S. Analysis of well logging data and

  7. Hydrochemical processes in a shallow coal seam gas aquifer and its overlying stream–alluvial system: implications for recharge and inter-aquifer connectivity

    International Nuclear Information System (INIS)

    Highlights: • Major ions and isotopes used to study inter-aquifer mixing in a shallow CSG setting. • Considerable heterogeneity in the water composition of the coal-bearing aquifer. • Rapid recharge of the coal-bearing aquifer through highly fractured igneous rocks. • Potential mixing between the coal-bearing aquifer and downstream alluvial aquifer. • Need to consider the seasonal influences on inter-aquifer mixing in CSG settings. - Abstract: In areas of potential coal seam gas (CSG) development, understanding interactions between coal-bearing strata and adjacent aquifers and streams is of highest importance, particularly where CSG formations occur at shallow depth. This study tests a combination of hydrochemical and isotopic tracers to investigate the transient nature of hydrochemical processes, inter-aquifer mixing and recharge in a catchment where the coal-bearing aquifer is in direct contact with the alluvial aquifer and surface drainage network. A strong connection was observed between the main stream and underlying alluvium, marked by a similar evolution from fresh Ca–Mg–HCO3 waters in the headwaters towards brackish Ca–Na–Cl composition near the outlet of the catchment, driven by evaporation and transpiration. In the coal-bearing aquifer, by contrast, considerable site-to-site variations were observed, although waters generally had a Na–HCO3–Cl facies and high residual alkalinity values. Increased salinity was controlled by several coexisting processes, including transpiration by plants, mineral weathering and possibly degradation of coal organic matter. Longer residence times and relatively enriched carbon isotopic signatures of the downstream alluvial waters were suggestive of potential interactions with the shallow coal-bearing aquifer. The examination of temporal variations in deuterium excess enabled detection of rapid recharge of the coal-bearing aquifer through highly fractured igneous rocks, particularly at the catchment

  8. Field Evaluation of Travel Times and Flow Mechanisms in the Mississippi Delta Vadose Zone Using Tracers

    Science.gov (United States)

    Perkins, K. S.; Nimmo, J. R.; Coupe, R. H.; Rose, C. E.; Manning, M. A.

    2008-12-01

    In the Bogue Phalia basin in the Delta region of Mississippi, as in many farmed areas, intensive application of agricultural chemicals has led to their detection in surface and ground water; however, contributing unsaturated zone processes are not well understood. The fine textured soils often exhibit surface ponding and runoff after irrigation and rainfall as well as extensive surface cracking during extended dry periods. Fields are typically land-formed to promote surface flow into irrigation ditches and streams that feed into larger river ecosystems. Downward flow of water below the root zone is considered minimal; regional ground- water models predict only 5 percent or less of precipitation recharges the heavily-used alluvial aquifer. In this study we assessed transport within and below the root zone of a fallow soybean field with a 2-m ring infiltration test including tracers and subsurface instrumentation for sampling and for measuring water content and matric potential. Seven months after tracer application, we collected 47 continuous cores for tracer extraction to define the extent of water movement. Water movement was rapid below the pond, traveling up to 0.21 cm/s, indicating the importance of vertical preferential flow paths. Lateral flow of water at shallow depths was extensive and spatially non uniform, reaching 10 m from the pond within 3 months. Within 2 months, the wetting front reached a textural boundary between the silty soil and sandy alluvium at 5 m. The aquifer was historically confined by the silty material prior to extensive irrigation pumping that has lowered the water table from about 2 m to 12 m. Preliminary results indicate that after 7 months any water breaking through the soil-alluvium boundary, which now acts as a capillary barrier within the vadose zone, likely does so as unstable finger flow (fine-over-coarse layering has been observed in lab studies to initiate fingering) which is difficult to detect with point measurements

  9. Extracting Hydrogeology from Heliborne Dual Moment Transient Electromagnetic Investigations in Geologically Divergent Terrenes

    Science.gov (United States)

    Ahmed, S.; Chandra, S.; Auken, E.; Verma, S. K.

    2015-12-01

    Comprehensive knowledge of aquifer system is an important requisite for its effective management in India. Geological formations are complex and variable, punctual and scarce information are not adequate to understand, asses and manage them. Continuous data acquisition, their interpretation and integration with available geological/geophysical information is the solution. Heliborne dual moment transient electromagnetic (HeliTEM) and magnetic (HeliMAG) measurements have been carried out in divergent geological terrenes in India comprising Gangetic alluvium, Tertiary sediments underlying the Thar desert, Deccan basalts and Gondwana sediments, weathered and fractured granite gneisses and schists and the coastal alluvium with Tertiary sediments. The survey was carried out using state of the art equipment SkyTEM. The paper presents a synopsis of the results of the HeliTEM surveys that have helped in obtaining continuous information on the geoelectrical nature of sub-surface. HeliTEM data were supported by a number of ground geophysical surveys. The results provide the 3D subsurface structures controlling the groundwater conditions, the regional continuity of probable aquifers, the variations in lithological character and the quality of water in terms of salinity. Specialized features pertaining to hydrogeological characteristics obtained from this study are as follows: A clear delineation of clay beds and their spatial distribution providing the multi-layered aquifer setup in the Gangetic plains. Delineation of low resistivity zones in the quartzite below the over exploited aquifers indicating the possibility of new aquifers. Presence of freshwater zones underneath the saline water aquifers in the thick and dry sands in deserts. Clear demarcation of different lava flows, mapping the structural controls and highly porous zones in the contact of basalts and Gondwanas. A complete and continuous mapping of weathered zone in crystalline hard rock areas providing information

  10. Effect of reducing groundwater on the retardation of redox-sensitive radionuclides

    Directory of Open Access Journals (Sweden)

    Rose TP

    2008-12-01

    Full Text Available Abstract Laboratory batch sorption experiments were used to investigate variations in the retardation behavior of redox-sensitive radionuclides. Water-rock compositions were designed to simulate subsurface conditions at the Nevada Test Site (NTS, where a suite of radionuclides were deposited as a result of underground nuclear testing. Experimental redox conditions were controlled by varying the oxygen content inside an enclosed glove box and by adding reductants into the testing solutions. Under atmospheric (oxidizing conditions, radionuclide distribution coefficients varied with the mineralogic composition of the sorbent and the water chemistry. Under reducing conditions, distribution coefficients showed marked increases for 99Tc (from 1.22 at oxidizing to 378 mL/g at mildly reducing conditions and 237Np (an increase from 4.6 to 930 mL/g in devitrified tuff, but much smaller variations in alluvium, carbonate rock, and zeolitic tuff. This effect was particularly important for 99Tc, which tends to be mobile under oxidizing conditions. A review of the literature suggests that iodine sorption should decrease under reducing conditions when I- is the predominant species; this was not consistently observed in batch tests. Overall, sorption of U to alluvium, devitrified tuff, and zeolitic tuff under atmospheric conditions was less than in the glove-box tests. However, the mildly reducing conditions achieved here were not likely to result in substantial U(VI reduction to U(IV. Sorption of Pu was not affected by the decreasing Eh conditions achieved in this study, as the predominant sorbed Pu species in all conditions was expected to be the low-solubility and strongly sorbing Pu(OH4. Depending on the aquifer lithology, the occurrence of reducing conditions along a groundwater flowpath could potentially contribute to the retardation of redox-sensitive radionuclides 99Tc and 237Np, which are commonly identified as long-term dose contributors in the risk

  11. Improved estimates show large circumpolar stocks of permafrost carbon while quantifying substantial uncertainty ranges and identifying remaining data gaps

    Directory of Open Access Journals (Sweden)

    G. Hugelius

    2014-03-01

    Full Text Available Soils and other unconsolidated deposits in the northern circumpolar permafrost region store large amounts of soil organic carbon (SOC. This SOC is potentially vulnerable to remobilization following soil warming and permafrost thaw, but stock estimates are poorly constrained and quantitative error estimates were lacking. This study presents revised estimates of the permafrost SOC pool, including quantitative uncertainty estimates, in the 0–3 m depth range in soils as well as for deeper sediments (>3 m in deltaic deposits of major rivers and in the Yedoma region of Siberia and Alaska. The revised estimates are based on significantly larger databases compared to previous studies. Compared to previous studies, the number of individual sites/pedons has increased by a factor ×8–11 for soils in the 1–3 m depth range,, a factor ×8 for deltaic alluvium and a factor ×5 for Yedoma region deposits. Upscaled based on regional soil maps, estimated permafrost region SOC stocks are 217 ± 15 and 472 ± 34 Pg for the 0–0.3 m and 0–1 m soil depths, respectively (±95% confidence intervals. Depending on the regional subdivision used to upscale 1–3 m soils (following physiography or continents, estimated 0–3 m SOC storage is 1034 ± 183 Pg or 1104 ± 133 Pg. Of this, 34 ± 16 Pg C is stored in thin soils of the High Arctic. Based on generalised calculations, storage of SOC in deep deltaic alluvium (>3 m to ≤60 m depth of major Arctic rivers is estimated to 91 ± 39 Pg (of which 69 ± 34 Pg is in permafrost. In the Yedoma region, estimated >3 m SOC stocks are 178 +140/−146 Pg, of which 74 +54/−57 Pg is stored in intact, frozen Yedoma (late Pleistocene ice- and organic-rich silty sediments with the remainder in refrozen thermokarst deposits (±16/84th percentiles of bootstrapped estimates. A total estimated mean storage for the permafrost region of ca. 1300–1370 Pg with an uncertainty range of 930–1690 Pg encompasses the combined revised

  12. Geochemical and C, O, Sr, and U-series isotopic evidence for the meteoric origin of calcrete at Solitario Wash, Crater Flat, Nevada, USA

    Science.gov (United States)

    Neymark, L. A.; Paces, J. B.; Marshall, B. D.; Peterman, Z. E.; Whelan, J. F.

    2005-08-01

    Calcite-rich soils (calcrete) in alluvium and colluvium at Solitario Wash, Crater Flat, Nevada, USA, contain pedogenic calcite and opaline silica similar to soils present elsewhere in the semi-arid southwestern United States. Nevertheless, a ground-water discharge origin for the Solitario Wash soil deposits was proposed in a series of publications proposing elevation-dependent variations of carbon and oxygen isotopes in calcrete samples. Discharge of ground water in the past would raise the possibility of future flooding in the unsaturated zone at Yucca Mountain, Nevada, site of a proposed high-level nuclear waste repository. New geochemical and carbon, oxygen, strontium, and uranium-series isotopic data disprove the presence of systematic elevation-isotopic composition relations, which are the main justification given for a proposed ground-water discharge origin of the calcrete deposits at Solitario Wash. Values of δ13C (-4.1 to -7.8 per mil [‰]), δ18O (23.8-17.2‰), 87Sr/86Sr (0.71270-0.71146), and initial 234U/238U activity ratios of about 1.6 in the new calcrete samples are within ranges previously observed in pedogenic carbonate deposits at Yucca Mountain and are incompatible with a ground-water origin for the calcrete. Variations in carbon and oxygen isotopes in Solitario Wash calcrete likely are caused by pedogenic deposition from meteoric water under varying Quaternary climatic conditions over hundreds of thousands of years.

  13. San Ignacio (La Tembladera) geothermal site, Departamento de Francisco Morazan, Honduras, Central America: Geological field report

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, M.J.; Eppler, D.; Heiken, G.; Flores, W.; Ramos, N.; Ritchie, A.

    1987-06-01

    The San Ignacio (La Tembladera) geothermal site is located on the north side of the Siria Valley, Departamento de Francisco Morazan, near the village of Barrosa. Hot springs are located along a northwest-trending fault scarp at the edge of the valley and along north-trending faults that cross the scarp. The rocks in the area are primarily Paleozoic metamorphic rocks, overlain by patches of Tertiary Padre Miguel Group tuffs and alluvial deposits. Movement probably occurred along several faults during latest Tertiary and possibly early Quaternary times. Four spring areas were mapped. Area 1, the largest, is associated with a sinter mound and consists of 40 spring groups. About half of the springs, aligned along a north-south trend, are boiling. Area 2 is a small sinter mound with several seeps. Area 3 consists of a group of hot and boiling springs aligned along a north-trending fault. The springs rise through fractured schists and a thin cover of alluvium. Area 4 is located at the intersection of several faults and includes one of the largest boiling springs in the area.

  14. Impact of surface coal mining and reclamation on the hydrogeology at Iowa Coal Project Demonstration Mine No. 1, Mahaska County, Iowa. [MS thesis

    Energy Technology Data Exchange (ETDEWEB)

    Stangl, D.W.

    1979-07-01

    The groundwater effects of surface mining at ICP No. 1 can be classified primarily as water quality and water quantity effects. The water quantity effects are: the loss of groundwater saturation in spoil materials that were initially removed from over the coal and later replaced; the dewatering of high permeability geologic strata up gradient of mining area; the increase in porosity and possibly permeability in refilled spoil materials; and the change in groundwater gradients in mined areas and near the sediment pond. The water quality effects are: the generation of slightly mineralized enclaves near the sediment pond and spoil accumulations; the generation of thin zones of highly mineralized water near the base of reclaimed spoil probably due mostly to remnant acid mine water; and reduction of water quality in coal seams as a result of dewatering at the time of mining and subsequent oxidation of their pyrite content. Most effects of water quantity loss in and around the mine are not permanent. Water quality disturbances of the fringe areas of reclaimed mine areas will be very slow in attenuating because of the slow groundwater flow through these materials. Adulterated groundwaters in high permeability areas such as the flood plain alluvium will be more quickly attenuated than those in the mine spoil areas, but these enclaves also have the potential to effect much larger areas due to more rapid groundwater movement. Reduced pH and alkalinity were observed in very restricted areas near the east side of the sediment pond.

  15. Co-occurrence of arsenic and fluoride in groundwater of semi-arid regions in Latin America: genesis, mobility and remediation.

    Science.gov (United States)

    Alarcón-Herrera, María Teresa; Bundschuh, Jochen; Nath, Bibhash; Nicolli, Hugo B; Gutierrez, Melida; Reyes-Gomez, Victor M; Nuñez, Daniel; Martín-Dominguez, Ignacio R; Sracek, Ondra

    2013-11-15

    Several million people around the world are currently exposed to excessive amounts of arsenic (As) and fluoride (F) in their drinking water. Although the individual toxic effects of As and F have been analyzed, there are few studies addressing their co-occurrences and water treatment options. Several studies conducted in arid and semi-arid regions of Latin America show that the co-occurrences of As and F in drinking water are linked to the volcaniclastic particles in the loess or alluvium, alkaline pH, and limited recharge. The As and F contamination results from water-rock interactions and may be accelerated by geothermal and mining activities, as well as by aquifer over-exploitation. These types of contamination are particularly pronounced in arid and semi-arid regions, where high As concentrations often show a direct relationship with high F concentrations. Enrichment of F is generally related to fluorite dissolution and it is also associated with high Cl, Br, and V concentrations. The methods of As and F removal, such as chemical precipitation followed by filtration and reverse osmosis, are currently being used at different scales and scenarios in Latin America. Although such technologies are available in Latin America, it is still urgent to develop technologies and methods capable of monitoring and removing both of these contaminants simultaneously from drinking water, with a particular focus towards small-scale rural operations.

  16. Groundwater Budget Analysis of Cross Formational Flow: Hueco Bolson (Texas and Chihuahua)

    Science.gov (United States)

    Hutchison, W. R.

    2005-12-01

    Groundwater from the Hueco Bolson supplies the majority of municipal water in El Paso, Texas and Ciudad Juarez, Chihuahua, the largest international border community in the world. For over 100 years, water managers and researchers have been developing an understanding of Hueco Bolson groundwater occurrence and movement, and the interaction between surface water and groundwater. Since 2001, isotopic studies of groundwater chemistry on both sides of the border have provided valuable insights into the occurrence of groundwater and its historic movement. Numerical groundwater flow models of the area have been developed and used since the 1970s. The results of the most recent model were used to develop a detailed analysis of the groundwater inflows, outflows and storage change of the entire area and subregions of the model domain from 1903 to 2002. These detailed groundwater budgets were used to quantify temporal and spatial flow changes that resulted from groundwater pumping: induced inflow of surface water, decreased natural outflows, and storage declines. In addition, the detailed groundwater budgets were used to quantify the changes in cross formational flow between the Rio Grande Alluvium and the Hueco Bolson, as well as the changes in vertical flow within the Hueco Bolson. The groundwater budget results are consistent with the results of the isotopic analyses, providing a much needed confirmation of the overall conceptual model of the numerical model. In addition, the groundwater budgets have provided information that has been useful in further interpreting the results of the isotopic analyses.

  17. Hotel Pegaso - Georgetown - Guayana Británica

    Directory of Open Access Journals (Sweden)

    Taylor Woodrow, International Ltd., Arquitectos

    1973-09-01

    Full Text Available The hotel is made up of a basement and a nine-storey high circular tower. In the first, the common use premises have been arranged, whereas the tower contains the bed-rooms and private apartments. A central service nucleus houses: staircases, lifts and vertical air conditioning ducts. It is built of a metal structure and concrete slabs for the floors. The partition walls dividing the bedrooms in the tower are arranged radially. For the foundations, box-type piles were used, filled with concrete, due to the soft alluvium soil on which the town stands.El hotel está constituido por un basamento y una torre circular de nueve plantas de altura. En el primero se han dispuesto los locales de uso común, mientras que la torre contiene los dormitorios y apartamentos privados. Un núcleo central, de servicio, alberga: las escaleras, los ascensores y los conductos verticales del aire acondicionado. Su construcción es a base de estructura metálica y losas de hormigón para los suelos. Los tabiques que delimitan los dormitorios de la torre van dispuestos de manera radial. Para la cimentación se utilizaron pilotes, tipo cajón, rellenos de hormigón, a causa de los blandos terrenos de aluvión sobre los que se asienta la ciudad.

  18. Status of the ground water flow model for the UMTRA Project, Shiprock, New Mexico, site

    International Nuclear Information System (INIS)

    A two-dimensional numerical model was constructed for the alluvial aquifer in the area of the Uranium Mill Tailings Remedial Action (UMTRA) Project Shiprock, New Mexico, site. This model was used to investigate the effects of various hydrologic parameters on the evolution of the ground water flow field. Results of the model are useful for defining uncertainties in the site conceptual model and suggesting data collection efforts to reduce these uncertainties. The computer code MODFLOW was used to simulate the two-dimensional flow of ground water in the alluvium. The escarpment was represented as a no-flow boundary. The San Juan River was represented with the MODFLOW river package. A uniform hydraulic conductivity distribution with the value estimated by the UMTRA Project Technical Assistance Contractor (TAC) and a uniform recharge distribution was used. Infiltration from the flowing artesian well was represented using the well package. The ground water flow model was calibrated to ground water levels observed in April 1993. Inspection of hydrographs shows that these levels are representative of typical conditions at the site

  19. Completion Report for Well ER-2-1

    Energy Technology Data Exchange (ETDEWEB)

    Bechtel Nevada

    2004-10-01

    Well ER-2-1 was drilled for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (formerly Nevada Operations Office), in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. This well was drilled in February and March of 2003, as part of a hydrogeologic investigation program for the Yucca Flat/Climax Mine Corrective Action Unit in the northeastern portion of the Nevada Test Site. Well ER-2-1 was drilled as part of the Yucca Flat Corrective Action Unit Phase I drilling initiative. The well is located in north central Yucca Flat within Area 2 of the Nevada Test Site, and provided information regarding the radiological and physical environment near underground nuclear tests conducted in a saturated volcanic aquifer setting. Detailed lithologic descriptions with stratigraphic assignments are included in this report. These are based on composite drill cuttings collected every 3 meters and 83 sidewall samples taken at various depths between 113.7 and 754.4 meters, supplemented by geophysical log data. Detailed petrographic, chemical, and mineralogical studies of rock samples were conducted on 27 samples of drill cuttings. The well was collared in tuffaceous alluvium, and penetrated Tertiary-age tuffs of the Timber Mountain and Paintbrush Groups, Calico Hills and Wahmonie Formations, Crater Flat Group, Grouse Canyon Formation, before reaching total depth in the Tunnel Bed Formation.

  20. Stabilization and solidification of chromium-contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Cherne, C.A.; Thomson, B.M. [Univ. of New Mexico, Albuquerque, NM (United States). Civil Engineering Dept.; Conway, R. [Sandia National Labs., Albuquerque, NM (United States)

    1997-11-01

    Chromium-contaminated soil is a common environmental problem in the United States as a result of numerous industrial processes involving chromium. Hexavalent chromium [Cr(VI)] is the species of most concern because of its toxicity and mobility in groundwater. One method of diminishing the environmental impact of chromium is to reduce it to a trivalent oxidation state [Cr(III)], in which it is relatively insoluble and nontoxic. This study investigated a stabilization and solidification process to minimize the chromium concentration in the Toxicity Characteristic Leaching Procedure (TCLP) extract and to produce a solidified waste form with a compressive strength in the range of 150 to 300 pounds per square inch (psi). To minimize the chromium in the TCLP extract, the chromium had to be reduced to the trivalent oxidation state. The average used in this study was an alluvium contaminated with chromic and sulfuric acid solutions. The chromium concentration in the in the in situ soil was 1212 milligrams per kilogram (mg/kg) total chromium and 275 mg/kg Cr(VI). The effectiveness of iron, ferrous sulfate to reduce Cr(VI) was tested in batch experiments.

  1. Anthropogenic-Induced Changes in the Mechanism of Drylands Ephemeral Stream Recharge, Western Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Khan Z. Jadoon

    2016-04-01

    Full Text Available Wadi aquifers in Saudi Arabia historically have been recharged primarily by channel loss (infiltration during floods. Historically, seasonal groundwater levels fluctuated from land surface to about 3 m below the surface. Agricultural irrigation pumping has lowered the water table up to 35 m below the surface. The geology surrounding the fluvial system at Wadi Qidayd consists of pelitic Precambrian rocks that contribute sediments ranging in size from mud to boulders to the alluvium. Sediments within the wadi channel consist of fining upward, downstream-dipping beds, causing channel floodwaters to pass through several sediment sequences, including several mud layers, before it can reach the water table. Investigation of the wadi aquifer using field observation, geological characterization, water-level monitoring, geophysical profiles, and a hypothetical model suggests a critical water level has been reached that affects the recharge of the aquifer. The wetted front can no longer reach the water table due to the water uptake in the wetting process, downstream deflection by the clay layers, and re-emergence of water at the surface with subsequent direct and diffusive evaporative loss, and likely uptake by deep-rooted acacia trees. In many areas of the wadi system, recharge can now occur only along the channel perimeter via fractured rocks that are in direct horizontal hydraulic connection to the permeable beds above and below the water table.

  2. Hydrogeology and ground-water flow in the Edwards-Trinity aquifer-system, west-central, Texas

    Science.gov (United States)

    Kuniansky, E.L.; Ardis, A.F.

    1997-01-01

    Two finite-element ground-water flow models were developed for the Edwards–Trinity aquifer system, west-central Texas, to gain a better understanding of the flow system; one ground-water flow model was developed at a large scale to simulate the regional system and contiguous, hydraulically connected units, and one model was constructed at a smaller more detailed scale to simulate the most active areas of the system. The study area is divided into four geographic subareas: the Trans-Pecos (9,750 square miles), the Edwards Plateau (23,750 square miles), the Hill Country (5,500 square miles), and the Balcones fault zone (3,000 square miles). The major aquifers within the study area are the Edwards–Trinity aquifer underlying the Trans-Pecos and Edwards Plateau, the Trinity aquifer underlying the Hill Country, and the Edwards aquifer in the Balcones fault zone. Hydraulically connected aquifers include the High Plains aquifer north of the Edwards Plateau, and the Cenozoic Pecos alluvium aquifer adjacent to both the Trans-Pecos and the Edwards Plateau along the Pecos River. Minor contiguous aquifers include the Dockum, Ellenburger– San Saba, Marble Falls, Hickory, and Lipan, which is adjacent to the Colorado River in Tom Green and Concho Counties, Texas.

  3. A preliminary assessment of land-surface subsidence in the El Paso area, Texas

    Science.gov (United States)

    Land, L.F.; Armstrong, C.A.

    1985-01-01

    The Hueco bolson deposits in the El Paso area consist mostly of lenses of gravel, sand, silt, and clay. In the Rio Grande Valley , about 400 to 450 feet of these deposits have been eroded and replaced with as much as 200 feet of alluvium. Groundwater in the shallow alluvial aquifer in the Rio Grande Valley in the Hueco bolson aquifer outside the valley is under water table conditions, whereas groundwater in the bolson aquifer in the valley is under leaky artesian conditions. In the downtown area of El Paso, water level declines of 125 and 150 feet have occurred in the shallow and Hueco bolson aquifers, respectively. Surveys that releveled bench marks along lines to the northeast, the southeast, and along the Rio Grande commonly show subsidence of 0.2 foot and a maximum of 0.41 foot near the river. A comparison of subsidence, water level declines, and clay thickness along the three survey lines shows the expected correlation of greater subsidence for thicker accumulated clay material for a given decline in water levels. Data are not sufficient to determine if the preconsolidation stress has been exceeded. (USGS)

  4. Late Pleistocene to Holocene alluvial tableland formation in an intra-mountainous basin in a tectonically active mountain belt ― A case study in the Puli Basin, central Taiwan

    Science.gov (United States)

    Tseng, Chia-Han; Lüthgens, Christopher; Tsukamoto, Sumiko; Reimann, Tony; Frechen, Manfred; Böse, Margot

    2016-01-01

    The morphology in Taiwan is a product of high tectonic activity at the convergent margin and East Asian monsoon climate. Tablelands are prominent geomorphic features in the Puli Basin in central Taiwan. These tablelands provide an archive to understand links between past climatic evolution and tectonic events resulting in the formation of the present-day landforms. To establish a geochronological framework for the alluvium underlying the tablelands in the Puli Basin, optically stimulated luminescence dating was applied to obtain burial ages. The numerical data indicate an accumulation phase of alluvial fans in the Late Pleistocene to Early Holocene transition. The study area in the Taomi River catchment, an obvious longer precursor of the Taomi River, originating from west of the Yuchih Basin, transported the sediments forming the present-day southern tablelands. During the Pleistocene-Holocene transition, the climate changed to wetter and warmer conditions, so that slope processes might have changed and an increasing transport in the fluvial system was stimulated. Fluvial and fan terraces in other river catchments in Taiwan also indicate a period of increased fluvial transport and deposition. A geomorphic evolution model in the Puli Basin is reconstructed on the basis of the chronological framework and of sedimentological features. Fluvial processes controlled by climatic change and accompanied by tectonic activities have created the diverse topography in the Puli Basin.

  5. Nivní malakofauna Ploučnice (Severní Čechy The floodplain mollusc fauna of the Ploučnice River (North Bohemia

    Directory of Open Access Journals (Sweden)

    Lucie Juřičková

    2013-04-01

    Full Text Available This paper presents a research of the floodplain mollusc communities of the Ploučnice River (Elbe tributary, North Bohemia, Czech Republic. Altogether, 66 mollusc species (65 species of gastropods, one species of bivalve were recorded in the 35 floodplain forest sites during the research between 2007 and 2011, representing 27% of the total Czech malacofauna. More than a half of all species represents the common forest species (52% of all recorded species with some rare woodland species as Aegopinella nitidula, Daudebardia rufa, Macrogastra ventricosa, Oxychilus depressus, O. glaber and two endangered species Clausilia bidentata and Daudebardia brevipes. Rare wetland species protected by the NATURA system Vertigo angustior and vulnerable V. antivertigo were also found. The occurrence of these rare species (two of them endangered, three vulnerable, and 11 near threatened makes the Ploučnice river alluvium as an important mollusc refugium of prime conservation importance in this fragmented Czech landscape of long-term agricultural land use.

  6. LLNL Input to SNL L2 MS: Report on the Basis for Selection of Disposal Options

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, M; Blink, J A; Halsey, W G

    2011-03-02

    This mid-year deliverable has two parts. The first part is a synopsis of J. Blink's interview of the former Nevada Attorney General, Frankie Sue Del Papa, which was done in preparation for the May 18-19, 2010 Legal and Regulatory Framework Workshop held in Albuquerque. The second part is a series of sections written as input for the SNL L2 Milestone M21UF033701, due March 31, 2011. Disposal of high-level radioactive waste is categorized in this review into several categories. Section II discusses alternatives to geologic disposal: space, ice-sheets, and an engineered mountain or mausoleum. Section III discusses alternative locations for mined geologic disposal: islands, coastlines, mid-continent, and saturated versus unsaturated zone. Section IV discusses geologic disposal alternatives other than emplacement in a mine: well injection, rock melt, sub-seabed, and deep boreholes in igneous or metamorphic basement rock. Finally, Secton V discusses alternative media for mined geologic disposal: basalt, tuff, granite and other igneous/metamorphic rock, alluvium, sandstone, carbonates and chalk, shale and clay, and salt.

  7. Functioning of South Moravian Floodplain Forests (Czech Republic in Forest Environment Subject to Natural and Anthropogenic Change

    Directory of Open Access Journals (Sweden)

    Emil Klimo

    2013-01-01

    Full Text Available South Moravian floodplain forests at the confluence of the Morava and Dyje Rivers, which are related to the floodplain forests of Austria and Slovakia to a considerable degree, have been strongly affected by changes in forest environment caused by natural and anthropogenic impacts. The dominant change factors encompassed changes in the 12–14th centuries resulting in the formation of a flooded alluvium and a significant transition of hardwood floodplain to softwood floodplain. Their further development was affected particularly by forestry activities, and they saw a gradual transformation into hardwood floodplain forests with dominant species of oak, ash, hornbeam, and others. The primary impact in the 20th century was stream regulation and the construction of three water reservoirs, which resulted predominantly in changes in the groundwater table. Response to these changes was registered particularly in the herb layer. The contemporary forest management adjusts to environmental changes and makes efforts to alleviate the negative impacts of previously implemented changes through restoration projects.

  8. Water quality in the vicinity of Fenton Hill. Progress report 1981 and 1982

    Energy Technology Data Exchange (ETDEWEB)

    Purtymun, W.D.; Ferenbaugh, R.W.; Becker, N.M.; Adams, W.H.; Maes, M.N.

    1983-09-01

    As part of a continuing program of environmental studies, water quality data have been collected from established surface and ground water stations and from ponds and pond discharges at Fenton Hill Site located in the Jemez Mountains. Most of these stations were established in 1973, and water quality data have been collected since that time. There have been slight variations in the chemical quality of water from the surface and ground water locations; however, these variations are within normal seasonal fluctuations. The discharge from ponds at Fenton Hill infiltrates into canyon alluvium within 400 m of the site. Monitoring surface and spring discharge downgradient from the ponds failed to detect any effects resulting from water released from the ponds. Total dissolved solids and calcium have increased in water from well FH-1, which furnishes the water supply for the site. This increase is caused by the decreasing water level in the well resulting in yield from beds with a slightly different quality than has been found in previous years.

  9. Fluid mechanical scaling of impact craters in unconsolidated granular materials

    Science.gov (United States)

    Miranda, Colin S.; Dowling, David R.

    2015-11-01

    A single scaling law is proposed for the diameter of simple low- and high-speed impact craters in unconsolidated granular materials where spall is not apparent. The scaling law is based on the assumption that gravity- and shock-wave effects set crater size, and is formulated in terms of a dimensionless crater diameter, and an empirical combination of Froude and Mach numbers. The scaling law involves the kinetic energy and speed of the impactor, the acceleration of gravity, and the density and speed of sound in the target material. The size of the impactor enters the formulation but divides out of the final empirical result. The scaling law achieves a 98% correlation with available measurements from drop tests, ballistic tests, missile impacts, and centrifugally-enhanced gravity impacts for a variety of target materials (sand, alluvium, granulated sugar, and expanded perlite). The available measurements cover more than 10 orders of magnitude in impact energy. For subsonic and supersonic impacts, the crater diameter is found to scale with the 1/4- and 1/6-power, respectively, of the impactor kinetic energy with the exponent crossover occurring near a Mach number of unity. The final empirical formula provides insight into how impact energy partitioning depends on Mach number.

  10. Continued studies of long-term ecological effects of exposure to uranium

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, W.C.; Miera, F.R. Jr.

    1977-06-01

    Studies of the long-term consequences of exposing terrestrial ecosystems to natural and depleted uranium dispersed during explosives tests at Los Alamos Scientific Laboratory (LASL) and test firing at Eglin Air Force Base (EAFB), Florida, were continued. Soils from EAFB, sampled before and after firing of depleted uranium penetrators against armor plate targets, indicated that the upper (0- to 5-cm-deep) soil usually contained more uranium than lower (5- to 10-cm-deep) soil. However, no significant changes were apparent in samples taken before and after the test firing. E-F explosive testing site at LASL was selected for intensive study of uranium redistribution during its 33-yr use. Highest surface soil (0- to 2.5-cm-deep) uranium concentrations occurred 0 and 10 m from the detonation point and averaged 4500 ppM. Concentrations in surface soil 50 and 200 m from the firing point were usually < 15% of that value. The uranium distribution to 30-cm depths showed significant penetration into the soil. Alluvium collected 250 m from the E-F detonation area in Potrillo Canyon indicated that surface (0- to 2.5-cm-deep) uranium concentrations were about 10% of those at the detonation point, and at 2.8 km they were twice background levels.

  11. Rooting Characteristics of Vegetation Near Areas 3 and 5 Radioactive Waste Management Sites at the Nevada Test Site--Part 1

    Energy Technology Data Exchange (ETDEWEB)

    D. J. Hansen

    2003-09-30

    The U.S. Department of Energy emplaced high-specific-activity low-level radioactive wastes and limited quantities of classified transuranic wastes in Greater Confinement Disposal (GCD) boreholes from 1984 to 1989. The boreholes are located at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada Test Site (NTS) in southern Nevada. The boreholes were backfilled with native alluvium soil. The surface of these boreholes and trenches is expected to be colonized by native vegetation in the future. Considering the long-term performance of the disposal facilities, bioturbation (the disruption of buried wastes by biota) is considered a primary release mechanism for radionuclides disposed in GCD boreholes as well as trenches at both Areas 3 and 5 RWMSs. This report provides information about rooting characteristics of vegetation near Areas 3 and 5 RWMSs. Data from this report are being used to resolve uncertainties involving parameterization of performance assessment models used to characterize the biotic mixing of soils and radionuclide transport processes by biota. The objectives of this study were to: (1) survey the prior ecological literature on the NTS and identify pertinent information about the vegetation, (2) conduct limited field studies to describe the current vegetation in the vicinity of Areas 3 and 5 RWMSs so as to correlate findings with more extensive vegetation data collected at Yucca Mountain and the NTS, ( 3 ) review prior performance assessment documents and evaluate model assumptions based on current ecological information, and (4) identify data deficiencies and make recommendations for correcting such deficiencies.

  12. A hydrogeologic map of the Death Valley region, Nevada, and California, developed using GIS techniques

    Energy Technology Data Exchange (ETDEWEB)

    Faunt, C.C.; D`Agnese, F.A.; Turner, A.K.

    1997-12-31

    In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km{sup 2} along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing.

  13. Terrane Boundary Geophysical Signatures in Northwest Panay, Philippines: Results from Gravity, Seismic Refraction and Electrical Resistivity Investigations

    Directory of Open Access Journals (Sweden)

    Jillian Aira S. Gabo

    2015-01-01

    Full Text Available Northwest Panay consists of two terranes that form part of the Central Philippine collision zone: Buruanga Peninsula and Antique Range. The Buruanga Peninsula consists of a Jurassic chert-clastic-limestone sequence, typical of oceanic plate stratigraphy of the Palawan Micro-continental Block. The Antique Range is characterized by Antique Ophiolite Complex peridotites and Miocene volcanic and clastic rocks, representing obducted oceanic crust that serves as the oceanic leading edge of the collision with the Philippine Mobile Belt. The Nabas Fault is identified as the boundary between the two terranes. This study employed the gravity method to characterize the Northwest Panay subsurface structure. Results indicate higher Bouguer anomaly values for Buruanga Peninsula than those for Antique Range, separated by a sudden decrease in gravity values toward the east-southeast (ESE direction. Forward gravity data modeling indicates the presence of an underlying basaltic subducted slab in the Buruanga Peninsula. Furthermore, the Nabas Fault is characterized as an east-dipping thrust structure formed by Buruanga Peninsula basement leading edge subduction beneath Antique Range. Additional geophysical constraints were provided by shallow seismic refraction and electrical resistivity surveys. Results from both methods delineated the shallow subsurface signature of the Nabas Fault buried beneath alluvium deposits. The gravity, seismic refraction and electrical resistivity methods were consistent in identifying the Nabas Fault as the terrane boundary between the Buruanga Peninsula and the Antique Range. The three geophysical methods helped constrain the subsurface configuration in Northwest Panay.

  14. Uranium isotopes (U-234/U-238) in rivers of the Yukon Basin (Alaska and Canada) as an aid in identifying water sources, with implications for monitoring hydrologic change in arctic regions

    Science.gov (United States)

    Kraemer, Thomas F.; Brabets, Timothy P.

    2012-01-01

    The ability to detect hydrologic variation in large arctic river systems is of major importance in understanding and predicting effects of climate change in high-latitude environments. Monitoring uranium isotopes (234U and 238U) in river water of the Yukon River Basin of Alaska and northwestern Canada (2001–2005) has enhanced the ability to identify water sources to rivers, as well as detect flow changes that have occurred over the 5-year study. Uranium isotopic data for the Yukon River and major tributaries (the Porcupine and Tanana rivers) identify several sources that contribute to river flow, including: deep groundwater, seasonally frozen river-valley alluvium groundwater, and high-elevation glacial melt water. The main-stem Yukon River exhibits patterns of uranium isotopic variation at several locations that reflect input from ice melt and shallow groundwater in the spring, as well as a multi-year pattern of increased variability in timing and relative amount of water supplied from higher elevations within the basin. Results of this study demonstrate both the utility of uranium isotopes in revealing sources of water in large river systems and of incorporating uranium isotope analysis in long-term monitoring of arctic river systems that attempt to assess the effects of climate change.

  15. Groundwater arsenic contamination affecting different geologic domains in India - a review: influence of geological setting, fluvial geomorphology and Quaternary stratigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Acharyya, S.K.; Shah, B.A. [Jadavpur University, Calcutta (India). Dept. of Geological Science

    2007-10-15

    Arsenic contamination in groundwater is pervasive within lowland organic-rich Bengal Delta and narrow entrenched channels in the Middle Ganga floodplains. Local areas of Damodar fan-delta and isolated areas within the Dongargarh Proterozoic rift-zone in central India are also contaminated. In this rift-zone, arsenic is enriched in felsic magmatic rocks and weathered rocks and soils from local areas are enriched further in arsenic and iron. Late Quaternary stratigraphy, geomorphology and sedimentation have influenced groundwater arsenic contamination in alluvium that aggraded during the Holocene sea-level rise. No specific source of arsenic could be identified, although Himalaya is the main provenance for the Ganga floodplain and the Bengal Delta. Gondwana coal seams and other Peninsular Indian rocks might be sources for arsenic in the Damodar fan-delta. As-bearing pyrite or any As-mineral is nearly absent in the aquifer sediments. Arsenic mainly occurs adsorbed on hydrated-iron-oxide (HFO), which coat sediment grains and minerals. Arsenic and iron are released to groundwater by bio-mediated reductive dissolution of HFO with corresponding oxidation of organic matter.

  16. Ambient noise H/V spectral ratio in site effects estimation in Fateh jang area, Pakistan

    Institute of Scientific and Technical Information of China (English)

    S.M.Talha Qadri; Bushra Nawaz; S.H.Sajjad; Riaz Ahmad Sheikh

    2015-01-01

    Local geology or local site effect is a crucial component while conducting seismic risk assessment studies.Investigations made by utilization of ambient noise are an effective tool for local site estimation.The present study is conducted to perform site response analysis at 13 different sites within urban settlements of Fateh jang area (Pakistan).The aim of this study was achieved by utilizing Nakamura method or H/V spectral ratio method.Some important local site parameters,e.g.,the fundamental frequencies f0 of soft sediments,amplitudes A0 of corresponding H/V spectral ratios,and alluvium thicknesses over 13 sites within the study area,were measured and analyzed.The results show that the study area reflects low fundamental frequency f0.The fundamental frequencies of the sediments are highly variable and lie in a range of 0.6-13.0 Hz.Similarly,amplification factors at these sites are in the range of 2.0-4.0.

  17. Exploration of an alluvial aquifer in Oman by time-domain electromagnetic sounding

    Science.gov (United States)

    Young, M. E.; de Bruijn, R. G. M.; Al-Ismaily, A. Salim

    One-third of the population of Oman depends upon groundwater extracted from the alluvium of the Batinah Plain, on the coast of the Gulf of Oman. Deep geophysical exploration techniques were used to determine the depth and nature of the alluvium and the boundaries of the aquifer. The base and structural controls of the alluvial basin at its contact with Tertiary marine sediments and Cretaceous ophiolite were mapped with seismic reflection data, recorded originally for oil exploration. The base of the alluvium dips northward from the foothills of the Northern Oman Mountains, reaching a maximum depth of 2000m at the coast. The varying facies of the alluvium are grossly characterised by different, overlapping ranges of electrical resistivity, depending largely on the clay content and degree of cementation. Resistivities near the coast are reduced by saline intrusion. These variations of resistivity were mapped with time-domain electromagnetic sounding along 400km of profile, to distinguish among the three zones of the alluvial aquifer. The wedge of saline intrusion was also delineated, up to 10km from the coast. The thickness of the saturated gravel aquifer ranges from 20-160m in an area greater than 600km2. Résumé Un tiers de la population d'Oman est alimenté par de l'eau souterraine pompée dans les alluvions de la plaine de Batinah, sur la côte du golfe d'Oman. Des techniques d'exploration géophysique profonde ont été mises en oeuvre pour déterminer la profondeur et la nature des alluvions et les limites de l'aquifère. La base et les contrôles structuraux du bassin alluvial au contact des sédiments marins tertiaires et des ophiolites crétacées ont été cartographiés à partir des données de sismique réflexion obtenues à l'origine pour la recherche pétrolière. La base des alluvions plonge vers le nord à partir du piémont du massif septentrional d'Oman, pour atteindre une profondeur maximale de 2000m sur la côte. Les divers faciès alluviaux

  18. Investigation of the bioremediation potential of aerobic zymogenous microorganisms in soil for crude oil biodegradation

    Directory of Open Access Journals (Sweden)

    TATJANA ŠOLEVIĆ

    2011-03-01

    Full Text Available The bioremediation potential of the aerobic zymogenous microorganisms in soil (Danube alluvium, Pančevo, Serbia for crude oil biodegradation was investigated. A mixture of paraffinic types of oils was used as the substrate. The laboratory experiment of the simulated oil biodegradation lasted 15, 30, 45, 60 and 75 days. In parallel, an experiment with a control sample was conducted. Extracts were isolated from the samples with chloroform in a separation funnel. From these extracts, the hydrocarbons were isolated by column chromatography and analyzed by gas chromatography–mass spectrometry (GC–MS. n-Alkanes, isoprenoids, phenanthrene and its derivatives with one and two methyl groups were quantitatively analyzed. The ability and efficiency of zymogenous microorganisms in soil for crude oil bioremediation was assessed by comparison between the composition of samples which were exposed to the microorganisms and the control sample. The investigated microorganisms showed the highest bioremediation potential in the biodegradation of n-alkanes and isoprenoids. A considerably high bioremediation potential was confirmed in the biodegradation of phenanthrene and methyl phenanthrenes. Low bioremediation potential of these microorganisms was proven in the case of polycyclic alkanes of the sterane and triterpane types and dimethyl phenanthrenes.

  19. Analyzing the subsurface structure using seismic refraction method: Case study STMKG campus

    International Nuclear Information System (INIS)

    A geophysic survey is performed to detect subsurface structure under STMKG Campus in Pondok Betung, South Tangerang, Indonesia, using seismic refraction method. The survey used PASI 16S24-U24. The waveform data is acquired from 3 different tracks on the research location with a close range from each track. On each track we expanded 24 geofons with spacing between receiver 2 meters and the total length of each track about 48 meters. The waveform data analysed using 2 different ways. First, used a seismic refractionapplication WINSISIM 12 and second, used a Hagiwara Method. From both analysis, we known the velocity of P-wave in the first and second layer and the thickness of the first layer. From the velocity and the thickness informations we made 2-D vertical subsurface profiles. In this research, we only detect 2 layers in each tracks. The P-wave velocity of first layer is about 200-500 m/s with the thickness of this layer about 3-6 m/s. The P-wave velocity of second layer is about 400-900 m/s. From the P-wave velocity data we interpreted that both layer consisted by similar materials such as top soil, soil, sand, unsaturated gravel, alluvium and clay. But, the P-wave velocity difference between those 2 layers assumed happening because the first layer is soil embankment layer, having younger age than the layer below

  20. Potential Liquefaction of Loose Sand Lenses: Case Study In Surabaya East Coastal Plain, Indonesia

    Directory of Open Access Journals (Sweden)

    Putera Agung M. Agung

    2014-12-01

    Full Text Available The zone of east coastal Surabaya becomes the object of development for the city, especially to the east coastal plain. Although in the recent years, that area does not have a structure or heavy construction and or a high rise building yet, but in the future the zone will turn into a business area with a variety of activities.. The zone of east coastal Surabaya is an alluvium deposit area. This layer is considered as clay deposited from some rivers and sea. From general information, the typical soil stratigraphy consists of soft clay and silt layers with many sand lenses with or without coarse grained soil with a depth varying from 0.00 to 10.00 meters (m. The saturated sand lenses with a water table depth varies from 0.40 to 1.20 m is susceptible earthquake and it has a relatively large seismic amplification from base-rock due to geological and soil condition nature of the site. Liquefaction hazard of the sand lenses has to be anticipated and evaluated. For development of Surabaya city area toward the east coastal plain, all developer are recommended to give some criteria of sand lenses density and some consideration for anticipating the liquefaction hazard.

  1. Geotechnical aspects of development over reclaimed former alluvial mining land and ponds in Malaysia

    Science.gov (United States)

    Yeap, E. B.; Tan, B. K.; Chow, W. S.

    Mining of tin placers in Quaternary alluvium is the main type of mining activity in Peninsular Malaysia over the past hundred years. Worked out mines have left behind a landscape consisting of highly inhomogeneous tailing fill and numerous large and medium size ponds often underlain by thick slurries of fine clay and silt on limestone bedrock. Rapid urbanization around the two main tin mining areas in Malaysia, Kuala Lumpur and Ipoh, has led to the use of this previously mined land for residential, commercial and industrial purposes. Highly irregular karstic limestone bedrock poses major problems for the construction of high-rise buildings requiring piling to bedrock. Soft slime trapped during tailing deposition or during reclamation has caused numerous and often irreparable damage to houses built on former mining land. Characterization studies were undertaken on two ponds for their chemical, physical, mineralogical and engineering properties with the aim of finding a solution to the reclamation of slime filled mine ponds. Environmental considerations favour the slime material to be used as foundation material or as raw material for ceramic or bricks. Increase of the solid content by dewatering constitutes the best option to increase the strength of the slime material so as to make it acceptable as foundation material after further treatment. Studies indicate that a few reagents can be used to successfully dewater the slime. Development of a reclamation technique along this line is being carried out.

  2. Magnetic and gravity studies of Mono Lake, east-central, California

    Science.gov (United States)

    Athens, Noah D.; Ponce, David A.; Jayko, Angela S.; Miller, Matt; McEvoy, Bobby; Marcaida, Mae; Mangan, Margaret T.; Wilkinson, Stuart K.; McClain, James S.; Chuchel, Bruce A.; Denton, Kevin M.

    2014-01-01

    From August 26 to September 5, 2011, the U.S. Geological Survey (USGS) collected more than 600 line-kilometers of shipborne magnetic data on Mono Lake, 20 line-kilometers of ground magnetic data on Paoha Island, 50 gravity stations on Paoha and Negit Islands, and 28 rock samples on Paoha and Negit Islands, in east-central California. Magnetic and gravity investigations were undertaken in Mono Lake to study regional crustal structures and to aid in understanding the geologic framework, in particular regarding potential geothermal resources and volcanic hazards throughout Mono Basin. Furthermore, shipborne magnetic data illuminate local structures in the upper crust beneath Mono Lake where geologic exposure is absent. Magnetic and gravity methods, which sense contrasting physical properties of the subsurface, are ideal for studying Mono Lake. Exposed rock units surrounding Mono Lake consist mainly of Quaternary alluvium, lacustrine sediment, aeolian deposits, basalt, and Paleozoic granitic and metasedimentary rocks (Bailey, 1989). At Black Point, on the northwest shore of Mono Lake, there is a mafic cinder cone that was produced by a subaqueous eruption around 13.3 ka. Within Mono Lake there are several small dacite cinder cones and flows, forming Negit Island and part of Paoha Island, which also host deposits of Quaternary lacustrine sediments. The typical density and magnetic properties of young volcanic rocks contrast with those of the lacustrine sediment, enabling us to map their subsurface extent.

  3. Marine magnetic survey and onshore gravity and magnetic survey, San Pablo Bay, northern California

    Science.gov (United States)

    Ponce, David A.; Denton, Kevin M.; Watt, Janet T.

    2016-09-12

    IntroductionFrom November 2011 to August 2015, the U.S. Geological Survey (USGS) collected more than 1,000 line-kilometers (length of lines surveyed in kilometers) of marine magnetic data on San Pablo Bay, 98 onshore gravity stations, and over 27 line-kilometers of ground magnetic data in northern California. Combined magnetic and gravity investigations were undertaken to study subsurface geologic structures as an aid in understanding the geologic framework and earthquake hazard potential in the San Francisco Bay Area. Furthermore, marine magnetic data illuminate local subsurface geologic features in the shallow crust beneath San Pablo Bay where geologic exposure is absent.Magnetic and gravity methods, which reflect contrasting physical properties of the subsurface, are ideal for studying San Pablo Bay. Exposed rock units surrounding San Pablo Bay consist mainly of Jurassic Coast Range ophiolite, Great Valley sequence, Franciscan Complex rocks, Miocene sedimentary rocks, and unconsolidated alluvium (Graymer and others, 2006). The contrasting magnetic and density properties of these rocks enable us to map their subsurface extent.

  4. Analyzing the subsurface structure using seismic refraction method: Case study STMKG campus

    Energy Technology Data Exchange (ETDEWEB)

    Wibowo, Bagus Adi, E-mail: bagusadiwibowo1993@gmail.com [The State College of Meteorology, Climatology and Geophysics (STMKG), The Indonesian Meteorology, Climatology, and Geophysics Agency (BMKG), Perhubungan 1 Street, South Tangerang, 15221 (Indonesia); Ngadmanto, Drajat [The Center of Research and Development (PUSLITBANG), The Indonesian Meteorology, Climatology, and Geophysics Agency (BMKG), Angkasa I, Jakarta, 10620 (Indonesia); Daryono [The Mitigation of Earthquake and Tsunami, The Indonesian Meteorology, Climatology, and Geophysics Agency (BMKG), Angkasa I, Jakarta, 10620 (Indonesia)

    2015-04-24

    A geophysic survey is performed to detect subsurface structure under STMKG Campus in Pondok Betung, South Tangerang, Indonesia, using seismic refraction method. The survey used PASI 16S24-U24. The waveform data is acquired from 3 different tracks on the research location with a close range from each track. On each track we expanded 24 geofons with spacing between receiver 2 meters and the total length of each track about 48 meters. The waveform data analysed using 2 different ways. First, used a seismic refractionapplication WINSISIM 12 and second, used a Hagiwara Method. From both analysis, we known the velocity of P-wave in the first and second layer and the thickness of the first layer. From the velocity and the thickness informations we made 2-D vertical subsurface profiles. In this research, we only detect 2 layers in each tracks. The P-wave velocity of first layer is about 200-500 m/s with the thickness of this layer about 3-6 m/s. The P-wave velocity of second layer is about 400-900 m/s. From the P-wave velocity data we interpreted that both layer consisted by similar materials such as top soil, soil, sand, unsaturated gravel, alluvium and clay. But, the P-wave velocity difference between those 2 layers assumed happening because the first layer is soil embankment layer, having younger age than the layer below.

  5. Distribution of groundwater nitrate contamination in GIS environment: A case study, Sonqor plain

    Directory of Open Access Journals (Sweden)

    Parasto Setareh

    2014-06-01

    Full Text Available Background: Nitrate is a pollutant of groundwater resources which can results health risks such as methemoglobinemia and formation of nitrosamine compounds in higher concentration limits. The present study was aimed to determine the nitrite level, causes of pollution and zonation of nitrite concentration in drinking water resources in the villages of Sonqor. Methods: In this descriptive-analytrical study, 73 samples of all groundwater resources of Sonqor plain were taken in ,high water (March 2010 and low water (September 2011 periods. Water nitrate levels were then determined by spectrophotometry. Results were compared by national standards and analyzed by SPSS and Arcview GIS 9.3 software. Finally, the concentration distribution mapping was carried out in GIS environment and the factors affecting nitrite changes were analyzed. Results: nitrate concentration of water resources of Sonqor plain was fluctuating at 3.09-88.5 mg per liter.In one station, nitrite concentrations in the high (88.5 mg/liter and low (71.4 mg/liter water seasons were higher than the maximum limit. Based on the maps, a relatively high concentration of nitrite was observed in the Eastern and Southeastern regions. Conclusion: The findings indicated a reverse correlation between nitrite concentration changes and changes of static surface depth. Low thickness of alluvium, location of wells in the downstream farmlands, farming condition of the region, nitrate leaching from agricultural soils and wide application of nitrogen fertilizers in agriculture were considered as the causes of the pollution in one station.

  6. Regional Tectonic Control of Tertiary Mineralization and Recent Faulting in the Southern Basin-Range Province, an Application of ERTS-1 Data

    Science.gov (United States)

    Bechtold, I. C.; Liggett, M. A.; Childs, J. F.

    1973-01-01

    Research based on ERTS-1 MSS imagery and field work in the southern Basin-Range Province of California, Nevada and Arizona has shown regional tectonic control of volcanism, plutonism, mineralization and faulting. This paper covers an area centered on the Colorado River between 34 15' N and 36 45' N. During the mid-Tertiary, the area was the site of plutonism and genetically related volcanism fed by fissure systems now exposed as dike swarms. Dikes, elongate plutons, and coeval normal faults trend generally northward and are believed to have resulted from east-west crustal extension. In the extensional province, gold silver mineralization is closely related to Tertiary igneous activity. Similarities in ore, structural setting, and rock types define a metallogenic district of high potential for exploration. The ERTS imagery also provides a basis for regional inventory of small faults which cut alluvium. This capability for efficient regional surveys of Recent faulting should be considered in land use planning, geologic hazards study, civil engineering and hydrology.

  7. Health impact of living near an abandoned mine--case study: Jales mines.

    Science.gov (United States)

    Coelho, P; Silva, S; Roma-Torres, J; Costa, C; Henriques, A; Teixeira, J; Gomes, M; Mayan, O

    2007-05-01

    The activities of mining exploitation in Campo de Jales were performed in an uncontrolled way and gave rise to serious environmental contamination: rubbish depositories have been accumulated with no treatment or maintenance. An investigation developed around Jales Mine showed the existence of some chemical impact originated from the waste produced during mining activities. Some "black spots" for a wide suite of heavy metals were determined in stream sediments and alluvium drained from Jales tailings, which could constitute hazard factors for the area and potential danger for public health. The main objective of this study is to know the effects on health caused by this environmental contamination. It is a case-control study, where two populations--from Campo de Jales and Vilar de Maçada--were compared. They both have very similar living conditions, and were inquired about health issues and screening for lead and cadmium exposure. The results point out to higher prevalence of irritating symptomatology in the mucous of the eyes and respiratory system as well as higher lead and cadmium exposure in the Campo de Jales population. PMID:17321206

  8. Evidence for crustal degassing of CF4 and SF6 in Mojave Desert groundwaters

    Science.gov (United States)

    Deeds, D.A.; Vollmer, M.K.; Kulongoski, J.T.; Miller, B.R.; Muhle, J.; Harth, C.M.; Izbicki, J.A.; Hilton, David R.; Weiss, R.F.

    2008-01-01

    Dissolved tetrafluoromethane (CF4) and sulfur hexafluoride (SF6) concentrations were measured in groundwater samples from the Eastern Morongo Basin (EMB) and Mojave River Basin (MRB) located in the southern Mojave Desert, California. Both CF4 and SF6 are supersaturated with respect to equilibrium with the preindustrial atmosphere at the recharge temperatures and elevations of the Mojave Desert. These observations provide the first in situ evidence for a flux of CF4 from the lithosphere. A gradual basin-wide enhancement in dissolved CF4 and SF6 concentrations with groundwater age is consistent with release of these gases during weathering of the surrounding granitic alluvium. Dissolved CF4 and SF6 concentrations in these groundwaters also contain a deeper crustal component associated with a lithospheric flux entering the EMB and MRB through the underlying basement. The crustal flux of CF4, but not of SF6, is enhanced in the vicinity of local active fault systems due to release of crustal fluids during episodic fracture events driven by local tectonic activity. When fluxes of CF4 and SF6 into Mojave Desert groundwaters are extrapolated to the global scale they are consistent, within large uncertainties, with the fluxes required to sustain the preindustrial atmospheric abundances of CF4 and SF6. ?? 2007 Elsevier Ltd. All rights reserved.

  9. Rooting Characteristics of Vegetation near Areas 3 and 5 Radioactive Waste Management Sites at the Nevada Test Site

    International Nuclear Information System (INIS)

    The U.S. Department of Energy emplaced high-specific-activity low-level radioactive wastes and limited quantities of classified transuranic wastes in Greater Confinement Disposal (GCD) boreholes from 1984 to 1989. The boreholes are located at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada Test Site (NTS) in southern Nevada. The boreholes were backfilled with native alluvium soil. The surface of these boreholes and trenches is expected to be colonized by native vegetation in the future. Considering the long-term performance of the disposal facilities, bioturbation (the disruption of buried wastes by biota) is considered a primary release mechanism for radionuclides disposed in GCD boreholes as well as trenches at both Areas 3 and 5 RWMSs. This report provides information about rooting characteristics of vegetation near Areas 3 and 5 RWMSs. Data from this report are being used to resolve uncertainties involving parameterization of performance assessment models used to characterize the biotic mixing of soils and radionuclide transport processes by biota. The objectives of this study were to: (1) survey the prior ecological literature on the NTS and identify pertinent information about the vegetation, (2) conduct limited field studies to describe the current vegetation in the vicinity of Areas 3 and 5 RWMSs so as to correlate findings with more extensive vegetation data collected at Yucca Mountain and the NTS, (3) review prior performance assessment documents and evaluate model assumptions based on current ecological information, and (4) identify data deficiencies and make recommendations for correcting such deficiencies

  10. Rooting Characteristics of Vegetation Near Areas 3 and 5 Radioactive Waste Management Sites at the Nevada Test Site--Part 1

    International Nuclear Information System (INIS)

    The U.S. Department of Energy emplaced high-specific-activity low-level radioactive wastes and limited quantities of classified transuranic wastes in Greater Confinement Disposal (GCD) boreholes from 1984 to 1989. The boreholes are located at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada Test Site (NTS) in southern Nevada. The boreholes were backfilled with native alluvium soil. The surface of these boreholes and trenches is expected to be colonized by native vegetation in the future. Considering the long-term performance of the disposal facilities, bioturbation (the disruption of buried wastes by biota) is considered a primary release mechanism for radionuclides disposed in GCD boreholes as well as trenches at both Areas 3 and 5 RWMSs. This report provides information about rooting characteristics of vegetation near Areas 3 and 5 RWMSs. Data from this report are being used to resolve uncertainties involving parameterization of performance assessment models used to characterize the biotic mixing of soils and radionuclide transport processes by biota. The objectives of this study were to: (1) survey the prior ecological literature on the NTS and identify pertinent information about the vegetation, (2) conduct limited field studies to describe the current vegetation in the vicinity of Areas 3 and 5 RWMSs so as to correlate findings with more extensive vegetation data collected at Yucca Mountain and the NTS, ( 3 ) review prior performance assessment documents and evaluate model assumptions based on current ecological information, and (4) identify data deficiencies and make recommendations for correcting such deficiencies

  11. Assessment of Geochemical Environment for the Proposed INL Remote-Handled Low-Level Waste Disposal Facility

    Energy Technology Data Exchange (ETDEWEB)

    D. Craig Cooper

    2011-11-01

    Conservative sorption parameters have been estimated for the proposed Idaho National Laboratory Remote-Handled Low-Level Waste Disposal Facility. This analysis considers the influence of soils, concrete, and steel components on water chemistry and the influence of water chemistry on the relative partitioning of radionuclides over the life of the facility. A set of estimated conservative distribution coefficients for the primary media encountered by transported radionuclides has been recommended. These media include the vault system, concrete-sand-gravel mix, alluvium, and sedimentary interbeds. This analysis was prepared to support the performance assessment required by U.S. Department of Energy Order 435.1, 'Radioactive Waste Management.' The estimated distribution coefficients are provided to support release and transport calculations of radionuclides from the waste form through the vadose zone. A range of sorption parameters are provided for each key transport media, with recommended values being conservative. The range of uncertainty has been bounded through an assessment of most-likely-minimum and most-likely-maximum distribution coefficient values. The range allows for adequate assessment of mean facility performance while providing the basis for uncertainty analysis.

  12. Completion Report for Well Cluster ER-5-4

    Energy Technology Data Exchange (ETDEWEB)

    U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office; Bechtel Nevada

    2005-02-01

    Well Cluster ER-5-4 was drilled for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. The cluster consists of two wells, positioned about 30 meters apart on the same drill pad, constructed as part of a hydrogeologic investigation program for Frenchman Flat at the Nevada Test Site. Detailed lithologic descriptions with preliminary stratigraphic assignments for the well cluster are included in this report. These are based on composite drill cuttings collected every 3 meters, and 156 sidewall samples taken at various depths below 192 meters in both boreholes, supplemented by geophysical log data. Detailed petrographic, chemical, and mineralogical studies of rock samples were conducted on 122 samples. Well ER-5-4 penetrated approximately 1,120 meters of Quaternary and Tertiary alluvium before reaching total depth in Tertiary volcanic rocks at 1,137.5 meters. The deeper Well ER-5-4 No.2 penetrated 1,120.4 meters of alluvial sediments, and was terminated within Tertiary volcanic rocks at a depth of 2,133.6 meters, indicating that Paleozoic rocks are deeper than expected at this site.

  13. Hydrology and subsidence potential of proposed coal-lease tracts in Delta County, Colorado

    Science.gov (United States)

    Brooks, Tom

    1983-01-01

    Potential subsidence from underground coal mining and associated hydrologic impacts were investigated at two coal-lease tracts in Delta County, Colorado. Alteration of existing flow systems could affect water users in the surrounding area. The Mesaverde Formation transmits little ground water because of the neglibile transmissivity of the 1,300 feet of fine-grained sandstone, coal , and shale comprising the formation. The transmissivities of coal beds within the lower Mesaverde Formation ranged from 1.5 to 16.7 feet squared per day, and the transmissivity of the upper Mesaverde Formation, based on a single test, was 0.33 foot squared per day. Transmissivities of the alluvium ranged from 108 to 230 feet squared per day. The transmissivity of unconsolidated Quaternary deposits, determined from an aquifer test, was about 1,900 feet squared per day. Mining beneath Stevens Gulch and East Roatcap Creek could produce surface expressions of subsidence. Subsidence fractures could partly drain alluvial valley aquifers or streamflow in these mines. (USGS)

  14. Cold-climate slope deposits and landscape modifications of the Mid-Atlantic Coastal Plain, Eastern USA

    Science.gov (United States)

    Newell, W.L.; Dejong, B.D.

    2011-01-01

    The effects of Pleistocene cold-climate geomorphology are distributed across the weathered and eroded Mid-Atlantic Coastal Plain uplands from the Wisconsinan terminal moraine south to Tidewater Virginia. Cold-climate deposits and landscape modifications are superimposed on antecedent landscapes of old, weathered Neogene upland gravels and Pleistocene marine terraces that had been built during warm periods and sea-level highstands. In New Jersey, sequences of surficial deposits define a long history of repeating climate change events. To the south across the Delmarva Peninsula and southern Maryland, most antecedent topography has been obscured by Late Pleistocene surficial deposits. These are spatially variable and are collectively described as a cold-climate alloformation. The cold-climate alloformation includes time-transgressive details of climate deterioration from at least marine isotope stage (MIS) 4 through the end of MIS 2. Some deposits and landforms within the alloformation may be as young as the Younger Dryas. Southwards along the trend of the Potomac River, these deposits and their climatic affinities become diffused. In Virginia, a continuum of erosion and surficial deposits appears to be the product of ‘normal’ temperate, climate-forced processes. The cold-climate alloformation and more temperate deposits in Virginia are being partly covered by Holocene alluvium and bay mud.

  15. Effect of heterogeneity on radionuclide retardation in the alluvial aquifer near Yucca Mountain, Nevada.

    Science.gov (United States)

    Painter, S; Cvetkovic, V; Turner, D R

    2001-01-01

    The U.S. Department of Energy is currently studying Yucca Mountain, Nevada, as a potential site for a geological high-level waste repository. In the current conceptual models of radionuclide transport at Yucca Mountain, part of the transport path to pumping locations would be through an alluvial aquifer. Interactions with minerals in the alluvium are expected to retard the downstream migration of radionuclides, thereby delaying arrival times and reducing ground water concentrations. We evaluate the effectiveness of the alluvial aquifer as a transport barrier using the stochastic Lagrangian framework. A transport model is developed to account for physical and chemical heterogeneities and rate-limited mass transfer between mobile and immobile zones. The latter process is caused by small-scale heterogeneity and is thought to control the macroscopic-scale retardation in some field experiments. A geostatistical model for the spatially varying sorption parameters is developed from a site-specific database created from hydrochemical measurements and a calibrated modeling approach (Turner and Pabalan 1999). Transport of neptunium is considered as an example. The results are sensitive to the rate of transfer between mobile and immobile zones, and to spatial variability in the hydraulic conductivity. Chemical heterogeneity has only a small effect, as does correlation between hydraulic conductivity and the neptunium distribution coefficient. These results illustrate how general sensitivities can be explored with modest effort within the Lagrangian framework. Such studies complement and guide the application of more detailed numerical simulations.

  16. The diffraction of Rayleigh waves by a fluid-saturated alluvial valley in a poroelastic half-space modeled by MFS

    Science.gov (United States)

    Liu, Zhongxian; Liang, Jianwen; Wu, Chengqing

    2016-06-01

    Two dimensional diffraction of Rayleigh waves by a fluid-saturated poroelastic alluvial valley of arbitrary shape in a poroelastic half-space is investigated using the method of fundamental solutions (MFS). To satisfy the free surface boundary conditions exactly, Green's functions of compressional (PI and PII) and shear (SV) wave sources buried in a fluid-saturated poroelastic half-space are adopted. Next, the procedure for solving the scattering wave field is presented. It is verified that the MFS is of excellent accuracy and numerical stability. Numerical results illustrate that the dynamic response strongly depends on such factors as the incident frequency, the porosity of alluvium, the boundary drainage condition, and the valley shape. There is a significant difference between the diffraction of Rayleigh waves for the saturated soil case and for the corresponding dry soil case. The wave focusing effect both on the displacement and pore pressure can be observed inside the alluvial valley and the amplification effect seems most obvious in the case of higher porosity and lower frequency. Additionally, special attention should also be paid to the concentration of pore pressure, which is closely related to the site liquefaction in earthquakes.

  17. Investigations of the Fundamental Surface Reactions Involved in the Sorption and Desorption of Radionuclides

    International Nuclear Information System (INIS)

    Models for describing solution- and surface-phase reactions have been used for 30 years, but only recently applicable to complex surfaces. Duff et al., using micro-XANES, found that Pu was concentrated on Mn-oxide and smectite phases of zeolitic tuff, providing an evaluation of contaminant speciation on surfaces for modeling. Experiments at Los Alamos demonstrated that actinides display varying surface residence time distributions, probably reflective of mineral surface heterogeneity. We propose to investigate the sorption/desorption behavior of radionuclides from mineral surfaces, as effected by microorganisms, employing isolates from Nevada Test Site deep alluvium as a model system. Characterizations will include surface area, particle size distribution, x-ray diffraction (XRD), microprobe analysis, extractions, and microbiology. Surface interactions will be assessed by electron spectroscopy (XPS), x-ray absorption fine structure spectroscopy (XAFS), X-ray emission spectroscopy, transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). Desert Research Institute (DRI), University of Nevada, Reno (UNR), and University of Nevada, Las Vegas (UNLV) researchers will collaborate to enhance scientific infrastructure and the understanding of contaminant behavior on surfaces, with broader implications for the management of DOE sites.

  18. Salinization of the Upper Colorado River - Fingerprinting Geologic Salt Sources

    Science.gov (United States)

    Tuttle, Michele L.W.; Grauch, Richard I.

    2009-01-01

    Salt in the upper Colorado River is of concern for a number of political and socioeconomic reasons. Salinity limits in the 1974 U.S. agreement with Mexico require the United States to deliver Colorado River water of a particular quality to the border. Irrigation of crops, protection of wildlife habitat, and treatment for municipal water along the course of the river also place restrictions on the river's salt content. Most of the salt in the upper Colorado River at Cisco, Utah, comes from interactions of water with rock formations, their derived soil, and alluvium. Half of the salt comes from the Mancos Shale and the Eagle Valley Evaporite. Anthropogenic activities in the river basin (for example, mining, farming, petroleum exploration, and urban development) can greatly accelerate the release of constituents from these geologic materials, thus increasing the salt load of nearby streams and rivers. Evaporative concentration further concentrates these salts in several watersheds where agricultural land is extensively irrigated. Sulfur and oxygen isotopes of sulfate show the greatest promise for fingerprinting the geologic sources of salts to the upper Colorado River and its major tributaries and estimating the relative contribution from each geologic formation. Knowing the salt source, its contribution, and whether the salt is released during natural weathering or during anthropogenic activities, such as irrigation and urban development, will facilitate efforts to lower the salt content of the upper Colorado River.

  19. A probabilistic approach for earthquake hazard assessment of the Province of Eskişehir, Turkey

    Directory of Open Access Journals (Sweden)

    A. Orhan

    2007-10-01

    Full Text Available The city of Eskişehir in inner-western Turkey has experienced a destructive earthquake with Ms=6.4 in 1956 in addition to many events with magnitudes greater than 5. It is located in a wide basin having young sedimentary units and thick alluvium soils which also include liquefiable sand materials. There is also an active fault passing beneath the city center and the groundwater level is very close to the ground surface. Approximately 600 thousand people are living in the province of Eskişehir. Therefore, the city and its vicinity have a high risk, when earthquake hazard is considered.

    This paper summarizes the probabilistic seismic hazard analysis (PSHA which was performed for the province of Eskişehir and introduces seismic hazard maps produced by considering earthquakes with magnitude Ms≥4.0 occurred during the last 100-years and a seismic model composed of four seismic sources. The results of PSHA show that the average peak ground acceleration (PGA for the city center is 0.40 g for 10 percent probability of exceedance in 50 years, for rock site. The seismic hazard maps were obtained by means of a program of Geographic Information System.

  20. National Uranium Resourve Evaluation Program. Hydrogeochemical and stream sediment reconnaissance basic data for Presidio NTMS Quadrangle, Texas

    International Nuclear Information System (INIS)

    Results of a reconnaissance geochemical survey of the Presidio Quadrangle, Texas are reported. Field and laboratory data are presented for 79 groundwater samples and 105 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are displayed. A generalized geologic map of the survey area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uanium mineralization are briefly discussed. In groundwater, uranium concentrations above the 85th percentile outline areas in the northeastern portion of the quadrangle dominated by Tertiary tuffaceous sediments which isconformably overlie Cretaceous units. Other high-uranium values are observed in areas dominated by Quaternary alluvium derived from the Tertiary volcanics in the central portions of the survey area along Alamito and Cienega Creeks. The relationship between uranium and related variables in groundwater samples indicates these areas to have the best potential for uranium mineralization. In stream sediment data, uranium results indicate that the best potential for uranium mineralization occurs in Tertiary tuffaceous sediments and igneous rocks in the northeastern portion of the quadrangle and within the vicinity of the Chinati Mountains. Soluble uranium and associated elements related to vein-type uranium mineralization are observed within the vicinity of the Chinati Mountains

  1. A hydrogeologic map of the Death Valley region, Nevada, and California, developed using GIS techniques

    International Nuclear Information System (INIS)

    In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km2 along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing

  2. Constraints on early Mars atmospheric pressure inferred from small ancient craters

    CERN Document Server

    Kite, Edwin S; Lucas, Antoine; Aharonson, Oded

    2013-01-01

    The single most important control on long-term climate change on Mars is thought to be decay of the CO2-dominated atmosphere, but direct constraints on paleoatmospheric pressure P are lacking. Of particular interest is the climate that allowed rivers to flow early in Mars history, which was affected by P via direct and indirect greenhouse effects. The size of craters embedded within ancient layered sediments is a proxy for P: the smaller the minimum-sized craters that form, the thinner the past atmosphere. Here we use high-resolution orthophotos and Digital Terrain Models (DTMs) to identify ancient craters among the river deposits of Aeolis, and compare their sizes to models of atmospheric filtering of impactors by thicker atmospheres. The best fit is P <= 760+/-70 mbar, rising to P <= 1640+/-180 mbar if rimmed circular mesas are excluded. Surveys tend to undercount smaller craters, so these fits are upper limits. Our work assumes target properties appropriate for desert alluvium: if sediment developed ...

  3. Investigation of the Transient Response of Gower Gulch to Forced Diversion, Death Valley, California

    Science.gov (United States)

    Schultz, L. L.; Snyder, N. P.

    2005-12-01

    We document sequential stages of the evolution of Gower Gulch in response to a forced diversion in 1941, using aerial photographs and field surveys. This artificial stream capture provides a rare opportunity to evaluate initial channel conditions and the ongoing response of the system. Five sets of aerial photographs (flight dates 1948, 1960, 1971, 1982, and 1995) have been orthorectified or registered for thorough geomorphic analysis. The response differs throughout the channel, depending on pre-diversion conditions and lithology. At the diversion point and the mouth, bedrock-floored knickzones have formed. Channel narrowing and incision characterize these steep reaches, with upstream knickpoint migration by pothole abrasion. In the central part of the channel, underlain by soft, fine-grained sedimentary rocks, the channel is covered in alluvium and has widened from an average of 14.8 m in 1948 to 24.6 m in 2005. Incision in this area is approximately 1-3 m, as indicated by tributary terraces. In the alluvial fan, the channel has incised up to 6.9 m, and widened from 10.9 m to 45.6 m. Above the diversion, Furnace Creek Wash has narrowed by approximately 12 meters since 1948.

  4. Episodic bedrock erosion by gully-head migration, Colorado High Plains, USA

    Science.gov (United States)

    Rengers, Francis; Tucker, G.E.; Mahan, Shannon

    2016-01-01

    This study explores the frequency of bedrock exposure in a soil-mantled low-relief (i.e. non-mountainous) landscape. In the High Plains of eastern Colorado, gully headcuts are among the few erosional features that will incise through the soil mantle to expose bedrock. We measured the last time of bedrock exposure using optically stimulated luminescence dating of alluvial sediment overlying bedrock in gully headcuts. Our dating suggests that headcuts in adjacent gullies expose bedrock asynchronously, and therefore, the headcuts are unlikely to have been triggered by a base-level drop in the trunk stream. This finding supports the hypothesis that headcuts can develop locally in gullies as a result of focused scour in locations where hydraulic stress during a flash flood is sufficiently high, and/or ground cover is sufficiently weak, to generate a scour hole that undermines vegetation. Alluvium dating also reveals that gullies have been a persistent part of this landscape since the early Holocene. 

  5. Hydrothermal alteration at Roosevelt Hot Springs KGRA: DDH 1976-1

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, N.L.; Parry, W.T.

    1977-09-01

    Hot waters of the Roosevelt Thermal Area, Utah, have altered granitic rocks and detritus of the Mineral Range pluton, Utah. Alteration and mineral deposition recognized in a 200' drill core from DDH 1-76 is most intense in the upper 100 feet which consists of altered alluvium and opal deposits; the lower 100 feet is weakly altered quartz monzonite. Petrographic, x-ray, and chemical methods were used to characterize systematic changes in chemistry and mineralogy. Comparison of the alteration mineral assemblages with known water chemistry and equilibrium activity diagrams suggests that a simple solution equilibrium model cannot account for the alteration. A model is proposed in which upward moving thermal water supersaturated with respect to quartz and a downward moving cool water undersaturated with respect to quartz produces the observed alteration. An estimate of the heat flow contributions from hydrothermal alteration was made by calculating reaction enthalpies for alteration reactions at each depth. The estimated heat flow varied from .02 HFU (for 200' depth, 400,000 yr duration, and no sulfur oxidation) to 67 HFU (for 5,000' depth, 1,000 yr duration, and all sulfur oxidized from sulfide). Heat flow contributions from hydrothermal alteration are comparable with those from a cooling granitic magma.

  6. Strontium isotope as an indicator of fluid residence from selected geothermal fields in China

    International Nuclear Information System (INIS)

    The purpose of this study is to develop a new indicator of fluid residence in complex geothermal systems. The method is based on a serious of assumptions in geothermal systems. Firstly, the Yangbajain geothermal field of Tibet is chosen to study the behaviors of strontium isotope and verify these assumptions when a deeper thermal fluid ascends. In the past years, two reservoirs have been identified at different depths in the Yangbajain field. A shallow reservoir is found at depths less than 450m, with temperature varying from 150 deg. C to 170 deg. C and decreasing toward the southeast. Parent rock in the shallow reservoir is altered Himalayan granite in the northwest part of the field and Quaternary alluvium in the southeast part. A deep reservoir is found at depths in the range from 750m to 1400m, with temperature higher than 250 deg. C. Parent rock in the deep reservoir is fractured Himalayan granite. Both thermal fluids from the shallow and deep reservoir and cold groundwater are collected for the analysis of chemical compositions and strontium isotope. Rock samples are also collected at different depths in wells for strontium isotope measurement

  7. Groundwater arsenic contamination in Manipur, one of the seven North-Eastern Hill states of India: a future danger

    Science.gov (United States)

    Chakraborti, Dipankar; Singh, E. Jayantakumar; Das, Bhaskar; Shah, Babar Ali; Hossain, M. Amir; Nayak, Bishwajit; Ahamed, Sad; Singh, N. Rajmuhon

    2008-11-01

    Manipur State, with a population of 2.29 million, is one of the seven North-Eastern Hill states in India, and is severely affected by groundwater arsenic contamination. Manipur has nine districts out of which four are in Manipur Valley where 59% of the people live on 10% of the land. These four districts are all arsenic contaminated. We analysed water samples from 628 tubewells for arsenic out of an expected total 2,014 tubewells in the Manipur Valley. Analyzed samples, 63.3%, contained >10 μg/l of arsenic, 23.2% between 10 and 50 μg/l, and 40% >50 μg/l. The percentages of contaminated wells above 10 and 50 μg/l are higher than in other arsenic affected states and countries of the Ganga-Meghna-Brahmaputra (GMB) Plain. Unlike on the GMB plains, in Manipur there is no systematic relation between arsenic concentration and the depth of tubewells. The source of arsenic in GMB Plain is sediments derived from the Himalaya and surrounding mountains. North-Eastern Hill states were formed at late phase of Himalaya orogeny, and so it will be found in the future that groundwater arsenic contamination in the valleys of other North-Eastern Hill states. Arsenic contaminated aquifers in Manipur Valley are mainly located within the Newer Alluvium. In Manipur, the high rainfall and abundant surface water resources can be exploited to avoid repeating the mass arsenic poisoning that has occurred on the GMB plains.

  8. Compilation and preliminary interpretation of hydrologic data for the Weldon Spring radioactive waste-disposal sites, St. Charles County, Missouri - A progress report

    International Nuclear Information System (INIS)

    From 1957 to 1966 the plant converted uranium-ore concentrates and recycles scrap to pure uranium trioxide, uranium tetrafluoride, and uranium metal. Residues from these operations were pumped to four large pits that had been excavated near the plant. Small springs and losing streams are present in the area. Water overlying the residue in the pits has a large concentration of dissolved solids and a different chemical composition compared to the native groundwater and surface water. This difference is indicated by the concentrations of calcium, sodium, sulfate, nitrate, fluoride, uranium, radium, lithium, molybdenum, strontium, and vanadium, all of which are greater than natural or background concentrations. Water from Burgermeister Spring, located about 1.5 miles north of the chemical plant area, contains uranium and nitrate concentrations greater than background concentrations. Groundwater in the shallow bedrock aquifer moves northward from the vicinity of the chemical plant toward Dardenne Creek. An abandoned limestone quarry several miles southwest of the chemical plant also has been used for the disposal of radioactive waste and rubble. Groundwater flow from the quarry area is southward through the alluvium, away from the quarry and toward the Missouri River. Water from a well 4,000 ft southeast of the quarry was analyzed; there was no indication of contamination from the quarry. Additional water quality and water level data are needed to determine if water from the quarry moves toward the well field. 24 refs., 14 figs., 14 tabs

  9. Influence of Rhizobacterial Inoculation on Growth of the Sweetpotato Cultivar

    Directory of Open Access Journals (Sweden)

    Y. Farzana

    2005-01-01

    Full Text Available Sweetpotato (Ipomoea batatas L. is the most important of local tuber crops in Malaysia. It is usually planted on marginal soils such as peat and sandy soils. Malaysian’s are consumed a lot of sweetpotatoes and its production requires high fertilizer input, which can lead to increased production cost and environment problems. The use of biofertilizer and bioenhancer such as N2 (nitrogen fixing bacteria and beneficial microorganism can reduce chemical fertilizer applications and consequently lower production cost. The pot experiment was conducted to determine the influence of rhizobacterial isolates on the response of sweetpotato plant growth. A total of five rhizobacterial isolates capable of producing indole-3-acetic acid (IAA were used. Four of the isolates were collected from sweetpotato rhizosphere and one isolate was imported. Cuttings of sweetpotato cultivars melaka and oren were planted in plastic pots containing alluvium soil. Cultures of the rhizobacterial isolates were inoculated at planting time, two and four weeks after planting. Plants were harvested 60 days after planting. The results showed that, three of isolates significantly increased the plant growth and the N, P, K, Ca and Mg uptake of sweetpotato cultivar.

  10. Ecological characteristics of a Hungarian summer truffle (Tuber aestivum Vittad. producing area

    Directory of Open Access Journals (Sweden)

    Csorbai A. Gógán

    2013-12-01

    Full Text Available Hungary has outstanding environment for natural truffle production in some regions including plain and hilly areas. The most famous of all the natural summer truffle (Tuber aestivum Vittad. habitats is the commonly called Jászság region. This area is situated in the middle of Hungary, between river Danube and Tisza. The flatland area is basically covered by river alluviums with main soils of chernozems, fluvisols, solonchaks and arenosols. Climate of the region is typically continental: warm and dry summers and cold winters vary. The area is traditionally of agricultural use, although strong afforestation was made in the late 1950’s. The English oak (Quercus robur L. populations planted at that time gave a basis for current excellent truffle production. Nowadays the region has proved to be the best natural summer truffle (T. aestivum producing area of Hungary with early season opening (June and high quality truffles as early as August. In the research the best truffle producing forest blocks were selected for ecological investigation. Results of the detailed site description showed uniform climate characteristics and dominance of English oak (Q. robur or mixed English oak-Turkey oak (Quercus cerris L. forests. Soil types revealed differences from earlier findings: dominance of gleysols and water affected chernozems was declared. Soil chemical parameters are in accordance with literature data: pH, organic matter and active carbonate content of the examined soils fall within the range indicated as the requirement of T. aestivum.

  11. Chemical pools of Cd in sludge-treated soils and their contribution of Rajmash (Phaseolus vulgaris L)

    International Nuclear Information System (INIS)

    To study the influence of application of organically complexed Cd on Rajmash (Phaseo/us vu/garis L,), a pot experiment was conducted on ten sewage sludge-treated old), alluvium, non-calcareoUS, and non-saline soils of Patna wherein a rajmash crop was grown after treatment with O and 5 mg kg-l isotopicaIly tagged and organically-complexed Cd. The results indicated that the application of Cd through cadmium-fulvic acid complex in soils did not influence the dry matter yield of the crop, though it significantly increased the concentration of Cd in the plants and its uptake by the crop, The soil organic carbon content, cation exchange, capacity, clay content and pH of the soils were found to be the dominant determinants of Cd in plants and its uptake by the crop. The path analysis and stepwise regression analysis indicated that the water soluble + exchangeable Cd and organically complexed Cd were the two major chemical pools of Cd in soils responsible for supply of Cd 10 the plants

  12. Observation of time dependent dispersion in laboratory scale experiments with intact tuff

    International Nuclear Information System (INIS)

    The migration of radionuclides through intact tuff was studied using tuff from Yucca Mountain, Nevada. The tuff samples were both highly zeolitized ash-fall tuff from the Calico Hills and densely welded devitrified tuff from the Topopah Springs member of the Paintbrush tuff. Tritiated water and pertechnetate were used as conservative tracers. The sorbing tracers 85Sr, 137Cs, and 133Ba were used with the devitrified tuff only. Greater tailing in the elution curves of the densely welded tuff samples was observed that could be fit by adjusting the dispersion coefficient in the conventional Advection Dispersion Equation, ADE. The curves could be fit using time dependent dispersion as was previously observed for sediments and alluvium by Dieulin, Matheron, and de Marsily. The peak of strontium concentration was expected to arrive after 1.5 years based on the conventional ADE and assuming a linear Kd of 26 ml/g. The observed elution had significant strontium in the first sample taken at 2 weeks after injection. The peak in the strontium elution occurred at 5 weeks. The correct arrival time for the strontium peak was achieved using a one dimensional analytic solution with time dependent dispersion. The dispersion coefficient as a function of time used to fit the conservative tracers was found to predict the peak arrival of the sorbing tracers. The Kd used was the Kd determined by the batch method on crushed tuff. 23 refs., 9 figs., 2 tabs

  13. Description of the physical environment and coal-mining history of west-central Indiana, with emphasis on six small watersheds

    International Nuclear Information System (INIS)

    West-central Indiana is underlain by coal-bearing Pennsylvanian rocks. Nearly all of the area has been glaciated at least once and is characterized by wide flood plains and broad, flat uplands. The most productive aquifers are confined or unconfined outwash aquifers located along the major rivers. Bedrock aquifers are regionally insignificant but are the sole source of groundwater for areas that lack outwash, alluvium, or sand and gravel lenses in till. Indiana has > 17 billion short tons of recoverable coal reserves; about 11% can be mined by surface methods. More than 50,000 acres in west-central Indiana were disturbed by surface coal mining from 1941 through 1980. Ridges of mine spoil have been graded to a gently rolling topography. Soils are well drained and consist of 6 to 12 inches of silt-loam topsoil that was stockpiled and then replaced over shale and sandstone fragments of the graded mine spoil. Grasses and legumes form the vegetative cover in each watershed. Pond Creek and the unnamed tributary to Big Branch are streams that drain mined and unreclaimed watersheds. Approximately one-half of the Pond Creek watershed is unmined,agricultural land. Soils are very well drained shaly silty loams that have formed on steeply sloping spoil banks. Both watersheds contain numerous impoundments of water and have enclosed areas that do not contribute surface runoff to streamflow. The ridges of mine spoil are covered with pine trees, but much of the soil surface is devoid of vegetation

  14. Hydrophytometeorological indexes of Virginia type tobacco

    Directory of Open Access Journals (Sweden)

    Aksić Miroljub

    2008-01-01

    Full Text Available The field trial of Virginia type tobacco (Hevesi-9 was set in irrigation conditions, in the vicinity of Brzi Brod village, Nišava River's valley, on the alluvium soil type. Water consumption for evapotranspiration, at the irrigated variant and the control one, was calculated for each month and the whole vegetation period, by making the balance between water consumption from the soil layer to 2m under the ground, total precipitation amount in the vegetation and water added by irrigation. Hydro-phyto-meteorological indexes of Virginia type tobacco were calculated in regard to air temperature, relative air humidity, air humidity deficiency, sunshine duration and global radiation. Among the six meteorological elements (the above mentioned five and wind speed analyzed in the studied period, the highest level of correlation with tobacco ETP was shown by air temperature (r=0.88, so the use of hydro-phytotermic index could be recommended for calculation of potential evapotranspiration in irrigation practice.

  15. Hydrodynamic caracterisation of an heterogeneous aquifer system under semi-arid climate

    Science.gov (United States)

    Drias, T.; Toubal, A. Ch

    2009-04-01

    The studied zone is a part of the Mellegne's (North-East of Algeria) under pound, this zone is characterised by its semi-arid climate. The water bearing system is formed by the plio-quaternairy alluviums resting on a marley substratuim of age Eocene. The geostatiscitcs approach of the hydrodynamics parameters (Hydrolic load, transmisivity) allowed the study of their spatial distrubution (casting) by the method of Krigeage by blocks and the identification of zones with water-bearing potentialities. In this respect, the zone of Ain Chabro which, is situated in the South of the plain shows the best values of the transmisivity...... The use of a bidimensinnel model in the differences ended in the permanent regime allowed us to establish the global balence sheet (overall assessment) of the tablecloth and to refine the transmisivity field. These would vary more exactley between 10-4 to 10-2 m²/s. The method associating the probability appraoch of Krigeage to that determining the model has facilited the wedging of the model and clarified the inflitration value. Keys words: hydrodynamics, geostatiscitcs, Modeling, Chabro, Tébessa.

  16. Heterogeneous aquifer system modelisation under semi-arid climate

    Science.gov (United States)

    Drias, Tarek; Toubal, Ahmed Cherif

    2010-05-01

    The studied zone is a part of the Mellegne's (North-East of Algeria) under pound, this zone is characterised by its semi-arid climate. The water bearing system is formed by the plio-quaternairy alluviums resting on a marley substratuim of age Eocene. The geostatiscitcs approach of the hydrodynamics parameters (Hydrolic load, transmisivity) allowed the study of their spatial distrubution (casting) by the method of Krigeage by blocks and the identification of zones with water-bearing potentialities. In this respect, the zone of Ain Chabro which, is situated in the South of the plain shows the best values of the transmisivity...... The use of a bidimensinnel model in the differences ended in the permanent regime allowed us to establish the global balence sheet (overall assessment) of the tablecloth and to refine the transmisivity field. These would vary more exactley between 10-4 to 10-2 m²/s. The method associating the probability appraoch of Krigeage to that determining the model has facilited the wedging of the model and clarified the inflitration value. Keys words: hydrodynamics, geostatiscitcs, Modeling, Chabro, Tébessa.

  17. Mineral potential for sediment-hosted copper deposits in the Islamic Republic of Mauritania (phase V, deliverable 75): Chapter K in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

    Science.gov (United States)

    Taylor, Cliff D.; Giles, Stuart A.

    2015-01-01

    The presence of Neoproterozoic through Cambrian, continental, siliciclastic sedimentary rocks interbedded with dolomitic carbonates, shales, and glacial tillites similar to the Katanga Supergroup host rocks of the Central African Copperbelt and other sediment-hosted copper-bearing Proterozoic sequences worldwide, is first order criteria for consideration of the Neoproterozoic units of the Taoudeni Basin in Mauritania as prospective for sediment-hosted copper deposits. Review of the National Mineral Occurrences Database (Marsh and Anderson, 2015) and previous literature suggest that only a handful of small sediment-hosted copper occurrences have been found to date in Mauritania and that the resource potential for this deposit type is low. In the northern Taoudeni Basin, the most important occurrence is at Taradent. This occurrence consists of three mineralized horizons in the lower Neoproterozoic Char Group in three outcrop areas separated by alluvium over a strike length of 12 kilometers (km). The most extensively mineralized horizon consists of malachite and disseminated copper sulfides, and is concentrated at the base of a dolomitic interval, consistent with a reduced faciestype sediment-hosted copper deposit model. Additional and poorly described copper occurrences in the Taoudeni Basin margin sedimentary rocks in northeastern Mauritania, such as Chegga Guettatira and Sidi Bara, may be sediment-hosted copper occurrences and extend the potential throughout this portion of the Basin.

  18. Physical-Property Measurements on Core samples from Drill-Holes DB-1 and DB-2, Blue Mountain Geothermal Prospect, North-Central Nevada

    Science.gov (United States)

    Ponce, David A.; Watt, Janet T.; Casteel, John; Logsdon, Grant

    2009-01-01

    From May to June 2008, the U.S. Geological Survey (USGS) collected and measured physical properties on 36 core samples from drill-hole Deep Blue No. 1 (DB-1) and 46 samples from drill-hole Deep Blue No. 2 (DB-2) along the west side of Blue Mountain about 40 km west of Winnemucca, Nev. These data were collected as part of an effort to determine the geophysical setting of the Blue Mountain geothermal prospect as an aid to understanding the geologic framework of geothermal systems throughout the Great Basin. The physical properties of these rocks and other rock types in the area create a distinguishable pattern of gravity and magnetic anomalies that can be used to infer their subsurface geologic structure. Drill-holes DB-1 and DB-2 were spudded in alluvium on the western flank of Blue Mountain in 2002 and 2004, respectively, and are about 1 km apart. Drill-hole DB-1 is at a ground elevation of 1,325 m and was drilled to a depth of 672 m and drill-hole DB-2 is at a ground elevation of 1,392 m and was drilled to a depth of 1522 m. Diameter of the core samples is 6.4 cm. These drill holes penetrate Jurassic and Triassic metasedimentary rocks predominantly consisting of argillite, mudstone, and sandstone; Tertiary diorite and gabbro; and younger Tertiary felsic dikes.

  19. Delineation of uranium potential zones in Gwalior basin, India using multi-sensor data sets

    International Nuclear Information System (INIS)

    Gwalior basin forms an E-W trending elongated basin covered by Gangetic Alluvium in the north and east, by Kaimur Group sediments in the west and underlain by Bundelkhand granite in the south. IRS LISS3 and PAN Satellite images were used for the interpretation of geomorphology, geology and structure of the Basin. Airborne radiometric and magnetic survey data was processed, images generated and interpreted. The output data has been organized in to vector, raster and tabular data. The maps showing geology, structure and uranium occurrences were digitised as vector data and georeferenced. The data related to map features were tabulated and made interactive by using unique ID for each feature. Digital enhanced satellite, Airborne gamma ray spectrometric (AGRS) and magnetic images were incorporated in the form of raster data. Atomic Minerals Directorate for Exploration and Research (AMD) has intensified uranium exploration activities in Proterozoic basins of India. The Proterozoic Gwalior basin was evaluated for uranium potential by the integration of available data sets using Arc GIS. Thematic Maps on detailed scale (1:25000) were generated by integration of the geology, structure, ground uranium occurrences and AGRS uranium anomaly zones. Based on the thematic maps and uranium exploration knowledge Uranium potential zones were delineated. (author)

  20. Hydrogeochemistry and groundwater quality assessment of lower part of the Ponnaiyar River Basin, Cuddalore district, South India.

    Science.gov (United States)

    Jeevanandam, M; Kannan, R; Srinivasalu, S; Rammohan, V

    2007-09-01

    The Lower Ponnaiyar River Basin forms an important groundwater province in South India constituted by Tertiary formations dominated by sandstones and overlain by alluvium. The region enjoyed artesian conditions 50 years back but at present frequent failure of monsoon and over exploitation is threatening the aquifer. Further, extensive agricultural and industrial activities and urbanization has resulted in the increase in demand and contamination of the aquifer. To identify the sources and quality of groundwater, water samples from 47 bore wells were collected in an area of 154 km2 and were analysed for major ions and trace metals. The results reveal that the groundwater in many places is contaminated by higher concentrations of NO3, Cl, PO4 and Fe. Four major hydrochemical facies Ca-Mg-Cl, Na-Cl, Ca-HCO3 and Na-HCO3 were identified using Piper trilinear diagram. Salinity, sodium adsorption ratio, and sodium percentage indicate that most of the groundwater samples are not suitable for irrigation as well as for domestic purposes and far from drinking water standards. The most serious pollution threat to groundwater is from nitrate ions, which are associated with sewage and fertilizers application. The present state of the quality of the lower part of Ponnaiyar River Basin is of great concern and the higher concentration of toxic metals (Fe and Ni) may entail various health hazards. PMID:17180415

  1. Failure characteristics of surface vertical wells for relieved coal gas and their influencing factors in Huainan mining area

    Institute of Scientific and Technical Information of China (English)

    Xu Hongjie; Sang Shuxun; Fang Liangcai; Huang Huazhou; Ren Bo

    2011-01-01

    Based on data from through-hole and logging, we studied the failure characteristics of surface drainage wells for relieved coal gas in Huainan mining area and its influencing factors. The results show that the damaged positions of drainage wells are mainly located at the thick clay layer in the low alluvium and the lithological interface in the upper section of bedrock in west mining area. The failure depth of casing is 244-670 m and concentrates at about 270-460 m deep. These damaged positions are mainly located in the bending zone according to three zones of rock layers in the vertical section above the roof divided. Generally, the casing begins to deform or damage before the face line about 30-150 m. Special formation structure and rock mass properties are the direct causes of the casing failure, high mining height and fast advancing speed are fundamental reasons for rock mass damage. However, the borehole configuration and spacing to the casing failure are not very clear.

  2. Spatial and temporal variation in methane distribution at the ground water/surface water interface in headwater catchments

    Energy Technology Data Exchange (ETDEWEB)

    Baker, M.A.; Dahm, C.N.; Valett, H.M.; Morrice, J.A.; Henry, K.S.; Campana, M.E.; Wroblicky, G.J. [Univ. of New Mexico, Albuquerque, NM (United States)

    1994-12-31

    High concentrations of methane can be found in anoxic zones of ground water near its interface with surface water in montane streams. Lithology, sediment characteristics, flow regimes and season affect the concentration and distribution of methane. Seasonal and spatial patterns of methane distribution were studied in surface and subsurface waters from three first-order montane streams in New Mexico. Alluvium at Aspen Creek (sandstone/siltstone) has low hydraulic conductivity, Rio Calaveras has intermediate hydraulic conductivity (volcanic tuff), and Gallina creek has high hydraulic conductivity (granite/gneiss). Methane is abundant (often >100 {mu}g/L) in ground water samples from the sites with lower hydraulic conductivity, especially with base flow discharge during late summer. Concentrations of methane are lowest at Gallina Creek, the site with high hydraulic conductivity. Methane concentrations are generally lowest during the winter and following spring snow melt at all three sites. Within a site, methane concentrations are commonly high in zones of ground water discharge (upwelling) and low in zones of ground water recharge (downwelling). Surface waters in all three sites are supersaturated with methane, indicating production and/or import form adjacent ground water environments.

  3. Soil intervention as a strategy for lead exposure prevention: the New Orleans lead-safe childcare playground project.

    Science.gov (United States)

    Mielke, Howard W; Covington, Tina P; Mielke, Paul W; Wolman, Fredericka J; Powell, Eric T; Gonzales, Chris R

    2011-01-01

    The feasibility of reducing children's exposure to lead (Pb) polluted soil in New Orleans is tested. Childcare centers (median = 48 children) are often located in former residences. The extent of soil Pb was determined by selecting centers in both the core and outlying areas. The initial 558 mg/kg median soil Pb (range 14-3692 mg/kg) decreased to median 4.1 mg/kg (range 2.2-26.1 mg/kg) after intervention with geotextile covered by 15 cm of river alluvium. Pb loading decreased from a median of 4887 μg/m(2) (454 μg/ft(2)) range 603-56650 μg/m(2) (56-5263 μg/ft(2)) to a median of 398 μg/m(2) (37 μg/ft(2)) range 86-980 μg/m(2) (8-91 μg/ft(2)). Multi-Response Permutation Procedures indicate similar (P-values = 0.160-0.231) soil Pb at childcare centers compared to soil Pb of nearby residential communities. At ∼$100 per child, soil Pb and surface loading were reduced within hours, advancing an upstream intervention conceptualization about Pb exposure prevention.

  4. Conditions of Sediment Transport of Styr Basin Rivers

    Directory of Open Access Journals (Sweden)

    Kostiantyn Danko

    2016-06-01

    Full Text Available The paper presents the results of studies of the conditions of sediment transport of Styr basin rivers, tributaries of the right bank of Pripyat, which were held on 9 rivers of the basin and 2 streams of the Styr River (Stara Styr and Prostyr. According to 30 representative cross-sections of the studied rivers, the hydraulic parameters of channels are measured and channel alluvium is sampled to determine its coarseness. The average flow rates under the bankfull stage are set for the mentioned areas and non-eroding and eroding velocities of the stream flow are calculated. It is determined that the passage of bankfull stages in edges complies with the conditions of dynamic equilibrium of the erosion-accumulative processes. The ratios of average flow velocities under the bankfull stage with non-eroding and eroding velocities enable determining the orientation of channel deformations in the areas of the rivers. A new approach to the determination of non-eroding velocities for unexplored areas of the rivers is represented, which is based on the dependence of non-eroding and average flow velocities at the bankfull stage. It is shown that an increase in slopes and velocities of the stream of the Styr River cause the activation of channel processes down the river.

  5. Ground motions around a semi-circular valley partially filled with an inclined alluvial layer under SH-polarized excitation

    Science.gov (United States)

    Chang, Kao-Hao; Tsaur, Deng-How; Wang, Jeen-Hwa

    2014-12-01

    A simplified mathematical model, composed of a semi-circular valley partially filled with an inclined alluvial layer under plane SH-wave incidence, is presented. To evaluate the site response theoretically, a rigorous series solution is derived via the region-matching technique. For angular wavefunctions constrained by an inclined free surface, the original form of Graf's addition formula is recast to arbitrarily shift the local coordinate system. The valley geometry, filling material, angle of incidence, and wave frequency are taken as significant parameters in exploring the site effect on ground motions. Also included are the frequency- and time-domain computations. Two canonical cases, the semi-circular vacant canyon and the fully filled semi-circular alluvial valley, with exact analytical solutions, and the partly horizontally filled case previously studied, are taken to be particular cases of the proposed general model. Steady-state results show that the peak amplitudes of motion may increase at low frequencies when the filling layer inclines to the illuminated region. At low-grazing incidence, the phenomenon of wave focusing becomes evident on the shadow side of the filling layer. Transient-state simulations elucidate how a sequence of surface waves travel on the topmost alluvium along opposite directions and interfere with multiple reflected waves within the filling layer.

  6. Seismic Characterization of Basalt Topography at Two Candidate Sites for the INL Remote-Handled Low-Level Waste Disposal Project

    Energy Technology Data Exchange (ETDEWEB)

    Jeff Sondrup; Gail Heath; Trent Armstrong; Annette Shafer; Jesse Bennett; Clark Scott

    2011-04-01

    This report presents the seismic refraction results from the depth to bed rock surveys for two areas being considered for the Remote-Handled Low-Level Waste (RH-LLW) disposal facility at the Idaho National Laboratory. The first area (Site 5) surveyed is located southwest of the Advanced Test Reactor Complex and the second (Site 34) is located west of Lincoln Boulevard near the southwest corner of the Idaho Nuclear Technology and Engineering Center (INTEC). At Site 5, large area and smaller-scale detailed surveys were performed. At Site 34, a large area survey was performed. The purpose of the surveys was to define the topography of the interface between the surficial alluvium and underlying basalt. Seismic data were first collected and processed using seismic refraction tomographic inversion. Three-dimensional images for both sites were rendered from the data to image the depth and velocities of the subsurface layers. Based on the interpreted top of basalt data at Site 5, a more detailed survey was conducted to refine depth to basalt. This report briefly covers relevant issues in the collection, processing and inversion of the seismic refraction data and in the imaging process. Included are the parameters for inversion and result rendering and visualization such as the inclusion of physical features. Results from the processing effort presented in this report include fence diagrams of the earth model, for the large area surveys and iso-velocity surfaces and cross sections from the detailed survey.

  7. Stable-isotope studies of groundwaters in southeastern New Mexico

    International Nuclear Information System (INIS)

    Oxygen-18/16 and deuterium/hydrogen ratio measurements have been made on groundwaters sampled according to specific field criteria applied during pump tests of the Rustler Formation in Nash Draw, a solution-subsidence valley west of the WIPP site in the northern Delaware Basin of southeastern New Mexico. Comparison of these data with similar measurements on other groundwaters from the northern Delaware Basin indicates two nonoverlapping populations of meteoric groundwaters. Most of the Rustler waters in Nash Draw and at the WIPP site and older waters from the eastern two-thirds of the Capitan Limestone constitute one population, while unconfined groundwaters originating as observable modern surface recharge to alluvium, the near-surface Rustler in southwestern Nash Draw, and the Capitan in the Guadalupe Mountains (Carlsbad Caverns) constitute the other. The isotopic distinction suggests that Rustler groundwater in most of Nash Draw and at the WIPP site is not receiving significant modern meteoric recharge. A likely explanation for this distinction is that meteoric recharge to most of the Rustler and Capitan took place in the geologic past under climatic conditions significantly different from the present. 25 refs., 4 figs., 2 tabs

  8. Use of slim holes for reservoir evaluation at the Steamboat Hills Geothermal Field, Nevada, USA

    Energy Technology Data Exchange (ETDEWEB)

    Combs, Jim; Goranson, Colin

    1994-01-20

    Three slim holes were drilled at the Steamboat Hills Geothermal Field in northwestern Nevada about 15 km south of Reno. The slim holes were drilled to investigate the geologic conditions, thermal regime and productive characteristics of the geothermal system. They were completed through a geologic sequence consisting of alluvium cemented by geothermal fluids, volcaniclastic materials, and granodiorite. Numerous fractures, mostly sealed, were encountered throughout the drilled depth; however, several open fractures in the granodiorite, dipping between 65 and 90{degree}, had apertures up to 13 mm in width. The depths of the slim holes vary from 262 to 277 m with open-hole diameters of 76 mm. Pressure and temperature logs gave bottom-hole temperatures ranging from 163 to 166{degree} C. During injection testing, downhole pressures were measured using capillary tubing with a surface quartz transducer while temperatures were measured with a Kuster temperature tool located below the capillary tubing pressure chamber. No pressure increase was measured at reservoir depths in any of the three slim holes while injecting 11 kg/s of 29{degree}C water indicating a very high permeability in the geothermal reservoir. These injection test results suggested that productive geothermal fluids could be found at depths sufficient for well pumping equipment and at temperatures needed for electrical power production using binary-type conversion technology.

  9. Geological characteristics of the peat deposits in Costa Rica (preliminary study)

    Energy Technology Data Exchange (ETDEWEB)

    Mora, S.; Cohen, A.D.; Raymond, R.; Alvarado, A.; Malavassi, L.

    1986-04-01

    Wide areas containing peat deposits have been found in Costa Rica. Three of them were selected for the preliminary evaluation. In the Talamanca range peat occurs as a thin blanket deposit about 1 m thick in an area of about 150 km/sup 2/. It is very decomposed (about 28% fibers), with high ash content, (21%) and extensively bioturbated. It has the lowest water content (84%), pH, fixed carbon (23%) and sulphur (0.2%) of all the sampled sites, However, it has the highest bulk density (0.22 g/cm/sup 3/) and volatile components (55%). Its calorific value averages 7700 Btu/lb, dry. In Medio Queso de Upala, several peat horizons are interbedded with alluvium layers within a 70 km/sup 2/ flood plain. They have the highest calorific values (8000 Btu/lb, dry), fixed carbon (30%) and ash content (22%). Their fiber content is low (27%), and the bulk density 0.20 g/cm/sup 3/. In El Silencio, near Siquirres, the thickness of the main layer exceeds 3.5 m, averaging 19% of ash, 53% of fibers, 5.8 pH, 0.6% of sulphur, 0.13 g/cm/sup 3/ bulk density, and 7500 Btu/lb, dry. (5 refs.)

  10. Hydrogeochemical and stream sediment reconnaissance basic data for Dodge City NTMS Quadrangle, Kansas

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-31

    Results of a reconnaissance geochemical survey of the Dodge City Quadrangle are reported. Field and laboratory data are presented for 756 groundwater and 321 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are displayed. A generalized geologic map of the survey area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. Groundwater data indicate that the most promising areas for uranium mineralization are as follows: (1) in the north central area of the quadrangle within close proximity to the Arkansas River, mostly from waters of the Ogallala Formation; (2) in the west central area, from groundwater samples of the Dakota and the Ogallala Formations; and (3) between the North Fork of the Cimarron River and the main Cimarron River, mostly in waters from the Ogallala Formation. Associated with the high uranium values are high concentrations for magnesium, strontium, and sulfate. Of the groundwater samples taken 81% were collected from the Ogallala Formation. Stream sediment data indicate high uranium concentrations in scattered samples in the northwestern, central, and southwestern areas of the quadrangle. Most of the samples with high uranium values were collected from the Quaternary alluvium. Associated with the high uranium values are high concentrations of barium, cerium, iron, manganese, titanium, vanadium, yttrium, and zirconium.

  11. Design and construction of tailings dams in Madagascar tropical wet conditions for the Ambatovy project

    Energy Technology Data Exchange (ETDEWEB)

    Afif, Muhammad; Chen, Ruijie; Iryo, Tatsuo [SNC-Lavalin Inc., Vancouver, (Canada); Penttinen, Stan [Sherritt Inc., Toronto, (Canada)

    2010-07-01

    The tailings management facility (TMF) of the Ambatovy Nickel Project is located on the east coast of Madagascar. The TMF required the construction of three embankments in the first project phase to meet tailing storage and water management requirements. It includes a starter dam of 33 m high and two smaller separator dams. The paper presented the design background, construction history and performance of the starter dam during and after its construction. The major constraints were the high tropical rainfall intensity, the high natural water content, the high plasticity of the residual soils used to construct the dam, and the lack of granular materials. The problem posed by the presence of up to about 3 m thick alluvium layer, comprising soft clay and loose sands, was solved by performing excavations to a competent stratum. Extensive field vane tests were performed to evaluate the soil characteristics. It was also found that the nuclear density meter was unreliable for the compaction control of the residual soils.

  12. Anthropogenic-Induced Changes in the Mechanism of Drylands Ephemeral Stream Recharge, Western Saudi Arabia

    KAUST Repository

    Jadoon, Khan

    2016-04-07

    Wadi aquifers in Saudi Arabia historically have been recharged primarily by channel loss (infiltration) during floods. Historically, seasonal groundwater levels fluctuated from land surface to about 3 m below the surface. Agricultural irrigation pumping has lowered the water table up to 35 m below the surface. The geology surrounding the fluvial system at Wadi Qidayd consists of pelitic Precambrian rocks that contribute sediments ranging in size from mud to boulders to the alluvium. Sediments within the wadi channel consist of fining upward, downstream-dipping beds, causing channel floodwaters to pass through several sediment sequences, including several mud layers, before it can reach the water table. Investigation of the wadi aquifer using field observation, geological characterization, water-level monitoring, geophysical profiles, and a hypothetical model suggests a critical water level has been reached that affects the recharge of the aquifer. The wetted front can no longer reach the water table due to the water uptake in the wetting process, downstream deflection by the clay layers, and re-emergence of water at the surface with subsequent direct and diffusive evaporative loss, and likely uptake by deep-rooted acacia trees. In many areas of the wadi system, recharge can now occur only along the channel perimeter via fractured rocks that are in direct horizontal hydraulic connection to the permeable beds above and below the water table.

  13. Completion Report for Well Cluster ER-6-1

    Energy Technology Data Exchange (ETDEWEB)

    Bechtel Nevada

    2004-10-01

    Well Cluster ER-6-1 was constructed for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Nevada Environmental Restoration Division at the Nevada Test Site, Nye County, Nevada. This work was initiated as part of the Groundwater Characterization Project, now known as the Underground Test Area Project. The well cluster is located in southeastern Yucca Flat. Detailed lithologic descriptions with stratigraphic assignments for Well Cluster ER-6-1 are included in this report. These are based on composite drill cuttings collected every 3 meters and conventional core samples taken below 639 meters, supplemented by geophysical log data. Detailed petrographic, chemical, and mineralogical studies of rock samples were conducted on 11 samples to resolve complex interrelationships between several of the Tertiary tuff units. Additionally, paleontological analyses by the U.S. Geological Survey confirmed the stratigraphic assignments below 539 meters within the Paleozoic sedimentary section. All three wells in the Well ER-6-1 cluster were drilled within the Quaternary and Tertiary alluvium section, the Tertiary volcanic section, and into the Paleozoic sedimentary section.

  14. Soil Erodibility for Water Pollution Management of Melaka Watershed in Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Md. Ibrahim Adham

    2015-07-01

    Full Text Available The relationships between surface runoffand soil erodibility are significant in water pollution and watershed management practices. Land use pattern, soil series and slope percentage are also major factors to develop the relationships. Daily rainfall data were collected and analyzed for variations in precipitation for calculating the surface runoff of these watersheds and surface runoff map was produced by GIS tools. Tew equation was utilized to predict soil erodibility of watershed soils.Results indicated that the weighted curve number varies from 82 to 85 and monthly runoff 23% to 30% among the five watersheds. Soil erodibility varies from 0.038 to 0.06 ton/ha (MJ.mm/ha/h. Linau-Telok-Local Alluvium, Malacca-Munchong, Munchong-Malacca-Serdang and Malacca-Munchong-Tavy are the dominant soil series of this region having the average soil erodibility of about 0.042 ton/ha (MJ.mm/ha/h. The main focus of this study is to provide the information of soil erodibility to reduce the water pollution of a watershed.

  15. Geoarchaeology and aggradation around Kinet Höyük, an archaeological mound in the Eastern Mediterranean, Turkey

    Science.gov (United States)

    Beach, Timothy P.; Luzzadder-Beach, Sheryl

    2008-10-01

    We examined the alluvial history of the plain near Kinet Höyük, an archaeological mound (or Tell) with a sequence of six millennia of occupation on the southeast Mediterranean coast of Turkey, through 17 excavations over a 1000 m transect near the Mound. Excavations ranged from 2 to 6 m deep and up to 20 m across. This low gradient, alluvial plain shows significantly different rates and processes of near-Mound sedimentation, with one unit having nearly 4 m of Late Bronze Age habitation and flood deposits and another having 4 m of Hellenistic channel and floodplain deposition. This flat, alluvial surface turns out to be a rich geoarchaeological landscape that shrouds Early and Late Bronze Age settlements, Hellenistic walls, and two epochs of Roman Roads. One widespread phenomenon was a Hellenistic or earlier paleosol and occupation level covered by channel gravels and overbank deposits mostly from the Hellenistic to the Late Roman period. These channel and floodplain deposits filled in and flattened out the off-Mound settlements, blanketing the Pre-Hellenistic topography and silting in a long active port. This glut of alluvium correlates in time with drier conditions and the most intensive land uses in the watershed, where Roman and Hellenistic sites today are severely eroded.

  16. Multimodel analysis of anisotropic diffusive tracer-gas transport in a deep arid unsaturated zone

    Science.gov (United States)

    Green, Christopher T.; Walvoord, Michelle Ann; Andraski, Brian J.; Striegl, Rob; Stonestrom, David A.

    2015-01-01

    Gas transport in the unsaturated zone affects contaminant flux and remediation, interpretation of groundwater travel times from atmospheric tracers, and mass budgets of environmentally important gases. Although unsaturated zone transport of gases is commonly treated as dominated by diffusion, the characteristics of transport in deep layered sediments remain uncertain. In this study, we use a multimodel approach to analyze results of a gas-tracer (SF6) test to clarify characteristics of gas transport in deep unsaturated alluvium. Thirty-five separate models with distinct diffusivity structures were calibrated to the tracer-test data and were compared on the basis of Akaike Information Criteria estimates of posterior model probability. Models included analytical and numerical solutions. Analytical models provided estimates of bulk-scale apparent diffusivities at the scale of tens of meters. Numerical models provided information on local-scale diffusivities and feasible lithological features producing the observed tracer breakthrough curves. The combined approaches indicate significant anisotropy of bulk-scale diffusivity, likely associated with high-diffusivity layers. Both approaches indicated that diffusivities in some intervals were greater than expected from standard models relating porosity to diffusivity. High apparent diffusivities and anisotropic diffusivity structures were consistent with previous observations at the study site of rapid lateral transport and limited vertical spreading of gas-phase contaminants. Additional processes such as advective oscillations may be involved. These results indicate that gases in deep, layered unsaturated zone sediments can spread laterally more quickly, and produce higher peak concentrations, than predicted by homogeneous, isotropic diffusion models.

  17. Tectonic controls on the geomorphic evolution of alluvial fans in the Piedmont Zone of Ganga Plain, Uttarakhand, India

    Indian Academy of Sciences (India)

    Pradeep K Goswami; Charu C Pant; Shefali Pandey

    2009-06-01

    The Piedmont Zone is the least studied part of the Ganga Plain.The northern limit of the Piedmont Zone is defined by the Himalayan Frontal Thrust (HFT)along which the Himalaya is being thrust over the alluvium of the Ganga Plain.Interpretation of satellite imagery,Digital Terrain Models (DTMs)and field data has helped in the identification and mapping of various morpho-tectonic features in the densely forested and cultivated Piedmont Zone in the Kumaun region of the Uttarakhand state of India.The Piedmont Zone has formed as a result of coalescing alluvial fans,alluvial aprons and talus deposits.The fans have differential morphologies and aggradation processes within a common climatic zone and similar litho-tectonic setting of the catchment area. Morphotectonic analysis reveals that the fan morphologies and aggradation processes in the area are mainly controlled by the ongoing tectonic activities.Such activities along the HFT and transverse faults have controlled the accommodation space by causing differential subsidence of the basin,and aggradation processes by causing channel migration,channel incision and shifting of depocentres.The active tectonic movements have further modified the landscape of the area in the form of tilted alluvial fan,gravel ridges,terraces and uplifted gravels.

  18. Dynamics of Mediterranean late Quaternary fluvial activity: An example from the River Ebro (north Iberian Peninsula)

    Science.gov (United States)

    Soria-Jáuregui, Ángel; González-Amuchástegui, María José; Mauz, Barbara; Lang, Andreas

    2016-09-01

    Late Pleistocene and Holocene fluvial evolution of the upper River Ebro (Miranda basin, north Spain) is analysed using geomorphological, sedimentological, and optical dating techniques. Maximum regional crustal uplift of 0.98 m/ka approximately helped preserve a suite of terraces in the Miranda basin: 5 river terraces (T1-5) were identified and their formation attributed to MIS 6 (T1), MIS 5d (T2), MIS 4 (T3), MIS 2 (T4), MIS 1 (T5). Alluvium deposited in terraces T1, T2, T3, and T4 is well-sorted, clast-supported gravels; whereas the T5 deposit is exclusively composed of silt. Gravels were deposited during cold and dry periods when reduced vegetation cover on hillslopes increased sediment supply to the trunk river. Silt was deposited in overbank settings under warmer and wetter climate conditions when vegetation cover stabilised hillslopes and restricted sediment supply. It also resulted in lower peak discharge and reduced flow velocities over vegetated floodplains. The chronological sequence of terraces indicates that incision occurred during climatic transitions. We conclude that the upper River Ebro responded to fluctuations in sediment supply and discharge controlled by late Quaternary climate cycles.

  19. River and groundwater level fluctuation analysis after barrage construction in riverside, South Korea

    Science.gov (United States)

    Baek, Keon Ha; Kim, Tae Hyung; Shin, Kyung Hee; Seom Bae, Jong

    2016-04-01

    Changes in river have brought to the change of groundwater hydrogeology and water quality. Also, the understanding of the interaction of groundwater and surface water is essential for the managing of effective water resource. In case of South Korea, there is increasing the interest of groundwater development and management in riverside through large river maintenance projects lately. The river water level was elevated than in the past and it is expected to the changes in the interaction between the existing groundwater and surface. This study analyzed the relationship between surrounding river water level and groundwater level in the 91 locations of groundwater observation wells, also was supposed to classify the similar pattern of groundwater by performing multivariate analysis. At the result of factor analysis, it is shown that the high and low factor in correlation between river water level and groundwater level were caused by receiving the significant external influence. In the result of cluster analysis, the middle and upper area of river were similar to the fluctuation pattern with river water level and groundwater level and the downstream area of river was shown with a low correlation. This is due to the characteristic showing a distribution of the alluvium in various types at the downstream area in compared to middle and upper area. In the future, the research is undergoing to analyze the time series of a point in time to account for the external influences of the effects on the groundwater level.

  20. Understanding groundwater systems and system responses to external stimulations through the long-term monitoring

    Science.gov (United States)

    Lee, J.; Park, D.; Piao, J.; Woo, N. C.

    2013-12-01

    A total of 335 monitoring stations (497 of monitoring wells), organized the National Groundwater Monitoring Network (NGMN), has been established at 117 watersheds in Korea since 1995, and water-level, temperature and electrical conductivity (EC) have been recorded by every hour to every six hours. Basically the monitoring stations are implemented with two wells for alluvium and bedrock aquifer at depths of 6.1 m and 71.6 m, respectively. Using these long-term monitoring data, we have tried to understand the groundwater systems in Korea and the system responses to external stimulations such as precipitation events, earthquakes, and groundwater over-exploitation. In this study, water-level, temperature and EC data were analyzed for the Han-river, Geum-river, Yeongsan-Seomjin-river and Nakdong-river basins, Korea, for the three years from 2010 to 2012. Precipitation data were obtained from the automatic weather systems of Korea Meteorological Administration (KMA) at the same period of time. These data will be used to assess the relationship between groundwater and precipitation using the Genetic Mapping Tools (GMT) and Fast Fourier Transform analysis, and to calculate the recharge rate each rainfall event. At each monitoring stations, groundwater system will be defined based on the water-level responses to precipitation events, and their response rate will be calculated for specific amount of precipitation. Later, these data will be used for the calculation of sustainability of the watershed for long-term water resource management.

  1. Rates of soil development from four soil chronosequences in the southern Great Basin

    Science.gov (United States)

    Harden, J.W.; Taylor, E.M.; Hill, C.; Mark, R.K.; McFadden, L.D.; Reheis, M.C.; Sowers, J.M.; Wells, S.G.

    1991-01-01

    Four soil chronosequences in the southern Great Basin were examined in order to study and quantify soil development during the Quaternary. Soils of all four areas are developed in gravelly alluvial fans in semiarid climates with 8 to 40 cm mean annual precipitation. Lithologies of alluvium are granite-gneiss at Silver Lake, granite and basalt at Cima Volcanic Field, limestone at Kyle Canyon, and siliceous volcanic rocks at Fortymile Wash. Ages of the soils are approximated from several radiometric and experimental techniques, and rates are assessed using a conservative mathematical approach. Average rates for Holocene soils at Silver Lake are about 10 times higher than for Pleistocene soils at Kyle Canyon and Fortymile Wash, based on limited age control. Holocene soils in all four areas appear to develop at similar rates, and Pleistocene soils at Kyle Canyon and Fortymile Wash may differ by only a factor of 2 to 4. Over time spans of several millennia, a preferred model for the age curves is not linear but may be exponential or parabolic, in which rates decrease with increasing age. These preliminary results imply that the geographical variation in rates within the southern Great Basin-Mojave region may be much less significant than temporal variation in rates of soil development. The reasons for temporal variation in rates and processes of soil development are complexly linked to climatic change and related changes in water and dust, erosional history, and internally driven chemical and physical processes. ?? 1991.

  2. Report on the radiochemical and environmental isotope character for monitoring well UE-1-q: Groundwater Characterization Program

    International Nuclear Information System (INIS)

    Well UE-1-q is located in the northeastern portion of area 1 of the Nevada Test Site in southwestern Nevada, 1244.1 meters above sea level. The well was originally an exploratory hole drilled to a depth of 743 meters below the surface (mbs) by LANL in November of 1980. In May 1992, the Groundwater Characterization Program (GCP) extended the total depth to approximately 792.5 mbs. UE-1-q is cased to a total depth of 749.5 mbs, with the remaining uncased depth exposed exclusively to Paleozoicaged carbonate rock, the principle zone of groundwater sampling. Geologic logging indicates approximately 390 meters of tuffaceous and calcareous alluvium overlies 320 meters of Tertiary-aged volcanic ash-flow and bedded tuffs. Paleozoic carbonate lithology extends from 716 mbs to the total well depth and is separated from the overlying Tertiary volcanic deposits by 6 meters of paleocolluvium. This report outlines the results and interpretations of radiochemical and environmental isotopic analyses of groundwater sampled from UE-1-q on July 10, 1992 during the well pump test following well development. In addition, results of the field tritium monitoring performed during the well drilling are reported in Appendix 1. Sampling, analytical techniques, and analytical uncertainties for the groundwater analyses are presented in Appendix 2

  3. Availability of fresh and slightly saline ground water in the basins of westernmost Texas

    Science.gov (United States)

    Gates, Joseph Spencer; Stanley, W.D.; Ackermann, H.D.

    1978-01-01

    Significant quantities of fresh ground water occur in the basin fill of the northern Hueco bolson and lower Mesilla Valley and in the Wildhorse Flat, Michigan Flat, Lobo Flat, and Ryan Flat areas of the Salt Basin; and may occur in Red Light Draw, Presidio bolson, and Green River valley. More than 20 million acre-feet of freshwater is estimated to be in storage in the basin fill of westernmost Texas. About 12 million acre-feet, or more than half, is in El Paso County in the Hueco bolson and Mesilla Valley. In addition, the basins contain about 7 million acre-feet of slightly saline water in basin fill, in Rio Grande alluvium in the Hueco bolson and lower Mesilla Valley, and in the Capitan Limestone in the northern Salt Basin. Ground-water pumping for municipal supply and industrial use in the El Paso area caused water-level declines of as much as 74 feet during 1903-73, and pumping for irrigation in the Salt Basin caused a maximum decline of 150 feet at Lobo Flat during 1949-73. Additional development of ground water in westernmost Texas will be accompanied by further declines in water levels, and will probably induce local migration of slightly saline or poorer quality water into freshwater areas. Land-surface subsidence could occur in local areas where water-level declines are large and the basin fill contains large amounts of compressible clay. (Kosco-USGS)

  4. Geophysical exploration for coal-bearing Gondwana basins in the states of West Bengal and Bihar in northeast India

    Energy Technology Data Exchange (ETDEWEB)

    Saha, S.N.; Roy, A.K.; Brahman, C.V.; Sastry, C.B.K.; De, M.K.

    1992-10-01

    The states of West Bengal and Bihar in northeast India are known to bear 'A' grade coal seams within Gondwana basins. An alluvium-covered area to the north of the Ajay river was considered to be prospective for the exploration of coal. Gravity and magnetic surveys were mainly carried out over an area of 1900 km[sup 2] with resistivity soundings taken at selected places. Gondwana sediments lying over basement subbasins are prospective areas for the exploration of coal. The gravity survey interpreted an 8-km wide and 20-km long depression known as the Pachami basin. This basin was drilled at several places and thick 'A' grade coal seams were intersected. The gravity survey broadly outlined the Pachami basin and several other basement depressions through gravity low contour closures. A forward modelling of a profile across the Pachami basin indicated a maximum depth of about 1.3 km to the basement at its deepest part. The magnetic map was vitiated through the presence of fluctuating high amplitude and high wavenumber anomalies due to a thick blanket of trap lying above the Gondwana sediments. Selected resistivity soundings could approximately interpret the shallow-basement depths, and the thickness and depths of the overlying trap.

  5. Application of electromagnetic techniques in survey of contaminated groundwater at an abandoned mine complex in southwestern Indiana, U.S.A

    International Nuclear Information System (INIS)

    In part of a large abandoned mining complex, electromagnetic geophysical surveys were used along with data derived from cores and monitoring wells to infer sources of contamination and subsurface hydrologic connections between acidic refuse deposits and adjacent undistributed geologic materials. Electrical resistivity increases sharply along the boundary of an elevated deposit of pyritic coarse refuse, which is highly contaminated and electrically conductive, indicating poor subsurface hydrologic connections with surrounding deposits of fine refuse and undisturbed glacial material. Groundwater chemistry, as reflected in values of specific conductance, also differs markedly across the deposit's boundary, indicating that a widespread contaminant plume has not developed around the coarse refuse in more than 40 yr since the deposit was created. Most acidic drainage from the coarse refuse is by surface and is concentrated around stream channels. Although most of the contaminated groundwater within the study area is concentrated within the surficial refuse deposits, transects of apparent resistivity and phase angle indicate the existence of an anomalous conductive layer at depth (> 4 m) in thick alluvial sediments along the northern boundary of the mining complex. Based on knowledge of local geology, the anomaly is interpreted to represent a subsurface connection between the alluvium and a flooded abandoned underground mine

  6. Investigations of the Fundamental Surface Reactions Involved in the Sorption and Desorption of Radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Czerwinski, Ken; Heske, Clemens; Moser, Duane; Misra, Mnoranjan; McMillion, Glen

    2011-04-20

    Models for describing solution- and surface-phase reactions have been used for 30 years, but only recently applicable to complex surfaces. Duff et al., using micro-XANES, found that Pu was concentrated on Mn-oxide and smectite phases of zeolitic tuff, providing an evaluation of contaminant speciation on surfaces for modeling. Experiments at Los Alamos demonstrated that actinides display varying surface residence time distributions, probably reflective of mineral surface heterogeneity. We propose to investigate the sorption/desorption behavior of radionuclides from mineral surfaces, as effected by microorganisms, employing isolates from Nevada Test Site deep alluvium as a model system. Characterizations will include surface area, particle size distribution, x-ray diffraction (XRD), microprobe analysis, extractions, and microbiology. Surface interactions will be assessed by electron spectroscopy (XPS), x-ray absorption fine structure spectroscopy (XAFS), X-ray emission spectroscopy, transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). Desert Research Institute (DRI), University of Nevada, Reno (UNR), and University of Nevada, Las Vegas (UNLV) researchers will collaborate to enhance scientific infrastructure and the understanding of contaminant behavior on surfaces, with broader implications for the management of DOE sites.

  7. Significance of pCO2 values in determining carbonate chemistry in groundwater of Pondicherry region,India

    Institute of Scientific and Technical Information of China (English)

    S Chidambaram; M.V Prasanna; U Karmegam; C Singaraja; S Pethaperumal; R Manivannan; P Anandhan; K Tirumalesh

    2011-01-01

    The partial pressure of Carbon-Dioxide plays a significant role in the water chemistry.It reflects the geochemical process and relates to the saturation index (SI) of the Carbonate minerals.A total number of 98 samples were collected from layered sequential aquifers like Alluvium,Upper Cuddalore sandstone,Lower Cuddalore Sandstone and Cretaceous formations,during Pre-Monsoon and Post-Monsoon seasons.Chemical parameters of groundwater such as pH,EC,TDS,Na+,K+,Ca2+,Mg2+,Cl-,HCO-3,SO2-4,pO3-4 and H4SiO4 were determined.The study shows that an increase in the log pCO2 values during water-rock interaction which influences the process of mineral dissolution.Saturation index of the carbonate minerals like Calcite,Aragonite,Dolomite and Magnesite were derived and compared with the log pCO2 values.In both the seasons the decreasing log pCO2 increases the saturation index of most of the carbonate minerals studied.The saturation index of almost all carbonate minerals during both the seasons showed negative correlation irrespective of the formation.Log pCO2 also develops a negative correlation with pH in groundwater of the study area.

  8. Ground-water-quality assessment of the Central Oklahoma Aquifer, Oklahoma; geochemical and geohydrologic investigations

    Science.gov (United States)

    Parkhurst, D.L.; Christenson, S.C.; Breit, G.N.

    1993-01-01

    The National Water-Quality Assessment pilot project for the Central Oklahoma aquifer examined the chemical and isotopic composition of ground water, the abundances and textures of minerals in core samples, and water levels and hydraulic properties in the flow system to identify geochemical reactions occurring in the aquifer and rates and directions of ground-water flow. The aquifer underlies 3,000\\x11square miles of central Oklahoma and consists of Permian red beds, including parts of the Permian Garber Sandstone, Wellington Formation, and Chase, Council Grove, and Admire Groups, and Quaternary alluvium and terrace deposits. In the part of the Garber Sandstone and Wellington Formation that is not confined by the Permian Hennessey Group, calcium, magnesium, and bicarbonate are the dominant ions in ground water; in the confined part of the Garber Sandstone and Wellington Formation and in the Chase, Council Grove, and Admire Groups, sodium and bicarbonate are the dominant ions in ground water. Nearly all of the Central Oklahoma aquifer has an oxic or post-oxic environment as indicated by the large dissolved concentrations of oxygen, nitrate, arsenic (V), chromium (VI), selenium (VI), vanadium, and uranium. Sulfidic and methanic environments are virtually absent. Petrographic textures indicate dolomite, calcite, sodic plagioclase, potassium feldspars, chlorite, rock fragments, and micas are dissolving, and iron oxides, manganese oxides, kaolinite, and quartz are precipitating. Variations in the quantity of exchangeable sodium in clays indicate that cation exchange is occurring within the aquifer. Gypsum may dissolve locally within the aquifer, as indicated by ground water with large concentrations of sulfate, but gypsum was not observed in core samples. Rainwater is not a major source for most elements in ground water, but evapotranspiration could cause rainwater to be a significant source of potassium, sulfate, phosphate and nitrogen species. Brines derived from

  9. Provenance of alluvial fan deposits to constrain the mid-term offsets along a strike-slip active fault: the Elsinore fault in the Coyote Mountains, Imperial Valley, California.

    Science.gov (United States)

    Masana, Eulalia; Stepancikova, Petra; Rockwell, Thomas

    2013-04-01

    The lateral variation in rates along a fault and its constancy along time is a matter of discussion. To give light to this discussion, short, mid and long term offset distribution along a fault is needed. Many studies analyze the short-term offset distribution along a strike-slip fault that can be obtained by the analysis of offset features imprinted in the morphology of the near-fault area. We present an example on how to obtain the mid- to long-term offset values based on the composition of alluvial fans that are offset by the fault. The study area is on the southern tip of the Elsinore fault, which controls the mountain front of the Coyote Mountains (California). The Elsinore-Laguna Salada fault is part of the San Andreas fault (SAF) system, extending 250 km from the Los Angeles Basin southeastward into the Gulf of California, in Mexico. The slip-rate on the southern Elsinore fault is believed to be moderate based on recent InSAR observations, although a recent study near Fossil Canyon (southern Coyote Mountains) suggests a rate in the range of 1-2 mm/yr. For this study we processed the airborne LiDAR dataset (EarthScope Southern & Eastern California, SoCal) to map short to mid-term alluvial offsets. We reprocessed the point clouds to produce DEMs with 0.5m and 0.25m grids and we varied the insolation angles to illuminate the various fault strands and the offset features. We identified numerous offset features, such as rills, channel bars, channel walls, alluvial fans, beheaded channels and small erosional basins that varied in displacement from 1 to 350 m. For the mid- to long-term offsets of the alluvial fans we benefited from the diverse petrological composition of their sources. Moreover, we recognized that older alluvium, which is offset by greater amounts, is in some cases buried beneath younger alluvial fan deposits and separated by buried soils. To determine the source canyon of various alluvial elements, we quantified the clast assemblage of each source

  10. Terrestrial Cosmogenic-Nuclide Dating of Alluvial Fans in Death Valley, California

    Science.gov (United States)

    Machette, Michael N.; Slate, Janet L.; Phillips, Fred M.

    2008-01-01

    We have used terrestrial cosmogenic nuclides (TCN) to establish the age of some of the most extensive Quaternary alluvial fans in Death Valley, California. These intermediate-age alluvial fans are most extensive on the western side of the valley, where tectonic deformation is considerably less pronounced than on the eastern side of the valley. These fans are characterized by a relatively smooth, densely packed desert pavement formed by well-varnished (blackened) clasts. These surfaces have been mapped as the Q2 gravel by previous workers and as unit Qai (intermediate age) by us. However, the intermediate-age gravels probably contain multiple subunits, as evidenced by slight differences in morphologic expression, soil formation, and inset geomorphic relations. The TCN technique used herein sums the cosmogenic 36Cl in approximately 2.5-meter-deep profiles through soil and host alluvium, thus avoiding some of the problems associated with the more typical surface-exposure dating of boulders or smaller clasts. Our TCN 36Cl dating of 12 depth profiles indicates that these intermediate-age (Qai) alluvial fans range from about 100 to 40 kilo-annum (ka), with a mean age of about 70 ka. An alternative interpretation is that alluvial unit Qai was deposited in two discrete episodes from 90 to 80 ka and from 60 to 50 ka, before and after MIS (marine oxygen-isotope stage) 4 (respectively). Without an intermediate-age unit, such as MIS 4 lake deposits, we can neither disprove nor prove that Qai was deposited in two discrete intervals or over a longer range of time. Thus, in Death Valley, alluvial unit Qai largely brackets MIS 4, which is not associated with a deep phase of Lake Manly. These Qai fans extend to elevations of about -46 meters (150 feet below sea level) and have not been transgressed by Lake Manly, suggesting that MIS 4 or MIS 2 lakes were rather shallow in Death Valley, perhaps because they lacked inflow from surface runoff of the Sierra Nevada drainages through

  11. Inverse analysis for vertical additional force of shaft wall considering temperature effect%考虑温度效应的井壁竖向附加力反演分析

    Institute of Scientific and Technical Information of China (English)

    何朋立; 王在泉

    2013-01-01

    为了分析考虑温度应力后作用于深厚表土层立井井壁竖向附加力,建立了由于立井内、外壁温度差产生的温度自应力和径向膨胀受阻产生的温度应力解析式。基于井壁是由于竖向应力超过钢筋混凝土井壁极限抗压强度而发生破裂的事实,对作用于井壁上的温度荷载、自重、水平侧压力和竖向附加力在井壁内产生的竖向应力分量进行了分析,结果表明,竖向附加力是导致井壁破裂的最主要因素,温度应力也是诱发井壁破裂的重要因素。同时在考虑井壁温度应力和井壁破裂特征的基础上,利用井壁结构设计理论通过反演分析得到了地层疏水沉降时井壁承受的最大竖向附加力的数值,为新建井壁设计和已建成投产井壁的安全性评估提供重要参考依据。%In order to analyze the role of vertical additional force on the shaft wall under deep alluvium when considering temperature effect, the temperature stress analytical formula of shaft wall is established,included the temperature self stress produced by temperature difference between inside and outside wall and the temperature stress produced by radial expansion hindered. Based on the fact that the rupture of shaft wall in the deep alluvium is due to the vertical stress of the shaft wall exceeding the limit of the reinforced concrete strength, the vertical stress components in the shaft wall are analyzed, which are produced by the temperature load, dead weight, horizontal lateral pressure and vertical additional force. The results show that the vertical additional force is the most important factor to lead to shaft wall fracture and the temperature stress is also an important factor of shaft wall fracture. Considering the rupture characteristics of shaft wall, the maximum value of vertical additional force which is caused by the settlement of the strata drainage is gotten through inverse analysis based on shaft lining

  12. Sr isotope evolution during chemical weathering of granites -- impact of relative weathering rates of minerals

    Institute of Scientific and Technical Information of China (English)

    MA; Yingjun

    2001-01-01

    [1]Ma, Y. J., Liu, C. Q., Geochemistry of strontium isotopes in the crust weathering system, Acta Mineralogica Sinica (in Chinese), 1998, 18(3): 350.[2]Ma, Y. J., Liu, C. Q., Using strontium isotopes to trace nutrient element circulation and hydrochemical evolution within an ecosystem, Advance in Earth Sciences (in Chinese), 1999, 14 (4): 377.[3]Brantley, S. L., Chesley, J. T., Stillings, L. L., Isotopic ratios and release rates of strontium from weathering feldspars, Geochim. Cosmochim. Acta, 1998, 62(9): 1493.[4]Blum, J. D., Erel, Y., A silicate weathering mechanism linking increases in marine 87Sr/86Sr with global glaciation, Nature, 1995, 373: 415.[5]Blum, J. D., Erel, Y., Rb-Sr isotope systematics of granitic soil chronosequence: The importance of biotite weathering, Geochim. Cosmochim. Acta, 1997, 61(15): 3193.[6]Bullen, T., Krabbenhoft, D., Kendall, C., Kinetic and mineralogic controls on the evolution of groundwater chemistry and 87Sr/86Sr in a sandy silicate aquifer, northern Wisconsin, USA, Geochim. Cosmochim. Acta, 1996, 60: 1807.[7]Bullen, T., White, A., Blum, A. et al., Chemical weathering of a soil chronosequence on granitoid alluvium: Ⅱminer-alogic and isotopic constraints on the behavior of strontium, Geochim. Cosmochim. Acta, 1997, 61: 291.[8]Blum, J. D., Erel, Y., Brown, K., 87Sr/86Sr ratios of Sierra Nevada stream waters: Implications for relative mineral weath-ering rates, Geochim. Cosmochim. Acta, 1993, 57: 5019.[9]Ma Yingjun, Trace element and strontium isotope geochemistry during chemical weathering, Ph. D. Dissertation, 1999, Institute of Geochemistry, Chinese Academy of Sciences.[10]Nesbitt, H. W., Markovics, G., Price, R. C., Chemical processes affecting alkalis and alkaline earths during continental weathering, Geochim. Cosmochim. Acta, 1980, 44: 1659.[11]Clauer, N., Strontium and argon isotopes in naturally weathered biotites, muscovites and feldspars, Chem. Geol., 1981, 31: 325.[12

  13. Assessing the hydraulic connection between fresh water aquifers and unconventional gas production using methane and stable isotopes

    Science.gov (United States)

    Iverach, Charlotte P.; Cendón, Dioni I.; Hankin, Stuart I.; Lowry, Dave; Fisher, Rebecca E.; France, James L.; Nisbet, Euan G.; Baker, Andy; Kelly, Bryce F. J.

    2015-04-01

    Unconventional gas developments pose a risk to groundwater quality and quantity in adjacent or overlying aquifers. To manage these risks there is a need to measure the background concentration of indicator groundwater chemicals and to map pathways of hydraulic connectivity between aquifers. This study presents methane (CH4) concentration and isotopic composition, dissolved organic carbon concentration ([DOC]) and tritium (3H) activity data from an area of expanding coal seam gas (CSG) exploration and production (Condamine Catchment, south-east Queensland, Australia). The target formation for gas production within the Condamine Catchment is the Walloon Coal Measures (WCM). This is a 700 m thick, low-rank CSG resource, which consists of numerous thin discontinuous lenses of coal separated by very fine-to medium-grained sandstone, siltstone, and mudstone, with minor calcareous sandstone, impure limestone and ironstone. The thickness of the coal makes up less than 10% of the total thickness of the unit. The WCM are overlain by sandstone formations, which form part of the Great Artesian Basin (GAB). The Condamine Alluvium fills a paleo-valley carved through the above formations. A combination of groundwater and degassing air samples were collected from irrigation bores and government groundwater monitoring boreholes. Degassing air samples were collected using an SKC 222-2301 air pump, which pumped the gas into 3 L Tedlar bags. The groundwater was analysed for 3H and [DOC]. A mobile CH4 survey was undertaken to continuously sample air in and around areas of agricultural and unconventional gas production. The isotopic signature of gas from the WCM was determined by sampling gas that was off-gassing from a co-produced water holding pond as it was the largest emission that could be directly linked to the WCM. This was used to determine the source signature of the CH4 from the WCM. We used Keeling plots to identify the source signature of the gas sampled. For the borehole

  14. The Quaternary Silver Creek Fault Beneath the Santa Clara Valley, California

    Science.gov (United States)

    Wentworth, Carl M.; Williams, Robert A.; Jachens, Robert C.; Graymer, Russell W.; Stephenson, William J.

    2010-01-01

    The northwest-trending Silver Creek Fault is a 40-km-long strike-slip fault in the eastern Santa Clara Valley, California, that has exhibited different behaviors within a changing San Andreas Fault system over the past 10-15 Ma. Quaternary alluvium several hundred meters thick that buries the northern half of the Silver Creek Fault, and that has been sampled by drilling and imaged in a detailed seismic reflection profile, provides a record of the Quaternary history of the fault. We assemble evidence from areal geology, stratigraphy, paleomagnetics, ground-water hydrology, potential-field geophysics, and reflection and earthquake seismology to determine the long history of the fault in order to evaluate its current behavior. The fault formed in the Miocene more than 100 km to the southeast, as the southwestern fault in a 5-km-wide right step to the Hayward Fault, within which the 40-km-long Evergreen pull-apart basin formed. Later, this basin was obliquely cut by the newly recognized Mt. Misery Fault to form a more direct connection to the Hayward Fault, although continued growth of the basin was sufficient to accommodate at least some late Pliocene alluvium. Large offset along the San Andreas-Calaveras-Mt Misery-Hayward Faults carried the basin northwestward almost to its present position when, about 2 Ma, the fault system was reorganized. This led to near abandonment of the faults bounding the pull-apart basin in favor of right slip extending the Calaveras Fault farther north before stepping west to the Hayward Fault, as it does today. Despite these changes, the Silver Creek Fault experienced a further 200 m of dip slip in the early Quaternary, from which we infer an associated 1.6 km or so of right slip, based on the ratio of the 40-km length of the strike-slip fault to a 5-km depth of the Evergreen Basin. This dip slip ends at a mid-Quaternary unconformity, above which the upper 300 m of alluvial cover exhibits a structural sag at the fault that we interpret as

  15. Integrative geomorphological mapping approach for reconstructing meso-scale alluvial fan palaeoenvironments at Alborz southern foothill, Damghan basin, Iran

    Science.gov (United States)

    Büdel, Christian; Majid Padashi, Seyed; Baumhauer, Roland

    2013-04-01

    University of Würzburg performs additional geochronologic and stratigraphic studies of different alluvial surfaces in the investigation area. Relative and absolute dating methods are applied, as well as non-invasive and invasive methods for studying subsurface sedimentation and layering. The ongoing mapping work has revealed a progradational sequence of at least five more or less dissected surfaces of alluvial deposits. These can be distinguished by optically taken morphometric and spectrometric parameters and material reflectance using remote sensing imagery data. An important role for geomorphometric measurements and landform identification was occupied by DEM data. In the field these parameters could be correlated with differently developed covers of desert pavement, and changes in curvature, roughness and levels of sediment surfaces. The studied alluvium has been formed by several phases of debris flow activity and braided river dynamics over a distance of more than 3.5 km and is reworked recently. Gradual differences in structure and form may be linked to changes in depositional process and quaternary environmental development as well as neotectonic activity. Future correlation between alluvium and sediment cores from the playa is targeting on better understanding of depositional milieus during activity phases.

  16. Simulation of a long-term aquifer test conducted near the Rio Grande, Albuquerque, New Mexico

    Science.gov (United States)

    McAda, Douglas P.

    2001-01-01

    A long-term aquifer test was conducted near the Rio Grande in Albuquerque during January and February 1995 using 22 wells and piezometers at nine sites, with the City of Albuquerque Griegos 1 production well as the pumped well. Griegos 1 discharge averaged about 2,330 gallons per minute for 54.4 days. A three-dimensional finite-difference ground-water-flow model was used to estimate aquifer properties in the vicinity of the Griegos well field and the amount of infiltration induced into the aquifer system from the Rio Grande and riverside drains as a result of pumping during the test. The model was initially calibrated by trial-and-error adjustments of the aquifer properties. The model was recalibrated using a nonlinear least-squares regression technique. The aquifer system in the area includes the middle Tertiary to Quaternary Santa Fe Group and post-Santa Fe Group valley- and basin-fill deposits of the Albuquerque Basin. The Rio Grande and adjacent riverside drains are in hydraulic connection with the aquifer system. The hydraulic-conductivity values of the upper part of the Santa Fe Group resulting from the model calibrated by trial and error varied by zone in the model and ranged from 12 to 33 feet per day. The hydraulic conductivity of the inner-valley alluvium was 45 feet per day. The vertical to horizontal anisotropy ratio was 1:140. Specific storage was 4 x 10-6 per foot of aquifer thickness, and specific yield was 0.15 (dimensionless). The sum of squared errors between the observed and simulated drawdowns was 130 feet squared. Not all aquifer properties could be estimated using nonlinear regression because of model insensitivity to some aquifer properties at observation locations. Hydraulic conductivity of the inner-valley alluvium, middle part of the Santa Fe Group, and riverbed and riverside-drain bed and specific yield had low sensitivity values and therefore could not be estimated. Of the properties estimated, hydraulic conductivity of the upper part of

  17. Prospects for developing stock - Water supplies from wells in northeastern Garfield County, Montana

    Science.gov (United States)

    Van Lewen, M. C.; King, Norman Julius

    1971-01-01

    Ground-water resources in northeastern Garfield County, Mont., afford a practical and reliable source of stock water on the intermingled public and private grazing lands that together comprise an area of about 1,200 square miles. The oldest formation exposed in the area is the relatively thick and impermeable Bearpaw Shale of Cretaceous .age. Overlying the Bearpaw Shale in succession are the Fox Hills Sandstone and Hell Creek Formation of Cretaceous age, the Fort Union Formation of Tertiary age, and thin glacial deposits .and alluvium of Quaternary age. All but the Bearpaw Shale and the glacial deposits are potential aquifers. Published geologic maps were found to be satisfactory after fitting contacts to the topographic base. Mapping, therefore, was limited mainly to outlining on aerial photographs the alluvial deposits in the stream valleys. The major structural feature is the Blood Creek syncline, the axis of which plunges eastward 10-15 feet per mile across the southern part of the area. Beds generally dip 15-25 feet per mile toward the synclinal axis. Water in bedrock aquifers is under artesian pressure, .and most wells in Big and Little Dry Creek valleys flow at the land surface. The only bedrock aquifer having appreciable areal extent is a sandstone 30-70 feet thick that has been mapped by previous investigators as the upper part of the Fox Hills Sandstone. This aquifer crops out in the northern and northwestern parts of the area and dips about 20 feet per mile southeastward beneath younger beds. Most wells in the northern half of the area obtain water from this sandstone at drilling depths of less than 200 feet. The depth to the Fox Hills Sandstone increases progressively southward, and most wells south of Woody Creek obtain water from irregularly distributed sandstone beds and lenses in the overlying Hell Creek and Fort Union Formations. The depth at which water may be obtained from these beds is not accurately predictable, but the depth seldom exceeds 300

  18. Calcareous palaeosols and temples in the floodplain of Thebes, Egypt: droughts and decisions

    Science.gov (United States)

    Graham, Angus; Hunter, Morag A.; Pennington, Benjamin T.; Strutt, Kristian D.

    2014-05-01

    The Egypt Exploration Society Theban Harbours and Waterscapes Survey (THaWS) works in the area around modern Luxor (Egypt), and investigates the extent to which the Egyptians manipulated the Nile and floodplain through canal and basin construction. A current focus of the project is to understand the relationship between the floodplain and a series of temples on the West Bank. A longstanding puzzle on the West Bank is why the temple of Amenhotep III (1390-1352 BCE) is not located in the same area as all the others. While 19 kings of the Egyptian New Kingdom (1550-1070 BCE) built their temples on the toe-slope of the limestone cliffs fronting onto the edge of the modern alluvium, Amenhotep's sits entirely on the modern floodplain. Egyptologists have suggested this was done to allow the inundation of the Nile to wash into the temple, symbolising and recreating the essential Egyptian cosmogony of the primeval mound. However, was it possible that a period of low Nile discharge enabled him to build on the alluvium whilst keeping the temple dry from the Nile floods? The project is testing this hypothesis through an interdisciplinary approach which provides focussed information on the development of the floodplain over historic time periods. It combines geophysical survey (Electrical Resistivity Tomography, Ground Penetrating Radar and magnetometry) with geoarchaeology using an Eijkelkamp hand auger and gouge auger with facies being dated using the stratigraphic sequence of ceramic fragments within them. Two fieldwork seasons have been carried out to date (Graham et al. 2012, 2013). Calcareous palaeosols c. 4m below the surface have been identified in three separate augers across a distance of 3 km on the West Bank floodplain, suggesting a period of low inundation levels / drought. At one of the locations an ancient surface appears to lie 0.3-0.4m above the calcisol. Ceramic fragments from this unit tentatively indicate a New Kingdom date. The strontium isotope record from

  19. Contribution of the airborne geophysical survey to the study of the regolith : A case study in southern Paris Basin.

    Science.gov (United States)

    Prognon, Francois; Lacquement, Fréderic; Deparis, Jacques; Martelet, Guillaume; Perrin, José

    2010-05-01

    , spectrometric data in the southern part of the region reveal a wide K-depleted area which is absolutely unexpected from the existing geological maps. Careful analysis of the available geological descriptions reveals that this geochemical signature is linked to the weathering, erosion and transport of specific source rock materials. In this context, K-depleted alluviums derive from clay with flint, (weathering product of the upper cretaceous chalk), whereas K-enriched alluviums are drainage products of the Loire River which were eroded in the Massif Central crystalline basement. In conclusion, spectrometric data allows the discrimination and cartography of new geochemical signatures. This new form of visualisation of the geology provides the opportunity to enrich our perception of the regolith and will necessitate an update of our methods of cartography. As briefly developed in this paper, outcomes are expected both for human environmental applications (better understanding of the centre France alluvial system dynamics) and for scientific geological understanding (basin geodynamic).

  20. Characterizing the Iron Wash fault: A fault line scarp in Utah

    Science.gov (United States)

    Kozaci, O.; Ostenaa, D.; Goodman, J.; Zellman, M.; Hoeft, J.; Sowers, J. M.; Retson, T.

    2015-12-01

    The Iron Wash fault (IWF) is an approximately 30 mile-long, NW-SE trending structure, oriented perpendicular to the San Rafael Monocline near Green River in Utah. IWF exhibits well-expressed geomorphic features such as a linear escarpment with consistently north side down displacement. The fault coincides with an abrupt change in San Rafael Monocline dip angle along its eastern margin. The IWF is exposed in incised drainages where Jurassic Navajo sandstone (oldest) and Lower Carmel Formation (old), are juxtaposed against Jurassic Entrada sandstone (younger) and Quaternary alluvium (youngest). To assess the recency of activity of the IWF we performed detailed geomorphic mapping and a paleoseismic trenching investigation. A benched trench was excavated across a Quaternary fluvial terrace remnant across the mapped trace of the IWF. The uppermost gravel units and overlying colluvium are exposed in the trench across the projection of the fault. In addition, we mapped the basal contact of the Quaternary gravel deposit in relation to the adjacent fault exposures in detail to show the geometry of the basal contact near and across the fault. We find no evidence of vertical displacement of these Quaternary gravels. A preliminary U-series date of calcite cementing unfaulted fluvial gravels and OSL dating of a sand lens within the unfaulted fluvial gravels yielded approximately 304,000 years and 78,000 years, respectively. These preliminary results of independent dating methods constrains the timing of last activity of the IWF to greater than 78,000 years before present suggesting that IWF not an active structure. Its distinct geomorphic expression is most likely the result of differential erosion, forming a fault-line scarp.

  1. Geological evidence of tsunamis and earthquakes at the Eastern Hellenic Arc: correlation with historical seismicity in the eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Gerassimos Papadopoulos

    2012-12-01

    Full Text Available Sedimentary stratigraphy determined by trenching in Dalaman, south-western Turkey, revealed three sand layers at a distance of approximately 240 m from the shoreline and at elevations of +0.30, +0.55 and +0.90 cm. Storm surge action does not explain the features of these deposits that show instead typical characteristics of tsunami deposition. The sand layers correlate with historical tsunamis generated by large earthquakes which ruptured the eastern Hellenic Arc and Trench in 1303, 1481 and 1741. Accelerator mass spectrometry 14C dating of a wood sample from layer II indicated deposition in AD 1473±46, which fits the 1481 event. From an estimated average alluvium deposition rate of approximately 0.13 cm/year, layers I and III were dated at 1322 and 1724, which may represent the large 1303 and 1741 tsunamis. The geological record of the 1303 key event is very poor; therefore, sand layer I perhaps represents an important geological signature of the 1303 tsunami. However, the strong tsunami reported to have been generated by the 1609 earthquake is missing from Dalaman stratigraphy: this underlines the sensitivity of tsunami geological signatures to various local factors. The 1303 earthquake ruptured the trench between the islands of Crete and Rhodes. For the earthquakes of 1481, 1609 and 1741 we suggested that they were very likely generated in the Rhodes Abyssal Plain where sea depths of up to approximately 4200 m, together with the thrust component of seismotectonics, favor tsunami generation. Sand dykes directed upwards from layer I to layer II indicated that the 1481 earthquake triggered liquefaction of sand layer I. The results substantially widen our knowledge about the historical earthquake and tsunami activity in the eastern Mediterranean basin.

  2. Simulation of Carbon-14 Migration Through a Thick Unsaturated Alluvial Basin Resulting from an Underground Nuclear Explosion

    Science.gov (United States)

    Martian, P.; Larentzos, J.

    2008-12-01

    Yucca Flat is one of several areas on the Nevada Test Site that was used for underground nuclear testing. Extensive testing performed in the unsaturated and saturated zones have resulted in groundwater contamination and surface subsidence craters in the vicinity of the underground test areas. Simulation of multiphase 14C transport through the thick Yucca Flat alluvial basin was performed to estimate the magnitude of radionuclide attenuation occurring within the unsaturated zone. Parameterization of the 14C transport in the multiphase flow and transport simulator (FEHM) was verified with experimental data collected from a large unsaturated soil column experiment. The experimental data included 14C as a radio-labeled bicarbonate solution, SF6 gas, and lithium bromide solution breakthroughs. Two representative simulation cases with working points located at shallow and deep depths relative to the water table were created to investigate the impact of subsidence crater-enhanced recharge, crater-playa areal extent, gas-phase partitioning, solid-phase partitioning, and a reduced permeability/porosity compressed zone created during the explosion on 14C transport. The representative shallow test had a detonation point located 175 m below land surface, and the deep test had a working point 435 m below land surface in a 500 m deep unsaturated zone. Carbon-14 transport is influenced by gas-phase diffusion and sorption within the alluvium. Gas-phase diffusion is an attenuation mechanism that transports 14C gas as 14CO2 throughout the unsaturated zone and exposes it to a large amount of soil moisture, resulting in dilute concentrations. The simulations indicated that the majority of the 14C inventory remains in the unsaturated zone over a 1,000-year time period after detonation because gas-phase diffusion moves the bulk of the 14C away from the higher recharge occurring in crater playas. Retardation also plays a role in slowing advective aqueous phase transport to the water

  3. Predicting the Surface Redistribution of Possibly Contaminated Tephra Deposits at the Yucca Mountain Repository Using Cesium-137

    Science.gov (United States)

    Harrington, C. D.; Whitney, J. W.; Ebert, K.

    2003-12-01

    In the event a volcanic eruption occurred through the proposed Yucca Mountain repository, Nevada, radioactive waste particles could be incorporated into the eruption products and deposited with the volcanic ash. The objective of this study was to predict the surface redistribution of the contaminated tephra deposits in order to evaluate how the critical group (located 20 km south of the repository within the Fortymile Wash drainage area) might be affected. We calculated the volume of material that has been eroded or deposited within the past ~50 years using cesium (Cs)-137. Radioactive Cs-137 was distributed worldwide as a result of atmospheric nuclear weapons tests during the 1950's, and has been used as an anthropogenic tracer. In most earlier cesium-137 studies, the investigated sites were either along several transects or on plots of a few dozen km2, whereas this study covers an area of >1500 km2. Fortymile Wash is an 800-km2 drainage basin that includes the entire eastern slope of Yucca Mountain and the Fortymile Wash alluvial fan; therefore, understanding the surface processes along Fortymile Wash are important to the volcanic-eruption consequence. To assess erosion rates on the Fortymile Wash fan, alluvium samples were analyzed for Cs-137 concentrations, for the vertical cesium profile down to ~10 cm depth, and for particle-size composition of the upper 3-5 cm. The results of Cs-137 concentrations in the samples from the upper fan indicate that the upper fan interstream divide areas have been eroding over the last 50+ years and have lost 1 cm to 2 cm of the upper soil horizon, mainly as the result of eolian processes.

  4. Site observational work plan for the UMTRA project site at Shiprock, New Mexico

    International Nuclear Information System (INIS)

    The site observational work plan (SOWP) for the Shiprock, New Mexico, Uranium Mill Tailings Remedial Action (UMTRA) Project Site is the initial document for developing site-specific activities to achieve regulatory compliance in the UMTRA Ground Water Project. The regulatory framework used to select the proposed ground water compliance strategies is presented along with a discussion of the relationship of this SOWP to other UMTRA Ground Water Project programmatic documents. The Shiprock site consists of two, interconnected hydrogeologic systems: the terrace system and the floodplain system. Separate compliance strategies are proposed for these two systems. The compliance strategy for the terrace aquifer is no remediation with the application of supplemental standards based on classification of the terrace aquifer as having Class III (limited-use) ground water. The compliance strategy for the floodplain aquifer is active remediation using a subsurface biological barrier. These strategies were selected by applying site-specific data to the compliance framework developed in the UMTRA Ground Water programmatic environmental impact statement (PEIS) (DOE, 1994a). The site conceptual model indicates that milling-related contamination has impacted the ground water in the terrace and floodplain aquifers. Ground water occurs in both aquifers in alluvium and in fractures in the underlying Cretaceous age Mancos Shale. A mound of ground water related to fluids from the milling operations is thought to exist in the terrace aquifer below the area where settling ponds were in use during the mill operations. Most of the water occurring in the floodplain aquifer is from recharge from the San Juan River

  5. Unsaturated Zone and Saturated Zone Transport Properties (U0100)

    International Nuclear Information System (INIS)

    This Analysis/Model Report (AMR) summarizes transport properties for the lower unsaturated zone hydrogeologic units and the saturated zone at Yucca Mountain and provides a summary of data from the Busted Butte Unsaturated Zone Transport Test (UZTT). The purpose of this report is to summarize the sorption and transport knowledge relevant to flow and transport in the units below Yucca Mountain and to provide backup documentation for the sorption parameters decided upon for each rock type. Because of the complexity of processes such as sorption, and because of the lack of direct data for many conditions that may be relevant for Yucca Mountain, data from systems outside of Yucca Mountain are also included. The data reported in this AMR will be used in Total System Performance Assessment (TSPA) calculations and as general scientific support for various Process Model Reports (PMRs) requiring knowledge of the transport properties of different materials. This report provides, but is not limited to, sorption coefficients and other relevant thermodynamic and transport properties for the radioisotopes of concern, especially neptunium (Np), plutonium (Pu), Uranium (U), technetium (Tc), iodine (I), and selenium (Se). The unsaturated-zone (UZ) transport properties in the vitric Calico Hills (CHv) are discussed, as are colloidal transport data based on the Busted Butte UZTT, the saturated tuff, and alluvium. These values were determined through expert elicitation, direct measurements, and data analysis. The transport parameters include information on interactions of the fractures and matrix. In addition, core matrix permeability data from the Busted Butte UZTT are summarized by both percent alteration and dispersion

  6. Delineating Bukit Bunuh impact crater boundary by geophysical and geotechnical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Azwin, I. N., E-mail: nurazwinismail@yahoo.com; Rosli, S.; Nordiana, M. M.; Ragu, R. R.; Mark, J. [Geophysics Section, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Mokhtar, S. [Centre for Global Archaeological Research Malaysia, 11800 USM, Penang (Malaysia)

    2015-03-30

    Evidences of crater morphology and shock metamorphism in Bukit Bunuh, Lenggong, Malaysia were found during the archaeological research conducted by the Centre for Global Archaeological Research Malaysia, Universiti Sains Malaysia. In order to register Bukit Bunuh as one of the world meteorite impact site, detailed studies are needed to verify the boundary of the crater accordingly. Geophysical study was conducted utilising the seismic refraction and 2-D electrical resistivity method. Seismic refraction survey was done using ABEM MK8 24 channel seismograph with 14Hz geophones and 40kg weight drop while 2-D electrical resistivity survey was performed using ABEM SAS4000 Terrameter and ES10-64C electrode selector with pole-dipole array. Bedrock depths were digitized from the sections obtained. The produced bedrock topography map shows that there is low bedrock level circulated by high elevated bedrock and interpreted as crater and rim respectively with diameter approximately 8km. There are also few spots of high elevated bedrock appear at the centre of the crater which interpreted as rebounds zone. Generally, the research area is divided into two layers where the first layer with velocity 400-1100 m/s and resistivity value of 10-800 Om predominantly consists of alluvium mix with gravel and boulders. Second layer represents granitic bedrock with depth of 5-50m having velocity >2100 m/s and resistivity value of >1500 Om. This research is strengthen by good correlation between geophysical data and geotechnical borehole records executed inside and outside of the crater, on the rim, as well as at the rebound area.

  7. Fugitive Mercury Emissions From Nevada Gold Mines

    Science.gov (United States)

    Miller, M. B.; Eckley, C. S.; Gustin, M.; Marsik, F.

    2008-12-01

    Mercury (Hg) can be released from point sources at gold mines (e.g. stacks associated with ore processing facilities) as well as from diffuse fugitive sources (e.g. waste rock dumps, heap leaches, etc). Fugitive Hg emissions have not been quantified for active gold mines and as such a large knowledge gap exists concerning the magnitude of total emissions from this source type. This study measured fugitive Hg emissions from two active gold mines in Northern Nevada. To contextualize the magnitude of the mine emissions with respect to those associated with natural surfaces, data were collected from undisturbed areas near the mines that are of similar geologic character. The initial results from this project have shown that there is a large range in surface Hg concentrations and associated emissions to the atmosphere from different surface types within a mine as well as between the two mines. At both mines, the lowest surface Hg concentrations and emissions were associated with the alluvium/overburden waste rock dumps. Surface Hg concentrations and emissions at nearby undisturbed sites were of similar magnitude. Surface concentrations and emissions were substantially higher from active heap leaches. In addition to the difference in fluxes for specific materials, measured emissions must be put within the context of material spatial extent and temporal variability. Here we compare Hg emission contributions from mining and undisturbed materials as a function of space and time (diel and seasonal), and illustrate the need for collection of these types of data in order to reduce uncertainties in understanding air-surface Hg exchange.

  8. A stratigraphic model to support remediation of groundwater contamination in the southern San Francisco Bay area

    International Nuclear Information System (INIS)

    Some early regional studies in the southern San Francisco Bay Area applied the term 'older bay mud' to Wisconsin and older deposits thought to be estuarine in origin. This outdated interpretation has apparently contributed to an expectation of laterally-continuous aquifers and aquitards. In fact, heterogeneous alluvial deposits often create complex hydrogeologic settings that defy simple remedial approaches. A more useful stratigraphic model provides a foundation for conducting site investigations and assessing the feasibility of remediation. A synthesis of recent regional studies and drilling results at one site on the southwest margin of the Bay indicate that the upper quaternary stratigraphy consists of four primary units in the upper 200 feet of sediments (oldest to youngest): (1) Illinoian glacial-age alluvium (an important groundwater source); (2) Sangamon interglacial-age deposits, which include fine-grained alluvial deposits and estuarine deposits equivalent to the Yerba Buena Mud (a regional confining layer); (3) Wisconsin glacial-age alluvial fan and floodplain deposits; and (4) Holocene interglacial-age sediments, which include fine-grained alluvial and estuarine deposits equivalent to the 'younger bay mud'. Remedial investigations generally focus on groundwater contamination in the Wisconsin and Holocene alluvial deposits. Detailed drilling results indicate that narrow sand and gravel channels occur in anastomosing patterns within a Wisconsin to Holocene floodplain sequence dominated by interchannel silts and clays. The identification of these small-scale high-permeability conduits is critical to understanding and predicting contaminant transport on a local scale. Discontinuous site-specific aquitards do not provide competent separation where stacked channels occur and the correlation of aquitards over even small distance is often tenuous at best

  9. Cyclic Sediment Trading Between Channel and River Bed Sediments

    Science.gov (United States)

    Haddadchi, A.

    2015-12-01

    Much of the previous work on sediment tracing has focused on determining either the initial sources of the sediment (soils derive from a particular rock type) or the erosion processes generating the sediment. However, alluvial stores can be both a source and sink for sediment transported by streams. Here geochemical and fallout radionuclide tracing of river-bed and alluvial sediments are used to determine the role of secondary sources, sediment stores, as potential sources of sediment leaving Emu Creek catchment, southeastern Queensland, Australia. Activity concentrations of 137Cs on the river sediments are consistent with channel erosion being the dominant source at all sites sampled along the river. To characterise the deposition and remobilisation cycles in the catchment, a novel geochemical tracing approach was used. Successive pockets of alluvium were treated as discrete sink terms within geochemical mixing models and their source contributions compared with those of river bed sediments collected adjacent to each alluvial pocket. Three different size fractions were examined; silts and clays (soil/rock type sources to river bed and alluvial sediments at each sampling site was identical for all three different size fractions, but varied along the stream. Combining these findings it is concluded that proximal alluvial stores dominated the supply of sediment to the river at each location, with this being particularly evident at the catchment outlet. Identical contribution of rock type sources to both river bed and alluvial pockets together with the dominant erosion being from channel banks indicates a high degree of 'trading' between the fluvial space and the alluvial space. Hence, management works aimed at primarily reducing the supply of sediments to the outlet of Emu Creek should focus on rehabilitation of channel banks in the lower catchment.

  10. ANTHROPOGENIC EFFECTS ON SOIL MICROMYCETES

    Directory of Open Access Journals (Sweden)

    Dragutin A. Đukić

    2007-09-01

    Full Text Available This paper is a synthesis of long-term investigations based on the effect of different (mineral and organic fertilisers, heavy metals, contaminated irrigation water, nitrification inhibitor and detergents on the dynamics of soil fungi number. The investigations were performed at the Microbiology Department and trial fields of the Faculty of Agronomy in Cacak on smonitza and alluvium soils in field and greenhouse conditions. Maize, wheat, barley and red clover were used as test plants in these studies. The quantitative composition of the fungi in the soils investigated was determined by the Czapek selective agar dilution method. The study results show that the number of soil fungi was dependent on the type and rate of agrochemicals used, on the growing season and the soil zone the samples were taken from for the analysis. Lower nitrogen fertiliser rates (80 and 120 kg?ha-1 and organic fertilisers stimulated the development of soil fungi, unlike the rate of 150 kg?ha- 1. Heavy metals, mercury and cadmium in particular, as well as high rates of the N-serve nitrification inhibitor inhibited the development of this group of soil microorganisms. Generally, the adverse effect of contaminated irrigation water on the soil fungi was recorded in both soil types, and particularly in the smonitza under red clover. Low detergent (Meril concentrations did not have any significant effect on this group of microorganisms. In this respect, it can be concluded that the soil fungi number dynamics can be used in monitoring soils polluted by different toxinogenic substances.

  11. Status of understanding of the saturated-zone ground-water flow system at Yucca Mountain, Nevada, as of 1995

    International Nuclear Information System (INIS)

    Yucca Mountain, which is being studied extensively because it is a potential site for a high-level radioactive-waste repository, consists of a thick sequence of volcanic rocks of Tertiary age that are underlain, at least to the southeast, by carbonate rocks of Paleozoic age. Stratigraphic units important to the hydrology of the area include the alluvium, pyroclastic rocks of Miocene age (the Timber Mountain Group; the Paintbrush Group; the Calico Hills Formation; the Crater Flat Group; the Lithic Ridge Tuff; and older tuffs, flows, and lavas beneath the Lithic Ridge Tuff), and sedimentary rocks of Paleozoic age. The saturated zone generally occurs in the Calico Hills Formation and stratigraphically lower units. The saturated zone is divided into three aquifers and two confining units. The flow system at Yucca Mountain is part of the Alkali Flat-Furnace Creek subbasin of the Death Valley groundwater basin. Variations in the gradients of the potentiometric surface provided the basis for subdividing the Yucca Mountain area into zones of: (1) large hydraulic gradient where potentiometric levels change at least 300 meters in a few kilometers; (2) moderate hydraulic gradient where potentiometric levels change about 45 meters in a few kilometers; and (3) small hydraulic gradient where potentiometric levels change only about 2 meters in several kilometers. Vertical hydraulic gradients were measured in only a few boreholes around Yucca Mountain; most boreholes had little change in potentiometric levels with depth. Limited hydraulic testing of boreholes in the Yucca Mountain area indicated that the range in transmissivity was more than 2 to 3 orders of magnitude in a particular hydrogeologic unit, and that the average values for the individual hydrogeologic units generally differed by about 1 order of magnitude. The upper volcanic aquifer seems to be the most permeable hydrogeologic unit, but this conclusion was based on exceedingly limited data

  12. Groundwater quality appraisal and its hydrochemical characterization in Ghaziabad (a region of indo-gangetic plain), Uttar Pradesh, India

    Science.gov (United States)

    Singh, Uday Veer; Abhishek, Amar; Singh, Kunwar P.; Dhakate, Ratnakar; Singh, Netra Pal

    2014-06-01

    India's growing population enhances great pressure on groundwater resources. The Ghaziabad region is located in the northern Indo-Gangetic alluvium plain of India. Increased population and industrial activities make it imperative to appraise the quality of groundwater system to ensure long-term sustainability of resources. A total number of 250 groundwater samples were collected in two different seasons, viz., pre-monsoon and post monsoon and analyzed for major physico-chemical parameters. Broad range and great standard deviation occurs for most parameters, indicating chemical composition of groundwater affected by process, including water-rock interaction and anthropogenic effect. Iron was found as predominant heavy metal in groundwater samples followed by copper and lead. An exceptional high concentration of Chromium was found in some locations. Industrial activities as chrome plating and wood preservative are the key source to metal pollution in Ghaziabad region. On the basis of classification the area water shows normal sulfate, chloride and bi-carbonate type, respectively. Base-exchange indices classified 76 % of the groundwater sources was the sodium-bicarbonate type. The meteoric genesis indices demonstrated that 80 % of groundwater sources belong to a shallow meteoric water percolation type. Chadha's diagram suggested that the hydro-chemical faces belong to the HCO3 - dominant Ca2+-Mg2+ type along with Cl--dominant Ca2+-Mg2+-type. There was no significant change in pollution parameters in the selected seasons. Comparison of groundwater quality with Indian standards proves that majority of water samples are suitable for irrigation purposes but not for drinking.

  13. Dense Seismic Recordings of Two Surface-Detonated Chemical Explosions

    Science.gov (United States)

    Koper, K. D.; Hale, J. M.; Burlacu, R.; Goddard, K. J.; Trow, A.; Linville, L. M.; Stein, J. R.; Drobeck, D.; Leidig, M.

    2015-12-01

    In the summer of 2015 two controlled chemical explosions were carried out near Dugway, Utah. The 2 June 2015 explosion consisted of 30,000 lbs of ammonium nitrate fuel oil (ANFO) and the 22 July 2015 explosion consisted of 60,000 lbs of ANFO. The explosion centroids were 1-2 m above the Earth's surface and both created significant craters in the soft desert alluvium. To better understand the seismic source associated with surface explosions, we deployed an array of wireless, three-component, short-period (5 Hz corner frequency) seismometers for several days around each shot. For the first explosion, 46 receivers were deployed in a "lollipop" geometry that had a sparse ring at a radius of 1 km, and a dense stem with 100 m spacing for distances of 0.5-4.5 km. For the second explosion, 48 receivers were deployed similarly, but with a dense ring spaced in azimuthal increments of 10 degrees at a distance of 1 km, and a sparse stem (~500 m spacing) that extended to a distance of nearly 6 km. A rich variety of phases were recorded including direct P waves, refracted and reflected P waves, nearly monochromatic air-coupled Rayleigh waves, normally dispersed fundamental mode Rayleigh waves (Rg), primary airblast arrivals, some secondary airblast arrivals, and possibly tertiary airblast arrivals. There is also evidence of converted S waves on the radial components and possibly direct S energy on the radial and transverse components, although the transverse energy does not always possess a simple, coherent move-out with distance, implying that it might have a scattering origin. To aid in the phase identification, especially of the apparent SH and Love energy, we are currently performing tau-p, f-k, and particle motion analysis.

  14. Paleohydrology of the southern Great Basin, with special reference to water table fluctuations beneath the Nevada Test Site during the late(?) Pleistocene

    Science.gov (United States)

    Winograd, Isaac Judah; Doty, Gene C.

    1980-01-01

    Knowledge of the magnitude of water-table rise during Pleistocene pluvial climates, and of the resultant shortening of groundwater flow path and reduction in unsaturated zone thickness, is mandatory for a technical evaluation of the Nevada Test Site (NTS) or other arid zone sites as repositories for high-level or transuranic radioactive wastes. The distribution of calcitic veins filling fractures in alluvium, and of tufa deposits between the Ash Meadows spring discharge area and the Nevada Test Site indicates that discharge from the regional Paleozoic carbonate aquifer during the Late( ) Pleistocene pluvial periods may have occurred at an altitude about 50 meters higher than at present and 14 kilometers northeast of Ash Meadows. Use of the underflow equation (relating discharge to transmissivity, aquifer width, and hydraulic gradient), and various assumptions regarding pluvial recharge, transmissivity, and altitude of groundwater base level, suggest possible rises in potentiometric level in the carbonate aquifer of about -90 meters beneath central Frenchman Flat. During Wisconsin time the rise probably did not exceed 30 meters. Water-level rises beneath Frenchman Flat during future pluvials are unlikely to exceed 30 meters and might even be 10 meters lower than modern levels. Neither the cited rise in potentiometric level in the regional carbonate aquifer, nor the shortened flow path during the Late( ) Pleistocene preclude utilization of the NTS as a repository for high-level or transuranic-element radioactive wastes provided other requisite conditions are met as this site. Deep water tables, attendant thick (up to several hundred meter) unsaturated zones, and long groundwater flow paths characterized the region during the Wisconsin Stage and probably throughout the Pleistocene Epoch and are likely to so characterize it during future glacial periods. (USGS)

  15. Summary of tectonic and structural evidence for stress orientation at the Nevada Test Site

    Science.gov (United States)

    Carr, Wilfred James

    1974-01-01

    A tectonic synthesis of the NTS (Nevada Test Site) region, when combined with seismic data and a few stress and strain measurements, suggests a tentative model for stress orientation. This model proposes that the NTS is undergoing extension in a N. 50 ? W.-S. 50 ? E. direction coincident with the minimum principal stress direction. The model is supported by (1) a tectonic similarity between a belt of NTS Quaternary faulting and part of the Nevada-California seismic belt, for which northwest-southeast extension has been suggested; (2) historic northeast- trending natural- and explosion-produced fractures in the NTS; (3) the virtual absence in the NTS of northwest-trending Quaternary faults; (4) the character of north-trending faults and basin configuration in the Yucca Flat area, which suggest a component of right-lateral displacement and post-10 m.y. (million year) oblique separation of the sides of the north-trending depression; (5) seismic evidence suggesting a north- to northwest-trending tension axis; (6) strain measurements, which indicate episodes of northwest-southeast extension within a net northeast-southwest compression; (7) a stress estimate based on tectonic cracking that indicates near-surface northwest-southeast-directed tension, and two stress measurements indicating an excess (tectonic) maximum principal compressive stress in a northeast-southwest direction at depths of about 1,000 feet (305 m); and (8) enlargement of some drill holes in Yucca Flat in a northwest-southeast direction. It is inferred that the stress episode resulting in the formation of deep alluvium-filled trenches began somewhere between 10 and possibly less than 4 m.y. ago in the NTS and is currently active. In the Walker Lane of western Nevada, crystallization of plutons associated with Miocene volcanism may have increased the competency and thickness of the crust and its ability to propagate stress, thereby modulating the frequency (spacing) of basin-range faults.

  16. Three-Dimensional Geologic Model of Glacial Outwash in Mclean County, Illinois, Based on Seismic Refraction Studies

    Directory of Open Access Journals (Sweden)

    Matthew Hartz

    2016-02-01

    Full Text Available Seven two-dimensional (2-D seismic refraction lines were used to determine the thickness and geometry of a valley train outwash deposit of the Quaternary Henry Formation near Heyworth in southern McLean County, Illinois. These refraction data were collected and processed in 2-D, then imported into a Petrel, a three-dimensional (3-D geological modeling software package. The 3-D geologic model was built using the velocity attribute of the seismic refraction data. The 3-D velocity model was then verified manually by moving a cross-section through the velocity model at 20 m increments. These selected data points were used to create 3-D horizons, surfaces, and contacts constraining the target Henry Formation from the overlying alluvium of the Cahokia Formation and the underlying Delavan Till. Results of the 3-D model show the Henry Formation outwash trends about S10°E, which is oblique to S55°W-trending modern Kickapoo Creek valley. The Henry Formation outwash is confined to the Kickapoo valley, and consists of well-stratified sand and gravel at that is as much as 25 m in thickness in the channel. The thickness of the Henry Formation in the terrace is 8–10 m. The Cahokia Formation is everywhere about 2 m in thickness. The Henry Formation here is interpreted to be deposited in a subglacial tunnel valley that was deposited about 20,000 years ago as the Laurentide ice sheet retreated from its maximum southerly extent.

  17. One Hundred Years of Land Use Change in an Iconic Young Volcanic Landscape

    Science.gov (United States)

    Safran, E. B.; Batdorff, K.; Cross, J.; Krome, T.; Hamilton, D.; Bernstein, A. W.

    2013-12-01

    In young basaltic terrain, land use patterns are constrained by soil-forming processes and the ability to retain water in near-surface substrate. Rapid population growth over the last two centuries and a relatively lengthy tradition of land cover mapping makes Mt. Fuji a prime location for investigating how such constraints play out quantitatively. Though often considered the iconic stratovolcano, Mt. Fuji has erupted primarily basalt, in both explosive and effusive eruptions. We digitized historical land use maps to document land use patterns in 1898 and 1990 and related these to topographic and geologic controls. The dominant land use transformations include a 75% reduction (by area) in grasslands, a 100% increase in coniferous forest, and a >250% increase in mixed broadleaf/coniferous forest. Though much less extensive in absolute terms, the area devoted to mulberry plantation declined by 75%, while the area devoted to tea plantations increased by 150%. Forest areas have mean slopes of 15-20 degrees, while agricultural areas (e.g., rice paddy, tea plantations, mulberry plantations) occur on slopes of <10 degrees. In 1898, 40-60% of bamboo forests, mulberry plantations, tea plantations, and rice paddies were grown on sediment deposits - e.g., terraces, lahar deposits, alluvium deposits. By 1990, 80% of the remaining mulberry plantations occurred on young volcanic deposits and 70% of tea plantations occurred on old volcanic deposits, while 65% of rice paddies still occurred on sediment deposits. This reflects a shifting hierarchy of priorities and a differentiation of cultivation strategies where sedimentary deposits, the most suitable for cultivation, are sparse.

  18. An assessment of the erodibility of Holocene lithounits comprising streambanks in northeastern Kansas, USA

    Science.gov (United States)

    Layzell, Anthony L.; Mandel, Rolfe D.

    2014-05-01

    Streambanks are the primary source of sediment for watersheds in the Midwestern USA. In much of this region, deposits of fine-grained Holocene alluvium comprising streambanks have been assigned to a single lithostratigraphic unit, the DeForest Formation. This study examines the stratigraphic relationships and measures the erodibility of the different members of the DeForest Formation in three watersheds in northeastern Kansas. Distinct differences in erodibility, measured in terms of critical shear stress (τc) by a submerged jet-test device, were observed between the different members of the DeForest Formation. The most erodible member is the Camp Creek Member (average τc = 1.0 Pa) while the most resistant is the Gunder Member (average τc = 10.4 Pa). Variability in erodibility between and within the members of the DeForest Formation is attributed to the magnitude of post-depositional soil-forming processes, including the presence of buried soils, as well as the inherent natural variability in the different parent materials. A weak positive correlation was found between percent clay and τc. Resistance to erosion by fluid flow was found to be significantly greater where clay contents exceed 28%. Although the Camp Creek Member was found to be the most erodible, it always occurs, stratigraphically, as the uppermost member. Available bankfull stage indicators suggest that bankfull discharges rarely attain elevations sufficient to erode Camp Creek Member deposits. Therefore, other members of the DeForest Formation are able to exert some control on the rate of bank erosion by hydraulic flow. Furthermore, given the observed differences in lithology, soil development and erodibility, the susceptibility to mass wasting processes is also likely to vary between the different members. Therefore, lithostratigraphic and soil-stratigraphic relationships have important implications for streambank erodibility and are crucial for accurately determining areas prone to streambank

  19. Explaining nitrate pollution pressure on the groundwater resource in Kinshasa using a multivariate statistical modelling approach

    Science.gov (United States)

    Mfumu Kihumba, Antoine; Vanclooster, Marnik

    2013-04-01

    Drinking water in Kinshasa, the capital of the Democratic Republic of Congo, is provided by extracting groundwater from the local aquifer, particularly in peripheral areas. The exploited groundwater body is mainly unconfined and located within a continuous detrital aquifer, primarily composed of sedimentary formations. However, the aquifer is subjected to an increasing threat of anthropogenic pollution pressure. Understanding the detailed origin of this pollution pressure is important for sustainable drinking water management in Kinshasa. The present study aims to explain the observed nitrate pollution problem, nitrate being considered as a good tracer for other pollution threats. The analysis is made in terms of physical attributes that are readily available using a statistical modelling approach. For the nitrate data, use was made of a historical groundwater quality assessment study, for which the data were re-analysed. The physical attributes are related to the topography, land use, geology and hydrogeology of the region. Prior to the statistical modelling, intrinsic and specific vulnerability for nitrate pollution was assessed. This vulnerability assessment showed that the alluvium area in the northern part of the region is the most vulnerable area. This area consists of urban land use with poor sanitation. Re-analysis of the nitrate pollution data demonstrated that the spatial variability of nitrate concentrations in the groundwater body is high, and coherent with the fragmented land use of the region and the intrinsic and specific vulnerability maps. For the statistical modeling use was made of multiple regression and regression tree analysis. The results demonstrated the significant impact of land use variables on the Kinshasa groundwater nitrate pollution and the need for a detailed delineation of groundwater capture zones around the monitoring stations. Key words: Groundwater , Isotopic, Kinshasa, Modelling, Pollution, Physico-chemical.

  20. Chronicle of Bukit Bunuh for possible complex impact crater by 2-D resistivity imaging (2-DERI) with geotechnical borehole records

    Science.gov (United States)

    Jinmin, M.; Saad, R.; Saidin, M.; Ismail, N. A.

    2015-03-01

    A 2-D resistivity imaging (2-DERI) study was conducted at Bukit Bunuh, Lenggong, Perak. Archaeological Global Research Centre, Universiti Sains Malaysia shows the field evidence of shock metamorphisms (suevite breccia) and crater morphology at Bukit Bunuh. A regional 2-DERI study focusing at Bukit Bunuh to identify the features of subsurface and detail study was then executed to verify boundary of the crater with the rebound effects at Bukit Bunuh which covered approximately 132.25 km2. 2-DERI survey used resistivity equipment by ABEM SAS4000 Terrameter and ES10-64C electrode slector with pole-dipole array. The survey lines were carried out using `roll-along' technique. The data were processed and analysed using RES2DINV, Excel and Surfer software to obtain resistivity results for qualitative interpretations. Bedrock depths were digitized from section by sections obtained. 2-DERI results gives both regional and detail study shows that the study area was divided into two main zones, overburden consists of alluvium mix with boulders embedded with resistivity value of 10-800 Ωm and granitic bedrock with resistivity value of >1500 Ωm and depth 5-50 m. The low level bedrock was circulated by high level bedrock (crater rim) was formed at the same area with few spots of high level bedrock which appeared at the centre of the rim which suspected as rebound zones (R). Assimilations of 2-DERI with boreholes are successful give valid and reliable results. The results of the study indicates geophysical method are capable to retrieve evidence of meteorite impact subsurface of the studied area.

  1. Delineating Bukit Bunuh impact crater boundary by geophysical and geotechnical investigation

    Science.gov (United States)

    Azwin, I. N.; Rosli, S.; Mokhtar, S.; Nordiana, M. M.; Ragu, R. R.; Mark, J.

    2015-03-01

    Evidences of crater morphology and shock metamorphism in Bukit Bunuh, Lenggong, Malaysia were found during the archaeological research conducted by the Centre for Global Archaeological Research Malaysia, Universiti Sains Malaysia. In order to register Bukit Bunuh as one of the world meteorite impact site, detailed studies are needed to verify the boundary of the crater accordingly. Geophysical study was conducted utilising the seismic refraction and 2-D electrical resistivity method. Seismic refraction survey was done using ABEM MK8 24 channel seismograph with 14Hz geophones and 40kg weight drop while 2-D electrical resistivity survey was performed using ABEM SAS4000 Terrameter and ES10-64C electrode selector with pole-dipole array. Bedrock depths were digitized from the sections obtained. The produced bedrock topography map shows that there is low bedrock level circulated by high elevated bedrock and interpreted as crater and rim respectively with diameter approximately 8km. There are also few spots of high elevated bedrock appear at the centre of the crater which interpreted as rebounds zone. Generally, the research area is divided into two layers where the first layer with velocity 400-1100 m/s and resistivity value of 10-800 Om predominantly consists of alluvium mix with gravel and boulders. Second layer represents granitic bedrock with depth of 5-50m having velocity >2100 m/s and resistivity value of >1500 Om. This research is strengthen by good correlation between geophysical data and geotechnical borehole records executed inside and outside of the crater, on the rim, as well as at the rebound area.

  2. Shear-wave velocity characterization of the USGS Hawaiian strong-motion network on the Island of Hawaii and development of an NEHRP site-class map

    Science.gov (United States)

    Wong, I.G.; Stokoe, K.H., II; Cox, B.R.; Yuan, J.; Knudsen, K.-L.; Terra, F.; Okubo, P.; Lin, Y.-C.

    2011-01-01

    To assess the level and nature of ground shaking in Hawaii for the purposes of earthquake hazard mitigation and seismic design, empirical groundmotion prediction models are desired. To develop such empirical relationships, knowledge of the subsurface site conditions beneath strong-motion stations is critical. Thus, as a first step to develop ground-motion prediction models for Hawaii, spectralanalysis-of-surface-waves (SASW) profiling was performed at the 22 free-field U.S. Geological Survey (USGS) strong-motion sites on the Big Island to obtain shear-wave velocity (VS) data. Nineteen of these stations recorded the 2006 Kiholo Bay moment magnitude (M) 6.7 earthquake, and 17 stations recorded the triggered M 6.0 Mahukona earthquake. VS profiling was performed to reach depths of more than 100 ft. Most of the USGS stations are situated on sites underlain by basalt, based on surficial geologic maps. However, the sites have varying degrees of weathering and soil development. The remaining strong-motion stations are located on alluvium or volcanic ash. VS30 (average VS in the top 30 m) values for the stations on basalt ranged from 906 to 1908 ft/s [National Earthquake Hazards Reduction Program (NEHRP) site classes C and D], because most sites were covered with soil of variable thickness. Based on these data, an NEHRP site-class map was developed for the Big Island. These new VS data will be a significant input into an update of the USGS statewide hazard maps and to the operation of ShakeMap on the island of Hawaii.

  3. Stratigraphy and structure of the McCoy geothermal prospect, Churchill and Lander Counties, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Adams, M.C.

    1982-06-01

    The McCoy geothermal system straddles the border of Lander and Churchill counties, central Nevada, in the middle of the Basin and Range Province. The study area occupies approximately 100 sq. km. near the intersection of the Augusta and Clan Alpine Mountains and the New Pass Range. The geology of the area is dominated by rhyolite ash-flow tuffs and subordinate intermediate-composition lava flows of Oligocene age. These volcanics were emplaced on Permo-Pennsylvanian massive cherts and Triassic dolomitic limestones. At least two episodes of hydrothermal activity can be recognized at McCoy. The oldest event altered and mineralized the volcanic and sedimentary rocks, producing the McCoy and Wild Horse mercury deposits. The youngest event produced travertine and siliceous sinter deposits which intercalate with alluvium, and appears to be related to the high heat flow found at the McCoy prospect. The oldest recognized faults at McCoy produced several east-west grabens and horsts. These fault zones were active before and during the deposition of the volcanics. The Wild Horse and McCoy mercury mines occur along one of these east-west fault zones. Basin and Range faulting began subsequent to 23 m.y. ago, and produced a complex array of polygonal blocks which were subsequently eroded into subparallel cuestas. Fluid movement in the geothermal system is controlled by the intersections of the east-west and north-south faults. There is no known igneous source for the thermal energy in this system. However, its intramontane location is atypical of known geothermal systems in the Basin and Range, which may preclude deep circulation through major basin-bounding faults.

  4. From deposition to erosion: spatial and temporal variability of sediment sources, storage, and transport in a small agricultural watershed

    Science.gov (United States)

    Florsheim, J.L.; Pellerin, B.A.; Oh, N.H.; Ohara, N.; Bachand, P.A.M.; Bachand, Sandra M.; Bergamaschi, B.A.; Hernes, P.J.; Kavvas, M.L.

    2011-01-01

    The spatial and temporal variability of sediment sources, storage, and transport were investigated in a small agricultural watershed draining the Coast Ranges and Sacramento Valley in central California. Results of field, laboratory, and historical data analysis in the Willow Slough fluvial system document changes that transformed a transport-limited depositional system to an effective erosion and transport system, despite a large sediment supply. These changes were caused by a combination of factors: (i) an increase in transport capacity, and (ii) hydrologic alteration. Alteration of the riparian zone and drainage network pattern during the past ~ 150 years included a twofold increase in straightened channel segments along with a baselevel change from excavation that increased slope, and increased sediment transport capacity by ~ 7%. Hydrologic alteration from irrigation water contributions also increased transport capacity, by extending the period with potential for sediment transport and erosion by ~ 6 months/year. Field measurements document Quaternary Alluvium as a modern source of fine sediment with grain size distributions characterized by 5 to 40% fine material. About 60% of an upland and 30% of a lowland study reach incised into this deposit exhibit bank erosion. During this study, the wet 2006 and relatively dry 2007 water years exhibited a range of total annual suspended sediment load spanning two orders of magnitude: ~ 108,500 kg/km2/year during 2006 and 5,950 kg/km2/year during 2007, only 5% of that during the previous year. Regional implications of this work are illustrated by the potential for a small tributary such as Willow Slough to contribute sediment – whereas large dams limit sediment supply from larger tributaries – to the Sacramento River and San Francisco Bay Delta and Estuary. This work is relevant to lowland agricultural river–floodplain systems globally in efforts to restore aquatic and riparian functions and where water quality

  5. Unsaturated Zone and Saturated Zone Transport Properties (U0100)

    Energy Technology Data Exchange (ETDEWEB)

    J. Conca

    2000-12-20

    This Analysis/Model Report (AMR) summarizes transport properties for the lower unsaturated zone hydrogeologic units and the saturated zone at Yucca Mountain and provides a summary of data from the Busted Butte Unsaturated Zone Transport Test (UZTT). The purpose of this report is to summarize the sorption and transport knowledge relevant to flow and transport in the units below Yucca Mountain and to provide backup documentation for the sorption parameters decided upon for each rock type. Because of the complexity of processes such as sorption, and because of the lack of direct data for many conditions that may be relevant for Yucca Mountain, data from systems outside of Yucca Mountain are also included. The data reported in this AMR will be used in Total System Performance Assessment (TSPA) calculations and as general scientific support for various Process Model Reports (PMRs) requiring knowledge of the transport properties of different materials. This report provides, but is not limited to, sorption coefficients and other relevant thermodynamic and transport properties for the radioisotopes of concern, especially neptunium (Np), plutonium (Pu), Uranium (U), technetium (Tc), iodine (I), and selenium (Se). The unsaturated-zone (UZ) transport properties in the vitric Calico Hills (CHv) are discussed, as are colloidal transport data based on the Busted Butte UZTT, the saturated tuff, and alluvium. These values were determined through expert elicitation, direct measurements, and data analysis. The transport parameters include information on interactions of the fractures and matrix. In addition, core matrix permeability data from the Busted Butte UZTT are summarized by both percent alteration and dispersion.

  6. Archaeological investigations on the Buckboard Mesa Road Project

    Energy Technology Data Exchange (ETDEWEB)

    Amick, D.S.; Henton, G.H.; Pippin, L.C.

    1991-10-01

    In 1986, the Desert Research Institute (DRI) conducted an archaeological reconnaissance of a new alignment for the Buckboard Mesa Road on the Nevada Test Site for the Department of Energy (DOE). During this reconnaissance, several archaeological sites of National Register quality were discovered and recorded including a large quarry, site 26Ny4892, and a smaller lithic scatter, site 26Ny4894. Analysis of the debitage at 26Ny4892 indicates that this area was used primarily as a quarry for relatively small cobbles of obsidian found in the alluvium. Lithic reduction techniques used here are designed for efficiently reducing small pieces of toolstone and are oriented towards producing flake blanks from small cores and bifacially reducing exhausted cores. Projectile point cross references indicate that the area has seen at least casual use for about 10,000 years and more sustained use for the last 3,000 years. Initial obsidian hydration measurements indicate sustained use of the quarry for about the last 3,000 years although the loci of activities appear to change over time. Based on this study, the DRI recommends that quarrying activities in the area of 26Ny4892 are sufficiently sampled and that additional investigations into that aspect of prehistoric activity in the area are not necessary. This does not apply to other aspects of prehistoric use. DRI recommends that preconstruction surveys continue to identify nonquarrying, prehistoric utilization of the area. With the increased traffic on the Buckboard Mesa Road, there is a greater potential for vandalism to sites of National Register-quality located near the road. The DRI recommends that during the orientation briefing the workers at the Test Site be educated about the importance of cultural resources and the need for their protection. 202 refs., 41 figs., 52 tabs.

  7. Estimation of S-wave site response in and around Delhi region from weak motion data

    Indian Academy of Sciences (India)

    S K Nath; P Sengupta; S K Srivastav; S N Bhattacharya; R S Dattatrayam; R Prakash; H V Gupta

    2003-09-01

    Site response in and around Delhi is studied using digital seismograms recorded by a thirteen-station VSAT-based 24-bit digital Delhi telemetry network of the India Meteorological Department. Nine local (l ≥ 2.3) and nine regional (l ≥ 3.9) earthquakes are selected for the estimation of site amplification factor using the classical standard spectral ratio for regional events (Ridge Delhi Observatory being the reference station), normalized standard spectral ratio for local events, horizontal-to-vertical spectral ratio or receiver function and the generalized inversion techniques in the frequency range of 0.5 to 7.5 Hz. Site response curves at all the thirteen stations exhibit station to station variation of the site amplification factor reflecting the changes in geologic/geotectonic/soil conditions. A comparison of the site response values obtained by the generalized inversion with those computed using receiver function technique shows a large scatter even though the pattern of the curves remain more or less similar. However, the site effects computed by generalized inversion and standard spectral ratio exhibit a good 1:1 correspondence. The peaks yielded by all the methods have been observed to occur at the same frequencies. It is evident that the softer fluvial deposits of the newer alluvium of the east Yamuna sector show steeper site amplification gradient at lower frequencies, while the greater Delhi experiences moderate site amplification. The variation of site response corroborates the abrupt changes in intensity from one location to another due to local site condition.

  8. Legacy Morphologies: Channel Avulsions and Historical Engineering Structures Drive Form and Process in the Lower Yuba and Feather Rivers, California

    Science.gov (United States)

    James, L. A.; Singer, M. B.; Aalto, R.

    2008-12-01

    Geomorphic changes in the lower Yuba and Feather Rivers due to hydraulic mining provide a chance to study centennial-scale processes. Channel changes over 150 years were determined using channel-bank stratigraphy, geochemical signatures (total Hg, grain-size distributions, bulk geochemistry, fallout radionuclides, and Sr/Nd isotopes), and spatial analyses of high-resolution topographic data, historical maps, and aerial photos. Repeated avulsions and broad erosion/deposition patterns are shown, including a downstream shift in activity through time. In the 20th century, both rivers experienced deep main-channel incision and floodplain alluviation of natural levees and abandoned channels. Buried trees rooted in pre- mining soils indicate the Feather has not returned to pre-mining base levels below the Yuba confluence. Early engineering works controlled channel responses and recovery. For example, the Feather River avulsed into a channel dredged through Shanghai Bend (c.1907) so it now crosses resistant Quaternary alluvium over a 3-m knickpoint bench that could soon be breached. Moreover, levees and channelization near the Yuba-Feather confluence at Marysville (c.1905) narrowed and deepened flows, encouraging the bed incision noted by Gilbert. Effects of legacy sediment on channel processes are well known. Here, channel recovery was also constrained by channel morphologies engineered with boulder wing dams and revetment in the Yuba and channelization and levees in the Feather. The resulting bed incision reduces lateral connectivity between channels and floodplains and increases sediment conveyance. Historical and anthropogenic perspectives are essential to explaining channel dynamics at these scales. Unless models of channel and floodplain evolution recognize historical changes and engineering works, they may miss crucial components of geomorphic change and potential impacts downstream. In such systems, the historical dimension is essential to river management, water

  9. The design and construction of the Shikwamkwa replacement dam

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, C.R.; Rigbey, S.J.; Rigby, G. [Hatch Energy, Niagara Falls, ON (Canada); Clark, C. [Brookfield Power, Gatineau, PQ (Canada)

    2007-07-01

    The original Shikwamkwa dam was constructed in 1958 near Wawa, Ontario. It was a zoned earth-fill structure founded on a deep, central impervious core and complex overburden deposit. The primary defence against foundation seepage was a relatively short and thin impervious blanket constructed directly on the course grained river alluvium that was susceptible to piping. Serious incidents occurred shortly after impoundment in 1958, including the development of deep sinkholes in the reservoir, migration of fine particles through the foundation, and boiling at the downstream toe of the dam which continued to cause problems for decades. As the foundation was clearly deteriorated as evidenced by numerous sinkholes in the head pond and boils downstream, as well as concentrated seepage that had formed distinct pathways through the dam, a dam safety management plan was implemented in 1994 involving a phased program of remedial works designed to extend the life of this dam and to provide information on the nature of the problem and the foundation itself. This paper discussed the phased and managed approach for maintaining the safety of the Shikwamkwa dam. The paper provided detailed information on the remedial works program as well as the requirement for a new dam. Analysis of the changing hydrogeological conditions were done using a three-dimensional seepage model. Design and construction of the replacement dam, the use of enriched till in the embankment dam, the design of a plastic concrete cutoff wall, and the sealing between the cutoff wall and irregular bedrock surface using grouting were also outlined. Last, quality control for the cutoff wall and constructing dewatering were discussed. It was concluded that the project was successfully implemented following a fast track design and construction approach. 2 refs., 10 figs.

  10. A strategy to seal exploratory boreholes in unsaturated tuff

    International Nuclear Information System (INIS)

    This report presents a strategy for sealing exploratory boreholes associated with the Yucca Mountain Site Characterization Project. Over 500 existing and proposed boreholes have been considered in the development of this strategy, ranging from shallow (penetrating into alluvium only) to deep (penetrating into the groundwater table). Among the comprehensive list of recommendations are the following: Those boreholes within the potential repository boundary and penetrating through the potential repository horizon are the most significant boreholes from a performance standpoint and should be sealed. Shallow boreholes are comparatively insignificant and require only nominal sealing. The primary areas in which to place seals are away from high-temperature zones at a distance from the potential repository horizon in the Paintbrush nonwelded tuff and the upper portion of the Topopah Spring Member and in the tuffaceous beds of the Calico Hills Unit. Seals should be placed prior to waste emplacement. Performance goals for borehole seals both above and below the potential repository are proposed. Detailed construction information on the boreholes that could be used for future design specifications is provided along with a description of the environmental setting, i.e., the geology, hydrology, and the in situ and thermal stress states. A borehole classification scheme based on the condition of the borehole wall in different tuffaceous units is also proposed. In addition, calculations are presented to assess the significance of the boreholes acting as preferential pathways for the release of radionuclides. Design calculations are presented to answer the concerns of when, where, and how to seal. As part of the strategy development, available technologies to seal exploratory boreholes (including casing removal, borehole wall reconditioning, and seal emplacement) are reviewed

  11. Atmospheric transport of mineral dust from the Indo-Gangetic Plain: Temporal variability, acid processing, and iron solubility

    Science.gov (United States)

    Srinivas, Bikkina; Sarin, M. M.; Rengarajan, R.

    2014-08-01

    transport of chemical constituents from the Indo-Gangetic Plain (IGP) to the Bay of Bengal is a conspicuous seasonal feature that occurs during the late NE-monsoon (December-March). With this perspective, aerosol composition and abundance of mineral dust have been studied during November 2009 to March 2010 from a sampling site (Kharagpur: 22.3°N, 87.3°E) in the IGP, representing the atmospheric outflow to the Bay of Bengal. The chemical composition of PM2.5 suggests the dominance of nss-SO42- (6.9-24.3 µg m-3); whereas the abundance of mineral dust varied from 3 to 18 µg m-3. The concentration of aerosol iron (FeTot) and its fractional solubility (Fews % = Fews/FeTot *100, where Fews is the water-soluble fraction of FeTot) varied from 60 to 1144 ng m-3 and from 6.7 to 26.5%, respectively. A striking similarity in the temporal variability of total inorganic acidity (TIA = NO3- + nss-SO42-) and Fews (%) provides evidence for acid processing of mineral dust (alluvium) during atmospheric transport from the IGP. The contribution of TIA to water-soluble inorganic species [(nss-SO42- + NO3-)/ΣWSIS], mass ratios of Ca/Al and Fe/Al, and abundance of dust (%) and Fews (%) in the IGP-outflow are similar to the aerosol composition over the Bay of Bengal. With the rapid increase in anthropogenic activities over south and south-east Asia, the enhanced fractional solubility of aerosol iron (attributed to acid processing of mineral dust) has implications to further increase in the air-sea deposition of Fe to the Ocean surface.

  12. Geology of the Golden Gate Highlands National Park

    Directory of Open Access Journals (Sweden)

    G.H. Groenewald

    1986-12-01

    Full Text Available The Golden Gate Highlands National Park is underlain by stratigraphic units belonging to the upper part of the Karoo Sequence. These units include part of the Beaufort Group and the Molteno, Elliot, Clarens and Drakensberg Formations. Dolerite dykes and sills are intruded into the succession while recent alluvium and scree cover the valley floors and mountain slopes. The Beaufort Group is represented by red mudstone and light brown fine-grained feldspathic sandstone of the Tarkastad Subgroup. The Molteno Formation consists of medium- to coarse-grained trough cross-bedded sandstone, while the Elliot Formation comprises a thick succession of red mudstone, siltstone and interlayered fine- to medium-grained, light yellow-brown sandstone. The most characteristic feature of the park is the yellowish sandstone cliffs of the Clarens Formation. Cave formation is caused by exudation, differential weathering due to different degrees of carbonate cementation and undercutting of the sandstone. The highest peaks are capped by numerous layers of amygdaloidal and massive varieties of basaltic lava of the Drakensberg Formation. A possible volcanic pipe occurs in the eastern part of the park. The Elliot and Clarens Formations are rich in vertebrate fossil remains, especially Massospondylus sp. Remains of Notochampsa sp., Pachygenelus monus, Clarencea gracilis, Lanasaurus scalpridens and a cluster of unidentified dinosaur eggs have also been found. The formations underlying the Golden Gate Highlands National Park were formed during the Late Triassic Epoch and the Jurassic Period (roughly 150 to 230 million years ago. The strata in the park show very little structural deformation and the only obvious structures are faults which are intruded by dolerite.

  13. Geohydrology and saline ground-water discharge to the South Fork Ninnescah River in Pratt and Kingman Counties, south-central Kansas

    Science.gov (United States)

    Gillespie, Joe B.; Hargadine, G.D.

    1994-01-01

    Saline ground water discharges to the South Fork Ninnescah River in Pratt and Kingman Counties from the adjacent alluvial aquifer. Electromagnetic terrain surveys in this area indicated that the saline ground water is entering the river in intermittent reaches along the channel. The chloride concentration in the river near Murdock exceeds 250 milligrams per liter 75 percent of the time. During base flow in November 1988, stream discharge increased 67 cubic feet per second, and the chloride concentration increased 360 milligrams per liter from Pratt to the Pratt-Kingman County line. The chloride load to the river along this reach was 82 tons per day. The source of saline water probably is dissolution of salt in the Permian rocks, about 600 feet below land surface. Subsequent subsidence and collapse of Permian rocks into salt-dissolution cavities probably has caused fracturing in overlying Permian rocks. Brine moves upward through the Permian rocks and discharges into the alluvial aquifer. The brine discharge to the alluvium is about 0.7 cubic foot per second. In the area of major saline-water discharge to the river, the fluid-potential levels in the Permian rocks are higher than fluid-potential levels in the alluvial aquifer. Several methods for reducing the saline ground-water discharge to the South Fork Ninnescah River have been considered. The most effective of these methods appears to be interception of brine flow in the Permian rocks by pumping of relief wells. Brine could be disposed by injection into deeper formations, by storage in evaporation reservoirs, or by desalinization.

  14. A comparison of post-wildfire geomorphic response over annual and millennial time scales

    Science.gov (United States)

    Schaffrath, K. R.; Belmont, P.

    2014-12-01

    Wildfires have profound, highly variable impacts on erosion, sediment transport, and stream channel morphology. Climate change and fuel management actions have altered the current fire regime relative to the historic fire regime. Many researchers have quantified post-fire geomorphic response immediately following events and also over millennial timescales using geochronologic techniques and field study. While these studies have informed our understanding of the post-fire geomorphic response during the dry and wet periods of the Holocene, there are still some fundamental questions about long-term landscape erosion that we have yet to answer, particularly in fire-dominated landscapes. The Hayman fire burned 55,700 hectares in Pikes Peak National Forest, Colorado in 2002. Hillslope- and small watershed-scale sediment yield data were previously collected for 5 to 7 years in areas burned by high severity immediately after the fire. Plot data from 33 hillslope-scale plots indicate an average of 0.8 mm per year of erosion. Wildfires are common to this area and there is observable evidence of extreme geomorphic response following historic fires, similar to what has been monitored after the Hayman fire. In this study, we collected samples of channel alluvium deposited since the Hayman fire and sediment from alluvial fans thought to have been deposited in association with wildfires that may have occurred pre-European settlement. Samples were used to measure in-situ 10Be to estimate millennial-scale, catchment-averaged denudation rates that were compared to the erosion rates measured from the hillslope and watershed-scale plots to determine the proportion of erosion that is generated post-wildfire relative to undisturbed periods. Material from older alluvial fans was collected to try to evaluate whether denudation rates have changed and the ages of the older alluvial fans were determined using radiocarbon or optically-stimulated luminescence.

  15. Radionuclide Transport in Tuff and Carbonate Fractures from Yucca Flat, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Zavarin, M; Johnson, M R; Roberts, S K; Pletcher, R; Rose, T P; Kersting, A B; Eaton, G; Hu, Q; Ramon, E; Walensky, J; Zhao, P

    2006-02-01

    In the Yucca Flat basin of the Nevada Test Site (NTS), 747 shaft and tunnel nuclear detonations were conducted primarily within the tuff confining unit (TCU) or the overlying alluvium. The TCU in the Yucca Flat basin is hypothesized to reduce radionuclide migration to the regional carbonate aquifer (lower carbonate aquifer) due to its wide-spread aerial extent and chemical reactivity. However, shortcuts through the TCU by way of fractures may provide a migration path for radionuclides to the lower carbonate aquifer (LCA). It is, therefore, imperative to understand how radionuclides migrate or are retarded in TCU fractures. Furthermore, understanding the migration behavior of radionuclides once they reach the fractured LCA is important for predicting contaminant transport within the regional aquifer. The work presented in this report includes: (1) information on the radionuclide reactive transport through Yucca Flat TCU fractures (likely to be the primary conduit to the LCA), (2) information on the reactive transport of radionuclides through LCA fractures and (3) data needed to calibrate the fracture flow conceptualization of predictive models. The predictive models are used to define the extent of contamination for the Underground Test Area (UGTA) project. Because of the complex nature of reactive transport in fractures, a stepwise approach to identifying mechanisms controlling radionuclide transport was used. In the first set of TCU experiments, radionuclide transport through simple synthetic parallel-plate fractured tuff cores was examined. In the second, naturally fractured TCU cores were used. For the fractured LCA experiments, both parallel-plate and rough-walled fracture transport experiments were conducted to evaluate how fracture topography affects radionuclide transport. Tuff cores were prepared from archived UE-7az and UE-7ba core obtained from the USGS core library, Mercury, Nevada. Carbonate cores were prepared from archived ER-6-1 core, also obtained

  16. Soil survey of Solid Waste Storage Area 6

    International Nuclear Information System (INIS)

    An intensive soil survey was made of Solid Waste Storage Area (SWSA) 6 (Oak Ridge National Laboratory) at a scale of 1:1200. The amount of chemical weathering, the thickness of upland soils, and the depth to unoxidized rock are dependent on slope gradient, water-flow pathways, degree of rock fracturing, and the extent of soil and rock erosion by late Pleistocene and Holocene geomorphic processes. Foot-slope landforms have generally concave slope shapes where sediment accumulates. Colluvium stratigraphy exhibits at least one lithologic discontinuity, but there may be two discontinuities preserved in some thicker colluvia. One or more paleosols, either complete or partially truncated, are preserved in these concave landforms. Alluvial soils were not examined in detail but were separated from colluvial soils because of their wetness. A small area of ancient alluvium was located on a stable upland summit that formed the highest elevation in SWSA-6. On the nearly level summit, a thin loess cap was preserved on the older alluvial soil. Upland and colluvial soils are all highly leached and strongly acid even though they are formed from a calcareous parent rock. The highly fractured rock, being relatively permeable, has been leached free of carbonates in the upper levels so that there is a wide pH gradient from the surface downward. Most of the soils were classified as Ultisols, with minimal areas of Alfisols, Inceptisols, and Entisols. Based on the soil survey, representative landforms and soils will be selected to study physical, chemical, and mineralogical properties of the soil and weathered rock. Those properties will be used to predict both the amount and duration of leachate filtration and purification in downward migration to the water table or lateral migration through colluvial and alluvial soils to ground-water seeps

  17. Primary fractures within a tuff cone, North Menan Butte, Idaho, U.S.A.

    Science.gov (United States)

    Russell, W. J.; Brisbin, W. C.

    1990-01-01

    North Menan Butte is a tuff cone near Idaho Falls, Idaho. It is a result of the eruption of basaltic magma through shallow water-saturated river alluvium of the Snake River. The cone is characterized by primary fractures that can be classified into four groups on the basis of their physical properties and their orientations relative to the symmetry elements of the cone. Type I fractures are short, closely spaced and usually confined to individual beds. They strike approximately at right angles to cone radii and always dip toward the rim of the tuff cone. Bed segments separated by these fractures have undergone rotation, resulting in normal displacements. Type II fractures have similar attitudes but are more continuous, less frequent, and show no shear displacement. Type III fractures also strike at right angles to cone radii, but they dip away from the cone rim. They cut across several beds and reveal inconsistent senses of shear displacement. Type IV fractures are radial, steeply dipping and tend to be the most continuous of all fracture types. Type I fractures were the earliest to develop; age relationships otherwise are uncertain. Examples of all four types of fractures are exposed on the inner and outer eroded slopes of the cone. Evidence from the cone indicates that the fractures developed in an unconsolidated aggregate of tuff with low cohesion; therefore, analysis of fracture genesis should be constrained by principles of soil mechanics. Type I fractures originated as tension fractures related to early downslope mass movement. Later movement on Type I fractures accompanied the development of Type III shear fractures and possible bedding plane displacements, all caused by overloading the crest of the cone by late-stage eruptive products. The origin of Type II fractures is unknown; shrinkage due to desiccation or large-scale creep are possible explanations. The radial Type IV fractures may be a consequence of desiccation shrinkage or possibly of subcone

  18. Analysis of single ring infiltrometer test by direct numerical modeling

    Science.gov (United States)

    Réfloch, Aurore; Oxarango, Laurent; Rossier, Yvan; Gaudet, Jean Paul

    2016-04-01

    The well field of the Lyon metropolitan area provides drinking water to approximately 1,300,000 inhabitants. It is equipped with 12 infiltration basins. These basins have two main goals: sustaining the water table in times of peak demand for water, and preventing a possible contamination from the Rhône river by inverting groundwater flow direction. The water infiltration under the basins is thus crucial for the overall hydrogeologic behavior of the site. In order to characterize this phenomenon, a set of infiltrometer tests were performed to estimate the soil hydraulic properties. The soil is a coarse alluvial deposits. In order to deal with its sparse granulometric curve, a large single ring infiltrometer (1 meter in diameter) was used. A constant hydraulic head (=0.07 m) was imposed during the test. Two kinds of data are recorded: the amount of water infiltrated over time and the extension of the moisture stain around the ring. The main hydraulic properties are estimated using Richard's equation in a 2D axi-symmetric configuration. Simulations are performed using a finite element commercial software package (Comsol Multiphysics 5.1). According to simplified numerical models, an average homogeneous saturated permeability of the alluvial deposits is estimated at 5.0 10-6 m.s-1. However, such a simple model is not able to represent accurately the moisture stain at the soil surface. More complex models introduce anisotropy of permeability in the alluvium layer, with mono or bi-layer domain. In these cases, experimental and modeling results are consistent, both for the amount of water infiltrated over time and the extension of the moisture stain around the ring. The hydraulic anisotropy in the soil could be due to the stratified nature of alluvial deposits and to soil compaction during the construction of infiltration basins. Keywords: Single ring infiltrometer test, artificial aquifer recharge, numerical modeling.

  19. Channel evolution on the dammed Elwha River, Washington, USA

    Science.gov (United States)

    Draut, A.E.; Logan, J.B.; Mastin, M.C.

    2011-01-01

    Like many rivers in the western U.S., the Elwha River, Washington, has changed substantially over the past century in response to natural and human forcing. The lower river is affected by two upstream dams that are slated for removal as part of a major river restoration effort. In preparation for studying the effects of dam removal, we present a comprehensive field and aerial photographic analysis of dam influence on an anabranching, gravel-bed river. Over the past century with the dams in place, loss of the upstream sediment supply has caused spatial variations in the sedimentary and geomorphic character of the lower Elwha River channel. Bed sediment is armored and better sorted than on the naturally evolving bed upstream of the dams. On time scales of flood seasons, the channel immediately below the lower dam is fairly stable, but progresses toward greater mobility downstream such that the lowermost portion of the river responded to a recent 40-year flood with bank erosion and bed-elevation changes on a scale approaching that of the natural channel above the dams. In general, channel mobility in the lowest 4 km of the Elwha River has not decreased substantially with time. Enough fine sediment remains in the floodplain that – given sufficient flood forcing – the channel position, sinuosity, and braiding index change substantially. The processes by which this river accesses new fine sediment below the dams (rapid migration into noncohesive banks and avulsion of new channels) allow it to compensate for loss of upstream sediment supply more readily than would a dammed river with cohesive banks or a more limited supply of alluvium. The planned dam removal will provide a valuable opportunity to evaluate channel response to the future restoration of natural upstream sediment supply.

  20. The implementing of some plant species in erosion control on slopes

    Directory of Open Access Journals (Sweden)

    Matić Vjačeslava

    2010-01-01

    Full Text Available With the need to conserve and improve the environment, it is recommended to employ plant materials in the erosion control of torrents and slopes alongside roads. Considering the well-known properties of some willow species regarding their power of vegetative reproduction, survival in poor soils and often flooded alluvium, we researched into the potentials of the following species: Salix triandra L., Salix purpurea L. and Salix incana Schrk. in the catchment of the warehouse 'Gvozdac', Experimental Estate Goč, Serbia. The research started in 2004 and has continued till the present day. The above-mentioned willow species showed significant efficiency in the bank protection of torrential watercourses and on the moist slopes of embankments and cuts of roads. Some of them can even stand a certain degree of aridity, while other species, on poor, eroded soil exposed to long and extreme drought, could not survive and did not show the expected effect, which is also the consequence of the absence of maintenance and adequate attention to such erosion-control works. In spite of the above, one of the willow species survived even in the most severe conditions, checking the erosion of the road cut slope and the road construction itself, and prevented the impacts of aggressive atmospheric waters, thus halting the erosion ridges and the removal of the asphalt road surface. The above facts prove that, with adequate measures of maintenance, plant materials can be very successfully applied for both longitudinal structures and to check dams in torrent control, as well as in erosion control on the slopes in catchments, both in civil engineering works and in forest exploitation. The research requires closer attention, extending the interests to some grass and shrub species, with the aim of ecological erosion control and reclamation of endangered watercourses, slopes and, in general, environmental protection and nature conservation. .

  1. Late Cenozoic surficial deposits and valley evolution of unglaciated northern New Jersey

    Science.gov (United States)

    Stanford, S.D.

    1993-01-01

    Multiple alluvial, colluvial, and eolian deposits in unglaciated northern New Jersey, and the eroded bedrock surfaces on which they rest, provide evidence of both long-term valley evolution driven by sustained eustatic baselevel lowering and short-term filling and excavation of valleys during glacial and interglacial climate cycles. The long-term changes occur over durations of 106 years, the short-term features evolve over durations of 104 to 105 years. Direct glacial effects, including blockage of valleys by glacial ice and sediment, and valley gradient reversals induced by crustal depression, are relatively sudden changes that account for several major Pleistocene drainage shifts. After deposition of the Beacon Hill fluvial gravel in the Late Miocene, lowering of sea level, perhaps in response to growth of the Antarctic ice sheet, led to almost complete dissection of the gravel. A suite of alluvial, colluvial, and eolian sediments was deposited in the dissected landscape. The fluvial Bridgeton Formation was deposited in the Raritan lowland, in the Amboy-Trenton lowland, and in the Delaware valley. Following southeastward diversion of the main Bridgeton river, perhaps during Late Pliocene or Early Pleistocene glaciation, northeastward drainage was established on the inactive Bridgeton fluvial plain. About 30 to 45 m of entrenchment followed, forming narrow, incised valleys within which Late Pleistocene deposits rest. This entrenchment may have occurred in response to lowered sea level caused by growth of ice sheets in the northern hemisphere. Under periglacial conditions in the Middle and Late Pleistocene, valleys were partially filled with alluvium and colluvium. During interglacials slopes were stabilized by vegetation and the alluvial and colluvial valley-fill was excavated by gullying, bank erosion, and spring sapping. During Illinoian and late Wisconsinan glaciation, the lower Raritan River was diverted when glacial deposits blocked its valley, and the

  2. Drilling and coring methods that minimize the disturbance of cuttings, core, and rock formation in the unsaturated zone, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    A drilling-and-casing method (Odex 115 system) utilizing air as a drilling fluid was used successfully to drill through various rock types within the unsaturated zone at Yucca Mountain, Nevada. This paper describes this method and the equipment used to rapidly penetrate bouldery alluvial-colluvial deposits, poorly consolidated bedded and nonwelded tuff, and fractured, densely welded tuff to depths of about 130 meters. A comparison of water-content and water-potential data from drill cuttings with similar measurements on rock cores indicates that drill cuttings were only slightly disturbed for several of the rock types penetrated. Coring, sampling, and handling methods were devised to obtain minimally disturbed drive core from bouldery alluvial-colluvial deposits. Bulk-density values obtained from bulk samples dug from nearby trenches were compared to bulk-density values obtained from drive core to determine the effects of drive coring on the porosity of the core. Rotary coring methods utilizing a triple-tube core barrel and air as the drilling fluid were used to obtain core from welded and nonwelded tuff. Results indicate that the disturbance of the water content of the core was minimal. Water-content distributions in alluvium-colluvium were determined before drilling occurred by drive-core methods. After drilling, water-content distributions were determined by nuclear-logging methods. A comparison of the water-content distributions made before and after drilling indicates that Odex 115 drilling minimally disturbs the water content of the formation rock. 10 refs., 12 figs., 4 tabs

  3. Sone megafan: A non-Himalayan megafan of craton origin on the southern margin of the middle Ganga Basin, India

    Science.gov (United States)

    Sahu, Sudarsan; Saha, Dipankar; Dayal, Shankar

    2015-12-01

    Researchers in the last few decades have focused on the fluvial megafans at the base of Himalayan foothills in the Ganga Basin. No major effort has so far been made to delineate any such large depositional environment at the base of the northern Indian peninsular craton at the distal parts of the basin. In this work, for the first time, we document a megafan, unusually created by the cratonic Sone River in the marginal plains south of the Ganga. The geomorphology of the megafan surface, distribution of palaeochannels, sedimentology, and areal extent of the megafan are described. The study also reconstructs the tectonic and palaeoclimatic conditions, which might have helped in sediment supply from the cratonic catchment areas of the Sone. We suggest tectonic control over the Sone River channel dynamics and development of the megafan. The oval- and fan-shaped, craton-derived sediment body covers an area of around 12,000 km2 in the marginal plains and about 9000 km2 in the central alluvium north of the Ganga River. The megafan is around 190 km long and ~ 240 km wide. The mean slope of the megafan surface is ~ 0.03°. An onlap of Himalayan sediments has occurred over the megafan at its toe parts caused by southward encroachment of the Ganga during the Holocene. The megafan sediments comprise brownish yellow fine to coarse sand and gravels with an admixture of carbonaceous nodules (kankars). The thickness of the megafan sediment, which directly overlies the Precambrian basement, varies from only a few meters in the south near the peninsular craton to ~ 1000 m at the north in the central alluvial plain. The granular zones form prolific aquifer systems in an otherwise poor hydrogeological setting of the marginal plains.

  4. The paradigm of paraglacial megafans of the San Juan river basin, Central Andes, Argentina

    Science.gov (United States)

    Suvires, Graciela M.

    2014-11-01

    The spatial distribution and several morphometric characteristics of the Quaternary alluvial fans of the San Juan River, in the province of San Juan, at the Central and Western part of Argentina, have been studied to classify them as paraglacial megafans, as well to ratify its depositional environmental conditions. The high sedimentary load exported by San Juan river from the Central Andes to the foreland depressions is estimated about 3,682,200 hm3. The large alluvial fans of Ullum-Zonda and Tulum valleys were deposited into deep tectonic depressions, during the Upper Pleistocene deglaciation stages. The outcome of collecting remotely sensed data, map and DEM data, geophysical data and much fieldwork gave access to morphometric, morphographic and morphogenetic data of these alluvial fans. The main drainage network was mapped on processed images using QGis (vers.2.0.1). Several fan morphometric parameters were measured, such as the size, the shape, the thickness, the surface areas and the sedimentary volume of exported load. The analyzed fans were accumulated in deep tectonic depressions, where the alluvium fill reaches 700 to 1200 m thick. Such fans do not reach the large size that other world megafans have, and this is due to tectonic obstacles, although the sedimentary fill average volume surpasses 514,000 hm3. The author proposes to consider Ullum-Zonda and Tulum alluvial fans as paraglacial megafans. According to the stratigraphic relationships of the tropical South American Rivers, the author considers that the San Juan paraglacial megafans would have occurred in the period before 24 ka BP , possibly corresponding to Middle Pleniglacial (ca 65-24ka BP). They record colder and more humid conditions compared with the present arid and dry conditions.

  5. δ13C values of soil organic matter in semiarid grassland with mesquite (Prosopis) encroachment in southeastern Arizona

    Science.gov (United States)

    Biggs, Thomas H.; Quade, Jay; Webb, Robert H.

    2002-01-01

    Over the past century, C3 woody plants and trees have increased in abundance in many semiarid ecosystems, displacing native C4 grasses. Livestock grazing, climatic fluctuations, and fire suppression are several reasons proposed for this shift. Soil carbon isotopic signatures are an ideal technique to evaluate carbon turnover rates in such ecosystems. On the gunnery ranges of Fort Huachuca in southeastern Arizona, study sites were established on homogeneous granitic alluvium to investigate the effects of fire frequency on δ13C values in surface soil organic matter (SOM). These ranges have had no livestock grazing for 50 years and a well-documented history of fires. Prosopis velutina Woot. (mesquite) trees have altered SOM δ13C pools by the concentration of plant nutrients and the addition of isotopically light litter. These soil carbon changes do not extend beyond canopy margins. Elevated total organic carbon (TOC), plant nutrient (N and P) concentrations, and depleted SOM δ13C values are associated with C3Prosopis on an unburned plot, which enables recognition of former Prosopis-occupied sites on plots with recent fire histories. Elevated nutrient concentrations associated with former Prosopis are retained in SOM for many decades. Surface SOM δ13C values indicate the estimated minimum turnover time of C4-derived carbon beneath large mature Prosopis is about 100–300 years. In contrast, complete turnover of original C3 carbon to C4 carbon under grasslands is estimated to take a minimum of 150–500 years. Our study confirms that C4 grass cover has declined over the past 100 years, although isolated C3 trees or shrubs were not uncommon on the historic C4-dominated grasslands. We find evidence in surface soil layers for a modern C3 plant expansion reflected in the substantial shift of SOM δ13C values from C4 grasses to C3 shrublands.

  6. Correlation of 1- to 10-Hz earthquake resonances with surface measurements of S-wave reflections and refractions in the upper 50 m

    Science.gov (United States)

    Williams, R.A.; Stephenson, W.J.; Frankel, A.D.; Cranswick, E.; Meremonte, M.E.; Odum, J.K.

    2000-01-01

    Resonances observed in earthquake seismograms recorded in Seattle, Washington, the central United States and Sherman Oaks, California, are correlated with each site's respective near-surface seismic velocity profile and reflectivity determined from shallow seismic-reflection/refraction surveys. In all of these cases the resonance accounts for the highest amplitude shaking at the site above 1 Hz. These results show that imaging near-surface reflections from the ground surface can locate impedance structures that are important contributors to earthquake ground shaking. A high-amplitude S-wave reflection, recorded 250-m northeast and 300-m east of the Seattle Kingdome earthquake-recording station, with a two-way travel time of about 0.23 to 0.27 sec (about 18- to 22-m depth) marks the boundary between overlying alluvium (VS Hz resonance that is observed in the earthquake data for the site near the Kingdome. In the central United States, S-wave reflections from a high-impedance boundary (an S-wave velocity increase from about 200 m/sec to 2000 m/sec) at about 40-m depth corresponds to a strong fundamental resonance at about 1.5 Hz. In Sherman Oaks, strong resonances at about 1.0 and 4 Hz are consistently observed on earthquake seismograms. A strong S-wave reflector at about 40-m depth may cause the 1.0 Hz resonance. The 4.0-Hz resonance is possibly explained by constructive interference between the first overtone of the 1.0-Hz resonance and a 3.25- to 3.9-Hz resonance calculated from an areally consistent impedance boundary at about 10-m depth as determined by S-wave refraction data.

  7. The information content of high-frequency seismograms and the near-surface geologic structure of "hard rock" recording sites

    Science.gov (United States)

    Cranswick, E.

    1988-01-01

    Due to hardware developments in the last decade, the high-frequency end of the frequency band of seismic waves analyzed for source mechanisms has been extended into the audio-frequency range (>20 Hz). In principle, the short wavelengths corresponding to these frequencies can provide information about the details of seismic sources, but in fact, much of the "signal" is the site response of the nearsurface. Several examples of waveform data recorded at "hard rock" sites, which are generally assumed to have a "flat" transfer function, are presented to demonstrate the severe signal distortions, including fmax, produced by near-surface structures. Analysis of the geology of a number of sites indicates that the overall attenuation of high-frequency (>1 Hz) seismic waves is controlled by the whole-path-Q between source and receiver but the presence of distinct fmax site resonance peaks is controlled by the nature of the surface layer and the underlying near-surface structure. Models of vertical decoupling of the surface and nearsurface and horizontal decoupling of adjacent sites on hard rock outcrops are proposed and their behaviour is compared to the observations of hard rock site response. The upper bound to the frequency band of the seismic waves that contain significant source information which can be deconvolved from a site response or an array response is discussed in terms of fmax and the correlation of waveform distortion with the outcrop-scale geologic structure of hard rock sites. It is concluded that although the velocity structures of hard rock sites, unlike those of alluvium sites, allow some audio-frequency seismic energy to propagate to the surface, the resulting signals are a highly distorted, limited subset of the source spectra. ?? 1988 Birkha??user Verlag.

  8. Ground-water flow and quality, and geochemical processes, in Indian Wells Valley, Kern, Inyo, and San Bernardino counties, California, 1987-88

    Science.gov (United States)

    Berenbrock, Charles; Schroeder, R.A.

    1994-01-01

    An existing water-quality data base for the 300- square-mile Indian Wells Valley was updated by means of chemical and isotopic analysis of ground water. The wide range in measured concentrations of major ions and of minor constituents such as fluoride, borate, nitrate, manganese, and iron is attributed to geochemical reactions within lacustrine deposits of the valley floor. These reactions include sulfate reduction accompanied by generation of alkalinity, precipitation of carbonates, exchange of aqueous alkaline-earth ions for sodium on clays, and dissolution of evaporite minerals. Differences in timing and location of recharge, which originates primarily in the Sierra Nevada to the west, and evapotranspiration from a shallow water table on the valley floor result in a wide range in ratios of stable hydrogen and oxygen isotopes. As ground water moves from alluvium into lustrine deposits of the ancestral China Lake, dissolved-solids concen- trations increase from about 200 to more than 1,000 milligrams per liter; further large increases to several thousand milligrams per liter occur beneath the China Lake playa. Historical data show an increase during the past 20 years in dissolved- solids concentration in several wells in the principal pumping areas at Ridgecrest and between Ridgecrest and Inyokern. The increase apparently is caused by induced flow of saline ground water from nearby China, Mirror, and Satellite Lakes. A simplified advective-transport model calculates ground-water travel times between parts of the valley of at least several thousand years, indi- cating the presence of old ground water. A local ground-water line and an evaporation line estimated using isotopic data from the China Lake area inter- sect at a delta-deuterium value of about -125 permil. This indicates that late Pleistocene recharge was 15 to 35 permil more negative than current recharge.

  9. METALLOGENY OF SOUTH TISIA - MOSLAVAČKA MT., PSUNJ, PAPUK AND KRNDIJA

    Directory of Open Access Journals (Sweden)

    Ivan Jurković

    2013-12-01

    Full Text Available Core of the Moslavačka Mt. is built of S-type granite and granodiorite, wrapped up in migmatites. Outer zone is represented with metamorphites of amphibolite facies. The Moslavačka Mt. is a product of regional metamorphism on Lower Paleozoic pelito-psammitic protholite. Numerous quarries exploited granite, amphibolite, gabbro, orthogneiss. Stronger concentrations of sillimanite, andalusite, cordierite, garnet, and tourmaline were observed in different types of rocks. The pegmatite phase generated veins and irregular boddies of metasomatic-injected pegmatites with garnet and tourmaline. Hydrothermal quartz veinlets with sulphides have only mineralogical significance. Migmatites and S-granites form central parts of the Slavonian Mts. Dating gave age of 314-333 Ma (Namurian-Westphalian. Metaclastites of lower metamorphic sequences contain palynomorphs from Silurian to the Lower Carboniferous. Graphitite deposits generated by regional metamorphism were exploited in the mines Brusnik, Sivornica and Brezovo Polje in the Psunj Mt. and in the mine Kapitol in the Papuk Mt. Numerous metasomatic injected pegmatites were exploited on the locations Veliki and Mali Debeljak, Točak, Bilo, Lom and quartz veins at Zavlaka and Motičina Gornja. Postcollisional I-granites gave a small volastonite skarn deposit in the Kiseljevački brook. Mineralogical occurrences of hematite, pyrite, asbestos and copper are genetically bounded with diabases. Talc-chlorite schists were exploited in the mine Koprivna (Psunj. Longlasting investigations of sedimentary uranium occurrences were negative. The best results were obtained in the Kaptol, Cipalovac and Ninkovac brooks. In the alluvium of numerous brooks more significant quantities of gold, monazite, rutile, zircon and scheelite were found (the paper is published in Croatian.

  10. The depositional setting of the Late Quaternary sedimentary fill in southern Bannu basin, Northwest Himalayan fold and thrust belt, Pakistan

    KAUST Repository

    Farid, Asam M.

    2014-07-10

    Geostatistical variogram and inversion techniques combined with modern visualization tools have made it possible to re-model one-dimensional electrical resistivity data into two-dimensional (2D) models of the near subsurface. The resultant models are capable of extending the original interpretation of the data to depict alluvium layers as individual lithological units within the 2D space. By tuning the variogram parameters used in this approach, it is then possible to visualize individual lithofacies and geomorphological features for these lithologic units. The study re-examines an electrical resistivity dataset collected as part of a groundwater study in an area of the Bannu basin in Pakistan. Additional lithological logs from boreholes throughout the area have been combined with the existing resistivity data for calibration. Tectonic activity during the Himalayan orogeny uplifted and generated significant faulting in the rocks resulting in the formation of a depression which subsequently has been filled with clay-silt and dirty sand facies typical of lacustrine and flood plain environments. Streams arising from adjacent mountains have reworked these facies which have been eroded and replaced by gravel-sand facies along channels. It is concluded that the sediments have been deposited as prograding fan shaped bodies, flood plain, and lacustrine deposits. Clay-silt facies mark the locations of paleo depressions or lake environments, which have changed position over time due to local tectonic activity and sedimentation. The Lakki plain alluvial system has thus formed as a result of local tectonic activity with fluvial erosion and deposition characterized by coarse sediments with high electrical resistivities near the mountain ranges and fine sediments with medium to low electrical resistivities towards the basin center. © 2014 Springer International Publishing Switzerland.

  11. A transgression-regression event during the deposition of the Upper Cambrian Honey Creek formation in the southern Oklahoma aulacogen

    Energy Technology Data Exchange (ETDEWEB)

    McElmoyl, C.; Donovan, R.N. (Texas Christian Univ., Ft. Worth, TX (United States). Geology Dept.)

    1993-02-01

    The transgression that inundated the Southern Oklahoma aulacogen during the upper Cambrian enveloped a landscape that consisted of hills of rhyolite up to 350 m in high. Initial deposits on this topography have been interpreted as alluvium. These, together with succeeding tidally-influenced marine siliciclastics form the Reagan Formation. The siliciclastics grains are made up of fragments of local origin (i.e., rhyolite), quartz (derived from a distal source) and authigenic glauconite. The upward passage from the Reagan to the Honeycreek Formation is defined by the addition to the siliciclastics of carbonate detritus in the form of tidally-influenced grainstones, mostly composed of pelmatozoan fragments. The passage from the Honeycreek to the overlying Fort Sill Formation of the Arbuckle Group is marked by the incoming of beds of lime mudstone and the gradual disappearance of grainstones and siliciclastics. Evidence of the existence of rhyolite topography (i.e., an archipelago) can be detected to within 50 m of the top of the Fort Sill. While the overall facies pattern undoubtedly records a widespread transgression, a newly-discovered slightly angular unconformity within the lower part of the Honeycreek is best interpreted as a record of a temporary regression. Three distinctive lithologies are involved in this relationship: the lowest beds are light grey cross-bedded pelmatozoan grainstones with minor amounts of quartz and rhyolite grains. Syntaxial cements at the base of this unit are homogenous under cathode luminescence, while cements near the top display up to 27 zones of reflectance, interpreted as a fluctuating marine-meteoric groundwater imprint. The overlying bed is a red-brown mud-supported limestone that contains abundant angular rhyolite pebbles and a rich trilobite fauna. Some of the pebbles are coated by pelmatozoans.

  12. The geological significance of the boundary between the Fort Sill and Signal Mountain Formations in the lower Arbuckle Group (Cambrian)

    Energy Technology Data Exchange (ETDEWEB)

    Hosey, R.; Donovan, R.N. (Texas Christian Univ., Ft Worth, TX (United States). Geology Dept.)

    1993-02-01

    During the upper Cambrian, a transgression inundated the Southern Oklahoma aulacogen enveloping a landscape that consisted of hills of Cambrian-aged rhyolite up to 350 m in height. Initial deposits on this topography--the Reagan Formation--consist of siliciclastics that were deposited as alluvium and succeeding tidally-influenced marine sandstones and shales. The siliciclastics grains are made up of local rhyolite, quartz and authigenic glauconite. The overlying Honeycreek Formation is defined by the addition of carbonated detritus in the form of tidally-influenced pelmatozoan grainstones. The passage from the Honeycreek to the overlying Fort Sill Formation of the Arbuckle Group is marked by the incoming of beds of lime mudstone and the gradual disappearance of grainstones and siliciclastics. The contact between the Fort Sill and the overlying thinly-bedded dark grey bioclastic limestones of the Signal Mountain Formation is one of the most distinctive horizons in the Arbuckle Group. The contact evidently marks a substantial change in depositional environment. In detail the contact is sharp and shows evidence of minor erosion, although no karsting has been detected. The authors suggest that the contact surface records a regression, perhaps associated with dolomitization and followed by some erosion. A regression is also indicated by the local occurrence of a laminated tidal flat unit with traces of evaporites that outcrops in the far west of the Slick Hills immediately below the formation contact. They suggest that the Signal Mountains as a transgressive unit, incorporating siliciclastics transported into the area during the regression. It has been suggested that the unconformity reflects localized tectonism associated with the evolution of the Southern Oklahoma aulacogen. On the other hand the surface may correlate with a craton--wide Sauxian' hiatus.

  13. The Meers Fault in Southern Oklahoma: Holocene Movements on a Fault with Pennsylvanian and Cambrian Linages

    Science.gov (United States)

    Keller, G. R.; Holland, A. A.; Luza, K.; Oldow, J. S.; Crain, K.

    2011-12-01

    The Meers fault and subparallel fault strands in southern Oklahoma is the southernmost element of the complex and massive (>10 km of throw) frontal fault zone that forms the boundary between the Anadarko basin, which is the deepest intra-continental basin in the United States, and the uplifted Cambrian igneous rocks of the Wichita Mountains. The Wichita uplift is evidence of extraordinary Pennsylvanian intra-plate deformation along the trend of the Southern Oklahoma aulacogen, which is a classic example of a failed and massively inverted rift. The Meers Fault is the best-documented Holocene fault scarp east of Colorado and probably represents reactivation of a Pennsylvanian oblique thrust that in turn is likely to be an inverted Cambrian normal fault. The magnitude of these structures is shown on images from 3-D industry seismic reflection data ~25 km northwest of the northwestern mapped extent of the Meers fault that indicate the Pennsylvanian structure, or a northern strand of it, has a reverse throw of ~6km at depth. The fault displays a conspicuous and continuous scarp that is at least 25 km long and is evident in air photos and 1:100,000 scale geologic mapping, but this feature is not well mapped in detail beyond the area of trenching studies conducted in the 1980's. In the Holocene, 3-5 m of vertical surface displacement has been documented and left-lateral strike slip displacement on the fault is 2-3 times greater than the vertical displacement. During this movement, Quaternary soils along the fault were folded and ruptured, and the scarp has dammed small gullies where fine-grained alluvium has collected and has been used in the dating efforts. The most recent movement occurred (1100-1300 y ago) with a variety of earlier events having been proposed. As such, this fault represents one of the highest potential seismic hazards in the central/eastern United States.

  14. Water availability and flood hazards in the John Day Fossil Beds National Monument, Oregon

    Science.gov (United States)

    Frank, Frank J.; Oster, E.A.

    1979-01-01

    The rock formations of the John Day Fossil Beds National Monument area are aquifers that can be expected to yield less than 10 gallons of water per minute to wells. The most permeable of the geologic units is the alluvium that occurs at low elevations along the John Day River and most of the smaller streams. Wells in the alluvial deposits can be expected to yield adequate water supplies for recreational areas; also, wells completed in the underlying bedrock at depths ranging from 50 to 200 feet could yield as much as 10 gallons per minute. Pumping tests on two unused wells indicated yields of 8 gallons per minute and 2 gallons per minute. Nine of the ten springs measured in and near the monument area in late August of 1978 were flowing 0.2 to 30 gallons per minute. Only the Cant Ranch spring and the Johnny Kirk Spring near the Sheep Rock unit had flows exceeding 6 gallons per minute. Chemical analyses of selected constituents of the ground water indicated generally low concentrations of dissolved minerals. Although cloudbursts in the Painted Hills unit could generate a flood wave on the valley floors, flood danger can be reduced by locating recreational sites on high ground. The campground in Indian Canyon of the Clarno unit is vulnerable to cloudburst flooding. About 80 percent of the proposed campground on the John Day River in the Sheep Rock unit is above the estimated level of 1-percent chance flood (100-year flood) of the river. The 1-percent chance flood would extend about 120 feet from the riverbank into the upstream end of the campground. (USGS).

  15. Changes in discharge and solute dynamics between hillslope and valley-bottom intermittent streams

    Directory of Open Access Journals (Sweden)

    S. Bernal

    2012-06-01

    Full Text Available To gain understanding on how alluvial zones modify water and nutrient export from semiarid catchments, we compared monthly discharge as well as stream chloride, carbon, and nitrogen dynamics between a hillslope catchment and a valley-bottom catchment with a well-developed alluvium. Stream water and solute fluxes from the hillslope and valley-bottom catchments showed contrasting patterns between hydrological transitions and wet periods, especially for bio-reactive solutes. During transition periods, stream water export decreased >40% between the hillslope and the valley bottom coinciding with the prevalence of stream-to-aquifer fluxes at the alluvial zone. In contrast, stream water export increased by 20–70% between the hillslope and valley-bottom catchments during wet periods. During transition periods, stream solute export decreased by 34–97% between the hillslope and valley-bottom catchments for chloride, nitrate, and dissolved organic carbon. In annual terms, stream nitrate export from the valley-bottom catchment (0.32 ± 0.12 kg N ha−1 yr−1 [average ± standard deviation] was 30–50% lower than from the hillslope catchment (0.56 ± 0.32 kg N ha−1 yr−1. The annual export of dissolved organic carbon was similar between the two catchments (1.8 ± 1 kg C ha−1 yr−1. Our results suggest that hydrological retention in the alluvial zone contributed to reduce stream water and solute export from the valley-bottom catchment during hydrological transition periods when hydrological connectivity between the hillslope and the valley bottom was low.

  16. River infiltration to a subtropical alluvial aquifer inferred using multiple environmental tracers

    Science.gov (United States)

    Lamontagne, S.; Taylor, A. R.; Batlle-Aguilar, J.; Suckow, A.; Cook, P. G.; Smith, S. D.; Morgenstern, U.; Stewart, M. K.

    2015-06-01

    Chloride (Cl-), stable isotope ratios of water (δ18O and δ2H), sulfur hexafluoride (SF6), tritium (3H), carbon-14 (14C), noble gases (4He, Ne, and Ar), and hydrometry were used to characterize groundwater-surface water interactions, in particular infiltration rates, for the Lower Namoi River (New South Wales, Australia). The study period (four sampling campaigns between November 2009 and November 2011) represented the end of a decade-long drought followed by several high-flow events. The hydrometry showed that the river was generally losing to the alluvium, except when storm-derived floodwaves in the river channel generated bank recharge—discharge cycles. Using 3H/14C-derived estimates of groundwater mean residence time along the transect, infiltration rates ranged from 0.6 to 5 m yr-1. However, when using the peak transition age (a more realistic estimate of travel time in highly dispersive environments), the range in infiltration rate was larger (4-270 m yr-1). Both river water (highest δ2H, δ18O, SF6, 3H, and 14C) and an older groundwater source (lowest δ2H, δ18O, SF6, 3H, 14C, and highest 4He) were found in the riparian zone. This old groundwater end-member may represent leakage from an underlying confined aquifer (Great Artesian Basin). Environmental tracers may be used to estimate infiltration rates in this riparian environment but the presence of multiple sources of water and a high dispersion induced by frequent variations in the water table complicates their interpretation.

  17. Information pertinent to the migration of radionuclides in ground water at the Nevada Test Site. Part 1. Review and analysis of existing information

    International Nuclear Information System (INIS)

    A history of NTS is given, the geologic and hydrologic setting is described, and the amount of radioactivity deposited within and near the main aquifers is estimated. The conclusions include: information currently available is insufficient to state categorically that radioactivity will never be carried off the Nevada Test Site by ground water movement; nonetheless, such a migration at levels above the maximum permissible concentration to existing wells and springs is considered unlikely; if offsite migration occurs, it will probably be from the southwestern margins of Pahute Mesa, where there is only a small chance of contaminating existing public water supplies; tritium is the most mobile radionuclide and may be the only long-lived isotope of concern. Highest priority is assigned to measurement of tritium and other radionuclides in large water samples taken from nuclear chimneys that water has re-entered after an explosion; expansion of the existing groundwater monitoring program at NTS to include wells with a higher probability of intersecting flow of contaminated water; measurement of groundwater flow velocities and other associated hydrologic parameters. High priority is assigned to production of an inventory of radionuclides deposited near NTS borders, especially beneath Pahute Mesa; determination of amounts of radioactivity deposited directly into the Lower Carbonate Aquifer; a sensitivity analysis of the many parameters that enter into transport calculations; a study of the many unplugged holes that penetrate the Tuff Aquitard; testing of the assumption that radionuclides deposited in the unsaturated zone are isolated from the saturated zone because of limited precipitation and downward movement of moisture; and determination of distribution coefficients for NTS alluvium, carbonate, and rhyolitic rocks, which are lacking or poorly represented in the literature. Twelve other recommendations of lesser priority are also given

  18. Re-writing the historical perceptions of semi-arid agriculture at the abandoned site of Engaruka, NE Tanzania

    Science.gov (United States)

    Lang, Carol; Stump, Daryl

    2016-04-01

    Archaeological excavations and surveys recognised as early as the 1960s that the extensive area of archaeological remains at Engaruka in northeast Tanzania were the remnants of former settlements overlooking c. 2000ha of agricultural fields and terraces served by a complex network of irrigation canals. Given that the area is now semi-arid and receives c. 400mm of rain per year, it was naturally assumed that this irrigation was necessary in order to undertake arable cultivation. However, recent and ongoing geoarchaeological research - including stratigraphy, micromorphology and geochemistry, complemented by archaeobotany and modelling of hydrology and sediment transport - demonstrates that the site was formerly much wetter. So much wetter, in fact, that farmers built fields containing soils with paddy-like characteristics, and constructed sediment traps that accumulated vast quantities of alluvium entrained within watercourses, resulting in deposits up to 60cm deep over an area of c. 900ha, and up to 2m deep (totally some 16,000 m3) within just one large terrace covering c. 0.6ha. This paper presents the stratigraphy, micromorphology and geochemistry of the site, discusses the importance of relating this wet phase (or phases) to broader palaeoclimatic signatures covering the period of the site's occupation between the 14th and mid- to late 18th century AD, and questions if and how data of this sort can inform assessments of systemic sustainability or resilience. Acknowledgements: European Research Council Starter Grand Scheme (FP/200702013/) ERC Grant Agreement No. ERC-StG-2012-337128-AAREA

  19. Laboratory studies of radionuclide distributions between selected groundwaters and geologic media

    International Nuclear Information System (INIS)

    Extensive studies of the behavior of plutonium and americium in pH 8 groundwaters were made, particularly with respect to container sorption, filtering, and centrifugation. Significant improvements in the method used for measuring sorption ratios for these elements were developed, and their sorption-desorption ratios on argillite and tuff were measured. Effects of particle size, temperature, sampling location, mineralogy, and time were investigated for these elements. The chemical composition of the water was found to be a major factor that governs sorption behavior for some elements. Studies of the sorption of strontium, cesium, barium, cerium, europium, uranium, and americium on Hainesville salt dome materials were made under aerobic and anoxic (< 0.2 ppm oxygen) conditions using two synthetic groundwaters: one represented the Wilcox aquifer in the Hainesville region and the second was a dilute brine. Studies of the sorption of strontium, cesium, barium, cerium, europium, and uranium(VI) on granite and argillite were made under anoxic (< 0.2 ppm oxygen) conditions and the results were compared to earlier measurements made under aerobic conditions. The sorption of uranium(VI) on argillite under atmospheric conditions was investigated. Measurements of migration rates in crushed granite, argillite, and tuff were made and compared with batch results. Infiltration experiments involving the forced injection of activity into intact and fractured cores were also performed. Microautoradiographic techniques were used to detect specific sorption sites. This latter technique was also used to characterize the sorption of plutonium and neptunium on polished thin-sections of alluvium, granite, tuff, and argillite and to assess the amount of aggregation that occurred. Additional physical and chemical characterizations of the materials used in these studies were made, and new analytical techniques were developed

  20. Distribution of cobalt in soil from Kavadarci and the environs

    International Nuclear Information System (INIS)

    The results of the study of spatial distribution of cobalt in surface soil and subsoil over of the Kavadarci region, Republic of Macedonia, are reported. From the investigated region (360 km2) in total 344 soil samples from 172 locations were collected. At each sampling point soil samples were collected at two depths, topsoil (0-5 cm) and subsoil soil (20-30 cm). Inductively coupled plasma - mass spectrometry (ICP-MS) was applied for the determination of cobalt. Data analysis and construction of the map were performed using the Paradox (ver. 9), Statistica (ver. 6.1), AutoDesk Map (ver. 2008) and Surfer (ver. 8.09) software. It was found that for both topsoil and subsoil the median and average values are 15 mg/kg, ranges between 6.7 and 58 mg/kg. The highest content of cobalt is present in the soil from the area of Paleozoic and Mesozoic rocks (Pz-Mz) on the western part of the investigated area and Flysch (E) - Eocene upper flysch zone (on the northern part) and the lowest in the soils from the Holocene alluvium of the rivers Crna Reka and Vardar. There are no significant differences between the surface and subsoil in terms of its average quantities. It was found that the critically high contents are related primarily to high contents of cobalt in the sampling points from the western part of the investigated region. The contents of cobalt are higher in subsoil than in topsoil from which it can be concluded that the occurrence is natural.

  1. A media-based assessment of damage and ground motions from the january 26th, 2001 M 7.6 Bhuj, India earthquake

    Science.gov (United States)

    Hough, Susan E.; Martin, Stacey; Bilham, Roger; Atkinson, Gail M.

    2003-09-01

    We compiled available news and internet accounts of damage and other effects from the 26th January, 2001, Bhuj earthquake, and interpreted them to obtain modified Mercalli intensities at over 200 locations throughout the Indian subcontinent. These values are used to map the intensity distribution using a simple mathematical interpolation method. The maps reveal several interesting features. Within the Kachchh region, the most heavily damaged villages are concentrated towards the western edge of the inferred fault, consistent with western directivity. Significant sedimentinduced amplification is also suggested at a number of locations around the Gulf of Kachchh to the south of the epicenter. Away from the Kachchh region intensities were clearly amplified significantly in areas that are along rivers, within deltas, or on coastal alluvium such as mud flats and salt pans. In addition we use fault rupture parameters inferred from teleseismic data to predict shaking intensity at distances of 0-1000 km. We then convert the predicted hard rock ground motion parameters to MMI using a relationship (derived from internet-based intensity surveys) that assigns MMI based on the average effects in a region. The predicted MMIs are typically lower by 1-2 units than those estimated from news accounts. This discrepancy is generally consistent with the expected effect of sediment response, but it could also reflect other factors such as a tendency for media accounts to focus on the most dramatic damage, rather than the average effects. Our modeling results also suggest, however, that the Bhuj earthquake generated more high-frequency shaking than is expected for earthquakes of similar magnitude in California, and may therefore have been especially damaging.

  2. Evaluating dryland ecological and river restoration using repeat LiDAR and hydrological monitoring

    Science.gov (United States)

    Henderson, W. M.; DeLong, S.

    2012-12-01

    , both in surface reservoirs and in the alluvium deposited upstream of gabions and berms, plant growth recovers.

  3. Study on the risk and impacts of land subsidence in Jakarta

    Science.gov (United States)

    Abidin, H. Z.; Andreas, H.; Gumilar, I.; Brinkman, J. J.

    2015-11-01

    Jakarta is the capital city of Indonesia located in the west-northern coast of Java island, within a deltaic plain and passes by 13 natural and artificial rivers. This megapolitan has a population of about 10.2 million people inhabiting an area of about 660 km2, with relatively rapid urban development. It has been reported for many years that several places in Jakarta are subsiding at different rates. The main causative factors of land subsidence in Jakarta are most probably excessive groundwater extraction, load of constructions (i.e., settlement of high compressibility soil), and natural consolidation of alluvial soil. Land subsidence in Jakarta has been studied using leveling surveys, GPS surveys, InSAR and Geometric-Historic techniques. The results obtained from leveling surveys, GPS surveys and InSAR technique over the period between 1974 and 2010 show that land subsidence in Jakarta has spatial and temporal variations with typical rates of about 3-10 cm year-1. Rapid urban development, relatively young alluvium soil, and relatively weak mitigation and adapatation initiatives, are risk increasing factors of land subsidence in Jakarta. The subsidence impacts can be seen already in the field in forms of cracking and damage of housing, buildings and infrastructure; wider expansion of (riverine and coastal) flooding areas, malfunction of drainage system, changes in river canal and drain flow systems and increased inland sea water intrusion. These impacts can be categorized into infrastructural, environmental, economic and social impacts. The risk and impacts of land subsidence in Jakarta and their related aspects are discussed in this paper.

  4. Hydro geochemistry Investigation of The (Bursa) Orhangazi Plain and its Environs

    International Nuclear Information System (INIS)

    The study area is located SE of the Armutlu Peninsula. Geological and hydrogeological studies are conducted on 1/25.000 scale maps covering an area of approximately 70 km2. The basement of the region is made up of metagreywacke shale and schist which are overlain by marbles with the extensive karstic features such as caves, polya, etc. The Pliocene aged lacustrine unconformably overlying the marbles are covered with alluvium in Orhangazi plain. At present, the Nadir and Kaynarca springs supply water for the town of Orhangazi. The Nadir spring flows naturally towards the municipality water system whereas the Kaynarca spring water is pumped into the system. These springs are naturally fed by precipitation through the marbles. In order to investigate the velocity of these water sources in the specified direction and their relation with each other, experiments of dye trace, water chemistry and isotopic analyses from hydrochemical point of view were conducted. Based on these observations, it was found that the source area of the Kaynarca and Ilipynar spring waters were to the east and south of the source area of the Nadir spring and that there was no connection between the sources of water to Nadir spring and that of the other two springs. Also, the predominant ions in the source waters are Ca+2 and HCO3-. These are of meteoric origin that are under the effect of annual rains. The effects of the Marmara 17 Agust Earthquake were relatively minor although temporary changes in flow and turbidity occured almost immediatly after the earthquake. The earthquake did not alter the chemistry of the water springs

  5. Hydrogeochemistry for the assessment of groundwater quality in Varanasi: a fast-urbanizing center in Uttar Pradesh, India.

    Science.gov (United States)

    Janardhana Raju, Nandimandalam; Shukla, U K; Ram, Prahlad

    2011-02-01

    The hydrogeochemical parameters for groundwater samples of the Varanasi area, a fast-urbanizing region in India, were studied to evaluate the major ion chemistry, weathering and solute acquisition processes controlling water composition, and suitability of water quality for domestic and irrigation uses. Sixty-eight groundwater samples were collected randomly from dug wells and hand pumps in the urban Varanasi area and analyzed for various chemical parameters. Geologically, the study area comprises Quaternary alluvium made up of an alternating succession of clay, silty clay, and sand deposits. The Total dissolved solids classification reveals that except two locations, the groundwater samples are desirable for drinking, and all are useful for irrigation purposes. The cationic and anionic concentrations indicated that the majority of the groundwater samples belong to the order of Na>Ca>Mg>K and HCO3>Cl>SO4 types, respectively. Geochemical classification of groundwater based on the Chadha rectangular diagram shows that the majority (81%) of groundwater samples belong to the calcium-bicarbonate type. The HCO3/(HCO3+SO4) ratio (0.87) indicates mostly carbonic acid weathering process due to presence of kankar carbonate mixed with clay/fine sand. The high nitrate concentration (>45 mg/l) of about 18% of the groundwater samples may be due to the local domestic sewage, leakage of septic tanks, and improper management of sanitary landfills. In general, the calculated values of sodium adsorption ratio, percent sodium, residual sodium carbonate, and permeability index indicate good to permissible use of water for irrigation, and only a few locations demand remedial measures for better crop yields. PMID:20221794

  6. Soil intervention as a strategy for lead exposure prevention: The New Orleans lead-safe childcare playground project

    International Nuclear Information System (INIS)

    The feasibility of reducing children's exposure to lead (Pb) polluted soil in New Orleans is tested. Childcare centers (median = 48 children) are often located in former residences. The extent of soil Pb was determined by selecting centers in both the core and outlying areas. The initial 558 mg/kg median soil Pb (range 14-3692 mg/kg) decreased to median 4.1 mg/kg (range 2.2-26.1 mg/kg) after intervention with geotextile covered by 15 cm of river alluvium. Pb loading decreased from a median of 4887 μg/m2 (454 μg/ft2) range 603-56650 μg/m2 (56-5263 μg/ft2) to a median of 398 μg/m2 (37 μg/ft2) range 86-980 μg/m2 (8-91 μg/ft2). Multi-Response Permutation Procedures indicate similar (P-values = 0.160-0.231) soil Pb at childcare centers compared to soil Pb of nearby residential communities. At ∼$100 per child, soil Pb and surface loading were reduced within hours, advancing an upstream intervention conceptualization about Pb exposure prevention. - Highlights: → Upstream thinking refers to attending to causative agents that affect outcomes. → New Orleans has a high density soil Pb map of all residential communities. → Many childcare centers are located in Pb polluted residential communities. → Evaluation of childcare center playground soils substantiated severe Pb pollution. → Pursuing upstream thinking, low Pb soil was put on playgrounds to protect children. - Within hours, at a cost of about U.S. $100 (2010) per child, it is feasible to transform exterior play areas at childcare centers from Pb contaminated to Pb-safe with a large margin of safety.

  7. Low-temperature geothermal potential of the Ojo Caliente warm springs area, northern New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Vuataz, F.D.; Stix, J.; Goff, F.; Pearson, C.F.

    1984-05-01

    A detailed geochemical investigation of 17 waters (thermal and cold, mineralized and dilute) was performed in the Ojo Caliente-La Madera area. Two types of thermomineral waters have separate and distinctive geologic, geochemical, and geothermal characteristics. The water from Ojo Caliente Resort emerges with temperatures less than or equal to 54/sup 0/C from a Precambrian metarhyolite. Its chemistry, typically Na-HCO/sub 3/, has a total mineralization of 3600 mg/l. Isotopic studies have shown that the thermal water emerges from the springs and a hot well without significant mixing with the cold shallow aquifer of the valley alluvium. However, the cold aquifer adjacent to the resort does contain varying amounts of thermal water that originates from the warm spring system. Geothermometry calculations indicate that the thermal water may be as hot as 85/sup 0/C at depth before its ascent toward surface. Thermodynamic computations on the reaction states of numerous mineral phases suggest that the thermal water will not cause major scaling problems if the hot water is utilized for direct-use geothermal applications. By means of a network of very shallow holes, temperature and electrical conductivity anomalies have been found elsewhere in the valley around Ojo Caliente, and resistivity soundings have confirmed the presence of a plume of thermal water entering the shallow aquifer. The group of lukewarm springs around La Madera, with temperatures less than or equal to 29/sup 0/C, chemical type of NaCaMg-HCO/sub 3/Cl and with a total mineralization less than or equal to 1500 mg/l behaves as a different system without any apparent relation to the Ojo Caliente system. Its temperature at depth is not believed to exceed 35 to 40/sup 0/C.

  8. Groundwater contamination mechanism in a geothermal field: A case study of Balcova, Turkey

    Science.gov (United States)

    Aksoy, Niyazi; Şimşek, Celalettin; Gunduz, Orhan

    2009-01-01

    The Balcova Geothermal Field (BGF) located in Izmir, Turkey is situated on an east-west directed graben plain within which the hot waters surface from a fault zone that cuts the Mesozoic aged Bornova Flysch. Due to the low permeability and porosity of the Bornova Flysch, the geothermal water cycles along the immediate vicinity of the Agamemnon fault and mixes with cold waters at different depths of this fractured zone. Within the scope of this study, the mixing patterns and the groundwater contamination mechanisms are analyzed by, hydrogeological and hydrogeochemical methods. Based on the results of this research, it has been found out that the hot geothermal water and the cold regional groundwater resources of the surficial aquifer mix within the fractured zone in Bornova Flysch and within the Quaternary alluvium aquifer due to natural and anthropogenic activities including (i) the natural upward movement of geothermal fluid along the fault line, (ii) the accelerated upward seepage of geothermal fluid from faulty constructed boreholes drilled in the area, (iii) the faulty reinjection applications; and, (iv) the uncontrolled discharge of waste geothermal fluid to the natural drainage network. As a result of these activities, the cold groundwater reserves of the alluvial aquifer are contaminated thermally and chemically in such a way that various toxic chemicals including arsenic, antimony and boron are introduced to the heavily used surficial aquifer waters hindering their use for human consumption and agricultural irrigation. Furthermore, the excessive pumping from the surficial aquifer as well as the reduced surface water inflow into BGF due to the dam constructed on Ilica Creek intensify the detrimental effects of this contamination. Based on the results of this study, it can be concluded that the groundwater pollution in BGF will expand and reach to the levels of no return unless a series of preventive measures is taken immediately.

  9. Naghan (Chahar Mahal Bakhtiari-High Zagros, Iran Earthquake of 6 april 1977. A preliminary field report and a seismotectonic discussion

    Directory of Open Access Journals (Sweden)

    M. BERBERIAN

    1978-06-01

    Full Text Available

    The Naghan earthquake of magnitude 6 (Ms occurred on 6 April
    1977 in the mountanious area of Chahar Mahal Bakhtiari in the High
    Zagros, south of Shahr-e-Kord. It killed 348 people, injured about 200,
    and caused destruction over an area of 150 Km2. The shock damaged
    beyond repair 2,100 houses and killed 0.7°/o of livestock in the area;
    eight schools collapsed and 37 were damaged. The maximum intensity
    ot' the main shock did not exceed VIII (MM.
    The earthquake was associated neither with any fresh surface faulting,
    nor with reactivation of the existing faults and salt domes at
    surface. Heavy rain fell before and during the earthquake and the
    destruction was more extensive where the saturated clay content of the
    alluvium was higher; it was also more extensive in water-logged areas
    or the areas with a shallower water table. Landslides occurred on steep
    slopes and destroyed or damaged some villages built on slopes. Several
    aftershocks caused additional damage to the already destroyed or
    damaged villages.
    The Naghan earthquake was another instance of the « subsedimentary
    Zagros-Type Earthquake » in the High Zagros part of the Zagros Active

    Folded Belt, indicating that the re-adjustment of the unexposed metamorphosed
    Precambrian Basement at depth caused no tectonic deformation
    (surface faulting at the top of the sedimentary cover. This was
    due to the presence of the Upper Precambrian Hormoz layers (Salt
    deposits acting as a slippage zone along the decollement surface of the
    Zagros at depth.

  10. Cenozoic stratigraphy and geologic history of the Tucson Basin, Pima County, Arizona

    Science.gov (United States)

    Anderson, S.R.

    1987-01-01

    This report was prepared as part of a geohydrologic study of the Tucson basin conducted by the U.S. Geological Survey in cooperation with the city of Tucson. Geologic data from more than 500 water supply and test wells were analyzed to define characteristics of the basin sediments that may affect the potential for land subsidence induced by groundwater withdrawal. The Tucson basin is a structural depression within the Basin and Range physiographic province. The basin is 1,000 sq mi in units area and trends north to northwest. Three Cenozoic stratigraphic unit--the Pantano Formation of Oligocene age, the Tinaja beds (informal usage) of Miocene and Pliocene age, and the Fort Lowell Formation of Pleistocene age--fill the basin. The Tinaja beds include lower, middle, and upper unconformable units. A thin veneer of stream alluvium of late Quaternary age overlies the Fort Lowell Formation. The Pantano Formation and the lower Tinaja beds accumulated during a time of widespread continental sedimentation, volcanism, plutonism, uplift, and complex faulting and tilting of rock units that began during the Oligocene and continued until the middle Miocene. Overlying sediments of the middle and upper Tinaja beds were deposited in response to two subsequent episodes of post-12-million-year block faulting, the latter of which was accompanied by renewed uplift. The Fort Lowell Formation accumulated during the Quaternary development of modern through-flowing the maturation of the drainage. The composite Cenozoic stratigraphic section of the Tucson basin is at least 20,000 ft thick. The steeply tilted to flat-lying section is composed of indurated to unconsolidated clastic sediments, evaporites, and volcanic rocks that are lithologically and structurally complex. The lithology and structures of the section was greatly affected by the uplift and exhumation of adjacent metamorphic core-complex rocks. Similar Cenozoic geologic relations have been identified in other parts of southern

  11. Duration of nuclear explosion ground motion

    International Nuclear Information System (INIS)

    This paper evaluates the duration of strong ground shaking that results from nuclear explosions and identifies some of the problems associated with its determination. Knowledge of the duration of horizontal ground shaking is important out to epicentral distances of about 44 km and 135 km, the approximate distances at which the ground shaking level falls to 0.01 g for nuclear explosions having yields of about 100 kt and 1,000 kt, respectively. Evaluation of the strong ground motions recorded from the event STRAIT (M/sub L/ = 5.6) on a linear array of five, broad-band velocity seismographs deployed in the distance range 3.2 to 19.5 km provides information about the characteristics of the duration of ground shaking. The STRAIT data show that: (1) the definition that is used for defining duration is very important; (2) the duration of ground acceleration, as defined in terms of 90% of the integral of the squared time history, increased from about 4 to 26 sec over the approximately 20-km distance range; and (3) the duration of ground velocity and displacement were slightly greater because of the effect of the alluvium layer on the propagating surface waves. Data from other events augment the STRAIT data and show that: (1) duration of shaking is increased by frequency-dependent site effects and (2) duration of shaking, as defined by the integral of the squared time history, does not increase as rapidly with increase in yield as is indicated by other definitions of duration that are stated in terms of an amplitude threshold (e.g., bracketed duration, response envelopes). The available data suggest that the duration of ground acceleration, based on the integral definition, varies from about 4 to 40 sec for a 100-kt range explosion and from about 4 to 105 sec for a megaton range explosion in the epicentral distance range of 0 to 44 km and 0 to 135 km, respectively

  12. Geomorphology of the Alluvial Sediments and Bedrock in an Intermontane Basin: Application of Variogram Modeling to Electrical Resistivity Soundings

    Science.gov (United States)

    Khan, Adnan Ahmad; Farid, Asam; Akhter, Gulraiz; Munir, Khyzer; Small, James; Ahmad, Zulfiqar

    2016-05-01

    The study describes a methodology used to integrate legacy resistivity data with limited geological data in order to build three-dimensional models of the near subsurface. Variogram analysis and inversion techniques more typically found in the petroleum industry are applied to a set of 1D resistivity data taken from electrical surveys conducted in the 1980s. Through careful integration with limited geological data collected from boreholes and outcrops, the resultant model can be visualized in three dimensions to depict alluvium layers as lithological and structural units within the bedrock. By tuning the variogram parameters to account for directionality, it is possible to visualize the individual lithofacies and geomorphological features in the subsurface. In this study, an electrical resistivity data set collected as part of a groundwater study in an area of the Peshawar basin in Pakistan has been re-examined. Additional lithological logs from boreholes throughout the area have been combined with local outcrop information to calibrate the data. Tectonic activity during the Himalayan orogeny has caused uplift in the area and generated significant faulting in the bedrock resulting in the formation of depressions which are identified by low resistivity values representing clays. Paleo-streams have reworked these clays which have been eroded and replaced by gravel-sand facies along paleo-channels. It is concluded that the sediments have been deposited as prograding fan-shaped bodies and lacustrine deposits with interlayered gravel-sand and clay-silt facies. The Naranji area aquifer system has thus been formed as a result of local tectonic activity with fluvial erosion and deposition and is characterized by coarse sediments with high electrical resistivities.

  13. Occurrence of phosphorus in groundwater and surface water of northwestern Mississippi

    Science.gov (United States)

    Welch, Heather L.; Kingsbury, James A.; Coupe, Richard H.

    2010-01-01

    Previous localized studies of groundwater samples from the Mississippi River Valley alluvial (MRVA) aquifer have demonstrated that dissolved phosphorus concentrations in the aquifer are much higher than the national background concentration of 0.03 milligram per liter (mg/L) found in 400 shallow wells across the country. Forty-six wells screened in the MRVA aquifer in northwestern Mississippi were sampled from June to October 2010 to characterize the occurrence of phosphorus in the aquifer, as well as the factors that might contribute to high dissolved phosphorus concentrations in groundwater. Dissolved phosphorus concentrations ranged from 0.12 to 1.2 mg/L with a median concentration of 0.62 mg/L. The predominant subunit of the MRVA aquifer in northwestern Mississippi is the Holocene alluvium in which median dissolved phosphorus concentrations were higher than the Pleistocene valley trains deposits subunit. Highest phosphorus concentrations occurred in water from wells located along the Mississippi River. A general association between elevated phosphorus concentrations and dissolved iron concentrations suggests that reducing conditions that mobilize iron in the MRVA aquifer also might facilitate transport of phosphorus. Using baseflow separation to estimate the contribution of baseflow to total streamflow, the estimated contribution to the total phosphorus load associated with baseflow at the Tensas River at Tendal, LA, and at the Bogue Phalia near Leland, MS, was 23 percent and 8 percent, respectively. This analysis indicates that elevated concentrations of dissolved phosphorus in the MRVA aquifer could be a possible source of phosphorus to streams during baseflow conditions. However, the fate of phosphorus in groundwater discharge and irrigation return flow to streams is not well understood.

  14. Soil intervention as a strategy for lead exposure prevention: The New Orleans lead-safe childcare playground project

    Energy Technology Data Exchange (ETDEWEB)

    Mielke, Howard W., E-mail: howard.mielke@gmail.com [Department of Chemistry, Tulane University, New Orleans, LA 70118 (United States); Center for Bioenvironmental Research at Tulane and Xavier Universities, 1430 Tulane Avenue SL-3, New Orleans, LA 70112 (United States); Covington, Tina P. [Charity School of Nursing, Delgado Community College, New Orleans, LA 70112-1397 (United States); College of Nursing, University of South Alabama, Doctor of Nursing Practice Program (student), Mobile AL 36688-0002 (United States); Mielke, Paul W. [Department of Statistics, Colorado State University, Fort Collins, CO 80523-1877 (United States); Wolman, Fredericka J. [Director of Pediatrics, Department of Children and Families, State of Connecticut, Hartford, CT 06473 (United States); Powell, Eric T.; Gonzales, Chris R. [Lead Lab, Inc., New Orleans, LA 70179-1125 (United States)

    2011-08-15

    The feasibility of reducing children's exposure to lead (Pb) polluted soil in New Orleans is tested. Childcare centers (median = 48 children) are often located in former residences. The extent of soil Pb was determined by selecting centers in both the core and outlying areas. The initial 558 mg/kg median soil Pb (range 14-3692 mg/kg) decreased to median 4.1 mg/kg (range 2.2-26.1 mg/kg) after intervention with geotextile covered by 15 cm of river alluvium. Pb loading decreased from a median of 4887 {mu}g/m{sup 2} (454 {mu}g/ft{sup 2}) range 603-56650 {mu}g/m{sup 2} (56-5263 {mu}g/ft{sup 2}) to a median of 398 {mu}g/m{sup 2} (37 {mu}g/ft{sup 2}) range 86-980 {mu}g/m{sup 2} (8-91 {mu}g/ft{sup 2}). Multi-Response Permutation Procedures indicate similar (P-values = 0.160-0.231) soil Pb at childcare centers compared to soil Pb of nearby residential communities. At {approx}$100 per child, soil Pb and surface loading were reduced within hours, advancing an upstream intervention conceptualization about Pb exposure prevention. - Highlights: > Upstream thinking refers to attending to causative agents that affect outcomes. > New Orleans has a high density soil Pb map of all residential communities. > Many childcare centers are located in Pb polluted residential communities. > Evaluation of childcare center playground soils substantiated severe Pb pollution. > Pursuing upstream thinking, low Pb soil was put on playgrounds to protect children. - Within hours, at a cost of about U.S. $100 (2010) per child, it is feasible to transform exterior play areas at childcare centers from Pb contaminated to Pb-safe with a large margin of safety.

  15. Geophysical surveys at the UMTRA project Shiprock, New Mexico site

    Energy Technology Data Exchange (ETDEWEB)

    Wightman, E.; Smith, B.; Newlin, B.

    1996-03-01

    Geophysical surveys were performed at the Uranium Mill Tailings Remedial Action (UMTRA) Shiprock site in New Mexico during February 1996. The surveys were designed to locate areas of ground water contamination, consisting largely of sulfate and nitrate salts and uranium. Electrical geophysical methods were used to locate areas of sulfate and nitrate concentrations since these products, when present in ground water, increase its electrical conductivity. These contaminants also increase the density of water, making the water with the highest concentrations of these salts sink to the bottom of the water column. At the Shiprock site, where alluvium is underlain by the impervious Mancos Shale, the saline water will tend to rest in depressions on the shale surface. Seismic refraction surveys were conducted on the floodplain. The site comprises two areas, the terrace and the floodplain, separated by a steep scarp of some 70 feet (ft) (20 meters [m]). Measurements of electrical conductivity were taken over these two areas, searching for possible pockets of saline ground water resting on top of the bedrock. Conductivity surveys were also run to identify fractures within the bedrock that may act as conduits for ground water movement. Several areas of higher than normal conductivity were found on the terrace, including halos of higher conductivities on three sides of the tailings cell. The conductivity measurements searching for fractures found only a small number of minor fracture-like anomalies. These are not considered important. On the floodplain, both conductivity and seismic refraction measurements were taken. The conductivity measurements clearly show areas of high conductivity interpreted to result from ground water contamination. The seismic refraction measurements identified bedrock depressions that may contain denser, and more saline ground water lenses. Generally, the areas of high conductivity coincide with the bedrock depressions.

  16. Selected hydrologic data from Fortymile Wash in the Yucca Mountain area, Nevada, water year 1992

    Energy Technology Data Exchange (ETDEWEB)

    Savard, C.S.

    1995-02-01

    Precipitation totals of 245 and 210 mm were measured at UE-29 UZN {number_sign}91 and UE-29 UZN {number_sign}92 respectively, during the 1992 water year, October 1, 1991 to September 30, 1992. Approximately ninety percent of the precipitation fell during the period December 27 to April 2. Localized streamflow was generated in the Fortymile Wash drainage basin during the February 12-15, 1992 and March 31, 1992 precipitation, and infiltrated into the streambed materials. The streamflow went across the UE-29 UZN {number_sign}91 neutron-access borehole location and within several meters of the UE-29 UZN {number_sign}92 location. Neutron logging in these boreholes showed increases in the volumetric water content of the unsaturated alluvium and indicated streamflow infiltrated to a depth of approximately 5 meters. The volumetric water content in the upper 5 meters then gradually decreased during the remaining part of the water year. Ground-water levels rose over one meter in wells UE-29 a{number_sign}1 and UE-29 a{number_sign}2, and one-half meter in neutron-access borehole LJE-29 UZN {number_sign}91 following the streamflows. Water level declines of 0.5 meter in UE-29 a{number_sign}1 and rises of 0.2 meter in UE-29 a{number_sign}2 and 0.1 meter in UE-29 UZN {number_sign}91 coincided with a June 29, 1992 earthquake at the Little Skull Mountain, located approximately 27 kilometers southeast of the wells.

  17. Sinkhole susceptibility mapping using the analytical hierarchy process (AHP) and magnitude-frequency relationships: A case study in Hamadan province, Iran

    Science.gov (United States)

    Taheri, Kamal; Gutiérrez, Francisco; Mohseni, Hassan; Raeisi, Ezzat; Taheri, Milad

    2015-04-01

    Since 1989, an increasing number of sinkhole occurrences have been reported in the Kabudar Ahang and Razan-Qahavand subcatchments (KRQ) of Hamadan province, western Iran. The sinkhole-related subsidence phenomenon poses a significant threat for people and human structures, including sensitive facilities like the Hamadan Power Plant. Groundwater over-exploitation from the thick alluvial cover and the underlying cavernous limestone has been identified as the main factor involved in sinkhole development. A sinkhole susceptibility model was produced in a GIS environment applying the analytical hierarchy process (AHP) approach and considering a selection of eight factors, each categorized into five classes: distance to faults (DF), water level decline (WLD), groundwater exploitation (GE), penetration of deep wells into karst bedrock (PKA), distance to deep wells (DDW), groundwater alkalinity (GA), bedrock lithology (BL), and alluvium thickness (AT). Relative weights were preliminarily assigned to each factor and to their different classes through systematic pairwise comparisons based on expert judgment. The resulting sinkhole susceptibility index (SSI) values were then classified into four susceptibility classes: low, moderate, high and very high susceptibility. Subsequently, the model was refined through a trial and error process involving changes in the relative weights and iterative evaluation of the prediction capability. Independent evaluation of the final model indicates that 55% and 45% of the subsidence events fall within the very high and high, susceptibility zones, respectively. The results of this study show that AHP can be a useful approach for susceptibility assessment if data on the main controlling factors have sufficient accuracy and spatial coverage. The limitations of the model are partly related to the difficulty of gathering data on some important geological factors, due to their hidden nature. The magnitude and frequency relationship constructed

  18. Changes of Natural Processes in the Volga-Akhtuba Floodplain and Balta Braila of Lower Danube

    Directory of Open Access Journals (Sweden)

    Brylev Viktor Andreevich

    2015-09-01

    Full Text Available In the second half of the twentieth century, the Volga and the Danube were regulated. As a result, channel processes and the processes of alluvium deposition and humus accumulation in soils, surface and underground waters were changed. The comparative analysis of Volga-Akhtuba and Lower Dunabe floodplains is carried out in the article. It was found that due to the regulated flow, hydraulic engineering and land reclamation construction had provoked direct (immediate changes in natural systems, as well as indirect (mediated changes in the landscapes. The Volga-Akhtuba floodplain is characterized by the dominance of indirect effects resulting from changes in the hydrological regime of the Volga to produce cheap electricity and irrigation of vegetable plantations. Therefore, the landscape can be attributed to the natural type. The Lower Danube is characterized by immediate impact, namely, leveling the surface and creating a drainage system, the purpose of which was to increase the area of agricultural land within the floodplain and to decrease the number of catastrophic floods. This led to the formation of technogenically anthropogenic landscape within the floodplain. The components and relationships in the downstream of the Volga hydroelectric are degraded, but not destroyed in comparison with the Great Balta Braila, so the natural complexes of the Volga-Akhtuba floodplain and associated natural processes can be restored by means of environmental management. Abnormalities in the flow regulation of the Volga and the Danube led to the destruction of hydraulic connection between the two bodies of water floodplains, alluvial processes slow down and change in the level of groundwater. Within the floodplain the erosion and accumulation also lowered their rates. The river channels, on the contrary, increased erosion and accumulation, causing the decrease of rivers level, and there is an active formation of braid, shoals and islands.

  19. Paleofloristic and paleofaunistic analysis of Dudváh River oxbow and implication for Late Holocene paleoenvironmental development of the Žitný ostrov Island (SW Slovakia)

    Science.gov (United States)

    Pišút, Peter; Břízová, Eva; Čejka, Tomáš; Pipík, Radovan

    2010-12-01

    Žitný ostrov, the largest island of the Danube River (SW Slovakia) gained its present shape in the Neoholocene period. As a result of increased flood and geomorphological Danube river activity dated to 1378-1528 AD, the Lower Dudváh River was abandoned and its alluvium became a part of the Žitný ostrov. Study of a Dudváh terrestrialized paleomeander by means of pollen and macrofossil analysis provides new information about the paleoenvironments of the Danubian Plain. The meander under study was cut-off during the Sub-Boreal period when the land was mostly covered by oak-dominated mixed forest with a notable high frequency of Fagus and Abies. In low-lying depressions, Alnus glutinosa formed typical alder carrs. The largest decline of the mixed forest occurred during the Sub-Atlantic period. Until the mid-19th century the region was strongly influenced by shallow groundwater and periodical floods, as reflected by pollen of aquatics and marsh species. Amongst non-arboreal taxa, pollen of Cyperaceae, Brassicaceae/Cuscuta, Poaceae and Apiaceae prevailed. Local successional changes started with i) stage of abandoned oxbow still with influx of moving water, poor in both macrophytes and molluscs, ii) shallow eutrophic oxbow lake with slowly flowing or stagnant water overgrown with aquatics (Ranunculus subgen. Batrachium, Potamogeton sp., Ceratophyllum demersum etc.) and abundant molluscs, iii) an open marsh dominated by Cyperaceae (mainly Carex riparia) with Atriplex prostrata, supporting diverse molluscan and Ostracod fauna. Present-day habitat is a result of landscape changes, which have been associated with draining, intensified agriculture, ruderalisation and spread of invasive species.

  20. A strategy to seal exploratory boreholes in unsaturated tuff; Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, J.A. [Sandia National Labs., Albuquerque, NM (United States); Case, J.B.; Givens, C.A.; Carney, B.C. [IT Corp., Albuquerque, NM (United States)

    1994-04-01

    This report presents a strategy for sealing exploratory boreholes associated with the Yucca Mountain Site Characterization Project. Over 500 existing and proposed boreholes have been considered in the development of this strategy, ranging from shallow (penetrating into alluvium only) to deep (penetrating into the groundwater table). Among the comprehensive list of recommendations are the following: Those boreholes within the potential repository boundary and penetrating through the potential repository horizon are the most significant boreholes from a performance standpoint and should be sealed. Shallow boreholes are comparatively insignificant and require only nominal sealing. The primary areas in which to place seals are away from high-temperature zones at a distance from the potential repository horizon in the Paintbrush nonwelded tuff and the upper portion of the Topopah Spring Member and in the tuffaceous beds of the Calico Hills Unit. Seals should be placed prior to waste emplacement. Performance goals for borehole seals both above and below the potential repository are proposed. Detailed construction information on the boreholes that could be used for future design specifications is provided along with a description of the environmental setting, i.e., the geology, hydrology, and the in situ and thermal stress states. A borehole classification scheme based on the condition of the borehole wall in different tuffaceous units is also proposed. In addition, calculations are presented to assess the significance of the boreholes acting as preferential pathways for the release of radionuclides. Design calculations are presented to answer the concerns of when, where, and how to seal. As part of the strategy development, available technologies to seal exploratory boreholes (including casing removal, borehole wall reconditioning, and seal emplacement) are reviewed.

  1. Selected hydrologic data from Fortymile Wash in the Yucca Mountain area, Nevada, water year 1992

    International Nuclear Information System (INIS)

    Precipitation totals of 245 and 210 mm were measured at UE-29 UZN number-sign 91 and UE-29 UZN number-sign 92 respectively, during the 1992 water year, October 1, 1991 to September 30, 1992. Approximately ninety percent of the precipitation fell during the period December 27 to April 2. Localized streamflow was generated in the Fortymile Wash drainage basin during the February 12-15, 1992 and March 31, 1992 precipitation, and infiltrated into the streambed materials. The streamflow went across the UE-29 UZN number-sign 91 neutron-access borehole location and within several meters of the UE-29 UZN number-sign 92 location. Neutron logging in these boreholes showed increases in the volumetric water content of the unsaturated alluvium and indicated streamflow infiltrated to a depth of approximately 5 meters. The volumetric water content in the upper 5 meters then gradually decreased during the remaining part of the water year. Ground-water levels rose over one meter in wells UE-29 a number-sign 1 and UE-29 a number-sign 2, and one-half meter in neutron-access borehole LJE-29 UZN number-sign 91 following the streamflows. Water level declines of 0.5 meter in UE-29 a number-sign 1 and rises of 0.2 meter in UE-29 a number-sign 2 and 0.1 meter in UE-29 UZN number-sign 91 coincided with a June 29, 1992 earthquake at the Little Skull Mountain, located approximately 27 kilometers southeast of the wells

  2. Application of HydroGeoSphere to model the response to anthropogenic climate change of three-dimensional hydrological processes in the geologically, geothermally, and topographically complex Valles Caldera super volcano, New Mexico: Preliminary results

    Science.gov (United States)

    Wine, M.; Cadol, D. D.

    2014-12-01

    Anthropogenic climate change is expected to reduce streamflow in the southwestern USA due to reduction in precipitation and increases in evaporative demand. Understanding the effects of climate change in this region is particularly important for mountainous areas since these are primary sources of recharge in arid and semi-arid environments. Therefore we undertook to model effects of climate change on the hydrological processes in Valles Caldera (448 km2), located in the Jemez Mountains of northern New Mexico. In Valles Caldera modeling the surficial, hydrogeological, and geothermal processes that influence hydrologic fluxes each present challenges. The surficial dynamics of evaporative demand and snowmelt both serve to control recharge dynamics, but are complicated by the complex topography and spatiotemporal vegetation dynamics. Complex factors affecting evaporative demand include leaf area index, temperature, albedo, and radiation affected by topographic shading; all of these factors vary in space and time. Snowmelt processes interact with evaporative demand and geology to serve as an important control on streamflow generation, but modeling the effects of spatiotemporal snow distributions on streamflow generation remains a challenge. The complexity of Valles Caldera's geology—and its associated hydraulic properties—rivals that of its surficial hydrologic forcings. Hydrologically important geologic features that have formed in the Valles Caldera are three-dimensionally intricate and include a dense system of faults, alluvium, landslides, lake deposits, and features associated with the eruption and collapse of this super volcano. Coupling geothermally-driven convection to the hydrologic cycle in this still-active geothermal system presents yet an additional challenge in modeling Valles Caldera. Preliminary results from applying the three-dimensional distributed hydrologic finite element model HydroGeoSphere to a sub-catchment of Valles Caldera will be

  3. Controls on matrix flow, preferential flow and deep drainage rates in an alluvial Vertisol.

    Science.gov (United States)

    Arnold, Sven; Larsen, Joshua; Reading, Lucy; Finch, Warren; Bulovic, Nevenka; McIntyre, Neil

    2016-04-01

    Deep drainage is the process that describes water percolating from the land surface to a depth below the root zone where it may contribute to groundwater recharge. Quantitative estimation of deep drainage through Vertisols is challenging, largely due to the unknown relative contributions from: (i) flow through the soil matrix; and (ii) flow along preferential pathways in particular soil cracks, and how to model the transience of the relative contributions. The Condamine River Alluvium, a significant aquifer in semi-arid eastern Australia, is mostly covered by uniform dark cracking clays such as Black and Grey Vertisols. The aim of this study was to identify the environmental conditions (rainfall, antecedent soil moisture, etc) controlling matrix and preferential flow in selected Vertisol profiles at the time scale of individual rainfall events. Field experiments (including 16 probes recording soil moisture at one hour intervals across eight depths between 100 mm and 4000 mm) provide extensive soil moisture data, supplemented by weather station data collected at 15-minute intervals. In addition, laboratory experiments were used to infer the water retention curves. These data were used to (i) derive deep drainage rates using the zero-flux plane method, and (ii) calibrate a soil moisture balance model that represents both matrix and preferential flow. The model was used to estimate the parts of the vertical water flux attributed to soil matrix and preferential flow. High antecedent soil moisture was associated with low fluxes at shallow depths, however at deeper depths both low and high antecedent soil moisture were associated with larger fluxes. Further, both rainfall amount and intensity controlled the interplay between matrix and preferential flow. The results reveal new insights into deep drainage processes in Vertisols and provide the basis for developing a practical approach for deep drainage estimation.

  4. Mineralogical discrimination of the pleistocene loess/paleosol sections in Srijem and Baranja, Croatia

    Science.gov (United States)

    Galović, Lidija; Peh, Zoran

    2016-06-01

    Previous investigations of the mineralogical composition of loess sections (loess, loess-like sediments, paleosols, alluvial intercalations) in the Carpathian Basin have concluded that the Danube River is the dominant control on the loessitic parent material. These investigations also identify a significant role for the Danube's tributaries in creating local variations. The north-south alignment of these sections forms a transect from the central part of the Carpathian Basin to its southern edge. In this work, the mineral origin of loess sediments was identified by using the multivariate statistical method of discriminant function analysis. Two models were constructed based on the modal composition as the suite of predictor (independent) variables: one is using geographic location as the a priori grouping criterion (SECTION); another employing the difference between the sampling media (LITHOLOGY). Both of the examined discriminant models demonstrate the existence of the mixing zones. The Erdut section is a clear mixture of the mineralogies at the other studied locations, while loesses appear generally intermediate in mineralogy between alluvium and paleosol. The main rationale for the observed difference in modal composition between the Šarengrad and other analyzed sections is the proximity of the Šarengrad section to the Sava River floodplain and Dinaric Ophiolite Zone (DOZ), both important source areas for aeolian sediments in the southern edge of the Carpathian Basin that transport material from the Central Bosnian Mountains unit of DOZ. Chemically, the most resistant heavy minerals together with opaque minerals are exclusively associated with paleosols, being typical products of geochemical pedogenic processes.

  5. Riola release report

    International Nuclear Information System (INIS)

    Eleven hours after execution of the Riola Event (at 0826 PDT on 25 September 1980) in hole U2eq of the Nevada Test Site (NTS), a release of radioactivity began. When the seepage stopped at about noon the following day, up to some 3200 Ci of activity had been dispersed by light variable winds. On 26 September, examination of the geophone records showed six hours of low-level, but fairly continuous, activity before the release. Electrical measurements indicated that most cables were still intact to a depth below the stemming platform. A survey of the ground zero area showed that the seepage came through cracks between the surface conductor and the pad, through cracks in the pad, and through a crack adjacent to the pad around the mousehole (a small hole adjacent to the emplacement hole). To preclude undue radiation exposure or injury from a surprise subsidence, safety measures were instituted. Tritium seepage was suffucient to postpone site activities until a box and pipeline were emplaced to contain and remove the gas. Radiation release modeling and calculations were generally consistent with observations. Plug-hole interaction calculations showed that the alluvium near the bottom of the plug may have been overstressed and that improvements in the design of the plug-medium interface can be made. Experimental studies verified that the surface appearance of the plug core was caused by erosion, but, assuming a normal strength for the plug material, that erosion alone could not account for the disappearance of such a large portion of the stemming platform. Samples from downhole plug experiments show that the plug may have been considerably weaker than had been indicted by quality assurance (QA) samples. 19 references, 32 figures, 10 tables

  6. Geologic Map of The Volcanoes Quadrangle, Bernalillo and Sandoval Counties, New Mexico

    Science.gov (United States)

    Thompson, Ren A.; Shroba, Ralph R.; Menges, Christopher M.; Schmidt, Dwight L.; Personius, Stephen F.; Brandt, Theodore R.

    2009-01-01

    This geologic map, in support of the U.S. Geological Survey Middle Rio Grande Basin Geologic Mapping Project, shows the spatial distribution of surficial deposits, lava flows, and related sediments of the Albuquerque volcanoes, upper Santa Fe Group sediments, faults, and fault-related structural features. These deposits are on, along, and beneath the Llano de Albuquerque (West Mesa) west of Albuquerque, New Mexico. Some of these deposits are in the western part of Petroglyph National Monument. Artificial fill deposits are mapped chiefly beneath and near the City of Albuquerque Soil Amendment Facility and the Double Eagle II Airport. Alluvial deposits were mapped in and along stream channels, beneath terrace surfaces, and on the Llano de Albuquerque and its adjacent hill slopes. Deposits composed of alluvium and colluvium are also mapped on hill slopes. Wedge-shaped deposits composed chiefly of sandy sheetwash deposits, eolian sand, and intercalated calcic soils have formed on the downthrown-sides of faults. Deposits of active and inactive eolian sand and sandy sheetwash deposits mantle the Llano de Albuquerque. Lava flows and related sediments of the Albuquerque volcanoes were mapped near the southeast corner of the map area. They include eleven young lava flow units and, where discernable, associated vent and near-vent pyroclastic deposits associated with cinder cones. Upper Santa Fe Group sediments are chiefly fluvial in origin, and are well exposed near the western boundary of the map area. From youngest to oldest they include a gravel unit, pebbly sand unit, tan sand and mud unit, tan sand unit, tan sand and clay unit, and silty sand unit. Undivided upper Santa Fe Group sediments are mapped in the eastern part of the map area. Faults were identified on the basis of surface expression determined from field mapping and interpretation of aeromagnetic data where concealed beneath surficial deposits. Fault-related structural features are exposed and were mapped near

  7. Aeolian Processes and Landforms in River Valleys of Central Russian Plain in MIS 2

    Science.gov (United States)

    Matlakhova, Ekaterina

    2015-04-01

    Late Pleistocene terraces in river valleys of Central Russian Plain were subject to aeolian reworking after the alluvial sedimentation had finished. Severe natural conditions of LGM (cold and dry climate, scarce vegetation) contributed activation of aeolian processes. Ground water lowering because of deep pre-LGM incision of rivers made deep aeolian reworking possible at low hypsometric levels of valley bottom. We studied lithological structure of terraces in river valleys of Central Russian Plain. The key sites were located in Seim (the middle Dnieper catchment) and Khoper (the middle Don catchment) river valleys. Field data was combined with quartz grains morphoscopy technique (study of texture of sediment particles using scanning electron microscope). Wide participation of aeolian sediments in terrace deposits was detected. During this study a new technique of the distinguishing of short-term aeolian reworking of alluvial deposits using quartz grains morphoscopy technique was developed. The main problem of interpretation the results of quartz grains morphoscopy is that aeolian signals are sometimes not clear due to short duration of wind action over alluvial sands. However, detailed studies of the quartz grains surfaces under scanning electron microscope helped to solve this problem. We used scanning electron microscope JEOL JSM-661 LV and worked with magnification from ×160 to ×400 for whole grains and up to ×1800 for some parts of grains. Deep aeolian reworking of Late Pleistocene terrace alluvium in river valleys of Central Russian Plain during LGM led to the formation of aeolian covers on the terrace surfaces. Also there are many relict dunes on Late Pleistocene river terrace surfaces. Sometimes the development of aeolian processes could led to more significant changes in the shape of the valley and formation of aeolian aprons. The thickness of aeolian covers can reach 3-5 m or more. Due to this reason morphology and topography of river terraces could

  8. Groundwater contamination mechanism in a geothermal field: a case study of Balcova, Turkey.

    Science.gov (United States)

    Aksoy, Niyazi; Simşek, Celalettin; Gunduz, Orhan

    2009-01-01

    The Balcova Geothermal Field (BGF) located in Izmir, Turkey is situated on an east-west directed graben plain within which the hot waters surface from a fault zone that cuts the Mesozoic aged Bornova Flysch. Due to the low permeability and porosity of the Bornova Flysch, the geothermal water cycles along the immediate vicinity of the Agamemnon fault and mixes with cold waters at different depths of this fractured zone. Within the scope of this study, the mixing patterns and the groundwater contamination mechanisms are analyzed by, hydrogeological and hydrogeochemical methods. Based on the results of this research, it has been found out that the hot geothermal water and the cold regional groundwater resources of the surficial aquifer mix within the fractured zone in Bornova Flysch and within the Quaternary alluvium aquifer due to natural and anthropogenic activities including (i) the natural upward movement of geothermal fluid along the fault line, (ii) the accelerated upward seepage of geothermal fluid from faulty constructed boreholes drilled in the area, (iii) the faulty reinjection applications; and, (iv) the uncontrolled discharge of waste geothermal fluid to the natural drainage network. As a result of these activities, the cold groundwater reserves of the alluvial aquifer are contaminated thermally and chemically in such a way that various toxic chemicals including arsenic, antimony and boron are introduced to the heavily used surficial aquifer waters hindering their use for human consumption and agricultural irrigation. Furthermore, the excessive pumping from the surficial aquifer as well as the reduced surface water inflow into BGF due to the dam constructed on Ilica Creek intensify the detrimental effects of this contamination. Based on the results of this study, it can be concluded that the groundwater pollution in BGF will expand and reach to the levels of no return unless a series of preventive measures is taken immediately.

  9. A media-based assessment of damage and ground motions from the January 26th, 2001 M 7.6 Bhuj, India earthquake

    Science.gov (United States)

    Hough, S.E.; Martin, S.; Bilham, R.; Atkinson, G.M.

    2003-01-01

    We compiled available news and internet accounts of damage and other effects from the 26th January, 2001, Bhuj earthquake, and interpreted them to obtain modified Mercalli intensities at over 200 locations throughout the Indian subcontinent. These values are used to map the intensity distribution using a simple mathematical interpolation method. The maps reveal several interesting features. Within the Kachchh region, the most heavily damaged villages are concentrated towards the western edge of the inferred fault, consistent with western directivity. Significant sediment-induced amplification is also suggested at a number of locations around the Gulf of Kachchh to the south of the epicenter. Away from the Kachchh region intensities were clearly amplified significantly in areas that are along rivers, within deltas, or on coastal alluvium such as mud flats and salt pans. In addition we use fault rupture parameters inferred from teleseismic data to predict shaking intensity at distances of 0-1000 km. We then convert the predicted hard rock ground motion parameters to MMI using a relationship (derived from internet-based intensity surveys) that assigns MMI based on the average effects in a region. The predicted MMIs are typically lower by 1-2 units than those estimated from news accounts. This discrepancy is generally consistent with the expected effect of sediment response, but it could also reflect other factors such as a tendency for media accounts to focus on the most dramatic damage, rather than the average effects. Our modeling results also suggest, however, that the Bhuj earthquake generated more high-frequency shaking than is expected for earthquakes of similar magnitude in California, and may therefore have been especially damaging.

  10. A media-based assessment of damage and ground motions from the January 26th, 2001 M7.6 Bhuj, India earthquake

    Indian Academy of Sciences (India)

    Susan E Hough; Stacey Martin; Roger Bilham; Gail M Atkinson

    2003-09-01

    We compiled available news and internet accounts of damage and other effects from the 26th January, 2001, Bhuj earthquake, and interpreted them to obtain modified Mercalli intensities at over 200 locations throughout the Indian subcontinent. These values are used to map the intensity distribution using a simple mathematical interpolation method. The maps reveal several interesting features. Within the Kachchh region, the most heavily damaged villages are concentrated towards the western edge of the inferred fault, consistent with western directivity. Significant sediment- induced amplification is also suggested at a number of locations around the Gulf of Kachchh to the south of the epicenter. Away from the Kachchh region intensities were clearly amplified significantly in areas that are along rivers, within deltas, or on coastal alluvium such as mud flats and salt pans. In addition we use fault rupture parameters inferred from teleseismic data to predict shaking intensity at distances of 0-1000 km. We then convert the predicted hard rock ground motion parameters to MMI using a relationship (derived from internet-based intensity surveys) that assigns MMI based on the average effects in a region. The predicted MMIs are typically lower by 1-2 units than those estimated from news accounts. This discrepancy is generally consistent with the expected effect of sediment response, but it could also reflect other factors such as a tendency for media accounts to focus on the most dramatic damage, rather than the average effects. Our modeling results also suggest, however, that the Bhuj earthquake generated more high-frequency shaking than is expected for earthquakes of similar magnitude in California, and may therefore have been especially damaging.

  11. Analytical results of a long-term aquifer test conducted near the Rio Grande, Albuquerque, New Mexico, with a section on piezometric-extensometric test results

    Science.gov (United States)

    Thorn, Conde R.; Heywood, Charles E.

    2001-01-01

    The City of Albuquerque, New Mexico, is interested in gaining a better understanding, both quantitative and qualitative, of the aquifer system in and around Albuquerque. Currently (2000), the City of Albuquerque and surrounding municipalities are completely dependent on ground-water reserves for their municipal water supply. This report presents the results of a long-term aquifer test conducted near the Rio Grande in Albuquerque. The long-term aquifer test was conducted during the winter of 1994-95. The City of Albuquerque Griegos 1 water production well was pumped continuously for 54 days at an average pumping rate of 2,331 gallons per minute. During the 54-day pumping and a 30-day recovery period, water levels were recorded in a monitoring network that consisted of 3 production wells and 19 piezometers located at nine sites. These wells and piezometers were screened in river alluvium and (or) the upper and middle parts of the Santa Fe Group aquifer system. In addition to the measurement of water levels, aquifer-system compaction was monitored during the aquifer test by an extensometer. Well-bore video and flowmeter surveys were conducted in the Griegos 1 water production well at the end of the recovery period to identify the location of primary water- producing zones along the screened interval. Analytical results from the aquifer test presented in this report are based on the methods used to analyze a leaky confined aquifer system and were performed using the computer software package AQTESOLV. Estimated transmissivities for the Griegos 1 and 4 water production wells ranged from 10,570 to 24,810 feet squared per day; the storage coefficient for the Griegos 4 well was 0.0025. A transmissivity of 13,540 feet squared per day and a storage coefficient of 0.0011 were estimated from the data collected from a piezometer completed in the production interval of the Griegos 1 well.

  12. Influence of aerodynamic roughness length on aeolian processes: Earth, Mars, Venus

    Science.gov (United States)

    Blumberg, Dan G.; Greeley, Ronald

    1992-01-01

    The aerodynamic roughness length (z sub 0) is the height at which a wind profile assumes a zero velocity. The lower part of the atmospheric boundary layer will be impeded by friction with the surface. An increase in surface roughness will also increase the shear stress required to initiate particle entrainment by the wind. Bagnold (1941) estimated z sub 0 as being 1/30 of the mean particle size. In Nature, surface roughness is composed of nonerodible elements as well as sand-size erodible particles. To assess z sub 0 values as a function of terrain, field experiments were conducted to obtain wind profiles monitored over natural surfaces at 15 sites in the Mojave Desert, Death Valley, and Nye County, Nevada. These sites span a variety of arid-land terrains, including smooth playas, alluvial fans, and lava flows; z sub 0 values ranged from 0.0001 cm to 1 cm. These values were incorporated in a threshold model and a flux model to assess transport efficiency over such terrains in three planetary environments (Venus, Earth, and Mars), and for particle sizes ranging from 60-500 micron. Threshold and flux are a function of planetary environment, particle density and size (Dp), and z sub 0, and the shear velocity of 1.2 x U sub *t (for Dp = 250 micron and z sub 0 = 0.84). Results show that flux on Mars is approximately 14 g/(cm x s), on Earth it is approximately 3 g/(cm x s), and on Venus 0.5 g/(cm x s). Under all planetary environments, the results also show a dramatic decrease in the flux for particles greater than 200 microns when z sub 0 increases above 0.0085 cm (corresponding to sites consisting of alluvium). When z sub 0 approaches 0.03 cm (corresponding to a mantled pahoehoe lava), the flux diminishes.

  13. Aeromagnetic Survey of the Amargosa Desert, Nevada and California: A Tool for Understanding Near-Surface Geology and Hydrology

    Science.gov (United States)

    Blakely, Richard J.; Langenheim, V.E.; Ponce, David A.; Dixon, Gary L.

    2000-01-01

    A high-resolution aeromagnetic survey of the Amargosa Desert and surrounding areas provides insights into the buried geology of this structurally complex region. The survey covers an area of approximately 7,700 km2 (2,970 mi2), extending from Beatty, Nevada, to south of Shoshone, California, and includes parts of the Nevada Test Site and Death Valley National Park. Aeromagnetic flight lines were oriented east-west, spaced 400 m (0.25 mi) apart, and flown at an altitude of 150 m (500 ft) above terrain, or as low as permitted by safety considerations. Characteristic magnetic anomalies occur over volcanic terranes, such as Yucca Mountain and the Greenwater Range, and over Proterozoic basement rocks, such as Bare Mountain and the Black Mountains. Linear magnetic anomalies caused by offsets of volcanic rocks permit detailed mapping of shallow faults in volcanic terranes. Of particular interest are subtle anomalies that overlie alluvial deposits at Devils Hole and Pahrump Valley. Alignments of springs along magnetic anomalies at these locales suggest that these anomalies are caused by faults that cut the alluvium, displace magnetic rocks at depth, and eventually influence ground-water flow. Linear magnetic anomalies over the Funeral Mountains appear to coincide with a prominent set of north-northeast-striking faults that cut the Precambrian Stirling Quartzite, rocks that are typically nonmagnetic. The position and orientation of these anomalies with respect to springs north of Furnace Creek suggest that the faults may act as conduits for the flow of water from the north into Death Valley, but the mineralogical cause of the anomalies is unknown.

  14. International Uranium Resources Evaluation Project (IUREP) national favourability studies: Belize (Former British Honduras)

    International Nuclear Information System (INIS)

    Belize is a well-forested area of 22,960 square kilometers. Its capital is Belmopan. The country is generally flat north of the capital city. The flat, swampy Caribbean Coast of Belize gradually ascends to the low peaks of the Maya and Cockscomb Mountains (elevation to 1,120 meters). The area south of the Maya Mountains is much more rugged than the area to the north. The country is drained by seventeen rivers, the chief ones being the Belize, Hondo, New, Sibun, Monkey and Moho. There is 'hurricane danger in the July-October period. Belize has reportedly been surveyed by Gamma Ray Spectrometer for phosphates which probably would have contained sufficient uranium to be detectable. The survey traversed about 1,000 line kms along major north-south and east-west roads as well as many secondary roads and trails. The uranium readings ranged from 0. to 9.9 ppm with a uranium content of 1-2 ppm in the limestone areas and 2-7 ppm in the alluvium-covered areas. The U/Th ratio varied from 0.11 to 1.65. A recent traverse across the Mountain Pine Ridge batholith gave one reading as high as 36 ppm but the average was about 9-10 ppm. The upper 1000-3000 feet of core and cuttings from nine deep oil wells were checked for phosphates and uranium. Most of the core and cuttings were almost pure limestones. The P203 content was less than 0.05 percent and no uranium was detected. It is very doubtful that any significant uranium occurrences will be found in the sediments surrounding the Maya Mountain uplift. However, there is a slight chance that uranium might occur in the granites and pegmatites in the Maya Mountains. The potential of Belize is estimated to be in the less than 1.000 tonnes uranium range, considering the restricted range, of geologic environments encountered there

  15. Hydrogeochemical and stream sediment detailed geochemical survey for Edgemont, South Dakota; Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Butz, T.R.; Dean, N.E.; Bard, C.S.; Helgerson, R.N.; Grimes, J.G.; Pritz, P.M.

    1980-05-31

    Results of the Edgemont detailed geochemical survey are reported. Field and laboratory data are presented for 109 groundwater and 419 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are given. A generalized geologic map of the survey area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. Groundwaters containing greater than or equal to 7.35 ppB uranium are present in scattered clusters throughout the area sampled. Most of these groundwaters are from wells drilled where the Inyan Kara Group is exposed at the surface. The exceptions are a group of samples in the northwestern part of the area sampled and south of the Dewey Terrace. These groundwaters are also produced from the Inyan Kara Group where it is overlain by the Graneros Group and alluvium. The high uranium groundwaters along and to the south of the terrace are characterized by high molybdenum, uranium/specific conductance, and uranium/sulfate values. Many of the groundwaters sampled along the outcrop of the Inyan Kara Group are near uranium mines. Groundwaters have high amounts of uranium and molybdenum. Samples taken downdip are sulfide waters with low values of uranium and high values of arsenic, molybdenum, selenium, and vanadium. Stream sediments containing greater than or equal to 5.50 ppM soluble uranium are concentrated in basins draining the Graneros and Inyan Kara Groups. These values are associated with high values for arsenic, selenium, and vanadium in samples from both groups. Anomalous values for these elements in the Graneros Group may be caused by bentonite beds contained in the rock units. As shown on the geochemical distribution plot, high uranium values that are located in the Inyan Kara Group are almost exclusively draining open-pit uranium mines.

  16. Hydrogeochemical and stream sediment detailed geochemical survey for Edgemont, South Dakota; Wyoming

    International Nuclear Information System (INIS)

    Results of the Edgemont detailed geochemical survey are reported. Field and laboratory data are presented for 109 groundwater and 419 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are given. A generalized geologic map of the survey area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. Groundwaters containing greater than or equal to 7.35 ppB uranium are present in scattered clusters throughout the area sampled. Most of these groundwaters are from wells drilled where the Inyan Kara Group is exposed at the surface. The exceptions are a group of samples in the northwestern part of the area sampled and south of the Dewey Terrace. These groundwaters are also produced from the Inyan Kara Group where it is overlain by the Graneros Group and alluvium. The high uranium groundwaters along and to the south of the terrace are characterized by high molybdenum, uranium/specific conductance, and uranium/sulfate values. Many of the groundwaters sampled along the outcrop of the Inyan Kara Group are near uranium mines. Groundwaters have high amounts of uranium and molybdenum. Samples taken downdip are sulfide waters with low values of uranium and high values of arsenic, molybdenum, selenium, and vanadium. Stream sediments containing greater than or equal to 5.50 ppM soluble uranium are concentrated in basins draining the Graneros and Inyan Kara Groups. These values are associated with high values for arsenic, selenium, and vanadium in samples from both groups. Anomalous values for these elements in the Graneros Group may be caused by bentonite beds contained in the rock units. As shown on the geochemical distribution plot, high uranium values that are located in the Inyan Kara Group are almost exclusively draining open-pit uranium mines

  17. The role of local soil-induced amplification in the 27 July 1980 northeastern Kentucky earthquake

    Science.gov (United States)

    Woolery, E.W.; Lin, T.-L.; Wang, Z.; Shi, B.

    2008-01-01

    Amplification of earthquake ground motions by near-surface soil deposits was believed to have occurred in Maysville, Kentucky, U.S.A. during the northeast Kentucky (Sharpsburg) earthquake (mb,Lg 5.3) of July 27, 1980. The city of Maysville, founded on approximately 30 m of Late Quaternary Ohio River flood plain alluvium, was 52 km from the epicenter, but experienced equivalent or higher Modified Mercalli Intensity (MMI) VII, compared with the epicentral area of the earthquake (i.e., MMI VI-VII). In this study, dynamic soil properties were obtained at 10 sites in Maysville using seismic P-wave and S-wave (SH-mode) refraction and reflection methods. Synthetically generated composite time histories and limited geotechnical information, along with the measured dynamic properties, were used to perform one-dimensional linear-equivalent amplification analyses. The results indicated the soils generated ground-motion amplification factors between 3.0 and 6.0 and at a frequency range between 2.0 and 5.0 Hz (0.2 to 0.5 s). The building damage in Maysville from the Sharpsburg earthquake was predominantly found in one- to three-story masonry structures. The estimated fundamental period for one- to three-story masonry buildings is approximately 0.11 to 0.26 s (3.8 to 9 Hz). These correlations suggest the elevated ground motion intensity in Maysville can be accounted for by near-surface soil-amplification effects and resonance of the ground motion by the buildings (i.e., double resonance).

  18. Nitrous oxide emission from cropland and adjacent riparian buffers in contrasting hydrogeomorphic settings.

    Science.gov (United States)

    Fisher, K; Jacinthe, P A; Vidon, P; Liu, X; Baker, M E

    2014-01-01

    Riparian buffers are important nitrate (NO) sinks in agricultural watersheds, but limited information is available regarding the intensity and control of nitrous oxide (NO) emission from these buffers. This study monitored (December 2009-May 2011) NO fluxes at two agricultural riparian buffers in the White River watershed in Indiana to assess the impact of land use and hydrogeomorphologic (HGM) attributes on emission. The study sites included a riparian forest in a glacial outwash/alluvium setting (White River [WR]) and a grassed riparian buffer in tile-drained till plains (Leary Weber Ditch [LWD]). Adjacent corn ( L.) fields were monitored for land use assessment. Analysis of variance identified season, land use (riparian buffer vs. crop field), and site geomorphology as major drivers of NO fluxes. Strong relationships between N mineralization and NO fluxes were found at both sites, but relationships with other nutrient cycling indicators (C/N ratio, dissolved organic C, microbial biomass C) were detected only at LWD. Nitrous oxide emission showed strong seasonal variability; the largest NO peaks occurred in late spring/early summer as a result of flooding at the WR riparian buffer (up to 27.8 mg NO-N m d) and N fertilizer application to crop fields. Annual NO emission (kg NO-N ha) was higher in the crop fields (WR: 7.82; LWD: 6.37) than in the riparian areas. A significant difference ( riparian buffers was detected (4.32 vs. 1.03 kg NO-N ha at WR and LWD, respectively), and this difference was attributed to site geomorphology and flooding (WR is flood prone; no flooding occurred at tile-drained LWD). The study results demonstrate the significance of landscape geomorphology and land-stream connection (i.e., flood potential) as drivers of NO emission in riparian buffers and therefore argue that an HGM-based approach should be especially suitable for determination of regional NO budget in riparian ecosystems. PMID:25602568

  19. Fluoride occurrence in the groundwater in a coastal region of Andhra Pradesh, India

    Science.gov (United States)

    Rao, N. Subba; Rao, P. Surya; Dinakar, A.; Rao, P. V. Nageswara; Marghade, Deepali

    2015-09-01

    Fluoride (F-) content varies from 0.60 to 1.80 mg/L in the coastal region between Chirala and Ongole of Andhra Pradesh, India. It exceeds the threshold limit of 1.20 mg/L in 20 % of the total groundwater samples. The aim of the present study is to assess the controlling factors of F- content. The study area experiences a dry climate and is underlain by Charnockite Group of rocks over which the river and coastal alluvium occur. The results of the study identify the four factors that control the high F- content. First one is related to alkalinity, leading to active dissolution and leaching of F--bearing minerals, which supports the positive correlation of F- with pH and HCO3 -. A longer water residence time in the clays is the second factor, which activates not only solubility and dissolution of F--bearing minerals, but also anion exchange between F- and OH-. Third factor is a result of higher Na+ due to impact of saline water, ion exchange between Na+ and Ca2+, and precipitation of CaCO3. This reduces the Ca2+ content, causing dissolution of CaF2 to maintain the chemical equilibria, which is supported by positive correlation between Na2+ and F-. The influence of anthropogenic activities is the last factor, which acts as an additional source of F-. Thus, the shallow groundwater shows higher content of F- and the hydrogeochemical facies also support this hypothesis. The study suggests the remedial measures to reduce the F- content.

  20. A sedimentary model for early Palaeozoic fluvial fans, Alderney Sandstone Formation (Channel Islands, UK)

    Science.gov (United States)

    Ielpi, Alessandro; Ghinassi, Massimiliano

    2016-08-01

    Fluvial fans in the rock record are inferred based on critical criteria such as: downstream grain-size fining; evidence for drainage fractionation along bifurcating channels; increasing fluvial-aeolian interaction in the basinward direction; and radial palaeoflow dispersion. Since pre-vegetation fluvial rocks often lack heterolithic alluvium and channelisation at the outcrop scale, the recognition of pre-Silurian fluvial fans has, so far, not been straightforward. This research proposes a sedimentary model for the Alderney Sandstone Formation of Channel Islands (UK), so far considered as a fine record of early Palaeozoic axial-fluvial sedimentation. Here, outcrop-based and remote-sensing analysis of the formation's type-section reveal the interaction of fluvial and aeolian processes, expressed by the alternation of: compound fluvial bars enclosing macroform surfaces, related to phases of perennial discharge; fluvial sandsheets containing antidunal forms and soft-sediment deformations, related to seasonal (i.e. flashy) discharge; and aeolian bedforms overlying thin stream-flow deposits. An up-section increase in aeolian deposits is accompanied by the shrinking of fluvial bars and minor-channel cuts, suggesting that drainage was fractioned along smaller channels terminating into marginal aeolian environments. Together with a propensity towards more dispersed values of fluvial cross-set thickness up-section (again due to discharge fractionation along intermittently active channels), these features depict an aeolian-influenced fluvial fan. This work discusses a set of criteria for the identification of fluvial fans in pre-vegetation environments. In doing so, it also explores possible parallels to modern environments, and underscores the potential of integrated outcrop and remotely sensed observations on ancient fluvial rocks and modern sedimentary realms.

  1. Hydrologic characteristics of the Agua Fria National Monument, central Arizona, determined from the reconnaissance study

    Science.gov (United States)

    Fleming, John B.

    2005-01-01

    Hydrologic conditions in the newly created Agua Fria National Monument were characterized on the basis of existing hydrologic and geologic information, and streamflow data collected in May 2002. The study results are intended to support the Bureau of Land Management's future water-resource management responsibilities, including quantification of a Federal reserved water right within the monument. This report presents the study results, identifies data deficiencies, and describes specific approaches for consideration in future studies. Within the Agua Fria National Monument, the Agua Fria River flows generally from north to south, traversing almost the entire 23-mile length of the monument. Streamflow has been measured continuously at a site near the northern boundary of the monument since 1940. Streamflow statistics for this site, and streamflow measurements from other sites along the Agua Fria River, indicate that the river is perennial in the northern part of the monument but generally is intermittent in downstream reaches. The principal controls on streamflow along the river within the monument appear to be geology, the occurrence and distribution of alluvium, inflow at the northern boundary and from tributary canyons, precipitation, and evapotranspiration. At present, (2004) there is no consistent surface-water quality monitoring program being implemented for the monument. Ground-water recharge within the monument likely results from surface-water losses and direct infiltration of precipitation. Wells are most numerous in the Cordes Junction and Black Canyon City areas. Only eight wells are within the monument. Ground-water quality data for wells in the monument area consist of specific-conductance values and fluoride concentrations. During the study, ground-water quality data were available for only one well within the monument. No ground-water monitoring program is currently in place for the monument or surrounding areas.

  2. Geothermal Exploration in Hot Springs, Montana

    Energy Technology Data Exchange (ETDEWEB)

    Toby McIntosh, Jackola Engineering

    2012-09-26

    The project involves drilling deeper in the Camp Aqua well dri lled in June 1982 as part of an effort to develop an ethanol plant. The purpose of the current drill ing effort is to determine if water at or above 165°F exists for the use in low temperature resource power generation. Previous geothermal resource study efforts in and around Hot Springs , MT and the Camp Aqua area (NE of Hot Springs) have been conducted through the years. A confined gravel aquifer exists in deep alluvium overlain by approximately 250 of si lt and c lay deposits from Glacial Lake Missoula. This gravel aquifer overlies a deeper bedrock aquifer. In the Camp Aqua area several wel l s exist in the gravel aquifer which receives hot water f rom bedrock fractures beneath the area. Prior to this exploration, one known well in the Camp Aqua area penetrated into the bedrock without success in intersecting fractures transporting hot geothermal water. The exploration associated with this project adds to the physical knowledge database of the Camp Aqua area. The dri l l ing effort provides additional subsurface information that can be used to gain a better understanding of the bedrock formation that i s leaking hot geothermal water into an otherwise cold water aquifer. The exi s t ing well used for the explorat ion is located within the center of the hottest water within the gravel aquifer. This lent i t sel f as a logical and economical location to continue the exploration within the existing well. Faced with budget constraints due to unanticipated costs, changing dril l ing techniques stretched the limited project resources to maximize the overa l l well depth which f e l l short of original project goals. The project goal of finding 165°F or hotter water was not achieved; however the project provides additional information and understanding of the Camp Aqua area that could prove valuable in future exploration efforts

  3. Prehistoric horticultural adaptation of soils in the middle Waikato Basin : review and evidence from S14/201 and S14/185, Hamilton

    International Nuclear Information System (INIS)

    The middle Waikato Basin contains extensive evidence, reviewed here, for the modification of soils for horticulture (gardening) by pre-European Maori. We investigated an area of Maori gardens at archaeological sites S14/201 and S14/185 in Hamilton City. Two groups of multiple, near-circular hollows, each about 0.3 m in diameter and infilled with gravelly sand, were exposed during the site excavations. The hollows, extending through modified A horizon materials into upper B horizon materials, are interpreted as representing the lower part of small truncated mounds (puke) that had been built up by early Maori for growing kumara (Ipomoea batatas). The hollows were grouped in a distinctive quincunx-like pattern in which four hollows formed the corners of a square with one hollow in the centre. The characteristics and layout of the hollows match historical descriptions of mounds used by Maori gardeners. We also used particle-sized analysis to quantify the extent to which upper horizons of the antedecent soils had been modified by the addition of gravel and sand excavated from borrow pits in adjacent volcanogenic alluvium (Hinuera Formation). A radiocarbon date obtained from charcoal found in a fireplace under the modified A horizon and near the hollows suggests that the site was occupied in the late fifteenth century. Identification to species level of charcoal fragments found in the modified soil suggests that site S14/201 may have been cleared of large podocarp trees not long before gardening activities began. This conclusion is supported by similar evidence from another site on the same stretch of the Waikato River. If so, such late (localised) deforestation contrasts with evidence from other palaeoenvironmental studies that shows regional deforestation began considerably earlier (about AD 1300) in the Waikato region. (author). 63 refs., 9 figs., 7 tabs

  4. Geologic map of the Oasis Valley basin and vicinity, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Fridrich, C.J.; Minor, S.A.; Ryder, P.L.; Slate, J.L.

    2000-01-13

    This map and accompanying cross sections present an updated synthesis of the geologic framework of the Oasis Valley area, a major groundwater discharge site located about 15 km west of the Nevada Test Site. Most of the data presented in this compilation is new geologic map data, as discussed below. In addition, the cross sections incorporate new geophysical data that have become available in the last three years (Grauch and others, 1997; written comm., 1999; Hildenbrand and others, 1999; Mankinen and others, 1999). Geophysical data are used to estimate the thickness of the Tertiary volcanic and sedimentary rocks on the cross sections, and to identify major concealed structures. Large contiguous parts of the map area are covered either by alluvium or by volcanic units deposited after development of the major structures present at the depth of the water table and below. Hence, geophysical data provide critical constraints on our geologic interpretations. A companion paper by Fridrich and others (1999) and the above-cited reports by Hildenbrand and others (1999) and Mankinen and others (1999) provide explanations of the interpretations that are presented graphically on this map. This map covers nine 7.5-minute quadrangles in Nye County, Nevada, centered on the Thirsty Canyon SW quadrangle, and is a compilation of one published quadrangle map (O'Connor and others, 1966) and eight new quadrangle maps, two of which have been previously released (Minor and others, 1997; 1998). The cross sections that accompany this map were drawn to a depth of about 5 km below land surface at the request of hydrologists who are modeling the Death Valley groundwater system.

  5. Effects of the earthquake of March 27, 1964, at Seward, Alaska: Chapter E in The Alaska earthquake, March 27, 1964: effects on communities

    Science.gov (United States)

    Lemke, Richard W.

    1967-01-01

    area, where the rocks consist almost entirely of graywacke and phyllite, is from near north to N. 20° E. Beds and cleavage of the rocks commonly dip 70° W. or NW. to near vertical. Locally, the rocks are complexly folded or contorted. So major faults were found in the mapped area, but small faults, shear zones, and joints are common. Surficial deposits of the area hare been divided for mapping into the following units: drift deposits, alluvial fan deposits, valley alluvium, intertidal deposits, landslide deposits, and artificial fill. Most of these units intergrade and were deposited more or less contemporaneously. The drift deposits consist chiefly of till that forms moraines along the lower flanks of the Resurrection River valley and up tributary valleys. The till is predominantly silt and sand and lesser amounts of clay-size particles, gravel, cobbles, and boulders. Glacial outwash and stratified ice-contact deposits constitute the remainder of the drift deposits. Fans and fan-deltas have been deposited at the valley mouths of tributary streams. Some, including the one upon which Seward built, project into Resurrection Bay, and deltaic-type deposits form their distal edges. The larger fans—composed chiefly of loosely compacted and poorly sorted silt, sand, and gravel—form broad aprons having low gradients. The fan deposits range in thickness from about 100 feet to possibly several hundred feet and, at least in some places, lie on a platform of compact drift. Smaller fans at the mouths of several canyons have steep gradients and considerable local relief. Valley alluvium, deposited chiefly by the Resurrection River, consists mostly of coarse sand and fine to medium gravel. In the axial part of the valley it is probably more than 100 feet thick. Near the head of Resurrection Bay, the alluvium is underlain by at least 75 feet of marine deltaic sediments, which are in turn underlain by 600 or more feet of drift in the deepest part of the bedrock valley. Beach

  6. Ground-water resources of the Lambayeque Valley, Department of Lambayeque, northern Peru

    Science.gov (United States)

    Schoff, Stuart L.; Sayan, M. Juan Luis

    1969-01-01

    Ground water in the Lambayeque Valley has been developed mainly for irrigation of sugarcane and rice. The locality is on the coastal plain of northern Peru, about 650 km (kilometers) northwest of Lima, the national capital. The area considered in this study is about 1,670 sq km (square kilometers) and is mainly on the alluvial fan of Rio Chancay and entirely in the Department of Lambayeque. Chiclayo, the departmental capital and largest city, has a population, of about 46,000. The climate is hot and virtually rainless. Agriculture is dependent on irrigation. The available water, whether in stream s or underground, is introduced from the Andean highlands by Rio Chancay. Rocks in the area range in age from Cretaceous, or possibly Jurassic, to Quaternary and in lithology from dense and hard igneous, sedimentary, and metamorphic rocks to unconsolidated sediments. The bedrock contains and yields water only in small quantities, if at all. The principal water-bearing strata are in the alluvium comprising the fan of Rio Chancay. Where ground water in the alluvium has been most intensively developed, the productive zone is within 20 m (meters) of the land surface and is composed approximately as follows: (1) relatively impermeable soil, clay, and clayey sand, 5 to 10 m thick, (2) permeable sand and gravel, 6 to 10 m thick, at places including one or more layers of clay, so that several water-bearing beds are distinguishable, and (3) relatively impermeable mixtures of clay, sand, and gravel extending below the bottom of wells. Unit 3 in the deepest test continued to 102 m. Unit 2 is the principal source of water tapped by irrigation wells. In the northern part of the area wells locally yield water rather freely from strata as deep as 73 m, but elsewhere in the area the strata deeper than 20 m are not very productive. Wells at and near Chiclayo yield only small amounts, and the deepest well disclosed, in 100 m of material, only 5.5 m of material that can be considered as

  7. Description and analysis of the geohydrologic system in western Pinal County, Arizona

    Science.gov (United States)

    Hardt, W.F.; Cattany, R.E.

    1965-01-01

    Western Pinal County is between Phoenix and Tucson in the Basin and Range physiographic province of southern Arizona and consists of about 2,000 square miles of valley floor with low relief surrounded by mountains. It is the second largest agricultural area in the State, and about 25 percent of the ground water pumped in the State is from this area. The study area has been divided into four parts. Three of these--the Casa Grande-Florence area, the Eloy area, and the Stanfield-Maricopa area--are in the lower Santa Cruz basin; the fourth--the Gila River area--is a long narrow strip along the Gila River from the Ashurst-Hayden Dam to the confluence of the Gila and Santa Cruz Rivers. The project was undertaken to provide a better understanding of the ground-water supply in relation to the present and potential water use in this area of extensive ground-water development. The arid climate of western Pinal County--combining high temperatures and low humidity--causes most of the precipitation to be returned to the atmosphere by evapotranspiration, which leaves only a very small part for recharge to the ground-water reservoir. The computed potential evapotranspiration--44. 97 inches--is five times greater than the average precipitation. In general, the subsurface materials in western Pinal County are unconsolidated alluvial deposits underlain by consolidated alluvium and crystalline rocks and bounded by mountains consisting of crystalline and minor sedimentary rocks. The crystalline and sedimentary rocks of the mountains are not known to be water bearing in western Pinal County. The impermeable rocks underlying the basin are called the hydrologic bedrock unit in this report. Although the unit may consist of several different rock types, the distinction between them is relatively unimportant in this study because none of them yield appreciable amounts of water. The lower Santa Cruz basin in western Pinal County is divided into two sections by a buried ridge of the

  8. Geologic framework, age, and lithologic characteristics of the North Park Formation in North Park, north-central Colorado

    Science.gov (United States)

    Shroba, Ralph R.

    2016-10-18

    Deposits of the North Park Formation of late Oligocene and Miocene age are locally exposed at small, widely spaced outcrops along the margins of the roughly northwest-trending North Park syncline in the southern part of North Park, a large intermontane topographic basin in Jackson County in north-central Colorado. These outcrops suggest that rocks and sediments of the North Park Formation consist chiefly of poorly consolidated sand, weakly cemented sandstone, and pebbly sandstone; subordinate amounts of pebble conglomerate; minor amounts of cobbly pebble gravel, siltstone, and sandy limestone; and rare beds of cobble conglomerate and altered tuff. These deposits partly filled North Park as well as a few small nearby valleys and half grabens. In North Park, deposits of the North Park Formation probably once formed a broad and relatively thick sedimentary apron composed chiefly of alluvial slope deposits (mostly sheetwash and stream-channel alluvium) that extended, over a distance of at least 150 kilometers (km), northwestward from the Never Summer Mountains and northward from the Rabbit Ears Range across North Park and extended farther northwestward into the valley of the North Platte River slightly north of the Colorado-Wyoming border. The maximum preserved thickness of the formation in North Park is about 550 meters near the southeastern end of the North Park syncline.The deposition of the North Park Formation was coeval in part with local volcanism, extensional faulting, development of half grabens, and deposition of the Browns Park Formation and Troublesome Formation and was accompanied by post-Laramide regional epeirogenic uplift. Regional deposition of extensive eolian sand sheets and loess deposits, coeval with the deposition of the North Park Formation, suggests that semiarid climatic conditions prevailed during the deposition of the North Park Formation during the late Oligocene and Miocene.The North Park Formation locally contains a 28.1-mega-annum (Ma

  9. Arid Climate Landscape Evolution and the Pediment Problem

    Science.gov (United States)

    Strudley, M. W.; Murray, A. B.; Haff, P. K.

    2003-12-01

    Although widely disseminated throughout many different climatic environments, pediments, or gently sloping, laterally extensive surfaces characterized by a thin veneer of alluvium covering bedrock, are particularly well developed in granitic desert locales such as the Mojave and Colorado Deserts in southern California and the Sonoran Desert in western Arizona. These features form a transitional zone within the piedmont of many exposed batholithic mountainous bodies, separating a zone of bare bedrock erosion in the steep mountain mass from a depositional zone in the alluvial basin. Well developed pediments in granitic environments commonly contain bedrock outcroppings (tors or inselbergs) that may remain uncovered indefinitely and sharp slope discontinuities at the piedmont junction separating the pediment surface from the mountain mass. Pediments have been the focus of debate in geomorphic circles for over half a century. While some geomorphologists have proposed that pediments and their associated tor fields represent unearthed relict landforms, others propose unique modes of sediment transport that form and maintain the beveled form of pediment surfaces. We hypothesize that a simple relationship between bedrock weathering and alluvial thickness could explain this range of enigmatic features and phenomena, a relationship that Anderson (2002) incorporates in his proposed explanation for high alpine surfaces and tors. Field observations suggest that the transformation of bedrock to regolith is most rapid with a finite covering of regolith. This weathering rule, combined with a simple set of sediment transport rules provides a mechanism through which pediment surfaces are produced. We examine the development of pediment surfaces and associated features using a 3D numerical, distributed-parameter landscape evolution model incorporating the most pertinent landscape development processes acting in arid regions. Temporally and spatially variable rainfall (storm size

  10. Effects of Topography and Soil Depth on Runon and Focused Infiltration: Upper Split Wash Watershed, Nevada

    Science.gov (United States)

    Woolhiser, D. A.; Fedors, R. W.; Stothoff, S. A.

    2001-12-01

    A modeling study of surface and near surface hydrology of a small watershed, upper Split Wash, overlying the potential Yucca Mountain (YM), Nevada high level nuclear waste repository was carried out. The objective was to evaluate the interaction of topography and soil depth across a small watershed and the hillslope process of runoff-runon. Zones of focused infiltration can result from the phenomenon of runon leading to localized deep percolation. The distribution of percolation fluxes within YM has a significant impact on repository performance. The KINEROS2 surface runoff model was used to calculate distributed Hortonian and saturation-induced overland flow using 9-years of tipping bucket precipitation data and 100-years of simulated precipitation. In the KINEROS2 model, watershed geometry is described by cascades of plane elements contributing lateral or upper boundary flow to trapezoidal channel elements. The Smith-Parlange model is used for infiltration and saturated and unsaturated flow were assumed to be in the vertical direction. Plane and channel geometries for the Upper Split Wash watershed (0.25 km2), were determined from topographic maps and field measurements. Soil depths, soil and bedrock hydraulic parameters, initial water contents, and Mannings "n" for plane and channels were based on a combination of field measurements and values reported in the literature. Runoff was simulated for all storms that had intensities greater than the saturated hydraulic conductivity of the soil or had a total depth that could saturate the shallowest soils. Simulated runoff per unit area for the measured precipitation compared reasonably well with measurements at nearby watersheds. For the upper Split Wash watershed, the runoff-runon phenomenon was important during the infrequent saturation-induced overland flow events but was not important for Hortonian runoff. Focused infiltration into channel alluvium and underlying bedrock occurred for both types of runoff

  11. Interpretation of a 3D Seismic-Reflection Volume in the Basin and Range, Hawthorne, Nevada

    Science.gov (United States)

    Louie, J. N.; Kell, A. M.; Pullammanappallil, S.; Oldow, J. S.; Sabin, A.; Lazaro, M.

    2009-12-01

    A collaborative effort by the Great Basin Center for Geothermal Energy at the University of Nevada, Reno, and Optim Inc. of Reno has interpreted a 3d seismic data set recorded by the U.S. Navy Geothermal Programs Office (GPO) at the Hawthorne Army Depot, Nevada. The 3d survey incorporated about 20 NNW-striking lines covering an area of approximately 3 by 10 km. The survey covered an alluvial area below the eastern flank of the Wassuk Range. In the reflection volume the most prominent events are interpreted to be the base of Quaternary alluvium, the Quaternary Wassuk Range-front normal fault zone, and sequences of intercalated Tertiary volcanic flows and sediments. Such a data set is rare in the Basin and Range. Our interpretation reveals structural and stratigraphic details that form a basis for rapid development of the geothermal-energy resources underlying the Depot. We interpret a map of the time-elevation of the Wassuk Range fault and its associated splays and basin-ward step faults. The range-front fault is the deepest, and its isochron map provides essentially a map of "economic basement" under the prospect area. There are three faults that are the most readily picked through vertical sections. The fault reflections show an uncertainty in the time-depth that we can interpret for them of 50 to 200 ms, due to the over-migrated appearance of the processing contractor’s prestack time-migrated data set. Proper assessment of velocities for mitigating the migration artifacts through prestack depth migration is not possible from this data set alone, as the offsets are not long enough for sufficiently deep velocity tomography. The three faults we interpreted appear as gradients in potential-field maps. In addition, the southern boundary of a major Tertiary graben may be seen within the volume as the northward termination of the strong reflections from older Tertiary volcanics. Using a transparent volume view across the survey gives a view of the volcanics in full

  12. Fluvial process and morphology of the Brahmaputra River in Assam, India

    Science.gov (United States)

    Sarma, J. N.

    2005-09-01

    The Brahmaputra River finds its origin in the Chema Yundung glacier of Tibet and flows through India and Bangladesh. The slope of the river decreases suddenly in front of the Himalayas and results in the deposition of sediment and a braided channel pattern. It flows through Assam, India, along a valley comprising its own Recent alluvium. In Assam the basin receives 300 cm mean annual rainfall, 66-85% of which occurs in the monsoon period from June through September. Mean annual discharge at Pandu for 1955-1990 is 16,682.24 m 3 s - 1. Average monthly discharge is highest in July (19%) and lowest in February (2%). Most hydrographs exhibit multiple flood peaks occurring at different times from June to September. The mean annual suspended sediment load is 402 million tons and average monthly sediment discharge is highest in June (19.05%) and lowest in January (1.02%). The bed load at Pandu was found to be 5-15% of the total load of the river. Three kinds of major geomorphic units are found in the basin. The river bed of the Brahmaputra shows four topographic levels, with increasing height and vegetation. The single first order primary channels of this braided river split into two or more smaller second order channels separated by bars and islands. The second order channels are of three kinds. The maximum length and width of the bars in the area under study are 18.43 km and 6.17 km, respectively. The Brahmaputra channel is characterised by mid-channel bars, side bars, tributary mouth bars and unit bars. The geometry of meandering tributary rivers shows that the relationship between meander wavelength and bend radius is most linear. The Brahmaputra had been undergoing overall aggradation by about 16 cm during 1971 to 1979. The channel of the Brahmaputra River has been migrating because of channel widening and avulsion. The meandering tributaries change because of neck cut-off and progressive shifting at the meander bends. The braiding index of the Brahmaputra has been

  13. Aerogammaspectrometric anomalies (K, eU and eTh) from Araras region (SP) and its relations with pedogenetic processes and phosphate fertilizers; Anomalias aerogamaespectrometricas (K, eU e eTh) da quadricula de Araras (SP) e suas relacoes com processos pedogeneticos e fertilizantes fosfatos

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Jocelyn Lopes de; Ferreira, Francisco Jose Fonseca, E-mail: jocelyn_informatica@yahoo.com.br, E-mail: jocelyn.souza@utp.br, E-mail: francisco.ferreira@ufpr.br [Universidade Federal do Parana (LPGA/UFPR), Curitiba, PR (Brazil). Dept. de Geologia. Lab. de Pesquisas em Geofisica Aplicada

    2005-07-15

    Radionuclides are present in the raw materials utilized in the manufacturing of some fertilizers and, consequently, the redistribution of uranium, thorium and potassium by agricultural activities may lead to the contamination of intensively fertilized soils. Airborne gamma-ray data on K, eU and Th have shown the coincidence of aerogammaspectrometric anomalies and diabase sills in the Araras region (SP). This area is situated between the coordinates latitude 22 deg 00'/22 deg 30' South and longitude 47 deg 00' and 47 deg 30' West. As the contents of radionuclides in basic rocks are low and aerial gamma-ray surveys reveal gamma radiation from the 30 cm of the soil profile (coinciding with topsoil), interest has been raised to investigate which soils are included in the anomalies reported, as well as what sort of agricultural activity is carried out, in order to attest whether the source of radioactivity originated from the chemical fertilizers applied, thus establishing the main purpose of the present research. Integration by GIS has revealed that (1) eU and eTh anomalies occur on latossolos roxos massively fertilized with phosphates, on the level and elevated parts of the terrain; (2) high levels of uranium are associated with clay particle size in regoliths developed on diabase sills; (3) potassium and thorium anomalies follow Quaternary alluviums which extend along the banks of the Moji river, the occurrence of anomalous K accounting for the presence of feldspars in the included soils, and the occurrence of eTh related to local fertilization and to the transport of clays and iron oxides from the uppermost parts of the terrain, where the Latossolos Roxos under sugarcane are located. Radiochemical analyses of U and Th in fertilizers were in agreement with the literature, and it has been observed the influence of the geological genesis of the source of the raw material utilized in the production of the fertilizer, as well as the increase in

  14. Near-Channel Sources and Sinks along a Mountainous Stream: Establishing the Controls and Time Scales of the Lateral Transfer of Sediment and Carbon

    Science.gov (United States)

    Gartner, J. D.; Renshaw, C. E.

    2015-12-01

    River channels exchange sediment, carbon, and other matter with hillslopes and floodplains. An ongoing challenge is to quantify the time and length scales of these lateral interactions, and to establish physical controls on direction of transfer. Here we investigate whether downstream changes in stream power (Ω) can predict near-channel sources or sinks of matter on decadal time scales in a case study of Mink Brook, a 50 km2 watershed in New Hampshire, USA. Building on the Exner equation, we hypothesize that reaches with downstream increases in stream power (Ω↑) exhibit near-channel deposition and accumulation of organic matter, and reaches of downstream decreases in stream power (Ω↓) exhibit near-channel erosion and stripping of organic matter. We measured 210Pbex inventory (an indicator of erosion versus deposition), organic matter inventory, grain size, and depth of alluvium/colluvium in 29 soil pits at 6 cross sections along the brook. Sites had equivalent total Ω for a given storm event. However, 3 cross sections exhibited Ω↑, and 3 exhibited Ω↓. All cross sections showed a general trend of stripping of organic matter and fine sediment particles in the channel, paired with loading of matter at the ~2-year flood elevation. From the ~2- to ~25-year flood elevation, a marked difference appeared between sites. The Ω↑ cross sections exhibited several locations of erosion and stripping of organic matter, as evidenced by low 210Pbex inventories (70 to 1,000 bq m-2), low organic matter inventories (17 to 219 kg m-2), and thin alluvial cover (average 23 cm). The low 210Pbex inventories, below the characteristic 6,000 bq m-2 of stable soil profiles in this region, suggest no areas had consistent deposition over the last century. In contrast, the Ω↓ cross sections exhibited deposition of fine particles and organic matter from the ~2- to ~25-year flood elevation, as evidenced by elevated 210Pbex inventories (up to 9,100 bq m-2), elevated organic matter

  15. A New Quaternary Strand of the Karakoram Fault System, Ladakh Himalayas

    Science.gov (United States)

    Bohon, W.; Hodges, K.; Arrowsmith, R.; Tripathy, A.

    2009-12-01

    The NW-SE striking, dextral Karakoram fault system stretches for more than 1200 km from the Pamirs of Central Asia at least as far southeast as the Kailas area of Tibet. Estimates for the total lateral displacement along the fault system range from 150-1000 km, and estimated Quaternary rates of slip range from 1 to 30 mm/yr. In the Ladakh region of NW India (~ 33°28’N, 78°45’E), the fault system expresses as northern and southern strands bounding the Pangong Range. Studies of ductile deformation fabrics along these strands suggest that slip began in the Miocene, and Brown et al. (2002) documented Quaternary right-lateral slip along the northern strand at ~4 mm/yr on the basis of offset geomorphic features. The lack of documented Quaternary offset along the southern strand has led most researchers to assume that Quaternary slip on the Karakoram fault system in this region was partitioned exclusively to the northern strand. Our summer 2009 field work in the Pangong Range and adjacent Nubra Valley provides the first documentation of significant Quaternary activity along the southern strand. In the valley between the villages of Tangste (34°01’ N, 78°10’ E) and Durbuk (34°06’ N, 78°07’), the fault is visible high on the northeastern mountain side as a break in slope with offset Quaternary paleosurfaces and beheaded and offset stream channels, the largest of which have been displaced by as much as 250 m. Field mapping north of Durbuk, near the town of Tangyar (34°15’N, 77°52’E), shows that the southern strand continues northwest and cuts across the landscape as a sinuous, continuous trace with shutter ridges, offset alluvial fan surfaces, and sag ponds developed along its length. In this region, the northern and southern strands are linked by a Quaternary, E-directed thrust fault that places high-grade metamorphic rocks over poorly consolidated Quaternary alluvium. The partitioning of dextral slip between two strands of the Karakoram system

  16. HYROGEOLOGIC CHARACTERIZATION OF THE U-3at COLLAPSE ZONE

    Energy Technology Data Exchange (ETDEWEB)

    BECHTEL NEVADA

    2005-08-01

    Hydrogeologic characteristics and properties of the U-3at collapse zone were determined from cores obtained from two angled boreholes drilled in 1996 under the subsidence crater formed by an underground nuclear test in 1963. This crater, used for disposal of bulk low-level radioactive waste since 1988, is located within the Area 3 Radioactive Waste Management Site in Yucca Flat on the Nevada Test Site in Nye County, Nevada. The purpose of this characterization effort was to provide data required to develop a conceptual hydrogeologic model and to complete flow and transport modeling required for the Area 3 performance assessment and composite analysis. To minimize disturbance of the core samples, drilling was done by a method that used only air as the drilling fluid. No evidence of preferential pathways for water flow was detected via visual geologic descriptions of the core samples. Laboratory analyses showed physical and hydraulic properties that are typical of alluvial valleys at the Nevada Test Site. Water content values ranged from 0.05 to 0.33 cubic meters per cubic meter, with water content tending to increase with depth. Water potential values ranged from -10.7 MegaPascals at a depth of 15.3 meters to greater than -0.40 MegaPascals at 78.9 meters. Tritium concentrations in pore water extracted from the cores were below the detection limits from the surface to a depth of 118.9 meters. Below this depth, concentrations generally increased to a maximum of 2,200 picoCuries per liter in the deepest sample at 146.9 meters. Unusually wet alluvium recovered from the drill bit during drilling between 50.9 and 71.6 meters in the first borehole raised concerns that water condensed in the compressed air system or excess oil introduced into the borehole may have penetrated core segments intended for analyses. The drilling process was modified to preclude introduction of fluids and the borehole was completed without further evidence of excess water. Using the same drilling

  17. Seismic Characterization of the Jakarta Basin

    Science.gov (United States)

    Cipta, A.; Saygin, E.; Cummins, P. R.; Masturyono, M.; Rudyanto, A.; Irsyam, M.

    2015-12-01

    Jakarta, Indonesia, is home to more than 10 million people. Many of these people live in seismically non-resilient structures in an area that historical records suggest is prone to earthquake shaking. The city lies in a sedimentary basin composed of Quaternary alluvium that experiences rapid subsidence (26 cm/year) due to groundwater extraction. Forecasts of how much subsidence may occur in the future are dependent on the thickness of the basin. However, basin geometry and sediment thickness are poorly known. In term of seismic hazard, thick loose sediment can lead to high amplification of seismic waves, of the kind that led to widespread damage in Mexico city during the Michoacan Earthquake of 1985. In order to characterize basin structure, a temporary seismograph deployment was undertaken in Jakarta in Oct 2013- Jan 2014. A total of 96 seismic instrument were deployed throughout Jakarta were deployed throughout Jakarta at 3-5 km spacing. Ambient noise tomography was applied to obtain models of the subsurface velocity structure. Important key, low velocity anomalies at short period (<8s) correspond to the main sedimentary sub-basins thought to be present based on geological interpretations of shallow stratigraphy in the Jakarta Basin. The result shows that at a depth of 300 m, shear-wave velocity in the northern part (600 m/s) of the basin is lower than that in the southern part. The most prominent low velocity structure appears in the northwest of the basin, down to a depth of 800 m, with velocity as low as 1200 m/s. This very low velocity indicates the thickness of sediment and the variability of basin geometry. Waveform computation using SPECFEM2D shows that amplification due to basin geometry occurs at the basin edge and the thick sediment leads to amplification at the basin center. Computation also shows the longer shaking duration occurrs at the basin edge and center of the basin. The nest step will be validating the basin model using earthquake events

  18. Impact of Landslide Dams on River Profile Evolution

    Science.gov (United States)

    Safran, E. B.; Peden, D.; Harrity, K.; Anderson, S. W.; O'Connor, J. E.; Wallick, R.; House, P. K.; Ely, L.

    2008-12-01

    Large landslides that form channel blockages have the potential to inhibit or enhance local channel incision. Inhibitive effects include mantling of the channel bed with large caliber debris at the landslide site and with alluvium accumulated upstream of the blockage site. Incision enhancement downstream of the blockage site may result from catastrophic dam breach floods, with peak discharges potentially many times greater than those of meteorologically generated floods. Here, we use a 1-D finite difference model of longitudinal profile evolution to explore the implications of such processes for long-term (106 yr) incision patterns and morphologic development. We use simple rules to represent blockage-related perturbations to the rate of "background incision," which is driven by excess shear stress or stream power. The recurrence interval of landslides and the height of blockages are loosely constrained by field data from central and eastern Oregon. Scenarios simulated include a random spatial distribution of landslides; spatial clustering of landslides; temporal clustering of landslides; and variable rates of base-level lowering combined with landsliding. Spatial clustering of landslides in the downstream reaches of the evolving profile, such as we document in parts of central and eastern Oregon, has the greatest effect on local incision rate and long- wavelength profile morphology, reducing long-term incision rates by up to 50% in the most affected reaches and creating convexities in the channel profile with amplitudes of 100s of meters. These effects are amplified when coupled with rapid base level fall. Randomly distributed landslides slightly increase the overall convexity of the channel profile and create knickpoints that persist even after complete erosion of the blockages and associated aggradational wedges. In contrast, spatial clustering of landslides in the upper reaches of the profile, temporal clustering of landsliding, and landsliding coupled with

  19. STRATIGRAPHY AND STURUCTURAL EVOLUTION OF PONTID/ANATOLID SUTURE ZONE IN NE ANATOLIA (BETWEEN OLTU-NARMAN

    Directory of Open Access Journals (Sweden)

    Cevdet BOZKUŞ

    1998-01-01

    Full Text Available The rock units formed in Late Cretaceous to recent, outcrop in the investigated area. The oldest rock unit of the suture zone is a flysch (Alıcık formatıon of Upper Cretaceous (Santonıan-Maastrichtıan age containing volcanic intercalations. Ophiolitic melange tectonically set on the flysch. The initial emplacement of the ophioli- tic melange sheets in this area occur between Late Cretaceous and pre early Eocene. Lower-Midlle Eocene aged, fine grained continental to shallow marine sediments (Dağdibi formatıon cover all the units with an angular unconformity. On these sediments, Upper Eocene basic (basalt, basaltic andesite, tuff volcanics (Karataş formatıon are observed. Oligocene aged continental molasse sediments (Narman group which lie on the older units with an angular unconformity are; continental clastics, volcanic products and gypsum at the top displaying a thinning and fining upward motif of sequence. Pliocene-Pleistocene aged conglomerates represent river environments, cover all the units with an angular unconformity. Recent deposits are slope debris and alluvium. All the rocks exposed in the investigated area which take place Pontid /Anatolid suture zone and developed under the control of collisional tectonic processes of these two continents. In Upper Cretaceous age, the flysch is formed in a trench developed along a nortward dipping subductıon zone.. Ophiolitic melange which limits the suture zone at the south, is formed by slicing of oceanic crust and mixing of these slices with trench sediments by means of a tectono-sedimentary system.The collosion of Pontid/Anatolid continents (happened after Late Cretaceous and before Early Eocene. Lower-Mıddle Eocene (Ipresian-Lutetian aged continental, to shallow marine deposits were formed in an asimetric forearc molassic basin which developed along the suture zone. Oligocene aged continental deposits were developed together with volcanics in continental intermountain molassic

  20. Resistivity Imaging of Spring Valley, Nevada Using the Audiomagnetotelluric Method

    Science.gov (United States)

    McPhee, D. K.; Pellerin, L.; Chuchel, B.; Dixon, G. L.

    2005-05-01

    Audiomagnetotelluric (AMT) sounding data collected in Spring Valley, NV show significant two-dimensional (2D) structure within the upper kilometer of the valley and help define the shallow basement surface. We collected AMT data along two profiles in the southern part of Spring Valley in the Fall 2004, using the Geometrics StrataGem EH4 system, a four channel, natural and controlled-source tensor system recording in the range of 10 to 92,000 Hz. To augment the low signal in the natural field a transmitter of two horizontal-magnetic dipoles was used from 1,000 to 70,000 Hz. Profile A extends 12.6 km from the Fortification Range on the west across southern Spring Valley to the Limestone Hills in the east with soundings recorded every 200 m. Profile B is a 2-km long, roughly E-W trending line located at the northern margin of the Fortification Range, roughly parallel to and 12 km NW of Profile A, with sounding spacings of 200-400 m. Data were recorded with the electrical field (E) parallel and perpendicular to the regional geological strike direction. We computed our preferred two-dimensional, inverse models from the E perpendicular mode data using the conjugate gradient, finite-difference method of Rodi and Mackie (2001) and a 100 ohm-m half-space, starting model. Inverse models were also computed using both modes and an equivalent model resulted, with a slightly higher RMS fit, indicating the two-dimensionality of the structure. Various starting models were used to test the depth of investigation. The model along Profile A shows detailed structure within the alluvial basin. Preliminary interpretation shows a clear transition between unsaturated (200-500 ohm-m) and saturated alluvium/volcanic rocks (20-50 ohm-m) at roughly 100 m depth. Highly-resistive (>1000 ohm-m) carbonate rocks are clearly defined at the east end of Profile A, and the locations and dips of several range-front and inter-basin faults, which lack surface expression, are delineated throughout the

  1. La presa y el ninfeo del Sotillo (Alfaro, La Rioja: un conjunto monumental en la vía De Italia in Hispanias

    Directory of Open Access Journals (Sweden)

    José Antonio HERNÁNDEZ VERA

    2009-12-01

    Full Text Available RESUMEN: Se estudian los restos de una construcción romana localizada junto al río Alhama, en las inmediaciones de la ciudad de Graccurris (Alfaro, La Rioja. La obra fue expoliada ya en época antigua, por lo que apareció incompleta, con buena parte de los materiales arquitectónicos que formaban parte de ella desplazados de su posición original. Los restos en mejor estado de conservación corresponden a una presa construida con grandes sillares de arenisca. A partir de los materiales arquitectónicos aislados respetados por el expolio, se puede restituir un gran conjunto monumental que, además de la presa, contaba con una fuente o ninfeo y un pequeño templo. Se documenta el paso por el sitio de la vía De Italia in Hispanias, ya que apareció también un miliario de Augusto. Tras ser expoliada, la obra fue definitivamente sepultada por un potente estrato de aluvión aportado por una crecida del Alhama. En este estrato la excavación proporcionó material cerámico romano, sin restos de épocas posteriores, lo que permite datar esta inundación hacia finales del siglo II.ABSTRACT: A study is made of Román remains located beside the Alhama River near the city of Gracurris (Alfaro, La Rioja. The site had already been plundered in ancient times so it was incomplete when uncovered, and a large number of the architectural materials had been moved from their original positions. The remains that are in the best state of preservation are those of a dam built of large sandstone blocks. A large monumental group can be restored from the isolated architectural materials left that were not plundered, including a nymphaeum and a small temple, in addition to the dam. It can also be shown that the Román road De Italia in Hispanias went through this site, since an Augustan milestone has also been found. After having been plundered, the site was completely buried by a layer of alluvium brought by a rise in the Alhama River. Román ceramic materials were

  2. Fracture density and grain size controls on the relief structure of threshold landscapes

    Science.gov (United States)

    DiBiase, R.; Rossi, M. W.; Neely, A.

    2015-12-01

    A central goal in geomorphology is to untangle the competing controls of climate, tectonics, and rock strength on the topography and relief structure of mountain ranges. This is important for deciphering the history of climate and tectonics encoded in landscapes, predicting natural hazards, and quantifying critical zone processes. Incorporating rock strength into landscape evolution models has been a particularly challenging problem, because the factors that determine rock strength vary in importance depending on process. Here we propose a mechanism of hillslope-channel coupling by which tectonically-induced fracturing influences the relief structure of steep, rocky "threshold" landscapes by leading to A) increased fracture density in exposed bedrock outcrops, thereby limiting hillslope relief, and B) decreased grain size of channel bed material, thereby reducing the magnitude of fluvial incision thresholds and increasing the erosional efficiency of bedrock rivers. To test this hypothesis, we compare two contrasting landscapes in southern California—the eastern San Gabriel Mountains and the northern San Jacinto Mountains. The eastern San Gabriel Mountains rise 2 km in relief and exhibit high uplift and erosion rates due to active faulting along the Cucamonga thrust fault. Although bedrock on hillslopes is common, the exposed granitic and metamorphic basement rock is highly fractured at the decimeter or finer scale, and river channels are mantled with a thin layer of gravel-cobble alluvium. The northern San Jacinto Mountains, 80 km to the southeast, experience similar mean runoff and daily runoff variability, and are underlain by similar bedrock. Yet, despite an absence of active faulting, and erosion rates slower than the eastern San Gabriel Mountains by a factor of 5, the northern San Jacinto Mountains preserve one of the steepest escarpments in the contiguous US (2-3 km high), characterized by massive bedrock outcrops on hillslopes with meter-scale or larger

  3. Hydrologic resources management program and underground test area FY 1999 progress report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D K; Eaton, G F; Rose, T P; Moran, J E; Brachmann, A; McAninch, J E; Kersting, A B; Romanovski, V V; Martinelli, R E; Werner, J K Jr

    2000-07-01

    provides a means for rapidly measuring dilute concentrations of radionuclides with precision and abundance sensitivity comparable to TIMS. (6) Chapter 6 provides results of a characterization study of alluvium collected from the U-1a complex approximately 300 meters below ground surface in Yucca Flat. The purpose of this investigation was to provide information on particle size, mineralogical context, the proportion of primary and secondary minerals, and the texture of the reactive surface area that could be used to accurately model radionuclide interactions within Nevada Test Site alluvial basins (i.e., Frenchman Flat and Yucca Flat).

  4. Water and Carbon Fluxes in a Semi-Arid Region Floodplain: Multiple Approaches to Constrain Estimates of Seasonal- and Depth Dependent Fluxes at Rifle, Colorado

    Science.gov (United States)

    Tokunaga, T. K.; Wan, J.; Dong, W.; Kim, Y.; Williams, K. H.; Conrad, M. E.; Christensen, J. N.; Bill, M.; Faybishenko, B.; Hobson, C.; Dayvault, R.; Long, P. E.; Hubbard, S. S.

    2014-12-01

    The importance of floodplains as links between watersheds and rivers highlights the need to understand water and carbon fluxes within floodplain profiles, from their surface soil, through the vadose zone and underlying groundwater. Here, we present results of field and laboratory measurements conducted to quantify fluxes at a remediated uranium/vanadium mill tailings site on a floodplain at Rifle, Colorado. This semi-arid site has a vegetated, locally derived fill soil that replaced the original milling-contaminated soil to a depth of about 1.5 m. The fill soil overlies about 4.5 m of native sandy and cobbly alluvium containing the shallow aquifer. The aquifer generally drains into the Colorado River and is underlain by low permeability Wasatch Formation shale. Within this system, key issues being investigated include water and carbon fluxes between the vadose zone and aquifer, and CO2 fluxes through the vadose zone soil out to the atmosphere. Magnitudes of these fluxes are typically low, thus challenging to measure, yet increasingly important to quantify given the expansion of arid and semi-arid regions under changing climate. The results of field investigations demonstrated that the annual water table rise and fall are driven by snowmelt runoff into the Colorado River in late spring to early summer. Tensiometer data indicate that net recharge from the deeper part of the vadose zone into groundwater occurs later in summer, after water table decline. The effectiveness of summer evapotranspiration in limiting groundwater recharge is reflected in water potentials decreasing to as low as -3 MPa within the upper 1.5 m of the vadose zone. Examination of the historical precipitation record further indicates that net recharge only occurs in years with above-average precipitation during winter and spring. These short intervals of net recharge also facilitate C transport into groundwater because of higher organic C concentrations in the vadose zone. Fluxes of CO2 measured

  5. Alluvial deposition and lake-level fluctuations forced by Late Quaternary climate change: the Dead Sea case example

    Science.gov (United States)

    Klinger, Y.; Avouac, J. P.; Bourles, D.; Tisnerat, N.

    2003-11-01

    Based on geomorphic observations, we discuss lake-level fluctuations, alluvial deposition and river entrenchment in the Dead Sea-Wadi Araba area. The bulk of alluvium in the northern Wadi Araba was probably deposited before the Lisan period of lake transgression that started at about 70 kyears B.P. The lake reached a maximum elevation about 150 m below sea level (b.s.l.), possibly around 15 cal. kyears B.P. as indicated by the highest preserved beach ridges. Cosmogenic exposure dates show that the ridge material consists mainly of remobilized Pleistocene gravel indicating little sediment supply during most of the Lisan period. During this period, a reduced sediment flux fed subaquatic fan deltas along the margin of the Dead Sea. Wetter conditions settled at the end of this period, the water level rose to about 280 m b.s.l. around 15 kyears B.P. and prevailed in the early Holocene (10.5-7 cal. kyears B.P.). Following that humid period, the lake level dropped and two major episodes of fluvial aggradation occurred during periods of relative low lake level. The first aggradational episode took place between about 7.0 and 6.2 cal. kyears B.P. Beach bars indicate a subsequent lake transgression between 6.2 and 4.4 kyears B.P. up to 350 m b.s.l. The second aggradational episode happened between 4.4 and 2.0 cal. kyears B.P., and was also followed by a late transgression up to 375 m b.s.l., dated to 1960-1715 cal. years B.P. The correlation between low lake level and fluvial aggradation is taken to reflect the synchronous change of the fluvial regime and of the lake hydrologic balance, forced by climate changes, rather than a base-level control. We also exclude large tectonic forcing on fan emplacement and river entrenchment. Alluviation appears in this setting as a very irregular process, characterized by long periods of quiescence alternating with periods of fan build-up, reflecting the transient response of the water drainage system to climate change.

  6. Seismic behaviour of the Dead Sea fault along Araba valley, Jordan

    Science.gov (United States)

    Klinger, Y.; Avouac, J. P.; Dorbath, L.; Karaki, N. Abou; Tisnerat, N.

    2000-09-01

    The Dead Sea fault zone is a major left-lateral strike-slip fault. South of the Dead Sea basin, the Wadi Araba fault extends over 160km to the Gulf of Aqaba. The Dead Sea fault zone is known to have produced several relatively large historical earthquakes. However, the historical events are unequally distributed along the fault and only four events have been reported in the Araba valley over the last few thousands of years. Magnitudes estimated from the historical record are probably slightly smaller than that’of the Mw~7.3 earthquake that struck the Gulf of Aqaba in 1995. The fault cuts straight across Pleistocene to Holocene alluvium and shows morphologic evidence for essentially pure strike-slip motion. Regional seismic monitoring reveals little microseismicity along the fault except around the Dead Sea and Gulf of Aqaba, where the fault splays into complex pull-apart basin fault systems. We have investigated the fault zone at several sites selected from SPOT images and the study of aerial photography. At the site of the now destroyed Tilah Castle, a well-preserved wall, dated to be about 1200yrBP (14C age on charcoal), is cut by the fault and offset by 2.2m. Comparison with offset gullies at a nearby site 3km to the north and at three other sites, respectively 25, 50 and 65km to the south, reveals that this specific fault displacement is probably related to the last seismic event that ruptured that fault segment, possibly in AD 1458. Moreover, the offset gullies suggest a characteristic slip behaviour with recurring slip of about 1.5m on average. Given the 4+/-2mmyr-1 slip rate derived for this fault segment, we infer that the fault should produce Mw~7 earthquakes along some segment in the Araba valley about every 200years. The historical period, with only four well-documented large earthquakes in AD 1068, AD 1212, AD 1293 and AD 1458, thus appears to have been relatively quiescent, with a 20 per cent deficit of Mw~7 earthquakes. However, our data do not

  7. The Ghost in the Machine: Fracking in the Earth's Complex Brittle Crust

    Science.gov (United States)

    Malin, P. E.

    2015-12-01

    This paper discusses in the impact of complex rock properties on practical applications like fracking and its associated seismic emissions. A variety of borehole measurements show that the complex physical properties of the upper crust cannot be characterized by averages on any scale. Instead they appear to follow 3 empirical rule: a power law distribution in physical scales, a lognormal distribution in populations, and a direct relation between changes in porosity and log(permeability). These rules can be directly related to the presence of fluid rich and seismically active fractures - from mineral grains to fault segments. (These are the "ghosts" referred to in the title.) In other physical systems, such behaviors arise on the boundaries of phase changes, and are studied as "critical state physics". In analogy to the 4 phases of water, crustal rocks progress upward from a un-fractured, ductile lower crust to nearly cohesionless surface alluvium. The crust in between is in an unstable transition. It is in this layer methods such as hydrofracking operate - be they in Oil and Gas, geothermal, or mining. As a result, nothing is predictable in these systems. Crustal models have conventionally been constructed assuming that in situ permeability and related properties are normally distributed. This approach is consistent with the use of short scale-length cores and logs to estimate properties. However, reservoir-scale flow data show that they are better fit to lognormal distributions. Such "long tail" distributions are observed for well productivity, ore vein grades, and induced seismic signals. Outcrop and well-log data show that many rock properties also show a power-law-type variation in scale lengths. In terms of Fourier power spectra, if peaks per km is k, then their power is proportional to 1/k. The source of this variation is related to pore-space connectivity, beginning with grain-fractures. We then show that a passive seismic method, Tomographic Fracture

  8. Detailed Geophysical Fault Characterization in Yucca Flat, Nevada Test Site, Nevada

    Science.gov (United States)

    Asch, Theodore H.; Sweetkind, Donald S.; Burton, Bethany L.; Wallin, Erin L.

    2009-01-01

    Yucca Flat is a topographic and structural basin in the northeastern part of the Nevada Test Site (NTS) in Nye County, Nevada. Between the years 1951 and 1992, 659 underground nuclear tests took place in Yucca Flat; most were conducted in large, vertical excavations that penetrated alluvium and the underlying Cenozoic volcanic rocks. Radioactive and other potential chemical contaminants at the NTS are the subject of a long-term program of investigation and remediation by the U.S. Department of Energy (DOE), National Nuclear Security Administration, Nevada Site Office, under its Environmental Restoration Program. As part of the program, the DOE seeks to assess the extent of contamination and to evaluate the potential risks to humans and the environment from byproducts of weapons testing. To accomplish this objective, the DOE Environmental Restoration Program is constructing and calibrating a ground-water flow model to predict hydrologic flow in Yucca Flat as part of an effort to quantify the subsurface hydrology of the Nevada Test Site. A necessary part of calibrating and evaluating a model of the flow system is an understanding of the location and characteristics of faults that may influence ground-water flow. In addition, knowledge of fault-zone architecture and physical properties is a fundamental component of the containment of the contamination from underground nuclear tests, should such testing ever resume at the Nevada Test Site. The goal of the present investigation is to develop a detailed understanding of the geometry and physical properties of fault zones in Yucca Flat. This study was designed to investigate faults in greater detail and to characterize fault geometry, the presence of fault splays, and the fault-zone width. Integrated geological and geophysical studies have been designed and implemented to work toward this goal. This report describes the geophysical surveys conducted near two drill holes in Yucca Flat, the data analyses performed, and the

  9. Detailed Geophysical Fault Characterization in Yucca Flat, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Theodore H. Asch; Donald Sweetkind; Bethany L. Burton; Erin L. Wallin

    2009-02-10

    Yucca Flat is a topographic and structural basin in the northeastern part of the Nevada Test Site (NTS) in Nye County, Nevada. Between the years 1951 and 1992, 659 underground nuclear tests took place in Yucca Flat; most were conducted in large, vertical excavations that penetrated alluvium and the underlying Cenozoic volcanic rocks. Radioactive and other potential chemical contaminants at the NTS are the subject of a long-term program of investigation and remediation by the U.S. Department of Energy (DOE), National Nuclear Security Administration, Nevada Site Office, under its Environmental Restoration Program. As part of the program, the DOE seeks to assess the extent of contamination and to evaluate the potential risks to humans and the environment from byproducts of weapons testing. To accomplish this objective, the DOE Environmental Restoration Program is constructing and calibrating a ground-water flow model to predict hydrologic flow in Yucca Flat as part of an effort to quantify the subsurface hydrology of the Nevada Test Site. A necessary part of calibrating and evaluating a model of the flow system is an understanding of the location and characteristics of faults that may influence ground-water flow. In addition, knowledge of fault-zone architecture and physical properties is a fundamental component of the containment of the contamination from underground nuclear tests, should such testing ever resume at the Nevada Test Site. The goal of the present investigation is to develop a detailed understanding of the geometry and physical properties of fault zones in Yucca Flat. This study was designed to investigate faults in greater detail and to characterize fault geometry, the presence of fault splays, and the fault-zone width. Integrated geological and geophysical studies have been designed and implemented to work toward this goal. This report describes the geophysical surveys conducted near two drill holes in Yucca Flat, the data analyses performed, and the

  10. Integrated Geophysical Measurements for Bioremediation Monitoring: Combining Spectral Induced Polarization, Nuclear Magnetic Resonance and Magnetic Methods

    Energy Technology Data Exchange (ETDEWEB)

    Keating, Kristina [Rutgers Univ., Newark, NJ (United States). Dept. of Earth and Environmental Sciences; Slater, Lee [Rutgers Univ., Newark, NJ (United States). Dept. of Earth and Environmental Sciences; Ntarlagiannis, Dimitris [Rutgers Univ., Newark, NJ (United States). Dept. of Earth and Environmental Sciences; Williams, Kenneth H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division

    2015-02-24

    were collected on columns of Rifle sediments during acetate amendment. The laboratory experiments were designed to simulate the field experiments; changes in geophysical signals were expected to correlate with changes in redox conditions and iron speciation. Field MS logging measurements revealed vertically stratified magnetic mineralization, likely the result of detrital magnetic fraction within the bulk alluvium. Little to no change was observed in the MS data suggesting negligible production of magnetic phases (e.g. magnetite, pyrrhotite) as a result of sulfidogenesis. Borehole NMR measurements contained high levels of noise contamination requiring significant signal processing, and analysis suggests that any changes may be difficult to differentiate from simultaneous changes in water content. Laboratory MS and NMR measurements remained relatively stable throughout the course of the acetate amendment experiment, consistent with field measurements. However, SIP measurements changed during the acetate amendment associated with the formation of iron-sulfide mineral phases; a finding that is consistent with chemical analysis of the solid phase materials in the columns.

  11. A hierarchical approach on groundwater-surface water interaction in wetlands along the upper Biebrza River, Poland

    Directory of Open Access Journals (Sweden)

    C. Anibas

    2011-10-01

    Full Text Available Groundwater-surface water exchange studies on natural rivers and wetlands dominated by organic soils are scarce. We present a hierarchical approach to quantitatively investigate and interpret groundwater-surface water interaction in space and time by applying a combination of different field methods including piezometer nests, temperature and seepage measurements. The numerical 1-D heat transport model of STRIVE is used in transient mode to calculate vertical fluxes from thermal profiles measured along the upper Biebrza River, Poland over a period of nine months. The calculated fluxes show no clear spatial pattern of exchange fluxes unless an interpolation of the point estimates on a reach scale is performed. Significance of differences in net exchange rates versus morphological features are investigated with statistical tests. Time series of temperature and hydraulic head of the hyporheic zone are used to estimate the temporal variability of the groundwater-surface water exchange. Seepage meter measurements and slug tests were used for cross validation of modelled fluxes. Results show a strong heterogeneity of the thermal and physical soil properties along the reach, leading to a classification of these parameters for modelling purposes. The groundwater-surface water exchange shows predominantly upward water fluxes, however alternating sections of recharge exist. The exchange fluxes are significantly different dependent on the position of the river in the valley floor and the river morphology where fluxes are more dependent on hydraulic gradients than on river bed conductivity. Sections of higher fluxes are linked to the vicinity of the morainic plateau surrounding the rivers alluvium and to meanders, indicating that a perspective on the fluvio-plain scale is required for interpreting the estimated exchange fluxes. Since the vertical component of the exchange fluxes cannot explain the magnitude of the change in river discharge, a lateral flow

  12. Variability in rainfall at monitoring stations and derivation of a long-term rainfall intensity record in the Grand Canyon Region, Arizona, USA

    Science.gov (United States)

    Caster, Joshua; Sankey, Joel B.

    2016-04-11

    can generate runoff which may erode alluvium. The characterization of past and present rainfall variability in this study will be useful for future studies that evaluate more spatially continuous datasets in order to better understand the rainfall dynamics within this, and potentially other, deep canyons.

  13. Predicting the aquatic stage sustainability of a restored backwater channel combining in-situ and airborne remotely sensed bathymetric models.

    Science.gov (United States)

    Jérôme, Lejot; Jérémie, Riquier; Hervé, Piégay

    2014-05-01

    As other large river floodplain worldwide, the floodplain of the Rhône has been deeply altered by human activities and infrastructures over the last centuries both in term of structure and functioning. An ambitious restoration plan of selected by-passed reaches has been implemented since 1999, in order to improve their ecological conditions. One of the main action aimed to increase the aquatic areas in floodplain channels (i.e. secondary channels, backwaters, …). In practice, fine and/or coarse alluvium were dredged, either locally or over the entire cut-off channel length. Sometimes the upstream or downstream alluvial plugs were also removed to reconnect the restored feature to the main channel. Such operation aims to restore forms and associated habitats of biotic communities, which are no more created or maintained by the river itself. In this context, assessing the sustainability of such restoration actions is a major issue. In this study, we focus on 1 of the 24 floodplain channels which have been restored along the Rhône River since 1999, the Malourdie channel (Chautagne reach, France). A monitoring of the geomorphologic evolution of the channel has been conducted during a decade to assess the aquatic stage sustainability of this former fully isolated channel, which has been restored as a backwater in 2004. Two main types of measures were performed: (a) water depth and fine sediment thickness were surveyed with an auger every 10 m along the channel centerline in average every year and a half allowing to establish an exponential decay model of terrestrialization rates through time; (b) three airborne campaigns (2006, 2007, 2012) by Ultra Aerial Vehicle (UAV) provided images from which bathymetry were inferred in combination with observed field measures. Coupling field and airborne models allows us to simulate different states of terrestrialization at the scale of the whole restore feature (e.g. 2020/2030/2050). Raw results indicate that terrestrialization

  14. Patterns and Processes of Width Adjustment to Increased Streamflows in Semi-Alluvial Rivers

    Science.gov (United States)

    Kelly, S. A.; Belmont, P.

    2015-12-01

    While it is understood that river channel width is determined by fluxes of water and sediment, predictive models of channel width, and especially changes in width under non-stationary conditions, have proven elusive. Classic hydraulic geometry relations commonly used in numerical models and channel design typically scale width as a power law function of discharge, without consideration of bank properties. This study investigates the role of bank material in determining spatial and temporal variability in channel width and widening rates for semi-alluvial rivers that have experienced increases in flow. The 45,000 km2 Minnesota River Basin contains many semi-alluvial rivers that have been rapidly incising into fine-grained glacial deposits over the last 13,400 years in response to a catastrophic base level drop. Large, recent increases in streamflows have caused significant channel widening and migration, exacerbated erosion of channel (alluvial) banks and (consolidated till) bluffs, and dramatically increased sediment supply. Here we leverage multiple decades of aerial photos, repeat lidar surveys, Structure from Motion photogrammetry and sediment gaging to examine past, and predict future, changes in channel width. We use empirical observations and a simple model to examine whether semi-alluvial channels tend toward a single, or multiple, equilibrium channel width(s). Preliminary results suggest that under stationary hydrologic conditions (1930s - 1970s) channel width was relatively consistent among reaches underlain by alluvium versus consolidated till. Since the late 1970s the study area has undergone profound hydrologic changes, with geomorphically-active flows nearly doubling in magnitude. Alluvial reaches widened relatively quickly in response to the increase in flows, whereas reaches underlain by till have not seen the same amount of widening. Aerial lidar-based geomorphic change detection between 2005 - 2012 records channel width changes in response to an

  15. Testing Novel CR-39 Detector Deployment System For Identification of Subsurface Fractures, Soda Springs, ID

    Energy Technology Data Exchange (ETDEWEB)

    McLing, Travis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Carpenter, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Brandon, William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zavala, Bernie [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    The Environmental Protection Agency (EPA) has teamed with Battelle Energy Alliance, LLC (BEA) at Idaho National Laboratory (INL) to facilitate further testing of geologic-fracture-identification methodology at a field site near the Monsanto Superfund Site located in Soda Springs, Idaho. INL has the necessary testing and technological expertise to perform this work. Battelle Memorial Institute (BMI) has engaged INL to perform this work through a Work for Others (WFO) Agreement. This study continues a multi-year collaborative effort between INL and EPA to test the efficacy of using field deployed Cr-39 radon in soil portals. This research enables identification of active fractures capable of transporting contaminants at sites where fractures are suspected pathways into the subsurface. Current state of the art methods for mapping fracture networks are exceedingly expensive and notoriously inaccurate. The proposed WFO will evaluate the applicability of using cheap, readily available, passive radon detectors to identify conductive geologic structures (i.e. fractures, and fracture networks) in the subsurface that control the transport of contaminants at fracture-dominated sites. The proposed WFO utilizes proven off-the-shelf technology in the form of CR-39 radon detectors, which have been widely deployed to detect radon levels in homes and businesses. In an existing collaborative EPA/INL study outside of this workscope,. CR-39 detectors are being utilized to determine the location of active transport fractures in a fractured granitic upland adjacent to a landfill site at the Fort Devens, MA that EPA-designated as National Priorities List (NPL) site. The innovative concept of using an easily deployed port that allows the CR-39 to measure the Rn-222 in the soil or alluvium above the fractured rock, while restricting atmospheric Rn-222 and soil sourced Ra from contaminating the detector is unique to INL and EPA approach previously developed. By deploying a series of these

  16. Hydrogeology of Cibola County, New Mexico

    Science.gov (United States)

    Baldwin, J.A.; Rankin, D.R.

    1995-01-01

    The hydrogeology of Cibola County, New Mexico, was evaluated to determine the occurrence, availability, and quality of ground-water resources. Rocks of Precambrian through Quaternary age are present in Cibola County. Most rocks are sedimentary in origin except for Precambrian igneous and metamorphic rocks exposed in the Zuni Uplift and Tertiary and Quaternary basalts in northern and central parts of the county. The most productive aquifers in the county include (youngest to oldest) Quaternary deposits, sandstones in the Mesaverde Group, the Dakota-Zuni-Bluff aquifer, the Westwater Canyon aquifer, the Todilto- Entrada aquifer, sandstone beds in the Chinle Formation, and the San Andres-Glorieta aquifer. Unconsolidated sand, silt, and gravel form a mantle ranging from a few inches to 150 to 200 feet over much of the bedrock in Cibola County. Well yields range from 5 to 1,110 gallons per minute. Dissolved-solids concentrations of ground water range from 200 to more than 5,200 milligrams per liter. Calcium, magnesium, bicarbonate, and sulfate are the predominant ions in ground water in alluvial material. The Mesaverde Group mainly occurs in three areas of the county. Well yields range from less than 1 to 12 gallons per minute. The predominant ions in water from wells in the Mesaverde Group are calcium, sodium, and bicarbonate. The transition from calcium-predominant to sodium-predominant water in the southwestern part of the county likely is a result of ion exchange. Wells completed in the Dakota-Zuni-Bluff aquifer yield from 1 to 30 gallons per minute. Dissolved-solids concentrations range from 220 to 2,000 milligrams per liter in water from 34 wells in the western part of the county. Predominant ions in the ground water include calcium, sodium, sulfate, and bicarbonate. Calcium predominates in areas where the aquifer is exposed at the surface or is overlain with alluvium. Sandstones in the Chinle Formation yield from 10 to 300 gallons per minute to wells in the Grants

  17. Remote sensing of acid sulfate soils using multispectral and gamma-ray data

    International Nuclear Information System (INIS)

    Acid sulfate soils are a significant environmental problem in coastal regions of Australia. Drainage and disturbance of coastal lands can result in acid soil degradation and the release of sulfuric acid and toxic metals into coastal waters. Remote sensing can provide a useful tool for detection of these soils and monitoring of their disturbance. As acid sulfate soils become oxidised with exposure to air, iron-minerals are produced and precipitate at the surface. This results from the breakdown of pyrite to form hydrated iron minerals and elemental sulfur, the oxidation of which produces acidity. The concentration of iron minerals at the surface can be an indicator of the level of acid sulfate soil activity in the near subsurface. These iron minerals include goethite, ferrihydrite and jarosite. Space-borne remote sensing scanners such as Landsat TM are capable of detecting iron minerals as a result of ferric ion absorption of solar radiation. Hyperspectral scanners are capable of further discrimination of individual minerals. This paper will discuss spectral characteristics of active acid sulfate soils and demonstrate the use of spectral unmixing algorithms on Landsat TM to detect problem areas at the surface. This method matches multispectral data to material reflectance-spectra known as end-members. These end-members or materials are then resolved mathematically as to their respective contributions to the overall reflectance (Bierwirth, 1990). In this way, abundances for particular materials can be derived.Digital elevation data was used to distinguish between the iron minerals due to weathering of bedrock in upland areas and acid sulfate soils on the plains. Also, the results of a high resolution (200m linespacing) airborne gamma-ray survey are presented. This data senses the concentration of radioelements down to about 40 cm depth and is largely unaffected by vegetation. Concentrations of gamma-emitting elements can indicate the type and depth of alluvium that

  18. Multispectral Thermal Imagery and Its Application to the Geologic Mapping of the Koobi Fora Formation, Northwestern Kenya

    Energy Technology Data Exchange (ETDEWEB)

    Green, Mary K. [Univ. of New Mexico, Albuquerque, NM (United States)

    2005-12-01

    The Koobi Fora Formation in northwestern Kenya has yielded more hominin fossils dated between 2.1 and 1.2 Ma than any other location on Earth. This research was undertaken to discover the spectral signatures of a portion of the Koobi Fora Formation using imagery from the DOE's Multispectral Thermal Imager (MTI) satellite. Creation of a digital geologic map from MTI imagery was a secondary goal of this research. MTI is unique amongst multispectral satellites in that it co-collects data from 15 spectral bands ranging from the visible to the thermal infrared with a ground sample distance of 5 meters per pixel in the visible and 20 meters in the infrared. The map was created in two stages. The first was to correct the base MTI image using spatial accuracy assessment points collected in the field. The second was to mosaic various MTI images together to create the final Koobi Fora map. Absolute spatial accuracy of the final map product is 73 meters. The geologic classification of the Koobi Fora MTI map also took place in two stages. The field work stage involved location of outcrops of different lithologies within the Koobi Fora Formation. Field descriptions of these outcrops were made and their locations recorded. During the second stage, a linear spectral unmixing algorithm was applied to the MTI mosaic. In order to train the linear spectra unmixing algorithm, regions of interest representing four different classes of geologic material (tuff, alluvium, carbonate, and basalt), as well as a vegetation class were defined within the MTI mosaic. The regions of interest were based upon the aforementioned field data as well as overlays of geologic maps from the 1976 Iowa State mapping project. Pure spectra were generated for each class from the regions of interest, and then the unmixing algorithm classified each pixel according to relative percentage of classes found within the pixel based upon the pure spectra values. A total of four unique combinations of geologic

  19. U-Sries Disequilibra in Soils, Pena Blanca Natural Analog, Chihuahua, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    D. French; E. Anthony; P. Goodell

    2006-03-16

    The Nopal I uranium deposit located in the Sierra Pena Blanca, Mexico. The deposit was mined in the early 1980s, and ore was stockpiled close by. This stockpile area was cleared and is now referred to as the Prior High Grade Stockpile (PHGS). Some of the high-grade boulders from the site rolled downhill when it was cleared in the 1990s. For this study soil samples were collected from the alluvium surrounding and underlying one of these boulders. A bulk sample of the boulder was also collected. Because the Prior High Grade Stockpile had no ore prior to the 1980s a maximum residence time for the boulder is about 25 years, this also means that the soil was at background as well. The purpose of this study is to characterize the transport of uranium series radionuclides from ore to the soil. Transport is characterized by determining the activities of individual radionuclides and daughter to parent ratios. Isotopes of the uranium series decay chain detected include {sup 210}Pb, {sup 234}U, {sup 230}Th, {sup 226}Ra, {sup 214}Pb, and {sup 214}Bi. Peak areas for each isotope are determined using gamma-ray spectroscopy with a Canberra Ge (Li) detector and GENIE 2000 software. The boulder sample is close to secular equilibrium when compared to the standard BL-5 (Beaver Lodge Uraninite from Canada). Results for the soils, however, indicate that some daughter/parent pairs are in secular disequilibrium. These daughter/parent (D/P) ratios include {sup 230}Th/{sup 234}U, which is greater than unity, {sup 226}Ra/{sup 230}Th, which is also greater than unity, and {sup 210}Pb/{sup 214}Bi, which is less than unity. The gamma-ray spectrum for organic material lacks {sup 230}Th peaks, but contains {sup 234}U and {sup 226}Ra, indicating that plants preferentially incorporate {sup 226}Ra. Our results, combined with previous studies require multistage history of mobilization of the uranium series radionuclides. Earlier studies at the ore zone could limit the time span for mobilization only

  20. Palynofacial analysis in alkaline soils and paleoenvironmental implications: The Paso Otero 5 archaeological site (Necochea district, Buenos Aires province, Argentina)

    Science.gov (United States)

    Grill, S.; Borromei, A.; Martínez, G.; Gutierrez, M. A.; Cornou, M. E.; Olivera, D.

    2007-06-01

    The combination of palynofacial and sedimentological analyses constitutes a valuable method for paleoenvironmental and paleoclimatic reconstructions, especially when fossil pollen information is scarce or absent. This methodology elucidates a late Pleistocene/Holocene sequence at the Paso Otero 5 archaeological site in the middle basin of the Quequén Grande River, Necochea district, Buenos Aires province, Argentina. Although the main factor responsible for the destruction of pollen grains is pH, biochemical and chemical oxidation and mechanical damage contribute to the deterioration as well. The site sequence indicates that extremely arid climatic conditions without vegetation cover prevailed during the late Pleistocene (˜12,000 14C yr BP), after which the climate changed to semiarid conditions associated with a disturbed environment due to strong eolian activity (Palynofacies 1 and 2; pre-10,400 14C yr BP). During the Pleistocene/Holocene transition (Palynofacies 3 and 4; ˜10,400-9400 14C yr BP), loamy facies associated with paleosoils reflected stable conditions and temporary ponds (spring deposits). Similar conditions occurred near the end of early Holocene (Palynofacies 5-9; ˜9400-6600 14C yr BP), whereas sandy and silty facies are associated with the flood margins of streams or rivers in the middle and late Holocene (Palynofacies 10-14; 6600-2500 14C yr BP). The top of the sequence (Palynofacies 15 and 16) consists of alluvium sediments and reflects locally humid conditions and modern vegetation with anthropic influence. One of the earliest Pampean sites with evidence of humans (10,450-10,200 14C yr BP), Paso Otero 5, provides a variety of megafauna bone specimens associated with ``fish-tail" projectile points, a lithic artifact diagnostic of early human occupations in South America. The site contains a complete stratigraphic record from the late Pleistocene to the present. The evidence presented herein supports the hypothesis that human colonization, at

  1. Analysis of Radionuclide Migration Through a 200-m Vadose Zone Following a 16-Year Infiltration Event

    Energy Technology Data Exchange (ETDEWEB)

    Tompson, A F B; Smith, D K; Hudson, G B

    2002-01-31

    The CAMBRIC nuclear test was conducted beneath Frenchman Flat at the Nevada Test Site on May 14, 1965. The nuclear device was emplaced in heterogeneous alluvium, approximately 70 m beneath the ambient water table, which is itself 220 m beneath the ground surface. Approximately 10 years later, groundwater adjacent to the test was pumped steadily for 16 years to elicit information on radionuclide migration in the saturated zone. The pumping well effluent--containing mostly soluble radionuclides such as tritium, {sup 14}C, {sup 36}Cl, {sup 85}Kr, {sup 129}I, and {sup 106}Ru--was monitored, discharged to an unlined ditch, and allowed to flow towards Frenchman Lake just over one kilometer away. Water discharged into the ditch infiltrated into the ground during flow along the ditch. This created an unexpected and remarkable second experiment in which the migration of the effluent through the 220 meters of unsaturated media, or ''vadose zone'', back to the water table, could be studied. In this paper, the pumping and effluent data are being utilized in conjunction with a series of geologic data, new radionuclide measurements, isotopic age-dating estimates, and vadose zone flow and transport models to better understand the movement of radionuclides between the ditch and the water table. Measurements of radionuclide concentrations in water samples produced from a water table monitoring well 100m away from the ditch indicate rising levels of tritium since 1993. The detection of tritium in the monitoring well occurs approximately 16 years after its initial discharge into the ditch. Modeling and tritium age dating have suggested 3 to 5 years of this 16-year transit time occurred solely in the vadose zone. They also suggest considerable recirculation of the pumping well discharge back into the original pumping well. Surprisingly, no {sup 14}C was observed at the water table, suggesting its preferential retention, possibly due to precipitation or other

  2. Subsurface Nitrogen-Cycling Microbial Communities at Uranium Contaminated Sites in the Colorado River Basin

    Science.gov (United States)

    Cardarelli, E.; Bargar, J.; Williams, K. H.; Dam, W. L.; Francis, C.

    2015-12-01

    Throughout the Colorado River Basin (CRB), uranium (U) persists as a relic contaminant of former ore processing activities. Elevated solid-phase U levels exist in fine-grained, naturally-reduced zone (NRZ) sediments intermittently found within the subsurface floodplain alluvium of the following Department of Energy-Legacy Management sites: Rifle, CO; Naturita, CO; and Grand Junction, CO. Coupled with groundwater fluctuations that alter the subsurface redox conditions, previous evidence from Rifle, CO suggests this resupply of U may be controlled by microbially-produced nitrite and nitrate. Nitrification, the two-step process of archaeal and bacterial ammonia-oxidation followed by bacterial nitrite oxidation, generates nitrate under oxic conditions. Our hypothesis is that when elevated groundwater levels recede and the subsurface system becomes anoxic, the nitrate diffuses into the reduced interiors of the NRZ and stimulates denitrification, the stepwise anaerobic reduction of nitrate/nitrite to dinitrogen gas. Denitrification may then be coupled to the oxidation of sediment-bound U(IV) forming mobile U(VI), allowing it to resupply U into local groundwater supplies. A key step in substantiating this hypothesis is to demonstrate the presence of nitrogen-cycling organisms in U-contaminated, NRZ sediments from the upper CRB. Here we investigate how the diversity and abundances of nitrifying and denitrifying microbial populations change throughout the NRZs of the subsurface by using functional gene markers for ammonia-oxidation (amoA, encoding the α-subunit of ammonia monooxygenase) and denitrification (nirK, nirS, encoding nitrite reductase). Microbial diversity has been assessed via clone libraries, while abundances have been determined through quantitative polymerase chain reaction (qPCR), elucidating how relative numbers of nitrifiers (amoA) and denitrifiers (nirK, nirS) vary with depth, vary with location, and relate to uranium release within NRZs in sediment

  3. U-Series Disequilibria in Soils, Pena Blanca Natural Analog, Chihuahua, Mexico

    International Nuclear Information System (INIS)

    The Nopal I uranium deposit located in the Sierra Pena Blanca, Mexico. The deposit was mined in the early 1980s, and ore was stockpiled close by. This stockpile area was cleared and is now referred to as the Prior High Grade Stockpile (PHGS). Some of the high-grade boulders from the site rolled downhill when it was cleared in the 1990s. For this study soil samples were collected from the alluvium surrounding and underlying one of these boulders. A bulk sample of the boulder was also collected. Because the Prior High Grade Stockpile had no ore prior to the 1980s a maximum residence time for the boulder is about 25 years, this also means that the soil was at background as well. The purpose of this study is to characterize the transport of uranium series radionuclides from ore to the soil. Transport is characterized by determining the activities of individual radionuclides and daughter to parent ratios. Isotopes of the uranium series decay chain detected include 210Pb, 234U, 230Th, 226Ra, 214Pb, and 214Bi. Peak areas for each isotope are determined using gamma-ray spectroscopy with a Canberra Ge (Li) detector and GENIE 2000 software. The boulder sample is close to secular equilibrium when compared to the standard BL-5 (Beaver Lodge Uraninite from Canada). Results for the soils, however, indicate that some daughter/parent pairs are in secular disequilibrium. These daughter/parent (D/P) ratios include 230Th/234U, which is greater than unity, 226Ra/230Th, which is also greater than unity, and 210Pb/214Bi, which is less than unity. The gamma-ray spectrum for organic material lacks 230Th peaks, but contains 234U and 226Ra, indicating that plants preferentially incorporate 226Ra. Our results, combined with previous studies require multistage history of mobilization of the uranium series radionuclides. Earlier studies at the ore zone could limit the time span for mobilization only to a few thousand years. The contribution of this study is that the short residence time of the

  4. Fluvial system response to late Pleistocene-Holocene sea-level change on Santa Rosa Island, Channel Islands National Park, California

    Science.gov (United States)

    Schumann, R. Randall; Pigati, Jeffery S.; McGeehin, John P.

    2016-01-01

    Santa Rosa Island (SRI) is one of four east-west aligned islands forming the northern Channel Islands chain, and one of the five islands in Channel Islands National Park, California, USA. The island setting provides an unparalleled environment in which to record the response of fluvial systems to major changes of sea level. Many of the larger streams on the island occupy broad valleys that have been filled with alluvium and later incised to form steep- to vertical-walled arroyos, leaving a relict floodplain as much as 12–14 m above the present channel. The period of falling sea level between the end of the last interglacial highstand at ~ 80 ka and the last glacial lowstand at ~ 21 ka was marked by erosion and incision in the uplands and by deposition of alluvial sediment on the exposed marine shelf. Sea level rose relatively rapidly following the last glacial lowstand of − 106 m, triggering a shift from an erosional to a depositional sedimentary regime. Accumulation of sediment occurred first through vertical and lateral accretion in broad, shallow channels on the shelf. Channel avulsion and delta sedimentation produced widespread deposition, creating lobes or wedges of sediment distributed across relatively large areas of the shelf during the latest Pleistocene. Backfilling of valleys onshore (landward of present sea level) appears to have progressed in a more orderly and predictable fashion throughout the Holocene primarily because the streams were confined to their valleys. Vertical aggradation locally reduced stream gradients, causing frequent overbank flooding and lateral channel shift by meandering and/or avulsion. Local channel gradient and morphology, short-term climate variations, and intrinsic controls also affected the timing and magnitudes of these cut, fill, and flood events, and are reflected in the thickness and spacing of the episodic alluvial sequences. Floodplain aggradation within the valleys continued until at least 500 years ago

  5. The Advantage of the Second Military Survey in Fluvial Measures

    Science.gov (United States)

    Kovács, G.

    2009-04-01

    suggested us to investigate the neotectonic features, what also indicated by the alternate meandering of surveyed streams. After geocoding the maps of the area, the streams were digitised, and their sinuosity values were calculated. At places significant difference of sinuosity has been observed along the streams, it can be considered as indicators of differential uplift or subsidence of the bedrock/alluvium. This method can be useful in general, if the watercourses mapped in the historical map are assumed to be unaffected by human.

  6. Site-Scale Saturated Zone Flow Model

    Energy Technology Data Exchange (ETDEWEB)

    G. Zyvoloski

    2003-12-17

    The purpose of this model report is to document the components of the site-scale saturated-zone flow model at Yucca Mountain, Nevada, in accordance with administrative procedure (AP)-SIII.lOQ, ''Models''. This report provides validation and confidence in the flow model that was developed for site recommendation (SR) and will be used to provide flow fields in support of the Total Systems Performance Assessment (TSPA) for the License Application. The output from this report provides the flow model used in the ''Site-Scale Saturated Zone Transport'', MDL-NBS-HS-000010 Rev 01 (BSC 2003 [162419]). The Site-Scale Saturated Zone Transport model then provides output to the SZ Transport Abstraction Model (BSC 2003 [164870]). In particular, the output from the SZ site-scale flow model is used to simulate the groundwater flow pathways and radionuclide transport to the accessible environment for use in the TSPA calculations. Since the development and calibration of the saturated-zone flow model, more data have been gathered for use in model validation and confidence building, including new water-level data from Nye County wells, single- and multiple-well hydraulic testing data, and new hydrochemistry data. In addition, a new hydrogeologic framework model (HFM), which incorporates Nye County wells lithology, also provides geologic data for corroboration and confidence in the flow model. The intended use of this work is to provide a flow model that generates flow fields to simulate radionuclide transport in saturated porous rock and alluvium under natural or forced gradient flow conditions. The flow model simulations are completed using the three-dimensional (3-D), finite-element, flow, heat, and transport computer code, FEHM Version (V) 2.20 (software tracking number (STN): 10086-2.20-00; LANL 2003 [161725]). Concurrently, process-level transport model and methodology for calculating radionuclide transport in the saturated zone at Yucca

  7. Groundwater flow modelling of Yamuna–Krishni interstream, a part of central Ganga Plain Uttar Pradesh

    Indian Academy of Sciences (India)

    Izrar Ahmed; Rashid Umar

    2009-10-01

    Groundwater is a major source of water for agricultural and domestic requirements in western Uttar Pradesh.Due to increasing agricultural requirements the abstraction of groundwater has increased manifold in the last two-to-three decades.The quaternary alluvium hosts the aquifer in the region.The study area forms a part of Yamuna –Krishni inter fluve.Although the area hosts potential aquifers these have been adversely affected by poor management.For effective ground water management of a basin it is essential that a careful water balance study should be carried out. Keeping this in mind groundwater flow modelling was attempted to simulate the behaviour of the flow system and evaluate the water balance.The groundwater flow modelling was carried out.The horizontal flows,seepage losses from unlined canals,recharge from rainfall and irrigation return flows were applied using different boundary packages available in Visual MODFLOW