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Sample records for alluvium

  1. 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.

  2. Diffusion of electromagnetic eddy currents in unconsolidated alluvium

    Science.gov (United States)

    Gilliland, E. S.; Weiss, C. J.

    2007-12-01

    Recent studies on the diffusive transport of electromagnetic eddy currents in complex geologic materials have invited speculation on novel theoretical frameworks to encapsulate the macroscopic effects of multi-scale geologic complexity. These ideas have been based on a limited amount of data from a restricted suite of geologic environments. To test the veracity of the various diffusion theories proposed in the literature, a new data set is presented here which consists of transient electromagnetic data collected over an alluvial fill aquifer in the Estancia Basin of central New Mexico. Geologic mapping and correlation of historical well-log data show the experiment site to consist of mainly unconsolidated felsic alluvium with intermittent cobble horizons. Analysis of the electromagnetic data in terms of its diagnostic move-out behavior of the source wavelet shows some similarity to previously obtained results in floodplain environments. Further analysis of the data shows that this behavior is dominated by the alluvial texture and not influenced by the underlying basement rock.

  3. The Sorption/Desorption Behavior of Uranium in Transport Studies Using Yucca Mountain Alluvium

    Energy Technology Data Exchange (ETDEWEB)

    Scism, Cynthia D. [Univ. of New Mexico, Albuquerque, NM (United States)

    2005-12-01

    Yucca Mountain, Nevada is the proposed site of a geologic repository for the disposal of spent nuclear fuel and high-level radioactive waste in the United States. In the event repository engineered barriers fail, the saturated alluvium located south of Yucca Mountain is expected to serve as a natural barrier to the migration of radionuclides to the accessible environment. The purpose of this study is to improve the characterization of uranium retardation in the saturated zone at Yucca Mountain to support refinement of an assessment model. The distribution of uranium desorption rates from alluvium obtained from Nye County bore holes EWDP-19IM1, EWDP-10SA, EWDP-22SA were studied to address inconsistencies between results from batch sorption and column transport experiments. The alluvium and groundwater were characterized to better understand the underlying mechanisms of the observed behavior. Desorption rate constants were obtained using an activity based mass balance equation and column desorption experiments were analyzed using a mathematical model utilizing multiple sorption sites with different first-order forward and reverse reaction rates. The uranium desorption rate constants decreased over time, suggesting that the alluvium has multiple types of active sorption sites with different affinities for uranium. While a significant fraction of the initially sorbed uranium desorbed from the alluvium quite rapidly, a roughly equivalent amount remained sorbed after several months of testing. The information obtained through this research suggests that uranium may experience greater effective retardation in the alluvium than simple batch sorption experiments would suggest. Electron Probe Microanalysis shows that uranium is associated with both clay minerals and iron oxides after sorption to alluvial material. These results provide further evidence that the alluvium contains multiple sorption sites for uranium.

  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. 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.

  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. A field- and laboratory-based quantitative analysis of alluvium: Relating analytical results to TIMS data

    Science.gov (United States)

    Wenrich, Melissa L.; Hamilton, Victoria E.; Christensen, Philip R.

    1995-01-01

    Thermal Infrared Multispectral Scanner (TIMS) data were acquired over the McDowell Mountains northeast of Scottsdale, Arizona during August 1994. The raw data were processed to emphasize lithologic differences using a decorrelation stretch and assigning bands 5, 3, and 1 to red, green, and blue, respectively. Processed data of alluvium flanking the mountains exhibit moderate color variation. The objective of this study was to determine, using a quantitative approach, what environmental variable(s), in the absence of bedrock, is/are responsible for influencing the spectral properties of the desert alluvial surface.

  8. Reactive transport of metal contaminants in alluvium - Model comparison and column simulation

    Science.gov (United States)

    Brown, J.G.; Bassett, R.L.; Glynn, P.D.

    2000-01-01

    A comparative assessment of two reactive-transport models, PHREEQC and HYDROGEOCHEM (HGC), was done to determine the suitability of each for simulating the movement of acidic contamination in alluvium. For simulations that accounted for aqueous complexation, precipitation and dissolution, the breakthrough and rinseout curves generated by each model were similar. The differences in simulated equilibrium concentrations between models were minor and were related to (1) different units in model output, (2) different activity coefficients, and (3) ionic-strength calculations. When adsorption processes were added to the models, the rinseout pH simulated by PHREEQC using the diffuse double-layer adsorption model rose to a pH of 6 after pore volume 15, about 1 pore volume later than the pH simulated by HGC using the constant-capacitance model. In PHREEQC simulation of a laboratory column experiment, the inability of the model to match measured outflow concentrations of selected constituents was related to the evident lack of local geochemical equilibrium in the column. The difference in timing and size of measured and simulated breakthrough of selected constituents indicated that the redox and adsorption reactions in the column occurred slowly when compared with the modeled reactions. MINTEQA2 and PHREEQC simulations of the column experiment indicated that the number of surface sites that took part in adsorption reactions was less than that estimated from the measured concentration of Fe hydroxide in the alluvium.

  9. Organic carbon in floodplain alluvium: Signature of historic variations in erosion processes associated with deforestation, Waipaoa River basin, New Zealand

    Science.gov (United States)

    Gomez, Basil; Brackley, Hannah L.; Hicks, D. Murray; Neff, Hector; Rogers, Karyne M.

    2004-12-01

    We use C-org and δ13C to trace the origin of the alluvium deposited on the Waipaoa River floodplain at McPhail's Bend between 1853 and 2002. The overbank deposits exhibit a more positive range of δ13C values (-26.3 ± 0.6) than contemporary suspended sediment in transport at intermediate flows (-27.8 ± 0.2) when gully erosion releases most material to stream channels, reflecting the greater contribution made by shallow landsliding in the headwaters during large precipitation events. Overbank sediment associated with recent floods contains a higher (˜50%) amount of organic carbon than alluvium deposited by pre-1927 floods, which was derived from outcrops of weathered bedrock on steep, riparian hillslopes that were the primary sediment source before the soil-mantled hillslopes elsewhere in the headwaters of the basin were destabilized by deforestation. The recent alluvium resembles the Bw horizon of soils present on these hillslopes. Sediment deposited during floods generated by localized storms and an overbank event that did not feature widespread shallow landsliding also has a distinctive signature that provides an indication of its provenance. The organic carbon associated with the alluvium appears to be old (4031 ± 40 B.P., in the case of the carbon associated with sediment deposited in 2002) and to be derived from weathered Cretaceous and Tertiary sedimentary rocks.

  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. 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.

  12. Comparative uranium-thorium and thermoluminescence dating of weathered quaternary alluvium in the tropics of Northern Australia

    Science.gov (United States)

    Nanson, Gerald C.; Price, David M.; Short, Stephen A.; Young, Robert W.; Jones, Brian G.

    1991-05-01

    Thermoluminescence (TL) age determinations of alluvial sediments in the tropics are evaluated by comparison with U/Th age determinations of pedogenic accumulations in the alluvium of the lower Gilbert River, a large fan delta in the wet-dry tropics of northern Queensland, Australia. This study extends U/Th dating by applying it not only to calcretes, but also to Fe/Mn oxyhydroxide/oxide accumulations. While a direct correlation cannot be made between U/Th dates from secondary minerals and TL dates from the host sediments, both sets of data show broad consistency. In addition to providing a minima for acceptable TL ages, U/Th dates are useful for determining the chronology of pedogenesis/diagenesis. They show that calcretes and ferricretes have formed under similar climatic conditions in the wet-dry tropics of northern Australia during the late pleistocene. Beneath about 5-12 m the Gilbert fan delta consists of an extensive sand body older than 85,000 yr and probably about 120,000 yr in age, representative of a period of major fluvial activity not repeated since this time. Above are muds and fine sandy muds that extend uninterrupted to the present surface except in the downstream fan where they are bisected by a thin unit of medium sand that TL dates at 40,000-50,000 yr B.P. A system of sandy distributary channels over the fan surface represents an early Holocene fluvial phase probably more active than at present.

  13. 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.

  14. Isotopic and Hydraulic Head Evidence for Cross-formational Leakage of Saline Water From the Rio Grande Alluvium to the Hueco Bolson Aquifer, Trans-Pecos Texas

    Science.gov (United States)

    Hibbs, B. J.; Eastoe, C. J.; Bangs, E.; Reinert, S.

    2002-12-01

    The twin-cities of El Paso and Juarez share the water resources of the Hueco Bolson, a Tertiary and Quaternary basin fill aquifer that spans the international border. Artesian conditions existed in the El Paso-Juarez Valley during predevelopment times, and dilute groundwaters in the Hueco Bolson flowed upward and mixed with the mineralized water in the shallow Rio Grande alluvium (alluvial deposits less than 60 m thick). The hydraulic gradient has been reversed since predevelopment times by heavy municipal pumping in the Hueco Bolson aquifer, and many of the deeper wells in the El Paso-Juarez Valley have been retired due to salinity exceeding 1500 mg/L TDS. Previous studies based on groundwater modeling suggested that salinity increased in deeper wells due to induced leakage of saline water from the shallow Rio Grande alluvium. Hydrochemical, isotopic and hydraulic head data collected in this study support this model. Tritium levels in several deeper wells in the El Paso-Juarez Valley (screens set from 90 to 210 m) vary from 1.2 to 7.9 TU, indicating post-bomb water from leakage from the Rio Grande and Rio Grande alluvium. The hydraulic head gradient is oriented vertically downward between the alluvial and bolson aquifers, reaching 0.14 (27 m/189 m) in one well nest. Groundwater from the same well nest gives δ18O and δ2H values plotting along a mixing curve, representing evaporated and saline waters in shallow alluvial wells (-7.2 to -8.3 δ18O \\permil, -66 to -71 δ2H \\permil), meteoric and dilute waters in the deepest bolson well (-10.7 δ18O \\permil, -76 δ2H \\permil), and intermediate and mixed saline water in middle bolson wells (-9.8 to -10.3 δ18O \\permil, -76 to -77 δ2H \\permil).

  15. Physiographic soil map delineation for the Nile alluvium and desert outskirts in middle Egypt using remote sensing data of EgyptSat-1

    Directory of Open Access Journals (Sweden)

    A.A. Afify

    2010-12-01

    Full Text Available The objectives of this study are to produce a physiographic soil map with correlated attributes to be a base for extra modifiers within the land information system. This integrated data will serve the purposes of land use planning, precision farming practices and to be applied in other areas using the extrapolation approach. The Satellite data of EgyptSat-1 were projected on an area of Middle Egypt that represents unique physiographic features over portions of Beni Suef, El Fayoum, Helwan, and October Provinces. The spectral signatures of the land patterns were delineated by the visual interpretation using the physiographic approach, while soil taxa were categorized according to the key of Soil Taxonomy (USDA, 2010, resulting in two landscape categories. The first category includes older and developed parent materials, covering the following units: (a Pediplains of residual soils over limestone parent rock, having soils of Lithic Haplocalcids, loamy skeletal. (b Terraced old alluvial plains represent the formerly deposited alluvium that preceded the recent one of the River Nile alluvium. They includes soils of Typic Calcigypsids, loamy skeletal and old alluvial plain but are currently managed under cultivation. The soils are dominated by Typic Haplocalcids, loamy skeletal. (c Wadis that were shaped by the paleodrainage erosion, are currently subjected to the seasonal flush flooding and are sparsely vegetated including soils of Typic Torrifluvents, lamy skeletal (calcareous; Typic Torriorthents, sandy skeletal, and Typic Torriorthents, sandy. (d Aeolian plain “partly cultivated” includes soils of Typic Torripsamments (calcareous. The second category is a recent River Nile alluvium that formed the following units: (a Terraced recent alluvial plain “cultivated” includes soils of Entic Calcitorrerts, fine and Typic Haplotorrerts fine. (b Recent flat alluvial plain includes soils of Typic Haplotorrerts, fine. (c Meandering belt is aligning

  16. 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.

  17. 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.

  18. Water-quality data for the Missouri River and Missouri River alluvium near Weldon Spring, St. Charles County, Missouri, 1991--92

    Energy Technology Data Exchange (ETDEWEB)

    Kleeschulte, M.J.

    1993-12-31

    This report contains the water-quality data collected at two cross sections across the Missouri River and from monitoring wells in the Missouri River alluvium near Defiance, Missouri. The sampling results indicate the general water composition from the Missouri River changes with different flow conditions. During low-base flow conditions, the water generally contained about equal quantities of calcium and sodium plus potassium and similar quantities of bicarbonate and sulfate. During high-base flow conditions, water from the river predominantly was a calcium bicarbonate type. During runoff conditions, the water from the river was a calcium bicarbonate type, and sulfate concentrations were larger than during high-base flow conditions but smaller than during low-base flow conditions. The total and dissolved uranium concentrations at both the upstream and downstream cross sections, as well as from the different vertical samples across the river, were similar during each sampling event. However, sodium, sulfate, nitrate, and total and dissolved uranium concentrations varied with different flow conditions. Sodium and sulfate concentrations were larger during low-base flow conditions than during high-base flow or runoff conditions, while nitrate concentrations decreased during low-base flow conditions. Both total and dissolved uranium concentrations were slightly larger during runoff events than during low-base or high-base flow conditions.

  19. 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.

  20. 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).

  1. Processes affecting δ34S and δ18O values of dissolved sulfate in alluvium along the Canadian River, central Oklahoma, USA

    Science.gov (United States)

    Tuttle, Michele L.W.; Breit, George N.; Cozzarelli, Isabelle M.

    2009-01-01

    The δ34S and δ18O values for dissolved sulfate in groundwater are commonly used in aquifer studies to identify sulfate reservoirs and describe biogeochemical processes. The utility of these data, however, often is compromised by mixing of sulfate sources within reservoirs and isotope fractionation during sulfur redox cycling. Our study shows that, after all potential sulfate sources are identified and isotopically characterized, the δ34SSO4 and δ18OSO4 values differentiate processes such as sulfate-source mixing, sulfide oxidation, barite dissolution, and organosulfur decomposition. During bacterial reduction of sulfate, the values reflect kinetic sulfur isotope fractionation and exchange of oxygen isotopes between sulfate and water. Detailed analysis of the chemistry (Cl and SO4 concentrations) and isotopic composition (δ2HH2Oand δ18OH2O) of groundwater in an alluvial aquifer in Central Oklahoma, USA allowed the identification of five distinct end members that supply water to the aquifer (regional groundwater flowing into the study area, river water, leachate from a closed landfill that operated within the site, rain, and surface runoff). The δ34SSO4 and δ18OSO4 values in each end member differentiated three sources of sulfate: sulfate dissolved from Early to Late Permian rocks within the drainage basin (δ34SSO4 = 8–12‰ and δ18OSO4 = 10‰), iron sulfides oxidized by molecular oxygen during low water-table levels (δ34SSO4 = − 16‰ and δ18OSO4 = 10‰), and organosulfur compounds (predominately ester sulfates) from decomposition of vegetation on the surface and from landfill trash buried in the alluvium (δ34SSO4 = 8‰ and δ18OSO4 = 6‰). During bacterial reduction of these sulfate sources, similar isotope fractionation processes are recorded in the parallel trends of increasing δ34SSO4 and δ18OSO4 values. When extensive reduction occurs, the kinetic sulfur isotope fractionation (estimated by εH2S–SO4 = − 23

  2. Assessing water salinity along River Limón and Caño San Miguel irrigation paleochannel (Maracaibo, Venezuela) as affected by the balance of soluble salts in alluvium soils

    Science.gov (United States)

    Rodriguez, Raquel; Moreno, Juan; Hermosilla, Daphne; Gascó, Antonio

    2013-04-01

    The saline degradation of soils that are irrigated with brackish water is worrisome increasing worldwide, and it may further affect the salinity of fresh water in those streams flowing across. The problem that is caused by an increasing concentration of salts that are more soluble than gypsum depends on the quality of irrigation water, climatic aridity, and drainage limitations. All these conditions meet in the alluvium soils of River Limón basin that are crossed by Caño San Miguel irrigation paleochannel. River Limón's regulation by closing Manuelote and Tulé artificial reservoirs has diminished the input of water and sediments from flooding events, which exerted dilutive effects in the past. In addition, the balance of soluble salts in these soils has also registered further net accumulation during those extremely dry years happened before 2006, because the great dilution contribution of ombrogenic dammed water coming from rain has not been enough to compensate salts concentration generated by water evapotranspiration in those irrigated soils of the middle basin, particularly in the absence of superficial runoff and deep drainage. Considering those semi-arid climate conditions prevailing in the area (annual precipitation = 710 mm; potential evapotransporation = 2361 mm), it resulted that water analyses in River Limón showed a ten-fold increased maximum annual salinity concentration (March) along the stream; that is, an electric conductivity (Ce) of 0.37 dS•m-1 (at 25 °C) at Puente Carrasquero pumping station, where water for crop irrigation is subtracted, turns to 34.60 dS•m-1 (at 25 °C) at its base level in Puerto Mara, where it discharges to Lake Maracaibo. In addition, the quality of irrigation water from Caño San Miguel, which aggregates to those coming from River Limón at the pumping station located in Carrasquero just before running through the alluvium of this water stream, resulted pretty irregular. In short, it spanned form C1 to C4 soil

  3. 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

  4. Meander applications at landslides in alluvium valleys

    Science.gov (United States)

    Yilmaz, L.

    2012-04-01

    For calculation of bed variation in alluvial channels important bed configurations include meso-scale bed configurations, such as alternating bars (pools and riffles) and braided bars. It is important in river management to be able to predict water surface elevation, scour, and fill in alluvial channels under given flow conditions. Mathematical and physical models can be used in designing or planning for improvement of river channels and hydraulic structures. Several studies have been made to evaluate flow and bed variation in meandering channels (Engelund, 1974; Odgaard, 1986; Ikeda et al., 1987; Falcon and Kennedy, 1983; Kishi et al., 1983, Struiksma, 1985, and Struiksma et al., 1985). The bed variation at meandering channels is calculated by the continuity equation for bed load transport. Typical bed configurations and flows with alternating bars and braided bars are produced in straight channels, and thus the formation and migration of bars are predicted quantitatively. The results of model applications were carried out for the same situations as the mathematical model at the Technical University of Berlin, Institute Wasserbau and Wasserwirtschaft (Yilmaz, 1990), started with flat bed, continued until dz/ dt=0. Then the beds were solidified, and precise measurements of the bed configuration and the velocity were performed. Plan geometries of runs consist of a sine-generated curve and an asymmetrical meander loop, respectively. The latter is derived by a Fourier series analysis on several typical bends. The meso-scale bed configuration in alluvial streams is highly dependent on the width-depth ratio of the channel. The velocity measurements were made with small mechanical current meters fixed to a 1m high frame that rested on the bottom while measuring the lower points on the profile. The frame was suspended at different levels above the bottom to collect the data represented by the higher points. Velocity profiles are plotted semi-logarithmically with the dots representing field data and the smooth lines showing model predictions. The mean velocity was calculated from a fit to the entire data set, not for each profile. Smaller dunes (0.50 m high, 2 m long) were superimposed on the large sand wave. Smith and McLean (1977) estimated the roughness parameter for both the skin friction and the form drag due to the smaller dunes to be 0.141 cm3. Three different perturbations are recognized : 1. Alternating bars: The bed configuration reached an equilibrium state after one hour, and the quantitative and qualitative agreements are given. Sensitivity analyses of each term in Eqs. 2 and 3 into the development of alternating bars were also carried out. The term in the Eq. (3) dv/ds was found to play the most important role in developing alternating bars. 2. Braided bars : The calculated velocity vectors and bed configurations were given after one hour. Divergence and convergence of flow streamlines in a wide straight channel and the meso-scale bed configuration of braided bars can be clearly seen. 3. No bars: The calculated velocity vector and bed configuration were given after one hour. The velocity distributions are almost uniform and the bed configuration is two-dimensional with less scour and fill than in the case of alternating bars and braided bars.

  5. Additional stress of shaft linings in thick alluvium constructed by freezing process%冻结法成井井壁在深厚表土段附加应力研究

    Institute of Scientific and Technical Information of China (English)

    孟志强; 纪洪广; 彭飞

    2013-01-01

    为研究深厚表土段井壁的破坏机理,提高井筒的使用寿命,指导已破坏井筒维修和为新设计井筒提供依据,采用数值模拟和理论计算相结合的方法,对淮北煤田深厚表土段井壁附加应力的产生原因及大小进行了探讨.结果表明:附加应力由井壁和裹携土体重量产生,与地下水埋藏深度、土的容重、地下水层数有关,地下水埋藏越深,产生的附加应力越大,在基岩表面处的附加应力为89.91 MPa,远远超过了混凝土井壁的抗压强度.为避免井筒破坏,应采用方法是:增加井壁强度、保持原有水压、设法减少锥体的重量、井壁在应力集中处采用伸缩装置.%To analyze the failure mechanism of shaft lining in thick alluvium and improve its service life, direct reparation for broken shaft lining, and provide evidence for new shaft lining design, this paper researched the reasons of shaft lining additional stress in Huaibei coalfield, combined numerical simulation and theoretical calculations. The results show that the additional stress is generated by weight of shaft liner and incidental conical soil, which is related to the groundwater depths, soil bulk density, and groundwater layer number. The deeper the groundwater is, the larger the additional stress is. The additional stress in bedrock surface reaches 89. 91 MPa,which is far more than concrete com-pressive strength. In order to avoid shaft lining breakage, some measures are taken, for example, increasing shaft lining thickness, maintaining original hydraulic pressure, reducing the weight of incidental conical soil and using expansion device in stress concentration area.

  6. 厚冲积层下大采高综放工作面顶板控制机理与实践%Thick alluvium full-mechanized caving mining with large mining height face roof control mechanism and practice

    Institute of Scientific and Technical Information of China (English)

    马立强; 张东升; 孙广京; 崔泰贺; 周焘

    2013-01-01

    龙固煤矿主采煤层上覆基岩厚度平均不足200 m,但基岩上方赋存着厚度平均超过700 m的厚冲积层,针对厚冲积层条件下工作面矿山压力与顶板的控制难题,分析了大采高长壁综放工作面上覆厚冲积层在采动卸荷条件下的承载特性,以及基岩发生台阶下沉的可能性及其对应临界厚度.研究结果表明,厚冲积层在其底部煤层大范围开挖后,自承载能力不强,其自重将以载荷形式作用在下伏基岩上,但当基岩厚度大于120 m时,断裂带岩层可以形成稳定的力学承载结构,确定工作面顶板具有可控性.在此基础上,研发了工作阻力为国内最大的ZF15000/23/43综放支架,对厚冲积层下大采高综放面围岩进行了有效控制.%The average thickness of the overlying bedrock of Longgu primary mineable coalseam is less than 200 m, but there is a thick alluvium averaging above 700 m above the bedrock. The bearing characteristic of fully mechanized longwallcaving face with large mining height on the condition of unloading, the possibility of step sinking and its critical thickness are analyzed in order to solvethe problems of the mine pressure atmining face and strata control under-thick alluvium condition. The results show that, whileits bearing capacity is not strong after large excavation underthe bottom of deep alluvium and itsweight is loaded onthe underlying bedrock, the fracture zone can form a stable mechanical bearing structurewhen the thickness of the bedrock is more than 120 m,so the coalface roof canbe controlled. On this basis,ZF15000/23/43 hydraulic support has been developed,with the largest working resistance in China. With this hydraulic support,the surrounding rock in fully mechanized caving coalface with large mining height underthick alluvium can becontrolled.

  7. 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.

  8. FEATURES OF THE ALLUVIUM ON TANGXIAN SURFACE NEAR BAODE-FUGU AND ITS GEOMORPHOLOGIC IMPLICATIONS IN THE NORTHERN JINSHAAN GORGE, YELLOW RIVER%晋陕峡谷北段保德-府谷地区唐县面上冲积物的特征及其地貌意义

    Institute of Scientific and Technical Information of China (English)

    王小燕; 邱维理; 张家富; 李容全; 周力平

    2013-01-01

    Because of its complex history,the Yellow River is a good case for fluvial geomorphology studies.The Jinshaan Gorge is one of the key parts to understand the evolution of the Yellow River.Since 1922,researchers have made great progress in the study of the evolution of the Yellow River in the Jinshaan Gorge area.But there are some disputes still remained about the Tangxian Surface,an erosion surface formed in the Miocene and Pliocene,and the alluvium on it.The main divarication is whether the Tangxian Surface is a terrace of the Yellow River or the alluvium on the Tangxian Surface is formed by the ancient Yellow River.Baode-Fugu area,located in the north part of the Jinshaan Gorge,is famous for the Neogene red clay sediment in which Hipprion fauna is unearthed.The recent studies of red clay offer a chronological data to discuss the age of both the red clay,other contemporaneous sediment and the underneath erosion surface of Tangxian Stage.The present paper is based on the survey of eighteen sediment outcrops on the Tangxian Surface in the BaodeFugu area.Twenty one samples were collected from gravel layers for sediment analysis.A topographic profile across the Yellow River shows that there is a wide bedrock valley stretching along the modern Yellow River,which is about 170m above the river level.According to the previous magnetostratigraphic studies of the red clay and fluvial sediment,the Tangxian Surface was formed at least 8.OMa ago.Gravel statistic result shows that the gravel sitting on the Tangxian Surface is > 1.5 in the complexity index of components and is characterized by an average roundness of ca.2 or >2,i.e.sub-rounded and rounded,with a variance of >0.5.The rock type of the gravels indicates a mixture of distant and local source.Combining the evidences above,it is reasonable to conclude that there used to be a river flowing along a similar course direction of modern Yellow River in this region during the Middle Miocene.Though it is much smaller

  9. Source Physics Experiment Phase II, Dry Alluvium Geology (DAG) Experiments Using Nitromethane

    Energy Technology Data Exchange (ETDEWEB)

    Traeger, Scott R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-21

    Need to provide briefing to the State of Nevada as part of the Permitting process for the Nevada Chemical Accident Prevention Program (CAPP) for use of nitromethane at the NNSS. This document will be accessible to the public as part of the CAPP program.

  10. 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.

  11. Selected techniques for monitoring water movement through unsaturated alluvium during managed aquifer recharge

    Science.gov (United States)

    Nawikas, Joseph M.; O'Leary, David R.; Izbicki, John A.; Burgess, Matthew K.

    2016-10-21

    Managed aquifer recharge is used to augment natural recharge to aquifers. It can be used to replenish aquifers depleted by pumping or to store water during wetter years for withdrawal during drier years. Infiltration from ponds is a commonly used, inexpensive approach for managed aquifer recharge.At some managed aquifer-recharge sites, the time when infiltrated water arrives at the water table is not always clearly shown by water-level data. As part of site characterization and operation, it can be desirable to track downward movement of infiltrated water through the unsaturated zone to identify when it arrives at the water table.

  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...

  13. Late Quaternary chronostratigraphic framework of terraces and alluvium along the lower Ohio River, southwestern Indiana and western Kentucky, USA

    Science.gov (United States)

    Counts, Ronald C.; Murari, Madhav K.; Owen, Lewis A.; Mahan, Shannon; Greenan, Michele

    2015-01-01

    The lower Ohio River valley is a terraced fluvial landscape that has been profoundly influenced by Quaternary climate change and glaciation. A modern Quaternary chronostratigraphic framework was developed for the lower Ohio River valley using optically stimulated luminescence (OSL) dating and allostratigraphic mapping to gain insights into the nature of fluvial responses to glacial–interglacial/stadial–interstadial transitions and Holocene climate change. River deposits, T0 (youngest) to T7 (oldest), were mapped along a 75 km reach of the lower Ohio River and were dated using 46 OSL and 5 radiocarbon samples. The examination of cores combined with OSL and radiocarbon dating shows that fluvial sediments older than marine oxygen isotope stage (MIS) 2 are present only in the subsurface. Aggradation during MIS 6 (Illinoian glaciation) filled the valley to within ∼7 m of the modern floodplain, and by ∼114 ka (MIS 5e/Sangamon interglacial) the Ohio River had scoured the MIS 6 sediments to ∼22 m below the modern floodplain surface. There were no fluvial sediments in the valley with ages between MIS 5e and the middle of MIS 3. The MIS 3 ages (∼39 ka) and stratigraphic position of T5 deposits suggest the Ohio River aggraded 8–14 m during MIS 4 or MIS 3. Near the end of MIS 3, the Ohio River incised the mid Last Glacial (mid-Wisconsinan) deposits ∼10 m and began aggrading again by ∼30 ka. Aggradation continued into MIS 2, with maximum MIS 2 aggradation occurring before ∼21 ka, which is coincident with the global Last Glacial Maximum (LGM). As the Ohio River adjusted to changing fluxes in sediment load and discharge following the LGM, it formed a sequence of fill-cut terraces in the MIS 2 outwash that get progressively younger with decreasing elevation, ranging in age from ∼21 ka to ∼13 ka. From ∼14 ka to ∼13 ka the Ohio River rapidly incised ∼3 m to form a new terrace, and by ∼12 ka at the onset of the Holocene, the Ohio River established a meandering channel pattern. The river formed a broad floodplain surface from ∼12 ka to ∼6 ka, and then incised ∼1 m and formed a fill-cut terrace from ∼6 ka to ∼5 ka. After ∼5 ka, likely in response to mid-Holocene drought in North America, the Ohio River incised ∼5 m, and by ∼4 ka the river began aggrading again. The Ohio River has aggraded ∼4 m since aggradation began at ∼4 ka. The chronostratigraphic framework and reconstructed history developed here suggest that the lower Ohio River is highly sensitive to glacial–interglacial transitions and abrupt Holocene climate change and responds rapidly to these allogenic forcings.

  14. Determining treatment requirements for turbid river water to avoid clogging of aquifer storage and recovery wells in siliceous alluvium.

    Science.gov (United States)

    Page, Declan; Vanderzalm, Joanne; Miotliński, Konrad; Barry, Karen; Dillon, Peter; Lawrie, Ken; Brodie, Ross S

    2014-12-01

    The success of Aquifer Storage and Recovery (ASR) schemes relies on defining appropriate design and operational parameters in order to maintain high rates of recharge over the long term. The main contribution of this study was to define the water quality criteria and hence minimum pre-treatment requirements to allow sustained recharge at an acceptable rate in a medium-coarse sand aquifer. The source water was turbid, natural water from the River Darling, Australia. Three treatments were evaluated: bank filtration; coagulation and chlorine disinfection; and coagulation plus granular activated carbon and chlorine disinfection (GAC). Raw source water and the three treated waters were used in laboratory columns packed with aquifer material in replicate experiments in saturated conditions at constant temperature (19 °C) with light excluded for 37 days. Declines in hydraulic conductivity from a mean of 2.17 m/d occurred over the 37 days of the experiment. The GAC-treated water gave an 8% decline in hydraulic conductivity over the 16 cm length of columns, which was significantly different from the other three source waters, which had mean declines of 26-29%. Within the first 3 cm of column length, where most clogging occurred in each column, the mean hydraulic conductivity declined by 10% for GAC-treated water compared with 40-50% for the other source waters. There was very little difference between the columns until day 21, despite high turbidity (78 NTU) in the source water. Reducing turbidity by treatment was not sufficient to offset the reductions in hydraulic conductivity. Biological clogging was found to be most important as revealed by the accumulation of polysaccharides and bacterial numbers in columns when they were dissected and analysed at the end of the experiment. Further chemical clogging through precipitation of minerals was found not to occur within the laboratory columns, and dispersion of clay was also found to be negligible. Due to the low reduction in hydraulic conductivity, GAC-treated water quality was used to set pre-treatment targets for ASR injection of turbidity  0.2 mg/L.

  15. “ 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.

  16. 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...

  17. 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...

  18. Caracterização do enraizamento da beterraba sacarina (Beta vulgaris L. num solo de aluvião Rooting pattern of sugar beet (Beta vulgaris L. var. saccharifera in a soil from alluvium

    Directory of Open Access Journals (Sweden)

    C. M. Toureiro

    2007-01-01

    Full Text Available O conhecimento do padrão de enraizamento das culturas e sua evolução ao longo do ciclo cultural é importante para a gestão do uso da água e nutrientes do solo. A promoção de práticas de rega eficientes – como a condução da água de rega em tempo real numa determinada área – requer o conhecimento, para além de parâmetros meteorológicos e pedológicos, de parâmetros culturais, como duração dos estádios de desenvolvimento da cultura, coeficientes culturais, capacidade de aprofundamento radical, sensibilidade da cultura à deficiência hídrica, défice de gestão permissível e dos parâmetros que caracterizam as regas efectuadas durante a campanha (data e dotação de rega efectivamente aplicada e avaliação dos sistemas de rega utilizados. O presente estudo teve como objectivo avaliar o desenvolvimento da cultura da beterraba, num solo de aluvião (A – Solos Incipientes, Aluviossolo Moderno não Calcário de Textura Mediana, do Perímetro de Rega do Divor, cujo cenário de gestão da água de rega utilizado foi a optimização do rendimento óptimo da cultura. No ensaio realizado com a cultura da beterraba, durante a campanha de rega de 2004 (Primavera-Verão, utilizou-se o método do minirizotrão, com o qual é possível acompanhar as variações temporais e espaciais do desenvolvimento radical da cultura, permitindo uma caracterização do sistema radical como órgão dinâmico. Para além deste método procedeu-se à abertura de perfis, perpendicularmente à linha de cultura, até à profundidade de 50 cm. Em várias datas de observação durante o ciclo cultural, avaliou-se a capacidade de aprofundamento e peso do túberculo. Em complemento, avaliaram-se outros índices culturais tais como a duração dos estados fenológicos, o índice de área foliar (IAF, matéria verde da parte aérea e a produção total. Consideraram-se as seguintes épocas de observação: desenvolvimento vegetativo (0-69 dias após a sementeira (DAS; desenvolvimento vegetativo e formação do túberculo (69-166 DAS e maturação (166-196 DAS. Os resultados obtidos mostram o seguinte: 1 Relativamente aos parâmetros da parte aérea da cultura: os valores máximos relativos à massa verde e índice de área foliar ocorreram no período de 96-111 DAS, após o qual se registou um decréscimo acentuado dos valores, coincidindo com o início da senescência da parte aérea da cultura e o desenvolvimento rápido do tubérculo; e 2 Relativamente aos parâmetros radicais e tubérculo: a evolução da massa e da profundidade da localização do tubérculo foi crescente ao longo do ciclo, mais significativa a partir dos 96-111 DAS, atingindo os valores máximos de 2000 g e 40 cm, respectivamente, 196 DAS. Da análise sequencial das imagens obtidas com o minirizotrão, foi possível observar raízes finas (Ø Knowledge of plant rooting patterns and their evolution during the crop season is important for the apropriate soil water and nutrients management. The implementation of efficient irrigation practices – such as the irrigation management in real time for a certain area – needs information on meteorological, soil and crop parameters: such as crop growth stage, crop coefficients, paths of rooting depth, crop sensitivity to water stress, allowable soil water deficit, etc. Also, the characteristics of irrigation events should also be known, normally irrigation amount, opportunity, and evaluation. The objective of the present study is to evaluate a sugar beet crop growth including root growth pattern, on an Alluvial soil, under irrigation to give the crop the optimum water amount for maximum growth. The minirizotron method was used for monitoring root growth during crop season. Later on, trenches were opened for directly observing and measuring root development and pattern, up to 50 cm depth. Beet root depth and weight were evaluated at several points – growing stage from 0 to 69 days after seeding (DAS, yield formation from 69 to 166 DAS, and ripening from 166 to 196 DAS - and crop growth indices were also determined: leaf area index (LAI, and the duration of crop growing stages. Finally, biomass and grain production were evaluated. Data obtained showed that: 1 Maximum values for biomass and LAI were observed at 96 to 111 days, the values decreasing afterwards, while leaf senescence and rapid root growth occurred; and 2 Mass and depth of the beet root was observed to increase throughout the crop cicle, but faster between 96 and 111 DAS, reaching 2000 g and 40 cm respectively at 196 DAS. Images obtained with the minirizotron showed that fine beet roots had grown down to 90 cm depth.

  19. 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.

  20. Hydrogeologic Data of the Denver Basin, Colorado. Colorado Water Conservation Board Basic Data Report Number 15

    Science.gov (United States)

    1964-01-01

    sand: Overburden . 60 60 Sand and sandy snale 1 241 Topsoil and sand. . . 10 - 0 Dawson Formation (lower part): Shale. hard, blue. . . 245 ruviers ...upper part): Clay . 25 .50 Louviers Alluviums Shale. brown ,.... 17 55 ruviers Alluviums Boulders. sand, and Sandstone v-ater-bearinqj 21 𔄀 Gravel

  1. 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...

  2. Colorado Plateau Rapid Ecoregion Assessment Management Question B4: Where are the alluvial aquifers and their recharge areas (if known)?

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — This map shows potential alluvial aquifers based on sand, gravel, and alluvium types in the surficial geology datasets of Arizona, Colorado, New Mexico, and Utah.

  3. Hydrochemical evolution within a large alluvial groundwater resource overlying a shallow coal seam gas reservoir.

    Science.gov (United States)

    Owen, Daniel D R; Cox, Malcolm E

    2015-08-01

    A combination of multivariate statistical techniques, simple hydrochemical mixing models and inverse geochemical modelling was used to investigate the major hydrochemical evolutionary pathways of a large alluvial aquifer, the upper Condamine River alluvium, south-east Queensland, Australia. Hydrochemical similarities between alluvium and sedimentary bedrock groundwater imply some mixing between alluvial and sedimentary bedrock aquifers, but spatial assessment showed that this was localised around outcrops of sedimentary bedrock in upstream areas. Within the alluvium, a distinct shift towards a low salinity Na-HCO3 water type and a brackish Na-HCO3-Cl water type was obvious in two separate locations. Both of these water types are unique to the alluvium, and inverse modelling shows that they can evolve via a combination of in situ alluvial processes, including diffuse recharge of rainfall or river water or the evolution of basalt-derived groundwater via gypsum dissolution plagioclase weathering, cation exchange and some carbonate precipitation/dissolution. The evolution of these water types is potentially influenced by overlying sodic alkaline soils, and often is associated with a source of sulfate. Evapotranspiration is the dominant salinization process in the alluvium and increases in calcium cations during salinization indicate that brackish Na-HCO3-Cl groundwater in the underlying Walloon Coal Measures are unlikely to have a major influence on salinization in the alluvium. The most saline water types observed were endemic to shallow zones of the alluvium where evapotranspiration is likely. Results demonstrate that a combination of multivariate statistics and inverse geochemical modelling can be successfully used to delineate hydrochemical pathways in complex hydrogeological settings where a range of environmental and anthropogenic factors may be influencing the evolution of water types with similar hydrochemical compositions.

  4. 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.

  5. Radioactivity in groundwater along the borders of Oman and UAE

    DEFF Research Database (Denmark)

    Murad, A.; Alshamsi, D.; Hou, Xiaolin;

    2014-01-01

    are alluvium deposits (silt, sand and gravel) and the measured groundwater radioactivity (including 232Th, 238U, 235U, 226Ra, 222Rn, gross-α and gross-β) indicates values below the WHO permissible limits for drinking water. The results also show large difference in radioactivity fingerprints, in particular...... for 226Ra and 222Rn within the investigated aquifers. The data further indicate lower radioactivity in groundwater of the alluviums compared to the carbonate aquifers in the region. This feature makes the alluvium aquifers valuable reservoirs that should be carefully exploited as a source of groundwater....... As this is the first investigation on the radioactivity of groundwater in alluvial aquifers in the region, it suggests that other alluvial deposits, particularly those inland and far from the marine water intrusion or seepage from carbonate rocks would have low radioactivity fingerprints....

  6. Symposium on Engineering With Nuclear Explosives January 14-16, 1970 Las Vegas, Nevada. Volume 2

    Science.gov (United States)

    1970-05-01

    Minerals in Aqueous Suspension . Proceedings of the Australian IMM, No. 198, 1961, pp. 47-84. 17. . Copper Waste Dump Leaching. Proceedings of the...24/60- Basalt 40,000 3 25. 5, 42. 7. 0. 75, 1. 25, 59. 5-480 1. 74-140 7 00/27/60 58. 0 1. 72 Scooter 10/13/60 Alluvium 907,410 1e 125 1.25 300-6500 3...schooner II (0.02-0.07) Dry clay UET (0.06-0.12) Mole 100 series (0.05-0.19) NTS Scooter , Stagecoach Sandia I (not determinable) alluvium (0.02-0.06) Mole

  7. Biomass production on saline-alkaline soils

    Energy Technology Data Exchange (ETDEWEB)

    Chaturvedi, A.N.

    1985-01-01

    In a trial of twelve tree species (both nitrogen fixing and non-fixing) for fuel plantations on saline-alkaline soil derived from Gangetic alluvium silty clay, Leucaena leucocephala failed completely after showing rapid growth for six months. Results for other species at age two showed that Prosopis juliflora had the best productivity.

  8. Final Environmental Assessment for Installation Development at Little Rock Air Force Base Arkansas

    Science.gov (United States)

    2006-10-18

    of Paleozoic age. A thin drape of younger unconsolidated clays, sands, and gravel (alluvium), is often found in valley floors and is associated with...recovery of antifreeze, used oils and hydraulic fluids, containerizing chromium chips , recycling glass beads and paint chips from the paint stripping

  9. Supplement to the site observational work plan for the UMTRA project site at Ambrosia Lake, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    The purpose of this document is to provide additional and more detailed information to supplement review of the site observational work plan (SOWP) (DOE, 1995) for the Ambrosia Lake, New Mexico, Uranium Mill Tailings Remedial Action (UMTRA) Project site. This document includes a discussion of the average linear velocity of the ground water in the alluvium and a discussion of the ground water quality of the alluvium, weathered Mancos Shale, and the Tres Hermanos-C Member of the Mancos Shale. The data from a 1989 aquifer test were analyzed using the curve-matching software AQTESOLV and then compared with the original results. A hydrograph of the ground water elevations in monitoring wells screened in the alluvium is presented to show how the ground water elevations change with time. Stiff and Piper diagrams were created to describe the changes in ground water geochemistry in the alluvium/weathered Mancos Sahel unit, the Tres Hermanos-C Sandstone unit, the Tres Hermanos-B Sandstone unit, and the Dakota Sandstone. Background information on other related topics such as site history, cell construction, soil characteristics, and well construction are presented in the SOWP. A geologic cross section depicts the conceptual model of the hydrostratigraphy and ground water chemistry of the Ambrosia Lake site. Hydrogeologic information of each hydrostratigraphic unit is presented.

  10. Supplement to the site observational work plan for the UMTRA Project Site at Ambrosia Lake, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The purpose of this document is to provide additional and more detailed information to supplement review of the site observational work plan (SOWP) for the Ambrosia Lake, New Mexico, Uranium Mill Tailings Remedial Action (UMTRA) Project site. This document includes a discussion of (1) the average linear velocity of the ground water in the alluvium; (2) the ground water quality of the alluvium, weathered Mancos Shale, and the Tres Hermanos-C Member of the Mancos Shale; and (3) the fate and transport of contaminants from the uppermost aquifer to the Westwater Canyon Member of the Morrison Formation. The data from a 1989 aquifer test were analyzed using the curve-matching software AQTESOLV and then compared with the original results. A hydrograph of the ground water elevations in monitoring wells screened in the alluvium is presented to show how the ground water elevations change with time. Stiff and Piper diagrams were created to describe the changes in ground water geochemistry in the alluvium/weathered Mancos Shale unit, the Tres Hermanos-C Sandstone unit, the Tres Hermanos-B Sandstone unit, and the Dakota Sandstone. Background information on other related topics such as site history, cell construction, soil characteristics, and well construction are presented in the SOWP. Figure 1 is a geologic cross section depicting the conceptual model of the hydrostratigraphy and ground water chemistry of the Ambrosia Lake site. Table 1 presents hydrogeologic information of each hydrostratigraphic unit.

  11. Tunnel Boring Machine Technology for a Deeply Based Missile System. Volume I, Application Feasibility. Part 1.

    Science.gov (United States)

    1980-08-01

    chart 5% Calcareous cement 5% Classification: Argillized , cherty, micaceous, calcareous felds- pathic sandstone Origin: Alluvium deposits Physical...Texture: Fine medium qrained sand with clay clasts, well sorted, argillized calcareous cementing, medium porosity and permeability Mineralogical...Composition: Quartz sand 75% Feldspathic sand 15% Clay clasts 5% Calcareous cement 5. Classification: Argillized , feldspathic w/clay clasts, calcareous

  12. A Procedure for Evaluation of Dust Potential in Desert Terrains,

    Science.gov (United States)

    1985-01-01

    ridges - ballenas . Nahal Roded, southern Arava Valley. „ ’ *m V J c^> ^ Mmmmmmmmmmmmmmmmw iu .......... . ^ ^^ - - _^^_^_m_ mm, PLATE S...the pied- mont slope in a basin. Ballena A major landform comprising distinctively round topped ridgeline rem- nants of fan alluvium. The ridge’s

  13. 76 FR 50971 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List the Leona's...

    Science.gov (United States)

    2011-08-17

    ... submission-- including any personal identifying information--will be posted on the Web site. If your... very deep alluvium derived from pumice and other volcanic rock.'' The Leona's little blue butterfly... mining, and the potential development of a biomass energy facility may have deleterious impacts on...

  14. 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.

  15. 76 FR 30002 - Establishment of the Antelope Valley of the California High Desert Viticultural Area

    Science.gov (United States)

    2011-05-24

    ... during the growing season to define climatic regions for viticulture (``General Viticulture,'' by Albert... temperature is above 50 degrees, the minimum temperature required for grapevine growth. Climatic region I has... consolidated and unconsolidated, mostly nonmarine alluvium on the valley floor. However, Oso Canyon, at...

  16. 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

  17. 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)

  18. 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.

  19. 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.

  20. Hydrogeology and ground-water quality at a land reclamation site, Neshaminy State Park, Pennsylvania

    Science.gov (United States)

    Blickwedel, Ray S.; Linn, Jeff H.

    1987-01-01

    At Neshaminy State park, the most important aquifer is the informally named 'Trenton gravel' of Pleistocene age, which consists of poorly sorted sand and gravel. This is underlain by less permeable crystalline rock that limits the downward movement of water. Up to 5 feet of Holocene (or perhaps Pleistocene) alluvium consisting of clay and silt was deposited above the Trenton gravel, but much of the surficial material is dredge spoil, mostly sand and silt from the Delaware River.

  1. Guidelines for Coding and Entering Ground-Water Data into the Ground-Water Site Inventory Data Base, Version 4.6, U.S. Geological Survey, Washington Water Science Center

    Science.gov (United States)

    2006-01-01

    where water is withdrawn should be entered as “W – Withdrawal” and Use of Water should be “E - Power Generation”. G Seismic : used solely for seismic ...anode standby emer. supply drain geo- thermal seismic heat reservoir mine obser- vation oil or gas recharge repres- surize test unused with- drawal...100GVWWO GRAVEL OF WALLA WALLA, OLDER 100PRPH PLIO-PLEISTOCENE, POST-RINGOLD-PRE- HANFORD FORMATIONS QUATERNARY 110ALVM QUATERNARY ALLUVIUM 110BSLT BASALT

  2. An Analysis of the Seismic Source Characteristics of Explosions in Low-Coupling Dry Porous Media (Postprint)

    Science.gov (United States)

    2011-12-30

    tectonic source region, explosions in dry, porous media are typically observed to have, at a given yield, mb values lower than those in hard rock by...mb/yield relation for any fixed tectonic source region, explosions in dry, porous media, such as the dry tuffs and alluvium found above the water...broadband digital data recorded from NNSS explosions at the four near-regional stations of the LLNL seismic network. Because the available data sample

  3. Estimating Yield and Depth of Burial from Rg (POSTPRINT) Annual Report 2

    Science.gov (United States)

    2012-03-20

    digital photogrammetry. 2011 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies 425 Approved for public...source surface displacements were obtained for the HUMBLE REDWOOD I explosions using digital photogrammetric techniques. We are currently in the process...explosions in alluvium and other tectonic regimes. Figure 11. Time-domain 0.5-2 Hz Rg amplitude decay with distance for 7 small explosions (< 365 lbs

  4. Managed aquifer recharge by using spreading basin methods on alluvial fans: a general overview of the situation in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Hida, N.

    2009-07-01

    In this paper, the author reviews the present situation of managed aquifer recharge (MAR) by using basin method as of 2009 in Japan. Most of the MAR basin is carried in the area of alluvial fans. The enhancing groundwater resources in the Rokugo alluvial aquifer has resulted in sustain ability for the groundwater environment, especially in the distal fan. As a recent tendency, the MAR basin contributes to sustainable aquifer management in alluvium and is spreading in Japan. (Author)

  5. Waste-to-Energy Plant Environmental Assessment, Dyess Air Force Base, Texas

    Science.gov (United States)

    2011-09-01

    2006b). Geology at Dyess AFB can be divided into two groups: the Permian Clear Fork Group and Quaternary Alluvium. The Permian Clear Fork Group...resource that cannot be restored as a result of the action (e.g., extinction of a threatened or endangered species or the disturbance of a cultural...States List of Endangered Native Fish and Wildlife or the list of fish or wildJife threatened with statewide extinction as filed by the director of

  6. A Chronostratigraphic Record of Arroyo Entrenchment and Aggradation in Kanab Creek, Southern Utah

    OpenAIRE

    Townsend, Kirk F.

    2015-01-01

    Arroyos are entrenched channels characterized by near-vertical walls of alluvium and flat channel bottoms. Historic channel entrenchment in the southwest United States during the late AD 1800s and early 1900s has stimulated extensive research on these dynamic fluvial systems. The near-synchronous episodes of arroyo entrenchment and aggradation in Kanab Creek and other drainages in southern Utah during the last ~1 Ka has led many researches to argue that hydroclimatic forcings drive arroyo p...

  7. A Cultural Resource Survey of the Offense Area of the Live Fire Maneuver Range, Fort Irwin, California.

    Science.gov (United States)

    1981-02-19

    alluvium (Smith and Ellis 1953). There is a Quaternary lake *deposit in the south-central portion of the property known variably as No Name Playa, Kitten ...projectile point, no diag- nostic artifacts were identified. A careful , comparative analy- sis of materials found at SBr-112 may aid in providing a greater...ultimately ends in the Amargosa River. A careful examination of the course of this system may provide an under- standing of the areal relationships of

  8. On the effectiveness of the vlf-em method For ground water prospecting in the Basement terrains, Sinai, Egypt

    OpenAIRE

    Shendi, El-Arabi Hendi [العربيى هندي شندي

    1997-01-01

    The VLF-EM method is proved to be an effective, fast and inexpensive tool for ground water prospecting in the basement terrains of Southern Sinai. The resistive shallow alluvial deposits increase the penetration depth of the received VLF waves to as deep as 40 meters which is very reasonable to detect the water bearing alluvium in the studied areas. The measured horizontal and vertical components of the resultant VLF-EM field were used to calculate the apparent resistivities of the conductive...

  9. Archaeological Reconnaissance in the 50 Year Flood Easement Lands. Harry S. Truman Dam and Reservoir, Missouri

    Science.gov (United States)

    1983-01-01

    Escarpment (Brezt 1965; Ward and Thompson 1977). Within the Ozark Plateaus, the channels of the Osage, South Grand, Pomme de Terre , and Sac Rivers...the Pomme de Terre River and many other tributaries of the Osage River flow from the south. The Osage River itself drains entirely into the Missouri...in all of the gravel-bearing alluvium and colluvium deposits he described along the Pomme de Terre River. The in situ chert in bluffs and secondary

  10. Archaeological Geology of the Fort Hood Military Reservation, Fort Hood, Texas

    Science.gov (United States)

    1992-06-01

    respectively. Intensive convectional rain storms commonly develop at the boundary between moist tropical air from the Gulf of Mexico and the southerly flow of...Cowhouse Creek, TR2. 20 they are typically mapped as phases of the Bosque Series (McCaleb, 1985). This is probably due in large part to the difficulty in...bedload meandering stream. The West Range alluvium is capped by soils mapped as part of the Bosque Series (McCaleb, 1985). These soils typically

  11. Comparative Demonstration of Active and Semi-Passive In Situ Bioremediation Approaches for Perchlorate-Impacted Groundwater (Longhorn Army Ammunition Plant)

    Science.gov (United States)

    2009-01-01

    subsurface geology at Site 16 consists primarily of a thin veneer of Quaternary alluvium mantling Tertiary age formations of the Wilcox and Midway Groups...APPENDIX C BOREHOLE LOGS & WELL CONSTRUCTION DETAILS 2 inch diameter schedule 40 PVC screen (0.010 inch slotted) cement surface seal drilled hole...8.5 inches in diameter portland cement with 8% bentonite 2 inch diameter well casing 20/40 filter sand 20/40 filter sand bottom screen end cap

  12. Environmental Assessment, Finding of No Significant Impact/Finding of No Practicable Alternative for Replacement of Overhead Electrical Line, Feeders K1 and K7, Vandenberg Air Force Base, California

    Science.gov (United States)

    2012-09-19

    The SCCAB is composed of the counties of San Luis Obispo, Santa Barbara, and Ventura. The SBCAPCD is responsible for regulating stationary... Rincon Shale, Vaqueros Sandstone, Gaviota- Sacate Sandstone, Cozy Dell Shale, Matilija Sandstone, Anita Shale, Espada Shale, and Honda Shale...volcanic rocks of the Tranquillon Formation, as well as Rincon Shale, Monterey Shale, and older alluvium, consisting of silt, sand, and gravel (Dibblee

  13. Final Environmental Assessment for a Solar Power System at Davis-Monthan Air Force Tucson, Arizona

    Science.gov (United States)

    2009-09-01

    deposits found in present-day drainageways, and much older deposits located on valley floors and terraces. Evidence of intense periods of volcanism can be...approximately mid-crust to 1.5 kilometers above the valley floor (University of Colorado at Boulder 2005). Most of the soils in the ROI, formed in...of mixed mineralogy, and generally formed in alluvium. Dominant soils have a thermic (mean annual soil temperature is 15 degrees Celsius [°C] or

  14. A Cultural Resources LIterature Search, Record Review and Cultural Resources Survey of the Belle Fountain Ditch Enlargement Project within Pemiscot and Dunklin Counties, Missouri

    Science.gov (United States)

    1986-06-01

    iffrentlated Alluvium braided St~ream Terrace 2 (Late wlcosinl*f) 2 braded Stroan Terraece I Figutr. 1. Projoct st-.. location PROJECT LOCATION The BFD project...Archeologist 8 (2). Anderson David G. 1976 A Preliminary Report of the Zebree Proeect: New ApDroaches in Contract Archeology in Arkansas. Assembled and...00402. Bennett, Jayne and David Higginbotham 1984 Cultural Resources Mitiaation along Ditch 19. Site 23DU227. Dunklin County, Missouri. Prepared by AR

  15. The regolith in Australia

    Science.gov (United States)

    Ollier, C. D.

    1988-12-01

    Australian regolith materials are described, many of which are complex. Much Australian regolith dates back to the Tertiary, Mesozoic or earlier. There is a progressive change in the nature of alluvium through the Tertiary. Aridity, revealed through sand dunes and evaporites, is confined to the Quaternary. Ferricretes and silcretes are formed on lower slopes, often followed by inversion of relief. Tectonic isolation of Australia as well as climatic change is responsible for the change in the nature of terrestrial sediments since the Cretaceous.

  16. Thermodynamic and hydrochemical controls on CH4 in a coal seam gas and overlying alluvial aquifer: new insights into CH4 origins

    Science.gov (United States)

    Owen, D. Des. R.; Shouakar-Stash, O.; Morgenstern, U.; Aravena, R.

    2016-08-01

    Using a comprehensive data set (dissolved CH4, δ13C-CH4, δ2H-CH4, δ13C-DIC, δ37Cl, δ2H-H2O, δ18O-H2O, Na, K, Ca, Mg, HCO3, Cl, Br, SO4, NO3 and DO), in combination with a novel application of isometric log ratios, this study describes hydrochemical and thermodynamic controls on dissolved CH4 from a coal seam gas reservoir and an alluvial aquifer in the Condamine catchment, eastern Surat/north-western Clarence-Moreton basins, Australia. δ13C-CH4 data in the gas reservoir (-58‰ to -49‰) and shallow coal measures underlying the alluvium (-80‰ to -65‰) are distinct. CO2 reduction is the dominant methanogenic pathway in all aquifers, and it is controlled by SO4 concentrations and competition for reactants such as H2. At isolated, brackish sites in the shallow coal measures and alluvium, highly depleted δ2H-CH4 (gas reservoir (200-500 m) to the shallow coal measures (<200 m) or the alluvium was not observed. The study demonstrates the importance of understanding CH4 at different depth profiles within and between aquifers. Further research, including culturing studies of microbial consortia, will improve our understanding of the occurrence of CH4 within and between aquifers in these basins.

  17. 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

  18. Tributary debris fans and the late Holocene alluvial chronology of the Colorado River, eastern Grand Canyon, Arizona

    Science.gov (United States)

    Hereford, R.; Thompson, K.S.; Burke, K.J.; Fairley, H.C.

    1996-01-01

    Bouldery debris fans and sandy alluvial terraces of the Colorado River developed contemporaneously during the late Holocene at the mouths of nine major tributaries in eastern Grand Canyon. The age of the debris fans and alluvial terraces contributes to understanding river hydraulics and to the history of human activity along the river, which has been concentrated on these surfaces for at least two to three millennia. Poorly sorted, coarse-grained debris-flow deposits of several ages are interbedded with, overlie, or are overlapped by three terrace-forming alluviums. The alluvial deposits are of three age groups: the striped alluvium, deposited from before 770 B.C. to about A.D. 300; the alluvium of Pueblo II age deposited from about A.D. 700 to 1200; and the alluvium of the upper mesquite terrace, deposited from about A.D. 1400 to 1880. Two elements define the geomorphology of a typical debris fan: the large, inactive surface of the fan and a smaller, entrenched, active debris-flow channel and fan that is about one-sixth the area of the inactive fan. The inactive fan is segmented into at least three surfaces with distinctive weathering characteristics. These surfaces are conformable with underlying debris-flow deposits that date from before 770 B.C. to around A.D. 660, A.D. 660 to before A.D. 1200, and from A.D. 1200 to slightly before 1890, respectively, based on late-19th-century photographs, radiocarbon and archaeologic dating of the three stratigraphically related alluviums, and radiocarbon dating of fine-grained debris-flow deposits. These debris flows aggraded the fans in at least three stages beginning about 2.8 ka, if not earlier in the late Holocene. Several main-stem floods eroded the margin of the segmented fans, reducing fan symmetry. The entrenched, active debris-flow channels contain deposits debris fans at the mouth of the channel adjacent to the river. Early and middle Holocene debris-flow and alluvial deposits have not been recognized, as they were

  19. 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

  20. 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

  1. 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

  2. Geologic map of the La Mesita Negra SE Quadrangle, Bernalillo County, New Mexico

    Science.gov (United States)

    Shroba, Ralph R.; Thompson, Ren A.; Schmidt, Dwight L.; Personius, Stephen F.; Maldonado, Florian; Brandt, Theodore R.

    2003-01-01

    Geologic mapping, in support of the USGS Middle Rio Grande Basin Geologic Mapping Project, shows the spatial distribution of artificial-fill, alluvial, colluvial, and eolian deposits, lava flows and related sediments of the Albuquerque volcanoes, and upper Santa Fe Group sediments. These deposits are on, beneath, and along the West Mesa (Llano de Albuquerque) just west of Albuquerque, New Mexico. Artificial fill deposits are mapped chiefly beneath and near segments of Interstate 40, in an inactive landfill (or dump) north of Interstate 40 near the eastern boundary of the map area, and in the active Cerro Colorado landfill near the southwestern corner of the map area. Alluvial deposits are mapped in stream channels, beneath treads of terraces, and on hill slopes. They include alluvium in stream channels and beneath treads of low terraces, terrace alluvium, sheetwash deposits, gravelly alluvium, and old alluvium and calcic soils of the Llano de Albuquerque. Alluvial and colluvial deposits are mapped on hill slopes. They include young alluvial-slope deposits, alluvium and colluvium, undivided, and old alluvial-slope deposits. Colluvial deposits are also mapped on hill slopes. They include colluvial deposits, undivided, as well as alluvial deposits, eolian sand, and calcic soils associated with fault scarps. Eolian deposits as well as eolian and alluvial deposits mantle gently slopping surfaces on the Llano de Albuquerque. They include active eolian sand, active and inactive eolian sand and sheetwash deposits, undivided, and inactive eolian sand and sheetwash deposits, undivided. Lava flows and related sediments of the Albuquerque volcanoes were mapped near the southeast corner of the map area. They include five young lava flows, two young cinder deposits, and old lava flows. Upper Santa Fe Group sediments are well exposed and mapped in the western part of the map area. They include a gravel unit, a pebbly sand unit, and a mud and sand unit. Undivided upper Santa Fe

  3. Pre-Shot Simulations of Far-Field Ground Motions for the Source Physics Experiment (SPE) Explosions at the Climax Stock, Nevada National Security Site

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, A J; Wagoner, J; Petersson, N A; Sjogreen, B

    2010-11-07

    The Source Physics Experiment (SPE) will involve a series of explosions in various geologic and emplacement conditions to validate numerical simulation methods to predict behavior of seismic wave excitation and propagation for nuclear test monitoring. The first SPE's currently underway involve explosions in the Climax Stock (granitic geology) at the Nevada National Security Site (NNSS). Detailed geologic data and published material properties for the major lithologic units of the NNSS and surrounding region were used to build three-dimensional models for seismic wave propagation simulations. The geologic structure near the SPE shot point is quite varied including granitic, carbonate, tuff and alluvium lithologies. We performed preliminary ground motion simulations for a near-source domain covering 8 km x 8 km at the surface centered on the shot point to investigate various source and propagation effects using WPP, LLNL's anelastic seismic wave finite difference code. Simulations indicate that variations in wave propagation properties of the sub-surface will generate strongly path-dependent response once the energy has left the relatively small granitic geology of the near-surface Climax Stock near the SPE shot point. Rough topography to the north and west of SPE shot point causes additional complexity in the signals including energy on the transverse components. Waves propagate much faster through the granitic and carbonate formations and slower through the tuff and alluvium. Synthetic seismograms for a pure explosion source in a 3D geologic structure show large amplitudes on transverse component. For paths to the south sampling the granite, tuff and alluvium lithologies transverse component amplitudes are as high as 50% of that on the vertical and radial components.

  4. 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.

  5. A complex origin for the Kelso Dunes, Mojave National Preserve, California, USA: A case study using a simple geochemical method with global applications

    Science.gov (United States)

    Muhs, Daniel R.; Lancaster, Nicholas; Skipp, Gary L.

    2017-01-01

    The Kelso Dune field in southern California is intriguing because although it is of limited areal extent ( 100 km2), it has a wide variety of dune forms and contains many active dunes ( 40 km2), which is unusual in the Mojave Desert. Studies over the past eight decades have concluded that the dunes are derived primarily from a single source, Mojave River alluvium, under a dominant, westerly-to-northwesterly wind regime. The majority of these studies did not, however, present data to support the Mojave River as the only source. We conducted mineralogical and geochemical studies of most of the 14 geomorphically defined dune groups of the Kelso Dune field as well as potential sand sources, alluvial sediments from the surrounding mountain ranges. Results indicate that sands in the nine western dune groups have K/Rb and K/Ba (primarily from K-feldspar) compositions that are indistinguishable from Mojave River alluvium (westerly/northwesterly winds) and Budweiser Wash alluvium (southwesterly winds), permitting an interpretation of two sources. In contrast, sands from the five eastern dune groups have K/Rb and K/Ba values that indicate significant inputs from alluvial fan deposits of the Providence Mountains. This requires either rare winds from the east or southeast or, more likely, aeolian reworking of distal Providence Mountain fan sediments by winds from the west, at a rate greater than input from the Mojave River or other western sources. The results indicate that even a small dune field can have a complex origin, either from seasonally varying winds or complex alluvial-fan-dune interaction. Application of K/Rb and K/Ba in K-feldspar as a provenance indicator could be used in many of the world's ergs or sand seas, where dune origins are still not well understood or are controversial. Four examples are given from Africa and the Middle East where such an approach could yield useful new information about dune sand provenance.

  6. 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.

  7. 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)

  8. 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.

  9. Comparative study of large scale simulation of underground explosions inalluvium and in fractured granite using stochastic characterization

    Science.gov (United States)

    Vorobiev, O.; Ezzedine, S. M.; Antoun, T.; Glenn, L.

    2014-12-01

    This work describes a methodology used for large scale modeling of wave propagation fromunderground explosions conducted at the Nevada Test Site (NTS) in two different geological settings:fractured granitic rock mass and in alluvium deposition. We show that the discrete nature of rockmasses as well as the spatial variability of the fabric of alluvium is very important to understand groundmotions induced by underground explosions. In order to build a credible conceptual model of thesubsurface we integrated the geological, geomechanical and geophysical characterizations conductedduring recent test at the NTS as well as historical data from the characterization during the undergroundnuclear test conducted at the NTS. Because detailed site characterization is limited, expensive and, insome instances, impossible we have numerically investigated the effects of the characterization gaps onthe overall response of the system. We performed several computational studies to identify the keyimportant geologic features specific to fractured media mainly the joints; and those specific foralluvium porous media mainly the spatial variability of geological alluvium facies characterized bytheir variances and their integral scales. We have also explored common key features to both geologicalenvironments such as saturation and topography and assess which characteristics affect the most theground motion in the near-field and in the far-field. Stochastic representation of these features based onthe field characterizations have been implemented in Geodyn and GeodynL hydrocodes. Both codeswere used to guide site characterization efforts in order to provide the essential data to the modelingcommunity. We validate our computational results by comparing the measured and computed groundmotion at various ranges. This work performed under the auspices of the U.S. Department of Energy by Lawrence LivermoreNational Laboratory under Contract DE-AC52-07NA27344.

  10. 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

  11. Isotopic and Radioactivity Fingerprinting of Groundwater in the United Arab Emirates

    DEFF Research Database (Denmark)

    Murad, A.; Aldahan, A.; Hou, Xiaolin

    2013-01-01

    a nearby alluvial plain in the southeastern part of the UAE. These two water modes are relatively easily separated by their chloride and EC (salt content) contents and provide an ideal case for testing radioactivity fingerprints. The groundwater of the alluvial plain, which is expected to reflect a short...... water types. The radioactively richer groundwater of the carbonate aquifers compared to the alluvium plane may reflect the signature of deep basinal fluids. These marked differences in radioactivity of the two water modes clearly suggests that radioactive fingerprinting can provide a potential method...

  12. Measurements of wind friction speeds over lava surfaces and assessment of sediment transport

    Science.gov (United States)

    Greeley, Ronald; Iversen, James D.

    1987-01-01

    Wind velocity profiles were obtained over alluvial plains, lava flows, and a cinder cone in the Mojave Desert to determine the wind shear and the potential for particle transport. It was found that aerodynamic roughness for winds increases nearly a factor of 5 as flow crosses from the alluvium to the lava surface, resulting in wind shear that is 21 percent greater. Thus, wind erosion and sand flux may be substantially enhanced over the lava field. Moreover, wind flow turbulence is enhanced in the wake of the cinder cone, which also increases erosion and sediment transportation by the wind.

  13. Rare earth elements in tropical surface water,soil and sediments of the Terengganu River Basin,Malaysia

    Institute of Scientific and Technical Information of China (English)

    Khawar; Sultan; Noor; Azhar; Shazili

    2009-01-01

    The 14 stable rare earth element(REE) concentrations and distribution patterns were investigated for surface waters(n=51),soils(n=52) and sediments(n=42) from the tropical Terengganu River basin,Malaysia.The chondrite normalized REE patterns of soils developed on four geological units showed enrichment of LREE,a pronounced negative Eu,and depletion of HREE with an enrichment order granite>>metasedimentary>alluvium>volcanic.The REE patterns in sediments reflected the soil REE patterns with an overall order o...

  14. Recent distribution of Sphaerium nucleus (Studer, 1820 (Bivalvia: Sphaeriidae in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Tereza Kořínková

    2008-04-01

    Full Text Available Recent data about the distribution of Sphaerium nucleus in the Czech Republic are summarized and used in an attempt to evaluate its conservation status. During the last ten years, this species was found at 40 sites, mostly shallow small water bodies situated in lowland river alluviums. These types of habitats are generally endangered due to the huge human impact and exploration of these areas. The revision of voucher specimens of Sphaerium corneum s.lat. deposited in museum collections yielded a further 22 old records of S. nucleus.

  15. An overview of experiences of basin artificial recharge of ground water in Japan

    Science.gov (United States)

    Hida, Noboru

    In this paper, the author reviews the present situation of basin artificial recharge of ground water (MAR: managed aquifer recharge) as of 2007 in Japan. Most of the artificial recharge of basin method is carried out using alluvial fans. The enhancing groundwater resources in the Rokugo alluvial aquifer has resulted in sustainability for the groundwater environment, especially in the distal fan. As a general judgment, the basin artificial recharge contributes to sustainable aquifer management in alluvium. As a result of this review, the basin artificial recharge will be utilized more in the future, not only in Japan, but in monsoon Asian countries as well.

  16. Back-Up Generator Facility and Associated Project Environmental Assessment Dyess Air Force Base, Texas

    Science.gov (United States)

    2007-07-01

    1,730 feet to approximately 1,800 feet (Dyess AFB 2004). Geology at Dyess AFB can be divided into two groups: the Permian Clear Fork Group and...Quaternary Alluvium. The Permian Clear Fork Group consists mostly of silty mudstones, thin to very thinly bedded, with some blue-gray shale near the base...restored as a result of the action (e.g., extinction of a threatened or endangered species or the disturbance of a cultural resource). 4-4

  17. Water Supply of Indian Wells Valley, California.

    Science.gov (United States)

    1986-04-01

    finite. Water pumipage and consuniptive water use exceeds (he natura rehre to the idale ’s griund-water supplN. In 1984 28.000 acre feet of’ water was...XEROPHY’TES ARTEMISiA PHREATOPHYTES SALTBRUSH PICKLEWEED WATER TABLE 𔃻A 60 ~50 SALTGRASS, ALKALI SACATONE, SAITBAUSH ~40 C-. z cc PASTURE ...limit on the amount of useful water stored in the Valley (Photo 12). MAIN GATE NWC B ONTI 2500 / MODERN ALLUVIUM "-, ~GOO’’- -0.S.5 -300 PPM _ Lu 2000

  18. Large depressions, thickened terraces, and gravitational deformation in the Ebro River valley (Zaragoza area, NE Spain): Evidence of glauberite and halite interstratal karstification

    Science.gov (United States)

    Guerrero, Jesús; Gutiérrez, Francisco; Galve, Jorge P.

    2013-08-01

    In the studied reach of the Ebro Valley, the terrace and pediment sediments deposited over glauberite- and halite-bearing evaporites show local thickenings (> 50 m) recording dissolution-induced synsedimentary subsidence. Recent data on the lithostratigraphy of the evaporite sequence allow relating the alluvium thickenings with either halite or glauberite dissolution. The alluvium-filled dissolution basin underlying the youngest terraces (T8-T11) is ascribed to halite karstification; the top of a halite unit approximately 75 m thick is situated 40-15 m below the valley bottom. The thickenings of terrace (T1-T7) and pediment sediments are attributed to interstratal glauberite karstification: (1) Coincidence between the elevation range of the terraces and that of the glauberite-rich unit. Glauberite beds reach 30 and 100 m in single-bed and cumulative thickness, respectively. (2) The exposed bedrock underlying thickened alluvium shows abundant subsidence features indicative of interstratal karstification. The most common structure corresponds to hectometer-scale sag basins with superimposed collapses in the central sector of each basin. The subsided bedrock is frequently transformed into dissolution-collapse breccias showing a complete textural gradation, from crackle packbreccias to chaotic floatbreccias and karstic residues. (3) Paleokarst exposures show evidence of karstification confined to specific beds made up of secondary gypsum after precursory glauberite, partly dissolved and partly replaced. Despite the magnitude of the subsidence recorded by the thickened alluvium and unlike nearby tributaries, the terraces show a continuous and parallel arrangement indicating that the fluvial system was able to counterbalance subsidence by aggradation. A number of kilometer-size flat-bottom depressions have been developed in the valley margin, typically next to and inset into thickened terrace and pediment deposits. The subsidence structures exposed in artificial

  19. Abandoned Well Program. Version 2.0. Volume 1

    Science.gov (United States)

    1988-09-01

    AGE: pre-1942 10 post-1942 5 DEPIH: feet Greater than 200 feet 10 100 to 200 feet 5 less than 100 feet 1 ADDIOT AL: Requested 25 Physically hazardous 10...W Section Qtr _ Qtr FIRST LEVEL FIELD SEARCH PRIORITY: Greater than 40 15 25 to 40 8 AqFE *: Denver or Arapahoe 5 Alluvium 0 ASSOCIATED CrAM2NM_... 100 % Wells Included in the Task 37 117 72 189 First level Field Search 91% 26% 46% Wells Found During the Task 37 49 26 75 First Level Field Search 42

  20. 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

  1. 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.

  2. 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.

  3. Availability and chemical characteristics of ground water in central La Plata County, Colorado

    Science.gov (United States)

    Brogden, R.E.; Giles, T.F.

    1976-01-01

    The central part of La Plata County, Colo., has undergone rapid population growth in recent years. This growth has resulted in an increased demand for information for additional domestic, industrial, and municipal water supplies. A knowledge of the occurrence of ground water will permit a more efficient allocation of the resource. Aquifers in central La Plata County include: alluvium, Animas Formation of Quaternary and Tertiary age, Fruitland Formation, Pictured Cliffs Sandstone, three formations of the Mesa Verde Group, the Mancos Shale, Dakota Sandstone, Morrison Formation of Cretaceous and Jurassic age, and undifferentiated formations. Well yields generally are low, usually less than 25 gallons per minute. However, higher yields, 25 to 50 gallons per minute may be found locally in aquifers in the alluvium and the Animas Formation. The quality of water from the aquifers is dependent on rock type. Most of the water is a calcium bicarbonate type. However, aquifers that are predominantly fine-grained or contain interbeds of shale may contain sodium bicarbonate type water. The dissolution of minerals in the coal beds, which are present in the Mesa Verde Group and the Dakota Sandstone, can contribute high concentrations of iron, sulfate, and chloride to ground water. (Woodard-USGS)

  4. 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.

  5. 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.

  6. 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.

  7. Stratigraphy and alteration, 15 shallow thermal gradient holes, Roosevelt Hot Springs KGRA and vicinity, Millard and Beaver Counties, Utah

    Energy Technology Data Exchange (ETDEWEB)

    Hulen, J.B.

    1978-09-01

    Fifteen shallow thermal gradient drill holes were recently completed by Geothermal Power Corporation (GPCR) in the vicinity of the Roosevelt Hot Springs KGRA. Five holes penetrated Tertiary granitic rocks and Precambrian gneiss east of the KGRA. Seven holes completed entirely in alluvium near the southwestern corner of the KGRA encountered a near-surface marker horizon of Pleistocene pumice and perlite. Maximum calculated alluvial sedimentation rates since initial deposition of this pumice and perlite range from 1 foot in 12,500 years to 1 foot in 2,300 years. Three holes east of the Mineral Mountains penetrated late Cenozoic basaltic andesite beneath a thin veneer of alluvium. All 15 GPCR drill holes appear to be peripheral to a central zone of anomalously high thermal gradient and low resisitivity delineated by previous investigations. GPCR-8 and -14, however, are characterized by high heat flow and relatively abundant manganese oxide mineralization, which may reflect a favorable hydrologic system controlling thermal fluid flow at depth. These holes thus seem most encouraging for discovery of a deeper high-temperature geothermal resource.

  8. 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.

  9. 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.

  10. Gravity investigations

    Energy Technology Data Exchange (ETDEWEB)

    Healey, D.L. [Geological Survey, Denver, CO (USA)

    1983-12-31

    A large density contrast exists between the Paleozoic rocks (including the rocks of Climax stock) and less dense, Tertiary volcanic rocks and alluvium. This density contrast ranges widely, and herein for interpretive purposes, is assumed to average 0.85 Mg/m{sup 3} (megagrams per cubic meter). The large density contrast makes the gravity method a useful tool with which to study the interface between these rock types. However, little or no density contrast is discernible between the sedimentary Paleozoic rocks that surround the Climax stock and the intrusive rocks of the stock itself. Therefore the gravity method can not be used to define the configuration of the stock. Gravity highs coincide with outcrops of the dense Paleozoic rocks, and gravity lows overlie less-dense Tertiary volcanic rocks and Quaternary alluvium. The positions of three major faults (Boundary, Yucca, and Butte faults) are defined by steep gravity gradients. West of the Climax stock, the Tippinip fault has juxtaposed Paleozoic rocks of similar density, and consequently, has no expression in the gravity data in that area. The gravity station spacing, across Oak Spring Butte, is not sufficient to adequately define any gravity expression of the Tippinip fault. 18 refs., 5 figs.

  11. 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.

  12. Aquifer composition and the tendency toward scale-deposit formation during reverse osmosis desalination - Examples from saline ground water in New Mexico, USA

    Science.gov (United States)

    Huff, G.F.

    2006-01-01

    Desalination is expected to make a substantial contribution to water supply in the United States by 2020. Currently, reverse osmosis is one of the most cost effective and widely used desalination technologies. The tendency to form scale deposits during reverse osmosis is an important factor in determining the suitability of input waters for use in desalination. The tendency toward scale formation of samples of saline ground water from selected geologic units in New Mexico was assessed using simulated evaporation. All saline water samples showed a strong tendency to form CaCO3 scale deposits. Saline ground water samples from the Yeso Formation and the San Andres Limestone showed relatively stronger tendencies to form CaSO4 2H2O scale deposits and relatively weaker tendencies to form SiO2(a) scale deposits than saline ground water samples from the Rio Grande alluvium. Tendencies toward scale formation in saline ground water samples from the Dockum Group were highly variable. The tendencies toward scale formation of saline waters from the Yeso Formation, San Andres Limestone, and Rio Grande alluvium appear to correlate with the mineralogical composition of the geologic units, suggesting that scale-forming tendencies are governed by aquifer composition and water-rock interaction. ?? 2006 Elsevier B.V. All rights reserved.

  13. 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.

  14. El Niño floods and culture change: A late Holocene flood history for the Rio Moquegua, southern Peru

    Science.gov (United States)

    Magilligan, Francis J.; Goldstein, Paul S.

    2001-05-01

    The 1997 1998 El Niño generated large floods throughout southern Peru, especially in inland locations along Rio Moquegua. Using remote sensing, hydraulic modeling, field surveying, and stratigraphic analyses, we estimate the magnitude and frequency of this flood and determine a late Holocene flood history for main- stem and tributary sections. Modeling indicates a peak discharge of 450 m3/s for the 1998 flood, with an estimated recurrence interval between 50 and 100 yr. Flood deposits for two large events, dated to A.D. 690 and A.D. 1300, respectively, exist in a small tributary system. Tiwanaku site abandonment (ca. A.D. 1000) predates the younger flood, indicating that stratigraphically recognizable El Niño driven floods were not a causal mechanism for abandonment. Although possessing three flood units, main-stem alluvium is considerably younger (<320 14C yr B.P.) than tributary alluvium, evidencing the major channel widening and lateral reworking of the main stem.

  15. 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.

  16. 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

    2016-11-01

    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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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

  4. Groundwater - surface water interactions in the Ayeyarwady river delta, Myanmar

    Science.gov (United States)

    Miyaoka, K.; Haruyama, S.; Kuzuha, Y.; Kay, T.

    2012-12-01

    Groundwater is widely used as a water resource in the Ayeyarwady River delta. But, Groundwater has some chemical problem in part of the area. To use safety groundwater for health, it is important to make clear the actual conditions of physical and chemical characteristics of groundwater in this delta. Besides, Ayeyarwady River delta has remarkable wet and dry season. Surface water - groundwater interaction is also different in each season, and it is concerned that physical and chemical characteristics of groundwater is affected by the flood and high waves through cyclone or monsoon. So, it is necessary to research a good aquifer distribution for sustainable groundwater resource supply. The purposes of this study are evaluate to seasonal change of groundwater - surface water interactions, and to investigate the more safety aquifer to reduce the healthy risk. Water samples are collected at 49 measurement points of river and groundwater, and are analyzed dissolved major ions and oxygen and hydro-stable isotope compositions. There are some groundwater flow systems and these water qualities are different in each depth. These showed that physical and chemical characteristics of groundwater are closely related to climatological, geomorphogical, geological and land use conditions. At the upper Alluvium, groundwater quality changes to lower concentration in wet season, so Ayeyarwady River water is main recharge water at this layer in the wet season. Besides, in the dry season, water quality is high concentration by artificial activities. Shallower groundwater is affected by land surface conditions such as the river water and land use in this layer. At lower Alluvium, Arakan and Pegu mountains are main recharge area of good water quality aquifers. Oxygen18 value showed a little affected by river water infiltration in the wet season, but keep stable good water quality through the both seasons. In the wet season, the same groundwater exists and water quality changes through

  5. Geochemical evidence for a complex origin for the Kelso dunes, Mojave National Preserve, California USA

    Science.gov (United States)

    Muhs, Daniel; Lancaster, Nicholas; Skipp, Gary L.

    2017-01-01

    The Kelso Dune field in southern California is intriguing because although it is of limited areal extent (~ 100 km2), it has a wide variety of dune forms and contains many active dunes (~ 40 km2), which is unusual in the Mojave Desert. Studies over the past eight decades have concluded that the dunes are derived primarily from a single source, Mojave River alluvium, under a dominant, westerly-to-northwesterly wind regime. The majority of these studies did not, however, present data to support the Mojave River as the only source. We conducted mineralogical and geochemical studies of most of the 14 geomorphically defined dune groups of the Kelso Dune field as well as potential sand sources, alluvial sediments from the surrounding mountain ranges. Results indicate that sands in the nine western dune groups have K/Rb and K/Ba (primarily from K-feldspar) compositions that are indistinguishable from Mojave River alluvium (westerly/northwesterly winds) and Budweiser Wash alluvium (southwesterly winds), permitting an interpretation of two sources. In contrast, sands from the five eastern dune groups have K/Rb and K/Ba values that indicate significant inputs from alluvial fan deposits of the Providence Mountains. This requires either rare winds from the east or southeast or, more likely, aeolian reworking of distal Providence Mountain fan sediments by winds from the west, at a rate greater than input from the Mojave River or other western sources. The results indicate that even a small dune field can have a complex origin, either from seasonally varying winds or complex alluvial-fan-dune interaction. Application of K/Rb and K/Ba in K-feldspar as a provenance indicator could be used in many of the world's ergs or sand seas, where dune origins are still not well understood or are controversial. Four examples are given from Africa and the Middle East where such an approach could yield useful new information about dune sand provenance.

  6. 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

  7. Morphology of calcite crystals in clast coatings from four soils in the Mojave desert region

    Science.gov (United States)

    Chadwick, Oliver A.; Sowers, Janet M.; Amundson, Ronald G.

    1989-01-01

    Pedogenic calcite-crystal coatings on clasts were examined in four soils along an altitudinal gradient on Kyle Canyon alluvium in southern Nevada. Clast coatings were studied rather than matrix carbonate to avoid the effects of soil matrix on crystallization. Six crystal sizes and shapes were recognized and distinguished. Equant micrite was the dominant crystal form with similar abundance at all elevations. The distributions of five categories of spar and microspar appear to be influenced by altitudinally induced changes in effective moisture. In the drier, lower elevation soils, crystals were equant or parallel prismatic with irregular, interlocking boundaries while in the more moist, higher elevation soils they were randomly oriented, euhedral, prismatic, and fibrous. There was little support for the supposition that Mg(+2) substitution or increased (Mg + Ca)/HCO3 ratios in the precipitating solution produced crystal elongation.

  8. Reconnaissance of ground-water resources in the Eastern Coal Field Region, Kentucky

    Science.gov (United States)

    Price, William E.; Mull, D.S.; Kilburn, Chabot

    1962-01-01

    In the Eastern Coal Field region of Kentucky, water is obtained from consolidated sedimentary rocks ranging in age from Devonian to Pennsylvanian and from unconsolidated sediments of Quaternary age. About 95 percent of the area is underlain by shale, sandstone, and coal of Pennsylvanian age. Principal factors governing the availability of water in the region are depth, topographic location, and the lithology of the aquifer penetrated. In general, the yield of the well increases as the depth increases. Wells drilled in topographic lows, such as valleys, are likely to yield more water than wells drilled on topographic highs, such as hills. Sand and gravel, present in thick beds in the alluvium along the Ohio River, form the most productive aquifer in the Eastern Coal Field. Of the consolidated rocks in the region sandstone strata are the best aquifers chiefly because joints, openings along bedding planes, and intergranular pore spaces are best developed in them. Shale also supplies water to many wells in the region, chiefly from joints and openings along bedding planes. Coal constitutes a very small part of the sedimentary section, but it yields water from fractures to many wells. Limestone yields water readily from solution cavities developed along joint and bedding-plane openings. The availability of water in different parts of the region was determined chiefly by analyzing well data collected during the reconnaissance. The resulting water-availability maps, published as hydrologic investigations atlases (Price and others, 1961 a, b; Kilburn and others, 1961) were designed to be used in conjunction with this report. The maps were constructed by dividing the region into 5 physiographic areas, into 10 subareas based chiefly on lithologic facies, and, in the case of the Kanawha section, into 2 quality-of-water areas. The 5 physiographic areas are the Knobs, Mississippian Plateau, Cumberland Plateau section, Kanawha section, and Cumberland Mountain section. The 10

  9. 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).

  10. Engineering fabrics in transportation construction

    Science.gov (United States)

    Herman, S. C.

    1983-11-01

    The following areas are discussed: treatments for reduction of reflective cracking of asphalt overlays on jointed-concrete pavements in Georgia; laboratory testing of fabric interlayers for asphalt concrete paving: interim report; reflection cracking models: review and laboratory evaluation of engineering fabrics; optimum-depth method for design of fabric-reinforced unsurfaced roads; dynamic test to predict field behavior of filter fabrics used in pavement subdrains; mechanism of geotextile performance in soil-fabric systems for drainage and erosion control; permeability tests of selected filter fabrics for use with a loess-derived alluvium; geotextile filter criteria; use of fabrics for improving the placement of till on peat foundation; geotextile earth-reinforced retaining wall tests: Glenwood Canyon, Colorado; New York State Department of Transportation's experience and guidelines for use of geotextiles; evaluation of two geotextile installations in excess of a decade old; and, long-term in situ properties of geotextiles.

  11. 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.

  12. 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.

  13. Selected fluvial monazite deposits in the southeastern United States

    Science.gov (United States)

    Overstreet, William C.; White, A.M.; Theobald, P.K.; Caldwell, D.W.

    1971-01-01

    Farther southwest in Georgia, around Griffin and Zebullon, along streams tributary to the Flint River in the monazite belt the flood plains are generally small and discontinuous, and only about 1 percent of the sediment is gravel. The area between Griffin, Zebullon, and the Flint River is underlain by biotite schist and biotite gneiss into which biotite granite has been intruded. Only along one stream, Flat Creek, which drains monazite-bearing granite near Zetella, Ga., are the tenors in monazite even moderately high, but a combination of thick, clayey overburden and discontinuous flood plains make the stream unsuitable for placer mining. Elsewhere in the Flint River area the heavy-mineral concentrates contain less than 1 percent monazite. The southwesternmost area in which reconnaissance of the monazite belt was conducted includes a groups of southwest-flowing tributaries to the Chattahoochee River north of Pine Mountain and near La Grange, Ga. A combination of three characteristics of the alluvium make the area unfavorable for mining: (1) the upper half of the sedimentary sequence is clay and silt, (2) there is scant gravel, and (3) much of the sand is fine grained. Monazite is associated with the Snelson Granite, schists, and gneisses north of the Towaliga fault, but even in this area the tenor of most riffle sediments is only 0.1 to 0.5 pound of monazite per cubic yard, and the average tenor of the alluvium is about 0.2 pound per cubic Yard. Rocks south of the Towaliga fault contain scant monazite. The monazite-bearing area in the drainage basin of the Chattahoochee River has no monazite placers. Evidence from the areas on the Flint and Chattahoochee Rivers shows that streams in western Georgia are a much poorer source of monazite than streams farther to the northeast in Georgia, South Carolina, and North Carolina. Also, the northeastern part of the belt in the drainage basins of the Yadkin and Dan Rivers is a poorer source for monazite than the area between

  14. 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.

  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. 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

  17. Mineral resource potential map of the Cohutta Wilderness and the Hemp Top Roadless Area, northern Georgia and southeastern Tennessee

    Science.gov (United States)

    Gair, Jacob E.; Gazdik, Gertrude C.; Dunn, Maynard L.

    1982-01-01

    The Cohutta Wilderness and the Hemp Top Roadless Area have minor occurrences of metallic minerals, but no known resource potential for such minerals in the forseeable future, judging by available data, and only a very minor potential for stone for aggregate, road construction, and similar nondimension use. The rocks of the Ducktown massive sulfide district to the northeast do not appear to extend into the study area, and geochemical data derived from samples of rock, soil, and alluvium do not reveal any anomalously high concentrations of trace elements that could be representative of hidden mineral deposits. Sedimentary rocks underlying the metamorphic rocks exposed at the surface have an unknown potential for hydrocarbons in the form of natural gas. No reasonable estimate of the potential can be made until some test drilling is done in the area.

  18. HISTORICAL OCCURENCE OF LIQUEFACTION IN ZAGREB AREA AND ESTIMATION OF REOCCURENCE IN CASE OF ANOTHER STRONG EARTHQUAKE

    Directory of Open Access Journals (Sweden)

    Želimir Veinović

    2007-12-01

    Full Text Available During the Great Zagreb's earthquake in 1880 consequences of the liquefaction have been detected at six sites in the vicinity of Zagreb as the occurrence of sand boils. Liquefaction takes place when loosely packed, water-logged sediments near the ground surface lose their strength in response to strong ground shaking. During the liquefaction, due to pore pressure buildup, water may be forced to the surface carrying sand particles through volcano-like sand boils. Important factor for liquefaction occurrence is the state of soil densification which relates to geological age of deposits. Results of the absolute dating of fossilized trees found in Sava's alluvium in the vicinity of Zagreb and the results of the penetration tests show that another earthquake with magnitude ≥ 6.3 can provoke liquefaction once again (the paper is published in Croatian.

  19. 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.

  20. Environmental conditions and crop density as the limiting factors of forage maize production

    Directory of Open Access Journals (Sweden)

    Dragičević Vesna D.

    2016-01-01

    Full Text Available In rain-fed cropping, defining the best combination of practices could achieve high forage yield and silage quality. The aim of this study was to compare energetic quality of produced silage with productive characteristics of forage maize cultivated on alluvium and hydromorphous black soil in rain-fed conditions at four plant densities (68-74,000 plants ha-1 during the period 2005- 2010. Yield and energy parameters were increased to some extent at higher crop densities indicating that higher densities (74,000 plants ha-1 were potentially better for high forage and DM yields, while lower densities (70,000 plants ha-1 were better for the increase of energy parameters of produced silage. [Projekat Ministarstva nauke Republike Srbije, br. TR-31037

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Pedimentation versus debris-flow origin of plateau-side desert terraces in southern Utah.

    Science.gov (United States)

    Williams, V.S.

    1984-01-01

    Plateau-side terraces in arid areas around the world are commonly described as pediment remnants, although, in many cases, they may have been formed by debris-flow deposition. Pediments do exist in the area of the Aquarius and Kaiparowits Plateaus of southern Utah; however, many alluvial terraces that were classified by previous workers as pediments are actually formed of thick deposits of sediment released into valleys by episodic landslide events. Although both pediment and debris-flow depositional terraces have smooth, alluvium-covered upper surfaces, the two can be distinguished by the shape of the underlying bedrock surface and the process of formation. The relation of younger terraces to landsliding is clear, because the terrace surfaces are graded to the toes of slide lobes, but the origin of older terraces is less obvious, because older lobes of slide debris have generally been removed by erosion. -from Author

  6. LABAN containment data report

    Energy Technology Data Exchange (ETDEWEB)

    Stubbs, T.; Heinle, R.

    1995-05-01

    The LABAN event was detonated in hole U2ff of the Nevada Test Site. The device had a depth-of-burial of 326 m in the alluvium of Area 4, about 240 m above the standing water level (SWL). Stemming of the 2.44 m diameter emplacement hole followed the plan. A log of the stemming operations was maintained by Holmes and Narver. Detonation time was 06:33 PDT on August 3, 1983. About 75 minutes later the chimney began collapsing to the surface. A major collapse event occurred 5 minutes later with episodes continuing for the next 20 minutes. No radiation arrivals were detected in the emplacement hole at depths less than 106 m and the LABAN containment was considered successful.

  7. Interpretation of geophysical data from the Colado KGRA, Pershing County, Nevada

    Science.gov (United States)

    Mackelprang, C. E.

    1982-04-01

    The Colado geothermal area is evidenced by hot water wells in alluvium along the west flank of the West Humboldt Range. The exploration of this geothermal system has progressed into advanced stages with completion of shallow thermal gradient drilling, two intermediate depth exploration drill holes, one deep exploration drill hole, detailed geologic mapping, dipole-dipole resistivity, gravity, ground magnetics. MT-AMT, TDEM and assorted uncommon electrical resisitivity techniques. A thermal anomaly was outlined by the shallow drilling. Dipole-dipole resistivity and gravity data along with detailed geologic mapping have suggested that this anomaly is structurally controlled. Other geophysical techniques employed do not appear to contribute to an understanding of the geothermal anomaly. The two intermediate depth exploration holes (IGH-1, IGH-2) and the one deep hole (44x-10) were not located in the most favorable portions of the geothermal anomaly.

  8. 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.

  9. Ground-water resources of Catron County, New Mexico

    Science.gov (United States)

    Basabilvazo, G.T.

    1997-01-01

    This report describes the occurrence, availability, and quality of ground-water and related surface-water resources in Catron County, the largest county in New Mexico. The county is located in the Lower Colorado River Basin and the Rio Grande Basin, and the Continental Divide is the boundary between the two river basins. Increases in water used for mining activities (coal, mineral, and geothermal), irrigated agriculture, reservoir construction, or domestic purposes could affect the quantity or quality of ground- water and surface-water resources in the county. Parts of seven major drainage basins are within the two regional river basins in the county--Carrizo Wash, North Plains, Rio Salado, San Agustin, Alamosa Creek, Gila, and San Francisco Basins. The San Francisco, Gila, and Tularosa Rivers typically flow perennially. During periods of low flow, most streamflow is derived from baseflow. The stream channels of the Rio Salado and Carrizo Wash Basins are commonly perennial in their upper reaches and ephemeral in their lower reaches. Largo Creek in the Carrizo Wash Basin is perennial downstream from Quemado Lake and ephemeral in the lower reaches. Aquifers in Catron County include Quaternary alluvium and bolson fill; Quaternary to Tertiary Gila Conglomerate; Tertiary Bearwallow Mountain Andesite, Datil Group, and Baca Formation; Cretaceous Mesaverde Group, Crevasse Canyon Formation, Gallup Sandstone, Mancos Shale, and Dakota Sandstone; Triassic Chinle Formation; and undifferentiated rocks of Permian age. Water in the aquifers in the county generally is unconfined; however, confined conditions may exist where the aquifers are overlain by other units of lower permeability. Yields of ground water from the Quaternary alluvium in the county range from 1 to 375 gallons per minute. Yields of ground water from the alluvium in the Carrizo Wash Basin are as much as 250 gallons per minute for short time periods. North of the Plains of San Agustin, ground-water yields from the

  10. Digital image processing applied to analysis of geophysical and geochemical data for southern Missouri

    Science.gov (United States)

    Guinness, E. A.; Arvidson, R. E.; Leff, C. E.; Edwards, M. H.; Bindschadler, D. L.

    1983-01-01

    Digital image-processing techniques have been used to analyze a variety of geophysical and geochemical map data covering southern Missouri, a region with important basement and strata-bound mineral deposits. Gravity and magnetic anomaly patterns, which have been reformatted to image displays, indicate a deep crustal structure cutting northwest-southeast through southern Missouri. In addition, geologic map data, topography, and Landsat multispectral scanner images have been used as base maps for the digital overlay of aerial gamma-ray and stream sediment chemical data for the 1 x 2-deg Rolla quadrangle. Results indicate enrichment of a variety of elements within the clay-rich alluvium covering many of the interfluvial plains, as well as a complicated pattern of enrichment for the sedimentary units close to the Precambrian rhyolites and granites of the St. Francois Mountains.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. El flujo que no cesa: aproximación a las razones, cronología y perfil de los argentinos radicados en España (1975-2001

    Directory of Open Access Journals (Sweden)

    Guillermo Mira Delli-Zotti

    2008-12-01

    Full Text Available Se estudia el fenómeno de la llegada cada vez más numerosa de argentinos a España desde la segunda mitad de la década de 1960 hasta el aluvión posterior a 1997, cuya magnitud y consecuencias aún son difíciles de evaluar. Plantea una cronología, de acuerdo a las causas de la salida, y procura indagar en los cambios que ha sufrido el perfil de los emigrantes argentinos que se dirigieron a España a lo largo de estos 40 años. Fenómeno paradójico, porque sociedad argentina fue creada por un aluvión inmigratorio, y dramático, porque los últimos arribos nos hablan de gente que abandona su tierra en respuesta a una falta total de expectativas y una situación económica insostenible, a pesar de la frecuente caracterización de Argentina como país dotado con grandes recursos naturales.________________________ABSTRACT:This article studies the phenomenon of the more and more numerous arrivals from Argentineans to Spain from second half of the decade of 1960 to the later alluvium to 1997, whose magnitude and consequences still are difficult to evaluate. It raises a chronology, according to the causes of the exit, and it tries to investigate in the changes that the profile of the Argentine emigrants has undergone who went to Spain throughout these 40 years. Paradoxical phenomenon, because Argentine society was created by an immigratory alluvium, and dramatic, because the last arrivals speak us of people who leave her earth in answer to a total lack of expectations and an untenable economic situation, in spite of the frequent characterization of Argentina like country equipped with great natural resources.

  17. 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.

  18. 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.

  19. Climatic, eustatic, and tectnoic controls on Quarternary deposits and landforms, Red Sea coast, Egypt

    Science.gov (United States)

    Arvidson, Raymond; Becker, Richard; Shanabrook, Amy; Luo, Wei; Sturchio, Neil; Sultan, Mohamed; Lofty, Zakaria; Mahmood, Abdel Moneim; El Alfy, Zeinhom

    1994-01-01

    The degree to which local climatic variations, eustatic sea level fluctuations, and tectonic uplift have influenced the development of Quaternary marine and fluvial landforms and deposits along the Red Sea coast, Eastern Desert, was investigated using a combination of remote sensing and field data, age determinations of corals, and numerical simulations. False color composites generated from Landsat Thematic Mapper and SPOT image data, digital elevation models derived from sterophotogrammetric analysis of SPOT data, and field observations document that a approximately 10-km wide swath inland from the coast is covered in many places with coalescing alluvial fans of Quaternary age. Wadis cutting through the fans exhibit several pairs of fluvial terraces, and wadi walls expose alluvium interbedded with corraline limestone deposits Further, three distinct coral terraces are evident along the coatline. Climatic, eustatic, and tectonic uplift controls on the overall system were simulated using a cellular automata algorithm with the following characteristics: (1) uplift as a function of position and time, as defined by the elevations and ages of corals; (2) climatic variations driven by insolation changes associated with Milankovitch cycles; (3) sea level fluctuations based on U/Th ages of coral terraces and eustatic data; and (4) parametrized fluvial erosion and deposition. Results imply that the fans and coralline limestones were generated in a setting in which the tectonic uplift rate decreased over the Quarternary to negligible values at present. Coralline limestones formed furing eustatic highstands when alluvium was trapped uspstream and wadis filled with debris. During lowstands, wadis cut into sedimentary deposits; coupled with continuing uplift, fans were dissected, leaving remnant surfaces, and wadi-related terraces were generated by down cutting. Only landforms from the past three to four eustatic sea level cycles (i.e., approximately 300 to 400 kyr) are likely

  20. Ground-water flow and quality near Canon City, Colorado

    Science.gov (United States)

    Hearne, G.A.; Litke, D.W.

    1987-01-01

    Water in aquifers that underlie the Lincoln Park area near Canon City, Colorado, contains measurable concentrations of chemical constituents that are similar to those in raffinate (liquid waste) produced by a nearby uranium ore processing mill. The objective of this study was to expand the existing geohydrologic data base by collecting additional geohydrologic and water quality, in order to refine the description of the geohydrologic and geochemical systems in the study area. Geohydrologic data were collected from nine tests wells drilled in the area between the U.S. Soil Conservation Service dam and Lincoln Park. Lithologic and geophysical logs of these wells indicated that the section of Vermejo Formation penetrated consisted of interbedded sandstone and shale. The sandstone beds had a small porosity and small hydraulic conductivity. Groundwater flow from the U.S. Soil Conservation Service dam to Lincoln Park seemed to be along an alluvium-filled channel in the irregular and relatively undescribed topography of the Vermejo Formation subcrop. North of the De Weese Dye Ditch, the alluvium becomes saturated and groundwater generally flows to the northeast. Water samples from 28 sites were collected and analyzed for major ions and trace elements; selected water samples also were analyzed for stable isotopes; samples were collected from wells near the uranium ore processing mill, from privately owned wells in Lincoln Park, and from the test wells drilled in the intervening area. Results from the quality assurance samples indicate that cross-contamination between samples from different wells was avoided and that the data are reliable. Water in the alluvial aquifer underlying Lincoln Park is mainly a calcium bicarbonate type. Small variations in the composition of water in the alluvial aquifer appears to result from a reaction of water leaking from the De Weese Dye Ditch with alluvial material. Upward leakage from underlying aquifers does not seem to be significant in

  1. Research on the Cause of Formation of Deep Overburden Layer of Middle Reaches of Yarkand River in Xinjiang%新疆叶尔羌河中游河段深厚覆盖层成因探讨

    Institute of Scientific and Technical Information of China (English)

    谢道在; 石豫川; 李万奎; 李振团; 王增良

    2012-01-01

    Deep overburden is one of the main engineering geological problems of water development of Middle Reaches of Yarkand River. Analyzing overburden layer formation age, material composition, development characteristics and genetic types of Dam Area is of great practical significance in project construction. Through the field survey of the Yarkand River Valley 118 km (Zangao Dam -Datong Town) and according to borehole data and geophysical test results, the overburden layer is divided into two lithological groups and three layers. Lithological group Ⅰ is the Irate Pleistocene alluvium. Lithological group Ⅱ is the Holocene alluvium. Ge netic types of deep overburden are summarized climate and glaciation, "tectonic type" aggradation, debris flow aggradation and geo graphic and geomorphic conditions.%深厚覆盖层是叶尔羌河中游河段水利开发过程中遇到的主要工程地质问题之一。分析研究该河段覆盖层的形成时代、物质组成、发育特征及成因类型对工程建设有重大的实际意义。作者通过对叶尔羌河流域118km(錾高坝址一大同乡)的实地调查并根据钻孔资料和物探测试成果,将中游段的覆盖层分为两大岩性组(Ⅰ岩性组(Q3^al)、Ⅱ岩性组(Qi3^al))三大层。且将深厚覆盖层成因类型归纳为气候和冰川作用、“构造型”加积、泥石流加积作用及地形地貌4种。

  2. Storage and mobilization of natural and septic nitrate in thick unsaturated zones, California

    Science.gov (United States)

    Izbicki, John A.; Flint, Alan L.; O'Leary, David R.; Nishikawa, Tracy; Martin, Peter; Johnson, Russell D.; Clark, Dennis A.

    2015-01-01

    Mobilization of natural and septic nitrate from the unsaturated zone as a result of managed aquifer recharge has degraded water quality from public-supply wells near Yucca Valley in the western Mojave Desert, California. The effect of nitrate storage and potential for denitrification in the unsaturated zone to mitigate increasing nitrate concentrations were investigated. Storage of water extractable nitrate in unsaturated alluvium up to 160 meters (m) thick, ranged from 420 to 6600 kilograms per hectare (kg/ha) as nitrogen (N) beneath undeveloped sites, from 6100 to 9200 kg/ha as N beneath unsewered sites. Nitrate reducing and denitrifying bacteria were less abundant under undeveloped sites and more abundant under unsewered sites; however, δ15N–NO3, and δ18O–NO3 data show only about 5–10% denitrification of septic nitrate in most samples—although as much as 40% denitrification occurred in some parts the unsaturated zone and near the top of the water table. Storage of nitrate in thick unsaturated zones and dilution with low-nitrate groundwater are the primary attenuation mechanisms for nitrate from septic discharges in the study area. Numerical simulations of unsaturated flow, using the computer program TOUGH2, showed septic effluent movement through the unsaturated zone increased as the number and density of the septic tanks increased, and decreased with increased layering, and increased slope of layers, within the unsaturated zone. Managing housing density can delay arrival of septic discharges at the water table, especially in layered unsaturated alluvium, allowing time for development of strategies to address future water-quality issues.

  3. 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.

  4. 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.

  5. Seismic Hazard Maps for Seattle, Washington, Incorporating 3D Sedimentary Basin Effects, Nonlinear Site Response, and Rupture Directivity

    Science.gov (United States)

    Frankel, Arthur D.; Stephenson, William J.; Carver, David L.; Williams, Robert A.; Odum, Jack K.; Rhea, Susan

    2007-01-01

    This report presents probabilistic seismic hazard maps for Seattle, Washington, based on over 500 3D simulations of ground motions from scenario earthquakes. These maps include 3D sedimentary basin effects and rupture directivity. Nonlinear site response for soft-soil sites of fill and alluvium was also applied in the maps. The report describes the methodology for incorporating source and site dependent amplification factors into a probabilistic seismic hazard calculation. 3D simulations were conducted for the various earthquake sources that can affect Seattle: Seattle fault zone, Cascadia subduction zone, South Whidbey Island fault, and background shallow and deep earthquakes. The maps presented in this document used essentially the same set of faults and distributed-earthquake sources as in the 2002 national seismic hazard maps. The 3D velocity model utilized in the simulations was validated by modeling the amplitudes and waveforms of observed seismograms from five earthquakes in the region, including the 2001 M6.8 Nisqually earthquake. The probabilistic seismic hazard maps presented here depict 1 Hz response spectral accelerations with 10%, 5%, and 2% probabilities of exceedance in 50 years. The maps are based on determinations of seismic hazard for 7236 sites with a spacing of 280 m. The maps show that the most hazardous locations for this frequency band (around 1 Hz) are soft-soil sites (fill and alluvium) within the Seattle basin and along the inferred trace of the frontal fault of the Seattle fault zone. The next highest hazard is typically found for soft-soil sites in the Duwamish Valley south of the Seattle basin. In general, stiff-soil sites in the Seattle basin exhibit higher hazard than stiff-soil sites outside the basin. Sites with shallow bedrock outside the Seattle basin have the lowest estimated hazard for this frequency band.

  6. Manganese minerals and associated fine particulates in the streambed of Pinal Creek, Arizona, U.S.A.: a mining-related acid drainage problem

    Science.gov (United States)

    Lind, Carol J.; Hem, J.D.

    1993-01-01

    The Pinal creek drainage basin in Arizona is a good example of the principal non-coal source of mining-related acid drainage in the U.S.A., namely copper mining. Infiltration of drainage waters from mining and ore refining has created an acid groundwater plume that has reacted with calcite during passage through the alluvium, thereby becoming less acid. Where O2 is present and the water is partially neutralized, iron oxides have precipitated and, farther downstream where the pH of the stream water is near neutral, high-Mn crusts have developed. Trace metal composition of several phases in the Pinal Creek drainage basin illustrates the changes caused by mining activities and the significant control Mn-crusts and iron oxide deposits exert on the distribution and concentration of trace metals. The phases and locales considered are the dissolved phase of Webster Lake, a former acid waste disposal pond; selected sections of cores drilled in the alluvium within the intermittent reach of Pinal Creek; and the dissolved phase, suspended sediments, and streambed deposits at specified locales along the perennial reach of Pinal creek. In the perennial reach of Pinal Creek, manganese oxides precipitate from the streamflow as non-cemented particulates and coatings of streambed material and as cemented black crusts. Chemical and X-ray diffraction analyses indicate that the non-cemented manganese oxides precipitate in the reaction sequence observed in previous laboratory experiments using simpler solution composition, Mn3O4 to MnOOH to an oxide of higher oxidation number usually silicates. ?? 1992.

  7. 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''.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Quaternary stratigraphy, geochronology and evolution of the Magela Creek catchment in the monsoon tropics of northern Australia

    Science.gov (United States)

    Nanson, Gerald C.; East, T. Jon; Roberts, Richard G.

    1993-03-01

    Magela Creek, a major tributary of the East Alligator River in northern Australia, has left a detailed sedimentary record of a fluvial landscape dominated by climatic and eustatic changes associated with Quaternary glacial-interglacial cycles. Uranium-series dates from young pisoliths in floodplain deposits indicate that ferruginisation is probably ongoing under present conditions while ferricretes in degraded terraces that flank the lower valley reveal a fluvial history extending back to early Pleistocene or Tertiary time. Inset within this older alluvium is a valley fill which, from thermoluminescence dates, was initiated about 300 kyr ago. With each glacial climate change and associated fall in sea level, distinct palaeochannels have been eroded into these floodplains, infilling later with alluvium when climate and base-level conditions were conducive to fluvial deposition. Radiocarbon dates show that the most recent palaeochannel beneath the modern Magela Creek last started to fill by downstream progradation and vertical accretion of bedload sand about 8 kyr. The palaeochannel filled at an accelerating rate, probably as a result of declining stream competence associated with drier conditions in the late Holocene augmented by the backwater effects of sea-level rise. Continued aggradation blocked the mouths of tributary valleys along Magela Creek, forming alluvial-dammed tributary lakes and deferred-junction tributary streams. From about 300 kyr, cyclic episodes of channel incision and sediment evacuation in this tropical-monsoon river valley have become less effective, possibly because increasing aridity in the late Quaternary has reduced the erosional effectiveness of Australia's northern rivers. Reduced flow regime and rising sea level in the late Holocene has resulted in the latest phase of alluvial accretion.

  13. 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

  14. Availability of ground water in parts of the Acoma and Laguna Indian Reservations, New Mexico

    Science.gov (United States)

    Dinwiddie, George A.; Motts, Ward Sundt

    1964-01-01

    The need for additional water has increased in recent years on the Acoma and Laguna Indian Reservations in west-central New Mexico because the population and per capita use of water have increased; the tribes also desire water for light industry, for more modern schools, and to increase their irrigation program. Many wells have been drilled in the area, but most have been disappointing because of small yields and poor chemical quality of the water. The topography in the Acoma and Laguna Indian Reservations is controlled primarily by the regional and local dip of alternating beds of sandstone and shale and by the igneous complex of Mount Taylor. The entrenched alluvial valley along the Rio San Jose, which traverses the area, ranges in width from about 0.4 mile to about 2 miles. The climate is characterized by scant rainfall, which occurs mainly in summer, low relative humidity, and large daily fluctuations of temperature. Most of the surface water enters the area through the Rio San Jose. The average annual streamflow past the gaging station Rio San Jose near Grants, N. Mex. is about 4,000 acre-feet. Tributaries to the Rio San Jose within the area probably contribute about 1,000 acre-feet per year. At the present time, most of the surface water is used for irrigation. Ground water is obtained from consolidated sedimentary rocks that range in age from Triassic to Cretaceous, and from unconsolidated alluvium of Quaternary age. The principal aquifers are the Dakota Sandstone, the Tres Hermanos Sandstone Member of the Mancos Shale, and the alluvium. The Dakota Sandstone yields 5 to 50 gpm (gallons per minute) of water to domestic and stock wells. The Tres Hermanos sandstone Member generally yields 5 to 20 gpm of water to domestic and stock wells. Locally, beds of sandstone in the Chinle and Morrison Formations, the Entrada Sandstone, and the Bluff Sandstone also yield small supplies of water to domestic and stock wells. The alluvium yields from 2 gpm to as much as 150

  15. 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

  16. Surficial Geologic Map of the Evansville, Indiana, and Henderson, Kentucky, Area

    Science.gov (United States)

    Moore, David W.; Lundstrom, Scott C.; Counts, Ronald C.; Martin, Steven L.; Andrews, William M.; Newell, Wayne L.; Murphy, Michael L.; Thompson, Mark F.; Taylor, Emily M.; Kvale, Erik P.; Brandt, Theodore R.

    2009-01-01

    The geologic map of the Evansville, Indiana, and Henderson, Kentucky, area depicts and describes surficial deposits according to their origin and age. Unconsolidated alluvium and outwash fill the Ohio River bedrock valley and attain maximum thickness of 33-39 m under Diamond Island, Kentucky, and Griffith Slough, south of Newburgh, Indiana. The fill is chiefly unconsolidated, fine- to medium-grained, lithic quartz sand, interbedded with clay, clayey silt, silt, coarse sand, granules, and gravel. Generally, the valley fill fines upward from the buried bedrock surface: a lower part being gravelly sand to sandy gravel, a middle part mostly of sand, and a surficial veneer of silt and clay interspersed with sandy, natural levee deposits at river's edge. Beneath the unconsolidated fill are buried and discontinuous, lesser amounts of consolidated fill unconformably overlying the buried bedrock surface. Most of the glaciofluvial valley fill accumulated during the Wisconsin Episode (late Pleistocene). Other units depicted on the map include creek alluvium, slackwater lake (lacustrine) deposits, colluvium, dune sand, loess, and sparse bedrock outcrops. Creek alluvium underlies creek floodplains and consists of silt, clayey silt, and subordinate interbedded fine sand, granules, and pebbles. Lenses and beds of clay are present locally. Silty and clayey slackwater lake (lacustrine) deposits extensively underlie broad flats northeast of Evansville and around Henderson and are as thick as 28 m. Fossil wood collected from an auger hole in the lake and alluvial deposits of Little Creek, at depths of 10.6 m and 6.4 m, are dated 16,650+-50 and 11,120+-40 radiocarbon years, respectively. Fossil wood collected from lake sediment 16 m below the surface in lake sediment was dated 33,100+-590 radiocarbon years. Covering the hilly bedrock upland is loess (Qel), 3-7.5 m thick in Indiana and 9-15 m thick in Kentucky, deposited about 22,000-12,000 years before present. Most mapped surficial

  17. 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

  18. Pliocene and Quaternary Deposits in the Northern Part of the San Juan Basin in Southwestern Colorado and Northwestern New Mexico

    Science.gov (United States)

    Scott, Glenn R.; Moore, David W.

    2007-01-01

    Unconsolidated late Cenozoic deposits in the northern part of the San Juan Basin range in age from late Pliocene to Holocene. Most of the deposits are alluvial gravel composed of resistant quartzite, sandstone, and igneous, metamorphic, and volcanic rocks derived from the uplifted central core of the San Juan Mountains 20-50 miles (32-80 kilometers) north of the basin. Alluvial deposits are most voluminous in the Animas Valley, but deposits of gravel of the same general age are present in the La Plata, Florida, Los Pinos, and Piedra River valleys as well. Alluvial gravel forms tabular deposits, generally about 20 feet (6 meters) thick, that are exposed beneath a sequence of terraces at many levels above the rivers. Gravel layers 360 feet (110 meters) or less above the Animas River are glacial outwash. The gravel layers begin at the south toes of end moraines and extend discontinuously downvalley at least 10-20 miles (16-32 kilometers). Farther south, distinction between outwash and nonglacial alluvium is problematical. Alluvial gravel beneath higher terraces does not grade to end moraines. Glacial till forms a series of end moraines at the north edge of the town of Durango. The oldest moraines are farthest downvalley, are higher above the river, and have more mature surficial soils than do moraines farther north. The two youngest moraines, the Animas City moraines, are interpreted to be Pinedale in age. They have narrow, ridgelike crests and form nearly unbroken arcs across the valley floor. Small segments of still more weathered moraines, the Spring Creek moraines, are 170-230 feet (52-70 meters) above the river and are 660-990 feet (200-300 meters) farther downvalley. The oldest moraines, the Durango moraines, are on the north end of the unnamed mesa on which Fort Lewis College is located. The base is about 180 feet (55 meters) above the river. These oldest moraines may be of Bull Lake age. Alluvial fans, pediment gravel, and landslides are scattered at several

  19. An investigation into variable recharge behaviors among eight alluvial observation wells in Pajarito Canyon, Los Alamos, New Mexico

    Science.gov (United States)

    Schmeer, S. R.

    2010-12-01

    Pajarito Canyon in Los Alamos, New Mexico trends west to east through the Pajarito Plateau from the headwaters in the Jemez Mountains, thirteen miles to the Rio Grande. In summer 2008, Los Alamos National Laboratory installed eight shallow wells, numbered PCAO-5, 6, 7a, 7b1, 7b2, 7c, 8 and 9, in the middle four miles of this canyon. Among these wells, five distinct recharge behaviors have been observed. PCAO-5 demonstrates seasonal recharge in response to annual snowmelt. PCAO-6, while just 400 feet further downstream, is considerably flashier and the well is often dry for months at a time. In PCAO-7a, 7b2 and 7c, another two miles downstream, the water level declined steadily since installation, with no recharge until spring 2010. PCAO-7b1 has not contained water since drilling. Downstream a further two miles, PCAO-8 and PCAO-9 were dry for the majority of 2009 and their hydrographs are more attenuated. This investigation was undertaken to explain the recharge behaviors of the wells, with the goal of improving site selection and design of alluvial wells to provide better representation of the alluvial aquifer. Water level data collected since July 2008 were used to compare the water columns of each well. Well construction diagrams were utilized to construct stratigraphic maps in order to compare well construction and lithology. Results indicate that PCAO-5 consistently contains water due to its location above a flood retention structure (FRS) and the placement of its screened interval immediately above the tuff layer, forcing water to travel through the screened interval. PCAO-6’s flashy, intermittent hydrograph is due to its location downstream of the FRS, and because the bottom of the screened interval rests 2.5 feet above the alluvium-tuff interface, providing a conduit below the screen of the well. The similar behaviors of PCAO-7a, 7b2 and 7c result from their near-identical construction, lithology and location. The general decline of water level until

  20. 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

  1. 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

  2. Using seismic reflection to locate a tracer testing complex south of Yucca Mountain, Nye County, Nevada

    Science.gov (United States)

    Kryder, Levi

    Tracer testing in the fractured volcanic aquifer near Yucca Mountain, and in the alluvial aquifer south of Yucca Mountain, Nevada has been conducted in the past to determine the flow and transport properties of groundwater in those geologic units. However, no tracer testing has been conducted across the alluvium/volcanic interface. This thesis documents the investigative process and subsequent analysis and interpretations used to identify a location suitable for installation of a tracer testing complex, near existing Nye County wells south of Yucca Mountain. The work involved evaluation of existing geologic data, collection of wellbore seismic data, and a detailed surface seismic reflection survey. Borehole seismic data yielded useful information on alluvial P-wave velocities. Seismic reflection data were collected over a line of 4.5-km length, with a 10-m receiver and shot spacing. Reflection data were extensively processed to image the alluvium/volcanic interface. A location for installation of an alluvial/volcanic tracer testing complex was identified based on one of the reflectors imaged in the reflection survey; this site is located between existing Nye County monitoring wells, near an outcrop of Paintbrush Tuff. Noise in the reflection data (due to some combination of seismic source signal attenuation, poor receiver-to-ground coupling, and anthropogenic sources) were sources of error that affected the final processed data set. In addition, in some areas low impedance contrast between geologic units caused an absence of reflections in the data, complicating the processing and interpretation. Forward seismic modeling was conducted using Seismic Un*x; however, geometry considerations prevented direct comparison of the modeled and processed data sets. Recommendations for additional work to address uncertainties identified during the course of this thesis work include: drilling additional boreholes to collect borehole seismic and geologic data; reprocessing a

  3. Soil nutrients affect spatial patterns of aboveground biomass and emergent tree density in southwestern Borneo.

    Science.gov (United States)

    Paoli, Gary D; Curran, Lisa M; Slik, J W F

    2008-03-01

    Studies on the relationship between soil fertility and aboveground biomass in lowland tropical forests have yielded conflicting results, reporting positive, negative and no effect of soil nutrients on aboveground biomass. Here, we quantify the impact of soil variation on the stand structure of mature Bornean forest throughout a lowland watershed (8-196 m a.s.l.) with uniform climate and heterogeneous soils. Categorical and bivariate methods were used to quantify the effects of (1) parent material differing in nutrient content (alluvium > sedimentary > granite) and (2) 27 soil parameters on tree density, size distribution, basal area and aboveground biomass. Trees > or =10 cm (diameter at breast height, dbh) were enumerated in 30 (0.16 ha) plots (sample area = 4.8 ha). Six soil samples (0-20 cm) per plot were analyzed for physiochemical properties. Aboveground biomass was estimated using allometric equations. Across all plots, stem density averaged 521 +/- 13 stems ha(-1), basal area 39.6 +/- 1.4 m(2) ha(-1) and aboveground biomass 518 +/- 28 Mg ha(-1) (mean +/- SE). Adjusted forest-wide aboveground biomass to account for apparent overestimation of large tree density (based on 69 0.3-ha transects; sample area = 20.7 ha) was 430 +/- 25 Mg ha(-1). Stand structure did not vary significantly among substrates, but it did show a clear trend toward larger stature on nutrient-rich alluvium, with a higher density and larger maximum size of emergent trees. Across all plots, surface soil phosphorus (P), potassium, magnesium and percentage sand content were significantly related to stem density and/or aboveground biomass (R (Pearson) = 0.368-0.416). In multiple linear regression, extractable P and percentage sand combined explained 31% of the aboveground biomass variance. Regression analyses on size classes showed that the abundance of emergent trees >120 cm dbh was positively related to soil P and exchangeable bases, whereas trees 60-90 cm dbh were negatively related to these

  4. Investigation of the geologic and tectonic structures of Bafa Lake and Akbuk Gulf (terrestrial and marine areas) by means of gravity and magnetic methods

    Science.gov (United States)

    Edremit, Şüheda; Özel, Erdeniz

    2016-04-01

    Geologic units of Bafa Lake and Akbuk Gulf, which have very importance in point of geologic and tectonic structure, are generally are classified by high-grade metamorphic units of the Menderes Core Complex, Cycladic Complex (schist, marble, eclogite), Afyon zone meta sedimentary and Pan-African basement rocks, Neogene volcanic-sedimentary rocks and alluvium. As for tectonic structures of study areas are; Izmir-Balikesir Transfer Zone also affected the Buyuk Menderes Graben, Bornova Flysch Zone, Menderes Massif and Lycian Nappes. Regional researches were studied to reveal using Turkey Bouguer Anomaly and Turkey Aeromagnetic regional map with gravity method used for geologic structures analysis and magnetic method used to explain main structure, tectonic conditions of underground. General geologic structure and tectonic lineaments of region were examined and interpretated compatibility with gravity and magnetic values. When the geologic and tectonic structures on the terrestrial areas are generally investigated, graben systems and linearities are clearly seen on the Bouguer Anomaly map. Positive values are seen in the Bornova Flysch Zone and Menderes Massif areas at the north of study areas arising from high-density ophiolitic and metamorphic units. Graben areas in the Menderes Massif are observed negative gravity values on the low-density young alluviums. Positive gravity values are increased up to 50-60 mgal on the metamorphic rocks that are named Cycladic Complex located southwest of study areas. At the aeromagnetic regional magnetic map, gamma values about -100 observed on the Menderes Massif region are indicated metagranite rocks that are Paleozoic crystalline structure. Gamma values, which are changed between -100 and +100 at the transition areas granite with schists, are obviously revealed this transition region. Located northwest of study areas Upper Miocene-Pliocene aged from sedimentary rocks on the terrestrial carbonates and nonsegregated terrestrial

  5. High Resolution Digital Elevation Models of Pristine Explosion Craters

    Science.gov (United States)

    Farr, T. G.; Krabill, W.; Garvin, J. B.

    2004-01-01

    In order to effectively capture a realistic terrain applicable to studies of cratering processes and landing hazards on Mars, we have obtained high resolution digital elevation models of several pristine explosion craters at the Nevada Test Site. We used the Airborne Terrain Mapper (ATM), operated by NASA's Wallops Flight Facility to obtain DEMs with 1 m spacing and 10 cm vertical errors of 4 main craters and many other craters and collapse pits. The main craters that were mapped are Sedan, Scooter, Schooner, and Danny Boy. The 370 m diameter Sedan crater, located on Yucca Flat, is the largest and freshest explosion crater on Earth that was formed under conditions similar to hypervelocity impact cratering. As such, it is effectively pristine, having been formed in 1962 as a result of a controlled detonation of a 100 kiloton thermonuclear device, buried at the appropriate equivalent depth of burst required to make a simple crater. Sedan was formed in alluvium of mixed lithology and subsequently studied using a variety of field-based methods. Nearby secondary craters were also formed at the time and were also mapped by ATM. Adjacent to Sedan and also in alluvium is Scooter, about 90 m in diameter and formed by a high-explosive event. Schooner (240 m) and Danny Boy (80 m) craters were also important targets for ATM as they were excavated in hard basalt and therefore have much rougher ejecta. This will allow study of ejecta patterns in hard rock as well as engineering tests of crater and rock avoidance and rover trafficability. In addition to the high resolution DEMs, crater geometric characteristics, RMS roughness maps, and other higher-order derived data products will be generated using these data. These will provide constraints for models of landing hazards on Mars and for rover trafficability. Other planned studies will include ejecta size-frequency distribution at the resolution of the DEM and at finer resolution through air photography and field measurements

  6. 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

  7. 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

  8. Organic Carbon Inventories and Vertical Fluxes Through the Vadose Zone into Groundwater at the Rifle, Colorado River Floodplain Site

    Science.gov (United States)

    Tokunaga, T. K.; Wan, J.; Dong, W.; Williams, K. H.; Robbins, M.; Kim, Y.; Faybishenko, B.; Conrad, M. E.; Christensen, J. N.; Gilbert, B.; Dayvault, R. D.; Long, P. E.; Hubbard, S. S.

    2013-12-01

    Understanding carbon inventories and fluxes within the vadose zone and groundwater of semi-arid regions is challenging because of their typically deep profiles, moderately low soil organic carbon (SOC) inventories, low dissolved organic carbon (DOC) fluxes, and slow changes in soil inorganic carbon (SIC) inventories. The remediated uranium/vanadium mill tailings site situated on a floodplain at Rifle, Colorado possesses a number of characteristics that facilitate investigation of subsurface carbon fluxes. These include locally derived fill soil having SOC and SIC concentrations representative of the region, established vegetation cover (perennial grasses and shrubs) on the fill, boundaries between the fill and underlying alluvium distinguishable through concentrations of SIC and other chemical components, predictable groundwater flow and interaction with the adjacent Colorado River, and a clearly delineated impermeable lower boundary (Wasatch Formation shale) at depths ranging from 6 to 7.5 m. Environmental characteristics of this site permit year-round sampling of both pore water and pore gas throughout most of the moderately deep (~ 3.5 m) vadose zone. Within this well-defined hydrological system, we recently installed a suite of tensiometers, pore water (vadose zone and groundwater) samplers, gas samplers, and neutron probe access tubes at three sites along a transect aligned with the groundwater flow direction in order to determine inventories and fluxes of water, carbon, and other components. The tensiometer and piezometer measurements are revealing impacts of infiltration and groundwater recharge events, evapotranspiration, and capillary fringe-groundwater interactions. The results of pore water analyses are showing relatively high concentrations of DOC (up to 4 mM) in the vadose zone, and particulate organic carbon (POC) mobile in the capillary fringe. Differences in DOC characteristics are being determined using a variety of analytical techniques. Hydraulic

  9. Reconnaissance of the geology and ground-water hydrology of the Belle Fourche irrigation project, South Dakota

    Science.gov (United States)

    Rosier, Arthur J.

    1952-01-01

    The Belle Fourche irrigation project is in western South Dakota on the plains adjacent to the northeastern edge of the Black Hills. The project is drained by the Belle Fourche River and is characterized generally by broad shallow valleys that lie between hills with gentle slopes. The climate is semiarid. Most of the area is mantled by residual clay, terrace deposits, and alluvium. The terrace deposits contain much water and are the most permeable deposits in the project area. The alluvial deposits of the Belle Fourche River and of the creeks south of the river contain much sand and gravel and are relatively permeable. The alluvium of the creeks north of the river is predominantly clay and is only slightly permeable; it greatly resembles the residual clay of the weathered bedrock formations, which are mostly shale in this area. Although relatively abundant ground water is found in the unconsolidated materials above the bedrock formations, the ground water from the clayey deposits generally contains too great a concentration of objectionable salts to be fit for human or livestock consumption. The ground water in the more coarse materials is of better quality and in some small areas is satisfactory for domestic use. Most of the water for domestic use is hauled from deep artesian wells within the area. The chief source of ground water is seepage from irrigation canals in the terrace and alluvial deposits. When this water moves to areas of lower permeability a correspondingly greater rise of the water table compensates for the lower permeability and results in the waterlogging of many areas. Open drainage ditches have been constructed in all large areas that are affected by high ground-water levels. Except in those areas that are underlain predominantly by clayey materials, these ditches usually have proven to be satisfactory for the control of ground-water levels. However, lining the canals seems to be a more satisfactory method of preventing the seepage that causes

  10. Surficial Geologic Map of Mesa Verde National Park, Montezuma County, Colorado

    Science.gov (United States)

    Carrara, Paul E.

    2012-01-01

    Mesa Verde National Park in southwestern Colorado was established in 1906 to preserve and protect the artifacts and dwelling sites, including the famous cliff dwellings, of the Ancestral Puebloan people who lived in the area from about A.D. 550 to A.D. 1300. In 1978, the United Nations designated the park as a World Heritage Site. The geology of the park played a key role in the lives of these ancient people. For example, the numerous (approximately 600) cliff dwellings are closely associated with the Cliff House Sandstone of Late Cretaceous age, which weathers to form deep alcoves. In addition, the ancient people farmed the thick, red loess (wind-blown dust) deposits on the mesa tops, which because of its particle size distribution has good moisture retention properties. The soil in this loess cover and the seasonal rains allowed these people to grow their crops (corn, beans, and squash) on the broad mesa tops. Today, geology is still an important concern in the Mesa Verde area because the landscape is susceptible to various forms of mass movement (landslides, debris flows, rockfalls), swelling soils, and flash floods that affect the park's archeological sites and its infrastructure (roads, septic systems, utilities, and building sites). The map, which encompasses an area of about 100 mi2 (260 km2), includes all of Mesa Verde National Park, a small part of the Ute Mountain Indian Reservation that borders the park on its southern and western sides, and some Bureau of Land Management and privately owned land to the north and east. Surficial deposits depicted on the map include: artificial fills, alluvium of small ephemeral streams, alluvium deposited by the Mancos River, residual gravel on high mesas, a combination of alluvial and colluvial deposits, fan deposits, colluvial deposits derived from the Menefee Formation, colluvial deposits derived from the Mancos Shale, rockfall deposits, debris flow deposits, earthflow deposits, translational and rotational landslide

  11. Characteristic ground motions of the 25th April 2015 Nepal earthquake (Mw 7.9) and its implications for the structural design codes for the border areas of India to Nepal

    Science.gov (United States)

    Sharma, Babita; Chingtham, Prasanta; Sharma, Varun; Kumar, Vikas; Mandal, H. S.; Mishra, O. P.

    2017-01-01

    The 25th April 2015 Nepal Earthquake was found associated with a series of aftershocks, and the mainshock rupture propagated predominantly towards SE direction where a major aftershock (Mw 7.3) rocked on 12th May 2015 to the east of the mainshock that enhanced the rate of occurrence of aftershocks in the affected region. We conducted a rigorous analysis of strong motion data to understand the characteristics of ground motion and their bearing on the structural design codes, responsible for the damage to the structures in the border area of India to Nepal. The effect of ground geology on the acceleration response spectra are also evaluated using main shock and its associated strong earthquakes. All the sites used in the present analysis are located on alluvium deposits showing a predominant period of 0.242 sec for horizontal components and at 0.193 sec for vertical components. Our results demonstrated that observed Peak Ground Acceleration (PGA) has prominent distribution in the border cities of UP and Bihar. PGA ranges from 3 to 80 cm/sec2 in the study region for the epicentral distance varying from 120 km to 495 km with respect to the source zone (mainshock). The Peak Ground Velocity (PGV) varies from 1 to 16 cm/sec while the Peak Ground Displacement (PGD) lies in between 1 cm and 20 cm for the same area. Our study shows that variation of PGD, PGV, and PGA are controlled and dictated by the geo-morphological constraints, besides the nature and extent of structural heterogeneities of the sub-surface geological formation materials. The obtained normalised spectral amplifications are compared with the Bureau of Indian Standard code for construction of buildings which shows that the current Indian building design code is within the structural limits proposed for the seismic forces at all periods for alluvium sites, suggesting that the structural heterogeneity has the strong role contributing towards the intrinsic attenuation in the seismic wave propagating medium. Our

  12. 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

  13. 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

  14. 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

  15. Terrace Geochemistry at the Shiprock, New Mexico, Disposal Site - WM2017-17232 Initial Phase

    Energy Technology Data Exchange (ETDEWEB)

    Kautsky, Mark [USDOE Office of Legacy Management, Washington, DC (United States); Ranalli, Tony [Navarro Research and Engineering, Oak Ridge, TN (United States); Dander, David [Navarro Research and Engineering, Oak Ridge, TN (United States); Miller, David [Navarro Research and Engineering, Oak Ridge, TN (United States)

    2017-03-08

    The objective of this investigation was to identify and differentiate potential non- mill-related water inputs to a shallow terrace groundwater system through the use of aqueous chemical and isotopic tracers at a former uranium- and vanadium-ore processing facility. Terrace groundwater in the vicinity of the Shiprock, New Mexico, site is hypothesized to be largely anthropogenic because natural rates of recharge in the terrace are likely insufficient to sustain a continuous water table in the terrace alluvial system, as observed in several analogue terrace locations east of the site and in response to post-mill dewatering efforts across the site. The terrace is composed of alluvial sand and gravel and weathered and unweathered Mancos Shale. Terrace groundwater exists and flows in the alluvium and to a much less extent in the Mancos Shale. Historical data established that in both the terrace and floodplain below the terrace, mill-derived uranium and sulfate is found primarily in the alluvium and the upper portion of the weathered Mancos Shale. Groundwater extraction is being conducted in the vicinity of former mill operations and in washes and seeps to dewater the formation and remove contamination, thus eliminating these exposure pathways and minimizing movement to the floodplain. However, past and present contribution of non-mill anthropogenic water sources may be hindering the dewatering effort, resulting in reduced remedy effectiveness. Groundwater source signatures can be determined based on chemical and isotopic ratios and are used to help identify and delineate both mill and non-mill water contributions. Aqueous chemical and isotopic tracers, such as 234U/238U activity ratios and uranium concentrations, δ34S sulfate and sulfate concentrations, tritium concentrations, and δ2Hwater and δ18O water are being used in this Phase I study. The aqueous chemical and isotopic analysis has identified areas on the terrace where groundwater is derived from mill

  16. 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.

  17. Geomorphic Effects, Chronologies, and Archaeological Significance of El Nino Floods in Southern Peru

    Science.gov (United States)

    Magilligan, F. J.; Manners, R.; Goldstein, P.

    2003-12-01

    The catastrophic effects of large floods have been well documented, on both contemporary and paleo-timecales, especially for the conterminous U.S. Less is known, however, about extreme events in hyper-arid sub-tropical climates where synoptic scale meteorological causes, such as El Nino-Southern Oscillation events, are the driving atmospheric mechanism. This research documents the geomorphic effects of extreme floods in the Moquegua River valley of southern Peru, in the core of the Atacama Desert. Using a combination of geomorphic mapping, hydrolologic modeling, aerial photography, ASTER satellite imagery, and GIS, we document the geomorphic signature of large contemporary floods within the mid-valley section (1500 masl) of the Rio Moquegua. Stratigraphic evidence and paleostage indicators of paleofloods, such as slackwater deposits and preserved high level flood gravels, are used to evidence late Holocene paleoflood magnitude-frequency relationships. On contemporary timescales, channel belt expansion by lateral erosion during large floods, such as the recent '97 and '98 floods, correspond to as much as 30-40 hectares of floodplain loss along the 20 km study reach. Sixty years of repeat aerial photography indicates that channel belt expansion and floodplain erosion commonly occurs along the Rio Moquegua. The frequent resetting of floodplain alluvium conditioned by these large floods is supported by radiocarbon dating of floodplain exposures. These dates indicate that most of the contemporary floodplain alluvium is younger that 560 14C yrs BP. The highest terrace remnants date to 3250 14C yrs BP and record a series of overbank flood gravels. Evidence for the regionally extensive Miraflores ENSO flood, ca. 1300 AD, exists in tributary and along mainstem sections. This flood has been documented along the coasts of Northern Chile to northern Peru, and has been evoked to explain significant social collapse. Our field evidence indicates that it catastrophically affected

  18. 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

  19. 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

  20. Engineering geologic conditions at the sinkhole entrance to Logan Cave, Benton County, Arkansas

    Science.gov (United States)

    Schulz, William H.; McKenna, Jonathan P.

    2004-01-01

    Logan Cave, located in Benton County, Arkansas, is inhabited by several endangered and threatened species. The cave and surrounding area was designated a National Wildlife Refuge under the control of the U.S. Fish and Wildlife Service (USFWS) in 1989. Cave researchers access the cave through a steep-sided sinkhole entrance, which also is one of the two access points used by endangered bats. There is evidence of instability of one of the entrance slopes that has raised concerns that the entrance could close if slope failure was to occur. At the request of USFWS, we performed an engineering geologic investigation of the sinkhole to evaluate stability of this slope, which is comprised of soil, and other mechanisms of sediment transport into the cave entrance. The investigation included engineering geologic mapping, sampling and laboratory testing of subsurface geologic materials, and slope-stability analysis. We found that the sinkhole slope that extends into the entrance of the cave is comprised of sandy and gravelly soil to the depths explored (6.4 meters). This soil likely was deposited as alluvium within a previous, larger sinkhole. Based on properties of the alluvium, geometry of the slope, and results of finite-element slope-stability analyses, we conclude that the slope is marginally stable. Future failures of the slope probably would be relatively thin and small, thus several would be required to completely close the cave entrance. However, sediment is accumulating within the cave entrance due to foot traffic of those accessing the cave, surface-water erosion and transport, and shallow slope failures from the other sinkhole slopes. We conclude that the entrance will be closed by sediment in the future, similar to another entrance that we identified that completely closed in the past. Several measures could be taken to reduce the potential for closure of the cave entrance, including periodic sediment removal, installation of materials that reduce erosion by

  1. 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

  2. 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

  3. 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

  4. Geologic map of the Hayward fault zone, Contra Costa, Alameda, and Santa Clara counties, California: a digital database

    Science.gov (United States)

    Graymer, R.W.; Jones, D.L.; Brabb, E.E.

    1995-01-01

    The Hayward is one of three major fault zones of the San Andreas system that have produced large historic earthquakes in the San Francisco Bay Area (the others being the San Andreas and Calaveras). Severe earthquakes were generated by this fault zone in 1836 and in 1868, and several large earthquakes have been recorded since 1868. The Hayward fault zone is considered to be the most probable source of a major earthquake in the San Francisco Bay Area, as much as 28% chance for a magnitude 7 earthquake before the year 2021 (Working Group on California Earthquake Probabilities, 1990). The Hayward fault zone, as described in this work, is a zone of highly deformed rocks, trending north 30 degrees west and ranging in width from about 2 to 10 kilometers. The historic earthquake generating activity has been concentrated in the western portion of the zone, but the zone as a whole reflects deformation derived from oblique right-lateral and compressive tectonic stress along a significant upper crustal discontinuity for the past 10 million or more years. The Hayward fault zone is bounded on the east by a series of faults that demarcate the beginning of one or more structural blocks containing rocks and structures unrelated to the Hayward fault zone. The eastern bounding faults are, from the south, the Calaveras, Stonybrook, Palomares, Miller Creek, and Moraga faults. These faults are not considered to be part of the Hayward fault zone, although they are shown on the map to demarcate its boundary. The western boundary of the zone is less clearly defined, because the alluvium of the San Francisco Bay and Santa Clara Valley basins obscures bedrock and structural relationships. Although several of the westernmost faults in the zone clearly project under or through the alluvium, the western boundary of the fault is generally considered to be the westernmost mapped fault, which corresponds more or less with the margin of thick unconsolidated surficial deposits. The Hayward fault

  5. Geologic map of the Jam Up Cave and Pine Crest quadrangles, Shannon, Texas, and Howell Counties, Missouri

    Science.gov (United States)

    Weary, David J.; Orndorff, Randall C.; Repetski, John E.

    2013-01-01

    The Jam Up Cave and Pine Crest 7.5-minute quadrangles are located in south-central Missouri within the Salem Plateau region of the Ozark Plateaus physiographic province. About 2,400 to 3,100 feet (ft) of flat-lying to gently dipping Lower Paleozoic sedimentary rocks, mostly dolomite, chert, sandstone, and orthoquartzite, overlie Mesoproterozoic igneous basement rocks. Unconsolidated residuum, colluvium, terrace deposits, and alluvium overlie the sedimentary rocks. Numerous karst features, such as sinkholes, caves, and springs, have formed in the carbonate rocks. Many streams are spring fed. The topography is a dissected karst plain with elevations ranging from about 690 ft where the Jacks Fork River exits the northeastern corner of the Jam Up Cave quadrangle to about 1,350 ft in upland areas along the north-central edge and southwestern corner of the Pine Crest quadrangle. The most prominent physiographic feature is the valley of the Jacks Fork River. This reach of the upper Jacks Fork, with its clean, swiftly-flowing water confined by low cliffs and bluffs, provides one of the most beautiful canoe float trips in the nation. Most of the land in the quadrangles is privately owned and used primarily for grazing cattle and horses and growing timber. A large minority of the land within the quadrangles is publicly owned by the Ozark National Scenic Riverways of the National Park Service. Geologic mapping for this investigation was conducted in 2005 and 2006.

  6. 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.

  7. Europe, a continent with high potential for the cultivation of the Burgundy truffle (Tuber aestivum/uncinatum

    Directory of Open Access Journals (Sweden)

    Gérard Chevalier

    2013-12-01

    Full Text Available The Burgundy truffle (Tuber aestivum/uncinatum grows, in Europe, in the most varied soils from a physical and chemical viewpoint. The only common point is the presence of a minimum level of exchangeable calcium in the soil. The truffle soils in Europe can be classified in two categories: the soils coming directly from the parent rock, and those formed from deposits covering the parent rock. The first group corresponds to most traditional truffle areas , France, Italy and Spain. It is also true for some soils from Ireland to Eastern Europe (Romania, Bulgaria, from Southern Europe (Greece, former Yugoslavia to Northern Europe (Sweden, Baltic countries. The sedimentary layers that cover most areas are from the secondary and tertiary era. The primary parent rocks are less frequent. The second group means quaternary or recent alluviums covering the parent rock on huge surfaces and at great depth sometimes. They characterize mainly countries Eastern and Northern Europe. By bringing within reason limestone, it is possible to cultivate T. aestivum/uncinatum on sedimentary soils non-calcareous or decalcified or even on soils issued from magmatic rocks (granite or metamorphic (schists. The possibilities of truffle cultivation in Europe are therefore enormous, the limiting factors not being the soil but the climate.

  8. 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.

  9. Completion Report for Well ER-8-1

    Energy Technology Data Exchange (ETDEWEB)

    Bechtel Nevada

    2004-11-01

    Well ER-8-1 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 well was drilled in October and November of 2002 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-8-1 is located at the north end of Yucca Flat approximately 580 meters south-southeast of the surface exposure of the Climax granitic intrusive. Detailed lithologic descriptions with stratigraphic assignments are included in this report. These are based on composite drill cuttings samples collected every 3 meters, and 21 sidewall samples taken at various depths between 351.1 and 573.0 meters, supplemented by incomplete geophysical log data. Detailed petrographic, geochemical, and mineralogical studies of rock samples were conducted on 22 samples of drill cuttings. Drilling began in tuffaceous alluvium, and the borehole penetrated Tertiary age bedded tuffs of the Volcanics of Oak Spring Butte and carbonate sediments of Paleozoic age, which were encountered at a depth of 334 meters. The borehole unexpectedly penetrated granite at the depth of 538.9 meters in which drilling was stopped. Contact metamorphic rocks and intrusive dikes associated with the Cretaceous-age granitic intrusive and at least one significant fault zone were encountered.

  10. 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.

  11. Landscapes of Santa Rosa Island, Channel Islands National Park, California

    Science.gov (United States)

    Schumann, R. Randall; Minor, Scott A.; Muhs, Daniel R.; Pigati, Jeffery S.

    2014-01-01

    Santa Rosa Island (SRI) is the second-largest of the California Channel Islands. It is one of 4 east–west aligned islands forming the northern Channel Islands chain, and one of the 5 islands in Channel Islands National Park. The landforms, and collections of landforms called landscapes, of Santa Rosa Island have been created by tectonic uplift and faulting, rising and falling sea level, landslides, erosion and deposition, floods, and droughts. Landscape features, and areas delineating groups of related features on Santa Rosa Island, are mapped, classified, and described in this paper. Notable landscapes on the island include beaches, coastal plains formed on marine terraces, sand dunes, and sand sheets. In this study, the inland physiography has been classified into 4 areas based on relief and degree of fluvial dissection. Most 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, or barrancas, leaving a relict floodplain above the present channel. A better understanding of the processes and mechanisms that created these landscapes enhances visitors’ enjoyment of their surroundings and contributes to improving land and resource management strategies in order to optimize and balance the multiple goals of conservation, preservation, restoration, and visitor experience.

  12. 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. 

  13. 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.

  14. 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.

  15. 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.

  16. A revised lithostratigraphic framework for the southern Yucca Mountain area, Nye County, Nevada

    Science.gov (United States)

    Spengler, R.W.; Byers, F.M.; Dickerson, R.P.

    2006-01-01

    An informal, revised lithostratigraphic framework for the southern Yucca Mountain area, Nevada has been developed to accommodate new information derived from subsurface investigations of the Nye County Early Warning Drilling Program. Lithologies penetrated by recently drilled boreholes at locations between Stagecoach Road and Highway 95 in southern Nye County include Quaternary and Pliocene alluvium and alluvial breccia, Miocene pyroclastic flow deposits, Miocene intercalated lacustrine siltstone and claystone sequences, early Miocene to Oligocene pre-volcanic sedimentary rocks, and Paleozoic strata. Of the 37 boreholes currently drilled, 21 boreholes have sufficient depth, spatial distribution, or traceable pyroclastic flow, pyroclastic fall, and reworked tuff deposits to aid in the lateral correlation of lithostrata. Medial and distal parts of regional pyroclastic flow deposits of Miocene age can be correlated with the Timber Mountain, Paintbrush, Crater Flat, and Tram Ridge Groups. Rocks intercalated between these regional pyroclastic flow deposits are substantially thicker than in the central part of Yucca Mountain, particularly near the downthrown side of major faults and along the southern extent of exposures at Yucca Mountain.

  17. Characterization of the Highway 95 Fault in lower Fortymile Wash using electrical and electromagnetic methods, Nye County, Nevada

    Science.gov (United States)

    Macy, Jamie P.; Kryder, Levi; Walker, Jamieson

    2012-01-01

    The Highway 95 Fault is a buried, roughly east-west trending growth fault at the southern extent of Yucca Mountain and Southwestern Nevada Volcanic Field. Little is known about the role of this fault in the movement of groundwater from the Yucca Mountain area to downgradient groundwater users in Amargosa Valley. The U.S. Geological Survey (USGS) Arizona Water Science Center (AZWSC), in cooperation with the Nye County Nuclear Waste Repository Project Office (NWRPO), has used direct current (DC) resistivity, controlled-source audio magnetotelluric (CSAMT), and transient electromagnetics (TEM) to better understand the fault. These geophysical surveys were designed to look at structures buried beneath the alluvium, following a transect of wells for lithologic control. Results indicate that the fault is just north of U.S. Highway 95, between wells NC-EWDP-2DB and -19D, and south of Highway 95, east of well NC-EWDP-2DB. The Highway 95 Fault may inhibit shallow groundwater movement by uplifting deep Paleozoic carbonates, effectively reducing the overlying alluvial aquifer thickness and restricting the movement of water. Upward vertical hydraulic gradients in wells proximal to the fault indicate that upward movement is occurring from deeper, higher-pressure aquifers.

  18. Geohydrology of Monitoring Wells Drilled in Oasis Valley near Beatty, Nye County, Nevada, 1997

    Science.gov (United States)

    Robledo, Armando R.; Ryder, Philip L.; Fenelon, Joseph M.; Paillet, Frederick L.

    1999-01-01

    Twelve monitoring wells were installed in 1997 at seven sites in and near Oasis Valley, Nevada. The wells, ranging in depth from 65 to 642 feet, were installed to measure water levels and to collect water-quality samples. Well-construction data and geologic and geophysical logs are presented in this report. Seven geologic units were identified and described from samples collected during the drilling: (1) Ammonia Tanks Tuff; (2) Tuff of Cutoff Road; (3) tuffs, not formally named but informally referred to in this report as the 'tuff of Oasis Valley'; (4) lavas informally named the 'rhyolitic lavas of Colson Pond'; (5) Tertiary colluvial and alluvial gravelly deposits; (6) Tertiary and Quaternary colluvium; and (7) Quaternary alluvium. Water levels in the wells were measured in October 1997 and February 1998 and ranged from about 18 to 350 feet below land surface. Transmissive zones in one of the boreholes penetrating volcanic rock were identified using flowmeter data. Zones with the highest transmissivity are at depths of about 205 feet in the 'rhyolitic lavas of Colson Pond' and 340 feet within the 'tuff of Oasis Valley.'

  19. Accumulation and erosion of aeolian sediments in the northeastern Qinghai-Tibetan Plateau and implications for provenance to the Chinese Loess Plateau

    Science.gov (United States)

    Liu, Xiang-Jun; Xiao, Guoqiao; E, Chongyi; Li, Xiangzhong; Lai, Zhongping; Yu, Lupeng; Wang, Zhong

    2017-03-01

    The northern and northeastern Qinghai-Tibetan Plateau (QTP) is regarded as one important source region of the Chinese Loess Plateau (CLP). However, how the fine grain sediments in this region were transported to the CLP remains debatable. In this study, we dated aeolian sediments, alluviums, beach sediments, and sand wedges in the northeastern QTP using optical dating, combined with previously reported ages, explored the aeolian sediment deposition patterns in this region. The dating results shown that aeolian sediments mainly accumulated during the marine isotope stage (MIS) 3 and since the last deglaciation, alluvial sediments mainly deposited during the middle to late MIS 3 (between ∼40 ka and 22 ka), and sand wedges formed during the MIS 4 and MIS 2 cold intervals. Based on the sedimentary stratigraphic characteristics and existing optical dating chronologies, we propose that fine grain sediments in the northern and northeastern QTP were eroded and carried to the CLP by westerly wind during last glacial and stadial cold stages. However, during last interglacial and interstadial warm stages, aeolian sediments deflated from western barren lands and deserts were mainly trapped in the northeastern QTP, and some were transported to the Alax arid zone or Yinchuan-Hetao plain by rivers that flow out of QTP, then transported to the CLP by northwesterly Asian winter monsoon (AWM). This cold stage westerly wind transport, warm stage rivers plus AWM transport pattern has existed at least since the late middle Pleistocene.

  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. Groundwater exploration using 2D Resistivity Imaging in Pagoh, Johor, Malaysia

    Science.gov (United States)

    Kadri, Muhammad; Nawawi, M. N. M.

    2010-12-01

    Groundwater is a very important component of water resources in nature. Since the demand of groundwater increases with population growth, it is necessary to explore groundwater more intensively. In Malaysia only less than 2% of the present water used is developed from groundwater. In order to determine the existence of usable groundwater for irrigation and drinking purposes in Pagoh, 2D resistivity imaging technique was utilized. The 2-D resistivity imaging technique utilized the Wenner—Schlumberger electrode array configuration because this array is moderately sensitive to both horizontal and vertical structures. Three lines were surveyed for groundwater delineation purpose The length for each survey lines are 400 meters. At Pagoh, the survey site shows the existence of groundwater. It is indicated by the resistivity values about 10-100 ohm-m. The maximum depth of investigation survey is 77 meters. In general the results show that the subsurface is made up of alluvium and clay and the high resistivity values of more than 1000 ohm-m near the surface is due laterite and the end of the depth can be interpreted as mixture of weathered material or bedrock.

  2. 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.

  3. Summary of Quaternary geology of the Municipality of Anchorage, Alaska

    Science.gov (United States)

    Schmoll, H.R.; Yehle, L.A.; Updike, R.G.

    1999-01-01

    Quaternary geology of the Upper Cook Inlet region is dominated by deposits of glacier retreats that followed repeated advances from both adjacent and more distant mountains. At several levels high on the mountains, there are remnant glacial deposits and other features of middle or older Pleistocene age. Late Pleistocene lateral moraines along the Chugach Mountain front represent successively younger positions of ice retreat from the last glacial maximum. As the trunk glacier retreated northeastward up the Anchorage lowland, Cook Inlet transgressed the area, depositing the Bootlegger Cove Formation and Tudor Road deposits. The glacier then readvanced to form the latest Pleistocene Elmendorf Moraine, a prominent feature that trends across the Anchorage lowland. Extensive alluvium was deposited both concurrently and somewhat later as Cook Inlet regressed. Mountain valleys contain (1) locally preserved moraines possibly of early Holocene age; (2) poorly preserved moraine remnants of older late Holocene age; and (3) well-preserved moraines formed mainly during the Little Ice Age. Glaciers still occupy large parts of the mountains, the upper ends of some mountain valleys, and small cirques. Holocene landslide deposits, including those formed during the great Alaska earthquake of 1964, occur throughout the area, especially along bluffs containing the Bootlegger Cove Formation.

  4. 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.

  5. 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.

  6. Integrated approach for demarcating subsurface pollution and saline water intrusion zones in SIPCOT area: a case study from Cuddalore in Southern India.

    Science.gov (United States)

    Sankaran, S; Sonkamble, S; Krishnakumar, K; Mondal, N C

    2012-08-01

    This paper deals with a systematic hydrogeological, geophysical, and hydrochemical investigations carried out in SIPCOT area in Southern India to demarcate groundwater pollution and saline intrusion through Uppanar River, which flows parallel to sea coast with high salinity (average TDS 28, 870 mg/l) due to back waters as well as discharge of industrial and domestic effluents. Hydrogeological and geophysical investigations comprising topographic survey, self-potential, multi-electrode resistivity imaging, and water quality monitoring were found the extent of saline water intrusion in the south and pockets of subsurface pollution in the north of the study area. Since the area is beset with highly permeable unconfined quaternary alluvium forming potential aquifer at shallow depth, long-term excessive pumping and influence of the River have led to lowering of the water table and degradation of water quality through increased salinity there by generating reversal of hydraulic gradient in the south. The improper management of industrial wastes and left over chemicals by closed industries has led surface and subsurface pollution in the north of the study area.

  7. Nitrate probability mapping in the northern aquifer alluvial system of the river Tagus (Portugal) using Disjunctive Kriging.

    Science.gov (United States)

    Mendes, Maria Paula; Ribeiro, Luís

    2010-02-01

    The Water Framework Directive and its daughter directives recognize the urgent need to adopt specific measures against the contamination of water by individual pollutants or a group of pollutants that present a significant risk to the quality of water. Probability maps showing that the nitrate concentrations exceed a legal threshold value in any location of the aquifer are used to assess risk of groundwater quality degradation from intensive agricultural activity in aquifers. In this paper we use Disjunctive Kriging to map the probability that the Nitrates Directive limit (91/676/EEC) is exceeded for the Nitrate Vulnerable Zone of the River Tagus alluvium aquifer. The Tagus alluvial aquifer system belongs to one of the most productive hydrogeological unit of continental Portugal and it is used to irrigate crops. Several groundwater monitoring campaigns were carried out from 2004 to 2006 according to the summer crops cycle. The study reveals more areas on the west bank with higher probabilities of contamination by nitrates (nitrate concentration values above 50mg/L) than on the east bank. The analysis of synthetic temporal probability map shows the areas where there is an increase of nitrates concentration during the summers.

  8. 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.

  9. Coupled Transport of PAH and Surfactants in Natural Aquifer Material

    Science.gov (United States)

    Danzer, J.; Grathwohl, P.

    1998-03-01

    Surfactants in aqueous solution adsorb onto mineral surfaces and form micelles above the critical micelle concentration (CMC) due to their physico-chemical properties. Hydrophobic organic compounds such as polycyclic aromatic hydrocarbons (PAHs) have a high affinity for the adsorbed surfactant layers (monomers, hemimicelles and admicelles) and to the micelles in the mobile aqueous phase. The transport of PAHs is controlled by the concentration of the surfactant and the partition coefficients, of the PAHs between water and admicelles (adsolubilization: K adm) and water and micelles (solubilization: K mic), respectively. These partition coefficients were measured in laboratory batch and column experiments using phenanthrene as a chemical probe for the PAHs, a non-ionic surfactant (Terrasurf G50), natural aquifer sand (River Neckar Alluvium: RNA) and its petrographic subcomponents. The sorption of the surfactant can be described by a linear isotherm for concentrations below the CMC and a sorption maximum above the CMC, which both depend on the grain size and the surfactant accessible internal surface area of the particles. K adm was found to be higher than K mic. Both depend on the surfactant's properties, such as alkyl chain length, polar headgroup or ethoxylation. In column experiments an increasing retardation of phenanthrene was observed up to the CMC followed by a facilitated transport at surfactant concentration several times the CMC.

  10. 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.

  11. 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.

  12. 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.

  13. Potential effects of surface coal mining on the hydrology of the Horse Creek area, Sheridan and Moorehead coal fields, southeastern Montana

    Science.gov (United States)

    McClymonds, N.E.

    1985-01-01

    The Horse Creek area of the Sheridan and Moorhead coal fields, 16 miles east of the Decker Coal Mines near the Tongue River, contains large reserves of Federally owned coal that have been identified for potential lease sale. A hydrologic study was conducted in the area to describe existing hydrologic systems and to assess potential impacts of surface coal mining on local water resources. Hydrologic data collected from private wells, observation wells, test holes, and springs indicate that the aquifers are primarily coal and sandstone beds in the upper part of the Tongue River Member of the Fort Union Formation (Paleocene age) and sand and gravel of valley alluvium (Pleistocene and Holocene age). Surface-water resources are mostly limited to a few stock ponds receiving discharge from springs in the higher ports of the area. Two stock wells, one spring, and three stock ponds receiving discharge from springs supply most of the water used within the Horse Creek basin; the only use is watering of livestock. Mining of the Anderson and Dietz coal beds would destroy one stock well and two ponds receiving discharge from springs, and would lower the potentiometric surface within the coal and sandstone aquifers. Although mining would alter existing hydrologic systems, alternative deeper water supplies are available. (USGS)

  14. Geomorphic response of an active metamorphic core-complex in a collisional orogen: Example from the Lunggar Shan, Southern Tibet

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, M H; Stockli, D F [Department of Geology, University of Kansas, 1475 Jayhawk Blvd., Lawrence, KS 66044 (United States); Kapp, P A [Department of Geosciences, University of Arizona, Tucson, AZ (United States)], E-mail: mht@ku.edu

    2008-07-01

    We present structural and neotectonic mapping from the Lunggar Shan rift in southern Tibet. The Lunggar Shan is a N-trending mountain range {approx}70 km long N-S and up to 40 km wide E-W. The Lunggar Shan is bounded on its east side by a low-angle (<40{sup 0}) east-dipping detachment fault that juxtaposes mylonitic gneiss and variably deformed granites in its footwall against alluvial fans and Neogene gravels in its hangingwall. Foliations in the mylonitic footwall dip < 40 deg. east and stretching lineations are east plunging. The range front detachment is presently inactive as indicated by undisturbed moraines and Quaternary sediments that overlie it. However, we consider the Lunggar Shan detachment to be an active structure, as inferred by range parallel fault scarps cutting Quaternary alluvium located 4-5 km into the hangingwall basin, with >40 m of throw on individual scarps. An intriguing observation is that an intrabasinal topographic high is actively developing near areas of inferred maximum extension, with lacustrine sediments being uplifted and eroded. This observation indicates that the rift basin initially developed as a typical half-graben system that underwent a transition from deposition, to uplift and erosion perhaps as a result of isostatic rebound of the footwall at depth, warping the overlying hangingwall basin. If correct, the Lunggar Shan may represent a modern analogue to the supradetachment basin model.

  15. Investigation of land-use spectral signatures. Ph.D. Thesis. Final Report

    Science.gov (United States)

    Hagewood, J. F.

    1975-01-01

    A technique was developed to obtain bidirectional reflectance data from natural surfaces by using a folding mirror to transfer the reflected energy from the test surface to a spectroradiometer. The folding mirror was a first surface reflector made by stretching Mylar vacuum coated with aluminum over a light weight frame. The optically folding mirror was positioned over the test surfaces with a moveable platform for both laboratory and field tests. Field tests were conducted using a tethered balloon system to position the folding mirror. A spectroradiometer was designed and built specifically for this investigation. The spectroradiometer had an angular field of view of twenty-four minutes in one axis and ten minutes in the other axis. The radiometer was capable of detecting energies in small bandwidths throughout the electromagnetic spectrum from 0.3 microns to 3.0 microns. Bidirectional reflectance data and variations in the data with source angles were obtained for Saint Augustine grass, Bermuda grass, and a black alluvium soil from the Mississippi River delta.

  16. 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.)

  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. Pumice in the interglacial Whidbey Formation at Blowers Bluff, central Whidbey Island, WA, USA

    Science.gov (United States)

    Dethier, D.P.; Dragovich, J.D.; Sarna-Wojcicki, A. M.; Fleck, R.J.

    2008-01-01

    A new 40Ar/39Ar age of 128??9 ka and chemical analyses of pumice layers from interglacial alluvium at Blowers Bluff, Whidbey Island, WA, show that the deposits are part of the Whidbey Formation, a widespread, mainly subsurface unit. Glass chemistry of the dated dacitic pumice does not match any analyzed northern Cascade source, but upper Pleistocene dacites from Glacier Peak and early Pleistocene silicic rocks from the Kulshan caldera are chemically similar. The chemistry of pumiceous dacite in younger units, including the latest Pleistocene Partridge Gravel, is similar to that of the dated material. The deep troughs of the modern northern Puget lowland must have been filled during deposition of the Whidbey Formation, allowing volcanic-rich sediment to reach what is now Whidbey Island. Topographic analysis of LIDAR images demonstrates that extensive erosion occurred during latest Pleistocene ice retreat. The Partridge Gravel likely records subglacial fluvial erosion along an ice tunnel and ice-marginal deposition into adjacent marine waters. Pumice in the Partridge Gravel probably was reworked from stratigraphically and topographically lower deposits, including those at Blowers Bluff. ?? 2007 Elsevier Ltd and INQUA.

  19. Potential effects of surface coal mining on the hydrology of the Corral Creek area, Hanging Woman Creek coal field, southeastern Montana

    Science.gov (United States)

    McClymonds, N.E.

    1984-01-01

    The Corral Creek area of the Hanging Woman Creek coal field, 9 miles east of the Decker coal mines near the Tongue River, contains large reserves of Federal coal that have been identified for potential lease sale. A hydrologic study was conducted in the area to describe existing hydrologic systems and to study assess potential impacts of surface coal mining on local water resources. Hydrogeologic data collected indicate that aquifers are coal and sandstone beds within the Tongue River Member of the Fort Union Formation (Paleocene age) and sand and gravel in valley alluvium (Pleistocene and Holocene age). Surface-water resources are limited to a few spring-fed stock ponds in the higher parts of the area and the intermittent flow of Corral Creek near the mouth. Most of the stock ponds in the area become dry by midsummer. Mining of the Anderson coal bed would remove three stock wells and would lower the potentiometric surface within the coal and sandstone aquifers. The alluvial aquifer beneath Corral Creek and South Fork would be removed. Although mining would alter the existing hydrologic systems and remove several shallow wells, alternative ground-water supplies are available that could be developed to replace those lost by mining. (USGS)

  20. Biochronology and biostratigraphy of the Uquía Formation (Pliocene early Pleistocene, NW Argentina) and its significance in the Great American Biotic Interchange

    Science.gov (United States)

    Reguero, M. A.; Candela, A. M.; Alonso, R. N.

    2007-01-01

    The Uquía Formation crops out in the Quebrada de Humahuaca in Jujuy province, Eastern Cordillera, NW Argentina. This unit is composed of a sequence of fluviatile sediments and water-laid air-fall tuff beds; it is approximately 260 m thick and unconformably overlain by Pleistocene conglomerates and Quaternary alluvium. The sediments have been folded into a syncline and broken by several faults that generally trend northwest-southeast. Following Castellanos stratigraphy, we characterize three units (Lower, Middle, and Upper) of the Uquía Formation. Biochronologically, the Lower Unit is assigned to the late Chapadmalalan, the Middle Unit ("Uquian fauna") to the late Vorohuean and Sanandresian, and the Upper Unit to the Ensenadan. Biostratigraphic evidence provides a calibration of important biochronologic events in the Great American Biotic Interchange (GABI), namely, the first appearances of Erethizon, Hippidion, and proboscideans at 2.5 Ma (late Pliocene) in South America. Geological and paleobiological evidence suggest that during the late Pliocene, the area could have been a wide intermountain valley at 1400-1700 m elevation, with a more humid environment than that of the present day and some wet-dry seasonality that permitted the coexistence of forest and open areas. Uquian mammals also indicate that northwestern Argentina and the Pampean region have represented distinct biogeographical areas since at least the late Pliocene.

  1. Geologic map of the White Hall quadrangle, Frederick County, Virginia, and Berkeley County, West Virginia

    Science.gov (United States)

    Doctor, Daniel H.; Orndorff, Randall C.; Parker, Ronald A.; Weary, David J.; Repetski, John E.

    2010-01-01

    The White Hall 7.5-minute quadrangle is located within the Valley and Ridge province of northern Virginia and the eastern panhandle of West Virginia. The quadrangle is one of several being mapped to investigate the geologic framework and groundwater resources of Frederick County, Va., as well as other areas in the northern Shenandoah Valley of Virginia and West Virginia. All exposed bedrock outcrops are clastic and carbonate strata of Paleozoic age ranging from Middle Cambrian to Late Devonian. Surficial materials include unconsolidated alluvium, colluvium, and terrace deposits of Quaternary age, and local paleo-terrace deposits possibly of Tertiary age. The quadrangle lies across the northeast plunge of the Great North Mountain anticlinorium and includes several other regional folds. The North Mountain fault zone cuts through the eastern part of the quadrangle; it is a series of thrust faults generally oriented northeast-southwest that separate the Silurian and Devonian clastic rocks from the Cambrian and Ordovician carbonate rocks and shales. Karst development in the quadrangle occurs in all of the carbonate rocks. Springs occur mainly near or on faults. Sinkholes occur within all of the carbonate rock units, especially where the rocks have undergone locally intensified deformation through folding, faulting, or some combination.

  2. 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.

  3. Hydrothermal alteration at the Roosevelt Hot Springs thermal area, Utah: Petrographic characterization of the alteration to 2 kilometers depth

    Energy Technology Data Exchange (ETDEWEB)

    Ballantyne, J.M.; Parry, W.T.

    1978-04-01

    Hydrothermal alteration in drill cuttings from Thermal Power drillhole 14-2, Roosevelt Hot Springs Thermal area, has been studied petrographically. The hole is sited in alluvium approximately 1.6 km southeast of the old Resort and was rotary drilled to a depth of 1866.0 m. The exact hole location is 2310 FNL, 350 FWL, Sec. 2, Twp 27S, Rge 9W, elevation 1908.5 m. Core was extracted from 792.5 to 795.5 m. Thin sections were made from samples at 15.2 m intervals of drill cuttings collected at 1.5 or 3.0 m intervals during drilling. Thin sections were made of 1.5 or 3.0 m intervals from 274.3 to 304.8 m, 487.9 to 581.2 m, and 868.7 to 899.2 m. These intervals were chosen for close spaced sampling on the basis of increases in temperature, porosity, conductivity and acoustic velocity shown in geophysical logs. A total of 153 thin sections of cuttings were made, and an additional 9 sections were made from the core. Depths of thin section samples are listed in the appendix. A visual estimate of the percentage of each rock type was made for each thin section.

  4. 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.

  5. Ground-water resources and geology of St. Croix County, Wisconsin

    Science.gov (United States)

    Borman, R.G.

    1976-01-01

    The increasing need for good-quality ground water in St. Croix County, caused by a steadily increasing population, can be met from the sand-and-gravel and sandstone aquifers. As much as 15 gallons per minute (0.95 litres per second) can be obtained from wells almost everywhere in the county. Yields of more than 1,000 gallons per minute (63 litres per second) are available from glacial deposits and alluvium where there is sufficient thickness of saturated sand and gravel. The sandstone aquifer underlies the entire county and is more than 1,000 feet (300 metres) thick in the southwest near River Falls. In St. Croix County the sandstone aquifer is all bedrock younger than Precambrian age and includes, in ascending order, from oldest to youngest, sandstones of Cambrian age (in ascending order, the Mount Simon, Eau Claire, Galesville, and Franconia Sandstones, and the Trempealeau Formation); and the Prairie du Chien Group, St. Peter Sandstone, and Galena-Platteville unit (Platteville and Decorah Formations and Galena Dolomite, undifferentiated), all of Ordovician age. This aquifer is capable of yielding more than 1,000 gallons per minute (63 litres per second) to wells in much of the county and is the principal source of municipal water.

  6. Ground-water quality in Bannock, Bear Lake, Caribou, and part of Power counties, southeastern Idaho

    Science.gov (United States)

    Seitz, H.R.; Norvitch, R.F.

    1979-01-01

    The 103 wells sampled during the study establish a quasi-network that could be resampled in the future to document and analyze changes in ground-water quality in the southeastern Idaho study area. The main aquifers are categorized as alluvium of Quaternary age, basalt of Quaternary and (or) Tertiary age, rocks of the Salt Lake Formation of Tertiary age, and undifferentiated bedrock of pre-Tertiary age. Dissolved solids, hardness, nitrite plus nitrate as nitrogen, and chloride concentrations in the ground waters ranged from 165 to 1,690; 78 to 1,700; 0 to 29; and 1.9 to 360 milligrams per liter, respectively. The areal distributions of these constituents are shown on maps. The range and median values of these same constituents are tabulated by aquifer occurrence. Some of the most mineralized and hardest waters occur in the basalt aquifer near travertine deposits (or terraces), which are composed of calcium carbonate precipitates from mineral springs. For irrigation purposes, all the waters are classified as having low-sodium hazard. Most have medium- to high-salinity hazard. (Woodard-USGS)

  7. 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.

  8. Palynology of oxygen isotope stage 6 and substage 5e from the cover beds of a marine terrace, Taranaki, New Zealand

    Science.gov (United States)

    Bussell, M. Royd

    1990-07-01

    Cover beds on uplifted Quaternary marine terraces in the Taranaki-Wanganui area of New Zealand include organic deposits which yield abundant pollen. In the west at Ohawe, marine shore platform deposits are overlain by laterally extensive lignites and laharic breccia, interbedded with alluvium and capped by tephra-rich loess. Following a time of presumably interglacial marine deposition on the platform, a long period of glacial climate is suggested by pollen floras dominated by grass and shrubland taxa. Trees were sparse, but the abundance of podocarps, Nothofagus, and tree ferns increased during at least one interval, suggesting minor climatic amelioration. Near the top of the section, a major change in regional vegetation is recorded by a dominance of pollen derived from podocarp-hardwood forest taxa, including Ascarina, interpreted as indicating a fully interglacial climate. The marine platform, previously assigned to oxygen isotope substage 5e, is now placed in stage 7. The overlying deposits were deposited during glacial stage 6, while interglacial substage 5e is recorded by sediment and pollen assemblages near the top of the section.

  9. 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.

  10. 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.

  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. 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.

  13. Assessment of liquefaction potential during earthquakes by arias intensity

    Science.gov (United States)

    Kayen, R.E.; Mitchell, J.K.

    1997-01-01

    An Arias intensity approach to assess the liquefaction potential of soil deposits during earthquakes is proposed, using an energy-based measure of the severity of earthquake-shaking recorded on seismograms of the two horizontal components of ground motion. Values representing the severity of strong motion at depth in the soil column are associated with the liquefaction resistance of that layer, as measured by in situ penetration testing (SPT, CPT). This association results in a magnitude-independent boundary that envelopes initial liquefaction of soil in Arias intensity-normalized penetration resistance space. The Arias intensity approach is simple to apply and has proven to be highly reliable in assessing liquefaction potential. The advantages of using Arias intensity as a measure of earthquake-shaking severity in liquefaction assessment are: Arias intensity is derived from integration of the entire seismogram wave form, incorporating both the amplitude and duration elements of ground motion; all frequencies of recorded motion are considered; and Arias intensity is an appropriate measure to use when evaluating field penetration test methodologies that are inherently energy-based. Predictor equations describing the attenuation of Arias intensity as a function of earthquake magnitude and source distance are presented for rock, deep-stiff alluvium, and soft soil sites.

  14. Groundwater surface water interactions and the role of phreatophytes in identifying recharge zones

    Directory of Open Access Journals (Sweden)

    T. S. Ahring

    2012-11-01

    Full Text Available Groundwater and surface water interactions within riparian corridors impact the distribution of phreatophytes that tap into groundwater stores. The changes in canopy area of phreatophytes over time is related to changes in depth to groundwater, distance from a stream or river, and hydrologic soil group. Remote sensing was used to determine the location of trees with pre-development and post-development aerial photography over the Ogallala Aquifer in the central plains of the United States. It was found that once the depth to groundwater becomes greater than about 3 m, tree populations decrease as depth to water increases. This subsequently limited the extent of phreatophytes to within 700 m of the river. It was also found that phreatophytes have a higher likelihood of growing on hydrologic soil groups with higher saturated hydraulic conductivity. Phreatophytes exist along portions of the Arkansas River corridor where significant decreases in groundwater occurred as long as alluvium exists to create perched conditions where trees survive dry periods. Significant decreases (more that 50% in canopy cover exists along river segments where groundwater declined by more than 10 m, indicating areas with good hydraulic connectivity between surface water and groundwater. Thus, interpretation of changes in phreatophyte distribution using historical and recent aerial photography is important in delineating zones of enhanced recharge where aquifers might be effectively recharged through diversion of surface water runoff.

  15. Groundwater surface water interactions through streambeds and the role of phreatophytes in identifying important recharge zones

    Directory of Open Access Journals (Sweden)

    T. S. Ahring

    2012-06-01

    Full Text Available Groundwater and surface water interactions within riparian corridors impact the distribution of phreatophytes that tap into groundwater stores. The changes in canopy area of phreatophytes over time is related to changes in depth to groundwater, distance from a stream or river, and hydrologic soil group. Remote sensing was used to determine the location of trees with predevelopment and post-development aerial photography over the Ogallala Aquifer in the central plains of the United States. It was found that once the depth to groundwater becomes greater than about 3 m, tree populations decrease as depth to water increases. This subsequently limited the extent of phreatophytes to within 700 m of the river. It was also found that phreatophytes have a higher likelihood of growing on hydrologic soil groups with higher saturated hydraulic conductivity. Phreatophytes exist along portions of the Arkansas River corridor where significant decreases in groundwater occurred as long as alluvium exists to create perched conditions where trees survive dry periods. Significant decreases (more that 50% in canopy cover exists along river segments where groundwater declined by more than 10 m, indicating areas with good hydraulic connectivity between surface water and groundwater. Thus, interpretation of changes in phreatophyte distribution using historical and recent aerial photophaphy is important in delineating zones of enhanced recharge where aquifers might be effectively recharged through diversion of surface water runoff.

  16. CARNELIAN containment data report

    Energy Technology Data Exchange (ETDEWEB)

    Stubbs, T [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    1998-07-01

    The CARNELIAN event was detonated in hole U4af of the Nevada Test Site as indicated in figure 1 .l. The CARNELIAN device had a depth-of-burial (DOB) of 208 m in the alluvium of Area 4 , about 70 m above the Paleozoic formation and 330 m above the standing water level, as shown in the geologic cross-sections of figure 1.2(l) Figure 1 3 displays the local surface area showing nearby events Stemming of the 2 44 m diameter emplacement hole followed the plan shown in figure 1 4. A log of the stemming operations was maintained by Holmes & Narver(2) Detonation time was about 07 00 PDT on July 28,1977, and collapse progressed to the surface at about 19 minutes after the detonation resulting in a crater having a "cookie-cutter" geometry (steep walls with a relatively flat bottom) with a mean radius of 32 2 m and a maximum depth of 10 5 m No radiation arrivals were detected above ground and the CARNELIAN containment was considered successful

  17. Investigation of a large collapse sinkhole affecting a multi-storey building by means of geophysics and the trenching technique (Zaragoza city, NE Spain)

    Science.gov (United States)

    Gutiérrez, F.; Galve, J. P.; Lucha, P.; Bonachea, J.; Jordá, L.; Jordá, R.

    2009-09-01

    An active sinkhole around 100 m long has been investigated in the city of Zaragoza (NE Spain). Subsidence activity on this depression, including the sudden occurrence of a collapse sinkhole 5 m across, led to the abandonment of a factory in the 1990s. At the present time, a building with 100 flats and shallow pad foundations partially built on the sinkhole, is affected by rapid differential settlement. The development of the sinkhole results from the karstification of the halite- and glauberite- bearing bedrock and the sagging and collapse of the overlying bedrock and alluvium, more than 30 m thick. GPR and electrical resistivity profiles have provided information on the distribution and geometry of the subsidence structure. The application of the trenching technique and geochronological methods (AMS and OSL dating) has allowed us to infer objective and practical data on the sinkhole including (1) Limits of the subsidence structure, (2) subsidence mechanisms, (3) cumulative subsidence (>408 cm), (4) subsidence rates on specific failure planes (>1.8 cm/year), (5) episodic displacement regime of some fault planes. The available information indicates that the progressive deformation recorded in the building will continue and might be punctuated by events of more rapid displacement. This work illustrates the practicality of the trenching technique for the study of sinkholes in mantled karst areas.

  18. 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.

  19. 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.

  20. 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.

  1. Geology and geophysics of the southern Raft River Valley geothermal area, Idaho, USA

    Science.gov (United States)

    Williams, Paul L.; Mabey, Don R.; Zohdy, Adel A.R.; Hans, Ackerman; Hoover, Donald B.; Pierce, Kenneth L.; Oriel, Steven S.

    1976-01-01

    The Raft River valley, near the boundary of the Snake River plain with the Basin and Range province, is a north-trending late Cenozoic downwarp bounded by faults on the west, south, and east. Pleistocene alluvium and Miocene-Pliocene tuffaceous sediments, conglomerate, and felsic volcanic rocks aggregate 2 km in thickness. Large gravity, magnetic, and total field resistivity highs probably indicate a buried igneous mass that is too old to serve as a heat source. Differing seismic velocities relate to known or inferred structures and to a suspected shallow zone of warm water. Resistivity anomalies reflect differences of both composition and degree of alteration of Cenozoic rocks. Resistivity soundings show a 2 to 5 ohm·m unit with a thickness of 1 km beneath a large part of the valley, and the unit may indicate partly hot water and partly clayey sediments. Observed self-potential anomalies are believed to indicate zones where warm water rises toward the surface. Boiling wells at Bridge, Idaho are near the intersection of north-northeast normal faults which have moved as recently as the late (?) Pleistocene, and an east-northeast structure, probably a right-lateral fault. Deep circulation of ground water in this region of relatively high heat flow and upwelling along faults is the probable cause of the thermal anomaly.

  2. 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.

  3. 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.

  4. 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.

  5. Review of the general geology and solid-phase geochemical studies in the vicinity of the Central Oklahoma aquifer

    Science.gov (United States)

    Mosier, Elwin L.; Bullock, John H.

    1988-01-01

    The Central Oklahoma aquifer is the principal source of ground water for municipal, industrial, and rural use in central Oklahoma. Ground water in the aquifer is contained in consolidated sedimentary rocks consisting of the Admire, Council Grove, and Chase Groups, Wellington Formation, and Garber Sandstone and in the unconsolidated Quaternary alluvium and terrace deposits that occur along the major stream systems in the study area. The Garber Sandstone and the Wellington Formation comprise the main flow system and, as such, the aquifer is often referred to as the 'Garber-Wellington aquifer.' The consolidated sedimentary rocks consist of interbedded lenticular sandstone, shale, and siltstone beds deposited in similar deltaic environments in early Permian time. Arsenic, chromium, and selenium are found in the ground water of the Central Oklahoma aquifer in concentrations that, in places, exceed the primary drinking-water standards of the Environmental Protection Agency. Gross-alpha concentrations also exceed the primary standards in some wells, and uranium concentrations are uncommonly high in places. As a prerequisite to a surface and subsurface solid-phase geochemical study, this report summarizes the general geology of the Central Oklahoma study area. Summaries of results from certain previously reported solid-phase geochemical studies that relate to the vicinity of the Central Oklahoma aquifer are also given; including a summary of the analytical results and distribution plots for arsenic, selenium, chromium, thorium, uranium, copper, and barium from the U.S. Department of Energy's National Uranium Resource Evaluation (NURE) Program.

  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. 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.

  8. 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.

  9. Numerical Simulation of Cavity Pressure and Temperature in Underground Detonation%地下爆炸空腔压力和温度历程数值模拟

    Institute of Scientific and Technical Information of China (English)

    王铁良; 曹渊; 张建鑫

    2011-01-01

    A mathematical model is built for cavity temperature and pressure in underground detonation after the completion of cavity growth. It incorporates gas permeation in porous media, heat radiation between gas and cavity-wall and heat conduction between gas and ambient media. A corresponding one-dimensional code on the basis of spherical symmetry finite volume method is developed. Cavity pressure and temperature of an underground nuclear test in alluvium at Nevada Test Site are computed. Measurment data of cavity pressure are analyzed in detail.%将气体的渗透、气体与空腔壁的辐射换热、气体与周围介质的热传导三种因素相结合,建立地下爆炸空腔稳定后气体温度和压力变化的数学模型,编制一维球对称有限体积数值模拟程序.用该程序对美国内华达试验场冲积土介质中一次地下核爆炸空腔温度和压力历程进行数值模拟,并对压力监测结果进行分析.

  10. Application of time-domain electromagnetic method in mapping saltwater intrusion of a coastal alluvial aquifer, North Oman

    Science.gov (United States)

    El-Kaliouby, Hesham; Abdalla, Osman

    2015-04-01

    One-third of the population of Oman depends on the groundwater extracted from the alluvium deposits located along the coast of the Gulf of Oman. However, groundwater depletion and seawater intrusion constitute major challenges along the coastal water accumulations in Oman. The objective of this study is to locate the extent of seawater intrusion and to map the shallow alluvial aquifer in the region, where water accumulates from the rain or the flooding at AlKhod dam. In order to assess the effect of groundwater infiltration, which recharges the aquifer and fights the seawater invasion, a quantitative approach for the groundwater quality and distribution is required to provide reasonable knowledge on the spatial distribution of the aquifers, their thickness and the type of sediments. When groundwater wells and their subsurface geologic and electrical logs are not available or not deep enough, surface geophysical surveys can be considered due to their low cost and short acquisition time. The application of time-domain electromagnetic (TDEM) method in Al-Khod area, Oman has proven to be a successful tool in mapping the fresh/saline water interface and for locating the depth of fresh water aquifer. The depths and inland extents of the saline zone were mapped along three N-S TDEM profiles. The depths to the freshwater table and saline interface calculated from TDEM closely match the available well data.

  11. 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.

  12. 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.

  13. 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 ...

  14. 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.

  15. Modeling chloride movement in the alluvial aquifer at the Rocky Mountain Arsenal, Colorado

    Science.gov (United States)

    Konikow, Leonard F.

    1977-01-01

    A solute-transport model that can be used to predict the movement of dissolved chemicals in flowing ground water was applied to a problem of ground-water contamination at the Rocky Mountain Arsenal, near Denver, Colo. The model couples a finite-difference solution to the ground-water flow equation with the method-of-characteristics solution to the solute-transport equation. From 1943 to 1956 liquid industrial wastes containing high chloride concentrations were disposed into unlined ponds at the Arsenal. Wastes seeped out of the unlined disposal ponds and spread for many square miles in the underlying shallow alluvial aquifer. Since 1956 disposal has been into an asphalt-lined reservoir, which contributed to a decline in ground-water contamination by 1972. The simulation model quantitatively integrated the effects of the major factors that controlled changes in chloride concentrations and accurately reproduced the 30-year history of chloride ground-water contamination. Analysis of the simulation results indicates that the geologic framework of the area markedly restricted the transport and dispersion of dissolved chemicals in the alluvium. Dilution, from irrigation recharge and seepage from unlined canals, was an important factor in reducing the level of chloride concentrations downgradient from the Arsenal. Similarly, recharge of uncontaminated water from the unlined ponds since 1956 has helped to dilute and flush the contaminated ground water.

  16. 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.

  17. Integrated ERT and Magnetic Surveys in a Mineralization Zone in Erkowit - Red Sea State - Sudan

    Directory of Open Access Journals (Sweden)

    K.M. Kheiralla

    2015-01-01

    Full Text Available The present study focus on integrated geophysical surveys carried out in the mineralization zone in Erkowit region, Eastern Sudan to determine the extensions of the potential ore deposits on the topographically high hilly area and under the cover of alluvium along the nearby wadi and to locate other occurrences if any. The magnetic method (MAG and the electrical resistivity tomography (ERT were employed for the survey. Eleven traverses were aligned approximately at right angles to the general strike of the rock formations. The disseminated sulfides are located on the alteration shear zone which is composed of granitic and dioritic highly ferruginated rock occupying the southwestern and central parts of the area, this was confirmed using thin and polished sections mineralogical analysis. The magnetic data indicates low magnetic values for wadi sedimentary deposits in its southern part of the area, and high anomalies which are suspected as gossans due to magnetite formed during wall rock alteration consequent to mineralization. The significant ERT imagesdefinelow resistivity zone as traced as sheared zones which may associated with the main loci of ore deposition. The study designates that correlation of magnetic and ERT anomalies with lithology are extremely useful in mineral exploration due to variations in some specific physical properties of rocks.

  18. 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.

  19. Influence of geochemical processes on hydrochemistry and irrigation suitability of groundwater in part of semi-arid Deccan Plateau, India

    Science.gov (United States)

    Vasu, Duraisamy; Singh, Surendra Kumar; Tiwary, Pramod; Sahu, Nisha; Ray, Sanjay Kumar; Butte, Pravin; Duraisami, Veppangadu Perumal

    2017-02-01

    Major ion geochemistry was used to characterise the chemical composition of groundwater in part of semi-arid Deccan plateau region to understand the geochemical evolution and to evaluate the groundwater quality for irrigation. The study area comprises peninsular gneissic complex of Archean age, younger granites and basaltic alluvium. Forty-nine georeferenced groundwater samples were collected and analysed for major ions. The ionic sequence based on relative proportions was Na+ > Mg2+ > Ca2+ > SO4 2- > HCO3 - > Cl- > CO3 2- > BO3 3- > K+. High Na+, Mg2+ and Ca2+ were generally associated with basaltic alluvial formation, whereas pH, electrical conductivity (EC) and total dissolved salts (TDS) were found to be higher in granitic formations. High standard deviation for EC, TDS, Na+, Ca2+ and Mg2+ indicated the dispersion of ionic concentration throughout the study area. Four major hydrochemical facies identified were Na-Mg-HCO3 type; Mg-Na-HCO3 type; Na-Mg-Ca-SO4 and Mg-Na-Ca-SO4 type. The graphical plots indicated that the groundwater chemistry was influenced by rock-water interaction, silicate weathering and reverse ion exchange. Sodium-dominated waters might have impeded the hydraulic properties of soils as a result of long-term irrigation.

  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. Calibration of mammoth ( Mammuthus) dispersal into North America using rare earth elements of Plio-Pleistocene mammals from Florida

    Science.gov (United States)

    MacFadden, Bruce J.; Hulbert, Richard C.

    2009-01-01

    The first appearance of mammoth ( Mammuthus) is currently used to define the beginning of the Irvingtonian North American Land Mammal Age at about 1.4 Ma. Thereafter, mammoth fossils are common and widespread in North America until the end of the Pleistocene. In contrast to this generally accepted biochronology, recent reports have asserted that mammoth occurs in late Pliocene (ca. 2.5 Ma) alluvium from the Santa Fe River of northern Florida. The supposedly contemporaneous late Pliocene fossil assemblage from the Santa Fe River that produced the mammoth specimens actually consists of a mixture of diagnostic Blancan (late Pliocene) and late Rancholabrean (latest Pleistocene) species. Fossil bones and teeth of the two mammalian faunas mixed together along the Santa Fe River have significantly different rare earth element (REE) signatures. The REE signatures of mammoth are indistinguishable from those of Rancholabrean mammals, yet they are different from those of diagnostic Blancan vertebrates from these same temporally mixed faunas of the Santa Fe River. Thus, no evidence for late Pliocene mammoth exists in Florida, and mammoth fossils remain reliable biochronological indicators for Irvingtonian and Rancholabrean terrestrial sequences throughout mid- and lower-latitude North America.

  2. 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.

  3. 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.

  4. Crustal structure of the western Indian shield: Model based on regional gravity and magnetic data

    Directory of Open Access Journals (Sweden)

    Suman Kilaru

    2013-11-01

    This study probes the geometry of the different crustal units in terms of density and susceptibility variations in order to decipher the imprints of the major tectonic processes the region has undergone. In order to decipher the crustal geometry of the Gadra–Fatehpur profile, two NW–SE gravity and magnetic profile vertical sections (A–A′ in the south and B–B′ in the north are modelled on the basis of the constraints provided from previous seismic models. The crustal model of the Gadra–Fatehpur profile is composed of alluvium, Tertiary sediments, MIS, Marwar Supergroup, low-density layers (LDLs and the middle–lower crustal layers, with a distinct change in configuration from the southwest to northeast. The Moho dips from SW to NE, the MIS in the SW gives way to the thick pile of the Marwar Supergroup to the NE. The evolution of MIS has been suggested to have occurred as a consequence of delamination of the upper mantle. LDLs are incorporated in Gadra–Fatehpur model. In the SW, LDL (2550 kg/m3 lies below the MIS in the NE, another LDL (2604 kg/m3 is depicted below the mid-crustal layer.

  5. Malakofauna v nivě Jizery (Severní Čechy The mollusc fauna of the Jizera River floodplain (North Bohemia

    Directory of Open Access Journals (Sweden)

    Vojen Ložek

    2013-06-01

    Full Text Available This paper presents a research of floodplain mollusc communities of the Jizera River (the Elbe tributary, North Bohemia, Czech Republic. Altogether, 101 mollusc species (100 species of gastropods, one species of bivalve were recorded at 55 selected sites during previous and recent researches in 1945–1997 and 2002–2009, representing 40% of the total Czech malacofauna. The upper well-preserved stretch of the river hosts a rich forest mollusc fauna with some rare woodland species e.g. Arion intermedius, Cochlodina dubiosa corcontica, Daudebardia brevipes, D. rufa, Vertigo alpestris and Vitrea subrimata. Impoverish assemblages of the lower stretch are represented by some common or open/semi-open country species, because the river flows there through the landscape of an intensive agricultural land use and high settlement density. Despite, the occurrence of 31 rare species (four of them endangered, eight vulnerable, and 19 near threatened was recorded at the upper stretch of the Jizera River alluvium, which provides an important refuge for these mollusc faunas.

  6. 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.

  7. Aquifer tests at the Jackpile-Paguate uranium mine, Pueblo of Laguna, west-central New Mexico

    Science.gov (United States)

    Risser, D.W.; Davis, P.A.; Baldwin, J.A.; McaAda, D.P.

    1984-01-01

    The transmissivity of the Jackpile sandstone bed in the Brushy Basin Shale Member of the Morrison Formation, west-central New Mexico, was determined to be 24 sq ft/day at well M2 and 47 sq ft/day at well M3 from constant-discharge aquifer tests conducted at the Jackpile-Paguate Uranium Mine. The storage coefficient of the Jackpile sandstone bed was estimated to be 0.00018 at well M2 and 0.00029 at well M3 from the same tests. An aquifer test conducted at well M21 indicated the transmissivity of the Jackpile sandstone bed was 2.0 sq ft/day and the storage coefficient was 0.00002. The transmissivity of an unnamed sandstone bed in the Brushy Basin Shale Member of the Morrison Formation was estimated from ' slug-test ' results to be about 20 sq ft/day. Water levels in this sandstone probably did not change due to pumping from the overlying Jackpile sandstone bed for 88 hours at an average discharge of 15.3 gallons/min. A constant discharge aquifer test at well M4C indicated that the transmissivity of the alluvium at this location was about 430 sq ft/day. Water levels in the underlying Jackpile sandstone bed began declining within 15 minutes after withdrawals of groundwater from the alluvial aquifer began. (USGS)

  8. Water resources on the Pueblo of Laguna, west-central New Mexico

    Science.gov (United States)

    Risser, D.W.; Lyford, F.P.

    1983-01-01

    This study evaluates the quality and quantity of water available on the Pueblo of Laguna, New Mexico. Groundwater for public supply occurs in the valley fill along the Rio San Jose, in the Paguate and Encinal areas, and possibly in the northern part of the Sedillo Grant. The valley fill in the Rio San Jose will supply 50 to 450 gallons per minute of potable water to properly constructed wells. In the alluvium along Rio Paguate, additional development of as much as 250 gallons per minute is possible. Groundwater for irrigation is restricted by available yields and quality to the valley fill along the Rio San Jose and possibly the western part of the Major 's Ranch area. In the Rio San Jose valley yields of 50 to 450 gallons per minute of water containing 500 to 3,000 milligrams per liter are possible. Digital-model simulations of the valley-fill aquifer west of the Village of Laguna show a potential salvage of as much as 900 acre-feet per year of evapotranspiration losses if water levels are lowered. Model studies also indicate that the winter flow of the Rio San Jose could be used to recharge groundwater stored in the valley. (USGS)

  9. 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.

  10. Data Validation Package, December 2015, Groundwater Sampling at the Bluewater, New Mexico, Disposal Site, September 2016

    Energy Technology Data Exchange (ETDEWEB)

    Tsosie, Bernadette [U. S. Department of Energy, Washington, DC (United States). Office of Legacy Management; Johnson, Richard [Navarro Research and Engineering, Oak Ridge, TN (United States)

    2016-09-01

    Groundwater samples were collected from monitoring wells at the Bluewater, New Mexico, Disposal Site to monitor groundwater contaminants as specified in the 1997 Long-Term Surveillance Plan for the DOE Bluewater (UMTRCA Title II) Disposal Site Near Grants, New Mexico (LTSP). Sampling and analyses were conducted as specified in the Sampling and Analysis Plan for U.S. Department of Energy Office of Legacy Management Sites (LMS/PRO/S04351, continually updated). A duplicate sample was collected from location HMC-951. Alluvium wells are completed in the alluvial sediments in the former channel of the Rio San Jose, which was covered by basalt lava flows known as the El Malpais, and are identified by the suffix (M). Bedrock wells are completed in the San Andres Limestone/Glorieta Sandstone hydrologic unit (San Andres aquifer) and are identified by the suffix (SG). Wells HMC-951 and OBS-3 are also completed in the San Andres aquifer. The LTSP requires monitoring for molybdenum, selenium, uranium, and polychlorinated biphenyls (PCBs); PCB monitoring occurs only during November sampling events. This event included sampling for an expanded list of analytes to characterize the site aquifers and to support a regional groundwater investigation being conducted by the New Mexico Environment Department.

  11. Receiver Function Analysis of Strong-motion Stations in Kaohsiung-Pingtung area, Taiwan

    Science.gov (United States)

    Lin, Che-Min; Wen, Kuo-Liang; Kuo, Chun-Hsiang; Huang, Jyun-Yan

    2016-04-01

    The Kaohsiung City and Pingtung County are located in southern Taiwan and bounded on the west side by several active faults. The shallow velocity structure of thick alluvium basin in this area should be delineated to understand the seismic site effect of strong ground motion. Receiver Function (RF) is a conventional technique for studying the structure of the crust and upper mantle beneath the seismometer. But, the RF analysis of high-frequency acceleration seismograms is also proved to be feasible for estimating shallow structures recently. This study applied the RF technique on the Strong-motion records of almost one-hundred TSMIP stations in Kaohsiung-Pingtung area to estimate the shallow shear-wave velocity structures. The averaged RFs of all stations exhibit the obvious variation because of the different geologies and site conditions. After the forward modeling of RFs based on the Genetic Algorithms (GA) searching, the shallow shear-wave velocity structures beneath all the strong-motion stations in the Kaohsiung-Pingtung area were estimated to delineate the iso-depth contour maps of the main formation interfaces and a preliminary shallow 3D velocity model.

  12. 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.

  13. Behaviour of a small sedimentary volcanic aquifer receiving irrigation return flows: La Aldea, Gran Canaria, Canary Islands (Spain)

    Science.gov (United States)

    Cruz-Fuentes, T.; Heredia, J.; Cabrera, M. C.; Custodio, E.

    2014-06-01

    In many arid and semi-arid areas, intensive cultivation is practiced despite water commonly being a limiting factor. Often, irrigation water is from local aquifers or imported from out-of-area aquifers and surface reservoirs. Irrigation return flows become a significant local recharge source, but they may deteriorate aquifer water quality. La Aldea valley, located in the western sector of Gran Canaria Island (Atlantic Ocean), is a coastal, half-closed depression in altered, low-permeability volcanics with alluvium in the gullies and scree deposits over a large part of the area. This area is intensively cultivated. Irrigation water comes from reservoirs upstream and is supplemented (average 30 %) by local groundwater; supplementation goes up to 70 % in dry years, in which groundwater reserves are used up to exhaustion if the dry period persists. Thus, La Aldea aquifer is key to the water-supply system, whose recharge is mostly from return irrigation flows and the scarce local rainfall recharge on the scree formations, conveyed to the gully deposits. To quantify the hydrogeological conceptual model and check data coherence, a simplified numerical model has been constructed, which can be used as a tool to help in water management.

  14. A Non-Electrostatic Surface Complexation Approach to Modeling Radionuclide Migration at the Nevada Test Site: II. Aluminosilicates

    Energy Technology Data Exchange (ETDEWEB)

    Zavarin, M; Bruton, C J

    2004-12-16

    rare earth and actinide ions examined here. Ion exchange is effectively suppressed due to aqueous speciation at high pH which tends to result in neutral or negatively charged aqueous species that are less likely to undergo ion exchange. The resulting set of average NEM and Vanselow IE constants provides a consistent set of constants for use in reactive transport simulations. The average NEM and Vanselow IE constants were used to predict single-mineral K{sub d}s under conditions similar to K{sub d} measurements reported by the Yucca Mountain site characterization program. In most cases, predicted Kds were consistent with measured K{sub d}s. In some cases, differences could be explained by surface area, mineralogy, or redox state. The NEM and Vanselow IE constants described here are an attempt to arrive at a consistent simplified database of reaction constants to be used in reactive transport simulations in chemically and mineralogically heterogeneous environments. The accuracy of these reaction constants is limited by the quality and quantity of available sorption data and the limitations of the NEM and Vanselow IE approach used. The reactivity and accessibility of natural minerals is complicated and cannot be assumed to behave ideally. Thus, the validity of the NEM and Vanselow IE constants must always be examined for the sediment of interest. For example, Triay et al. (1997) suggested that the weak sorption of Np(V) on tuff containing small amounts of hematite may indicate that the iron oxide mineral is passivated. Thus, the reactive surface area of hematite in these samples may be lower than expected. On the other hand, a limited comparison of NEM and Vanselow IE constants determined here and K{sub d}s reported by Wolfsberg (1978) for alluvium from Frenchman Flat, NTS, suggests that the reaction constants and reactive surface areas developed here would provide a conservative estimate of radionuclide retardation in Frenchman Flat alluvium.

  15. Evidence for Active Westward Tilting of Fortymile Wash, Nye County, Nevada

    Science.gov (United States)

    McKague, H. L.; Sims, D. W.; Waiting, D. J.

    2006-12-01

    Fortymile Wash is located east and south of a potential high-level nuclear waste repository at Yucca Mountain, Nevada. Several lines of evidence suggest that this may be an area of active westward tilting associated with the continued development of Crater Flat basin and slip on the Bare Mountain normal fault. Near the southern end of Busted Butte, the incised channel of Fortymile Wash changes trend downgradient from south to south-southwest. Further southward, the incised main channel grades to a divergent distributary channel system that shows evidence of increasingly westward tilt. Viewed in profiles oriented normal to the incised channel and across the Fortymile Wash distributary system, topographic elevation of the western margin of the fan decreases southward, resulting in the elevation of the western margin of Fortymile Basin being as much as 18 m [59 ft] lower than the channel system on the eastern fan margin. Mapping of the surficial deposits within the distributary channel system (Pelletier, et al., 2005; Geophy. Res. Ltr., Vol. 32) may be interpreted to show a westward shift (downslope) of the locus of erosional activity toward the topographically lower western fan margin. Most of the older alluvium (Qa3 {86±40-16 ka}) has been eroded from the eastern portion, while incipient incision into the older alluvium is occurring on the western side of the distributary channel system. The results from level-line benchmark surveys (Gilmore, 1992; USGS OFR 92- 450) from 1915 and 1984 show gradual and systematic elevation changes east of the Bare Mountain fault to just east of Amargosa City, Nevada, where a step-like increase occurs. The level-line surveys are near and along the path of U.S. Highway 95, which traverses the distributary channel system of the Fortymile Wash alluvial fan in the southern portion of the Fortymile Wash basin. These lines of evidence indicate disequilibrium in the channel system that would result from active westward tilting of the

  16. Late Quaternary extraglacial cold-climate deposits in low and mid-altitude Tasmania and their climatic implications

    Science.gov (United States)

    McIntosh, P. D.; Eberhard, R.; Slee, A.; Moss, P.; Price, D. M.; Donaldson, P.; Doyle, R.; Martins, J.

    2012-12-01

    Many Tasmanian deposits previously described as 'periglacial' have been described in more detail, re-interpreted and dated. We suggest that 'periglacial' has little meaning when applied locally and the term 'relict cold-climate deposits' is more appropriate. In this paper we examine the origin and age of relict cold-climate slope deposits, fan alluvium and aeolian sediments in Tasmania, and infer the conditions under which they accumulated. Fan alluvium dating from the penultimate Glacial (OIS 6) and capped by a prominent palaeosol deduced to date to the Last Interglacial (OIS 5e) is present at Woodstock, south of Hobart. Many fan deposits formed before 40 ka or in a period c. 30-23 ka; only a few deposits date to the Last Glacial Maximum in Tasmania, which is defined as spanning the period 23.5-17.5 ka. Slope deposits indicate widespread instability down to present-day sea level throughout the Last Glacial, probably as a result of freeze-thaw in a sparsely vegetated landscape. Layered fine gravel and coarse sand colluvial deposits resembling grèzes litées, produced both by dry deposition and by the action of water, are locally common where jointed siltstone bedrock outcrops. These deposits occur from altitudes of 500 m to near sea level and also in caves and must have formed under sparse vegetation cover, probably by freeze-thaw in extremely dry conditions. They have been radiocarbon dated from 35 to 17.5 cal. ka. Relict dunes and sandsheets are widespread at the margin of the Bassian Plain that once provided a land bridge between Tasmania and the mainland. They are also found in western Tasmania and in areas of inland southern Tasmania that now support wet eucalypt forest and rainforest and receive mean annual rainfall > 1500 mm. In the south they have been dated > 87.5-19 ka and attest to a long period of semi-arid climate in an area extending well to the west and south of the present semiarid zone. We deduce that during most of the Last Glacial anticyclones

  17. 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

  18. 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

  19. 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

  20. Temporal and spatial constraints on the evolution of a Rio Grande rift sub-basin, Guadalupe Mountain area, northern New Mexico

    Science.gov (United States)

    Thompson, R. A.; Turner, K. J.; Cosca, M. A.; Drenth, B.; Hudson, M. R.; Lee, J.

    2013-12-01

    The Taos Plateau volcanic field (TPVF) in the southern San Luis Valley of northern New Mexico is the most voluminous of the predominantly basaltic Neogene (6-1 Ma) volcanic fields of the Rio Grande rift. Volcanic deposits of the TPVF are intercalated with alluvial deposits of the Santa Fe Group and compose the N-S-trending San Luis Basin, the largest basin of the northern rift (13,500 km2 in area). Pliocene volcanic rocks of the Guadalupe Mountain area of northern New Mexico are underlain by the southern end of one of the larger sub-basins of the San Luis Valley, the Sunshine sub-basin (~ 450 km2 in area) juxtaposed against the down-to-west frontal fault of the Precambrian-cored Sangre de Cristo Range. The sub-basin plunges northward and extends to near the Colorado-New Mexico border. The western margin (~15 km west of the Sangre de Cristo fault) is constrained by outcrops of Oligocene to Miocene volcanic rocks of the Latir volcanic field, interpreted here as a broad pre-Pliocene intra-rift platform underlying much of the northern TPVF. The southern sub-basin border is derived, in part, from modeling of gravity and aeromagnetic data and is interpreted as a subsurface extension of this intra-rift platform that extends southeastward to nearly the Sangre de Cristo range front. Broadly coincident with this subsurface basement high is the northwest-trending, curvilinear terminus of the down-to-northeast Red River fault zone. South of the gravity high, basin-fill alluvium and ~3.84 Ma Servilleta basalt lava flows thicken along a poorly exposed, down-to-south, basin-bounding fault of the northern Taos graben, the largest of the San Luis Valley sub-basins. The uppermost, western sub-basin fill is exposed along steep canyon walls near the confluence of the Rio Grande and the Red River. Unconformity-bound, lava flow packages are intercalated with paleo Red River fan alluvium and define six eruptive sequences in the Guadalupe Mountain area: (1) Guadalupe Mtn. lavas (dacite ~5

  1. 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).

  2. 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

  3. Hydrologic setting and geochemical characterization of free-phase hydrocarbons in the alluvial aquifer at Mandan, North Dakota, November 2000

    Science.gov (United States)

    Hostettler, Frances D.; Rostad, Colleen E.; Kvenvolden, Keith A.; Delin, Geoffrey N.; Putnam, Larry D.; Kolak, Jonathan J.; Chaplin, Brain P.; Schaap, Bryan D.

    2001-01-01

    Free-phase hydrocarbons are present in the alluvial aquifer at Mandan, North Dakota. A large contaminant body of the hydrocarbons [light nonaqueous phase liquid (LNAPL)] floats on the water table about 20 feet below land surface. The main LNAPL body is about 6 feet thick, and the areal extent is about 657,000 square feet. A study was conducted to describe the hydrologic setting and characterize the geochemical composition of the free-phase hydrocarbons in the alluvial aquifer. Most of the study area is underlain by alluvium of the Heart River Valley that ranges in thickness from about 25 to 109 feet. The alluvium can be divided into three stratigraphic units--silty clay, silty sand, and sand--and is underlain by shales and sandstones. Monitoring wells were installed prior to this study, to an average depth of about 29 feet. Regional ground-water flow in the Heart River aquifer generally may be from west-northwest to east-southeast and is influenced by hydraulic connections to the river. Hydraulic connections also are probable between the aquifer and the Missouri River. Ground-water flow across the north boundary of the aquifer is minimal because of adjacent shales and sandstones of relatively low permeability. Recharge occurs from infiltration of precipitation and is spatially variable depending on the thickness of overlying clays and silts. Although the general water-table gradient may be from west-northwest to east-southeast, the flow directions can vary depending on the river stage and recharge events. Any movement of the LNAPL is influenced by the gradients created by changes in water-level altitudes. LNAPL samples were collected from monitoring wells using dedicated bailers. The samples were transferred to glass containers, stored in the dark, and refrigerated before shipment for analysis by a variety of analytical techniques. For comparison purposes, reference-fuel samples provided by the refinery in Mandan also were analyzed. These reference-fuel samples

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. Numerical modelling of groundwater flow to understand the impacts of pumping on arsenic migration in the aquifer of North Bengal Plain

    Science.gov (United States)

    Sikdar, P. K.; Chakraborty, Surajit

    2017-03-01

    In this paper, numerical simulations of regional-scale groundwater flow of North Bengal Plain have been carried out with special emphasis on the arsenic (As)-rich alluvium filled gap between the Rajmahal hills on the west and the Garo hills on the east. The proposed concern of this modelling arose from development that has led to large water table declines in the urban area of English Bazar block, Malda district, West Bengal and possible transport of As in the near future from the adjacent As-polluted aquifer. Groundwater occurs under unconfined condition in a thick zone of saturation within the Quaternary alluvial sediments. Modelling indicates that current pumping has significantly changed the groundwater flowpaths from pre-development condition. At the present pumping rate, the pumping wells of the urban area may remain uncontaminated till the next 25 yrs, considering only pure advection of water but some water from the As-polluted zone may enter wells by 50 yrs. But geochemical and other processes such as adsorption, precipitation, redox reaction and microbial activity may significantly retard the predicted rate by advective transport. In the rural areas, majority of the water pumped from the aquifer is for irrigation, which is continuously re-applied on the surface. The near-vertical nature of the flowpaths indicates that, where As is present or released at shallow depths, it will continue to occur in pumping wells. Modelling also indicates that placing all the pumping wells at depths below 100 m may not provide As-free water permanently.

  12. Quantifying natural source mercury emissions from the Ivanhoe Mining District, north-central Nevada, USA

    Science.gov (United States)

    Engle, Mark A.; Gustin, Mae Sexauer; Zhang, Hong

    In order to assess the importance of mercury emissions from naturally enriched sources relative to anthropogenic point sources, data must be collected that characterizes mercury emissions from representative areas and quantifies the influence of various environmental parameters that control emissions. With this information, we will be able to scale up natural source emissions to regional areas. In this study in situ mercury emission measurements were used, along with data from laboratory studies and statistical analysis, to scale up mercury emissions for the naturally enriched Ivanhoe Mining District, Nevada. Results from stepwise multi-variate regression analysis indicated that lithology, soil mercury concentration, and distance from the nearest fault were the most important factors controlling mercury flux. Field and lab experiments demonstrated that light and precipitation enhanced mercury emissions from alluvium with background mercury concentrations. Diel mercury emissions followed a Gaussian distribution. The Gaussian distribution was used to calculate an average daily emission for each lithologic unit, which were then used to calculate an average flux for the entire area of 17.1 ng Hg m -2 h -1. An annual emission of ˜8.7×10 4 g of mercury to the atmosphere was calculated for the 586 km 2 area. The bulk of the Hg released into the atmosphere from the district (˜89%) is from naturally enriched non-point sources and ˜11% is emitted from areas of anthropogenic disturbance where mercury was mined. Mercury emissions from this area exceed the natural emission factor applied to mercury rich belts of the world (1.5 ng m -2 h -1) by an order of magnitude.

  13. Geomorphic and Ecological Issues in Removal of Sediment-Filled Dams in the California Coast Ranges (Invited)

    Science.gov (United States)

    Kondolf, G. M.; Oreilly, C.

    2010-12-01

    Water-supply reservoirs in the actively eroding California Coast Ranges are vulnerable to sediment filling, thus creating obsolete impounding dams (Minear & Kondolf 2009). Once full of sediment, there is more impetus to remove dams for public safety and fish passage, but managing accumulated sediments becomes a dominant issue in dam removal planning. We analyzed the planning process and sediment management analyses for five dams, all of which have important ecological resources but whose dam removal options are constrained by potential impacts to downstream urban populations. Ringe Dam on Malibu Ck, Matilija Dam on the Ventura River, Searsville Dam on San Francisquito Ck, and Upper York Creek Dam on York Ck cut off important habitat for anadromous steelhead trout (Oncorhynchus mykiss). San Clemente Dam on the Carmel River has a working fish ladder, but only some of the migratory steelhead use it. By virtue of having filled with sediment, all five dams are at greater risk of seismic failure. San Clemente Dam is at greater risk because its foundation is on alluvium (not bedrock), and the poor-quality concrete in Matilija Dam is deteriorating from an akali-aggregate reaction. Simply removing the dams and allowing accumulated sediments to be transported downstream is not an option because all these rivers have extremely expensive houses along downstream banks and floodplains, so that allowing the downstream channel to aggrade with dam-dervied sediments could expose agencies to liability for future flood losses. Analyses of potential sediment transport have been based mostly on application of tractive force models, and have supported management responses ranging from in-situ stabilization (San Clemente and Matilija) to removal of stored sediment (York) to annual dredging to maintain capacity and prevent sediment passing over the dam (proposed for Searsville).

  14. Analecta of structures formed during the 28 June 1992 Landers-Big Bear, California earthquake sequence (including maps of shear zones, belts of shear zones, tectonic ridge, duplex en echelon fault, fault elements, and thrusts in restraining steps)

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, A.M.; Johnson, N.A.; Johnson, K.M.; Wei, W. [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth and Atmospheric Sciences; Fleming, R.W. [Geological Survey, Denver, CO (United States); Cruikshank, K.M. [Portland State Univ., OR (United States). Dept. of Geology; Martosudarmo, S.Y. [BPP Technologi, Jakarta (Indonesia)

    1997-12-31

    The June 28, 1992, M{sub s} 7.5 earthquake at Landers, California, which occurred about 10 km north of the community of Yucca Valley, California, produced spectacular ground rupturing more than 80 km in length (Hough and others, 1993). The ground rupturing, which was dominated by right-lateral shearing, extended along at least four distinct faults arranged broadly en echelon. The faults were connected through wide transfer zones by stepovers, consisting of right-lateral fault zones and tension cracks. The Landers earthquakes occurred in the desert of southeastern California, where details of ruptures were well preserved, and patterns of rupturing were generally unaffected by urbanization. The structures were varied and well-displayed and, because the differential displacements were so large, spectacular. The scarcity of vegetation, the aridity of the area, the compactness of the alluvium and bedrock, and the relative isotropy and brittleness of surficial materials collaborated to provide a marvelous visual record of the character of the deformation zones. The authors present a series of analecta -- that is, verbal clips or snippets -- dealing with a variety of structures, including belts of shear zones, segmentation of ruptures, rotating fault block, en echelon fault zones, releasing duplex structures, spines, and ramps. All of these structures are documented with detailed maps in text figures or in plates (in pocket). The purpose is to describe the structures and to present an understanding of the mechanics of their formation. Hence, most descriptions focus on structures where the authors have information on differential displacements as well as spatial data on the position and orientation of fractures.

  15. Enhanced stability of steep channel beds to mass failure and debris flow initiation

    Science.gov (United States)

    Prancevic, J.; Lamb, M. P.; Ayoub, F.; Venditti, J. G.

    2015-12-01

    Debris flows dominate bedrock erosion and sediment transport in very steep mountain channels, and are often initiated from failure of channel-bed alluvium during storms. While several theoretical models exist to predict mass failures, few have been tested because observations of in-channel bed failures are extremely limited. To fill this gap in our understanding, we performed laboratory flume experiments to identify the conditions necessary to initiate bed failures in non-cohesive sediment of different sizes (D = 0.7 mm to 15 mm) on steep channel-bed slopes (S = 0.45 to 0.93) and in the presence of water flow. In beds composed of sand, failures occurred under sub-saturated conditions on steep bed slopes (S > 0.5) and under super-saturated conditions at lower slopes. In beds of gravel, however, failures occurred only under super-saturated conditions at all tested slopes, even those approaching the dry angle of repose. Consistent with theoretical models, mass failures under super-saturated conditions initiated along a failure plane approximately one grain-diameter below the bed surface, whereas the failure plane was located near the base of the bed under sub-saturated conditions. However, all experimental beds were more stable than predicted by 1-D infinite-slope stability models. In partially saturated sand, enhanced stability appears to result from suction stress. Enhanced stability in gravel may result from turbulent energy losses in pores or increased granular friction for failures that are shallow with respect to grain size. These grain-size dependent effects are not currently included in stability models for non-cohesive sediment, and they may help to explain better the timing and location of debris flow occurrence.

  16. 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.

  17. Geologic map of the eastern half of the Vail 30' x 60' quadrangle, Eagle, Summit, and Grand Counties, Colorado

    Science.gov (United States)

    Kellogg, Karl S.; Shroba, Ralph R.; Premo, Wayne R.; Bryant, Bruce

    2011-01-01

    Recent mapping and geochronologic studies for the eastern half of the Vail 1:100,000-scale quadrangle have significantly improved our understanding of (1) Paleoproterozoic history of the basement rocks of the Gore Range and Williams Fork Mountains (western margin of the Front Range), (2) the Late Paleozoic history of the Gore fault system, (3) Laramide contractional tectonism, including deformation along the Gore fault and Williams Range thrust, (4) Oligocene and younger extensional history of the Blue River half graben (The northern extent of the Rio Grande rift), and (5) late Neogene and Quaternary surficial history. The recently active Gilman mining district, a major producer of zinc and lead, is in the southwestern corner of the map area. Marine sediments and mafic to felsic volcanic rocks deposited between about 1,740 and 1,780 m.y. were generally metamorphosed to amphibolite grade and intruded and deformed by mostly calc-alkalic granitic rocks during an orogenic episode that lasted about 110 m.y. The distribution of well-studied Upper Cambrian to thick Upper Cretaceous platform sediments is now greatly improved, which allows a better definition of the late Paleozoic uplift, erosion, and flanking sedimentation of the ancestral Front Range. Detailed mapping has also better defined the geometry of Late Cretaceous to early Tertiary Laramide deformation along both the Gore fault system and Williams Range thrust, as well as increased understanding of the details of mostly Neogene extension along the Blue River normal fault system (the western margin of the Blue River half graben). Scarps along the latter fault system indicate movement may be as young as Holocene. Detailed mapping of surficial deposits has defined and described (1) six ages of terrace alluvium, (2) three general ages of landslides, (3) glacial and periglacial deposits, and (4) fan, pediment, talus, and debris-flow deposits.

  18. 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.

  19. Estimation of hydraulic characteristics in the Santa Fe Group aquifer system using computer simulations of river and drain pulses in the Rio Bravo study area, near Albuquerque, New Mexico

    Science.gov (United States)

    Roark, D.M.

    2001-01-01

    In 1997, the U.S. Geological Survey conducted a hydrologic investigation of the surface-water/ground-water interaction of the Rio Grande and the surrounding alluvium and the Santa Fe Group aquifer system in an area near the Rio Bravo Bridge, south of Albu- querque, New Mexico. A set of existing wells and new wells were instrumented to monitor water levels in a section perpendicular to the Rio Grande on the east side of the river. Equipment to measure stream stage was installed at two sites--on the Albuquerque Riverside Drain and on the Rio Grande. A short-duration river pulse and a long-duration river pulse were used to stress the ground-water system while the changes in water levels were monitored. A ground- water flow-model simulation using the principle of superposition was used to estimate the hydraulic characteristics of the local ground-water system. Simulated horizontal hydraulic conductivities varied from 0.03 to 100 feet per day, and vertical hydraulic conductivities varied from 1.5 x 10-6 to 0.01 foot per day. The specific yield of layer 1 was estimated to be 0.3. Specific storage for layers 2 through 11 was 1.0 x 10-6. Water entering the model from the river along a 300-foot-wide cross section during simulation of the short-duration pulse averaged 7.46 x 10-3 cubic foot per second and during the long-duration pulse was 1.66 x 10-3 cubic foot per second. The average flux from the model to the drain during the short-duration pulse was 3.18 x 10-3 cubic foot per second. The average flux for the long-duration pulse was 7.14 x 10-3 cubic foot per second from the drain to the model.

  20. Chronic methyl mercury poisoning may trigger endemic pemphigus foliaceus "fogo selvagem".

    Science.gov (United States)

    Robledo, Mary Ann

    2012-01-01

    In endemic pemphigus foliaceus (EPF) or "fogo selvagem" the epidemiological evidence shows that all the described outbreaks occur on the banks of rivers where there is mercury contamination from alluvium gold mining and deforestation. Pathophysiological evidence shows a similarity to pemphigus induced by sulphydryl (SH-) drugs that act by denaturing cadherins at the desmosomal level, which are the pemphigus antigens. The sulfhydryl radical (SH-) call also thiol or mercaptans from the SH-drugs, act at the level of SH-groups of cystein as would the methyl mercury from the contaminated animals and fish in the diet of humans from endemic areas of pemphigus foliaceus. The methyl mercury would join the SH-groups from the cysteines amino acids from cadherin proteins in the skin. The autoimmune disease would only be triggered in genetically susceptible individuals with human leukocyte antigen HLA-DRB 1 haplotypes, just as Brown-Norway (BN) rats which are susceptible to develop Th2-dependent autoimmunity induced by metals. Immunological evidence from all the seroepidemiological studies could also be explained by binding mechanism of the methyl mercury to the SH-groups from the cysteines in the desmosomal cadherins proteins. The conclusion is that chronic methyl mercury poisoning is the most likely trigger of endemic pemphigus foliaceus "fogo selvagem". To reduce the contamination of methyl mercury in the animals of the polluted rivers is pertinent to the design of campaigns and education programs with the population. Implement reforestation and biological control measures like phytoremediation technologies using decontaminant plants to decrease the methylation, and the process of biomagnifications of the methyl mercury in the Latin-America EPF foci.

  1. Study of Subsidence and Earthquake Swarms in the Western Pakistan

    Directory of Open Access Journals (Sweden)

    Jingqiu Huang

    2016-11-01

    Full Text Available In recent years, the Quetta Valley and surrounding areas have experienced unprecedented levels of subsidence, which has been attributed mainly to groundwater withdrawal. However, this region is also tectonically active and is home to several regional strike-slip faults, including the north–south striking left-lateral Chaman Fault System. Several large earthquakes have occurred recently in this area, including one deadly Mw 6.4 earthquake that struck on 28 October 2008. This study integrated Interferometric Synthetic Aperture Radar (InSAR results with GPS, gravity, seismic reflection profiles, and earthquake centroid-moment-tensor (CMT data to identify the impact of tectonic and anthropogenic processes on subsidence and earthquake patterns in this region. To detect and map the spatial-temporal features of the processes that led to the surface deformation, this study used two Synthetic Aperture Radar (SAR time series, i.e., 15 Phased Array L-band Synthetic Aperture Radar (PALSAR images acquired by an Advanced Land Observing Satellite (ALOS from 2006–2011 and 40 Environmental Satellite (ENVISAT Advanced Synthetic Aperture Radar (ASAR images spanning 2003–2010. A Small Baseline Subset (SBAS technique was used to investigate surface deformation. Five seismic lines totaling ~60 km, acquired in 2003, were used to map the blind thrust faults beneath a Quaternary alluvium layer. The median filtered SBAS-InSAR average velocity profile supports groundwater withdrawal as the dominant source of subsidence, with some contribution from tectonic subsidence in the Quetta Valley. Results of SBAS-InSAR multi-temporal analysis provide a better explanation for the pre-, co-, and post-seismic displacement pattern caused by the 2008 earthquake swarms across two strike-slip faults.

  2. 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

  3. 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).

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Risks Associated To Present Geomorphologic Processes In The Stemnic (Buda River Basin

    Directory of Open Access Journals (Sweden)

    Bojoagă Ioan

    2015-10-01

    Full Text Available The paper analyses the main geomorphologic processes in the Stemnic (Buda river basin, conditioned by the joint action of several factors, among which are the lithological peculiarities and the nature of superficial deposits, morphometric characteristics, climate, vegetation type and structure, properties of the soil cover etc. The Stemnic river basin with an area of 15662.52 ha is characterized by its elongated shape (the maximum length is of 30.5 km, maximum width of 8.5 km, its relative lithological homogeneity, but also by a variety of superficial deposits (eluvium, diluvium, colluvium and proluvium, alluvium and by a relief energy of significant values between 136 m and 10 m (mean value of 73 m. Under these conditions, study area is characterized by a high degree of susceptibility to the occurrence of geomorphologic risk processes. For the morphometric and morphological analysis, we applied the method of the digital terrain model (DTM with vectorisation of the contour lines on topographic maps with a scale of 1:5,000. In this paper we used indicators that highlight the particular frequency of landslides, especially in the upper and middle sectors, but the rather reduced frequency of deep erosion. Due to the satisfactory coverage of the ground with vegetation, the erosion reaction is differentiated, as it depends on the use of the land and the concentration of liquid flow on the slopes. Consequently, landslides of different ages, types and forms hold large surfaces in the basin (approx. 8%, while surface erosion affects most areas of the slopes, but with different intensities depending on their use and on agricultural technologies.

  9. 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.

  10. 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.

  11. 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.

  12. Dissolved organic matter dynamics in streams of intermittent flow - linkages with ecohydrologic processes from pool to catchment in northern Australia

    Science.gov (United States)

    Grierson, Pauline; Siebers, Andre; Skrzypek, Grzegorz; Fellman, Jason; Pettit, Neil; Dogramaci, Shawan

    2015-04-01

    Changes in both the frequency and intensity of flood-drought cycles of intermittent streams, either through changing climate or anthropogenic management, may have significant impacts on stream functioning. However, little is known about how and to what extent the quantity and composition of dissolved organic matter (DOM) changes during inter-flood periods and how this relates to stream hydrology, particularly of intermittent rivers. We hypothesised that with increasing time since flooding, controls on stream biogeochemical processes transition from predominantly hydrological to more local scale environmental factors. We also argue that in strongly seasonal and oligotrophic regions, such as those of the tropical northwest of Australia, groundwater inputs of old DOC may increase the bioavailability of stream organic matter. We used δ18O and δ2H values of surface water and groundwater in the alluvium (AW) together with DOM fluorescence excitation-emission spectroscopy and radiocarbon dating to (i) characterise DOM and (ii) assess the relative importance of autochthonous versus allochthonous sources among pools according to how connected they are to groundwater. Our findings show that as streams increase in size and accumulate aromatic DOC from terrestrial plant material, percent bioavailability decreases concomitant with the modernization of the DOC pool. Therefore, rapid biotic uptake of old, bioavailable DOC originating in groundwater springs and the accumulation of modern, terrestrially derived DOC work in opposite directions affecting the dynamics of DOC along fluvial networks. The metabolism of old DOC in small streams is a direct link between terrestrial and aquatic ecosystems but also provides a biogeochemical link between non-contemporary carbon fixation and modern river productivity. Recognition of the hydrologic complexity of dryland rivers is clearly necessary for more effective catchment-scale management strategies that balance an increasing demand for

  13. Anthropogenic effects on soil micromycetes

    Directory of Open Access Journals (Sweden)

    Đukić Dragutin A.

    2007-01-01

    Full Text Available This paper is a synthesis of long-term investigations based on the effect of different authropogenic pollutants (mineral and organic fertilizers, 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 Čačak on smonitza and alluvium soils in field and under 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 Čapek 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 x ha-1 and organic fertilizers stimulated the development of soil fungi, unlike the rate of 150 kg x 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.

  14. 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.

  15. 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.

  16. Modelling of nuclear explosions in hard rock sites

    Energy Technology Data Exchange (ETDEWEB)

    Brunish, W.M.; App, F.N.

    1993-05-01

    This study represents part of a larger effort to systematically model the effects of differing source region properties on ground motion from underground nuclear explosions at the Nevada Test Site. In previous work by the authors the primary emphasis was on alluvium and both saturated and unsaturated tuff. We have attempted to model events on Pahute Mesa, where either the working point medium, or some of the layers above the working point, or both, are hard rock. The complex layering at these sites, however, has prevented us from drawing unambiguous conclusions about modelling hard rock. In order to learn more about the response of hard rock to underground nuclear explosions, we have attempted to model the PILEDRIVER event. PILEDRIVER was fired on June 2, 1966 in the granite stock of Area 15 at the Nevada Test Site. The working point was at a depth of 462.7 m and the yield was determined to be 61 kt. Numerous surface, sub-surface and free-field measurements were made and analyzed by SRI. An attempt was made to determine the contribution of spall to the teleseismic signal, but proved unsuccessful because most of the data from below-shot-level gauges was lost. Nonetheless, there is quite a bit of good quality data from a variety of locations. We have been able to obtain relatively good agreement with the experimental PILEDRIVER waveforms. In order to do so, we had to model the granodiorite as being considerably weaker than ``good quality`` granite, and it had to undergo considerable weakening due to shock damage as well. In addition, the near-surface layers had to be modeled as being weak and compressible and as have a much lower sound speed than the material at depth. The is consistent with a fractured and jointed material at depth, and a weathered material near the surface.

  17. Modelling of nuclear explosions in hard rock sites

    Energy Technology Data Exchange (ETDEWEB)

    Brunish, W.M.; App, F.N.

    1993-01-01

    This study represents part of a larger effort to systematically model the effects of differing source region properties on ground motion from underground nuclear explosions at the Nevada Test Site. In previous work by the authors the primary emphasis was on alluvium and both saturated and unsaturated tuff. We have attempted to model events on Pahute Mesa, where either the working point medium, or some of the layers above the working point, or both, are hard rock. The complex layering at these sites, however, has prevented us from drawing unambiguous conclusions about modelling hard rock. In order to learn more about the response of hard rock to underground nuclear explosions, we have attempted to model the PILEDRIVER event. PILEDRIVER was fired on June 2, 1966 in the granite stock of Area 15 at the Nevada Test Site. The working point was at a depth of 462.7 m and the yield was determined to be 61 kt. Numerous surface, sub-surface and free-field measurements were made and analyzed by SRI. An attempt was made to determine the contribution of spall to the teleseismic signal, but proved unsuccessful because most of the data from below-shot-level gauges was lost. Nonetheless, there is quite a bit of good quality data from a variety of locations. We have been able to obtain relatively good agreement with the experimental PILEDRIVER waveforms. In order to do so, we had to model the granodiorite as being considerably weaker than good quality'' granite, and it had to undergo considerable weakening due to shock damage as well. In addition, the near-surface layers had to be modeled as being weak and compressible and as have a much lower sound speed than the material at depth. The is consistent with a fractured and jointed material at depth, and a weathered material near the surface.

  18. 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.

  19. 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.

  20. Environmental applications of gravity surveying

    Energy Technology Data Exchange (ETDEWEB)

    Barrows, L.J. (Illinois State Univ., Normal, IL (United States)); Nesbit, L.C. (KEMRON Environmental Services, Novi, MI (United States)); Khan, W.A. (Environmental Science Engineering, Phoenix, AZ (United States))

    1994-04-01

    The Allis Park Sanitary Landfill Company developed a new landfill near Onway, Michigan in an area which has glacial alluvium and glacial till overlying limestone. There are several solution karst features in the region and some critics had maintained that a new karst collapse could rupture the liner system and allow escape of leachate into the groundwater. The gravity survey was conducted to determine the extent of any karst development at the site. The first portion of the survey was two profiles over some karst features located about five miles southeast of the proposed landfill. These showed negative gravity anomalies. The survey of the proposed landfill site resulted in a 50 microGal contour map of the area and also showed a negative anomaly. This could be due to either elevation variations on the till to limestone bedrock surface or to karst development within the limestone. Because there was no evidence of historic development of new karst features in the region, the gravity anomaly was not further investigated. In another gravity survey, a large retail department store had been remodeled and extended over an area previously occupied by an auto service center. The removal of a waste oil storage tank (UST) had not been documented and the environmental consultant (KEMRON, Inc.) proposed that a gravity survey be used to find the tank location. This proposal was based on calculations of the gravity effects of a UST. The survey resulted in a four-microGal contour map which showed a couple of anomalies which could be due to a tank or a backfilled tank excavation. During the survey, a store employee identified the previous location of the tank and explained that she had personally witnessed its removal. Based on the employee's eye-witness account of the tank removal and the coincidence of her indicated tank location with one of the gravity anomalies the authors recommended the site be granted clean closure.

  1. Design of the Buffer Structure of Traction Running with a Constant Speed%恒定速度牵引运行的缓冲结构设计

    Institute of Scientific and Technical Information of China (English)

    罗茜; 曾宪任

    2013-01-01

    This paper mainly aimed to study buffer structure design on the traction transport system when the traction transport boundary conditions were 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 could be solved as long as the boundary conditions were input.This provided a quick design basis of buffer structure for most mechanical engineers.%主要研究牵引运输中的缓冲结构设计;通过对给定的牵引运输的边界条件:最大冲击作用力、牵引速度、冲击物最大速度、缓冲结构弹性系数及质量,建立数学模型,求解微分方程,得到问题的解;最后通过MATLAB语言对问题的求解过程进行了程序设计,只要将边界条件输入,就可以解出满足要求的缓冲结构的弹性系数及冲击过程的最大冲击力。给广大机械设计人员提供了快速的缓冲结构设计依据。

  2. 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.

  3. Water resources of Taos County, New Mexico

    Science.gov (United States)

    Garrabrant, Lynn A.

    1993-01-01

    In Taos County, ground water generally is unconfined and moves toward the Rio Grande or perennial streams. Water quality is good except in some areas where water has high values of specific conductance and hardness and contains high concentrations of dissolved solids and fluoride. Most wells are completed in alluvial sediments of Quaternary and Tertiary age in the Costilla Plains. A few wells are completed in basalt of the Taos Plateau and in alluvium of stream channels in the Sangre de Cristo Mountains. Depths to water in wells range from less than 1 to 1,080 feet below land surface. Well yields range from 1 to 3,000 gallons per minute. Water levels in wells in Sunshine Valley dropped 5 to 50 feet between 1955 and 1970. Ground-water irrigation has since declined and water levels have risen. Surface-water records show the county is a net producer of water. The average discharge gained in the Rio Grande as it flows through the county was 271,700 acre-feet per year for water years 1931-89. The highest mean monthly discharge occurs in May or June due to snowmelt runoff. Water quality ranges from good in upstream reaches to fair in lower reaches. Surface water was the source for 93 percent of water withdrawn in 1990, but ground water was used for all public supply, domestic, and industrial purposes. The largest water use is irrigation. About 28,500 acres were irrigated in 1990; alfalfa, native pasture, and planted pasture accounted for 91 percent of this acreage.

  4. The notion of climate-driven strath-terrace production assessed via dissimilar stream-process response to late Quaternary climate

    Science.gov (United States)

    García, Antonio F.; Mahan, Shannon

    2014-01-01

    Previous research results from the Gabilan Mesa are combined with new optically stimulated luminescence (OSL) age estimates and sedimentological analyses with the aim of identifying factors that inhibit climate-driven strath-terrace production, and factors that make possible strath-terrace production independent of climate forcing. The factors are revealed by comparing the morphostratigraphy and OSL age estimates of terraces in the adjacent San Lorenzo Creek and Pancho Rico Creek drainage basins of the central California Coast Ranges. OSL age estimates on San Lorenzo Creek fill-terrace alluvium overlying bedrock at two paleofluvial levels range between 50.5 and 41.3 ka and between 33.4 and 18.2 ka. These OSL age estimates indicate that although the channel of Pancho Rico Creek was degrading at these times, San Lorenzo Creek aggradation was synchronous with previously documented regional, climatically driven aggradation that elsewhere in southern California led to strath production and alluvial deposition. The regional-scale climate forcing events had different effects on San Lorenzo and Pancho Rico Creeks because of the influences of drainage-basin lithology on bedload size and tectonic tilting direction on base-level fall. The Holocene history of channel denudation and strath production of Pancho Rico Creek is also different from that of San Lorenzo Creek, and different from that of many other streams in southern California. After Pancho Rico Creek captured the upper part of the drainage basin of San Lorenzo Creek sometime after 15.5 to 11.7 ka, Pancho Rico Creek has been producing unpaired, erosional strath terraces. The weak, clay rich, fine-grained sedimentary rock underlying Pancho Rico Valley is an ideal substrate in which to form straths. The meandering channel of Pancho Rico Creek produces straths, and weathering resistant, relatively hard bedload introduced by stream capture ensures their preservation as strath terraces.

  5. Early Acheulean technology in the Rietputs Formation, South Africa, dated with cosmogenic nuclides.

    Science.gov (United States)

    Gibbon, Ryan J; Granger, Darryl E; Kuman, Kathleen; Partridge, Timothy C

    2009-02-01

    An absolute dating technique based on the build-up and decay of (26)Al and (10)Be in the mineral quartz provides crucial evidence regarding early Acheulean hominid distribution in South Africa. Cosmogenic nuclide burial dating of an ancient alluvial deposit of the Vaal River (Rietputs Formation) in the western interior of South Africa shows that coarse gravel and sand aggradation there occurred ca 1.57+/-0.22Ma, with individual ages of samples ranging from 1.89+/-0.19 to 1.34+/-0.22Ma. This was followed by aggradation of laminated and cross-bedded fine alluvium at ca 1.26+/-0.10Ma. The Rietputs Formation provides an ideal situation for the use of the cosmogenic nuclide burial dating method, as samples could be obtained from deep mining pits at depths ranging from 7 to 16 meters. Individual dates provide only a minimum age for the stone tool technology preserved within the deposits. Each assemblage represents a time averaged collection. Bifacial tools distributed throughout the coarse gravel and sand unit can be assigned to an early phase of the Acheulean. This is the first absolute radiometric dated evidence for early Acheulean artefacts in South Africa that have been found outside of the early hominid sites of the Gauteng Province. These absolute dates also indicate that handaxe-using hominids inhabited southern Africa as early as their counterparts in East Africa. The simultaneous appearance of the Acheulean in different parts of the continent implies relatively rapid technology development and the widespread use of large cutting tools in the African continent by ca 1.6Ma.

  6. 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.

  7. 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.

  8. 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

  9. Geological observations on large earthquakes along the Himalayan frontal fault near Kathmandu, Nepal

    Science.gov (United States)

    Wesnousky, Steven G.; Kumahara, Yasuhiro; Chamlagain, Deepak; Pierce, Ian K.; Karki, Alina; Gautam, Dipendra

    2017-01-01

    The 2015 Gorkha earthquake produced displacement on the lower half of a shallow decollement that extends 100 km south, and upward from beneath the High Himalaya and Kathmandu to where it breaks the surface to form the trace of the Himalayan Frontal Thrust (HFT), leaving unruptured the shallowest ∼50 km of the decollement. To address the potential of future earthquakes along this section of the HFT, we examine structural, stratigraphic, and radiocarbon relationships in exposures created by emplacement of trenches across the HFT where it has produced scarps in young alluvium at the mouths of major rivers at Tribeni and Bagmati. The Bagmati site is located south of Kathmandu and directly up dip from the Gorkha rupture, whereas the Tribeni site is located ∼200 km to the west and outside the up dip projection of the Gorkha earthquake rupture plane. The most recent rupture at Tribeni occurred 1221-1262 AD to produce a scarp of ∼7 m vertical separation. Vertical separation across the scarp at Bagmati registers ∼10 m, possibly greater, and formed between 1031-1321 AD. The temporal constraints and large displacements allow the interpretation that the two sites separated by ∼200 km each ruptured simultaneously, possibly during 1255 AD, the year of a historically reported earthquake that produced damage in Kathmandu. In light of geodetic data that show ∼20 mm/yr of crustal shortening is occurring across the Himalayan front, the sum of observations is interpreted to suggest that the HFT extending from Tribeni to Bagmati may rupture simultaneously, that the next great earthquake near Kathmandu may rupture an area significantly greater than the section of HFT up dip from the Gorkha earthquake, and that it is prudent to consider that the HFT near Kathmandu is well along in a strain accumulation cycle prior to a great thrust earthquake, most likely much greater than occurred in 2015.

  10. Use of regression-based models to map sensitivity of aquatic resources to atmospheric deposition in Yosemite National Park, USA

    Science.gov (United States)

    Clow, David W.; Nanus, Leora; Huggett, Brian

    2010-01-01

    An abundance of exposed bedrock, sparse soil and vegetation, and fast hydrologic flushing rates make aquatic ecosystems in Yosemite National Park susceptible to nutrient enrichment and episodic acidification due to atmospheric deposition of nitrogen (N) and sulfur (S). In this study, multiple linear regression (MLR) models were created to estimate fall-season nitrate and acid neutralizing capacity (ANC) in surface water in Yosemite wilderness. Input data included estimated winter N deposition, fall-season surface-water chemistry measurements at 52 sites, and basin characteristics derived from geographic information system layers of topography, geology, and vegetation. The MLR models accounted for 84% and 70% of the variance in surface-water nitrate and ANC, respectively. Explanatory variables (and the sign of their coefficients) for nitrate included elevation (positive) and the abundance of neoglacial and talus deposits (positive), unvegetated terrain (positive), alluvium (negative), and riparian (negative) areas in the basins. Explanatory variables for ANC included basin area (positive) and the abundance of metamorphic rocks (positive), unvegetated terrain (negative), water (negative), and winter N deposition (negative) in the basins. The MLR equations were applied to 1407 stream reaches delineated in the National Hydrography Data Set for Yosemite, and maps of predicted surface-water nitrate and ANC concentrations were created. Predicted surface-water nitrate concentrations were highest in small, high-elevation cirques, and concentrations declined downstream. Predicted ANC concentrations showed the opposite pattern, except in high-elevation areas underlain by metamorphic rocks along the Sierran Crest, which had relatively high predicted ANC (>200 μeq L-1). Maps were created to show where basin characteristics predispose aquatic resources to nutrient enrichment and acidification effects from N and S deposition. The maps can be used to help guide development of

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Sources of sulfate supporting anaerobic metabolism in a contaminated aquifer

    Science.gov (United States)

    Ulrich, G.A.; Breit, G.N.; Cozzarelli, I.M.; Suflita, J.M.

    2003-01-01

    Field and laboratory techniques were used to identify the biogeochemical factors affecting sulfate reduction in a shallow, unconsolidated alluvial aquifer contaminated with landfill leachate. Depth profiles of 35S-sulfate reduction rates in aquifer sediments were positively correlated with the concentration of dissolved sulfate. Manipulation of the sulfate concentration in samples revealed a Michaelis-Menten-like relationship with an apparent Km and Vmax of approximately 80 and 0.83 ??M SO4-2??day-1, respectively. The concentration of sulfate in the core of the leachate plume was well below 20 ??M and coincided with very low reduction rates. Thus, the concentration and availability of this anion could limit in situ sulfate-reducing activity. Three sulfate sources were identified, including iron sulfide oxidation, barite dissolution, and advective flux of sulfate. The relative importance of these sources varied with depth in the alluvium. The relatively high concentration of dissolved sulfate at the water table is attributed to the microbial oxidation of iron sulfides in response to fluctuations of the water table. At intermediate depths, barite dissolves in undersaturated pore water containing relatively high concentrations of dissolved barium (???100 ??M) and low concentrations of sulfate. Dissolution is consistent with the surface texture of detrital barite grains in contact with leachate. Laboratory incubations of unamended and barite-amended aquifer slurries supported the field observation of increasing concentrations of barium in solution when sulfate reached low levels. At a deeper highly permeable interval just above the confining bottom layer of the aquifer, sulfate reduction rates were markedly higher than rates at intermediate depths. Sulfate is supplied to this deeper zone by advection of uncontaminated groundwater beneath the landfill. The measured rates of sulfate reduction in the aquifer also correlated with the abundance of accumulated iron sulfide

  18. 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.

  19. River-groundwater connectivity in a karst system, Wellington, New South Wales, Australia

    Science.gov (United States)

    Keshavarzi, Mohammadreza; Baker, Andy; Kelly, Bryce F. J.; Andersen, Martin S.

    2016-12-01

    The characterization of river-aquifer connectivity in karst environments is difficult due to the presence of conduits and caves. This work demonstrates how geophysical imaging combined with hydrogeological data can improve the conceptualization of surface-water and groundwater interactions in karst terrains. The objective of this study is to understand the association between the Bell River and karst-alluvial aquifer at Wellington, Australia. River and groundwater levels were continuously monitored, and electrical resistivity imaging and water quality surveys conducted. Two-dimensional resistivity imaging mapped the transition between the alluvium and karst. This is important for highlighting the proximity of the saturated alluvial sediments to the water-filled caves and conduits. In the unsaturated zone the resistivity imaging differentiated between air- and sediment-filled karst features, and in the saturated zone it mapped the location of possible water- and sediment-filled caves. Groundwater levels are dynamic and respond quickly to changes in the river stage, implying that there is a strong hydraulic connection, and that the river is losing and recharging the adjacent aquifer. Groundwater extractions (1,370 ML, megalitres, annually) from the alluvial aquifer can cause the groundwater level to fall by as much as 1.5 m in a year. However, when the Bell River flows after significant rainfall in the upper catchment, river-leakage rapidly recharges the alluvial and karst aquifers. This work demonstrates that in complex hydrogeological settings, the combined use of geophysical imaging, hydrograph analysis and geochemical measurements provide insights on the local karst hydrology and groundwater processes, which will enable better water-resource and karst management.

  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. A VS30 map for California with geologic and topographic constraints

    Science.gov (United States)

    Thompson, Eric; Wald, David J.; Worden, Charles

    2014-01-01

    For many earthquake engineering applications, site response is estimated through empirical correlations with the time‐averaged shear‐wave velocity to 30 m depth (VS30). These applications therefore depend on the availability of either site‐specific VS30 measurements or VS30 maps at local, regional, and global scales. Because VS30 measurements are sparse, a proxy frequently is needed to estimate VS30 at unsampled locations. We present a new VS30 map for California, which accounts for observational constraints from multiple sources and spatial scales, such as geology, topography, and site‐specific VS30measurements. We apply the geostatistical approach of regression kriging (RK) to combine these constraints for predicting VS30. For the VS30 trend, we start with geology‐based VS30 values and identify two distinct trends between topographic gradient and the residuals from the geology VS30 model. One trend applies to deep and fine Quaternary alluvium, whereas the second trend is slightly stronger and applies to Pleistocene sedimentary units. The RK framework ensures that the resulting map of California is locally refined to reflect the rapidly expanding database of VS30 measurements throughout California. We compare the accuracy of the new mapping method to a previously developed map of VS30 for California. We also illustrate the sensitivity of ground motions to the new VS30 map by comparing real and scenario ShakeMaps with VS30 values from our new map to those for existingVS30 maps.

  2. 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.

  3. Geological Investigation and analysis in response to Earthquake Induced Landslide in West Sumatra

    Science.gov (United States)

    Karnawati, D.; Wilopo, W.; Salahudin, S.; Sudarno, I.; Burton, P.

    2009-12-01

    Substantial socio-economical loss occurred in response to the September 30. 2009 West Sumatra Earthquake with magnitude of 7.6. Damage of houses and engineered structures mostly occurred at the low land of alluvium sediments due to the ground amplification, whilst at the high land of mountain slopes several villages were buried by massive debris of rocks and soils. It was recorded that 1115 people died due to this disasters. Series of geological investigation was carried out by Geological Engineering Department of Gadjah Mada University, with the purpose to support the rehabilitation program. Based on this preliminary investigation it was identified that most of the house and engineered structural damages at the alluvial deposits mainly due to by the poor quality of such houses and engineered structures, which poorly resist the ground amplification, instead of due to the control of geological conditions. On the other hand, the existence and distribution of structural geology (faults and joints) at the mountaineous regions are significant in controlling the distribution of landslides, with the types of rock falls, debris flows and debris falls. Despite the landslide susceptibility mapping conducted by Geological Survey of Indonesia, more detailed investigation is required to be carried out in the region surrounding Maninjau Lake, in order to provide safer places for village relocation. Accordingly Gadjah Mada University in collaboration with the local university (Andalas University) as well as with the local Government of Agam Regency and the Geological Survey of Indonesia, serve the mission for conducting rather more detailed geological and landslide investigation. It is also crucial that the investigation (survey and mapping) on the social perception and expectation of local people living in this landslide susceptible area should also be carried out, to support the mitigation effort of any future potential earthquake induced landslides.

  4. Numerical modelling of groundwater flow to understand the impacts of pumping on arsenic migration in the aquifer of North Bengal Plain

    Indian Academy of Sciences (India)

    P K Sikdar; Surajit Chakraborty

    2017-03-01

    In this paper, numerical simulations of regional-scale groundwater flow of North Bengal Plain have been carried out with special emphasis on the arsenic (As)-rich alluvium filled gap between the Rajmahal hills on the west and the Garo hills on the east. The proposed concern of this modelling arose from development that has led to large water table declines in the urban area of English Bazar block, Malda district, West Bengal and possible transport of As in the near future from the adjacent As-polluted aquifer. Groundwater occurs under unconfined condition in a thick zone of saturation within the Quaternaryalluvial sediments. Modelling indicates that current pumping has significantly changed the groundwater flowpaths from pre-development condition. At the present pumping rate, the pumping wells of the urban area may remain uncontaminated till the next 25 yrs, considering only pure advection of water but some water from the As-polluted zone may enter wells by 50 yrs. But geochemical and other processes such as adsorption, precipitation, redox reaction and microbial activity may significantly retard the predicted rate by advective transport. In the rural areas, majority of the water pumped from the aquifer is forirrigation, which is continuously re-applied on the surface. The near-vertical nature of the flowpaths indicates that, where As is present or released at shallow depths, it will continue to occur in pumping wells. Modelling also indicates that placing all the pumping wells at depths below 100 m may not provideAs-free water permanently.

  5. Applying a Model of Curvature-Driven Bend Migration Developed for Alluvial Rivers to a Gravel-Bedded River With Reaches of Exposed Bedrock

    Science.gov (United States)

    Narinesingh, P.; Pizzuto, J. E.

    2009-12-01

    The South River, Virginia, a sinuous, gravel-bedded river influenced by frequent bedrock exposures, appears at first glance to be meandering. However, when its planform statistics are compared to a freely meandering river (the Teklanika River, Alaska), systematic differences become apparent. Bends of the South River have shorter lengths, longer radii of curvatures, a distinctive meander wavelength spectrum, and a lower fractal dimension of D = 1.11 than those of the Teklanika River. Sixty five percent of the length of South River in the study area consists of sections with exposed bedrock (either on the bed or the banks) and islands. Alluvial floodplains of varying lengths are scattered between sections of bedrock and islands, accounting for the remaining 35% of the study reach. In these areas, the South River displays sinuosity values that may be as high as 2.5. Within the alluvial reaches, aerial photographs from 1937 and 2005 document significant channel migration. Driven by the need to quantify the flux of mercury-contaminated sediments entering the river through bank erosion, we applied the bend migration model of Johannesson and Parker (1989). The model, when schematized for hydraulics of the alluvial sections of the South River and calibrated to the total area of erosion mapped from aerial photographs, correctly predicts 45% of the observed locations of erosion as mapped from the aerial photographs and observed in the field. The total area of erosion computed using the predicted near-bank excess velocity is within 14% of that mapped. According to a non-parametric Kruskal-Wallis test, the predicted areas of erosion along the river are not significantly different from those defined by the historical aerial photographs (P >= 0.05, two tailed test). These results suggest that curvature dependent hydraulic models for alluvial rivers may provide useful predictions of total erosion of alluvium on mixed bedrock/alluvial rivers like the South River. However, improved

  6. River-groundwater connectivity in a karst system, Wellington, New South Wales, Australia

    Science.gov (United States)

    Keshavarzi, Mohammadreza; Baker, Andy; Kelly, Bryce F. J.; Andersen, Martin S.

    2017-03-01

    The characterization of river-aquifer connectivity in karst environments is difficult due to the presence of conduits and caves. This work demonstrates how geophysical imaging combined with hydrogeological data can improve the conceptualization of surface-water and groundwater interactions in karst terrains. The objective of this study is to understand the association between the Bell River and karst-alluvial aquifer at Wellington, Australia. River and groundwater levels were continuously monitored, and electrical resistivity imaging and water quality surveys conducted. Two-dimensional resistivity imaging mapped the transition between the alluvium and karst. This is important for highlighting the proximity of the saturated alluvial sediments to the water-filled caves and conduits. In the unsaturated zone the resistivity imaging differentiated between air- and sediment-filled karst features, and in the saturated zone it mapped the location of possible water- and sediment-filled caves. Groundwater levels are dynamic and respond quickly to changes in the river stage, implying that there is a strong hydraulic connection, and that the river is losing and recharging the adjacent aquifer. Groundwater extractions (1,370 ML, megalitres, annually) from the alluvial aquifer can cause the groundwater level to fall by as much as 1.5 m in a year. However, when the Bell River flows after significant rainfall in the upper catchment, river-leakage rapidly recharges the alluvial and karst aquifers. This work demonstrates that in complex hydrogeological settings, the combined use of geophysical imaging, hydrograph analysis and geochemical measurements provide insights on the local karst hydrology and groundwater processes, which will enable better water-resource and karst management.

  7. Shallow electrical resistivity imaging of the Limón fault, Chagres River Watershed, Panama Canal

    Science.gov (United States)

    Mojica, Alexis; Pérez, Tatiana; Toral, Jaime; Miranda, Roberto; Franceschi, Pastora; Calderón, Carlos; Vergara, Fidedigna

    2017-03-01

    The aim of this study was the use of electrical resistivity imaging to investigate the geometry of the southwest portion of one of the most important geologic fault zones of the Panama Canal Watershed: the Limón fault. This fault is characterized by its juxtaposition of pre-Tertiary andesitic basalt (Playa Venado Formation) against late Oligocene Tertiary sediments (Caimito Formation). In this zone, four 2D electrical resistivity tomography profiles were conducted perpendicular to the fault trace: T-1, T-2, T-3 and T-4. The T-1, T-3, and T-4 profiles were long profiles (235 m for the first two and 215 m for the last one), with a goal of determining the depth of the geologic boundary between the sedimentary and andesitic deposits. The T-2 profile was a short profile (23.5 m), with the objective of calibrating the results with data provided by the paleoseismic trenching previously developed in the area of interest. For these tests, two electrode arrays of types Wenner-Schlumberger and Dipole-Dipole, were used. For the inversion routine, two regularized least-squares methods were used: the smoothness-constrained method and robust inversion. The long electrical resistivity tomography profiles were able to identify a set of electrical anomalies associated with the andesitic basalt and the Tertiary sediments and with that, the contact geometry between these formations. In these profiles, fault angle measurements ranged from 60° to 80° with respect to the ground surface. In the T-2 profile, the electrical anomalies showed a good association with the results of the paleoseismic study. This allowed identification of the colluvium and alluvium covering the gravel and sand debris that mark the gradual transition to the soils of the Caimito Formation. Finally, a set of 2D synthetic models was developed for each of the T-1, T-3, and T-4 profiles with the objective of optimizing interpretation of the field results.

  8. The 8th June 2008 Mw=6.4 earthquake in NW Peloponnesus: preliminary results from seismic, GPS and field data

    Science.gov (United States)

    Ganas, A.; Serpelloni, E.; Kolligri, M.; Drakatos, G.; Adamis, I.; Tsimi, C.; Batsi, E.; Papanikolaou, M.; Petrou, P.; Argyrakis, P.

    2009-04-01

    On June 8, 2008 at 12:25 UTC a strong earthquake occurred (M=6.4) in NW Peloponnesus, western Greece. The focal mechanism was determined as strike-slip by several institutions operating in central and eastern Mediterranean. This event is the largest strike-slip earthquake to occur in western Greece during the past 25 years. The hypocentre was located near the village Mihoi in Achaia prefecture (NW Peloponnesus), at a depth of about 18 km. A NOA team conducted field investigation one week after the event. There was no surface rupture. The geology of the area is mostly clastic sedimentary rocks and recent sediments (alluvium). Many rock falls, slides and liquefaction features have been found as is typical for an earthquake of this size. Double-difference relocations of 370 aftershocks show a linear pattern of events and define a clear NE-SW striking main shock fault plane. The aftershock region extends approximately 30 km in length, and the width of the surface projection of the aftershocks is mostly 5 km (max. 10 km). The depth of the aftershocks rarely exceeds 22 km. Analysis of high-rate GPS data from the permanent GPS network of NOA showed that station RLS (Riolos) which is located 12.8 km to the N5°W of the epicentre was displaced co-seismically 7 mm to the North in agreement with right-lateral kinematics of the rupture. Static (Coulomb) stress transfer analysis indicates loading of faults at mid-crustal levels near the towns of Patras (north) and Amaliada (south), respectively. The earthquake put more emphasis on the role of strike-slip faulting in the deformation of western Greece also indicating that seismic strain is partitioned between strike-slip and normal-slip events due to obliquity of the Nubia (Africa) subduction and the N-S extension of the overriding Aegean upper plate.

  9. 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.

  10. 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.

  11. USE OF SMALL-SCALE LIQUEFACTION FEATURES TO ASSESS PALEOSEISMICITY: AN EXAMPLE FROM THE SALINE RIVER FAULT ZONE, SOUTHEAST ARKANSAS, U.S.A.

    Directory of Open Access Journals (Sweden)

    Randel Tom Cox

    2014-11-01

    Full Text Available Large-scale liquefaction features (e.g., sand blows, lateral-spread fissure vents that can be recognized on remote-sensing imagery and photography have been of great utility in developing chronologies of paleo-earthquakes. In areas where large-scale features are obscured on imagery by forest cover and Holocene exposure is lacking, small-scale liquefaction features (e.g., convoluted bedding, clastic intrusions, foundered and suspended blocks, water-escape structures offer an alternative data source that can be investigated in meter-scale excavations. In order to assess the geographic extent of Holocene sand blow fields in southeast Arkansas that were previously mapped on river terraces and flood plains using aerial photography, we investigated the distribution of small-scale liquefaction features in alluvium along streams within a forested region between the sand blow fields. Our results suggest that the fields are not continuous and do not reflect a single large liquefaction field related to paleo-earthquakes >M 6.5. Features at one of our sites suggests the Desha County sand blow field may be larger than presently mapped, and that the distance from the center of the field to the farthest liquefaction may be ~30 km. The empirical relationship of magnitude and distance to farthest liquefaction suggests a field of this size could have been produced by a M 6.3 earthquake. We also found Holocene liquefaction features that we interpret as resulting from ground shaking near previously documented Pleistocene and Holocene surface ruptures of the Saline River fault zone. Liquefaction during a paleo-earthquake (~M 5.5 may have coincided with movement on that fault zone ~ AD 1700.

  12. 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.

  13. 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.

  14. Microseisms in geothermal exploration: studies in Grass Valley, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Liaw, A.L.C.

    1977-11-01

    Frequency-wavenumber (f-k) spectra of seismic noise in the bands 1 less than or equal to f less than or equal to 10 Hz in frequency and parallel bar k parallel bar less than or equal to 35.7 cycles/km in wavenumber, measured at several places in Grass Valley, Nevada, exhibit numerous features which can be correlated with variations in surface geology and sources associated with hot spring activity. Exploration techniques for geothermal reservoirs, based upon the spatial distribution of the amplitude and frequency characteristics of short-period seismic noise, are applied and evaluated in a field program at a potential geothermal area in Grass Valley, Nevada. A detailed investigation of the spatial and temporal characteristics of the noise field was made to guide subsequent data acquisition and processing. Contour maps of normalized noise-level derived from carefully sampled data are dominated by the hot spring noise source and the generally high noise levels outlining the regions of thick alluvium. Major faults are evident when they produce a shallow lateral contrast in rock properties. Conventional seismic noise mapping techniques cannot differentiate noise anomalies due to buried seismic sources from those due to shallow geological effects. The noise radiating from a deep reservoir ought to be evident as body waves of high phase velocity with time-invariant source azimuth. A small two-dimensional array was placed at 16 locations in the region to map propagation parameters. The f-k spectra reveal local shallow sources, but no evidence for a significant body wave component in the noise field was found. With proper data sampling, array processing provides a powerful method for mapping the horizontal component of the vector phase velocity of the noise field. In Grass Valley, and probably in most areas, the 2 to 10 Hz microseismic field is predominantly fundamental mode Rayleigh waves controlled by the very shallow structure.

  15. Digital data sets that describe aquifer characteristics of the Tillman terrace and alluvial aquifer in southwestern Oklahoma

    Science.gov (United States)

    Becker, C.J.; Runkle, D.L.; Rea, Alan

    1997-01-01

    ARC/INFO export and nonproprietary format files This diskette contains digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the Tillman terrace and alluvial aquifer in southwestern Oklahoma. The Tillman terrace aquifer encompasses the unconsolidated terrace deposits and alluvium associated with the North Fork of the Red River and the Red River in the western half of Tillman County. These sediments consist of discontinuous layers of clay, sandy clay, sand, and gravel. The aquifer extends over an area of 285 square miles and is used for irrigation and domestic purposes. Granite and the Hennessey Formation outcrop in northern parts of the aquifer where alluvial deposits are absent. These outcrops were included as part of the aquifer in a thesis that modeled the ground-water flow in the aquifer. Most of the aquifer boundaries and some of the lines in the hydraulic conductivity and recharge data sets were extracted from a published digital surficial geology data set based on a scale of 1:250,000. Most of the lines in the hydraulic conductivity, recharge, and 1969 water-level elevation contour data sets, and one line in the aquifer boundary data set were digitized from a paper map published at a scale of 1:249,695 in a thesis in which the ground-water flow in the aquifer was modeled. Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. Therefore, values of hydraulic conductivity and recharge used in the model and presented in this data set are not precise, but are within a reasonable range when compared to independently collected data.

  16. Investigation of Usability as Industrial Raw Material of Olivine Occurrences: A Case Study from Gelendost - Isparta, Southwestern Turkey

    Science.gov (United States)

    Cengiz, Oya; Kurşunluoğlu, Mustafa

    2016-10-01

    Olivine occurrences are located in the northwest of Madenli and Eğirler villages in Gelendost-Isparta, Southwestern Turkey. The aim of this study is to investigate usability as an industrial raw material of olivine formations in the peridotite. For this purpose, geological, mineralogical and geochemical properties of olivine-rich rocks outcropping in the field were examined. Allochthonous units belonging to Beyşehir-Hoyran Nappes are formed in the Upper Eocene settlement aged Şarkikaraağaç Ophiolites, the Upper Cretaceous Eğirler Formation that contains wild flysch, and the Upper Triassic Deliktaş Formation that consists of recrystallized massive limestone. The Anamas-Akseki Autochthonous units are the Jurassic-Cretaceous Hacıalabaz formation, which consists of dolomite and limestone, the Neogene deposits and the Quaternary alluvium. Harzburgite and dunite are observed in peridotite at the bottom of Şarkikaraağaç Ophiolite. They are dominant rocks of olivine occurrences in the field and include mainly olivine, enstatite, stockwork and vein magnesite, and locally chromite. The concentrations of major oxides for harzburgite samples vary between 41.98 and 44.59% SiO2, between 41.32 to 45.74% MgO, and between 8.75 and 9.82% Fe2O3. The samples ranged from 0.1-4.50% loss on ignition of significance for their usability. Major oxide contents and loss on ignition values of olivine-rich harzburgite samples in the study area partly comply with the standard values that have been determined to be suitable for usage in industry. Consequently, olivine occurrences in the study area are used as olivine sand in industry.

  17. 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.

  18. Hydrogeochemical parameters for assessment of groundwater quality in the upper Gunjanaeru River basin, Cuddapah District, Andhra Pradesh, South India

    Science.gov (United States)

    Raju, N. Janardhana

    2007-06-01

    In the management of water resources, quality of water is just as important as its quantity. In order to know the quality and/or suitability of groundwater for domestic and irrigation in upper Gunjanaeru River basin, 51 water samples in post-monsoon and 46 in pre-monsoon seasons were collected and analyzed for various parameters. Geological units are alluvium, shale and quartzite. Based on the analytical results, chemical indices like percent sodium, sodium adsorption ratio, residual sodium carbonate, permeability index (PI) and chloroalkaline indices were calculated. The pre-monsoon waters have low sodium hazard as compared to post-monsoon season. Residual sodium carbonate values revealed that one sample is not suitable in both the seasons for irrigation purposes due the occurrence of alkaline white patches and low permeability of the soil. PI values of both seasons revealed that the ground waters are generally suitable for irrigation. The positive values of Chloroalkaline indices in post-monsoon (80%) and in pre-monsoon (59%) water samples indicate absence of base-exchange reaction (chloroalkaline disequilibrium), and remaining samples of negative values of the ratios indicate base-exchange reaction (chloroalkaline equilibrium). Chadha rectangular diagram for geochemical classification and hydrochemical processes of groundwater for both seasons indicates that most of waters are Ca Mg HCO3 type. Assessment of water samples from various methods indicated that majority of the water samples in both seasons are suitable for different purposes except at Yanadipalle (sample no. 8) that requires precautionary measures. The overall quality of groundwater in post-monsoon season in all chemical constituents is on the higher side due to dissolution of surface pollutants during the infiltration and percolation of rainwater and at few places due to agricultural and domestic activities.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  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. 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.

  6. An efficient surrogate-based simulation-optimization method for calibrating a regional MODFLOW model

    Science.gov (United States)

    Chen, Mingjie; Izady, Azizallah; Abdalla, Osman A.

    2017-01-01

    Simulation-optimization method entails a large number of model simulations, which is computationally intensive or even prohibitive if the model simulation is extremely time-consuming. Statistical models have been examined as a surrogate of the high-fidelity physical model during simulation-optimization process to tackle this problem. Among them, Multivariate Adaptive Regression Splines (MARS), a non-parametric adaptive regression method, is superior in overcoming problems of high-dimensions and discontinuities of the data. Furthermore, the stability and accuracy of MARS model can be improved by bootstrap aggregating methods, namely, bagging. In this paper, Bagging MARS (BMARS) method is integrated to a surrogate-based simulation-optimization framework to calibrate a three-dimensional MODFLOW model, which is developed to simulate the groundwater flow in an arid hardrock-alluvium region in northwestern Oman. The physical MODFLOW model is surrogated by the statistical model developed using BMARS algorithm. The surrogate model, which is fitted and validated using training dataset generated by the physical model, can approximate solutions rapidly. An efficient Sobol' method is employed to calculate global sensitivities of head outputs to input parameters, which are used to analyze their importance for the model outputs spatiotemporally. Only sensitive parameters are included in the calibration process to further improve the computational efficiency. Normalized root mean square error (NRMSE) between measured and simulated heads at observation wells is used as the objective function to be minimized during optimization. The reasonable history match between the simulated and observed heads demonstrated feasibility of this high-efficient calibration framework.

  7. Effect of coal ash disposal upon an unconfined alluvial system

    Energy Technology Data Exchange (ETDEWEB)

    Shergill, B.S.; Sendlein, L.V.A. (Univ. of Kentucky, Lexington, KY (United States). Dept. of Geological Sciences); Dinger, J.S. (Univ. of Kentucky, Lexington, KY (United States). Kentucky Geological Survey)

    1992-01-01

    Fly and bottom ash from coal combustion has been disposed in four ash ponds in an alluvial valley. Three of the ash ponds are receiving ash and one was filled and closed. Twenty eight monitoring wells ranging in depth from 10 feet to 65 feet have been installed at the site to study groundwater flow and chemistry. Hydraulic heads are influenced by the stage of the Kentucky River, and the flow direction is vertical below the ash ponds and predominantly horizontal a short distance from the pond all the way to the river. Three different groundwater flow zones were observed and have unique water chemistry. The deep zone (near bedrock) has a low Eh (< [minus]80), and high concentration of Fe, ammonia nitrogen, below detection sulfate values (< 5 mg/l) and trace metals. The age of the deep groundwater as determined by tritium analyses is between 20 to 30 years old (5.68 TU). The intermediate groundwater zone (from ash pond) has relatively higher Eh (> 100) and lower concentrations of Fe and ammonia nitrogen, median sulfate concentration (114 mg/l), and arsenic is below detection limits. The shallow groundwater zone is through the closed out ash point and has higher concentrations of nearly all cations and anions, including sulfate (888 mg/l) and arsenic (exists as arsenite) at concentration of 0.9 mg/l, low Eh (< [minus]100), and high pH. When shallow flow enters the alluvium, the sulfate are attenuated by sulfate reduction and this results in high bicarbonate values. Saturation indices (SI) as calculated by the geochemical model, MINTEQA2, indicate that deep and intermediate groundwater are unsaturated and shallow groundwater is at or near equilibrium with respect to calcite, dolomite, and gypsum.

  8. Subsurface structure of the East Bay Plain ground-water basin: San Francisco Bay to the Hayward fault, Alameda County, California

    Science.gov (United States)

    Catchings, R.D.; Borchers, J.W.; Goldman, M.R.; Gandhok, G.; Ponce, D.A.; Steedman, C.E.

    2006-01-01

    The area of California between the San Francisco Bay, San Pablo Bay, Santa Clara Valley, and the Diablo Ranges (East Bay Hills), commonly referred to as the 'East Bay', contains the East Bay Plain and Niles Cone ground-water basins. The area has a population of 1.46 million (2003 US Census), largely distributed among several cities, including Alameda, Berkeley, Fremont, Hayward, Newark, Oakland, San Leandro, San Lorenzo, and Union City. Major known tectonic structures in the East Bay area include the Hayward Fault and the Diablo Range to the east and a relatively deep sedimentary basin known as the San Leandro Basin beneath the eastern part of the bay. Known active faults, such as the Hayward, Calaveras, and San Andreas pose significant earthquake hazards to the region, and these and related faults also affect ground-water flow in the San Francisco Bay area. Because most of the valley comprising the San Francisco Bay area is covered by Holocene alluvium or water at the surface, our knowledge of the existence and locations of such faults, their potential hazards, and their effects on ground-water flow within the alluvial basins is incomplete. To better understand the subsurface stratigraphy and structures and their effects on ground-water and earthquake hazards, the U.S. Geological Survey (USGS), in cooperation with the East Bay Municipal Utility District (EBMUD), acquired a series of high-resolution seismic reflection and refraction profiles across the East Bay Plain near San Leandro in June 2002. In this report, we present results of the seismic imaging investigations, with emphasis on ground water.

  9. 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.

  10. 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).

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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, Jeffrey S.; McGeehin, John P.

    2016-09-01

    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, followed by

  18. Extreme river response to climate-induced aggradation in a forested, montane basin, Carbon River, Mount Rainier National Park, Washington, United States

    Science.gov (United States)

    Beyeler, J. D.; Rossi, R. K.; Kennard, P. M.; Beason, S. R.

    2013-12-01

    Climate change is drastically affecting the alpine landscape of Mount Rainier, encouraging glacial retreat, changes in snowpack thickness and longevity, and sediment delivery to downstream fluvial systems, leading to an extremely transport limited system and aggradation of the river valleys. River aggradation encourages devastating interactions between the pro-glacial braided fluvial systems and streamside floodplain ecosystems, in most places occupied by old-growth conifer forests. Current aggradation rates of the channels, bordered by late seral stage riparian forests, inhibit floodplain development, leading to an inverted relationship between perched river channels and lower-elevation adjacent floodplains. This disequilibrium creates a steeper gradient laterally towards the floodplains, rather than downstream; promoting flooding of streamside forest, removal and burial of vegetation with coarse alluvium, incision of avulsion channels, tree mortality, wood recruitment to channels, and ultimately widening the alluviated valley towards the glacially carved hillslopes. Aggradation and loss of streamside old-growth forest poses a significant problem to park infrastructure (e.g. roads, trails, and campgrounds) due to flood damage with as frequent as a two-year event. Other park rivers, the White River and Tahoma Creek, characterize two end-member cases. Despite an extremely perched channel, the White River is relatively stable; experiencing small avulsions while the old-growth streamside forest has remained mostly intact. These relatively small avulsions however severely impact park infrastructure, causing extensive flood damage and closure of the heavily trafficked state highway. Conversely debris flows on Tahoma Creek destroyed the streamside forest and migration across the valley is uninhibited. Mature streamside forests tend to oppose avulsions, sieving wood at the channel margins, promoting sediment deposition and deflection of erosive flows. Our study seeks to

  19. 基于BP算法的利用高含沙洪水淤地后土壤养分含量研究%RESEARCH ON CONTENT OF SOIL COMPONENT USING FLOOD WITH HIGH SAND AFTER SILTING ON BASE OF BP

    Institute of Scientific and Technical Information of China (English)

    于庆峰; 姬宝霖; 敖永贵

    2011-01-01

    利用线性回归、逐步多元回归两种方法建立的淤地后土壤养分含量与颗粒组成之间的数学模型,可以根据土壤颗粒组成快速估计土壤中各养分的含量,但误差比较大,在21.80%~11.38%之间.为了能进一步提高预测精度,利用人工智能技术建立淤地后土壤养分含量与颗粒组成之间的人工神经网络模型.结果表明,建立的BP、BPX、LMBP网络模型能够通过土壤颗粒快速预测土壤养分含量,且有很好精度,可以判定土壤养分丰缺程度,为施肥提出指导意见,从而促进利用高含沙洪水治沙淤地的应用发展.%Through leading the flood with high sand into the basin of the desert for silting up many times, when alluvium thickness exceed plow, the desert can becomes the high quantity farmland. It sample the 0 ~ 100cm section of wind - blown soil and new silt land and silted tilt in the flood irrigation area of Gongwusu, Erdos,Inner Mongolia, and menstruated the soil nutrient content and grain size constitute, in order to Analysis of the establishment of the artificial neural network model. The results show that BP,BPX,LMBP model to predict soil nutrient content, Forecast for up to a certain precision. Using this model can determine the soil nutrient rich and the lack of degree and provide guidance for fertilization. So as to promote the development of engineering application.

  20. 深埋黏土层冻结壁厚度的有限段高计算模型研究%Research on finite-length computational model of deep-buried frozen soil wall thickness

    Institute of Scientific and Technical Information of China (English)

    黄俐; 宋常军

    2016-01-01

    冻结壁设计理论关系到冻结法施工的成败,常规的弹塑性力学冻结壁厚度模型已不适用于深厚冲积层中冻结壁的设计。考虑卸载状态下冻结壁-周围未冻土的共同作用,基于三向应力状态下的冻土流变理论及偏张量虎克定律,建立了深埋黏土层有限段高冻结壁的变形及厚度计算模型。结合立井冻结工程,探讨了该计算模型对不同开挖因素的响应程度。结果表明:合理的降低段高、控制施工速度对冻结法凿井安全至关重要。该计算模型对深埋黏土层冻结壁设计有重要的理论意义。%As the design theory of frozen wall is the key of artificially ground freezing construction, and the conventional elastic-plastic mechanical models are not suitable for frozen wall design in deep alluvium. Considering the effect of excavation length and the interaction between frozen soil wall and its surrounding earth mass, the calculation models of deformation and thickness of finite-length frozen soil wall are developed based on the rheological theory of frozen soil and Hooke′s law of deviatoric tensor of equivalent stress-equivalent strain under tri-axial stress state. Combined with a shaft freezing engineering case, the influences of excavation length and duration of exposure on the calculation models are discussed. The results show that reducing the excavation section appropriately and controlling the construction speed reasonable is crucial to the safety of artificial freezing shaft sinking project.

  1. 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

  2. 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

  3. 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,Pro 4.1. The river aquifer interaction was simulated using the river boundary package.Hydraulic conductivity values were applied to specific zones and these ranged from 9.8 to 26.6 m/day.Recharge due to rainfall and irrigation returns were assigned to respective zones.Pumping rates of 500 m3/day, 1000 m3/day, 1500 m3/day, 2000 m3/day and 2500 m3/day were applied to appropriate areas of the model to simulate areas of stress.The zone budget shows a water balance de ficit for the period June 2006 to June 2007. The total recharge to the study area is 160.21 million m3 (Mcum). The groundwater draft through pumping is of the order of 233.56 Mcum, thus leaving a deficit balance of −73.35 Mcum. The sensitivity of the model to input parameters was tested by varying the parameters of interest over a range of values, monitoring the response of the model and determining the root mean square error of the simulated groundwater heads to the measured heads. These analyses showed that the model is most sensitive to hydraulic conductivity and

  4. Alluvial Morphology In Cohesive Sediment: The Mahakam Lowland Area

    Science.gov (United States)

    Vermeulen, B.; van Berkum, S.; Hoitink, A.; Sassi, M.; Hidayat, H.

    2011-12-01

    In the lower part of its course, the Mahakam River (Indonesia) flows through the subsiding Kutai Basin, through its own cohesive alluvium. The river is surrounded by a large number of floodplain lakes and peat domes. Its planform geometry and bed morphology reveal the presence of very sharp bends and associated deep scours. The lakes are connected to the river by small-sized tie-channels, which play a crucial role the discharge regime of the Mahakam downstream of the lake district. This study aims to establish the morphology of the sharp river bends and tie-channels, and to evaluate the contribution of sediment cohesion, riparian vegetation and the presence of peat in the area to river banks stability. Based on a detailed reconnaissance survey of the river banks, patterns of sedimentation and erosion in highly curved bends are found to be mirrored relative to those in mildly curved river stretches. Bars develop at the concave banks of sharp bends. On the convex sides, reattachment bars are often found, indicating flow separation at the inner bank. These sharp bends are thought to develop due to failure of the river to cutoff meanders due to erosion resistance of the banks. The top of the levees are located high in the landscape, forming a barrier between the surrounding swampy floodplains and the river. These levees form a buffer between the river corridor and peat domes, suggesting peat domes to be formed in areas outside the river corridor, rather than vice versa. Tie-channels are characterized by a very stable morphology and exhibit levees with decreasing height away from the river. The bed of these channels is armored with gravel and concretions of iron, organic matter and clay, suggesting that very high flow velocity can occur when the water level in the river changes abruptly. Both in the tie-channels and in the meandering part of the river, we found no apparent effect of vegetation on morphometric properties. We conclude the morphological characteristics of

  5. Cholistan and Cholistani Breed of Cattle

    Directory of Open Access Journals (Sweden)

    U. Farooq, H. A. Samad*, F. Sher1, M. Asim1 and M. Arif Khan2

    2010-04-01

    Full Text Available Cholistan, once a green and prosperous land with the source of water being the ancient Hakra River, was also the cradle of great Hakra Valley Civilization. It is sprawled at an area of 26,000 Km2, located between the latitudes 27º42´and 29º45´North and longitudes 69º52´and 75º24´East. The bioclimatic system of Cholistan falls under the category of “tropical desert” with very scanty rainfall. Geomorphologically, the soils of Cholistan are a complex blend of river alluvium and Aeolin sands. Based on topography, type of soil and vegetation, this desert is divided into two geomorphic regions: the Lesser Cholistan (the Northern 7,770 Km² region and the Greater Cholistan (the Southern 18,130 Km² region. The primary source of water is rainfall which is utilized through natural depressions or man-made ponds called “Tobas” and “Dahars.” The secondary source is underground water which is brackish and salty and not fit for human/animal consumption. Two livestock production systems prevail under pastoralism in Cholistan viz. transhumanie and nomadic. Despite an uncertain, unpredictable rainfall, low humidity and extremes in temperatures, Cholistan has long been famous for raising different breeds of livestock, contributing a significant share to national milk, meat and wool output. The total livestock population estimated during 2006 was 12,09528, out of which 47% were cattle. Cholistani cattle are considered to be ancestor of the Sahiwal and are a thermo-tolerant, tick-resistant breed. Preliminary data on some productive and reproductive traits of Cholistani cows maintained at Govt. Livestock Station, Jugait Peer, Bahawalpur during the period 2005 to 2009 revealed the avergae values for the productive traits i.e. lactation length, lactation yield, dry period, service period and fat percentage in milk as 165 days, 1235 liters, 155 days, 121 days and 4.8%, respectively. Similarly, the average values for reproductive traits i.e. age at

  6. Prospecting for natural attenuation: Coupled geophysical-biogeochemical studies at DOE's Rifle IFRC site

    Science.gov (United States)

    Williams, K. H.; Kukkadapu, R. K.; Long, P. E.; Flores Orozco, A.; Kemna, A.

    2011-12-01

    Research activities at the Rifle Integrated Field Research Challenge (IFRC) site in Rifle, Colorado (USA) are designed to integrate geochemical, biological, and hydrological studies to enhance our understanding of subsurface uranium mobility. While much of the research activities at the site have focused on stimulating subsurface microbial activity through acetate amendment, there is growing interest in the role that natural biogeochemical processes play in constraining uranium mobility in the aquifer. Such processes constitute a form of natural uranium attenuation in the subsurface and are inferred to result from elevated concentrations of natural organic matter associated with alluvial sediments. Referred to as naturally reduced zones (NRZ's), they are characterized by the presence of reduced and/or magnetic mineral phases (e.g. FeS, FeS2, and Fe3O4), elevated Fe(II), and refractory organic carbon compounds (e.g. roots, twigs, and cones). Elevated rates of microbial activity associated with NRZ's and their mineralogical makeup act to sequester uranium from groundwater at levels higher that background alluvium. Their unique composition within a matrix of relatively oxidized, low-bioactivity sediments constitutes a potential target for a variety of exploration geophysical techniques, such as induced polarization and magnetic susceptibility. Both methods have been successfully applied at the Rifle IFRC site to delineate the ubiquity and extent of NRZ's across the floodplain. Sediments recovered from drilling targets identified through the use of exploration geophysical techniques have identified elevated uranium concentrations associated with both magnetite and framboid pyrite; however, the extent to which such minerals are the direct product of in situ microbial activity remains unknown. While diverse, the microbial community composition of NRZ's suggest dominance by fermentative organisms capable of degrading lignitic carbon to low molecular weight organic

  7. Human Health Impact of Fluoride in Groundwater in the Chiang Mai Basin

    Science.gov (United States)

    Matsui, Y.; Takizawa, S.; Wattanachira, S.; Wongrueng, A.; Ibaraki, M.

    2005-12-01

    Chiang Mai Basin, in Northern Thailand, is known as a fluorotic area. Groundwater of the Chiang Mai Basin has been gradually replaced by contaminated surface water since the 1980's. People have been exposed to fluoride contaminated groundwater since that time. As a result, harmful health effects on dental and skeletal growth were observed in the 90's. These include dental and skeletal fluorosis. Dental fluorosis is characterized by yellow or white spots on teeth and pitting or mottled enamel, consequently causing the teeth to look unsightly. Skeletal fluorosis leads to changes in bone structure, making them extremely weak and brittle. The most severe form of this is known as ``crippling skeletal fluorosis,'' a condition that can cause immobility, muscle wasting, and neurological problems related to spinal cord compression. This study focuses on the problematic issue of the Chiang Mai Basin's groundwater from the viewpoint of fluoride occurrence and current health impacts. Chiang Mai and Lamphun Provinces comprise the Chiang Mai Basin. Fluoride rich granites or fluorite deposits are scattered across the mountainside of the Lamphun Province. Tropical savanna climate conditions with seasonal monsoons bring more than 1,000 mm of annual precipitation, which can prompt weathering of minerals containing fluoride. The Ping River dominates the Basin, and the main eastern tributary of the Ping River runs through the Lamphun Province. The Basin has geological units composed of lower semi-consolidated Tertiary fluvial and upper unconsolidated Quaternary alluvium deposits. The main aquifers are in the upper unconsolidated unit. High fluoride concentrations tend to be observed in the aquifer located in lower part of this unconsolidated unit. We have been investigating two areas in the Basin. These two locations are similar with respect to geological and hydrological settings. However, one area in which groundwater is Ca-bicarbonate dominant has a low fluoride occurrence

  8. Magnetotelluric study of the Pahute Mesa and Oasis Valley regions, Nye County, Nevada

    Science.gov (United States)

    Schenkel, Clifford J.; Hildenbrand, Thomas G.; Dixon, Gary L.

    1999-01-01

    Magnetotelluric data delineate distinct layers and lateral variations above the pre-Tertiary basement. On Pahute Mesa, three resistivity layers associated with the volcanic rocks are defined: a moderately resistive surface layer, an underlying conductive layer, and a deep resistive layer. Considerable geologic information can be derived from the conductive layer which extents from near the water table down to a depth of approximately 2 km. The increase in conductivity is probably related to zeolite zonation observed in the volcanic rock on Pahute Mesa, which is relatively impermeable to groundwater flow unless fractured. Inferred faults within this conductive layer are modeled on several profiles crossing the Thirsty Canyon fault zone. This fault zone extends from Pahute Mesa into Oasis Valley basin. Near Colson Pond where the basement is shallow, the Thirsty Canyon fault zone is several (~2.5) kilometers wide. Due to the indicated vertical offsets associated with the Thirsty Canyon fault zone, the fault zone may act as a barrier to transverse (E-W) groundwater flow by juxtaposing rocks of different permeabilities. We propose that the Thirsty Canyon fault zone diverts water southward from Pahute Mesa to Oasis Valley. The electrically conductive nature of this fault zone indicates the presence of abundant alteration minerals or a dense network of open and interconnected fractures filled with electrically conductive groundwater. The formation of alteration minerals require the presence of water suggesting that an extensive interconnected fracture system exists or existed at one time. Thus, the fractures within the fault zone may be either a barrier or a conduit for groundwater flow, depending on the degree of alteration and the volume of open pore space. In Oasis Valley basin, a conductive surface layer, composed of alluvium and possibly altered volcanic rocks, extends to a depth of 300 to 500 m. The underlying volcanic layer, composed mostly of tuffs, fills the

  9. Erosion, storage, and transport of sediment in two subbasins of the Rio Puerco, New Mexico

    Science.gov (United States)

    Gellis, A.C.; Pavich, M.J.; Ellwein, A.L.; Aby, S.; Clark, I.; Wieczorek, M.E.; Viger, R.

    2012-01-01

    Arroyos in the American Southwest proceed through cut-and-fill cycles that operate at centennial to millennial time scales. The geomorphic community has put much effort into understanding the causes of arroyo cutting in the late Quaternary and in the modern record (late 1800s), while little effort has gone into understanding how arroyos fill and the sources of this fill. Here, we successfully develop a geographic information system (GIS)-modeled sediment budget that is based on detailed field measurements of hillslope and channel erosion and deposition. Field measurements were made in two arroyo basins draining different lithologies and undergoing different land disturbance (Volcano Hill Wash, 9.30 km2; Arroyo Chavez, 2.11 km2) over a 3 yr period. Both basins have incised channels that formed in response to the late nineteenth-century incision of the Rio Puerco. Large volumes of sediment were generated during arroyo incision, equal to more than 100 yr of the current annual total sediment load (bed load + suspended load) in each basin. Downstream reaches in both arroyos are presently aggrading, and the main source of the sediment is from channel erosion in upstream reaches and first- and second-order tributaries. The sediment budget shows that channel erosion is the largest source of sediment in the current stage of the arroyo cycle: 98% and 80% of the sediment exported out of Volcano Hill Wash and Arroyo Chavez, respectively. The geomorphic surface most affected by arroyo incision and one of the most important sediment sources is the valley alluvium, where channel erosion, gullying, soil piping, and grazing all occur. Erosion rates calculated for the entire Volcano Hill Wash (-0.26 mm/yr) and Arroyo Chavez (-0.53 mm/yr) basins are higher than the modeled upland erosion rates in each basin, reflecting the large contributions from channel erosion. Erosion rates in each basin are affected by a combination of land disturbance (grazing) and lithology

  10. 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

  11. Pátek, Levousy a Chlumčany – významné fosiliferní středopleistocénní lokality na pravém břehu Ohře mezi Louny a Libochovicemi

    Directory of Open Access Journals (Sweden)

    Jiří Kovanda

    2005-05-01

    Full Text Available Due to a complete predominance of non-calcareous fluvial sediments in the Czech Republic, any find of fossil malacofauna is always considered as rare. The present work describes three localities in the Ohře river area, which contain, especially in the case of the Pátek locality, very abundant mid-Pleistocene malacofaunas. They were mainly collected in the floodplain fine-grained loam and back swamp deposits but also in sandy gravels. The molluscan thanatocenoses from localities near the Pátek village indicate the interglacial maximum (with up to 25 forest species s.l., which developed directly on a 30 m thick river terrace dating back to the period, during which the Ohře river established its present-day easterly course. The fossil molluscs from the Levousy locality come from floodplain loam deposits as well as from the underlying sandy terrace gravels. The species distribution, nevertheless, indicates only a transitional glacial-interglacial period. The somewhat higher morphologic position of the locality, as well as that of another section at Chlumčany, and complete predominance of local late Cretaceous material indicates that the Ohře river did not flow to the east yet during the accumulation of the floodplain deposits with molluscs, but still to the north, towards Bílina. The terrestrial malacofauna from the Chlumčany section came from floodplain marls, particularly from sandy tufa deposits in the alluvium, which contains no forest-biotope elements, but the presence of the species Columella columella – distinct representative of our „coldest“ loess deposits – is an absolute surprise, since the peak of production of the sandy tufa deposits has always been associated with climate optima of the interglacials and of the Holocene. Therefore, the described malacofaunas come from a boundary period, during which the Ohře river did not use its present-day valley (Levousy and Clumčany yet. Then, from the oldest time span, it took up

  12. Hydrology and water-quality monitoring considerations, Jackpile uranium mine, northwestern New Mexico

    Science.gov (United States)

    Zehner, H.H.

    1985-01-01

    The Jackpile Uranium Mine, which is on the Pueblo of Laguna in northwestern New Mexico, was operated from 1953 to 1980. The mine and facilities have affected 3,141 acres of land, and about 2,656 acres were yet to be reclaimed by late 1980. The intended use of the restored land is stock grazing. Fractured Dakota Sandstone and Mancos Shale of Cretaceous age overlie the Jackpile sandstone and a 200-ft-thick tight mudstone unit of the Brushy Basin Member underlies the Jackpile. The hydraulic conductivity of the Jackpile sandstone probably is about 0.3 ft/day. The small storage coefficients determined from three aquifer tests indicate that the Jackpile sandstone is a confined hydrologic system throughout much of the mine area. Sediment from the Rio Paguate has nearly filled the Paguate Reservoir near Laguna since its construction in 1940. The mean concentrations of uranium, Ra-226, and other trace elements generally were less than permissible limits established in national drinking water regulations or New Mexico State groundwater regulations. No individual surface water samples collected upstream from the mine contained concentrations of Ra-226 in excess of the permissible limits. Ra-226 concentrations in many individual samples collected from the Rio Paguate from near the mouth of the Rio Moquino to the sampling sites along the downstream reach of the Rio Paguate, however, exceeded the recommended permissible concentration of Ra-226 for public drinking water supplies. Concentrations in surface water apparently are changed by groundwater inflow near the confluence of the two streams. The altitude of the water tables in the backfill of the pits will be controlled partly by the water level in the Rio Paguate. Other factors controlling the altitudes of the water tables are the recharge rate to the backfill and the hydraulic conductivities of the backfill, alluvium, Jackpile sandstone, and mudstone unit of the Brushy Basin Member. After reclamation, most of the shallow

  13. A Study of the San Andreas Slip Rate on the San Francisco Peninsula, California

    Science.gov (United States)

    Feigelson, L. M.; Prentice, C.; Grove, K.; Caskey, J.; Ritz, J. F.; Leslie, S.

    2008-12-01

    The most recent large earthquake on the San Andreas Fault (SAF) along the San Francisco Peninsula was the great San Francisco earthquake of April 18, 1906, when a Mw= 7.8 event ruptured 435-470 km of the northern SAF. The slip rate for this segment of the SAF is incompletely known but is important for clarifying seismic hazard in this highly urbanized region. A previous study south of our site has found an average slip rate of 17±4 mm/yr for the late Holocene on the San Francisco Peninsula segment of the SAF. North of the Golden Gate, the SAF joins the San Gregorio Fault with an estimated slip rate of 6 mm/yr. A trench study north of where the two faults join has produced an average late Holocene slip rate of 24±3 mm/yr. To refine slip-rate estimates for the peninsula segment of the SAF, we excavated a trench across the fault where we located an abandoned channel between the San Andreas and Lower Crystal Springs reservoirs. This abandoned channel marks the time when a new channel cut across the SAF; the new channel has since been offset in a right-lateral sense about 20 m. The measured amount of offset and the age of the youngest fluvial sediments in the abandoned channel will yield a slip rate for the San Francisco Peninsula segment of the SAF. We excavated a trench across the abandoned channel and logged the exposed sediments. Our investigation revealed channel-fill alluvium incised and filled by probable debris flow sediments, and a wide fault zone in bedrock, west of the channel deposits. The most prominent fault is probably the strand that moved in 1906. We completed a total-station survey to more precisely measure the offset stream, and to confirm that the fault exposed in the trench aligns with a fence that is known to have been offset 2.8m during the 1906 earthquake. We interpret the debris flow sediments to represent the last phase of deposition prior to abandonment of the old channel. We collected samples for radiocarbon dating, optically stimulated

  14. 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.

  15. 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.

  16. 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

  17. Geologic map of the west half of the Blythe 30' by 60' quadrangle, Riverside County, California and La Paz County, Arizona

    Science.gov (United States)

    Stone, Paul

    2006-01-01

    deposits of the flanking alluvial fans and plains range in age from late Miocene to Holocene. Among the oldest of these deposits are limestone and fine-grained clastic sediments of the late Miocene and (or) Pliocene Bouse Formation, which is commonly interpreted to represent an estuary or marine embayment connected to the proto-Gulf of California. Most of the surficial deposits younger than the Bouse Formation are composed of alluvium either derived from local mountain ranges or transported into the area by the Colorado River. Large parts of the area, particularly near the northern margin, are covered by eolian sand, and small parts are covered by playa sediments.

  18. Geologic Map of the Kings Mountain and Grover Quadrangles, Cleveland and Gaston Counties, North Carolina, and Cherokee and York Counties, South Carolina

    Science.gov (United States)

    Horton, J. Wright

    2008-01-01

    sequence show a westward decrease from upper amphibolite facies (sillimanite zone) near the High Shoals Granite in the eastern side of the map area to upper greenschist (epidote-amphibolite) facies in the south-central part of the area near the Kings Mountain shear zone. Amphibolite-facies mineral assemblages in the Inner Piedmont terrane increase in grade from the kyanite zone near the Kings Mountain shear zone to the sillimanite zone in the northwestern part of the map area. Surficial deposits include alluvium in the stream valleys and colluvium along ridges and steep slopes. These quadrangles are unusual in the richness and variety of the mineral deposits that they contain, which include spodumene (lithium), cassiterite (tin), mica, feldspar, silica, clay, marble, kyanite and sillimanite, barite, manganese, sand and gravel, gold, pyrite, and iron.

  19. 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

  20. RESULTS OF THE PERFORMANCE ASSESSMENT FOR THE CLASSIFIED TRANSURANIC WASTES DISPOSED AT THE NEVADA TEST SITE

    Energy Technology Data Exchange (ETDEWEB)

    J. COCHRAN; ET AL

    2001-02-01

    Most transuranic (TRU) wastes are destined for the Waste Isolation Pilot Plant (WIPP). However, the TRU wastes from the cleanup of US nuclear weapons accidents are classified for national security reasons and cannot be disposed in WIPP. The US Department of Energy (DOE) sought an alternative disposal method for these ''special case'' TRU wastes and from 1984 to 1987, four Greater Confinement Disposal (GCD) boreholes were used to place these special case TRU wastes a minimum of 21 m (70 ft) below the land surface and a minimum of 200 m (650 ft) above the water table. The GCD boreholes are located in arid alluvium at the DOE's Nevada Test Site (NTS). Because of state regulatory concerns, the GCD boreholes have not been used for waste disposal since 1989. DOE requires that TRU waste disposal facilities meet the US Environmental Protection Agency's (EPA's) requirements for disposal of TRU wastes, which are contained in 40 CFR 191. This EPA standard sets a number of requirements, including probabilistic limits on the cumulative releases of radionuclides to the accessible environment for 10,000 years. The DOE Nevada Operations Office (DOE/NV) has contracted with Sandia National Laboratories (Sandia) to conduct a performance assessment (PA) to determine if the TRU waste emplaced in the GCD boreholes complies with the EPA's requirements. Sandia has completed the PA using all available information and an iterative PA methodology. This paper overviews the PA of the TRU wastes in the GCD boreholes [1]. As such, there are few cited references in this paper and the reader is referred to [1] and [2] for references. The results of the PA are that disposal of TRU wastes in the GCD boreholes easily complies with the EPA's 40 CFR 191 safety standards for disposal of TRU wastes. The PA is undergoing a DOE Headquarters (DOE/HQ) peer review, and the final PA will be released in FY2001 or FY2002.

  1. 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.

  2. Surface Deformation in Quetta Valley, Balochistan, Pakistan

    Science.gov (United States)

    Huang, J.; Shuhab, K.; Wulamu, A.; Crupa, W.; Khan, A. S.; Kakar, D. M.; Kasi, A.

    2015-12-01

    In February 2011, several ground fissures up to ~1.8 km in length appeared in the Quetta Valley, Balochsitan, Pakistan. It is not clear what caused the sudden occurrence of these fissures. The region is tectonically active and bounded to the west by several regional strike-slip faults including the north-south striking left-lateral Chaman fault system that slips at ~10 mm per year. Several large earthquakes have occurred recently in this area, one fatal 6.4 magnitude (Mw) earthquake occurred on October 28th, 2008. Some parts of Quetta Valley are subsiding; GPS data from two stations in Quetta that span mid-2006 - 2009 recorded subsidence rates of ~10 cm per year. Although subsidence in urban areas is generally attributed to groundwater depletion, it is not clear whether ground fissures are caused by water withdrawal or related to tectonics of the region. This study is designed to quantify and assess the source of surface deformation in Quetta Valley using InSAR, GPS, seismic and earthquake centroid moment tensor data. To detect and map the spatial-temporal features of the processes that led to the surface deformation, we used two time series, i.e., 15 European Remote Sensing (ERS-1/2) satellite images from 1992 - 1999 and 27 ENVISAT images spanning 2003 - 2010. A Differential Interferometric Synthetic Aperture Radar (DInSAR) Small Baseline Subset (SBAS) technique was used to investigate surface deformation. Eleven continuous-GPS stations within the InSAR antenna footprint were compared with the InSAR time series for quality control. Preliminary InSAR results revealed that the areas in and around the fissures are subsiding at 5 cm per year. Five seismic lines totaling ~60 km, acquired in 2003, were used to interpret faults beneath Holocene alluvium in the Quetta Valley. One of the blind faults is a north-south striking thrust fault mapped north into the Takatu range. However, a focal mechanism for the 2008 earthquake in this region indicated northwest

  3. Estimation of Vs30 Soil Profile Structure of Singapore from Microtremor Records

    Science.gov (United States)

    Walling, M. Y.; Megawati, K.; Zhu, C.

    2012-04-01

    Singapore lies at the southern tip of the Malay Peninsula, covering a land area of 600 km2 and with a population exceeding 5 million. Array microtremor recording were carried out in Singapore for 40 sites that encompasses the sites of all the major geological formations. The Spatial Autocorrelation (SPAC) method is employed to determine the phase velocity dispersion curves and subsequently inverted to determine the shallow shear-wave velocity (V s) and soil stratigraphy. The depth of penetration is generally about 30 m - 40 m for most of the sites. For the present study, the V s estimation is restricted to the upper 30 m of the soil (V s30), confirming with the IBC (2006). The Reclaimed Land and the young Quaternary soft soil deposit of Kallang Formation show low V s30 values ranging from 207 m/s - 247 m/s, belonging to site E and at the boundary of site E and D. The Old Alluvium formation shows higher V s30 values ranging from 362 m/s - 563 m/s and can be classified under site C. The estimated V s30 for the sedimentary sequence of Jurong Formation reveal site C classification, with the V s30 range from 317 m/s - 712 m/s. On the other hand, the Bukit Timah Granite body shows low V s30 ranging from 225 m/s - 387 m/s, with most of the sites concentrated under site D classification and few sites at the boundary of sites D and C, for the upper 30 m. This low V s30 value of the granitic body can be explained in the light of intense weathering that the granite body has undergone for the upper layer, which is also supported from borehole records. The SPAC results are compared with nearby borehole data and they show a good correlation for sites that have soft soil formation and for the weathered granite body. The correlation confirms the reliability of SPAC method that can be applied for highly populated urbanized places like Singapore. The present research finding will be useful for further studies of site response analysis, site characterization and ground motion

  4. An Integrated Approach on Groundwater Flow and Heat/Solute Transport for Sustainable Groundwater Source Heat Pump (GWHP) System Operation

    Science.gov (United States)

    Park, D. K.; Bae, G. O.; Joun, W.; Park, B. H.; Park, J.; Park, I.; Lee, K. K.

    2015-12-01

    The GWHP system uses a stable temperature of groundwater for cooling and heating in buildings and thus has been known as one of the most energy-saving and cost-efficient renewable energy techniques. A GWHP facility was installed at an island located at the confluence of North Han and South Han rivers, Korea. Because of well-developed alluvium, the aquifer is suitable for application of this system, extracting and injecting a large amount of groundwater. However, the numerical experiments under various operational conditions showed that it could be vulnerable to thermal interference due to the highly permeable gravel layer, as a preferential path of thermal plume migration, and limited space for well installation. Thus, regional groundwater flow must be an important factor of consideration for the efficient operation under these conditions but was found to be not simple in this site. While the groundwater level in this site totally depends on the river stage control of Paldang dam, the direction and velocity of the regional groundwater flow, observed using the colloidal borescope, have been changed hour by hour with the combined flows of both the rivers. During the pumping and injection tests, the water discharges in Cheongpyeong dam affected their respective results. Moreover, the measured NO3-N concentrations might imply the effect of agricultural activities around the facility on the groundwater quality along the regional flow. It is obvious that the extraction and injection of groundwater during the facility operation will affect the fate of the agricultural contaminants. Particularly, the gravel layer must also be a main path for contaminant migration. The simulations for contaminant transport during the facility operation showed that the operation strategy for only thermal efficiency could be unsafe and unstable in respect of groundwater quality. All these results concluded that the integrated approach on groundwater flow and heat/solute transport is necessary

  5. Potential impacts of damming the Juba Valley, western Somalia: Insights from geomorphology and alluvial history

    Science.gov (United States)

    Williams, Martin

    2014-05-01

    In 1988 plans were well advanced to dam the Juba River in western Somalia. The aims of the Baardheere Dam Project were to generate hydroelectric power for the capital Mogadishu, and to provide water for irrigation in the Juba Valley. A reconnaissance survey on foot along 500 km of the river upstream of the proposed dam site at Baardheere and detailed geomorphic mapping from air photos provided a basis for reconstructing the late Quaternary alluvial history of the river and for assessing the potential impact of the proposed dam. The Juba River rises in the Ethiopian Highlands and is the only river in Somalia that flows to the sea. Its history reflects climatic events in Ethiopia, where the Rift Valley lakes were very low during the LGM (21±2 ka), and high for about 5, 000 years before and after then. Cave deposits in Somalia indicate wetter conditions at 13, 10, 7.5 and 1.5 ka. Alluvial terraces in the Juba Valley range in age from late Pleistocene to late Holocene but only attain a few metres above the present floodplain. This is because the dry tributary valleys contain limestone caves and fissures that divert any high flows from the parent river underground, a process not known when the project was first approved. The oldest preserved terrace was cemented by calcrete by 40 ka. Alluvial gravels were deposited at the outlet of dry tributary valleys during times of episodic high-energy flow between 26 ka and 28 ka. Finely laminated shelly sands accumulated at 10 ka to form the 5 m terrace. The 2 m terrace was laid down 3.2 ka ago as a slackwater deposit. The lack of high-level alluvial terraces raises doubts over plans to dam the river, since rapid leakage would occur from side valleys and the reservoir would not attain the height needed to generate hydroelectric power. It would submerge all existing arable land along the river. Finally, the presence in the late Holocene alluvium of the sub-fossil gastropods Bulinus truncatus and Biomphalaria pfeifferi, which are

  6. Groundwater quality in the Santa Clara River Valley, California

    Science.gov (United States)

    Burton, Carmen A.; Landon, Matthew K.; Belitz, Kenneth

    2011-01-01

    The Santa Clara River Valley (SCRV) study unit is located in Los Angeles and Ventura Counties, California, and is bounded by the Santa Monica, San Gabriel, Topatopa, and Santa Ynez Mountains, and the Pacific Ocean. The 460-square-mile study unit includes eight groundwater basins: Ojai Valley, Upper Ojai Valley, Ventura River Valley, Santa Clara River Valley, Pleasant Valley, Arroyo Santa Rosa Valley, Las Posas Valley, and Simi Valley (California Department of Water Resources, 2003; Montrella and Belitz, 2009). The SCRV study unit has hot, dry summers and cool, moist winters. Average annual rainfall ranges from 12 to 28 inches. The study unit is drained by the Ventura and Santa Clara Rivers, and Calleguas Creek. The primary aquifer system in the Ventura River Valley, Ojai Valley, Upper Ojai Valley, and Simi Valley basins is largely unconfined alluvium. The primary aquifer system in the remaining groundwater basins mainly consists of unconfined sands and gravels in the upper portion and partially confined marine and nonmarine deposits in the lower portion. The primary aquifer system in the SCRV study unit is defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health (CDPH) database. Public-supply wells typically are completed in the primary aquifer system to depths of 200 to 1,100 feet below land surface (bls). The wells contain solid casing reaching from the land surface to a depth of about 60-700 feet, and are perforated below the solid casing to allow water into the well. Water quality in the primary aquifer system may differ from the water in the shallower and deeper parts of the aquifer. Land use in the study unit is approximately 40 percent (%) natural (primarily shrubs, grassland, and wetlands), 37% agricultural, and 23% urban. The primary crops are citrus, avocados, alfalfa, pasture, strawberries, and dry beans. The largest urban areas in the study unit are the cities of

  7. Late Quaternary Activity and Seismogenic Potential of the Gonave Microplate: Plantain Garden Strike-Slip Fault Zone of Eastern Jamaica

    Science.gov (United States)

    Mann, P.; Prentice, C.; King, W.; Demets, C.; Wiggins-Grandison, M.; Benford, B.

    2008-12-01

    At the longitude of Jamaica, Caribbean (Carib)-North America (Noam) plate motion of 19 ± 2 mm/a is carried by two parallel, left-lateral strike-slip faults, the Oriente fault zone, immediately south of Cuba, and the Enriquillo-Plantain Garden fault zone (EPGFZ), which lies 100-150 km further south. It has been postulated that the lithosphere between these faults constitutes an independent Gonave microplate that has formed in response to the ongoing collision between the leading edge of Carib in Hispaniola and the Bahama carbonate platform. GPS measurements in Jamaica and Hispanola is supportive of the microplate hypothesis and indicates that roughly half of Carib-Noam plate motion (8-14 mm/a) is carried by the EPGFZ of southern Hispaniola and eastern Jamaica. This study applies geomorphic and paleoseismic methods as a direct test of the activity and amount of microplate motion carried on the Plantain Garden fault segment of eastern Hispaniola and how this motion is distributed across a large restraining bend that has formed the island of Jamaica since the late Miocene. The EPFZ curves gently to the northeast and forming a steep mountain front to the Blue Mountains restraining bend with elevations up to 2200 m. Geomorphic fault-related features along the mountain front fault zone include left-laterally deflected rivers and streams, but no small scale features indicative of Holocene activity. River and stream deflections range from 0.1 to 0.5 km. We identified and trenched the most active trace of the mountain front fault at the Morant River where the fault is characterized by a 1.5-m-wide sub-vertical fault zone juxtaposing sheared alluvium and fault Cretaceous basement rocks This section is overlain by a 6-m-thick fluvial terrace. Trenching in the unfaulted terrace immediately overlying the fault trace revealed radiocarbon and OSL ages ranging from 20 to 21 ka that are consistent with a prominent unfaulted alluvial fan along the projection of this fault 1.5 km to

  8. 3D Geotechnical Soil Model of Nice, France, Inferred from Seismic Noise Measurements, for Seismic Hazard Assessment.

    Science.gov (United States)

    Bertrand, E.; Duval, A.; Castan, M.; Vidal, S.

    2007-12-01

    In seismic risk studies, the assessment of lithologic site effect is based on an accurate knowledge of mechanical properties and geometry of superficial geological formations. Therefore, we built a 3D subsurface model in the city of Nice, southeastern France, using not only geological and geotechnical data but also geophysical inputs. We used especially ambient vibration recordings to supply the lack of borehole data over the city. Nice spreads over 72 km2 and roughly 20% of the city is built upon recent alluvium deposits. Other parts of the city lie on Jurassic and Cretaceous rocks to the east and thick Pliocene conglomerates to the west. Nearly 450 boreholes located mainly in the alluvial valleys were used. Because they are essentially linked to previous planned constructions (such as road network or important building), their distribution is rather heterogeneous over the studied area. In the valleys moreover, less than 40% of the boreholes are reaching the rock basement. These boreholes have been analyzed and a representative soil column made of 9 sedimentary layers has been recognized. Shear wave velocity of these layers were obtained from Standard Penetration Test values using several empirical correlation law described in the literature. Because of its cost, an extended boring survey was not feasible to complete our data set. Traditional seismic profiling was also not intended, as it is not possible to use intensive explosive sources in town. Recent years have seen many studies using ambient vibration measurements for site effect estimation. Especially, the very simple H/V technique was proven to be suitable for microzoning studies although some limitation were pointed out when dealing with 2D or 3D structures. Nevertheless, this technique alone provides only the fundamental eigenfrequency of the site under investigation. But assuming the shear wave velocity in the sediment it can helps to constrain the depth of the bedrock thanks to the well known f0=VS/4H

  9. GT0 Explosion Sources for IMS Infrasound Calibration: Charge Design and Yield Estimation from Near-source Observations

    Science.gov (United States)

    Gitterman, Y.; Hofstetter, R.

    2014-03-01

    Three large-scale on-surface explosions were conducted by the Geophysical Institute of Israel (GII) at the Sayarim Military Range, Negev desert, Israel: about 82 tons of strong high explosives in August 2009, and two explosions of about 10 and 100 tons of ANFO explosives in January 2011. It was a collaborative effort between Israel, CTBTO, USA and several European countries, with the main goal to provide fully controlled ground truth (GT0) infrasound sources, monitored by extensive observations, for calibration of International Monitoring System (IMS) infrasound stations in Europe, Middle East and Asia. In all shots, the explosives were assembled like a pyramid/hemisphere on dry desert alluvium, with a complicated explosion design, different from the ideal homogenous hemisphere used in similar experiments in the past. Strong boosters and an upward charge detonation scheme were applied to provide more energy radiated to the atmosphere. Under these conditions the evaluation of the actual explosion yield, an important source parameter, is crucial for the GT0 calibration experiment. Audio-visual, air-shock and acoustic records were utilized for interpretation of observed unique blast effects, and for determination of blast wave parameters suited for yield estimation and the associated relationships. High-pressure gauges were deployed at 100-600 m to record air-blast properties, evaluate the efficiency of the charge design and energy generation, and provide a reliable estimation of the charge yield. The yield estimators, based on empirical scaled relations for well-known basic air-blast parameters—the peak pressure, impulse and positive phase duration, as well as on the crater dimensions and seismic magnitudes, were analyzed. A novel empirical scaled relationship for the little-known secondary shock delay was developed, consistent for broad ranges of ANFO charges and distances, which facilitates using this stable and reliable air-blast parameter as a new potential

  10. Geologic map of the Ute Mountain 7.5' quadrangle, Taos County, New Mexico, and Conejos and Costilla Counties, Colorado

    Science.gov (United States)

    Thompson, Ren A.; Turner, Kenzie J.; Shroba, Ralph R.; Cosca, Michael A.; Ruleman, Chester A.; Lee, John P.; Brandt, Theodore R.

    2014-01-01

    The Ute Mountain 7.5' quadrangle is located in the south-central part of the San Luis Basin of northern New Mexico, in the Rio Grande del Norte National Monument, and contains deposits that record volcanic, tectonic, and associated alluvial and colluvial processes over the past four million years. Ute Mountain has the distinction of being one of the largest intermediate composition eruptive centers of the Taos Plateau, a largely volcanic tableland occupying the southern portion of the San Luis Basin. Ute Mountain rises to an elevation in excess of 3,000 m, nearly 700 m above the basaltic plateau at its base, and is characterized by three distinct phases of Pliocene eruptive activity recorded in the stratigraphy exposed on the flanks of the mountain and in the Rio Grande gorge. Unconformably overlain by largely flat-lying lava flows of Servilleta Basalt, the area surrounding Ute Mountain records a westward thickening of basin-fill volcanic deposits interstratified in the subsurface with Pliocene basin-fill sedimentary deposits derived from older Tertiary and Precambrian sources to the east. Superimposed on this volcanic stratigraphy are alluvial and colluvial deposits derived from the flanks of Ute Mountain and more distally-derived alluvium from the uplifted Sangre de Cristo Mountains to the east, that record a complex temporal and stratigraphic succession of Quaternary basin deposition and erosion. Pliocene and younger basin deposition was accommodated along predominantly north-trending fault-bounded grabens. These poorly exposed fault scarps cutting lava flows of Ute Mountain volcano. The Servilleta Basalt and younger surficial deposits record largely down-to-east basinward displacement. Faults are identified with varying confidence levels in the map area. Recognizing and mapping faults developed near the surface in young, brittle volcanic rocks is difficult because: (1) they tend to form fractured zones tens of meters wide rather than discrete fault planes, (2

  11. Geology of the Western Part of Los Alamos National Laboratory (TA-3 to TA-16), Rio Grande Rift, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    C.J.Lewis; A.Lavine; S.L.Reneau; J.N.Gardner; R.Channell; C.W.Criswell

    2002-12-01

    We present data that elucidate the stratigraphy, geomorphology, and structure in the western part of Los Alamos National Laboratory between Technical Areas 3 and 16 (TA-3 and TA-16). Data include those gathered by geologic mapping of surficial, post-Bandelier Tuff strata, conventional and high-precision geologic mapping and geochemical analysis of cooling units within the Bandelier Tuff, logging of boreholes and a gas pipeline trench, and structural analysis using profiles, cross sections, structure contour maps, and stereographic projections. This work contributes to an improved understanding of the paleoseismic and geomorphic history of the area, which will aid in future seismic hazard evaluations and other investigations. The study area lies at the base of the main, 120-m (400-ft) high escarpment formed by the Pajarito fault, an active fault of the Rio Grande rift that bounds Los Alamos National Laboratory on the west. Subsidiary fracturing, faulting, and folding associated with the Pajarito fault zone extends at least 1,500 m (5,000 ft) to the east of the main Pajarito fault escarpment. Stratigraphic units in the study area include upper units of the Tshirege Member of the early Pleistocene Bandelier Tuff, early Pleistocene alluvial fan deposits that predate incision of canyons on this part of the Pajarito Plateau, and younger Pleistocene and Holocene alluvium and colluvium that postdate drainage incision. We discriminate four sets of structures in the area between TA-3 and TA-16: (a) north-striking faults and folds that mark the main zone of deformation, including a graben in the central part of the study area; (b) north-northwest-striking fractures and rare faults that bound the eastern side of the principal zone of deformation and may be the surface expression of deep-seated faulting; (c) rare northeast-striking structures near the northern limit of the area associated with the southern end of the Rendija Canyon fault; and (d) several small east

  12. Preliminary Geologic Map of the Sanchez Reservoir Quadrangle and Eastern Part of the Garcia Quadrangle, Costilla County, Colorado

    Science.gov (United States)

    Thompson, Ren A.; Machette, Michael N.; Drenth, Benjamin J.

    2007-01-01

    This geologic map is based entirely on new mapping by Thompson and Machette, whereas the geophysical data and interpretations were supplied by Drenth. The map area includes most of San Pedro Mesa, a basalt covered mesa that is uplifted as a horst between the Southern Sangre de Cristo fault zone (on the west) and the San Luis fault zone on the east. The map also includes most of the Sanchez graben, a deep structural basin that lies between the San Luis fault zone (on the west) and the Central Sangre de Cristo fault zone on the east. The oldest rocks in the map area are Proterozoic granites and Paleozoic sedimentary rocks, which are only exposed in a small hill on the west-central part of the mesa. The low hills that rise above San Pedro mesa are comprised of middle(?) Miocene volcanic rocks that are undated, but possibly correlative with mapped rocks to the east of Sanchez Reservoir. The bulk of the map area is comprised of the Servilleta Basalt, a regional series of flood basalts of Pliocene age. The west, north, and northeast margins of the mesa are covered by extensive landslide deposits that rest on poorly exposed sediment of the Santa Fe Group. Rare exposures of the sediment are comprised of siltstones, sandstones, and minor fluvial conglomerates. Most of the low ground surrounding the mesa is covered by surficial deposits of Quaternary age. The piedmont alluvium is subdivided into three Pleistocene units, and three Holocene units. The oldest Pleistocene gravel (unit Qao) forms an extensive coalesced alluvial fan and piedmont surface that is known as the Costilla Plains. This surface extends west from San Pedro Mesa to the Rio Grande. The primary geologic hazards in the map are are from earthquakes and landslides. There are three major fault zones in the area (as discussed above), and they all show evidence for late Pleistocene to possible Holocene movement. Two generations of landslides are mapped (younger and older), and both may have seismogenic origins.

  13. Geologic Map of the Clark Peak Quadrangle, Jackson and Larimer Counties, Colorado

    Science.gov (United States)

    Kellogg, Karl S.; Ruleman, Chester A.; Shroba, Ralph R.; Braddock, William A.

    2008-01-01

    deposits (mostly of Pinedale age), rock glaciers, block-slope deposits, landslide deposits, talus deposits, fan deposits, colluvium, and alluvium comprise the surficial deposits of the map area.

  14. 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

  15. Late Quaternary erosion events in lowland and mid-altitude Tasmania in relation to climate change and first human arrival

    Science.gov (United States)

    McIntosh, P. D.; Price, D. M.; Eberhard, R.; Slee, A. J.

    2009-05-01

    The establishment of a chronology of landscape-forming events in lowland and mid-altitude Tasmania, essential for assessing the relative importance of climatic and human influences on erosion, and for assessing present erosion risk, has been limited by the small number of ages obtained and limitations of dating methods. In this paper we critically assess previous Tasmanian studies, list published radiocarbon ages considered to be dependable, present new radiocarbon and thermoluminescence (TL) ages for 25 sites around Tasmania, and consider the evidence for the hypotheses that erosion processes at low and mid altitudes have been: (1) purely climatically controlled; and (2) influenced both by climatic and anthropogenic (increased fire frequency) effects. A total of 94 dependable finite ages (calibrated for radiocarbon and 'as measured' for TL and optically stimulated luminescence (OSL) determinations) are listed for deposits comprising dunes, colluvium, alluvium and loess-like aeolian deposits. Two fall in the >100 ka period, 15 fall in the period 65-35 ka, and 77 fall in the period 35-0.3 ka. There was a sustained increase in erosion recorded in the period 35-15 ka, as reflected by a greater number of dated aeolian deposits during this period. We considered three possible biases that may have affected the age distribution obtained: the limitations of radiocarbon dating, sampling bias, and preservation bias. Sampling bias may have favoured more recent dune strata, but radiocarbon dating and preservation biases are unlikely to have significantly distorted the age distribution obtained. Long but intermittent aeolian deposition is recorded at two sites (Southwood B; c. 59-28 ka and Dunlin Dune; c. 29-14 ka) but there is no evidence of regional loess deposits such as found in New Zealand. The timing of increased erosion in Tasmania between 35 and 30 ka approximately coincides with the intermittent ten-fold increase of dust accumulation between 33 and 30 ka in the

  16. 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

  17. Groundwater quality in the Monterey Bay and Salinas Valley groundwater basins, California

    Science.gov (United States)

    Kulongoski, Justin T.; Belitz, Kenneth

    2011-01-01

    The Monterey-Salinas study unit is nearly 1,000 square miles and consists of the Santa Cruz Purisima Formation Highlands, Felton Area, Scotts Valley, Soquel Valley, West Santa Cruz Terrace, Salinas Valley, Pajaro Valley, and Carmel Valley groundwater basins (California Department of Water Resources, 2003; Kulongski and Belitz, 2011). These basins were grouped into four study areas based primarily on geography. Groundwater basins in the north were grouped into the Santa Cruz study area, and those to the south were grouped into the Monterey Bay, the Salinas Valley, and the Paso Robles study areas (Kulongoski and others, 2007). The study unit has warm, dry summers and cool, moist winters. Average annual rainfall ranges from 31 inches in Santa Cruz in the north to 13 inches in Paso Robles in the south. The study areas are drained by several rivers and their principal tributaries: the Salinas, Pajaro, and Carmel Rivers, and San Lorenzo Creek. The Salinas Valley is a large intermontane valley that extends southeastward from Monterey Bay to Paso Robles. It has been filled, up to a thickness of 2,000 feet, with Tertiary and Quaternary marine and terrestrial sediments that overlie granitic basement. The Miocene-age Monterey Formation and Pliocene- to Pleistocene-age Paso Robles Formation, and Pleistocene to Holocene-age alluvium contain freshwater used for supply. The primary aquifers in the study unit are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells are typically drilled to depths of 200 to 650 feet, consist of solid casing from the land surface to depths of about 175 to 500 feet, and are perforated below the solid casing. Water quality in the primary aquifers may differ from that in the shallower and deeper parts of the aquifer system. Groundwater movement is generally from the southern part of the Salinas Valley north towards the Monterey Bay

  18. Water-Chemistry and On-Site Sulfur-Speciation Data for Selected Springs in Yellowstone National Park, Wyoming, 1996-1998

    Science.gov (United States)

    Ball, James W.; Nordstrom, Kirk D.; McCleskey, R. Blaine; Schoonen, Martin A.A.; Xu, Yong

    2001-01-01

    Fifty-eight water analyses are reported for samples collected from 19 hot springs and their overflow drainages and one ambient-temperature acid stream in Yellowstone National Park (YNP) during 1996-98. These water samples were collected and analyzed as part of research investigations on microbially mediated sulfur oxidation in stream waters and sulfur redox speciation in hot springs in YNP and chemical changes in overflow drainages that affect major ions, redox species, and trace elements. The research on sulfur redox speciation in hot springs is a collaboration with the State University of New York at Stony Brook, Northern Arizona University, and the U.S. Geological Survey (USGS). One ambient-temperature acidic stream system, Alluvium Creek and its tributaries in Brimstone Basin, was studied in detail. Analyses were performed adjacent to the sampling site, in an on-site mobile laboratory truck, or later in a USGS laboratory, depending on stability and preservability of the constituent. Water temperature, specific conductance, pH, Eh, dissolved oxygen (D.O.), and dissolved H2S were determined on-site at the time of sampling. Alkalinity and F were determined within a few days of sample collection by titration and by ion-selective electrode, respectively. Concentrations of S2O3 and SxO6 were determined as soon as possible (minutes to hours later) by ion chromatography (IC). Concentrations of Cl, SO4, and Br were determined by IC within a few days of sample collection. Concentrations of Fe(II) and Fe(total) were determined by ultraviolet/visible spectrophotometry within a few days of sample collection. Densities were determined later in the USGS laboratory. Concentrations of Li, Na, and K were determined by flame atomic absorption (Li) and emission (Na, K) spectrometry. Concentrations of Al, As(total), B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe(total), Mg, Mn, Ni, Pb, Si, Sr, V, and Zn were determined by inductively-coupled plasma optical emission spectrometry. Trace

  19. Geological and environmental implications of the evaporite karst in Spain

    Science.gov (United States)

    Gutiérrez, F.; Calaforra, J. M.; Cardona, F.; Ortí, F.; Durán, J. J.; Garay, P.

    2008-01-01

    galleries caused by the interception of a phreatic conduit. The main anthropogenic impacts on the endokarstic systems are related to the disposal of wastewaters and the destruction of caves by quarrying. The fluvial valleys that cross Tertiary evaporitic outcrops commonly show peculiar geological characteristics related to dissolution-induced synsedimentary subsidence phenomena: (1) Thickened alluvium filling dissolution basins up to several tens of kilometers long and more than 100 m deep. The largest thickenings are found in areas where the bedrock contains halite and glauberite. (2) Superimposed alluvial units locally bounded by angular unconformities. (3) Abundant deformational structures and paleosinkholes related to the rockhead and/or interstratal karstification of the substratum. These fluvial valleys typically are flanked by a prominent gypsum escarpment. Rock-falls favored by the dissolutional enlargement of joints derived from these scarps are the type of mass movement which has caused the highest number of casualties in Spain.

  20. Impact of halite dissolution subsidence on Quaternary fluvial terrace development: Case study of the Huerva River, Ebro Basin, NE Spain

    Science.gov (United States)

    Guerrero, Jesús; Gutiérrez, Francisco; Lucha, Pedro

    2008-08-01

    This paper analyses the control of evaporite dissolution subsidence on the evolution of the lower 30 km-long reach of the Huerva River up to its confluence with the Ebro River. In the study area the Huerva River flows across different interfingered lithofacies of the subhorizontally lying Ebro Basin fill: (1) shales and sandstones upstream of Cadrete; (2) evaporites dominated by gypsum between Cadrete and Cuarte; (3) gypsum with glauberite and halite units in the subsurface downstream of Cuarte. The halite shows a marked downvalley increase in thickness. Twelve terrace levels and seven pediment levels correlative to some of the terraces have been mapped in the studied area. Upstream of Cadrete, the terrace deposits, with a relatively constant thickness less than 4 m and overlying unsoluble bedrock, remain undeformed. Between Cadrete and Cuarte the deposits of some terraces show local thickening ( 60 m-thick terrace alluvium that fills a 5 km-long trough generated by synsedimentary subsidence phenomena caused primarily by the interstratal dissolution of halite. The older terraces (T1 to T4) show slight thickening (> 18 m) and locally truncate paleocollapse structures ascribed to the interstratal karstification of halite beds. The intermediate terraces (T5 to T7) correspond to degradation surfaces that grade downstream of Cuarte into aggradation flights underlain by the abruptly thickened deposits that fill this 5 km-long dissolution trough. Subsidence migrated episodically downstream during the generation of these terraces and the subsidence/aggradation rate was probably large enough to induce a base-level drop and knickpoint migration upstream generating strath terraces with convergent longitudinal profiles. The sedimentological changes that show the thickened terrace deposits in the subsidence area (high proportion of overbank fines (> 60%) including palustrine facies, gravel channels with lower width/depth ratio, multiple fining-upward cycles, decrease in the

  1. 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

  2. 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

  3. 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

  4. Effects of Subsetting by Parent Materials on Prediction of Soil Organic Matter Content in a Hilly Area Using Vis-NIR Spectroscopy.

    Science.gov (United States)

    Xu, Shengxiang; Shi, Xuezheng; Wang, Meiyan; Zhao, Yongcun

    2016-01-01

    Assessment and monitoring of soil organic matter (SOM) quality are important for understanding SOM dynamics and developing management practices that will enhance and maintain the productivity of agricultural soils. Visible and near-infrared (Vis-NIR) diffuse reflectance spectroscopy (350-2500 nm) has received increasing attention over the recent decades as a promising technique for SOM analysis. While heterogeneity of sample sets is one critical factor that complicates the prediction of soil properties from Vis-NIR spectra, a spectral library representing the local soil diversity needs to be constructed. The study area, covering a surface of 927 km2 and located in Yujiang County of Jiangsu Province, is characterized by a hilly area with different soil parent materials (e.g., red sandstone, shale, Quaternary red clay, and river alluvium). In total, 232 topsoil (0-20 cm) samples were collected for SOM analysis and scanned with a Vis-NIR spectrometer in the laboratory. Reflectance data were related to surface SOM content by means of a partial least square regression (PLSR) method and several data pre-processing techniques, such as first and second derivatives with a smoothing filter. The performance of the PLSR model was tested under different combinations of calibration/validation sets (global and local calibrations stratified according to parent materials). The results showed that the models based on the global calibrations can only make approximate predictions for SOM content (RMSE (root mean squared error) = 4.23-4.69 g kg-1; R2 (coefficient of determination) = 0.80-0.84; RPD (ratio of standard deviation to RMSE) = 2.19-2.44; RPIQ (ratio of performance to inter-quartile distance) = 2.88-3.08). Under the local calibrations, the individual PLSR models for each parent material improved SOM predictions (RMSE = 2.55-3.49 g kg-1; R2 = 0.87-0.93; RPD = 2.67-3.12; RPIQ = 3.15-4.02). Among the four different parent materials, the largest R2 and the smallest RMSE were

  5. Attenuation of River Contaminant using River Bank Infiltration in Jenderam Hilir, Dengkil, Selangor

    Directory of Open Access Journals (Sweden)

    Mohd Khairul Nizar Shamsuddin

    2013-11-01

    Full Text Available Bank infiltration (BI refers to the process of surface water seeping from the bank or bed of a river to the groundwater production wells. During the water’s passage through the ground, its quality changes due to microbial, chemical and physical processes, and due to mixing with groundwater in the aquifer. The BI study in Jenderam Hilir, Selangor is a pilot project to develop a better and sustainable source of water, and will provide a good platform to introduce this method in Malaysia. BI has been successfully implemented in many Asian and European countries. This site was chosen due to the high water demand in the area and groundwater is seen as one of the source with very high potential to be developed as supplementary source to meet the high public water supply demand. The objective of this study is to determine the effectiveness of BI and improving the quality of river water, and to determine the effective rate of water extraction from the alluvium in the study area. Twenty five (25 monitoring wells and 2 test wells were constructed at the study site and pumping tests have been carried on these two test wells. The pumping tests at the 2 test wells indicated that DW1 and DW2 were able to produce more than 15.9 m3/hr (0.3816 MLD and 128m3/hr (3.072 MLD respectively during the duration of 72 hours pumping tests with drawdown for DW1 was 4.17 m and DW2 was 2.63 m. The distance between the river and the test well is more than 18 m and the shortest travel time is 10 days. The river water was filtered through a 16 m thick silty sand for DW1 and 13 m thick gravelly sand for DW2. Both wells are located in confined aquifer adjacent to the Sungai Langat. Water quality analyses carried out for water from the Sungai Langat and groundwater from the wells showed decreased in turbidity, nitrate, aluminium and sulphate in groundwater which were very high in the Sungai Langat. Microorganism counting (E. coli, total coliform, Cryptosporidium and Giardia was

  6. 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

  7. Hydrogeologic Framework of the Upper Santa Cruz Basin (Arizona and Sonora) using Well Logs, Geologic Mapping, Gravity, Magnetics, and Electromagnetics

    Science.gov (United States)

    Callegary, J. B.; Page, W. R.; Megdal, S.; Gray, F.; Scott, C. A.; Berry, M.; Rangel, M.; Oroz Ramos, L.; Menges, C. M.; Jones, A.

    2011-12-01

    In 2006, the U.S. Congress passed the U.S.-Mexico Transboundary Aquifer Assessment Act which provides a framework for study of aquifers shared by the United States and Mexico. The aquifer of the Upper Santa Cruz Basin was chosen as one of four priority aquifers for several reasons, including water scarcity, a population greater than 300,000, groundwater as the sole source of water for human use, and a riparian corridor that is of regional significance for migratory birds and other animals. Several new mines are also being proposed for this area which may affect water quality and availability. To date, a number of studies have been carried out by a binational team composed of the U.S. Geological Survey, the Mexican National Water Commission, and the Universities of Arizona and Sonora. Construction of a cross-border hydrogeologic framework model of the basin between Amado, Arizona and its southern boundary in Sonora is currently a high priority. The relatively narrow Santa Cruz valley is a structural basin that did not experience the same degree of late Cenozoic lateral extension and consequent deepening as found in other basin-and-range alluvial basins, such as the Tucson basin, where basin depth exceeds 3000 meters. This implies that storage may be much less than that found in other basin-and-range aquifers. To investigate the geometry of the basin and facies changes within the alluvium, a database of over one thousand well logs has been developed, geologic mapping and transient electromagnetic (TEM) surveys have been carried out, and information from previous electromagnetic, magnetic, and gravity studies is being incorporated into the hydrogeologic framework. Initial geophysical surveys and analyses have focused on the portion of the basin west of Nogales, Arizona, because it supplies approximately 50% of that city's water. Previous gravity and magnetic modeling indicate that this area is a narrow, fault-controlled half graben. Preliminary modeling of airborne

  8. Tectonic geomorphology and paleoseismology of strike-slip faults in Jamaica: Implications for distribution of strain and seismic hazard along the southern edge of the Gonave microplate

    Science.gov (United States)

    Koehler, R. D.; Mann, P.; Brown, L. A.

    2009-12-01

    The east-west, left lateral strike-slip fault system forming the southern edge of the Gonave microplate crosses the110-km-long and 70-km-wide island of Jamaica. GPS measurements in the northeastern Caribbean are supportive of the microplate interpretation and indicate that ~ half of the Caribbean-North America left-lateral plate motion (8-14 mm/yr) is carried by the Plantain Garden (PGFZ) and associated faults in Jamaica. We performed Neotectonic mapping of the Plantain Garden fault along the southern rangefront of the Blue Mountains and conducted a paleoseismic study of the fault at Morant River. Between Holland Bay and Morant River, the fault is characterized by a steep, faceted, linear mountain front, prominent linear valleys and depressions, shutter ridges, and springs. At the eastern end of the island, the PGFZ is characterized by a left-stepping fault geometry that includes a major, active hot spring. The river cut exposure at Morant River exposes a 1.5-m-wide, sub-vertical fault zone juxtaposing sheared alluvium and faulted Cretaceous basement rocks. This section is overlain by an, unfaulted 3-m-thick fluvial terrace inset into a late Pleistocene terrace that is culturally modified. Upward fault terminations indicate the occurrence of three paleoearthquakes that occurred prior to deposition of the flat lying inset terrace around 341-628 cal yr BP. At this time, our radiocarbon results suggest that we can rule out the PGFZ as the source of the 1907 Kingston earthquake 102 years ago, as well as, the 1692 event that destroyed Port Royal 317 years ago and produced a major landslide at Yallahs. Pending OSL ages will constrain the age of the penultimate and most recent ruptures. Gently to steeply dipping rocks as young as Pliocene exposed in roadcuts within the low coastal hills south of and parallel to the Plantain Garden fault may indicate active folding and blind thrust faulting. These structures are poorly characterized and may accommodate an unknown amount of

  9. Multiple-Event Deformation on the West Tahoe Fault from Lidar and Trenching: Reconciling On and Offshore Paleoseismology

    Science.gov (United States)

    Seitz, G. G.; Mareschal, M.

    2014-12-01

    The West Tahoe Fault has a mapped length of 45 km, and its vertical slip rate is estimated at 0.6-1.0 mm/yr (Dingler et al., 2009). It is the range bounding, east dipping normal fault along the west margin of the basin, and the highest slip rate section is located along the western base of Lake Tahoe at a water depth of 400-500 m. In the lake, the fault has clearly defined scarps that displace submarine fans, lake-bottom sediments, and the ~50 ka age (Kent et al., 2005; Smith et al, 2013) McKinney Bay slide. Onshore the fault displaces tree-covered glacial and fluvial landforms. In October 2013 we conducted the first trenching study of the geomorphically well-defined West Tahoe Fault. Using Lidar, we selected a site with fine-grained surface sediments, as opposed to the boulder-rich moraine sediments that cover most of the onshore fault. The site is located ~3.5 km from the southern end of the mapped fault, adjacent to Osgood Swamp. In the excavation, we observed an east-dipping, normal fault juxtaposing glacial deposits against datable peat-bearing and charcoal-rich younger alluvial sediments. The glacial deposits and peat layers can be matched across the fault. Clear evidence for two earthquakes was based on scarp-derived colluvium, fissures, faulted scarp-related alluvium, liquefaction, and upward terminations of faults. Retrodeformation of the sediments results in nearly equal vertical displacements of about 1.7 m/event. Results from multiple C-14 analysis place the most recent event at ~5.3 ka and the penultimate event at ~7.4 ka. The fault scarp at the trench is 3.5 m high; at the bottom of the lake at a depth of 400 m a postulated same-age fan as the trench site post-glacial deposits, has a vertical scarp of 10-12 m. As expected the slip rate decreases towards the southern end of the fault. However, if the same number of events resulted in the underwater scarp then events must average about 5-6 m vertical displacement per event. This has serious implications

  10. Chapter L: U.S. Industrial Garnet

    Science.gov (United States)

    Evans, James G.; Moyle, Phillip R.

    2006-01-01

    The United States presently consumes about 16 percent of global production of industrial garnet for use in abrasive airblasting, abrasive coatings, filtration media, waterjet cutting, and grinding. As of 2005, domestic garnet production has decreased from a high of 74,000 t in 1998, and imports have increased to the extent that as much as 60 percent of the garnet used in the United States in 2003 was imported, mainly from India, China, and Australia; Canada joined the list of suppliers in 2005. The principal type of garnet used is almandite (almandine), because of its specific gravity and hardness; andradite is also extensively used, although it is not as hard or dense as almandite. Most industrial-grade garnet is obtained from gneiss, amphibolite, schist, skarn, and igneous rocks and from alluvium derived from weathering and erosion of these rocks. Garnet mines and occurrences are located in 21 States, but the only presently active (2006) mines are in northern Idaho (garnet placers; one mine), southeastern Montana (garnet placers; one mine), and eastern New York (unweathered bedrock; two mines). In Idaho, garnet is mined from Tertiary and (or) Quaternary sedimentary deposits adjacent to garnetiferous metapelites that are correlated with the Wallace Formation of the Proterozoic Belt Supergroup. In New York, garnet is mined from crystalline rocks of the Adirondack Mountains that are part of the Proterozoic Grenville province, and from the southern Taconic Range that is part of the northern Appalachian Mountains. In Montana, sources of garnet in placers include amphibolite, mica schist, and gneiss of Archean age and younger granite. Two mines that were active in the recent past in southwestern Montana produced garnet from gold dredge tailings and saprolite. In this report, we review the history of garnet mining and production and describe some garnet occurrences in most of the Eastern States along the Appalachian Mountains and in some of the Western States where

  11. Field tracer investigation of unsaturated zone flow paths and mechanisms in agricultural soils of northwestern Mississippi, USA

    Science.gov (United States)

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

    2011-01-01

    In many farmed areas, intensive application of agricultural chemicals and withdrawal of groundwater for irrigation have led to water quality and supply issues. Unsaturated-zone processes, including preferential flow, play a major role in these effects but are not well understood. In the Bogue Phalia basin, an intensely agricultural area in the Delta region of northwestern Mississippi, the fine-textured soils often exhibit surface ponding and runoff after irrigation and rainfall as well as extensive surface cracking during prolonged dry periods. Fields are typically land-formed to promote surface flow into drainage ditches and streams that feed into larger river ecosystems. Downward flow of water below the root zone is considered minimal; regional groundwater models predict only 5% or less of precipitation recharges the heavily used alluvial aquifer. In this study transport mechanisms within and below the root zone of a fallow soybean field were assessed by performing a 2-m ring infiltration test with tracers and subsurface monitoring instruments. Seven months after tracer application, 48 continuous cores were collected for tracer extraction to define the extent of water movement and quantify preferential flow using a mass-balance approach. Vertical water movement was rapid below the pond indicating the importance of vertical preferential flow paths in the shallow unsaturated zone, especially to depths where agricultural disturbance occurs. Lateral flow of water at shallow depths was extensive and spatially non-uniform, reaching up to 10. m from the pond within 2. months. Within 1. month, the wetting front reached a textural boundary at 4-5. m between the fine-textured soil and sandy alluvium, now a potential capillary barrier which, prior to extensive irrigation withdrawals, was below the water table. Within 10. weeks, tracer was detectable at the water table which is presently about 12. m below land surface. Results indicate that 43% of percolation may be through

  12. Hydrogeology of the stratified-drift aquifers in the Cayuta Creek and Catatonk Creek valleys in parts of Tompkins, Schuyler, Chemung, and Tioga Counties, New York

    Science.gov (United States)

    Miller, Todd S.; Pitman, Lacey M.

    2012-01-01

    The surficial deposits, areal extent of aquifers, and the water-table configurations of the stratified-drift aquifer systems in the Cayuta Creek and Catatonk Creek valleys and their large tributary valleys in Tompkins, Schuyler, Chemung, and Tioga Counties, New York were mapped in 2009, in cooperation with the New York State Department of Environmental Conservation. Well and test-boring records, surficial deposit maps, Light Detection and Ranging (LIDAR) data, soils maps, and horizontal-to-vertical ambient-noise seismic surveys were used to map the extent of the aquifers, construct geologic sections, and determine the depth to bedrock (thickness of valley-fill deposits) at selected locations. Geologic materials in the study area include sedimentary bedrock, unstratified drift (till), stratified drift (glaciolacustrine and glaciofluvial deposits), and recent alluvium. Stratified drift consisting of glaciofluvial sand and gravel is the major component of the valley fill in this study area. The deposits are present in sufficient amounts in most places to form extensive unconfined aquifers throughout the study area and, in some places, confined aquifers. Stratified drift consisting of glaciolacustrine fine sand, silt, and clay are present locally in valleys underlying the surficial sand and gravel deposits in the southern part of the Catatonk Creek valley. These unconfined and confined aquifers are the source of water for most residents, farms, and businesses in the valleys. A generalized depiction of the water table in the unconfined aquifer was constructed using water-level measurements made from the 1950s through 2010, as well as LIDAR data that were used to determine the altitudes of perennial streams at 10-foot contour intervals and water surfaces of ponds and wetlands that are hydraulically connected to the unconfined aquifer. The configuration of the water-table contours indicate that the general direction of groundwater flow within Cayuta Creek and Catatonk

  13. Summary of Radionuclide Reactive Transport Experiments in Fractured Tuff and Carbonate Rocks from Yucca Flat, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Zavarin, M; Roberts, S; Reimus, P; Johnson, M

    2006-10-11

    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 inhibit radionuclide migration to the highly transmissive and regionally extensive lower carbonate aquifer (LCA) due to its wide-spread aerial extent, low permeability, and chemical reactivity. However, fast transport pathways through the TCU by way of fractures may provide a migration path for radionuclides to the LCA. Radionuclide transport in both TCU and the LCA fractures is likely to determine the location of the contaminant boundary for the Yucca Flat/Climax Mine Corrective Action Unit (CAU). Radionuclide transport through the TCU may involve both matrix and fracture flow. However, radionuclide migration over significant distances is likely to be dominated by fracture transport. Transport through the LCA will almost certainly be dominated by fracture flow, as the LCA has a very dense, low porosity matrix with very low permeability. Because of the complex nature of reactive transport in fractures, a stepwise approach to identifying mechanisms controlling radionuclide transport was used. The simplest LLNL experiments included radionuclide transport through synthetic parallel-plate fractured tuff and carbonate cores. These simplified fracture transport experiments isolated matrix diffusion and sorption effects from all other fracture transport processes (fracture lining mineral sorption, heterogeneous flow, etc.). Additional fracture transport complexity was added b