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Sample records for bedrock refractive-flow cells

  1. Bedrock refractive-flow cells: A passive treatment analog to funnel-and-gate

    International Nuclear Information System (INIS)

    Dick, V.; Edwards, D.

    1997-01-01

    Funnel-and-gate technology provides a mechanism to passively treat groundwater contaminant plumes, but depends on placement of a sufficient barrier (open-quotes funnelclose quotes) in the plume flow path to channel the plume to a pass-through treatment zone (open-quotes gateclose quotes). Conventional barrier technologies limit funnel-and-gate deployment to unconsolidated overburden applications. A method has been developed which allows similar passive treatment to be applied to bedrock plumes. Rather than use barriers as the funnel, the method uses engineered bedrock zones, installed via precision blasting or other means, to refract groundwater flow along a preferred path to treatment (gate). The method requires orienting the refractive cell based on the Tangent Law and extending refractive cell limbs down gradient of the gate to disperse head and control flow. A typical Refractive-Flow cell may be open-quotes Yclose quotesshaped, with each limb 3-10 ft [1-3 m] wide and several tens to a few hundred feet [10 - 100 m] in length. Treatment takes place at the center of the X. MODFLOW modeling has been used to successfully simulate desired flow. Engineered blasting has been used at full scale application to create bedrock rubble zones for active collection/flow control for several years. The method provides a previously unavailable method to passively treat contaminated groundwater in bedrock at low cost

  2. Iowa Bedrock Geology

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — The bedrock geologic map portrays the current interpretation of the distribution of various bedrock stratigraphic units present at the bedrock surface. The bedrock...

  3. Bedrock Outcrop Points Compilation

    Data.gov (United States)

    Vermont Center for Geographic Information — A compilation of bedrock outcrops as points and/or polygons from 1:62,500 and 1:24,000 geologic mapping by the Vermont Geological Survey, the United States...

  4. Ogallala Bedrock Data Enhancement

    Data.gov (United States)

    Kansas Data Access and Support Center — This data set provides an enhanced estimate of the bedrock elevation of the Ogallala Aquifer in Kansas based on lithologic logs from a variety of sources. The data...

  5. Iowa Bedrock Topography

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — The Map of the Elevation of the Bedrock Surface in Iowa was compiled using all available data, principally information from GEOSAM, supplemented with well and boring...

  6. Iowa Bedrock Surface Elevation

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This Digital Elevation Model (DEM) of the bedrock surface elevation in Iowa was compiled using all available data, principally information from GEOSAM, supplemented...

  7. Flow in bedrock canyons.

    Science.gov (United States)

    Venditti, Jeremy G; Rennie, Colin D; Bomhof, James; Bradley, Ryan W; Little, Malcolm; Church, Michael

    2014-09-25

    Bedrock erosion in rivers sets the pace of landscape evolution, influences the evolution of orogens and determines the size, shape and relief of mountains. A variety of models link fluid flow and sediment transport processes to bedrock incision in canyons. The model components that represent sediment transport processes are increasingly well developed. In contrast, the model components being used to represent fluid flow are largely untested because there are no observations of the flow structure in bedrock canyons. Here we present a 524-kilometre, continuous centreline, acoustic Doppler current profiler survey of the Fraser Canyon in western Canada, which includes 42 individual bedrock canyons. Our observations of three-dimensional flow structure reveal that, as water enters the canyons, a high-velocity core follows the bed surface, causing a velocity inversion (high velocities near the bed and low velocities at the surface). The plunging water then upwells along the canyon walls, resulting in counter-rotating, along-stream coherent flow structures that diverge near the bed. The resulting flow structure promotes deep scour in the bedrock channel floor and undercutting of the canyon walls. This provides a mechanism for channel widening and ensures that the base of the walls is swept clear of the debris that is often deposited there, keeping the walls nearly vertical. These observations reveal that the flow structure in bedrock canyons is more complex than assumed in the models presently used. Fluid flow models that capture the essence of the three-dimensional flow field, using simple phenomenological rules that are computationally tractable, are required to capture the dynamic coupling between flow, bedrock erosion and solid-Earth dynamics.

  8. Groundwater in crystalline bedrock

    International Nuclear Information System (INIS)

    Palmqvist, K.

    1990-06-01

    The aim of this project was to make detailed descriptions of the geological conditions and the different kinds of leakage in some tunnels in Sweden, to be able to describe the presence of ground water in crystalline bedrock. The studies were carried out in TBM tunnels as well as in conventionally drilled and blasted tunnels. Thanks to this, it has been possible to compare the pattern and appearance of ground water leakage in TBM tunnels and in blasted tunnels. On the basis of some experiments in a TBM tunnel, it has been confirmed that a detailed mapping of leakage gives a good picture of the flow paths and their aquiferous qualities in the bedrock. The same picture is found to apply even in cautious blasted tunnels. It is shown that the ground water flow paths in crystalline bedrock are usually restricted to small channels along only small parts of the fractures. This is also true for fracture zones. It has also been found that the number of flow paths generally increases with the degree of tectonisation, up to a given point. With further tectonisation the bedrock is more or less crushed which, along with mineral alteration, leaves only a little space left for the formation of water channels. The largest individual flow paths are usually found in fracture zones. The total amount of ground water leakage per m tunnel is also greater in fracture zones than in the bedrock between the fracture zones. In mapping visible leakage, five classes have been distinguished according to size. Where possible, the individual leak inflow has been measured during the mapping process. The quantification of the leakage classes made in different tunnels are compared, and some quantification standards suggested. A comparison of leakage in different rock types, tectonic zones, fractures etc is also presented. (author)

  9. VT Biodiversity Project - Bedrock Classification

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) This dataset is a five category, nine sub-category classification of the bedrock units appearing on the Centennial Geologic Map of Vermont. The...

  10. Geogas in crystaline bedrock

    International Nuclear Information System (INIS)

    Hermansson, H.P.; Sjoeblom, R.; Aakerblom, G.

    1991-10-01

    The scientific literature provides conclusive evidence of gas migration through crystalline bedrock and up to the surface. In this paper, a compilation is made of various significant observations of geogas. Based on these observations, and on well-known physical and chemical principles, possible models for the behaviour of the gas are analysed and discussed. Thus, at a depth of some tens or hundreds of meters, the partial gas pressure might exceed the hydrostatic pressure, enabling the development of a gas phase. Such gas may form in fissures in the rock of perhaps 0.1 mm width. The gas deposited will attempt to minimize its surface energy. The shape assumed will thus depend on the geometrical constraints as well as on the specific surface energies between gas and water, gas and rock, and water and rock. For a small bubble, or a bubble of moderate size, these effects can be expected to make the bubble stay in place. The accumulation of gas into the gas pocket will lead to the exertion of pressure onto the uppermost part of the pocket. At some stage of gas accumulation, this pressure will become sufficient for the gas to penetrate upwards through the fissure. As the gas propagates, the hydrostatic pressure will decrease and the volume of the gas will also increase. Eventually, when the surface is reached, a burst of gas may be observed. Four mechanisms have been identified that may describe how heavy elements can be transported from considerable depths to the surface by means of gas: transport through volatile compounds that dissolve in the gas, transport by elements bonded to complexing agents that are surface active and enrich themselves onto the interface between the water and the gas, flotation (bubbles attaching themselves onto particles and lifting them) and transport by aerosols that may form when gas moves rapidly through a fracture in the rock. Finally, the paper makes some recommendations to geoscientists regarding phenomena that it may be fruitful to

  11. Formative flow in bedrock canyons

    Science.gov (United States)

    Venditti, J. G.; Kwoll, E.; Rennie, C. D.; Church, M. A.

    2017-12-01

    In alluvial channels, it is widely accepted that river channel configuration is set by a formative flow that represents a balance between the magnitude and frequency of flood flows. The formative flow is often considered to be one that is just capable of filling a river channel to the top of its banks. Flows much above this formative flow are thought to cause substantial sediment transport and rearrange the channel morphology to accommodate the larger flow. This idea has recently been extended to semi-alluvial channels where it has been shown that even with bedrock exposed, the flows rarely exceed that required to entrain the local sediment cover. What constitutes a formative flow in a bedrock canyon is not clear. By definition, canyons have rock walls and are typically incised vertically, removing the possibility of the walls being overtopped, as can occur in an alluvial channel at high flows. Canyons are laterally constrained, have deep scour pools and often have width to maximum depth ratios approaching 1, an order of magnitude lower than alluvial channels. In many canyons, there are a sequence of irregularly spaced scour pools. The bed may have intermittent or seasonal sediment cover, but during flood flows the sediment bed is entrained leaving a bare bedrock channel. It has been suggested that canyons cut into weak, well-jointed rock may adjust their morphology to the threshold for block plucking because the rock bed is labile during exceptionally large magnitude flows. However, this hypothesis does not apply to canyons cut into massive crystalline rock where abrasion is the dominant erosion process. Here, we argue that bedrock canyon morphology is adjusted to a characteristic flow structure developed in bedrock canyons. We show that the deeply scoured canyon floor is adjusted to a velocity inversion that is present at low flows, but gets stronger at high flows. The effect is to increase boundary shear stresses along the scour pool that forms in constricted

  12. Saline groundwater in crystalline bedrock

    International Nuclear Information System (INIS)

    Lampen, P.

    1992-11-01

    The State-of-art report describes research made on deep saline groundwaters and brines found in crystalline bedrock, mainly in site studies for nuclear waste disposal. The occurrence, definitions and classifications of saline groundwaters are reviewed with a special emphasis on the different theories concerning the origins of saline groundwaters. Studies of the saline groundwaters in Finland and Sweden have been reviewed more thoroughly. Also the mixing of different bodies of groundwaters, observations of the contact of saline groundwaters and permafrost, and the geochemical modelling of saline groundwaters as well as the future trends of research have been discussed. (orig.)

  13. Bedrock geologic map of Vermont

    Science.gov (United States)

    Ratcliffe, Nicholas M.; Stanley, Rolfe S.; Gale, Marjorie H.; Thompson, Peter J.; Walsh, Gregory J.; With contributions by Hatch, Norman L.; Rankin, Douglas W.; Doolan, Barry L.; Kim, Jonathan; Mehrtens, Charlotte J.; Aleinikoff, John N.; McHone, J. Gregory; Cartography by Masonic, Linda M.

    2011-01-01

    The Bedrock Geologic Map of Vermont is the result of a cooperative agreement between the U.S. Geological Survey (USGS) and the State of Vermont. The State's complex geology spans 1.4 billion years of Earth's history. The new map comes 50 years after the most recent map of the State by Charles G. Doll and others in 1961 and a full 150 years since the publication of the first geologic map of Vermont by Edward Hitchcock and others in 1861. At a scale of 1:100,000, the map shows an uncommon level of detail for State geologic maps. Mapped rock units are primarily based on lithology, or rock type, to facilitate derivative studies in multiple disciplines. The 1961 map was compiled from 1:62,500-scale or smaller maps. The current map was created to integrate more detailed (1:12,000- to 1:24,000-scale) modern and older (1:62,500-scale) mapping with the theory of plate tectonics to provide a framework for geologic, tectonic, economic, hydrogeologic, and environmental characterization of the bedrock of Vermont. The printed map consists of three oversize sheets (52 x 76 inches). Sheets 1 and 2 show the southern and northern halves of Vermont, respectively, and can be trimmed and joined so that the entire State can be displayed as a single entity. These sheets also include 10 cross sections and a geologic structure map. Sheet 3 on the front consists of descriptions of 486 map units, a correlation of map units, and references cited. Sheet 3 on the back features a list of the 195 sources of geologic map data keyed to an index map of 7.5-minute quadrangles in Vermont, as well as a table identifying ages of rocks dated by uranium-lead zircon geochronology.

  14. Bedrock Geologic Map of Woodstock, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG06-4 Thompson, P. J., 2006, Bedrock Geologic Map of Woodstock, Vermont: VGS Open-File Report VG06-4, scale 1:24,000. The bedrock geologic map...

  15. Bedrock Hydrogeology - Site investigation SFR

    Energy Technology Data Exchange (ETDEWEB)

    Oehman, Johan [Geosigma AB, Stockholm (Sweden); Bockgaard, Niclas [Golder Assoes AB, Stockholm (Sweden); Follin, Sven [SF GeoLogic AB, Taeby (Sweden)

    2012-06-15

    The Swedish Nuclear Fuel and Waste Management Company (SKB) has conducted site investigations for a planned extension of the existing final repository for short-lived radioactive waste (SFR). This report presents an integrated analysis and interpretation of the historic data from the existing SFR (1980 - 1986), as well as, from the recent investigations for the planned extension of SFR (2008 - 2009). The primary objective is to establish a conceptual hydrogeological model of the bedrock for safety assessment and design analyses. Analyses and interpretations of all (old and new) hydraulic data are analysed with regard to the recently developed geological deformation zone model of the SFR model domain (Curtis et al. 2011). The methodology used by Curtis et al. (2011) has focussed on magnetic anomalies and deformation zone intercepts with ground surface greater than 300 m. In the hydrogeological modelling, however, it has been considered important to also explore the occurrence and characteristics of shallow horizontal to sub-horizontal structures (sheet joints) inside the SFR model domain. Such structures are of considerable importance for the hydrogeology in the uppermost c. 150 m of bedrock in SDM-Site Forsmark; hence the term Shallow Bedrock Aquifer was used to emphasise their hydraulic significance. In this study, the acronym SBA-structure is used for horizontal structures identified in the hydrogeological modelling. In addition to the predominantly steeply dipping geological deformation zones, eight so-called SBA-structures are modelled deterministically in the hydrogeological model. The SBA-structures are envisaged as hydraulically heterogeneous and composed of clusters of minor gently dipping to horizontal fractures rather than extensive single features. A type of structures that is partly included in the definition of the SBA-structures is the Unresolved Possible Deformations Zone (Unresolved PDZ) intercepts identified by Curtis et al. (2011). The Unresolved

  16. Depth to Bedrock: Isopach of Unconsolidated Materials

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This vector dataset gives the approximate depth to bedrock (in feet) from Iowa's current land surface. This 50 foot isopach data was derived from the Digital...

  17. SFR site investigation. Bedrock Hydrogeochemistry

    International Nuclear Information System (INIS)

    Nilsson, Ann-Chatrin; Tullborg, Eva-Lena; Smellie, John; Gimeno, Maria J.; Gomez, Javier B.; Auque, Luis F.; Sandstroem, Bjoern; Pedersen, Karsten

    2011-11-01

    There are plans that the final repository for low and intermediate level radioactive waste, SFR, located about 150 km north of Stockholm, will be extended. Geoscientific studies to define and characterise a suitable bedrock volume for the extended repository have been carried out from 2007 to 2011, and have included the drilling and evaluation of seven new core drilled and four percussion boreholes. These new data, together with existing data extending back to 1985, have been interpreted and modelled in order to provide the necessary information for safety assessment and repository design. This report presents the final hydrogeochemical site description for the SFR site, and will constitute a background report for the integrated site description (the SFR Site Descriptive Model version 1.0) together with corresponding reports from the geological and hydrogeological disciplines. Most of the hydrogeochemical data from the field investigations consist of major ions and isotopes together with sporadic gas, microbe and measured redox data. Despite the close proximity of the Forsmark site, few data from this source are of relevance because of the shallow nature of the SFR site, the fact that SFR is located beneath the Baltic Sea and also the drawdown/upconing impacts of its construction on the hydrogeochemistry. This artificially imposed dynamic flow system is naturally more prevalent along major deformation fracture zones of higher transmissivity, whilst lower transmissive fractures together with the less transmissive bedrock masses between major deformation zones, still retain some evidence of the natural groundwater mixing patterns established prior to the SFR construction. The groundwaters in the SFR dataset cover a depth down to -250 m.a.s.l. with single sampling locations at -300 and -400 m.a.s.l. and represent a relatively limited salinity range (1,500 to 5,500 mg/L chloride). However, the δ 18 O values show a wide variation (-15.5 to -7.5 per mille V

  18. SFR site investigation. Bedrock Hydrogeochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Ann-Chatrin [Geosigma AB, Uppsala (Sweden); Tullborg, Eva-Lena [Terralogica AB, Graabo (Sweden); Smellie, John [Conterra AB, Uppsala (Sweden); Gimeno, Maria J.; Gomez, Javier B.; Auque, Luis F. [Univ. of Zaragoza, Zaragoza (Spain); Sandstroem, Bjoern [WSP Sverige AB, Goeteborg (Sweden); Pedersen, Karsten [Micans AB, Moelnlycke (Sweden)

    2011-11-15

    There are plans that the final repository for low and intermediate level radioactive waste, SFR, located about 150 km north of Stockholm, will be extended. Geoscientific studies to define and characterise a suitable bedrock volume for the extended repository have been carried out from 2007 to 2011, and have included the drilling and evaluation of seven new core drilled and four percussion boreholes. These new data, together with existing data extending back to 1985, have been interpreted and modelled in order to provide the necessary information for safety assessment and repository design. This report presents the final hydrogeochemical site description for the SFR site, and will constitute a background report for the integrated site description (the SFR Site Descriptive Model version 1.0) together with corresponding reports from the geological and hydrogeological disciplines. Most of the hydrogeochemical data from the field investigations consist of major ions and isotopes together with sporadic gas, microbe and measured redox data. Despite the close proximity of the Forsmark site, few data from this source are of relevance because of the shallow nature of the SFR site, the fact that SFR is located beneath the Baltic Sea and also the drawdown/upconing impacts of its construction on the hydrogeochemistry. This artificially imposed dynamic flow system is naturally more prevalent along major deformation fracture zones of higher transmissivity, whilst lower transmissive fractures together with the less transmissive bedrock masses between major deformation zones, still retain some evidence of the natural groundwater mixing patterns established prior to the SFR construction. The groundwaters in the SFR dataset cover a depth down to -250 m.a.s.l. with single sampling locations at -300 and -400 m.a.s.l. and represent a relatively limited salinity range (1,500 to 5,500 mg/L chloride). However, the {delta}{sup 18}O values show a wide variation (-15.5 to -7.5 per mille V

  19. The role of bedrock in creating habitat in temperate watercourses

    Science.gov (United States)

    Entwistle, N. S.; Heritage, G. L.; Milan, D. J.

    2016-12-01

    Bedrock influenced rivers are a relatively common yet little studied river type across temperate regions, occurring predominantly in upland areas and in areas where isostatic rebound has promoted rapid watercourse downcutting through resistant bedrock. The presence of bedrock in the bed and banks exerts a major influence on channel development, controlling local flow hydraulics and subsequently influencing in-channel and valley bottom sedimentary feature development. This paper summarises extensive field audit evidence of bedrock influenced features on watercourses in the UK to characterise the diverse morphology of bedrock influenced channels and reviews the bedrock induced hydraulic influences on their development and maintenance. Such features include bedrock waterfalls, steps, rapids and cascades and associated alluvial deposits forming lee bars, bedrock obstruction bars, plunge pool bars and fine sediment drapes and veneers. Bedrock influence on valley bottom features is also reviewed and a functional typology is developed for this river type based on the feature assemblage and degree of bedrock/alluvial influence.

  20. Cyclic steps incised on experimental bedrock

    Science.gov (United States)

    Yokokawa, M.; Kyogoku, A.; Kotera, A.; Izumi, N.

    2013-12-01

    In rivers flowing in mountain areas, a series of steps are often observed on bedrock. They are thought to be cyclic steps formed due to erosion of bedrock, which should be driven by abrasion due to bedload sediment transport. We demonstrated a series of flume experiments of the formation of cyclic steps on bedrock by abrasion due to bedload transportation using weak mortar as the model bedrock. We also compared the shapes of the steps reproduced in the experiments with those obtained in the analysis. The experiments were conducted using a 1.5 m long, 2 cm wide, and 20 cm deep flume made of glass in Osaka Institute of Technology. The flume has 10-cm-high weirs at both ends, so that there is a 10-cm-deep reservoir. We put mortar into the reservoir and hardened it. In order to make a highly erodible mortar, we casted the mortar with extremely low amount of cement. The ratio of cement, sand (0.2 mm in diameter), and water is x:150:50 (x ranges 1-3). The flume is tilted by 10 degrees. The water and colored sand is supplied from a head tank to the upstream end of the flume, flows on 'model bedrock' in the flume, and was dropped from the downstream end. We observed morphological changes of the surface of the bedrock by photos. We also used a laser displacement sensor to measure the surface topography of the 'model bedrock' before and after each run. The configuration of steps largely depends on the hardness of model bedrocks. In the case of the softest model bedrock (cement-sand-water ratio is 1:150:50) with small amount of sand, long-drawn potholes tend to be formed. Clear cyclic steps are formed on harder model bedrocks with large cement-sand-water ratios such as 2:150:50 and 3:150:50. When a series of steps are formed on the bed, typical wavelength and wave height are approximately 20 cm, and 2 - 3 cm, respectively. The general shape of a step is characterized by a relatively long downward-inclined slope just upstream of a short upward-inclined slope. The feature of

  1. Bedrock Geologic Map of Vermont - Dikes

    Data.gov (United States)

    Vermont Center for Geographic Information — The bedrock geology was last mapped at a statewide scale 50 years ago at a scale of 1:250,000 (Doll and others, 1961). The 1961 map was compiled from 1:62,500-scale...

  2. Mapping Bedrock Topography using Electromagnetic Profiling ...

    African Journals Online (AJOL)

    Electromagnetic profiling method was used in Echara Unuhu, within the Abakaliki Urban, to map the bedrock topography which also aids us to determine the position of the deepest fractured shale where a productive borehole will be constructed The area under study is within the Abakaliki Shales Geologic Formation.

  3. Rural Community Development: Bedrock for National Development ...

    African Journals Online (AJOL)

    This paper advocates that community development is the bedrock for national development. For any meaningful development to take place, whether national or global development must have its building blocks or firm-root in rural development. However, the rural communities are characterized by isolation from ideas and ...

  4. Bedrock Geologic Map of Vermont - Units

    Data.gov (United States)

    Vermont Center for Geographic Information — The bedrock geology was last mapped at a statewide scale 50 years ago at a scale of 1:250,000 (Doll and others, 1961). The 1961 map was compiled from 1:62,500-scale...

  5. IN SITU MEASUREMENT OF BEDROCK EROSION

    Directory of Open Access Journals (Sweden)

    D. H. Rieke-Zapp

    2012-07-01

    Full Text Available While long term erosion rates of bedrock material may be estimated by dating methods, current day erosion rates are – if at all available – based on rough estimates or on point measurements. Precise quantification of short term erosion rates are required to improve our understanding of short term processes, for input in landscape evolution models, as well as for studying the mechanics and efficiency of different erosion processes in varying geomorphological settings. Typical current day erosion rates in the European Alps range from sub-millimetre to several millimetres per year depending on the dominant erosion processes. The level of surveying accuracy required for recurring sub-millimetre to millimetre measurements in the field is demanding. A novel surveying setup for in-situ measurement of bedrock erosion was tested recently in three different locations in Switzerland. Natural bedrock was investigated in the Gornera gorge close to Zermatt. Further on, bedrock samples were installed in exposed locations in the Erlenbach research watershed close to Einsiedeln, and in the Illgraben debris flow channel, located in the Canton Schwyz and Valais, respectively. A twofold measurement approach was chosen for all locations. For the first setup control points providing an absolute reference frame for recurrent measurements were embedded close to the area of interest. Close range photogrammetry was applied to measure surface changes on the bedrock samples. The precision for surface measurements in the field was 0.1 mm (1 σ and thus suitable for the application. The equipment needed for the surveys can easily be carried to the field. At one field site a structured light scanner was used along with the photogrammetric setup. Although the current generation of structured light scanners appeared less suitable for field application, data acquisition was much faster and checking the data for completeness in the field was straight forward. The latest

  6. Can Springs Cut Valleys Into Bedrock?

    Science.gov (United States)

    Lamb, M. P.; Dietrich, W. E.

    2004-12-01

    Valleys formed from groundwater sapping are thought to have a characteristic form including steep walls, flat floors, and amphitheatre-like heads. Observations of these features on Earth and Mars have led to the morphologic-based interpretation that groundwater sapping is an important valley forming process. This interpretation has significant implications for Mars in particular because it has been used to constrain Martian hydrology and the associated prospects for life. However, a mechanistic understanding of sapping erosion has only been demonstrated for granular mediums (i.e. sand). Many of the "sapping" valleys on Earth and (likely) Mars have been carved into bedrock, and the extension of previous work to bedrock erosion is unclear. To our knowledge, a process-based understanding of seepage erosion in bedrock does not exist, even though it is thought to be a first order geomorphic process on Earth and Mars. In order to address this knowledge gap, we are currently investigating Box Canyon, Idaho. Box Canyon, developed in the Snake River Plain, has many of the morphologic features often associated with sapping valleys. In addition, it was carved into basaltic bedrock and has a large spring emanating from its amphitheatre-like head, making it an ideal candidate for a sapping origin. There is currently no overland flow contribution to the canyon; however, based on mapping bedrock scours, a paleo-flood from an unknown upslope source did enter the canyon (and perhaps carved it). We present some first order hydraulic measurements, sediment transport calculations, and field observations to try and constrain the types of flows needed to carve Box Canyon. These flows could conceivably be derived from expansion of the current spring. Direct observation at the head of the canyon has not yet indicated how sapping could be responsible for the erosion of the headwall. We are using various dating techniques to constrain the timing and rate of headwall migration to constrain

  7. In Situ Measurement of Bedrock Erosion

    Science.gov (United States)

    Rieke-Zapp, D. H.; Beer, A.; Turowski, J. M.; Campana, L.

    2012-07-01

    While long term erosion rates of bedrock material may be estimated by dating methods, current day erosion rates are - if at all available - based on rough estimates or on point measurements. Precise quantification of short term erosion rates are required to improve our understanding of short term processes, for input in landscape evolution models, as well as for studying the mechanics and efficiency of different erosion processes in varying geomorphological settings. Typical current day erosion rates in the European Alps range from sub-millimetre to several millimetres per year depending on the dominant erosion processes. The level of surveying accuracy required for recurring sub-millimetre to millimetre measurements in the field is demanding. A novel surveying setup for in-situ measurement of bedrock erosion was tested recently in three different locations in Switzerland. Natural bedrock was investigated in the Gornera gorge close to Zermatt. Further on, bedrock samples were installed in exposed locations in the Erlenbach research watershed close to Einsiedeln, and in the Illgraben debris flow channel, located in the Canton Schwyz and Valais, respectively. A twofold measurement approach was chosen for all locations. For the first setup control points providing an absolute reference frame for recurrent measurements were embedded close to the area of interest. Close range photogrammetry was applied to measure surface changes on the bedrock samples. The precision for surface measurements in the field was 0.1 mm (1 σ) and thus suitable for the application. The equipment needed for the surveys can easily be carried to the field. At one field site a structured light scanner was used along with the photogrammetric setup. Although the current generation of structured light scanners appeared less suitable for field application, data acquisition was much faster and checking the data for completeness in the field was straight forward. The latest generation of compact

  8. Bedrock Geologic Map of the Hinesburg Quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from Thompson, P., Thompson, T.B., and Doolan, B., 2004, Bedrock Geology of the Hinesburg quadrangle, Vermont. The bedrock geologic map data at a scale...

  9. Global Bedrock Geology and River Chemistry

    Science.gov (United States)

    Peucker-Ehrenbrink, B.; Miller, M. W.

    2002-12-01

    The lack of modern quantitative estimates of the Earth`s surface geology, one of the key parameters influencing river (and ocean) chemistry, is striking. Most published estimates of area-age relationships of sedimentary bedrock, for instance, were published before the 1980s, were based on less detailed geologic maps often decades older, and used techniques such as cutting and weighting age correlative map units or point counting at fairly coarse resolution (Higgs, 1949; Gilluly, 1969; Blatt and Jones, 1975; Ronov, 1980). Even more recent estimates (e.g., Berry and Wilkinson, 1994) are based on data predating the 1980s (Cook and Bally, 1975; Ronov, 1980). In an attempt to gain quantitative understanding of the link between surface geology (bedrock chemistry and weatherability) and river (and ocean) chemistry we have initiated a global assessment of the Earth`s surface geology that is based on the latest digital geologic maps using modern geographic information system technology (Environmental Systems Research Institute`s ArcInfo software). To date we have completed analysis of three digital data sets: 1) the geologic map of the conterminous United States of America by King and Beikman (1974; 1:2,500,000; spatial resolution ~600 km2 per polygon), made available in digital format by the USGS, 2) the geologic map of Alaska by Beikman (1980; 1:2,5000,000; ~300 km2 per polygon), also available in digital form through the USGS, and 3) the geologic map of Canada that is based on a revised and updated version of the geologic map by Douglas (1969; 1:5,000,000; ~780 km2 per polygon), made available in digital form by the Geologic Survey of Canada. The data reveal, among others, the area-age relationship of sedimentary, volcanic, intrusive and metamorphic rocks at unprecedented temporal and spatial resolution. The data also provide quantitative estimates of the abundance of major rock types: sedimentary rocks make up 83% (US; 69.7% stratified, mostly marine and 13

  10. Cokriging surface elevation and seismic refraction data for bedrock topography

    International Nuclear Information System (INIS)

    Nyquist, J.E.; Doll, W.E.; Davis, R.K.; Hopkins, R.A.

    1992-01-01

    Analysis of seismic refraction data collected at a proposed site of the Advanced Neutron Source (ANS) Facility showed a strong correlation between surface and bedrock topography. By combining seismically determined bedrock elevation data with surface elevation data using cokriging, we were able to significantly improve our map of bedrock topography without collecting additional seismic data

  11. New approaches to subglacial bedrock drilling technology

    Science.gov (United States)

    Talalay, Pavel; Sun, Youhong; Zhao, Yue; Xue, Jun; Chen, Chen; Markov, Alexey; Xu, Huiwen; Gong, Wenbin; Han, Wei; Zheng, Zhichuan; Cao, Pinlu; Wang, Rusheng; Zhang, Nan; Yu, Dahui; Fan, Xiaopeng; Hu, Zhengyi; Yang, Cheng; Han, Lili; Sysoev, Mikhail

    2013-04-01

    Drilling to bedrock of ice sheets and glaciers offers unique opportunities to research processes acting at the bed for paleo-climatic and paleo-environmental recording, basal sliding studies, subglacial geology and tectonics investigations, prospecting and exploration for minerals covered by ice. Retrieving bedrock samples under ice sheets and glaciers is a very difficult task. Drilling operations are complicated by extremely low temperature at the surface of, and within glaciers, and by glacier flow, the absence of roads and infrastructures, storms, winds, snowfalls, etc. In order to penetrate through the ice sheet or glacier up to the depth of at least 1000 m and to pierce the bedrock to the depth of several meters from ice - bedrock boundary the development activity already has been started in Polar Research Center at Jilin University, China. All drilling equipment (two 50-kW diesel generators, winch, control desk, fluid dumping station, etc.) is installed inside a movable sledge-mounted warm-keeping and wind-protecting drilling shelter that has dimensions of 8.8 ×2.8 × 3.0 m. Mast has two positions: horizontal for transportation and vertical working position (mast height is 12 m). Drilling shelter can be transported to the chosen site with crawler-tractor, aircraft or helicopter. In case of carriage by air the whole drilling shelter was designed to be disassembled into pieces "small" enough to ship by aircraft. Weight and sizes of each component has been minimized to lower the cost of transportation and to meet weight restrictions for transportation. Total weight of drilling equipment (without drilling fluid) is near 15 tons. Expected time of assembling and preparing for drilling is 2 weeks. If drilling shelter is transported with crawler-tractor (for example, in Antarctic traverses) all equipment is ready to start drilling immediately upon arrival to the site. To drill through ice and bedrock a new, modified version of the cable-suspended electromechanical

  12. Durable terrestrial bedrock predicts submarine canyon formation

    Science.gov (United States)

    Smith, Elliot; Finnegan, Noah J.; Mueller, Erich R.; Best, Rebecca J.

    2017-01-01

    Though submarine canyons are first-order topographic features of Earth, the processes responsible for their occurrence remain poorly understood. Potentially analogous studies of terrestrial rivers show that the flux and caliber of transported bedload are significant controls on bedrock incision. Here we hypothesize that coarse sediment load could exert a similar role in the formation of submarine canyons. We conducted a comprehensive empirical analysis of canyon occurrence along the West Coast of the contiguous United States which indicates that submarine canyon occurrence is best predicted by the occurrence of durable crystalline bedrock in adjacent terrestrial catchments. Canyon occurrence is also predicted by the flux of bed sediment to shore from terrestrial streams. Surprisingly, no significant correlation was observed between canyon occurrence and the slope or width of the continental shelf. These findings suggest that canyon incision is promoted by greater yields of durable terrestrial clasts to the shore.

  13. Durable Terrestrial Bedrock Predicts Submarine Canyon Formation

    Science.gov (United States)

    Smith, M. Elliot; Finnegan, Noah J.; Mueller, Erich R.; Best, Rebecca J.

    2017-10-01

    Though submarine canyons are first-order topographic features of Earth, the processes responsible for their occurrence remain poorly understood. Potentially analogous studies of terrestrial rivers show that the flux and caliber of transported bedload are significant controls on bedrock incision. Here we hypothesize that coarse sediment load could exert a similar role in the formation of submarine canyons. We conducted a comprehensive empirical analysis of canyon occurrence along the West Coast of the contiguous United States which indicates that submarine canyon occurrence is best predicted by the occurrence of durable crystalline bedrock in adjacent terrestrial catchments. Canyon occurrence is also predicted by the flux of bed sediment to shore from terrestrial streams. Surprisingly, no significant correlation was observed between canyon occurrence and the slope or width of the continental shelf. These findings suggest that canyon incision is promoted by greater yields of durable terrestrial clasts to the shore.

  14. Localized bedrock aquifer distribution explains discharge from a headwater catchment

    Science.gov (United States)

    Kosugi, Ken'ichirou; Fujimoto, Masamitsu; Katsura, Shin'ya; Kato, Hiroyuki; Sando, Yoshiki; Mizuyama, Takahisa

    2011-07-01

    Understanding a discharge hydrograph is one of the leading interests in catchment hydrology. Recent research has provided credible information on the importance of bedrock groundwater on discharge hydrographs from headwater catchments. However, intensive monitoring of bedrock groundwater is rare in mountains with steep topography. Hence, how bedrock groundwater controls discharge from a steep headwater catchment is in dispute. In this study, we conducted long-term hydrological observations using densely located bedrock wells in a headwater catchment underlain by granitic bedrock. The catchment has steep topography affected by diastrophic activities. Results showed a fairly regionalized distribution of bedrock aquifers within a scale of tens of meters, consisting of upper, middle, and lower aquifers, instead of a gradual and continuous decline in water level from ridge to valley bottom. This was presumably attributable to the unique bedrock structure; fault lines developed in the watershed worked to form divides between the bedrock aquifers. Spatial expanse of each aquifer and the interaction among aquifers were key factors to explain gentle and considerable variations in the base flow discharge and triple-peak discharge responses of the observed hydrograph. A simple model was developed to simulate the discharge hydrograph, which computed each of the contributions from the soil mantle groundwater, from the lower aquifer, and from the middle aquifer to the discharge. The modeling results generally succeeded in reproducing the observed hydrograph. Thus, this study demonstrated that understanding regionalized bedrock aquifer distribution is pivotal for explaining discharge hydrograph from headwater catchments that have been affected by diastrophic activities.

  15. Bedrock model of the Olkiluoto area

    International Nuclear Information System (INIS)

    Saksa, P.; Paananen, M.; Paulamaeki, S.; Anttila, P.; Front, K.; Pitkaenen, P.; Hassinen, P.; Ylinen, A.

    1993-07-01

    Site investigations were carried out at Olkiluoto (in Finland) in 1987-1992 in accordance with an investigation programme drawn up by Teollisuuden Voima Oy (TVO). The site was modelled in terms of rock types, fracturing, fracture structures and geohydrological conditions, the main focus of examination was on fracturing and associated hydraulic conductivity. The various properties of the bedrock structures were classified by means of a three-dimensional model. The descriptions of the models were gathered in a computer system for illustration and storage purposes. The rock types at Olkiluoto are migmatite, which may be divided into mica gneiss and veined gneiss, and also tonalite and coarse-grained migmatite granite (pegmatite). (64 refs., 65 figs.)

  16. Geology, Bedrock - BEDROCK_TOPOGRAPHY_MM36_IN: Bedrock Topography Contours, Indiana (Indiana Geological Survey, 1:500,000, Line Shapefile)

    Data.gov (United States)

    NSGIC State | GIS Inventory — Bedrock topography was converted from the original published map, Indiana Geological Survey Miscellaneous Map 36. The contours define the elevation/topography of the...

  17. Using PHREEQC to simulate solute transport in fractured bedrock.

    Science.gov (United States)

    Lipson, David S; McCray, John E; Thyne, Geoffrey D

    2007-01-01

    The geochemical computer model PHREEQC can simulate solute transport in fractured bedrock aquifers that can be conceptualized as dual-porosity flow systems subject to one-dimensional advective-dispersive transport in the bedrock fractures and diffusive transport in the bedrock matrix. This article demonstrates how the physical characteristics of such flow systems can be parameterized for use in PHREEQC, it provides a method for minimizing numerical dispersion in PHREEQC simulations, and it compares PHREEQC simulations with results of an analytical solution. The simulations assumed a dual-porosity conceptual model involving advective-reactive-dispersive transport in the mobile zone (bedrock fracture) and diffusive-reactive transport in the immobile zone (bedrock matrix). The results from the PHREEQC dual-porosity transport model that uses a finite-difference approach showed excellent agreement compared with an analytical solution.

  18. A self-regulating model of bedrock river channel geometry

    Science.gov (United States)

    Stark, C. P.

    2006-02-01

    The evolution of many mountain landscapes is controlled by the incision of bedrock river channels. While the rate of incision is set by channel shape through its mediation of flow, the channel shape is itself set by the history of bedrock erosion. This feedback between channel geometry and incision determines the speed of landscape response to tectonic or climatic forcing. Here, a model for the dynamics of bedrock channel shape is derived from geometric arguments, a normal flow approximation for channel flow, and a threshold bed shear stress assumption for bedrock abrasion. The model dynamics describe the competing effects of channel widening, tilting, bending, and variable flow depth. Transient solutions suggest that channels may take ~1-10 ky to adapt to changes in discharge, implying that channel disequilibrium is commonplace. If so, landscape evolution models will need to include bedrock channel dynamics if they are to probe the effects of climate change.

  19. A probabilistic framework for the cover effect in bedrock erosion

    Science.gov (United States)

    Turowski, Jens M.; Hodge, Rebecca

    2017-06-01

    The cover effect in fluvial bedrock erosion is a major control on bedrock channel morphology and long-term channel dynamics. Here, we suggest a probabilistic framework for the description of the cover effect that can be applied to field, laboratory, and modelling data and thus allows the comparison of results from different sources. The framework describes the formation of sediment cover as a function of the probability of sediment being deposited on already alluviated areas of the bed. We define benchmark cases and suggest physical interpretations of deviations from these benchmarks. Furthermore, we develop a reach-scale model for sediment transfer in a bedrock channel and use it to clarify the relations between the sediment mass residing on the bed, the exposed bedrock fraction, and the transport stage. We derive system timescales and investigate cover response to cyclic perturbations. The model predicts that bedrock channels can achieve grade in steady state by adjusting bed cover. Thus, bedrock channels have at least two characteristic timescales of response. Over short timescales, the degree of bed cover is adjusted such that the supplied sediment load can just be transported, while over long timescales, channel morphology evolves such that the bedrock incision rate matches the tectonic uplift or base-level lowering rate.

  20. Oskarshamn site investigation. Bedrock geology - overview and excursion guide

    Energy Technology Data Exchange (ETDEWEB)

    Wahlgren, Carl-Henric (Geological Survey of Sweden, Uppsala (Sweden))

    2010-09-15

    Bearing in mind the significance of the bedrock data from the ground surface for the geological 3D modelling work, SKB decided to present excursion guides that serve in the demonstration of the bedrock geology at the ground surface in both the Forsmark and Laxemar-Simpevarp (this guide) areas. An excursion guide is also available for the Olkiluoto area in south-western Finland, which has been selected for the construction of a repository for the disposal of highly radioactive, spent nuclear fuel. The current excursion guide presents the bedrock geology and describes in detail the character of the bedrock at eight representative outcrops or outcrop areas at the ground surface in the site investigation area at Laxemar-Simpevarp and at one locality north of this area, i.e. at a total of nine localities

  1. Forsmark site investigation. Bedrock geology - overview and excursion guide

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, Michael B. (Geological Survey of Sweden, Uppsala (Sweden))

    2010-09-15

    Bearing in mind the significance of the bedrock data from the ground surface for the geological 3D modelling work, SKB decided to present excursion guides that serve in the demonstration of the bedrock geology at the ground surface in both the Forsmark (this guide) and Laxemar-Simpevarp areas. An excursion guide is also available for the Olkiluoto area in south-western Finland, which has been selected for the construction of a repository for the disposal of highly radioactive, spent nuclear fuel in Finland. The current excursion guide presents the bedrock geology and describes in detail the character of the bedrock at ten representative outcrops or outcrop areas at the ground surface in the site investigation area at Forsmark. All localities are located within or immediately adjacent to the proposed repository volume selected by SKB

  2. Bedrock Geologic Map of Charlotte,�Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG09-5 Gale, M., Kim, J., Earle, H., Clark, A., Smith, T., and Petersen, K., 2009, Bedrock Geologic Map of Charlotte, Vermont: VGS Open-File Report...

  3. Oskarshamn site investigation. Bedrock geology - overview and excursion guide

    International Nuclear Information System (INIS)

    Wahlgren, Carl-Henric

    2010-09-01

    Bearing in mind the significance of the bedrock data from the ground surface for the geological 3D modelling work, SKB decided to present excursion guides that serve in the demonstration of the bedrock geology at the ground surface in both the Forsmark and Laxemar-Simpevarp (this guide) areas. An excursion guide is also available for the Olkiluoto area in south-western Finland, which has been selected for the construction of a repository for the disposal of highly radioactive, spent nuclear fuel. The current excursion guide presents the bedrock geology and describes in detail the character of the bedrock at eight representative outcrops or outcrop areas at the ground surface in the site investigation area at Laxemar-Simpevarp and at one locality north of this area, i.e. at a total of nine localities

  4. Digital compilation bedrock geologic map of the Warren quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG95-4A Walsh, GJ, Haydock, S, Prewitt, J, Kraus, J, Lapp, E, O'Loughlin, S, and Stanley, RS, 1995, Digital compilation bedrock geologic map of the...

  5. Digital bedrock geologic map of the Cavendish quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG95-203A Ratcliffe, NM, 1995,�Digital bedrock geologic map of the Cavendish quadrangle, Vermont: USGS Open-File Report 95-203, 2 plates, scale...

  6. Bedrock Geologic Map of the Bristol, VT Quadrangle

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital data from VG13-1 Kim, J, Weber, E, and Klepeis, K, 2013, Bedrock Geologic Map of the Bristol, VT Quadrangle: Vermont Geological Survey Open File Report...

  7. Roosevelt Island Bedrock and Surface Elevations, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of bedrock and surface elevation readings taken by ground penetrating radar and Global Positioning System (GPS) on Roosevelt Island, an ice...

  8. Bedrock Geologic Map of the Jay Peak, VT Quadrangle

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital data from VG99-1 Compilation bedrock geologic map of the Jay Peak quadrangle, Compiled by B. Doolan, 1999: VGS Open-File Report VG99-1, 1 plate, scale...

  9. Forsmark site investigation. Bedrock geology - overview and excursion guide

    International Nuclear Information System (INIS)

    Stephens, Michael B.

    2010-09-01

    Bearing in mind the significance of the bedrock data from the ground surface for the geological 3D modelling work, SKB decided to present excursion guides that serve in the demonstration of the bedrock geology at the ground surface in both the Forsmark (this guide) and Laxemar-Simpevarp areas. An excursion guide is also available for the Olkiluoto area in south-western Finland, which has been selected for the construction of a repository for the disposal of highly radioactive, spent nuclear fuel in Finland. The current excursion guide presents the bedrock geology and describes in detail the character of the bedrock at ten representative outcrops or outcrop areas at the ground surface in the site investigation area at Forsmark. All localities are located within or immediately adjacent to the proposed repository volume selected by SKB

  10. Digital compilation bedrock geologic map of the Lincoln quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG95-5A Stanley, R, DelloRusso, V, Haydock, S, Lapp, E, O'Loughlin, S, Prewitt, J,and Tauvers, PR, 1995, Digital compilation bedrock geologic map...

  11. Digital compilation bedrock geologic map of the Milton quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG95-8A Dorsey, R, Doolan, B, Agnew, PC, Carter, CM, Rosencrantz, EJ, and Stanley, RS, 1995, Digital compilation bedrock geologic map of the Milton...

  12. Greenland 5 km DEM, Ice Thickness, and Bedrock Elevation Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — A Digital Elevation Model (DEM), ice thickness grid, and bedrock elevation grid of Greenland acquired as part of the PARCA program are available in ASCII text format...

  13. Hydrogeology - AQUIFER_SYSTEMS_BEDROCK_IDNR_IN: Bedrock Aquifer Systems of Indiana (Indiana Department of Natural Resources, 1:500,000, Polygon Shapefile)

    Data.gov (United States)

    NSGIC State | GIS Inventory — AQUIFER_SYSTEMS_BEDROCK_IDNR_IN is a polygon shapefile that shows bedrock aquifer systems of the State of Indiana. The source scale of the map depicting the aquifers...

  14. Spatial bedrock erosion distribution in a natural gorge

    Science.gov (United States)

    Beer, A. R.; Turowski, J. M.; Kirchner, J. W.

    2015-12-01

    Quantitative analysis of morphological evolution both in terrestrial and planetary landscapes is of increasing interest in the geosciences. In mountainous regions, bedrock channel formation as a consequence of the interaction of uplift and erosion processes is fundamental for the entire surface evolution. Hence, the accurate description of bedrock channel development is important for landscape modelling. To verify existing concepts developed in the lab and to analyse how in situ channel erosion rates depend on the interrelations of discharge, sediment transport and topography, there is a need of highly resolved topographic field data. We analyse bedrock erosion over two years in a bedrock gorge downstream of the Gorner glacier above the town of Zermatt, Switzerland. At the study site, the Gornera stream cuts through a roche moutonnée in serpentine rock of 25m length, 5m width and 8m depth. We surveyed bedrock erosion rates using repeat terrestrial laser scanning (TLS) with an average point spacing of 5mm. Bedrock erosion rates in direction of the individual surface normals were studied directly on the scanned point clouds applying the M3C2 algorithm (Lague et al., 2013, ISPRS). The surveyed erosion patterns were compared to a simple stream erosivity visualisation obtained from painted bedrock sections at the study location. Spatially distributed erosion rates on bedrock surfaces based on millions of scan points allow deduction of millimeter-scale mean annual values of lateral erosion, incision and downstream erosion on protruding streambed surfaces. The erosion rate on a specific surface point is shown to depend on the position of this surface point in the channel's cross section, its height above the streambed and its spatial orientation to the streamflow. Abrasion by impacting bedload was likely the spatially dominant erosion process, as confirmed by the observed patterns along the painted bedrock sections. However, a single plucking event accounted for the half

  15. Analysis of overdeepened valleys using the digital elevation model of the bedrock surface of Northern Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, P.

    2010-11-15

    Based on surface and borehole information, together with pre-existing regional and local interpretations, a 7,150 square kilometre Raster Digital Elevation Model (DEM) of the bedrock surface of northern Switzerland was constructed using a 25 m cell size. This model represents a further important step in the understanding of Quaternary sediment distribution and is open to a broad field of application and analysis, including hydrogeological, geotechnical and geophysical studies as well as research in the field of Pleistocene landscape evolution. An analysis of the overdeepened valleys in the whole model area and, more specifically in the Reuss area, shows that, in most cases, overdeepening is restricted to the areas covered by the Last Glaciation Maximum (LGM). However, at various locations relatively narrow overdeepened valleys outreach the tongue basins and the LGM ice shield limits. Therefore, an earlier and further-reaching glacial event has probably contributed significantly to the overdeepening of these valleys. No significant overdeepening has been identified downstream of Boettstein (Aare) and Kaiserstuhl (Rhine), although the ice extended considerably further downstream, at least during the most extensive glaciation. Except for the bedrock between Brugg and Boettstein, no overdeepened valleys are found significantly north of the outcrop of Mesozoic limestone of the Folded and Tabular Jura. A detailed analysis of the Reuss area shows that the Lake and Suhre valleys are separated from the Emmen-Gisikon Reuss valley basin by a significant bedrock barrier. The individual bedrock valleys are divided into several sub-basins, indicating a multiphase evolution of the valleys. Some of the swells or barriers separating the sub-basins coincide with known late LGM retreat stages. In the Suhre valley, an old fluvial valley floor with restricted overdeepened sections is documented. (author)

  16. Assessing the velocity of the groundwater flow in bedrock fractures

    International Nuclear Information System (INIS)

    Taivassalo, V.; Poteri, A.

    1994-10-01

    Teollisuuden Voima Oy (TVO) is studying the crystalline bedrock in Finland for the final disposal of the spent nuclear fuel from its two reactors in Olkiluoto. Preliminary site investigations for five areas were carried out during 1987-1992. One part of the investigation programme was three-dimensional groundwater flow modelling. The numerical site-specific flow simulations were based on the concept of an equivalent porous continuum. The results include hydraulic head distributions, average groundwater flow rate routes. In this study, a novel approach was developed to evaluate the velocities of the water particles flowing in the fractured bedrock. (17 refs., 15 figs., 5 tabs.)

  17. Bedrock hydrogeology Forsmark. Site descriptive modelling, SDM-Site Forsmark

    International Nuclear Information System (INIS)

    Follin, Sven

    2008-12-01

    The Swedish Nuclear Fuel and Waste Management Company (SKB) has conducted site investigations at two different locations, the Forsmark and Laxemar-Simpevarp areas, with the objective of siting a final repository for spent nuclear fuel according to the KBS-3 concept. Site characterisation should provide all data required for an integrated evaluation of the suitability of the investigated site and an important component in the characterisation work is the development of a hydrogeological model. The hydrogeological model is used by repository engineering to design the underground facility and to develop a repository layout adapted to the site. It also provides input to the safety assessment. Another important use of the hydrogeological model is in the environmental impact assessment. This report presents the understanding of the hydrogeological conditions of the bedrock at Forsmark reached following the completion of the surface-based investigations and provides a summary of the bedrock hydrogeological model and the underlying data supporting its development. It constitutes the main reference on bedrock hydrogeology for the site descriptive model concluding the surface-based investigations at Forsmark, SDM-site, and is intended to describe the hydraulic properties and hydrogeological conditions of the bedrock at the site and to give the information essential for demonstrating understanding

  18. Bedrock Geologic Map of Vermont - Faults and Contacts

    Data.gov (United States)

    Vermont Center for Geographic Information — The bedrock geology was last mapped at a statewide scale 50 years ago at a scale of 1:250,000 (Doll and others, 1961). The 1961 map was compiled from 1:62,500-scale...

  19. The amount of glacial erosion of the bedrock

    International Nuclear Information System (INIS)

    Paasse, Tore

    2004-11-01

    The purpose of this study is to estimate an upper bound for the average erosion of fresh bedrock that can reasonably be expected during a glacial period or a single glaciation. The study is based on the assumption that classic sediments, formed by Scandinavian ice erosion during the Quaternary period, still exist within the formerly glaciated area or its periphery. The volume of these sediments thus constitutes the maximum average glacial erosion of bedrock within this area. This volume is calculated by estimating the thickness of the minerogenic Quaternary from well data in Sweden and Denmark and from seismic measurements in adjacent sea areas. The average thickness of the Quaternary deposits and other reogolith in the investigated area was estimated to 16 m. Assuming that the whole volume is the result of glacial erosion of fresh bedrock this corresponds to 12 m depth. However, a great part of the sediments may consist of glacially redistributed Tertiary regolith. As the amount of Tertiary regolith is uncertain the estimated maximum average glacial erosion rate in fresh bedrock is uncertain, and assuming that the total sediment volume is the result of glacial erosion leads to an overestimation of the glacial erosion depth. Considering this, the average glacial erosion during a full glacial period has been estimated to between 0.2 m and 4 m. If the extremes in the made assumptions are excluded the glacial erosion during a glacial cycle can be estimated to about 1 m

  20. The amount of glacial erosion of the bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Paasse, Tore [Geological Survey of Sweden, Uppsala (Sweden)

    2004-11-01

    The purpose of this study is to estimate an upper bound for the average erosion of fresh bedrock that can reasonably be expected during a glacial period or a single glaciation. The study is based on the assumption that classic sediments, formed by Scandinavian ice erosion during the Quaternary period, still exist within the formerly glaciated area or its periphery. The volume of these sediments thus constitutes the maximum average glacial erosion of bedrock within this area. This volume is calculated by estimating the thickness of the minerogenic Quaternary from well data in Sweden and Denmark and from seismic measurements in adjacent sea areas. The average thickness of the Quaternary deposits and other reogolith in the investigated area was estimated to 16 m. Assuming that the whole volume is the result of glacial erosion of fresh bedrock this corresponds to 12 m depth. However, a great part of the sediments may consist of glacially redistributed Tertiary regolith. As the amount of Tertiary regolith is uncertain the estimated maximum average glacial erosion rate in fresh bedrock is uncertain, and assuming that the total sediment volume is the result of glacial erosion leads to an overestimation of the glacial erosion depth. Considering this, the average glacial erosion during a full glacial period has been estimated to between 0.2 m and 4 m. If the extremes in the made assumptions are excluded the glacial erosion during a glacial cycle can be estimated to about 1 m.

  1. Bedrock Geologic Map of Vermont - Geochronology Sample Locations

    Data.gov (United States)

    Vermont Center for Geographic Information — The bedrock geology was last mapped at a statewide scale 50 years ago at a scale of 1:250,000 (Doll and others, 1961). The 1961 map was compiled from 1:62,500-scale...

  2. Bedrock geology Forsmark. Modelling stage 2.3. Description of the bedrock geological map at the ground surface

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, Michael B.; Bergman, Torbjoern (Geological Survey of Sweden, Uppsala (Sweden)); Isaksson, Hans (GeoVista AB, Luleaa (Sweden)); Petersson, Jesper (SwedPower AB, Stockholm (Sweden))

    2008-12-15

    A description of the bedrock geological map of the ground surface at the Forsmark site is presented here. This map is essentially a 2D model for the distribution of different types of rock unit on this surface. Besides showing the distribution of these rock units, the bedrock geological map also displays the distribution of some deformation zones that intersect the ground surface. It also presents information bearing on the position and form of outcrops, the location and projection of boreholes drilled during the site investigation programme, subordinate rock types, the occurrence of abandoned mines or exploration prospects, measurements of ductile structures in outcrops, inferred form lines, key minerals, and the occurrence of mylonite and cataclastic rock. Bedrock data from outcrops and excavations, airborne and ground magnetic data and information from the uppermost part of boreholes have all been used in the construction of the geological map. The description has also made use of complementary analytical data bearing on the composition and age of the rocks as well gamma-ray spectrometry and gravity data. Uncertainty in the position of the boundaries between rock units over the mapped area are addressed in a qualitative manner. Four model versions of the bedrock geological map have been delivered to SKB's GIS database (bedrock geological map, Forsmark, versions 1.1, 1.2, 2.2 and 2.3) at different times during the site investigation programme. The Forsmark area is situated along the coast of the Baltic Sea in northern Uppland, Sweden, in a region where the overall level of ductile strain in the bedrock is high. This high-strain region extends several tens of kilometres across the WNW-ENE to NW-SE strike of the rocks in this part of the Fennoscandian Shield. At Forsmark, the coastal region is composed partly of high-strain belts, which formed under amphibolite-facies metamorphic conditions, and partly of tectonic lenses, where the bedrock is also affected by

  3. Bedrock geology Forsmark. Modelling stage 2.3. Description of the bedrock geological map at the ground surface

    International Nuclear Information System (INIS)

    Stephens, Michael B.; Bergman, Torbjoern; Isaksson, Hans; Petersson, Jesper

    2008-12-01

    A description of the bedrock geological map of the ground surface at the Forsmark site is presented here. This map is essentially a 2D model for the distribution of different types of rock unit on this surface. Besides showing the distribution of these rock units, the bedrock geological map also displays the distribution of some deformation zones that intersect the ground surface. It also presents information bearing on the position and form of outcrops, the location and projection of boreholes drilled during the site investigation programme, subordinate rock types, the occurrence of abandoned mines or exploration prospects, measurements of ductile structures in outcrops, inferred form lines, key minerals, and the occurrence of mylonite and cataclastic rock. Bedrock data from outcrops and excavations, airborne and ground magnetic data and information from the uppermost part of boreholes have all been used in the construction of the geological map. The description has also made use of complementary analytical data bearing on the composition and age of the rocks as well gamma-ray spectrometry and gravity data. Uncertainty in the position of the boundaries between rock units over the mapped area are addressed in a qualitative manner. Four model versions of the bedrock geological map have been delivered to SKB's GIS database (bedrock geological map, Forsmark, versions 1.1, 1.2, 2.2 and 2.3) at different times during the site investigation programme. The Forsmark area is situated along the coast of the Baltic Sea in northern Uppland, Sweden, in a region where the overall level of ductile strain in the bedrock is high. This high-strain region extends several tens of kilometres across the WNW-ENE to NW-SE strike of the rocks in this part of the Fennoscandian Shield. At Forsmark, the coastal region is composed partly of high-strain belts, which formed under amphibolite-facies metamorphic conditions, and partly of tectonic lenses, where the bedrock is also affected by

  4. The role of bedrock groundwater in rainfall-runoff response at hillslope and catchment scales

    Science.gov (United States)

    Gabrielli, C. P.; McDonnell, J. J.; Jarvis, W. T.

    2012-07-01

    SummaryBedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Direct hydrometric measurements have been limited due to the logistical challenges associated with drilling through hard rock in steep, remote and often roadless terrain. We used a new portable bedrock drilling system to explore bedrock groundwater dynamics aimed at quantifying bedrock groundwater contributions to hillslope flow and catchment runoff. We present results from the Maimai M8 research catchment in New Zealand and Watershed 10 (WS10) at the H.J. Andrews Experimental Forest in Oregon, USA. Analysis of bedrock groundwater at Maimai, through a range of flow conditions, revealed that the bedrock water table remained below the soil-bedrock interface, indicating that the bedrock aquifer has minimal direct contributions to event-based hillslope runoff. However, the bedrock water table did respond significantly to storm events indicating that there is a direct connection between hillslope processes and the underlying bedrock aquifer. WS10 groundwater dynamics were dominated by fracture flow. A highly fractured and transmissive zone within the upper one meter of bedrock conducted rapid lateral subsurface stormflow and lateral discharge. The interaction of subsurface stormflow with bedrock storage directly influenced the measured hillslope response, solute transport and computed mean residence time. This research reveals bedrock groundwater to be an extremely dynamic component of the hillslope hydrological system and our comparative analysis illustrates the potential range of hydrological and geological controls on runoff generation in headwater catchments.

  5. Periglacial disruption and subsequent glacitectonic deformation of bedrock : an example from Anglesey, North Wales, UK

    OpenAIRE

    Phillips, Emrys; Lee, Jonathan R.; Riding, James B.; Kendall, Rhian; Hughes, Leanne

    2012-01-01

    The deformed metasedimentary bedrock and overlying diamictons in western Anglesey, NW Wales, record evidence of glacier-permafrost interactions during the Late Devensian (Weichselian). The locally highly brecciated New Harbour Group bedrock is directly overlain by a bedrock-rich diamicton which preserves evidence of having undergone both periglacial (brecciation, hydrofracturing) and glacitectonic deformation (thrusting, folding), and is therefore interpreted as periglacial head d...

  6. Rapid Assessment of Remedial Effectiveness and Rebound in Fractured Bedrock

    Science.gov (United States)

    2017-10-01

    Geologic Cross Section of the CPP Demonstration Area................. 27 Figure 5.4. Increases in Bromide Concentration in the Deep Interval of MW07-46R...NPV Net Present Value O&M Operation and Maintenance OU Operable Unit PCE Tetrachloroethene PFM passive flux meter PPE Personal protective...miles wide, and up to 12,000 ft deep . The bedrock unit underlying the site is the Pennsylvanian age Rhode Island Formation, which consists of

  7. Trench infiltration for managed aquifer recharge to permeable bedrock

    Science.gov (United States)

    Heilweil, V.M.; Watt, D.E.

    2011-01-01

    Managed aquifer recharge to permeable bedrock is increasingly being utilized to enhance resources and maintain sustainable groundwater development practices. One such target is the Navajo Sandstone, an extensive regional aquifer located throughout the Colorado Plateau of the western United States. Spreading-basin and bank-filtration projects along the sandstone outcrop's western edge in southwestern Utah have recently been implemented to meet growth-related water demands. This paper reports on a new cost-effective surface-infiltration technique utilizing trenches for enhancing managed aquifer recharge to permeable bedrock. A 48-day infiltration trench experiment on outcropping Navajo Sandstone was conducted to evaluate this alternative surface-spreading artificial recharge method. Final infiltration rates through the bottom of the trench were about 0.5 m/day. These infiltration rates were an order of magnitude higher than rates from a previous surface-spreading experiment at the same site. The higher rates were likely caused by a combination of factors including the removal of lower permeability soil and surficial caliche deposits, access to open vertical sandstone fractures, a reduction in physical clogging associated with silt and biofilm layers, minimizing viscosity effects by maintaining isothermal conditions, minimizing chemical clogging caused by carbonate mineral precipitation associated with algal photosynthesis, and diminished gas clogging associated with trapped air and biogenic gases. This pilot study illustrates the viability of trench infiltration for enhancing surface spreading of managed aquifer recharge to permeable bedrock. ?? 2010.

  8. Bedrock erosion by sliding wear in channelized granular flow

    Science.gov (United States)

    Hung, C. Y.; Stark, C. P.; Capart, H.; Smith, B.; Maia, H. T.; Li, L.; Reitz, M. D.

    2014-12-01

    Boundary forces generated by debris flows can be powerful enough to erode bedrock and cause considerable damage to infrastructure during runout. Bedrock wear can be separated into impact and sliding wear processes. Here we focus on sliding wear. We have conducted experiments with a 40-cm-diameter grainflow-generating rotating drum designed to simulate dry channelized debris flows. To generate sliding erosion, we placed a 20-cm-diameter bedrock plate axially on the back wall of the drum. The rotating drum was half filled with 2.3-mm-diameter grains, which formed a thin grain-avalanching layer with peak flow speed and depth close to the drum axis. The whole experimental apparatus was placed on a 100g-ton geotechnical centrifuge and, in order to scale up the stress level, spun to a range of effective gravity levels. Rates and patterns of erosion of the bedrock plate were mapped after each experiment using 3d micro-photogrammetry. High-speed video and particle tracking were employed to measure granular flow dynamics. The resulting data for granular velocities and flow geometry were used to estimate impulse exchanges and forces on the bedrock plate. To address some of the complexities of granular flow under variable gravity levels, we developed a continuum model framed around a GDR MiDi rheology. This model allowed us to scale up boundary forcing while maintaining the same granular flow regime, and helped us to understand important aspects of the flow dynamics including e.g. fluxes of momentum and kinetic energy. In order to understand the detailed processes of boundary forcing, we performed numerical simulations with a new contact dynamics model. This model confirmed key aspects of our continuum model and provided information on second-order behavior such as fluctuations in the forces acting on the wall. By combining these measurements and theoretical analyses, we have developed and calibrated a constitutive model for sliding wear that is a threshold function of

  9. Fractured Bedrock Storm Flow: a New Pathway for Runoff Generation

    Science.gov (United States)

    Oshun, J.; Salve, R.; Rempe, D. M.; Dietrich, W. E.; Fung, I.

    2010-12-01

    Groundwater dynamics in the fractured weathered bedrock underlying hillslopes may dominate storm runoff in many hilly and mountainous areas Few studies, however, have explored this runoff generation process. Here we use an intensively monitored site to study the spatial relationships between fractured bedrock and hydraulic properties in the weathered zone below a forested hillslope. The study site, Rivendell, is a 4000 m2 catchment draining directly into Elder Creek in the Angelo Coast Range Reserve (ACRR) in Northern California. The site is underlain by highly fractured and weak mudstones and boudinaged, ridge-forming sandstones that are turbidite sequences of the Coastal Franciscan Belt. The site receives an average of 1800mm of precipitation annually, with the vast majority falling between October and May. Rivendell has a thinly mantled soil layer underlain by a fractured rock zone, which thickens upslope to a depth of up to 30 m. Standard penetration tests show a consistent increase in bedrock resistance at depth before an abrupt lower boundary upon which the water table is perched. We use seven monitoring wells, precipitation data, soil moisture data, a steam gauge in Elder Creek, and well pump tests to characterize water movement through the fractured rock zone.. We analyze the lag time between peak rainfall and peak response at seven wells and Elder Creek from 2007-2010. The water table varies across the slope between 4 and 25 m below the ground surface, and the dynamic range of well water level increases with distance from Elder Creek. The magnitude and timing of well response shows a relationship to depth, magnitude of rainfall and antecedent moisture conditions. Although nearly all runoff is generated through fractured bedrock, we observe that Elder Creek consistently shows the shortest lag times compared to the wells on the hillslope. Wells show different trends in magnitude and timing of response throughout the rainy season. Pump tests reveal a

  10. Long-term bedrock behavior research for soft rock

    International Nuclear Information System (INIS)

    Inoue, Hiroyuki; Noda, Kenji

    2002-02-01

    When a formation disposal system is thought about, it is important to evaluate long-term dynamics behavior of boundary condition and near field bedrock of an artificial barrier adequately. In this study, three matters were executed for improvement of a dependability of the evaluation as follows. (1) Creep test was executed as purpose by dependability improvement of evaluation technique of creep problem by Okubo model. Okubo model constant was calculated than the unconfined compression test which let strain rate change with true rock, and the creep test which the constant was used, and estimated breaking time was done. As a result, the estimation of breaking time by Okubo model almost suffered according to the estimation although a variation of test-piece influenced it. (2) A tunnel model apparatus was produced in the purpose which grasped near field bedrock behavior, and it was tested. Simulation rock test body of 1 m * 1 m * 0.5 m was used for a test, and 15 cm tunnel excavation was carried out in an initial stress bottom. Quantities of inner space displacement were measured in a test, and a hardness-test was done after dismantlement, and looseness area was grasped quantitatively. As a result, the looseness area was able to be estimated with about 17.5 cm than tunnel center position. (3) A test approach in deep underground laboratory was examined, and examination/the in situ test which took advantage of rock core analysis/borehole as purpose and done examination item by grip of long-term bedrock behavior (a bord is taken advantage of, and bord itself is used) was shown. In addition, layout of the deep underground laboratory which carried out various tests about long-term behavior in 3 depth was shown. (author)

  11. Effects of Bedrock Landsliding on Cosmogenically Determined Erosion Rates

    Science.gov (United States)

    Niemi, Nathan; Oskin, Mike; Burbank, Douglas; Heimsath, Arjun

    2005-01-01

    The successful quantification of long-term erosion rates underpins our understanding of landscape. formation, the topographic evolution of mountain ranges, and the mass balance within active orogens. The measurement of in situ-produced cosmogenic radionuclides (CRNs) in fluvial and alluvial sediments is perhaps the method with the greatest ability to provide such long-term erosion rates. In active orogens, however, deep-seated bedrock landsliding is an important erosional process, the effect of which on CRN-derived erosion rates is largely unquantified. We present a numerical simulation of cosmogenic nuclide production and distribution in landslide-dominated catchments to address the effect of bedrock landsliding on cosmogenic erosion rates in actively eroding landscapes. Results of the simulation indicate that the temporal stability of erosion rates determined from CRN concentrations in sediment decreases with increased ratios of landsliding to sediment detachment rates within a given catchment area, and that larger catchment areas must be sampled with increased frequency of landsliding in order to accurately evaluate long-term erosion rates. In addition, results of this simulation suggest that sediment sampling for CRNs is the appropriate method for determining long-term erosion rates in regions dominated by mass-wasting processes, while bedrock surface sampling for CRNs is generally an ineffective means of determining long-term erosion rates. Response times of CRN concentrations to changes in erosion rate indicate that climatically driven cycles of erosion may be detected relatively quickly after such changes occur, but that complete equilibration of CRN concentrations to new erosional conditions may take tens of thousands of years. Simulation results of CRN erosion rates are compared with a new, rich dataset of CRN concentrations from the Nepalese Himalaya, supporting conclusions drawn from the simulation.

  12. The bedrock and the soil types in the Finnsjoearea, Sweden

    International Nuclear Information System (INIS)

    Almen, K.-E.; Ekman, L.; Olkiewicz, A.

    1978-11-01

    This report is a part of a long-term project, started at the request of the Nuclear Fuel Safety Project, Sweden. The aim of the project is to claryfy the geohydrological situation of a drainage area close to Finnsjoen in northern Uppland, Sweden. The work comprised bedrock- and soil mapping as well as an investigation of existing literature about the geology of northern Uppland. The area is about 25 km 2 and is limited by its water-shed. The area is relatively flat, rich in outcrops - expecially in the western parts - and often swampy. Big areas of forests and agriculture have been drained by ditches. (author)

  13. Arsenic evolution in fractured bedrock wells in central Maine, USA

    Science.gov (United States)

    Yang, Q.; Zheng, Y.; Culbertson, C.; Schalk, C.; Nielsen, M. G.; Marvinney, R.

    2010-12-01

    Elevated arsenic concentration in fractured bedrock wells has emerged as an important and challenging health problem, especially in rural areas without public water supply and mandatory monitoring of private wells. This has posed risks of skin, bladder, prostate diseases and cancers to private well users. In central Maine, including the study site, 31% of bedrock wells in meta-sedimentary formations have been reported of elevated arsenic concentrations of > 10 µg/L. Geophysical logging and fracture specific water sampling in high arsenic wells have been conducted to understand how water flowing through the aquifers enters the boreholes and how arsenic evolves in the fracture bedrock wells. Two domestic wells in Manchester, Maine, located 50 meter apart with 38 µg/L and 73 µg/L of arsenic in unfiltered water, were investigated to characterize fractures by geophysical logging and to determine flow rates by pumping test. Water samples, representing the bore hole and the fractures, were collected and analyzed for arsenic under ambient and pumping conditions. Transmissivity of the fractures was estimated at 0.23-10.6 m2/day. Water with high dissolved arsenic was supplied primarily by high yielding fractures near the bottom of the borehole. Dissolved arsenic concentrations in borehole water increased as fracture water with high arsenic was replacing borehole water with initially low dissolved arsenic in response to pumping. The precipitation of iron particulates enriched in arsenic was common during and after pumping. Laboratory experiment on well water samples over a period of 16 days suggested that in the borehole arsenic was mainly settled with iron enriched particles, likely amorphous ferric oxyhydroxides, with possibly minor adsorption on the iron minerals. Another bedrock well in Litchfield, Maine, with 478 µg/L of arsenic in the unfiltered well water, is being investigated to quantify and reconstruct of the groundwater flow under ambient and pumping conditions

  14. Sorption processes of radiocesium in soil and bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Lehto, Jukka [Helsinki Univ. (Finland). Lab. of Radiochemistry

    2015-06-01

    Three recent studies on cesium sorption in soil and bedrock are reviewed. {sup 137}Cs, originating from fallouts of nuclear weapons tests and the Chernobyl accident was found to decrease in an exponential manner in forest soil, and the highest fraction in soil profiles was found in the organic layer. Also, the mineral layer below the organic layer contained a large fraction of cesium inventory but at depths below 20 cm only a very small fraction was observed. In the bedrock of Olkiluoto, where the final repository for spent nuclear fuel from the Finnish nuclear power plants will be constructed, mica mineral biotite plays the most important role in cesium sorption. The selectivity of biotite decreases in the order Cs > K > Na > Ca and the overall selectivity coefficient for Cs/Ca exchange was approximately five and seven orders of magnitude higher than those for Cs/Na and Cs/K exchange reactions, respectively. Ion exchange isotherms for Cs/Na and Cs/K exchange were modelled by assuming three different ion exchange sites: frayed edge sites (FES), basal plane sites and intermediate sites. The selectivity coefficients derived for these sites were successfully used to predict cesium sorption in a mica gneiss rock. Sorption of cesium in mineral soil layers from the Olkiluoto overburden were studied using three different approaches: model batch experiments, an in-situ method and calculations. All three approaches gave the same trend but the distribution coefficient values varied in range of one order of magnitude.

  15. Bedrock neutralization study for the Bruin Lagoon Superfund Site

    International Nuclear Information System (INIS)

    Patelunas, G.M.; Lenhardt, D.R.; Niece, J.E.

    1989-01-01

    The Bruin Lagoon site is located in Bruin Butler County, Pennsylvania, and is listed as No. 3 on the U.S. Environmental Protection Agencies' National Priority List. The Lagoon contains waste petroleum tars, sulfuric acid, coal combustion ash, spent bauxite and other waste materials. This paper reports on the bedrock neutralization study, conducted to assess the feasibility of injecting caustic solutions into acid-contaminated bedrock beneath the lagoon. The site is underlain by a fine to medium grain quartz sandstone which is contaminated with acid to depths in excess of 30 feet. For this investigation, Nx-cores were obtained and pressure tests conducted to a depth of 30 feet below the top of rock. Leach tests were conducted on contaminated core sections using sodium hydroxide and sodium carbonate solutions. A total of 12 core sections were exposed in 3-inch diameter test cylinders and permeated under a positive pressure of 25 to 50 psi. Measurements of leachate volume, temperature, pH, and hydraulic conductivity were recorded

  16. Final disposal of spent nuclear fuel in the Finnish bedrock

    International Nuclear Information System (INIS)

    1992-12-01

    Teollisuuden Voima Oy (TVO) studies Finnish bedrock for the final disposal of the spent nuclear fuel from the Olkiluoto nuclear power plant. The study is in accordance with the decision in principle by Finnish government in 1983. The report is the summary of the preliminary site investigations carried out during the years 1987-1992. On the basis of these investigations a few areas will be selected for detailed site investigation. The characterization comprises five areas selected from the shortlist of potential candidate areas resulted in the earlier study during 1983-1985. Areas are located in different parts of Finland and they represent the main formations of the Finnish bedrock. Romuvaara area in Kuhmo and Veitsivaara area in Hyrynsalmi represent the Archean basement. Kivetty area in Konginkangas consists of mainly younger granitic rocks. Syyry in Sievi is located in transition area of Svecofennidic rocks and granitic rocks. Olkiluoto in Eurajoki represents migmatites in southern Finland. For the field investigations area-specific programs were planned and executed. The field investigations have comprised airborne survey by helicopter, geophysical surveys, geological mappings and samplings, deep and shallow core drillings, geophysical and hydrological borehole measurements and groundwater samplings

  17. Constraining local subglacial bedrock erosion rates with cosmogenic nuclides

    Science.gov (United States)

    Wirsig, Christian; Ivy-Ochs, Susan; Christl, Marcus; Reitner, Jürgen; Reindl, Martin; Bichler, Mathias; Vockenhuber, Christof; Akcar, Naki; Schlüchter, Christian

    2014-05-01

    The constant buildup of cosmogenic nuclides, most prominently 10Be, in exposed rock surfaces is routinely employed for dating various landforms such as landslides or glacial moraines. One fundamental assumption is that no cosmogenic nuclides were initially present in the rock, before the event to be dated. In the context of glacially formed landscapes it is commonly assumed that subglacial erosion of at least a few meters of bedrock during the period of ice coverage is sufficient to remove any previously accumulated nuclides, since the production of 10Be ceases at a depth of 2-3 m. Insufficient subglacial erosion leads to overestimation of surface exposure ages. If the time since the retreat of the glacier is known, however, a discordant concentration of cosmogenic nuclides delivers information about the depth of subglacial erosion. Here we present data from proglacial bedrock at two sites in the Alps. Goldbergkees in the Hohe Tauern National Park in Austria and Gruebengletscher in the Grimsel Pass area in Switzerland. Samples were taken inside as well as outside of the glaciers' Little Ice Age extent. Measured nuclide concentrations are analyzed with the help of a MATLAB model simulating periods of exposure or glacial cover of user-definable length and erosion rates.

  18. Calculating the spatio-temporal variability of bedrock exposure on seasonal hydrograph timescales as a prerequisite to modeling bedrock river evolution

    Science.gov (United States)

    Hurst, A. A.; Anderson, R. S.; Tucker, G. E.

    2017-12-01

    Erosion of bedrock river channels exerts significant control on landscape evolution because it communicates climatic and tectonic signals across a landscape by setting the lower erosional boundaries for hillslopes. Hillslope erosion delivers sediment to the channels, which then either store or transport the sediment. At times of high storage, access to the bedrock floor of the channel is limited, inhibiting bedrock erosion. This affects the timescale of channel response to imposed base-level lowering, which in turn affects hillslope erosion. Because occasional exposure of the bedrock bed is a minimum prerequisite for bedrock erosion, we seek to understand the evolution of sediment cover, or scour history, with sufficient resolution to answer when and where the bed is exposed. The scour history at a site is governed by grain size, bed and channel morphology, sediment concentration in the water, and seasonal flow conditions (hydrograph). The transient nature of bedrock exposure during high-flow events implies that short-term sediment cover dynamics are important for predicting long-term bedrock incision rates. Models of channel profile evolution, or of landscape evolution, generally ignore evolution of sediment cover on the hydrograph timescale. To develop insight into the necessary and sufficient conditions for bedrock exposure followed by reburial, we have developed a 1-D model of the evolution of alluvial cover thickness in a long channel profile in response to a seasonal hydrograph. This model tracks erosion, deposition, and the concentration of sediment in the water column separately, and generates histories of scour and fill over the course of the hydrograph. We compare the model's predictions with net-scour measurements in tributaries of the Grand Canyon and with scour-chain and accelerometer measurements in the Cedar River, Washington. By addressing alluvial scour on short timescales, we acknowledge the processes required to allow bedrock incision and

  19. 3D Bedrock Structure of Bornova Plain and Its surroundings (İzmir/Western Turkey)

    Science.gov (United States)

    Pamuk, Eren; Gönenç, Tolga; Özdağ, Özkan Cevdet; Akgün, Mustafa

    2018-01-01

    An earthquake record is needed on engineering bedrock to perform soil deformation analysis. This record could be obtained in different ways (seismographs on engineering bedrock; by the help of the soil transfer function; scenario earthquakes). S-wave velocity ( V s) profile must be known at least till engineering bedrock for calculating soil transfer functions true and completely. In addition, 2D or 3D soil, engineering-seismic bedrock models are needed for soil response analyses to be carried out. These models are used to determine changes in the amplitude and frequency content of earthquake waves depending on the seismic impedance from seismic bedrock to the ground surface and the basin effects. In this context, it is important to use multiple in situ geophysical techniques to create the soil-bedrock models. In this study, 2D and 3D soil-bedrock models of Bornova plain and its surroundings (Western Turkey), which are very risky in terms of seismicity, were obtained by combined survey of surface wave and microgravity methods. Results of the study show that the engineering bedrock depths in the middle part of Bornova plain range from 200 to 400 m and the southern and northern parts which are covered limestone and andesite show the engineering bedrock ( V s > 760 m/s) feature. In addition, seismic bedrock ( V s < 3000 m/s) depth changes from 550 to 1350 m. The predominant period values obtained from single station microtremor method change from 0.45 to 1.6 s while they are higher than 1 s in the middle part of Bornova plain where the basin is deeper. Bornova Plain has a very thick sediment units which have very low V s values above engineering bedrock. In addition, it is observed sudden changes at the interfaces of the layer in horizontal and vertical directions.

  20. Bedrock hydrogeochemistry Forsmark. Site descriptive modelling SDM-Site Forsmark

    International Nuclear Information System (INIS)

    Laaksoharju, Marcus; Smellie, John; Tullborg, Eva-Lena; Gimeno, Maria; Hallbeck, Lotta; Molinero, Jorge; Waber, Nick

    2008-12-01

    The overall objectives of the hydrogeochemical site description for Forsmark are to establish a detailed understanding of the hydrogeochemical conditions at the site, and to use this understanding to develop models that address the needs identified by the safety assessment groups during the site investigation phase. Issues of concern to safety assessment are radionuclide transport and technical barrier behaviour, both of which are dependent on the chemistry of groundwater and porewater and their evolution with time. The specific aims of the hydrogeochemical work were: To document the hydrogeochemistry at the Forsmark site with focus on the development of conceptual models to describe and visualise the site. To provide relevant parameter values to be used for safety assessment calculations. To provide the hydrogeochemical basis for the modelling work by other teams, in particular hydrogeology. To take account of the feedback from the SR-Can safety assessment work that bears relevance to the hydrogeochemical modelling work. The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. In this report, the groundwaters have been interpreted in relation to their origin, evolution and composition, which require close integration with geological, climatological and hydrogeological information. Past climate changes are one of the major driving forces for long-term hydrogeochemical changes (hundreds to thousands of years) and are, therefore, of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the Fennoscandian crystalline bedrock. In contrast, redox buffer capacity of the bedrock will minimise the effects on changes in alkalinity and redox at repository depths, therefore limiting the variations in pH and Eh significantly, regardless of major changes in groundwater composition. There is

  1. Bedrock hydrogeochemistry Forsmark. Site descriptive modelling SDM-Site Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Laaksoharju, Marcus (Geopoint AB, Sollentuna (Sweden)); Smellie, John (Conterra AB, Partille (Sweden)); Tullborg, Eva-Lena (Terralogica, Graabo (Sweden)); Gimeno, Maria (Univ. of Zaragoza, Zaragoza (Spain)); Hallbeck, Lotta (Microbial Analytics, Goeteborg (Sweden)); Molinero, Jorge (Amphos XXI Consulting S.L., Barcelona (Spain)); Waber, Nick (Univ. of Bern, Bern (Switzerland))

    2008-12-15

    The overall objectives of the hydrogeochemical site description for Forsmark are to establish a detailed understanding of the hydrogeochemical conditions at the site, and to use this understanding to develop models that address the needs identified by the safety assessment groups during the site investigation phase. Issues of concern to safety assessment are radionuclide transport and technical barrier behaviour, both of which are dependent on the chemistry of groundwater and porewater and their evolution with time. The specific aims of the hydrogeochemical work were: To document the hydrogeochemistry at the Forsmark site with focus on the development of conceptual models to describe and visualise the site. To provide relevant parameter values to be used for safety assessment calculations. To provide the hydrogeochemical basis for the modelling work by other teams, in particular hydrogeology. To take account of the feedback from the SR-Can safety assessment work that bears relevance to the hydrogeochemical modelling work. The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. In this report, the groundwaters have been interpreted in relation to their origin, evolution and composition, which require close integration with geological, climatological and hydrogeological information. Past climate changes are one of the major driving forces for long-term hydrogeochemical changes (hundreds to thousands of years) and are, therefore, of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the Fennoscandian crystalline bedrock. In contrast, redox buffer capacity of the bedrock will minimise the effects on changes in alkalinity and redox at repository depths, therefore limiting the variations in pH and Eh significantly, regardless of major changes in groundwater composition. There is

  2. Amplified Erosion above Waterfalls and Oversteepened Bedrock Reaches

    Science.gov (United States)

    Haviv, I.; Enzel, Y.; Whipple, K. X.; Zilberman, E.; Stone, J.; Matmon, A.; Fifield, K. L.

    2005-12-01

    Although waterfalls are abundant along steep bedrock channels, none of the conventional erosion laws can predict incision at the lip of a waterfall where flow is non-uniform and bed slope can be vertical. Considering the expected increase in flow velocity and shear stress at the lip of a vertical waterfall we determine erosion amplification at a waterfall lip as: Elip/Enormal= (1+0.4/Fr2)3n, where Fr is the Froude number and n ranges between 0.5-1.7. This amplification expression suggests that erosion at the lip could be as much as 2-5 times higher than normally expected in a setting with identical hydraulic geometry. It also demonstrates that a freefall is expected to amplify upstream incision rates even when the flow approaching the waterfall is highly supercritical. Utilizing this erosion amplification expression in numerical simulations in conjunction with a standard detachment-limited incision model we demonstrate its impact on reach-scale morphology above waterfalls. These simulations indicate that amplified erosion at the lip of a waterfall can trigger the formation of an oversteepened reach whose length is longer than the flow acceleration zone, provided incision velocity (Vi) at the edge of the flow acceleration zone is higher than the retreat velocity of the waterfall face. Such an oversteepened reach is expected to be more pronounced when Vi increases with increasing slope. The simulations also suggest that oversteepening can eventually lead to quasi steady-state gradients upstream from a waterfall provided Vi decreases with increasing slope. Flow acceleration above waterfalls can thus account, at least partially, for oversteepened bedrock reaches that are prevalent above waterfalls. Such reaches have been reported for the escarpments of southeast Australia, western Dead Sea, and at Niagara Falls. Using the cosmogenic isotope 36Cl we demonstrate that Vi upstream of a waterfall at the Dead Sea western escarpment is high enough for freefall

  3. Ice sheet growth with laterally varying bedrock relaxation time

    Science.gov (United States)

    van der Wal, Wouter; Vizcaino Rubio, Pablo; De Boer, Bas; van de Wal, Roderik

    2017-04-01

    Isostatic response of the bedrock, or glacial isostatic adjustment (GIA) in included in most ice sheet models. This is important because the surface elevation determines the mass balance and thereby implicitly also the strength of the mass balance feedback where higher surface elevation yields lower temperatures implying less melt and vice versa. Usually a single relaxation time or a set of relaxation times is used to model the response everywhere on Earth or at least for an entire ice sheet. In reality the viscosity in the Earth's mantle, and hence the relaxation time experienced by the ice, varies with location. Seismic studies indicate that several regions that were covered by ice during the last glacial cycle are underlain by mantle in which viscosity varies with orders of magnitude, such as Antarctica and North America. The question is whether such a variation of viscosity influences ice evolution. Several GIA models exist that can deal with 3D viscosity, but their large computation times make it nearly impossible to couple them to ice sheet models. Here we use the ANICE ice-sheet model (de Boer et al. 2013) with a simple bedrock-relaxation model in which a different relaxation time is used for separate regions. A temperature anomaly is applied to grow a schematic ice sheet on a flat earth, with other forcing mechanisms neglected. It is shown that in locations with a fast relaxation time of 300 years the equilibrium ice sheet is significantly thinner and narrower but also ice thickness in neighbouring regions (with the more standard relaxation time of 3000 years) is affected.

  4. Shallow bedrock limits groundwater seepage-based headwater climate refugia

    Science.gov (United States)

    Briggs, Martin A.; Lane, John W.; Snyder, Craig D.; White, Eric A.; Johnson, Zachary; Nelms, David L.; Hitt, Nathaniel P.

    2018-01-01

    Groundwater/surface-water exchanges in streams are inexorably linked to adjacent aquifer dynamics. As surface-water temperatures continue to increase with climate warming, refugia created by groundwater connectivity is expected to enable cold water fish species to survive. The shallow alluvial aquifers that source groundwater seepage to headwater streams, however, may also be sensitive to seasonal and long-term air temperature dynamics. Depth to bedrock can directly influence shallow aquifer flow and thermal sensitivity, but is typically ill-defined along the stream corridor in steep mountain catchments. We employ rapid, cost-effective passive seismic measurements to evaluate the variable thickness of the shallow colluvial and alluvial aquifer sediments along a headwater stream supporting cold water-dependent brook trout (Salvelinus fontinalis) in Shenandoah National Park, VA, USA. Using a mean depth to bedrock of 2.6 m, numerical models predicted strong sensitivity of shallow aquifer temperature to the downward propagation of surface heat. The annual temperature dynamics (annual signal amplitude attenuation and phase shift) of potential seepage sourced from the shallow modeled aquifer were compared to several years of paired observed stream and air temperature records. Annual stream water temperature patterns were found to lag local air temperature by ∼8–19 d along the stream corridor, indicating that thermal exchange between the stream and shallow groundwater is spatially variable. Locations with greater annual signal phase lag were also associated with locally increased amplitude attenuation, further suggestion of year-round buffering of channel water temperature by groundwater seepage. Numerical models of shallow groundwater temperature that incorporate regional expected climate warming trends indicate that the summer cooling capacity of this groundwater seepage will be reduced over time, and lower-elevation stream sections may no longer serve as larger

  5. The hillslope-storage Boussinesq model for non-constant bedrock slope

    NARCIS (Netherlands)

    Hilberts, A.G.J.; Loon, van E.E.; Troch, P.A.A.; Paniconi, C.

    2004-01-01

    In this study the recently introduced hill slope-storage Boussinesq (hsB) model is cast in a generalized formulation enabling the model to handle non-constant bedrock slopes (i.e. bedrock profile curvature). This generalization extends the analysis of hydrological behavior to hillslopes of arbitrary

  6. Root distribution and seasonal water status in weathered granitic bedrock under chaparral

    Science.gov (United States)

    P. D. Sternberg; M. A. Anderson; R. C. Graham; J. L. Beyers; K. R. Tice

    1996-01-01

    Soils in mountainous terrain are often thin and unable to store sufficient water to support existing vegetation through dry seasons. This observation has led to speculation about the role of bedrock in supporting plant growth in natural ecosystems, since weathered bedrocks often have appreciable porosity and, like soil, can store and transmit water. This study, within...

  7. Estimated probability of arsenic in groundwater from bedrock aquifers in New Hampshire, 2011

    Science.gov (United States)

    Ayotte, Joseph D.; Cahillane, Matthew; Hayes, Laura; Robinson, Keith W.

    2012-01-01

    Probabilities of arsenic occurrence in groundwater from bedrock aquifers at concentrations of 1, 5, and 10 micrograms per liter (µg/L) were estimated during 2011 using multivariate logistic regression. These estimates were developed for use by the New Hampshire Environmental Public Health Tracking Program. About 39 percent of New Hampshire bedrock groundwater was identified as having at least a 50 percent chance of containing an arsenic concentration greater than or equal to 1 µg/L. This compares to about 7 percent of New Hampshire bedrock groundwater having at least a 50 percent chance of containing an arsenic concentration equaling or exceeding 5 µg/L and about 5 percent of the State having at least a 50 percent chance for its bedrock groundwater to contain concentrations at or above 10 µg/L. The southeastern counties of Merrimack, Strafford, Hillsborough, and Rockingham have the greatest potential for having arsenic concentrations above 5 and 10 µg/L in bedrock groundwater.

  8. Alluvial cover controlling the width, slope and sinuosity of bedrock channels

    Science.gov (United States)

    Turowski, Jens Martin

    2018-02-01

    Bedrock channel slope and width are important parameters for setting bedload transport capacity and for stream-profile inversion to obtain tectonics information. Channel width and slope development are closely related to the problem of bedrock channel sinuosity. It is therefore likely that observations on bedrock channel meandering yields insights into the development of channel width and slope. Active meandering occurs when the bedrock channel walls are eroded, which also drives channel widening. Further, for a given drop in elevation, the more sinuous a channel is, the lower is its channel bed slope in comparison to a straight channel. It can thus be expected that studies of bedrock channel meandering give insights into width and slope adjustment and vice versa. The mechanisms by which bedrock channels actively meander have been debated since the beginning of modern geomorphic research in the 19th century, but a final consensus has not been reached. It has long been argued that whether a bedrock channel meanders actively or not is determined by the availability of sediment relative to transport capacity, a notion that has also been demonstrated in laboratory experiments. Here, this idea is taken up by postulating that the rate of change of both width and sinuosity over time is dependent on bed cover only. Based on the physics of erosion by bedload impacts, a scaling argument is developed to link bedrock channel width, slope and sinuosity to sediment supply, discharge and erodibility. This simple model built on sediment-flux-driven bedrock erosion concepts yields the observed scaling relationships of channel width and slope with discharge and erosion rate. Further, it explains why sinuosity evolves to a steady-state value and predicts the observed relations between sinuosity, erodibility and storm frequency, as has been observed for meandering bedrock rivers on Pacific Arc islands.

  9. Estimated Depth to Bedrock of Iowa as a 110 meter pixel_32bit Imagine Format Raster Dataset

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This raster dataset represents the depth to bedrock from the land surface. It was derived by subtracting a bedrock surface elevation layer from the NED 30 meter...

  10. Stochastic modeling of the cover effect and bedrock erosion

    Science.gov (United States)

    Turowski, Jens M.

    2009-03-01

    Several important fluvial bedrock erosion processes are driven by the impact of bed load particles. Bed load transport rates fluctuate strongly in both nature and experiment, and stochastic models of the transport processes have been put forward to describe this behavior. In this paper I adapt a model based on a Markov chain formulation to derive probability distributions for bed load transport rate over a rock bed only partly covered by sediment. I propose a way to calculate the probability distribution of bed cover for given sediment supply using a combinatoric model and combine the two curves to calculate probability distributions for bed cover and erosion rate at constant hydraulics. In the proposed model, mean bed cover is an exponentially declining function of the number of particles in the control volume. The model describes recently published experimental data well, but at the moment it is not possible to finally discriminate between the exponential and the previously proposed linear model formulation. Distributions of erosion rate are fairly broad functions slightly skewed toward high erosion rates.

  11. Developing and exploring a theory for the lateral erosion of bedrock channels for use in landscape evolution models

    Science.gov (United States)

    Langston, Abigail L.; Tucker, Gregory E.

    2018-01-01

    Understanding how a bedrock river erodes its banks laterally is a frontier in geomorphology. Theories for the vertical incision of bedrock channels are widely implemented in the current generation of landscape evolution models. However, in general existing models do not seek to implement the lateral migration of bedrock channel walls. This is problematic, as modeling geomorphic processes such as terrace formation and hillslope-channel coupling depends on the accurate simulation of valley widening. We have developed and implemented a theory for the lateral migration of bedrock channel walls in a catchment-scale landscape evolution model. Two model formulations are presented, one representing the slow process of widening a bedrock canyon and the other representing undercutting, slumping, and rapid downstream sediment transport that occurs in softer bedrock. Model experiments were run with a range of values for bedrock erodibility and tendency towards transport- or detachment-limited behavior and varying magnitudes of sediment flux and water discharge in order to determine the role that each plays in the development of wide bedrock valleys. The results show that this simple, physics-based theory for the lateral erosion of bedrock channels produces bedrock valleys that are many times wider than the grid discretization scale. This theory for the lateral erosion of bedrock channel walls and the numerical implementation of the theory in a catchment-scale landscape evolution model is a significant first step towards understanding the factors that control the rates and spatial extent of wide bedrock valleys.

  12. USING A MOBILE RADIO ECHO SOUNDER TO MEASURE BEDROCK TOPOGRAPHY IN EAST QUEEN MAUD LAND, ANTARCTICA

    OpenAIRE

    マエノ, ヒデオ; カミヤマ, コウキチ; フルカワ, テルオ; ワタナベ, オキツグ; ナルセ, レンジ; オカモト, ケンイチ; スイツ, タケシ; ウラツカ, セイホ; Hideo, MAENO; Kokichi, KAMIYAMA; Teruo, FURUKAWA; Okitsugu, WATANABE; Renji, NARUSE; Kenichi, OKAMOTO; Takeshi, SUITZ

    1994-01-01

    As part of the Dome-Fuji Project, the topography of the bedrock over a wide area around Dome-F and along routes from Dome-F to S16 (about 1000 km distance) was surveyed by radio echo sounder with a continuous recording system. The bedrock topography was successfully measured under ice sheets thicker than 3500m, and the performance of the radio echo sounder was confirmed. The highest point of Dome-F was located in the basin like topography of the bedrock, surrounded by more elevated areas. The...

  13. Bedrock Hydrogeology-Groundwater flow modelling. Site investigation SFR

    International Nuclear Information System (INIS)

    Oehman, Johan; Follin, Sven; Oden, Magnus

    2013-05-01

    The hydrogeological model developed for the SFR extension project (PSU) consists of 40 geologically modelled deformation zones (DZ) and 8 sub-horizontal structural-hydraulic features, called SBAstructures, not defined in the geological model. However, some of the SBA-structures coincide with what is defined as unresolved possible deformation zones (Unresolved PDZ) in the geological modelling. In addition, the hydrogeological model consists of a stochastic discrete fracture network (DFN) model intended for the less fractured rock mass volumes (fracture domains) between the zones and the SBA-structures, and a stochastic fracture model intended to handle remaining Unresolved PDZs in the geological modelling not modelled as SBA-structures in the hydrogeological modelling. The four structural components of the bedrock in the hydrogeological model, i.e. DZ, SBA, Unresolved PDZ and DFN, are assigned hydraulic properties in the hydrogeological model based on the transmissivities interpreted from single-hole hydraulic tests. The main objective of the present work is to present the characteristics of the hydrogeological model with regard to the needs of the forthcoming safety assessment SR-PSU. In concrete words, simulated data are compared with measured data, i.e. hydraulic heads in boreholes and tunnel inflow to the existing repository (SFR). The calculations suggest that the available data for flow model calibration cannot be used to motivate a substantial adjustment of the initial hydraulic parameterisation (assignment of hydraulic properties) of the hydrogeological model. It is suggested that uncertainties in the hydrogeological model are studied in the safety assessment SR-PSU by means of a large number of calculation cases. These should address hydraulic heterogeneity of deterministic structures (DZ and SBA) and realisations of stochastic fractures/fracture networks (Unresolved PDZ and DFN) within the entire SFR Regional model domain

  14. Groundwater chemistry of a nuclear waste reposoitory in granite bedrock

    International Nuclear Information System (INIS)

    Rydberg, J.

    1981-09-01

    This report concerns the prediction of the maximum dissolution rate for nuclear waste stored in the ground. That information is essential in judging the safety of a nuclear waste repository. With a limited groundwater flow, the maximum dissolution rate coincides with the maximum solubility. After considering the formation and composition of deep granite bedrock groundwater, the report discusses the maximum solubility in such groundwater of canister materials, matrix materials and waste elements. The parameters considered are pH, Eh and complex formation. The use of potential-pH (Pourbaix) diagrams is stressed; several appendixes are included to help in analyzing such diagrams. It is repeatedly found that desirable basic information on solution chemistry is lacking, and an international cooperative research effort is recommended. The report particularly stresses the lack of reliable data about complex formation and hydrolysis of the actinides. The Swedish Nuclear Fuel Safety (KBS) study has been used as a reference model. Notwithstanding the lack of reliable chemical data, particularly for the actinides and some fission products, a number of essential conclusions can be drawn about the waste handling model chosen by KBS. (1) Copper seems to be highly resistant to groundwater corrosion. (2) Lead and titanium are also resistant to groundwater, but inferior to copper. (3) Iron is not a suitable canister material. (4) Alumina (Al 2 O 3 ) is not a suitable canister material if groundwater pH goes up to or above 10. Alumina is superior to copper at pH < 9, if there is a risk of the groundwater becoming oxidizing. (5) The addition of vivianite (ferrous phosphate) to the clay backfill around the waste canisters improves the corrosion resistance of the metal canisters, and reduces the solubility of many important waste elements. This report does not treat the migration of dissolved species through the rock

  15. Bedrock Hydrogeology - Groundwater flow modelling. Site investigation SFR

    Energy Technology Data Exchange (ETDEWEB)

    Oehman, Johan [Geosigma AB, Uppsala (Sweden); Follin, Sven [SF GeoLogic AB, Taeby (Sweden); Oden, Magnus [SKB, Stockholm (Sweden)

    2013-05-15

    The hydrogeological model developed for the SFR extension project (PSU) consists of 40 geologically modelled deformation zones (DZ) and 8 sub-horizontal structural-hydraulic features, called SBAstructures, not defined in the geological model. However, some of the SBA-structures coincide with what is defined as unresolved possible deformation zones (Unresolved PDZ) in the geological modelling. In addition, the hydrogeological model consists of a stochastic discrete fracture network (DFN) model intended for the less fractured rock mass volumes (fracture domains) between the zones and the SBA-structures, and a stochastic fracture model intended to handle remaining Unresolved PDZs in the geological modelling not modelled as SBA-structures in the hydrogeological modelling. The four structural components of the bedrock in the hydrogeological model, i.e. DZ, SBA, Unresolved PDZ and DFN, are assigned hydraulic properties in the hydrogeological model based on the transmissivities interpreted from single-hole hydraulic tests. The main objective of the present work is to present the characteristics of the hydrogeological model with regard to the needs of the forthcoming safety assessment SR-PSU. In concrete words, simulated data are compared with measured data, i.e. hydraulic heads in boreholes and tunnel inflow to the existing repository (SFR). The calculations suggest that the available data for flow model calibration cannot be used to motivate a substantial adjustment of the initial hydraulic parameterisation (assignment of hydraulic properties) of the hydrogeological model. It is suggested that uncertainties in the hydrogeological model are studied in the safety assessment SR-PSU by means of a large number of calculation cases. These should address hydraulic heterogeneity of deterministic structures (DZ and SBA) and realisations of stochastic fractures/fracture networks (Unresolved PDZ and DFN) within the entire SFR Regional model domain.

  16. Glacial Chemical Alteration of Mars-Like Bedrock

    Science.gov (United States)

    Rutledge, A. M.; Horgan, B. H. N.; Havig, J. R.; Rampe, E. B.; Scudder, N.; Hamilton, T.

    2017-12-01

    Mars is understood to have had a widespread and long-lived cryosphere, including glaciers and ice sheets, possibly since the Noachian. However, the contribution of glaciers to the observed alteration mineralogy of Mars is unclear. To characterize this alteration, water and rock samples were collected from glaciated volcanic bedrock of a range of compositions in the Cascade Volcanic Arc, USA: Mount Hood (silicic), Mount Adams (intermediate), North Sister (mafic), and Middle Sister (most mafic). We analyzed glacial meltwater using field meters (pH, temperature), portable spectrophotometry (dissolved silica), and ion chromatography (major ions). We analyzed proglacial rock coatings and sediments using scanning and transmission electron microscopies with energy dispersive spectroscopy (SEM, TEM, EDS), and visible/short-wave-infrared (VSWIR) and thermal-infrared (TIR) spectroscopies. Water samples are dominated by dissolved silica across a range of pH values, and dissolved silica increases significantly at more mafic sites. Rock coatings associated with glacial striations on mafic terrains include a major poorly crystalline silica component, as do proglacial sediments. This field study demonstrates that silica cycling is the dominant alteration process at glaciated volcanics, and more mafic glaciovolcanic sites have higher concentrations of dissolved silica compared to more felsic glaciovolcanic sites. Though basalts have lower silica content than more felsic volcanic rocks, they are more susceptible to silica mobility. On Mars, widespread poorly crystalline, high silica deposits have been modeled in Nothern Acidalia and Gusev Crater, and hydrated silica deposits have been identified in Nili Fossae and elsewhere. We hypothesize that these phases may be indicators of a cold climate regime on early Mars such as one dominated by large regional ice sheets. Cryosphere-driven silica cycling on low-carbonate, mafic rocks may be more important than previously thought on Mars.

  17. Physical modeling of glacier contact with bedrock (experiment

    Directory of Open Access Journals (Sweden)

    V. P. Epifanov

    2013-01-01

    Full Text Available Studies of the adhesive strength of glacial ice connection with bedrock has been studied using the analysis of the amplitude-frequency characteristics of acoustic emission (AE in the frequency range from 15 Hz to 20,000 Hz. Identification of signal source on bed is based on physical modeling of adhesive ice fracture at the complex shear and patterns of elastic waves propagation in the ice using data on ice thickness of the ice and its acoustic properties. The experimental dependence of the ice and serpentinite substrate adhesive strength with temperature (from 0 °C to −30 °C has been obtained at constraint axial shear. It is shown that the destruction of adhesive ice contact with substrate begins long before the maximum shear stress achieved, and AE signals in the coordinates amplitude-frequency-time have been obtained for the for static friction and sliding parts of deformation curves. Influence of shear to normal stresses ratio on the adhesive ice/substrate strength has been shown. Influence of the ratio of longitudinal and transverse shear stresses on the adhesive bond strength of ice to the substrate has been shown. The natural glacier spectra revealed periodic reduction of AE signals frequency in the middle range of frequencies. The similar effect of AE signals shifting along the frequency axis to the low frequency domain was obtained by testing of freshwater ice samples and related with expansion of the destruction scale. Practical application of the strain AE results for remote determination of the local glacial stability and for studies of glacier ice mechanics is discussed.

  18. Greenland 5 km DEM, Ice Thickness, and Bedrock Elevation Grids, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — A Digital Elevation Model (DEM), ice thickness grid, and bedrock elevation grid of Greenland acquired as part of the PARCA program are available in ASCII text format...

  19. Geophysical Characterization of Fractured Bedrock at Site 8 Former Pease Air Force Base, Newington, New Hampshire

    National Research Council Canada - National Science Library

    Mack, Thomas J; Degnan, James R

    2002-01-01

    Borehole-geophysical logs collected from eight wells and direct-current resistivity data from three survey lines were analyzed to characterize the fractured bedrock and identify transmissive fractures...

  20. Digital bedrock geologic map of parts of the Huntington, Richmond, Bolton and Waterbury quadrangles, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG95-9A Thompson, PJ�and Thompson, TB, 1995, Digital bedrock geologic map of parts of the Huntington, Richmond, Bolton and Waterbury quadrangles,...

  1. Bedrock geologic map of parts of the Eden, Albany, Lowell, and Irasburg quadrangles, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG09-4 (Digitized draft of VG97-5): Kim, J., 2009, Bedrock geologic map of parts of the Eden, Albany, Lowell, and Irasburg quadrangles, VGS...

  2. Geophysical investigations of well fields to characterize fractured-bedrock aquifers in southern New Hampshire

    Science.gov (United States)

    Degnan, James R.; Moore, Richard Bridge; Mack, Thomas J.

    2001-01-01

    Bedrock-fracture zones near high-yield bedrock wells in southern New Hampshire well fields were located and characterized using seven surface and six borehole geophysical survey methods. Detailed surveys of six sites with various methods provide an opportunity to integrate and compare survey results. Borehole geophysical surveys were conducted at three of the sites to confirm subsurface features. Hydrogeologic settings, including a variety of bedrock and surface geologic materials, were sought to gain an insight into the usefulness of the methods in varied terrains. Results from 15 survey lines, 8 arrays, and 3 boreholes were processed and interpreted from the 6 sites. The surface geophysical methods used provided physical properties of fractured bedrock. Seismic refraction and ground-penetrating radar (GPR) primarily were used to characterize the overburden materials, but in a few cases indicated bedrock-fracture zones. Magnetometer surveys were used to obtain background information about the bedrock to compare with other results, and to search for magnetic lows, which may result from weathered fractured rock. Electromagnetic terrain conductivity surveys (EM) and very-low-frequency electromagnetic surveys (VLF) were used as rapid reconnaissance techniques with the primary purpose of identifying electrical anomalies, indicating potential fracture zones in bedrock. Direct-current (dc) resistivity methods were used to gather detailed subsurface information about fracture depth and orientation. Two-dimensional (2-D) dc-resistivity surveys using dipole-dipole and Schlumberger arrays located and characterized the overburden, bedrock, and bedrock-fracture zones through analysis of data inversions. Azimuthal square array dc-resistivity survey results indicated orientations of conductive steep-dipping bedrock-fracture zones that were located and characterized by previously applied geophysical methods. Various available data sets were used for site selection

  3. Graffiti for science: Qualitative detection of erosional patterns through bedrock erosion painting

    Science.gov (United States)

    Beer, Alexander R.; Kirchner, James W.; Turowski, Jens M.

    2016-04-01

    Bedrock erosion is a crucial constraint on stream channel incision, and hence whole landscape evolution, in steep mountainous terrain and tectonically active regions. Several interacting processes lead to bedrock erosion in stream channels, with hydraulic shear detachment, plucking, and abrasion due to sediment impacts generally being the most efficient. Bedrock topography, together with the sediment tools and cover effects, regulate the rate and spatial pattern of in situ surface change. Measurements of natural bedrock erosion rates are valuable for understanding the underlying process physics, as well as for modelling landscape evolution and designing engineered structures. However, quantifying spatially distributed bedrock erosion rates in natural settings is challenging and few such measurements exist. We studied spatial bedrock erosion in a 30m-long bedrock gorge in the Gornera, a glacial meltwater stream above Zermatt. This stream is flushed episodically with sediment-laden streamflow due to hydropower operations upstream, with negligible discharge in the gorge in between these flushing events. We coated several bedrock surface patches with environmentally safe, and water-insoluble outdoor paint to document the spatial pattern of surface abrasion, or to be more precise, to document its driving forces. During four consecutive years, the change of the painted areas was recorded repeatedly with photographs before the painting was renewed. These photographs visually documented the spatial patterns of vertical erosion (channel incision), of lateral erosion (channel widening) and of downstream-directed erosion (channel clearance). The observed qualitative patterns were verified through comparison to quantitative change detection analyses based on annual high-resolution terrestrial laser scanning surveys of the bedrock surfaces. Comparison of repeated photographs indicated a temporal cover effect and a general height limit of the tools effect above the streambed

  4. Abiotic controls of emergent macrophyte density in a bedrock channel - The Cahaba River, AL (USA)

    Science.gov (United States)

    Vaughn, Ryan S.; Davis, Lisa

    2015-10-01

    Research examining bedrock channels is growing. Despite this, biotic-abiotic interactions remain a topic mostly addressed in alluvial systems. This research identified hydrogeomorphic factors operating at the patch-scale (100-102 m) in bedrock shoals of the Cahaba River (AL) that help determine the distribution of the emergent aquatic macrophyte, Justicia americana. Macrophyte patch density (number of stems/m2) and percent bedrock void surface area (rock surface area/m2 occupied by joints, fractures, and potholes) were measured (n = 24 within two bedrock shoals) using stem counts and underwater photography, respectively. One-dimensional hydrologic modeling (HEC-RAS 4.1.0) was completed for a section within a shoal to examine velocity and channel depth as controlling variables for macrophyte patch density. Results from binary logistic regression analysis identified depth and velocity as good predictors of the presence or absence of Justicia americana within shoal structures (depth p = 0.001, velocity p = 0.007), which is a similar finding to previous research conducted in alluvial systems. Correlation analysis between bedrock surface void area and stem density demonstrated a statistically significant positive correlation (r = 0.665, p = 0.01), elucidating a link between abiotic-biotic processes that may well be unique to bedrock channels. These results suggest that the amount of void space present in bedrock surfaces, in addition to localized depth and velocity, helps control macrophyte patch density in bedrock shoal complexes. The utility of geomorphology in explaining patch-scale habitat heterogeneity in this study highlights geomorphology's potential to help understand macrophyte habitat heterogeneity at the reach scale, while also demonstrating its promise for mapping and understanding habitat heterogeneity at the system scale.

  5. The Contraption and Engineering Implementation of Linked Fracture of Shoal Suture in the Bedrock

    OpenAIRE

    Korošec, Ludvik; Kralj, Lojze

    2015-01-01

    The characteristics of overburden strata structural features of typical shallow seam with thin bedrock in Shandong mining area is: there is only one key stratum which controls the overburden strata movement (main roof), when the thickness of bedrock is smaller (generally less than 50-60 m) and the key stratum located under the fissure zone or inside the caving zone through the analysis combined geological data Shandong mining area with the experience in mining practice for a long time. Strata...

  6. SMOS brightness data indicate ice thickness hence bedrock topography in east antarctica

    DEFF Research Database (Denmark)

    Skou, Niels; Kristensen, Steen Savstrup

    2017-01-01

    In order to evaluate a potential calibration target for spaceborne L-band radiometer systems, a 350 × 350 km area near the Concordia station on the East Antarctica plateau was mapped by an airborne L-band radiometer. Unexpectedly, the area showed significant brightness temperature spatial...... variations, well correlated with bedrock topography, hence ice thickness. Using SMOS data over a poorly known part of Antarctica, ice thickness in this area has been assessed, and an existing bedrock map has been improved....

  7. Lipid residues preserved in sheltered bedrock features at Gila Cliff Dwellings National Monument, New Mexico

    Directory of Open Access Journals (Sweden)

    Tammy Buonasera

    2016-10-01

    Bedrock features represent various economic, social, and symbolic aspects of past societies, but have historically received little study, particularly in North America. Fortunately, new techniques for analyzing spatial configurations, use-wear, and organic residues are beginning to unlock more of the interpretive potential of these features. Though preliminary in nature, the present study contributes to this trend by documenting an application of lipid analysis to bedrock features in a dry rockshelter. Results of this initial application indicate that bedrock features in dry rockshelters may provide especially favorable conditions for the preservation and interpretation of ancient organic residues. Abundant lipids, comparable to concentrations present in some pottery sherds, were extracted from a bedrock grinding surface at Gila Cliff Dwellings National Monument and analyzed using gas chromatography-mass spectrometry. Though the lipids were highly oxidized, degradation products indicative of former unsaturated fatty acids were retained. Comparisons to experimentally aged residues, and absence of a known biomarker for maize, indicate that the bulk of the lipids preserved in the milling surface probably derive from processing an oily nut or seed resource, and not from processing maize. Substantially lower amounts of lipids were recovered from a small, blackened cupule. It is hypothesized that some portion of the lipids in the blackened cupule was deposited from condensed smoke of cooking and heating fires in the caves. Potential for the preservation of organic residues in similar sheltered bedrock contexts is discussed, and a practical method for sampling bedrock features in the field is described.

  8. Laboratory measurements of grain-bedrock interactions using inertial sensors.

    Science.gov (United States)

    Maniatis, Georgios; Hoey, Trevor; Hodge, Rebecca; Valyrakis, Manousos; Drysdale, Tim

    2016-04-01

    Sediment transport in steep mountain streams is characterized by the movement of coarse particles (diameter c.100 mm) over beds that are not fully sediment-covered. Under such conditions, individual grain dynamics become important for the prediction of sediment movement and subsequently for understanding grain-bedrock interaction. Technological advances in micro-mechanical-electrical systems now provide opportunities to measure individual grain dynamics and impact forces from inside the sediments (grain inertial frame of reference) instead of trying to infer them indirectly from water flow dynamics. We previously presented a new prototype sensor specifically developed for monitoring sediment transport [Maniatis et al. EGU 2014], and have shown how the definition of the physics of the grain using the inertial frame and subsequent derived measurements which have the potential to enhance the prediction of sediment entrainment [Maniatis et al. 2015]. Here we present the latest version of this sensor and we focus on beginning of the cessation of grain motion: the initial interaction with the bed after the translation phase. The sensor is housed in a spherical case, diameter 80mm, and is constructed using solid aluminum (density = 2.7 kg.m-3) after detailed 3D-CAD modelling. A complete Inertial Measurement Unit (a combination of micro- accelerometer, gyroscope and compass) was placed at the center of the mass of the assembly, with measurement ranges of 400g for acceleration, and 1200 rads/sec for angular velocity. In a 0.9m wide laboratory flume, bed slope = 0.02, the entrainment threshold of the sensor was measured, and the water flow was then set to this value. The sensor was then rolled freely from a static cylindrical bar positioned exactly on the surface of the flowing water. As the sensor enters the flow we record a very short period of transport (1-1.5 sec) followed by the impact on the channel bed. The measured Total Kinetic Energy (Joules) includes the

  9. Using multi-scale remote sensing techniques to quantify hillslope channel coupling in bedrock landscapes

    Science.gov (United States)

    Neely, A. B.; DiBiase, R.

    2016-12-01

    Quantifying the role of rock material properties in controlling landscape-scale erosion rates is a long-standing problem in geomorphology, yet is necessary for accurate interpretation of spatial and temporal patterns of climate and tectonics encoded in Earth's topography. In bedrock landscapes, rockfall from cliffs commonly provides the largest and strongest clasts to stream networks and, until these clasts are eroded or mobilized, can inhibit channel incision into bedrock. Hillslope and channel morphology are thought to be coupled through a connection between bedrock fracture spacing and the resulting grain size distribution of stream sediment, but field quantification of this effect in bedrock landscapes is difficult due to the inaccessibility of steep terrain and challenges characterizing heterogeneity at a range of scales. Here, we use a suite of nested field and remote sensing techniques to characterize bedrock landscape morphology in the San Jacinto and San Gabriel mountain ranges of Southern California. These ranges have similar climate, granitic bedrock, and topographic relief, but exhibit a 5-fold difference in erosion rate that we hypothesize to be a result of a contrast in bedrock fracture spacing and grain size of channel-bed material. Using airborne lidar-derived elevation point clouds, we show that bedrock cliffs in the San Jacinto Mountains are systematically steeper and taller across all spatial scales compared with those in the San Gabriel Mountains. From georeferenced high-resolution photographs taken from along exposed ridgelines, we constructed cm-scale topographic models of 100-m scale cliffs and debris chutes using Structure-from-Motion (SfM) techniques, in order to quantify (1) the extent of bedrock on hillslopes, (2) the spacing and orientation of bedrock fractures on cliffs, and (3) the grain size of rockfall deposits at the base of cliffs and in headwater channels. Our results highlight the utility of nesting SfM surveys with airborne

  10. The influence of bedrock hydrogeology on catchment-scale nitrate fate and transport in fractured aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Orr, Alison [Arup, 50 Ringsend Road, Dublin 4 (Ireland); School of Planning, Architecture and Civil Engineering, Queen' s University Belfast (United Kingdom); Nitsche, Janka [RPS, West Pier Business Campus, Dun Laoghaire, Co. Dublin (Ireland); School of Planning, Architecture and Civil Engineering, Queen' s University Belfast (United Kingdom); Archbold, Marie [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast (United Kingdom); Environmental Protection Agency, Richview, Clonskeagh Road, Dublin 14 (Ireland); Deakin, Jenny [Environmental Protection Agency, Richview, Clonskeagh Road, Dublin 14 (Ireland); Department of Civil, Structural and Environmental Engineering, Trinity College Dublin (Ireland); Ofterdinger, Ulrich; Flynn, Raymond [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast (United Kingdom)

    2016-11-01

    Characterising catchment scale biogeochemical processes controlling nitrate fate in groundwater constitutes a fundamental consideration when applying programmes of measures to reduce risks posed by diffuse agricultural pollutants to water quality. Combining hydrochemical analyses with nitrate isotopic data and physical hydrogeological measurements permitted characterisation of biogeochemical processes influencing nitrogen fate and transport in the groundwater in two fractured bedrock aquifers with contrasting hydrogeology but comparable nutrient loads. Hydrochemical and isotopic analyses of groundwater samples collected from moderately fractured, diffusely karstified limestone indicated nitrification controlled dissolved nitrogen fate and delivery to aquatic receptors. By contrast nitrate concentrations in groundwater were considerably lower in a low transmissivity highly lithified sandstone and pyrite-bearing shale unit with patchy subsoil cover. Geophysical and hydrochemical investigations showed shallower intervals contained hydraulically active fractures where denitrification was reflected through lower nitrogen levels and an isotopic enrichment ratio of 1.7 between δ{sup 15}N and δ{sup 18}O. Study findings highlight the influence of bedrock hydrogeological conditions on aqueous nitrogen mobility. Investigation results demonstrate that bedrock conditions need to be considered when implementing catchment management plans to reduce the impact of agricultural practices on the quality of groundwater and baseflow in receiving rivers. Nitrate isotopic signatures in the groundwater of a freely draining catchment underlain by a karstified aquifer and a poorly draining aquifer with a low transmissivity aquifer. - Graphical abstract: Contrasting nitrate isotope signatures of groundwater in a free draining catchment underlain by a karstified aquifer and a poorly drained catchment underlain by a low transmissivity aquifer. - Highlights: • Comparison of N fate and

  11. High-resolution monitoring of fluvial bedrock erosion in a natural gorge

    Science.gov (United States)

    Beer, Alexander R.; Turowski, Jens M.

    2014-05-01

    Morphological evolution of terrestrial and planetary landscapes is of increasing interest in the geosciences. In mountainous regions stream development and stream shape as a consequence of the interaction of uplift and erosion is fundamental for surface formation. Bedrock stream sections are prevalent that are routings for water and sediments. Hence, the correct description of bedrock channel evolution is fundamental for landscape modelling. To analyse how in situ erosion rates depend on factors like discharge, sediment transport and topography, there is a need of highly resolved topographic field data that so far is not available. Here we present preliminary outcomes of a change detection study from the Gorner Gorge above Zermatt, Switzerland. The outflow of the Gorner glacier (the Gornera stream) is captured most of the time by a water intake for hydropower production. However this intake is flushed twice a day in summer to purge settled sediments. Then the Gornera, charged with erosive bedload, runs along its natural stream bed that cuts through a roche moutonnée. This bedrock section (25m long, 5m wide and 8m deep) was surveyed repeatedly twice a year benefiting from nearly dry bed conditions during water capturing. A Leica ScanStation C10 was used for capturing high density point clouds (aspired average point spacing 5mm) of the bedrock surfaces. Referencing each of the various scanning positions was conducted using Leica HDS targets attached to fixed anchor bolts in the bedrock, that were surveyed locally with a total station. Resulting DEMs were used to calculate DEMs of difference (DoDs) for the bedrock walls and a huge boulder residing on the gravel bed. Erosion rates are visualised and discussed in respect of to the local spatial arrangement of the bedrock to the stream flow and water level.

  12. Models of bedrock surface and overburden thickness over Olkiluoto island and nearby sea area

    Energy Technology Data Exchange (ETDEWEB)

    Moenkkoenen, H. [WSP Finland Oy, Helsinki (Finland)

    2012-04-15

    In this report, a model of bedrock surface and a model of overburden thickness over the Olkiluoto Island and the nearby sea area are presented. Also in purpose to produce material for biosphere and radionuclide transport modelling, stratigraphy models of different sediment layers were created at two priority areas north and south of the Olkiluoto Island. The work concentrated on the collection and description of available data of bedrock surface and overburden thickness. Because the information on the bedrock surface and overburden is collected from different sources and is based on a number of types of data the quality and applicability of data sets varies. Consequently also the reliability in different parts of the models varies. Input data for the bedrock surface and overburden thickness models include 2928 single points and additional outcrops observations (611 polygons) in the modelled area. In addition, the input data include 173 seismic refraction lines (6534 points) and acousticseismic sounding lines (26655 points from which 13721 points are located in model area) in the Olkiluoto offshore area. The average elevation of bedrock surface in area is 2.1 metres above the sea level. The average thickness of overburden is 2.5 metres varying typically between 2 - 4 metres. Thickest overburden covers (approximately 16 metres) of terrestrial area are located at the western end of the Olkiluoto Island and in sea basin south of the island. (orig.)

  13. Lithology and Bedrock Geotechnical Properties in Controlling Rock and Ice Mass Movements in Mountain Cryosphere

    Science.gov (United States)

    Karki, A.; Kargel, J. S.

    2017-12-01

    Landslides and ice avalanches kill >5000 people annually (D. Petley, 2012, Geology http://dx.doi.org/10.1130/G33217.1); destroy or damage homes and infrastructure; and create secondary hazards, such as flooding due to blocked rivers. Critical roles of surface slope, earthquake shaking, soil characteristics and saturation, river erosional undercutting, rainfall intensity, snow loading, permafrost thaw, freeze-thaw and frost shattering, debuttressing of unstable masses due to glacier thinning, and vegetation burn or removal are well-known factors affecting landslides and avalanches. Lithology-dependent bedrock physicochemical-mechanical properties—especially brittle elastic and shear strength, and chemical weathering properties that affect rock strength, are also recognized controls on landsliding and avalanching, but are not commonly considered in detail in landslide susceptibility assessment. Lithology controls the formation of weakened, weathered bedrock; the formation and accumulation of soils; soil saturation-related properties of grain size distribution, porosity, and permeability; and soil creep related to soil wetting-drying and freeze-thaw. Lithology controls bedrock abrasion and glacial erosion and debris production rates, the formation of rough or smoothed bedrock surface by glaciation, fluvial, and freeze-thaw processes. Lithologic variability (e.g., bedding; fault and joint structure) affects contrasts in chemical weathering rates, porosity, and susceptibility to frost shattering and chemical weathering, hence formation of overhanging outcrops and weakened slip planes. The sudden failure of bedrock or sudden slip of ice on bedrock, and many other processes depend on rock lithology, microstructure (porosity and permeability), and macrostructure (bedding; faults). These properties are sometimes considered in gross terms for landslide susceptibility assessment, but in detailed applications to specific development projects, and in detailed mapping over

  14. An ice flow modeling perspective on bedrock adjustment patterns of the Greenland ice sheet

    Directory of Open Access Journals (Sweden)

    M. Olaizola

    2012-11-01

    Full Text Available Since the launch in 2002 of the Gravity Recovery and Climate Experiment (GRACE satellites, several estimates of the mass balance of the Greenland ice sheet (GrIS have been produced. To obtain ice mass changes, the GRACE data need to be corrected for the effect of deformation changes of the Earth's crust. Recently, a new method has been proposed where ice mass changes and bedrock changes are simultaneously solved. Results show bedrock subsidence over almost the entirety of Greenland in combination with ice mass loss which is only half of the currently standing estimates. This subsidence can be an elastic response, but it may however also be a delayed response to past changes. In this study we test whether these subsidence patterns are consistent with ice dynamical modeling results. We use a 3-D ice sheet–bedrock model with a surface mass balance forcing based on a mass balance gradient approach to study the pattern and magnitude of bedrock changes in Greenland. Different mass balance forcings are used. Simulations since the Last Glacial Maximum yield a bedrock delay with respect to the mass balance forcing of nearly 3000 yr and an average uplift at present of 0.3 mm yr−1. The spatial pattern of bedrock changes shows a small central subsidence as well as more intense uplift in the south. These results are not compatible with the gravity based reconstructions showing a subsidence with a maximum in central Greenland, thereby questioning whether the claim of halving of the ice mass change is justified.

  15. Beyond Tree Throw: Wind, Water, Rock and the Mechanics of Tree-Driven Bedrock Physical Weathering

    Science.gov (United States)

    Marshall, J. A.; Anderson, R. S.; Dawson, T. E.; Dietrich, W. E.; Minear, J. T.

    2017-12-01

    Tree throw is often invoked as the dominant process in converting bedrock to soil and thus helping to build the Critical Zone (CZ). In addition, observations of tree roots lifting sidewalk slabs, occupying cracks, and prying slabs of rock from cliff faces have led to a general belief in the power of plant growth forces. These common observations have led to conceptual models with trees at the center of the soil genesis process. This is despite the observation that tree throw is rare in many forested settings, and a dearth of field measurements that quantify the magnitude of growth forces. While few trees blow down, every tree grows roots, inserting many tens of percent of its mass below ground. Yet we lack data quantifying the role of trees in both damaging bedrock and detaching it (and thus producing soil). By combing force measurements at the tree-bedrock interface with precipitation, solar radiation, wind speed, and wind-driven tree sway data we quantified the magnitude and frequency of tree-driven soil-production mechanisms from two contrasting climatic and lithologic regimes (Boulder and Eel Creek CZ Observatories). Preliminary data suggests that in settings with relatively thin soils, trees can damage and detach rock due to diurnal fluctuations, wind response and rainfall events. Surprisingly, our data suggests that forces from roots and trunks growing against bedrock are insufficient to pry rock apart or damage bedrock although much more work is needed in this area. The frequency, magnitude and style of wind-driven tree forces at the bedrock interface varies considerably from one to another species. This suggests that tree properties such as mass, elasticity, stiffness and branch structure determine whether trees respond to gusts big or small, move at the same frequency as large wind gusts, or are able to self-dampen near-ground sway response to extended wind forces. Our measurements of precipitation-driven and daily fluctuations in root pressures exerted on

  16. Neoseismotectonics and glacial isostatic uplift. Deformations and changes of prevailing conditions in the Swedish bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Moerner, N.A. [Stockholm Univ. (Sweden)

    1997-04-01

    The conclusions from this contribution are that no bedrock repository can be considered to be safely placed in the bedrock at the event of new glaciations, which are to be expected over Sweden in 5, 23, and 60 thousand years AP (following the astronomical, natural or long-term variability). Instead, there are all reasons to expect that such a repository would be seriously damaged, and constitute a threat to the biosphere on Earth. These conclusions are based on an extensive observational network of records on the multiple glacial dynamics and the interaction of different variables. 24 refs.

  17. Geologic evolution of the lower Connecticut River valley: Influence of bedrock geology, glacial deposits, and sea level

    Science.gov (United States)

    Stone, Janet R.; Lewis, Ralph S.

    2016-01-01

    This fieldtrip illustrates the character of the lower Connecticut River bedrock valley, in particular its depth, and the lithology and structure of bedrock units it crosses. It examines the character and distribution of the glaciodeltaic terraces that partially fill the valley and discusses the depth of postglacial incision into them.

  18. Influence of bedrock geology on water chemistry of slope wetlands and headwater streams in the southern Rocky Mountains

    Science.gov (United States)

    Monique LaPerriere Nelson; Charles C. Rhoades; Kathleen A. Dwire

    2011-01-01

    We characterized the water chemistry of nine slope wetlands and adjacent headwater streams in Colorado subalpine forests and compared sites in basins formed on crystalline bedrock with those formed in basins with a mixture of crystalline and sedimentary bedrock. The pH, Ca2+, Mg2+, NH4 +, acid neutralizing capacity, and electrical conductivity of wetland porewater and...

  19. Spatial variability in mycorrhizal hyphae and nutrient and water availability in a soil-weathered bedrock profile

    Science.gov (United States)

    L.M. Egerton-Warburton; R.C. Graham; K.R. Hubbert

    2003-01-01

    We documented the spatial distribution, abundance and molecular diversity of mycorrhizal hyphae and physical and chemical properties of soil-weathered bedrock in a chaparral community that experiences seasonal drought. Because plants in this community were known to rely on bedrock-stored water during the summer, the data were used to evaluate the potential role of...

  20. The keystone species of Precambrian deep bedrock biosphere belong to Burkholderiales and Clostridiales

    OpenAIRE

    L. Purkamo; M. Bomberg; R. Kietäväinen; H. Salavirta; M. Nyyssönen; M. Nuppunen-Puputti; L. Ahonen; I. Kukkonen; M. Itävaara

    2015-01-01

    The bacterial and archaeal community composition and the possible carbon assimilation processes and energy sources of microbial communities in oligotrophic, deep, crystalline bedrock fractures is yet to be resolved. In this study, intrinsic microbial communities from six fracture zones from 180–2300 m depths in Outokumpu bedrock were characterized using high-throughput amplicon sequencing and metagenomic prediction. Comamonadaceae-, ...

  1. INFLUENCE OF SEDIMENT SUPPLY, LITHOLOGY, AND WOOD DEBRIS ON THE DISTRIBUTION OF BEDROCK AND ALLUVIAL CHANNELS

    Science.gov (United States)

    Field surveys in the Willapa River basin, Washington State, indicate that the drainage area?channel slope threshold describing the distribution of bedrock and alluvial channels is influenced by the underlying lithology and that local variations in sediment supply can overwhelm ba...

  2. Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand

    NARCIS (Netherlands)

    Toy, Virginia Gail; Sutherland, Rupert; Townend, John; Allen, Michael John; Becroft, Leeza; Boles, Austin; Boulton, Carolyn; Carpenter, Brett M.; Cooper, Alan; Cox, Simon C.; Daube, Christopher; Faulkner, Daniel R.; Halfpenny, Angela; Kato, Naoki; Keys, Stephen; Kirilova, Martina; Kometani, Yusuke; Little, Timothy; Mariani, Elisabetta; Melosh, Benjamin; Menzies, Catriona D.; Morales, Luiz; Morgan, Chance; Mori, Hiroshi; Niemeijer, André|info:eu-repo/dai/nl/370832132; Norris, Richard; Prior, David J.; Sauer, Katrina; Schleicher, Anja M.; Shigematsu, Norio; Teagle, Damon A H; Tobin, Harold; Valdez, Robert; Williams, Jack; Yeo, Samantha; Baratin, Laura May; Barth, Nicolas; Benson, Adrian; Boese, Carolin; Célérier, Bernard; Chamberlain, Calum J.; Conze, Ronald; Coussens, Jamie; Craw, Lisa; Doan, Mai Linh; Eccles, Jennifer; Grieve, Jason; Grochowski, Julia; Gulley, Anton; Howarth, Jamie; Jacobs, Katrina; Janku-Capova, Lucie; Jeppson, Tamara; Langridge, Robert; Mallyon, Deirdre; Marx, Ray; Massiot, Cécile; Mathewson, Loren; Moore, Josephine; Nishikawa, Osamu; Pooley, Brent; Pyne, Alex; Savage, Martha K.; Schmitt, Doug; Taylor-Offord, Sam; Upton, Phaedra; Weaver, Konrad C.; Wiersberg, Thomas; Zimmer, Martin

    2017-01-01

    During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock

  3. The keystone species of Precambrian deep bedrock biosphere belong to Burkholderiales and Clostridiales

    Science.gov (United States)

    Purkamo, L.; Bomberg, M.; Kietäväinen, R.; Salavirta, H.; Nyyssönen, M.; Nuppunen-Puputti, M.; Ahonen, L.; Kukkonen, I.; Itävaara, M.

    2015-11-01

    The bacterial and archaeal community composition and the possible carbon assimilation processes and energy sources of microbial communities in oligotrophic, deep, crystalline bedrock fractures is yet to be resolved. In this study, intrinsic microbial communities from six fracture zones from 180-2300 m depths in Outokumpu bedrock were characterized using high-throughput amplicon sequencing and metagenomic prediction. Comamonadaceae-, Anaerobrancaceae- and Pseudomonadaceae-related OTUs form the core community in deep crystalline bedrock fractures in Outokumpu. Archaeal communities were mainly composed of Methanobacteraceae-affiliating OTUs. The predicted bacterial metagenomes showed that pathways involved in fatty acid and amino sugar metabolism were common. In addition, relative abundance of genes coding the enzymes of autotrophic carbon fixation pathways in predicted metagenomes was low. This indicates that heterotrophic carbon assimilation is more important for microbial communities of the fracture zones. Network analysis based on co-occurrence of OTUs revealed the keystone genera of the microbial communities belonging to Burkholderiales and Clostridiales. Bacterial communities in fractures resemble those found from oligotrophic, hydrogen-enriched environments. Serpentinization reactions of ophiolitic rocks in Outokumpu assemblage may provide a source of energy and organic carbon compounds for the microbial communities in the fractures. Sulfate reducers and methanogens form a minority of the total microbial communities, but OTUs forming these minor groups are similar to those found from other deep Precambrian terrestrial bedrock environments.

  4. Performance Assessments of a Novel Well Design for Reducing Exposure to Bedrock-Derived Arsenic.

    Science.gov (United States)

    Winston, Richard B; Ayotte, Joseph D

    2017-09-26

    Arsenic in groundwater is a serious problem in New England, particularly for domestic well owners drawing water from bedrock aquifers. The overlying glacial aquifer generally has waters with low arsenic concentrations but is less used because of frequent loss of well water during dry periods and the vulnerability to surface-sourced bacterial contamination. An alternative, novel design for shallow wells in glacial aquifers is intended to draw water primarily from unconsolidated glacial deposits, while being resistant to drought conditions and surface contamination. Its use could greatly reduce exposure to arsenic through drinking water for domestic use. Hypothetical numerical models were used to investigate the potential hydraulic performance of the new well design in reducing arsenic exposure. The aquifer system was divided into two parts, an upper section representing the glacial sediments and a lower section representing the bedrock. The location of the well, recharge conditions, and hydraulic properties were systematically varied in a series of simulations and the potential for arsenic contamination was quantified by analyzing groundwater flow paths to the well. The greatest risk of arsenic contamination occurred when the hydraulic conductivity of the bedrock aquifer was high, or where there was upward flow from the bedrock aquifer because of the position of the well in the flow system. © 2017, National Ground Water Association.

  5. Morphodynamic simulation of sediment deposition patterns on a recently stripped bedrock anastomosed channel

    Directory of Open Access Journals (Sweden)

    D. Milan

    2018-04-01

    Full Text Available Some mixed bedrock-alluvial dryland rivers are known to undergo cycles of alluvial building during low flow periods, punctuated by stripping events during rare high magnitude flows. We focus on the Olifants River, Kruger National Park, South Africa, and present 2-D morphodynamic simulations of hydraulics and sediment deposition patterns over an exposed bedrock anastomosed pavement. We examine the assumptions underlying a previous conceptual model, namely that sedimentation occurs preferentially on bedrock highs. Our modelling results and local field observations in fact show that sediment thicknesses are greater over bedrock lows, suggesting these are the key loci for deposition, barform initiation and island building. During peak flows, velocities in the topographic lows tend to be lower than in intermediate topographic areas. It is likely that intermediate topographic areas supply sediment to the topographic lows at this flow stage, which is then deposited in the lows on the falling limb of the hydrograph as velocities reduce. Subsequent vegetation establishment on deposits in the topographic lows is likely to play a key role in additional sedimentation and vegetation succession, both through increasing the cohesive strength of alluvial units and by capturing new sediments and propagules.

  6. Burial and Exhumation of Inner Shelf Bedrock Reefs due to Winter Storms

    Science.gov (United States)

    Storlazzi, C. D.; Fregoso, T.; Golden, N.; Finlayson, D. P.

    2009-12-01

    Repeated bathymetric and acoustic backscatter sonar surveys were conducted along the energetic emergent inner shelf of northern Monterey Bay, CA, USA, in the fall of 2005 and the spring of 2006 to determine the impact of winter storm waves, beach erosion, and river floods on biologically important bedrock reef habitats. The surveys were conducted using a 234 kHz interferometric swath side-scan sonar system that provided a horizontal resolution on the order of 10 cm and a vertical resolution of approximately 50 cm. The surveys extended from water depths of 2 m to 25 m and covered an area of 3.2 km^2, 37% of which was bedrock and the remainder of which was unconsolidated sediment. Our analyses of the bathymetric and acoustic backscatter data from the sonar surveys demonstrated that 28% of the bedrock reefs in the study area were either buried or exhumed during the 6 month study interval along this stretch of energetic coastline. While much of the detected change was at the boundary between bedrock and unconsolidated sediment due to sedimentation or erosion, in a number of cases the change in seabed character was due to changes in sediment grain size apparently due to scour or burial. These findings suggest that, in some cases, single mapping cruises typically employed for habitat and geologic characterization may not adequately characterize the geomorphology and sedimentologic nature of energetic inner shelves.

  7. Digital compilation bedrock geologic map of the Mt. Ellen quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG95-6A Stanley, RS, Walsh, G, Tauvers, PR, DiPietro, JA, and DelloRusso, V, 1995,�Digital compilation bedrock geologic map of the Mt. Ellen...

  8. Bedrock geologic map of the Jay and North Troy area, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG97-04C Stanley, RS, and Roy, D, 1997,�Bedrock geologic map of the Jay and North Troy area, Vermont: VGS Open-File Report VG97-04c, scale 1:24000....

  9. Digital compilation bedrock geologic map of the South Mountain quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG95-3A Stanley, R.S., DelloRusso, V., Tauvers, P.R., DiPietro, J.A., Taylor, S., and Prahl, C., 1995, Digital compilation bedrock geologic map of...

  10. Investigating Bedrock through Canopy Structure, Organization and Connectivity of an Arctic Watershed

    Science.gov (United States)

    Dafflon, B.; Leger, E.; Peterson, J.; Ulrich, C.; Soom, F.; Biraud, S.; Tran, A. P.; Wainwright, H. M.; Ajo Franklin, J. B.; Hubbard, S. S.

    2016-12-01

    Improving understanding of Arctic ecosystem functioning and parameterization of process-rich models that simulate feedbacks to a changing climate require advances in quantifying ecosystem properties, from within the bedrock to the top of the canopy. In Arctic regions having significant elevation gradients and subsurface heterogeneity (bedrock, permafrost, ground ice), quantifying surface and subsurface structure, organization and connectivity of watershed elements is particularly challenging yet is critical for predicting the storage and flux of carbon in a changing climate. In this study, we evaluate linkages between physical properties (incl. fraction of soil constituents, bedrock depth, permafrost characteristics), hydrological conditions and geomorphic characteristics. This study takes place in a Seward Peninsula Watershed near Nome AK, which is characterized by an elevation gradient, extensive bedrock, and discontinuous permafrost. We use a multi-method acquisition strategy to characterize below and above ground properties and their linkages, including point-scale measurements, electrical resistivity tomography, seismic refraction and UAS-based low-altitude aerial imaging. Data integration and analysis is supported by numerical approaches that simulate dynamic hydrological and thermal processes. Overall, this study enables the identification of watershed structure and the links between various soil (incl., water content, temperature, electrical conductivity), landscape properties (incl. wetness conditions, vegetation, topographic metrics) and the bedrock/permafrost distribution and characteristics in a representative Arctic watershed. Low-altitude aerial imaging shows promise to extend the landscape organization analysis approach to larger regions in the Arctic. The obtained information about organization and connectivity of the landscape is expected to be useful for improving predictions of Arctic ecosystem feedbacks to climate.

  11. Detections of MTBE in surficial and bedrock aquifers in New England

    International Nuclear Information System (INIS)

    Grady, S.J.

    1995-01-01

    The gasoline additive methyl tert-butyl ether (MTBE) was detected in 24% of water samples collected from surficial and bedrock aquifers in areas of New England. MTBE was the most frequently detected volatile organic compound among the 60 volatile chemicals analyzed and was present in 33 of 133 wells sampled from July 1993 through September 1995. The median MTBE concentration measured in ground-water samples was 0.45 microgram per liter and concentrations ranged from 0.2 to 5.8 microgram per liter. The network of wells sampled for MTBE consisted of 103 monitoring wells screened in surficial sand-and-gravel aquifers and 30 domestic-supply wells in fractured crystalline bedrock aquifers. Seventy-seven percent of all MTBE detections were from 26 shallow monitoring wells screened in surficial aquifers. MTBE was detected in42% of monitoring wells in urban areas. In agricultural areas, MTBE was detected i 8% (2 of 24) of wells and was not detected in undeveloped areas. Sixty-two percent of the MTBE detections in surficial aquifers were from wells within 0.25 mile of gasoline stations or underground gasoline storage tanks; all but one of these wells were in Connecticut and Massachusetts, where reformulated gasoline is used. MTBE was detected in 23% of deep domestic-supply wells that tapped fractured bedrock aquifers. MTBE was detected in bedrock wells only in Connecticut and Massachusetts; land use near the wells was suburban to rural, and none of the sampled bedrock wells were within 0.25 mile of a gasoline station

  12. Hydrogeology of a drift-filled bedrock valley near Lino Lakes, Anoka County, Minnesota

    Science.gov (United States)

    Winter, T.C.; Pfannkuch, H.O.

    1976-01-01

    The bedrock surface of east-central Minnesota is dissected by an intricate network of valleys. Outside the bedrock valley at site B, 3 mi (4. 8 km) from site A, 100 ft (30 m) of drift overlies the bedrock surface. Observation wells were installed at the two sites to determine the vertical ground-water movement between the various aquifer units and the lateral movement between the two sites. An aquifer test of the lowest valley-fill aquifer at site A showed that the observation well completed in the same aquifer as the pumping well responded immediately; whereas a lag of about 100 min occurred between the lower valley fill and uppermost body of sand and gravel. This indicates that the hydraulic connection between these two layers is poor at the immediate site. Test results show that the lower sand-and-gravel aquifer has a transmissivity between 14,000 and 27,000 ft2/d (1,300 and 2,500 m2/d). Although the hydraulic gradient is vertically downward in the valley, much of the drift fill is poorly permeable. This suggests that the quantity of downward-percolating water reaching the lowest valley-fill aquifer is relatively small at the test site. Because valley cut through a number of bedrock aquifers in the region, they could potentially be an important avenue of contamination from land-surface waste. In addition, the vast network of bedrock valleys in the Twin Cities area might cause contaminants to disseminate rather rapidly throughout a large area.

  13. Application of Microtremor Array Analysis to Estimate the Bedrock Depth in the Beijing Plain area

    Science.gov (United States)

    Xu, P.; Ling, S.; Liu, J.; Su, W.

    2013-12-01

    With the rapid expansion of large cities around the world, urban geological survey provides key information regarding resource development and urban construction. Among the major cities of the world, China's capital city Beijing is among the largest cities possessing complex geological structures. The urban geological survey and study in Beijing involves the following aspects: (1) estimating the thickness of the Cenozoic deposit; (2) mapping the three-dimensional structure of the underlying bedrock, as well as its relations to faults and tectonic settings; and (3) assessing the capacity of the city's geological resources in order to support its urban development and operation safety. The geological study of Beijing in general was also intended to provide basic data regarding the urban development and appraisal of engineering and environment geological conditions, as well as underground space resources. In this work, we utilized the microtremor exploration method to estimate the thickness of the bedrock depth, in order to delineate the geological interfaces and improve the accuracy of the bedrock depth map. The microtremor observation sites were located in the Beijing Plain area. Traditional geophysical or geological survey methods were not effective in these areas due to the heavy traffic and dense buildings in the highly-populated urban area. The microtremor exploration method is a Rayleigh-wave inversion technique which extracts its phase velocity dispersion curve from the vertical component of the microtremor array records using the spatial autocorrelation (SPAC) method, then inverts the shear-wave velocity structure. A triple-circular array was adopted for acquiring microtremor data, with the observation radius in ranging from 40 to 300 m, properly adjusted depending on the geological conditions (depth of the bedrock). The collected microtremor data are used to: (1) estimation of phase velocities of Rayleigh-wave from the vertical components of the microtremor

  14. The influence of bed roughness on partial alluviation in an experimental bedrock channel

    Science.gov (United States)

    Davis, J. R.; Sklar, L. S.; Demeter, G. I.; Johnson, J. P.; Whipple, K. X.

    2005-12-01

    The extent of alluvial cover on a bedrock channel bed strongly influences the efficiency of river incision, and can affect the quality of habitat for aquatic ecosystems. The extent of partial cover is commonly modeled as a simple function of sediment supply relative to the transport capacity of the stream, although other factors are likely to be important, particularly the roughness of the underlying bedrock surface. Here we report results of a set of laboratory experiments investigating the influence of bedrock channel bed topography on the dynamics of partial bed alluviation. The experiments were conducted in a tilting flume 8 m long and 0.3 m wide with an erodible bedrock bed made of a sand-cement mixture. The flume has a calibrated sediment feed and a double-basket sediment trap that provides a continuous record of sediment flux out of the downstream end. We used a uniform grain size of 5 mm, and varied the sediment supply rate from zero to that sufficient to create a fully alluviated bed. We created a variety of bedrock roughness conditions, from smooth, nearly planar surfaces to an egg-carton texture made with a plaster-coated foam mold. Intermediate roughness was achieved by chiseling into smooth beds and by allowing the bed topography to evolve by sustained bedload abrasion. We used a laser microtopography scanning device to make topographic maps of the bed surface, with a vertical resolution of 0.2 mm and a horizontal spacing of 5 mm. From these data we quantify bedrock bed roughness as the standard deviation of the distribution of bed elevations relative to a plane inclined at the mean bed slope. To guide our selection of bed roughness values we made topographic surveys of a number of bedrock channel beds, including partially alluviated channels where we dug trenches through alluvial deposits to expose the underlying bedrock surface. For each bed roughness condition we systematically varied the sediment supply rate and repeatedly mapped the extent of

  15. Human enteric viruses in groundwater from a confined bedrock aquifer

    Science.gov (United States)

    Borchardt, M. A.; Bradbury, K.R.; Gotkowitz, M.B.; Cherry, J.A.; Parker, B.L.

    2007-01-01

    Confined aquifers are overlain by low-permeability aquitards that are commonly assumed to protect underlying aquifers from microbial contaminants. However, empirical data on microbial contamination beneath aquitards is limited. This study determined the occurrence of human pathogenic viruses in well water from a deep sandstone aquifer confined by a regionally extensive shale aquitard. Three public water-supply wells were each sampled 10 times over 15 months. Samples were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) for several virus groups and by cell culture for infectious enteroviruses. Seven of 30 samples were positive by RT-PCR for enteroviruses; one of these was positive for infectious echovirus 18. The virus-positive samples were collected from two wells cased through the aquitard, indicating the viruses were present in the confined aquifer. Samples from the same wells showed atmospheric tritium, indicating water recharged within the past few decades. Hydrogeologic conditions support rapid porous media transport of viruses through the upper sandstone aquifer to the top of the aquitard 61 m below ground surface. Natural fractures in the shale aquitard are one possible virus transport pathway through the aquitard; however, windows, cross-connecting well bores, or imperfect grout seals along well casings also may be involved. Deep confined aquifers can be more vulnerable to contamination by human viruses than commonly believed. ?? 2007 American Chemical Society.

  16. Final disposal of spent nuclear fuel in Finnish bedrock - Romuvaara site report

    Energy Technology Data Exchange (ETDEWEB)

    Anttila, P. [Fortum Engineering Oy (Finland); Ahokas, H. [Fintact Oy (Finland); Front, K. [VTT Communities and Infrastructure, Espoo (Finland)] [and others

    1999-06-01

    Posiva Oy is studying the Finnish bedrock for the geological disposal of spent nuclear fuel. The study is based on the site selection research programme started originally in 1983. The programme is in accordance with the decision in principle by the Council of State in 1983 and aims at the selection of one site in 2000. Four sites, Haestholmen in Loviisa, Kivetty in Aeaenekoski, Olkiluoto in Eurajoki and Romuvaara in Kuhmo, have been studied in detail. This report summarises the results of the site investigations carried out at Romuvaara. The bedrock of Romuvaara belongs to the Archean basement complex, whose oldest parts date back over 2800 million years. The bedrock consists mainly of migmatitic banded gneisses (tonalite, leucotonalite and mica gneiss), which are cut by granodiorite and metadiabase dykes. The rocks, excluding the metadiabase, have undergone a polyphase Archaean deformation. Altogether 31 bedrock structures (R-structures) have been modelled at the investigation site, most of them representing steeply dipping fracture zones. The rock mass between the fracture zones represents what is termed `intact rock`, which is typically hard, unweathered and sparsely fractured. The R-structures are generally hydraulically more conductive than the intact rock and their mean transmissivity is 1.6 x 10{sup -7} m{sup 2}/s. The corresponding mean of the hydraulic conductivity values for the intact rock measured using a 2 m packer interval is 8 x 10{sup -12} m/s, if a lognormal distribution for all measured values is assumed. A clear decrease in hydraulic conductivity with depth has been found, for both the R-structures and the intact rock. In addition, the hydraulically conductive fractures seem to be more frequent and their transmissivities higher in the uppermost 100 - 200 m of the bedrock than at greater depths. The groundwater of Romuvaara is classified as fresh water and the Total Dissolved Solids (TDS) and chloride contents increase with depth. The chemically

  17. Application of Seismic Observation Data in Borehole for the Development of Attenuation Equation of Response Spectra on Bedrock

    International Nuclear Information System (INIS)

    Si, Hongjun

    2014-01-01

    Ground motion data on seismic bedrock is important, but it is very difficult to obtain such data directly. The data from KiK-net and JNES/SODB is valuable and very useful in developing the attenuation relationship of response spectra on seismic bedrock. NIED has approximately 200 observation points on seismic bedrock with S-wave velocity of more than 2000 m/s in Japan. Using data from observation at these points, a Ground Motion Prediction Equation (GMPE) is under development. (author)

  18. DECIPHERING THE FINEST IMPRINT OF GLACIAL EROSION: OBJECTIVE ANALYSIS OF STRIAE PATTERNS ON BEDROCK

    Directory of Open Access Journals (Sweden)

    Piet Stroeven

    2011-05-01

    Full Text Available The aim of this study is to compare the efficiency of different mathematical and statistical geometrical methods applied to characterise the orientation distribution of striae on bedrock for deciphering the finest imprint of glacial erosion. The involved methods include automatic image analysis techniques of Fast Fourier Transform (FFT, and the experimental investigations by means of Saltikov's directed secants analysis (rose of intersection densities, applied to digital and analogue images of the striae pattern, respectively. In addition, the experimental data were compared with the modelling results made on the basis of Underwood's concept of linear systems in a plane. The experimental and modelling approaches in the framework of stereology yield consistent results. These results reveal that stereological methods allow a reliable and efficient delineation of different families of glacial striae from a complex record imprinted in bedrock.

  19. Study on Strata Behavior Regularity of 1301 Face in Thick Bedrock of Wei - qiang Coal Mine

    Science.gov (United States)

    Gu, Shuancheng; Yao, Boyu

    2017-09-01

    In order to ensure the safe and efficient production of the thick bedrock face, the rule of the strata behavior of the thick bedrock face is discussed through the observation of the strata pressure of the 1301 first mining face in Wei qiang coal mine. The initial face is to press the average distance of 50.75m, the periodic weighting is to press the average distance of 12.1m; during the normal mining period, although the upper roof can not be broken at the same time, but the pressure step is basically the same; the working face for the first weighting and periodical weighting is more obvious to the change of pressure step change, when the pressure of the working face is coming, the stent force increased significantly, but there are still part of the stent work resistance exceeds the rated working resistance, low stability, still need to strengthen management.

  20. Faulting in unconsolidated sediments and bedrock east of Toronto - phase 1

    International Nuclear Information System (INIS)

    Rogojina, C.; Mohajer, A.A.; Eyles, N.

    1995-10-01

    Increasing concern with the potential earthquake hazard in southern Ontario has focused attention on neotectonic structures affecting bedrock. Within the boundaries of the metropolitan Toronto area (632 km 2 ), about 2500 fracture orientations have been measured in more than 70 bedrock outcrops. An east-northeast systematic fracture set constitute the most commonly-oriented fundamental fracture system in the study area. The east-northeast systematic fracture set may be the product of the current compressive stress field combined with regional uplift, but this should be confirmed by further field investigation. Anomalous fracture patterns were identified at the periphery of Metropolitan Toronto, specifically along the West Humber and Rouge rivers. Four post-glacial pop-ups were identified within Metro Toronto. Careful mapping and description of these pop-ups show a possible relationship with the contemporary principal stresses in the area and the local fracture pattern. (author). 41 refs., 8 figs

  1. Areally Extensive Surface Bedrock Exposures on Mars: Many Are Clastic Rocks, Not Lavas

    Science.gov (United States)

    Rogers, A. Deanne; Warner, Nicholas H.; Golombek, Matthew P.; Head, James W.; Cowart, Justin C.

    2018-02-01

    Areally extensive exposures of intact olivine/pyroxene-enriched rock, as well as feldspar-enriched rock, are found in isolated locations throughout the Martian highlands. The petrogenetic origin(s) of these rock units are not well understood, but some previous studies favored an effusive volcanic origin partly on the basis of distinctive composition and relatively high thermal inertia. Here we show that the regolith development, crater retention, and morphological characteristics for many of these "bedrock plains" are not consistent with competent lavas and reinterpret the high thermal inertia orbital signatures to represent friable materials that are more easily kept free of comminution products through eolian activity. Candidate origins include pyroclastic rocks, impact-generated materials, or detrital sedimentary rocks. Olivine/pyroxene enrichments in bedrock plains relative to surrounding materials could have potentially formed through deflation and preferential removal of plagioclase.

  2. Preliminary Assessment of Water Levels in Bedrock Wells in New Hampshire, 1984 to 2007

    Science.gov (United States)

    Ayotte, Joseph D.; Kernen, Brandon M.; Wunsch, David R.; Argue, Denise M.; Bennett, Derek S.; Mack, Thomas J.

    2010-01-01

    Analysis of nearly 60,000 reported values of static water level (SWL, as depth below land surface) in bedrock wells in New Hampshire, aggregated on a yearly basis, showed an apparent deepening of SWL of about 13 ft (4 m) over the period 1984–2007. Water-level data were one-time measurements at each well and were analyzed, in part, to determine if they were suitable for analysis of trends in groundwater levels across the state. Other well characteristics, however, also have been changing over time, such as total well depth, casing length, the length of casing in bedrock, and to some extent, well yield. Analyses indicated that many of the well construction variables are significantly correlated; the apparent declines in water levels may have been caused by some of these factors. Information on changes in water use for the period was not available, although water use may be an important factor affecting water levels.

  3. Global distribution of bedrock exposures on Mars using THEMIS high-resolution thermal inertia

    Science.gov (United States)

    Edwards, C.S.; Bandfield, J.L.; Christensen, P.R.; Fergason, R.L.

    2009-01-01

    We investigate high thermal inertia surfaces using the Mars Odyssey Thermal Emission Imaging System (THEMIS) nighttime temperature images (100 m/pixel spatial sampling). For this study, we interpret any pixel in a THEMIS image with a thermal inertia over 1200 J m-2 K-1 s-1/2 as "bedrock" which represents either in situ rock exposures or rock-dominated surfaces. Three distinct morphologies, ranked from most to least common, are associated with these high thermal inertia surfaces: (1) valley and crater walls associated with mass wasting and high surface slope angles; (2) floors of craters with diameters >25 km and containing melt or volcanics associated with larger, high-energy impacts; and (3) intercrater surfaces with compositions significantly more mafic than the surrounding regolith. In general, bedrock instances on Mars occur as small exposures (less than several square kilometers) situated in lower-albedo (thermal inertia (>350 J m-2 K-1 s-1/2), and relatively dust-free (dust cover index <0.95) regions; however, there are instances that do not follow these generalizations. Most instances are concentrated in the southern highlands, with very few located at high latitudes (poleward of 45oN and 58oS), suggesting enhanced mechanical breakdown probably associated with permafrost. Overall, Mars has very little exposed bedrock with only 960 instances identified from 75oS to 75oN with likely <3500 km2 exposed, representing???1% of the total surface area. These data indicate that Mars has likely undergone large-scale surface processing and reworking, both chemically and mechanically, either destroying or masking a majority of the bedrock exposures on the planet. Copyright 2009 by the American Geophysical Union.

  4. Ice/Bedrock Feedbacks as a Principle Contributor to Glacial-Interglacial Oscillations

    Science.gov (United States)

    Kimmel, J.; Lee, K.; Jackson, C. H.

    2014-12-01

    Since the mid-Pleistocene, the oscillation between glacial and interglacial climate states occurs with a period of approximately 100 kyr. Each cycle is comprised of a slow glaciation with a subsequent rapid deglaciation. While the solar forcing is clearly an important driver for these transitions, the power spectrum of the solar forcing is quite different from the subsequent climate response and, in general, does not have a noticeable correlation with global ice volume. Instead, previous studies have shown that internal climate processes and their interactions (e.g., CO2, water vapor, isostatic bed response) play a significant role in producing these global climate cycles. The rapid retreat of large ice sheets at the start of an interglacial is often attributed to the interaction between surface and atmospheric processes. While calving is thought to amplify this retreat, it is not typically considered a principle driver of the ice sheet response. Our study investigates the potential for ice/bedrock feedbacks to be a principle contributor in shaping the glacial-interglacial climate oscillation -- particularly the rapid deglaciation that precedes an interglacial. The ice sheet model we develop includes a piecewise linear ice/bedrock feedback while atmospheric and surface processes are taken to be as simple as possible. Due to the long timescale of the bedrock response and the rapid mass loss due to calving, the model ice sheet exhibits rapid deglaciation from a stable maximum when it retreats through an overdeepening. However, ice sheet advance is also shown to be as rapid unless a more complex bedrock response is considered. In particular, we show that a forebulge created by the displacement of the mantle adds a new stable branch to the volume/equilibrium line bifurcation diagram that results in slower growth of the ice sheet during glaciation.

  5. Bedrock knobs, San Francisco Bay: Do navigation hazards outweigh other environment problems?

    Science.gov (United States)

    Carlson, P.R.; Chin, J.L.; Wong, F.L.

    2000-01-01

    Three bedrock knobs (Arch, Harding, and Shag rocks) rise above the unconsolidated sediment of central San Francisco Bay to a water depth of less than -12 m (cities of the Bay estuary. Acoustic profiling data show that bedrock extends at a gentle to moderate slope away from the knobs. These data also show that two of the knobs, Harding and Shag, may be part of a bedrock ridge that extends to Alcatraz Island and perhaps southeast to Blossom Rock. The tops of these rocks should be lowered to a depth of -17 m (-55.8 ft), with a total volume of as much as 245,000 m3 (320,460 yd3), at an estimated cost of nearly 27 million dollars, to eliminate the possibility that a tanker would strike one and rupture. A resulting large oil spill would likely cost many times more than the 10 million dollars needed to clean up a small 1996 spill. If the rocks were removed, local habitat for striped bass and other game fish would be altered, with potential negative impact on sport fishing. Currently, public officials are studying the benefits to the Bay environment of lowering the rock knobs.

  6. The influence of bedrock hydrogeology on catchment-scale nitrate fate and transport in fractured aquifers.

    Science.gov (United States)

    Orr, Alison; Nitsche, Janka; Archbold, Marie; Deakin, Jenny; Ofterdinger, Ulrich; Flynn, Raymond

    2016-11-01

    Characterising catchment scale biogeochemical processes controlling nitrate fate in groundwater constitutes a fundamental consideration when applying programmes of measures to reduce risks posed by diffuse agricultural pollutants to water quality. Combining hydrochemical analyses with nitrate isotopic data and physical hydrogeological measurements permitted characterisation of biogeochemical processes influencing nitrogen fate and transport in the groundwater in two fractured bedrock aquifers with contrasting hydrogeology but comparable nutrient loads. Hydrochemical and isotopic analyses of groundwater samples collected from moderately fractured, diffusely karstified limestone indicated nitrification controlled dissolved nitrogen fate and delivery to aquatic receptors. By contrast nitrate concentrations in groundwater were considerably lower in a low transmissivity highly lithified sandstone and pyrite-bearing shale unit with patchy subsoil cover. Geophysical and hydrochemical investigations showed shallower intervals contained hydraulically active fractures where denitrification was reflected through lower nitrogen levels and an isotopic enrichment ratio of 1.7 between δ(15)N and δ(18)O. Study findings highlight the influence of bedrock hydrogeological conditions on aqueous nitrogen mobility. Investigation results demonstrate that bedrock conditions need to be considered when implementing catchment management plans to reduce the impact of agricultural practices on the quality of groundwater and baseflow in receiving rivers. Nitrate isotopic signatures in the groundwater of a freely draining catchment underlain by a karstified aquifer and a poorly draining aquifer with a low transmissivity aquifer. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Bedrock geologic map of the central block area, Yucca Mountain, Nye County, Nevada

    International Nuclear Information System (INIS)

    Day, W.C.; Potter, C.J.; Sweetkind, D.S.; Dickerson, R.P.; San Juan, C.A.

    1998-01-01

    Bedrock geologic maps form the foundation for investigations that characterize and assess the viability of the potential high-level radioactive waste repository at Yucca Mountain, Nevada. This study was funded by the US Department of Energy Yucca Mountain Project to provide a detailed (1:6,000-scale) bedrock geologic map for the area within and adjacent to the potential repository area at Yucca Mountain, Nye County, Nevada. Prior to this study, the 1:12,000-scale map of Scott and Bon, (1984) was the primary source of bedrock geologic data for the Yucca Mountain Project. However, targeted detailed mapping within the central block at Yucca Mountain revealed structural complexities along some of the intrablock faults that were not evident at 1:12,000 (Scott and Bonk, 1984). As a result, this study was undertaken to define the character and extent of the dominant structural features in the vicinity of the potential repository. In addition to structural considerations, ongoing subsurface excavation and geologic mapping within the exploratory Studies Facility (ESF), development of a three-dimensional-framework geologic model, and borehole investigations required use of a constituent stratigraphic system to facilitate surface to underground comparisons. The map units depicted in this report correspond as closely as possible to the proposed stratigraphic nomenclature by Buesch and others (1996), as described here

  8. Beneath it all: bedrock geology of the Catskill Mountains and implications of its weathering.

    Science.gov (United States)

    Ver Straeten, Charles A

    2013-09-01

    The Devonian-age bedrock of the Catskill Mountains has been the focus of many studies. This paper reviews the character and composition of the rocks of the Catskills, and examines weathering (rock decay) processes and their implications in the Catskills. Rocks of the Catskills and closest foothills consist of siliciclastic rocks (sandstones, mudrocks, conglomerates) with minimal, locally dispersed carbonate rocks. The former are dominated by quartz, metamorphic and sedimentary rock fragments, and clay minerals. Other minor sediment components include cements, authigenic and heavy minerals, and fossil organic matter. Physical, chemical, and biological weathering of the Catskill bedrock since uplift of the Appalachian region, combined with glaciation, have dissected a plateau of nearly horizontally layered rocks into a series of ridges, valleys, and peaks. The varied weathering processes, in conjunction with many factors (natural and anthropogenic), fragment the rocks, forming sediment and releasing various elements and compounds. These may have positive, neutral, or negative implications for the region's soils, waters, ecology, and human usage. A new generation of studies and analyses of the Catskill bedrock is needed to help answer a broad set of questions and problems across various fields of interest. © 2013 New York Academy of Sciences.

  9. Modeling early in situ wetting of a compacted bentonite buffer installed in low permeable crystalline bedrock

    Science.gov (United States)

    Dessirier, B.; Frampton, A.; Fransson, À.; Jarsjö, J.

    2016-08-01

    The repository concept for geological disposal of spent nuclear fuel in Sweden and Finland is planned to be constructed in sparsely fractured crystalline bedrock and with an engineered bentonite buffer to embed the waste canisters. An important stage in such a deep repository is the postclosure phase following the deposition and the backfilling operations when the initially unsaturated buffer material gets hydrated by the groundwater delivered by the natural bedrock. We use numerical simulations to interpret observations on buffer wetting gathered during an in situ campaign, the Bentonite Rock Interaction Experiment, in which unsaturated bentonite columns were introduced into deposition holes in the floor of a 417 m deep tunnel at the Äspö Hard Rock Laboratory in Sweden. Our objectives are to assess the performance of state-of-the-art flow models in reproducing the buffer wetting process and to investigate to which extent dependable predictions of buffer wetting times and saturation patterns can be made based on information collected prior to buffer insertion. This would be important for preventing insertion into unsuitable bedrock environments. Field data and modeling results indicate the development of a de-saturated zone in the rock and show that in most cases, the presence or absence of fractures and flow heterogeneity are more important factors for correct wetting predictions than the total inflow. For instance, for an equal open-hole inflow value, homogeneous inflow yields much more rapid buffer wetting than cases where fractures are represented explicitly thus creating heterogeneous inflow distributions.

  10. Bedrock Canyons Carved by the Largest Known Floods on Earth and Mars

    Science.gov (United States)

    Lamb, M. P.; Lapôtre, M. G. A.; Larsen, I. J.; Williams, R. M. E.

    2017-12-01

    The surface of Earth is a dynamic and permeable interface where the rocky crust is sculpted by ice, wind and water resulting in spectacular mountain ranges, vast depositional basins and environments that support life. These landforms and deposits contain a rich, yet incomplete, record of Earth history that we are just beginning to understand. Some of the most dramatic landforms are the huge bedrock canyons carved by catastrophic floods. On Mars, similar bedrock canyons, known as Outflow Channels, are the most important indicators of large volumes of surface water in the past. Despite their importance and now decades of observations of canyon morphology, we lack a basic understanding of how the canyons formed, which limits our ability to reconstruct flood discharge, duration and water volume. In this presentation I will summarize recent work - using mechanistic numerical models and field observations - that suggests that bedrock canyons carved by megafloods rapidly evolve to a size and shape such that boundary shear stresses just exceed that required to entrain fractured blocks of rock. The threshold shear stress constraint allows for quantitative reconstruction of the largest known floods on Earth and Mars, and implies far smaller discharges than previous methods that assume flood waters fully filled the canyons to high water marks.

  11. Characterising Bedrock Aquifer Systems in Korea Using Paired Water-Level Monitoring Data

    Directory of Open Access Journals (Sweden)

    Jae Min Lee

    2017-06-01

    Full Text Available This study focused on characterising aquifer systems based on water-level changes observed systematically at 159 paired groundwater monitoring wells throughout Korea. Using spectral analysis, principal component analysis (PCA, and cross-correlation analysis with linear regression, aquifer conditions were identified from the comparison of water-level changes in shallow alluvial and deep bedrock monitoring wells. The spectral analysis could identify the aquifer conditions (i.e., unconfined, semi-confined and confined of 58.5% of bedrock wells and 42.8% of alluvial wells: 93 and 68 wells out of 159 wells, respectively. Even among the bedrock wells, 50 wells (53.7% exhibited characteristics of the unconfined condition, implying significant vulnerability of the aquifer to contaminants from the land surface and shallow depths. It appears to be better approach for deep bedrock aquifers than shallow alluvial aquifers. However, significant portions of the water-level changes remained unclear for categorising aquifer conditions due to disturbances in data continuity. For different aquifer conditions, PCA could show typical pattern and factor scores of principal components. Principal component 1 due to wet-and-dry seasonal changes and water-level response time was dominant covering about 55% of total variances of each aquifer conditions, implying the usefulness of supplementary method of aquifer characterisation. Cross-correlation and time-lag analysis in the water-level responses to precipitations clearly show how the water levels in shallow and deep wells correspond in time scale. No significant differences in time-lags was found between shallow and deep wells. However, clear time-lags were found to be increasing from unconfined to confined conditions: from 1.47 to 2.75 days and from 1.78 to 2.75 days for both shallow alluvial and deep bedrock wells, respectively. In combination of various statistical methods, three types of water-level fluctuation

  12. HIGH ARSENIC CONCENTRATIONS AND ENRICHED SULFUR AND OXYGEN ISOTOPES IN A FRACTURED-BEDROCK GROUND-WATER SYSTEM

    Science.gov (United States)

    Elevated arsenic concentrations are coincident with enriched sulfur and oxygen isotopes of sulfate in bedrock ground water within Kelly's Cove watershed, Northport, Maine, USA. Interpretation of the data is complicated by the lack of correlations between sulfate concentrations an...

  13. Digital and preliminary bedrock geologic map of the Townshend 7.5 x 15 minute quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital Data from VG98-335A Armstrong, T.R., and Ratcliffe, N.M., 1998, Digital and preliminary bedrock geologic map of the Townshend 7.5 x 15 minute quadrangle,...

  14. The effect of wet-dry weathering on the rate of bedrock river channel erosion by saltating gravel

    Science.gov (United States)

    Inoue, Takuya; Yamaguchi, Satomi; Nelson, Jonathan M.

    2017-01-01

    Previous work has shown that the bedrock erosion rate E because of collisions of saltating bedload can be expressed by E = βqb(1-Pc), where qb is the sediment transport rate, Pc is the extent of alluvial cover, and β is the abrasion coefficient. However, the dependence of the abrasion coefficient on the physical characteristics of the bedrock material is poorly known, and in particular, the effects of wet-dry weathering on the saltation-abrasion bedrock incision has not been specifically characterized. Observation suggests that the typical wet-dry cycling of exposed bedrock in river beds gives rise to cracks and voids that are likely to alter the incision rate of the material when subjected to impacts of moving sediment. In this study, flume experiments are performed to develop an understanding of how wet-dry cycling affects the rock tensile strength and the bedrock erosion rate. To represent the physical effects of weathering, boring cores taken from natural bedrock channel are exposed to artificial wet-dry cycles. The experimental results suggest the following: (1) the abrasion coefficient for fresh bedrock is estimated by β = 1.0 × 10− 4σT− 2(d/ksb)0.5, where σT is the tensile strength, d is the diameter of colliding gravel, and ksb is the hydraulic roughness height of bedrock; (2) the tensile strength of the bedrock decreases exponentially as a result of repeated wet-dry cycles, σT/σT0 = exp (-CTNWa0/σT0), where σT0 is the initial tensile strength, Wa0 is the initial normalized rate of water absorption., N is the number of wet-dry cycles, and CT is a constant; (3) the erosion rate of fresh bedrock depends on the inverse of the square of tensile strength, but the erosion rate of weathered bedrock depends on the − 1.5 power of tensile strength.

  15. Cable-suspended Ice and Bedrock Electromechanical Drill: Design and Tests

    Science.gov (United States)

    Wang, Rusheng; Talalay, Pavel; Sun, Youhong; Zheng, Zhichuan; Cao, Pinlu; Zhang, Nan; Chen, Chen; Xu, Huiwen; Xue, Hong; Xue, Jun; Yu, Dahui; Fan, Xiaopeng; Hu, Zhengyi; Yang, Cheng; Gong, Da; Liu, Chunpeng; Han, Junjie; Yu, Chengfeng; Hong, Jialing; Wang, Lili

    2014-05-01

    Directly obtaining the subglacial bedrock samples is one of the most important tasks of Antarctic exploration in the future, which has great significance to research the formation and evolution of the Antarctic ice sheet, research the environment at the junction of the ice and bedrock, and research the geologic structure in Polar Regions. To drill through ice and bedrock, a new modified version of the cable-suspended Ice and Bedrock Electromechanical Drill 'IBED' is designed. IBED drill has modulus construction. The upper part includes four sections: cable termination, slip rings section, antitorque system, electronic pressure chamber. The motor-gear system is differed by rotation speed of the output shaft of the gear-reducer. All modulus contain 3 kW AC3 × 380 V submersible motor. Gear-reducer for drilling in ice lowers the drill bit rotation speed to 100 rpm; gear reducer for subglacial drilling lowers the drill bit rotation speed to 500 rpm. In addition, module for dry core drilling contains vacuum pump for near bottom air reverse circulation instead of liquid-driven pump that is installed into other two variants. The rotation speed of air-driven pump is increased by the gear to 6000 rpm. In modules for drilling with liquid the gear pump is used with capacity of 38-41 L/min and maximal pressure of 0.2 MPa. IBED lower part for drilling in ice consists from two parts: chip chamber for filtration of drilling fluid and collecting chips, and core barrel with the drill bit. The outer/inner diameter of the ice core drill bit is 134/110 mm. Length of the core barrel is 2.5 m. Lower part of the bedrock drill is adapted for coring bedrock and contains standard 2-m length core barrel borrowed from conventional diamond drill string, chip chamber for gravity separation of rock cuttings and dead weights (appr. 200 kg) for increasing of the load on the diamond drill bit. The outer/inner diameters of the diamond bit are 59/41 mm. The IBED drill was tested in order to solve

  16. Joint-bounded crescentic scars formed by subglacial clast-bed contact forces: Implications for bedrock failure beneath glaciers

    Science.gov (United States)

    Krabbendam, M.; Bradwell, T.; Everest, J. D.; Eyles, N.

    2017-08-01

    Glaciers and ice sheets are important agents of bedrock erosion, yet the precise processes of bedrock failure beneath glacier ice are incompletely known. Subglacially formed erosional crescentic markings (crescentic gouges, lunate fractures) on bedrock surfaces occur locally in glaciated areas and comprise a conchoidal fracture dipping down-ice and a steep fracture that faces up-ice. Here we report morphologically distinct crescentic scars that are closely associated with preexisting joints, termed here joint-bounded crescentic scars. These hitherto unreported features are ca. 50-200 mm deep and involve considerably more rock removal than previously described crescentic markings. The joint-bounded crescentic scars were found on abraded rhyolite surfaces recently exposed (clast-bed contact force as it is dragged over the hard (bedrock) bed. As the ice-embedded boulder approaches a preexisting joint in the bedrock, stress concentrations build up in the bed that exceed the intact rock strength, resulting in conchoidal fracturing and detachment of a crescentic wedge-shaped rock fragment. Subsequent removal of the rock fragment probably involves further fracturing or crushing (comminution) under high contact forces. Formation of joint-bounded crescentic scars is favoured by large boulders at the base of the ice, high basal melting rates, and the presence of preexisting subvertical joints in the bedrock bed. We infer that the relative scarcity of crescentic markings in general on deglaciated surfaces shows that fracturing of intact bedrock below ice is difficult, but that preexisting weaknesses such as joints greatly facilitate rock failure. This implies that models of glacial erosion need to take fracture patterns of bedrock into account.

  17. The glacially overdeepened trough of the Salzach Valley, Austria: Bedrock geometry and sedimentary fill of a major Alpine subglacial basin

    Science.gov (United States)

    Pomper, Johannes; Salcher, Bernhard C.; Eichkitz, Christoph; Prasicek, Günther; Lang, Andreas; Lindner, Martin; Götz, Joachim

    2017-10-01

    Overdeepened valleys are unambiguous features of glacially sculpted landscapes. They result from erosion at the bed of the glacier and their size and shape is determined by ice dynamics and the characteristics of the underlying bedrock. Major overdeepened valleys representing vertical bedrock erosion of several hundreds of meters are characteristic features of many trunk valleys in the formerly glaciated parts of the Alpine mountain belt. The thick sedimentary fill usually hinders attempts to unravel bedrock geometry, formation history and fill characteristics. Based on reflection seismic data and core-logs from multiple deep drillings we construct a detailed bedrock model of the Lower Salzach Valley trough, one of the largest overdeepened valleys in the European Alps. The analysed overdeepened structure characterized by a strongly undulating topography. Two reaches of enhanced erosion can be identified and are suggested to be related to variations in bedrock erodibility and a triple glacier confluence. The sedimentary fill shows clear characteristics of rapid infilling and subaqueous fan delta deposits indicate a strong influence of tributary streams. Associated surface lowering of the valley floor had a major impact on tributary stream incision but also on the available ice accumulation area at subsequent glaciations. The extent to which fills of earlier glaciations have been preserved from erosion during the last glacial maximum remains ambiguous and demands further exploration. To our knowledge the presented bedrock model is one of the best defined of any major overdeepened trunk valley.

  18. Climatic controls on mechanical rock strength and channel incision due to bedrock weathering, Kohala Peninsula, Hawaii

    Science.gov (United States)

    Murphy, B. P.; Johnson, J. P.; Gasparini, N. M.; Sklar, L. S.

    2013-12-01

    Orographic precipitation gradients are prevalent in mountainous terrains, and climate-dependent bedrock weathering may play an important role in the incision of bedrock channels and the evolution of landscapes. Kohala Peninsula on the big island of Hawaii presents a unique natural setting for exploring climate sensitivity of landscape erosion, with over an order of magnitude variation in mean annual precipitation, a landscape composed entirely of weatherable basalt, and systematic variations in fluvial incision and resulting topography across the climate gradient. We hypothesize that increases in local mean annual precipitation will promote long-term channel incision rates due to increases in bedrock weathering, but measurements of rock strength within bedrock channels will be greatly influenced by the efficient removal of weathered rock by fluvial erosion. Mechanical properties of bedrock were measured at a total of 13 sites across two watersheds that vary in local mean annual precipitation from 0.27 - 2.25 m/yr. In situ strength measurements were collected using a Schmidt hammer with a pseudo-random sampling method along transects parallel to stream direction and just above the channel thalweg. Tensile strength and elastic moduli were also measured in the laboratory on cores collected from a subset of the same transects. Long-term channel incision rates were independently constrained from the local valley relief and the ages of mapped basalt units that form the relatively unmodified volcanic shield of Kohala. When strength data comes from sites of low long-term incision, we find strong power-law relationships between both rock strength measurements and local mean annual precipitation. However, for sites with high precipitation rate and variable erosion rates, we find significant variability in the rock strength. We interpret this to reflect the removal of weathered rock by erosion. In order to interpret the influence of climate in our dataset, we made a

  19. Interplay between tectonics and topography: Topographic stress controls on bedrock fractures and surface processes

    Science.gov (United States)

    Moon, S.; Perron, J. T.; Martel, S. J.; Holbrook, W. S.; St Clair, J. T.; Singha, K.

    2016-12-01

    The interaction of tectonics, topography, and surface processes influences the evolution of landscapes in tectonically active regions. Though tectonic controls on topography have been extensively studied, the influence of topography on tectonics has been examined less. Theoretical studies have suggested that topography can perturb the tectonic and gravitational stress fields in landscapes, which can influence bedrock fracture patterns and in turn influence erosion. This hypothesis implies that there could be a feedback between topographic stress and landscape evolution such that topographically induced bedrock fractures influence and are influenced by surface processes in evolving topography. In this work, we explore the predictions of a three-dimensional topographic stress model and illustrate how different topographic forms and tectonic settings could influence bedrock fracture patterns. We show that the stress field is most sensitive to topographic perturbations if the most compressive horizontal tectonic stress is oriented perpendicular to the long axis of elongated landforms such as ridges and valleys, and that topographic stress perturbations are most pronounced beneath landforms with higher mean curvatures, such as channel junctions and ridge crests. The shape of a predicted fracture-rich zone in the subsurface depends mainly on the orientation of landforms relative to the most compressive horizontal tectonic stress direction and a dimensionless ratio that expresses the relative magnitudes of topographic stresses associated with tectonics and topographic relief. Variations in this dimensionless ratio can also change the predicted orientations of potential opening-mode fracture planes beneath ridges and valleys. We use these model results to illustrate how topographic perturbations of three-dimensional tectonic and gravitational stresses could influence landscape evolution by altering the rates and spatial heterogeneity of surface processes such as

  20. Plucking in Mixed Alluvial-Bedrock Rivers: The Incipient Motion Problem

    Science.gov (United States)

    Hurst, A. A.; Furbish, D. J.

    2015-12-01

    Bedrock river channel erosion is an important factor in the evolution of landscapes, driving the relief of mountainous drainage basins and setting the lowest erosional positions of terrestrial landscapes. The mechanics behind erosional processes (predominantly plucking and abrasion) in these rivers are only recently being explored in depth. Plucking, the fracture and extraction of jointed blocks, is observationally an order of magnitude more efficient than abrasion, but if a river cannot provide the force necessary to move the plucked block, erosion by plucking cannot proceed. Therefore, incipient motion of blocks starting at rest on a solid surface is an important factor in erosion by plucking. Calculations of forces necessary for incipient motion require values of drag coefficients, which do not exist for bedrock contact geometry. We discovered from experiments on a flume that drag coefficients (CD) are inversely proportional to aspect ratios (RA), defined as the frontal block height to width. We used the relationship with field data from plucked blocks at a stream at Montgomery Bell State Park in Burns, TN, a mixed-alluvial bedrock channel with an actively incising knick zone, to support our theory and experimental data. Sizes of plucked blocks were compared to the velocities needed to move them, and then calculations done for bankfull velocities at the stream at Montgomery Bell to determine if it could attain these velocities. It was discovered that this stream has a bankfull depth-averaged velocity of 1.26 m s-1 and is capable of moving a large range of plucked block sizes. Therefore, erosion of this particular stream is plucking-limited, not transport-limited.

  1. Initial yield to depth relation for water wells drilled into crystalline bedrock - Pinardville quadrangle, New Hampshire

    Science.gov (United States)

    Drew, L.J.; Schuenemeyer, J.H.; Amstrong, T.R.; Sutphin, D.M.

    2001-01-01

    A model is proposed to explain the statistical relations between the mean initial water well yields from eight time increments from 1984 to 1998 for wells drilled into the crystalline bedrock aquifer system in the Pinardville area of southern New Hampshire and the type of bedrock, mean well depth, and mean well elevation. Statistical analyses show that the mean total yield of drilling increments is positively correlated with mean total well depth and mean well elevation. In addition, the mean total well yield varies with rock type from a minimum of 46.9 L/min (12.4 gpm) in the Damon Pond granite to a maximum of 74.5 L/min (19.7 gpm) in the Permian pegmatite and granite unit. Across the eight drilling increments that comprise 211 wells each, the percentages of very low-yield wells (1.9 L/min [0.5 gpm] or less) and high-yield wells (151.4 L/min [40 gpm] or more) increased, and those of intermediate-yield wells decreased. As housing development progressed during the 1984 to 1998 interval, the mean depth of the wells and their elevations increased, and the mix of percentages of the bedrock types drilled changed markedly. The proposed model uses a feed-forward mechanism to explain the interaction between the increasing mean elevation, mean well depth, and percentages of very low-yielding wells and the mean well yield. The increasing percentages of very low-yielding wells through time and the economics of the housing market may control the system that forces the mean well depths, percentages of high-yield wells, and mean well yields to increase. The reason for the increasing percentages of very low-yield wells is uncertain, but the explanation is believed to involve the complex structural geology and tectonic history of the Pinardville quadrangle.

  2. Hazard Ranking Method for Populations Exposed to Arsenic in Private Water Supplies: Relation to Bedrock Geology.

    Science.gov (United States)

    Crabbe, Helen; Fletcher, Tony; Close, Rebecca; Watts, Michael J; Ander, E Louise; Smedley, Pauline L; Verlander, Neville Q; Gregory, Martin; Middleton, Daniel R S; Polya, David A; Studden, Mike; Leonardi, Giovanni S

    2017-12-01

    Approximately one million people in the UK are served by private water supplies (PWS) where main municipal water supply system connection is not practical or where PWS is the preferred option. Chronic exposure to contaminants in PWS may have adverse effects on health. South West England is an area with elevated arsenic concentrations in groundwater and over 9000 domestic dwellings here are supplied by PWS. There remains uncertainty as to the extent of the population exposed to arsenic (As), and the factors predicting such exposure. We describe a hazard assessment model based on simplified geology with the potential to predict exposure to As in PWS. Households with a recorded PWS in Cornwall were recruited to take part in a water sampling programme from 2011 to 2013. Bedrock geologies were aggregated and classified into nine Simplified Bedrock Geological Categories (SBGC), plus a cross-cutting "mineralized" area. PWS were sampled by random selection within SBGCs and some 508 households volunteered for the study. Transformations of the data were explored to estimate the distribution of As concentrations for PWS by SBGC. Using the distribution per SBGC, we predict the proportion of dwellings that would be affected by high concentrations and rank the geologies according to hazard. Within most SBGCs, As concentrations were found to have log-normal distributions. Across these areas, the proportion of dwellings predicted to have drinking water over the prescribed concentration value (PCV) for As ranged from 0% to 20%. From these results, a pilot predictive model was developed calculating the proportion of PWS above the PCV for As and hazard ranking supports local decision making and prioritization. With further development and testing, this can help local authorities predict the number of dwellings that might fail the PCV for As, based on bedrock geology. The model presented here for Cornwall could be applied in areas with similar geologies. Application of the method

  3. Geochemical impacts of groundwater heat pump systems in an urban alluvial aquifer with evaporitic bedrock

    International Nuclear Information System (INIS)

    Garrido Schneider, Eduardo A.; García-Gil, Alejandro; Vázquez-Suñè, Enric; Sánchez-Navarro, José Á.

    2016-01-01

    In the last decade, there has been an extensive use of shallow geothermal exploitations in urban environments. Although the thermal interference between exploitations has been recently studied, there is a lack of knowledge regarding the geochemical impacts of those systems on the aquifers where they are installed. Groundwater flow line scale and well-doublet scale research work has been conducted at city scale to quantify the geochemical interaction of shallow geothermal exploitations with the environment. A comprehensive analysis was conducted on data obtained from a monitoring network specifically designed to control and develop aquifer policies related to thermal management of the aquifer. The geochemical impacts were evaluated from a thermodynamic point of view by means of saturation index (SI) calculations with respect to the different mineral species considered in the system. The results obtained indicate limited geochemical interaction with the urban environment in most of the situations. However, there are some cases where the interaction of the groundwater heat pump installations with the evaporitic bedrock resulted in the total disablement of the exploitation system operation wells. The application of the tool proposed proved to be pragmatic in the evaluation of geochemical impacts. Injection of water into the aquifer can trigger an important bedrock gypsum and halite dissolution process that is partly responsible for scaling in well casing pipes and collapse of the terrain in the vicinity of injection wells. - Highlights: • We studied geochemical impacts of groundwater heat pump systems. • We have sampled a monitoring network in an energetically exploited urban aquifer. • A limited geochemical interaction has been found in most of the exploitations. • Reinjection into the aquifer produces an important bedrock gypsum dissolution. • Scaling in well casing pipes and collapse of the terrain have been observed.

  4. Fractured Epikarst Bedrock as Water Source for Woody Plants in Savanna

    Science.gov (United States)

    Schwinning, S.; Goodsheller, K. R.; Schwartz, B. F.

    2010-12-01

    Study of the soil-vegetation-atmosphere system has been overwhelmingly dominated by systems with deep soils, yet large portions of the world are characterized by shallow soils underlain by fractured bedrock. In these systems, fractured bedrock may provide significant water storage, but we know little about the function of fractured bedrock as a water source for plants. In this study we examined the water use of three co-dominant tree species on the eastern rim of the karstic Edwards Plateau where the soil is extremely rocky, only 20 -30 cm thick, and overlies a well-developed epikarst. We used Granier sap flow sensors to estimate changes in sapflow velocity with the onset of summer drought. Simultaneously, we measured precipitation inputs and drip rates in a shallow cave below the field site. Precipitation, stem and drip water were also periodically sampled for stable isotope analysis to match stem water with potential source waters. The year of the study, 2009, was characterized by extreme drought conditions developing during summer. Sap flow rates began to decline in mid-May for all three species, but there were distinct species differences in the development of water stress: live oak (Quercus fusiformis) was the first to show significant loss of transpiration, reaching minimal sap flow values by early June. Cedar elm (Ulmus crassifolia) reached minimal sap flow values by early July, while Ashe juniper’s (Juniperus ashei) loss of transpiration was very gradual, continuing to decline until early August. The isotope ratios of hydrogen and oxygen in water were not significantly different between species, suggesting that root development and water uptake was similarly constrained for the three species. In summer, all stem water isotope ratios were enriched relative to precipitation, while all drip waters coincided with the local meteoric water line. This suggests that tree water sources were relatively shallow and water draining out of the root zone did not have a

  5. Mapping Depth to Bedrock in a Tropical Pre-Montane Wet Forest in Costa Rica

    Science.gov (United States)

    Oien, R. P.; Burns, J. N.; Arnott, R.; Ackerson, J. P.; Morgan, C.

    2012-12-01

    Accounting for all components of the water balance in a watershed includes an estimate of soil water storage, which in turn depends on the depth to bedrock. The soils in this transitional tropical forest contain large amounts of amorphous material from the saprolitic tuff thus classifying the soils as Andisols. Measuring the depth to bedrock in tropical montane environments is complicated by aspect, elevation, slope, landslides, slumping and other mass wasting events. As part of a larger study, Texas A& M Costa Rica REU aimed to close the water budget for a tropical pre-montane forest, the focus of this study is to generate a map of the depth to saprolitic tuff and topographical information for the purpose of estimating the volume of soil water storage in the Howler Monkey Watershed at Texas A&M University Soltis Center for Research and Education, San Isidro de Peñas Blancas, Costa Rica. A map of the depth to saprolitic tuff was created using 101 hand- augured holes (over 2.63 ha) spatially distributed throughout the watershed. Saprolitic tuff was defined as being 50% of the sample and containing grittiness and cobble sized chunks. To characterize the soils throughout the watershed, soil horizons at three sites were described and 22 cores for particle size. The cores consisted of over 40-55% clay classifying them as clayey or clayey loam. The samples also ranged from 50-73% water content. A map showing the slopes within the watershed also shows the relationship of soil depth above the bedrock within the watershed. The slopes across the watershed vary from 12-65 degrees but only have a 24% correlation with the depth to saprolitic tuff. Results suggest that the depth of the saprolitic tuff is quite sensitive to small scale topographic variability. Soil with such high water content becomes an integral part of the water budget since a significant portion of the water is maintained within the soil. Depth to bedrock provides necessary data to estimate the total volume

  6. Implications Of Fault Damaged Bedrock To Tectonic and Landscape Evolution In Coastal Alaska

    Science.gov (United States)

    Boucher, A.; Koons, P. O.; Roy, S. G.; Birkel, S. D.; Kaluzienski, L. M.; Campbell, S. W.

    2015-12-01

    Bedrock material strength properties heavily impact erosion rates in temperate glacial environments. We focus on the influence of localized tectonic crustal weakening in southeast Alaska on modern glacial erosion rates, thereby quantifying a primary feedback in tectonic/climatic coupling. Southeast Alaska, with its coincident high strain rates, vigorous glacial erosion and rapid sedimentation rates, provides an excellent setting in which to evaluate this interaction. To characterize the relationship between fault damage and glacial incision, we collected data in transects across the strike-slip Fairweather Fault in Yakutat and Disenchantment Bays, in deglaciated valleys below the Mendenhall, Herbert, Ptarmigan, and Lemon Creek Glaciers on the perimeter of the Juneau Icefield, and on deglaciated nunataks on the Echo and Vaughan Lewis Glaciers in the interior of the Juneau Icefield. The mechanical properties of the bedrock are characterized by estimates of fault spacing and material cohesion. In structurally-controlled bedrock valleys exploited by glaciers, fracture spacing may vary by several orders of magnitude across fault damage zones, from more than 10 m to less than 0.1 m. Analysis of active and quiescent fault zones indicate that this variation approximates a power law relationship and correlates with a gradient in cohesive strength varying from greater than 50 MPa to less than 50 kPa between intact bedrock and the core of fault damage zones. The width and orientation of the damage zones is highly variable and we have chosen our field sites to sample zones of very large total displacement, up to kilometers along the Fairweather Fault, and substantially smaller displacements, down to centimeters for the Juneau Icefield locales. Using a Cordilleran Ice sheet model to extend our modern observations into last glacial maximum conditions, we predict both erosion rates and sediment provenance for a material strength pattern influenced by tectonically induced fault

  7. Mise-a-la-masse method in structure investigations of crystalline bedrock; Latauspotentiaalimenetelmae kiteisen kallion rakennetutkimuksissa

    Energy Technology Data Exchange (ETDEWEB)

    Paananen, M.

    1997-12-31

    In the work, the experience and results obtained in applying the mise-a-la-masse method in bedrock investigations for high- level nuclear waste disposal are presented. On the basis of extensive numerical modelling and qualitative examination, the following items are discussed: how the field measurements should be carried out, in which form the results should be presented and how a galvanic connection formed be a fracture zone can be observed from the results. This examination is valid for hole- to-surface (or vice versa) and crosshole measurements. 51 refs. Nuclear Waste Disposal Research.

  8. Ground source energy in crystalline bedrock - increased energy extraction by using hydraulic fracturing in boreholes

    Energy Technology Data Exchange (ETDEWEB)

    Ramstad, Randi Kalstad

    2004-11-01

    The use of improved equipment and methodology can result in considerable reductions in the drilling costs for medium- to large sized ground source heat pump system in crystalline bedrock. The main point has been to use special techniques within hydraulic fracturing to create a larger heat exchange area in the bedrock, and thus a greater energy extraction per borehole. The energy extraction is based on circulating groundwater. Stimulation with hydraulic fracturing is a well known technique in order to improve borehole yields for drinking water-, oil-, and geothermal purposes. A procedure for injection of propping agents in selected borehole sections, and custom-made equipment for hydraulic fracturing in crystalline bedrock, a double packer, have been developed in this study. The propping agents are likely to ensure a permanent improvement of the hydraulic conductivity in a long-run perspective. In addition to a pre-test, a comprehensive test programme has been performed at each of the two pilot plants at Bryn and at the former property of Energiselskapet Asker og Baerum (EAB) in Baerum municipality outside Oslo, Norway. A total of 125 stimulations with hydraulic fracturing using water-only and hydraulic fracturing with injection of sand have been performed in 9 boreholes. Test pumping and geophysical logging (temperature, electrical conductivity, gamma radiation, optical televiewer and flow measurements) have been carried out in order to document the effect of the hydraulic fracturing. The pilot plants at Bryn and EAB, where the ground source heat pump systems are based on circulating groundwater, have demonstrated the short-period energy extraction, limitations and opportunities of the concept for hydraulic fracturing and increased energy extraction in different geological and hydrogeological areas. The bedrock at Bryn and EAB is characterized as a low-metamorphic sandstone and a nodular limestone, respectively. At Bryn, the five boreholes were organised with a

  9. Controls on sediment cover in bedrock-alluvial channels of the Henry Mountains, Utah

    Science.gov (United States)

    Hodge, R. A.; Yager, E.; Johnson, J. P.; Tranmer, A.

    2017-12-01

    The location and extent of sediment cover in bedrock-alluvial channels influences sediment transport rates, channel incision and instream ecology. However, factors affecting sediment cover and how it responds to changes in relative sediment supply have rarely been quantitatively evaluated in field settings. Using field surveys and SFM analysis of channel reach topography, we quantified sediment cover and channel properties including slope, width, grain size distributions, and bedrock and alluvial roughness in North Wash and Chelada Creek in the Henry Mountains, Utah. Along reaches where upstream sediment supply does not appear to be restricted, we find that the fraction of local bedrock exposure increases as a function of local relative transport capacity . In a downstream section of Chelada Creek, decadal-scale sediment supply has been restricted by an upstream culvert that has caused a backwater effect and corresponding upstream deposition. In this section, alluvial cover is uncorrelated with local stream power. To test the impact of relative sediment supply on sediment cover, a 1D sediment transport model was used to predict the equilibrium sediment cover in Chelada Creek under varying flow and sediment supply conditions. Sediment transport in each model section was predicted using the partial cover model of Johnson (2015), which accounts for differences in bedrock and alluvial roughness on critical shear stress and flow resistance. Model runs in which sediment supply was approximately equal to mean transport capacity produced a pattern of sediment cover which best matched the field observations upstream of the culvert. However, runs where sediment supply was under-capacity produced the pattern most similar to field observations downstream of the culvert, consistent with our field-based interpretations. Model results were insensitive to initial sediment cover, and equilibrium was relatively quickly reached, suggesting that the channel is responsive to changes in

  10. The influence of subsurface porosity and bedrock composition on ecosystem productivity and drought resilience in the Sierra Nevada Batholith, California

    Science.gov (United States)

    Riebe, C. S.; Callahan, R. P.; Goulden, M.; Pasquet, S.; Flinchum, B. A.; Taylor, N. J.; Holbrook, W. S.

    2017-12-01

    The availability of water and nutrients in soil and weathered rock influences the distribution of Earth's terrestrial life and regulates ecosystem vulnerability to land use and climate change. We explored these relationships by combining geochemical and geophysical measurements at three mid-elevation sites in the Sierra Nevada, California. Forest cover correlates strongly with bedrock composition across the sites, implying strong lithologic control on the ecosystem. We evaluated two hypotheses about bedrock-ecosystem connections: 1) that bedrock composition influences vegetation by moderating plant-essential nutrient supply; and 2) that bedrock composition influences the degree of subsurface weathering, which influences vegetation by controlling subsurface water-storage capacity. To quantify subsurface water-holding capacity, we used seismic refraction surveys to infer gradients in P and S-wave velocity structure, which reveal variations in porosity when coupled together in a Hertz-Mindlin rock-physics model. We combined the geophysical data on porosity with bedrock bulk geochemistry measured in previous work to evaluate the influence of water-holding capacity and nutrient supply on ecosystem productivity, which we quantified using remote sensing. Our results show that more than 80% of the variance in ecosystem productivity can be explained by differences in bedrock phosphorus concentration and subsurface porosity, with phosphorus content being the dominant explanatory variable. This suggests that bedrock composition exerts a strong bottom-up control on ecosystem productivity through its influence on nutrient supply and weathering susceptibility, which in turn influences porosity. We show that vegetation vulnerability to drought stress and mortality can be explained in part by variations in subsurface water-holding capacity and rock-derived nutrient supply.

  11. Microbes in crystalline bedrock. Assimilation of CO2 and introduced organic compounds by bacterial populations in groundwater from deep crystalline bedrock at Laxemar and Stripa

    International Nuclear Information System (INIS)

    Pedersen, K.; Ekendahl, S.; Arlinger, J.

    1991-12-01

    The assimilation of CO 2 and of introduced organic compounds by bacterial populations in deep groundwater from fractured crystalline bedrock has been studied. Three depth horizons of the subvertical boreholes KLZ01 at Laxemar in southeastern Sweden, 830-841 m, 910-921 m and 999-1078 m, and V2 in the Stripa mine, 799-807m 812-820 m and 970-1240 m were sampled. The salinity profile of the KLX01 borehole is homogeneous and the groundwater had the following physico-chemical characteristics: pH values of 8.2, 8.4 and 8.5; Eh values of 270, no data and -220 mV; sulphide: 2.3, 11.0 and 5.6 μM; CO 3 2- : 104, 98 and 190 μM; CH 4 : 26, 27 and 31 μl/l and N 2 : 47, 25 and 18 ml/l, respectively. The groundwater in V2 in Stripa were obtained from fracture systems without close hydraulic connections and had the following physico-chemical characteristics: pH values of 9.5, 9.4 and 10.2; Eh values of +205, +199 and -3 mV; sulphide: 0, 106 and 233 μM; CO 3 2- : 50, 57 and 158 μM; CH 4 : 245, 170 and 290 μl/l and N 2 : 25, 31 and 25 ml/l, respectively. Biofilm reactors with hydrophilic glass surfaces were connected to the flowing groundwaters from each of the 3 depths with flow rates of approximately 3x10 -3 m sec -1 over 19 days in Laxemar and 27 to 161 days in Stripa. There were between 0.15 to 0.68 x 10 5 unattached bacteria ml -1 groundwater and 0.94 to 1.2 x 10 5 attached bacteria cm -2 on the surface in Laxemar and from 1.6 x 10 3 up to 3.2 x 10 5 bacteria ml -1 groundwater and from 2.4 x 10 5 up to 1.1 x 10 7 bacteria cm -2 of colonized test surfaces in Stripa. Assuming a mean channel width of 0.1 mm, our results imply that there would be from 10 3 up to 10 6 more attached than unattached bacteria in a water conducting channel in crystalline bedrock. (54 refs., 23 figs., 10 tabs.) (au)

  12. Vertical and horizontal bedrock displacements near Jakobshavn Isbræ due to glacial ice mass loss

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Wahr, John; Liu, Lin

    2011-01-01

    We analyze GPS data from four continuous Global Positioning System (GPS) receivers located between 5 and 150 km from the glacier Jakobshavn Isbræ, West Greenland. The GPS stations were established on bedrock to determine the vertical and horizontal crustal motion due to the unloading of ice from ...... are much larger closer to Jakobshavn than further away, and are consistent with rates inferred using the ATM-based glacier thinning model, shows that GPS measurements of crustal motion are a potentially useful method for assessing ice-mass change models.......We analyze GPS data from four continuous Global Positioning System (GPS) receivers located between 5 and 150 km from the glacier Jakobshavn Isbræ, West Greenland. The GPS stations were established on bedrock to determine the vertical and horizontal crustal motion due to the unloading of ice from...... thins and loses mass. The observed rates are consistent with a glacier thinning model based on repeat altimeter surveys from NASA’s Airborne Topographic Mapper (ATM), which shows that Jakobshavn lost mass at an average rate of 22 +- 2 km3/yr between 2006 and 2009. The fact that the GPS uplift rates...

  13. Modelling of Radionuclide Transport by Groundwater Motion in Fractured Bedrock for Performance Assessment Purposes

    International Nuclear Information System (INIS)

    Woerman, Anders; Shulan Xu

    2003-10-01

    Field data of physical properties in heterogeneous crystalline bedrock, like fracture zones, fracture connectivity, matrix porosity and fracture aperture, is associated with uncertainty that can have a significant impact on the analysis of solute transport in fractured rock. The purpose of this study is to develop a performance assessment (PA) model for analyses of radionuclide transport in the geosphere, in which the model takes into account both the effect of heterogeneities of hydrological and geochemical rock properties. By using a travel time description of radionuclide transport in rock fractures, we decompose the transport problem into a one-dimensional mass transfer problem along a distribution of transport pathways and a multi-dimensional flow problem in the fractured bedrock. The hydraulic/flow problem is solved based on a statistical discrete-fracture model (DFM) that represents the network of fractures around the repository and in the surrounding geosphere. A Monte Carlo technique reflects the fact that the representation of the fracture network is uncertain. If the flow residence time PDF exhibits multiple peaks or in another way shows a more erratic hydraulic response on the network scale, the three-dimensional travel time approach is superior to a one-dimensional transport modeling. Examples taken from SITE 94, a study performed by the Swedish Nuclear Power Inspectorate, showed that such cases can be found in safety assessments based on site data. The solute transport is formulated based on partial, differential equations and perturbations (random spatial variability in bedrock properties) are introduced in the coefficients to reflect an uncertainty of the exact appearance of the bedrock associated with the discrete data collection. The combined approach for water flow and solute transport, thereby, recognises an uncertainty in our knowledge in both 1) bedrock properties along individual pathways and 2) the distribution of pathways. Solutions to the

  14. A new multiple spatial resolution estimate of the bedrock elevation of the Greenland ice sheet.

    Science.gov (United States)

    Griggs, Jennifer; Bamber, Jonathan; Plummer, Joel; Gogineni, Sivaprasad; Rignot, Eric

    2010-05-01

    Gridded bedrock elevation for the Greenland ice sheet has previously been determined with 5 km postings. The true resolution of the data set was, in places, however, considerably coarser than this due to the across-track spacing of flight lines. Errors were estimated to be on the order of a few percent in the centre of the ice sheet but increasing markedly in relative magnitude near the margins, where, for numerical modelling, accurate thickness is particularly critical. We use new airborne and satellite estimates of ice thickness and surface elevation to determine the bed topography for the whole of Greenland. In particular, the University of Kansas have in recent years, flown an airborne ice-penetrating radar system with close flightline spacing over several key outlet glacier systems. This allows us to produce a multi-resolution bedrock elevation dataset with the high spatial resolution needed for ice dynamic modelling over these key outlet glaciers and coarser resolution over the more sparsely sampled interior. Airborne ice thickness and elevation from CReSIS obtained between 1993 and 2009 are combined with JPL, DONNEES data covering the marginal areas along the south west coast from 2009. Data collected in the 1970's by the Technical University of Denmark were also used in interior areas with sparse coverage from other sources. Marginal elevation data from the ICESat laser altimeter were used to help constrain the ice thickness and bed topography close to the ice sheet margin where, typically, the terrestrial observations have poor sampling between flight tracks.

  15. Increased forest ecosystem carbon and nitrogen storage from nitrogen rich bedrock.

    Science.gov (United States)

    Morford, Scott L; Houlton, Benjamin Z; Dahlgren, Randy A

    2011-08-31

    Nitrogen (N) limits the productivity of many ecosystems worldwide, thereby restricting the ability of terrestrial ecosystems to offset the effects of rising atmospheric CO(2) emissions naturally. Understanding input pathways of bioavailable N is therefore paramount for predicting carbon (C) storage on land, particularly in temperate and boreal forests. Paradigms of nutrient cycling and limitation posit that new N enters terrestrial ecosystems solely from the atmosphere. Here we show that bedrock comprises a hitherto overlooked source of ecologically available N to forests. We report that the N content of soils and forest foliage on N-rich metasedimentary rocks (350-950 mg N kg(-1)) is elevated by more than 50% compared with similar temperate forest sites underlain by N-poor igneous parent material (30-70 mg N kg(-1)). Natural abundance N isotopes attribute this difference to rock-derived N: (15)N/(14)N values for rock, soils and plants are indistinguishable in sites underlain by N-rich lithology, in marked contrast to sites on N-poor substrates. Furthermore, forests associated with N-rich parent material contain on average 42% more carbon in above-ground tree biomass and 60% more carbon in the upper 30 cm of the soil than similar sites underlain by N-poor rocks. Our results raise the possibility that bedrock N input may represent an important and overlooked component of ecosystem N and C cycling elsewhere.

  16. Bedrock geologic map of the Yucca Mountain area, Nye County, Nevada

    International Nuclear Information System (INIS)

    Day, W.C.; Potter, C.J.; Sweetkind, D.S.; Fridrich, C.J.; Dickerson, R.P.; San Juan, C.A.; Drake, R.M. II

    1998-01-01

    Yucca Mountain, Nye County, Nevada, has been identified as a potential site for underground storage of high-level radioactive nuclear waste. Detailed bedrock geologic maps form an integral part of the site characterization program by providing the fundamental framework for research into the geologic hazards and hydrologic behavior of the mountain. This bedrock geologic map provides the geologic framework and structural setting for the area in and adjacent to the site of the potential repository. The study area comprises the northern and central parts of Yucca Mountain, located on the southern flank of the Timber Mountain-Oasis Valley caldera complex, which was the source for many of the volcanic units in the area. The Timber Mountain-Oasis Valley caldera complex is part of the Miocene southwestern Nevada volcanic field, which is within the Walker Lane belt. This tectonic belt is a northwest-striking megastructure lying between the more active Inyo-Mono and Basin-and-Range subsections of the southwestern Great Basin

  17. Large bedrock slope failures in a British Columbia, Canada fjord: first documented submarine sackungen

    Science.gov (United States)

    Conway, Kim W.; Vaughn Barrie, J.

    2018-01-01

    Very large (>60×106 m3) sackungen or deep-seated gravitational slope deformations occur below sea level along a steep fjord wall in central Douglas Channel, British Columbia. The massive bedrock blocks were mobile between 13 and 11.5 thousand radiocarbon years BP (15,800 and 13,400 BP) immediately following deglaciation. Deformation of fjord sediments is apparent in sedimentary units overlying and adjacent to the blocks. Faults bound the edges of each block, cutting the glacial section but not the Holocene sediments. Retrogressive slides, small inset landslides as well as incipient and older slides are found on and around the large failure blocks. Lineations, fractures and faults parallel the coastline of Douglas Channel along the shoreline of the study area. Topographic data onshore indicate that faults and joints demarcate discrete rhomboid-shaped blocks which controlled the form, size and location of the sackungen. The described submarine sackungen share characteristic geomorphic features with many montane occurrences, such as uphill-facing scarps, foliated bedrock composition, largely vertical dislocation and a deglacial timing of development.

  18. Geochemistry of the ground waters of the bedrock on Haestholmen, Loviisa

    International Nuclear Information System (INIS)

    Hyyppae, J.

    1984-03-01

    Haestholmen is an island in the Gulf of Finland about 80 km east of Helsinki and 10 km southeast of the c entre of the town of Loviisa. Because of its geological location at the western margin of the Viipuri rapakivi massif its bedrock is composed of various types of rapakivi. The geochemistry of the ground waters in the Haestholmen area was studied by taking samples from seven 200-m-deep holes. Electric conductivity, contents of fluoride, lead, zinc, cadmium copper and chromium were determined in samples from different layers of ground water. The present ground-water conditions in the bedrock of Haestholmen are due to the rise of the islands at a rate of close to 30 cm in 100 years, in other words, the highest places on the island were at about sea level around 5000 years ago. The layer of fresh ground water will continue to expand laterally and vertically over the next years, when the land will rise by about 1.5 m if the climate remains more or less the same as it is at present

  19. Radio Echo Sounding (RES investigations at Talos Dome (East Antarctica: bedrock topography and ice thickness

    Directory of Open Access Journals (Sweden)

    I. E. Tabacco

    2003-06-01

    Full Text Available Radio echo sounding measurements were collected during two Antarctic expeditions to determine the ice thickness and the sub-glacial morphology of Talos Dome in the region around 72°48'S; 159°06'E (about 6400 km2 on the edge of the East Antarctic plateau adjacent to Victoria Land in the western Ross Sea sector. The increasing interest in this region is due to the fact that in this area the ice accumulation is higher than in other sites in East Antarctica. Because of this, Talos Dome could be a new site for a project of a deep ice core drilling to obtain information on climate changes near the coast of Antarctica. In this frame, the knowledge of the bedrock topography is of great importance to choose the best location for the drilling site. In this paper, airborne radio echo sounding results from two Antarctic expeditions (1997 and 1999 are presented. Bedrock topography in bi- and three-dimensions for the Talos Dome region are discussed.

  20. Impacts of groundwater metal loads from bedrock fractures on water quality of a mountain stream.

    Science.gov (United States)

    Caruso, Brian S; Dawson, Helen E

    2009-06-01

    Acid mine drainage and metal loads from hardrock mines to surface waters is a significant problem in the western USA and many parts of the world. Mines often occur in mountain environments with fractured bedrock aquifers that serve as pathways for metals transport to streams. This study evaluates impacts from current and potential future groundwater metal (Cd, Cu, and Zn) loads from fractures underlying the Gilt Edge Mine, South Dakota, on concentrations in Strawberry Creek using existing flow and water quality data and simple mixing/dilution mass balance models. Results showed that metal loads from bedrock fractures to the creek currently contribute water quality is achieved upstream in Strawberry Creek, fracture metal loads would be water quality standards exceedances once groundwater with elevated metals concentrations in the aquifer matrix migrates to the fractures and discharges to the stream. Potential future metal loads from an upstream fracture would contribute a small proportion of the total load relative to current loads in the stream. Cd has the highest stream concentrations relative to standards. Even if all stream water was treated to remove 90% of the Cd, the standard would still not be achieved. At a fracture farther downstream, the Cd standard can only be met if the upstream water is treated achieving a 90% reduction in Cd concentrations and the median stream flow is maintained.

  1. Comparison of dialysis membrane diffusion samplers and two purging methods in bedrock wells

    Science.gov (United States)

    Imbrigiotta, T.E.; Ehlke, T.A.; Lacombe, P.J.; Dale, J.M.; ,

    2002-01-01

    Collection of ground-water samples from bedrock wells using low-flow purging techniques is problematic because of the random spacing, variable hydraulic conductivity, and variable contamination of contributing fractures in each well's open interval. To test alternatives to this purging method, a field comparison of three ground-water-sampling techniques was conducted on wells in fractured bedrock at a site contaminated primarily with volatile organic compounds. Constituent concentrations in samples collected with a diffusion sampler constructed from dialysis membrane material were compared to those in samples collected from the same wells with a standard low-flow purging technique and a hybrid (high-flow/low-flow) purging technique. Concentrations of trichloroethene, cis-1,2-dichloroethene, vinyl chloride, calcium, chloride, and alkalinity agreed well among samples collected with all three techniques in 9 of the 10 wells tested. Iron concentrations varied more than those of the other parameters, but their pattern of variation was not consistent. Overall, the results of nonparametric analysis of variance testing on the nine wells sampled twice showed no statistically significant difference at the 95-percent confidence level among the concentrations of volatile organic compounds or inorganic constituents recovered by use of any of the three sampling techniques.

  2. Granitic boulder erosion caused by chaparral wildfire: Implications for cosmogenic radionuclide dating of bedrock surfaces

    Science.gov (United States)

    Kendrick, Katherine J.; Camille Partin,; Graham, Robert C.

    2016-01-01

    Rock surface erosion by wildfire is significant and widespread but has not been quantified in southern California or for chaparral ecosystems. Quantifying the surface erosion of bedrock outcrops and boulders is critical for determination of age using cosmogenic radionuclide techniques, as even modest surface erosion removes the accumulation of the cosmogenic radionuclides and causes significant underestimate of age. This study documents the effects on three large granitic boulders following the Esperanza Fire of 2006 in southern California. Spalled rock fragments were quantified by measuring the removed rock volume from each measured boulder. Between 7% and 55% of the total surface area of the boulders spalled in this single fire. The volume of spalled material, when normalized across the entire surface area, represents a mean surface lowering of 0.7–12.3 mm. Spalled material was thicker on the flanks of the boulders, and the height of the fire effects significantly exceeded the height of the vegetation prior to the wildfire. Surface erosion of boulders and bedrock outcrops as a result of wildfire spalling results in fresh surfaces that appear unaffected by chemical weathering. Such surfaces may be preferentially selected by researchers for cosmogenic surface dating because of their fresh appearance, leading to an underestimate of age.

  3. Bedrock geologic map of the Yucca Mountain area, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Day, W.C.; Potter, C.J.; Sweetkind, D.S.; Fridrich, C.J. [Geological Survey, Denver, CO (US); Dickerson, R.P.; San Juan, C.A.; Drake, R.M. II [Pacific Western Technologies, Inc., Denver, CO (US)

    1998-11-01

    Yucca Mountain, Nye County, Nevada, has been identified as a potential site for underground storage of high-level radioactive nuclear waste. Detailed bedrock geologic maps form an integral part of the site characterization program by providing the fundamental framework for research into the geologic hazards and hydrologic behavior of the mountain. This bedrock geologic map provides the geologic framework and structural setting for the area in and adjacent to the site of the potential repository. The study area comprises the northern and central parts of Yucca Mountain, located on the southern flank of the Timber Mountain-Oasis Valley caldera complex, which was the source for many of the volcanic units in the area. The Timber Mountain-Oasis Valley caldera complex is part of the Miocene southwestern Nevada volcanic field, which is within the Walker Lane belt. This tectonic belt is a northwest-striking megastructure lying between the more active Inyo-Mono and Basin-and-Range subsections o f the southwestern Great Basin.

  4. Water flow in bedrock; estimation of influence of transmissive shaft and borehole

    International Nuclear Information System (INIS)

    Andersson, L.; Neretnieks, J.; Rasmuson, A.

    1983-01-01

    The bedrock, a system of large and small fractures that permit water transport through the rock mass. The water content of the bedrock can, under varying hydrostatic pressure conditions, give rise to different flow patterns via boreholes or shafts drilled through the rock. A case is dealt with where a borehole connects a low point in the terrain with a point in the repository where the hydrostatic pressure is higher than at the mouth of the borehole. The situation may be conceived as having arisen when the area was investigated and a hole was drilled at an angle down from the valley to a point below the high point in the area. If the borehole is not sealed, an artesian well may be created. The conductivity used, 2 times 10- 9 m/s, presumes that the repository has been emplaced in average quality rock at this depth. In reality, the repository site will be selected where the rock is better than average. In reality, a shaft - even if it is imperfectly backfilled - or a borehole exerts a flow resistance that reduces the available pressure difference at a depth of 500 m. Taken together, these factors indicate that approx. 5 m 3 /(year, 5 m) is the water flow that can be expected to emerge from the repository through a shaft or a borehole. Only this flow can have been contaminated with escaping substances from the repository area. Water that flows in from other parts of the hole dilutes this flow considerably. (G.B.)

  5. Parameterization and quantification of recharge in crystalline fractured bedrocks in Galicia-Costa (NW Spain

    Directory of Open Access Journals (Sweden)

    J. R. Raposo

    2012-06-01

    Full Text Available Quantifying groundwater recharge in crystalline rocks presents great difficulties due to the high heterogeneity of the underground medium (mainly, due to heterogeneity in fracture network, which determines hydraulic parameters of the bedrock like hydraulic conductivity or effective porosity. Traditionally these rocks have been considered to have very low permeability, and their groundwater resources have usually been neglected; however, they can be of local importance when the bedrock presents a net of well-developed fractures. The current European Water Framework Directive requires an efficient management of all groundwater resources; this begins with a proper knowledge of the aquifer and accurate recharge estimation. In this study, an assessment of groundwater resources in the Spanish hydrologic district of Galicia-Costa, dominated by granitic and metasedimentary rocks, was carried out. A water-balance modeling approach was used for estimating recharge rates in nine pilot catchments representatives of both geologic materials. These results were cross-validated with an independent technique, i.e. the chloride mass balance (CMB. A relation among groundwater recharge and annual precipitation according to two different logistic curves was found for both granites and metasedimentary rocks, thus allowing the parameterization of recharge by means of only a few hydrogeological parameters. Total groundwater resources in Galicia-Costa were estimated to be 4427 hm3 yr−1. An analysis of spatial and temporal variability of recharge was also carried out.

  6. Final disposal of spent nuclear fuel in Finnish bedrock. Olkiluoto site report

    International Nuclear Information System (INIS)

    Anttila, P.; Ahokas, H.; Front, K.

    1999-06-01

    Posiva Oy is studying the Finnish bedrock for the geological disposal of spent nuclear fuel. The study is based on the site selection research programme started originally in 1983. The programme is in accordance with the decision in principle by the Council of State in 1983 and aims at the selection of one site in 2000. Four sites, Haestholmen in Loviisa, Kivetty in Aeaenekoski, Olkiluoto in Eurajoki and Romuvaara in Kuhmo, have been studied in detail. This report summarises the results of the site investigations carried out at Olkiluoto. The bedrock of the Olkiluoto site consists of Svecofennian metasediments and platonic rocks, 1800-1900 million years in age. Migmatitic mica gneiss is the most abundant rock type, and is intruded by foliated tonalites and granodiorites and massive coarse-grained granites and pegmatites. Five successive plastic deformation phases have been defined. In total, 30 bedrock structures (R-structures) have been modelled at the site. Most of these represent steeply dipping fracture zones, but several sub-horizontal zones, gently dipping to the SE, have also been identified. The rock mass between the fracture zones represents what is termed 'intact rock', which is typically hard, unweathered and sparsely fractured. The R-structures are generally hydraulically more conductive than the intact rock and their mean transmissivity is 3 x 10 -7 m 2 /s. The corresponding mean of the hydraulic conductivity values for the intact rock measured using a 2 m packer interval, is 8 x 10 -13 m/s, if a lognormal distribution for all measured values is assumed. A clear decrease in hydraulic conductivity with depth has been found for the intact rock, and there seems to be a parallel decrease in the transmissivity of structures. In addition, the hydraulically conductive fractures seem to be more frequent and their transmissivities higher in the uppermost 100 - 200 m of the bedrock than at greater depths. The groundwater chemistry reflects the postglacial

  7. Final disposal of spent nuclear fuel in Finnish bedrock - Kivetty site report

    Energy Technology Data Exchange (ETDEWEB)

    Anttila, P. [Fortum Engineering Oy, Vantaa (Finland); Ahokas, H.; Front, K. [Fintact Oy (Finland)] [and others

    1999-06-01

    Posiva Oy is studying the Finnish bedrock for the geological disposal of spent nuclear fuel. The study is based on the site selection research programme started originally in 1983. The programme is in accordance with the decision in principle by the Council of State in 1983 and aims at the selection of one site in 2000. Four sites, Haestholmen in Loviisa, Kivetty in Aeaenekoski, Olkiluoto in Eurajoki and Romuvaara in Kuhmo, have been studied in detail. This report summarises the results of the site investigations carried out at Kivetty. The bedrock of Kivetty belongs to the large Svecofennian granitoid complex of central Finland, about 1880 million years in age. The most common rock type is porphyritic granodiorite, which is cut by younger medium-grained granodiorite and porphyritic or even-grained granite. Minor bodies of gabbro, older than the porphyritic granodiorite, are also present. The granitoids show evidence of two deformation phases. Altogether 29 bedrock 'structures' (R-structures) have been modelled at the investigation site, most of them representing steeply dipping fracture zones. The rock mass between the fracture zones represents what is termed 'intact rock', which is typically hard, unweathered and sparsely fractured. The R-structures are generally hydraulically more conductive than the intact rock and their mean transmissivity is 1.3-10{sup -6} m{sup 2}/s. The corresponding mean of the hydraulic conductivity values for the intact rock, measured using a 2 m packer interval is 4*10{sup -11} m{sup 2}/s, if a lognormal distribution for all measured values is assumed. A clear decrease in hydraulic conductivity with depth has been found for the intact rock, and there seems to be a parallel decrease in the transmissivity of structures. In addition, the hydraulically conductive fractures seem to be more frequent and their transmissivities higher in the uppermost 100 - 200 m of the bedrock than at greater depths. The groundwater of

  8. Final disposal of spent nuclear fuel in Finnish bedrock. Haestholmen site report

    Energy Technology Data Exchange (ETDEWEB)

    Anttila, P. [Fortum Engineering Oy, Vantaa (Finland); Ahokas, H. [Fintact Oy, Helsinki (Finland); Front, K. [VTT Communities and Infrastructure, Espoo (Finland)

    1999-06-01

    Posiva Oy is studying the Finnish bedrock for the geological disposal of spent nuclear fuel. The study is based on the site selection research programme started originally in 1983. The programme is in accordance with the decision in principle by the Council of State in 1983 and aims at the selection of one site in 2000. Four sites, Haestholmen in Loviisa, Kivetty in Aeaenekoski, Olkiluoto in Eurajoki and Romuvaara in Kuhmo, have been studied in detail. This report summarises the results of the site investigations carried out at Haestholmen. The Haestholmen area is located within the anorogenic Wiborg rapakivi granite batholith, about 1630 million years in age, representing one of the youngest rock formations in Finland. Wiborgite, pyterlite, porphyritic rapakivi granite and even-grained rapakivi granite are the rock types present. 25 bedrock structures have been modelled at the site. Most of them are steeply-dipping fracture zones trending NW-SE and NE-SW, but several sub-horizontal zones, mainly dipping to the N-NE and the SW, are also present. The rock mass between the fracture zones represents what is termed `intact rock`, which is typically hard, unweathered and sparsely fractured. The bedrock structures are generally hydraulically more conductive than the intact rock and their mean transmissivity is 8 x 10{sup -6} m{sup 2}/s or 1.3 x 10{sup -6} m{sup 2}/s, depending on how structures are defined. The corresponding mean of the hydraulic conductivity values measured for the intact rock using a 2 m packer interval is 1 x 10{sup -12} m/s, if a lognormal distribution for all measured values is assumed. A clear decrease in hydraulic conductivity with depth has been found in the intact rock. In addition, the hydraulically conductive fractures seem to be more frequent and their transmissivities higher in the uppermost 100-200 m of the bedrock than at greater depths. The groundwater chemistry reflects the post-glacial history of the island of Haestholmen, which rose

  9. Final disposal of spent nuclear fuel in Finnish bedrock. Olkiluoto site report

    Energy Technology Data Exchange (ETDEWEB)

    Anttila, P. [Fortum Engineering Oy, Vantaa (Finland); Ahokas, H. [Fintact Oy, Helsinki (Finland); Front, K. [VTT Communication and Infrastructure, Espoo (Finland)] [and others

    1999-06-01

    Posiva Oy is studying the Finnish bedrock for the geological disposal of spent nuclear fuel. The study is based on the site selection research programme started originally in 1983. The programme is in accordance with the decision in principle by the Council of State in 1983 and aims at the selection of one site in 2000. Four sites, Haestholmen in Loviisa, Kivetty in Aeaenekoski, Olkiluoto in Eurajoki and Romuvaara in Kuhmo, have been studied in detail. This report summarises the results of the site investigations carried out at Olkiluoto. The bedrock of the Olkiluoto site consists of Svecofennian metasediments and platonic rocks, 1800-1900 million years in age. Migmatitic mica gneiss is the most abundant rock type, and is intruded by foliated tonalites and granodiorites and massive coarse-grained granites and pegmatites. Five successive plastic deformation phases have been defined. In total, 30 bedrock structures (R-structures) have been modelled at the site. Most of these represent steeply dipping fracture zones, but several sub-horizontal zones, gently dipping to the SE, have also been identified. The rock mass between the fracture zones represents what is termed `intact rock`, which is typically hard, unweathered and sparsely fractured. The R-structures are generally hydraulically more conductive than the intact rock and their mean transmissivity is 3 x 10{sup -7} m{sup 2}/s. The corresponding mean of the hydraulic conductivity values for the intact rock measured using a 2 m packer interval, is 8 x 10{sup -13} m/s, if a lognormal distribution for all measured values is assumed. A clear decrease in hydraulic conductivity with depth has been found for the intact rock, and there seems to be a parallel decrease in the transmissivity of structures. In addition, the hydraulically conductive fractures seem to be more frequent and their transmissivities higher in the uppermost 100 - 200 m of the bedrock than at greater depths. The groundwater chemistry reflects the

  10. Quaternary sediment thickness and bedrock topography of the glaciated United States east of the Rocky Mountains

    Science.gov (United States)

    Soller, David R.; Garrity, Christopher P.

    2018-01-26

    Beginning roughly 2.6 million years ago, global climate entered a cooling phase known as the Pleistocene Epoch. As snow in northern latitudes compacted into ice several kilometers thick, it flowed as glaciers southward across the North American continent. These glaciers extended across the northern United States, dramatically altering the landscape they covered. East of the Rocky Mountains, the ice coalesced into continental glaciers (called the Laurentide Ice Sheet) that at times blanketed much of the north-central and northeastern United States. To the west of the Laurentide Ice Sheet, glaciers formed in the mountains of western Canada and the United States and coalesced into the Cordilleran ice sheet; this relatively smaller ice mass extended into the conterminous United States in the northernmost areas of western Montana, Idaho, and Washington. Throughout the Pleistocene, landscape alteration occurred by (1) glacial erosion of the rocks and sediments; (2) redeposition of the eroded earth materials in a form substantially different from their source rocks, in terms of texture and overall character; and (3) disruption of preexisting drainage patterns by the newly deposited sediments. In many cases, pre-glacial drainage systems (including, for example, the Mississippi River) were rerouted because their older drainage courses became blocked with glacial sediment.The continental glaciers advanced and retreated many times across those areas. During each ice advance, or glaciation, erosion and deposition occurred, and the landscape was again altered. Through successive glaciations, the landscape and the bedrock surface gradually came to resemble their present configurations. As continental ice sheets receded and the Pleistocene ended, erosion and deposition of sediment (for example in stream valleys) continued to shape the landscape up to the present day (albeit to a lesser extent than during glaciation). The interval of time since the last recession of the glaciers

  11. Final disposal of spent nuclear fuel in Finnish bedrock. Haestholmen site report

    International Nuclear Information System (INIS)

    Anttila, P.; Ahokas, H.; Front, K.

    1999-06-01

    Posiva Oy is studying the Finnish bedrock for the geological disposal of spent nuclear fuel. The study is based on the site selection research programme started originally in 1983. The programme is in accordance with the decision in principle by the Council of State in 1983 and aims at the selection of one site in 2000. Four sites, Haestholmen in Loviisa, Kivetty in Aeaenekoski, Olkiluoto in Eurajoki and Romuvaara in Kuhmo, have been studied in detail. This report summarises the results of the site investigations carried out at Haestholmen. The Haestholmen area is located within the anorogenic Wiborg rapakivi granite batholith, about 1630 million years in age, representing one of the youngest rock formations in Finland. Wiborgite, pyterlite, porphyritic rapakivi granite and even-grained rapakivi granite are the rock types present. 25 bedrock structures have been modelled at the site. Most of them are steeply-dipping fracture zones trending NW-SE and NE-SW, but several sub-horizontal zones, mainly dipping to the N-NE and the SW, are also present. The rock mass between the fracture zones represents what is termed 'intact rock', which is typically hard, unweathered and sparsely fractured. The bedrock structures are generally hydraulically more conductive than the intact rock and their mean transmissivity is 8 x 10 -6 m 2 /s or 1.3 x 10 -6 m 2 /s, depending on how structures are defined. The corresponding mean of the hydraulic conductivity values measured for the intact rock using a 2 m packer interval is 1 x 10 -12 m/s, if a lognormal distribution for all measured values is assumed. A clear decrease in hydraulic conductivity with depth has been found in the intact rock. In addition, the hydraulically conductive fractures seem to be more frequent and their transmissivities higher in the uppermost 100-200 m of the bedrock than at greater depths. The groundwater chemistry reflects the post-glacial history of the island of Haestholmen, which rose from the Baltic Sea some

  12. Bedrock river erosion measurements and modelling along a river of the Frontal Himalaya

    Science.gov (United States)

    Lave, Jerome; Dubille, Matthieu

    2017-04-01

    River incision is a key process in mountains denudation and therefore in landscape evolution models. Despite its importance, most incision models for mountain rivers rely on simplified, or quite empirical relations, and generally only consider annual average values for water discharge and sediment flux. In contrast, very few studies consider mechanistic models at the timescale of a flood, and try to bridge the gap between experimental or theoretical approaches and long term river incision studies. In this contribution, we present observations made during 7 monsoon seasons on fluvial bedrock erosion along the Bakeya river across the Frontal Himalaya in Central Nepal. Along its lower gorge, this river incises alternation of indurated sandstone and less resistant claystone, at Holocene rates larger than 10mm/yr. More importantly, its upper drainage mostly drains through non-cohesive conglomerate which allows, in this specific setting, estimating the bedload characteristics and instantaneous fluxes, i.e. a pre-requisite to test mechanistic models of fluvial erosion. During the study period, we monitored and documented the channel bank erosion in order to understand the amplitude of the erosion processes, their occurrence in relation with hydrology, in order to test time-integrated models of erosion. Besides hydrologic monitoring, erosion measurements were threefold: (1) at the scale of the whole monsoon, plucking and block removal by repeated photo surveys of a 400m long channel reach, (2) detailed microtopographic surveys of channel bedrock elevation along a few sandstone bars to document their abrasion, (3) real time measurement of fluvial bedrock wear to document erosion timing using a new erosion sensor. Results indicate that: 1. Erosion is highly dependent on rock resistance, but on average block detachment and removal is a more efficient process than bedrock attrition, and operates at a rate that permit channel banks downcutting to keep pace with Holocene uplift

  13. Loviisa power station, final disposal of reactor waste geophysical methods in structural study of the bedrock of Haestholmen

    International Nuclear Information System (INIS)

    Rouhiainen, Pekka

    1986-05-01

    The repository for low- and intermediate - level reactor wastes of the Loviisa power plant is planned to be built in the bedrock of the power plant area. Studies in order to assess the suitability of the site were started in 1979. The main objective of the geophysical studies has been to provide information about the structure of soil and bedrock. Borehole geophysics has been used to determine properties and geometry of fractures and fractured zones. This report is based on earlier reports published within the YJT series, but also new results are introduced. Most of the material used in the interpretation of fractured zones in the bedrock is included in this report. The emphasis is on the methods which are considered the most useful ones, specially the cross-hole methods. (author)

  14. Estimations of durability of fracture mineral buffers in the Olkiluoto bedrock

    International Nuclear Information System (INIS)

    Luukkonen, A.

    2006-12-01

    This study attempts to make scenarios for the geochemical effects that the underground excavations in the Olkiluoto bedrock have on naturally occurring fracture mineral buffers. The excavations of underground research facilities and final repository galleries probably cause steep hydraulic gradients in some bedrock fractures. These gradients likely draw surficial waters within the fracture network and activate weathering processes deeper in rock fractures than in the natural undisturbed conditions. The present studies concentrate on the meteoric infiltration in a single rock fracture, and on the selected set of minerals believed to be significant buffers against pH/redox variations in groundwater. The modelling considers the possibility that the infiltrating meteoric water is soil water rich in dissolved inorganic carbon. Calcite, pyrite, quartz, amorphous silica, cordierite, hornblende, albite, K-feldspar, kaolinite, and illite are taken into account as reacting minerals. Simulations are done by varying the flow rate of water from 1 L/h to 100 L/h. The effects of mineral reactions onto porosity and permeability values are monitored as well. In the present study, however, the changes in physical properties of the fracture channel do not affect the flow rate of water. Furthermore, calculations also describe how cation exchange affects the studied fracture channel system. The simulations coupling the hydraulic flow and water-rock interaction were done with TOUGHREACT V1.0 code and with the EQ3/6-database implemented in the code. In part, the simulations were evaluation of the code capabilities, and verification of results to earlier PHREEQC-2 simulation results. The calculation results confirm the assumption that principal buffer against pH changes is calcite. All silicate reactions, with considered reactive surface areas, are by comparison of marginal importance. The only redox buffer in the calculations is pyrite, and consequently significant amounts of oxygen runs

  15. Stratigraphic architecture of bedrock reference section, Victoria Crater, Meridiani Planum, Mars

    Science.gov (United States)

    Edgar, Lauren A.; Grotzinger, John P.; Hayes, Alex G.; Rubin, David M.; Squyres, Steve W.; Bell, James F.; Herkenhoff, Ken E.

    2012-01-01

    The Mars Exploration Rover Opportunity has investigated bedrock outcrops exposed in several craters at Meridiani Planum, Mars, in an effort to better understand the role of surface processes in its geologic history. Opportunity has recently completed its observations of Victoria crater, which is 750 m in diameter and exposes cliffs up to ~15 m high. The plains surrounding Victoria crater are ~10 m higher in elevation than those surrounding the previously explored Endurance crater, indicating that the Victoria crater exposes a stratigraphically higher section than does the Endurance crater; however, Victoria strata overlap in elevation with the rocks exposed at the Erebus crater. Victoria crater has a well-developed geomorphic pattern of promontories and embayments that define the crater wall and that reveal thick bedsets (3–7m) of large-scale cross-bedding, interpreted as fossil eolian dunes. Opportunity was able to drive into the crater at Duck Bay, located on the western margin of Victoria crater. Data from the Microscopic Imager and Panoramic Camera reveal details about the structures, textures, and depositional and diagenetic events that influenced the Victoria bedrock. A lithostratigraphic subdivision of bedrock units was enabled by the presence of a light-toned band that lines much of the upper rim of the crater. In ascending order, three stratigraphic units are named Lyell, Smith, and Steno; Smith is the light-toned band. In the Reference Section exposed along the ingress path at Duck Bay, Smith is interpreted to represent a zone of diagenetic recrystallization; however, its upper contact also coincides with a primary erosional surface. Elsewhere in the crater the diagenetic band crosscuts the physical stratigraphy. Correlation with strata present at nearby promontory Cape Verde indicates that there is an erosional surface at the base of the cliff face that corresponds to the erosional contact below Steno. The erosional contact at the base of Cape Verde

  16. Stable isotope signatures of gases liberated from fluid inclusions in bedrock at Olkiluoto

    International Nuclear Information System (INIS)

    Eichinger, F.; Meier, D.; Haemmerli, J.; Diamond, L.

    2010-12-01

    Fluid inclusions in quartzes of the Olkiluoto bedrock contain gaseous N 2 , CO 2 , H 2 , CH 4 , and higher hydrocarbons in varying proportions. Stable carbon and hydrogen isotope signatures of the gas phases give valuable information on their origin and the formation conditions. In previous studies, a method to liberate and quantify the gases trapped in fluid inclusions was developed. It allowed determining the carbon isotope signatures of liberated CO 2 , CH 4 and higher hydrocarbons (HHC), but no hydrogen isotope data were acquired. The method was advanced and, in this study, also stable hydrogen isotopes of CH 4 and H 2 liberated from fluid inclusions could be analysed. The stable carbon signatures of methane and higher hydrocarbons, as well as the hydrogen isotope signatures of methane indicate a predominant thermogenic provenance for those gases. (orig.)

  17. A review of published literature on the effects of permafrost on the hydrogeochemistry of bedrock

    International Nuclear Information System (INIS)

    Cascoyne, M.

    2000-06-01

    of seawater, enhanced or depleted sulphate concentrations in certain groundwaters, and lighter isotopic signature of the saline waters caused by the ice-water isotopic fractionation. This review has found that salt-rejection processes undoubtedly will have occurred in groundwaters in the marine sediments and bedrock of the Baltic coast during the Pleistocene. Deeply penetrating permafrost in the bedrock would cause relatively pure water to form as ice in fractures and displace residual saline fluids, under density flow, to greater depths. The process could have occurred to a sufficient extent that large volumes of saline water were generated, some of which may currently remain in the fractured rock. In these waters, loss of sulphate by mirabilite precipitation would be expected to have occurred but, on warming and degradation of the permafrost, lower-salinity meltwaters would re-dissolve the mirabilite, giving rise to a SO 4 -rich groundwater. This may be the origin of groundwater that is currently identified as Litorina Sea water at the Aespoe and Olkiluoto sites. This mechanism differs from that suggested by Israeli workers who propose freezing of open seawater and infiltration of residual brines into the bedrock followed by lateral migration inland. The hypothesis presented here, of formation of saline waters and brines by permafrost aggradation and salt-rejection is more acceptable from a hydrogeological standpoint because the saline waters are formed in situ and need not migrate laterally. Further field evidence, coupled with modelling of depths of permafrost penetration, could be used to assess the volume and concentration of saline groundwater formed as a result of downward advancement of permafrost in the crystalline bedrock. (orig.)

  18. Mars 2001 Mission: Addressing Scientific Questions Regarding the Characteristics and Origin of Local Bedrock and Soil

    Science.gov (United States)

    Saunders, R. S.; Arvidson, R. E.; Weitz, C. M.; Marshall, J.; Squyres, S. W.; Christensen, P. R.; Meloy, T.; Smith, P.

    1999-09-01

    The Mars Surveyor Program 2001 Mission will carry instruments on the orbiter, lander and rover that will support synergistic observations and experiments to address important scientific questions regarding the local bedrock and soils. The martian surface is covered in varying degrees by fine materials less than a few mms in size. Viking and Pathfinder images of the surface indicate that soils at those sites are composed of fine particles. Wheel tracks from the Sojourner rover suggest that soil deposits are composed of particles 100 microns and soils are dominated by wom away through prolonged transport over the eons? Were they never generated to begin with? Or are they simply less easy to identify because do they not form distinctive geomorphic features such as dunes or uniform mantles that tend to assume superposition in the soil structure?

  19. The use of surface geophysical techniques to detect fractures in bedrock; an annotated bibliography

    Science.gov (United States)

    Lewis, Mark R.; Haeni, F.P.

    1987-01-01

    This annotated bibliography compiles references about the theory and application of surface geophysical techniques to locate fractures or fracture zones within bedrock units. Forty-three publications are referenced, including journal articles, theses, conference proceedings, abstracts, translations, and reports prepared by private contractors and U.S. Government agencies. Thirty-one of the publications are annotated. The remainder are untranslated foreign language articles, which are listed only as bibliographic references. Most annotations summarize the location, geologic setting, surface geophysical technique used, and results of a study. A few highly relevant theoretical studies are annotated also. Publications that discuss only the use of borehole geophysical techniques to locate fractures are excluded from this bibliography. Also excluded are highly theoretical works that may have little or no known practical application.

  20. Monitoring the bedrock stability in Olkiluoto. Summary of campaign based GPS measurements in 1996-2011

    International Nuclear Information System (INIS)

    Nyberg, S.; Kallio, U.; Haekli, P.; Jokela, J.; Koivula, H.; Saaranen, V.; Rouhiainen, P.

    2013-12-01

    The Finnish Geodetic Institute has monitored crustal deformations in Olkiluoto since mid-1990s. This is a final report of campaign based GPS measurements carried out in 1996-2011. The aim of the research has been monitoring the bedrock stability in the Olkiluoto area. The research were started in 1995, when a local GPS network of ten pillars, called inner network, was established on Olkiluoto Island. The research area was expanded in 2003- 2005 with four new pillars (outer network) established at 5-10 km distances from the inner network. One of the pillar points is the Olkiluoto permanent GPS station. Regular biannual measurement campaigns have been carried out on other pillar points

  1. Sediment Supply Differences Between Soil and Bedrock Dominated Landscapes, San Gabriel Mountains, CA

    Science.gov (United States)

    Heimsath, A. M.; Dibiase, R.; Whipple, K. X.; Walsh, J.

    2009-12-01

    The importance of quantifying sediment delivery to channels is clear across disciplines. Processes that produce regolith, transport sediment, and incise valleys are complex, however, and are influenced by tectonic, lithologic, climatic, and anthropogenic factors in poorly constrained ways. As a result of our incomplete understanding of these processes, the extensive information encoded in the topography of a landscape remains out of reach. There remain significant gaps in our understanding of this interface between humans, the atmosphere, biosphere, and lithosphere. One of the most significant gaps is quantifying the controls on soil presence or absence in hilly and mountainous regions and the impacts of these controls on sediment supply to channels. Here we evaluate the controls exerted by erosion on soil production rates in the San Gabriel Mountains, California, measured by in situ produced cosmogenic nuclide (10Be) analyses and two widely used topographic metrics: mean hillslope gradient and the channel steepness index. We present data that show that the transition from soil-mantled to rocky landscapes is set by the maximum rate of soil production. Seventy measurements of 10Be concentrations in detrital sands collected from catchments spanning our field area yield a strikingly clear relationship between mean basin slope and average erosion rate. These data quantify a clear increase of erosion rate with mean slope, from the relatively gentle catchments in the west (10 degrees avg. slope) to the steepest soil mantled catchments near the middle of the range (30 degrees avg. slope). Above about 30 degrees, slopes are at threshold despite a factor of five increase in erosion rates, but become bedrock-dominated. To test controls on the transition from soil to bedrock-dominated landscapes, we measured soil production rates from point samples of bedrock and saprolite in forty-seven soil pits from across different soil-mantled hillslopes spanning the study area. Although

  2. A review of published literature on the effects of permafrost on the hydrogeochemistry of bedrock

    International Nuclear Information System (INIS)

    Gascoyne, M.

    2000-04-01

    , enhanced or depleted sulphate concentrations in certain groundwaters, and lighter isotopic signature of the saline waters caused by the ice-water isotopic fractionation. This review has found that salt-rejection processes undoubtedly will have occurred in groundwaters in the marine sediments and bedrock of the Baltic coast during the Pleistocene. Deeply penetrating permafrost in the bedrock would cause relatively pure water to form as ice in fractures and displace residual saline fluids,under density flow, to greater depths. The process could have occurred to a sufficient extent that large volumes of saline water were generated, some of which may currently remain in the fractured rock. In these waters,loss of sulphate by mirabilite precipitation would be expected to have occurred but, on warming and degradation of the permafrost,lower-salinity meltwaters would re-dissolve the mirabilite, giving rise to a SO 4 -rich groundwater. This may be the origin of groundwater that is currently identified as Litorina Sea water at the Aespoe and Olkiluoto sites. This mechanism differs from that suggested by Israeli workers who propose freezing of open seawater and infiltration of residual brines into the bedrock followed by lateral migration inland. The hypothesis presented here, of formation of saline waters and brines by permafrost aggradation and salt-rejection is more acceptable from a hydrogeological standpoint because the saline waters are formed in situ and need not migrate laterally. Further field evidence, coupled with modelling of depths of permafrost penetration, could be used to assess the volume and concentration of saline groundwater formed as a result of downward advancement of permafrost in the crystalline bedrock

  3. Natural radioactivity of bedrock bath instruments and hot spring instruments in Japan

    International Nuclear Information System (INIS)

    Kazuki Iwaoka; Hiroyuki Tabe; Hidenori Yonehara

    2013-01-01

    In Japan, bedrock bath instruments and hot spring instruments that contain natural radioactive nuclides are commercially available. In this study, such instruments containing natural radioactive nuclides, currently distributed in Japan, were collected and the radioactivity concentration of 238 U series, 232 Th series, and 40 K in them was determined by gamma ray spectrum analyses. Effective doses to workers and general consumers handling the materials were estimated, revealing the radioactivity concentration of 238 U series, 232 Th series, and 40 K to be lower than critical values given in the IAEA Safety Guide. The maximum effective doses to workers and general consumers were 210 and 6.1 μSv y -1 , respectively. These values are lower than the intervention exemption level (1,000 μSv y -1 ) given in ICRP Publ. 82. (author)

  4. Cross-hole fracture connectivity assessed using hydraulic responses during liner installations in crystalline bedrock boreholes

    Science.gov (United States)

    Persaud, Elisha; Levison, Jana; Pehme, Peeter; Novakowski, Kentner; Parker, Beth

    2018-01-01

    In order to continually improve the current understanding of flow and transport in crystalline bedrock environments, developing and improving fracture system characterization techniques is an important area of study. The presented research examines the installation of flexible, impermeable FLUTe™ liners as a means for assessing cross-hole fracture connectivity. FLUTe™ liners are used to generate a new style of hydraulic pulse, with pressure response monitored in a nearby network of open boreholes drilled in gneissic rock of the Canadian Shield in eastern Ontario, Canada. Borehole liners were installed in six existing 10-15 cm diameter boreholes located 10-35 m apart and drilled to depths ranging between 25-45 m. Liner installation tests were completed consecutively with the number of observation wells available for each test ranging between one and six. The collected pressure response data have been analyzed to identify significant groundwater flow paths between source and observation boreholes as well as to estimate inter-well transmissivity and storativity using a conventional type-curve analysis. While the applied solution relies on a number of general assumptions, it has been found that reasonable comparison can be made to previously completed pulse interference and pumping tests. Results of this research indicate areas where method refinement is necessary, but, nonetheless, highlight the potential for use in crystalline bedrock environments. This method may provide value to future site characterization efforts given that it is complementary to, and can be used in conjunction with, other currently employed borehole liner applications, such as the removal of cross-connection at contaminated sites and the assessment of discrete fracture distributions when boreholes are sealed, recreating natural hydraulic gradient conditions.

  5. Geoelectrical Response of a Hyporheic Zone within a Fractured Sedimentary Bedrock Riverbed

    Science.gov (United States)

    Steelman, C. M.; Kennedy, C. S.; Capes, D. C.; Parker, B. L.

    2015-12-01

    Fractured sedimentary bedrock aquifers represent an important source of water for many communities around the world. Although the effective porosities of these aquifers are extremely low relative to their unconsolidated counterparts, the existence of dense networks of interconnected fractures, dissolution-enhanced conduits or karst features can result in productive, yet heterogeneous and anisotropic, flow systems. Fluid-filled fractures remain connected to the porous matrix through advective-diffusive processes. This dual porosity concept is routinely applied to groundwater resource and contaminant transport studies; however, they have only recently been examined in shallow hyporheic environments, where groundwater and surface water influence one another through water and solute exchange across a streambed. Needless to say, there remains a gap in our conceptual understanding of hyporheic zones along rivers where water flowing through high-permeability fracture networks variably interacts with porewater residing in the low-permeability matrix. It is hypothesized that bedrock rivers will possess some measure of a hyporheic zone, albeit one that is governed by a vertical/horizontal fracture network but remains connected to the porous matrix. Hydrogeophysical methods provide a non-invasive means of assessing the scale and variability of critical zone dynamics. Here, we focus on the capacity of surface electrical resistivity for the detection and monitoring of a seasonally variable hyporheic zone at a field station located along the Eramosa River near Guelph, Ontario, Canada. Unlike conventional hydrogeological methods which potentially bias conduction in the fractures, surface resistivity is sensitive to the bulk electrical conductivity of the formation, making it more suited for detection of matrix conditions. Electrical resistivity data was collected along two 50 m profiles along a pool-riffle sequence on a daily to weekly interval from July 2014 to July 2015 and

  6. Bedrock stability in southeastern Sweden. Evidence from fracturing in the ordovician limestones of northern Oeland

    International Nuclear Information System (INIS)

    Milnes, A.G.; Gee, D.G.

    1992-09-01

    The stability of the bedrock in SE Sweden with regard to radioactive waste disposal has recently been the subject of some controversy. In order to better assess the age and significance of fracturing in the Precambrian basement at the site of the Aespoe Hard Rock Laboratory (HRL), near Oskarshamn, a detailed analysis of fracturing in the lower Ordovician limestones exposed along the west coast of the neighbouring island of Oeland has been carried out. The limestones form continuously exposed shore platforms, in segments up to 30 m broad and several kilometres long. These, and numerous quarries, provide ideal objects for quantitative analysis (ground and air photo mapping, scanline logging), and unique opportunities for investigating the amount of movement on the fractures, because of well-developed bedding and abundant rod-shaped fossils on the bedding surfaces. The fracture patterns are dominated by two sets of subvertical fractures, a NW trending closely spaced and strongly orientated set and a NNE-ENE trending widely spaced and variably orientated set. Only about 10% of the fractures in both sets show lateral fossil displacement, with maximum movement of 5 cm, and only 3% of the fractures show vertical displacement of bedding (maximum 8 cm). All in all, the lower Ordovician limestones along the exposed shoreline have suffered remarkably little deformation since deposition, i.e. over the last 500 million years. Appreciable bedrock instability, if it occurred, must have been concentrated offshore, or in the unexposed segments of the coastline, where some weak indications of slight movement (changes of a few metres in stratigraphic level) have been observed. Among other recommendations for further work, geophysical investigations to test these indications are suggested. (54 refs.)

  7. The role of uncertainty in bedrock depth and hydraulic properties on the stability of a variably-saturated slope

    NARCIS (Netherlands)

    Gomes, Guilherme J.C.; Vrugt, Jasper A.; Vargas, Eurípedes A.; Camargo, Julia T.; Velloso, Raquel Q.; van Genuchten, Martinus Th

    We investigate the uncertainty in bedrock depth and soil hydraulic parameters on the stability of a variably-saturated slope in Rio de Janeiro, Brazil. We couple Monte Carlo simulation of a three-dimensional flow model with numerical limit analysis to calculate confidence intervals of the safety

  8. A Test of the Circumvention-of-Limits Hypothesis in Scientific Problem Solving: The Case of Geological Bedrock Mapping

    Science.gov (United States)

    Hambrick, David Z.; Libarkin, Julie C.; Petcovic, Heather L.; Baker, Kathleen M.; Elkins, Joe; Callahan, Caitlin N.; Turner, Sheldon P.; Rench, Tara A.; LaDue, Nicole D.

    2012-01-01

    Sources of individual differences in scientific problem solving were investigated. Participants representing a wide range of experience in geology completed tests of visuospatial ability and geological knowledge, and performed a geological bedrock mapping task, in which they attempted to infer the geological structure of an area in the Tobacco…

  9. A Dataset of Rock Strength Along the Mixed Bedrock-alluvial Colorado River-Quantifying a Fundamental Control in Geomorphology

    Science.gov (United States)

    Pederson, J. L.; Bursztyn, N.

    2014-12-01

    Bedrock strength is a key parameter in slope stability, landscape erosion, and fluvial incision, though it is typically ignored or at best indirectly constrained in models, as with the k erodability parameter in stream-power formulations. Indeed, empirical datasets of rock strength suited to address geomorphic questions are rare, in part because of the difficulty in measuring those rocks that are heterolithic, weak, or poorly exposed. We have completed a large dataset of measured bedrock strength organized by rock units exposed along the length of the trunk Colorado-Green river through the Colorado Plateau of the western U.S. Measurements include Selby RMS, fracturing, and field compressive tests at 168 localities, as well as 672 individual-sample tensile-strength tests in the laboratory. These rock strength results are compared to geomorphic metrics of unit stream power, river gradient, valley-bottom width, and local relief through the arid Colorado Plateau. Our measurements trend coherently and logically with bedrock type and age/induration, especially in the case of tensile strength and when the influence of fracturing is also considered, signs that the dataset is robust. Focusing on bedrock (rather than alluvial) reaches of the fluvial transect and tensile strength, there is a positive rank-correlation and a strong power-law correlation between reach-averaged rock strength and unit stream power, as well as an elegant linear relation between tensile strength and river gradient. To address the problem of immeasureable rock types, we utilize the inverse power-law scaling between tensile strength and valley-bottom width to estimate the "effective" tensile strength of heterolithic, shale-rich bedrock in alluvial reaches. These results suggest that tensile strength varies to at least an order-of-magnitude smaller values than evident with directly testable rocks in this landscape, with implications for scaling erodibility parameters. Overall, results lead to the

  10. Assessing the Dominant Processes Controlling Mineralized Groundwater Chemistry of Bedrock Aquifers on the Niagara Peninsula, Ontario, Canada

    Science.gov (United States)

    Smal, C. A.; Slater, G.; Hamilton, S. M.

    2016-12-01

    The Ontario Geological Survey identified an area of highly mineralized groundwater chemistry exceeding average values for host bedrock formations following geochemical mapping on the Niagara Peninsula. Extensive sampling from domestic and monitoring wells at a density of 1 sample per 5x5 km2 was conducted in the summer of 2015 on the Niagara Peninsula to determine the geological and biogeochemical processes controlling groundwater chemistry. Following statistical analysis, groundwater samples were subdivided into 7 clusters and then grouped into three larger geochemical zones based on chemical associations. The Salina Formation Zone in the central Peninsula is characterized by older, low tritium waters with isotopically depleted δ18OH2O values suggesting the presence of glacially-impacted groundwater of Pleistocene age. The Salina Formation Zone shows evidence for being highly influenced by water-rock interaction with elevated concentrations of S2-, Ca2+, Mg2+, K+, Na+, SO42-, Cl-, Br- and Sr2+. Adjacent to the Salina Formation Zone is the low conductivity, bedrock influenced, Guelph Formation Zone, characterized by high F-, variable geochemical facies and low tritium values. In the north and south, high bacterial counts and tritium values suggests evidence of rapid recharge through thin drift and karst-influenced, exposed bedrock surfaces. Within the geochemical zones, regions of varying biogeochemical cycling were observed using sulfur and carbon isotopic tracers, relating to local variations in groundwater chemistry. Some of these local variations may be related to the presence of abandoned, corroding gas wells on the Peninsula. Predominate controls on groundwater chemistry include groundwater recharge along the Niagara and Onondaga Escarpments, thick impermeable glacial sediment cover overlying bedrock troughs and buried bedrock channels, and water-rock interaction in the central and east-central Niagara Peninsula.

  11. Hillslope response to sprinkling and natural rainfall using velocity and celerity estimates in a slate-bedrock catchment

    Science.gov (United States)

    Scaini, Anna; Hissler, Christophe; Fenicia, Fabrizio; Juilleret, Jérôme; Iffly, Jean François; Pfister, Laurent; Beven, Keith

    2018-03-01

    Subsurface flow is often recognized as a dominant runoff generation process. However, observing subsurface properties, and understanding how they control flow pathways, remains challenging. This paper investigates how surface slope and bedrock cleavage control subsurface flow pathways in a slate bedrock headwater catchment in Luxembourg, characterised by a double-peak streamflow response. We use a range of experimental techniques, including field observations of soil and bedrock characteristics, and a sprinkling experiment at a site located 40 m upslope from the stream channel. The sprinkling experiment uses Br- as a tracer, which is measured at a well downslope from the plot and at various locations along the stream, together with well and stream hydrometric responses. The sprinkling experiment is used to estimate velocities and celerities, which in turn are used to infer flow pathways. Our results indicate that the single or first peak of double-peak events is rainfall-driven (controlled by rainfall) while the second peak is storage-driven (controlled by storage). The comparison between velocity and celerity estimates suggests a fast flowpath component connecting the hillslope to the stream, but velocity information was too scarce to fully support such a hypothesis. In addition, different estimates of celerities suggest a seasonal influence of both rainfall intensity rate and residual water storage on the celerity responses at the hillslope scale. At the catchment outlet, the estimated of the total mass of Br- recovered in the stream was about 2.5% of the application. Further downstream, the estimate mass of Br- was about 4.0% of the application. This demonstrates that flowpaths do not appear to align with the slope gradient. In contrast, they appear to follow the strike of the bedrock cleavage. Our results have expanded our understanding of the importance of the subsurface, in particular the underlying bedrock systems, and the importance of cleavage orientation

  12. A comparison of methods used in mapping of Pleistocene-bedrock unconformity: Conventional manual versus surface modeling

    Energy Technology Data Exchange (ETDEWEB)

    Weibel, C.P.; Abert, C.C.; Kempton, J.P. (Illinois State Geological Survey, Champaign, IL (United States))

    1993-03-01

    Surface modeling software packages allow geologists to model and map topographic and stratigraphic horizons. These map products, however, often differ from maps prepared without computerized mapping. The authors mapping of the Pleistocene-bedrock unconformity in east-central Illinois (1:100,000-scale), which includes the Mahomet paleovalley, illustrates this situation and demonstrates how both mapping methods, manual and computer, contribute to a better understanding of the paleovalley. A conventional hand-drawn map was constructed over a number of years by manually plotting and contouring bedrock elevations, primarily from water well logs, onto various county and local topographic bases. A computer-generated map of the same area was completed as part of a recent project to map the bedrock geology. It was prepared by carefully selecting data, which included geographic coordinates, unique well identification numbers, and bedrock elevations. Primary data sources were hydrocarbon exploration and storage wells. Digitizing the hand-drawn map allowed the two maps to be overlaid and compared. Several significant geomorphic features appeared on one map and not the other because of the use of different databases and inconsistent selection of data used for the hand-drawn map. The hand-drawn map appears more realistic, i.e., like a modern surface, because the mappers used their knowledge of geomorphic concepts in drawing the contours. Most of the data selection for the computer-generated map was completed prior to plotting of the map and therefore is less susceptible to bias interpretations. The computer-generated map, however, is less topographically realistic in areas where data are sparse because the extrapolation methods used to define the surface do not recognize geologic processes or bedrock lithology.

  13. Yield of bedrock wells in the Nashoba terrane, central and eastern Massachusetts

    Science.gov (United States)

    DeSimone, Leslie A.; Barbaro, Jeffrey R.

    2012-01-01

    The yield of bedrock wells in the fractured-bedrock aquifers of the Nashoba terrane and surrounding area, central and eastern Massachusetts, was investigated with analyses of existing data. Reported well yield was compiled for 7,287 wells from Massachusetts Department of Environmental Protection and U.S. Geological Survey databases. Yield of these wells ranged from 0.04 to 625 gallons per minute. In a comparison with data from 103 supply wells, yield and specific capacity from aquifer tests were well correlated, indicating that reported well yield was a reasonable measure of aquifer characteristics in the study area. Statistically significant relations were determined between well yield and a number of cultural and hydrogeologic factors. Cultural variables included intended water use, well depth, year of construction, and method of yield measurement. Bedrock geology, topography, surficial geology, and proximity to surface waters were statistically significant hydrogeologic factors. Yield of wells was higher in areas of granites, mafic intrusive rocks, and amphibolites than in areas of schists and gneisses or pelitic rocks; higher in valleys and low-slope areas than on hills, ridges, or high slopes; higher in areas overlain by stratified glacial deposits than in areas overlain by till; and higher in close proximity to streams, ponds, and wetlands than at greater distances from these surface-water features. Proximity to mapped faults and to lineaments from aerial photographs also were related to well yield by some measures in three quadrangles in the study area. Although the statistical significance of these relations was high, their predictive power was low, and these relations explained little of the variability in the well-yield data. Similar results were determined from a multivariate regression analysis. Multivariate regression models for the Nashoba terrane and for a three-quadrangle subarea included, as significant variables, many of the cultural and

  14. Indications of postglacial and recent bedrock movements in Finland and Russian Karelia

    Energy Technology Data Exchange (ETDEWEB)

    Kuivamaeki, A.; Vuorela, P.; Paananen, M

    1998-12-31

    This report is mainly a summary report of the studies done 1986 - 1997 by the Geological Survey of Finland/Nuclear Waste Disposal Research on postglacial faulting (PG-faults) and recent bedrock movements. Most of the results have already been published in other YST-reports in Finnish. The first part of the report deals with the postglacial faults in Finland and in the second part the problems connected with the origin and age of paleoseismic dislocations found in Russian Karelia are described. The final part deals with the present vertical and horizontal movements of Finnish bedrock. The Pasmajaervi PG-fault is the most thoroughly studied PG-fault in Finland. Around the fault lineament interpretations and geophysical ground measurements have been done and the fault zone has been penetrated with two drill holes. Three levelling networks and one GPS-network have been established for revealing any recent movements of the PG-fault area. Other PG-faults studied, but not in the same detail, are Venejaervi, Ruostejaervi, Suasselkae and Vaalajaervi PG-faults. The PG-faults in Finland strike in the SW-NE direction and dip to the SE with the exception of the Vaalajaervi PG-fault. It strikes in the NW-SE direction. The dip direction is unknown. The length of the PG-faults is 4-36 km and the scarp height 0-12 m. PG-faults are reverse faults and they are located in old, reactivated fracture zones. The results of drillings and resistivity soundings in the Pasmajaervi PG-fault indicate, that the dip angle of 45 deg in the surface becomes more gentle with the increasing depth. This result may be important from a technical point of view when designing nuclear waste repositories. The strike directions of the PG-faults are perpendicular with the direction of prevailing horizontal maximum stress. The structure and location of the PG-faults is in accordance with the model presented by Muir Wood for the origin of PG-faults. The exceptional direction of the Vaalajaervi PG-fault is

  15. Groundwater management in coastal zones and on islands in crystalline bedrock areas of Sweden

    Science.gov (United States)

    Banzhaf, Stefan; Ekström, Linda Louise; Ljungkvist, Andreas; Granberg, Maria; Merisalu, Johanna; Pokorny, Sebastian; Barthel, Roland

    2017-04-01

    Groundwater problems in coastal regions are usually not associated with the sparsely populated shores of water-rich Scandinavia. However, the combination of geology and the specific conditions of water usage create challenges even there. Along the Swedish coast, much of the groundwater occurs in fractured bedrock or in relatively small, shallow, and isolated quaternary sedimentary formations. Those aquifers cannot provide water to larger permanent settlements and are thus neither useful for the public water supply nor have previously received much attention from water authorities or researchers. However, of the 450,000 private wells in Sweden, many are located in coastal areas or on islands, creating pressure on groundwater resources in summer months as periods with low or no natural groundwater recharge. In view of the increasing water demand, as well as the awareness of environmental impacts and climate change, Swedish municipalities now recognize groundwater usage in coastal areas is a major concern. Here, we present the results of an investigation on the "Koster" archipelago which forms a microcosm of coastal zone groundwater problems in Sweden. Koster's geology is dominated by fractured, crystalline bedrock with occasional shallow quaternary deposits in between. With around 300 permanent residents, and up to 6,000 summer guests in peak holiday season, the existing water supply based on 800 private wells is at its limit. Water availability forms an obstacle to future development and the current mode of operation is unsustainable. Therefore, the municipality must decide how to secure future water supply which involves complex legal problems, as well as social, cultural, economic, hydrogeological, and environmental questions. As there are no observation wells on the islands, we used approximately 220 of the 800 wells (65% dug and shallow, 35% drilled and up to 120m deep) for our monitoring. Additionally, water samples were collected by property owners on four

  16. The evolution of stream coupled hillslopes by bedrock landsliding in a rapidly eroding mountain belt, Taiwan

    Science.gov (United States)

    Wenske, Dirk; Jen, Chia-Hung; Böse, Margot; Lin, Jiun-Chuan

    2010-05-01

    Being affected frequently by violent weather condition such as typhoons and regular seismic activity, the high mountains of Taiwan belong to the earth's most dynamic landscapes. In the fast-eroding mountain belt of Taiwan, hillslopes and valley systems have been reported to show a high level of coupling (Hovius et al. 2000). In the catchment of the Tachia river numerous bedrock landslides occur frequently as a result of seismic events and typhoons (Lin et al. 2006). This study attempts to take a closer look at the temporal and spatial pattern of hillslope evolution at two study sites in the upper catchement of the Tachia river. Therefore we have carried out a repeated field surveying of active slopes by means of traditional survey instruments and terrestrial laser scanning from early 2008 until late 2009 on a half year basis. Additionally, a set of aerial photos and satellite images from 1969, 1980,2001, 2004, 2007, 2008 and 2009 is used to assess the long-term and short-term changes of the river channel. Near the town of Huan Shan, the valley bottom shows elevations around 1520 m above sea level and the river is draining and upstream area of 155 km². Downstream of Huan Shan lies the confluence of the Tachia River and two of its tributaries, namely the Nanhu River and the Hehuan River. Therefore, the catchment area upstream of second study area in Sung Mao is considerably larger being of 420 km², in that place, the current level of the channel varies around 1425 m above sea level. In the two study areas strong lateral erosion has been observed. In the case of the Sung Mao study area, the latter is linked to a severe aggradation of sediments in the channel since the building of the Dechi Dam downstream. The active hillslopes have been surveyed and their reaction to the typhoons in 2008 and 2009 is studied. Rates of sediment yield from the slopes have been calculated for three periods between April 2008, November 2008, April 2009 and November 2009. Furthermore, the

  17. A new, multi-resolution bedrock elevation map of the Greenland ice sheet

    Science.gov (United States)

    Griggs, J. A.; Bamber, J. L.; Grisbed Consortium

    2010-12-01

    Gridded bedrock elevation for the Greenland ice sheet has previously been constructed with a 5 km posting. The true resolution of the data set was, in places, however, considerably coarser than this due to the across-track spacing of ice-penetrating radar transects. Errors were estimated to be on the order of a few percent in the centre of the ice sheet, increasing markedly in relative magnitude near the margins, where accurate thickness is particularly critical for numerical modelling and other applications. We use new airborne and satellite estimates of ice thickness and surface elevation to determine the bed topography for the whole of Greenland. This is a dynamic product, which will be updated frequently as new data, such as that from NASA’s Operation Ice Bridge, becomes available. The University of Kansas has in recent years, flown an airborne ice-penetrating radar system with close flightline spacing over several key outlet glacier systems. This allows us to produce a multi-resolution bedrock elevation dataset with the high spatial resolution needed for ice dynamic modelling over these key outlet glaciers and coarser resolution over the more sparsely sampled interior. Airborne ice thickness and elevation from CReSIS obtained between 1993 and 2009 are combined with JPL/UCI/Iowa data collected by the WISE (Warm Ice Sounding Experiment) covering the marginal areas along the south west coast from 2009. Data collected in the 1970’s by the Technical University of Denmark were also used in interior areas with sparse coverage from other sources. Marginal elevation data from the ICESat laser altimeter and the Greenland Ice Mapping Program were used to help constrain the ice thickness and bed topography close to the ice sheet margin where, typically, the terrestrial observations have poor sampling between flight tracks. The GRISBed consortium currently consists of: W. Blake, S. Gogineni, A. Hoch, C. M. Laird, C. Leuschen, J. Meisel, J. Paden, J. Plummer, F

  18. Lithological and structural bedrock model of the Haestholmen study site, Loviisa, SE Finland

    Energy Technology Data Exchange (ETDEWEB)

    Front, K.; Paulamaeki, S.; Ahokas, H.; Anttila, P

    1999-10-01

    The Haestholmen study site is located within the anorogenic Wiborg rapakivi granite batholith, 1640 1630 Ma in age. The bedrock consists of various rapakivi granites, which can be divided into three groups or lithological units: (1) wiborgite and pyterlite, (2) porphyritic rapakivi granite, and (3) even-grained or weakly porphyritic rapakivi granite, pyterlite being the dominant rock type. The evengrained and weakly porphyritic rapakivi granite has been interpreted to form a younger intrusive unit with a thickness of ca. 500 m, dipping approx. 20 deg to the NNW-NNE. Surface fractures form a distinct orthogonal system, with three perpendicular fracture directions: fractures dipping steeply (dip >75 deg) to the NE-SW and NW-SE plus subhorizontal (dip <30 deg) fractures. The fracturing in the outcrops is sparse,the average fracture frequency being 0.6 fractures/m. The majority of the fractures in the drill cores are horizontal or very gently dipping and there is no difference in fracture orientations in regard to rock type or depth. Core samples are usually slightly fractured (1 - 3 fractures/m), even-grained rapakivi granites being in places abundantly fractured (3 10 fractures/m. The broken sections in Haestholmen core samples represent about 4.6 % of the total length of the samples. Calcite, dolomite, Fe- hydroxides and clay minerals (illite, montmorillonite and kaolinite) form the most typical fracture mineral phases throughout the drill cores. Core discing is locally seen as repeated fracture-like subparallel cracks in core with spacing of about some millimetres to tens of millimetres. The structural model contains 27 structures (denoted by the term R+number), more than half of which have been verified by direct observations from boreholes or from the VLJ repository. The remaining structures are mainly based on the geophysical interpretation, and have been classified as probable or possible fracture zones. In addition, local structures with uncertain orientation

  19. Wildfire-induced initiation of debris flows in a steep bedrock landscape, San Gabriel Mountains, California

    Science.gov (United States)

    Ulizio, T. P.; Palucis, M. C.; Fuller, B. M.; Lamb, M. P.

    2017-12-01

    Steep, rocky landscapes often produce large sediment yields and increased debris flow activity following wildfire. There are two main hypotheses for debris flow initiation in burned regions during rain storms: (1) debris flows initiate from failure of the soil mantle on hillslopes where fire has destroyed root systems resulting in loss of soil strength, and (2) debris flows initiate in river channels that have been loaded by dry ravel following incineration of vegetation dams on hillslopes. To evaluate these hypotheses, we monitored a steep first-order catchment that burned in the 2016 Fish Canyon fire within the front range of the San Gabriel Mountains, CA. Following each post-fire storm, we measured the hillslope and channel topography using UAV imaging and structure-from-motion, and monitored activity during storm events with field cameras. Following the fire, but prior to the first storm event, most of the hillslopes were stripped to bedrock and 0.5 m of dry ravel had accumulated along the length of the channel. By using measurements of sediment storage behind vegetation in a nearby unburned catchment, but with a similar burn history, we found that much of the loose sediment in the channel can be attributed to dry ravel following incineration of vegetation dams. Throughout the rainy season, the catchment produced a series of debris flows that evacuated the accumulated dry ravel in the channel, exposed bedrock in the channel, and built a debris flow fan across a terrace that abuts the downstream end of the channel. Although later storms were larger, most sediment transport occurred during the first few storms, indicating that sediment supply can limit debris flow activity, and that larger storms do not necessarily produce larger debris flows. Our measurements of the volume of the newly formed debris flow fan approximately matches the volume of evacuated ravel from the channel, and we did not observe landslide scars on hillslopes. Together, these observations and

  20. Significance and estimations of lifetime of natural fracture mineral buffers in the Olkiluoto bedrock

    International Nuclear Information System (INIS)

    Luukkonen, A.; Pitkaenen, P.; Partamies, S.

    2004-03-01

    This study attempts to make scenarios what geochemical effects the future underground excavations in the Olkiluoto bedrock have on naturally occurring fracture mineral buffers. The excavations of underground research facilities, and final repository galleries will cause steep hydraulic gradients in the bedrock fractures. These gradients likely draw surficial waters within the fracture network and activate weathering processes deeper in rock fractures than in the natural undisturbed conditions. The studies are concentrated on the meteoric and seawater infiltration in the rock fractures, and on the selected minerals considered significant buffers against pH/redox variations in groundwater. Two approaches to calculate the scenarios are utilised. The equilibrium geochemical calculations consider variety of problems including several surficial water compositions, mixing cases between surficial water types, and couple buffer mineral assemblages. These equilibrium calculations indicate that meteoric water by far presents the most potential hazard for the Olkiluoto fracture minerals. In the calculated cases, seawater and the contamination of meteoric water with seawater during the water infiltration usually improved the performance of mineral buffers compared to the pure meteoric water cases. Of the Olkiluoto fracture minerals, calcite and pyrite turn out to be the most important buffer minerals against dissolved O 2 and low pH in groundwater. The kinetic geochemical approach concentrated on two meteoric water cases infiltrating into a narrow fracture channel. Calculations consider the possibilities that the infiltrating meteoric water is dissolved carbon containing soil water or almost 'distilled' rain water. Pyrite and calcite are taken into account as the buffering minerals. Several simulations are done by varying the recharge water compositions and the flow rates of water. It turns out that as long as volumetric flow rates within the 500-metre-channel considered are in

  1. Hydrochemistry of the Mahomet Bedrock Valley Aquifer, East-Central Illinois: indicators of recharge and ground-water flow

    Science.gov (United States)

    Panno, S.V.; Hackley, Keith C.; Cartwright, K.; Liu, Chao-Li

    1994-01-01

    A conceptual model of the ground-water flow and recharge to the Mahomet Bedrock Valley Aquifer (MVA), east-central Illinois, was developed using major ion chemistry and isotope geochemistry. The MVA is a 'basal' fill in the east-west trending buried bedrock valley composed of clean, permeable sand and gravel to thicknesses of up to 61 m. It is covered by a thick sequence of glacial till containing thinner bodies of interbedded sand and gravel. Ground water from the MVA was found to be characterized by clearly defined geochemical regions with three distinct ground-water types. A fourth ground-water type was found at the confluence of the MVA and the Mackinaw Bedrock Valley Aquifer (MAK) to the west. Ground water in the Onarga Valley, a northeastern tributary of the MVA, is of two types, a mixed cation-SO42- type and a mixed cation-HCO3- type. The ground water is enriched in Na+, Ca2+, Mg2+, and SO42- which appears to be the result of an upward hydraulic gradient and interaction of deeper ground water with oxidized pyritic coals and shale. We suggest that recharge to the Onarga Valley and overlying aquifers is 100% from bedrock (leakage) and lateral flow from the MVA to the south. The central MVA (south of the Onarga Valley) is composed of relatively dilute ground water of a mixed cation-HCO3- type, with low total dissolved solids, and very low concentrations of Cl- and SO42-. Stratigraphic relationships of overlying aquifers and ground-water chemistry of these and the MVA suggest recharge to this region of the MVA (predominantly in Champaign County) is relatively rapid and primarily from the surface. Midway along the westerly flow path of the MVA (western MVA), ground water is a mixed cation-HCO3- type with relatively high Cl-, where Cl- increases abruptly by one to ??? two orders of magnitude. Data suggest that the increase in Cl- is the result of leakage of saline ground water from bedrock into the MVA. Mass-balance calculations indicate that approximately 9.5% of

  2. Bedrock topography beneath uppermost part of Aletsch glacier, Central Swiss Alps, revealed from cosmic-ray muon radiography

    Science.gov (United States)

    Nishiyama, Ryuichi; Ariga, Akitaka; Ariga, Tomoko; Käser, Samuel; Lechmann, Alessandro; Mair, David; Scampoli, Paola; Vladymyrov, Mykhailo; Ereditato, Antonio; Schlunegger, Fritz

    2017-04-01

    In mountainous landscapes such as the Central Alps of Europe, the bedrock topography is one of the most interesting subjects of study since it separates the geological substratum (bedrock) from the overlying unconsolidated units (ice). The geometry of the bedrock topography puts a tight constraint on the erosional mechanism of glaciers. In previous studies, it has been inferred mainly from landscapes where glaciers have disappeared after the termination of the last glacial epoch. However, the number of studies with a focus on the structure beneath active glaciers is limited, because existing exploration methods have limitation in resolution and mobility. The Eiger-μ project proposes a new technology, called muon radiography, to investigate the bedrock geometry beneath active glaciers. The muon radiography is a recent technique that relies on the high penetration power of muon components in natural cosmic rays. Specifically, one can resolve the internal density profile of a gigantic object by measuring the attenuation rate of the intensity of muons after passing through it, as in medical X-ray diagnostic. This technique has been applied to many fields such as volcano monitoring (eg. Ambrosino et al., 2015; Jourde et al., 2016; Nishiyama et al., 2016), detection of seismic faults (eg. Tanaka et al., 2011), inspection inside nuclear reactors, etc. The first feasibility test of the Eiger-μ project has been performed at Jungfrau region, Central Swiss Alps, Switzerland. We installed cosmic-ray detectors consisting of emulsion films at three sites along the Jungfrau railway tunnel facing Aletsch glacier (Jungfraufirn). The detectors stayed 47 days in the tunnel and recorded the tracks of muons which passed through the glacier and bedrock (thickness is about 100 m). Successively the films were chemically developed and scanned at University of Bern with microscopes originally developed for the analysis of physics experiments on neutrino oscillation. The analysis of muon

  3. SKB 91. Final disposal of spent nuclear fuel. Importance of the bedrock for safety

    International Nuclear Information System (INIS)

    1992-05-01

    The safety of a deep repository for spent nuclear fuel has been assessed in this report. The spent fuel is assumed to be encapsulated in a copper canister and deposited at a depth of 600 m in the bedrock. The primary purpose has been to shed light on the importance of the geological features of the site for the safety of a final repository. The assessment shows that the encapsulated fuel will, in all likelihood, be kept isolated from the groundwater for millions of years. This is considerably longer than the more than 100 000 years that are required in order for the toxicity of the waste to have declined to a level equivalent to that of rich uranium ores. However, in order to be able to study the role of the rock as a barrier to the dispersal of radioactive materials, calculations have been carried out under the assumption that waste canisters leak. The results show that the safety of a carefully designed repository is only affected to a small extent by the ability of the rock to retain the escaping radionuclides. The primary role of the rock is to provide stable mechanical and chemical conditions in the repository over a long period of time so that the function of the engineered barriers is not jeopardized. (187 refs.) (au)

  4. Feasibility study and technical proposal for long-term observations of bedrock stability with gps

    International Nuclear Information System (INIS)

    Ruizhi Chen; Kakkuri, J.

    1994-01-01

    In order to study the regional crustal deformation pattern in the territory of Finland, the Finnish Geodetic Institute is establishing the Finnish Permanent GPS Network, which is part of the Fennoscandian Permanent GPS Network. The Finnish GPS Network consists of a 12 stations located in different geological structures. The operation procedure of the network is described in the report. Feasibility study for monitoring the bedrock stability at local scale was performed. The study was carried out on the basis of an experiment on a baseline of 1041 metres. Twelve artificial movements ranging from 1 mm to 22 mm were generated with a precision-manufactured screw drive (with an accuracy of better than +-0.05 mm). The artificial movements were then detected with the GPS measurements. A preliminary analysis of the GPS data shows that the maximum difference between the GPS detected movements and the artificial movements is 0.9 mm with a standard deviation of +-0.46 mm. The observation time for reaching such accuracy is about 55 minutes. Three GPS networks were preliminarily designed for the radioactive waste disposal investigation sites of Olkiluoto, Kivetty and Romuvaara. Detailed research plan for achieving the best possible result from GPS measurements was proposed. (58 refs., 25 figs., 1 tab.)

  5. Geology and hydrology of the deep bedrock aquifers in eastern Colorado

    Science.gov (United States)

    Robson, S.G.; Banta, E.R.

    1987-01-01

    Deep bedrock aquifers are present in rocks of Cretaceous through Pennsylvanian age in eastern Colorado. These aquifers are the Laramie-Fox Hills (the uppermost aquifer studied), Fort Hays-Codell, Dakota-Cheyenne, Entrada-Dockum, Lyons, and Fountain. Structural mapping indicates the aquifers are 2,000 to 9,000 ft below land surface in most of eastern Colorado but outcrop in local areas in a narrow band along the Front Range of the Rocky Mountains. Recharge primarily occurs in outcrops and produces a northerly or easterly groundwater flow to discharge areas along the South Platte or Arkansas Rivers. Deep aquifers also discharge by underflow to Kansas and Nebraska. Some water-yielding strata in the Dakota-Cheyenne aquifer are not in hydraulic connection with the aquifer, and abnormal fluid pressures, trapped hydrocarbons, and high dissolved-solids concentrations are found in these strata. Temperature and dissolved-solids mapping indicate water temperatures of 100 to 210 in northeastern Colorado and a zone of relatively fresh water extending through a 7,000 sq mi area of the Dakota-Cheyenne aquifer in southeastern Colorado. Water levels in the Laramie-Fox Hills aquifer continue to decline as much as 12 ft/yr in local areas near Denver. (USGS)

  6. Bedrock Geology of the DFDP-2B Drill-Site, Central Alpine Fault, New Zealand

    Science.gov (United States)

    Toy, Virginia; Sutherland, Rupert; Townend, John

    2017-04-01

    Bedrock was encountered at drilled depths (MD) of 238.5-893.2 m (vertical depths of 238.4-818.0 m) in DFDP-2B, Whataroa River, Westland, New Zealand. Continuous sampling and onsite description of whole cuttings samples and thin sections allowed identification that the borehole terminated within amphibolite facies, Torlesse Composite Terrane-derived mylonites >200-400 m above the Alpine Fault principal slip zone (PSZ). The most diagnostic macro-and micro-structural features were the occurrence of shear bands and reduction in mean quartz grain sizes toward the Alpine Fault. Onsite optical microscopy and subsequent offsite electron microscopy both demonstrate: (i) reduction in grain size and (ii) change in composition to greater mica:quartz+feldspar, most markedly at 720 m MD (vertical depth of 695 m), inferred to result from either heterogeneous sampling due to variations in drilling parameters, or a change in rock type across a minor fault. Major oxide variations suggest the Alpine Fault alteration zone, as defined during DFDP-1, was not sampled.

  7. Quaternary deposits and weathered bedrock material as a source of dangerous radon emissions in Estonia

    Directory of Open Access Journals (Sweden)

    Petersell Valter

    2015-06-01

    Full Text Available The risk of dangerous radon emissions in Estonia is high, being among the highest in Europe. In almost 33 per cent of Estonian land area, the content of radon in soil-contained air exceeds the safe limit for unrestricted construction (50 kBq/m3. In such high radon-risk areas the concentration of radon in soil-contained air ranges from 50 to 400 kBq/m3, in a few cases reaching up to 2,100 kBq/m3 exceeding the permitted level for residential areas. The situation is particularly serious in the northernmost part of the country, where uranium-rich graptolite argillite (Dictyonema shale and the Obolus phosphorite are close to ground surface and their particles are constituent parts of Quaternary deposits. Radon emissions from bedrock have been investigated in detail, but to date Quaternary strata as a source of radon emissions are poorly studied. According to our measurements the highest concentrations of radon are related to tills containing clasts and fines of graptolite argillite and phosphorite. Glacial deposits include also granitoidal material, containing U, Th and K, which have been transported by glaciers from the outcrop areas of crystalline basement rocks in Finland and the Gulf of Finland. Due to weathering, outwash and repeated redeposition other genetic types are poorer in radioactive elements and they are weaker sources of radon.

  8. Radon in Soil Gas Above Bedrock Fracture Sets at the Shepley’s Hill Superfund Site

    Energy Technology Data Exchange (ETDEWEB)

    J.R. Giles; T.L. McLing; M.V. Carpenter; C.J. Smith; W. Brandon

    2012-12-01

    The Idaho National Laboratory (INL) recently provided technical support for ongoing environmental remediation activities at the Shepley’s Hill remediation site near Devens, MA (Figure 1). The technical support was requested as follow-on work to an initial screening level radiation survey conducted in 2008. The purpose of the original study was to assess the efficacy of the INL-developed Backpack Sodium Iodide System (BaSIS) for detecting elevated areas of natural radioactivity due to the decay of radon-222 gases emanating from the underlying fracture sets. Although the results from the initial study were mixed, the BaSIS radiation surveys did confirm that exposed bedrock outcrops have higher natural radioactivity than the surficial soils, thus a high potential for detecting elevated levels of radon and/or radon daughter products. (INL 2009) The short count times associated with the BaSIS measurements limited the ability of the system to respond to elevated levels of radioactivity from a subsurface source, in this instance radon gas emanating from fracture sets. Thus, it was postulated that a different methodology be employed to directly detect the radon in the soil gases. The CR-39 particle track detectors were investigated through an extensive literature and technology search. The relatively long deployment or “detection” time of several days, as well as the sensitivity of the measurement and robustness of the detectors made the CR-39 technology promising for deployment at the Shepley’s Hill site.

  9. Hydraulic Parameter Generation Technique Using a Discrete Fracture Network with Bedrock Heterogeneity in Korea

    Directory of Open Access Journals (Sweden)

    Jae-Yeol Cheong

    2017-12-01

    Full Text Available In instances of damage to engineered barriers containing nuclear waste material, surrounding bedrock is a natural barrier that retards radionuclide movement by way of adsorption and delay due to groundwater flow through highly tortuous fractured rock pathways. At the Gyeongju nuclear waste disposal site, groundwater mainly flows through granitic and sedimentary rock fractures. Therefore, to understand the nuclide migration path, it is necessary to understand discrete fracture networks based on heterogeneous fracture orientations, densities, and size characteristics. In this study, detailed heterogeneous fracture distribution, including the density and orientation of the fractures, was considered for a region that has undergone long periods of change from various geological activities at and around the Gyeongju site. A site-scale discrete fracture network (DFN model was constructed taking into account: (i regional fracture heterogeneity constrained by a multiple linear regression analysis of fracture intensity on faults and electrical resistivity; and (ii the connectivity of conductive fractures having fracture hydraulic parameters, using transient flow simulation. Geometric and hydraulic heterogeneity of the DFN was upscaled into equivalent porous media for flow and transport simulation for a large-scale model.

  10. Bedrock geologic and joint trend map of the Pinardville quadrangle, Hillsborough County, New Hampshire

    Science.gov (United States)

    Burton, William C.; Armstrong, Thomas R.

    2013-01-01

    The bedrock geology of the Pinardville quadrangle includes the Massabesic Gneiss Complex, exposed in the core of a regional northeast-trending anticlinorium, and highly deformed metasedimentary rocks of the Rangeley Formation, exposed along the northwest limb of the anticlinorium. Both formations were subjected to high-grade metamorphism and partial melting: the Rangeley during the middle Paleozoic Acadian orogeny, and the Massabesic Gneiss Complex during both the Acadian and the late Paleozoic Alleghanian orogeny. Granitoids produced during these orogenies range in age from Devonian (Spaulding Tonalite) to Permian (granite at Damon Pond), each with associated pegmatite. In the latest Paleozoic the Massabesic Gneiss Complex was uplifted with respect to the Rangeley Formation along the ductile Powder Hill fault, which also had a left-lateral component. Uplift continued into the early Mesozoic, producing the 2-kilometer-wide Campbell Hill fault zone, which is marked by northwest-dipping normal faults and dilational map-scale quartz bodies. Rare, undeformed Jurassic diabase dikes cut all older lithologies and structures. A second map is a compilation of joint orientations measured at all outcrops in the quadrangle. There is a great diversity of strike trends, with northeast perhaps being the most predominant.

  11. Bedrock Geologic Map of the Old Lyme Quadrangle, New London and Middlesex Counties, Connecticut

    Science.gov (United States)

    Walsh, Gregory J.; Scott, Robert B.; Aleinikoff, John N.; Armstrong, Thomas R.

    2009-01-01

    The bedrock geology of the Old Lyme quadrangle consists of Neoproterozoic and Permian gneisses and granites of the Gander and Avalon terranes, Silurian metasedimentary rocks of the Merrimack terrane, and Silurian to Devonian metasedimentary rocks of uncertain origin. The Avalon terrane rocks crop out within the Selden Neck block, and the Gander terrane rocks crop out within the Lyme dome. The Silurian to Devonian rocks crop out between these two massifs. Previous mapping in the Old Lyme quadrangle includes the work by Lawrence Lundgren, Jr. Lundgren's work provides an excellent resource for rock descriptions and detailed modal analyses of rock units that will not be duplicated in this current report. New research that was not covered in detail by Lundgren is the focus of this report and includes (1) evaluation of the rocks in the core of the Lyme dome in an effort to subdivide units in this area; (2) structural analysis of foliations and folds in and around the Lyme dome; (3) geochronology of selected units within the Lyme dome; and (4) analysis of joints and the fracture properties of the rocks.

  12. Geophysical borehole methods in fracture analysis of crystalline bedrock of the Loviisa site

    International Nuclear Information System (INIS)

    Rouhiainen, Pekka.

    1989-04-01

    The aim of this study is to develope interpretation methods to determine fracture porosity and directional properties of water filled fracture space in crystalline bedrock. Geophysical methods with high spatial resolution along the borehole are chosen for the study. This enables the analysis of individual fractures. The analyzed methods are the dipmeter, sonic log, and bed resolution density log. The spatial resolution of the sonic log is improved with a convolution filter. The proposed method for fracture aperture analysis utilizes peak values of anomalies. Equal area projection is used for visual presentation of the fracture porosity and directional properties of fracture space. A tensor presentation with probability correction is applied for matemathical presentation of fracture properties. The material for the study is from the investigations of the Loviisa nuclear power plant site in Finland. The results from the site reveal that fracture aperture is unevenly distributed. The fracture porosity tensor is strongly oriented to horizontal direction. Comparison with hydraulic tests indicated that the total fracture porosity is one or two orders of magnitude larger than the hydraulically determined effective flow porosity or kinematic porosity

  13. Effects of bedrock fractures on radionuclide transport near a vertical deposition hole for spent nuclear fuel

    International Nuclear Information System (INIS)

    Pulkkanen, V.-M.; Nordman, H.

    2011-12-01

    Effects of bedrock fractures on radionuclide transport near a vertical deposition hole for spent nuclear fuel are studied computationally. The studied fractures are both natural and excavation damage fractures. The emphasis is on the detailed modelling of geometry in 3D in contrast to the traditional radionuclide transport studies that often concentrate on chain decays, sorption, and precipitation at the expense of the geometry. The built computer model is used to assess the significance of components near a deposition hole for radionuclide transport and to estimate the quality of previously used modelling techniques. The results show nearly exponential decrease of radionuclide mass in the bentonite buffer when the release route is a thin natural fracture. The results also imply that size is the most important property of the tunnel section for radionuclide transport. In addition, the results demonstrate that the boundary layer theory can be used to approximate the release of radionuclides with certain accuracy and that a thin fracture in rock can be modelled, at least to a certain limit, by using a fracture with wider aperture but with same flow rate as the thin fracture. (orig.)

  14. Ground-water flow and recharge in the Mahomet Bedrock Valley Aquifer, east-central Illinois: A conceptual model based on hydrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Panno, S.V.; Hackley, K.C.; Cartwright, K.; Liu, C.L. (Illinois State Geological Survey, Champaign, IL (United States))

    1994-04-01

    Major-ion and isotopic analyses of ground water have been used to develop a conceptual model of flow and recharge to the Mahomet Bedrock Valley Aquifer (MVA). The MVA is composed of clean, permeable sands and gravels and forms a basal'' fill up to 60 m thick in a buried, west-trending bedrock valley. A thick succession of glacial tills, some containing interbedded lenses of sand and gravel, covers the MVA. Three regions within the MVA have hydrochemically distinct ground-water types. A fourth ground-water type was found at the confluence of the MVA and the Mackinaw Bedrock Valley Aquifer (MAK) to the west.

  15. Bedrock morphology and structure, upper Santa Cruz Basin, south-central Arizona, with transient electromagnetic survey data

    Science.gov (United States)

    Bultman, Mark W.; Page, William R.

    2016-10-31

    The upper Santa Cruz Basin is an important groundwater basin containing the regional aquifer for the city of Nogales, Arizona. This report provides data and interpretations of data aimed at better understanding the bedrock morphology and structure of the upper Santa Cruz Basin study area which encompasses the Rio Rico and Nogales 1:24,000-scale U.S. Geological Survey quadrangles. Data used in this report include the Arizona Aeromagnetic and Gravity Maps and Data referred to here as the 1996 Patagonia Aeromagnetic survey, Bouguer gravity anomaly data, and conductivity-depth transforms (CDTs) from the 1998 Santa Cruz transient electromagnetic survey (whose data are included in appendixes 1 and 2 of this report).Analyses based on magnetic gradients worked well to identify the range-front faults along the Mt. Benedict horst block, the location of possibly fault-controlled canyons to the west of Mt. Benedict, the edges of buried lava flows, and numerous other concealed faults and contacts. Applying the 1996 Patagonia aeromagnetic survey data using the horizontal gradient method produced results that were most closely correlated with the observed geology.The 1996 Patagonia aeromagnetic survey was used to estimate depth to bedrock in the upper Santa Cruz Basin study area. Three different depth estimation methods were applied to the data: Euler deconvolution, horizontal gradient magnitude, and analytic signal. The final depth to bedrock map was produced by choosing the maximum depth from each of the three methods at a given location and combining all maximum depths. In locations of rocks with a known reversed natural remanent magnetic field, gravity based depth estimates from Gettings and Houser (1997) were used.The depth to bedrock map was supported by modeling aeromagnetic anomaly data along six profiles. These cross sectional models demonstrated that by using the depth to bedrock map generated in this study, known and concealed faults, measured and estimated magnetic

  16. Mapping geological structures in bedrock via large-scale direct current resistivity and time-domain induced polarization tomography

    DEFF Research Database (Denmark)

    Rossi, Matteo; Olsson, Per-Ivar; Johansson, Sara

    2017-01-01

    An investigation of geological conditions is always a key point for planning infrastructure constructions. Bedrock surface and rock quality must be estimated carefully in the designing process of infrastructures. A large direct-current resistivity and time-domain induced-polarization survey has b...... been performed in Dalby, Lund Municipality, southern Sweden, with the aim of mapping lithological variations in bedrock. The geology at the site is characterised by Precambrian granitic gneisses and amphibolites, which are intensely deformed, fractured, and partly weathered. In addition......-polarization profiles. The direct-current resistivity and time-domain induced-polarization methodology proved to be a suitable technique for extensively mapping weathered zones with poor geotechnical characteristics and tectonic structures, which can lead to severe problems for infrastructure construction and....../or constitute risk zones for aquifer contamination....

  17. The impact of dynamic topography on the bedrock elevation and volume of the Pliocene Antarctic Ice Sheet

    Science.gov (United States)

    Austermann, Jacqueline; Pollard, David; Mitrovica, Jerry X.; Moucha, Robert; Forte, Alessandro M.; DeConto, Robert M.

    2015-04-01

    Reconstructions of the Antarctic ice sheet over long timescales (i.e. Myrs) require estimates of bedrock elevation through time. Ice sheet models have accounted, with varying levels of sophistication, for changes in the bedrock elevation due to glacial isostatic adjustment (GIA), but they have neglected other processes that may perturb topography. One notable example is dynamic topography, the deflection of the solid surface of the Earth due to convective flow within the mantle. Numerically predicted changes in dynamic topography have been used to correct paleo shorelines for this departure from eustasy, but the effect of such changes on ice sheet stability is unknown. In this study we use numerical predictions of time-varying dynamic topography to reconstruct bedrock elevation below the Antarctic ice sheet during the mid Pliocene warm period (~3 Ma). Moreover, we couple this reconstruction to a three-dimensional ice sheet model to explore the impact of dynamic topography on the evolution of the Antarctic ice sheet since the Pliocene. Our modeling indicates significant uplift in the area of the Transantarctic Mountains (TAM) and the adjacent Wilkes basin. This predicted uplift, which is at the lower end of geological inferences of uplift of the TAM, implies a lower elevation of the basin in the Pliocene. Relative to simulations that do not include dynamic topography, the lower elevation leads to a smaller Antarctic Ice Sheet volume and a more significant retreat of the grounding line in the Wilkes basin, both of which are consistent with offshore sediment core data. We conclude that reconstructions of the Antarctic Ice Sheet during the mid-Pliocene warm period should be based on bedrock elevation models that include the impact of both GIA and dynamic topography.

  18. Using Structure-from-Motion to Quantify Sediment Accumulation and Bedrock Erosion in a Debris-Flow Dominated Channel

    Science.gov (United States)

    Reitman, N. G.; Rengers, F.; Kean, J. W.

    2016-12-01

    One of the highest frequencies of observed debris flows in the US is located at the Chalk Cliffs in central Colorado. This high rate of debris-flow activity ( 3 per year) is supported by a similarly high rate of sediment supply from rock fall and ravel due to frost weathering of the highly-erodible, hydrothermally-altered quartz monzonite cliffs during the winter months. A first step toward understanding debris-flow initiation, and channel and hillslope evolution, is to quantify the magnitude and spatial distribution of sediment that accumulates by the end of the winter period. Here we test the ability of structure-from-motion photogrammetric surveys to produce high-resolution point clouds in order to quantify sediment deposition, and possibly bedrock erosion. We use point clouds obtained from surveys conducted in late September 2015 and early June 2016 to measure sediment deposition in a 42-m-long channel over one winter. All surveys are co-registered with control points (screws drilled into bedrock) measured in a local coordinate system with a total station. Point clouds derived from these surveys have average point densities >200,000 pts/m2, and accuracies within 2 cm. Initial analysis shows accumulation of 10-50 cm ( 10 m3) of unconsolidated loose sediment over eight months, providing ample material for debris-flow initiation during the following summer season. Sediment accumulated in a spatially-variable pattern dependent on existing channel-bottom bedrock topography. Future surveys are planned in order to measure bedrock erosion by debris flows and variation in sediment deposition rate through time. Our analysis indicates that photogrammetric surveys provide a high level of detail at low cost, and thus are a useful geomorphic monitoring tool that will ultimately lead to better understanding of the processes that contribute to debris-flow activity and landscape evolution.

  19. Surveying glacier bedrock topography with a helicopter-borne dual-polarization ground-penetrating radar system

    Science.gov (United States)

    Langhammer, L.; Rabenstein, L.; Schmid, L.; Bauder, A.; Schaer, P.; Maurer, H.

    2017-12-01

    Glacier mass estimations are crucial for future run-off projections in the Swiss Alps. Traditionally, ice thickness modeling approaches and ground-based radar transects have been the tools of choice for estimating glacier volume in high mountain areas, but these methods either contain high uncertainties or are logistically expensive and offer mostly only sparse subsurface information. We have developed a helicopter-borne dual-polarization ground-penetrating radar (GPR) system, which enhances operational feasibility in rough, high-elevation terrain and increases the data output per acquisition campaign significantly. Our system employs a prototype pulseEKKO device with two broadside 25-MHz antenna pairs fixed to a helicopter-towed wooden frame. Additionally attached to the system are a laser altimeter for measuring the flight height above ground, three GPS receivers for accurate positioning and a GoPro camera for obtaining visual images of the surface. Previous investigations have shown the significant impact of the antenna dipole orientation on the detectability of the bedrock reflection. For optimal results, the dipoles of the GPR should be aligned parallel to the strike direction of the surrounding mountain walls. In areas with a generally unknown bedrock topography, such as saddle areas or diverging zones, a dual-polarization system is particularly useful. This could be demonstrated with helicopter-borne GPR profiles acquired on more than 25 glaciers in the Swiss Alps. We observed significant differences in ice-bedrock interface visibility depending on the orientation of the antennas.

  20. Borehole environmental tracers for evaluating net infiltration and recharge through desert bedrock

    Science.gov (United States)

    Heilweil, V.M.; Solomon, D.K.; Gardner, P.M.

    2006-01-01

    Permeable bedrock aquifers in arid regions are being increasingly developed as water supplies, yet little is generally known about recharge processes and spatial and temporal variability. Environmental tracers from boreholes were used in this study to investigate net infiltration and recharge to the fractured Navajo Sandstone aquifer. Vadose zone tracer profiles at the Sand Hollow study site in southwestern Utah look similar to those of desert soils at other sites, indicating the predominance of matrix flow. However, recharge rates are generally higher in the Navajo Sandstone than in unconsolidated soils in similar climates because the sandstone matrix allows water movement but not root penetration. Water enters the vadose zone either as direct infiltration of precipitation through exposed sandstone and sandy soils or as focused infiltration of runoff. Net infiltration and recharge exhibit extreme spatial variability. High-recharge borehole sites generally have large amounts of vadose zone tritium, low chloride concentrations, and small vadose zone oxygen-18 evaporative shifts. Annual net-infiltration and recharge rates at different locations range from about 1 to 60 mm as determined using vadose zone tritium, 0 to 15 mm using vadose zone chloride, and 3 to 60 mm using groundwater chloride. Environmental tracers indicate a cyclical net-infiltration and recharge pattern, with higher rates earlier in the Holocene and lower rates during the late Holocene, and a return to higher rates during recent decades associated with anomalously high precipitation during the latter part of the 20th century. The slightly enriched stable isotopic composition of modern groundwater indicates this recent increase in precipitation may be caused by a stronger summer monsoon or winter southern Pacific El Nin??o storm track. ?? Soil Science Society of America.

  1. The analysis of the bedrock deformation in Olkiluoto using precise levelling measurements

    International Nuclear Information System (INIS)

    Saaranen, V.; Rouhiainen, P.; Suurmaeki, H.

    2014-01-01

    In order to research vertical bedrock deformations in the Olkiluoto area, Posiva Oy and the Finnish Geodetic Institute began monitoring with precise levelling in 2003. At the moment, the measuring plan includes a loop between the monitoring GPS stations around the island, a levelling line from the island to the mainland, levelling loops to ONKALO, the final disposal site, and VLJ, the low and intermediate level waste repository there. The levelling to the mainland has been performed every fourth year and the levelling of the GPS stations every second year. The micro loops (ONKALO and VLJ) have been measured annually. In this report, we use three-step method to research a vertical deformation of the Olkiluoto area. Firstly, the linear deformation rate in the area has been determined by the least squares adjustment of the levelling data. It varies from -0.2 mm/yr to +0.2 mm/yr. Secondly, local deformations have been analysed by comparing the height differences for different years. In this comparison a starting value for the yearly adjustment has been corrected for land uplift. Using this method the elevation changes are relative to the whole network. For a fixed benchmark, we correct its yearly deformation. Thirdly, the fault lines have been analysed by comparing the elevation changes between the successive benchmarks from one observation epoch to another. The results show that ONKALO and Lapijoki are in the subsidence area of the network, and VLJ has small uplift rate. On the island some deformations exist, but elevation difference from 2003 to 2011 is less than one millimetre at every benchmarks. The measurements in the Lapijoki-Olkiluoto line in 2003, 2007 and 2011 show that linear elevation change between the mainland and Olkiluoto island is a little since 2003. The elevation differences, from Olkiluoto to Lapijoki, measured in 2003 and 2011 differ less than one millimetre each other, but the 2007 observation differs three millimetres from the other measurements

  2. Conditioning geostatistical simulations of a heterogeneous paleo-fluvial bedrock aquifer using lithologs and pumping tests

    Science.gov (United States)

    Niazi, A.; Bentley, L. R.; Hayashi, M.

    2016-12-01

    Geostatistical simulations are used to construct heterogeneous aquifer models. Optimally, such simulations should be conditioned with both lithologic and hydraulic data. We introduce an approach to condition lithologic geostatistical simulations of a paleo-fluvial bedrock aquifer consisting of relatively high permeable sandstone channels embedded in relatively low permeable mudstone using hydraulic data. The hydraulic data consist of two-hour single well pumping tests extracted from the public water well database for a 250-km2 watershed in Alberta, Canada. First, lithologic models of the entire watershed are simulated and conditioned with hard lithological data using transition probability - Markov chain geostatistics (TPROGS). Then, a segment of the simulation around a pumping well is used to populate a flow model (FEFLOW) with either sand or mudstone. The values of the hydraulic conductivity and specific storage of sand and mudstone are then adjusted to minimize the difference between simulated and actual pumping test data using the parameter estimation program PEST. If the simulated pumping test data do not adequately match the measured data, the lithologic model is updated by locally deforming the lithology distribution using the probability perturbation method and the model parameters are again updated with PEST. This procedure is repeated until the simulated and measured data agree within a pre-determined tolerance. The procedure is repeated for each well that has pumping test data. The method creates a local groundwater model that honors both the lithologic model and pumping test data and provides estimates of hydraulic conductivity and specific storage. Eventually, the simulations will be integrated into a watershed-scale groundwater model.

  3. Age and Construction of Little Ambergris Cay Bedrock Rim, Southeastern Caicos Platform, British West Indies

    Science.gov (United States)

    Orzechowski, E. A.; Strauss, J. V.; Knoll, A. H.; Fischer, W. W.; Cantine, M.; Metcalfe, K.; Quinn, D. P.; Stein, N.; Gomes, M. L.; Grotzinger, H. M.; Lingappa, U.; O'Reilly, S. S.; Riedman, L. A.; Trower, L.; Grotzinger, J. P.

    2016-12-01

    The Caicos Platform's interior-platform ooid shoals and patch reef environments are unique modern examples of grain-rich carbonate settings. In July 2016, the Agouron Institute's Advanced Geobiology field course conducted a detailed study of Little Ambergris Cay, in the southeastern sector of the platform. The cay is fringed by a topographically high rim formed of amalgamated ridges of partially lithified fossiliferous grainstone and rudstone (i.e. beachrock conglomerate), that protects an interior basin dominated by microbial mats and mangroves. Tidal channels exchanging open platform waters with the interior basin breach the rim locally. We sampled and mapped the rim (using differential GPS) in order to examine its age, sedimentological characteristics, and faunal composition. Strata up to 2 meters above the present-day high tide mark form the rim, characterized by several carbonate lithofacies, including oolites with keystone vugs, high-angle trough cross bedding, seaward-dipping low angle stratification, bioturbation and fossiliferous lags, and rudstones composed of imbricated beachrock boulders. We interpret these facies as an upper shoreface to foreshore depositional setting dominated by local storm and eolian deposits. A distinct fossiliferous rudstone facies is dominated by mytilid bivalves, as well as Eustrombus, Conus, Oliva, and vermetid gastropods. X-ray powder diffraction analyses on fossil shells reveal both shells with pristine aragonite and shells with evidence of secondary calcite. Radiometric analyses of pristine aragonite material provide additional age constraints on these deposits. Understanding the formation of Little Ambergris Cay's bedrock deposits will provide important context for the island's geological history and geomorphology, aiding in our understanding of modern analogues for ancient interior platform depositional environments.

  4. Uranium and radon in private bedrock well water in Maine: geospatial analysis at two scales

    Science.gov (United States)

    Yang, Qiang; Smitherman, Paul; Hess, C.T.; Culbertson, Charles W.; Marvinney, Robert G.; Zheng, Yan

    2014-01-01

    In greater Augusta of central Maine, 53 out of 1093 (4.8%) private bedrock well water samples from 1534 km2 contained [U] >30 μg/L, the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) for drinking water; and 226 out of 786 (29%) samples from 1135 km2 showed [Rn] >4,000 pCi/L (148 Bq/L), the U.S. EPA’s Alternative MCL. Groundwater pH, calcite dissolution and redox condition are factors controlling the distribution of groundwater U but not Rn due to their divergent chemical and hydrological properties. Groundwater U is associated with incompatible elements (S, As, Mo, F, and Cs) in water samples within granitic intrusions. Elevated [U] and [Rn] are located within 5–10 km distance of granitic intrusions but do not show correlations with metamorphism at intermediate scales (100−101 km). This spatial association is confirmed by a high-density sampling (n = 331, 5–40 samples per km2) at local scales (≤10–1 km) and the statewide sampling (n = 5857, 1 sample per 16 km2) at regional scales (102–103 km). Wells located within 5 km of granitic intrusions are at risk of containing high levels of [U] and [Rn]. Approximately 48 800–63 900 and 324 000 people in Maine are estimated at risk of exposure to U (>30 μg/L) and Rn (>4000 pCi/L) in well water, respectively.

  5. Uranium and radon in private bedrock well water in Maine: geospatial analysis at two scales.

    Science.gov (United States)

    Yang, Qiang; Smitherman, Paul; Hess, C T; Culbertson, Charles W; Marvinney, Robert G; Smith, Andrew E; Zheng, Yan

    2014-04-15

    In greater Augusta of central Maine, 53 out of 1093 (4.8%) private bedrock well water samples from 1534 km(2) contained [U] >30 μg/L, the U.S. Environmental Protection Agency's (EPA) Maximum Contaminant Level (MCL) for drinking water; and 226 out of 786 (29%) samples from 1135 km(2) showed [Rn] >4,000 pCi/L (148 Bq/L), the U.S. EPA's Alternative MCL. Groundwater pH, calcite dissolution and redox condition are factors controlling the distribution of groundwater U but not Rn due to their divergent chemical and hydrological properties. Groundwater U is associated with incompatible elements (S, As, Mo, F, and Cs) in water samples within granitic intrusions. Elevated [U] and [Rn] are located within 5-10 km distance of granitic intrusions but do not show correlations with metamorphism at intermediate scales (10(0)-10(1) km). This spatial association is confirmed by a high-density sampling (n = 331, 5-40 samples per km(2)) at local scales (≤10(-1) km) and the statewide sampling (n = 5857, 1 sample per 16 km(2)) at regional scales (10(2)-10(3) km). Wells located within 5 km of granitic intrusions are at risk of containing high levels of [U] and [Rn]. Approximately 48 800-63 900 and 324 000 people in Maine are estimated at risk of exposure to U (>30 μg/L) and Rn (>4000 pCi/L) in well water, respectively.

  6. Evaluation of the ground surface Enthalpy balance from bedrock temperatures (Livingston Island, Maritime Antarctic

    Directory of Open Access Journals (Sweden)

    M. Ramos

    2009-05-01

    Full Text Available The annual evolution of the ground temperatures from Incinerador borehole in Livingston Island (South Shetlands, Antarctic is studied. The borehole is 2.4 m deep and is located in a massive quartzite outcrop with negligible water content, in the proximity of the Spanish Antarctic Station Juan Carlos I. In order to model the movement of the 0°C isotherm (velocity and maximum depth hourly temperature profiles from: (i the cooling periods of the frost season of 2000 to 2005, and (ii the warming periods of the thaw season of 2002–2003, 2003–2004 and 2004–2005, were studied. In this modelling approach, heat gains and losses across the ground surface are assumed to be the causes for the 0°C isotherm movement. A methodological approach to calculate the ground Enthalpy change based on the thermodynamic analysis of the ground during the cooling and warming periods is proposed. The Enthalpy change into the rock is equivalent to the heat exchange through the ground surface during each season, thus enabling to describe the interaction ground-atmosphere and providing valuable data for studies on permafrost and periglacial processes. The bedrock density and thermal conductivity are considered to be constant and initial isothermal conditions at 0°C are assumed (based in collected data and local meteorological conditions in this area to run the model in the beginning of each season. The final stages correspond to the temperatures at the end of the cooling and warming periods (annual minima and maxima. The application of this method avoids error propagation induced by the heat exchange calculations from multiple sensors using the Fourier method.

  7. Geologic constraints on bedrock river incision using the stream power law

    Science.gov (United States)

    Stock, Jonathan D.; Montgomery, David R.

    1999-03-01

    Denudation rate in unextended terranes is limited by the rate of bedrock channel incision, often modeled as work rate on the channel bed by water and sediment, or stream power. The latter can be generalized as KAmSn, where K represents the channel bed's resistance to lowering (whose variation with lithology is unknown), A is drainage area (a surrogate for discharge), S is local slope, and m and n are exponents whose values are debated. We address these uncertainties by simulating the lowering of ancient river profiles using the finite difference method. We vary m, n, and K to match the evolved profile as closely as possible to the corresponding modern river profile over a time period constrained by the age of the mapped paleoprofiles. We find at least two end-member incision laws, KA0.3-0.5S1 for Australian rivers with stable base levels and KfA0.1-0.2Sn for rivers in Kauai subject to abrupt base level change. The long-term lowering rate on the latter expression is a function of the frequency and magnitude of knickpoint erosion, characterized by Kf. Incision patterns from Japan and California could follow either expression. If they follow the first expression with m = 0.4, K varies from 10-7-10-6 m0.2/yr for granite and metamorphic rocks to 10-5-10-4 m0.2/yr for volcaniclastic rocks and 10-4-10-2 m0.2/yr for mudstones. This potentially large variation in K with lithology could drive strong variability in the rate of long-term landscape change, including denudation rate and sediment yield.

  8. Deep Impact: Effects of Mountaintop Mining on Surface Topography, Bedrock Structure, and Downstream Waters.

    Science.gov (United States)

    Ross, Matthew R V; McGlynn, Brian L; Bernhardt, Emily S

    2016-02-16

    Land use impacts are commonly quantified and compared using 2D maps, limiting the scale of their reported impacts to surface area estimates. Yet, nearly all land use involves disturbances below the land surface. Incorporating this third dimension into our estimates of land use impact is especially important when examining the impacts of mining. Mountaintop mining is the most common form of coal mining in the Central Appalachian ecoregion. Previous estimates suggest that active, reclaimed, or abandoned mountaintop mines cover ∼7% of Central Appalachia. While this is double the areal extent of development in the ecoregion (estimated to occupy impacts are far more extensive than areal estimates alone can convey as the impacts of mines extend 10s to 100s of meters below the current land surface. Here, we provide the first estimates for the total volumetric and topographic disturbance associated with mining in an 11 500 km(2) region of southern West Virginia. We find that the cutting of ridges and filling of valleys has lowered the median slope of mined landscapes in the region by nearly 10 degrees while increasing their average elevation by 3 m as a result of expansive valley filling. We estimate that in southern West Virginia, more than 6.4km(3) of bedrock has been broken apart and deposited into 1544 headwater valley fills. We used NPDES monitoring datatsets available for 91 of these valley fills to explore whether fill characteristics could explain variation in the pH or selenium concentrations reported for streams draining these fills. We found that the volume of overburden in individual valley fills correlates with stream pH and selenium concentration, and suggest that a three-dimensional assessment of mountaintop mining impacts is necessary to predict both the severity and the longevity of the resulting environmental impacts.

  9. Bedrock transport properties. Preliminary site description Simpevarp subarea - version 1.2

    International Nuclear Information System (INIS)

    Byegaard, Johan; Gustavsson, Eva; Tullborg, Eva-Lena; Berglund, Sten

    2005-06-01

    This report presents the site descriptive model of transport properties developed as a part of the Simpevarp 1.2 site description. The main parameters included in the model, referred to as retardation parameters, are the matrix porosity and diffusivity, and the matrix sorption coefficient K d . The model is based on the presently available site investigation data, mainly obtained from laboratory investigations of core samples from boreholes within the Simpevarp subarea, and on data from previous studies at the Aespoe Hard Rock Laboratory (Aespoe HRL). The modelling is a first attempt, based on limited data, to obtain a description of the retardation parameters. Further refinement of the model is foreseen when more data becomes available for future versions of the Simpevarp site description. The modelling work included descriptions of rock mass geology, the fractures and deformation zones, the hydrogeochemistry and also the available results from the site specific porosity, sorption and diffusivity measurements. The description of the transport related aspects of the data and models presented by other modelling disciplines is an important part of the transport description. In accordance with the strategy for the modelling of transport properties, the results are presented as a 'retardation model', in which a summary of the transport data for the different geological compartments is given. Concerning the major rock types, Aevroe granite, quartz monzodiorite and fine-grained dioritoid are identified as the rock types dominating the main rock domains identified and described in the site descriptive model of the bedrock geology. However, relatively large parts of the rock consist of altered rock and the open fracture frequency appears to be correlated to the altered/oxidised parts of the rock. This implies that transport in open fractures to a large extent takes place in the altered parts of the rock. For the fracture mineralogy, it is found that the hydraulically

  10. Digital bedrock mapping at the Geological Survey of Norway: BGS SIGMA tool and in-house database structure

    Science.gov (United States)

    Gasser, Deta; Viola, Giulio; Bingen, Bernard

    2016-04-01

    Since 2010, the Geological Survey of Norway has been implementing and continuously developing a digital workflow for geological bedrock mapping in Norway, from fieldwork to final product. Our workflow is based on the ESRI ArcGIS platform, and we use rugged Windows computers in the field. Three different hardware solutions have been tested over the past 5 years (2010-2015). (1) Panasonic Toughbook CE-19 (2.3 kg), (2) Panasonic Toughbook CF H2 Field (1.6 kg) and (3) Motion MC F5t tablet (1.5 kg). For collection of point observations in the field we mainly use the SIGMA Mobile application in ESRI ArcGIS developed by the British Geological Survey, which allows the mappers to store georeferenced comments, structural measurements, sample information, photographs, sketches, log information etc. in a Microsoft Access database. The application is freely downloadable from the BGS websites. For line- and polygon work we use our in-house database, which is currently under revision. Our line database consists of three feature classes: (1) bedrock boundaries, (2) bedrock lineaments, and (3) bedrock lines, with each feature class having up to 24 different attribute fields. Our polygon database consists of one feature class with 38 attribute fields enabling to store various information concerning lithology, stratigraphic order, age, metamorphic grade and tectonic subdivision. The polygon and line databases are coupled via topology in ESRI ArcGIS, which allows us to edit them simultaneously. This approach has been applied in two large-scale 1:50 000 bedrock mapping projects, one in the Kongsberg domain of the Sveconorwegian orogen, and the other in the greater Trondheim area (Orkanger) in the Caledonian belt. The mapping projects combined collection of high-resolution geophysical data, digital acquisition of field data, and collection of geochronological, geochemical and petrological data. During the Kongsberg project, some 25000 field observation points were collected by eight

  11. Review of the sorption of radionuclides on the bedrock of Haestholmen and on construction and backfill materials of a final repository for reactor wastes

    International Nuclear Information System (INIS)

    Kulmala, S.; Hakanen, M.

    1992-10-01

    Imatran Voima Oy (IVO) has plans to build a final repository for reactor wastes in the bedrock of the nuclear power plant site at Haestholmen, Loviisa. This report summarizes the sorption studies of radionuclides in Finnish bedrock performed at the Department of Radiochemistry, University of Helsinki. The values of mass distribution ratios, K d , and surface distribution ratios, K a ; of carbon, calsium, Zirconium, niobium, cobalt, nickel, strontium, cesium, uranium, plutonium, americium, thorium, chlorine, iodine and technetium are surveyed. Special attention is paid to the sorption data for construction and backfill materials of rector waste repository and the bedrock of Haestholmen. Safety assessment of a repository includes calculations of migration of the waste element in construction materials and backfill in the nearfield and in bedrock. Retardation by sorption of waste nuclides compared to groundwater flow is described by using distribution ratios between solid materials and water. (orig.)

  12. Thermal regime and potential bedrock weathering in alpine rockwalls of Austria: Results from eight years of monitoring (2006-2014)

    Science.gov (United States)

    Kellerer-Pirklbauer, Andreas; Wecht, Matthias

    2015-04-01

    Bedrock temperature at sites with a minor winter snow cover gives a good indication for the effects of air temperature anomalies on ground thermal conditions as well as for the intensity of near-surface physical weathering in bedrock. In this study we present results from an ongoing bedrock temperature monitoring program initiated in 2006. Within the framework of this program nine surface boreholes in rockwalls with different slope orientations and two additional boreholes at flat bedrock sites were drilled between August and September 2006 and subsequently instrumented. The altogether eleven rock temperature sites (RTS) are located in the alpine periglacial zone of the Austrian Alps at latitude 46°55' to 47°22' and longitude 12°44' to 14°41'. All RTS have been installed in metamorphic rock (5 x mica schist; 6 x gneiss) at elevations between 1960 and 2725 m asl (mean 2491 m asl.). Three temperature sensors (PT1000) have been inserted at each borehole site at vertical depths of 3, 10 and 30-40 cm. At each RTS the three sensors are connected to a 3-channel miniature temperature datalogger (MTD) manufactured by GeoPrecision, Germany. Our analysis focussed on (a) the variation of mean and extreme daily temperatures at the rock surface and at depth, (b) the variation of the daily temperature range, (c) the number of freeze-thaw-cycles (FTC) and (d) effective freeze-thaw cycles for frost shattering (eFTC), (e) the duration and intensity of freeze-thaw-cycles (DI-FTC), (f) the number of hours and days within the so-called frost-cracking-window (FCW), and effects of (g) aspect and (h) snow cover on the thermal regimes in the bedrock. Results show for instance that the number of FTC and eFTC varied substantially during the observation period at all eleven RTS and at all sensor depths. However, this variation differs from site to site related to snow cover condition, elevation and aspect. For instance, at one lower-elevated (2255 m asl) north exposed RTS the number of

  13. Erodibility of Titan ice bedrock constrained by laboratory measurements of ice strength and erosion by sediment impacts

    Science.gov (United States)

    Sklar, L. S.; Collins, G. C.; Litwin, K. L.; Polito, P. J.; Zygielbaum, B. R.

    2012-12-01

    Saturn's moon Titan has a remarkably earth-like surface morphology, with branching fluvial networks draining elevated terrain. A paucity of impact craters suggests fluvial dissection is active and that the pace of landscape evolution is rapid. A key limitation on modeling rates of incision by Titan's rivers of liquid methane has been a lack of information on the erodibility of water-ice bedrock at ultra-cold temperatures. Here we report results from laboratory measurements of ice resistance to tensile fracture and rates of erosion of Titan bedrock analogs by low-velocity sediment impacts. We apply these experimental results to modeling fluvial incision, and explore constraints on rates and frequency of channel cutting on Titan. We made test samples of polycrystalline ice with a narrow and wide size distribution of seed ice grains. For some samples we added solid impurities composed of basalt, urea, and ammonium-sulfate, to account for the possibility that Titan's ice bedrock also contains silicates from meteors, organic polymers derived from Titan's atmosphere, and ammonia-based compounds formed by cryovolcanism. The experiments were conducted in a walk-in freezer and environmental chamber, where we varied temperature between 260 and 110 K using dry ice and liquid nitrogen (LN). For terrestrial rocks, resistance to erosion by sediment impacts depends on the kinetic energy required to detach a unit volume, which has been shown to scale with the square of tensile strength. We measured the tensile strength of Titan bedrock analogs using the Brazilian splitting test and found that strength increases with decreasing temperature at 7 kPa/K, for all ice types tested. Ice at Titan temperatures is thus roughly twice as strong as at terrestrial conditions; ice is strengthened by increasing impurity concentrations, finer grain-size distributions, and lower porosity. To replicate erosion of ice bedrock by bedload sediment impacts, we filled a 55-gallon drum with various ice

  14. Quantitative extraction of the bedrock exposure rate based on unmanned aerial vehicle data and Landsat-8 OLI image in a karst environment

    Science.gov (United States)

    Wang, Hongyan; Li, Qiangzi; Du, Xin; Zhao, Longcai

    2017-12-01

    In the karst regions of southwest China, rocky desertification is one of the most serious problems in land degradation. The bedrock exposure rate is an important index to assess the degree of rocky desertification in karst regions. Because of the inherent merits of macro-scale, frequency, efficiency, and synthesis, remote sensing is a promising method to monitor and assess karst rocky desertification on a large scale. However, actual measurement of the bedrock exposure rate is difficult and existing remote-sensing methods cannot directly be exploited to extract the bedrock exposure rate owing to the high complexity and heterogeneity of karst environments. Therefore, using unmanned aerial vehicle (UAV) and Landsat-8 Operational Land Imager (OLI) data for Xingren County, Guizhou Province, quantitative extraction of the bedrock exposure rate based on multi-scale remote-sensing data was developed. Firstly, we used an object-oriented method to carry out accurate classification of UAVimages. From the results of rock extraction, the bedrock exposure rate was calculated at the 30 m grid scale. Parts of the calculated samples were used as training data; other data were used for model validation. Secondly, in each grid the band reflectivity of Landsat-8 OLI data was extracted and a variety of rock and vegetation indexes (e.g., NDVI and SAVI) were calculated. Finally, a network model was established to extract the bedrock exposure rate. The correlation coefficient of the network model was 0.855, that of the validation model was 0.677 and the root mean square error of the validation model was 0.073. This method is valuable for wide-scale estimation of bedrock exposure rate in karst environments. Using the quantitative inversion model, a distribution map of the bedrock exposure rate in Xingren County was obtained.

  15. Acceptance-criteria for the bedrock for deep geologic disposal of spent nuclear fuel. Proceedings from a seminar at Gothenburg University

    International Nuclear Information System (INIS)

    1995-11-01

    The seminar was directed to Nordic participants, and discussed disposal in the Nordic crystalline bedrock. Criteria for the bedrock should include: It should give durable mechanical protection for the engineered barriers; give a stable and favorable chemical environment for these barriers; have a low turnover of ground water in the near field; be easy to characterize; give favorable recipient-conditions; not have valuable minerals in workable quantities. These general criteria raise several questions coupled to the safety analysis: e.g. the need for geological, hydrological and geochemical parameters. Which data are missing, which are most difficult to find? What should the site characterization program look like to focus on factors that are of the highest importance according to the safety analysis. The demands on the conditions at a site need to be translated into quantitative criteria, which should be expressed as values that can be measured at the site or deduced from such measurements. These questions were discussed at the seminar, and 21 contributions from Finnish, Norwegian and Swedish participants are reported in these proceedings under the chapters: Coupling to the safety analysis; Methodology and criteria for site selection in a regional geoscientific perspective; Rock as a building material - prognosis and result; Geoscientific criteria for the bedrock at the repository - Mechanical protection; Geoscientific criteria for the bedrock at the repository - Low ground water turnover, chemically favorable and stable environment in the near field; Geoscientific criteria for the bedrock at the repository - Demands on the bedrock concerning the migration of radionuclides

  16. Effects of Gravel Bars on Nutrient Spiraling in Bedrock-Alluvium Streams

    Science.gov (United States)

    Iobst, B. R.; Carroll, E. P.; Furbish, D. J.

    2007-05-01

    The importance of the connection between nutrient transport and local stream geomorphology is becoming increasingly important. Studies have shown that the interconnectivity of nutrient cycles in the downstream direction is in part controlled by the distribution and size of gravel bars in low order streams, as hyporheic flow occurs dominantly through alternate and mid-channel gravel bars. For this investigation multiple gravel bars in a 3rd order bedrock-alluvium stream were studied to determine general relationships between nutrient spiraling and hyporheic flow. The first goal was to understand (1) the extent to which water moves through hyporheic zones and (2) the basic chemistry of the hyporheic water. The second part of the study was to understand how nutrients, notably nitrogen, are affected in their cycling by the relatively long residence times encountered in gravel bars during hyporheic flow. Wells were installed along a 600 m reach of Panther Creek, KY in selected bars, as well as in a secondary location involving a grid installation pattern in one large bar. Results have shown that hyporheic flow through gravel bars is an important factor in influencing stream chemistry. Background water chemistry surveys have shown that certain parameters, specifically ammonium and nitrogen concentrations vary downstream, and that the dominant control over these changes is gravel bar location. Rhodamine WT was used in field tracer tests to track the travel times of water through bars as well as partitioning of water between the open channel and hyporheic flows. Further tests will be conducted utilizing a stable isotope study to determine how nitrogen is affected by hyporheic flow, and what implications this has for nutrient transport. We expect results to show that the spacing and size of gravel bars is a dominant control in key nutrient spiraling parameters, namely uptake lengths and overall nitrogen cycling rates. This has implications for how natural systems will

  17. Attributes for NHDPlus Catchments (Version 1.1) in the Conterminous United States: Bedrock Geology

    Science.gov (United States)

    Wieczorek, Michael; LaMotte, Andrew E.

    2010-01-01

    This data set represents the area of bedrock geology types in square meters compiled for every catchment of NHDPlus for the conterminous United States. The source data set is the "Geology of the Conterminous United States at 1:2,500,000 Scale--A Digital Representation of the 1974 P.B. King and H.M. Beikman Map" (Schuben and others, 1994). The NHDPlus Version 1.1 is an integrated suite of application-ready geospatial datasets that incorporates many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). The NHDPlus includes a stream network (based on the 1:100,00-scale NHD), improved networking, naming, and value-added attributes (VAAs). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first widely used in New England, and thus referred to as "the New England Method." This technique involves "burning in" the 1:100,000-scale NHD and when available building "walls" using the National Watershed Boundary Dataset (WBD). The resulting modified digital elevation model (HydroDEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. Over the past two years, an interdisciplinary team from the U.S. Geological Survey (USGS), and the U.S. Environmental Protection Agency (USEPA), and contractors, found that this method produces the best quality NHD catchments using an automated process (USEPA, 2007). The NHDPlus dataset is organized by 18 Production Units that cover the conterminous United States. The NHDPlus version 1.1 data are grouped by the U.S. Geologic Survey's Major River Basins (MRBs, Crawford and others, 2006). MRB1, covering the New England and Mid-Atlantic River basins, contains NHDPlus Production Units 1 and 2. MRB2, covering the South Atlantic-Gulf and Tennessee River basins, contains NHDPlus Production Units 3 and 6. MRB3, covering the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy River basins, contains NHDPlus

  18. Geometric Reconstruction of Bedrock and Overlying Recent Deposits In An Intra-mountain Basin: The Clusone Basin (southern Alps, Italy)

    Science.gov (United States)

    Caielli, G.; Berra, F.

    Regione Lombardia (Direzione Generale Territorio e Urbanistica) and the National Research Council (CNR-IDPA Milano) acquired seismic reflection profiles in the Clu- sone basin (Middle Val Seriana, Southern Alps). In the study area, the bedrock is rep- resented by late Triassic carbonate units (Formazione di Castro, Dolomia Principale and coeval basinal facies, bordered northward by an important alpine fault) covered by a large amount of recent deposits that covers an area of more than 10 km2, with a maximum thickness of more than two hundreds meters, as documented by available well data. The aim of the seismic prospecting was to identify the sediments layering and the rock basement depth. The acquisition parameters were as follows: group in- terval 10 m; shot interval 5 m; geophone frequency 14 Hz; sample rate 1 ms; record length 2 s, energy source hydrapulse. The cable, with 120 channels, remained dur- ing all the experiment allowing reflection/refraction events acquisition. The data were processed by a standard procedure using PROMAX and SUNT5 processing codes. The statics were calculated starting from the refracted first arrivals using a two layer inversion based on least square optimisation. Standard seismic reflection processing was applied to obtain reflection images and it was integrated with seismic refraction data inversion. Seismic profiles allow to reconstruct both the main reflectors in the recent deposits and the geometry of the bedrock. The first results document a complex history in the drainage patterns of the Clusone basin, allowing to identify, in an intra- mountain basin, drainage directions that in some cases are different from the ones that can be observed today. The integration of well data and seismic profiles in this study of an intra-mountain basin allows on one side the identification of the bedrock geome- tries and, on the other, gives constrains for the reconstruction of the geomorphologic evolution of a sector of a mountain chain.

  19. Hydrogeologic Framework of Bedrock Units and Initial Salinity Distribution for a Simulation of Groundwater Flow for the Lake Michigan Basin

    Science.gov (United States)

    Lampe, David C.

    2009-01-01

    The U.S. Geological Survey is assessing groundwater availability in the Lake Michigan Basin. As part of the assessment, a variable-density groundwater-flow model is being developed to simulate the effects of groundwater use on water availability throughout the basin. The hydrogeologic framework for the Lake Michigan Basin model was developed by grouping the bedrock geology of the study area into hydrogeologic units on the basis of the functioning of each unit as an aquifer or confining layer within the basin. Available data were evaluated based on the areal extent of coverage within the study area, and procedures were established to characterize areas with sparse data coverage. Top and bottom altitudes for each hydrogeologic unit were interpolated in a geographic information system for input to the model and compared with existing maps of subsurface formations. Fourteen bedrock hydrogeologic units, making up 17 bedrock model layers, were defined, and they range in age from the Jurassic Period red beds of central Michigan to the Cambrian Period Mount Simon Sandstone. Information on groundwater salinity in the Lake Michigan Basin was compiled to create an input dataset for the variable-density groundwater-flow simulation. Data presented in this report are referred to as 'salinity data' and are reported in terms of total dissolved solids. Salinity data were not available for each hydrogeologic unit. Available datasets were assigned to a hydrogeologic unit, entered into a spatial database, and data quality was visually evaluated. A geographic information system was used to interpolate salinity distributions for each hydrogeologic unit with available data. Hydrogeologic units with no available data either were set equal to neighboring units or were vertically interpolated by use of values from units above and below.

  20. Upscaling Bedrock Erosion Laws from the Point to the Patch and from the Event to the Year

    Science.gov (United States)

    Beer, A. R.; Turowski, J. M.

    2017-12-01

    Bedrock erosion depends on the interactions between the bedload tools and cover effects. However, it is unclear (i) how well long-term calibrations of existing erosion models can predict individual erosion events, and (ii) whether at-a-point event calibrations can be spatio-temporally upscaled. Here, we evaluate the performance of at-a-point calibrated erosion models by scaling their erosional efficiency coefficients (k-factors). We use continuous measurements of water discharge and bedload transport at 1- minute resolution, supplemented by repeated sub-millimeter-resolution spatial erosion surveys of a concrete slab in a small Swiss pre-alpine stream. Our results confirm the linear dependency of bedrock abrasion on sediment flux under sediment-starved conditions integrated over space (the 0.2m2 slab surface) and time (20 months). The predictive quality of the commonly applied unit stream power (USP) model is strongly susceptible to bedload transport distribution, whereas the bedload-dependent tools-only model yields more reasonable results. Applying the fitted mean model k-factors to a 16-year, 1-minute-resolution time series of discharge and bedload transport shows that the excess USP model EUSP (which includes a discharge threshold for bedload transport) generally predicts cumulative erosion reasonably well. For exceptional events, however, the EUSP model fails to predict the resulting large erosion rates. Hence, for sediment-starved conditions, event-based erosion model calibration can be applied over larger spatio-temporal scales with stationary k-factors, if a discharge threshold for sediment transport is taken into account. The EUSP model is a surrogate to predict long-term erosion given average erosive events, but fails to capture large event erosion rates. Consequently, the erosion tendency during average erosive events is generally matched by overall EUSP modelling, but large and highly erosive events are underpredicted. In such, water discharge does not

  1. Proceedings of a seminar on sea level displacement and bedrock uplift, 10-11 June 2010, Pori, Finland

    International Nuclear Information System (INIS)

    Lipping, T.; Ikonen, A.T.K.

    2011-01-01

    This working report is the proceedings of a seminar on Sea level displacement and bedrock uplift held on 10-11 June 2010 in Pori, Finland. The seminar included invited oral presentations, as well as poster presentations, addressing the causes and mechanisms, observations, modelling and implications of the sea level change and crustal uplift still continuing after the last glaciation in the Baltic Sea region. In the proceedings, a total of 14 papers are included, in addition to foreword and a summary of seminar discussions. (orig.)

  2. Electrical resistivity dynamics beneath a fractured sedimentary bedrock riverbed in response to temperature and groundwater–surface water exchange

    Directory of Open Access Journals (Sweden)

    C. M. Steelman

    2017-06-01

    Full Text Available Bedrock rivers occur where surface water flows along an exposed rock surface. Fractured sedimentary bedrock can exhibit variable groundwater residence times, anisotropic flow paths, and heterogeneity, along with diffusive exchange between fractures and rock matrix. These properties of the rock will affect thermal transients in the riverbed and groundwater–surface water exchange. In this study, surface electrical methods were used as a non-invasive technique to assess the scale and temporal variability of riverbed temperature and groundwater–surface water interaction beneath a sedimentary bedrock riverbed. Conditions were monitored at a semi-daily to semi-weekly interval over a full annual period that included a seasonal freeze–thaw cycle. Surface electromagnetic induction (EMI and electrical resistivity tomography (ERT methods captured conditions beneath the riverbed along a pool–riffle sequence of the Eramosa River in Canada. Geophysical datasets were accompanied by continuous measurements of aqueous specific conductance, temperature, and river stage. Time-lapse vertical temperature trolling within a lined borehole adjacent to the river revealed active groundwater flow zones along fracture networks within the upper 10 m of rock. EMI measurements collected during cooler high-flow and warmer low-flow periods identified a spatiotemporal riverbed response that was largely dependent upon riverbed morphology and seasonal groundwater temperature. Time-lapse ERT profiles across the pool and riffle sequence identified seasonal transients within the upper 2 and 3 m of rock, respectively, with spatial variations controlled by riverbed morphology (pool versus riffle and dominant surficial rock properties (competent versus weathered rock rubble surface. While the pool and riffle both exhibited a dynamic resistivity through seasonal cooling and warming cycles, conditions beneath the pool were more variable, largely due to the formation of river

  3. Lithological effects in soil formation and soil slips on weathering-limited slopes underlain by granitic bedrocks in Japan

    OpenAIRE

    Wakatsuki, Tsuyoshi; Matsukura, Yukinori

    2008-01-01

    Soil slips occur every few years due to heavy rains on biotite granite (Gb) and hornblende biotite granite (Ghb) slopes in the Taga Mountains, Ibaraki Prefecture, Japan. The occurrence density of soil slips per unit area is 2.7 times greater in the Gb slopes than that in Ghb slopes. We examined the chemical, mineral, physical, and mechanical properties of two soil profiles on soil-slip scars in these slopes to study the effect of bedrock mineral composition on the density of soil slips. For a...

  4. Deglaciation-induced uplift and seasonal variations patterns of bedrock displacement in Greenland ice sheet margin observed from GPS, GRACE and InSAR

    Science.gov (United States)

    Lu, Q.; Amelung, F.; Wdowinski, S.

    2017-12-01

    The Greenland ice sheet is rapidly shrinking with the fastest retreat and thinning occurring at the ice sheet margin and near the outlet glaciers. The changes of the ice mass cause an elastic response of the bedrock. Theoretically, ice mass loss during the summer melting season is associated with bedrock uplift, whereas increasing ice mass during the winter months is associated with bedrock subsidence. Here we examine the annual changes of the vertical displacements measured at 37 GPS stations and compare the results with Greenland drainage basins' gravity from GRACE. We use both Fourier Series (FS) analysis and Cubic Smoothing Spline (CSS) method to estimate the phases and amplitudes of seasonal variations. Both methods show significant differences seasonal behaviors in southern and northern Greenland. The average amplitude of bedrock displacements (3.29±0.02mm) in south Greenland is about 2 times larger than the north (1.65±0.02mm). The phase of bedrock maximum uplift (November) is considerably consistent with the time of minimum ice mass load in south Greenland (October). However, the phase of bedrock maximum uplift in north Greenland (February) is 4 months later than the minimum ice mass load in north Greenland basins (October). In addition, we present ground deformation near several famous glaciers in Greenland such as Petermann glacier and Jakobshavn glacier. We process InSAR data from TerraSAR-X and Sentinel satellite, based on small baseline interferograms. We observed rapid deglaciation-induced uplift and seasonal variations on naked bedrock near the glacier ice margin.

  5. Evaluation of Rehabilitation Efficiency of Clogged wells drilled in fractured bedrock and alluvium

    Science.gov (United States)

    Lee, C.; Hamm, S.; Lee, J.; Ok, S.; Han, S.; Choo, C.; Kim, M.

    2011-12-01

    In Korea, more than one million of groundwater wells have been developed since 1990s. However, the groundwater wells have not been properly managed. Moreover, the importance of well maintenance and well rehabilitation has not been well recognized. In this circumstance, groundwater wells are usually terminated in 20-year operation due to well clogging, groundwater pollution, land use change, etc. which are originated from physical, chemical, biological, and artificial changes of and around the wells. The clogged state of the wells with diminished amount down to 80-85% can be ameliorated by various rehabilitation techniques as increasing discharge amount as well as extending the durability of the wells. In European countries and the USA, rehabilitation techniques of the clogged wells have been developed with understanding the cause and prevention of well bore clogging since 1990s. In recent years, the Korean Ministry of Environment (KME) recognized the importance of well rehabilitation. Under the support of the KME, this study evaluated the efficieny of rehabilitation using air surging, high-pressure water injection, brush & air surging, and explosive charge methods as applying to seven wells installed in fractured granite of Mt. Geumjeong and one well drilled in alluvial deposit of the Jeungsan-Ri area, Gyeongnam Province in the southeastern part of Korea. Hydraulic conductivity was estimated by using slug and pumping tests before and after well rehabilitation in order to assess physical, chemical, and biological changes of the wells. Hydraulic conductivity and pumping capacity of fractured bedrock are closely related to fracture characteristics such as fracture aperture, frequency, length, orientation, dip angle, interconnectivity, plane features, and filling materials. The evolution of clogging and filling of materials on and around the well makes decrease hydraulic conductivity and pumping capacity of the well. In this study, in addition of hydraulic conductivity

  6. Biogenic processes in crystalline bedrock fractures indicated by carbon isotope signatures of secondary calcite

    International Nuclear Information System (INIS)

    Sahlstedt, Elina; Karhu, Juha A.; Pitkänen, Petteri; Whitehouse, Martin

    2016-01-01

    Variation in 13 C/ 12 C-isotope ratios of fracture filling calcite was analyzed in situ to investigate carbon sources and cycling in fractured bedrock. The study was conducted by separating sections of fracture fillings, and analyzing the 13 C/ 12 C-ratios with secondary ion mass spectrometry (SIMS). Specifically, the study was aimed at fillings where previously published sulfur isotope data indicated the occurrence of bacterial sulfate reduction. The results showed that the δ 13 C values of calcite were highly variable, ranging from −53.8‰ to +31.6‰ (VPDB). The analysis also showed high variations within single fillings of up to 39‰. The analyzed calcite fillings were mostly associated with two calcite groups, of which Group 3 represents possible Paleozoic fluid circulation, based on comparison with similar dated coatings within the Baltic Shield and the succeeding Group 1–2 fillings represent late-stage, low temperature mineralization and are possibly late Paleozoic to Quaternary in age. Both generations were associated with pyrite with δ 34 S values indicative of bacterial sulfate reduction. The δ 13 C values of calcite, however, were indicative of geochemical environments which were distinct for these generations. The δ 13 C values of Group 3 calcite varied from −22.1‰ to +11‰, with a distinct peak at −16‰ to −12‰. Furthermore, there were no observable depth dependent trends in the δ 13 C values of Group 3 calcite. The δ 13 C values of Group 3 calcite were indicative of organic matter degradation and methanogenesis. In contrast to the Group 3 fillings, the δ 13 C values of Group 1–2 calcite were highly variable, ranging from −53.8‰ to +31.6‰ and they showed systematic variation with depth. The near surface environment of <30 m (bsl) was characterized by δ 13 C values indicative of degradation of surface derived organic matter, with δ 13 C values ranging from −30.3‰ to −5.5‰. The intermediate depth of

  7. A model of three-dimensional topographic stresses with implications for bedrock fractures, surface processes, and landscape evolution

    Science.gov (United States)

    Moon, S.; Perron, J. T.; Martel, S. J.; Holbrook, W. S.; St. Clair, J.

    2017-04-01

    Bedrock fractures influence the rates of surface processes that drive landscape evolution and are in turn influenced by landforms that perturb ambient tectonic and gravitational stress fields. In this modeling study, we examine how three-dimensional topography and tectonic stress regimes influence elastic stress fields and bedrock fracture patterns beneath Earth's surface. We illustrate general effects of landform orientation and of tectonic stress magnitude and anisotropy using boundary element models of stresses beneath synthetic elongated ridges with different aspect ratios. We then examine the more detailed effects of landform shape using natural landscapes in Colorado and South Carolina. We show that the stress field is most sensitive to topographic perturbations if the most compressive horizontal tectonic stress is oriented perpendicular to the long axis of elongated landforms such as ridges and valleys and that topographic stress perturbations are most pronounced beneath landforms with higher mean curvatures, such as channel junctions and ridge crests. The shape of a predicted fracture-rich zone in the subsurface depends mainly on the orientation of landforms relative to the most compressive horizontal tectonic stress direction and a dimensionless ratio that expresses the relative magnitudes of topographic stresses associated with horizontal tectonic compression and topographic relief. Variations in this dimensionless ratio can also change the predicted orientations of potential opening-mode fracture planes. We use these model results to illustrate how topographic perturbations of three-dimensional tectonic and gravitational stresses could influence landscape evolution by altering the rates and spatial heterogeneity of surface processes and groundwater flow.

  8. Feasibility study and technical proposal for the use of microseismic methods in the long-term observation of bedrock stability

    International Nuclear Information System (INIS)

    Saari, J.

    1995-04-01

    Recent geodetic and seismological studies have paid attention to the slow deformation occurring in the Fennoscandian Shield. On the basis of these studies, together with in-situ stress measurements, the idea has been put forth that horizontal movement can be even greater than vertical movement. Local seismotectonics has importance in relation to the predictions of the long-term stability of the bedrock at the final disposal site. Potential direct and - what in Finland is more likely - indirect effects on the vault are due to local earthquakes of creep. The direct effects on the repository include rock vibration and displacement on an increasing fault. The indirect effects are changes in the surrounding structure, in the stress field, in the groundwater table, pressure, flux and chemistry. The block movements are controlled mainly by the network of fracture zones. The report deals with the possibilities to monitor by seismic methods slow movements occurring in the bedrock at the local level. The report includes descriptions of instrumentation for recording microearthquakes, the seismic network and an interpretation of the observations. The potential sites for disposal (Kuhmo, Aeaenekoski, Eurajoki) are compared in relation to seismic monitoring. Also the experiences of other investigations and a proposal for microearthquake investigations as well as of prospective developments within monitoring are presented. (28 refs., 17 figs.)

  9. Structure and geological evolution of the bedrock at southern Satakunta, SW Finland

    International Nuclear Information System (INIS)

    Paulamaeki, S.; Paananen, M.; Elo, S.

    2002-02-01

    The southern Satakunta area lies on the west coast of Finland, mainly covering the mainland (with main towns Pori and Rauma), but also including the coastal archipelago and part of the Bothnian Sea. Near the centre of the area lies the island of Olkiluoto, on which Finland's site for a deep repository for spent nuclear fuel is located. The purpose of the present report is to compile and interpret all available geological and geophysical data relevant to understanding the regional geological setting of the Olkiluoto site. The area described is covered by four 1:100 000 scale geological map sheets, published by the Geological Survey of Finland, which, together with low-altitude aeromagnetic maps, provide the basis for a new 1:250 000 geological map compilation. This shows that the bedrock of southern Satakunta can be subdivided into three main zones: a pelitic migmatite belt in the southwest, a central, NW-SE trending area of sandstone, and a psammitic migmatite belt in the northeast. The migmatite belts formed during the Svecofennian orogeny, 1900-1800 Ma ago (Palaeoproterozoic). The sandstone area is the remnant of an alluvial basin, preserved now in a NW-SE trending graben, bounded on both sides by normal fault zones. The sandstones are thought to be at least 1400-1300 Ma old (Mesoproterozoic), and they are cut by Postjotnian olivine diabase dykes, 1270-1250 Ma in age. The Svecofennian migmatite belts show a complex history of formation, with various phases of anatexis/metamorphism, deformation and intrusion. In the pelitic migmatite belt, in which the Olkiluoto site is situated, four phases of ductile deformation (D-D4) and two phases of regional highT/lowP metamorphism and migmatite formation can be recognised, together with synorogenic (tonalite, granodiotite) and late orogenic ( potassium granite) intrusions. Subsequently, this very heterogeneous complex was intruded by anorogenic rapakivi granites, with ages 1580-1550 Ma. One pluton, the Eurajoki stock

  10. Structure and geological evolution of the bedrock at southern Satakunta, SW Finland

    Energy Technology Data Exchange (ETDEWEB)

    Paulamaeki, S.; Paananen, M.; Elo, S. [Geological Survey of Finland (Finland)

    2002-02-01

    The southern Satakunta area lies on the west coast of Finland, mainly covering the mainland (with main towns Pori and Rauma), but also including the coastal archipelago and part of the Bothnian Sea. Near the centre of the area lies the island of Olkiluoto, on which Finland's site for a deep repository for spent nuclear fuel is located. The purpose of the present report is to compile and interpret all available geological and geophysical data relevant to understanding the regional geological setting of the Olkiluoto site. The area described is covered by four 1:100 000 scale geological map sheets, published by the Geological Survey of Finland, which, together with low-altitude aeromagnetic maps, provide the basis for a new 1:250 000 geological map compilation. This shows that the bedrock of southern Satakunta can be subdivided into three main zones: a pelitic migmatite belt in the southwest, a central, NW-SE trending area of sandstone, and a psammitic migmatite belt in the northeast. The migmatite belts formed during the Svecofennian orogeny, 1900-1800 Ma ago (Palaeoproterozoic). The sandstone area is the remnant of an alluvial basin, preserved now in a NW-SE trending graben, bounded on both sides by normal fault zones. The sandstones are thought to be at least 1400-1300 Ma old (Mesoproterozoic), and they are cut by Postjotnian olivine diabase dykes, 1270-1250 Ma in age. The Svecofennian migmatite belts show a complex history of formation, with various phases of anatexis/metamorphism, deformation and intrusion. In the pelitic migmatite belt, in which the Olkiluoto site is situated, four phases of ductile deformation (D-D4) and two phases of regional highT/lowP metamorphism and migmatite formation can be recognised, together with synorogenic (tonalite, granodiotite) and late orogenic ( potassium granite) intrusions. Subsequently, this very heterogeneous complex was intruded by anorogenic rapakivi granites, with ages 1580-1550 Ma. One pluton, the Eurajoki stock

  11. Comparison of mineral weathering and biomass nutrient uptake in two small forested watersheds underlain by quartzite bedrock, Catoctin Mountain, Maryland, USA

    Science.gov (United States)

    Rice, Karen; Price, Jason R.

    2014-01-01

    To quantify chemical weathering and biological uptake, mass-balance calculations were performed on two small forested watersheds located in the Blue Ridge Physiographic Province in north-central Maryland, USA. Both watersheds, Bear Branch (BB) and Fishing Creek Tributary (FCT), are underlain by relatively unreactive quartzite bedrock. Such unreactive bedrock and associated low chemical-weathering rates offer the opportunity to quantify biological processes operating within the watershed. Hydrologic and stream-water chemistry data were collected from the two watersheds for the 9-year period from June 1, 1990 to May 31, 1999. Of the two watersheds, FCT exhibited both higher chemical-weathering rates and biomass nutrient uptake rates, suggesting that forest biomass aggradation was limited by the rate of chemical weathering of the bedrock. Although the chemical-weathering rate in the FCT watershed was low relative to the global average, it masked the influence of biomass base-cation uptake on stream-water chemistry. Any differences in bedrock mineralogy between the two watersheds did not exert a significant influence on the overall weathering stoichiometry. The difference in chemical-weathering rates between the two watersheds is best explained by a larger proportion of reactive phyllitic layers within the bedrock of the FCT watershed. Although the stream gradient of BB is about two-times greater than that of FCT, its influence on chemical weathering appears to be negligible. The findings of this study support the biomass nutrient uptake stoichiometry of K1.0Mg1.1Ca0.97 previously determined for the study site. Investigations of the chemical weathering of relatively unreactive quartzite bedrock may provide insight into critical zone processes.

  12. Landslide-induced weathering: insight from a deep bedrock tunnel in Taiwan and implications for the carbon cycle

    Science.gov (United States)

    Martin, C. E.; Galy, A.; Calmels, D.; Hovius, N.; Bickle, M.; Chen, M.

    2012-12-01

    We present new groundwater chemistry data from inside a 520 m-long, un-cased bedrock tunnel in Taroko Gorge, Taiwan. The tunnel cuts through a ~ 250 m ridge of steeply-dipping meta-sediments (schists and marbles) and exhibits water flow characteristic of deep groundwater and slow surface runoff as defined by Calmels et al. (2011). For comparison, surface runoff from the tunnel face is also presented. In October 2009, catastrophic failure resulted in a landslide, removing ~ 10 m-deep of bedrock from the entire ridge face directly above the tunnel entrance. Groundwater was collected from several drip sites in September 2009 and from the same drip sites in May, June, July and August 2010. The chemistry of the water dripping close to the tunnel entrance disrupted by the landslide implies that the post-landslide groundwater was from a meteoric source with negligible evapotranspiration demonstrating that the geomorphic perturbation allowed for the relatively rapid flushing of underlying bedrock fractures. The drop in [Cl-] of ~ 60 % was associated with a rise in the [SO42-] by a factor of ~ 4 and a positive shift in δ13C of the dissolved inorganic carbon (DIC) of ~ 12 ‰. This could imply that weathering products in the fresh post-landslide groundwater resulted from sulphuric acid weathering associated with a rise in the carbonate-derived DIC. The rise in the [SO42-] suggests that the landslide-induced exposure of fresh mineral surfaces resulted in the relatively rapid oxidation of pyrite, generating sulphuric acid, which then acted as the primary weathering agent. Given that [Ca2+] and [HCO3-] remained constant, secondary carbonate precipitation also took place and the rise in the [Na+] by a factor of >7 associated with a rise in [Mg2+] and [K+] suggest that silicate dissolution had also been enhanced by the oxidation of pyrite. These results imply that landslides provide a mechanism for weathering in the deep critical zone, which in this case constitutes a net output

  13. Microtopographic evolution of mineral surfaces as a tool to identify and date young fault scarps in bedrock

    Science.gov (United States)

    Mayer, Larry; Rakovan, John; Rufe, Eric

    2000-04-01

    Faulting that results in surface ruptures through bedrock can be particularly difficult to date. For example, stratigraphic control on the age of faulting, based on the age of the bedrock, often leaves unacceptably large uncertainty on the age of the faulting. From a paleoseismological perspective, there is a clear need to determine if a bedrock fault scarp is actually a young feature. For young fault ruptures that create fresh mineral surfaces, analysis of microtopography developed by weathering of the mineral surface may provide a quantifiable method for determining the fault age. The direct quantitative measurement of mineral surface microtopography using Atomic Force Microscopy affords a novel method to study the rupture ages of active faults. The method for using microtopographic evolution of mineral surfaces depends on three conditions. The first condition is that freshly exposed mineral cleavage surfaces, which can be described geometrically as planes, are formed during a rupture event. The formation of these fresh surfaces is analogous to the initiation of a weathering 'clock' that defines time t=0. Following cleavage formation dissolution of the planar mineral surface occurs. The rate of dissolution for a mineral species under given climatic conditions, governs the rate of mineral surface alteration. Thus as dissolution proceeds, the roughness of the mineral surface increases. We suggest that the progression of microtopographic roughness over time, which can be estimated by computing quantitative statistics derived from digital mineral surface topography, will systematically vary until a steady state surface topography is reached. The fractal dimension, Df, is one such measure of surface roughness where, Df at time t=0 is 2. The dissolution of the mineral surface increases the fractal dimension as the removal of material proceeds. We posit that somewhere between Df=2 and Df=3, the microtopography reaches a steady state. Therefore, in the pre-steady state

  14. Regional Deformation of the Southern Puna Plateau, Central Andes, Recorded by Basin Evolution and Bedrock Exhumation History

    Science.gov (United States)

    Zhou, R.; Schoenbohm, L. M.; Sobel, E. R.; Carrapa, B.; Davis, D. W.; Glodny, J.; Stockli, D. F.

    2015-12-01

    The regional deformation history of the southern Puna Plateau remains poorly constrained but is key to understanding the growth and dynamics of the central Andes, an important example of orogeny along a non-collisional plate boundary. Several lines of evidence lead us to propose that the southern Puna Plateau was occupied by an uninterrupted sedimentary basin during the late Eocene to early Oligocene (~38-28 Ma). First, oldest strata in the Antofagasta de la Sierra region (SW Puna) and the Pasto Ventura region (SE Puna) both contain little volcanic material, suggesting they predate the most recent arc activity at ~28 Ma. Second, detrital zircons from the Antofagasta de la Sierra region yield youngest U-Pb ages of ~39 Ma and detrital apatites from the Pasto Ventura region yield youngest fission-track ages of ~38 Ma, giving a maximum depositional age. Third, provenance analysis reveals a single, western source for the Antofagasta de la Sierra region (SW Puna) and dual, eastern and western sources for the Pasto Ventura region (SE Puna), supporting the presence of a regional basin. This regional basin was disrupted and compartmentalized by uplift of ~N-S trending bedrock ranges starting as early as in late Oligocene time. Bedrock samples from the eastern foot of the Sierra de Calalaste (SW Puna) yield an apatite (U-Th-Sm)/He age of 19.9±2.0 Ma, consistent with modeled apatite fission-track data that show onset of exhumation at ~25-20 Ma. Modeling of apatite fission-track and (U-Th-Sm)/He data shows that the Sierra Laguna Blanca (SE Puna) experienced exhumation at ~15-10 Ma, the youngest bedrock exhumation documented in the plateau region, implying that deformation and erosion of basement-bounding structures continued into the middle Miocene. We suggest that the post-late Eocene regional deformation history of the southern Puna Plateau documents an important dynamic shift from flexure-controlled foreland dynamics to flexure-limited broken foreland dynamics during the

  15. Use of Geodetic Laser Scanning to Evaluate the Curvature of Bedrock Surfaces in an Investigation of Sheeting Joint Formation

    Science.gov (United States)

    Martel, S. J.; Mitchell, K.

    2007-12-01

    We are using aerial and tripod-mounted geodetic laser scanning (GLS) data, together with photography and large-scale geologic mapping, to investigate the formation of sheeting joints in Yosemite National Park. Sheeting joints are opening-mode fractures that form subparallel to the topography, and over broad areas in Yosemite they define the bedrock surface. Rock slabs bounded by sheeting joints superficially resemble the layers of an onion. Our hypothesis is that sheeting joints form where a tensile stress normal to the topographic surface exists in the shallow subsurface. This condition is met where k2 P22 + k3 P33 > γ cosβ, where k2 and k3 are the principal curvatures of the bedrock surface, P22 and P33 are the corresponding normal stresses parallel to the principal stresses, γ is the unit weight of the rock, and β is the slope angle. Sheeting joints are predicted where at least one of the principal curvatures is sufficiently convex (negative) and the corresponding normal stress is sufficiently compressive (negative). We use aerial GLS data with a vertical resolution of ~10 cm and a point spacing of ~1 m to measure the slope and curvature of the bedrock surface at the scale of a ridge or valley. We use tripod-mounted GLS data with a point spacing of ~5 cm, large-scale geologic mapping, and photographs to detect steps between consecutive sheeting joints, with the step height giving the sheet joint spacing. Outcrops hosting sheeting joints have a stair-step appearance with a distinctive curvature signature: high convex curvature at the top of a step, and high concave curvature at the step bottom. Steps between sheeting joints with a spacing of less than a meter or so are difficult to detect using the aerial GLS data. Apparently the interpolation of aerial data onto a grid, necessary for our curvature codes, and the smoothing of gridded data to filter out trees compromises the value of the aerial GLS data in detecting the step edges, even though the vertical

  16. The SPACE 1.0 model: a Landlab component for 2-D calculation of sediment transport, bedrock erosion, and landscape evolution

    Science.gov (United States)

    Shobe, Charles M.; Tucker, Gregory E.; Barnhart, Katherine R.

    2017-12-01

    Models of landscape evolution by river erosion are often either transport-limited (sediment is always available but may or may not be transportable) or detachment-limited (sediment must be detached from the bed but is then always transportable). While several models incorporate elements of, or transition between, transport-limited and detachment-limited behavior, most require that either sediment or bedrock, but not both, are eroded at any given time. Modeling landscape evolution over large spatial and temporal scales requires a model that can (1) transition freely between transport-limited and detachment-limited behavior, (2) simultaneously treat sediment transport and bedrock erosion, and (3) run in 2-D over large grids and be coupled with other surface process models. We present SPACE (stream power with alluvium conservation and entrainment) 1.0, a new model for simultaneous evolution of an alluvium layer and a bedrock bed based on conservation of sediment mass both on the bed and in the water column. The model treats sediment transport and bedrock erosion simultaneously, embracing the reality that many rivers (even those commonly defined as bedrock rivers) flow over a partially alluviated bed. SPACE improves on previous models of bedrock-alluvial rivers by explicitly calculating sediment erosion and deposition rather than relying on a flux-divergence (Exner) approach. The SPACE model is a component of the Landlab modeling toolkit, a Python-language library used to create models of Earth surface processes. Landlab allows efficient coupling between the SPACE model and components simulating basin hydrology, hillslope evolution, weathering, lithospheric flexure, and other surface processes. Here, we first derive the governing equations of the SPACE model from existing sediment transport and bedrock erosion formulations and explore the behavior of local analytical solutions for sediment flux and alluvium thickness. We derive steady-state analytical solutions for

  17. Mineralogical sources of groundwater fluoride in Archaen bedrock/regolith aquifers: Mass balances from southern India and north-central Sri Lanka

    Directory of Open Access Journals (Sweden)

    B.M. Hallett

    2015-09-01

    New hydrological insights for the region: An estimate of weathering duration for the in situ regolith in Andhra Pradesh, 250–380 Ka, is close to a previous estimate for southern India. Partial or total destruction of the primary F-bearing bedrock minerals and consistent depletion of F in the remnant minerals result in a much reduced total F content in the regolith. Leaching experiments and field relationships, however, indicate a greater potential for F mobilisation to groundwater from the regolith than the bedrock. Schemes for managed aquifer recharge should beware the risk of mobilising additional F to groundwater.

  18. Water resources of Rockland County, New York, 2005-07, with emphasis on the Newark Basin Bedrock Aquifer

    Science.gov (United States)

    Heisig, Paul M.

    2011-01-01

    Concerns over the state of water resources in Rockland County, NY, prompted an assessment of current (2005-07) conditions. The investigation included a review of all water resources but centered on the Newark basin aquifer, a fractured-bedrock aquifer over which nearly 300,000 people reside. Most concern has been focused on this aquifer because of (1) high summer pumping rates, with occasional entrained-air problems and an unexplained water-level decline at a monitoring well, (2) annual withdrawals that have approached or even exceeded previous estimates of aquifer recharge, and (3) numerous contamination problems that have caused temporary or long-term shutdown of production wells. Public water supply in Rockland County uses three sources of water in roughly equal parts: (1) the Newark basin sedimentary bedrock aquifer, (2) alluvial aquifers along the Ramapo and Mahwah Rivers, and (3) surface waters from Lake DeForest Reservoir and a smaller, new reservoir supply in the Highlands part of the county. Water withdrawals from the alluvial aquifer in the Ramapo River valley and the Lake DeForest Reservoir are subject to water-supply application permits that stipulate minimum flows that must be maintained downstream into New Jersey. There is a need, therefore, at a minimum, to prevent any loss of the bedrock-aquifer resource--to maintain it in terms of both sustainable use and water-quality protection. The framework of the Newark basin bedrock aquifer included characterization of (1) the structure and fracture occurrence associated with the Newark basin strata, (2) the texture and thickness of overlying glacial and alluvial deposits, (3) the presence of the Palisades sill and associated basaltic units on or within the Newark basin strata, and (4) the streams that drain the aquifer system. The greatest concern regarding sustainability of groundwater resources is the aquifer response to the seasonal increase in pumping rates from May through October (an average increase

  19. Ice-dammed lake drainage in west Greenland: Drainage pattern and implications on ice flow and bedrock motion

    DEFF Research Database (Denmark)

    Kjeldsen, Kristian Kjellerup; Khan, Shfaqat Abbas; Bjørk, Anders

    2017-01-01

    of surface loading in addition to ice mass change, when assessing glacial isostatic adjustment or elastic rebound using geodetic data. Moreover, the results illustrates a linkage between subglacial discharge and ice surface velocity, important for assessing ice flux, and thus mass balance, in a future......Ice-dammed lakes drain frequently in Greenland, but the impacts of these events differ between sites. Here we study the quasi-cyclic behavior of the ~40 km2 Lake Tininnilik in west Greenland and its impact on ice flow and crustal deformation. Data reveal rapid drainage of 1.83 ± 0.17 km3 of water...... in less than 7 days in 2010, leading to a speedup of the damming glacier, and an instantaneous modeled elastic bedrock uplift of 18.6 ± 0.1 mm confirmed by an independent lakeside GPS record. Since ice-dammed lakes are common on Greenland, our results highlight the importance of including other sources...

  20. Mapping geological structures in bedrock via large-scale direct current resistivity and time-domain induced polarization tomography

    DEFF Research Database (Denmark)

    Rossi, Matteo; Olsson, Per-Ivar; Johansson, Sara

    2017-01-01

    An investigation of geological conditions is always a key point for planning infrastructure constructions. Bedrock surface and rock quality must be estimated carefully in the designing process of infrastructures. A large direct-current resistivity and time-domain induced-polarization survey has......, there are northwest-trending Permian dolerite dykes that are less deformed. Four 2D direct-current resistivity and time-domain induced-polarization profiles of about 1-km length have been carefully pre-processed to retrieve time-domain induced polarization responses and inverted to obtain the direct......-current resistivity distribution of the subsoil and the phase of the complex conductivity using a constant-phase angle model. The joint interpretation of electrical resistivity and induced-polarization models leads to a better understanding of complex three-dimensional subsoil geometries. The results have been...

  1. Ice-dammed lake drainage in west Greenland: Drainage pattern and implications on ice flow and bedrock motion

    Science.gov (United States)

    Kjeldsen, Kristian K.; Khan, Shfaqat A.; Bjørk, Anders A.; Nielsen, Karina; Mouginot, Jeremie

    2017-07-01

    Ice-dammed lakes drain frequently in Greenland, but the impacts of these events differ between sites. Here we study the quasi-cyclic behavior of the 40 km2 Lake Tininnilik in west Greenland and its impact on ice flow and crustal deformation. Data reveal rapid drainage of 1.83 ± 0.17 km3 of water in less than 7 days in 2010, leading to a speedup of the damming glacier, and an instantaneous modeled elastic bedrock uplift of 18.6 ± 0.1 mm confirmed by an independent lakeside GPS record. Since ice-dammed lakes are common on Greenland, our results highlight the importance of including other sources of surface loading in addition to ice mass change, when assessing glacial isostatic adjustment or elastic rebound using geodetic data. Moreover, the results illustrates a linkage between subglacial discharge and ice surface velocity, important for assessing ice flux, and thus mass balance, in a future warming climate.

  2. MATCHED-INDEX-OF-REFRACTION FLOW FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Carl Stoots; Donald M. McEligot; Richard Skifton; Hugh McIlroy

    2014-11-01

    Significant challenges face reactor designers with regard to thermal hydraulic design and associated modeling for advanced reactor concepts. Computational thermal hydraulic codes solve only a piece of the core. There is a need for a whole core dynamics system code with local resolution to investigate and understand flow behavior with all the relevant physics and thermo-mechanics. The matched index of refraction (MIR) flow facility at Idaho National Laboratory (INL) has a unique capability to contribute to the development of validated computational fluid dynamics (CFD) codes through the use of state-of-the-art optical measurement techniques, such as Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV). PIV is a non-intrusive velocity measurement technique that tracks flow by imaging the movement of small tracer particles within a fluid. At the heart of a PIV calculation is the cross correlation algorithm, which is used to estimate the displacement of particles in some small part of the image over the time span between two images. Generally, the displacement is indicated by the location of the largest peak. To quantify these measurements accurately, sophisticated processing algorithms correlate the locations of particles within the image to estimate the velocity (Ref. 1). Prior to use with reactor deign, the CFD codes have to be experimentally validated, which requires rigorous experimental measurements to produce high quality, multi-dimensional flow field data with error quantification methodologies. Computational thermal hydraulic codes solve only a piece of the core. There is a need for a whole core dynamics system code with local resolution to investigate and understand flow behavior with all the relevant physics and thermo-mechanics. Computational techniques with supporting test data may be needed to address the heat transfer from the fuel to the coolant during the transition from turbulent to laminar flow, including the possibility of an early laminarization of the flow (Refs. 2 and 3) (laminarization is caused when the coolant velocity is theoretically in the turbulent regime, but the heat transfer properties are indicative of the coolant velocity being in the laminar regime). Such studies are complicated enough that computational fluid dynamics (CFD) models may not converge to the same conclusion. Thus, experimentally scaled thermal hydraulic data with uncertainties should be developed to support modeling and simulation for verification and validation activities. The fluid/solid index of refraction matching technique allows optical access in and around geometries that would otherwise be impossible while the large test section of the INL system provides better spatial and temporal resolution than comparable facilities. Benchmark data for assessing computational fluid dynamics can be acquired for external flows, internal flows, and coupled internal/external flows for better understanding of physical phenomena of interest. The core objective of this study is to describe MIR and its capabilities, and mention current development areas for uncertainty quantification, mainly the uncertainty surface method and cross-correlation method. Using these methods, it is anticipated to establish a suitable approach to quantify PIV uncertainty for experiments performed in the MIR.

  3. Estimation of microbial metabolism and co-occurrence patterns in fracture groundwaters of deep crystalline bedrock at Olkiluoto, Finland

    Science.gov (United States)

    Bomberg, M.; Lamminmäki, T.; Itävaara, M.

    2015-08-01

    The microbial diversity in oligotrophic isolated crystalline Fennoscandian Shield bedrock fracture groundwaters is great but the core community has not been identified. Here we characterized the bacterial and archaeal communities in 12 water conductive fractures situated at depths between 296 and 798 m by high throughput amplicon sequencing using the Illumina HiSeq platform. The great sequencing depth revealed that up to 95 and 99 % of the bacterial and archaeal communities, respectively, were composed of only a few common species, i.e. the core microbiome. However, the remaining rare microbiome contained over 3 and 6 fold more bacterial and archaeal taxa. Several clusters of co-occurring rare taxa were identified, which correlated significantly with physicochemical parameters, such as salinity, concentration of inorganic or organic carbon, sulphur, pH and depth. The metabolic properties of the microbial communities were predicted using PICRUSt. The rough prediction showed that the metabolic pathways included commonly fermentation, fatty acid oxidation, glycolysis/gluconeogenesis, oxidative phosphorylation and methanogenesis/anaerobic methane oxidation, but carbon fixation through the Calvin cycle, reductive TCA cycle and the Wood-Ljungdahl pathway was also predicted. The rare microbiome is an unlimited source of genomic functionality in all ecosystems. It may consist of remnants of microbial communities prevailing in earlier conditions on Earth, but could also be induced again if changes in their living conditions occur. In this study only the rare taxa correlated with any physicochemical parameters. Thus these microorganisms can respond to environmental change caused by physical or biological factors that may lead to alterations in the diversity and function of the microbial communities in crystalline bedrock environments.

  4. Faulting and erosion in the Argentine Precordillera during changes in subduction regime: Reconciling bedrock cooling and detrital records

    Science.gov (United States)

    Fosdick, Julie C.; Carrapa, Barbara; Ortíz, Gustavo

    2015-12-01

    The Argentine Precordillera is an archetypal retroarc fold-and-thrust belt that records tectonics associated with changing subduction regimes. The interactions between exhumation and faulting in the Precordillera were investigated using apatite and zircon (U-Th-Sm)/He and apatite fission track thermochronometry from the Precordillera and adjacent geologic domains. Inverse modeling of thermal histories constrains eastward in-sequence rock cooling associated with deformation and erosion from 18 to 2 Ma across the Central Precordillera tracking thrusting during this time. The youngest AHe ages (5-2 Ma) and highest erosion rates are located in the eastern and western extremities of the Precordillera and indicate that recent denudation is concentrated at its structural boundaries. Moreover, synchronous rapid Pliocene cooling of the Frontal Cordillera, Eastern Precordillera, and Sierra del Valle Fértil was coeval with initiation of basement-involved faulting in the foreland. Detrital zircon U-Pb geochronology from the ca. 16-8.1 Ma Bermejo foreland basin strata suggests fluvial connectivity westward beyond the Frontal Cordillera to the Main Cordillera and Coast Range followed by an important shift in sediment provenance at ca. 10 Ma. At this time, we suggest that a substantial decrease in Permo-Triassic igneous sources in the Frontal Cordillera and concurrent increase in recycled zircons signatures of Paleozoic strata are best explained by uplift and erosion of the Precordillera during widening of the thrust-belt. Bedrock thermochronology and modeling indicate a 2-6 Myr lag time between faulting-related cooling in the hinterland and the detrital record of deformation in the foreland basin, suggesting that for tectonically active semi-arid settings, bedrock cooling may be more sensitive to onset of faulting. We suggest that high erosion rates in the Frontal Cordillera and Eastern Precordillera are associated with increased interplate coupling during shallowing of the

  5. Groundtruthing and potential for predicting acid deposition impacts in headwater streams using bedrock geology, GIS, angling, and stream chemistry.

    Science.gov (United States)

    Kirby, C S; McInerney, B; Turner, M D

    2008-04-15

    Atmospheric acid deposition is of environmental concern worldwide, and the determination of impacts in remote areas can be problematic. Rainwater in central Pennsylvania, USA, has a mean pH of approximately 4.4. Bedrock varies dramatically in its ability to neutralize acidity. A GIS database simplified reconnaissance of non-carbonate bedrock streams in the Valley and Ridge Province and identified potentially chronically impacted headwater streams, which were sampled for chemistry and brook trout. Stream sites (n=26) that originate in and flow through the Tuscarora had a median pH of 5.0 that was significantly different from other formations. Shawangunk streams (n=6) and non-Tuscarora streams (n=20) had a median pH of 6.0 and 6.3, respectively. Mean alkalinity for non-Tuscarora streams (2.6 mg/L CaCO(3)) was higher than the mean for Tuscarora streams (0.5 mg/L). Lower pH and alkalinity suggest that the buffering capability of the Tuscarora is inferior to that of adjacent sandstones. Dissolved aluminum concentrations were much higher for Tuscarora streams (0.2 mg/L; approximately the lethal limit for brook trout) than for non-Tuscarora streams (0.03 mg/L) or Shawangunk streams (0.02 mg/L). Hook-and-line methods determined the presence/absence of brook trout in 47 stream reaches with suitable habitat. Brook trout were observed in 21 of 22 non-Tuscarora streams, all 6 Shawangunk streams, and only 9 of 28 Tuscarora stream sites. Carefully-designed hook-and-line sampling can determine the presence or absence of brook trout and help confirm biological impacts of acid deposition. 15% of 334 km of Tuscarora stream lengths are listed as "impaired" due to atmospheric deposition by the Pennsylvania Department of Environmental Protection. 65% of the 101 km of Tuscarora stream lengths examined in this study were impaired.

  6. Modeling flow through the sand pack: implications for groundwater sampling from multi- level monitoring wells in fractured bedrock aquifers.

    Science.gov (United States)

    Kozuskanich, J.; Novakowski, K.; Anderson, B.

    2009-05-01

    Multi-level piezometers are often used in groundwater studies to monitor multiple zones within a single borehole. In the fractured rock setting the monitoring intervals are typically designed to isolate discrete fracture features (single fractures or fracture zones). This can be very useful for determining vertical connectivity and the distribution of a contaminant within a fractured rock aquifer. A simple and inexpensive method for completing a bedrock borehole as a multi-level piezometer is to use PVC screen and riser, a sand pack around the screened section, and bentonite to isolate each interval. Flow into the borehole is dominantly confined to the intersecting discrete fracture features. The objective of this study is to examine the nature of the flow through the sand pack and screen slots as water travels from the fracture to the pump intake under pumping conditions. Our conceptual model suggests only a portion of the sand pack in the vicinity of the fractures should be hydraulically active in this scenario. Thus, portions of the wellbore may remain stagnant during pumping depending on the location of the pump intake with respect to the fractures. Flow paths in the sand pack may be controlled by the relationship between the transmissivity of the fracture and screen slots. HydroGeoSphere, a numerical model for flow and solute transport in discrete fractures and porous media, will be used to validate the conceptual model and define the head and velocity profiles in a multi-level interval under various pumping rate and discrete fracture aperture scenarios. The results of this study could have implications for defining a "well volume" in sampling protocols designed for multi-level piezometers in bedrock aquifer systems. The results may also be a useful tool for interpreting the significance of the sand pack as a source of bacteria in water quality monitoring studies that use multi-level piezometer construction of this sort.

  7. Geologic and physiographic controls on bed-material yield, transport, and channel morphology for alluvial and bedrock rivers, western Oregon

    Science.gov (United States)

    O'Connor, James E.; Mangano, Joseph F.; Anderson, Scott A.; Wallick, J. Rose; Jones, Krista L.; Keith, Mackenzie K.

    2014-01-01

    The rivers of western Oregon have diverse forms and characteristics, with channel substrates ranging from continuous alluvial gravel to bare bedrock. Analysis of several measurable morphologic attributes of 24 valley reaches on 17 rivers provides a basis for comparing nonalluvial and alluvial channels. Key differences are that alluvial reaches have greater bar area, greater migration rates, and show systematic correlation among variables relating grain size to bed-material transport capacity. We relate these differences between channel types to bed-material transport rates as derived from a coupled regional analysis of empirical sediment yield measurements and physical experiments of clast attrition during transport. This sediment supply analysis shows that overall bed-material transport rates for western Oregon are chiefly controlled by (1) lithology and basin slope, which are the key factors for bed-material supply into the stream network, and (2) lithologic control of bed-material attrition from in-transport abrasion and disintegration. This bed-material comminution strongly affects bed-material transport in the study area, reducing transport rates by 50%–90% along the length of the larger rivers in the study area. A comparison of the bed-material transport estimates with the morphologic analyses shows that alluvial gravel-bed channels have systematic and bounding relations between bed-material transport rate and attributes such as bar area and local transport capacity. By contrast, few such relations are evident for nonalluvial rivers with bedrock or mixed-bed substrates, which are apparently more influenced by local controls on channel geometry and sediment supply. At the scale of western Oregon, the physiographic and lithologic controls on the balance between bed-material supply and transport capacity exert far-reaching influence on the distribution of alluvial and nonalluvial channels and their consequently distinctive morphologies and behaviors

  8. Groundwater in the Broken Hill region, Australia: recognising interaction with bedrock and mineralisation using S, Sr and Pb isotopes

    International Nuclear Information System (INIS)

    Caritat, Patrice de; Kirste, Dirk; Carr, Graham; McCulloch, Malcolm

    2005-01-01

    The supergiant Pb-Zn-Ag Broken Hill orebody and numerous other minor mineral deposits occur within the limited outcrop of the Proterozoic Curnamona Province of Australia. The vast majority of this Province is concealed by up to 200 m of transported regolith, hampering conventional exploration strategies. Approximately 300 groundwater samples were collected over the southern Curnamona Province to test whether this medium could be helpful in the search for hidden mineral deposits. Sulphur, Sr and Pb isotope composition of the groundwaters were determined and S excess (S XS ), i.e., the amount of S that can be ascribed neither to evaporation nor to mixing, was calculated. Many samples were recognised to have undergone an addition of 34 S-depleted S, which can be attributed to oxidation of sulfides with a Broken Hill type δ 34 S signature (average ∼0%o V-CDT). Furthermore, Sr isotopes identify the broad types of bedrock that the groundwater has been interacting with, from the less radiogenic Adelaidean rocks (and minerals) in the west (groundwater 87 Sr/ 86 Sr ratio as low as 0.708) to the highly radiogenic Willyama Supergroup in the east ( 87 Sr/ 86 Sr ratio up to 0.737). The groundwaters have 207 Pb/ 204 Pb and 206 Pb/ 204 Pb ratios comparable to, or intermediate between, various mineralisation types recognised in the area (Broken Hill, Rupee, Thackaringa, etc., types). The few samples taken in the vicinity of known mineralisation yield positive indicators (positive S XS , low δ 34 S, 87 Sr/ 86 Sr signature of bedrock type and Pb isotope fingerprinting of mineralisation type). This study also highlights several new locations under sedimentary cover where these indicators suggest interaction with mineralisation

  9. Estimation of the groundwater resources of the bedrock aquifers at the Kettle Moraine Springs State Fish Hatchery, Sheboygan County, Wisconsin

    Science.gov (United States)

    Dunning, Charles; Feinstein, Daniel T.; Buchwald, Cheryl A.; Hunt, Randall J.; Haserodt, Megan

    2017-10-12

    Groundwater resources information was needed to understand regional aquifer systems and water available to wells and springs for rearing important Lake Michigan fish species at the Kettle Moraine Springs State Fish Hatchery in Sheboygan County, Wisconsin. As a basis for estimating the groundwater resources available, an existing groundwater-flow model was refined, and new groundwater-flow models were developed for the Kettle Moraine Springs State Fish Hatchery area using the U.S. Geological Survey (USGS) finite-difference code MODFLOW. This report describes the origin and construction of these groundwater-flow models and their use in testing conceptual models and simulating the hydrogeologic system.The study area is in the Eastern Ridges and Lowlands geographical province of Wisconsin, and the hatchery property is situated on the southeastern edge of the Kettle Moraine, a north-south trending topographic high of glacial origin. The bedrock units underlying the study area consist of Cambrian, Ordovician, and Silurian units of carbonate and siliciclastic lithology. In the Sheboygan County area, the sedimentary bedrock sequence reaches a thickness of as much as about 1,600 feet (ft).Two aquifer systems are present at the Kettle Moraine Springs State Fish Hatchery. A shallow system is made up of Silurian bedrock, consisting chiefly of dolomite, overlain by unconsolidated Quaternary-age glacial deposits. The glacial deposits of this aquifer system are the typical source of water to local springs, including the springs that have historically supplied the hatchery. The shallow aquifer system, therefore, consists of the unconsolidated glacial aquifer and the underlying bedrock Silurian aquifer. Most residential wells in the area draw from the Silurian aquifer. A deeper confined aquifer system is made up of Cambrian- and Ordovician-age bedrock units including sandstone formations. Because of its depth, very few wells are completed in the Cambrian-Ordovician aquifer system

  10. Sediment Dynamics and the Burial and Exhumation of Bedrock Reefs as Elucidated by High-resolution Repetitive Sonar Surveys: Northern Monterey Bay, CA

    Science.gov (United States)

    Storlazzi, C. D.; Fregoso, T. A.; Golden, N. E.; Finlayson, D. P.

    2011-12-01

    Two high-resolution bathymetric and acoustic backscatter sonar surveys were conducted along the energetic emergent inner shelf of northern Monterey Bay, CA, USA, in the fall of 2005 and the spring of 2006 to determine the impact of winter storm waves, beach erosion, and river floods on biologically-important bedrock reef habitats. The surveys extended from water depths of 4 m to 22 m and covered an area of 3.14 km2, of which 45.8% was bedrock, gravel, and coarse-grained sand and 54.2% was fine-grained sand. Our analysis of the bathymetric and acoustic backscatter data demonstrates that during the 6 months between surveys, 11.4% of the study area was buried by fine-grained sand while erosion exposed of bedrock or coarse-grained sand over 26.5% of the study area. The probability of burial decreased with increasing water depth and rugosity; the probability of exhumation increased with increasing seabed slope and rugosity. Much of the detected change was at the boundary between bedrock and unconsolidated sediment due to burial or exhumation of bedrock. In a number of cases, however, the change in seabed character was apparently due to fluctuations in sediment grain size, where scour exposed what appeared to be an underlying coarser-grained lag or fine-grained sand buried coarser-grained sand. These findings suggest that, in some places, (a) single acoustic surveys typically employed for geologic characterization and/or habitat mapping may not adequately characterize the geomorphology and sedimentologic nature of rocky, energetic inner shelves, and (b) burial and exhumation likely play a role in the life history of the numerous organisms that inhabit these reefs and thus information on the frequency and magnitude of such processes may better constrain our understanding of physical controls on benthic species' distribution patterns.

  11. Bedrock geologic map of the Miles Pond and Concord quadrangles, Essex and Caledonia Counties, Vermont, and Grafton County, New Hampshire

    Science.gov (United States)

    Rankin, Douglas W.

    2018-04-20

    The bedrock geologic map of the Miles Pond and Concord quadrangles covers an area of approximately 107 square miles (276 square kilometers) in east-central Vermont and adjacent New Hampshire, north of and along the Connecticut River. This map was created as part of a larger effort to produce a new bedrock geologic map of Vermont through the collection of field data at a scale of 1:24,000. The majority of the map area consists of the Bronson Hill anticlinorium, a post-Early Devonian structure that is cored by metamorphosed Cambrian to Silurian sedimentary, volcanic, and plutonic rocks. A major feature on the map is the Monroe fault, interpreted to be a west-directed, steeply dipping Late Devonian (Acadian) thrust fault. To the west of the Monroe fault, rocks of the Connecticut Valley-Gaspé trough dominate and consist primarily of metamorphosed Silurian and Devonian sedimentary rocks. To the north, the Victory pluton intrudes the Bronson Hill anticlinorium. The Bronson Hill anticlinorium consists of the metamorphosed Albee Formation, the Ammonoosuc Volcanics, the Comerford Intrusive Complex, the Highlandcroft Granodiorite, and the Joselin Turn tonalite. The Albee Formation is an interlayered, feldspathic metasandstone and pelite that is locally sulfidic. Much of the deformed metasandstone is tectonically pinstriped. In places, one can see compositional layering that was transposed by a steeply southeast-dipping foliation. The Ammonoosuc Volcanics are lithologically complex and predominantly include interlayered and interfingered rhyolitic to basaltic volcanic and volcaniclastic rocks, as well as lesser amounts of siltstone, phyllite, graywacke, and grit. The Comerford Intrusive Complex crops out east of the Monroe fault and consists of metamorphosed gabbro, diorite, tonalite, aplitic tonalite, and crosscutting diabase dikes. Abundant mafic dikes from the Comerford Intrusive Complex intruded the Albee Formation and Ammonoosuc Volcanics east of the Monroe fault. The

  12. Bedrock Geologic Map of the Miles Pond and Concord Quadrangles, Essex and Caledonia Counties, Vermont, and Grafton County, New Hampshire

    Science.gov (United States)

    Rankin, Douglas W.

    2018-04-20

    The bedrock geologic map of the Miles Pond and Concord quadrangles covers an area of approximately 107 square miles (276 square kilometers) in east-central Vermont and adjacent New Hampshire, north of and along the Connecticut River. This map was created as part of a larger effort to produce a new bedrock geologic map of Vermont through the collection of field data at a scale of 1:24,000. The majority of the map area consists of the Bronson Hill anticlinorium, a post-Early Devonian structure that is cored by metamorphosed Cambrian to Silurian sedimentary, volcanic, and plutonic rocks. A major feature on the map is the Monroe fault, interpreted to be a west-directed, steeply dipping Late Devonian (Acadian) thrust fault. To the west of the Monroe fault, rocks of the Connecticut Valley-Gaspé trough dominate and consist primarily of metamorphosed Silurian and Devonian sedimentary rocks. To the north, the Victory pluton intrudes the Bronson Hill anticlinorium. The Bronson Hill anticlinorium consists of the metamorphosed Albee Formation, the Ammonoosuc Volcanics, the Comerford Intrusive Complex, the Highlandcroft Granodiorite, and the Joselin Turn tonalite. The Albee Formation is an interlayered, feldspathic metasandstone and pelite that is locally sulfidic. Much of the deformed metasandstone is tectonically pinstriped. In places, one can see compositional layering that was transposed by a steeply southeast-dipping foliation. The Ammonoosuc Volcanics are lithologically complex and predominantly include interlayered and interfingered rhyolitic to basaltic volcanic and volcaniclastic rocks, as well as lesser amounts of siltstone, phyllite, graywacke, and grit. The Comerford Intrusive Complex crops out east of the Monroe fault and consists of metamorphosed gabbro, diorite, tonalite, aplitic tonalite, and crosscutting diabase dikes. Abundant mafic dikes from the Comerford Intrusive Complex intruded the Albee Formation and Ammonoosuc Volcanics east of the Monroe fault. The

  13. Flow and sorption controls of groundwater arsenic in individual boreholes from bedrock aquifers in central Maine, USA.

    Science.gov (United States)

    Yang, Qiang; Culbertson, Charles W; Nielsen, Martha G; Schalk, Charles W; Johnson, Carole D; Marvinney, Robert G; Stute, Martin; Zheng, Yan

    2015-02-01

    To understand the hydrogeochemical processes regulating well water arsenic (As) evolution in fractured bedrock aquifers, three domestic wells with [As] up to 478 μg/L are investigated in central Maine. Geophysical logging reveals that fractures near the borehole bottom contribute 70-100% of flow. Borehole and fracture water samples from various depths show significant proportions of As (up to 69%) and Fe (93-99%) in particulates (>0.45 μm). These particulates and those settled after a 16-day batch experiment contain 560-13,000 mg/kg of As and 14-35% weight/weight of Fe. As/Fe ratios (2.5-20 mmol/mol) and As partitioning ratios (adsorbed/dissolved [As], 20,000-100,000 L/kg) suggest that As is sorbed onto amorphous hydrous ferric oxides. Newly drilled cores also show enrichment of As (up to 1300 mg/kg) sorbed onto secondary iron minerals on the fracture surfaces. Pumping at high flow rates induces large decreases in particulate As and Fe, a moderate increase in dissolved [As] and As(III)/As ratio, while little change in major ion chemistry. The δD and δ(18)O are similar for the borehole and fracture waters, suggesting a same source of recharge from atmospheric precipitation. Results support a conceptual model invoking flow and sorption controls on groundwater [As] in fractured bedrock aquifers whereby oxygen infiltration promotes the oxidation of As-bearing sulfides at shallower depths in the oxic portion of the flow path releasing As and Fe; followed by Fe oxidation to form Fe oxyhydroxide particulates, which are transported in fractures and sorb As along the flow path until intercepted by boreholes. In the anoxic portions of the flow path, reductive dissolution of As-sorbed iron particulates could re-mobilize As. For exposure assessment, we recommend sampling of groundwater without filtration to obtain total As concentration in groundwater. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Influence of hydrological and geochemical processes on the transport of chelated metals and chromate in fractured shale bedrock.

    Science.gov (United States)

    Jardine, P M; Mehlhorn, T L; Larsen, I L; Bailey, W B; Brooks, S C; Roh, Y; Gwo, J P

    2002-03-01

    Field-scale processes governing the transport of chelated radionuclides in groundwater remain conceptually unclear for highly structured, heterogeneous environments. The objectives of this research were to provide an improved understanding and predictive capability of the hydrological and geochemical mechanisms that control the transport behavior of chelated radionuclides and metals in anoxic subsurface environments that are complicated by fracture flow and matrix diffusion. Our approach involved a long-term, steady-state natural gradient field experiment where nonreactive Br- and reactive 57Co(II)EDTA2- 109CdEDTA2-, and 51Cr(VI) were injected into a fracture zone of a contaminated fractured shale bedrock. The spatial and temporal distribution of the tracer and solutes was monitored for 500 days using an array of groundwater sampling wells instrumented within the fast-flowing fracture regime and a slower flowing matrix regime. The tracers were preferentially transported along strike-parallel fractures coupled with the slow diffusion of significant tracer mass into the bedrock matrix. The chelated radionuclides and metals were significantly retarded by the solid phase with the mechanisms of retardation largely due to redox reactions and sorption coupled with mineral-induced chelate-radionuclide dissociation. The formation of significant Fe(III)EDTA byproduct that accompanied the dissociation of the radionuclide-chelate complexes was believed to be the result of surface interactions with biotite which was the only Fe(III)-bearing mineral phase present in these Fe-reducing environments. These results counter current conceptual models that suggest chelated contaminants move conservatively through Fe-reducing environments since they are devoid of Fe-oxyhydroxides that are known to aggressively compete for chelates in oxic regimes. Modeling results further demonstrated that chelate-radionuclide dissociation reactions were most prevalent along fractures where accelerated

  15. Sediment dynamics and the burial and exhumation of bedrock reefs along an emergent coastline as elucidated by repetitive sonar surveys: Northern Monterey Bay, CA

    Science.gov (United States)

    Storlazzi, C.D.; Fregoso, T.A.; Golden, N.E.; Finlayson, D.P.

    2011-01-01

    Two high-resolution bathymetric and acoustic backscatter sonar surveys were conducted along the energetic emergent inner shelf of northern Monterey Bay, CA, USA, in the fall of 2005 and the spring of 2006 to determine the impact of winter storm waves, beach erosion, and river floods on biologically-important siliclastic bedrock reef habitats. The surveys extended from water depths of 4 m to 22 m and covered an area of 3.14 km2, 45.8% of which was bedrock, gravel, and coarse-grained sand and 54.2% was fine-grained sand. Our analyses of the bathymetric and acoustic backscatter data demonstrates that during the 6 months between surveys, 11.4% of the study area was buried by fine-grained sand while erosion resulted in the exposure of bedrock or coarse-grained sand over 26.5% of the study area. The probability of burial decreased with increasing water depth and rugosity; the probability of exhumation increased with increasing wave-induced near-bed shear stress, seabed slope and rugosity. Much of the detected change was at the boundary between bedrock and unconsolidated sediment due to sedimentation and erosion burying or exhuming bedrock, respectively. In a number of cases, however, the change in seabed character was apparently due to changes in sediment grain size when scour exposed what appeared to be an underlying coarser-grained lag or the burial of coarser-grained sand and gravel by fine-grained sand. These findings suggest that, in some places, (a) burial and exhumation of nearshore bedrock reefs along rocky, energetic inner shelves occurs over seasonal timescales and appears related to intrinsic factors such as seabed morphology and extrinsic factors such as wave forces, and (b) single acoustic surveys typically employed for geologic characterization and/or habitat mapping may not adequately characterize the geomorphologic and sedimentologic nature of these types of environments that typify most of the Pacific Ocean and up to 50% of the world's coastlines.

  16. Hydrochemical investigations in crystalline bedrock in relation to existing hydraulic conditions: experiences from the SKB test-sites in Sweden

    International Nuclear Information System (INIS)

    Smellie, J.; Larsson, N.Aa.; Wikberg, P.; Carlsson, L.

    1985-11-01

    This report represents the compilation, discussion and interpretation of hydrochemical and hydraulic data resulting from the SKB test-site investigations carried out over a period of three years (1982-84). By systematically applying hydrological and geological considerations to each sampled horizon, it has been possible to differentiate between those groundwaters which are reasonably representative for the depth sampled, from those which have been subject to contamination from different sources. Groundwaters which are here considered representative are defined as those which show no evidence of mixing with other water sources, whether from drilling water, younger, near-surface water, or other deeper groundwaters. As a consequence, only a few sampled horizons can be considered with serious hydrochemical attention. The lack of representative groundwater samples, whilst often due to technical problems or sampling from non-conductive sections of the boreholes, also illustrate the extremely complex geometry of the premeable fracture systems in crystalline bedrock, and thus the difficulty of establishing the nature and depth relation of the groundwater tapped. Although the main findings of this study have revealed gross inadequacies in the hydrochemical programme, valuable experience has nevertheless been gained. Consequently, some of the improvements recommended in Section 7 of this report have been already implemented resulting in higher sampling standards and thus water samples which are much more representative for the hydrogeological environment under investigation. (author)

  17. Hydrochemistry of surface water and groundwater in the shale bedrock, Cross River Basin and Niger Delta Region, Nigeria

    Science.gov (United States)

    Nganje, T. N.; Hursthouse, A. S.; Edet, Aniekan; Stirling, D.; Adamu, C. I.

    2017-05-01

    Water chemistry in the shale bedrock of the Cretaceous-Tertiary of the Cross River and Niger Delta hydrological basins has been investigated using major ions. To carry out a characterization of the water bearing units, 30 and 16 representatives surface and groundwater samples were collected. The evolution of the water is characterized by enhanced content of sodium, calcium and sulphate as a result of leaching of shale rock. The spatial changes in groundwater quality of the area shows an anomalous concentrations of ions in the central parts, while lower values characterize the eastern part of the basin covering Ogoja, Ikom and Odukpani areas. The values of total dissolved solids (TDS) and ions increases down gradient in the direction of groundwater flow. The dissolution of halite and gypsum explains part of the contained Na+, Ca2+, Cl- and SO4 2-, but other processes such as ion exchange, silicate weathering and pyrite oxidation also contribute to water composition. The assessment with contamination indicators such as TDS, hardness, chloride, nitrate and sulphate indicates that the water in area is suitable for human consumption in some locations. Modelling using MINTEQA2 program shows that the water from all the shale water bearing units are under saturated with respect to gypsum.

  18. Digital representation of exposures of Precambrian bedrock in parts of Dickinson and Iron Counties, Michigan, and Florence and Marinette Counties, Wisconsin

    Science.gov (United States)

    Cannon, William F.; Schulte, Ruth; Bickerstaff, Damon

    2018-04-04

    The U.S. Geological Survey (USGS) conducted a program of bedrock geologic mapping in much of the central and western Upper Peninsula of Michigan from the 1940s until the late 1990s. Geologic studies in this region are hampered by a scarcity of bedrock exposures because of a nearly continuous blanket of unconsolidated sediments resulting from glaciation of the region during the Pleistocene ice ages. The USGS mapping, done largely at a scale of 1:24,000, routinely recorded the location and extent of exposed bedrock to provide both an indication of where direct observations were made and a guide for future investigations to expedite location of observable rock exposures. The locations of outcrops were generally shown as colored or patterned overlays on printed geologic maps. Although those maps have been scanned and are available as Portable Document Format (PDF) files, no further digital portrayal of the outcrops had been done. We have conducted a prototype study of digitizing and improving locational accuracy of the outcrop locations in parts of Dickinson County, Michigan, to form a data layer that can be used with other data layers in geographic information system applications.

  19. The use of capacitive resistivity imaging (CRI) for monitoring laboratory experiments simulating permafrost growth, persistence and thaw in bedrock

    Science.gov (United States)

    Kuras, O.; Uhlemann, S.; Krautblatter, M.; Murton, J.; Haslam, E.; Wilkinson, P.; Meldrum, P.

    2012-12-01

    Understanding the impact on bedrock properties of permafrost degradation as a result of climate change is of major interest in a number of areas, including the assessment of rising instability of high-altitude mountain rock walls. The remote sensing of rock walls with the primary aim of monitoring the spatial and temporal behaviour of rock temperature (and thus permafrost distribution) is an emerging field of research for geohazard mitigation where geophysical tomography has the potential to make a significant and lasting contribution. Recent work has shown that temperature-calibrated Electrical Resistivity Tomography (ERT) using galvanic sensors is capable of imaging recession and re-advance of rock permafrost in response to the ambient temperature regime, yet the use of galvanic sensors can impose practical limitations on field measurements. In this study, we evaluate the use of Capacitive Resistivity Imaging (CRI), a technique based upon low-frequency, capacitively-coupled measurements across permanently installed multi-sensor arrays, in order to emulate well-established ERT methodology, but without the need for galvanic contact on frozen soils or rocks. Numerical simulation of multi-sensor CRI measurements on the rock samples under a quasi-static electromagnetic regime allowed us initially to validate our measurement concept and prototype CRI instrumentation. We have subsequently applied CRI as well as conventional ERT to controlled long-term experiments in the Permafrost Laboratory at the University of Sussex, simulating permafrost growth, persistence and thaw in bedrock. Water-saturated samples of limestone and chalk (450 mm high, 300 mm × 300 mm wide) of varying porosity are being monitored. The lower half of each sample is maintained at temperatures below 0°C (simulating permafrost) and the upper half is cycled above and below 0°C (simulating seasonal thawing and freezing of the overlying active layer). Samples are instrumented with both capacitive and

  20. Sedimentary infilling of bedrock-controlled palaeo-embayments off Cape Trafalgar, Strait of Gibraltar (Gulf of Cadiz)

    Science.gov (United States)

    de Castro, Sandra; Lobo, Francisco J.

    2018-02-01

    This study investigates two bedrock-controlled palaeo-coastal embayments on the Barbate Platform off Cape Trafalgar near the Strait of Gibraltar (Gulf of Cadiz shelf, SW Iberian Peninsula), aiming to reveal their infilling dynamics and the influence of rocky outcrops on shallow-water hydrodynamics and sediment transport. The approach relies on detailed multibeam bathymetric data, high-resolution seismic profiles and tidal current simulations. Elongated rocky outcrops formed a palaeo-coast when sea level was approximately 35 to 20 m below that of the present day, and bound a relatively flat area. However, the seismic profiles enabled to distinguish two main troughs (A and B) that were infilled following a distinctive evolution during the last transgression. Five seismic units were identified (I to V, from base to top). Deposit A is composed of seismic units II to V and is interpreted as a marine embayment infill, here termed the Barbate palaeo-embayment (BPE). Deposit B is composed of seismic units I to IV and is interpreted as a palaeo-valley infill, here termed the Barbate palaeo-valley (BPV). The complex internal stratigraphic architecture depicts an overall evolution from tidal/fluvial deposits to shallow-water marine deposits. Most significant is the occurrence of coupled tidal flats/estuarine sand bars constituting the infilling of the BPE; this suggests the persistence of a high-energy current in a shallow, confined embayment, which was amplified by the rocky outcrop constrictions and possibly facilitated by the episodic movement of a normal fault. In contrast to this active setting, the nearby straight and narrow BPV was subjected to lower-energy infilling dynamics during its initial flooding phases. There, tidal activity was possibly reduced by the straight morphology of the valley and the occurrence of a topographic constriction (i.e. the Barbate Passage) at the mouth of the valley.

  1. Hydraulic responses to extreme drought conditions in three co-dominant tree species in shallow soil over bedrock.

    Science.gov (United States)

    Kukowski, Kelly R; Schwinning, Susanne; Schwartz, Benjamin F

    2013-04-01

    An important component of the hydrological niche involves the partitioning of water sources, but in landscapes characterized by shallow soils over fractured bedrock, root growth is highly constrained. We conducted a study to determine how physical constraints in the root zone affected the water use of three tree species that commonly coexist on the Edwards Plateau of central Texas; cedar elm (Ulmus crassifolia), live oak (Quercus fusiformis), and Ashe juniper (Juniperus ashei). The year of the study was unusually dry; minimum predawn water potentials measured in August were -8 MPa in juniper, less than -8 MPa in elm, and -5 MPa in oak. All year long, species used nearly identical water sources, based on stable isotope analysis of stem water. Sap flow velocities began to decline simultaneously in May, but the rate of decline was fastest for oak and slowest for juniper. Thus, species partitioned water by time when they could not partition water by source. Juniper lost 15-30 % of its stem hydraulic conductivity, while percent loss for oak was 70-75 %, and 90 % for elm. There was no tree mortality in the year of the study, but 2 years later, after an even more severe drought in 2011, we recorded 34, 14, 6, and 1 % mortality among oak, elm, juniper, and Texas persimmon (Diospyros texana), respectively. Among the study species, mortality rates ranked in the same order as the rate of sap flow decline in 2009. Among the angiosperms, mortality rates correlated with wood density, lending further support to the hypothesis that species with more cavitation-resistant xylem are more susceptible to catastrophic hydraulic failure under acute drought.

  2. Bedrock geology and mineral resources of the Knoxville 1° x 2° quadrangle, Tennessee, North Carolina, and South Carolina

    Science.gov (United States)

    Robinson,, Gilpin R.; Lesure, Frank G.; Marlowe, J. I.; Foley, Nora K.; Clark, S.H.

    2004-01-01

    The Knoxville 1°x 2° quadrangle spans the Southern Blue Ridge physiographic province at its widest point from eastern Tennessee across western North Carolina to the northwest corner of South Carolina. The quadrangle also contains small parts of the Valley and Ridge province in Tennessee and the Piedmont province in North and South Carolina. Bedrock in the Valley and Ridge consists of unmetamorphosed, folded and thrust-faulted Paleozoic miogeoclinal sedimentary rocks ranging in age from Cambrian to Mississippian. The Blue Ridge is a complex of stacked thrust sheets divided into three parts: (1) a west flank underlain by rocks of the Late Proterozoic and Early Cambrian Chilhowee Group and slightly metamorphosed Late Proterozoic Ocoee Supergroup west of the Greenbrier fault; (2) a central part containing crystalline basement of Middle Proterozoic age (Grenville), Ocoee Supergroup rocks east of the Greenbrier fault, and rocks of the Murphy belt; and (3) an east flank containing the Helen, Tallulah Falls, and Richard Russell thrust sheets and the amphibolitic basement complex. All of the east flank thrust sheets contain polydeformed and metamorphosed sedimentary and igneous rocks of mostly Proterozoic age. The Blue Ridge is separated by the Brevard fault zone from a large area of rocks of the Inner Piedmont to the east, which contains the Six Mile thrust sheet and the ChaugaWalhalla thrust complex. All of these rocks are also polydeformed and metamorphosed sedimentary and igneous rocks. The Inner Piedmont rocks in this area occupy both the Piedmont and part of the Blue Ridge physiographic provinces.

  3. Variations of Lateral Bedrock Erosion Rates Control Planation of Uplifting Folds in the Foreland of the Tian Shan, NW China

    Science.gov (United States)

    Bufe, Aaron; Burbank, Douglas W.; Liu, Langtao; Bookhagen, Bodo; Qin, Jintang; Chen, Jie; Li, Tao; Thompson Jobe, Jessica A.; Yang, Huili

    2017-12-01

    Fluvial planation surfaces, such as straths, commonly serve as recorders of climatic and tectonic changes and are formed by the lateral erosion of rivers, a process that remains poorly understood. Here we present a study of kilometer-wide, fluvially eroded, low-relief surfaces on rapidly uplifting folds in the foreland of the southwestern Tian Shan. A combination of field work, digital elevation model analysis, and dating of fluvial deposits reveals that despite an arid climate and rapid average rock-uplift rates of 1-3 mm/yr, rivers cut extensive (>1-2 km wide) surfaces with typical height variations of 2-6 kyr. The extent of this "beveling" varies in space and time, such that different beveling episodes affect individual structures. Between times of planation, beveled surfaces are abandoned, incised, and deformed across the folds. In a challenge to models that link strath cutting and abandonment primarily to changes in river incision rates, we demonstrate that lateral erosion rates of antecedent streams crossing the folds have to vary by more than 1 order of magnitude to explain the creation of beveled platforms in the past and their incision at the present day. These variations do not appear to covary with climate variability and might be caused by relatively small (much less than an order of magnitude) changes in sediment or water fluxes. It remains uncertain in which settings variations in lateral bedrock erosion rates predominate over changes in vertical erosion rates. Therefore, when studying fluvial planation and strath terraces, variability of both lateral and vertical erosion rates should be considered.

  4. Fluvial response time during continuous climate change: A new formulation and applications to climatically and tectonically modulated bedrock fluvial channels

    Science.gov (United States)

    Goren, L.; Petit, C.

    2016-12-01

    Fluvial channels respond to changing tectonic and climatic conditions by adjusting their patterns of erosion and relief. It is therefore expected that by examining these patterns, we can infer the tectonic and climatic conditions that shaped the channels. However, the potential interference between climatic and tectonic signals complicates this inference. Within the framework of the stream power model that describes incision rates of mountainous bedrock rivers, climate variability has two effects: first, it influences the erosive power of the river, causing local slope change, and second, it changes the fluvial response time, that controls the rate at which tectonic and climatic variations are communicated upstream. Because of this dual role, the definition of the response time during continuous climate change has so far been elusive, which hindered our understanding of environmental signal propagation and preservation in the fluvial topography. Here, we propose a new definition of fluvial response time that is based on an analytic solution of the stream power model during any general tectonic and climatic histories. This response time depends on space, time, and climatic history, and it allows using river long profiles to recover either the tectonic history or the climatic history. Furthermore, analytic study of landscape evolution during periodic climate change reveals that high frequency climatic oscillations (with respect to the response time), such as Milankovitch cycles, are topographically damped. The new response time definition is applied to the analysis of the Tinee river tributaries in the southern French Alps. Tributaries long profile is used to recover the incision history of the Tinee main trunk, which shows periodic, high incision rate pulses correlated with interglacial episodes. Similar incision histories are recovered for the past 100 ky when assuming constant climatic conditions or periodic climatic oscillations following global temperature curve.

  5. Identification of Bedrock Lithology using Fractal Dimensions of Drainage Networks extracted from Medium Resolution LiDAR Digital Terrain Models

    Science.gov (United States)

    Cámara, Joaquín; Gómez-Miguel, Vicente; Martín, Miguel Ángel

    2016-03-01

    Geologists know that drainage networks can exhibit different drainage patterns depending on the hydrogeological properties of the underlying materials. Geographic Information System (GIS) technologies and the increasing availability and resolution of digital elevation data have greatly facilitated the delineation, quantification, and study of drainage networks. This study investigates the possibility of inferring geological information of the underlying material from fractal and linear parameters describing drainage networks automatically extracted from 5-m-resolution LiDAR digital terrain model (DTM) data. According to the lithological information (scale 1:25,000), the study area is comprised of 30 homogeneous bedrock lithologies, the lithological map units (LMUs). These are mostly igneous and metamorphic rocks, but also include some sedimentary rocks. A statistical classification model of the LMUs by rock type has been proposed based on both the fractal dimension and drainage density of the overlying drainage networks. The classification model has been built using 16 LMUs, and it has correctly classified 13 of the 14 LMUs used for its validation. Results for the study area show that LMUs, with areas ranging from 177.83 ± 0.01 to 3.16 ± 0.01 km2, can be successfully classified by rock type using the fractal dimension and the drainage density of the drainage networks derived from medium resolution LiDAR DTM data with different flow support areas. These results imply that the information included in a 5-m-resolution LiDAR DTM and the appropriate techniques employed to manage it are the only inputs required to identify the underlying geological materials.

  6. Reactive transport modeling of dissolved organic matter and iron in the Bengal Basin and Mahomet Bedrock Valley aquifers

    Science.gov (United States)

    Mladenov, N.; Kulkarni, H. V.; Steward, D. R.; Datta, S.

    2016-12-01

    Despite their different geography, geology and hydrology, Bengal Basin (BB) and Mahomet Bedrock Valley (MBV) aquifers have some key processes in common that mobilize arsenic (As) into groundwater. Groundwater flow, transport of sedimentary labile carbon and dissolved organic matter (DOM) through a multi-layer aquifer system, and microbial interactions together play an important role in the discontinuous As distribution. This study characterized and compared the DOM in high and low As groundwaters in BB and MBV aquifers and developed refined hydrogeological flow models for each of the aquifers. Fluorescence indices suggested substantially more humified and decomposed DOM character in high As (>50 ppb) zones than in low As (<50 ppb) zones in both aquifers. Modeling results indicate North-West to South-East flow with velocity of 7.2 cm/day for the BB aquifer and South-East to North-West with velocity of 35 cm/day for the MBV aquifer. A transport model including advection, dispersion, sorption and reaction was developed to understand the distribution of dissolved iron (Fe) in domains. A modified Monod rate law was used to simulate acetotrophic Fe reduction influenced by the presence of humic-like DOM, based on experimental data. The model produced a Fe2+ distribution, which was similar to that observed in high and low As sites in the BB aquifer. Meanwhile, in the MBV aquifer model, the dispersion of Fe2+ was found to be lower due to higher hydraulic gradient. Model results further indicated that in 30 years these processes would mobilize Fe2+ up to 1.4 km and 5 km in BB and MBV aquifers, respectively. While the quality of DOM in the two aquifers showed similarities, diverse flow and transport conditions may result in more localized and widespread distributions of Fe2+ and As in the BB and MBV aquifers respectively.

  7. Delineation of Groundwater Flow Pathway in Fractured Bedrock Using Nano-Iron Tracer Test in the Sealed Well

    Science.gov (United States)

    Chuang, Po-Yu; Chia, Yeeping; Chiu, Yung-Chia; Liou, Ya-Hsuan; Teng, Mao-Hua; Liu, Ching-Yi; Lee, Tsai-Ping

    2016-04-01

    Deterministic delineation of the preferential flow paths and their hydraulic properties are desirable for developing hydrogeological conceptual models in bedrock aquifers. In this study, we proposed using nanoscale zero-valent iron (nZVI) as a tracer to characterize the fractured connectivity and hydraulic properties. Since nZVI particles are magnetic, we designed a magnet array to attract the arriving nZVI particles in the observation well for identifying the location of incoming tracer. This novel approach was examined at two experiment wells with well hydraulic connectivity in a hydrogeological research station in the fractured aquifer. Heat-pulse flowmeter test was used to detect the vertical distribution of permeable zones in the borehole, providing the design basis of tracer test. Then, the less permeable zones in the injection well were sealed by casing to prevent the injected nZVI particles from being stagnated at the bottom hole. Afterwards, hydraulic test was implemented to examine the hydraulic connectivity between two wells. When nZVI slurry was released in the injection well, they could migrate through connected permeable fractures to the observation well. A breakthrough curve was obtained by the fluid conductivity sensor in the observation well, indicating the arrival of nZVI slurry. The iron nanoparticles that were attracted to the magnets in the observation well provide the quantitative information to locate the position of tracer inlet, which corroborates well with the depth of a permeable zone delineated by the flowmeter. Finally, the numerical method was utilized to simulate the process of tracer migration. This article demonstrates that nano-iron tracer test can be a promising approach for characterizing connectivity patterns and transmissivities of the flow paths in the fractured rock.

  8. Estimates of groundwater age from till and carbonate bedrock hydrogeologic units at Jefferson Proving Ground, Southeastern Indiana, 2007-08

    Science.gov (United States)

    Buszka, Paul M.; Lampe, David C.; Egler, Amanda L.

    2010-01-01

    During 2007-08, the U.S. Geological Survey, in cooperation with the U.S. Department of the Army, conducted a study to evaluate the relative age of groundwater in Pre-Wisconsinan till and underlying shallow and deep carbonate bedrock units in and near an area at Jefferson Proving Ground (JPG), southeastern Indiana, which was used during 1984-94 to test fire depleted uranium (DU) penetrators. The shallow carbonate unit includes about the upper 40 feet of bedrock below the bedrock-till surface; the deeper carbonate unit includes wells completed at greater depth. Samples collected during April 2008 from 15 wells were analyzed for field water-quality parameters, dissolved gases, tritium, and chlorofluorocarbon (CFC) compounds; samples from 14 additional wells were analyzed for tritium only. Water-level gradients in the Pre-Wisconsinan till and the shallow carbonate unit were from topographically higher areas toward Big Creek and Middle Fork Creek, and their tributaries. Vertical gradients were strongly downward from the shallow carbonate unit toward the deep carbonate unit at 3 of 4 paired wells where water levels recovered after development; indicating the general lack of flow between the two units. The lack of post development recovery of water levels at 4 other wells in the deep carbonate unit indicate that parts of that unit have no appreciable permeability. CFC and tritium-based age dates of Pre-Wisconsinan till groundwater are consistent with infiltration of younger (typically post-1960 age) recharge that 'mixes' with older recharge from less permeable or less interconnected strata. Part of the recharge to three till wells dated from the early to mid-1980s (JPG-DU-03O, JPG-DU-09O, and JPG-DU-10O). Age dates of young recharge in water from two till wells predated 1980 (JPG-DU-04O and JPG-DU-06O). Tritium-based age dates of water from seven other till wells indicated post-1972 age recharge. Most wells in the Pre-Wisconsinan till have the potential to produce

  9. Lithologic and hydrologic controls of mixed alluvial-bedrock channels in flood-prone fluvial systems: bankfull and macrochannels in the Llano River watershed, central Texas, USA

    Science.gov (United States)

    Heitmuller, Frank T.; Hudson, Paul F.; Asquith, William H.

    2015-01-01

    The rural and unregulated Llano River watershed located in central Texas, USA, has a highly variable flow regime and a wide range of instantaneous peak flows. Abrupt transitions in surface lithology exist along the main-stem channel course. Both of these characteristics afford an opportunity to examine hydrologic, lithologic, and sedimentary controls on downstream changes in channel morphology. Field surveys of channel topography and boundary composition are coupled with sediment analyses, hydraulic computations, flood-frequency analyses, and geographic information system mapping to discern controls on channel geometry (profile, pattern, and shape) and dimensions along the mixed alluvial-bedrock Llano River and key tributaries. Four categories of channel classification in a downstream direction include: (i) uppermost ephemeral reaches, (ii) straight or sinuous gravel-bed channels in Cretaceous carbonate sedimentary zones, (iii) straight or sinuous gravel-bed or bedrock channels in Paleozoic sedimentary zones, and (iv) straight, braided, or multithread mixed alluvial–bedrock channels with sandy beds in Precambrian igneous and metamorphic zones. Principal findings include: (i) a nearly linear channel profile attributed to resistant bedrock incision checkpoints; (ii) statistically significant correlations of both alluvial sinuosity and valley confinement to relatively high f (mean depth) hydraulic geometry values; (iii) relatively high b (width) hydraulic geometry values in partly confined settings with sinuous channels upstream from a prominent incision checkpoint; (iv) different functional flow categories including frequently occurring events (high f values (most ≤ 0.45) that develop at sites with unit stream power values in excess of 200 watts per square meter (W/m2); and (vi) downstream convergence of hydraulic geometry exponents for bankfull and macrochannels, explained by co-increases of flood magnitude and noncohesive sandy sediments that collectively

  10. Geology, Bedrock, Tabular data involving the location of design specifics for wells related to the Low-level Radioactive Waste (LLRW) Site Characterization., Published in 1998, North Carolina Department of Environment and Natural Resources (DENR).

    Data.gov (United States)

    NSGIC State | GIS Inventory — Geology, Bedrock dataset current as of 1998. Tabular data involving the location of design specifics for wells related to the Low-level Radioactive Waste (LLRW) Site...

  11. Building deals on bedrock.

    Science.gov (United States)

    Harding, David; Rovit, Sam

    2004-09-01

    The headlines are filled with the sorry tales of companies like Vivendi and AOL Time Warner that tried to use mergers and acquisitions to grow big fast or transform fundamentally weak business models. But, drawing on extensive data and experience, the authors conclude that major deals make sense in only two circumstances: when they reinforce a company's existing basis of competition or when they help a company make the shift, as the industry's competitive base changes. In most stable industries, the authors contend, only one basis--superior cost position, brand power, consumer loyalty, real-asset advantage, or government protection--leads to industry leadership, and companies should do only those deals that bolster a strategy to capitalize on that competitive base. That's what Kellogg did when it acquired Keebler. Rather than bow to price pressures from lesser players, Kellogg sought to strengthen its existing basis of competition--its brand--through Keebler's innovative distribution system. A company coping with a changing industry should embark on a series of acquisitions (most likely coupled with divestitures) aimed at moving the firm to the new competitive basis. That's what Comcast did when changes in government regulations fundamentally altered the broadcast industry. In such cases, speed is essential, the investments required are huge, and half-measures can be worse than nothing at all. Still, the research shows, successful acquirers are not those that try to swallow a single, large, supposedly transformative deal but those that go to the M&A table often and take small bites. Deals can fuel growth--as long as they're anchored in the fundamental way money is made in your industry. Fail to understand that and no amount of integration planning will keep you and your shareholders from bearing the high cost of your mistakes.

  12. Iowa Bedrock Faults

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This fault coverage locates and identifies all currently known/interpreted fault zones in Iowa, that demonstrate offset of geologic units in exposure or subsurface...

  13. Geology and bedrock engineering

    International Nuclear Information System (INIS)

    1985-11-01

    This book deals with geology of Korea which includes summary, geology in central part and southern part in Korea and characteristic of geology structure, limestone like geology property of limestone, engineered property of limestone, and design and construction case in limestone area. It also introduces engineered property of the cenozoic, clay rock and shale, geologic and engineered property of phyllite and stratum.

  14. Infiltration into Fractured Bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Salve, Rohit; Ghezzehei, Teamrat A.; Jones, Robert

    2007-09-01

    One potential consequence of global climate change and rapid changes in land use is an increased risk of flooding. Proper understanding of floodwater infiltration thus becomes a crucial component of our preparedness to meet the environmental challenges of projected climate change. In this paper, we present the results of a long-term infiltration experiment performed on fractured ash flow tuff. Water was released from a 3 x 4 m{sup 2} infiltration plot (divided into 12 square subplots) with a head of {approx}0.04 m, over a period of {approx}800 days. This experiment revealed peculiar infiltration patterns not amenable to current infiltration models, which were originally developed for infiltration into soils over a short duration. In particular, we observed that in part of the infiltration plot, the infiltration rate abruptly increased a few weeks into the infiltration tests. We suggest that these anomalies result from increases in fracture permeability during infiltration, which may be caused by swelling of clay fillings and/or erosion of infill debris. Interaction of the infiltration water with subsurface natural cavities (lithophysal cavities) could also contribute to such anomalies. This paper provides a conceptual model that partly describes the observed infiltration patterns in fractured rock and highlights some of the pitfalls associated with direct extension of soil infiltration models to fractured rock over a long period.

  15. Acceptance-criteria for the bedrock for deep geologic disposal of spent nuclear fuel. Proceedings from a seminar at Gothenburg University; Acceptanskriterier foer berggrunden vid djup geologisk slutfoervaring av anvaent kaernbraensle

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    The seminar was directed to Nordic participants, and discussed disposal in the Nordic crystalline bedrock. Criteria for the bedrock should include: It should give durable mechanical protection for the engineered barriers; give a stable and favorable chemical environment for these barriers; have a low turnover of ground water in the near field; be easy to characterize; give favorable recipient-conditions; not have valuable minerals in workable quantities. These general criteria raise several questions coupled to the safety analysis: e.g. the need for geological, hydrological and geochemical parameters. Which data are missing, which are most difficult to find? What should the site characterization program look like to focus on factors that are of the highest importance according to the safety analysis. The demands on the conditions at a site need to be translated into quantitative criteria, which should be expressed as values that can be measured at the site or deduced from such measurements. These questions were discussed at the seminar, and 21 contributions from Finnish, Norwegian and Swedish participants are reported in these proceedings under the chapters: Coupling to the safety analysis; Methodology and criteria for site selection in a regional geoscientific perspective; Rock as a building material - prognosis and result; Geoscientific criteria for the bedrock at the repository - Mechanical protection; Geoscientific criteria for the bedrock at the repository - Low ground water turnover, chemically favorable and stable environment in the near field; Geoscientific criteria for the bedrock at the repository - Demands on the bedrock concerning the migration of radionuclides.

  16. Linking carbon and hydrologic fluxes in the critical zone: Observations from high-frequency monitoring of a weathered bedrock vadose zone

    Science.gov (United States)

    Tune, A. K.; Druhan, J. L.; Wang, J.; Cargill, S.; Murphy, C.; Rempe, D. M.

    2017-12-01

    A principle challenge in quantifying feedbacks between continental weathering and atmospheric CO2 is to improve understanding of how biogeochemical processes in the critical zone influence the distribution and mobility of organic and inorganic carbon. In particular, in landscapes characterized by thin soils and heterogeneous weathered and fractured bedrock, little data exist to inform and constrain predictive models for carbon dynamics. Here, we present the results of an intensive water and gas sampling campaign across an 18 m thick, variably saturated argillite weathering profile in the Eel River CZO. We monitor water content in situ and regularly collect samples of freely-draining water, tightly-held water, and gas through wet and dry seasons using a novel Vadose-zone Monitoring System (VMS) consisting of sensors and samplers distributed across a 20 m long inclined borehole. This novel approach facilitates the interception of gas and water during transport across the entire variably saturated weathering profile. The data demonstrate that seasonal changes in saturation control the vertical distribution and mobility of carbon in the fractured critical zone. Concentrations of gaseous CO2, O2, and dissolved organic and inorganic carbon fluctuate significantly and repeatably with seasonal additions of water infiltrating the weathered bedrock. A persistent vertical structure in the concentrations of dissolved phases and gas concentrations broadly corresponds to depths associated with unsaturated, seasonally saturated, and chronically saturated zones. Associated variations in the vertical structure of mineralogy and elemental composition, including solid phase organic carbon content, are observed in core obtained during drilling. Together, our observations indicate significant respiration of organic carbon at depths greater than the base of the soil, and thus motivate further investigation of the role of heterogeneous weathered, bedrock environments, which are needed to

  17. Tidal control on gas flux from the Precambrian continental bedrock revealed by gas monitoring at the Outokumpu Deep Drill Hole, Finland

    Science.gov (United States)

    Kietäväinen, Riikka; Ahonen, Lasse; Wiersberg, Thomas; Korhonen, Kimmo; Pullinen, Arto

    2017-04-01

    Deep groundwaters within Precambrian shields are characteristically enriched in non-atmospheric gases. High concentrations of methane are frequently observed especially in graphite bearing metasedimentary rocks and accumulation of hydrogen and noble gases due to water-rock interaction and radioactive decay within the U, Th and K containing bedrock takes place. These gases can migrate not only through fractures and faults, but also through tunnels and boreholes, thereby potentially mobilizing hazardous compounds for example from underground nuclear waste repositories. Better understanding on fluid migration may also provide tools to monitor changes in bedrock properties such as fracture density or deterioration and failure of engineered barriers. In order to study gas migration mechanisms and variations with time, we conducted a gas monitoring campaign in eastern Finland within the Precambrian Fennoscandian Shield. At the study site, the Outokumpu Deep Drill Hole (2516 m), spontaneous bubbling of gases at the well head has been on-going since the drilling was completed in 2005, i.e. over a decade. The drill hole is open below 39 m. In the experiment an inflatable packer was placed 15 cm above the water table inside the collar (Ø 32.4 cm), gas from below the packer was collected and the gas flow in the pipe line carefully assisted by pumping (130 ml/min). Composition of gas was monitored on-line for one month using a quadrupole mass spectrometer (QMS) with measurement interval of one minute. Changes in the hydraulic head and in situ temperature were simultaneously recorded with two pressure sensors which were placed 1 m apart from each other below the packer such that they remained above and below the water table. In addition, data was compared with atmospheric pressure data and theoretical effect of Earth tides at the study site. Methane was the dominant gas emanating from the bedrock, however, relative gas composition fluctuated with time. Subsurface derived gases

  18. Disposal of spent fuel in Olkiluoto bedrock. Programme for research, development and technical design for the pre-construction phase

    International Nuclear Information System (INIS)

    2000-12-01

    The spent fuel from the nuclear power plants at Olkiluoto and Loviisa will be disposed of in Finnish bedrock. Posiva aims at starting the construction of the disposal facility in the 2010's and the actual disposal operations in 2020. In May 1999 Posiva submitted an application for the so-called Decision-in-Principle (DiP) on the facility to the Finnish Government. According to the application the repository would be based on a KBS-3 type concept and sited at Olkiluoto. The application was approved by the Government in December 2000 and will go next to the Parliament for final approval. However, Posiva has already started the planning for the next programme phase on the assumption that a positive decision will be made. The purpose of the present document is to describe the objectives and major items of research, development, technical planning and design work for the period preceding the construction license. According to the current official guidelines Posiva should prepare for submitting the application for the license in 2010. For the technical development and design work the main target for the starting programme phase is to reach the maturity of design and technical plans that allows the specification of work packages for bid calls and gives sufficient confidence in the technical feasibility of planned operations at the encapsulation facility and in the repository. The main objectives for the complementary characterisation work at Olkiluoto consist of the verification of the present conclusions on site suitability, the definition and identification of suitable rock volumes for repository space and the characterisation of the target host rock for repository design, safety assessment and planning of construction work. The technical design and demonstration work together with the results of complementary site characterisation will provide the basis of the safety case prepared as the support for the construction license application. An integrated safety assessment

  19. Potential impacts of human water management on the European heat wave 2003 using fully integrated bedrock-to-atmosphere simulations

    Science.gov (United States)

    Keune, Jessica; Sulis, Mauro; Kollet, Stefan; Wada, Yoshihide

    2017-04-01

    Recent studies indicate that anthropogenic impacts on the terrestrial water cycle lead to a redistribution of water resources in space and time, can trigger land-atmosphere feedbacks, such as the soil moisture-precipitation feedback, and potentially enhance convection and precipitation. Yet, these studies do not consider the full hydrologic cycle from the bedrock to the atmosphere or apply simplified hydrologic models, neglecting the connection of irrigation to water withdrawal and groundwater depletion. Thus, there is a need to incorporate water resource management in 3D hydrologic models coupled to earth system models. This study addresses the impact of water resource management, i.e. irrigation and groundwater abstraction, on land-atmosphere feedbacks through the terrestrial hydrologic cycle in a physics-based soil-vegetation-atmosphere system simulating 3D groundwater dynamics at the continental scale. The integrated Terrestrial Systems Modeling Platform, TerrSysMP, consisting of the three-dimensional subsurface and overland flow model ParFlow, the Community Land Model CLM3.5 and the numerical weather prediction model COSMO of the German Weather Service, is set up over the European CORDEX domain in 0.11° resolution. The model closes the terrestrial water and energy cycles from aquifers into the atmosphere. Anthropogenic impacts are considered by applying actual daily estimates of irrigation and groundwater abstraction from Wada et al. (2012, 2016), as a source at the land surface and explicit removal of groundwater from aquifer storage, respectively. Simulations of the fully coupled system are performed over the 2003 European heat wave and compared to a reference simulation, which does not consider human interactions in the terrestrial water cycle. We study the space and time characteristics and evolution of temperature extremes, and soil moisture and precipitation anomalies influenced by human water management during the heat wave. A first set of simulations

  20. Microbiology of transitional groundwater of the porous overburden and underlying fractured bedrock aquifers in Olkiluoto 2004, Finland

    International Nuclear Information System (INIS)

    Pedersen, K.

    2006-07-01

    The subsurface biosphere on Earth appears to be far more expansive and metabolically and phylogenetically complex than previously thought. A diverse suite of subsurface environments have been reported to support microbial ecosystems, extending from a few meters below the surface to several hundred meters. The discovery of a deep biosphere will have several important effects on underground repositories for radioactive wastes. The main potential effects of microorganisms in the context of a KBS-3 type repository for spent fuel in the bedrock of Olkiluoto are: Oxygen reduction and maintenance of anoxic and reduced conditions; Bio-immobilisation and bio-mobilisation of radionuclides, and the effects from microbial metabolism on radionuclide mobility; Sulphate reduction to sulphide and the potential for copper sulphide corrosion. The first main objective of this study was to characterize the geochemistry, biomass and microbial diversity of shallow subsurface groundwater at Olkiluoto, from 4.0 m down to 24.5 m. This objective also permitted the determination of whether or not there is any transition in the shallow depths at Olkiluoto to microbial conditions associated with the deep subsurface. The second main objective was to continue the study of biomass and microbial metabolic diversity in deep groundwater of Olkiluoto to a maximal depth of 525 m, using cultivation methods similar to those applied to the shallow groundwater. This was the first investigation that covered both shallow and deep groundwater microbiology. The analysis of microbiology is very important for proper understanding of the evolution of geochemical processes in and around the underground research facility ONKALO being constructed at Olkiluoto by Posiva since autumn 2004, as well as for the planned KBS-3 type spent fuel repository at Olkiluoto. There are several conclusions and hypotheses with respect to the microbiology that are of great importance for ONKALO and for the spent fuel repository. The

  1. Disposal of spent fuel in Olkiluoto bedrock. Programme for research, development and technical design for the pre-construction phase

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-12-01

    The spent fuel from the nuclear power plants at Olkiluoto and Loviisa will be disposed of in Finnish bedrock. Posiva aims at starting the construction of the disposal facility in the 2010's and the actual disposal operations in 2020. In May 1999 Posiva submitted an application for the so-called Decision-in-Principle (DiP) on the facility to the Finnish Government. According to the application the repository would be based on a KBS-3 type concept and sited at Olkiluoto. The application was approved by the Government in December 2000 and will go next to the Parliament for final approval. However, Posiva has already started the planning for the next programme phase on the assumption that a positive decision will be made. The purpose of the present document is to describe the objectives and major items of research, development, technical planning and design work for the period preceding the construction license. According to the current official guidelines Posiva should prepare for submitting the application for the license in 2010. For the technical development and design work the main target for the starting programme phase is to reach the maturity of design and technical plans that allows the specification of work packages for bid calls and gives sufficient confidence in the technical feasibility of planned operations at the encapsulation facility and in the repository. The main objectives for the complementary characterisation work at Olkiluoto consist of the verification of the present conclusions on site suitability, the definition and identification of suitable rock volumes for repository space and the characterisation of the target host rock for repository design, safety assessment and planning of construction work. The technical design and demonstration work together with the results of complementary site characterisation will provide the basis of the safety case prepared as the support for the construction license application. An integrated safety

  2. Analysis of workability of rocks and type of prequarternary bedrock in the selected part of the Ostrava conurbation by means of geographic information systems

    Directory of Open Access Journals (Sweden)

    Marian Marschalko

    2008-06-01

    Full Text Available An up-to-date topic with which engineering geology can contribute to the requirements of practice and research, in particularthe needs of land use planning, state administration, building offices, developers, etc. is an analysis of new possibilities of providingreference information on the engineering-geological conditions by means of geographic information systems. The study in the presentedpaper deals with an evaluation of two geofactors. They are the character of rocks workability and Pre-quaternary bedrock. Workabilityis a significant limiting factor, which affects the used technology and financial demands of earth work. Especially in case of demandingconstructions, the Pre-quaternary bedrock is a geological environment which will have to be interacted with and must be taken intoaccount during selecting engineering foundation. The overall project was divided into five model areas (1-5, while this paper evaluatesa partial model area of no.1, which is defined by topographical map in drawing scale 1:10 1000 (topographic sheet No. 15-43-10.Namely they are Slezské, Moravské Ostravy, Vítkovic a Radvanice. The mentioned methodology was applied in the interest area forthe first time.

  3. Numerical simulation of ground-water flow through glacial deposits and crystalline bedrock in the Mirror Lake area, Grafton County, New Hampshire

    Science.gov (United States)

    Tiedeman, Claire; Goode, Daniel J.; Hsieh, Paul A.

    1997-01-01

    This report documents the development of a computer model to simulate steady-state (long-term average) flow of ground water in the vicinity of Mirror Lake, which lies at the eastern end of the Hubbard Brook valley in central New Hampshire. The 10-km2 study area includes Mirror Lake, the three streams that flow into Mirror Lake, Leeman's Brook, Paradise Brook, and parts of Hubbard Brook and the Pemigewasset River. The topography of the area is characterized by steep hillsides and relatively flat valleys. Major hydrogeologic units include glacial deposits, composed of till containing pockets of sand and gravel, and fractured crystalline bedrock, composed of schist intruded by granite, pegmatite, and lamprophyre. Ground water occurs in both the glacial deposits and bedrock. Precipitation and snowmelt infiltrate to the water table on the hillsides, flow downslope through the saturated glacial deposits and fractured bedrock, and discharge to streams and to Mirror Lake. The model domain includes the glacial deposits, the uppermost 150m of bedrock, Mirror Lake, the layer of organic sediments on the lake bottom, and streams and rivers within the study area. A streamflow routing package was included in the model to simulate baseflow in streams and interaction between streams and ground water. Recharge from precipitation is assumed to be areally uniform, and riparian evapotranspiration along stream banks is assumed negligible. The spatial distribution of hydraulic conductivity is represented by dividing the model domain into several zones, each having uniform hydraulic properties. Local variations in recharge and hydraulic conductivities are ignored; therefore, the simulation results characterize the general ground-water system, not local details of ground-water movement. The model was calibrated using a nonlinear regression method to match hydraulic heads measured in piezometers and wells, and baseflow in three inlet streams to Mirror Lake. Model calibration indicates that

  4. Final disposal of spent fuel in the Finnish bedrock. Detailed site investigations 1993-1996; Kaeytetyn polttoaineen loppusijoitus Suomen kallioperaeaen. Yksityiskohtaiset sijoituspaikkatutkimukset 1993-1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    Posiva Oy, jointly owned company of Imatran Voima Oy (IVO) and Teollisuuden Voima Oy (TVO), studies the Finnish bedrock for the final disposal of the spent nuclear fuel. The study is in accordance with the decision in principle by Finnish government in 1983 and aims at site selection. The report is the summary of the first stage of the detailed site investigations carried out during the years 1993-1996. The three sites in question, Romuvaara in Kuhmo, Kivetty in Aeaenekoski and Olkiluoto in Eurajoki were selected for the detailed characterization on the basis of the preliminary site investigations at five areas. The interim reporting in 1996 is comprehensive and comprises a series of reports covering different disciplines and sites. The programme for 1993-1996 was divided into three sub-programs: (1) the baseline investigations describing the present conditions in the bedrock, (2) the additional characterization for the acquisition of complementary data, and (3) the investigations for testing the earlier results and hypotheses to build confidence in existing understanding. (refs.).

  5. Direct Measurements of Bedrock Incision Rates on the Surface of a Large Dip-slope Landslide by Multi-Period Airborne Laser Scanning DEMs

    Directory of Open Access Journals (Sweden)

    Yu-Chung Hsieh

    2016-10-01

    Full Text Available This study uses three periods of airborne laser scanning (ALS digital elevation model (DEM data to analyze the short-term erosional features of the Tsaoling landslide triggered by the 1999 Chi-Chi earthquake in Taiwan. Two methods for calculating the bedrock incision rate, the equal-interval cross section selection method and the continuous swath profiles selection method, were used in the study after nearly ten years of gully incision following the earthquake-triggered dip-slope landslide. Multi-temporal gully incision rates were obtained using the continuous swath profiles selection method, which is considered a practical and convenient approach in terrain change studies. After error estimation and comparison of the multi-period ALS DEMs, the terrain change in different periods can be directly calculated, reducing time-consuming fieldwork such as installation of erosion pins and measurement of topographic cross sections on site. The gully bedrock incision rate calculated by the three periods of ALS DEMs on the surface of the Tsaoling landslide ranged from 0.23 m/year to 3.98 m/year. The local gully incision rate in the lower part of the landslide surface was found to be remarkably faster than that of the other regions, suggesting that the fast incision of the toe area possibly contributes to the occurrence of repeated landslides in the Tsaoling area.

  6. Bedrock geologic map of the Lisbon quadrangle, and parts of the Sugar Hill and East Haverhill quadrangles, Grafton County, New Hampshire

    Science.gov (United States)

    Rankin, Douglas W.

    2018-04-20

    The bedrock geologic map of the Lisbon quadrangle, and parts of the Sugar Hill and East Haverhill quadrangles, Grafton County, New Hampshire, covers an area of approximately 73 square miles (189 square kilometers) in west-central New Hampshire. This map was created as part of a larger effort to produce a new bedrock geologic map of Vermont through the collection of field data at a scale of 1:24,000. A large part of the map area consists of the Bronson Hill anticlinorium, a post-Early Devonian structure that is cored by metamorphosed Cambrian to Devonian sedimentary, volcanic, and plutonic rocks.The Bronson Hill anticlinorium is the apex of the Middle Ordovician to earliest-Silurian Bronson Hill magmatic arc that contains the Ammonoosuc Volcanics, Partridge Formation, and Oliverian Plutonic Suite, and extends from Maine, through western New Hampshire (down the eastern side of the Connecticut River), through southern New England to Long Island Sound. The deformed and partially eroded arc is locally overlain by a relatively thin Silurian section of metasedimentary rocks (Clough Quartzite and Fitch Formation) that thickens to the east. The Silurian section near Littleton is disconformably overlain by a thicker, Lower Devonian section that includes mostly metasedimentary and minor metavolcanic rocks of the Littleton Formation. The Bronson Hill anticlinorium is bisected by a series of northeast-southwest trending Mesozoic normal faults. Primarily among them is the steeply northwest-dipping Ammonoosuc fault that divides older and younger units (lower and upper sections) of the Ammonoosuc Volcanics. The Ammonoosuc Volcanics are lithologically complex and predominantly include interlayered and interfingered rhyolitic to basaltic volcanic and volcaniclastic rocks, as well as lesser amounts of slate, phyllite, ironstone, chert, sandstone, and pelite. The Albee Formation underlies the Ammonoosuc Volcanics and is predominantly composed of interbedded metamorphosed sandstone

  7. Relations among water levels, specific conductance, and depths of bedrock fractures in four road-salt-contaminated wells in Maine, 2007–9

    Science.gov (United States)

    Schalk, Charles W.; Stasulis, Nicholas W.

    2012-01-01

    Data on groundwater-level, specific conductance (a surrogate for chloride), and temperature were collected continuously from 2007 through 2009 at four bedrock wells known to be affected by road salts in an effort to determine the effects of road salting and fractures in bedrock that intersect the well at a depth below the casing on the presence of chloride in groundwater. Dissolved-oxygen data collected periodically also were used to make inferences about the interaction of fractures and groundwater flow. Borehole geophysical tools were used to determine the depths of fractures in each well that were actively contributing flow to the well, under both static and pumped conditions; sample- and measurement-depths were selected to correspond to the depths of these active fractures. Samples of water from the wells, collected at depths corresponding to active bedrock fractures, were analyzed for chloride concentration and specific conductance; from these analyses, a linear relation between chloride concentration and specific conductance was established, and continuous and periodic measurements of specific conductance were assumed to represent chloride concentration of the well water at the depth of measurement. To varying degrees, specific conductance increased in at least two of the wells during winter and spring thaws; the shallowest well, which also was closest to the road receiving salt treatment during the winter, exhibited the largest changes in specific conductance during thaws. Recharge events during summer months, long after application of road salt had ceased for the year, also produced increases in specific conductance in some of the wells, indicating that chloride which had accumulated or sequestered in the overburden was transported to the wells throughout the year. Geophysical data and periodic profiles of water quality along the length of each well’s borehole indicated that the greatest changes in water quality were associated with active fractures; in

  8. Long-term controls on continental-scale bedrock river terrace deposition from integrated clast and heavy mineral assemblage analysis: An example from the lower Orange River, Namibia

    Science.gov (United States)

    Nakashole, Albertina N.; Hodgson, David M.; Chapman, Robert J.; Morgan, Dan J.; Jacob, Roger J.

    2018-02-01

    Establishing relationships between the long-term landscape evolution of drainage basins and the fill of sedimentary basins benefits from analysis of bedrock river terrace deposits. These fragmented detrital archives help to constrain changes in river system character and provenance during sediment transfer from continents (source) to oceans (sink). Thick diamondiferous gravel terrace deposits along the lower Orange River, southern Namibia, provide a rare opportunity to investigate controls on the incision history of a continental-scale bedrock river. Clast assemblage and heavy mineral data from seven localities permit detailed characterisation of the lower Orange River gravel terrace deposits. Two distinct fining-upward gravel terrace deposits are recognised, primarily based on mapped stratigraphic relationships (cross-cutting relationships) and strath and terrace top elevations, and secondarily on the proportion of exotic clasts, referred to as Proto Orange River deposits and Meso Orange River deposits. The older early to middle Miocene Proto Orange River gravels are thick (up to 50 m) and characterised by a dominance of Karoo Supergroup shale and sandstone clasts, whereas the younger Plio-Pleistocene Meso Orange River gravels (6-23 m thick) are characterised by more banded iron formation clasts. Mapping of the downstepping terraces indicates that the Proto gravels were deposited by a higher sinuosity river, and are strongly discordant to the modern Orange River course, whereas the Meso deposits were deposited by a lower sinuosity river. The heavy minerals present in both units comprise magnetite, garnet, amphibole, epidote and ilmenite, with rare titanite and zircon grains. The concentration of amphibole-epidote in the heavy minerals fraction increases from the Proto to the Meso deposits. The decrease in incision depths, recorded by deposit thicknesses above strath terraces, and the differences in clast character (size and roundness) and type between the two

  9. Comparing horizontal-to-vertical spectral ratios with sediment-to-bedrock spectral ratios in a region with a thin layer of unconsolidated sediments

    Science.gov (United States)

    Schleicher, L.; Pratt, T. L.

    2017-12-01

    Underlying sediment can amplify ground motions during earthquakes, making site response estimates key components in seismic evaluations for building infrastructure. The horizontal-to-vertical spectral ratio (HVSR) method, using either earthquake signals or ambient noise as input, is an appealing method for estimating site response because it uses only a single seismic station rather than requiring two or more seismometers traditionally used to compute a horizontal sediment-to-bedrock spectral ratio (SBSR). A number of studies have had mixed results when comparing the accuracy of the HVSR versus SBSR methods for identifying the frequencies and amplitudes of the primary resonance peaks. Many of these studies have been carried out in areas of complex geology, such as basins with structures that can introduce 3D effects. Here we assess the effectiveness of the HVSR method by a comparison with the SBSR method and models of transfer functions in an area dominated by a flat and thin, unconsolidated sediment layer over bedrock, which should be an ideal setting for using the HVSR method. In this preliminary study, we analyze teleseismic and regional earthquake recordings from a temporary seismometer array deployed throughout Washington, DC, which is underlain by a wedge of 0 to 270 m thick layer of unconsolidated Atlantic Coastal Plain sedimentary strata. At most sites, we find a close match in the amplitudes and frequencies of large resonance peaks in horizontal ground motions at frequencies of 0.7 to 5 Hz in site response estimates using the HVSR and SBSR methods. Amplitudes of the HVSRs tend to be slightly lower than SBSRs at 3 Hz and less, but the amplitudes of the fundamental resonance peaks often match closely. The results suggest that the HVSR method could be a successful approach to consider for computing site response estimates in areas of simple shallow geology consisting of thin sedimentary layers with a strong reflector at the underlying bedrock surface. [This

  10. Bedrock Geologic Map of the Lisbon Quadrangle, and Parts of the Sugar Hill and East Haverhill Quadrangles, Grafton County, New Hampshire

    Science.gov (United States)

    Rankin, Douglas W.

    2018-04-20

    The bedrock geologic map of the Lisbon quadrangle, and parts of the Sugar Hill and East Haverhill quadrangles, Grafton County, New Hampshire, covers an area of approximately73 square miles (189 square kilometers) in west-central New Hampshire. This map was created as part of a larger effort to produce a new bedrock geologic map of Vermont through the collection of field data at a scale of 1:24,000. A large part of the map area consists of the Bronson Hill anticlinorium, a post-Early Devonian structure that is cored by metamorphosed Cambrian to Devonian sedimentary, volcanic, and plutonic rocks.The Bronson Hill anticlinorium is the apex of the Middle Ordovician to earliest-Silurian Bronson Hill magmatic arc that contains the Ammonoosuc Volcanics, Partridge Formation, and Oliverian Plutonic Suite, and extends from Maine, through western New Hampshire (down the eastern side of the Connecticut River), through southern New England to Long Island Sound. The deformed and partially eroded arc is locally overlain by a relatively thin Silurian section of metasedimentary rocks (Clough Quartzite and Fitch Formation) that thickens to the east. The Silurian section near Littleton is disconformably overlain by a thicker, Lower Devonian section that includes mostly metasedimentary and minor metavolcanic rocks of the Littleton Formation. The Bronson Hill anticlinorium is bisected by a series of northeast-southwest trending Mesozoic normal faults. Primarily among them is the steeply northwest-dipping Ammonoosuc fault that divides older and younger units (lower and upper sections) of the Ammonoosuc Volcanics. The Ammonoosuc Volcanics are lithologically complex and predominantly include interlayered and interfingered rhyolitic to basaltic volcanic and volcaniclastic rocks, as well as lesser amounts of slate, phyllite, ironstone, chert, sandstone, and pelite. The Albee Formation underlies the Ammonoosuc Volcanics and is predominantly composed of interbedded metamorphosed sandstone

  11. Accuracy of CFC groundwater dating in a crystalline bedrock aquifer: Data from a site in southern Sweden

    Science.gov (United States)

    Bockgård, Niclas; Rodhe, Allan; Olsson, K. A.

    The concentrations of chlorofluorocarbons (CFC-11, CFC-12, and CFC-113) and tritium were determined in groundwater in fractured crystalline bedrock at Finnsjön, Sweden. The specific goal was to investigate the accuracy of CFC dating in such an environment, taking potential degradation and mixing of water into consideration. The water was sampled to a depth of 42 m in three boreholes along an 800-m transect, from a recharge area to a local discharge area. The CFC-113 concentration was at the detection limit in most samples. The apparent recharge date obtained from CFC-11 was earlier than from CFC-12 for all samples, with a difference of over 20 years for some samples. The difference was probably caused by degradation of CFC-11. The CFC-12 dating of the samples ranged from before 1945 to 1975, with the exception of a sample from the water table, which had a present-day concentration. Conclusions about flow paths or groundwater velocity could not be drawn from the CFCs. The comparison between CFC-12 and tritium concentrations showed that most samples could be unmixed or mixtures of waters with different ages, and the binary mixtures that matched the measured concentrations were determined. The mixing model approach can be extended with additional tracers. Précision de la datation au CFC dans un aquifère rocheux-fracturé: données d'un site du sud de la Suède. Les concentrations en chlorofluorocarbones (CFC-11, CFC-12, CFC-113) et entritium ont été déterminées dans l'eau souterraine d'un massif fracturé à Finnsjön en Suède. Le but de cette étude est de mieux cerner la précision de la méthode de datation au CFC dans ce type d'environnement hydrogéologique, tout en considérant d'éventuels phénomènes de dégradation et de mélange d'eaux. L'eau a été échantillonnée à une profondeur de 42 mètres dans trois forages alignés sur 800 mètres entre une zone de recharge et une zone de déversement. Les concentrations en CFC-113 sont dans la plupart

  12. Results of the reactant sand-fracking pilot test and implications for the in situ remediation of chlorinated VOCs and metals in deep and fractured bedrock aquifers.

    Science.gov (United States)

    Marcus, D L; Bonds, C

    1999-08-12

    Permeable reactive barriers (PRBs), such as the Waterloo Funnel and Gate System, first implemented at Canadian Forces Borden facility in 1992, are a passive remediation technology capable of controlling the migration of, and treating contaminated groundwater in situ. Most of the PRBs installed to date have been shallow installations created by backfilling sheet-pile shored excavations with iron filing reactive media. More recently continuous trenchers [R. Puls, Installation of permeable reactive barriers using continuous trenching equipment, Proceedings of the RTDF Permeable Barriers Work Group, Virginia Beach, VA, September 1997] and Caissons [J. Vogan, Caisson installation of a pilot scale, permeable reactive barrier in situ treatment zone at the Sommersworth Landfill, NH, Presented to the RTDF Permeable Barriers Work Group, Alexandria, VA, April 1996], and vertical fracturing emplacements [G. Hocking, Vertical hydraulic fracture emplacement of permeable reactive barriers, Progress Report delivered to the Permeable Reactive Barriers Workgroup of the Remedial Technology Development Forum, Beaverton, OR, April 1998] have been used to create reactive barriers in soil. None of the prior methods are capable of adequately addressing groundwater contamination in deep and fractured bedrock aquifers. The purpose of the RSF pilot study was to install reactive media into an impacted bedrock aquifer, and to evaluate the effectiveness of in situ treatment of chlorinated volatile organic compounds (CVOCs) and metals in that type of aquifer. Three discrete fractures were identified and treated and were subjected to testing before and after treatment. Between 300 and 1700 lb. of 1 mm diameter reactive proppants were injected into each zone to facilitate treatment. Monitoring data obtained from adjacent observation wells verified that fracking fluids reached at least 42 ft from the treatment well following hydrofracturing. The concentrations of many of the CVOCs decreased up to

  13. Gully incision rates on the bedrock of a large dip-slope landslide revealed by multi-period LiDAR DEMs

    Science.gov (United States)

    Chan, Y. C.; Hsieh, Y. C.

    2017-12-01

    Recent advances in airborne laser scanning (ALS) technology have provided a great opportunity for characterizing surface erosion through developing improved methods in multi-period DEM differencing and geomorphometry. This study uses three periods of ALS digital elevation model (DEM) data to analyze the short-term erosional features of the Tsaoling landslide triggered by the 1999 Chi-Chi earthquake in Taiwan. Two methods for calculating the bedrock incision rate, the equal-interval cross section selection method and the continuous swath profiles selection method, were used in the study after nearly ten years of gully incision following the earthquake-triggered dip-slope landslide. Multi-temporal gully incision rates were obtained using the continuous swath profiles selection method, which is considered a practical and convenient approach in terrain change studies. After error estimation and comparison of the multi-period ALS DEMs, the terrain change in different periods can be directly calculated, reducing time-consuming fieldwork such as installation of erosion pins and measurement of topographic cross sections on site. In this study, the gully bedrock incision rates ranged between 0.23 and 3.98 m/year, remarkably higher than the typical results from the previous studies. By comparing the DEM data, aerial photos, and precipitation records of this area, the effects of erosion could be observed from the retreat of the Chunqiu Cliff outline during August 2011 to September 2012. It was inferred that the change in the topographic elevation during 2011-2012 was mainly due to the torrential rain brought by Typhoon Soula, which occurred on 30 July 2012. The local gully incision rate in the lower part of the landslide surface was remarkably faster than that of the other regions, suggesting that the fast incision of the toe area possibly contributes to the occurrence of repeated landslides in the Tsaoling area.

  14. Final deposition of high-level nuclear waste in very deep boreholes. An evaluation based on recent research of bedrock conditions at great depths

    International Nuclear Information System (INIS)

    Aahaell, Karl-Inge

    2007-01-01

    This report evaluates the feasibility of very deep borehole disposal of high-level nuclear waste, e.g., spent nuclear fuel, in the light of recent technological developments and research on the characteristics of bedrock at extreme depths. The evaluation finds that new knowledge in the field of hydrogeology and technical advances in drilling technology have advanced the possibility of using very deep boreholes (3-5 km) for disposal of the Swedish nuclear waste. Decisive factors are (1) that the repository can be located in stable bedrock at a level where the groundwater is isolated from the biosphere, and (2) that the waste can be deposited and the boreholes permanently sealed without causing long-term disturbances in the density-stratification of the groundwater that surrounds the repository. Very deep borehole disposal might offer important advantage compared to the relatively more shallow KBS approach that is presently planned to be used by the Swedish nuclear industry in Sweden, in that it has the potential of being more robust. The reason for this is that very deep borehole disposal appears to permit emplacement of the waste at depths where the entire repository zone would be surrounded by stable, density-stratified groundwater having no contact with the surface, whereas a KBS-3 repository would be surrounded by upwardly mobile groundwater. This hydro-geological difference is a major safety factor, which is particularly apparent in all scenarios that envisage leakage of radioactive substances. Another advantage of a repository at a depth of 3 to 5 km is that it is less vulnerable to impacts from expected events (e.g., changes in groundwater conditions during future ice ages) as well as undesired events (e.g. such as terrorist actions, technical malfunction and major local earthquakes). Decisive for the feasibility of a repository based on the very deep borehole concept is, however, the ability to emplace the waste without failures. In order to achieve this

  15. Modeling Coupled Physical and Chemical Erosional Processes Using Structure from Motion Reconstruction and Multiphysics Simulation: Applications to Knickpoints in Bedrock Streams in Limestone Caves and on Earth's Surface

    Science.gov (United States)

    Bosch, R.; Ward, D.

    2017-12-01

    Investigation of erosion rates and processes at knickpoints in surface bedrock streams is an active area of research, involving complex feedbacks in the coupled relationships between dissolution, abrasion, and plucking that have not been sufficiently addressed. Even less research has addressed how these processes operate to propagate knickpoints through cave passages in layered sedimentary rocks, despite these features being common along subsurface streams. In both settings, there is evidence for mechanical and chemical erosion, but in cave passages the different hydrologic and hydraulic regimes, combined with an important role for the dissolution process, affect the relative roles and coupled interactions between these processes, and distinguish them from surface stream knickpoints. Using a novel approach of imaging cave passages using Structure from Motion (SFM), we create 3D geometry meshes to explore these systems using multiphysics simulation, and compare the processes as they occur in caves with those in surface streams. Here we focus on four field sites with actively eroding streambeds that include knickpoints: Upper River Acheron and Devil's Cooling Tub in Mammoth Cave, Kentucky; and two surface streams in Clermont County, Ohio, Avey's Run and Fox Run. SFM 3D reconstructions are built using images exported from 4K video shot at each field location. We demonstrate that SFM is a viable imaging approach for reconstructing cave passages with complex morphologies. We then use these reconstructions to create meshes upon which to run multiphysics simulations using STAR-CCM+. Our approach incorporates multiphase free-surface computational fluid dynamics simulations with sediment transport modeled using discrete element method grains. Physical and chemical properties of the water, bedrock, and sediment enable computation of shear stress, sediment impact forces, and chemical kinetic conditions at the bed surface. Preliminary results prove the efficacy of commercially

  16. Geology and preliminary hydrogeologic characterization of the cell-house site, Berlin, New Hampshire, 2003-04

    Science.gov (United States)

    Degnan, James R.; Clark, Stewart F.; Harte, Philip T.; Mack, Thomas J.

    2005-01-01

    At the cell-house site, thin, generally less than 20-foot thick overburden, consisting of till and demolition materials, overlies fractured crystalline bedrock. Bedrock at the site consists of gneiss with thin discontinuous lenses of chlorite schist and discontinuous tabular pegmatite. Two distinct fracture domains, with principal trends to the west and northwest, and to the north, overlap near the site. The cell-house site shows principal trends common to both domains. Gneiss is the most abundant rock at the site. Steeply dipping fractures within the gneiss terminate on subhorizontal contacts with pegmatite and on moderately dipping contacts with chlorite schist. Steeply northwest-dipping en Echelon fracture zones, parallel joint zones, and silicified brittle faults show consistent strikes to the northeast. Gently east-dipping to subhorizontal fractures, sub-parallel to gneissosity, strike northeast. The impermeable cap, barrier wall, and bedrock surface topography affect ground-water flow in the overburden. There is relatively little ground-water flow in the overburden in the capped area and a poor hydraulic connection between the overburden and the underlying bedrock over most of the site. The overburden beneath the cap may receive inflow through or beneath the barrier wall, or by flow through vertical fractures in the underlying bedrock beneath the barrier wall. The bedrock aquifer near the river is well connected to the river and head difference in the bedrock across the site are large (greater than 13 ft). Horizontal hydraulic conductivities of 0.2 to 20 ft/d were estimated for the bedrock. Individual fractures or fracture zones likely have hydraulic conductivities greater than the bulk rock. Subhorizontal fractures occur at pegmatite contacts or along chlorite schist lenses and may serve as ground-water conduits to the steeply dipping fractures in gneiss. The effective hydraulic conductivity across the site is likely to be in the low range of the estimated

  17. Enzyme leaching of surficial geochemical samples for detecting hydromorphic trace-element anomalies associated with precious-metal mineralized bedrock buried beneath glacial overburden in northern Minnesota

    Science.gov (United States)

    Clark, Robert J.; Meier, A.L.; Riddle, G.; ,

    1990-01-01

    One objective of the International Falls and Roseau, Minnesota, CUSMAP projects was to develop a means of conducting regional-scale geochemical surveys in areas where bedrock is buried beneath complex glacially derived overburden. Partial analysis of B-horizon soils offered hope for detecting subtle hydromorphic trace-element dispersion patterns. An enzyme-based partial leach selectively removes metals from oxide coatings on the surfaces of soil materials without attacking their matrix. Most trace-element concentrations in the resulting solutions are in the part-per-trillion to low part-per-billion range, necessitating determinations by inductively coupled plasma/mass spectrometry. The resulting data show greater contrasts for many trace elements than with other techniques tested. Spatially, many trace metal anomalies are locally discontinuous, but anomalous trends within larger areas are apparent. In many instances, the source for an anomaly seems to be either basal till or bedrock. Ground water flow is probably the most important mechanism for transporting metals toward the surface, although ionic diffusion, electrochemical gradients, and capillary action may play a role in anomaly dispersal. Sample sites near the Rainy Lake-Seine River fault zone, a regional shear zone, often have anomalous concentrations of a variety of metals, commonly including Zn and/or one or more metals which substitute for Zn in sphalerite (Cd, Ge, Ga, and Sn). Shifts in background concentrations of Bi, Sb, and As show a trend across the area indicating a possible regional zoning of lode-Au mineralization. Soil anomalies of Ag, Co, and Tl parallel basement structures, suggesting areas that may have potential for Cobalt/Thunder Baytype silver viens. An area around Baudette, Minnesota, which is underlain by quartz-chlorite-carbonate-altered shear zones, is anomalous in Ag, As, Bi, Co, Mo, Te, Tl, and W. Anomalies of Ag, As, Bi, Te, and W tend to follow the fault zones, suggesting potential

  18. Multi-isotope (carbon and chlorine) analysis for fingerprinting and site characterization at a fractured bedrock aquifer contaminated by chlorinated ethenes

    Energy Technology Data Exchange (ETDEWEB)

    Palau, Jordi, E-mail: jordi.palau@unine.ch [Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, Martí i Franquès, s/n 08028 Barcelona (Spain); Marchesi, Massimo [Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, Martí i Franquès, s/n 08028 Barcelona (Spain); Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Chambon, Julie C.C. [Department of Environmental Engineering, Technical University of Denmark, 2800 Lyngby (Denmark); Aravena, Ramon [Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Canals, Àngels [Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, Martí i Franquès, s/n 08028 Barcelona (Spain); Binning, Philip J.; Bjerg, Poul L. [Department of Environmental Engineering, Technical University of Denmark, 2800 Lyngby (Denmark); Otero, Neus; Soler, Albert [Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, Martí i Franquès, s/n 08028 Barcelona (Spain)

    2014-03-01

    The use of compound specific multi-isotope approach (C and Cl) in the characterization of a chlorinated ethenes contaminated fractured aquifer allows the identification of several sources and contaminant plumes, as well as the occurrence of biodegradation and mixing processes. The study site is located in Spain with contamination resulting in groundwater concentrations of up to 50 mg/L of trichloroethene (TCE), the most abundant chlorinated ethene, and 7 mg/L of tetrachloroethene (PCE). The potential sources of contamination including abandoned barrels, an underground tank, and a disposal lagoon, showed a wide range in δ{sup 13}C values from − 15.6 to − 40.5‰ for TCE and from − 18.5 to − 32.4‰ for PCE, allowing the use of isotope fingerprinting for tracing of the origin and migration of these contaminants in the aquifer. In contrast, there is no difference between the δ{sup 37}Cl values for TCE in the contaminant sources, ranging from + 0.53 to + 0.66‰. Variations of δ{sup 37}Cl and δ{sup 13}C in the different contaminant plumes were used to investigate the role of biodegradation in groundwater. Moreover, the isotopic data were incorporated into a reactive transport model for determination of whether the isotope pattern observed downstream from the tank's source could be explained by the simultaneous effect of mixing and biodegradation. The results demonstrate that a multi-isotope approach is a valuable tool for characterization of complex sites such as fractured bedrock aquifer contaminated by multiple sources, providing important information which can be used by consultants and site managers to prioritize and design more successful remediation strategies. - Highlights: • Origin and fate of CAHs in groundwater by means of multi CSIA ({sup 13}C,{sup 35}Cl) survey • Innovative/new approach tested in a fractured bedrock site • Differentiation of distinct CAH sources • Biodegradation and source mixing recognition in the aquifer.

  19. Bedrock cores from 89° North: Implications for the geologic framework and Neogene paleoceanography of Lomonosov Ridge and a tie to the Barents shelf

    Science.gov (United States)

    Grantz, Arthur; Pease, Victoria L.; Willard, Debra A.; Phillips, R.L.; Clark, David L.

    2001-01-01

    Two piston cores from the Eurasian flank of Lomonosov Ridge near lat 88.9°N, long 140°E provide the first samples of bedrock from this high-standing trans-Arctic ridge. Core 94-PC27 sampled nonmarine siltstone similar in facies and age to uppermost Triassic to lower Lower Jurassic and mid– Lower Cretaceous beds in the 4 to > 5 km Mesozoic section on Franz Josef Land, on the outer Barents shelf. A ca. 250 Ma peak in the cumulative frequency curve of detrital zircons from the siltstone, dated by U- Th-Pb analysis, suggests a source in the post-tectonic syenites of northern Taymyr and nearby islands in the Kara Sea. Textural trends reported in the literature indicate that the Lower Jurassic nonmarine strata of Franz Josef Land coarsen to the southeast; this suggests the existence of a sedimentary system in which detrital zircons could be transported from the northern Taymyr Peninsula to the outer Barents shelf near the position of core 94-PC27 prior to opening of the Eurasia Basin. Correlation of the coaly siltstone in core 94-PC27 with part of the Mesozoic section on Franz Josef Land is compatible with the strong evidence from seafloor magnetic anomalies and bathymetry that Lomonosov Ridge is a continental fragment rifted from the Barents shelf during the Cenozoic. It also suggests that Lomonosov Ridge near the North Pole is underlain by a substantial section of unmetamorphosed Mesozoic marine and nonmarine sedimentary strata. Core 94-PC29 sampled cyclical deposits containing ice-rafted debris (IRD) overlying weakly consolidated laminated olive-black anoxic Neogene siltstone and mudstone with an average total organic carbon (TOC) of 4.1 wt%. The high TOC content of the mudstone indicates that during the Neogene, prior to the introduction of IRD into the Arctic seas about 3.3 Ma (early late Pliocene), the shallow waters of the central Arctic Ocean supported significant primary photosynthetic organic production near the North Pole. These deposits also contain fine

  20. Environmental impacts of oil production on soil, bedrock, and vegetation at the U.S. Geological Survey Osage-Skiatook Petroleum Environmental Research site A, Osage County, Oklahoma

    Science.gov (United States)

    Otton, J.K.; Zielinski, R.A.; Smith, B.D.; Abbott, M.M.; Keeland, B.D.

    2005-01-01

    The U.S. Geological Survey is investigating the impacts of oil and gas production on soils, groundwater, surface water, and ecosystems in the United States. Two sites in northeastern Oklahoma (sites A and B) are presently being investigated under the Osage-Skiatook Petroleum Environmental Research project. Oil wells on the lease surrounding site A in Osage County, Oklahoma, produced about 100,000 bbl of oil between 1913 ard 1981. Prominent production features on the 1.5-ha (3.7-ac) site A include a tank battery, an oil-filled trench, pipelines, storage pits for both produced water and oil, and an old power unit. Site activities and historic releases have left open areas in the local oak forest adjacent to these features and a deeply eroded salt scar downslope from the pits that extends to nearby Skiatook Lake. The site is underlain by surficial sediments comprised of very fine-grained eolian sand and colluvium as much as 1.4 m (4.6 ft) thick, which, in turn, overlie flat-lying, fractured bedrock comprised of sandstone, clayey sandstone, mudstone, and shale. A geophysical survey of ground conductance and concentration measurements of aqueous extracts (1:1 by weight) of core samples taken in the salt scar and adjacent areas indicate that unusual concentrations of NaCl-rich salt are present at depths to at least 8 m (26 ft) in the bedrock; however, little salt occurs in the eolian sand. Historic aerial photographs, anecdotal reports from oil-lease operators, and tree-ring records indicate that the surrounding oak forest was largely established after 1935 and thus postdates the majority of surface damage at the site. Blackjack oaks adjacent to the salt scar have anomalously elevated chloride (>400 ppm) in their leaves and record the presence of NaCl-rich salt or salty water in the shallow subsurface. The geophysical measurements also indicate moderately elevated conductance beneath the oak forest adjoining the salt scar. Copyright ?? 2005. The American Association of

  1. Corrosion of copper in oxygen-deficient groundwater with and without deep bedrock micro-organisms: Characterisation of microbial communities and surface processes

    Energy Technology Data Exchange (ETDEWEB)

    Huttunen-Saarivirta, E., E-mail: elina.huttunen-saarivirta@vtt.fi [VTT Technical Research Centre of Finland, Materials Performance, Kemistintie 3, FI-02044 VTT (Finland); Rajala, P. [VTT Technical Research Centre of Finland, Materials Performance, Kemistintie 3, FI-02044 VTT (Finland); Bomberg, M. [VTT Technical Research Centre of Finland, Geobiotechnology, Tietotie 2, FI-02044 VTT (Finland); Carpén, L. [VTT Technical Research Centre of Finland, Materials Performance, Kemistintie 3, FI-02044 VTT (Finland)

    2017-02-28

    Highlights: • Copper was exposed to groundwater with and without deep bedrock micro-organisms. • Biofilm composition was determined and correlated with the behaviour of copper. • Under biotic conditions, the film of Cu{sub 2}S formed on copper surfaces. • Bacterial pool was in a key role for the morphology and properties of Cu{sub 2}S film. • Under abiotic conditions, Cu{sub 2}O systematically developed on copper surfaces. - Abstract: Copper specimens were exposed to oxygen-deficient artificial groundwater in the presence and absence of micro-organisms enriched from the deep bedrock of the planned nuclear waste repository site at Olkiluoto island on the western coast of Finland. During the exposure periods of 4 and 10 months, the copper specimens were subjected to electrochemical measurements. The biofilm developed on the specimens and the water used in the exposures were subjected to microbiological analyses. Changes in the water chemistry were also determined and surfaces of the copper specimens were characterized with respect to the morphology and composition of the formed corrosion products. The results showed that under biotic conditions, redox of the water and open circuit potential (OCP) of the copper specimens were generally negative and resulted in the build-up of a copper sulphide, Cu{sub 2}S, layer due to the activity of sulphate-reducing bacteria (SRB) that were included in the system. In the 4-month test, the electrochemical behaviour of the specimens changed during the exposure and alphaproteobactria Rhizobiales were the dominant bacterial group in the biofilm where the highest corrosion rate was observed. In the 10-month test, however, deltaproteobacteria SRB flourished and the initial electrochemical behaviour and the low corrosion rate of the copper were retained until the end of the test period. Under abiotic conditions, the positive water redox potential and specimen OCP correlated with the formation of copper oxide, Cu{sub 2}O

  2. Final disposal of high-level radioactive waste in deep boreholes. An evaluation based on recent research on the bedrock at great depths

    International Nuclear Information System (INIS)

    Aahaell, Karl-Inge

    2006-05-01

    New knowledge in hydrogeology and boring technology have opened the possibility to use deep boreholes as a repository for the Swedish high-level radioactive wastes. The determining property is that the repository can be housed in the stable bedrock at levels where the ground water has no contact with the biosphere and disposal and sealing can take place without disturbing the ground water stratification outside the disposal area. An advantage compared to a shallow repository of KBS-3 type, that is now being planned in Sweden, is that a borehole repository is likely to be technologically more robust, since the concept 'deep boreholes' seems to admit such a deep disposal that the entire disposal area would be surrounded by stable density-layered ground water, while a KBS-3 repository would be surrounded by moving ground water in contact with level close to the surface. This hydrological difference is of great importance for the safety in scenarios with leaching of radioactive substances. A deep repository is also less vulnerable for effects from natural events such as glaciation and earthquakes as well as from technological mishaps and terrorist actions. A crucial factor is, however, that the radioactive waste can be disposed of, in a secure way, at the intended depth, which will require new research and technology development

  3. A reconnaissance spatial and temporal assessment of methane and inorganic constituents in groundwater in bedrock aquifers, Pike County, Pennsylvania, 2012-13

    Science.gov (United States)

    Senior, Lisa A.

    2014-01-01

    Pike County in northeastern Pennsylvania is underlain by the Devonian-age Marcellus Shale and other shales, formations that have potential for natural gas development. During 2012–13, the U.S. Geological Survey in cooperation with the Pike County Conservation District conducted a reconnaissance study to assess baseline shallow groundwater quality in bedrock aquifers prior to possible shale-gas development in the county. For the spatial component of the assessment, 20 wells were sampled in summer 2012 to provide data on the occurrence of methane and other aspects of existing groundwater quality throughout the county, including concentrations of inorganic constituents commonly present at low levels in shallow, fresh groundwater but elevated in brines. For the temporal component of the assessment, 4 of the 20 wells sampled in summer 2012 were sampled monthly from July 2012 through June 2013 to provide data on seasonal variability in groundwater quality. All water samples were analyzed for major ions, nutrients, selected inorganic trace constituents (including metals and other elements), stable isotopes of water, radon-222, gross alpha- and gross beta-particle activity, dissolved gases (methane, ethane, and ethene), and, if possible, isotopic composition of methane. Additional analyses for boron and strontium isotopes, age-dating of water, and radium-226 were done on water samples collected from six wells in June 2013.

  4. Ground-penetrating radar and electrical resistivity tomography for mapping bedrock topography and fracture zones: a case study in Viru-Nigula, NE Estonia

    Directory of Open Access Journals (Sweden)

    Ivo Sibul

    2017-06-01

    Full Text Available The Geological Base Map (GBM, presenting an elongated buried valley running beneath the Varudi bog, triggered the geophysical studies near Viru-Nigula borough in northeastern Estonia. After the Geological Survey of Estonia had compiled the GBM map set, the course and extent of the valley still remained indistinct. Principally the morphology of the Varudi valley had been determined just by one borehole characterizing the 30 m thick Quaternary succession within the valley. The thickness of Quaternary sediments is, however, just a few metres in adjacent boreholes. We used ground-penetrating radar and electrical resistivity tomography (ERT for acquiring extra knowledge about the extent and morphology of the Varudi structure. Ground-penetrating radar enabled us to specify the thickness and composition of Quaternary deposits, and to recognize dislocations of the bedrock blocks. As the radar images provided information on the topmost ~4 m only, ERT (Wenner and Wenner–Schlumberger arrays was applied to define deeper, down to 40 m, electrical resistivity anomalies. The ERT studies revealed two fracture zones where regular Ordovician carbonate beds have been crushed and replaced by Quaternary sediments. The Varudi valley coincides with the southern zone. Both fracture zones probably acted as groundwater flow channels and sediment pathways in the Late Pleistocene, and hence supported the creation of the Varudi bog.

  5. BAT3 Analyzer: Real-Time Data Display and Interpretation Software for the Multifunction Bedrock-Aquifer Transportable Testing Tool (BAT3)

    Science.gov (United States)

    Winston, Richard B.; Shapiro, Allen M.

    2007-01-01

    The BAT3 Analyzer provides real-time display and interpretation of fluid pressure responses and flow rates measured during geochemical sampling, hydraulic testing, or tracer testing conducted with the Multifunction Bedrock-Aquifer Transportable Testing Tool (BAT3) (Shapiro, 2007). Real-time display of the data collected with the Multifunction BAT3 allows the user to ensure that the downhole apparatus is operating properly, and that test procedures can be modified to correct for unanticipated hydraulic responses during testing. The BAT3 Analyzer can apply calibrations to the pressure transducer and flow meter data to display physically meaningful values. Plots of the time-varying data can be formatted for a specified time interval, and either saved to files, or printed. Libraries of calibrations for the pressure transducers and flow meters can be created, updated and reloaded to facilitate the rapid set up of the software to display data collected during testing with the Multifunction BAT3. The BAT3 Analyzer also has the functionality to estimate calibrations for pressure transducers and flow meters using data collected with the Multifunction BAT3 in conjunction with corroborating check measurements. During testing with the Multifunction BAT3, and also after testing has been completed, hydraulic properties of the test interval can be estimated by comparing fluid pressure responses with model results; a variety of hydrogeologic conceptual models of the formation are available for interpreting fluid-withdrawal, fluid-injection, and slug tests.

  6. Delineation of fractures, foliation, and groundwater of the bedrock at a geothermal feasibility site on Roosevelt Island, New York County, New York

    Science.gov (United States)

    Stumm, Frederick; Chu, Anthony; Como, Michael D.; Noll, Michael L.; Joesten, Peter K.

    2015-01-01

    Advanced borehole-geophysical methods were used to investigate the hydrogeology of the crystalline bedrock in three boreholes on Roosevelt Island, New York County, New York. Cornell University was evaluating the feasibility of using geothermal energy for a future campus at the site. The borehole-logging techniques were used to delineate bedrock fractures, foliation, and groundwater-flow zones of the Fordham Gneiss in test boreholes at the site. Three fracture populations dominated by small (0.04 in or less) fractures were delineated in the three boreholes. A sub-horizontal population with low to moderate dipping fractures, a northeast dipping population with moderate to high angle fractures, and a small northwest dipping high angle fracture population. One large southwest dipping transmissive fracture underlies the entire study area with a mean dip azimuth of 235º southwest and a dip angle of 31º (N325ºW 31ºSW). The mean foliation dip azimuth was 296º northwest with a mean dip angle of 73º (N26ºE 73ºNW). Groundwater appears to flow through a network of fractures dominated by a large fracture underlying the site that is affected by tidal variations from the nearby East River. The total number of fractures penetrated by each borehole was 95, 63, and 68, with fracture indices of 0.26, 0.20, and 0.20 in GT-1 (NY292), GT-2 (NY293), and GT-3 (NY294), respectively. Aquifer test data indicate the specific capacity of boreholes GT-1 (NY292), GT-2 (NY293), and GT-3 (NY294) was 1.9, 1.5, and 3.7 gal/min/ft, respectively. The large contribution of flow from the leaking casing in borehole GT-3 (NY294) caused the doubling in specific capacity compared to boreholes GT-1 (NY292) and GT-2 (NY293). The transmissivities of the large fracture intersected by the three boreholes tested (GT-1, GT-2, and GT-3), calculated from aquifer-test analyses of time-drawdown data and flowmeter differencing, were 133, 124, and 65 feet squared per day (ft2/d), respectively. Gringarten

  7. Geophysical and hydrogeological characterisation of the impacts of on-site wastewater treatment discharge to groundwater in a poorly productive bedrock aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Donohue, Shane [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, Northern Ireland (United Kingdom); McCarthy, Valerie; Rafferty, Patrick [Department of Applied Sciences, Dundalk Institute of Technology, Dublin Road, Dundalk (Ireland); Orr, Alison; Flynn, Raymond [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, Northern Ireland (United Kingdom)

    2015-08-01

    Contaminants discharging from on-site wastewater treatment systems (OSWTSs) can impact groundwater quality, threatening human health and surface water ecosystems. Risk of negative impacts becomes elevated in areas of extreme vulnerability with high water tables, where thin unsaturated intervals limit vadose zone attenuation. A combined geophysical/hydrogeological investigation into the effects of an OSWTS, located over a poorly productive aquifer (PPA) with thin subsoil cover, aimed to characterise effluent impacts on groundwater. Groundwater, sampled from piezometers down-gradient of the OSWTS percolation area displayed spatially erratic, yet temporally consistent, contaminant distributions. Electrical resistivity tomography identified an area of gross groundwater contamination close to the percolation area and, when combined with seismic refraction and water quality data, indicated that infiltrating effluent reaching the water table discharged to a deeper more permeable zone of weathered shale resting on more competent bedrock. Subsurface structure, defined by geophysics, indicated that elevated chemical and microbiological contaminant levels encountered in groundwater samples collected from piezometers, down-gradient of sampling points with lower contaminant levels, corresponded to those locations where piezometers were screened close to the weathered shale/competent rock interface; those immediately up-gradient were too shallow to intercept this interval, and thus the more impacted zone of the contaminant plume. Intermittent occurrence of faecal indicator bacteria more than 100 m down gradient of the percolation area suggested relatively short travel times. Study findings highlight the utility of geophysics as part of multidisciplinary investigations for OSWTS contaminant plume characterisation, while also demonstrating the capacity of effluent discharging to PPAs to impact groundwater quality at distance. Comparable geophysical responses observed in similar

  8. Occurrence of geogenic contaminants in private wells from a crystalline bedrock aquifer in western Quebec, Canada: Geochemical sources and health risks

    Science.gov (United States)

    Bondu, Raphaël; Cloutier, Vincent; Rosa, Eric

    2018-04-01

    Nineteen private wells were investigated in order to evaluate the groundwater quality and the issues associated with well water use in a fractured metasedimentary aquifer of the Canadian Shield, in western Quebec (Canada). Groundwater sampling and analysis reveal that the quality of well water is both a potential aesthetic and health concern for the residents. Aesthetic problems are mainly related to the high levels of hardness and dissolved iron and manganese. Potential health risks are associated with the occurrence of brackish groundwater, high manganese concentrations, and arsenic concentrations exceeding the Canadian guideline value of 10 μg/l. Brackish groundwater is suspected to be derived from the mixing of fresh groundwaters with deep calcium-sodium-chloride brines of the Canadian Shield. The occurrences of iron, manganese and arsenic, primarily derived from the natural weathering of bedrock, are highly dependent on the geochemical conditions in groundwater, particularly the redox potential. Arsenic occurs mainly as arsenite (As(III)) and is thought to be released by the dissolution of iron and manganese oxyhydroxides under reducing conditions. Information obtained from well owners indicates that most households use ion exchange water softeners to minimize aesthetic problems of excessive hardness and dissolved iron and manganese concentrations. Homeowners generally take protective measures to reduce their exposure to arsenic when they are aware of the contamination. The exposure to arsenic and manganese may pose health risks for residents that do not take protective measures. The quality of well water is of paramount importance for human health in rural areas. Information on the contaminant sources and individual mitigation measures is essential to assess the health risks associated with groundwater consumption and to ensure the protection of public health.

  9. Preliminary report on mercury geochemistry of placer gold dredge tailings, sediments, bedrock, and waters in the Clear Creek restoration area, Shasta County, California

    Science.gov (United States)

    Ashley, Roger P.; Rytuba, James J.; Rogers, Ronald; Kotlyar, Boris B.; Lawler, David

    2002-01-01

    Clear Creek, one of the major tributaries of the upper Sacramento River, drains the eastern Trinity Mountains. Alluvial plain and terrace gravels of lower Clear Creek, at the northwest edge of the Sacramento Valley, contain placer gold that has been mined since the Gold Rush by various methods including dredging. In addition, from the 1950s to the 1980s aggregate-mining operations removed gravel from the lower Clear Creek flood plain. Since Clear Creek is an important stream for salmon production, a habitat restoration program is underway to repair damage from mining and improve conditions for spawning. This program includes using dredge tailings to fill in gravel pits in the flood plain, raising the concern that mercury lost to these tailings in the gold recovery process may be released and become available to biota. The purposes of our study are to determine concentrations and speciation of mercury in sediments, tailings, and water in the lower Clear Creek area, and to determine its mobility. Mercury concentrations in bedrock and unmined gravels both within and above the mined area are low, and are taken to represent background concentrations. Bulk mercury values in flood-plain sediments and dry tailings are elevated to several times these background concentrations. Mercury in sediments and tailings is associated with fine size fractions. Although methylmercury levels are generally low in sediments, shallow ponds in the flood plain may have above-normal methylation potential. Stream waters in the area show low mercury and methylmercury levels. Ponds with elevated methylmercury in sediments have more methylmercury in their waters as well. One seep in the area is highly saline, and enriched in mercury, lithium, and boron, similar to connate waters that are expelled along thrust faults to the south on the west side of the Sacramento Valley. This occurrence suggests that mercury in waters may at least in part be from sources other than placer mining.

  10. Fluoride abundance and controls in fresh groundwater in Quaternary deposits and bedrock fractures in an area with fluorine-rich granitoid rocks.

    Science.gov (United States)

    Berger, Tobias; Mathurin, Frédéric A; Drake, Henrik; Åström, Mats E

    2016-11-01

    This study focuses on fluoride (F(-)) concentrations in groundwater in an area in northern Europe (Laxemar, southeast Sweden) where high F(-) concentrations have previously been found in surface waters such as streams and quarries. Fluoride concentrations were determined over time in groundwater in the Quaternary deposits ("regolith groundwater"), and with different sampling techniques from just beneath the ground surface to nearly -700m in the bedrock (fracture) groundwater. A number of potential controls of dissolved F(-) were studied, including geological variables, mineralogy, mineral chemistry and hydrology. In the regolith groundwater the F(-) concentrations (0.3-4.2mg/L) were relatively stable over time at each sampling site but varied widely among the sampling sites. In these groundwaters, the F(-) concentrations were uncorrelated with sample (filter) depth and the water table in meters above sea level (masl), with the thicknesses of the groundwater column and the regolith, and with the distribution of soil types at the sampling sites. Fluoride concentrations were, however, correlated with the anticipated spatial distribution of erosional material (till) derived from a F-rich circular granite intrusion. Abundant release of F(-) from such material is thus suggested, primarily via dissolution of fluorite and weathering of biotite. In the fresh fracture groundwater, the F(-) concentrations (1.2-7.4mg/L) were generally higher than in the regolith groundwater, and were uncorrelated with depth and with location relative to the granite intrusion. Two mechanisms explaining the overall high F(-) levels in the fracture groundwater were addressed. First, weathering/dissolution of fluorite, bastnäsite and apophyllite, which are secondary minerals formed in the fractures during past hydrothermal events, and biotite which is a primary mineral exposed on fracture walls. Second, long water-residence times, favoring water-rock interaction and build-up of high dissolved F

  11. Role of river flow and sediment mobilization in riparian alder establishment along a bedrock-gravel river, South Fork Eel River, California

    Science.gov (United States)

    Jablkowski, P.; Johnson, E. A.; Martin, Y. E.

    2017-10-01

    Climatic, hydraulics, hydrologic, and fluvial geomorphic processes are the main drivers of riparian white alder (Alnus rhombifolia Nutt.) distribution in northern California. The Mediterranean climate and canyon bound, bedrock-gravel morphology of the South Fork Eel have a distinct effect on these processes. White alder seeds are preferentially deposited on river bars where river hydraulics create eddies coinciding with the downstream part of riffles and the upstream part of pools. Seeds are generally deposited below bankfull elevations by the descending hydrograph during the spring season in this Mediterranean climate. For successful germination and establishment, the seeds must be deposited at a location such that they are not remobilized by late spring flows. The summer establishment period is defined from the date of seed deposition and germination to the fall/winter date of river sediment mobilization. Seedling root growth rate decreases exponentially with decreasing water potential. However, seedlings are shown not to be generally limited by water availability at the elevations they are most commonly deposited. The establishment of white alder seedlings following the first summer will therefore depend on their ability to resist fall/winter high flows. The method proposed here compares the predicted rooting depth to predicted sediment scour rates. The length of the establishment period rather than water availability determines final seedling rooting depth. Over the past 40 years, very few years had establishment periods that were long enough or had fast enough alder growth rates to survive winter floods that often scour deeper than the total root length. The low survival of seedlings in the first autumn season following germination is believed to be a principal reason for the missing age classes often found in alder distributions along rivers.

  12. Condensate impacts in fractured bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Waddell, Jevins; Sandau, Court D.

    2011-06-15

    TRIUM Environmental Inc. was selected to conduct an investigation on the contamination of subsurface soils and groundwater on an active wellsite in Alberta. During this project, TRIUM characterized and delineated shallow soil impact. Once the baseline sites investigations was properly done, according to the site specifications they decided to use a pilot scale in-situ chemical oxidation (ISCO) to evaluate the fracture connectivity and verify if the technology would be efficient in reducing contaminants levels. The ISCO method provides a fast and complete mineralization of contaminants but it has to be used in appropriate sites and with the good chemical; in this case TRIUM selected a modified Fenton's reagent. This pilot showed that the fracture network was highly connected and that a good delivery of the oxidant could be achieved. This investigation highlighted that an accurate assessment is key to the success of remedial strategies and the results of the pilot have shown that ISCO was an appropriate method on this site.

  13. Site investigation SFR. Bedrock geology

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, Philip; Markstroem, Ingemar (Golder Associates AB (Sweden)); Petersson, Jesper (Vattenfall Power Consultant AB (Sweden)); Triumf, Carl-Axel; Isaksson, Hans; Mattsson, Haakan (GeoVista AB (Sweden))

    2011-12-15

    SKB is currently carrying out an assessment of the future extension of the final repository for low and middle level radioactive operational waste, SFR. The planned SFR extension lies at a relatively shallow depth (-50 to -200 masl) compared with the planned Forsmark facility for spent nuclear fuel (-400 to -500 masl). The main aim of the multidisciplinary modelling project involving geology, hydrogeology, hydrogeochemistry and rock mechanical modelling is to describe the rock volume for the planned extension of SFR that was presented in /SKB 2008a/. The results of the modelling project in the form of a forthcoming site descriptive model will supply the basis for site-adapted design including engineering characteristics, in addition to a general assessment of the site suitability. The current report presents the results of the geological work with the deterministic rock domain and deformation zone models (version 1.0) and forms a basis for the three other disciplines in the modelling work. The shallow depth of SFR and its proposed extension means that the facility lies partly within the rock volume affected by the effects of stress release processes during loading and unloading cycles, with an associated increased frequency of open sub-horizontal fractures in the near-surface realm (above -150 masl) compared with that observed at greater depths. The main report describes the data input to the modelling work, the applied modelling methodology and the overall results. More detailed descriptions of the individual modelled deformation zones and rock domains are included in the appendices. The geological modelling work during version 1.0 follows SKB's established methodology using the Rock Visualisation System (RVS). The deformation zone model version 1.0 is a further development of the previous version 0.1 /Curtis et al. 2009/. While the main input to deformation zone model version 0.1 was older geological data from the construction of SFR, including drawings of the geological tunnel mapping and eleven drill cores remapped according to the Boremap system, input to model version 1.0 has included the results from eight new cored boreholes as well as a fuller integration of Forsmark site investigation data, a further more extensive review of the drill core from an additional 32 boreholes associated with the construction of the existing SFR facility and an updated mapping of the lower construction tunnel. The current modelling work has also reviewed the older SFR data and models. While details concerning the earlier zones lying in immediate contact with the existing SFR facility have been changed, the earlier overall position, orientation and number of these deformation zones is maintained. A significant difference concerns their thickness due to the contrasting methodologies used during the different campaigns. In SFR model version 0.1, a single deformation zone model was produced, with a volume corresponding to the regional model volume. The model contained all the deformation zones modelled irrespective of size. Separate local and regional deformation zone models have been produced in SFR model version 1.0, following resolution criteria for the different model volumes. The local model contains zones with a minimum size of 300 m, while the regional model has structures that have a minimum size constraint of 1,000 m trace length at the ground surface. The selection of these size limits is related to the model volume maximum depth (local model -300 masl and regional model -1,000 masl) and the applied methodology that requires the same model resolution throughout the defined model volume (see Section 5.3.1). To assist hydrogeological modelling work, an updated combined model, including all structures from both the regional and local models, has also been delivered. The existing SFR facility and the rock volume directly to the south-east, which is proposed for the new facility extension, lies within a tectonic block that is bounded to the north-east and south-west by two broad belts of concentrated ductile and brittle deformation (Figures S-1 and S-2). The central block is less affected by deformation than the bounding belts. Within the central block, in the rock volume for the planned extension, a series of WNW-NW trending deformation zones are included in the local model (Figure S-2). These are much smaller than the bounding belts and were initiated at a later stage in a brittle regime. Even smaller zones with the same general strike and character, below the current model resolution, are inferred to permeate the entire rock volume. A NE to ENE striking set of brittle deformation zones is also present (Figure S-2). Compared with the WNW-NW set they are generally thinner and shorter, due to termination against the broad WNW-NW trending deformation belts

  14. Taste: The Bedrock of Flavor

    OpenAIRE

    Gary K Beauchamp

    2014-01-01

    The significance of taste for human health:Throughout most of human evolution, the daily decisions of what to put into ones mouth and swallow and what to reject presented challenges fraught with danger. Energy-rich foods were often difficult to find; protein was in short supply; sodium was scarce. Moreover, many plants that did contain nutrients were also equipped with defensive compounds that were poisonous. Now many humans over consume exactly the foods that they evolved to find particu...

  15. Taste: The Bedrock of Flavor

    Directory of Open Access Journals (Sweden)

    Gary K Beauchamp

    2014-07-01

    There are two general approaches to reducing dietary sodium. First, there is considerable interest in developing salt substitutes and salt enhancers. Potassium chloride is widely used (usually in combination with NaCl as a substitute but it is not ideal since many find it has an unpleasant off-taste. There is considerable academic and industry research to identify new substitutes but to date there are none for salty as there are for sweet taste. A second approach to lowering sodium intake on a population-wide level in the United States, where more than 80% of the average person’s salt intake comes from food purchased and not from being added during cooking or at the table, is for food manufacturers and restaurants to gradually reduce the amount of salt in prepared foods. Experimental studies have demonstrated that if one reduces salt intake preferences for salt are similarly reduced. Based on this, the Institute of Medicine (IOM recommended that the Food and Drug Administration require gradual reduction by food manufacturers and large restaurant chains (IOM. The FDA has not acted on this recommendation. Conclusion. As illustrated by the difficulties in reducing salt in spite of the health benefits (a similar set of arguments for reducing excess consumption of carbohydrate sugars could be made, the sense of taste is a powerful driver of food intake. A deeper understanding of this important but neglected sensory system is required if we are to adequately address critical health problems in modern society that are often driven by excess consumption of tasty nutrients.

  16. Bedrock geology and hydrostratigraphy of the Edwards and Trinity aquifers within the Driftwood and Wimberley 7.5-minute quadrangles, Hays and Comal Counties, Texas

    Science.gov (United States)

    Clark, Allan K.; Morris, Robert R.

    2017-11-16

    The Edwards and Trinity aquifers are major sources of water in south-central Texas and are both classified as major aquifers by the State of Texas. The population in Hays and Comal Counties is rapidly growing, increasing demands on the area’s water resources. To help effectively manage the water resources in the area, refined maps and descriptions of the geologic structures and hydrostratigraphic units of the aquifers are needed. This report presents the detailed 1:24,000-scale bedrock hydrostratigraphic map as well as names and descriptions of the geologic and hydrostratigraphic units of the Driftwood and Wimberley 7.5-minute quadrangles in Hays and Comal Counties, Tex.Hydrostratigraphically, the rocks exposed in the study area represent a section of the upper confining unit to the Edwards aquifer, the Edwards aquifer, the upper zone of the Trinity aquifer, and the middle zone of the Trinity aquifer. In the study area, the Edwards aquifer is composed of the Georgetown Formation and the rocks forming the Edwards Group. The Trinity aquifer is composed of the rocks forming the Trinity Group. The Edwards and Trinity aquifers are karstic with high secondary porosity along bedding and fractures. The Del Rio Clay is a confining unit above the Edwards aquifer and does not supply appreciable amounts of water to wells in the study area.The hydrologic connection between the Edwards and Trinity aquifers and the various hydrostratigraphic units is complex because the aquifer system is a combination of the original Cretaceous depositional environment, bioturbation, primary and secondary porosity, diagenesis, and fracturing of the area from Miocene faulting. All of these factors have resulted in development of modified porosity, permeability, and transmissivity within and between the aquifers. Faulting produced highly fractured areas which allowed for rapid infiltration of water and subsequently formed solutionally enhanced fractures, bedding planes, channels, and caves that

  17. Microbiology of transitional groundwater of the porous overburden and underlying shallow fractured bedrock aquifers in Olkiluoto, Finland. October 2005 - January 2006

    International Nuclear Information System (INIS)

    Pedersen, K.

    2007-05-01

    The subsurface biosphere on Earth appears to be far more expansive and metabolically and phylogenetically complex than previously thought. A diverse suite of subsurface environments has been reported to support microbial ecosystems, extending from a few meters below the surface to several thousand meters. The discovery of a deep biosphere will have several important implications for underground repositories for radioactive wastes. The main potential effects of microorganisms in the context of a KBS-3 type repository for spent fuel in the bedrock of Olkiluoto are: (1) Oxygen reduction and maintenance of anoxic and reduced conditions. (2) Bio-immobilisation and bio-mobilisation of radionuclides, and the effects from microbial metabolism on radionuclide mobility. (3) Sulphate reduction to sulphide and the risk for copper sulphide corrosion. The main objective of this study was to characterize the geochemistry, biomass and microbial diversity of shallow subsurface groundwater at Olkiluoto, from 4.0 m down to 14.9 m. This objective also permitted the determination of whether or not there is any transition in the shallow depths at Olkiluoto to microbial conditions associated with the deep subsurface. This was the second investigation that covered both shallow and some moderately deep groundwater microbiology in Olkiluoto. The analysis of microbiology is very important for proper understanding of the evolution of geochemical processes in and around the underground research facility ONKALO being constructed at Olkiluoto by Posiva since autumn 2004, as well as for the planned KBS-3 type spent fuel repository at Olkiluoto. There are several conclusions from this investigation that are of importance for ONKALO. The following present day conclusions can be drawn. Continued investigations will update and test them: The shallow biosphere was dominated by oxygen consuming microorganisms that block oxygen migration to deeper groundwater. This effect was most pronounced during the

  18. Bedrock assemblages of the Bering Strait region: Implications for offshore metal sources in the marine environment: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998

    Science.gov (United States)

    Hudson, Travis L.; Saltus, Richard W.

    2000-01-01

    The Bering Strait region is important habitat for Pacific walrus (Odobenus rosmarus divergens). Elevated metal levels in tissues of some walrus have raised concerns about the sources of these metals. This study synthesizes and integrates onshore geology, regional gravity and magnetic data, and information about mineral deposits and the natural processes that weather, erode, and disperse metals in the Bering Strait region. In this region (Seward Peninsula, St. Lawrence Island, Chukotsk Peninsula, and intervening areas of the Bering Sea shelf), six bedrock assemblages can be defined and extended from onshore to offshore areas. These assemblages include (1) Paleozoic sedimentary and low-grade metasedimentary rocks, (2) upper Paleozoic to Triassic sedimentary and related mafic igneous rocks, (3) Mesozoic high-pressure, low-temperature metamorphic rocks, (4) Cretaceous amphibolite-facies metamorphic rocks, (5) Cretaceous volcanic and related intrusive rocks, and (6) Tertiary sedimentary and volcanic rocks. Cretaceous plutonic rocks are widely scattered and locally intrude all of the pre-Tertiary bedrock assemblages. The distribution and thickness of Tertiary sedimentary rocks can be approximated in offshore areas using satellite gravity data. The resulting new map shows that about 40 percent of the offshore Bering Strait region may have bedrock at or near the sea floor. Some mineral deposits and rock units with high background metal contents are associated with specific bedrock assemblages whereas other mineral deposits are more regionally distributed. The mineral deposits of the region are mostly types that contain Cu, Pb, Zn, Ag, Mo, Sn, or Au (or certain combinations of these metals) and elevated concentrations of associated elements, such as As, Bi, Be, B, Sb, and F. The mineral deposits have been physically and chemically weathered and eroded by both subaerial and marine processes. Marine processes have been particularly important as the region has experienced

  19. From source to sink: Unravelling the complex in situ cosmogenic 10Be-14C signature in eroding bedrock surfaces and river sediment from the Bolivian Altiplano

    Science.gov (United States)

    Hippe, Kristina; Lupker, Maarten; Gordijn, Tiemen; Ivy-Ochs, Susan; Kober, Florian; Christl, Marcus; Wacker, Lukas; Hajdas, Irka; Wieler, Rainer

    2017-04-01

    Sediment storage is a critical component of fluvial sedimentary systems. By interrupting transport processes, intermittent sediment storage can effectively decouple source from sink and buffer the transmission of signals of environmental change (e.g., in climate, vegetation, human impact) through the fluvial system. Combined in situ cosmogenic 14C-10Be analysis in fluvial sediment provides a unique method to simultaneously assess sediment transit times (in situ 14C signal) and long-term sediment production rates from bedrock erosion (10Be signal). The key is the much shorter half-life of in situ 14C compared to 10Be which causes a rapid decrease of the in situ 14C concentration when sediment is buried during sediment storage and creates an offset to 10Be. Here, we use the in situ 14C-10Be chronometer to determine changes in surface erosion and estimate absolute rates of sediment transfer in a catchment on the Bolivian Altiplano. Previous research in the study area has found a significant offset in the in situ 14C-10Be inventories from river sediments with much lower in situ 14C concentrations than expected from the 10Be content for steady-state conditions. This offset has been interpreted to reflect sediment storage over the past 11-20 ka [1]. Additional analyses of in situ 14C and 10Be in a dense network of sediment samples from the main channel and tributaries agree with previous data and yield very low in situ 14C concentrations that suggest an increase in storage duration by a few ka with downstream distance. However, analyses of in situ 14C-10Be in hilltop samples from the eroding source area reveal an almost as large offset as in the river sediments. Such complex in situ 14C-10Be inventories in the source area have a severe impact on the quantification of sediment storage times and strongly challenge previous data interpretation. The most straightforward explanation for the in situ 14C-10Be offset at hilltop locations is a change in denudation rate during the

  20. Bedrock geology Forsmark. Modelling stage 2.3. Implications for and verification of the deterministic geological models based on complementary data

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, Michael B. (Geological Survey of Sweden, Uppsala (Sweden)); Simeonov, Assen (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Isaksson, Hans (GeoVista AB, Luleaa (Sweden))

    2008-12-15

    The Swedish Nuclear Fuel and Waste Management Company is in the process of completing site descriptive modelling at two locations in Sweden, with the objective to site a deep geological repository for spent nuclear fuel. At Forsmark, the results of the stage 2.2 geological modelling formed the input for downstream users. Since complementary ground and borehole geological and geophysical data, acquired after model stage 2.2, were not planned to be included in the deterministic rock domain, fracture domain and deformation zone models supplied to the users, it was deemed necessary to evaluate the implications of these stage 2.3 data for the stage 2.2 deterministic geological models and, if possible, to make use of these data to verify the models. This report presents the results of the analysis of the complementary stage 2.3 geological and geophysical data. Model verification from borehole data has been implemented in the form of a prediction-outcome test. The stage 2.3 geological and geophysical data at Forsmark mostly provide information on the bedrock outside the target volume. Additional high-resolution ground magnetic data and the data from the boreholes KFM02B, KFM11A, KFM12A and HFM33 to HFM37 can be included in this category. Other data complement older information of identical character, both inside and outside this volume. These include the character and kinematics of deformation zones and fracture mineralogy. In general terms, it can be stated that all these new data either confirm the geological modelling work completed during stage 2.2 or are in good agreement with the data that were used in this work. In particular, although the new high-resolution ground magnetic data modify slightly the position and trace length of some stage 2.2 deformation zones at the ground surface, no new or modified deformation zones with a trace length longer than 3,000 m at the ground surface have emerged. It is also apparent that the revision of fracture orientation data

  1. Mercury Geochemistry of Gold Placer Tailings, Sediments, Bedrock, and Waters in the Lower Clear Creek Area, Shasta County, California - Report of Investigations, 2001-2003

    Science.gov (United States)

    Ashley, Roger P.; Rytuba, James J.

    2008-01-01

    Clear Creek, one of the major tributaries of the upper Sacramento River, drains the eastern Trinity Mountains. Alluvial plain and terrace gravels of lower Clear Creek, at the northwest edge of the Sacramento Valley, contain placer gold that has been mined since the Gold Rush by various methods including hydraulic mining and dredging. In addition, from the 1950s to the 1980s aggregate-mining operations removed gravel from the lower Clear Creek flood plain. Since Clear Creek is an important stream for salmon production, a habitat restoration program is underway to repair damage from mining and improve conditions for spawning. This program includes moving dredge tailings to increase the area of spawning gravel and to fill gravel pits in the flood plain, raising the concern that mercury lost to these tailings in the gold recovery process may be released and become available to biota. The purposes of our study are to identify sources, transport, and dispersal of mercury in the lower Clear Creek area and identify environments in which bioavailable methylmercury is produced. Analytical data acquired include total mercury and methylmercury concentrations in sediments, tailings, and water. Mercury concentrations in bedrock and unmined gravels in and around the mined area are low and are taken to represent background concentrations. Bulk mercury values in placer mining tailings range from near-background in coarse dry materials to more than 40 times background in sands and silts exposed to mercury in sluices. Tailings are entrained in flood-plain sediments and active stream sediments; consequently, mercury concentrations in these materials range from background to about two to three times background. Mercury in sediments and tailings is associated with fine size fractions. The source of most of this mercury is historical gold mining in the Clear Creek watershed. Although methylmercury levels are low in most of these tailings and sediments, flood-plain sediment in shallow

  2. Bedrock geology Forsmark. Modelling stage 2.3. Implications for and verification of the deterministic geological models based on complementary data

    International Nuclear Information System (INIS)

    Stephens, Michael B.; Simeonov, Assen; Isaksson, Hans

    2008-12-01

    The Swedish Nuclear Fuel and Waste Management Company is in the process of completing site descriptive modelling at two locations in Sweden, with the objective to site a deep geological repository for spent nuclear fuel. At Forsmark, the results of the stage 2.2 geological modelling formed the input for downstream users. Since complementary ground and borehole geological and geophysical data, acquired after model stage 2.2, were not planned to be included in the deterministic rock domain, fracture domain and deformation zone models supplied to the users, it was deemed necessary to evaluate the implications of these stage 2.3 data for the stage 2.2 deterministic geological models and, if possible, to make use of these data to verify the models. This report presents the results of the analysis of the complementary stage 2.3 geological and geophysical data. Model verification from borehole data has been implemented in the form of a prediction-outcome test. The stage 2.3 geological and geophysical data at Forsmark mostly provide information on the bedrock outside the target volume. Additional high-resolution ground magnetic data and the data from the boreholes KFM02B, KFM11A, KFM12A and HFM33 to HFM37 can be included in this category. Other data complement older information of identical character, both inside and outside this volume. These include the character and kinematics of deformation zones and fracture mineralogy. In general terms, it can be stated that all these new data either confirm the geological modelling work completed during stage 2.2 or are in good agreement with the data that were used in this work. In particular, although the new high-resolution ground magnetic data modify slightly the position and trace length of some stage 2.2 deformation zones at the ground surface, no new or modified deformation zones with a trace length longer than 3,000 m at the ground surface have emerged. It is also apparent that the revision of fracture orientation data

  3. Combining outcrop, magnetic, and airborne LiDAR data in a course-based undergraduate research experience (CURE): interpretation of bedrock fracturing in the northeastern Deep River Basin and adjacent basement, North Carolina

    Science.gov (United States)

    Pedigo, R.; Waters-Tormey, C. L.; Styers, D.; Hurst, E.

    2017-12-01

    Course-based undergraduate research experiences (CUREs) are a way for students to learn the power of combining geological, geophysical, and geodetic datasets, while also generating new results to answer real questions. A 5-week undergraduate geophysics CURE combined newly released public domain LiDAR-derived ground models with outcrop and magnetic data. The goal was to see if this approach could improve understanding of bedrock fracture sets in the NC Piedmont, which in turn would improve decisions about groundwater resources and proposed hydraulic fracturing of "tight" shale reservoirs in the 230 Ma Deep River failed rift basin. The 10 km2 study area was selected because it straddles the fault contact between crystalline basement and basin sedimentary rocks, it contains 200 Ma NW-SE trending mafic dikes related to successful rifting of Pangea common in the Piedmont, bedrock exposure is typical of the Piedmont (poor), and its land use history is representative of much of the Piedmont. Students visited representative field sites to collect observations then manually identified lineaments in several adjacent LiDAR ground model tiles. Results suggest that (1) lineaments as short as a few m are easily identified except underneath Quaternary deposits, (2) the dominant lineament set trends NW-SE with m- to 10 m-scale spacing, (3) lineaments are better expressed in sedimentary rocks and (4) do not spatially coincide with dike traces. Using field observations, map patterns, and total magnetic intensity profiles across several dikes, the lineaments are interpreted to be edges of subvertical joint fractures recording extension parallel to the dikes' dilation direction. The CURE concluded with students in small groups proposing next steps for the larger research project. The CURE introduced geology majors to the power of using geophysical and remote sensing data with geological data to address geoscience questions. Student feedback was very positive even though the learning

  4. Influence of a tectonically active mountain belt on its foreland basin: Evidence from detrital zircon dating of bedrocks and sediments from the eastern Tibetan Plateau and Sichuan Basin, SW China

    Science.gov (United States)

    Zhong, Ning; Song, Xiangsuo; Xu, Hongyan; Jiang, Hanchao

    2017-09-01

    The tectonically active eastern Tibetan Plateau (TP) impacts the populous Sichuan Basin in the form of dust and exhumed detrital materials. To better understand a detailed transport process of detrital material from the eastern TP to the Sichuan Basin, eight samples were collected from the upper reaches of the Min River in the eastern TP to the Sichuan Basin, for zircon U-Pb chronological and grain-size analysis. The results are compared with those of previously studies. Zircon grains are comparatively coarse in three bedrock samples, one fluvial sand sample and one dust sample, but are distinctly fine in three lacustrine samples. Intriguingly, the zircon grain-size parameters from the fluvial sand and dust samples are similar to each other. Consistent with previous studies of this area, the analysis of our U-Pb zircon ages indicates five major age populations at 180-350 Ma, 350-550 Ma, 700-1000 Ma, 1600-2000 Ma, and 2200-2600 Ma, which broadly correspond to five known granitoid magmatic events within the Yangtze Block. The Min River links lacustrine sediments from Lixian, fluvial sands from Wenchuan, Leshan, Yibin, and from the Dadu River and the Dayi conglomerate, implying the Dayi conglomerate was transported by fluvial rather than glacial processes. The denuded detrital material, mainly generated by seismic events in the eastern TP, was transported by water flow into the western Sichuan Basin, where two thick sedimentary depocenters developed, and the relatively fine grains were then transported by wind to the northern Sichuan Basin. Thus, the thick sediments in the western Sichuan Basin mainly transported by the Min River probably exerted a major influence on dust deposition in the northern Sichuan Basin. In contrast, the Jialing and Dadu rivers made a minor contribution.

  5. Thermal guidelines for a repository in bedrock

    Energy Technology Data Exchange (ETDEWEB)

    1976-09-01

    The findings of a study conducted to develop general thermal guidelines for the underground storage of canisters containing high level nuclear waste are summarized. The report contains general thermal guidelines for spacing canisters in three types of rock: shale, limestone, and granite; a survey of thermophysical rock properties and rock mechanical behavior; and a recommended approach for determining rigorously the thermal design criteria for the storage facility. This recommended approach would couple rock mechanics and thermal considerations in a transient, finite element model capable of simulating the excavation and canister emplacement sequence. In recognition of the nascent stage of the waste storage program, this report concludes with suggestions for future research and for future analytical and experimental efforts. The canisters of nuclear waste will produce significant quantities of heat from radioactive decay. The storage facility, therefore, must be designed in a manner that will permit this heat to be dissipated safely and efficiently. Crucial to this design is proper canister pitch. The two major constraints on canister pitch are the maximum allowable temperature of the stored nuclear waste and the overall structural integrity of the underground facility.

  6. Predicting Scour of Bedrock in Wisconsin

    Science.gov (United States)

    2017-04-01

    This research evaluates the scour potential of rocks supporting Wisconsin DOT bridge foundations. Ten highway bridges were selected for this study, of which seven are supported by shallow foundations, and five were built on sandstone in rivers/stream...

  7. Bauxite formation on Proterozoic bedrock of Suriname

    NARCIS (Netherlands)

    Monsels, Dewany A.; van Bergen, Manfred J.

    Lateritic bauxite deposits in Suriname rest on a variety of metamorphic, igneous and sedimentary parent rocks. Remnants of multiple planation surfaces with duricrusts that mark the tropical landscape are associated with recurrent episodes of bauxite formation since Late Cretaceous times.

  8. Chemistry of deep groundwaters from granitic bedrock

    International Nuclear Information System (INIS)

    Allard, B.; Larsson, S.Aa.; Tullborg, A.L.; Wikberg, P.

    1983-05-01

    Water analysis data from Fjaellveden, Gideaa, Svartboberget and Kamlunge (7 different drilling holes, 26 sampling levels at vertical depths between 100 and 600 m) are discussed. Most of the waters are Na(sup)+ -Ca 2 (sup)+ -HCO 3 (sup)- -dominated with a total salt content of 200-300 mg/1 and pH of 8-9. Intrusions of Na(sup)+ -Cl(sup)- -dominated saline waters (up to 650 mg/1) are observed at great depth. The conditions are generally strongly reducing. The presence of clayish material (kaolinite, smectities) and zeolites in the fractures appears to have a large influence on the cation concentration ratios. The contents of organics, largely fulvic acids of intermediate molecular weight ( 18 0 and deuterium) indicate a non-marine origin of the water and only minor exchanges with the surroundings. The presence of tritium is evidence of intrusions of young waters in some of the samples, probably due to the disturbances during drilling and sampling. (author)

  9. Waste-rock interactions and bedrock reactions

    International Nuclear Information System (INIS)

    White, W.B.

    1977-01-01

    The experimental program is designed to discover possible reactions between shale repository rocks and radioactive wastes. The canister can be regarded in three ways: (a) As a source of heat that modifies the mineralogy and therefore the physical properties of the surrounding rock (dry heat). (b) As a source of heat that activates reactions between minerals in the surrounding rock and slowly percolating ground water. (c) As a source of reaction materials of different composition from the surrounding rock and which therefore may react to form completely new ''minerals'' in a contact aureole around the canister. The matrix of interactions contains two composition axes. The waste compositions are defined by the various prototype waste forms usually investigated: glass, calcine, ''spent fuel'' and the ceramic supercalcine. The temperatures and pressures at which these reactions take place must be investigated. Thus each node on the ''wiring diagram'' is itself a matrix of experiments in which the T and to some extent P are varied. Experiments at higher pressure and temperature allow reactions to take place on a laboratory time scale and thus identify what could happen. These reactions are then followed downward in temperature to determine both phase boundaries and kinetic cut-offs below which equilibrium cannot be achieved on a laboratory time scale

  10. The generative bedrock of open design

    NARCIS (Netherlands)

    Avital, M.; van Abel, B.; Klaassen, R.; Evers, L.; Troxler, P.

    2011-01-01

    A shift in communications infrastructure is an important factor in how open design has taken shape and the possibilities it offers. It is a transition from the ‘internet of things’ to the things of the internet. Michel Avital analyses the main drivers behind open design, open innovation and open

  11. U-Th disequilibria constraints on physical and chemical erosion processes and rates in soils from the Lake Natron-Lake Magadi (Gregory Rift Valley) drainage area vs hydrology/paleohydrology and bedrock lithology

    Science.gov (United States)

    Hillaire-Marcel, Claude

    2015-04-01

    This presentation is a tribute to my former PhD student, the late Dr. Christian Goetz (1960-1991), who carried out intensive field and laboratory investigations on actinides in soils and sediments from lakes Manyara and Natron (Tanzania), and Magadi (Kenya) during his doctoral studies. Soils developed on granites from the Precambrian plateau, west of Gregory Rift, as well as those developed on the trachitic floor of the Rift yield nearly similar patterns, with U-leached (and Th-enriched) upper horizons vs source rocks. They differ from each other by i) the much higher [U]/[Th] mass ratio of soil over the granitic (~ 0.3) vs the trachitic (~ 0.1) basements (both near secular equilibrium), and ii) the greater decay of 230Th-excesses (230Thxs) in top soils over trachites, pointing to much older soils and/or lower leaching rates at the Rift floor. This difference seems related to the more arid conditions prevailing in the deeper part of the Rift. In contrast, soils developed on the basaltic walls of the Rift, characterized by abundant spring water from the basalt aquifer and a dense vegetation, depict a three-stage U-Th isotope evolution, with bedrock at near secular radioactive equilibrium and a [U]/[Th] ratio of ~ 0.2. It is overlain by a U-depleted horizon (with up to 75% relative losses in U), then topped by a low Eh, organic-matter rich layer, with evidence for a secondary uptake of U. The high 230Thxs observed in the U-leached horizon point to relatively fast U-leaching rates and/or "young" soil pattern. The present-day clays deposited in Lake Natron point to a Precambrian granitic plateau origin (through major rivers flowing eastwards towards the lake), whereas clay supplies from the rift escarpment basalts are carried with hydrothermal seepages towards Lake Magadi. U-Th measurements in early diagenetic minerals (phosphates) and clays (smectites) deposited during late Pleistocene high-lake levels (≥ 12 ka BP) provide robust constraints on source-rocks and

  12. Stem Cells

    Science.gov (United States)

    Stem cells are cells with the potential to develop into many different types of cells in the body. They serve as a repair ... body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

  13. Final disposal of high-level nuclear waste in very deep boreholes. An evaluation based on recent research of bedrock conditions at great depths; Slutfoervaring av hoegaktivt kaernavfall i djupa borrhaal. En utvaerdering baserad paa senare aars forskning om berggrunden paa stora djup

    Energy Technology Data Exchange (ETDEWEB)

    Aahaell, Karl-Inge [Karlstad Univ. (Sweden)

    2007-01-15

    This report evaluates the feasibility of very deep borehole disposal of high-level nuclear waste, e.g., spent nuclear fuel, in the light of recent technological developments and research on the characteristics of bedrock at extreme depths. The evaluation finds that new knowledge in the field of hydrogeology and technical advances in drilling technology have advanced the possibility of using very deep boreholes (3-5 km) for disposal of the Swedish nuclear waste. Decisive factors are (1) that the repository can be located in stable bedrock at a level where the groundwater is isolated from the biosphere, and (2) that the waste can be deposited and the boreholes permanently sealed without causing long-term disturbances in the density-stratification of the groundwater that surrounds the repository. Very deep borehole disposal might offer important advantage compared to the relatively more shallow KBS approach that is presently planned to be used by the Swedish nuclear industry in Sweden, in that it has the potential of being more robust. The reason for this is that very deep borehole disposal appears to permit emplacement of the waste at depths where the entire repository zone would be surrounded by stable, density-stratified groundwater having no contact with the surface, whereas a KBS-3 repository would be surrounded by upwardly mobile groundwater. This hydro-geological difference is a major safety factor, which is particularly apparent in all scenarios that envisage leakage of radioactive substances. Another advantage of a repository at a depth of 3 to 5 km is that it is less vulnerable to impacts from expected events (e.g., changes in groundwater conditions during future ice ages) as well as undesired events (e.g. such as terrorist actions, technical malfunction and major local earthquakes). Decisive for the feasibility of a repository based on the very deep borehole concept is, however, the ability to emplace the waste without failures. In order to achieve this

  14. Cell-cell channels

    National Research Council Canada - National Science Library

    Baluška, F; Volkmann, Dieter; Barlow, P. W

    2006-01-01

    ...-Negative Bacteria Pheromone-Responsive Conjugative Plasmids in E. faecalis Nonpheromone-Responsive Plasmids in G+ Bacteria 21 22 27 28 Section II: Ciliate Cells 3. The Tetrahymena Conjugation Ju...

  15. Fuel cells

    Science.gov (United States)

    Hooie, D. T.; Harrington, B. C., III; Mayfield, M. J.; Parsons, E. L.

    1992-07-01

    The primary objective of DOE's Fossil Energy Fuel Cell program is to fund the development of key fuel cell technologies in a manner that maximizes private sector participation and in a way that will give contractors the opportunity for a competitive posture, early market entry, and long-term market growth. This summary includes an overview of the Fuel Cell program, an elementary explanation of how fuel cells operate, and a synopsis of the three major fuel cell technologies sponsored by the DOE/Fossil Energy Phosphoric Acid Fuel Cell program, the Molten Carbonate Fuel Cell program, and the Solid Oxide Fuel Cell program.

  16. Levels of potassium, uranium, thorium and rate of radiogenic heat production in the bedrock adjacent to Camamu and Almada sedimentary basins, Bahia, Brazil; Teores de potassio, uranio, torio e taxa de producao de calor radiogenico no embasamento adjacente as bacias sedimentares de Camamu e Almada, Bahia, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Sapucaia, Najara Santos; Barbosa, Johildo Salomao Figueiredo [Instituto de Geociencias, Universidade Federal da Bahia, Salvador, BA (Brazil); Argollo, Roberto Max de, E-mail: nss@cpgg.ufba.br, E-mail: johildo@cpgg.ufba.br, E-mail: robmax@ufba.br [Laboratorio de Fisica Nuclear Aplicada, Instituto de Fisica, Universidade Federal da Bahia, Salvador, BA (Brazil)

    2005-10-15

    The bedrock adjacent to Camamu and Almada sedimentary basins is characterized mainly by rocks of granulite and amphibolite facies, with archaean and paleoproterozoic ages, which belong to orogen Itabuna-Salvador-Curaca. The units in major proportion in this context are the metatonalites associated with basic and metamonzonites belonging to Itabuna belt. In smaller area occur the Teolandia granite and the Moenda granodiorite associated with the Ipiau band amphibolites, the charnockites and charnoenderbites of Jequie bloc, the neoproterozoic sienites and the mafic dikes. The K, U and Th contents of the rocks vary from 0,02 to 6,33% for K, from < 0,2 to 9,10 ppm for U and from < 0,4 to 64,38 ppm for Th. These contents are higher in the charnockites, Moenda granodiorite, Teolandia granite and sienites, intermediate in the metatonalites and metamonzonites and lower in the basic granulites. The heat production rates are higher in the lithologies where K, U and Th are also higher, varying from 0,58 to 5,57 {mu}W m{sup -3}. The coverage areas of such lithologies are, however, small compared with that of the metatonalitic granulites, metamonzonitic granulites and sienites where the rates vary from 0,10 to 1,44 {mu}W m{sup -3}, 0,23 to 5,55 {mu}W m{sup -3} and 0,60 to 2,24 {mu}W m{sup -3}, respectively. In this case, the heat production rates vary from 0,10 to 1,44 {mu}W m{sup -3}. The basic granulites have the smaller rates, from 0,06 to 0,36 {mu}W m-3. The observation of the lithologies in the margins of the two basins suggest that, in the bedrock under the younger sediments, may predominate the metatonalites, followed by the metamonzonites, with some significant participation of sienites in the Almada basin. In those lithologies, the volumetric heat production rates, with one standard deviation range, are 0,41 +- 0,30 {mu}W m{sup -3} for metatonalites, 0,71 +- 0,57 {mu}W m{sup -3} for metamonzonites and 1,20 +- 0,51 {mu}W m{sup -3} for sienites. (author)

  17. Delineation of areas having elevated electrical conductivity, orientation and characterization of bedrock fractures, and occurrence of groundwater discharge to surface water at the U.S. Environmental Protection Agency Barite Hill/Nevada Goldfields Superfund site near McCormick, South Carolina

    Science.gov (United States)

    Chapman, Melinda J.; Huffman, Brad A.; McSwain, Kristen Bukowski

    2015-07-16

    During October 2012 through March 2013, the U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (EPA) Region 4, Superfund Section, conducted borehole geophysical logging, surface geophysical surveys, and water-quality profiling in selected wells and areas to characterize or delineate the extent of elevated subsurface electrical conductivity at the EPA Barite Hill/Nevada Goldfields Superfund site near McCormick, South Carolina. Elevated electrical conductivity measured at the site may be related to native rock materials, waste rock disposal areas used in past operations, and (or) groundwater having elevated dissolved solids (primarily metals and major ions) related to waste migration. Five shallow screened wells and four open-borehole bedrock wells were logged by using a suite of borehole tools, and downhole water-quality profiles were recorded in two additional wells. Well depths ranged from about 26 to 300 feet below land surface. Surface geophysical surveys based on frequency-domain electromagnetic and distributed temperature sensing (DTS) techniques were used to identify areas of elevated electrical conductivity (Earth materials and groundwater) and potential high dissolved solids in groundwater and surface water on land and in areas along the northern unnamed tributary at the site.

  18. Final disposal of high-level radioactive waste in deep boreholes. An evaluation based on recent research on the bedrock at great depths; Slutfoervaring av hoegaktivt kaernavfall i djupa borrhaal. En utvaerdering baserad paa senare aars forskning om berggrunden paa stora djup

    Energy Technology Data Exchange (ETDEWEB)

    Aahaell, Karl-Inge [Karlstad Univ. (Sweden)

    2006-05-15

    New knowledge in hydrogeology and boring technology have opened the possibility to use deep boreholes as a repository for the Swedish high-level radioactive wastes. The determining property is that the repository can be housed in the stable bedrock at levels where the ground water has no contact with the biosphere and disposal and sealing can take place without disturbing the ground water stratification outside the disposal area. An advantage compared to a shallow repository of KBS-3 type, that is now being planned in Sweden, is that a borehole repository is likely to be technologically more robust, since the concept 'deep boreholes' seems to admit such a deep disposal that the entire disposal area would be surrounded by stable density-layered ground water, while a KBS-3 repository would be surrounded by moving ground water in contact with level close to the surface. This hydrological difference is of great importance for the safety in scenarios with leaching of radioactive substances. A deep repository is also less vulnerable for effects from natural events such as glaciation and earthquakes as well as from technological mishaps and terrorist actions. A crucial factor is, however, that the radioactive waste can be disposed of, in a secure way, at the intended depth, which will require new research and technology development.

  19. Cell Motility

    CERN Document Server

    Lenz, Peter

    2008-01-01

    Cell motility is a fascinating example of cell behavior which is fundamentally important to a number of biological and pathological processes. It is based on a complex self-organized mechano-chemical machine consisting of cytoskeletal filaments and molecular motors. In general, the cytoskeleton is responsible for the movement of the entire cell and for movements within the cell. The main challenge in the field of cell motility is to develop a complete physical description on how and why cells move. For this purpose new ways of modeling the properties of biological cells have to be found. This long term goal can only be achieved if new experimental techniques are developed to extract physical information from these living systems and if theoretical models are found which bridge the gap between molecular and mesoscopic length scales. Cell Motility gives an authoritative overview of the fundamental biological facts, theoretical models, and current experimental developments in this fascinating area.

  20. Photovoltaic Cells

    Directory of Open Access Journals (Sweden)

    Karolis Kiela

    2012-04-01

    Full Text Available The article deals with an overview of photovoltaic cells that are currently manufactured and those being developed, including one or several p-n junction, organic and dye-sensitized cells using quantum dots. The paper describes the advantages and disadvantages of various photovoltaic cells, identifies the main parameters, explains the main reasons for the losses that may occur in photovoltaic cells and looks at the ways to minimize them.Article in Lithuanian

  1. Electrochemical Cell

    DEFF Research Database (Denmark)

    1999-01-01

    The invention relates to a rechargeable electrochemical cell comprising a negative electrode, an electrolyte and a positive electrode in which the positive electrode structure comprises a lithium cobalt manganese oxide of the composition Li¿2?Co¿y?Mn¿2-y?O¿4? where 0 ... for capacity losses in lithium ion cells and lithium-alloy cells....

  2. Types of Stem Cells

    Science.gov (United States)

    ... PDF) Download an introduction to stem cells and stem cell research. Stem Cell Glossary Stem cell terms to know. ... stem cells blog from the International Society for Stem Cell Research. Learn About Stem Cells From Lab to You ...

  3. Cell suicide

    International Nuclear Information System (INIS)

    May, E.; Coffigny, H.

    2000-01-01

    In the fight of the cell against the damages caused to its DNA by genotoxic agents and specially by ionizing radiations, the p53 protein plays a central part. It intervenes in the proliferation control and the differentiation but also in the keeping of genome integrity. It can direct the damages cells toward suicide, or apoptosis, to avoid the risk of tumor appearance that would be fatal to the whole organism. That is by the disordered state of cells suicide programs that the tumor cells are going to develop. The knowledge of apoptosis mechanisms, to eventually start them on demand, rises up broad hopes in the cancer therapy. (N.C.)

  4. Bauxite formation on Tertiary sediments and Proterozoic bedrock in Suriname

    NARCIS (Netherlands)

    Monsels, D.A.

    2018-01-01

    The lateritic bauxite deposits in Suriname are traditionally distinguished into Coastal plain bauxites and Plateau bauxites, a subdivision that is primarily based on their topographic and geographic position. The first group is located in the lowlands of the coastal plain, while the second group is

  5. OSL-thermochronometry using bedrock quartz: a note of caution

    DEFF Research Database (Denmark)

    Guralnik, B.; Ankjærgaard, Christina; Jain, Mayank

    2015-01-01

    Optically stimulated luminescence (OSL) thermochronometry is an emerging application, whose capability to record sub-Million-year thermal histories is of increasing interest to a growing number of subdisciplines of Quaternary research. However, several recent studies have encountered difficulties...

  6. SRS BEDROCK PROBABILISTIC SEISMIC HAZARD ANALYSIS (PSHA) DESIGN BASIS JUSTIFICATION

    International Nuclear Information System (INIS)

    2005-01-01

    This represents an assessment of the available Savannah River Site (SRS) hard-rock probabilistic seismic hazard assessments (PSHAs), including PSHAs recently completed, for incorporation in the SRS seismic hazard update. The prior assessment of the SRS seismic design basis (WSRC, 1997) incorporated the results from two PSHAs that were published in 1988 and 1993. Because of the vintage of these studies, an assessment is necessary to establish the value of these PSHAs considering more recently collected data affecting seismic hazards and the availability of more recent PSHAs. This task is consistent with the Department of Energy (DOE) order, DOE O 420.1B and DOE guidance document DOE G 420.1-2. Following DOE guidance, the National Map Hazard was reviewed and incorporated in this assessment. In addition to the National Map hazard, alternative ground motion attenuation models (GMAMs) are used with the National Map source model to produce alternate hazard assessments for the SRS. These hazard assessments are the basis for the updated hard-rock hazard recommendation made in this report. The development and comparison of hazard based on the National Map models and PSHAs completed using alternate GMAMs provides increased confidence in this hazard recommendation. The alternate GMAMs are the EPRI (2004), USGS (2002) and a regional specific model (Silva et al., 2004). Weights of 0.6, 0.3 and 0.1 are recommended for EPRI (2004), USGS (2002) and Silva et al. (2004) respectively. This weighting gives cluster weights of .39, .29, .15, .17 for the 1-corner, 2-corner, hybrid, and Greens-function models, respectively. This assessment is judged to be conservative as compared to WSRC (1997) and incorporates the range of prevailing expert opinion pertinent to the development of seismic hazard at the SRS. The corresponding SRS hard-rock uniform hazard spectra are greater than the design spectra developed in WSRC (1997) that were based on the LLNL (1993) and EPRI (1988) PSHAs. The primary reasons for this difference is the greater activity rate used in contemporary models for the Charleston source zone and proper incorporation of uncertainty and randomness in GMAMs

  7. Radar sounding of bedrock and water table at Chalk River

    International Nuclear Information System (INIS)

    Annan, A.P.; Davis, J.L.

    1979-01-01

    When a spill of radioactive waste occurs, one of the main concerns is the flow pattern of ground water in the area of the spill. Ground probing radar is a relatively new geophysical technique which can provide high resolution data on the surficial geology and water distribution. The results of some preliminary radar experiments conducted at Chalk River Nuclear Laboratories (CRNL) of the Atomic Energy of Canada Limited (AECL), Chalk River, Ontario are presented. (auth)

  8. Significant differences in late Quaternary bedrock erosion and transport

    DEFF Research Database (Denmark)

    Andrews, John; Bjørk, Anders Anker; Eberl, Dennis

    2015-01-01

    in 10 cores from the two margins. On the East Greenland Shelf (EGS), late Quaternary samples have an average quartz weight per cent of 6.22.3 versus 12.83.9 from the West Greenland Shelf (WGS), and 12.024.8 versus 1.9 2.3wt% for pyroxene. K-means clustering indicated only 9% of the samples did not fit...

  9. Bedrock gorges in the central mainland Kachchh: Implications for ...

    Indian Academy of Sciences (India)

    movements have been mapped on two scattered and eroded hillocks located north of the gorge (fig- ure 2a). Though the channel of Khari river remains dry for most of the year, the gorge-reach is perma- nently filled with stagnant subsurface water that seeps up along the various structural features men- tioned above. This is ...

  10. 108 AFRICAN ARTS AS BEDROCK OF AFRICAN PHILOSOPHY Ol ...

    African Journals Online (AJOL)

    Tracie1

    the Лedrock of African Philosophy is African. Arts/Aesthetics. Aesthetics for Simon BlackЛurn (2005: 8) is “the study of feelings concepts and Уudgments arising from our appreciation of the arts or of oЛУects considered moving or Лeautiful or suЛlime.” Some of the questions art works raise are: can art work Лe vehicle of truth ...

  11. Bedrock gorges in the central mainland Kachchh: Implications for ...

    Indian Academy of Sciences (India)

    Author Affiliations. M G Thakkar1 B Goyal1 A K Patidar2 D M Maurya2 L S Chamyal2. Department of Geology, R R Lalan College, Bhuj, Kachchh 370 001, India. Department of Geology, The Maharaja Sayajirao University of Baroda, Vadodara 390 002, India.

  12. African arts as bedrock of African philosophy | Adesuyi | UJAH ...

    African Journals Online (AJOL)

    UJAH: Unizik Journal of Arts and Humanities. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 16, No 1 (2015) >. Log in or Register to get access to full text downloads.

  13. 108 AFRICAN ARTS AS BEDROCK OF AFRICAN PHILOSOPHY Ol ...

    African Journals Online (AJOL)

    Tracie1

    КЧН КОЬЭСОЭТМЬ аСТМС КЫО ЩСТХШЬШЩСТМКХ. Keywords: Ontological deЛate; African Arts; African. Philosophers. Introduction. The existence of African Philosophy has Лeen variously criticized and denied. It is not as if scholars have not responded to the criticisms. It has however not Лeen adequately responded ...

  14. Microstructure, porosity and mineralogy around fractures in Olkiluoto bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Kuva, J. (ed.); Myllys, M.; Timonen, J. [Jyvaeskylae Univ. (Finland); Kelokaski, M.; Ikonen, J.; Siitari-Kauppi, M. [Helsinki Univ. (Finland); Lindberg, A. [Geological Survey of Finland, Espoo (Finland); Aaltonen, I.

    2012-01-15

    3D distributions of minerals and porosities were determined for samples that included waterconducting fractures. The analysis of these samples was performed using conventional petrography methods, electron microscopy, C-14-PMMA porosity analysis and X-ray tomography. While X-ray tomography proved to be a very useful method when determining the inner structure of the samples, combining tomography results with those obtained by other methods turned out to be difficult without very careful sample preparation design. It seems that the properties of rock around a water-conducting fracture depend on so many uncorrelated factors that no clear pattern emerged even for rock samples with a given type of fracture. We can conclude, however, that a combination of different analysis methods can be useful and used to infer novel structural information about alteration zones adjacent to fracture surfaces. (orig.)

  15. DNAPL Dissolution in Bedrock Fractures And Fracture Networks

    Science.gov (United States)

    2011-06-01

    quarterly reports). Immediately following sparging, the bottles were placed in an anaerobic gas chamber where sodium-(L)-lactate, yeast extract and...chlorinated ethenes typically involves the subsurface delivery of mixed anaerobic cultures that contain Dehalococcoides spp. (DHC) that can...of the individual DHC strains in dehalorespiration of these compounds, and the identity of lactate fermenting strains in the culture, have not been

  16. Glacial flutings in bedrock, an observation in East Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby

    1978-01-01

    and 5 m in height and occur between 50 and 250 m above sea level inthe gently sloping lowland area adjacent to the fjord. They were probably formed beneath the lateral part of the former Harefjord-Glacier which receded rapidly in the fjord and exposed the area at c. 7500 years BP. Large scale glacial...... flutings have not been recorded before in Greenland, but seem to be of common occurrence in parts of North America. They have probably been formed near the margin of actively moving glaciers, and secondary flow in the basal ice may have played an important role...

  17. Values: The Bedrock of the Military Profession. A Selective Bibliography

    Science.gov (United States)

    1986-06-01

    conflicts of allegiance to his mission and his soldiers, and a psychological thriller that introspectively examines the effects of shouldering the...STUDY OF PSYCHOLOGICAL FACTORS IN WAR. Foreword by Sir Peter Hunt. New York, NY: Crane Russak, 1978. 189 p. U 22.3 .R5. Major General Richardson...British Army, retired), relates his personal experiences of the psychological problems facing the fighting soldier. Stouffer, Samuel A., et al. THE AMERICAN

  18. An evaluation of the bedrock aquifer system in northeastern Wisconsin

    Science.gov (United States)

    Emmons, P.J.

    1987-01-01

    Ground water is a major source of water in northeastern Wisconsin. The lower Fox River valley, located between Lake Winnebago and Green Bay in northeastern Wisconsin, is the second largest population center in Wisconsin. By 1957, ground-water withdrawals had lowered the potentiometric surface of the aquifer system as much as 440 feet below prepumping levels. With the exception of the city of Green Bay, which converted from ground water to surface water (Lake Michigan) for their municipal water supply in 1957, ground-water withdrawals have continually increased.

  19. Evaluation of percolation rate of bedrock aquifer in coastal area

    International Nuclear Information System (INIS)

    Lee, Jeong Hwan; Jung, Hae Ryong; Park, Joo Wan; Yoon, Jeong Hyoun; Cheong, Jae Yeol; Park, Sun Ju; Jun, Seong Chun

    2016-01-01

    Estimation of groundwater hydrologic cycle pattern is one of the most critical issues in sustainable management of groundwater resources in coastal area. This study estimated groundwater percolation by using the water balance methodology and hydrogeological characteristics of land use and soil. Evapotranspiration was computed by using the Thornthwaite method, and surface runoff was determined by using the SCS-CN technique. Groundwater storage change was obtained as 229 mm/a (17.8% of the average annual rainfall, 1286 mm/a), with 693 mm/a (60.1%) of evapotranspiration and 124 mm/a (9.6%) of surface runoff. Rainfall and groundwater storage change was highly correlated, comparing with the relationships between rainfall and evapotranspiration, and between rainfall and surface runoff. This result indicates that groundwater storage change responds more sensitively to precipitation than evapotranspiration and surface runoff

  20. An analytical model for hydraulic fracturing in shallow bedrock formations.

    Science.gov (United States)

    dos Santos, José Sérgio; Ballestero, Thomas Paul; Pitombeira, Ernesto da Silva

    2011-01-01

    A theoretical method is proposed to estimate post-fracturing fracture size and transmissivity, and as a test of the methodology, data collected from two wells were used for verification. This method can be employed before hydrofracturing in order to obtain estimates of the potential hydraulic benefits of hydraulic fracturing. Five different pumping test analysis methods were used to evaluate the well hydraulic data. The most effective methods were the Papadopulos-Cooper model (1967), which includes wellbore storage effects, and the Gringarten-Ramey model (1974), known as the single horizontal fracture model. The hydraulic parameters resulting from fitting these models to the field data revealed that as a result of hydraulic fracturing, the transmissivity increased more than 46 times in one well and increased 285 times in the other well. The model developed by dos Santos (2008), which considers horizontal radial fracture propagation from the hydraulically fractured well, was used to estimate potential fracture geometry after hydrofracturing. For the two studied wells, their fractures could have propagated to distances of almost 175 m or more and developed maximum apertures of about 2.20 mm and hydraulic apertures close to 0.30 mm. Fracturing at this site appears to have expanded and propagated existing fractures and not created new fractures. Hydraulic apertures calculated from pumping test analyses closely matched the results obtained from the hydraulic fracturing model. As a result of this model, post-fracturing geometry and resulting post-fracturing well yield can be estimated before the actual hydrofracturing. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

  1. Fuel Cells

    DEFF Research Database (Denmark)

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Fuel cells have been the subject of intense research and development efforts for the past decades. Even so, the technology has not had its commercial breakthrough yet. This entry gives an overview of the technological challenges and status of fuel cells and discusses the most promising applications...

  2. Fuel Cells

    Science.gov (United States)

    Hawkins, M. D.

    1973-01-01

    Discusses the theories, construction, operation, types, and advantages of fuel cells developed by the American space programs. Indicates that the cell is an ideal small-scale power source characterized by its compactness, high efficiency, reliability, and freedom from polluting fumes. (CC)

  3. Stem Cells

    DEFF Research Database (Denmark)

    Sommerlund, Julie

    2004-01-01

    '. This paper is about tech-noscience, and about the proliferation of connections and interdependencies created by it.More specifically, the paper is about stem cells. Biotechnology in general has the power to capture the imagination. Within the field of biotechnology nothing seems more provocative...... and tantalizing than stem cells, in research, in medicine, or as products....

  4. Solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, Moriaki; Hayashibara, Mitsuo

    1988-08-18

    Concerning the exsisting solar cell utilizing wavelength transition, the area of the solar cell element necessary for unit electric power output can be made small, but transition efficiency of the solar cell as a whole including a plastic plate with phosphor is not high. This invention concerns a solar cell which is appropriate for transferring the light within a wide spectrum range of the sunlight to electricilty efficiently, utilizes wavelength transition and has high efficiency per unit area. In other words, the solar cell of this invention has the feature of providing in parallel with a photoelectric transfer layer a layer of wavelength transitioning material (phosphor) which absorbs the light within the range of wavelength of low photoelectric transfer efficiency at the photoelectric transfer layer and emits the light within the range of wavelength in which the photoelectric transfer rate is high on the light incident side of the photoelectric transfer layer. (5 figs)

  5. Os manuais escolares, mídia de massa e suporte de representações sociais: o exemplo da Guerra Fria nos manuais franceses de História Textbooks: mass media and bedrock for social representations: The example of Cold War in the French history textbooks

    Directory of Open Access Journals (Sweden)

    Brigitte Morand

    2012-12-01

    Full Text Available O manual escolar se constitui em um objeto cultural complexo e é, de fato, um significativo suporte de representações sociais. Sua elaboração se dá no cruzamento de lógicas institucionais, científicas, didáticas e editoriais. Este artigo tem como tema central as representações da Guerra Fria nos manuais escolares franceses de história e geografia, utilizados no ensino secundário entre os anos de 1959 a 2006, e foi desenvolvido a partir de um método que mescla abordagens quantitativas e qualitativas. Em nosso estudo, pudemos constatar que os manuais são cada vez mais ilustrados, e as imagens, assim como o texto que estrutura a lição, propõem uma narrativa articulada em torno da noção central de "partilha do mundo", na qual se encarnam os personagens, os acontecimentos, mas também as noções e os conceitos históricos. Essas imagens, fartamente divulgadas, funcionam igualmente em rede, uma vez que, na imprensa escrita quotidiana, veiculam muito mais uma memória coletiva do que um saber histórico.A textbook is a complex object at crossroad of different approaches, institutional, scientific, didactical, editorial, which all take part in its conception. In fact, the texbook is genuine bedrock for social representations that can be scrutinized using quantitative and qualitative methods. This paper analyses the representations of the Cold war in French history and geography textbooks for secondary education, published from 1959 to 2006. We show that textbooks are more and more illustrated through years. The pictures, as well as the texts of the lesson, provide a narrative based on the central notion of "the division of the World" embodies in characters, events and historical concepts as well. These pictures act as a network, exactly as they do in the daily press, and therefore they convey a collective memory rather than a historical knowledge.

  6. Bi-Cell Unit for Fuel Cell.

    Science.gov (United States)

    The patent concerns a bi-cell unit for a fuel cell . The bi-cell unit is comprised of two electrode packs. Each of the electrode packs includes an...invention relates in general to a bi-cell unit for a fuel cell and in particular, to a bi-cell unit for a hydrazine-air fuel cell .

  7. Dry cell battery poisoning

    Science.gov (United States)

    Batteries - dry cell ... Acidic dry cell batteries contain: Manganese dioxide Ammonium chloride Alkaline dry cell batteries contain: Sodium hydroxide Potassium hydroxide Lithium dioxide dry cell batteries ...

  8. Electrochemical cell

    Science.gov (United States)

    Redey, L.I.; Myles, K.M.; Vissers, D.R.; Prakash, J.

    1996-07-02

    An electrochemical cell is described with a positive electrode having an electrochemically active layer of at least one transition metal chloride. A negative electrode of an alkali metal and a compatible electrolyte including an alkali metal salt molten at cell operating temperature is included in the cell. The electrolyte is present at least partially as a corrugated {beta}{double_prime} alumina tube surrounding the negative electrode interior to the positive electrode. The ratio of the volume of liquid electrolyte to the volume of the positive electrode is in the range of from about 0.1 to about 3. A plurality of stacked electrochemical cells is disclosed each having a positive electrode, a negative electrode of an alkali metal molten at cell operating temperature, and a compatible electrolyte. The electrolyte is at least partially present as a corrugated {beta}{double_prime} alumina sheet separating the negative electrode and interior to the positive electrodes. The alkali metal is retained in a porous electrically conductive ceramic, and seals for sealing the junctures of the electrolyte and the adjacent electrodes at the peripheries thereof. 8 figs.

  9. Electrochemical cell

    Science.gov (United States)

    Kaun, T.D.

    An improved secondary electrochemical cell is disclosed having a negative electrode of lithium aluminum, a positive electrode of iron sulfide, a molten electrolyte of lithium chloride and potassium chloride, and the combination that the fully charged theoretical capacity of the negative electrode is in the range of 0.5 to 1.0 that of the positive electrode. The cell thus is negative electrode limiting during discharge cycling. Preferably, the negative electrode contains therein, in the approximate range of 1 to 10 volume % of the electrode, an additive from the materials of graphitized carbon, aluminum-iron alloy, and/or magnesium oxide.

  10. Solar cells

    International Nuclear Information System (INIS)

    1980-01-01

    A method of producing solar cells is described which consists of producing a substantially monocrystalline tubular body of silicon or other suitable semiconductor material, treating this body to form an annular rectifying junction and then cutting it longitudinally to form a number of nearly flat ribbons from which the solar cells are fabricated. The P=N rectifying junction produced by the formation of silicon dioxide on the layers at the inner and outer surfaces of the body can be formed by ion-implantation or diffusion. (U.K.)

  11. Tuning Collective Cell Migration by Cell-Cell Junction Regulation

    NARCIS (Netherlands)

    Friedl, P.; Mayor, R.

    2017-01-01

    Collective cell migration critically depends on cell-cell interactions coupled to a dynamic actin cytoskeleton. Important cell-cell adhesion receptor systems implicated in controlling collective movements include cadherins, immunoglobulin superfamily members (L1CAM, NCAM, ALCAM), Ephrin/Eph

  12. Energy storage cells

    Energy Technology Data Exchange (ETDEWEB)

    Gulia, N.V.

    1980-01-01

    The book deals with the characteristics and potentialities of energy storage cells of various types. Attention is given to electrical energy storage cells (electrochemical, electrostatic, and electrodynamic cells), mechanical energy storage cells (mechanical flywheel storage cells), and hybrid storage systems.

  13. Squamous Cell Carcinoma

    Science.gov (United States)

    ... Kids’ zone Video library Find a dermatologist Squamous cell carcinoma Overview Squamous cell carcinoma: This man's skin ... a squamous cell carcinoma on his face. Squamous cell carcinoma: Overview Squamous cell carcinoma (SCC) is a ...

  14. Learn About Stem Cells

    Science.gov (United States)

    ... PDF) Download an introduction to stem cells and stem cell research. Stem Cell Glossary Stem cell terms to know. ... ISSCR Get Involved Media © 2015 International Society for Stem Cell Research Terms of Use Disclaimer Privacy Policy

  15. Electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.H.; Kubala, D.M.; Bennett, R.J.

    1977-01-13

    The high energy densities of primary cells on the basis of lithium or sodium as anode material, liquid cathode materials and nonaqueous electrolytes could not previously be fully utilised, because volume changes appearing during the discharge process inside the cell lead to an increase of cell impedance. In order to overcome this disadvantage, according to the invention a tube consisting of carbon which is slotted in the longitudinal direction is used as the cathode current collector. It is elastic in the radial direction and exerts an even pressure in the beaker-shaped cell vessel on the separator and therefore on the anode material touching the inner wall of the vessel. In order to achieve the elastic deformability of the cathode current collector, acetylene soot is used, to which are added as described in the invention, elastomers and/or mixed polymers in quantities of 10 to 30% by weight. Further claims concern the use of at least one oxyhalide of an element of groups V or VI or a halide of an element of groups IV, V or VI of the periodic table in the cathode solution.

  16. Potent Cells

    Science.gov (United States)

    Liu, Dennis

    2007-01-01

    It seems hard to believe that Dolly the cloned sheep was born 10 years ago, kindling furious arguments over the prospects and ethics of cloning a human. Today, the controversy over cloning is entwined, often confused, with concerns over the use of human embryonic stem cells. Most people are unclear what cloning is, and they know even less when it…

  17. Fuel cells:

    DEFF Research Database (Denmark)

    Sørensen, Bent

    2013-01-01

    A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil...... and nuclear fuel-based energy technologies....

  18. Stem Cells

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 3. Stem Cells: A Dormant Volcano Within Our Body? Devaveena Dey Annapoorni Rangarajan. General Article Volume 12 Issue 3 March 2007 pp 27-34. Fulltext. Click here to view fulltext PDF. Permanent link:

  19. Photovoltaic cell

    Science.gov (United States)

    Gordon, Roy G.; Kurtz, Sarah

    1984-11-27

    In a photovoltaic cell structure containing a visibly transparent, electrically conductive first layer of metal oxide, and a light-absorbing semiconductive photovoltaic second layer, the improvement comprising a thin layer of transition metal nitride, carbide or boride interposed between said first and second layers.

  20. Fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, Hirofumi.

    1989-05-22

    This invention aims to maintain a long-term operation with stable cell output characteristics by uniformly supplying an electrolyte from the reserver to the matrix layer over the entire matrix layer, and further to prevent the excessive wetting of the catalyst layer by smoothly absorbing the volume change of the electrolyte, caused by the repeated stop/start-up of the fuel cell, within the reserver system. For this purpose, in this invention, an electrolyte transport layer, which connects with an electrolyte reservor formed at the electrode end, is partly formed between the electrode material and the catalyst layer; a catalyst layer, which faces the electrolyte transport layer, has through-holes, which connect to the matrix, dispersely distributed. The electrolyte-transport layer is a thin sheet of a hydrophilic fibers which are non-wovens of such fibers as carbon, silicon carbide, silicon nitride or inorganic oxides. 11 figs.

  1. Tuning Collective Cell Migration by Cell-Cell Junction Regulation.

    Science.gov (United States)

    Friedl, Peter; Mayor, Roberto

    2017-04-03

    Collective cell migration critically depends on cell-cell interactions coupled to a dynamic actin cytoskeleton. Important cell-cell adhesion receptor systems implicated in controlling collective movements include cadherins, immunoglobulin superfamily members (L1CAM, NCAM, ALCAM), Ephrin/Eph receptors, Slit/Robo, connexins and integrins, and an adaptive array of intracellular adapter and signaling proteins. Depending on molecular composition and signaling context, cell-cell junctions adapt their shape and stability, and this gradual junction plasticity enables different types of collective cell movements such as epithelial sheet and cluster migration, branching morphogenesis and sprouting, collective network migration, as well as coordinated individual-cell migration and streaming. Thereby, plasticity of cell-cell junction composition and turnover defines the type of collective movements in epithelial, mesenchymal, neuronal, and immune cells, and defines migration coordination, anchorage, and cell dissociation. We here review cell-cell adhesion systems and their functions in different types of collective cell migration as key regulators of collective plasticity. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  2. Electrorefining cell evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Bronson, M.C.; Thomas, R.L. (ed.)

    1989-04-14

    Operational characteristics of the LANL electrorefining cell, a modified LANL electrorefining cell, and an advanced electrorefining cell (known as the CRAC cell) were determined. Average process yields achieved were: 75% for the LANL cell, 82% for the modified LANL cell, and 86% for the CRAC cell. All product metal from the LANL and modified LANL cells was within foundry specifications. Metal from one run in the CRAC cell exceeded foundry specifications for tantalum. The LANL and modified LANL cells were simple in design and operation, but product separation was more labor intensive than with the CRAC cell. The CRAC cell was more complicated in design but remained relatively simple in operation. A decision analysis concluded that the modified LANL cell was the preferred cell. It was recommended that the modified LANL cell be implemented by the Plutonium Recovery Project at Rocky Flats and that development of the CRAC cell continue. 8 refs., 22 figs., 12 tabs.

  3. Basal Cell Carcinoma

    Science.gov (United States)

    ... Kids’ zone Video library Find a dermatologist Basal cell carcinoma Overview Basal cell carcinoma: This skin cancer ... that has received years of sun exposure. Basal cell carcinoma: Overview Basal cell carcinoma (BCC) is the ...

  4. Stem Cell Basics

    Science.gov (United States)

    ... healthy cells replace damaged cells in adult organisms. Stem cell research is one of the most fascinating areas of ... as with many expanding fields of scientific inquiry, research on stem cells raises scientific questions as rapidly as it generates ...

  5. Sickle cell anemia

    Science.gov (United States)

    Anemia - sickle cell; Hemoglobin SS disease (Hb SS); Sickle cell disease ... Sickle cell anemia is caused by an abnormal type of hemoglobin called hemoglobin S. Hemoglobin is a protein inside red blood cells ...

  6. DNA-cell conjugates

    Science.gov (United States)

    Hsiao, Shih-Chia; Francis, Matthew B.; Bertozzi, Carolyn; Mathies, Richard; Chandra, Ravi; Douglas, Erik; Twite, Amy; Toriello, Nicholas; Onoe, Hiroaki

    2016-05-03

    The present invention provides conjugates of DNA and cells by linking the DNA to a native functional group on the cell surface. The cells can be without cell walls or can have cell walls. The modified cells can be linked to a substrate surface and used in assay or bioreactors.

  7. Potency of Stem Cells

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Potency of Stem Cells. Totipotent Stem Cells (Zygote + first 2 divisions). -Can form placenta, embryo, and any cell of the body. Pluripotent (Embryonic Stem Cells). -Can form any cell of the body but can not form placenta, hence no embryo. Multipotent (Adult stem cells).

  8. Skin Stem Cells in Skin Cell Therapy

    Directory of Open Access Journals (Sweden)

    Mollapour Sisakht

    2015-12-01

    Full Text Available Context Preclinical and clinical research has shown that stem cell therapy is a promising therapeutic option for many diseases. This article describes skin stem cells sources and their therapeutic applications. Evidence Acquisition Compared with conventional methods, cell therapy reduces the surgical burden for patients because it is simple and less time-consuming. Skin cell therapy has been developed for variety of diseases. By isolation of the skin stem cell from the niche, in vitro expansion and transplantation of cells offers a surprising healing capacity profile. Results Stem cells located in skin cells have shown interesting properties such as plasticity, transdifferentiation, and specificity. Mesenchymal cells of the dermis, hypodermis, and other sources are currently being investigated to promote regeneration. Conclusions Because skin stem cells are highly accessible from autologous sources and their immunological profile is unique, they are ideal for therapeutic approaches. Optimization of administrative routes requires more investigation own to the lack of a standard protocol.

  9. NKT Cell Responses to B Cell Lymphoma.

    Science.gov (United States)

    Li, Junxin; Sun, Wenji; Subrahmanyam, Priyanka B; Page, Carly; Younger, Kenisha M; Tiper, Irina V; Frieman, Matthew; Kimball, Amy S; Webb, Tonya J

    2014-06-01

    Natural killer T (NKT) cells are a unique subset of CD1d-restricted T lymphocytes that express characteristics of both T cells and natural killer cells. NKT cells mediate tumor immune-surveillance; however, NKT cells are numerically reduced and functionally impaired in lymphoma patients. Many hematologic malignancies express CD1d molecules and co-stimulatory proteins needed to induce anti-tumor immunity by NKT cells, yet most tumors are poorly immunogenic. In this study, we sought to investigate NKT cell responses to B cell lymphoma. In the presence of exogenous antigen, both mouse and human NKT cell lines produce cytokines following stimulation by B cell lymphoma lines. NKT cell populations were examined ex vivo in mouse models of spontaneous B cell lymphoma, and it was found that during early stages, NKT cell responses were enhanced in lymphoma-bearing animals compared to disease-free animals. In contrast, in lymphoma-bearing animals with splenomegaly and lymphadenopathy, NKT cells were functionally impaired. In a mouse model of blastoid variant mantle cell lymphoma, treatment of tumor-bearing mice with a potent NKT cell agonist, α-galactosylceramide (α-GalCer), resulted in a significant decrease in disease pathology. Ex vivo studies demonstrated that NKT cells from α-GalCer treated mice produced IFN-γ following α-GalCer restimulation, unlike NKT cells from vehicle-control treated mice. These data demonstrate an important role for NKT cells in the immune response to an aggressive hematologic malignancy like mantle cell lymphoma.

  10. Epithelial cell polarity, stem cells and cancer

    DEFF Research Database (Denmark)

    Martin-Belmonte, Fernando; Perez-Moreno, Mirna

    2011-01-01

    After years of extensive scientific discovery much has been learned about the networks that regulate epithelial homeostasis. Loss of expression or functional activity of cell adhesion and cell polarity proteins (including the PAR, crumbs (CRB) and scribble (SCRIB) complexes) is intricately related......, deregulation of adhesion and polarity proteins can cause misoriented cell divisions and increased self-renewal of adult epithelial stem cells. In this Review, we highlight some advances in the understanding of how loss of epithelial cell polarity contributes to tumorigenesis....

  11. Modeling cell-in-cell structure into its biological significance

    OpenAIRE

    He, M-f; Wang, S; Wang, Y; Wang, X-n

    2013-01-01

    Although cell-in-cell structure was noted 100 years ago, the molecular mechanisms of ?entering' and the destination of cell-in-cell remain largely unclear. It takes place among the same type of cells (homotypic cell-in-cell) or different types of cells (heterotypic cell-in-cell). Cell-in-cell formation affects both effector cells and their host cells in multiple aspects, while cell-in-cell death is under more intensive investigation. Given that cell-in-cell has an important role in maintainin...

  12. Sickle Cell Disease

    Science.gov (United States)

    Sickle cell anemia is a disease in which your body produces abnormally shaped red blood cells. The cells are shaped like a crescent or sickle. They ... last as long as normal, round red blood cells. This leads to anemia. The sickle cells also ...

  13. Host cell reactivation in mammalian cells

    International Nuclear Information System (INIS)

    Lytle, C.D.; Benane, S.G.; Stafford, J.E.

    1976-01-01

    The survival of UV-irradiated herpes simplex virus was determined in cultured Potoroo (a marsupial) and human cells under lighting conditions which promoted photereactivation. Photoreactivation was readily demonstrated for herpes virus in two lines of Potoroo cells with dose reduction factors of 0.7 to 0.8 for ovary cells and 0.5 to 0.7 for kidney cells. Light from Blacklite (near UV) lamps was more effective than from Daylight (mostly visible) lamps, suggesting that near UV radiation was more effecient for photoreactivation in Potoroo cells. The quantitative and qualitative aspects of this photoreactivation were similar to those reported for a similar virus infecting chick embryo cells. UV-survival curves of herpes virus in Potoroo cells indicated a high level of 'dark' host cell reactivation. No photoreactivation was found for UV-irradiated vaccinia virus in Potoroo cells. A similar photoreactivation study was done using special control lighting (lambda>600 nm) and human cells with normal repair and with cells deficient in excision repair (XP). No photoreactivation was found for UV-irradiated herpes virus in either human cell with either Blacklite or Daylight lamps as the sources of photoreactivating light. This result contrasts with a report of photoreactivation for a herpes virus in the same XP cells using incandescent lamps. (author)

  14. Fuel cell-fuel cell hybrid system

    Science.gov (United States)

    Geisbrecht, Rodney A.; Williams, Mark C.

    2003-09-23

    A device for converting chemical energy to electricity is provided, the device comprising a high temperature fuel cell with the ability for partially oxidizing and completely reforming fuel, and a low temperature fuel cell juxtaposed to said high temperature fuel cell so as to utilize remaining reformed fuel from the high temperature fuel cell. Also provided is a method for producing electricity comprising directing fuel to a first fuel cell, completely oxidizing a first portion of the fuel and partially oxidizing a second portion of the fuel, directing the second fuel portion to a second fuel cell, allowing the first fuel cell to utilize the first portion of the fuel to produce electricity; and allowing the second fuel cell to utilize the second portion of the fuel to produce electricity.

  15. Are mesenchymal stromal cells immune cells?

    NARCIS (Netherlands)

    M.J. Hoogduijn (Martin)

    2015-01-01

    textabstractMesenchymal stromal cells (MSCs) are considered to be promising agents for the treatment of immunological disease. Although originally identified as precursor cells for mesenchymal lineages, in vitro studies have demonstrated that MSCs possess diverse immune regulatory capacities.

  16. Galvanic cells: setting up the Daniell cell.

    OpenAIRE

    Milla González, Miguel

    2008-01-01

    With the reagents (0.05M copper nitrate solution, 0.05M zinc nitrate solution) and material (glassware, potentiometer, electric wire) availabe in the laboratory, the user must set up the Daniell cell. Different configurations can be possible if the half cells are filled with either electrolyte solution. The cell connections to the measuring device can also be changed. In all instances, an explanation of the set up cell is obtained as well as of the measured potential difference.

  17. Inside the Cell

    Science.gov (United States)

    ... NIGMS Home > Science Education > Inside the Cell Inside the Cell Seeing Cells Classroom Poster Order a Free Copy Spotlight The Cell’s Mailroom The Proteasome: The Cell’s Trash Processor in ...

  18. Stem Cell Information: Glossary

    Science.gov (United States)

    ... Long-term self-renewal Meiosis Mesenchymal stem cells Mesoderm Microenvironment Mitosis Multipotent Neural stem cell Neurons Oligodendrocyte ... layers. The three layers are the ectoderm , the mesoderm , and the endoderm . Hematopoietic stem cell - A stem ...

  19. Lung cancer - small cell

    Science.gov (United States)

    Cancer - lung - small cell; Small cell lung cancer; SCLC ... About 15% of all lung cancer cases are SCLC. Small cell lung cancer is slightly more common in men than women. Almost all cases of SCLC are ...

  20. [Natural killer cells complot with dendritic cells].

    Science.gov (United States)

    Bielawska-Pohl, Aleksandra; Pajtasz-Piasecka, Elżbieta; Duś, Danuta

    2013-03-18

    Dendritic cells (DC) were initially considered as antigen presenting cells participating in the polarization of the immune response. Further understanding of their biology allowed determining their additional functions such as immunoregulatory and cytotoxicity. Until recently natural killer (NK) cells were known as a homogeneous population of lymphocytes capable of non-specific recognizing and eliminating target cells. Now it is widely accepted that NK cells, as a heterogeneous population, may also possess immunomodulatory functions. Moreover, the most recent analysis of the interactions between DC and NK cells revealed the exceptional functions of these cells. As a result of these studies the existence of bitypic cell population was postulated. The distinguishing features of these hybrid cells are: the expression of surface receptors typical for NK cells and DC, the cytotoxic activity, the production of interferons as well as their ability to present antigen after prior stimulation. Despite the lack of strong direct evidence that the same cell can be both cytotoxic and effectively present the antigen at the same time, there are experimental findings suggesting that generated ex vivo bitypic cells may be used in antitumor therapy. 

  1. NK cells and T cells: mirror images?

    NARCIS (Netherlands)

    Versteeg, R.

    1992-01-01

    The expression of MHC class I molecules protects cells against lysis by natural killer (NK) cells. It is possible that NK cells are 'educated' to recognize self MHC class I molecules and that the combination of self peptide and MHC class I molecule blocks NK-mediated lysis. Here, Rogier Versteeg

  2. Snail modulates cell metabolism in MDCK cells

    Energy Technology Data Exchange (ETDEWEB)

    Haraguchi, Misako, E-mail: haraguci@m3.kufm.kagoshima-u.ac.jp [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Indo, Hiroko P. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Iwasaki, Yasumasa [Health Care Center, Kochi University, Kochi 780-8520 (Japan); Iwashita, Yoichiro [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Fukushige, Tomoko [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Majima, Hideyuki J. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Izumo, Kimiko; Horiuchi, Masahisa [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Kanekura, Takuro [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Furukawa, Tatsuhiko [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Ozawa, Masayuki [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)

    2013-03-22

    Highlights: ► MDCK/snail cells were more sensitive to glucose deprivation than MDCK/neo cells. ► MDCK/snail cells had decreased oxidative phosphorylation, O{sub 2} consumption and ATP content. ► TCA cycle enzyme activity, but not expression, was lower in MDCK/snail cells. ► MDCK/snail cells showed reduced PDH activity and increased PDK1 expression. ► MDCK/snail cells showed reduced expression of GLS2 and ACLY. -- Abstract: Snail, a repressor of E-cadherin gene transcription, induces epithelial-to-mesenchymal transition and is involved in tumor progression. Snail also mediates resistance to cell death induced by serum depletion. By contrast, we observed that snail-expressing MDCK (MDCK/snail) cells undergo cell death at a higher rate than control (MDCK/neo) cells in low-glucose medium. Therefore, we investigated whether snail expression influences cell metabolism in MDCK cells. Although gylcolysis was not affected in MDCK/snail cells, they did exhibit reduced pyruvate dehydrogenase (PDH) activity, which controls pyruvate entry into the tricarboxylic acid (TCA) cycle. Indeed, the activity of multiple enzymes involved in the TCA cycle was decreased in MDCK/snail cells, including that of mitochondrial NADP{sup +}-dependent isocitrate dehydrogenase (IDH2), succinate dehydrogenase (SDH), and electron transport Complex II and Complex IV. Consequently, lower ATP content, lower oxygen consumption and increased survival under hypoxic conditions was also observed in MDCK/snail cells compared to MDCK/neo cells. In addition, the expression and promoter activity of pyruvate dehydrogenase kinase 1 (PDK1), which phosphorylates and inhibits the activity of PDH, was increased in MDCK/snail cells, while expression levels of glutaminase 2 (GLS2) and ATP-citrate lyase (ACLY), which are involved in glutaminolysis and fatty acid synthesis, were decreased in MDCK/snail cells. These results suggest that snail modulates cell metabolism by altering the expression and activity of

  3. Cell control report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This extensive report provides an essential overview of cells and their use as factory automation building blocks. The following issues are discussed in depth: Cell integration Cell software and standards Future technologies applied to cells Plus Cell control applications including: - rotary parts manufacturing - diesel engine component development - general cell control development at the General Electric Corporation - a vendor list.

  4. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL)Established to investigate, integrate, testand verifyperformance and technology readiness offuel cell systems and fuel reformers for use with...

  5. Squamous cell skin cancer

    Science.gov (United States)

    ... that reflect light more, such as water, sand, concrete, and areas that are painted white. The higher ... - skin - squamous cell; Skin cancer - squamous cell; Nonmelanoma skin cancer - squamous ...

  6. The hallmarks of cell-cell fusion.

    Science.gov (United States)

    Hernández, Javier M; Podbilewicz, Benjamin

    2017-12-15

    Cell-cell fusion is essential for fertilization and organ development. Dedicated proteins known as fusogens are responsible for mediating membrane fusion. However, until recently, these proteins either remained unidentified or were poorly understood at the mechanistic level. Here, we review how fusogens surmount multiple energy barriers to mediate cell-cell fusion. We describe how early preparatory steps bring membranes to a distance of ∼10 nm, while fusogens act in the final approach between membranes. The mechanical force exerted by cell fusogens and the accompanying lipidic rearrangements constitute the hallmarks of cell-cell fusion. Finally, we discuss the relationship between viral and eukaryotic fusogens, highlight a classification scheme regrouping a superfamily of fusogens called Fusexins, and propose new questions and avenues of enquiry. © 2017. Published by The Company of Biologists Ltd.

  7. Cell mechanics: a dialogue

    Science.gov (United States)

    Tao, Jiaxiang; Li, Yizeng; Vig, Dhruv K.; Sun, Sean X.

    2017-03-01

    Under the microscope, eukaryotic animal cells can adopt a variety of different shapes and sizes. These cells also move and deform, and the physical mechanisms driving these movements and shape changes are important in fundamental cell biology, tissue mechanics, as well as disease biology. This article reviews some of the basic mechanical concepts in cells, emphasizing continuum mechanics description of cytoskeletal networks and hydrodynamic flows across the cell membrane. We discuss how cells can generate movement and shape changes by controlling mass fluxes at the cell boundary. These mass fluxes can come from polymerization/depolymerization of actin cytoskeleton, as well as osmotic and hydraulic pressure-driven flow of water across the cell membrane. By combining hydraulic pressure control with force balance conditions at the cell surface, we discuss a quantitative mechanism of cell shape and volume control. The broad consequences of this model on cell mechanosensation and tissue mechanics are outlined.

  8. [Exosomes and Immune Cells].

    Science.gov (United States)

    Seo, Naohiro

    2017-05-01

    In addition to the cytokines and cytotoxic granules, exosomes have been known as the intercellular communicator and cytotoxic missile of immune cells for the past decade. It has been well known that mature dendritic cell(DC)-derived exosomes participate in the T cell and natural killer(NK)cell activation, while immature DCs secrete tolerogenic exosomes for regulatory T(Treg)cell generation. Treg cell-derived EVs act as a suppressor against pathogenic type-1 T helper(Th1)cell responses. CD8+ T cells produce tumoricidal exosomes for preventing tumor invasion and metastasis transiently after T cell receptor(TCR)-mediated stimulation. Thus, immune cells produce functional exosomes in the activation state- and/or differentiation stage-dependent manner. In this review, the role of immune cell-derived exosomes will be introduced, focusing mainly on immune reaction against tumor.

  9. Tracking adult stem cells

    NARCIS (Netherlands)

    Snippert, H.J.G.; Clevers, H.

    2011-01-01

    The maintenance of stem-cell-driven tissue homeostasis requires a balance between the generation and loss of cell mass. Adult stem cells have a close relationship with the surrounding tissue--known as their niche--and thus, stem-cell studies should preferably be performed in a physiological context,

  10. Mesenchymal stem cell like (MSCl) cells generated from human embryonic stem cells support pluripotent cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Varga, Nora [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary); Vereb, Zoltan; Rajnavoelgyi, Eva [Department of Immunology, Medical and Health Science Centre, University of Debrecen, Debrecen (Hungary); Nemet, Katalin; Uher, Ferenc; Sarkadi, Balazs [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary); Apati, Agota, E-mail: apati@kkk.org.hu [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary)

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer MSC like cells were derived from hESC by a simple and reproducible method. Black-Right-Pointing-Pointer Differentiation and immunosuppressive features of MSCl cells were similar to bmMSC. Black-Right-Pointing-Pointer MSCl cells as feeder cells support the undifferentiated growth of hESC. -- Abstract: Mesenchymal stem cell like (MSCl) cells were generated from human embryonic stem cells (hESC) through embryoid body formation, and isolated by adherence to plastic surface. MSCl cell lines could be propagated without changes in morphological or functional characteristics for more than 15 passages. These cells, as well as their fluorescent protein expressing stable derivatives, efficiently supported the growth of undifferentiated human embryonic stem cells as feeder cells. The MSCl cells did not express the embryonic (Oct4, Nanog, ABCG2, PODXL, or SSEA4), or hematopoietic (CD34, CD45, CD14, CD133, HLA-DR) stem cell markers, while were positive for the characteristic cell surface markers of MSCs (CD44, CD73, CD90, CD105). MSCl cells could be differentiated toward osteogenic, chondrogenic or adipogenic directions and exhibited significant inhibition of mitogen-activated lymphocyte proliferation, and thus presented immunosuppressive features. We suggest that cultured MSCl cells can properly model human MSCs and be applied as efficient feeders in hESC cultures.

  11. Mammalian cell biology

    International Nuclear Information System (INIS)

    Elkind, M.M.

    1975-01-01

    Progress is reported on the following research projects: the effects of N-ethyl-maleimide and hydroxyurea on hamster cells in culture; sensitization of synchronized human cells to x rays by N-ethylmaleimide; sensitization of hypoxic mammalian cells with a sulfhydryl inhibitor; damage interaction due to ionizing and nonionizing radiation in mammalian cells; DNA damage relative to radioinduced cell killing; spurious photolability of DNA labeled with methyl- 14 C-thymidine; radioinduced malignant transformation of cultured mouse cells; a comparison of properties of uv and near uv light relative to cell function and DNA damage; Monte Carlo simulation of DNA damage and repair mechanisms; and radiobiology of fast neutrons

  12. Molten carbonate fuel cell

    Science.gov (United States)

    Kaun, T.D.; Smith, J.L.

    1986-07-08

    A molten electrolyte fuel cell is disclosed with an array of stacked cells and cell enclosures isolating each cell except for access to gas manifolds for the supply of fuel or oxidant gas or the removal of waste gas. The cell enclosures collectively provide an enclosure for the array and effectively avoid the problems of electrolyte migration and the previous need for compression of stack components. The fuel cell further includes an inner housing about and in cooperation with the array enclosure to provide a manifold system with isolated chambers for the supply and removal of gases. An external insulated housing about the inner housing provides thermal isolation to the cell components.

  13. Mesenchymal Stem Cells

    DEFF Research Database (Denmark)

    Horwood, Nicole J.; Dazzi, Francesco; Zaher, Walid

    2012-01-01

    Mesenchymal stem cells (MSC) are stem cell populations present among the bone marrow stroma and a number of other tissues that are capable of multi-lineage differentiation into mesoderm-type cells such as osteoblasts, adipocytes and chondrocytes. MSC provide supportive stroma for growth...... and differentiation of hematopoietic stem cells (HSC) and hematopoiesis. These cells have been described as important immunoregulators due to their ability to suppress T cells proliferation. MSC can also directly contribute to tissue repair by migrating to sites of injury and providing a source of cells...

  14. Removable hot cell liners

    International Nuclear Information System (INIS)

    Fitzgibbon, F.J.; Shaffer, D.S.; Ledbetter, J.M.; Wood, W.T.

    1978-01-01

    In 1959 the Los Alamos Scientific Laboratory (LASL) proposed design requirements for an alpha-gamma box system. Among the requirements was a provision for conveniently removing a contaminated cell liner (alpha-gamma box) from an operating cell. Various situations, such as a change in program direction, outmoded equipment, or an unexpected development, could result in a decision to replace a cell liner and reuse the cell for another purpose. The contaminated cell liners could either be stored temporarily for possible future use or disposed of at the LASL contaminated Waste Disposal Area. LASL's experience removing used hot cell liners from operating cells is described

  15. Cell-Based Therapy

    Directory of Open Access Journals (Sweden)

    Masaaki Kitada

    2012-01-01

    Full Text Available Cell transplantation is a strategy with great potential for the treatment of Parkinson's disease, and many types of stem cells, including neural stem cells and embryonic stem cells, are considered candidates for transplantation therapy. Mesenchymal stem cells are a great therapeutic cell source because they are easy accessible and can be expanded from patients or donor mesenchymal tissues without posing serious ethical and technical problems. They have trophic effects for protecting damaged tissues as well as differentiation ability to generate a broad spectrum of cells, including dopamine neurons, which contribute to the replenishment of lost cells in Parkinson's disease. This paper focuses mainly on the potential of mesenchymal stem cells as a therapeutic cell source and discusses their potential clinical application in Parkinson's disease.

  16. NK Cell Exhaustion

    Science.gov (United States)

    Bi, Jiacheng; Tian, Zhigang

    2017-01-01

    Natural killer cells are important effector lymphocytes of the innate immune system, playing critical roles in antitumor and anti-infection host defense. Tumor progression or chronic infections, however, usually leads to exhaustion of NK cells, thus limiting the antitumor/infection potential of NK cells. In many tumors or chronic infections, multiple mechanisms might contribute to the exhaustion of NK cells, such as dysregulated NK cell receptors signaling, as well as suppressive effects by regulatory cells or soluble factors within the microenvironment. Better understanding of the characteristics, as well as the underlying mechanisms of NK cell exhaustion, not only should increase our understanding of the basic biology of NK cells but also could reveal novel NK cell-based antitumor/infection targets. Here, we provide an overview of our current knowledge on NK cell exhaustion in tumors, and in chronic infections. PMID:28702032

  17. Fuel cells seminar

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    This year`s meeting highlights the fact that fuel cells for both stationary and transportation applications have reached the dawn of commercialization. Sales of stationary fuel cells have grown steadily over the past 2 years. Phosphoric acid fuel cell buses have been demonstrated in urban areas. Proton-exchange membrane fuel cells are on the verge of revolutionizing the transportation industry. These activities and many more are discussed during this seminar, which provides a forum for people from the international fuel cell community engaged in a wide spectrum of fuel cell activities. Discussions addressing R&D of fuel cell technologies, manufacturing and marketing of fuel cells, and experiences of fuel cell users took place through oral and poster presentations. For the first time, the seminar included commercial exhibits, further evidence that commercial fuel cell technology has arrived. A total of 205 papers is included in this volume.

  18. Cell fusion of bone marrow cells and somatic cell reprogramming by embryonic stem cells

    OpenAIRE

    Bonde, Sabrina; Pedram, Mehrdad; Stultz, Ryan; Zavazava, Nicholas

    2010-01-01

    Bone marrow transplantation is a curative treatment for many diseases, including leukemia, autoimmune diseases, and a number of immunodeficiencies. Recently, it was claimed that bone marrow cells transdifferentiate, a much desired property as bone marrow cells are abundant and therefore could be used in regenerative medicine to treat incurable chronic diseases. Using a Cre/loxP system, we studied cell fusion after bone marrow transplantation. Fused cells were chiefly Gr-1+, a myeloid cell mar...

  19. Quantitative characterization of cell behaviors through cell cycle progression via automated cell tracking.

    Directory of Open Access Journals (Sweden)

    Yuliang Wang

    Full Text Available Cell behaviors are reflections of intracellular tension dynamics and play important roles in many cellular processes. In this study, temporal variations in cell geometry and cell motion through cell cycle progression were quantitatively characterized via automated cell tracking for MCF-10A non-transformed breast cells, MCF-7 non-invasive breast cancer cells, and MDA-MB-231 highly metastatic breast cancer cells. A new cell segmentation method, which combines the threshold method and our modified edge based active contour method, was applied to optimize cell boundary detection for all cells in the field-of-view. An automated cell-tracking program was implemented to conduct live cell tracking over 40 hours for the three cell lines. The cell boundary and location information was measured and aligned with cell cycle progression with constructed cell lineage trees. Cell behaviors were studied in terms of cell geometry and cell motion. For cell geometry, cell area and cell axis ratio were investigated. For cell motion, instantaneous migration speed, cell motion type, as well as cell motion range were analyzed. We applied a cell-based approach that allows us to examine and compare temporal variations of cell behavior along with cell cycle progression at a single cell level. Cell body geometry along with distribution of peripheral protrusion structures appears to be associated with cell motion features. Migration speed together with motion type and motion ranges are required to distinguish the three cell-lines examined. We found that cells dividing or overlapping vertically are unique features of cell malignancy for both MCF-7 and MDA-MB-231 cells, whereas abrupt changes in cell body geometry and cell motion during mitosis are unique to highly metastatic MDA-MB-231 cells. Taken together, our live cell tracking system serves as an invaluable tool to identify cell behaviors that are unique to malignant and/or highly metastatic breast cancer cells.

  20. Plant stem cell niches.

    Science.gov (United States)

    Aichinger, Ernst; Kornet, Noortje; Friedrich, Thomas; Laux, Thomas

    2012-01-01

    Multicellular organisms possess pluripotent stem cells to form new organs, replenish the daily loss of cells, or regenerate organs after injury. Stem cells are maintained in specific environments, the stem cell niches, that provide signals to block differentiation. In plants, stem cell niches are situated in the shoot, root, and vascular meristems-self-perpetuating units of organ formation. Plants' lifelong activity-which, as in the case of trees, can extend over more than a thousand years-requires that a robust regulatory network keep the balance between pluripotent stem cells and differentiating descendants. In this review, we focus on current models in plant stem cell research elaborated during the past two decades, mainly in the model plant Arabidopsis thaliana. We address the roles of mobile signals on transcriptional modules involved in balancing cell fates. In addition, we discuss shared features of and differences between the distinct stem cell niches of Arabidopsis.

  1. Bacterial Cell Wall Components

    Science.gov (United States)

    Ginsberg, Cynthia; Brown, Stephanie; Walker, Suzanne

    Bacterial cell-surface polysaccharides cells are surrounded by a variety of cell-surface structures that allow them to thrive in extreme environments. Components of the cell envelope and extracellular matrix are responsible for providing the cells with structural support, mediating intercellular communication, allowing the cells to move or to adhere to surfaces, protecting the cells from attack by antibiotics or the immune system, and facilitating the uptake of nutrients. Some of the most important cell wall components are polysaccharide structures. This review discusses the occurrence, structure, function, and biosynthesis of the most prevalent bacterial cell surface polysaccharides: peptidoglycan, lipopolysaccharide, arabinogalactan, and lipoarabinomannan, and capsular and extracellular polysaccharides. The roles of these polysaccharides in medicine, both as drug targets and as therapeutic agents, are also described.

  2. What are Stem Cells?

    Directory of Open Access Journals (Sweden)

    Ahmadshah Farhat

    2014-05-01

    Full Text Available   Stem cells are undifferentiated self regenerating multi potential cells. There are three types of stem cells categories by the ability to form after cells and correlated with the body’s development process. Totipotent: these stem cells can form an entire organism such as fertilized egg. Ploripotent: ploripotent cells are those that can form any cell in the body but cannot form an entire organism such as developing embryo’s totipotent cells become ploripotent  Multipotent: Multi potent stem cells are those that can only form specific cells in the body such as blood cells based. Based on the sources of stem cells we have three types of these cells: Autologous: Sources of the patient own cells are (Autologous either the cells from patient own body or his or her cord blood. For this type of transplant the physician now usually collects the periphery rather than morrow because the procedure is easier on like a bane morrow harvest it take place outside of an operating room, and the patient does not to be under general unsetting . Allogenic: Sources of stem cells from another donore are primarily relatives (familial allogenic or completely unrelated donors. Xenogenic: In these stem cells from different species are transplanted e .g striatal porcine fetal mesan cephalic (FVM xenotransplants for Parkinson’s disease. On sites of isolation such as embryo, umbilical cord and other body tissues stem cells are named embnyonic, cord blood, and adult stem cells. The scope of results and clinical application of stem cells are such as: Neurodegenerative conditions (MS,ALS, Parkinson’s, Stroke, Ocular disorders- Glaucoma, retinitis Pigmentosa (RP, Auto Immune Conditions (Lupus, MS,R. arthritis, Diabetes, etc, Viral Conditions (Hepatitis C and AIDS, Heart Disease, Adrenal Disorders, Injury(Nerve, Brain, etc, Anti aging (hair, skin, weight control, overall well being/preventive, Emotional disorders, Organ / Tissue Cancers, Blood cancers, Blood diseases

  3. Induction of Functional Hair-Cell-Like Cells from Mouse Cochlear Multipotent Cells

    Directory of Open Access Journals (Sweden)

    Quanwen Liu

    2016-01-01

    Full Text Available In this paper, we developed a two-step-induction method of generating functional hair cells from inner ear multipotent cells. Multipotent cells from the inner ear were established and induced initially into progenitor cells committed to the inner ear cell lineage on the poly-L-lysine substratum. Subsequently, the committed progenitor cells were cultured on the mitotically inactivated chicken utricle stromal cells and induced into hair-cell-like cells containing characteristic stereocilia bundles. The hair-cell-like cells exhibited rapid permeation of FM1-43FX. The whole-cell patch-clamp technique was used to measure the membrane currents of cells differentiated for 7 days on chicken utricle stromal cells and analyze the biophysical properties of the hair-cell-like cells by recording membrane properties of cells. The results suggested that the hair-cell-like cells derived from inner ear multipotent cells were functional following differentiation in an enabling environment.

  4. Pluripotent Stem Cells for Schwann Cell Engineering

    NARCIS (Netherlands)

    Ma, Ming-San; Boddeke, Erik; Copray, Sjef

    Tissue engineering of Schwann cells (SCs) can serve a number of purposes, such as in vitro SC-related disease modeling, treatment of peripheral nerve diseases or peripheral nerve injury, and, potentially, treatment of CNS diseases. SCs can be generated from autologous stem cells in vitro by

  5. Regulation of cell polarity by cell adhesion receptors.

    Science.gov (United States)

    Ebnet, Klaus; Kummer, Daniel; Steinbacher, Tim; Singh, Amrita; Nakayama, Masanori; Matis, Maja

    2017-07-22

    The ability of cells to polarize is an intrinsic property of almost all cells and is required for the devlopment of most multicellular organisms. To develop cell polarity, cells integrate various signals derived from intrinsic as well as extrinsic sources. In the recent years, cell-cell adhesion receptors have turned out as important regulators of cellular polarization. By interacting with conserved cell polarity proteins, they regulate the recruitment of polarity complexes to specific sites of cell-cell adhesion. By initiating intracellular signaling cascades at those sites, they trigger their specific subcellular activation. Not surprisingly, cell-cell adhesion receptors regulate diverse aspects of cell polarity, including apico-basal polarity in epithelial and endothelial cells, front-to-rear polarity in collectively migrating cells, and planar cell polarity during organ development. Here, we review the recent developments highlighting the central roles of cell-cell adhesion molecules in the development of cell polarity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Cell cycle control by components of cell anchorage

    OpenAIRE

    Gad, Annica

    2005-01-01

    Extracellular factors, such as growth factors and cell anchorage to the extracellular matrix, control when and where cells may proliferate. This control is abolished when a normal cell transforms into a tumour cell. The control of cell proliferation by cell anchorage was elusive and less well studied than the control by growth factors. Therefore, we aimed to clarify at what points in the cell cycle and through which molecular mechanisms cell anchorage controls cell cycle pro...

  7. The cell cycle as a brake for β-cell regeneration from embryonic stem cells.

    Science.gov (United States)

    El-Badawy, Ahmed; El-Badri, Nagwa

    2016-01-13

    The generation of insulin-producing β cells from stem cells in vitro provides a promising source of cells for cell transplantation therapy in diabetes. However, insulin-producing cells generated from human stem cells show deficiency in many functional characteristics compared with pancreatic β cells. Recent reports have shown molecular ties between the cell cycle and the differentiation mechanism of embryonic stem (ES) cells, assuming that cell fate decisions are controlled by the cell cycle machinery. Both β cells and ES cells possess unique cell cycle machinery yet with significant contrasts. In this review, we compare the cell cycle control mechanisms in both ES cells and β cells, and highlight the fundamental differences between pluripotent cells of embryonic origin and differentiated β cells. Through critical analysis of the differences of the cell cycle between these two cell types, we propose that the cell cycle of ES cells may act as a brake for β-cell regeneration. Based on these differences, we discuss the potential of modulating the cell cycle of ES cells for the large-scale generation of functionally mature β cells in vitro. Further understanding of the factors that modulate the ES cell cycle will lead to new approaches to enhance the production of functional mature insulin-producing cells, and yield a reliable system to generate bona fide β cells in vitro.

  8. Regulatory T cells and B cells: implication on autoimmune diseases

    OpenAIRE

    Wang, Ping; Zheng, Song Guo

    2013-01-01

    The regulatory T (Treg) cells play an important role in the maintenance of homeostasis and the prevention of autoimmune diseases. Although most studies are focusing on the role of Treg cells in T cells and T cells-mediated diseases, these cells also directly affect B cells and other non-T cells. This manuscript updates the role of Treg cells on the B cells and B cell-mediated diseases. In addition, the mechanisms whereby Treg cells suppress B cell responses have been discussed.

  9. Sickle Cell Trait

    Science.gov (United States)

    ... cell trait toolkit » Sickle cell trait fact sheet » SCT and Athletes Some people with SCT have been ... ill. Recommendations on Screening of Student Athletes for SCT Recommendations of the Advisory Committee on Heritable Disorders ...

  10. Antioxidants: Protecting Healthy Cells

    Science.gov (United States)

    ... and Nutrients Antioxidants - Protecting Healthy Cells Print Email Antioxidants - Protecting Healthy Cells Reviewed by Taylor Wolfram, MS, ... to cardiovascular disease and certain types of cancers. Antioxidants — such as vitamins C and E and carotenoids, ...

  11. Fuel cells: Project Volta

    Energy Technology Data Exchange (ETDEWEB)

    Vellone, R.; Di Mario, F.

    1987-09-01

    This paper discusses research and development in the field of fuel cell power plants. Reference is made to the Italian research Project Volta. Problems related to research program financing and fuel cell power plant marketing are discussed.

  12. Border cell release

    DEFF Research Database (Denmark)

    Mravec, Jozef

    2017-01-01

    Plant border cells are specialised cells derived from the root cap with roles in the biomechanics of root growth and in forming a barrier against pathogens. The mechanism of highly localised cell separation which is essential for their release to the environment is little understood. Here I present...... in situ analysis of Brachypodium distachyon, a model organism for grasses which possess type II primary cell walls poor in pectin content. Results suggest similarity in spatial dynamics of pectic homogalacturonan during dicot and monocot border cell release. Integration of observations from different...... species leads to the hypothesis that this process most likely does not involve degradation of cell wall material but rather employs unique cell wall structural and compositional means enabling both the rigidity of the root cap as well as detachability of given cells on its surface....

  13. Giant Cell Arteritis

    Science.gov (United States)

    Giant cell arteritis is a disorder that causes inflammation of your arteries, usually in the scalp, neck, and arms. ... arteries, which keeps blood from flowing well. Giant cell arteritis often occurs with another disorder called polymyalgia ...

  14. Fluorescence live cell imaging.

    Science.gov (United States)

    Ettinger, Andreas; Wittmann, Torsten

    2014-01-01

    Fluorescence microscopy of live cells has become an integral part of modern cell biology. Fluorescent protein (FP) tags, live cell dyes, and other methods to fluorescently label proteins of interest provide a range of tools to investigate virtually any cellular process under the microscope. The two main experimental challenges in collecting meaningful live cell microscopy data are to minimize photodamage while retaining a useful signal-to-noise ratio and to provide a suitable environment for cells or tissues to replicate physiological cell dynamics. This chapter aims to give a general overview on microscope design choices critical for fluorescence live cell imaging that apply to most fluorescence microscopy modalities and on environmental control with a focus on mammalian tissue culture cells. In addition, we provide guidance on how to design and evaluate FP constructs by spinning disk confocal microscopy. © 2014 Elsevier Inc. All rights reserved.

  15. FUEL CELL ELECTRODE MATERIALS

    Science.gov (United States)

    FUEL CELL ELECTRODE MATERIALS. RAW MATERIAL SELECTION INFLUENCES POLARIZATION BUT IS NOT A SINGLE CONTROLLING FACTOR. AVAILABLE...DATA INDICATES THAT AN INTERRELATIONSHIP OF POROSITY, AVERAGE PORE VOLUME, AND PERMEABILITY CONTRIBUTES TO ELECTRODE FUEL CELL BEHAVIOR.

  16. Basal cell nevus syndrome

    Science.gov (United States)

    ... nevus syndrome Basal cell nevus syndrome - face References Evans DG, Farndon PA. Nevoid basal cell carcinoma syndrome. ... A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among ...

  17. Merkel Cell Carcinoma

    Science.gov (United States)

    ... H, Shuda M, Chang Y, et al . “Clonal integration of a polyomavirus in human Merkel cell carcinoma.” ... look at it under the microscope. This process continues until the surgeon no longer sees cancer cells. ...

  18. Separators for electrochemical cells

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Steven Allen; Anakor, Ifenna Kingsley; Farrell, Greg Robert

    2018-01-16

    Provided are separators for use in an electrochemical cell comprising (a) an inorganic oxide and (b) an organic polymer, wherein the inorganic oxide comprises organic substituents. Also provided are electrochemical cells comprising such separators.

  19. Dendritic cell vaccines.

    Science.gov (United States)

    Mosca, Paul J; Lyerly, H Kim; Clay, Timothy M; Morse, Michael A; Lyerly, H Kim

    2007-05-01

    Dendritic cells are antigen-presenting cells that have been shown to stimulate tumor antigen-specific T cell responses in preclinical studies. Consequently, there has been intense interest in developing dendritic cell based cancer vaccines. A variety of methods for generating dendritic cells, loading them with tumor antigens, and administering them to patients have been described. In recent years, a number of early phase clinical trials have been performed and have demonstrated the safety and feasibility of dendritic cell immunotherapies. A number of these trials have generated valuable preliminary data regarding the clinical and immunologic response to DC-based immunotherapy. The emphasis of dendritic cell immunotherapy research is increasingly shifting toward the development of strategies to increase the potency of dendritic cell vaccine preparations.

  20. Stem Cell Transplant

    Science.gov (United States)

    ... Graft-versus-host disease: A potential risk when stem cells come from donors If you receive a transplant ... medications and blood products into your body. Collecting stem cells for transplant If a transplant using your own ...

  1. NIA Aging Cell Repository

    Data.gov (United States)

    Federal Laboratory Consortium — To facilitate aging research on cells in culture, the NIA provides support for the NIA Aging Cell Repository, located at the Coriell Institute for Medical Research...

  2. Sickle cell anemia.

    OpenAIRE

    ŘÍHOVÁ, Tereza

    2013-01-01

    This thesis is about the disease called sickle cell anemia, or drepanocytosis. In this thesis is described the history of the disease, pathophysiology, laboratory features, various clinical features, diferencial diagnosis, quality of life in sickle cell anemia and therapy.

  3. Mesenchymal Stem Cells

    DEFF Research Database (Denmark)

    Horwood, Nicole J.; Dazzi, Francesco; Zaher, Walid

    2012-01-01

    and differentiation of hematopoietic stem cells (HSC) and hematopoiesis. These cells have been described as important immunoregulators due to their ability to suppress T cells proliferation. MSC can also directly contribute to tissue repair by migrating to sites of injury and providing a source of cells......Mesenchymal stem cells (MSC) are stem cell populations present among the bone marrow stroma and a number of other tissues that are capable of multi-lineage differentiation into mesoderm-type cells such as osteoblasts, adipocytes and chondrocytes. MSC provide supportive stroma for growth...... for differentiation and/or providing bystander support for resident stromal cells. This chapter discusses the cellular and molecular properties of MSC, the mechanisms by which they can modulate immune responses and the clinical applications of MSC in disorders such as graft-versus-host disease and aplastic anaemia...

  4. Diagram of Cell to Cell Communication

    Science.gov (United States)

    2002-01-01

    Diagram depicts the importance of cell-cell communication as central to the understanding of cancer growth and progression, the focus of the NASA bioreactor demonstration system (BDS-05) investigation. Microgravity studies will allow us to unravel the signaling and communication between these cells with the host and potential development of therapies for the treatment of cancer metastasis. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: Emory University.

  5. Cell Factory Engineering

    DEFF Research Database (Denmark)

    Davy, Anne Mathilde; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    2017-01-01

    focused on individual strategies or cell types, but collectively they fall under the broad umbrella of a growing field known as cell factory engineering. Here we condense >130 reviews and key studies in the art into a meta-review of cell factory engineering. We identified 33 generic strategies......-review provides general strategy guides for the broad range of applications of rational engineering of cell factories....

  6. Anterior Horn Cell Diseases

    Directory of Open Access Journals (Sweden)

    Merve Firinciogullari

    2016-09-01

    Full Text Available The anterior horn cells control all voluntary movement. Motor activity, respiratory, speech, and swallowing functions are dependent upon signals from the anterior horn cells. Diseases that damage the anterior horn cells, therefore, have a profound impact. Symptoms of anterior horn cell loss (weakness, falling, choking lead patients to seek medical attention. In this article, anterior horn diseases were reviewed, diagnostic criteria and management were discussed in detail. [Archives Medical Review Journal 2016; 25(3.000: 269-303

  7. Skeletal (stromal) stem cells

    DEFF Research Database (Denmark)

    Abdallah, Basem M; Kermani, Abbas Jafari; Zaher, Walid

    2015-01-01

    Skeletal (marrow stromal) stem cells (BMSCs) are a group of multipotent cells that reside in the bone marrow stroma and can differentiate into osteoblasts, chondrocytes and adipocytes. Studying signaling pathways that regulate BMSC differentiation into osteoblastic cells is a strategy....../preadipocyte factor 1 (Dlk1/Pref-1), the Wnt co-receptor Lrp5 and intracellular kinases. This article is part of a Special Issue entitled: Stem Cells and Bone....

  8. Red blood cell production

    Science.gov (United States)

    ... bone marrow of bones. Stem cells in the red bone marrow called hemocytoblasts give rise to all of the formed elements in blood. If a hemocytoblast commits to becoming a cell called a proerythroblast, it will develop into a new red blood cell. The formation of a red blood ...

  9. Criticality in cell differentiation

    Indian Academy of Sciences (India)

    Indrani Bose

    2017-11-09

    Nov 9, 2017 ... Cell differentiation is an important process in living organisms. Differentiation is mostly based on binary decisions with the progenitor cells choosing between two specific lineages. The differentiation dynamics have both deterministic and stochastic components. Several theoretical studies suggest that cell ...

  10. NCAM regulates cell motility

    DEFF Research Database (Denmark)

    Prag, Søren; Lepekhin, Eugene A; Kolkova, Kateryna

    2002-01-01

    Cell migration is required during development of the nervous system. The regulatory mechanisms for this process, however, are poorly elucidated. We show here that expression of or exposure to the neural cell adhesion molecule (NCAM) strongly affected the motile behaviour of glioma