WorldWideScience

Sample records for bedrock

  1. GeologicBedrock_BEDROCK9

    Data.gov (United States)

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

  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. 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...

  4. 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...

  5. 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...

  6. Groundwater in crystalline bedrock

    International Nuclear Information System (INIS)

    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)

  7. Saline groundwater in crystalline bedrock

    International Nuclear Information System (INIS)

    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.)

  8. 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

  9. A Computationally Efficient Bedrock Model

    Science.gov (United States)

    Fastook, J. L.

    2002-05-01

    Full treatments of the Earth's crust, mantle, and core for ice sheet modeling are often computationally overwhelming, in that the requirements to calculate a full self-gravitating spherical Earth model for the time-varying load history of an ice sheet are considerably greater than the computational requirements for the ice dynamics and thermodynamics combined. For this reason, we adopt a ``reasonable'' approximation for the behavior of the deforming bedrock beneath the ice sheet. This simpler model of the Earth treats the crust as an elastic plate supported from below by a hydrostatic fluid. Conservation of linear and angular momentum for an elastic plate leads to the classical Poisson-Kirchhoff fourth order differential equation in the crustal displacement. By adding a time-dependent term this treatment allows for an exponentially-decaying response of the bed to loading and unloading events. This component of the ice sheet model (along with the ice dynamics and thermodynamics) is solved using the Finite Element Method (FEM). C1 FEMs are difficult to implement in more than one dimension, and as such the engineering community has turned away from classical Poisson-Kirchhoff plate theory to treatments such as Reissner-Mindlin plate theory, which are able to accommodate transverse shear and hence require only C0 continuity of basis functions (only the function, and not the derivative, is required to be continuous at the element boundary) (Hughes 1987). This method reduces the complexity of the C1 formulation by adding additional degrees of freedom (the transverse shear in x and y) at each node. This ``reasonable'' solution is compared with two self-gravitating spherical Earth models (1. Ivins et al. (1997) and James and Ivins (1998) } and 2. Tushingham and Peltier 1991 ICE3G run by Jim Davis and Glenn Milne), as well as with preliminary results of residual rebound rates measured with GPS by the BIFROST project. Modeled responses of a simulated ice sheet experiencing a

  10. 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

  11. 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...

  12. 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

  13. SFR site investigation. Bedrock Hydrogeochemistry

    International Nuclear Information System (INIS)

    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 δ18O values show a wide variation (-15.5 to -7.5 per mille V-SMOW) similar

  14. CHARACTERIZATION OF FRACTURED BEDROCK FOR STEAM INJECTION

    Science.gov (United States)

    The most difficult setting in which to conduct groundwater remediation is that where chlorinated solvents have penetrated fractured bedrock. To demonstrate the potential viability of steam injection as a means of groundwater clean-up in this type of environment, steam will be in...

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

    International Nuclear Information System (INIS)

    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

  16. 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

  17. Atmospheric Methane Contributions From Fractured Bedrock Aquifers

    Science.gov (United States)

    Marrin, D. L.

    2013-05-01

    Groundwater is not normally considered as an important contributor of atmospheric methane because the organic carbon content of aquifers is too low to sustain significant methanogenesis. Also, groundwater-generated methane partitions into the gas phase of the overlying soil, where it either dissolves in the pore water or is oxidized to carbon dioxide by methanotrophs. There are, however, localized conditions (related to human activities and hydrogeologic conditions) under which atmospheric contributions of groundwater-generated methane occur at the ground surface. Storing and transporting liquid petroleum products in the subsurface has resulted in the local introduction of high concentrations of degradable organic carbon and the creation of redox conditions that favor methanogenesis over more oxidative biodegradation pathways. Groundwater overlain by fractured bedrock, rather than by unconsolidated porous media, creates a situation where CH4 migrates through discrete fractures, thus limiting the soil volume and the surface area available for methanotrophic activity. The spatial distribution of methane in thin surface soils overlying bedrock suggests that CH4 migrates via fracture networks and that CH4 oxidation is a factor of about 50 less than that measured in typical unconsolidated soils. Atmospheric flux rates associated with contaminated bedrock aquifers were on the order of several grams of carbon (as CH4) per square meter, which is less than that reported for well documented sources (e.g., rice paddies) and probably represents a minor worldwide contribution. Nonetheless, these aquifers can represent an important localized source, can shift soils from a sink to a source of methane, and can permit petroleum products to load carbon (as biogenic CH4 and CO2) to the atmosphere without ever being combusted.

  18. Bedrock model of the Veitsivaara area

    International Nuclear Information System (INIS)

    Site investigations were carried out at Veitsivaara, in 1987-1991 in accordance with an investigation programme for radioactive waste disposal drawn up by Teollisuuden Voima Oy (TVO). The site was modelled in terms of rock types, fracturing, fracture structures and geophysical conditions, the main focus of examination was on fracturing and associated hydraulic conductivity. The various properties of the bedrock structures were classified by means a three-dimensional model. The descriptions of the models were stored in a computer system for illustration purposes. The rock types at Veitsivaara are tonalite gneiss, Tuliniemet potassium granite, amphipolite, granite porphyry and metadiabase, the last two of which occur in dykes

  19. Fractal Character of China Bedrock Coastline

    Institute of Scientific and Technical Information of China (English)

    朱晓华

    2004-01-01

    Fractal theory was applied to a preliminary discussion of the fractal character and formation mechanism of the coastline of the bedrock coast of China on the basis of GIS (Geographical Information System). Some significant conclusions were drawn:(1) The fractal dimensions of the coastline and linear structures of Liaodong Peninsula are 1.0093 and 1.0246 respectively, those of Shandong Peninsula are 1.019 and 1.021 respectively, etc.(2) The fractal dimensions of coastlines of Liaodong Peninsula, Shandong Peninsula, Zhejiang and Fujian-Guangdong tend to increase with the spatial change from north to south.(3)The regional linear structures(including faults)control the basic trends and fractal dimensions of coastlines as a whole in the regions of the bedrock coast of China:the more the controlling effect of linear structures, the smaller the fractal dimensions of coastlines.(4)The substantial constituents of coast and biologic function both play an important role in affecting the fractal dimensions of coastlines of Liaodong Peninsula, Shandong Peninsula, Zhejiang, Fujian-Guangdong and Taiwan Island.

  20. Bedrock Model of the Syyry area

    International Nuclear Information System (INIS)

    Preliminary site investigations implemented in accordance with the research programme drawn up by Teollisuuden Voima Oy (TVO) were carried out at Syyry (in Finland) in 1987-1992. Models of the site were compiled and used for describing the rock types, fracturing, fracture structures and geohydrological conditions, the main emphasis being on the examination of the bedrock fracturing and related hydraulic conductivity. Three-dimensional models were used for the classification of the various properties of the bedrock structures. The descriptive models were gathered into a computer system to facilitate illustration and storage. The main rock type at Syyry is tonalite. A mica gneiss formation SE of the investigation site dips towards the NW and delimits the tonalite as far as the central part of the investigation site. The miga gneiss has a heterogeneous composition and includes intermediate layers consisting of quartz feldspar schist and amphibolite. There are mafic formations in the vicinity of the investigation site. The intrusive rocks have been deformed during three plastic and three mainly brittle deformation stages. (47 refs., 61 figs.)

  1. Efficacy of bedrock erosion by subglacial water flow

    OpenAIRE

    Beaud, F.; G. E. Flowers; Venditti, J. G.

    2016-01-01

    Bedrock erosion by sediment-bearing subglacial water remains little-studied; however, the process is thought to contribute to bedrock erosion rates in glaciated landscapes and is implicated in the excavation of tunnel valleys and the incision of inner gorges. We adapt physics-based models of fluvial abrasion to the subglacial environment, assembling the first model designed to quantify bedrock erosion caused by transient subglacial water flow. The subglacial drainage model c...

  2. VTT test borehole for bedrock investigations

    International Nuclear Information System (INIS)

    A borehole of depth 150 m and diameter 56 mm has been drilled in the area adjacent to the premises of the Technical Research Centre of Finland (VTT) at Otaniemi, Espoo, for the purposes of calibrating geophysical measurements devices. This report presents the test results obtained so far and illustrates the processing of these, in which the various measurements are plotted as curves and combinations of curves. The interpretations provided so far consists of analyses of lithological variations, bedrock fracturing, the nature and occurrence of fracture zones and groundwater flow patterns. Samples were taken from those parts of the core shown by the borehole measurements to be homogenous and thin sections made from these for mineralogical determinations. The rock mechanical and petrophysical properties of the same points were examined. The core is in the possession of VTT, and the hole itself is available to outsiders for the calibration and testing of borehole measurement equipment. (orig.). (21 refs., 13 figs., 5 tabs.)

  3. Bedrock model of the Kivetty area

    International Nuclear Information System (INIS)

    Preliminary site investigations were carried out at Kivetty (in Finland), in 1987-1992 in accordance with the investigation programme drawn up by Teollisuuden Voima Oy (TVO). The site was modelled in terms of rock type, fracturing, fracture structures and geohydrological conditions, with the main emphasis being placed on fracturing and associated hydraulic conductivity. The various properties of the bedrock structures were classified in relation to a three-dimensional model. The descriptions of the models were stored in a computer system for the purpose of illustration. The principal rock types encountered at the Kivetty site are porphyritic granodiorite and porphyritic granite, in addition to which even-grained granite and granodiorite, gabbro, and small felsic and mafic veins occur. The rocks have undergone two distinct phases of deformation. (41 refs., 50 figs.)

  4. Bedrock model of the Olkiluoto area

    International Nuclear Information System (INIS)

    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.)

  5. VTT test borehole for bedrock investigations

    Science.gov (United States)

    Okko, Olli; Hassinen, Pertti; Front, Kai

    1994-02-01

    A borehole of depth 150 m and diameter 56 mm has been drilled in the area adjacent to the premises of the Technical Research Center of Finland (VTT) at Otaniemi, Espoo, for the purposes of calibrating geophysical measurement devices. The report presents the test results obtained so far and illustrates the processing of these, in which the various measurements are plotted as curves and combinations of curves. The interpretations provided so far consist of analyses of lithological variations, bedrock fracturing, the nature and occurrence of fracture zones and groundwater flow patterns. Samples were taken from those parts of the core shown by the borehole measurements to be homogeneous and thin sections made from these for mineralogical determinations. The rock mechanical and petrophysical properties of the same points were examined. The core is in the possession of VTT, and the hole itself is available to outsiders for the calibration and testing of borehole measurement equipment.

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

    Data.gov (United States)

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

  7. Bedrock Hydrogeology-Site investigation SFR

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

  10. 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

  11. 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

  12. Geology, Bedrock - BEDROCK_GEOLOGY_RGM_250K_IN: Bedrock geology of Indiana, from the Regional Geologic Map Series of the Indiana Geological Survey (Indiana Geological Survey, 1:250,000, Polygon Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — BEDROCK_GEOL_RGM_IN is a polygon shapefile that shows the bedrock geology of the state of Indiana, produced from the Indiana Geological Survey Regional Geologic Map...

  13. Postglacial deformation of bedrock in Finland

    International Nuclear Information System (INIS)

    Glacial isostatic adjustment controls the three-dimensional deformation in Fennoscandia. Maximum vertical uplift rates based on the GPS measurements are about 11 mm/yr and horizontal motions are up to 2 mm/yr. Tectonic component is about 10% of the land uplift (or 1 mm/yr). Horizontal motions are directed outward from area of the fastest uplift. Horizontal tectonic motions are also less than 1 mm/yr. Seismic activity in Finland is low and heterogeneously distributed and the earthquake density maximums and the areas of postglacial faults have a spatial correlation. Detailed geodetic surveys indicate that crustal deformation occurs unevenly. However, the bedrock in Finland is so fractured that the deformation is distributed over a number of structures and that deformations and displacements along individual structures are very small and difficult to resolve. Fault intersections can form a locked area where stresses large enough to trigger intraplate earthquakes can build up. In the absence of intersections, the pre-existing faults can creep at a lower stress threshold. In Fennoscandia, plate-boundary tectonic stresses drive the regional compressive stress field, but to account for the current level of seismicity the glacial isostatic adjustment has a very important role. Brittle crust is near the point of failure, and, consequently, small changes, like glacial rebound related, (0.1 Mpa) in the state of stress can nucleate earthquakes are sufficient to reactive optimally oriented pre-excising weaknesses. Stress orientations inferred from the strain measurements of the first order triangulation network and seismological stress data shows (a) the dominating ridge-push/mantle drag related compression and, (b) evidence on significant local variations of the surface stress field influenced by the orientation of major fracture zones. Postglacial faults are re-activated old faults and the areas of postglacial faulting are still the most seismically active areas in

  14. Bedrock composition limits mountain ecosystem productivity and landscape evolution (Invited)

    Science.gov (United States)

    Riebe, C. S.; Hahm, W.; Lukens, C.

    2013-12-01

    We used measurements of bedrock geochemistry, forest productivity and cosmogenic nuclides to explore connections among lithology, ecosystem productivity and landscape evolution across a lithosequence of 21 sites in the Sierra Nevada Batholith, California. Our sites span a narrow range in elevations and thus share similar climatic conditions. Meanwhile, underlying bedrock varies from granite to diorite and spans nearly the entire range of geochemical compositions observed in Cordilleran granitoids. Land cover varies markedly, from groves of Giant Sequoia, the largest trees on Earth, to pluton-spanning swaths of little or no soil and vegetative cover. This is closely reflected in measures of forest productivity, such as remotely sensed tree-canopy cover, which varies by more than an order of magnitude across our sites and often changes abruptly at mapped contacts between rock types. We find that tree-canopy cover is closely correlated with the concentrations in bedrock of major and minor elements, including several plant-essential nutrients. For example, tree-canopy cover is virtually zero where there is less than 0.3 mg/g phosphorus in bedrock. Erosion rates from these nearly vegetation-free, nutrient deserts are more than 2.5 times slower on average than they are from surrounding, relatively nutrient-rich, soil-mantled bedrock. Thus by influencing soil and forest cover, bedrock nutrient concentrations may provoke weathering-limited erosion and thus may strongly regulate landscape evolution. Our analysis suggests that variations in bedrock nutrient concentrations can also provoke an intrinsic limitation on primary productivity. These limitations appear to apply across all our sites. To the extent that they are broadly representative of conditions in granitic landscapes elsewhere around the world, our results are consistent with widespread, but previously undocumented lithologic control of the distribution and diversity of vegetation in mountainous terrain.

  15. Particle dynamics: The continuum of bedrock to alluvial river segments

    Science.gov (United States)

    Wohl, Ellen

    2015-07-01

    Particle dynamics refers to production, erosion, transport, and storage of particulate material including mineral sediment and organic matter. Particle dynamics differ significantly between the end members of bedrock and alluvial river segments and between alluvial river segments with different grain-size distributions. Bedrock segments are supply limited and resistant to change, with relatively slow, linear adjustments and predominantly erosion and transport. Particle dynamics in alluvial segments, in contrast, are transport limited and dominated by storage of mineral sediment and production of organic matter. Alluvial segments are resilient to change, with relatively rapid, multidirectional adjustments and stronger internal influences because of feedbacks between particles and biota. Bedrock segments are the governors of erosion within a river network, whereas alluvial segments are the biogeochemical reactors. Fundamental research questions for both types of river segments center on particle dynamics, which limit network-scale incision in response to base level fall (bedrock segments) and habitat, biogeochemical reactions, and biomass production (alluvial segments). These characterizations illuminate how the spatial arrangement of bedrock and alluvial segments within a river network influence network-scale resistance and resilience to external changes in relative base level, climate, and human activities.

  16. Detection of Seismic Bedrock Using Radial Receiver Function

    Science.gov (United States)

    Wu, Cheng-Feng; Huang, Huey-Chu

    2016-06-01

    The receiver function (RF) method has been widely applied to estimate velocity structures of Earth's crust and mantle using teleseismic data. In this study, we perform a RF iterative deconvolution method to detect the depth variations of seismic bedrock in the Taipei basin and Chiayi area. We use strong motion data recorded by five and seven stations in the Taipei basin and Chiayi area, respectively. The Ps-P times appear at about 0.235-0.93 s for the Taipei basin and 1.015-1.685 s for the Chiayi area. The time differences imply gradually increases of the bedrock depth from southeast to northwest in the Taipei basin and from east to west in the Chiayi area. Our results show that the method can efficiently detect depth variations of seismic bedrock which are consistent with those from other geophysical observations as well.

  17. 2-D NUMERICAL SIMULATION OF CRUSH BEDROCK RIVER

    Institute of Scientific and Technical Information of China (English)

    YIN Ze-gao; ZHANG Tu-qiao; SUN Dong-po; LI Guo-qing

    2004-01-01

    In this paper, the erosion-resisting coefficient was introduced to compute bed deformation in a crush bedrock river. In the case of crush bedrock, there has been no proper control equation to describe bed stability, which leads to difficulty in calculation of the bed deformation with conventional methods. The data from field survey were used to give the erosion-resisting capability with an appropriate coefficient. After the determination of longitudinal distribution expressed by polynomial regression and transversal distribution expressed by normal distribution function, the plane distribution of erosion-resisting coefficient in a crush bedrock river was obtained. With the computational results from a 2-D horizontal flow mathematical model, the erosion-resisting coefficient and controlling condition of local stability were employed to compute the values of bed deformation when riverbed is stable. The above method was applied in a case study, and the computational results of flow and bed deformations are in good agreement with physical model test data.

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

    International Nuclear Information System (INIS)

    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.)

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Follin, Sven (SF GeoLogic AB, Taeby (Sweden))

    2008-12-15

    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

  1. The amount of glacial erosion of the bedrock

    International Nuclear Information System (INIS)

    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

  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)

    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. Identification Of Rippability And Bedrock Depth Using Seismic Refraction

    International Nuclear Information System (INIS)

    Spatial variability of the bedrock with reference to the ground surface is vital for many applications in geotechnical engineering to decide the type of foundation of a structure. A study was done within the development area of Mutiara Damansara utilising the seismic refraction method using ABEM MK8 24 channel seismograph. The geological features of the subsurface were investigated and velocities, depth to the underlying layers were determined. The seismic velocities were correlated with rippability characteristics and borehole records. Seismic sections generally show a three layer case. The first layer with velocity 400-600 m/s predominantly consists of soil mix with gravel. The second layer with velocity 1600-2000 m/s is suggested to be saturated and weathered area. Both layers forms an overburden and generally rippable. The third layer represents granite bedrock with average depth and velocity 10-30 m and >3000 m/s respectively and it is non-rippable. Steep slope on the bedrock are probably the results of shear zones.

  6. Bedrock incision by bedload: insights from direct numerical simulations

    Science.gov (United States)

    Aubert, Guilhem; Langlois, Vincent J.; Allemand, Pascal

    2016-04-01

    Bedload sediment transport is one of the main processes that contribute to bedrock incision in a river and is therefore one of the key control parameters in the evolution of mountainous landscapes. In recent years, many studies have addressed this issue through experimental setups, direct measurements in the field, or various analytical models. In this article, we present a new direct numerical approach: using the classical methods of discrete-element simulations applied to granular materials, we explicitly compute the trajectories of a number of pebbles entrained by a turbulent water stream over a rough solid surface. This method allows us to extract quantitatively the amount of energy that successive impacts of pebbles deliver to the bedrock, as a function of both the amount of sediment available and the Shields number. We show that we reproduce qualitatively the behaviour observed experimentally by Sklar and Dietrich (2001) and observe both a "tool effect" and a "cover effect". Converting the energy delivered to the bedrock into an average long-term incision rate of the river leads to predictions consistent with observations in the field. Finally, we reformulate the dependency of this incision rate with Shields number and sediment flux, and predict that the cover term should decay linearly at low sediment supply and exponentially at high sediment supply.

  7. Soil mechanics and analysis of soils overlying cavitose bedrock

    International Nuclear Information System (INIS)

    The stability of the residual soils existing at the West Chestnut Ridge Site, Oak Ridge Reservation, Tennessee, was evaluated. The weathered bedrock below this residual soil contains numerous solution cavities, and several karst features were identified. The West Chestnut Ridge site was evaluated with respect to deformation and collapse of the residual soil into the bedrock cavities. A finite element analysis investigated the effects of bedrock cavity radius, thickness of soil overburden, and surface surcharge upon the deformational and stability characteristics of the residual soil. The results indicate that for small cavity radii, the thickness of the soil cover has little effect on the zone of yielded soil. For large cavity radii, a smaller zone of distressed soil occurs under thick soil cover than under thin soil cover. Dimensionless curves are presented to enable the prediction of the vertical extent of the zone of yielded soil for a range of site geometries. Although the thick soil deposits (100 feet or greater) typically found on the ridges result in high stresses adjacent to the cavity, the area of the distressed or yielded soil is small and unlikely to extend to the surface. In addition, the surface deformation or subsidence is expected to be minimal. Thus, the siting of waste facilities on the ridges where the overburden is maximum would tend to reduce the effects of deformation into the cavities. 29 refs., 37 figs., 7 tabs

  8. Nondestructive testing technology to characterize concrete dam/bedrock interface

    International Nuclear Information System (INIS)

    It is essential that there be knowledge of the in situ conditions and properties of the interface between the concrete and bedrock foundation when assessing the stability of hydraulic structures. Such information typically comes from core sampling and laboratory testing of specimens containing the concrete/bedrock interface. The approach only yields information on a small percentage of the contact area, and the test results may be affected by disturbance of the samples during coring with the result that interpretation is required to derive an average value for the condition of the contact. Nondestructive testing using ultrasonic velocity measurements including the use of tomographic imaging were evaluated as a means of obtaining additional information on a concrete dam foundation. An assessment was carried out based on the results of a field trial at a large gravity dam to determine the ability of these methods to provide greater confidence in estimating the condition of the concrete/bedrock interface. Field trials confirmed that ultrasonic testing methods are capable of identifying the general foundation profile, and the technology can also provide information regarding the general integrity of the contact zone. Such information taken in conjunction with the results of a coring and laboratory testing program can greatly improve confidence in the evaluation of the foundation contact condition and the selection of strength parameters used for assessment. 5 refs., 6 figs

  9. Experimental evidence for bedrock erosion by suspended sediment

    Science.gov (United States)

    Scheingross, J. S.; Brun, F.; Lo, D. Y.; Omerdin, K.; Lamb, M. P.

    2013-12-01

    Fluvial bedrock incision influences channel evolution and sets the pace of landscape lowering. Bedrock incision often occurs via abrasion, and existing theory is divided on the erosional efficiency of sediment transported in suspension versus bed load, due in part to a lack of data to test model predictions. This represents a major knowledge gap as suspended sediment can account for the majority of the total fluvial sediment load, and untested models make opposite predictions of bedrock erosion in steep channels and during large floods. We performed controlled abrasion mill experiments examining suspended and bed load erosion, making use of an erodible polyurethane foam substrate as a bedrock analog to overcome previous experimental limitations and allow for measureable suspension erosion. Our results show foam erodes similar to natural rock, where erodibility is a function of tensile strength and density. To explore the role of the mode of sediment transport on erosion, we varied sediment size from gravel (42 mm diameter) to medium sand (0.4 mm diameter), while holding fixed hydraulics, sediment load, and substrate strength. Under these conditions, volumetric erosion rates decreased across the bed load (~101 - 103 cm3/hr) to suspended load (~0.01 - 100 cm3/hr) transition due to lower near-bed sediment concentrations (~25 g/l vs. 115 g/l), slower settling velocity (0.09 m/s vs. 0.49 m/s), and viscous damping of impacts (for particle Stokes numbers less than ~75) for suspended particles. Our results provide direct experimental evidence of erosion by suspended load, and upscaling results to field scale shows suspension erosion can outpace bed load erosion by up to a factor ~4 during large floods which suspend coarse sand and gravel, and where suspended sediment dominates the total load. These results imply that suspension erosion may also dominate on very steep slopes where commonly used bedrock incision models (which ignore suspension erosion) predict zero erosion

  10. Natural attenuation of trichloroethylene in fractured shale bedrock.

    Science.gov (United States)

    Lenczewski, M; Jardine, P; McKay, L; Layton, A

    2003-07-01

    This paper describes one of the first well-documented field examples of natural attenuation of trichloroethylene (TCE) in groundwater in a fractured shale bedrock. The study was carried out adjacent to a former waste burial site in Waste Area Grouping 5 (WAG5) on the Oak Ridge Reservation, Oak Ridge, TN. A contaminant plume containing TCE and its daughter products were detected downgradient from the buried waste pits, with most of the contamination occurring in the upper 6 m of the bedrock. The monitoring well array consists of a 35-m-long transect of multilevel sampling wells, situated along a line between the waste pits and a seep which discharges into a small stream. Concentrations of volatile organic carbons (VOCs) were highest in the waste trenches and decreased with distance downgradient towards the seep. Sampling wells indicated the presence of overlapping plumes of TCE, cis-dichloroethylene (cDCE), vinyl chloride (VC), ethylene, ethane, and methane, with the daughter products extending further downgradient than the parent (TCE). This type of distribution suggests anaerobic biodegradation. Measurements of redox potential at the site indicated that iron-reduction, sulfate reduction, and potentially methanogensis were occurring and are conducive to dechlorination of TCE. Bacteria enrichment of groundwater samples revealed the presence of methanotrophs, methanogens, iron-reducing bacteria and sulfate-reducing bacteria, all of which have previously been implicated in anaerobic biodegradation of TCE. 16S rDNA sequence from DNA extracted from two wells were similar to sequences of organisms previously implicated in the anaerobic biodegradation of chlorinated solvents. The combined data strongly suggest that anaerobic biodegradation of the highly chlorinated compounds is occurring. Aerobic biodegradation may also be occurring in oxygenated zones, including near a seep where groundwater exits the site, or in the upper bedrock during seasonal fluctuations in water

  11. Composition of ground water in deep layers of bedrock

    International Nuclear Information System (INIS)

    The effect of different types of dissolved solids in ground water on corrosion and leaching is discussed. A suitable composition of water for leaching tests is indicated. The technique for sampling of water in bedrock at large depths is discussed. Water analyses from different investigations are presented and a probable interval of water composition as well as some maximum values are given. Very low oxygen concentrations, relatively high Fe2+ concentrations and low levels of organic substance can be expected. Leaching of bentonite can increase the concentration of organic substance

  12. 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

  13. Alluvium of antiquity: Polycyclic terraces in a confined bedrock valley

    Science.gov (United States)

    Kermode, S. J.; Cohen, T. J.; Reinfelds, I. V.; Nanson, G. C.; Pietsch, T. J.

    2012-02-01

    Confined river valleys are not the localities where long term preservation of alluvium would be expected. The 25 km long low gradient (0.0014 m.m - 1 ) confined valley setting of the Shoalhaven River has archived alluvium of middle Pleistocene age to maintain a relatively uniform channel as an efficient conduit for a wide range of flows in a confined bedrock valley of variable morphology. Single-grain optically stimulated luminescence (OSL) dating has identified polycyclic terraces up to 193 ka in age (marine isotope stage [MIS] 7) with lower terrace remnants dating from 173-140 ka (MIS 6) and 106 ka (MIS 5). Holocene alluvium 2-3.5 ka in age caps these old Pleistocene units and a well-constrained combination of one-dimensional and two-dimensional hydraulic modelling demonstrates that these polycyclic terraces are clearly within reach of the modern hydrological regime. The 106 ka terrace at 17 m above low flow is inundated by floods recurring on average every ~ 20 years, and the 140-193 ka terraces at 20-22 m are overtopped every 50-100 years. These ancient diachronous landforms exhibit complex depositional histories and are on-lapped by longitudinal benches of modern sand and gravel. Their polycyclic nature appears to be a response to flow reduction, using alluvium to adjust the boundary of the otherwise inflexible morphology of a bedrock gorge.

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

    International Nuclear Information System (INIS)

    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

  15. 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.

  16. Sorption processes of radiocesium in soil and bedrock

    International Nuclear Information System (INIS)

    Three recent studies on cesium sorption in soil and bedrock are reviewed. 137Cs, 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.

  17. Bedrock Model of the Syyry area. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    Saksa, P. [ed.; Ahokas, H. [Fintact Ky, Helsinki (Finland); Kuivamaeki, A.; Kurimo, M.; Paananen, M. [Geological Survey of Finland, Espoo (Finland); Anttila, P. [IVO International Oy, Vantaa (Finland); Front, K.; Pitkaenen, P.; Hassinen, P.; Ylinen, A. [Technical Research Centre of Finland, Espoo (Finland). Road, Traffic and Geotechnical Lab.

    1993-09-01

    Preliminary site investigations implemented in accordance with the research programme drawn up by Teollisuuden Voima Oy (TVO) were carried out at Syyry (in Finland) in 1987-1992. Models of the site were compiled and used for describing the rock types, fracturing, fracture structures and geohydrological conditions, the main emphasis being on the examination of the bedrock fracturing and related hydraulic conductivity. Three-dimensional models were used for the classification of the various properties of the bedrock structures. The descriptive models were gathered into a computer system to facilitate illustration and storage. The main rock type at Syyry is tonalite. A mica gneiss formation SE of the investigation site dips towards the NW and delimits the tonalite as far as the central part of the investigation site. The miga gneiss has a heterogeneous composition and includes intermediate layers consisting of quartz feldspar schist and amphibolite. There are mafic formations in the vicinity of the investigation site. The intrusive rocks have been deformed during three plastic and three mainly brittle deformation stages. (47 refs., 61 figs.).

  18. 10Be chronometry of bedrock-to-soil conversion rates

    Science.gov (United States)

    Monaghan, Marc C.; McKean, James; Dietrich, William; Klein, Jeffrey

    1992-07-01

    We report concentrations of cosmogenic 10Be ( t1/2 = 1.5 × 10 6 yrs) in soil excavated from a soil-mantled hillslope in Black Diamond Mines Regional Park, Contra Costa County, California. The most striking features of the data are: (1) the similarity in the downward decreasing trends of 10Be concentrations in two soil profiles collected 75 m apart, (2) the coincidence in each soil profile of the soil/bedrock interface (as defined by visual inspection of soil pits) and the level at which 10Be concentrations attain very low values ( ˜4 × 10 6 atoms/g), and (3) the extremely low 10Be concentrations in the underlying regolith (0.5 × 10 6 atoms/gram). The inventory of 10Be in these soils is low, equivalent to about 6000 yrs of 10Be accumulation in a soil initially containing no 10Be. On the basis of these measurements, and with the aid of simple models of soil ( 10Be) motions on the hillslope, we conclude that 10Be loss from the surface is dominated by its removal in soil by creep. We calculate local rates of bedrock-to-soil conversion of between 0.15 and 0.27 km/10 6 yrs. Comparing these with uplift rates determined for coastal regions of California indicates that soil creep alone is capable of removing soil from the local geomorphic system at a rate equivalent to the rate of uplift of much of the coast.

  19. Combining airborne electromagnetic and geotechnical data for automated depth to bedrock tracking

    OpenAIRE

    Christensen, Craig; Pfaffhuber, Andreas Aspmo; Anschütz, Helgard; Smaavik, Tone Fallan

    2015-01-01

    Airborne electromagnetic (AEM) survey data was used to supplement geotechnical investigations for a highway construction project in Norway. Heterogeneous geology throughout the survey and consequent variable bedrock threshold resistivity hindered efforts to directly track depth to bedrock, motivating us to develop an automated algorithm to extract depth to bedrock by combining both boreholes and AEM data. We developed two variations of this algorithm: one using simple Gaussian or inverse dist...

  20. Uranium and thorium distribution in soils and weathered bedrock in south Texas

    Science.gov (United States)

    Dickinson, Kendell A.

    1977-01-01

    The distribution of uranium and thorium in soils and weathered bedrock in areas of calich soil development on various kinds of sedimentary bedrock in south Texas indicates that uranium and thorium are leached from the surface layers and deposited deeper in the soil or weathered bedrock. The data provide field evidence that uranium is mobilized during dry-climate weathering, and suggest that caution be used in the interpretation of airborne, radioactive surveys that measure uranium at the surface.

  1. Estimate of dynamic stiffness and damping by forced excitation test of foundation on bedrock. Pt. 2

    International Nuclear Information System (INIS)

    Based on the results of forced excitation tests of foundations on bedrock, dynamic complex stiffness (dynamic stiffness and damping) were obtained at many nuclear power plant sites. Experimental results were investigated by three-dimensional wave propagation theory considering layered stratum of bedrock. It is shown dynamic stiffness can be estimated with sufficient accuracy by considering layered stratum of bedrock. Also it is shown that by two-layered ground model estimate of damping characteristics is possible for foundations on multi-layered bedrock. (orig./HP)

  2. Suitability of seismic investigations for detailed characterisation of Olkiluoto bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Sireni, S. (ed.) [Posiva Oy, Helsinki (Finland); Ahokas, T. [Poeyry Finland Oy, Vantaa (Finland); Paananen, M. [Geological Survey of Finland, Espoo (Finland)

    2011-12-15

    Posiva has carried out two projects of reflection seismic surveys in the underground research facility ONKALO. The surveys contribute the detailed characterization of the bedrock in the final disposal of nuclear fuel. The aim of this work is to gather the results of these surveys and make conclusions of suitability of seismic investigations for detailed characterization of Olkiluoto bedrock. In 2007, the survey was conducted on the wall of the access tunnel at approximately -170 m depth (tunnel length from 1720 m to 1820 m). Target was to develop the field acquisition and processing techniques, and to demonstrate the method's capability to detect fractured zones and large fractures in different positions. The seismic source used was the Vibsist-20, and receivers used were 2-component geophones. Digital seismograph had 100 channels. The reflection data were processed as a standard 2D seismic line. In 2009, the survey line was over 240 m long at a depth of about -350 m (tunnel length from 3325 m to 3585 m). The seismic source used was the Vibsist-250, and receivers were 3-component geophones. Seismograph had 240 channels. 3D Image Point migration (Cosma et al. 2010) algorithms were used to create 3D oriented migrated sections. The 2007 survey concluded that it is feasible to carry out seismic surveying in the tunnels, specifically with 3D-geophones, longer measuring profile, and application of a few more source positions. According to the comparison of the seismic data with known geological, geophysical and hydrological features observed in the tunnel, seismic techniques are able to locate features from site scale (e.g. brittle fault zones) to tunnel scale (e.g. tunnel crosscutting fractures). The results also correlated with hydraulically conductive zones. Reflectors of the 2009 survey data were digitized and triangulated to digital terrain models. Interpretation was made by correlating the reflectors with known geological, geophysical and hydrological features

  3. Suitability of seismic investigations for detailed characterisation of Olkiluoto bedrock

    International Nuclear Information System (INIS)

    Posiva has carried out two projects of reflection seismic surveys in the underground research facility ONKALO. The surveys contribute the detailed characterization of the bedrock in the final disposal of nuclear fuel. The aim of this work is to gather the results of these surveys and make conclusions of suitability of seismic investigations for detailed characterization of Olkiluoto bedrock. In 2007, the survey was conducted on the wall of the access tunnel at approximately -170 m depth (tunnel length from 1720 m to 1820 m). Target was to develop the field acquisition and processing techniques, and to demonstrate the method's capability to detect fractured zones and large fractures in different positions. The seismic source used was the Vibsist-20, and receivers used were 2-component geophones. Digital seismograph had 100 channels. The reflection data were processed as a standard 2D seismic line. In 2009, the survey line was over 240 m long at a depth of about -350 m (tunnel length from 3325 m to 3585 m). The seismic source used was the Vibsist-250, and receivers were 3-component geophones. Seismograph had 240 channels. 3D Image Point migration (Cosma et al. 2010) algorithms were used to create 3D oriented migrated sections. The 2007 survey concluded that it is feasible to carry out seismic surveying in the tunnels, specifically with 3D-geophones, longer measuring profile, and application of a few more source positions. According to the comparison of the seismic data with known geological, geophysical and hydrological features observed in the tunnel, seismic techniques are able to locate features from site scale (e.g. brittle fault zones) to tunnel scale (e.g. tunnel crosscutting fractures). The results also correlated with hydraulically conductive zones. Reflectors of the 2009 survey data were digitized and triangulated to digital terrain models. Interpretation was made by correlating the reflectors with known geological, geophysical and hydrological features

  4. 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

  5. Shallow reflection seismic soundings in bedrock at Lavia

    International Nuclear Information System (INIS)

    The well-studied granitic block at Lavia was one of the test sites of a shallow seismic development project. A portable digital seismograph and high frequency geophones were rented fro the field period. A sledge hamme and a drop weight were tested as wave sources. The sounding was carried out on outcropped area in order to record high frequency reflections from known subhorizontal fracture zones as shallow as 30 m. Large amplitude surface waves hide most of the shallow reflections, recognizable only on few traces in the data. The data processing carried out did not reveal the geometry of these reflectors. Events arriving after the ground roll were analyzed in 2-folded CDP-sections. The continuous reflective horizons in them correspond to lithological changes and fracture zones located deeper than 200 m in the bedrock

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

    International Nuclear Information System (INIS)

    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

  7. Hydrogeology - AQUIFERS_BEDROCK_USGS_IN: Bedrock Aquifer Systems in Indiana (United States Geological Survey, 1:500,000, Polygon Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Four types of bedrock aquifers in 12 water-management basins identified by the Indiana Natural Resources Commission (INRC) in Indiana were identified by the USGS in...

  8. Fluorine geochemistry in bedrock groundwater of South Korea.

    Science.gov (United States)

    Chae, Gi-Tak; Yun, Seong-Taek; Mayer, Bernhard; Kim, Kyoung-Ho; Kim, Seong-Yong; Kwon, Jang-Soon; Kim, Kangjoo; Koh, Yong-Kwon

    2007-10-15

    High fluoride concentrations (median=4.4 mg/L) in deep bedrock groundwater of South Korea prevent the usage of it as a drinking water source. The hydrogeochemistry of deep thermal groundwaters (N=377) in diverse bedrocks has been studied in order to evaluate the geologic and geochemical controls on fluoride concentrations in groundwater. The groundwater samples were clustered geologically, and the average and median concentrations of fluoride were compared by the Mann-Whitney U test. The order of median fluoride concentration with respect to geology is as follows: metamorphic rocks> or =granitoids > or =complex rock>volcanic rocks> or =sedimentary rocks. This result indicates that the geological source of fluoride in groundwater is related to the mineral composition of metamorphic rocks and granitoids. With respect to groundwater chemistry, the fluoride concentration was highest in Na-HCO3 type groundwater and lowest in Ca-HCO3 type groundwater. Ionic relationships also imply that the geochemical behavior of fluoride in groundwater is related to the geochemical process releasing Na and removing Ca ions. The thermodynamic relationship between the activities of Ca and F indicates that fluoride concentration is controlled by the equilibrium of fluorite (CaF2). In other words, the upper limits of fluoride concentration are determined by the Ca ion; i.e., Ca concentrations play a crucial role in fluoride behavior in deep thermal groundwater. The result of this study suggests that the high fluoride in groundwater originates from geological sources and fluoride can be removed by fluorite precipitation when high Ca concentration is maintained. This provides a basis for a proper management plan to develop the deep thermal groundwater and for treatment of high fluoride groundwater frequently found in South Korea. PMID:17655916

  9. On the reliability of manually produced bedrock lineament maps

    Science.gov (United States)

    Scheiber, Thomas; Viola, Giulio; Fredin, Ola; Jarna, Alexandra; Gasser, Deta; Łapinska-Viola, Renata

    2016-04-01

    Manual extraction of topographic features from digital elevation models (DEMs) is a commonly used technique to produce lineament maps of fractured basement areas. There are, however, several sources of bias which can influence the results. In this study we investigated the influence of the factors (a) scale, (b) illumination azimuth and (c) operator on remote sensing results by using a LiDAR (Light Detection and Ranging) DEM of a fractured bedrock terrain located in SW Norway. Six operators with different backgrounds in Earth sciences and remote sensing techniques mapped the same LiDAR DEM at three different scales and illuminated from three different directions. This resulted in a total of 54 lineament maps which were compared on the basis of number, length and orientation of the drawn lineaments. The maps show considerable output variability depending on the three investigated factors. In detail: (1) at larger scales, the number of lineaments drawn increases, the line lengths generally decrease, and the orientation variability increases; (2) Linear features oriented perpendicular to the source of illumination are preferentially enhanced; (3) The reproducibility among the different operators is generally poor. Each operator has a personal mapping style and his/her own perception of what is a lineament. Consequently, we question the reliability of manually produced bedrock lineament maps drawn by one person only and suggest the following approach: In every lineament mapping study it is important to define clear mapping goals and design the project accordingly. Care should be taken to find the appropriate mapping scale and to establish the ideal illumination azimuths so that important trends are not underrepresented. In a remote sensing project with several persons included, an agreement should be reached on a given common view on the data, which can be achieved by the mapping of a small test area. The operators should be aware of the human perception bias. Finally

  10. Ultramafic-derived arsenic in a fractured bedrock aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, Peter C., E-mail: pryan@middlebury.edu [Geology Department, Middlebury College, 276 Bicentennial Way, Middlebury, VT 05753 (United States); Kim, Jonathan [Vermont Geological Survey, Waterbury, VT 05671 (United States); Wall, Andrew J. [Department of Geosciences, Penn State University, University Park, PA 16802 (United States); Moen, Jonathan C.; Corenthal, Lilly G.; Chow, Daniel R.; Sullivan, Colleen M.; Bright, Kevin S. [Geology Department, Middlebury College, 276 Bicentennial Way, Middlebury, VT 05753 (United States)

    2011-04-15

    Highlights: > Arsenic is elevated in groundwater from a fractured bedrock aquifer system in northern Vermont, USA. > The arsenic source is serpentinized ultramafic rock. > Antigorite, magnetite (MgCO{sub 3}) and magnetite (Fe{sub 3}O{sub 4}) appear to be the main mineralogical hosts of arsenic in the ultramafic rock. > Arsenic appears to be introduced to the ultramafic rock when As-bearing fluids are driven out of sediments during subduction. >. > The occurrence of serpentinized ultramafic rocks in many orogenic belts suggests that similar arsenic anomalies may occur in geologically-similar terranes globally. - Abstract: In the fractured bedrock aquifer of northern Vermont, USA, As concentrations in groundwater range from <1 to 327 {mu}g/L (<13-4360 nm/L) and these elevated occurrences have a general spatial association with ultramafic rock bodies. The ultramafic rocks in this region are comprised mainly of serpentinites and talc-magnesite rocks with average As concentration of 93 ppm and a range from 1 to 1105 ppm. By comparison, the other main lithologies in the study area are depleted in As relative to the ultramafics: the average As concentration in metabasaltic rocks is 4.1 ppm with a range of <1-69 ppm, and mean As concentration in meta-sedimentary phyllites and schists is 22 ppm with a range of <1-190 ppm. In the ultramafic rocks, As is correlated with Sb and light rare earth elements, indicating that As was introduced to the ultramafic rocks during metasomatism by fluids derived from the subducting slab. Evidence from sequential chemical extraction, X-ray diffraction (XRD) and stoichiometric analysis indicates that the majority of the As is located in antigorite and magnesite (MgCO{sub 3}) with lesser amounts in magnetite (Fe{sub 3}O{sub 4}). Hydrochemistry of monitoring wells drilled into fractured ultramafic rock in a groundwater recharge area with no anthropogenic As source reveals above background As (2-9 {mu}g/L) and an Mg-HCO{sub 3} hydrochemical

  11. 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...

  12. Vegetation and wildfire controls on sediment yield in bedrock landscapes

    Science.gov (United States)

    Dibiase, Roman A.; Lamb, Michael P.

    2013-03-01

    rocky landscapes commonly exhibit high sediment yields and are especially sensitive to climate, tectonics, and wildfire. Predicting landscape response to these perturbations demands a quantitative understanding of erosion processes. However, existing models for hillslope sediment production and transport do not apply to landscapes with patchy soil and slopes that exceed the angle for sediment stability. Here we present field measurements in southern California, USA, which indicate that sediment storage on steep slopes is enabled by vegetation that traps sediment upslope. We find that the storage capacity of unburned vegetation dams follows a geometric scaling model with a cubic dependence on effective plant width and an inverse dependence on local slope. Measured sediment volumes behind burned vegetation dams indicate a loss of at least 75% relative to unburned dams, and when expanded to the catchment scale, our measurements match records of postfire sediment yield from nearby retention basins. Contrary to existing models, our observations indicate that wildfire-induced sediment yield is driven by transient storage and release of sediment by vegetation dams, rather than increased bedrock-to-soil conversion rates. Without a feedback between soil production and wildfire, fire may play little role in long-term landscape evolution, and increasing fire frequency in response to climate change may not result in heightened sedimentation hazards due to supply limitations.

  13. Radioelement (U,Th,Rn) concentrations in Norwegian bedrock groundwaters

    International Nuclear Information System (INIS)

    Samples of groundwater from bedrock boreholes in three Norwegian geological provinces have been analysed for content of 222Rn, U and Th. Median values of 290 Bq/l, 7.6 μg/l and 0.02 μg/l were obtained for Rn, U and Th, respectively, while maximum values were 8500 Bq/l, 170 μg/l and 2.2 μg/l. Commonly suggested drinking water limits range from 8 to 1000 Bq/l for radon and 14 to 160 μg/l for uranium. Radioelement content was closely related to lithology, the lowest concentrations being derived from the largely Caledonian rocks of the Troendelag area, and the highest from the Precambrian Iddefjord Granite of South East Norway where median values of 2500 Bq/l, 15 μg/l and 0.38 μg/l, respectively, were obtained. The Iddefjord Granite is not believed to be unique in Norway yielding high dissolved radionuclide contents in groundwaters, and several other granitic aquifers warrant further investigation in this respect. 63 refs., 13 figs., 8 tabs

  14. Final disposal of spent fuel in the Finnish bedrock

    International Nuclear Information System (INIS)

    Teollisuuden Voima Oy (TVO) is preparing for the final disposal of spent nuclear fuel from the Olkiluoto nuclear power plant (TVO-I and TVO-II reactors). According to present estimates, a total of 1840 tU of spent fuel will be accumulated during the 40-year lifetime of the power plant. An interim storage facility for spent fuel (TVO-KPA Store) has operated at Olkiluoto since 1987. The spent fuel will be held in storage for several decades before it is shipped to the repository site. Both train and road transportation are possible. The spent fuel will be encapsulated in composite copper and steel canisters (ACP Canister) in a facility that will be build above the ground on the site where the repository is located. The repository will be constructed at the depth of several hundreds of meters in the bedrock. In 1987 five areas were selected for preliminary site investigations. The safety analysis (TVO-92) that was carried out shows that the proposed safety criteria would be met at each of the candidate sites. In future expected conditions there would never be significant releases of radioactive substances to the biosphere. The site investigations will be continued in the period 1993 to 2000. In parallel, a R and D programme will be devoted to the safety and technology of final disposal. The site for final disposal will be selected in the year 2000 with the aim of having the capability to start the disposal operations in 2020

  15. Finite Amplitude Bars in Mixed Bedrock-Alluvial River Channel Bends

    Science.gov (United States)

    Nelson, P. A.; Seminara, G.; Bolla Pittaluga, M.

    2012-12-01

    A common and well-understood feature of alluvial rivers is the tendency for channel curvature to induce bed deformations, producing a point bar on the inner bank and scour on the outer bank. However, for mixed bedrock-alluvial rivers, where the amount of sediment supplied from upstream is less than the local sediment transport capacity, our understanding of this phenomenon is less clear. Our goal here is to develop a theory capable of answering the question: How does channel curvature influence sediment deposition and bedrock exposure in mixed bedrock-alluvial rivers? We have developed a nonlinear asymptotic theory of fully developed flow and bed topography in a wide channel of constant curvature to describe finite-amplitude perturbations of bottom topography, subject to an inerodible bedrock layer. The flow field is evaluated at leading order of approximation as a slowly varying sequence of locally uniform flows, slightly perturbed by a weak curvature-induced secondary flow. Using the constraint of constant fluid discharge, we calculate an analytical solution for the cross-sectional profile of flow depth and bed topography, and we determine the average slope in the bend necessary to transport the sediment supplied from a straight, alluvial, upstream reach. Both fully-alluvial bends and bends with partial bedrock exposure are shown to require a larger average slope than a straight upstream reach; the relative slope increase is much larger for partially alluviated bends. Curvature has a strong effect on the characteristics of the point bars in mixed bedrock-alluvial channels, with higher curvature bends exhibiting bars of larger amplitude and more bedrock exposure through the cross section. Differences in the relative roughness of sediment and bedrock have a smaller, secondary effect on point bar characteristics. This theory can potentially be extended to the not fully developed case, and should ultimately lead to an improved understanding of the formation of

  16. Quality of bedrock groundwater in western Finland, with special reference to nitrogen compounds

    Directory of Open Access Journals (Sweden)

    Karro, E.

    1999-12-01

    Full Text Available Monitoring of bedrock aquifers utilized for water supply in the Vaasa region, western Finland, suggests slight changes in the chemical composition of groundwater resulting both from natural and anthropogenic factors. Applying the permissible limits for parameters in drinking water reveals that the groundwater quality is generally good. Groundwater occurring in fractures and fissures of the crystalline bedrock is protected from anthropogenic pollution by clay and till deposits with low permeability. Temporally, the contents of nitrogen compounds in groundwater exhibit a decreasing trend. Reducing conditions prevailing in bedrock aquifers are reflected in elevated ammonium, iron and manganese contents in water.

  17. Bedrock geology of the Mount Carmel and Southington quadrangles, Connecticut

    Science.gov (United States)

    Fritts, Crawford Ellswroth

    1962-01-01

    New data concerning the geologic structure, stratigraphy, petrography, origin, and ages of bedrock formations in an area of approximately 111 square miles in south-central Connecticut were obtained in the course of detailed geologic mapping from 1957 to 1960. Mapping was done at a scale of 1:24,000 on topographic base maps having a 10-foot contour interval. Bedrock formations are classified in two principal categories. The first includes metasedimentary, meta-igneous, and igneous rocks of Precambrian to Devonian age, which crop out in the western parts of both quadrangles. The second includes sedimentary and igneous rocks of the Newark Group of Late Triassic age, which crop out in the eastern parts of the quadrangles. Diabase dikes, which are Late Triassic or younger in age, intruded rocks in both the western and eastern parts of the map area. Rocks in the western part of the area underwent progressive regional metamorphism in Middle to Late Devonian time. The arrangement of the chlorite, garnet, biotite, staurolite, and kyanite zones here is approximately the mirror-image of metamorphic zones in Dutchess County, New York. However, garnet appeared before biotite in politic rocks in the map area, because the ration MgO/FeO is low. Waterbury Gneiss and the intrusive Woodtick Gneiss are parts of a basement complex of Precambrian age, which forms the core of the Waterbury dome. This structure is near the southern end of a line of similar domes that lie along the crest of a geanticline east of the Green Mountain anticlinorium. The Waterbury Gneiss is believed to have been metamorphosed in Precambrian time as well as in Paleozoic time. The Woodtick Gneiss also may have been metamorphosed more than once. In Paleozoic time, sediments were deposited in geosynclines during two main cycles of sedimentation. The Straits, Southington Mountain, and Derby Hill Schists, which range in age from Cambrian to Ordovician, reflect a transition from relatively clean politic sediments to

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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 (Al2O3) 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

  20. 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.

  1. Bedrock geology of the Arabian Peninsula and selected adjacent areas (geo2bg)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The data set for this coverage includes arcs, polygons, and polygon labels that outline and describe the general geologic age and type of bedrock of the Arabian...

  2. Bedrock Geology of the turkey Creek Drainage Basin, Jefferson County, Colorado

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This geospatial data set describes bedrock geology of the Turkey Creek drainage basin in Jefferson County, Colorado. It was digitized from maps of fault locations...

  3. Bedrock Data from Western Cape Cod, Massachusetts (WELLSITE shapefile, Geographic, NAD27)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Cores collected from recent drilling in western Cape Cod, Massachusetts provide insight into the topography and petrology of the underlying bedrock. Cores from 64...

  4. Lithogeochemical Character of Near-Surface Bedrock in the Connecticut, Housatonic and Thames River Basins

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data layer shows the generalized lithologic and geochemical (lithogeochemical) character of near-surface bedrock in the Connecticut, Housatonic, and Thames...

  5. Measured and Inferred Bedrock Faults in the Boulder-Weld Coal Field (frifaultu)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This file is a digital line representation of measured and inferred bedrock faults in the Boulder-Weld coal field, Denver Basin, Colorado. This file was created as...

  6. Lithogeochemical Character of Near-Surface Bedrock in the New England Coastal Basins

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This geographic information system (GIS) data layer shows the generalized lithologic and geochemical, termed lithogeochemical, character of near-surface bedrock in...

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

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — 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...

  8. 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

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

    OpenAIRE

    Ramstad, Randi Kalskin

    2004-01-01

    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 ...

  10. Uncertainty in rock properties: Implications for analysis of radionuclide migration in heterogeneous bedrock

    International Nuclear Information System (INIS)

    A basic rationale for the current study is that site investigations in connection with the planning of the final repository for high radioactive waste will provide only fragmentary (discrete) information of the bedrock properties. Since the bedrock displays generally a significant heterogeneity in most properties of relevance to radionuclide migration, there will be uncertainties about the barrier effect provided by the bedrock towards accidental leakage of radionuclides from the repository. This paper shows how the heterogeneity in the bedrock properties has two fundamentally different implications for an analysis of radionuclide transport. First, the actual variation of bedrock properties causes migrating nuclides to encounter a certain (known) distribution of properties along their transport path. The associated effect does not depend on the spatial correlation of properties (auto-covariance), but does depend on the variance and cross-correlation between the properties. A second effect is due to the uncertainty about the statistical representativity of properties along an individual transport path, which is related to the discrete measuring technique. This effect can, generally, be considered to be the main effect of the heterogeneity of the bedrock on analysis of solute transport. By analysis of an ensemble of equally probable realisations of the transport along an individual path we were able to express the expected values of the mean and variance of the residence time PDF for radionuclides travelling in a single fracture. The 'uncertainty effect' is significant if a certain sum of H-terms is much larger than unity. Based on geostatistical information for the Swedish granitic bedrock, the effect of uncertainty of bedrock properties on the transport of radionuclides can be important for fractures thinner than about 0.1 mm. The geostatistical information was obtained through sampling drill-cores at the Aespoe Hard Rock Laboratory and performing a large number of

  11. Fractured bedrock investigation by using high-resolution borehole images and the Distributed Temperature Sensing technique

    OpenAIRE

    Radioti, Georgia; Delvoie, Simon; Radu, Jean-Pol; Nguyen, Frédéric; Charlier, Robert

    2015-01-01

    In order to investigate the fracturing of the bedrock and its possible heterogeneous distribution in situ, four boreholes equipped with double-U geothermal pipes of 100 m long were installed on the campus of the University of Liege (Liege, Belgium) over a surface area of 32 m². The bedrock, which starts at a depth approximately of 8 m, is quite fractured and consists mainly of siltstone and shale interbedded with sandstone. Different geophysical methods are applied at two different phas...

  12. Permafrost in steep bedrock slopes and its temperature-related destabilization following climate change

    OpenAIRE

    Gruber, S.; Haeberli, W.

    2007-01-01

    Permafrost in steep bedrock is abundant in many cold-mountain areas, and its degradation can cause slope instability that is unexpected and unprecedented in location, magnitude, frequency, and timing. These phenomena bear consequences for the understanding of landscape evolution, natural hazards, and the safe and sustainable operation of high-mountain infrastructure. Permafrost in steep bedrock is an emerging field of research. Knowledge of rock temperatures, ice content, mechanisms of de...

  13. Bedrock mapping of buried valley networks using seismic reflection and airborne electromagnetic data

    Science.gov (United States)

    Oldenborger, G. A.; Logan, C. E.; Hinton, M. J.; Pugin, A. J.-M.; Sapia, V.; Sharpe, D. R.; Russell, H. A. J.

    2016-05-01

    In glaciated terrain, buried valleys often host aquifers that are significant groundwater resources. However, given the range of scales, spatial complexity and depth of burial, buried valleys often remain undetected or insufficiently mapped. Accurate and thorough mapping of bedrock topography is a crucial step in detecting and delineating buried valleys and understanding formative valley processes. We develop a bedrock mapping procedure supported by the combination of seismic reflection data and helicopter time-domain electromagnetic data with water well records for the Spiritwood buried valley aquifer system in Manitoba, Canada. The limited spatial density of water well bedrock observations precludes complete depiction of the buried valley bedrock topography and renders the water well records alone inadequate for accurate hydrogeological model building. Instead, we leverage the complementary strengths of seismic reflection and airborne electromagnetic data for accurate local detection of the sediment-bedrock interface and for spatially extensive coverage, respectively. Seismic reflection data are used to define buried valley morphology in cross-section beneath survey lines distributed over a regional area. A 3D model of electrical conductivity is derived from inversion of the airborne electromagnetic data and used to extrapolate buried valley morphology over the entire survey area. A spatially variable assignment of the electrical conductivity at the bedrock surface is applied to different features of the buried valley morphology identified in the seismic cross-sections. Electrical conductivity is then used to guide construction of buried valley shapes between seismic sections. The 3D locus of points defining each morphological valley feature is constructed using a path optimization routine that utilizes deviation from the assigned electrical conductivities as the cost function. Our resulting map represents a bedrock surface of unprecedented detail with more

  14. Quality of bedrock groundwater in western Finland, with special reference to nitrogen compounds

    OpenAIRE

    Karro, E.

    1999-01-01

    Monitoring of bedrock aquifers utilized for water supply in the Vaasa region, western Finland, suggests slight changes in the chemical composition of groundwater resulting both from natural and anthropogenic factors. Applying the permissible limits for parameters in drinking water reveals that the groundwater quality is generally good. Groundwater occurring in fractures and fissures of the crystalline bedrock is protected from anthropogenic pollution by clay and till deposits with low permeab...

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

    OpenAIRE

    Ramstad, Randi Kalskin

    2004-01-01

    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 o...

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

    OpenAIRE

    Raposo, J. R.; Molinero, J.; Dafonte, J.

    2012-01-01

    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 presen...

  17. 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.

  18. Combining airborne electromagnetic and geotechnical data for automated depth to bedrock tracking

    Science.gov (United States)

    Christensen, Craig William; Pfaffhuber, Andreas Aspmo; Anschütz, Helgard; Smaavik, Tone Fallan

    2015-08-01

    Airborne electromagnetic (AEM) survey data was used to supplement geotechnical investigations for a highway construction project in Norway. Heterogeneous geology throughout the survey and consequent variable bedrock threshold resistivity hindered efforts to directly track depth to bedrock, motivating us to develop an automated algorithm to extract depth to bedrock by combining both boreholes and AEM data. We developed two variations of this algorithm: one using simple Gaussian or inverse distance weighting interpolators, and another using ordinary kriging and combined probability distribution functions of input parameters. Evaluation shows that for preliminary surveys, significant savings in boreholes required can be made without sacrificing bedrock model accuracy. In the case study presented, we estimate data collection savings of 1000 to 10,000 NOK/km (c. 160 to 1600 USD/km) would have been possible for early phases of the investigation. However, issues with anthropogenic noise, low signal, and uncertainties in the inversion model likely reduced the comparative advantage that including AEM provided. AEM cannot supersede direct sampling where the model accuracy required exceed the resolution possible with the geophysical measurements. Nevertheless, with the algorithm we can identify high probability zones for shallow bedrock, identify steep or anomalous bedrock topography, and estimate the spatial variability of depth at earlier phases of investigation. Thus, we assert that our method is still useful where detailed mapping is the goal because it allows for more efficient planning of secondary phases of drilling.

  19. Effects of bedrock groundwater on landslide occurrences in a steep headwater catchment

    Science.gov (United States)

    Kosugi, K.; Fujimoto, M.; Sando, Y.; Mizuyama, T.; Kinoshita, A.

    2011-12-01

    Previous studies have shown that the formation of groundwater in the soil mantle greatly affects slope instability on steep landscapes. To predict landslides, mathematical models based on a geographic information system, which organize geographic data such as information on upslope contributing areas and the local slope gradient, have been developed and tested. Although such models can be used to calculate the topographically driven convergence of rainwater and groundwater table developments in the soil mantle, thus providing a spatially distributed prediction of landslide occurrences, the accuracy of these mathematical models is still limited, mainly because they ignore storm responses in underlying bedrock. Recent research has provided credible information on the importance of bedrock groundwater on surface hydrological processes in headwater catchments. To elucidate the effects of bedrock groundwater, the dynamics of bedrock groundwater should be measured directly. However, intensive monitoring of bedrock groundwater is rare in mountains with steep topography. Consequently, how bedrock groundwater controls landslides in a steep headwater catchment is in dispute. In this study, we conducted long-term hydrological observations using densely nested bedrock wells along with monitoring of discharge hydrograph and soil mantle groundwater in a steep headwater catchment underlain by granitic bedrock. Bedrock wells with depths of 7-78 m were drilled at 31 points within the 2.10-ha catchment. Results showed that a hollow of bedrock aquifer was located at a ridge in the surface topography, clearly indicating bedrock groundwater flow across topographic divides. Around a point where the bedrock groundwater exfiltrated, we found scars of landslides. Such landslides cannot be explained by mathematical hydrology models, which calculate the topographically driven convergence of rainwater in the soil mantle. Moreover, at a point along the main hollow of the watershed, we observed

  20. Present-day mass changes for the Greenland ice sheet and their interaction with bedrock adjustment

    Directory of Open Access Journals (Sweden)

    M. Olaizola

    2011-12-01

    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 estimates, data need to be corrected for the effect of deformation changes of the Earth's crust. This is usually done by independently modeling the Glaciological Isostatic Adjustment (GIA trend and then by removing it from the data. Recently, Wu et al. (2010 proposed a new method to simultaneously estimate GIA and the present-day ice mass change, reporting an ice mass loss of around half of the previously published estimates and a general bedrock subsidence concentrated in the central parts of Greenland. This subsidence appears to be counterintuitive since the ice sheet is loosing mass at present. It was suggested by the authors that this could be a new evidence for additional net past ice accumulation.

    In this study, a 3-D ice-sheet model with a surface mass balance forcing based on a mass balance gradient approach has been used to: (a analyze the bedrock response to changes in the ice load in order to evaluate whether bedrock subsidence and ice thinning can exist simultaneously; (b study the magnitude and the pattern of the bedrock movement; and (c evaluate if present-day bedrock subsidence could be the result of a net past mass accumulation.

    Under a sine forcing of the annual temperature, that mimics the temperature variations in the Holocene, mass changes yield a delay of the bedrock response of 200 years. Thinning of the ice as well as bedrock subsidence coexist during this period with an order of magnitude equal to the observations by Wu et al. (2010. Although, the resulting pattern of bedrock changes differs considerable: instead of the general bedrock subsidence reported before, we found areas of bedrock uplift as well as areas of bedrock subsidence. A simulation since the last glacial maximum (with the

  1. Radiological risks due to intrusion into a deep bedrock repository

    International Nuclear Information System (INIS)

    The Swedish concept for disposal of high-level waste is a deep (500 m) bedrock repository (SFL) protected by multiple barriers that isolate the waste from the environment for such a long time that the physical decay will cause a substantial reduction of the radioactivity. The aim of concentration and isolation of high-level waste is to reduce the radiation risk. Intrusion in the repository may introduce a small residual risk to individuals. A risk analysis was performed comprising dose assessment and probabilities of occurrence. Intrusions may be considered to take place either due to conscious actions or by actions without any knowledge about the repository. For conscious intrusion it may be assumed that there will be enough knowledge to manage the radiation situation in a professional manner. Several reasons for making inadvertent intrusion are possible. Independently of the purpose, the most probable initial way of coming into contact with the radioactive material is by deep drilling. Examples of causes for drilling could be general scientific purposes or exploitation of geothermal energy. Dose assessments were made for intrusion due to inclined drilling directly into a canister, and drilling near an initially malfunctioning canister from which radionuclides have leaked into the groundwater. For the former case, external pathways were considered due to exposure from a core of the canister with fuel and contaminated bore dust. The most common drilling method is with water flushing for removal of bore dust, which will not cause any substantial transfer of radionuclides to air. For the second case, it was assumed that there was a well in the vicinity. The only pathway considered was therefore consumption of water because it dominates the exposure. The highest dose rates to man were, as expected, obtained by drilling into the canister. Dose rates decrease with time after closure. During the first time the relatively short-lived radionuclides Cs-137 and Sr-90 give

  2. 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.

  3. Bedform genesis and evolution in bedrock substrates: a new experimental approach

    Science.gov (United States)

    Parsons, D. R.; Yin, N.; Peakall, J.

    2014-12-01

    Most previous studies on the genesis and evolution of bedforms have focused on aggradational bedforms within cohesionless sediments, with very few investigations that concern either erosive bedform genesis and evolution or bedrock channel abrasion processes. The study presented here details experiments that involve the genesis and formation of erosional bedform features within natural (soft clay) cohesive sediment beds and analogue bedrock substrates by modelling clay under the effect of both open-channel plain water flows, and sediment-laden flows. A new approach without using plaster-of-Paris or real bedrock developed provides a feasible method to simulate the genesis and evolution of the erosional bedforms in cohesive sediment beds and sculpted forms in bedrock channels on relatively short time-scales in the laboratory by using a realistic substrate substitute.A series of flume experiments are presented herein where the undrained shear strength of two different kinds of substrate material is systematically varied under constant flow conditions. Experiments using plain water flow indicated that erosive bedforms in cohesive sediment substrate cannot be produced only under the effect of sediment-free flow. Particulate-laden flows do form erosional bedforms in both kinds of clay beds and the shear strength of the bed material plays a key role in determining the diversity of erosional features forming on such substrates. Optimisation of modelling clay beds has enabled us to successfully replicate a suite of bedrock bedforms, including potholes, flutes, longitudinal furrows, etc., that have clear equivalents to those observed in bedrock rivers and contributed to investigate the genesis and evolution process of them and explore the flow structures within and above them in experimental analogue bedrock substrate for the first time.

  4. Three dimensional characterization and capture zone analysis of a dipping tabular fractured bedrock aquifer

    International Nuclear Information System (INIS)

    In order to improve the effectiveness of an existing groundwater recovery and treatment system at a manufacturing site in eastern Pennsylvania, an analysis of groundwater flow within fractured bedrock of the Triassic Brunswick Formation was conducted using water quality, lithologic and hydrologic data, compiled at the site over a period of 13 years. Groundwater quality data, collected from on-site monitoring wells and offsite wells, indicate that a plume of dissolved phase volatile organic compounds originates on the site and has migrated off-site. Groundwater pumping test data from different areas of the site and from three discrete bedrock zones, as well as, the performance of the existing groundwater treatment system indicate: the groundwater system in the bedrock at the site can be conceptualized as a series of tabular aquifers (brittle fractured beds) separated by finer grained, more ductile aquitards which control flow between aquifers. The hydrologic units within the site bedrock have the same orientation as the geologic beds at the site. The development of groundwater flow maps, corrected for anisotropy, which utilize the cone of depression from the existing recovery well, coupled with the geohydrologic model of the site, allowed the development of a modified multiple well groundwater recovery system which will provide control of groundwater sufficient to capture the on-site contamination. The findings of the study demonstrate that the understanding of the geology of the bedrock aquifer and the hydrologic properties of the different geologic units at the site was critical to the design of an effective groundwater recovery system which considers both the anisotropy of the bedrock and the presence of aquitards within the bedrock

  5. Carbon and nitrogen dynamics across a bedrock-regulated subarctic pH gradient

    Science.gov (United States)

    Tomczyk, N.; Heim, E. W.; Sadowsky, J.; Remiszewski, K.; Varner, R. K.; Bryce, J. G.; Frey, S. D.

    2014-12-01

    Bedrock geochemistry has been shown to influence landscape evolution due to nutrient limitation on primary production. There may also be less direct interactions between bedrock-derived chemicals and ecosystem function. Effects of calcium (Ca) and pH on soil carbon (C) and nitrogen (N) cycling have been shown in acid impacted forests o f North America. Understanding intrinsic factors that affect C and nutrient dynamics in subarctic ecosystems has implications for how these ecosystems will respond to a changing climate. How the soil microbial community allocates enzymes to acquire resources from the environment can indicate whether a system is nutrient or energy limited. This study examined whether bedrock geochemistry exerts pressure on nutrient cycles in the overlying soils. In thin, weakly developed soils, bedrock is the primary mineral material and is a source of vital nutrients. Nitrogen (N) and C are not derived from bedrock, but their cycling is still affected by reactions with geologically-derived chemicals. Our study sites near Abisko, Sweden (~68°N) were selected adjacent to five distinct bedrock outcrops (quartzite, slate, carbonate, and two different metasedimenty units). All sites were at a similar elevation (~700 m a.s.l.) and had similar vegetation (subarctic heath). Nutrient concentrations in bedrock and soils were measured in addition to soil microbial biomass and extracellular enzyme activity. We found a statistically significant correlation between soil Ca concentrations and soil pH (r = 0.88, p enzyme activity (r = -0.89, p enzyme activity and soil C-to-N ratio (r = 0.78, p < 0.01). These results suggest that soil Ca concentrations influence C and N cycling dynamics in these soils through their effect on soil pH.

  6. Permafrost in steep bedrock slopes and its temperature-related destabilization following climate change

    Science.gov (United States)

    Gruber, S.; Haeberli, W.

    2007-06-01

    Permafrost in steep bedrock is abundant in many cold-mountain areas, and its degradation can cause slope instability that is unexpected and unprecedented in location, magnitude, frequency, and timing. These phenomena bear consequences for the understanding of landscape evolution, natural hazards, and the safe and sustainable operation of high-mountain infrastructure. Permafrost in steep bedrock is an emerging field of research. Knowledge of rock temperatures, ice content, mechanisms of degradation, and the processes that link warming and destabilization is often fragmental. In this article we provide a review and discussion of existing literature and pinpoint important questions. Ice-filled joints are common in bedrock permafrost and possibly actively widened by ice segregation. Broad evidence of destabilization by warming permafrost exists despite problems of attributing individual events to this phenomenon with certainty. Convex topography such as ridges, spurs, and peaks is often subject to faster and deeper thaw than other areas. Permafrost degradation in steep bedrock can be strongly affected by percolating water in fractures. This degradation by advection is difficult to predict and can lead to quick and deep development of thaw corridors along fractures in permafrost and potentially destabilize much greater volumes of rock than conduction would. Although most research on steep bedrock permafrost originates from the Alps, it will likely gain importance in other geographic regions with mountain permafrost.

  7. 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.)

  8. Physically based probability criterion for exceeding radionuclide concentration limits in heterogeneous bedrock

    International Nuclear Information System (INIS)

    A significant problem in a risk analysis of the repository for high-level nuclear waste is to estimate the barrier effect of the geosphere. The significant spatial variability of the rock properties implies that migrating RNs encounter a distribution of bedrock properties and mass-transfer mechanisms in different proportions along the transport paths. For practical reasons, we will never be able to know exactly this distribution of properties by performing a reasonable amount of measurements in a site investigation. On the contrary, recent experimental studies reveal that crystalline bedrock can possess a marked heterogeneity of various physical and geochemical properties that potentially may have a certain impact on the transport of RNs in fractured bedrock. Also current field investigation techniques provide only fragmentary information of the properties of the geosphere. This is a basic motivation for treating flows of water and solute elements in groundwaters by means of stochastic continuum models. The stochastic analysis is based on the idea that we know only certain point values of the property fields and use this information to estimate intermediate values. The probabilistic properties of the stochastic analysis are suitable input variables for risk analyses of the relevant sequence of extreme events for which empirical observations are rare or non-existing. The purpose of this paper is to outline the implications of the stochastic approach for estimating probabilities that certain concentration limits are exceeded at discharge points from. the bedrock in case of a leakage from the waste repository. The analysis is restricted to the water flow and solute transport in the bedrock alone without consideration of the full sequence of events in a full risk analysis and the Bayesian statistics involved in such conditioned (and cross-correlated) event series. The focus is on the implication for the risk analysis of the auto-covariance structure in bedrock

  9. Bedrock topography of western Cape Cod, Massachusetts, based on bedrock altitudes from geologic borings and analysis of ambient seismic noise by the horizontal-to-vertical spectral-ratio method

    Science.gov (United States)

    Fairchild, Gillian M.; Lane, Jr., John W.; Voytek, Emily B.; LeBlanc, Denis R.

    2013-01-01

    This report presents a topographic map of the bedrock surface beneath western Cape Cod, Massachusetts, that was prepared for use in groundwater-flow models of the Sagamore lens of the Cape Cod aquifer. The bedrock surface of western Cape Cod had been characterized previously through seismic refraction surveys and borings drilled to bedrock. The borings were mostly on and near the Massachusetts Military Reservation (MMR). The bedrock surface was first mapped by Oldale (1969), and mapping was updated in 2006 by the Air Force Center for Environmental Excellence (AFCEE, 2006). This report updates the bedrock-surface map with new data points collected by using a passive seismic technique based on the horizontal-to-vertical spectral ratio (HVSR) of ambient seismic noise (Lane and others, 2008) and from borings drilled to bedrock since the 2006 map was prepared. The HVSR method is based on a relationship between the resonance frequency of ambient seismic noise as measured at land surface and the thickness of the unconsolidated sediments that overlie consolidated bedrock. The HVSR method was shown by Lane and others (2008) to be an effective method for determining sediment thickness on Cape Cod owing to the distinct difference in the acoustic impedance between the sediments and the underlying bedrock. The HVSR data for 164 sites were combined with data from 559 borings to bedrock in the study area to create a spatially distributed dataset that was manually contoured to prepare a topographic map of the bedrock surface. The interpreted bedrock surface generally slopes downward to the southeast as was shown on the earlier maps by Oldale (1969) and AFCEE (2006). The surface also has complex small-scale topography characteristic of a glacially eroded surface. More information about the methods used to prepare the map is given in the pamphlet that accompanies this plate.

  10. 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.

  11. Influence of bedrock lithology on strath terrace formation in the Willapa River watershed, SW Washington, USA

    Science.gov (United States)

    Schanz, S. A.; Montgomery, D. R.

    2013-12-01

    River terraces in tectonically active regions such as the Cascadia subduction margin have been utilized as late Quaternary markers of rock uplift and climate, yet the important role of bedrock lithology as a control on terrace formation is rarely considered. This study investigates lithologic controls on strath terrace formation in the Willapa River basin, situated halfway between the Olympic and Oregon Coast Ranges along the Cascadia subduction zone. The Willapa River and its tributaries alternate flow through easily erodible marine sedimentary and resistant basalt bedrock. We estimate rates of fluvial incision and infer patterns of rock uplift through a combination of field mapping, surveying terrace tread and strath elevations, and radiocarbon dating of terrace abandonment. A long-term steady state between incision and rock uplift is assumed for the basin, and incision rates are calculated as the strath elevation above present thalweg divided by the age of strath abandonment. Radiocarbon dates reveal two extensive terrace sets approximately 150 and 10,000 years old, resulting in a regional rock uplift rate of 0.4×0.1 mm/yr. Terraces are present only in sedimentary bedrock whereas basalt bedrock reaches run through deep, narrow valleys lacking extensive floodplains or terraces. The marine sedimentary units erode easily both laterally and vertically with active erosion of millimeter thick flakes on subaerially exposed bedrock. In contrast, basalt bedrock erodes preferentially in large blocks along fracture planes, resulting in less laterally erodible banks and higher vertical than lateral incision rates. We estimate rock uplift rates of less than 0.5 mm/yr are high enough to initiate strath terrace formation following large, long cycle impetuses such as climatic changes, provided the bedrock lithology is weak enough to allow lateral erosion as well as vertical incision. Thus, disturbances from large climatic or base level changes initiate terrace formation, but

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Dick, V.; Edwards, D. [Haley & Aldrich, Inc., New York, NY (United States)

    1997-12-31

    Funnel-and-gate technology provides a mechanism to passively treat groundwater contaminant plumes, but depends on placement of a sufficient barrier ({open_quotes}funnel{close_quotes}) in the plume flow path to channel the plume to a pass-through treatment zone ({open_quotes}gate{close_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}Y{close_quotes}shaped, 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.

  14. Geophysical characterization of fractured bedrock at Site 8, former Pease Air Force Base, Newington, New Hampshire

    Science.gov (United States)

    Mack, Thomas J.; Degnan, James R.

    2003-01-01

    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 beneath the former Pease Air Force Base, Newington, N.H. The following logs were used: caliper, fluid temperature and conductivity, natural gamma radiation, electromagnetic conductivity, optical and acoustic televiewer, and heat-pulse flowmeter. The logs indicate several foliation and fracture trends in the bedrock. Two fracture-correlated lineaments trending 28? and 29?, identified with low-altitude aerial photography, are coincident with the dominant structural trend. The eight boreholes logged at Site 8 generally have few fractures and have yields ranging from 0 to 40 gallons per minute. The fractures that probably resulted in high well yields (20?40 gallons per minute) strike northeast-southwest or by the right hand rule, have an orientation of 215?, 47?, and 51?. Two-dimensional direct-current resistivity methods were used to collect detailed subsurface information about the overburden, bedrock-fracture zone depths, and apparent-dip directions. Analysis of data inversions from data collected with dipole-dipole and Schlumberger arrays indicated electrically conductive zones in the bedrock that are probably caused by fractured rock. These zones are coincident with extensions of fracture-correlated lineaments. The fracture-correlated lineaments and geophysical-survey results indicate a possible northeast-southwest anisotropy to the fractured rock.

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

    Directory of Open Access Journals (Sweden)

    L. Purkamo

    2015-11-01

    Full Text Available 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.

  16. Modeled Top of the Older Bedrock Geomodel Unit (pmtop_f)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The pmtop_f grid represents the modeled elevation of the top of the Older Bedrock geomodel unit at a 500 foot resolution. It is one grid of a geomodel that consists...

  17. Movement of Landslide Triggered by Bedrock Exfiltration with Nonuniform Pore Pressure Distribution

    Science.gov (United States)

    Jan, C. D.; Jian, Z. K.

    2014-12-01

    Landslides are common phenomena of sediment movement in mountain areas and usually pose severe risks to people and infrastructure around those areas. The occurrence of landslides is influenced by groundwater dynamics and bedrock characteristics as well as by rainfall and soil-mass properties. The bedrock may drain or contribute to groundwater in the overlying soil mass, depending on the hydraulic conductivity, degree of fracturing, saturation, and hydraulic head. Our study here is based on the model proposed by Iverson (2005). The model describes the relation between landslide displacement and the shear-zone dilation/contraction of pore water pressure. To study landslide initiation and movement, a block soil mass sliding down an inclined beck-rock plane is governed by Newton's equation of motion, while both the bedrock exfiltration and excess pore pressure induced by dilatation or contraction of basal shear zone are described by diffusion equations. The Chebyshev collocation method was used to transform the governing equations to a system of first-order ordinary differential equations, without the need of iteration. Then a fourth-order Runge-Kutta scheme was used to solve these ordinary differential equations. The effects of nonuniform bedrock exfiltration pressure distributions, such as the delayed peak, central peak, and advanced peak distributions, on the time of landslide initiation and the speed of landslide movement were compared and discussed.

  18. Muon Tomography of Ice-filled Cleft Systems in Steep Bedrock Permafrost: A Proposal

    OpenAIRE

    Ihl, Matthias

    2010-01-01

    In this note, we propose a novel application of geoparticle physics, namely using a muon tomograph to study ice-filled cleft systems in steep bedrock permafrost. This research could significantly improve our understanding of high alpine permafrost in general and climate-permafrost induced rockfall in particular.

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

    International Nuclear Information System (INIS)

    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

  20. Integrated Characterization of DNAPL Source Zone Architecture in Clay Till and Limestone Bedrock

    DEFF Research Database (Denmark)

    Broholm, Mette Martina; Janniche, Gry Sander; Fjordbøge, Annika Sidelmann;

    2014-01-01

    activities of a distribution facility for perchloroethene (PCE) and trichloroethene (TCE) at the Naverland site near Copenhagen, Denmark, has resulted in PCE and TCE DNAPL impacts to a fractured clay till and an underlying fractured limestone aquifer/bedrock. The scope of the investigations was to evaluate...

  1. Bedrock displacements in Greenland manifest ice mass variations, climate cycles and climate change

    DEFF Research Database (Denmark)

    Bevis, Michael; Wahr, John; Khan, Shfaqat Abbas;

    2012-01-01

    The Greenland GPS Network (GNET) uses the Global Positioning System (GPS) to measure the displacement of bedrock exposed near the margins of the Greenland ice sheet. The entire network is uplifting in response to past and present-day changes in ice mass. Crustal displacement is largely accounted...

  2. Threshold bedrock channels in tectonically active mountains with frequent mass wasting

    Science.gov (United States)

    Korup, O.; Hayakawa, Y. S.; Codilean, A.; Oguchi, T.

    2013-12-01

    Models of how mountain belts grow and erode through time largely rely on the paradigm of fluvial bedrock incision as the main motor of response to differences in rock uplift, thus setting base levels of erosion in tectonically active landscapes. Dynamic feedbacks between rock uplift, bedrock river geometry, and mass wasting have been encapsulated within the concept of threshold hillslopes that attain a mechanically critical inclination capable of adjusting to fluvial incision rates via decreased stability and commensurately more frequent landsliding. Here we provide data that challenge the widely held view that channel steepness records tectonic forcing more faithfully than hillslope inclination despite much robust empirical evidence of such links between bedrock-river geometry and hillslope mass wasting. We show that the volume mobilized by mass wasting depends more on local topographic relief and the sinuosity of bedrock rivers than their mean normalized channel steepness. We derive this counterintuitive observation from an unprecedented inventory of ~300,000 landslides covering the tectonically active Japanese archipelago with substantial differences in seismicity, lithology, vertical surface deformation, topography, and precipitation variability. Both total landslide number and volumes increase nonlinearly with mean local relief even in areas where the fraction of steepest channel segments attains a constant threshold well below the maximum topographic relief. Our data document for the first time that mass wasting increases systematically with preferential steepening of flatter channel segments. Yet concomitant changes in mean channel steepness are negligible such that it remains a largely insensitive predictor of landslide denudation. Further, minute increases in bedrock-river sinuosity lead to substantial reduction in landslide abundance and volumes. Our results underline that sinuosity (together with mean local relief) is a key morphometric variable for

  3. REE potential of the Nordkinn Peninsula, North Norway: A comparison of soil and bedrock composition

    International Nuclear Information System (INIS)

    Highlights: • Soil geochemistry outlines an extensive REE anomaly on the Nordkinn Peninsula, North Norway. • Soil and bedrock geochemistry are compared with respect to REE and other HFSE. • Petrology of soil and rock samples reveals that the economic potential is limited. • Poor condition of REE minerals causes elevated REE concentrations in AR-digested soil samples. - Abstract: Regional-scale, low-density sampling, geochemical surveys using a variety of different sample materials have repeatedly indicated the Nordkinn Peninsula (northern Norway) as a substantial rare earth element (REE) anomaly. Recently, a more detailed soil geochemical survey, covering about 2000 km2 at a sample density of 1 site per 2 km2, was carried out in the area. The new geochemical survey outlined a large area (several hundred km2) where the soil samples contained several hundred and up to over 2000 mg/kg aqua regia extractable REE. In the surroundings of the highest soil anomalies, bedrock samples were collected for a mineralogical and compositional characterisation of the metasedimentary bedrock with focus on the possible economic potential. The REE concentrations obtained for aliquots of bedrock following aqua regia extraction, 4-Acid digestion and Li-borate fusion/decomposition closely match the results from soil pulps after an aqua regia extraction. Total contents for the REE determined in bedrock using the above methods range between 19 and 429 mg/kg, indicating an overall limited economic REE potential and the predominance of the light REE over the heavy REE. In terms of petrography, essentially all the bedrock samples are characterised by the presence of detrital, altered and locally even decomposed allanite (a LREE-incorporating, epidote-group mineral) and minor xenotime (a HREE-incorporating phosphate) while texturally stable REE phases are scarce. It is the poor condition of the REE minerals that makes them prone towards acidic leaching and, given similar results for

  4. New insights into the mechanics of fluvial bedrock erosion through flume experiments and theory

    Science.gov (United States)

    Lamb, Michael P.; Finnegan, Noah J.; Scheingross, Joel S.; Sklar, Leonard S.

    2015-09-01

    River incision into bedrock drives the topographic evolution of mountainous terrain and may link climate, tectonics, and topography over geologic time scales. Despite its importance, the mechanics of bedrock erosion are not well understood because channel form, river hydraulics, sediment transport, and erosion mechanics coevolve over relatively long time scales that prevent direct observations, and because erosive events occur intermittently and are difficult and dangerous to measure. Herein we synthesize how flume experiments using erodible bedrock simulants are filling these knowledge gaps by effectively accelerating the pace of landscape evolution under reduced scale in the laboratory. We also build on this work by providing new theory for rock resistance to abrasion, thresholds for plucking by vertical entrainment, sliding and toppling, and by assessing bedrock-analog materials. Bedrock erosion experiments in the last 15 years reveal that the efficiency of rock abrasion scales inversely with the square of rock tensile strength, sediment supply has a dominant control over bed roughness and abrasion rates, suspended sediment is an efficient agent of erosion, and feedbacks with channel form and roughness strongly influence erosion rates. Erodibility comparisons across rock, concrete, ice, and foam indicate that, for a given tensile strength, abrasion rates are insensitive to elasticity. The few experiments that have been conducted on erosion by plucking highlight the importance of block protrusion height above the river bed, and the dominance of block sliding and toppling at knickpoints. These observations are consistent with new theory for the threshold Shields stress to initiate plucking, which also suggests that erosion rates in sliding- and toppling-dominated rivers are likely transport limited. Major knowledge gaps remain in the processes of erosion via plucking of bedrock blocks where joints are not river-bed parallel; waterfall erosion by toppling and

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

    International Nuclear Information System (INIS)

    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

  6. Mineralogical sources of groundwater fluoride in Archaen bedrock/regolith aquifers: mass balances from the Peninsular Granite Complex, southern India

    Science.gov (United States)

    Hallett, Bethan; Burgess, William; Valsami-Jones, Eugenia

    2014-05-01

    Fluoride in groundwater-sourced drinking water is a widespread concern in India, particularly in the granitic gneiss bedrock/regolith catchments of Andhra Pradesh, one of the most severely affected states. Mobilisation of F- to groundwater is ultimately the consequence of bedrock weathering and regolith development, yet in crystalline bedrock/regolith terrain of the Peninsular Granite Complex, which constitutes a strategically important aquifer environment in India, uncertainties persist in relation to the relative contribution of the different F-bearing minerals and their distribution between the bedrock and the regolith. Even the relative significance of the bedrock and regolith as sources of fluoride to groundwater is disputed, as are explanations of seasonal and/or secular trends in groundwater F-. There are important implications for management of the groundwater resource. Understanding the mechanisms and progress of chemical weathering of the granitic gneiss is key to these questions, ie how effectively is F removed from its primary source(s) as the bedrock weathers? And, to what extent is F- flushed from the weathering profile and/or re-sequestered by secondary mineral phases as the regolith develops? To address these questions we have applied optical petrography, XRD, scanning electron microprobe analysis, whole-rock chemical analysis and leaching experiments to samples of bedrock and regolith from two catchments in Andhra Pradesh. We have quantified the distribution of F between its individual mineralogical sources, and between bedrock and regolith. Experiments show there is no straightforward relationship between whole-rock F content and leached [F-]; in some instances regolith samples leach higher F- concentrations than the fresh granitic gneiss. Results shed light on conflicting conceptual models of F release to groundwater in gneissic bedrock/regolith aquifers. Accounting for groundwater [F-], simple estimates of groundwater flux in the catchments

  7. Organic Carbon Stabilization of Soils Formed on Acidic and Calcareous Bedrocks in Neotropical Alpine Grassland, Peru

    Science.gov (United States)

    Yang, Songyu; Cammeraat, Erik; Jansen, Boris; Cerli, Chiara; Kalbitz, Karsten

    2016-04-01

    Increasing evidence shows that Neotropical alpine ecosystems are vulnerable to global change. Since soils in the alpine grasslands of the Peruvian Andean region have large soil organic carbon (SOC) stocks, profound understanding of soil organic matter (OM) stabilization mechanisms will improve the prediction of the feedback between SOC stocks and global change. It is well documented that poor-crystalline minerals and organo-metallic complexes significantly contribute to the OM stabilization in volcanic ash soils, including those in the Andean region. However, limited research has focused on non-ash soils that also express significant SOC accumulation. A pilot study of Peruvian Andean grassland soils suggests that lithology is a prominent factor for such carbon accumulation. As a consequence of contrasting mineral composition and pedogenic processes in soils formed on different non-volcanic parent materials, differences in OM stabilization mechanisms may be profound and consequently may respond differently to global change. Therefore, our study aims at a further understanding of carbon stocks and OM stabilization mechanisms in soils formed on contrasting bedrocks in the Peruvian Andes. The main objective is to identify and compare the roles that organo-mineral associations and aggregations play in OM stabilization, by a combination of selective extraction methods and fractionations based on density, particle size and aggregates size. Soil samples were collected from igneous acidic and calcareous sedimentary bedrocks in alpine grassland near Cajamarca, Peru (7.17°S, 78.63°W), at around 3700m altitude. Samples were taken from 3 plots per bedrock type by sampling distinguishable horizons until the C horizons were reached. Outcomes confirmed that both types of soil accumulate large amounts of carbon: 405.3±41.7 t/ha of calcareous bedrock soil and 226.0±5.6 t/ha of acidic bedrock soil respectively. In addition, extremely high carbon contents exceeding 90g carbon per

  8. 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. Significant predictors of arsenic in groundwater from bedrock aquifers for all three thresholds analyzed included geologic, geochemical, land use, hydrologic, topographic, and demographic factors. Among the three thresholds evaluated, there were some differences in explanatory variables, but many variables were the same. More than 250 individual predictor variables were assembled for this study and tested as potential predictor variables for the models. More than 1,700 individual measurements of arsenic concentration from a combination of public and private water-supply wells served as the dependent (or predicted) variable in the models. The statewide maps generated by the probability models are not designed to predict arsenic concentration in any single well, but they are expected to provide useful information in areas of the State that currently contain little to no data on arsenic concentration. They also may aid in resource decision making, in determining potential risk for private

  9. The Salzach Valley overdeeping: A most precise bedrock model of a major alpine glacial basin

    Science.gov (United States)

    Pomper, Johannes; Salcher, Bernhard; Eichkitz, Christoph

    2016-04-01

    Overdeepenings are impressive phenomena related to the erosion in the ablation zone of major glaciers. They are common features in glaciated and deglaciated regions worldwide and their sedimentary fillings may act as important archives for regional environmental change and glaciation history. Sedimentary fillings are also important targets of geotechnical exploration and construction including groundwater resource management, shallow geothermal exploitation, tunneling and the foundation of buildings. This is especially true in densely populated areas such as the European Alps and their foreland areas, regions which have been multiply glaciated during the last million years. However, due depths often exceeding some hundreds of meters, the overall knowledge on their geometry, formation and sedimentary content is still poor and commonly tied to some local spots. Here we present a bedrock model of the overall lower Salzach Valley, one of the largest glacial overdeepings in the European Alps. We utilized seismic sections from hydrocarbon exploration surveys and deep drillings together with topographic and modelling data to construct a 3D bedrock model. Through the existence of seismic inline and crossline valley sections, multiple drillings reaching the bedrock surface, log and abundant outcrop data we were, as far to our knowledge, able to create the most accurate digital bedrock topography of an alpine major overdeepening. We furthermore analyzed the sedimentary content of the valley as recorded by driller's lithologic logs. Our results suggest that the valley is far from being a regular U-shaped trough with constant depth, rather highlighting highs and lows of different magnitude and underground valley widths of variable extent. Data also indicates that the largest overdeepening of bedrock, reaching around 450 m below the alluvial fill, is not situated after a major glacial confluence following a prominent bedrock gorge but shifted several km down the valley. The

  10. 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

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

    International Nuclear Information System (INIS)

    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 10-7 m2/s. The corresponding mean of the hydraulic conductivity values for the intact rock measured using a 2 m packer interval is 8 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, 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 most evolved

  12. Mapping the geophysical bedrock of the Moesian Platform using H/V ratios and borehole data.

    Science.gov (United States)

    Florinela Manea, Elena; Michel, Clotaire; Fäh, Donat; Ortanza Cioflan, Carmen

    2016-04-01

    The strong effects at long periods observed in the extra-Carpathian area of Romania during large Vrancea intermediate-depth earthquakes were explained by the influence of both source mechanism and mechanical properties of the geological structure. Complex basin geometry and the low seismic velocities of the sediments are the primary responsible for the large amplification and long duration of the seismic records from the extra-Carpathian area during intermediate-depth earthquakes. The aim of this study is to map the geophysical bedrock of this area correlating and interpolating the results obtained from local resonance phenomena evaluation with the available surface geological data. The site was investigated through the computation of H/V spectral ratios from three-directional single station measurements of ambient vibration. The first step was to estimate the depth of the geophysical bedrock at all the Romanian seismic stations located in the extra-Carpathian area (velocity sensors) using the fundamental frequency retrieved from the H/V curves. In the second stage of the study all the relevant peaks from the H/V curves were interpreted in consonance with the available information of the geology. The geological data were obtained from the database developed in the national BIGSEES project by National Institute of Earth Physics. In this database are integrated all the geological, geophysical data from all the past projects, contracts, studies (as refraction, reflexion, etc.), geotechnical drillings and other information publicly available. The mapping of the geophysical bedrock was done interpolating the geological database and information gathered/resulted from H/V using a geographical informational system(GIS). The geology of this area displays very complex features as outcrops in small zones/lines/ near the Danube and then is gradually dipping to about 2 km depth in the N-NE. The depth of the bedrock is (nearly) constant around 100 m depth on the right side of

  13. Quantifying the role of forest soil and bedrock in the acid neutralization of surface water in steep hillslopes

    International Nuclear Information System (INIS)

    The role of soil and bedrock in acid neutralizing processes has been difficult to quantify because of hydrological and biogeochemical uncertainties. To quantify those roles, hydrochemical observations were conducted at two hydrologically well-defined, steep granitic hillslopes in the Tanakami Mountains of Japan. These paired hillslopes are similar except for their soils; Fudoji is leached of base cations (base saturation 30%), because the erosion rate is 100-1000 times greater. The results showed that (1) soil solution pH at the soil-bedrock interface at Fudoji (4.3) was significantly lower than that of Rachidani (5.5), (2) the hillslope discharge pH in both hillslopes was similar (6.7-6.8), and (3) at Fudoji, 60% of the base cations leaching from the hillslope were derived from bedrock, whereas only 20% were derived from bedrock in Rachidani. Further, previously published results showed that the stream pH could not be predicted from the acid deposition rate and soil base saturation status. These results demonstrate that bedrock plays an especially important role when the overlying soil has been leached of base cations. These results indicate that while the status of soil acidification is a first-order control on vulnerability to surface water acidification, in some cases such as at Fudoji, subsurface interaction with the bedrock determines the sensitivity of surface water to acidic deposition. - Bedrock plays a major role in neutralizing acid when overlying soils have been leached of base cations

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

    International Nuclear Information System (INIS)

    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)

  15. LNAPL recovery in permafrost fractured bedrock at the Colomac mine site, NWT

    International Nuclear Information System (INIS)

    This paper discussed a remediation project conducted to managed a diesel fuel spill at an abandoned mine site located in the Northwest Territories (NT). The site was underlain by fractured bedrock with between 0 to 5 m of overburden soil. More than 50,000 l of fuel were spilled at the fuel tank storage area of the mine between 1990 and 2003. Fuel seepage from the bedrock outcrops were observed adjacent to a nearby lake. A number of remediation techniques were used to control the spill. Measures included the blasting and excavation of the most heavily impacted area of the site as well as the use of a single well multi-phase extraction system. Use of the remedial techniques has resulted in the recovery of over 8000 litres of spilled fuel at the site.

  16. Baseline geochemistry of soil and bedrock Tshirege Member of the Bandelier Tuff at MDA-P

    Energy Technology Data Exchange (ETDEWEB)

    Warren, R.G.; McDonald, E.V.; Ryti, R.T.

    1997-08-01

    This report provides baseline geochemistry for soils (including fill), and for bedrock within three specific areas that are planned for use in the remediation of Material Disposal Area P (MDA-P) at Technical Area 16 (TA-16). The baseline chemistry includes leachable element concentrations for both soils and bedrock and total element concentrations for all soil samples and for two selected bedrock samples. MDA-P operated from the early 1950s to 1984 as a landfill for rubble and debris generated by the burning of high explosives (HE) at the TA-16 Burning Ground, HE-contaminated equipment and material, barium nitrate sand, building materials, and trash. The aim of this report is to establish causes for recognizable chemical differences between the background and baseline data sets. In many cases, the authors conclude that recognizable differences represent natural enrichments. In other cases, differences are best attributed to analytical problems. But most importantly, the comparison of background and baseline geochemistry demonstrates significant contamination for several elements not only at the two remedial sites near the TA-16 Burning Ground, but also within the entire region of the background study. This contamination is highly localized very near to the surface in soil and fill, and probably also in bedrock; consequently, upper tolerance limits (UTLs) calculated as upper 95% confidence limits of the 95th percentile are of little value and thus are not provided. This report instead provides basic statistical summaries and graphical comparisons for background and baseline samples to guide strategies for remediation of the three sites to be used in the restoration of MDA-P.

  17. Bellshill GOCADTM bedrock modelling (Clyde Project) : NS75NW, NS76NW and NS75SW

    OpenAIRE

    McCormac, M

    2011-01-01

    This report is the published product of a study by the British Geological Survey (BGS) that describes how the Bellshill (Clyde Catchment) GOCAD™ bedrock model was made. It is for BGS purposes and is a contribution to the Glasgow and Clyde Basin Cross-cutting Super-project. The report covers the data, constraints, geology, modelling process and outputs of the work. It should be used to understand the model in conjunction with the BGS model metadata and relevant sections of the G...

  18. Heterogeneous bedrock investigation for a closed-loop geothermal system: A case study

    OpenAIRE

    Radioti, Georgia; Delvoie, Simon; Charlier, Robert; Dumont, Gaël; Nguyen, Frédéric

    2016-01-01

    This paper investigates bedrock heterogeneity by applying three different geophysical approaches, in order to study the long-term behaviour and the interaction between closed-loop geothermal systems. The investigated site consists of four boreholes equipped with geothermal pipes on the campus of University of Liege, Belgium. The first approach includes acoustic borehole imaging, gamma-ray logging and cuttings observation and results to a detailed fracture characterisation, rock identification...

  19. The tensile capacity of steel pipe piles drilled into the bedrock

    OpenAIRE

    Sirén, Rosa

    2015-01-01

    This Master’s thesis focuses on drilled pipe piles and their ability to transfer tensile forces. The tensile forces affecting pile foundations are usually transferred to the bedrock by rock anchors. If drilled pipe piles could transfer some of these tension forces, foundation work would be faster, easier and more cost-effective. This thesis is a continuation of a study published in 2014, which also investigated the tensile capacity of drilled pipe piles. This thesis consists of two main ...

  20. The legacy of impact conditions in morphometrics of percussion marks on fluvial bedrock surfaces

    Science.gov (United States)

    Wilson, Andrew; Lavé, Jérôme

    2013-03-01

    Percussion, or impact, marks are a common type of bedrock bedform found on many fluvial bedrock channels and have been attributed to bedload impact. Little is known about the conditions under which they form and how these affect morphology and dimensions of impact mark craters. We present data from a set of experiments exploring the formation of percussion marks by bedload impact under controlled conditions (impact velocity, angle, and particle diameter) by quartz spheres onto polished marble plates through a water interface. Particle impact causes impact craters consisting of a central depressed pit and a surrounding raised crater rim under all impact conditions. Data from 699 impact experiments show that crater rims are always circular and crater diameter (ϕc, in m) scales with the kinetic energy of the particle normal to the surface immediately prior to impact (K.E., in J) by the relationship K.E. = 2.48 × 107ϕc3.188. We test this relationship on impact marks produced in a series of controlled flume experiments for a range of surface inclinations found in natural fluvial channel outcrops. Measurements of impact crater diameter were used to estimate K.E. using our empirical equation. Our model estimates very similar K.E. for impact craters produced in this quasinatural setting to those calculated from flume conditions when realistic values for mean impact velocity and mean impact angle are assumed. Applying this relationship to measurements of crater rim diameter in natural settings will allow the mapping of impact K.E. along and across channel reaches where these bedforms are found. Future numerical models of fluvial bedrock erosion based on impact K.E. could be field calibrated from measurements of percussion marks in marble channels or from installed marble slabs in other bedrock channel reaches.

  1. Active Microbial Communities Inhabit Sulphate-Methane Interphase in Deep Bedrock Fracture Fluids in Olkiluoto, Finland

    OpenAIRE

    Malin Bomberg; Mari Nyyssönen; Petteri Pitkänen; Anne Lehtinen; Merja Itävaara

    2015-01-01

    Active microbial communities of deep crystalline bedrock fracture water were investigated from seven different boreholes in Olkiluoto (Western Finland) using bacterial and archaeal 16S rRNA, dsrB, and mcrA gene transcript targeted 454 pyrosequencing. Over a depth range of 296–798 m below ground surface the microbial communities changed according to depth, salinity gradient, and sulphate and methane concentrations. The highest bacterial diversity was observed in the sulphate-methane mixing zon...

  2. Revealing the unexplored fungal communities in deep groundwater of crystalline bedrock fracture zones in Olkiluoto, Finland

    OpenAIRE

    Sohlberg, Elina; Bomberg, Malin; Miettinen, Hanna; Nyyssönen, Mari; Salavirta, Heikki; Vikman, Minna; Itävaara, Merja

    2015-01-01

    The diversity and functional role of fungi, one of the ecologically most important groups of eukaryotic microorganisms, remains largely unknown in deep biosphere environments. In this study we investigated fungal communities in packer-isolated bedrock fractures in Olkiluoto, Finland at depths ranging from 296 to 798 m below surface level. DNA- and cDNA-based high-throughput amplicon sequencing analysis of the fungal internal transcribed spacer (ITS) gene markers was used to examine the total ...

  3. Constraining Paleo-Glacier Dynamics Using Optically Stimulated Luminescence (OSL) Bedrock Exposure Dating

    Science.gov (United States)

    Brun, F.; Valla, P.; King, G. E.; Herman, F.

    2014-12-01

    Quantifying glacier dynamics over the late-Pleistocene remains an important challenge for understanding glacial response to climate change. Historical glacier reconstructions are spatially limited (e.g. the European Alps) and cover only the last ~100 yrs, restricting their use as paleoclimatic proxies. Bedrock dating methods such as Terrestrial Cosmogenic Nuclides (TCN) dating or lichenometry allows glacier fluctuations to be reconstructed over longer timescales. However, these methods have limited temporal resolution, and therefore do not enable accurate dating of recent glacier fluctuations (e.g. short glacier re-advances). Here, we use a novel in situ dating method based on Optically Stimulated Luminescence (OSL) to fill this temporal/spatial gap. OSL dating is based on the time-accumulation of trapped electrons in the lattice defects of minerals. OSL-exposure dating is based on the bleaching (i.e. resetting) of the minerals' luminescence signal when they are exposed to light (Sohbati et al., 2012 JGR-Solid Earth), which depends on exposure time, effective photon flux and light attenuation by minerals. We analyzed 10 samples in the Val d'Hérens (Swiss Alps) where post-LGM glacier dynamics remain poorly constrained and short glacier re-advances are thought to occur during the Holocene. Bedrock samples were drilled and small cores were sliced into 1-mm thick discs from which natural luminescence profiles were measured. We calibrated the luminescence model parameters using historically-exposed bedrock samples (~100 yr) near the Mont-Miné glacier, and used this on-site calibration to date surface exposure of glacial bedrock at various elevations along the valley; initial relative dating results are promising. Although OSL-exposure dating appears an efficient tool for historical glacier reconstructions, OSL bleaching over longer timescales (i.e. late-Pleistocene to Holocene) requires more investigation before use as a chronometer.

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

    OpenAIRE

    Raposo, J. R.; Molinero, J.; Dafonte, J.

    2012-01-01

    Quantification of groundwater recharge in crystalline rocks presents great difficulties due to high heterogeneity. Traditionally these rocks have been considered with very low permeability, and their groundwater resources have been usually neglected, although they can have local importance when the bedrock presents a net of fractures well developed. Current European Water Framework Directive requires an efficient management of all groundwater resources, which begins with a proper knowledge of...

  5. Baseline geochemistry of soil and bedrock Tshirege Member of the Bandelier Tuff at MDA-P

    International Nuclear Information System (INIS)

    This report provides baseline geochemistry for soils (including fill), and for bedrock within three specific areas that are planned for use in the remediation of Material Disposal Area P (MDA-P) at Technical Area 16 (TA-16). The baseline chemistry includes leachable element concentrations for both soils and bedrock and total element concentrations for all soil samples and for two selected bedrock samples. MDA-P operated from the early 1950s to 1984 as a landfill for rubble and debris generated by the burning of high explosives (HE) at the TA-16 Burning Ground, HE-contaminated equipment and material, barium nitrate sand, building materials, and trash. The aim of this report is to establish causes for recognizable chemical differences between the background and baseline data sets. In many cases, the authors conclude that recognizable differences represent natural enrichments. In other cases, differences are best attributed to analytical problems. But most importantly, the comparison of background and baseline geochemistry demonstrates significant contamination for several elements not only at the two remedial sites near the TA-16 Burning Ground, but also within the entire region of the background study. This contamination is highly localized very near to the surface in soil and fill, and probably also in bedrock; consequently, upper tolerance limits (UTLs) calculated as upper 95% confidence limits of the 95th percentile are of little value and thus are not provided. This report instead provides basic statistical summaries and graphical comparisons for background and baseline samples to guide strategies for remediation of the three sites to be used in the restoration of MDA-P

  6. Chemical weathering in active mountain belts controlled by stochastic bedrock landsliding

    Science.gov (United States)

    Emberson, Robert; Hovius, Niels; Galy, Albert; Marc, Odin

    2016-01-01

    A link between chemical weathering and physical erosion exists at the catchment scale over a wide range of erosion rates. However, in mountain environments, where erosion rates are highest, weathering may be kinetically limited and therefore decoupled from erosion. In active mountain belts, erosion is driven by bedrock landsliding at rates that depend strongly on the occurrence of extreme rainfall or seismicity. Although landslides affect only a small proportion of the landscape, bedrock landsliding can promote the collection and slow percolation of surface runoff in highly fragmented rock debris and create favourable conditions for weathering. Here we show from analysis of surface water chemistry in the Southern Alps of New Zealand that weathering in bedrock landslides controls the variability in solute load of these mountain rivers. We find that systematic patterns in surface water chemistry are strongly associated with landslide occurrence at scales from a single hillslope to an entire mountain belt, and that landslides boost weathering rates and river solute loads over decades. We conclude that landslides couple erosion and weathering in fast-eroding uplands and, thus, mountain weathering is a stochastic process that is sensitive to climatic and tectonic controls on mass wasting processes.

  7. Surface undulations of Antarctic ice streams tightly controlled by bedrock topography

    Directory of Open Access Journals (Sweden)

    J. De Rydt

    2012-10-01

    Full Text Available Full Stokes models predict that fast-flowing ice streams transmit information about their bedrock topography most efficiently to the surface for basal undulations with length scales between 1 and 20 times the mean ice thickness. This typical behaviour is independent on the precise values of the flow law and sliding law exponents, and should be universally observable. However, no experimental evidence for this important theoretical prediction has been obtained so far, hence ignoring an important test for the physical validity of current-day ice flow models. In our work we use recently acquired airborne radar data for the Rutford Ice Stream and Evans Ice Stream, and we show that the surface response of fast-flowing ice is highly sensitive to bedrock irregularities with wavelengths of several ice thicknesses. The sensitivity depends on the slip ratio, i.e. the ratio between mean basal sliding velocity and mean deformational velocity. We find that higher values of the slip ratio generally lead to a more efficient transfer, whereas the transfer is significantly dampened for ice that attains most of its surface velocity by creep. Our findings underline the importance of bedrock topography for ice stream dynamics on spatial scales up to 20 times the mean ice thickness. Our results also suggest that local variations in the flow regime and surface topography at this spatial scale cannot be explained by variations in basal slipperiness.

  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. PMID:23895551

  9. Stochastic Seismic Response of an Algiers Site with Random Depth to Bedrock

    International Nuclear Information System (INIS)

    Among the important effects of the Boumerdes earthquake (Algeria, May 21st 2003) was that, within the same zone, the destructions in certain parts were more important than in others. This phenomenon is due to site effects which alter the characteristics of seismic motions and cause concentration of damage during earthquakes. Local site effects such as thickness and mechanical properties of soil layers have important effects on the surface ground motions.This paper deals with the effect of the randomness aspect of the depth to bedrock (soil layers heights) which is assumed to be a random variable with lognormal distribution. This distribution is suitable for strictly non-negative random variables with large values of the coefficient of variation. In this case, Monte Carlo simulations are combined with the stiffness matrix method, used herein as a deterministic method, for evaluating the effect of the depth to bedrock uncertainty on the seismic response of a multilayered soil. This study considers a P and SV wave propagation pattern using input accelerations collected at Keddara station, located at 20 km from the epicenter, as it is located directly on the bedrock.A parametric study is conducted do derive the stochastic behavior of the peak ground acceleration and its response spectrum, the transfer function and the amplification factors. It is found that the soil height heterogeneity causes a widening of the frequency content and an increase in the fundamental frequency of the soil profile, indicating that the resonance phenomenon concerns a larger number of structures.

  10. Stochastic Seismic Response of an Algiers Site with Random Depth to Bedrock

    Science.gov (United States)

    Badaoui, M.; Berrah, M. K.; Mébarki, A.

    2010-05-01

    Among the important effects of the Boumerdes earthquake (Algeria, May 21st 2003) was that, within the same zone, the destructions in certain parts were more important than in others. This phenomenon is due to site effects which alter the characteristics of seismic motions and cause concentration of damage during earthquakes. Local site effects such as thickness and mechanical properties of soil layers have important effects on the surface ground motions. This paper deals with the effect of the randomness aspect of the depth to bedrock (soil layers heights) which is assumed to be a random variable with lognormal distribution. This distribution is suitable for strictly non-negative random variables with large values of the coefficient of variation. In this case, Monte Carlo simulations are combined with the stiffness matrix method, used herein as a deterministic method, for evaluating the effect of the depth to bedrock uncertainty on the seismic response of a multilayered soil. This study considers a P and SV wave propagation pattern using input accelerations collected at Keddara station, located at 20 km from the epicenter, as it is located directly on the bedrock. A parametric study is conducted do derive the stochastic behavior of the peak ground acceleration and its response spectrum, the transfer function and the amplification factors. It is found that the soil height heterogeneity causes a widening of the frequency content and an increase in the fundamental frequency of the soil profile, indicating that the resonance phenomenon concerns a larger number of structures.

  11. 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. PMID:27432726

  12. Geology, Bedrock, Bedrock Geology of the Cary 7.5-minute Quadrangle, Published in 2001, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Field Observation information as of 2001. It is described...

  13. Geology, Bedrock, Bedrock Geology of the Wake Forest 7.5-minute Quadrangle, Published in 2001, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2001. It is described as...

  14. Geology, Bedrock, Bedrock Geology of the Rolesville 7.5-minute Quadrangle, Published in 2001, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2001. It is described as...

  15. Geology, Bedrock, Bedrock geologic map compilation of the west half of the Asheville 1:100,000 scale map., Published in 2006, 1:100000 (1in=8333ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:100000 (1in=8333ft) scale, was produced all or in part from Field Survey/GPS information as of 2006. It is described...

  16. Modeling flow and sediment transport dynamics in the lowermost Mississippi River, Louisiana, USA, with an upstream alluvial-bedrock transition and a downstream bedrock-alluvial transition: Implications for land building using engineered diversions

    Science.gov (United States)

    Viparelli, Enrica; Nittrouer, Jeffrey A.; Parker, Gary

    2015-03-01

    The lowermost Mississippi River, defined herein as the river segment downstream of the Old River Control Structure and hydrodynamically influenced by the Gulf of Mexico, extends for approximately 500 km. This segment includes a bedrock (or more precisely, mixed bedrock-alluvial) reach that is bounded by an upstream alluvial-bedrock transition and a downstream bedrock-alluvial transition. Here we present a one-dimensional mathematical formulation for the long-term evolution of lowland rivers that is able to reproduce the morphodynamics of both the alluvial-bedrock and the bedrock-alluvial transitions. Model results show that the magnitude of the alluvial equilibrium bed slope relative to the bedrock surface slope and the depth of bedrock surface relative to the water surface base level strongly influence the mobile bed equilibrium of low-sloping river channels. Using data from the lowermost Mississippi River, the model is zeroed and validated at field scale by comparing the numerical results with field measurements. The model is then applied to predict the influence on the stability of channel bed elevation in response to delta restoration projects. In particular, the response of the river bed to the implementation of two examples of land-building diversions to extract water and sediment from the main channel is studied. In this regard, our model results show that engineered land-building diversions along the lowermost Mississippi River are capable of producing equilibrated bed profiles with only modest shoaling or erosion, and therefore, such diversions are a sustainable strategy for mitigating land loss within the Mississippi River Delta.

  17. River longitudinal profiles and bedrock incision models: Stream power and the influence of sediment supply

    Science.gov (United States)

    Sklar, Leonard; Dietrich, William E.

    The simplicity and apparent mechanistic basis of the stream power river incision law have led to its wide use in empirical and theoretical studies. Here we identify constraints on its calibration and application, and present a mechanistic theory for the effects of sediment supply on incision rates which spotlights additional limitations on the applicability of the stream power law. On channels steeper than about 20%, incision is probably dominated by episodic debris flows, and on sufficiently gentle slopes, sediment may bury the bedrock and prevent erosion. These two limits bound the application of the stream power law and strongly constrain the possible combination of parameters in the law. In order to avoid infinite slopes at the drainage divide in numerical models of river profiles using the stream power law it is commonly assumed that the first grid cell is unchanneled. We show, however, that the size of the grid may strongly influence the calculated equilibrium relief. Analysis of slope-drainage area relationships for a river network in a Northern California watershed using digital elevation data and review of data previously reported by Hack reveal that non-equilibrium profiles may produce well defined slope-area relationships (as expected in equilibrium channels), but large differences between tributaries may point to disequilibrium conditions. To explore the role of variations in sediment supply and transport capacity in bedrock incision we introduce a mechanistic model for abrasion of bedrock by saltating bedload. The model predicts that incision rates reach a maximum at intermediate levels of sediment supply and transport capacity. Incision rates decline away from the maximum with either decreasing supply (due to a shortage of tools) or increasing supply (due to gradual bed alluviation), and with either decreasing transport capacity (due to less energetic particle movement) or increasing transport capacity (due less frequent particle impacts per unit bed

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

    International Nuclear Information System (INIS)

    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 1.3-10-6 m2/s. The corresponding mean of the hydraulic conductivity values for the intact rock, measured using a 2 m packer interval is 4*10-11 m2/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 Kivetty is classified as fresh water and the

  19. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Bedrock Geology

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This tabular data set represents the area of bedrock geology types in square meters compiled for every catchment of MRB_E2RF1 catchments for Major River Basins...

  20. 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

  1. Bedrock temperature as a potential method for monitoring change in crustal stress: Theory, in situ measurement, and a case history

    Science.gov (United States)

    Chen, Shunyun; Liu, Peixun; Liu, Liqiang; Ma, Jin

    2016-06-01

    Experimental studies have confirmed that temperature is notably affected by rock deformation; therefore, change in crustal stress should be indicated by measurable changes in bedrock temperature. In this work, we investigated the possibility that the bedrock temperature might be used to explore the state of crustal stress. In situ measurement of bedrock temperature at three stations from 2011 to 2013 was used as the basis for the theoretical analysis of this approach. We began with theoretical analyses of temperature response to change in crustal stress, and of the effect of heat conduction. This allowed distinction between temperature changes produced by crustal stress (stress temperature) from temperature changes caused by conduction from the land surface (conduction temperature). Stress temperature has two properties (synchronous response and a high-frequency feature) that allow it to be distinguished from conduction temperature. The in situ measurements confirmed that apparently synchronous changes in the stress temperature of the bedrock occur and that there exist obvious short-term components of the in situ bedrock temperature, which agrees with theory. On 20 April 2013, an earthquake occurred 95 km away from the stations, fortuitously providing a case study by which to verify our method for obtaining the state of crustal stress using temperature. The results indicated that the level of local or regional seismic activity, representing the level of stress adjustment, largely accords with the stress temperature. This means that the bedrock temperature is a tool that might be applied to understand the state of stress during seismogenic tectonics. Therefore, it is possible to record changes in the state of crustal stress in a typical tectonic position by long-term observation of bedrock temperature. Hereby, the measurement of bedrock temperature has become a new tool for gaining insight into changes in the status of shallow crustal stress.

  2. Transient response of bedrock channel networks to Pleistocene sea-level forcing in the Oregon Coast Range

    OpenAIRE

    Santaniello, David J.

    2015-01-01

    Although sea level has fluctuated repeatedly over the Pleistocene by up to 120 meters, how (or whether) this cyclic base level forcing impacts the development of bedrock river profiles in tectonically active settings is poorly understood. A major reason for this uncertainty is that bedrock river channels in unglaciated locations are typically buried at their mouths under sediment resulting from the Holocene marine transgression, making direct observations impossible. Here I present a novel ...

  3. Spatial correlation between radon (222Rn) in groundwater and bedrock uranium (238U): GIS and geostatistical analyses

    International Nuclear Information System (INIS)

    This study describes approaches to create surface maps of radon in groundwater based on measurements of radon (222Rn) in drilled bedrock wells at unevenly distributed sites and uranium bedrock maps from the South East of Sweden, the Ostergotland county (N 58o14' - N 58o56' and E 14o 53' - E 16o 06'), see figure 1. Geostatistical techniques of inverse distance weighted (IDW), kriging and cokriging were compared in terms of their interpolation power and correlation between the produced radon in the water layer and the bedrock uranium layer. The goal of these analyses and calculation is to improve our understanding concerning the factors influencing the transport of radon. Therefor, these interpolation techniques were investigated by optimizing parameters that are used in the specific interpolation. Using the IDW interpolator method at fixed radius enabled us to determine the linkage or search distances for auto correlation, and linkage between radon in water and bedrock. This method showed good agreement with the cokriging method with using uranium concentration as a secondary variable. Good interpolation layer (with least root mean square errors RMSE 232) were obtained by kriging. However, the kriging radon surface showed poor correlation with bedrock uranium layers. The best radon in water layer that match with uranium in bedrock layer was produced using IDW interpolator (RMSE 377, using all points). The correlation coefficient (R2) is 0.5 while for the kriging method the best correlation is R2 0.1. A compromise between the two approaches is demonstrated. (Author)

  4. Altitude, depth, and thickness of the Galena-Platteville Bedrock Unit in the subcrop area of Illinois and Wisconsin

    Science.gov (United States)

    Brown, Timothy A.; Dunning, Charles P.; Sharpe, Jennifer B.

    2000-01-01

    The Galena-Platteville bedrock unit is a carbonate deposit of Ordovician age, composed of the Galena and Platteville Groups in Illinois and the Sinnippee Group in Wisconsin. It is the uppermost bedrock unit (subcrop) in most of northern Illinois and southern and eastern Wisconsin. The subcrop area is shaded in figure 1 of sheet 1 (Batten and others, 1997). The unit is predominately dolomite, with limestone in some areas, and has a weathered surface. Across the subcrop area, the hydrologic characteristics of the bedrock unit vary substantially. The bedrock unit may be either a confining unit or an aquifer. In areas where the Galena-Platteville bedrock unit is an aquifer, the unit is a dependable source of water for many private wells and some municipal-water-supply systems. Ground water in the Galena-Platteville bedrock aquifer is susceptible to contamination because the bedrock unit is near land surface in much of the study area, and the fractures in the unit allow rapid movement of water providing limited capacity to attenuate contaminants. The subcrop (study) area covers approximately 7,850 square miles in northern Illinois and Wisconsin. In the study area, volatile organic compounds and other contaminants have been detected in the aquifer at various sites (Mills, 1993; Kay and others, 1994). Many sources of contaminants, including landfills and industrial facilities, are known or suspected. In order to determine the possible effects of contamination on the ground-water supply, an understanding of the regional hydrogeologic framework of the Galena-Platteville bedrock unit is needed. Published and unpublished map and point data describing the geologic properties of the Galena-Platteville bedrock unit are available from many sources. The U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA), has selected and compiled a large portion of the available data to create computer data bases and maps. The objective of this

  5. Revealing the unexplored fungal communities in deep groundwater of crystalline bedrock fracture zones in Olkiluoto, Finland

    Directory of Open Access Journals (Sweden)

    Elina eSohlberg

    2015-06-01

    Full Text Available The diversity and functional role of fungi, one of the ecologically most important groups of eukaryotic microorganisms, remains largely unknown in deep biosphere environments. In this study we investigated fungal communities in packer-isolated bedrock fractures in Olkiluoto, Finland at depths ranging from 296 m to 798 m below surface level. DNA- and cDNA-based high-throughput amplicon sequencing analysis of the fungal internal transcribed spacer (ITS gene markers was used to examine the total fungal diversity and to identify the active members in deep fracture zones at different depths. Results showed that fungi were present in fracture zones at all depths and fungal diversity was higher than expected. Most of the observed fungal sequences belonged to the phylum Ascomycota. Phyla Basidiomycota and Chytridiomycota were only represented as a minor part of the fungal community. Dominating fungal classes in the deep bedrock aquifers were Sordariomycetes, Eurotiomycetes and Dothideomycetes from the Ascomycota phylum and classes Microbotryomycetes and Tremellomycetes from the Basidiomycota phylum, which are the most frequently detected fungal taxa reported also from deep sea environments. In addition some fungal sequences represented potentially novel fungal species. Active fungi were detected in most of the fracture zones, which proves that fungi are able to maintain cellular activity in these oligotrophic conditions. Possible roles of fungi and their origin in deep bedrock groundwater can only be speculated in the light of current knowledge but some species may be specifically adapted to deep subsurface environment and may play important roles in the utilization and recycling of nutrients and thus sustaining the deep subsurface microbial community.

  6. Is Frost Cracking By Segregation Ice Growth One of the Mechanisms That Erode Bedrock River Margins?

    Science.gov (United States)

    Alden, L. L.; Sklar, L. S.

    2014-12-01

    Rivers cut vertically and laterally into bedrock. However, control on the width of bedrock rivers is an unsolved problem. In alpine settings, frost cracking is one of the mechanisms that break down bedrock. Segregation ice drives growth of ice lenses within rock masses. When the temperature of the rock is within the "frost cracking window" of -3 to -8 °C, ice lenses can attract liquid water. Expanding ice lenses can exert sufficient pressure to fracture the rock. We hypothesize that alpine rivers may promote segregation ice growth at the river margin by supplying water, but also may inhibit frost cracking by supplying heat. We find support for this hypothesis in data collected along the Tuolumne and Mokelumne rivers in the Sierra Nevada, California. A 1D heat flow model predicts that frost cracking should occur above 2325 masl in this area. To test for a river effect, we measured fracture density along the Tuolumne River at ~2600 masl, finding that density at the river margin is significantly greater than on adjacent hillslopes in the Cathedral Peak granodiorite. We then deployed data loggers on the Mokelumne River (at 2486 masl) over the winter of 2013/2014 to record water, surface and subsurface rock temperatures at varying depths and distances from the river. Temperatures within the frost cracking window were only recorded at a distance of ~5 m from the river, suggesting an insulating effect from the river and snow cover. Rock temperatures 1 m deep equilibrated at ~ 2 °C, significantly colder than predicted by the 1D model. Ongoing work includes terrestrial LIDAR scans to detect erosion of the river bank at the Mokelumne site, and development of a 2D heat flow model to predict subsurface rock temperatures for varying surface boundary conditions and channel morphology. We expect that further analysis will reveal systematic relationships between the surface boundary conditions and rock temperature at depth, enabling predictive modeling of frost cracking

  7. 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.

  8. Bedrock gorges in the central mainland Kachchh: Implications for landscape evolution

    Indian Academy of Sciences (India)

    M G Thakkar; B Goyal; A K Patidar; D M Maurya; L S Chamyal

    2006-04-01

    Kachchh possesses a fault-controlled first-order topography and several geomorphic features indicative of active tectonics.Though coseismic neotectonic activity is believed to be the major factor in the evolution of the landscape,detailed documentation and analysis of vital landscape features like drainage characteristics,bedrock gorges and terraces are lacking.The present study is a site-speci fic documentation of gorges developed in the central part of the mainland Kachchh.We analyzed and interpreted four gorges occurring on either side of Katrol Hill Fault (KHF).The Khari river gorge is endowed with six levels of bedrock terraces,some of which are studded with large potholes and flutings.Since no active development of potholes is observed along the rivers in the present day hyper-arid conditions,we infer an obvious linkage of gorges to the humid phases,which provided high energy runoff for the formation of gorges and distinct bedrock terraces and associated erosional features.Development of gorges within the miliolites and incision in the fluvial deposits to the south of the KHF indicates that the gorges were formed during Early Holocene.However,ubi-quitous occurrence of gorges along the streams to the south of KHF,the uniformly N40°E trend of the gorges,their close association with transverse faults and the short length of the exceptionally well developed Khari river gorge in the low-relief rocky plain to the north of KHF suggests an important role of neotectonic movements.

  9. Revealing the unexplored fungal communities in deep groundwater of crystalline bedrock fracture zones in Olkiluoto, Finland.

    Science.gov (United States)

    Sohlberg, Elina; Bomberg, Malin; Miettinen, Hanna; Nyyssönen, Mari; Salavirta, Heikki; Vikman, Minna; Itävaara, Merja

    2015-01-01

    The diversity and functional role of fungi, one of the ecologically most important groups of eukaryotic microorganisms, remains largely unknown in deep biosphere environments. In this study we investigated fungal communities in packer-isolated bedrock fractures in Olkiluoto, Finland at depths ranging from 296 to 798 m below surface level. DNA- and cDNA-based high-throughput amplicon sequencing analysis of the fungal internal transcribed spacer (ITS) gene markers was used to examine the total fungal diversity and to identify the active members in deep fracture zones at different depths. Results showed that fungi were present in fracture zones at all depths and fungal diversity was higher than expected. Most of the observed fungal sequences belonged to the phylum Ascomycota. Phyla Basidiomycota and Chytridiomycota were only represented as a minor part of the fungal community. Dominating fungal classes in the deep bedrock aquifers were Sordariomycetes, Eurotiomycetes, and Dothideomycetes from the Ascomycota phylum and classes Microbotryomycetes and Tremellomycetes from the Basidiomycota phylum, which are the most frequently detected fungal taxa reported also from deep sea environments. In addition some fungal sequences represented potentially novel fungal species. Active fungi were detected in most of the fracture zones, which proves that fungi are able to maintain cellular activity in these oligotrophic conditions. Possible roles of fungi and their origin in deep bedrock groundwater can only be speculated in the light of current knowledge but some species may be specifically adapted to deep subsurface environment and may play important roles in the utilization and recycling of nutrients and thus sustaining the deep subsurface microbial community. PMID:26106376

  10. Host Rock Classification (HRC) system for nuclear waste disposal in crystalline bedrock

    OpenAIRE

    Hagros, Annika

    2006-01-01

    A new rock mass classification scheme, the Host Rock Classification system (HRC-system) has been developed for evaluating the suitability of volumes of rock mass for the disposal of high-level nuclear waste in Precambrian crystalline bedrock. To support the development of the system, the requirements of host rock to be used for disposal have been studied in detail and the significance of the various rock mass properties have been examined. The HRC-system considers both the long-term safety of...

  11. Applicability of reflection seismic measurements in detailed characterization of crystalline bedrock

    International Nuclear Information System (INIS)

    Posiva carried out a seismic survey in the access tunnel of the underground research facility ONKALO in 2009. The survey contributes the detailed characterization of the bedrock in the final disposal of spent nuclear fuel. The aim of this work was to examine the geophysical and geological properties of the chosen tunnel intersections to clarify the important characteristics for reflection generation, and evaluate applicability of this survey for characterization of crystalline bedrock. The seismic result consists of 24 projected amplitude images in 12 different angles. The size of an image is 260*300 m. The amount of digitized reflectors is over 100 and all of them could not be included in this work. The study was limited to 14 intersections that were considered important: brittle fault intersections, tunnel-crosscutting fractures, or lithological contacts. Presence of a brittle fault zone or a tunnel-crosscutting fracture limits the suitable bedrock volume for depositing the nuclear fuel canisters, and wide lithological contacts are a common source of reflection. The seismic data was compared to the existing geological, hydrogeological and geophysical data got from the pilot holes and the tunnel. The most important characteristics were fractures: orientation, fillings, and thickness of the fillings, alteration and water leakage. Geophysically interesting was density, seismic velocities and their products: acoustic impedance and synthetic seismograms. Calculated acoustic impedances showed some differences between cases, but they did not indicate the presence of a reflector. The most common cause of reflector was undulating slickensided, highly altered, tunnel-crosscutting fracture that had thick fracture-fillings and water present. Water was included five times in interpreted reflectors. Also few reflectors were connected to varying mineralogy. Few problematic cases occurred, where a geological feature and a reflection did not correlate, and three of the cases with

  12. 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.

  13. New bedrock map of Dome C, Antarctica, and morphostructural interpretation of the area

    OpenAIRE

    Forieri, A.; Università degli Studi di Milano, Sez. Geofisica, Via Cicognara 7, 20129 Milano - Italia; Zuccoli, L.; Università degli Studi di Milano, Sez. Geologia, Via Mangiagalli 34, I-20133 Milan, Italy; Bini, A.; Università degli Studi di Milano, Sez. Geologia, Via Mangiagalli 34, I-20133 Milan, Italy; Zirizzotti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Remy, F.; Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, 18 av. Edouard Belin, 31055 Toulouse Cedex, France; Tabacco, I. E.; Università degli Studi di Milano, Sez. Geofisica, Via Cicognara 7, I-20129 Milan, Italy

    2004-01-01

    A new bedrock map of the Dome C area is presented, based on all radar data collected during Italian Antarctic Expeditions in 1995, 1997, 1999 and 2001. The map clearly distinguishes the Dome C plateau, along with valleys and ridges. The plateau develops at three different altimetric levels, and its morphology is characterized by hills and closed depressions. There are no visible features which can be ascribed to glacial erosion or deposition. The major valley is 15km wide and 500m deep; it...

  14. 3D-model of salinity of bedrock groundwater at Olkiluoto

    International Nuclear Information System (INIS)

    Posiva carries out investigations and preparations for spent nuclear fuel disposal into Finnish bedrock at Olkiluoto. The salinity of groundwater in the bedrock, its distribution and quantity are important factors in planning the facilities for final disposal of the spent nuclear fuel, and in assessing the functionality and safety of the facilities. Belonging to site investigations, JP-Fintact carried out compilation of 3-D volume model of total dissolved salinity (TDS, g/l) distribution of Olkiluoto site. The model covers the central part of Olkiluoto island bedrock volume. The model update replaces the previous works. Current model is more simplified presentation of observations than previously, containing essentially enhanced amount and coverage of TDS data. The model is based on the hydrochemical TDS observations and the hydrology groundwater electrical conductivity data of flow logging converted to TDS. Observations confirm the concept of layered, diffuse behavior of increasing salinity according to depth. Model has been presented with four salinity classes (30 g/l), and two boundary surfaces have been shown between the volumes occupied by these classes. The boundaries are subhorizontal. The local distribution is heterogeneous, and its description will benefit of new data when available. The indirect geophysical electrical borehole logging and electromagnetic frequency sounding observation data offers dense data coverage, also outside of other borehole observations and the volume covered by boreholes. The usage was based on the ratio of groundwater electrical conductivity and TDS, and on the dependencies between bedrock electrical conductivity, porosity and groundwater electrical conductivity. The geophysical data values have variability compared to the model. The gathered TDS observations have been compiled into TDS boundaries and layers into Posiva's ROCK-CAD system. Graphical presentations of the model have been compiled. The model has then been referred to

  15. 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

  16. 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)

    The assimilation of CO2 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; CO32-: 104, 98 and 190 μM; CH4: 26, 27 and 31 μl/l and N2: 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; CO32-: 50, 57 and 158 μM; CH4: 245, 170 and 290 μl/l and N2: 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 105 unattached bacteria ml-1 groundwater and 0.94 to 1.2 x 105 attached bacteria cm-2 on the surface in Laxemar and from 1.6 x 103 up to 3.2 x 105 bacteria ml-1 groundwater and from 2.4 x 105 up to 1.1 x 107 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 103 up to 106 more attached than unattached bacteria in a water conducting channel in crystalline bedrock. (54 refs., 23 figs., 10 tabs.) (au)

  17. TORSIONAL VIBRATIONS OF A RIGID CIRCULAR PLATE ON SATURATED STRATUM OVERLAYING BEDROCK

    Institute of Scientific and Technical Information of China (English)

    CaiYuanqiang; WuDazhi; XuChangjie

    2005-01-01

    The torsional vibration of a rigid plate resting on saturated stratum overlaying bedrock has been analysed for the first time. The dynamic governing differential equations for saturated poroelastic medium are solved by employing the technology of Hankel transform. By taking into account the boundary conditions, the dual integral equations of torsional vibration of a rigid circular plate are established, which are further converted into a Fredholm integral equation of the second kind. Subsequently, the dynamic compliance coefficients of the foundation on saturated stratum, the contact shear stress under the foundation and the angular amplitude of the foundation are evaluated. Numerical results indicate that, when the dimensionless height is bigger than 5, saturated stratum overlaying bedrock can be treated as saturated half space approximately. When the dimensionless frequency is low, the permeability of the soil must be taken into account. Furthermore, when the vibration frequency is a constant, the height of the saturated stratum has a slight effect on the dimensionless contact shear stress under the foundation.

  18. Measurements of hydraulic conductivity in deep bedrock at Palmottu, Outokumpu, Pori and Ylivieska

    International Nuclear Information System (INIS)

    Hydraulic conductivity of the bedrock was studied using a double packer equipment fitting the small-diameter drillholes (46 mm). Test method was a slug test, in which the pressure of the test section is reduced by removing water from a tube connected to the test section and, subsequently, monitoring the recovery of the original pressure. In the work, methods of interpretation suitable for the test method are examined, and compared by means of graphical simulations. Their relevance in the case of measurements in fractured crystalline bedrock are discussed. In the method of Hvorslev, the recovery rate is assumed to be directly proportional to residual drawdown and to the hydraulic conductivity of the test section and, consequently, the effect of specific storage is neglected. In other methods of interpretations (e.g. 'Cooper'- method), assuming radial flow from porous aquifer, specific storage is taken into consideration. Different methods of interpretation lead to dissimilar theoretical responses on recovery vs. time graphics. Skin-effect and outer boundary effects also have an influence on the shape of recovery curve. There is no major differences in K-values obtained by different methods of interpretation. The study sites represent different lithological environments, comprising migmatitic gneisses with granitic interlayers (Palmottu); a complex association of serpentine, black schist, quartzite, dolomite and scram (Outokumpu); arkosic sandstone (Pori); and mafic/ultramafic intrusion (Ylivieska)

  19. Active Microbial Communities Inhabit Sulphate-Methane Interphase in Deep Bedrock Fracture Fluids in Olkiluoto, Finland

    Science.gov (United States)

    Bomberg, Malin; Nyyssönen, Mari; Pitkänen, Petteri; Lehtinen, Anne; Itävaara, Merja

    2015-01-01

    Active microbial communities of deep crystalline bedrock fracture water were investigated from seven different boreholes in Olkiluoto (Western Finland) using bacterial and archaeal 16S rRNA, dsrB, and mcrA gene transcript targeted 454 pyrosequencing. Over a depth range of 296–798 m below ground surface the microbial communities changed according to depth, salinity gradient, and sulphate and methane concentrations. The highest bacterial diversity was observed in the sulphate-methane mixing zone (SMMZ) at 250–350 m depth, whereas archaeal diversity was highest in the lowest boundaries of the SMMZ. Sulphide-oxidizing ε-proteobacteria (Sulfurimonas sp.) dominated in the SMMZ and γ-proteobacteria (Pseudomonas spp.) below the SMMZ. The active archaeal communities consisted mostly of ANME-2D and Thermoplasmatales groups, although Methermicoccaceae, Methanobacteriaceae, and Thermoplasmatales (SAGMEG, TMG) were more common at 415–559 m depth. Typical indicator microorganisms for sulphate-methane transition zones in marine sediments, such as ANME-1 archaea, α-, β- and δ-proteobacteria, JS1, Actinomycetes, Planctomycetes, Chloroflexi, and MBGB Crenarchaeota were detected at specific depths. DsrB genes were most numerous and most actively transcribed in the SMMZ while the mcrA gene concentration was highest in the deep methane rich groundwater. Our results demonstrate that active and highly diverse but sparse and stratified microbial communities inhabit the Fennoscandian deep bedrock ecosystems. PMID:26425566

  20. Active Microbial Communities Inhabit Sulphate-Methane Interphase in Deep Bedrock Fracture Fluids in Olkiluoto, Finland

    Directory of Open Access Journals (Sweden)

    Malin Bomberg

    2015-01-01

    Full Text Available Active microbial communities of deep crystalline bedrock fracture water were investigated from seven different boreholes in Olkiluoto (Western Finland using bacterial and archaeal 16S rRNA, dsrB, and mcrA gene transcript targeted 454 pyrosequencing. Over a depth range of 296–798 m below ground surface the microbial communities changed according to depth, salinity gradient, and sulphate and methane concentrations. The highest bacterial diversity was observed in the sulphate-methane mixing zone (SMMZ at 250–350 m depth, whereas archaeal diversity was highest in the lowest boundaries of the SMMZ. Sulphide-oxidizing ε-proteobacteria (Sulfurimonas sp. dominated in the SMMZ and γ-proteobacteria (Pseudomonas spp. below the SMMZ. The active archaeal communities consisted mostly of ANME-2D and Thermoplasmatales groups, although Methermicoccaceae, Methanobacteriaceae, and Thermoplasmatales (SAGMEG, TMG were more common at 415–559 m depth. Typical indicator microorganisms for sulphate-methane transition zones in marine sediments, such as ANME-1 archaea, α-, β- and δ-proteobacteria, JS1, Actinomycetes, Planctomycetes, Chloroflexi, and MBGB Crenarchaeota were detected at specific depths. DsrB genes were most numerous and most actively transcribed in the SMMZ while the mcrA gene concentration was highest in the deep methane rich groundwater. Our results demonstrate that active and highly diverse but sparse and stratified microbial communities inhabit the Fennoscandian deep bedrock ecosystems.

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

    International Nuclear Information System (INIS)

    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 m3/(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.)

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

    International Nuclear Information System (INIS)

    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

  3. Sediment transport through self-adjusting, bedrock-walled waterfall plunge pools

    Science.gov (United States)

    Scheingross, Joel S.; Lamb, Michael P.

    2016-05-01

    Many waterfalls have deep plunge pools that are often partially or fully filled with sediment. Sediment fill may control plunge-pool bedrock erosion rates, partially determine habitat availability for aquatic organisms, and affect sediment routing and debris flow initiation. Currently, there exists no mechanistic model to describe sediment transport through waterfall plunge pools. Here we develop an analytical model to predict steady-state plunge-pool depth and sediment-transport capacity by combining existing jet theory with sediment transport mechanics. Our model predicts plunge-pool sediment-transport capacity increases with increasing river discharge, flow velocity, and waterfall drop height and decreases with increasing plunge-pool depth, radius, and grain size. We tested the model using flume experiments under varying waterfall and plunge-pool geometries, flow hydraulics, and sediment size. The model and experiments show that through morphodynamic feedbacks, plunge pools aggrade to reach shallower equilibrium pool depths in response to increases in imposed sediment supply. Our theory for steady-state pool depth matches the experiments with an R2 value of 0.8, with discrepancies likely due to model simplifications of the hydraulics and sediment transport. Analysis of 75 waterfalls suggests that the water depths in natural plunge pools are strongly influenced by upstream sediment supply, and our model provides a mass-conserving framework to predict sediment and water storage in waterfall plunge pools for sediment routing, habitat assessment, and bedrock erosion modeling.

  4. Heterotrophic communities supplied by ancient organic carbon predominate in deep fennoscandian bedrock fluids.

    Science.gov (United States)

    Purkamo, Lotta; Bomberg, Malin; Nyyssönen, Mari; Kukkonen, Ilmo; Ahonen, Lasse; Itävaara, Merja

    2015-02-01

    The deep subsurface hosts diverse life, but the mechanisms that sustain this diversity remain elusive. Here, we studied microbial communities involved in carbon cycling in deep, dark biosphere and identified anaerobic microbial energy production mechanisms from groundwater of Fennoscandian crystalline bedrock sampled from a deep drill hole in Outokumpu, Finland, by using molecular biological analyses. Carbon cycling pathways, such as carbon assimilation, methane production and methane consumption, were studied with cbbM, rbcL, acsB, accC, mcrA and pmoA marker genes, respectively. Energy sources, i.e. the terminal electron accepting processes of sulphate-reducing and nitrate-reducing communities, were assessed with detection of marker genes dsrB and narG, respectively. While organic carbon is scarce in deep subsurface, the main carbon source for microbes has been hypothesized to be inorganic carbon dioxide. However, our results demonstrate that carbon assimilation is performed throughout the Outokumpu deep scientific drill hole water column by mainly heterotrophic microorganisms such as Clostridia. The source of carbon for the heterotrophic microbial metabolism is likely the Outokumpu bedrock, mainly composed of serpentinites and metasediments with black schist interlayers. In addition to organotrophic metabolism, nitrate and sulphate are other possible energy sources. Methanogenic and methanotrophic microorganisms are scarce, but our analyses suggest that the Outokumpu deep biosphere provides niches for these organisms; however, they are not very abundant. PMID:25260922

  5. Active Microbial Communities Inhabit Sulphate-Methane Interphase in Deep Bedrock Fracture Fluids in Olkiluoto, Finland.

    Science.gov (United States)

    Bomberg, Malin; Nyyssönen, Mari; Pitkänen, Petteri; Lehtinen, Anne; Itävaara, Merja

    2015-01-01

    Active microbial communities of deep crystalline bedrock fracture water were investigated from seven different boreholes in Olkiluoto (Western Finland) using bacterial and archaeal 16S rRNA, dsrB, and mcrA gene transcript targeted 454 pyrosequencing. Over a depth range of 296-798 m below ground surface the microbial communities changed according to depth, salinity gradient, and sulphate and methane concentrations. The highest bacterial diversity was observed in the sulphate-methane mixing zone (SMMZ) at 250-350 m depth, whereas archaeal diversity was highest in the lowest boundaries of the SMMZ. Sulphide-oxidizing ε-proteobacteria (Sulfurimonas sp.) dominated in the SMMZ and γ-proteobacteria (Pseudomonas spp.) below the SMMZ. The active archaeal communities consisted mostly of ANME-2D and Thermoplasmatales groups, although Methermicoccaceae, Methanobacteriaceae, and Thermoplasmatales (SAGMEG, TMG) were more common at 415-559 m depth. Typical indicator microorganisms for sulphate-methane transition zones in marine sediments, such as ANME-1 archaea, α-, β- and δ-proteobacteria, JS1, Actinomycetes, Planctomycetes, Chloroflexi, and MBGB Crenarchaeota were detected at specific depths. DsrB genes were most numerous and most actively transcribed in the SMMZ while the mcrA gene concentration was highest in the deep methane rich groundwater. Our results demonstrate that active and highly diverse but sparse and stratified microbial communities inhabit the Fennoscandian deep bedrock ecosystems. PMID:26425566

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

    International Nuclear Information System (INIS)

    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

  7. 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.

  8. Modeling of airborne electromagnetic anomalies related to fractured bedrock and overburden

    International Nuclear Information System (INIS)

    Responses of a multifrequency, multicoil airborne electromagnetic (AEM) system were modeled using numerical techniques. Special emphasis was given to poor, three-dimensional electrical conductors embedded both in the bedrock and in the overburden. The results cover vertical coaxial and horizontal coplanar configurations and three frequencies: 888 Hz, 7837 Hz and 51250 Hz. The models studied are signal conductors in free space, and single or multiple conductors embedded in a host rock of high but finite resistivity (5000 Wm) and overlain by a layer of overburden with finite resistivity and thickness. Two different types of computer software were used in the modelling: the free-space PLATE code, and the EM3D set of codes. Modeling results are given both as profiles and as charasteristic diagrams for the various coil configuration - conductor-model combinations. On the basis of the modeling results, limits of detectability for poor conductors have been determined. The study is a part of the preliminary site investigations for the radioactive waste disposal in Finnish bedrock

  9. Environmental isotope studies on groundwater from the crystalline bedrock in Finland

    International Nuclear Information System (INIS)

    Full text: Environmental isotope research on groundwater from crystalline bedrock in Finland is focused on: - investigations of coastal brackish and saline groundwater, - site investigations for nuclear waste disposal, and - a regional study of deep saline groundwater. Geochemical evolution of bedrock groundwater is evaluated on the basis of radioactive (3H, 14C) and stable (2H, 18O) isotope data, combined with chemical data, and topographic and tectonic implications of groundwater occurrence. In the coastal belt of Finland brackish and saline groundwater is trapped in fractures and shear zones, and exhibits distinct marine chemical and isotopic imprints. It represents relict seawater, mainly from the postglacial Litorina Sea phase. Inland, saline groundwater and brines occur in several diamond drill holes at depths of 300 to 1100 metres. The salinity of these waters is attributed predominantly to water-rock interaction. The uppermost water has meteoric oxygen-hydrogen isotopic compositions, whereas the most saline (Cl- some 20,000 mg/L) deep-seated groundwater plots above the global meteoric water line, like the Canadian Shield brines, indicating long residence time and low temperature equilibration with wall rocks. Geochemical and isotopic results from some localities demonstrate that the upper saline water cannot be attributed to simple mixing between fresh water and deep brines but that it was formed independently. (author)

  10. Cosmogenic 21Ne concentrations and exposure ages of summit bedrocks in the Grove Mountains,Antarctica

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Various sources of 21Ne and 22Ne exist in surface rocks:cosmogenic,in situ nucleogenic from internal U and Th,trapped crustal nucleogenic and trapped atmospheric.This paper reports the first measurement,in China,of cosmogenic 21Ne and 22Ne in surface bedrocks.We developed a unique sample pre-treatment procedure that effectively removed inclusions inside quartz grains,and thus maximally reduced nucleogenic contributions of 21Ne and 22Ne.Step-heating experiments show that concen-trations of cosmogenic 21Ne and 22Ne in summit bedrock samples R9202 and R9203 from Grove Mountains,Antarctica,are(3.83±0.87)×108 and(5.22±0.51)×108 atoms/g,respectively.The corresponding minimum exposure ages are 2.2±0.5 and 3.0±0.3 Ma.This indicates that the ice sheet in East Antarctica was uncovered the crest of Mount Harding,a typical nunatak in Grove Mountains,since at least mid-Pliocene.

  11. 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.

  12. Uranium and thorium series radionuclides in drinking water from drilled bedrock wells: correlation to geology and bedrock radioactivity and dose estimation

    International Nuclear Information System (INIS)

    Natural radioactivity in drinking water from 328 drilled wells was studied in correlation to source parameters. Poor correlation to both aquifer geology and bedrock radioactivity was observed. Concentrations of 238U, 226Ra, 222Ra, 222Rn and 210Po in groundwater samples was in the ranges -1 respectively. In about 80% of the sites the radon concentration exceeds the Nordic recommended exemption level for radon in drinking water and 15% of the sites exceed the action limit. The effective doses from ingestion were calculated and presented in association with geology. Doses due to ingestion ranged between 0.05 and 20.4 mSv.y-1, where the average contribution from 222Rn amounted to 75%. In comparison, the effective doses from inhalation of indoor 222Rn ranged between 0.2 and 20 mSv.y-1. The average contribution from inhalation of 222Rn in air to the total effective dose (ingestion+inhalation) was 58±22%, 73±18% and 77±16% (1 SD) for the age categories 1 y, 10 y and adults respectively. (author)

  13. Optimizing a Hydrogeologic Investigation of a Fractured Bedrock Aquifer With a Seismic Reflection Survey

    Science.gov (United States)

    Truskowski, M.; Warner, J.; Tisoncik, D.

    2003-12-01

    This project involves extensive investigation and focused remediation of chlorinated solvents in fractured bedrock and overlying alluvium in Northern California. Primary contaminants include 1,1,1-TCA, 1,1-DCE, and 1,1- DCA. The source area includes recoverable DNAPL, with a maximum accumulated thickness of 29 feet in a well, and dissolved concentrations in excess of 500 mg/L. The dissolved plume extends away from the source through an extensive fracture network to a depth of 450 feet. A bedrock high corresponds to the source area, with the absence of overlying sediments providing a migration pathway into the bedrock for DNAPL. The depth to bedrock and location/depth of fracture zones are highly variable across the site, with both factors significantly influencing drilling costs. The investigation involved drilling wells to depths up to 700 feet, borehole geophysics, a seismic reflection survey, and aquifer testing. The seismic reflection survey was performed to identify zones of increased fracturing, and to map the topography of the upper bedrock interface. To address the objectives of the survey, both p-wave and shear wave methods were tested in an effort to identify fracture orientation and density. A split-spread configuration with station spacing of five feet and 144 recording channels was used to collect the data for both methods. A microvibrator was used as the energy source, varying its orientation to generate p- and shear waves. Preliminary review of the test sections revealed abundant faulting, which would complicate p-/shear rotational analysis and is the likely cause of areas of increased fracturing. Based on the data quality and survey objectives, the remainder of the survey, totaling linear 6,570 feet, was collected with a p-wave source and receivers, using a 50 to 300 Hertz linear sweep. Unique aspects of the survey include a target depth of up to 1,000 feet and operational constraints associated with working in the aircraft movement area of a major

  14. 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

  15. Reduction of Long-Term Bedrock Incision Efficiency by Short-Term Alluvial Cover Intermittency

    Science.gov (United States)

    Lague, D.

    2009-12-01

    Rapid mountain river incision through bedrock is an inherently stochastic process resulting from the long-term summation of flow and sediment discharge events at very variable rates and frequency. While the actual incision processes remains difficult to apprehend in situ and are the subject of ongoing research, there is no ambiguity on the inhibiting effect of a thick alluvial cover (several meters) on bed incision. This alluvial cover thickness strongly fluctuates as a function of stochastic supply of sediment by hillslopes, modulated by sediment transport and storage in the drainage network. Here, I study how this short-term stochasticity propagates into the long-term reduction of bedrock incision efficiency (the cover effect) at geological timescales, and how the upscaled cover model compare to existing empirical models. I introduce a new numerical model (SSTRIM, Stochastic Sediment Transport and River Incision Model) that resolves sediment transport and bedrock incision at daily timescales over a channel reach consisting of several trapezoidal cross-sections linked together. The model is run for thousands of years until a steady-state geometry is reached under the prevailing uplift, sediment supply and water discharge rates. The model incorporates (i) a stochastic sediment supply mimicking the pdf of sediment volume supplied by landsliding, (ii) a transport threshold and daily stochastic variations in water discharge, (iii) a freely evolving channel width and slope; (iv) an explicit treatment of alluvial thickness variations and corresponding bed incision reduction. Bed and bank incision are calculated as a function of bed and bank shear stress. Model results predict the existence of 2 cover dynamics regime: one in which the bed is almost permanently partially covered by sediment, and on in which intermittency dominates. In this later case, the cover effect operates over long-term by modulating the proportion of time where the channel is fully or not covered

  16. 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

  17. Long-term geoelectrical monitoring of laboratory freeze-thaw experiments on bedrock samples

    Science.gov (United States)

    Kuras, Oliver; Uhlemann, Sebastian; Murton, Julian; Krautblatter, Michael

    2014-05-01

    Much attention has recently focussed on the continuous and near-real-time geophysical monitoring of permafrost-affected bedrock with permanently installed sensor arrays. It is hoped that such efforts will enhance process understanding in such environments (permafrost degradation, weathering mechanisms) and augment our capability to predict future instabilities of rock walls and slopes. With regard to electrical methods for example, recent work has demonstrated that temperature-calibrated electrical resistivity tomography (ERT) is capable of imaging recession and re-advance of rock permafrost in response to the ambient temperature regime. However, field experience also shows that several fundamental improvements to ERT methodology are still required to achieve the desired sensitivity, spatial-temporal resolution and long-term robustness that must underpin continuous geophysical measurements. We have applied 4D geoelectrical tomography to monitoring laboratory experiments simulating permafrost growth, persistence and thaw in bedrock over a period of 26 months. Six water-saturated samples of limestone and chalk of varying porosity represented lithologies commonly affected by permafrost-related instability. Time-lapse imaging of the samples was undertaken during multiple successive freeze-thaw cycles, emulating annual seasonal change over several decades. Further experimental control was provided by simultaneous measurements of vertical profiles of temperature and moisture content within the bedrock samples. These experiments have helped develop an alternative methodology for the volumetric imaging of permafrost bedrock and tracking active layer dynamics. Capacitive resistivity imaging (CRI), a technique based upon low-frequency, capacitively-coupled measurements emulates ERT methodology, but without the need for galvanic contact on frozen rock. The latter is perceived as a key potential weakness, which could lead to significant limitations as a result of the variable

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

    International Nuclear Information System (INIS)

    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 m2/s or 1.3 x 10-6 m2/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 4000

  19. 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

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

    International Nuclear Information System (INIS)

    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 m2/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 history of

  1. Processes of bedrock groundwater seepage and their effects on soil water fluxes in a foot slope area

    Science.gov (United States)

    Masaoka, Naoya; Kosugi, Ken'ichirou; Yamakawa, Yosuke; Tsutsumi, Daizo

    2016-04-01

    The impact of bedrock groundwater seepage on surface hydrological processes in a foot slope area is an important issue in hillslope hydrology. However, properties of water flux vectors around a seepage area are poorly understood because previous studies have lacked sufficient spatial resolution to capture detailed water movements. Here, we conducted hydrometric observations using unprecedented high-resolution and three-dimensional tensiometer nests in the mountainous foot slope area of the Hirudani experimental basin (Japan). Our findings are summarized as follows: (1) a considerable quantity of groundwater seeped from the bedrock surface in the study site. A groundwater exfiltration flux occurred constantly from a seepage area regardless of rainfall conditions. Saturated lateral flow over the bedrock surface occurred constantly in the region downslope of the seepage area. Groundwater was likely to mixed with soil water infiltration and flowed toward the lower end of the slope. (2) During the wet season, the seepage area expanded ∼3 m in the upslope direction along the bedrock valley in a single season. (3) The pressure head waveform observed in the seepage area showed gradual and significant increases after large rainfall events. However, the seepage pressure propagated within a relatively narrow area: a slope distance of ∼4 m from the seepage point in the downslope direction due to the damping of seepage pressure. (4) Within the whole study area, groundwater seeped from a narrow area located at the bottom of the valley line of the bedrock surface. The shape of the seepage area changed along the valley line in the wet season. Overall, we reveal spatial and temporal variations in bedrock groundwater seepage under the soil mantle and the effects on soil water fluxes. These findings should improve the accuracy of models for predicting surface hydrogeomorphological processes in mountainous hillslopes.

  2. Effect of bedrock permeability on stream base flow mean transit time scaling relations: 1. A multiscale catchment intercomparison

    Science.gov (United States)

    Hale, V. Cody; McDonnell, Jeffrey J.

    2016-02-01

    The effect of bedrock permeability and underlying catchment boundaries on stream base flow mean transit time (MTT) and MTT scaling relationships in headwater catchments is poorly understood. Here we examine the effect of bedrock permeability on MTT and MTT scaling relations by comparing 15 nested research catchments in western Oregon; half within the HJ Andrews Experimental Forest and half at the site of the Alsea Watershed Study. The two sites share remarkably similar vegetation, topography, and climate and differ only in bedrock permeability (one poorly permeable volcanic rock and the other more permeable sandstone). We found longer MTTs in the catchments with more permeable fractured and weathered sandstone bedrock than in the catchments with tight, volcanic bedrock (on average, 6.2 versus 1.8 years, respectively). At the permeable bedrock site, 67% of the variance in MTT across catchments scales was explained by drainage area, with no significant correlation to topographic characteristics. The poorly permeable site had opposite scaling relations, where MTT showed no correlation to drainage area but the ratio of median flow path length to median flow path gradient explained 91% of the variance in MTT across seven catchment scales. Despite these differences, hydrometric analyses, including flow duration and recession analysis, and storm response analysis, show that the two sites share relatively indistinguishable hydrodynamic behavior. These results show that similar catchment forms and hydrologic regimes hide different subsurface routing, storage, and scaling behavior—a major issue if only hydrometric data are used to define hydrological similarity for assessing land use or climate change response.

  3. Stratified basal diamicts and their implications for subglacial conditions in deeply incised bedrock troughs

    Science.gov (United States)

    Buechi, Marius W.; Menzies, John; Anselmetti, Flavio S.

    2016-04-01

    Deep bedrock troughs ("tunnel valleys"), formed below Pleistocene piedmont glaciers, serve as valuable archives of the Quaternary landscape evolution of the Northern Alpine foreland basin. The sedimentary infill of these troughs is often dominated by glacier retreat deposits (e.g. glacio-lacustrine silts), while the context of diamicts and gravels at the base, i.e. directly overlying bedrock, remain controversial with regard to their deposition in a subglacial or proglacial environment. We present results from a set of drill cores that recovered such coarse-grained basal units in a major buried bedrock-trough system in the Lower Glatt Valley, Northern Switzerland. The excellent core recovery has allowed a detailed lithological study combining macroscopic, microscopic and geochemical methods. The macroscopic analysis revealed that the basal infill comprises diamicts segmented into ~1-3 m thick layers by sorted interbeds. These interbeds consist either of i) clast-supported gravels interpreted as bedload or lag deposits, or ii) laminated sands and silts representing deposition dominated by low-energy settling. The thinly spaced stacking of sorted and stratified sediments results in a high vertical facies variability. The distinct changes in the energy levels at which the sorted interbeds were transported and deposited are interpreted to indicate alternating phases of a decoupled and coupled ice-bed-interface at the base of the overdeepening. This interpretation is supported by the microstructural analysis performed on thin-sections from diamictons of the basal unit, which reveal a polyphase (brittle and ductile) deformation of the diamicts. A primary indication for a subglacial origin of the deformation comes from an abundance of crushed grains, interpreted as resulting from in-situ fracturing of grains under high tensile stresses, typically attained at grain-to-grain contacts during subglacial deformation. Such a signature is unlikely to occur in a proglacial

  4. 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

  5. Geologic Controls on Groundwater Flow and Contaminant Transport in Fractured Bedrock

    Science.gov (United States)

    Warner, J.; Truskowski, M.; Fieber, L.; Ernstmann, G.; Tisoncik, D.; Wells, T.; Stanhope, J.; Henrich, B.

    2003-12-01

    This project involves strategic hydrogeologic investigation and remediation of chlorinated solvents in fractured bedrock and overlying alluvium in Northern California. Primary contaminants include 1,1,1-TCA, 1,1-DCE and 1,1- DCA. The source area includes recoverable DNAPL, with a maximum accumulated thickness of 29 feet in a well, and dissolved concentrations in excess of 500 mg/L. The dissolved plume extends away from the source through an extensive fracture network to a depth of 450 feet. The investigation involved drilling monitoring wells to depths up to 700 feet, borehole geophysics, a seismic reflection survey, and aquifer testing. Optical and acoustic televiewer logging were used to map the fracture network, which is dominated by west, southwest, south, and east dipping features. The seismic reflection survey identified en-echelon, southeast dipping normal faults and antithetic, southwest dipping reverse faults that are generally consistent with the orientation of structures in the nearby San Andreas fault zone. The primary fault strikes are generally parallel to those of the dominant fracture sets. Notable lithologic discontinuities in the Franciscan bedrock were documented across major faults, possibly related to significant vertical and strike-slip offset. The seismic reflection survey provided a useful guide for drilling by predicting areas of higher fracture density. Slug tests and acoustic wave-form, conductivity, temperature, and static/dynamic heat pulse flow meter logging were used to establish that flow is primarily through the fractures and conductive portions of the alluvium. These data were used to install an effective multilevel well network, establish a ground water flow pattern that reflects geologic controls and regional gradient, and support remediation evaluations. Remediation evaluations include dissolved phase remediation bench tests, DNAPL recovery, and monitored natural attenuation (MNA). The dissolved phase bench tests are in progress

  6. Landscape evolution and bedrock incision in the northern Alpine Foreland since the last 2 Ma

    Science.gov (United States)

    Claude, Anne; Akçar, Naki; Schlunegger, Fritz; Ivy-Ochs, Susan; Kubik, Peter; Christl, Marcus; Vockenhuber, Christof; Dehnert, Andreas; Kuhlemann, Joachim; Rahn, Meinert; Schlüchter, Christian

    2016-04-01

    The landscape evolution of the Swiss Alpine Foreland since the early Pleistocene is of utmost importance for modelling the long-term safety of deep geological repositories for nuclear waste disposal in the northern Alpine Foreland. The oldest Quaternary sediments in the northern foreland are proximal glaciofluvial sediments lying unconformably on Tertiary Molasse or Mesozoic carbonate bedrock. These deposits form topographically distinct and discontinuous isolated plateaus. Terrace morphostratigraphy has a reversed stratigraphic relationship, i.e. today older sediments are located at higher altitudes and vice versa. In this study, we focus on the landscape evolution and long-term bedrock incision in the Swiss Alpine Foreland. We reconstruct the terrace chronology in the foreland at six key locations at different altitudes ranging from 433 m a.s.l. to 675 m a.s.l. by applying cosmogenic depth-profile and isochron-burial dating techniques. First results from these sites indicate that the gravels at studied sites were accumulated in the foreland between 1 and 2 Ma. Based on this reconstructed chronology, long-term bedrock incision rates between 0.1 and 0.2 mm/a were calculated. Thus, we inferred a landscape at that time that was most likely characterized by smoother hillslopes than at present. During the Mid-Pleistocene Revolution (ca. 0.95 Ma), a re-organization of the drainage systems occurred in the Alpine Foreland with a significant lowering of the base level of stream channels. Existing data suggest slightly increased incision rates after this drainage network re-organisation compared to our results. The reconstruction of the chronology at the remaining sites may allow quantifying a pronounced incision as well as the exact timing of the acceleration in the incision rates. REFERENCES Heuberger, S. & Naef, H. (2014). NAB 12-35: Regionale GIS-Kompilation und -Analyse der Deckenschotter-Vorkommen im nördlichen Alpenvorland. Nagra Arbeitsbericht. Kuhlemann, J. & Rahn

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

    Energy Technology Data Exchange (ETDEWEB)

    Cascoyne, M. [Gascoyne GeoProjects Inc. (Canada)

    2000-06-01

    formed on freezing 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{sub 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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Gascoyne, M. [Gascoyne GeoProjects Inc., Pinawa (Canada)

    2000-04-01

    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{sub 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.

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

    International Nuclear Information System (INIS)

    , 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 SO4-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

  10. Bedrock geologic map of the Seward Peninsula, Alaska, and accompanying conodont data

    Science.gov (United States)

    Till, Alison B.; Dumoulin, Julie A.; Werdon, Melanie B.; Bleick, Heather A.

    2011-01-01

    This 1:500,000-scale geologic map depicts the bedrock geology of Seward Peninsula, western Alaska, on the North American side of the Bering Strait. The map encompasses all of the Teller, Nome, Solomon, and Bendeleben 1:250,000-scale quadrangles, and parts of the Shishmaref, Kotzebue, Candle, and Norton Bay 1:250,000-scale quadrangles (sh. 1; sh. 2). The geologic map is presented on Sheet 1. The pamphlet includes an introductory text, detailed unit descriptions, tables of geochronologic data, and an appendix containing conodont (microfossil) data and a text explaining those data. Sheet 2 shows metamorphic and tectonic units, conodont color alteration indices, key metamorphic minerals, and locations of geochronology samples listed in the pamphlet. The map area covers 74,000 km2, an area slightly larger than West Virginia or Ireland.

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

    International Nuclear Information System (INIS)

    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 SO4-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.)

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

    International Nuclear Information System (INIS)

    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 -3 m2/s to 1*10-7 m2/s, the average being 1-10-5 m2/s. (orig.)

  13. Development of an overpack for the storage of high-level waste in Swiss granitic bedrock

    International Nuclear Information System (INIS)

    Current programs aimed at demonstrating the feasibility of safe final disposal of high-level nuclear waste in Switzerland envisage a repository in the crystalline bedrock of the north of the country. The groundwater is reducing, with a mineralization of typically 10 g·L-1. The corrosion studies carried out in Switzerland have shown that unalloyed steel is a suitable overpack material under the conditions expected in the repository. The necessary corrosion allowance for a lifetime of 1000 years is 50 mm. Design work, based on the use of a typical cast steel with a tensile strength of 400 MN·m-2, has led to a reference overpack concept for a disposal of vitrified HLW. This reference overpack is designed as a self-shielding, self-supporting, cylindrical shell with hemispherical ends. 16 refs

  14. Review of DOE's proposal for Crystalline bedrock disposal of radioactive waste, north-central area

    International Nuclear Information System (INIS)

    The DOE's Region-to-Area Screening Methodology for the Crystalline Repository Project (DOE/CH-1), the Final North-Central Region Geologic Characterization Report (DOE/CH-8(1)), and the Draft Area Recommendation Report for the Crystalline Repository Project (DOE/CH-15), with the associated maps, were reviewed. The review has focused on all general information regarding geologic topics and all site-specific data for DOE sites NC-10 and NC-3. This report contains two parts: (1) a point-by-point critique of perceived errors, omissions, or other shortcomings in each of the three documents; and (2) a discussion of the feasibility of crystalline bedrock as a suitable host medium for high-level radioactive waste

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

    International Nuclear Information System (INIS)

    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

  16. Borehole Flow and Contaminant Distribution in Sedimentary-Bedrock Recharge Areas

    Science.gov (United States)

    Williams, J. H.

    2005-12-01

    Borehole flow and contaminant distribution has been investigated at a series of VOC-impacted sites in New York, New Jersey, and California that are recharge areas for sandstone, mudstone, and carbonate-bedrock aquifers. At the investigated sites, downward flow occurs through open boreholes that intersect shallow and deep fracture zones having differing hydraulic heads. Detected flows span the dynamic measurement range of 0.03 to 30 liters per minute for high-resolution flowmeters that employ heat-pulse and electromagnetic technologies. Estimated head differences between shallow and deep zones from model simulation of ambient and stressed flow profiles range from one to more than 10 meters, and are in close agreement with differences measured between zones isolated by straddle packers or by multiple-depth well completions. The presence of boreholes that are open temporarily during installation or completed as open holes impacts contaminant distribution and adversely affects the results of ground-water quality sampling programs. In boreholes open to shallow contaminated zones and deep non-contaminated zones, ambient flow diverts dissolved VOCs from the shallow zones down the borehole and into the deep zones. Samples obtained from such boreholes at purge and sampling rates less than the ambient downward flow represent the water quality of the shallow zones regardless of the depths where samples are collected. This can lead to the erroneous interpretation of a deep contaminant plume. Sampling by use of straddle-packer systems with low purge and sampling rates and short-term zone isolation also may indicate deep contamination because of inadequate flushing. Even in deep zones isolated by multiple-depth completions, elevated VOC concentrations linger for many months because of contaminant diffusion into and out of the bedrock matrix. Conversely, in boreholes open to shallow non-contaminated zones and deep contaminated zones, samples collected at rates less than the

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

    International Nuclear Information System (INIS)

    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.)

  18. Mineral deformation and subglacial processes on ice-bedrock interface of Hailuogou Glacier

    Institute of Scientific and Technical Information of China (English)

    LIU GengNian; CHEN YiXin; ZHANG Yue; FU HaiRong

    2009-01-01

    Hailuogou Glacier is located in a warm and humid maritime environment. It is large and moves very fast.The bottom of the glacier slides intensively and the temperature at the bottom approaches the pressure melting point. Therefore,there are abundant melting water and debris which act as effective "grinding tools"for glacial abrasion. Polarizing microscope is used to observe the mineral deformation characteristics on the ice-bedrock interface. It is found that feldspar,quartz,hornblende and biotite are exposed to deformation,fracture and chemical alteration to various extents. Bending deformation is common for biotite,due to their lattice characteristics,and the bending orientations are mostly the same as the glacier flow. Bending deformation also occurs in a few hornblendes. High-angle tension fracture and low-angle shear fracture are common for quartz and feldspar,some of them are totally crushed (mylonizations) due to their rigidity. Thus,all the abrasion,quarrying,subglacial water action and subglacial dissolution processes at the bottom of the glacier are verified at the micro-scale level.Mineral deformation and fracture are the basic subglacial erosion mechanisms. The abrasion thickness is 30-90 μm for each time and the average is 50 μm. Most of the debris are silt produced by glacial abrasion. The extent of mineral deformation and fracture decreases drastically downwards beneath the bedrock surface. The estimated erosion rate is about 2.2-11.4 mm/a,which is similar to that of other maritime alpine glaciers,smaller than that of large-scale piedmont glaciers In Alaska (10-30 mm/a),and larger than that of continental glaciers (0.1-1.0 mm/a). The type and size of a glacier are the main factors that influence its erosion rate.

  19. Island Formation through Bar Deposition and Channel Cutoff in the Bedrock Controlled South River, Virginia

    Science.gov (United States)

    Jurk, D.; Pizzuto, J. E.

    2010-12-01

    Islands in braided and meandering alluvial channels form by bar accretion and channel cutoff, however, island formation in bedrock-controlled channels is poorly understood. The South River is a single-thread, sinuous, gravel-bed, bedrock river. It is neither meandering nor braided but aerial photographs show the development of gravel bars and the formation of islands that have formed through channel cutoff. This study deciphers processes that lead to both types of island formation and their role in the channel morphology of the South River. The South River was analyzed using aerial photographs and work in the field provided additional data that were used to identify islands and their properties. A Geographic Information System (GIS) was used to evaluate historical aerial photographs dating back to 1937 for location, morphology, origin, and development of islands along an approximately 40 km study reach. Field studies included the surveying of cross sections to determine elevations of islands relative to neighboring floodplains, as well as pebble counts and cores to define sediment characteristics. Aerial photographs indicate that six islands had formed before and an additional 12 islands formed after 1937, placing the average island formation frequency at 0.005 islands per km per year since 1937. Field data indicate that elevation, grain size, stratigraphy, and vegetation of some islands closely resemble those of the floodplains supporting the hypothesis that those islands formed through cutoff, while one island’s sediment was similar to that of the channel and did not show similarities to floodplains or any other islands indicating formation through in-channel sediment deposition. Studies of bank erosion rates along the South River demonstrate that 33% of bank erosion along the South River occurs in divided reaches of the channel associated with islands. Understanding the formation and evolution of these islands may allow for an accurate prediction of future

  20. Surficial and bedrock geology beneath the Strait of Belle Isle in the vicinity of a proposed power-cable crossing

    Energy Technology Data Exchange (ETDEWEB)

    Woodworth-Lynas, C.M.T.; Guigne, J.Y.; King, E.L.

    1992-01-01

    A review is presented of geological, geophysical, and engineering studies carried out on the feasibility of installing high-voltage dc submarine cables beneath the Strait of Belle Isle for the purpose of transmitting hydroelectric power from Labrador to Newfoundland. New interpretations are included with respect to nomenclature of bedrock units and their distribution, adding to the knowledge of glacial history of the Strait based on the surficial geology and the existence of exposed suites of ribbed moraines. Information on subsurface bedrock geology has been derived almost entirely from borehole information; appraisal of deep seismic-reflection data from 1973-75 shows the data are poor in quality, preventing reliable interpretation. Four acoustically defined surficial geology units have been recognized. Only 15 iceberg scours have been positively identified from sidescan sonograms, but this seems anomalously low. It is noted that icebergs can scour in water depths to 105 m, and may also scour both upslope and downslope. This means that bathymetric sheltering may not prevent scouring icebergs from reaching potential cable routes. Three cable design concepts are considered: installation in an 18.28 km tunnel in bedrock 580 m below sea level; laying cables on the sea floor between two bedrock tunnels extending from shore to the 85 m isobath; and installing cables in trenches on the sea floor. 145 refs., 21 figs., 5 tabs.

  1. 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…

  2. Hydraulic relationships between buried valley sediments of the glacial drift and adjacent bedrock formations in northeastern Ohio, USA

    Science.gov (United States)

    Seyoum, Wondwosen Mekonnen; Eckstein, Yoram

    2014-08-01

    Buried valleys are ancient river or stream valleys that predate the recent glaciation and since have been filled with glacial till and/or outwash. Outwash deposits are known to store and transmit large amounts of groundwater. In addition to their intrinsic hydraulic properties, their productivity depends on their hydraulic relationships with the adjacent bedrock formations. These relationships are examined using a steady-state three-dimensional groundwater flow model through a section of a buried valley in northeastern Ohio, USA. The flow domain was divided into five hydrostratigraphic units: low-conductivity (K) till, high-K outwash, and three bedrock units (Pottsville Formation, Cuyahoga Group and Berea Sandstone). The model input was prepared using the data from well logs and drilling reports of residential water wells. The model was calibrated using observed heads with mean residual head error of 0.3 m. The calibrated model was used to quantify flux between the buried valley and bedrock formations. Mass balance was calculated to within an error of 2-3 %. Mass balance of the buried valley layer indicates that it receives 1.6 Mm3/year (≈40 % of the total inflow) from the adjacent bedrock aquifers: Pottsville Formation contributes 0.96 Mm3/year (60 %) while the Berea Sandstone 0.64 Mm3/year (40 %).

  3. Environmental quality and preservation; bedrock beneath reefs; the importance of geology in understanding biological decline in a modern reef ecosystem

    Science.gov (United States)

    Lidz, Barbara H.

    2000-01-01

    Environmental Quality and Preservation-Bedrock Beneath Reefs: the Importance of Geology in Understanding Biological Decline in a Modern Ecosystem' is a four-page and one-plate full-color discussion of the geologic framework and evolutionary history of the coral reef ecosystem that lines the outer shelf off the Florida Keys.

  4. Biogeochemistry of the Transition Elements in a Forested Landscape (beech, Fagus sylvatica L.) with the Granite Bedrock

    Czech Academy of Sciences Publication Activity Database

    Minařík, Luděk; Skřivan, Petr; Žigová, Anna; Bendl, J.

    2000-01-01

    Roč. 12, - (2000), s. 7-17. ISSN 1210-9606 R&D Projects: GA AV ČR IAA3013603; GA ČR GA205/96/0011 Keywords : transition elements * granite bedrock * soil profile Subject RIV: DD - Geochemistry http://geolines.gli.cas.cz/fileadmin/volumes/volume12/G12-007.pdf

  5. Geochemistry of highly acidic mine water following disposal into a natural lake with carbonate bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Wisskirchen, Christian, E-mail: ChristianWisskirchen@web.de [Institute of Mineralogy and Geochemistry, University of Lausanne, CH-1015 Lausanne (Switzerland); Dold, Bernhard [Institute of Mineralogy and Geochemistry, University of Lausanne, CH-1015 Lausanne (Switzerland)] [Instituto de Geologia Economica Aplicada, Universidad de Concepcion, Concepcion (Chile); Friese, Kurt [UFZ - Helmholtz Centre for Environmental Research, Department of Lake Research, D-39114 Magdeburg (Germany); Spangenberg, Jorge E. [Institute of Mineralogy and Geochemistry, University of Lausanne, CH-1015 Lausanne (Switzerland); Morgenstern, Peter [UFZ - Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, D-04318 Leipzig (Germany); Glaesser, Walter [Institute of Geophysics and Geology, University of Leipzig, D-04211 Leipzig (Germany)

    2010-08-15

    Research highlights: {yields} Mean lake water element composition did not differ greatly from discharged AMD. {yields} Most elements showed increasing concentrations from the surface to lake bottom. {yields} Jarosite formed in the upper part, settled, and dissolved in the deeper part of the lake. {yields} Elements migrated into the underlying carbonates in the sequence As< Pb {approx} Cu < Cd < Zn = Mn. {yields} Gypsum and hydroxide precipitation had not resulted in complete clogging of the lake bedrocks. - Abstract: Acid mine drainage (AMD) from the Zn-Pb(-Ag-Bi-Cu) deposit of Cerro de Pasco (Central Peru) and waste water from a Cu-extraction plant has been discharged since 1981 into Lake Yanamate, a natural lake with carbonate bedrock. The lake has developed a highly acidic pH of {approx}1. Mean lake water chemistry was characterized by 16,775 mg/L acidity as CaCO{sub 3}, 4330 mg/L Fe and 29,250 mg/L SO{sub 4}. Mean trace element concentrations were 86.8 mg/L Cu, 493 mg/L Zn, 2.9 mg/L Pb and 48 mg/L As, which did not differ greatly from the discharged AMD. Most elements showed increasing concentrations from the surface to the lake bottom at a maximal depth of 41 m (e.g. from 3581 to 5433 mg/L Fe and 25,609 to 35,959 mg/L SO{sub 4}). The variations in the H and O isotope compositions and the element concentrations within the upper 10 m of the water column suggest mixing with recently discharged AMD, shallow groundwater and precipitation waters. Below 15 m a stagnant zone had developed. Gypsum (saturation index, SI {approx} 0.25) and anglesite (SI {approx} 0.1) were in equilibrium with lake water. Jarosite was oversaturated (SI {approx} 1.7) in the upper part of the water column, resulting in downward settling and re-dissolution in the lower part of the water column (SI {approx} -0.7). Accordingly, jarosite was only found in sediments from less than 7 m water depth. At the lake bottom, a layer of gel-like material ({approx}90 wt.% water) of pH {approx}1 with a

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

    International Nuclear Information System (INIS)

    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

  7. The Natural Terrestrial Carbon Sequestration Potential of Rocky Mountain Soils Derived From Volcanic Bedrock

    Science.gov (United States)

    Yager, D. B.; Burchell, A.; Johnson, R. H.

    2008-12-01

    The possible economic and environmental ramifications of climate change have stimulated a range of atmospheric carbon mitigation actions, as well as, studies to understand and quantify potential carbon sinks. However, current carbon management strategies for reducing atmospheric emissions underestimate a critical component. Soils represent between 18 - 30% of the terrestrial carbon sink needed to prevent atmospheric doubling of CO2 by 2050 and a crucial element in mitigating climate change, natural terrestrial sequestration (NTS), is required. NTS includes all naturally occurring, cumulative, biologic and geologic processes that either remove CO2 from the atmosphere or prevent net CO2 emissions through photosynthesis and microbial fixation, soil formation, weathering and adsorption or chemical reactions involving principally alumino- ferromagnesium minerals, volcanic glass and clays. Additionally, NTS supports ecosystem services by improving soil productivity, moisture retention, water purification and reducing erosion. Thus, 'global climate triage' must include the protection of high NTS areas, purposeful enhancement of NTS processes and reclamation of disturbed and mined lands. To better understand NTS, we analyzed soil-cores from Colorado, Rocky Mountain Cordillera sites. North-facing, high-plains to alpine sites in non-wetland environments were selected to represent temperate soils that may be less susceptible to carbon pool declines due to global warming than soils in warmer regions. Undisturbed soils sampled have 2 to 6 times greater total organic soil carbon (TOSC) than global TOSC averages (4 - 5 Wt. %). Forest soils derived from weathering of intermediate to mafic volcanic bedrock have the highest C (34.15 Wt. %), C:N (43) and arylsulfatase (ave. 278, high 461 μg p-nitrophenol/g/h). Intermediate TOSC was identified in soils derived from Cretaceous shale (7.2 Wt. %) and Precambrian, felsic gneiss (6.2 Wt. %). Unreclaimed mine-sites have the lowest C (0

  8. 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

  9. Activity and diversity of methane-oxidizing bacteria in glacier forefields on siliceous and calcareous bedrock

    Directory of Open Access Journals (Sweden)

    P. A. Nauer

    2012-01-01

    Full Text Available The global methane (CH4 cycle is largely driven by methanogenic archaea and methane-oxidizing bacteria (MOB, but little is known about their activity and diversity in pioneer ecosystems. We conducted a field survey in forefields of 13 receding Swiss glaciers on both siliceous and calcareous bedrock to investigate and quantify CH4 turnover based on soil-gas CH4 concentration profiles, and to characterize MOB communities using pmoA sequencing and T-RFLP. Methane turnover was fundamentally different in the two bedrock categories. Of the 36 CH4 concentration profiles from siliceous locations, 11 showed atmospheric CH4 consumption at concentrations of ∼1–2 μl l−1 with soil-atmosphere CH4 fluxes of −0.14 to −1.1 mg m−2 d−1. Another 11 profiles showed no apparent activity, while the remaining 14 exhibited slightly increased CH4 concentrations of ∼2–10 μl l−1, most likely due to microsite methanogenesis. In contrast, all profiles from calcareous sites suggested a substantial, yet unknown CH4 source below our sampling zone, with soil-gas CH4 concentrations reaching up to 1400 μl l−1. Remarkably, most soils oxidized ∼90% of the deep-soil CH4, resulting in soil-atmosphere fluxes of 0.12 to 31 mg m−2 d−1. MOB showed limited diversity in both siliceous and calcareous forefields: all identified pmoA sequences formed only 5 OTUs and, with one exception, could be assigned to either Methylocystis or the as-yet-uncultivated Upland Soil Cluster γ (USCγ. The latter dominated T-RFLP patterns of all siliceous and most calcareous samples, while Methylocystis dominated in 4 calcareous samples. As Type I MOB are widespread in cold climate habitats with elevated CH4 concentrations, USCγ might be the corresponding

  10. Activity and diversity of methane-oxidizing bacteria in glacier forefields on siliceous and calcareous bedrock

    Directory of Open Access Journals (Sweden)

    P. A. Nauer

    2012-06-01

    Full Text Available The global methane (CH4 cycle is largely driven by methanogenic archaea and methane-oxidizing bacteria (MOB, but little is known about their activity and diversity in pioneer ecosystems. We conducted a field survey in forefields of 13 receding Swiss glaciers on both siliceous and calcareous bedrock to investigate and quantify CH4 turnover based on soil-gas CH4 concentration profiles, and to characterize the MOB community by sequencing and terminal restriction fragment length polymorphism (T-RFLP analysis of pmoA. Methane turnover was fundamentally different in the two bedrock categories. Of the 36 CH4 concentration profiles from siliceous locations, 11 showed atmospheric CH4 consumption at concentrations of ~1–2 μL L−1 with soil-atmosphere CH4 fluxes of –0.14 to –1.1 mg m−2 d−1. Another 11 profiles showed no apparent activity, while the remaining 14 exhibited slightly increased CH4 concentrations of ~2–10 μL L−1 , most likely due to microsite methanogenesis. In contrast, all profiles from calcareous sites suggested a substantial, yet unknown CH4 source below our sampling zone, with soil-gas CH4 concentrations reaching up to 1400 μL L−1. Remarkably, most soils oxidized ~90 % of the deep-soil CH4, resulting in soil-atmosphere fluxes of 0.12 to 31 mg m−2 d−1. MOB showed limited diversity in both siliceous and calcareous forefields: all identified pmoA sequences formed only 5 operational taxonomic units (OTUs at the species level and, with one exception, could be assigned to either Methylocystis or the as-yet-uncultivated Upland Soil Cluster γ (USCγ. The latter dominated T-RFLP patterns of all siliceous and most calcareous samples, while Methylocystis dominated in 4 calcareous samples. Members of Upland Soil

  11. Preconditioning of the Eibsee rock avalanche by deglaciation and development of critical bedrock stresses

    Science.gov (United States)

    Leith, Kerry; Hofmayer, Felix; Kessler, Barbara; Krautblatter, Michael

    2016-04-01

    The impact of glacier retreat on rock slope instability since the Last Glacial Maximum is the subject of ongoing debate. Rock slope activity since ice retreat is typically attributed to increased kinematic freedom as a result of erosion during glaciation, debuttressing of valley walls which may have been supported by glacier ice, specific patterns of Holocene seismicity, or an exposure of rock slopes to increased chemical and biological weathering during the present interglacial. Here, rather than looking for a particular driver or trigger for rock slope instability, we evaluate the potential for rock mass degradation in response to an increase in tensile stress or micro-cracking in critically stressed near-surface bedrock (0 - 2 km depth). Instead of focusing on a specific driver, this allows us to identify regions in which fracture development is likely to be ongoing, and slope stability is therefore decreasing with time. Combining two orthogonal cross-sections, we evaluate stress changes and fracture development in the Zugspitze region of the Wetterstein Mountains (southern Germany) using an elasto-plastic 2-D FEM model (Phase2 from Rocscience). Based on geological evidence, we reconstruct the 3-D topography of the former Zugspitze peak, prior to what we estimate to be a 165 Mm3 collapse (previously dated at 3700 B.P.). We then impose initial stress conditions consistent with the tectonic and exhumation history of the region, as well as rock mechanical attributes derived from a fracture survey of the Zugspitzplatt and results of standard laboratory testing of Wettersteinkalk, the dominant lithology in the region. By imposing ice loading through a series of glacial-interglacial cycles, we are able to generate, and maintain critical stresses and low levels of fracture propagation beneath the Zugspitzplatt and at the location of the rock avalanche release throughout deglaciation, supporting our field observations. We then simulate weathering near the model surface

  12. 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

  13. The impact of igneous bedrock weathering on the Mo isotopic composition of stream waters: Natural samples and laboratory experiments

    Science.gov (United States)

    Voegelin, Andrea R.; Nägler, Thomas F.; Pettke, Thomas; Neubert, Nadja; Steinmann, Marc; Pourret, Olivier; Villa, Igor M.

    2012-06-01

    River waters have been shown to be systematically enriched in the heavy molybdenum (Mo) isotopes when compared to typical granites and basalts, which generally possess Mo isotopic compositions (δMo) of around 0‰. This inconsistency has been used to argue against weathering of crustal rocks as the cause for heavy riverine δMo signatures. Incongruent dissolution of primary bedrock, however, may be an important process by which the anomalous Mo signatures of the river dissolved load are produced. This study therefore investigates the effect of igneous crustal rock weathering on the aquatic δMo signal by comparing stream water and bedrock Mo isotope data to results of bulk rock leach experiments. For this purpose, stream water and bedrock (orthogneiss, granite, basalt), as well as soil and vegetation samples were collected in a small catchment in the French Massif Central. In accordance with the results of earlier studies on riverine Mo, both streams are isotopically heavier (δMo = 0.5-1.1‰) than the typical granites and basalts. The excellent agreement of these data with those of Mo released during experimental leaching of the basalt bedrock (0.6-1.0‰) identifies a predominance of basalt weathering over the stream water Mo geochemistry, while other processes (i.e. soil formation, secondary mineral precipitation and adsorption) are subordinate in this catchment. Given that the basalt bulk rock δMo reflects a value typical for crustal magmatic rocks (ca. 0.1‰), Mo isotope fractionation during the incongruent dissolution of basalt can explain the observed isotopically heavy aquatic Mo signatures. Laser ablation analyses demonstrate that the volumetrically minor magmatic sulfides can be highly enriched in Mo and mass balance calculations identify the sulfide melt inclusions as the principal Mo source for the leach solutions. These data suggest that the magmatic sulfides possess a distinctly heavier δMo signature than the coexisting silicate melt. In this

  14. 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.

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

    International Nuclear Information System (INIS)

    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.)

  16. Technical assessment of the bedrock waste storage at the Savannah River Plant

    International Nuclear Information System (INIS)

    An assessment of the safety and feasibility of ultimate storage of radioactive wastes produced at the Savannah River Plant (SRP) in horizontal tunnels excavated in the bedrock beneath the plant site is presented. Results indicate that a cavern with an excavated volume of 130 million gallons could contain 80 million gallons of concentrated radioactive SRP wastes with minimal risks if the cavern is located in the impermeable Triassic Basin underlying the Savannah River site. The cavern could be placed so that it would lie wholly within the boundaries of the plantsite. The document summarizes the general geological, hydrological, and chemical knowledge of the geological structures beneath the plantsite; develops evaluation guidelines; and utilizes mathematical models to conduct risk analyses. The risk models are developed from known soil and salt solution mechanics; from past, present, and future geological behavior of the onsite rock formations; and from known waste handling technology. The greatest risk is assessed to exist during transfer of the radioactive wastes to the cavern. When the cavern is filled and sealed, further population risks are asessed to be very low

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

    Directory of Open Access Journals (Sweden)

    M. Ramos

    2008-03-01

    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 quartzite outcrop 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 seasons of 2000 to 2005, and (ii the warming periods of the thaw seasons of 2002–2003, 2003–2004 and 2004–2005, were studied. In this modelling approach, heat gains and losses across ground surface are considered to be the causes for the 0°C isotherm movement. A methodological approach to calculate the Enthalpy change based on the thermodynamic analysis of the ground during the cooling and warming periods is proposed. The Enthalpy change 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 is considered to be constant in the borehole and initial isothermal conditions at 0°C are assumed to run the model. The final stages correspond to the temperatures at the end of the cooling and warming periods (annual minima and maxima.

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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

  20. Hydraulic model calibration for extreme floods in bedrock-confined channels: case study from northern Thailand

    Science.gov (United States)

    Kidson, R. L.; Richards, K. S.; Carling, P. A.

    2006-02-01

    Palaeoflood reconstructions based on stage evidence are typically conducted in data-poor field settings. Few opportunities exist to calibrate the hydraulic models used to estimate discharge from this evidence. Consequently, an important hydraulic model parameter, the roughness coefficient (e.g. Manning's n), is typically estimated by a range of approximate techniques, such as visual estimation and semi-empirical equations. These techniques contribute uncertainty to resulting discharge estimates, especially where the study reach exhibits sensitivity in the discharge-Manning's n relation. We study this uncertainty within a hydraulic model for a large flood of known discharge on the Mae Chaem River, northern Thailand. Comparison of the calibrated Manning's n with that obtained from semi-empirical equations indicates that these underestimate roughness. Substantial roughness elements in the extra-channel zone, inundated during large events, contribute significant additional sources of flow resistance that are captured neither by the semi-empirical equations, nor by existing models predicting stage-roughness variations. This bedrock channel exhibits a complex discharge-Manning's n relation, and reliable estimates of the former are dependent upon realistic assignment of the latter. Our study demonstrates that a large recent flood can provide a valuable opportunity to constrain this parameter, and this is illustrated when we model a palaeoflood event in the same reach, and subsequently examine the magnitude-return period consequences of discharge uncertainty within a flood frequency analysis, which contributes its own source of uncertainty.

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

    International Nuclear Information System (INIS)

    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.)

  2. Technical assessment of the bedrock waste storage at the Savannah River Plant

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, R.F.; Corey, J.C.

    1976-11-01

    An assessment of the safety and feasibility of ultimate storage of radioactive wastes produced at the Savannah River Plant (SRP) in horizontal tunnels excavated in the bedrock beneath the plant site is presented. Results indicate that a cavern with an excavated volume of 130 million gallons could contain 80 million gallons of concentrated radioactive SRP wastes with minimal risks if the cavern is located in the impermeable Triassic Basin underlying the Savannah River site. The cavern could be placed so that it would lie wholly within the boundaries of the plantsite. The document summarizes the general geological, hydrological, and chemical knowledge of the geological structures beneath the plantsite; develops evaluation guidelines; and utilizes mathematical models to conduct risk analyses. The risk models are developed from known soil and salt solution mechanics; from past, present, and future geological behavior of the onsite rock formations; and from known waste handling technology. The greatest risk is assessed to exist during transfer of the radioactive wastes to the cavern. When the cavern is filled and sealed, further population risks are asessed to be very low.

  3. Detecting a Defective Casing Seal at the Top of a Bedrock Aquifer.

    Science.gov (United States)

    Richard, Sandra K; Chesnaux, Romain; Rouleau, Alain

    2016-03-01

    An improperly sealed casing can produce a direct hydraulic connection between two or more originally isolated aquifers with important consequences regarding groundwater quantity and quality. A recent study by Richard et al. (2014) investigated a monitoring well installed in a fractured rock aquifer with a defective casing seal at the soil-bedrock interface. A hydraulic short circuit was detected that produced some leakage between the rock and the overlying deposits. A falling-head permeability test performed in this well showed that the usual method of data interpretation is not valid in this particular case due to the presence of a piezometric error. This error is the direct result of the preferential flow originating from the hydraulic short circuit and the subsequent re-equilibration of the piezometric levels of both aquifers in the vicinity of the inlet and the outlet of the defective seal. Numerical simulations of groundwater circulation around the well support the observed impact of the hydraulic short circuit on the results of the falling-head permeability test. These observations demonstrate that a properly designed falling-head permeability test may be useful in the detection of defective casing seals. PMID:26212855

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

    Directory of Open Access Journals (Sweden)

    J. R. Raposo

    2012-02-01

    Full Text Available Quantification of groundwater recharge in crystalline rocks presents great difficulties due to high heterogeneity. Traditionally these rocks have been considered with very low permeability, and their groundwater resources have been usually neglected, although they can have local importance when the bedrock presents a net of fractures well developed. Current European Water Framework Directive requires an efficient management of all groundwater resources, which 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, with a geology mainly dominated by granitic and metasedimentaty rocks, was carried out. A water-balance modeling approach was used for estimating recharge rates in nine pilot catchments representatives of both geologic materials, and results were cross-validated with an independent technique as Chloride mass balance (CMB. A relation among groundwater recharge and total precipitation according to two different logistic curves was found for granites and metasedimentary rocks, which allows the parameterization of recharge by means of few hydrogeological parameters. Total groundwater resources in Galicia-Costa were estimated in 4427 Hm3 yr−1. An analysis of spatial and temporal variability of recharge was also carried out.

  5. 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.

  6. 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.

  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. Toward improved prediction of the bedrock depth underneath hillslopes: Bayesian inference of the bottom-up control hypothesis using high-resolution topographic data

    Science.gov (United States)

    Gomes, Guilherme J. C.; Vrugt, Jasper A.; Vargas, Eurípedes A.

    2016-04-01

    The depth to bedrock controls a myriad of processes by influencing subsurface flow paths, erosion rates, soil moisture, and water uptake by plant roots. As hillslope interiors are very difficult and costly to illuminate and access, the topography of the bedrock surface is largely unknown. This essay is concerned with the prediction of spatial patterns in the depth to bedrock (DTB) using high-resolution topographic data, numerical modeling, and Bayesian analysis. Our DTB model builds on the bottom-up control on fresh-bedrock topography hypothesis of Rempe and Dietrich (2014) and includes a mass movement and bedrock-valley morphology term to extent the usefulness and general applicability of the model. We reconcile the DTB model with field observations using Bayesian analysis with the DREAM algorithm. We investigate explicitly the benefits of using spatially distributed parameter values to account implicitly, and in a relatively simple way, for rock mass heterogeneities that are very difficult, if not impossible, to characterize adequately in the field. We illustrate our method using an artificial data set of bedrock depth observations and then evaluate our DTB model with real-world data collected at the Papagaio river basin in Rio de Janeiro, Brazil. Our results demonstrate that the DTB model predicts accurately the observed bedrock depth data. The posterior mean DTB simulation is shown to be in good agreement with the measured data. The posterior prediction uncertainty of the DTB model can be propagated forward through hydromechanical models to derive probabilistic estimates of factors of safety.

  9. Single-well injection-withdrawal tests (SWIW). Investigation of evaluation aspects under heterogeneous crystalline bedrock conditions

    International Nuclear Information System (INIS)

    Single-well injection-withdrawal (SWIW) tracer tests have been identified by SKB as an investigation method for solute transport properties in the forthcoming site investigations. A previous report presents a literature study as well as scoping calculations for SWIW tests in homogeneous crystalline bedrock environments. The present report comprises further scoping calculations under assumptions of heterogeneous bedrock conditions. Simple but plausible homogeneous evaluation models are tested on simulated SWIW tests in hypothetical heterogeneous two-dimensional fractures. The results from this study indicate that heterogeneity may cause effects of flow irreversibility when background hydraulic gradients are significant and the tested section is located in a dominating flow path. This implies that such conditions make it more difficult to interpret results from SWIW tests of longer duration with sorbing and/or diffusing tracers. Sorption and diffusion processes may be best studied when SWIW tests are conducted in borehole sections with low natural flow rates

  10. Matrix Pore Water in Low Permeable Crystalline Bedrock: An Archive for the Palaeohydrogeological Evolution of the Olkiluoto Investigation Site

    International Nuclear Information System (INIS)

    Matrix pore water in the connected inter- and intragranular pore space of low permeable crystalline bedrock interacts with flowing fracture groundwater predominately by diffusion. Based on the slow exchange between the two water reservoirs, matrix pore water acts as an archive of past changes in fracture groundwater compositions and thus of the palaeohydrological history of a site. Matrix pore water of crystalline bedrock from the olkiluoto investigation site (SW Finland) was characterised using the stable water isotopes (δ18O, δ2H), combined with the concentrations of dissolved chloride and bromide as natural tracers. The comparison of tracer concentrations in pore water and present day fracture groundwater suggest for the pore water the presence of old, dilute meteoric water components that infiltrated into the fractures during various warm climate stages. These different meteoric components can be discerned based on the diffusion distance between the two reservoirs and brought into context with the palaeohydrological evolution of the site. (author)

  11. Chemistry and dissolved gases of matrix pore water and fluid inclusions in Olkiluoto bedrock from drillhole ONK-PH9

    International Nuclear Information System (INIS)

    Matrix pore water and gas dissolved in matrix pore water in drillcore samples from drillhole ONK-PH9 have been successfully characterised for their chemical and isotopic composition. Based on the comparison of natural tracers in matrix pore water and adjacent fracture groundwater, conclusions about the palaeohydrogeological history of the encountered system are drawn. The investigations are based on naturally saturated core samples from the subhorizontal drillhole ONK-PH9 which was drilled from the ONKALO access tunnel at a vertical depth of 306 m into the bedrock intersecting the water-conducting hydrogeological zone HZ20B. Pore water samples were taken from this highly transmissive water-conducting zone and the adjacent low transmissive bedrock along a continuous eleven metre long profile. Additional samples have been collected at intervals between five and ten metres until 100 m drillhole length (DHL)

  12. The bedrock topography of Starbuck Glacier, Antarctic Peninsula, as determined by radio-echo soundings and flow modeling

    OpenAIRE

    Farinotti, Daniel; King, Edward C.; AlbrechtL, Anika; Huss, Matthias; Gudmundsson, G. Hilmar

    2014-01-01

    A glacier-wide ice-thickness distribution and bedrock topography is presented for Starbuck Glacier, Antarctic Peninsula. The results are based on 90 km of ground-based radio-echo sounding lines collected during the 2012/13 field season. Cross-validation with ice-thickness measurements provided by NASA's IceBridge project reveals excellent agreement. Glacier-wide estimates are derived using a model that calculates distributed ice thickness, calibrated with the radio-echo soundings. Additional ...

  13. Pseudo 3-D P wave refraction seismic monitoring of permafrost in steep unstable bedrock

    Science.gov (United States)

    Krautblatter, Michael; Draebing, Daniel

    2014-02-01

    permafrost in steep rock walls can cause hazardous rock creep and rock slope failure. Spatial and temporal patterns of permafrost degradation that operate at the scale of instability are complex and poorly understood. For the first time, we used P wave seismic refraction tomography (SRT) to monitor the degradation of permafrost in steep rock walls. A 2.5-D survey with five 80 m long parallel transects was installed across an unstable steep NE-SW facing crestline in the Matter Valley, Switzerland. P wave velocity was calibrated in the laboratory for water-saturated low-porosity paragneiss samples between 20°C and -5°C and increases significantly along and perpendicular to the cleavage by 0.55-0.66 km/s (10-13%) and 2.4-2.7 km/s (>100%), respectively, when freezing. Seismic refraction is, thus, technically feasible to detect permafrost in low-porosity rocks that constitute steep rock walls. Ray densities up to 100 and more delimit the boundary between unfrozen and frozen bedrock and facilitate accurate active layer positioning. SRT shows monthly (August and September 2006) and annual active layer dynamics (August 2006 and 2007) and reveals a contiguous permafrost body below the NE face with annual changes of active layer depth from 2 to 10 m. Large ice-filled fractures, lateral onfreezing of glacierets, and a persistent snow cornice cause previously unreported permafrost patterns close to the surface and along the crestline which correspond to active seasonal rock displacements up to several mm/a. SRT provides a geometrically highly resolved subsurface monitoring of active layer dynamics in steep permafrost rocks at the scale of instability.

  14. Sample collection, treatment and measurements of soil, bedrock and building materials

    International Nuclear Information System (INIS)

    The environmental radionuclides can be divided into three groups according to origin (a) Primordial origin, (b) Continuously produced by natural processes other than the decay of primordial radionuclides and (c) Those generated by man's activities. The natural radionuclides of the first group are of interest for indoor exposure and related to ''U-238'', ''Th-232'' series plus K-40 respectively, present in soil, bedrock and building materials. An extensive literature exists on the U and Th concentrations in rocks. Most of the data refer to the radon decay products with NaI detectors assuming a perfect equilibrium all along the U and Th. However, an equilibrium down to the Ra-226 or Ra-228 may exist in igneous rocks and old sediments. But in recent sediments and soils an equilibrium is hardly found. There is also the problem of the radon escape from the sample due to the inert nature of the radon and the large concentration gradient. Even a small crack or gap in the sample container may lead to an important radon loss. The concentrations of natural radionuclides may be measured by using a co-axial germanium detector for the determination of the high energy gamma-rays emitted by Ra-226, Ra-228, and K-40. For lower energy gamma-rays i.e. in the range from tens to hundreds of Kev (of interest for the measurement of 185.7 Kev from U-235 and 63.3 plus 92.6 Kev from Th-234) an x-gamma co-axial detector is needed. For a better resolution in the lowest energy range a Ge(HP) planar detector would be more appropriate. 10 refs, 4 figs

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

    International Nuclear Information System (INIS)

    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 Kd. 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

  16. 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

  17. Geology, Bedrock, Farner Quad line work. Incomplete lines., Published in 2006, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2006. It is described as...

  18. Geology, Bedrock, Topton Quad line work. Incomplete lines., Published in 2006, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2006. It is described as...

  19. Geology, Bedrock, Wisconsin Geologic and Natural History Survey has these maps, Published in 2006, 1:24000 (1in=2000ft) scale, Lafayette County Land Records.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2006. It is described as...

  20. Digital Polygon Model Grid of the Hydrogeologic Framework of Bedrock Units for a Simulation of Groundwater Flow for the Lake Michigan Basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — 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...

  1. Geology, Bedrock, Zionville Quad line work. Incomplete lines., Published in 2006, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2006. It is described as...

  2. Geology, Bedrock, Geologic Map of the Henderson Quadrangle, Published in 2004, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Field Observation information as of 2004. It is described...

  3. Study-area boundary for "Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado." Hydrologic Atlas 742

    Science.gov (United States)

    Rafferty, Sharon

    1998-01-01

    This digital geospatial data set consists of outlines of the study area in the report "Structure, Outcrop, and Subcrop of the Bedrock Aquifers Along the Western Margin of the Denver Basin, Colorado" (Robson and others, 1998).

  4. 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)

    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, Kd, and surface distribution ratios, Ka; 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.)

  5. Geology, Bedrock, Huntdale Quad line work. Incomplete lines., Published in 2006, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2006. It is described as...

  6. Groundwater flow paths in the bedrock fracture zones revealed by using the stable isotopes of oxygen and hydrogen in the Talvivaara mine gypsum pond area, Northeastern Finland

    OpenAIRE

    KittilÀ, Anniina

    2015-01-01

    Bedrock fracturing is considerably extensive and distinct in Finland, and the fractures that are open, conductive and interconnected usually control the groundwater flow paths in fractured bedrock. This highlights the importance of knowing the locations and hydraulic connections of water conducting fracture zones particularly in mining areas, because they can transport adverse substances outside the mining area. In this study, it is focused on examining possible hydraulic connections of bedro...

  7. Effect of bedrock permeability on subsurface stormflow and the water balance of a trenched hillslope at the Panola Mountain Research Watershed, Georgia, USA

    Science.gov (United States)

    Tromp-van, Meerveld, H. J.; Peters, N.E.; McDonnell, Jeffery J.

    2007-01-01

    The effect of bedrock permeability on subsurface stormflow initiation and the hillslope water balance is poorly understood. Previous hillslope hydrological studies at the Panola Mountain Research Watershed (PMRW), Georgia, USA, have assumed that the bedrock underlying the trenched hillslope is effectively impermeable. This paper presents a series of sprinkling experiments where we test the bedrock impermeability hypothesis at the PMRW. Specifically, we quantify the bedrock permeability effects on hillslope subsurface stormflow generation and the hillslope water balance at the PMRW. Five sprinkling experiments were performed by applying 882-1676 mm of rainfall over a ???5.5 m ?? 12 m area on the lower hillslope during ???8 days. In addition to water input and output captured at the trench, we measured transpiration in 14 trees on the slope to close the water balance. Of the 193 mm day-1 applied during the later part of the sprinkling experiments when soil moisture changes were small, 175 mm day-1 (91%). Bedrock moisture was measured at three locations downslope of the water collection system in the trench. Bedrock moisture responded quickly to precipitation in early spring. Peak tracer breakthrough in response to natural precipitation in the bedrock downslope from the trench was delayed only 2 days relative to peak tracer arrival in subsurface stormflow at the trench. Leakage to bedrock influences subsurface stormflow at the storm time-scale and also the water balance of the hillslope. This has important implications for the age and geochemistry of the water and thus how one models this hillslope and watershed. Copyright ?? 2006 John Wiley & Sons, Ltd.

  8. 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)

    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

  9. The relationship between hydrogeologic properties and sedimentary facies: an example from Pennsylvanian bedrock aquifers, southwestern Indiana

    International Nuclear Information System (INIS)

    The relationship between the hydrogeologic properties and sedimentary facies of shallow Pennsylvanian bedrock aquifers was examined using detailed sedimentologic descriptions, aquifer (slug) tests, and gamma ray logs. The main goal of the study was to determine if it was possible to reliably estimate near-well hydraulic conductivities using core descriptions and logging data at a complex field site, based on assignment of consistent conductivity indicators to individual facies. Lithologic information was gathered from three sources: core descriptions, simplified lithologic columns derived from the core descriptions, and drillers' logs. Gamma ray data were collected with a conventional logging instrument. Slug tests were conducted in all wells containing screened zones entirely within the Pennsylvanian facies of interest. Simplified subsets of sedimentologic facies were assembled for classification of subsurface geology, and all rocks within the screened intervals of test wells were assigned to individual facies based on visual descriptions. Slug tests were conducted to determine the bulk hydraulic conductivity (a spatial average within the screened interval) in the immediate vicinity of the wells, with measured values varying from 10-4 m/s to 10-8 m/s. Gamma ray logs from these wells revealed variations in raw counts above about 1.5 orders of magnitude. Data were combined using simple linear and nonlinear inverse techniques to derive relations between sedimentologic facies, gamma ray signals, and bulk hydraulic conductivities. The analyses suggest that facies data alone, even those derived from detailed core descriptions, are insufficient for estimating hydraulic conductivity in this setting to better than an order of magnitude. The addition of gamma ray data improved the estimates, as did selective filtering of several extreme values from the full data set. Better estimates might be obtained through more careful field measurements and reduction of associated

  10. What about the regolith, the saprolite and the bedrock? Proposals for classifying the subsolum in WRB

    Science.gov (United States)

    Juilleret, Jérôme; Dondeyne, Stefaan; Hissler, Christophe

    2014-05-01

    Since soil surveys in the past were mainly conducted in support of agriculture, soil classification tended to focus on the solum representing mainly the upper part of the soil cover that is exploited by crops; the subsolum was largely neglected. When dealing with environmental issues - such as vegetation ecology, groundwater recharge, water quality or waste disposal - an integrated knowledge of the solum to subsolum continuum is required. In the World Reference Base for soil resources (WRB), the lower boundary for soil classification is set at 2 m, including both loose parent material as well as weathered and continuous rock. With the raised concern for environmental issues and global warming, classification concepts in WRB have been widened over the last decades. Cryosols were included as a separate Reference Soil Group to account for soils affected by perennial frost; Technosols were included to account for soils dominated by technical human activity. Terms for describing and classifying the subsolum are however still lacking. Nevertheless, during soil surveys a wealth of information on the subsolum is also collected. In Luxembourg, detailed soil surveys are conducted according to a national legend which is correlated to WRB. Quantitative data on characteristics of the subsolum, such as bedding, cleavage, fractures density and dipping of the layer, are recorded for their importance in relation to subsurface hydrology. Drawing from this experience, we propose defining four "subsolum materials" and which could be integrated into WRB as qualifiers. Regolitic materials are composed of soil and rock fragments deposited by water, solifluction, ice or wind; Paralithic materials consist of partly weathered rock with geogenic structural features; Saprolitic materials are formed from in situ weathering of the underlying geological deposits; Lithic materials correspond to unaltered bedrock. We discuss how these characteristics could be integrated into WRB and how additional

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

    Science.gov (United States)

    Wieczorek, Michael E.; 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

  12. The effect of vegetation on infiltration in shallow soils underlain by fissured bedrock

    Science.gov (United States)

    Stothoff, S. A.; Or, D.; Groeneveld, D. P.; Jones, S. B.

    1999-05-01

    Mean annual infiltration above the high-level waste repository proposed to be sited at Yucca Mountain, Nevada, has a large impact on assessments of repository performance. Ongoing investigations of infiltration processes have identified the relatively horizontal caprock environment above portions of the repository as a potentially large source of infiltrating waters, due to shallow, permeable soils above a moderately welded tuff with large soil-filled fissures. The combination of shallow soils and fissured bedrock allows rapid penetration of wetting pulses to below the rooting zone. Plant uptake can strongly reduce net infiltration in arid environments with high water storage capacity, and, despite the low water storage capacity, there is a relatively high vegetation density in this environment. The apparent discrepancy between high vegetation density and low water storage motivates the study of plant-hydrologic interactions in this semiarid environment. Field observations were coupled with plant- and landscape-scale models to provide insight into plant-hydrologic interactions. Several lines of evidence, including: (i) linear plant growth features observed on aerial photographs; (ii) comparisons of plant cover within the fissured environment and comparable environments lacking fissures; and (iii) direct excavations, all suggest that the widely spaced soil-filled fissures are conducive to plant growth even when fissures are buried at soil depths exceeding 30 cm. Results from a mechanistic simulation model for root growth into fissures suggest that the additional (sheltered) plant-available soil water within fissures provides a competitive advantage for plant establishment. Therefore, plants that germinate above a fissure are more likely to survive, in turn developing linear features above fissures. Having established that plants preferentially root within soil-filled fissures in the caprock environment, a set of simulations were performed to examine the hydrologic

  13. Single-well injection-withdrawal tests (SWIW). Literature review and scoping calculations for homogeneous crystalline bedrock conditions

    International Nuclear Information System (INIS)

    This report describes a literature review and scoping calculations carried out in order to test the feasibility of using SWIW (Single Well Injection Withdrawal) tracer experiments for expected hydraulic conditions in Swedish bedrock. The motivation for using SWIW tests in the site investigation programme is that extensive cross-hole tracer tests may not be possible and that such SWIW tests are more or less the only available single-hole tracer test method. The scoping calculations are aimed at establishing conditions under which SWIW tests should be feasible, by studying experimental attributes such as expected bedrock properties (transmissivity, porosity, etc), ambient hydraulic gradients, duration of various experimental phases, hydraulic injection pressure and parameter identification possibilities. Particular emphasis has been placed on the use of the dilution probe as an experimental device for SWIW, although the scoping results also should be considered applicable to any experimental equipment approach. The results from the scoping calculations indicate that SWIW tests using the dilution probe are feasible under the required experimental and site requirements for the forthcoming site investigations programme. The characteristic flow reversibility feature inherent in SWIW tests causes some differences compared with cross-hole tracer tests. Advective parameters (i.e. mobile porosity, dispersivity) are generally more difficult to identify/estimate and the same may also be said about equilibrium sorption. Time-dependent processes, on the other hand, generally benefit from the flow reversibility, in principle even in the presence of heterogeneity. However, it may not always be possible to identify time-dependent processes, such as matrix diffusion, for expected conditions in Swedish bedrock. Experimental aims may be allowed to vary depending on the specific conditions (transmissivity, hydraulic gradient, etc.) in the tested borehole section

  14. 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; Armstrong, 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. PMID:11554245

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

    Energy Technology Data Exchange (ETDEWEB)

    Lipping, T. (Tampere Univ. of Technology, Pori (Finland)); Ikonen, A.T.K. (eds.)

    2011-01-15

    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.)

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

    International Nuclear Information System (INIS)

    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.)

  17. Burial and exhumation of temperate bedrock reefs as elucidated by repetitive high-resolution sea floor sonar surveys: Spatial patterns and impacts to species' richness and diversity

    Science.gov (United States)

    Storlazzi, Curt D.; Fregoso, Theresa A.; Figurski, Jared D.; Freiwald, Jan; Lonhart, Steve I.; Finlayson, David P.

    2013-03-01

    To understand how chronic sediment burial and scour contribute to variation in the structure of algal and invertebrate communities on temperate bedrock reefs, the dynamics of the substrate and communities were monitored at locations that experience sand inundation and adjacent areas that do not. Co-located benthic scuba-transect surveys and high-resolution swath-sonar surveys were completed on bedrock reefs on the inner shelf of northern Monterey Bay, CA, in early winter 2009, spring 2010, and summer 2010. Analysis of the sonar surveys demonstrates that during the 8 months over which the surveys were conducted, 19.6% of the study area was buried by sand while erosion resulted in the exposure of bedrock over 13.8% of the study area; the remainder underwent no change between the surveys. Substrate classifications from the benthic transect surveys correlated with classifications generated from the sonar surveys, demonstrating the capacity of high-resolution sonar surveys to detect burial of bedrock reefs by sediment. On bedrock habitat that underwent burial and exhumation, species' diversity and richness of rock-associated sessile and mobile organisms were 50-66% lower as compared to adjacent stable bedrock habitat. While intermediate levels of disturbance can increase the diversity and richness of communities, these findings demonstrate that burial and exhumation of bedrock habitat are sources of severe disturbance. We suggest that substrate dynamics must be considered when developing predictions of benthic community distributions based on sea floor imagery. These results highlight the need for predictive models of substrate dynamics and for a better understanding of how burial and exhumation shape benthic communities.

  18. Bedrock structures controlling the spatial occurrence and geometry of 1.8 Ga younger glacifluvial deposits - Example from First Salpausselkä, southern Finland

    Science.gov (United States)

    Skyttä, Pietari; Kinnunen, Jussi; Palmu, Jukka-Pekka; Korkka-Niemi, Kirsti

    2015-12-01

    The glacifluvial deposits within formerly glaciated areas of southern Finland comprise the predominance of well-sorted subglacial and ice marginal sediments. The deposits are less than 100 m thick and form significant aquifers utilized by the respective areas. The spatial correlation of subglacial deposits with bedrock structures, particularly the deformation zones, has been long recognized, but most often not systematically investigated. The purpose of this study was to understand how specific bedrock structures control the position and processes of formation of glacifluvial deposits, using the First Salpausselkä area of southern Finland as a model area. We apply a means of structural analysis to compile structural interpretations (form lines and 3D-surfaces) of the bedrock and correlate the results with the patterns of the glacifluvial deposits and the topography of the underlying bedrock surface. Two major E-W striking shear zones defining abrupt breaks at the bedrock surface along with secondary SW-NE striking splays, originating from the horsetail-like termination of the Somero shear zone, control the deposition of eskers and ice marginal deposits. Based on correlations between the bedrock topography, glacial erosion and sedimentation, we infer that laterally extensive shear zones may have indirectly affected the glacial dynamics within the areas of areal scour more than previously considered. Recognized deformation zones are important for modelling the internal stratigraphy of glacifluvial deposits, their hydrogeological properties and for mapping fresh water supplies within the Nordic countries and other glaciated areas which have undergone substantial tectonic deformation. The development of 3D geologic models is essential for understanding regional-scale correlations between Quaternary sediments and bedrock structures.

  19. Geochemistry of highly acidic mine water following disposal into a natural lake with carbonate bedrock

    International Nuclear Information System (INIS)

    plant roots at low pH (up to 3326 mg/kg As), (ii) adsorption at increasing pH near the gypsum/calcite boundary (up to 1812 mg/kg Pb, 2531 mg/kg Cu, and 36 mg/kg Cd), and (iii) precipitation of carbonates (up to 5177 mg/kg Zn and 810 mg/kg Mn; all data corrected to a wet base). The infiltration rate was approximately equal to the discharge rate, thus gypsum and hydroxide precipitation had not resulted in complete clogging of the lake bedrocks.

  20. Field measurements of incision rates following bedrock exposure: Implications for process controls on the long profiles of valleys cut by rivers and debris flows

    Science.gov (United States)

    Stock, Jonathan D.; Montgomery, David R.; Collins, Brian D.; Dietrich, William E.; Sklar, Leonard

    2005-01-01

    Until recently, published rates of incision of bedrock valleys came from indirect dating of incised surfaces. A small but growing literature based on direct measurement reports short-term bedrock lowering at geologically unsustainable rates. We report observations of bedrock lowering from erosion pins monitored over 1–7 yr in 10 valleys that cut indurated volcanic and sedimentary rocks in Washington, Oregon, California, and Taiwan. Most of these channels have historically been stripped of sediment. Their bedrock is exposed to bed-load abrasion, plucking, and seasonal wetting and drying that comminutes hard, intact rock into plates or equant fragments that are removed by higher flows. Consequent incision rates are proportional to the square of rock tensile strength, in agreement with experimental results of others. Measured rates up to centimeters per year far exceed regional long-term erosion-rate estimates, even for apparently minor sediment-transport rates. Cultural artifacts on adjoining strath terraces in Washington and Taiwan indicate at least several decades of lowering at these extreme rates. Lacking sediment cover, lithologies at these sites lower at rates that far exceed long-term rock-uplift rates. This rate disparity makes it unlikely that the long profiles of these rivers are directly adjusted to either bedrock hardness or rock-uplift rate in the manner predicted by the stream power law, despite the observation that their profiles are well fit by power-law plots of drainage area vs. slope. We hypothesize that the threshold of motion of a thin sediment mantle, rather than bedrock hardness or rock-uplift rate, controls channel slope in weak bedrock lithologies with tensile strengths below ∼3–5 MPa. To illustrate this hypothesis and to provide an alternative interpretation for power-law plots of area vs. slope, we combine Shields' threshold transport concept with measured hydraulic relationships and downstream fining rates. In contrast to fluvial

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

    International Nuclear Information System (INIS)

    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.)

  2. Final disposal of spent nuclear fuel in the Finnish bedrock. Preliminary site investigations; Kaeytetyn polttoaineen loppusijoitus Suomen kallioperaeaen; Alustavat sijoituspaikkatutkimukset

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Field evidence of hydraulic connections between bedrock aquifers and overlying granular aquifers: examples from the Grenville Province of the Canadian Shield

    Science.gov (United States)

    Richard, Sandra K.; Chesnaux, Romain; Rouleau, Alain; Morin, Roger; Walter, Julien; Rafini, Silvain

    2014-12-01

    Field evidence of hydraulic connections between a bedrock aquifer and an overlying granular aquifer in the Canadian Shield (Grenville Province) is presented. This issue is rarely considered and investigated despite its important hydraulic and chemical consequences and its widespread occurrence worldwide. The methodology employed is based on complementary field tests conducted at specific experimental sites instrumented both in the rock and in the overlying deposits. One of the bedrock sites revealed a natural hydraulic connection with the overlying granular aquifer caused by the weathered surface of the uppermost bedrock. Another site revealed an artificial hydraulic connection between the bedrock and the granular aquifer created by an improperly sealed casing. A regional study showed that hydraulic connections yield an erroneous interpretation of the true hydraulic properties of the tested aquifer. The detection of hydraulic connections is therefore essential to properly define well-capture areas and contamination conditions. It is recommended to practitioners that pumping tests be performed as well as hydrochemical comparisons of each existing aquifer unit. Falling-head permeability tests are also helpful in verifying the quality of the seal at the bedrock-casing contact. More effective procedural controls and better well-construction practices are necessary to reduce the risks of cross-contamination induced by defective seals.

  4. Hydrogeologic Characterization of Fractured Crystalline Bedrock on the Southern Part of Manhattan, New York, Using Advanced Borehole Geophysical Methods

    Science.gov (United States)

    Stumm, F.; Chu, A.; Joesten, P. K.; Lane, J. W.

    2007-12-01

    ABSTRACT. Advanced borehole-geophysical methods were used to assess the hydrogeology of fractured crystalline bedrock in 31 of 64 boreholes on the southern part of Manhattan Island, N.Y. The majority of boreholes penetrated gneiss, schist, and other crystalline bedrock, and had an average depth of 591 ft (180 m) below land surface (BLS). In this study we use a combination of advanced and conventional borehole geophysical logs, and hydraulic measurements to characterize the fractured-rock ground-water flow system in southern Manhattan, N.Y. Borehole-geophysical logs collected in this study included natural gamma, single-point-resistance (SPR), short-normal resistivity (R), mechanical and acoustic caliper, magnetic susceptibility, borehole-fluid temperature and resistivity, specific conductance (SpC), dissolved oxygen (DO), pH, redox, heat-pulse flowmeter (at eight selected boreholes), borehole deviation, acoustic and optical televiewer (ATV and OTV), and directional borehole radar (at 23 selected boreholes). A new geophysical probe that collects multiple fluid parameters, included fluid- temperature, SpC, DO, pH, and redox logs; these were used to help delineate transmissive fractures in the boreholes. All boreholes penetrated moderately fractured bedrock that contained medium and large fractures. A total of 208 large fractures were delineated in the 31 boreholes logged with the OTV. Stereonet analysis of the large fractures indicates most are part of a subhorizontal population cluster with a mean orientation of N43 degrees E, 07 degrees SE and a smaller secondary population cluster dipping toward the northwest. A total of 53 faults were delineated with two major population clusters--one with a mean orientation of N12 degrees W, 66 degrees W and the other with a mean orientation of N11 degrees W, 70 degrees E. Foliation was fairly consistent throughout the study area with dip azimuths ranging from northwest to southwest and dip angles ranging from 30 to 70 degrees

  5. Geology, Bedrock, Data contains 10 foot elevation contours (1 foot in some areas) showing the approximate bedrock surface elevation within McLain State Park, Houghton, County, Michigan. Contours were generated with the Surfer 12 software package using soil test borings and, Published in 2014, Not Applicable scale, Michigan Coastal Zone Management Program.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at Not Applicable scale, was produced all or in part from Field Survey/GPS information as of 2014. The source is Michigan...

  6. Geology, Bedrock, Bedrock geologic map of the NPS Blue Ridge Parkway corridor. Majority of central and southern segments completed with entire project completed by October 2008., Published in 2004, 1:12000 (1in=1000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:12000 (1in=1000ft) scale, was produced all or in part from Field Survey/GPS information as of 2004. It is described as...

  7. Geology, Bedrock, Drill hole locations, most with samples, for oil and gas exploratory wells, municipal water wells, stratigraphic test holes, and mineral exploration holes. Note that bedrock samples may not be available for all drill holes., Published in 1998, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 1998. It is described as...

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

    International Nuclear Information System (INIS)

    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

  9. 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

  10. Determination of Bedrock Variations and S-wave Velocity Structure in the NW part of Turkey for Earthquake Hazard Mitigation

    Science.gov (United States)

    Ozel, A. O.; Arslan, M. S.; Aksahin, B. B.; Genc, T.; Isseven, T.; Tuncer, M. K.

    2015-12-01

    Tekirdag region (NW Turkey) is quite close to the North Anatolian Fault which is capable of producing a large earthquake. Therefore, earthquake hazard mitigation studies are important for the urban areas close to the major faults. From this point of view, integration of different geophysical methods has important role for the study of seismic hazard problems including seismotectonic zoning. On the other hand, geological mapping and determining the subsurface structure, which is a key to assist management of new developed areas, conversion of current urban areas or assessment of urban geological hazards can be performed by integrated geophysical methods. This study has been performed in the frame of a national project, which is a complimentary project of the cooperative project between Turkey and Japan (JICA&JST), named as "Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education". With this principal aim, this study is focused on Tekirdag and its surrounding region (NW of Turkey) where some uncertainties in subsurface knowledge (maps of bedrock depth, thickness of quaternary sediments, basin geometry and seismic velocity structure,) need to be resolved. Several geophysical methods (microgravity, magnetic and single station and array microtremor measurements) are applied and the results are evaluated to characterize lithological changes in the region. Array microtremor measurements with several radiuses are taken in 30 locations and 1D-velocity structures of S-waves are determined by the inversion of phase velocities of surface waves, and the results of 1D structures are verified by theoretical Rayleigh wave modelling. Following the array measurements, single-station microtremor measurements are implemented at 75 locations to determine the predominant frequency distribution. The predominant frequencies in the region range from 0.5 Hz to 8 Hz in study area. On the other hand, microgravity and magnetic measurements are performed on

  11. High resolution mapping of offshore and onshore glaciogenic features in metamorphic bedrock terrain, Melville Bay, northwestern Greenland

    Science.gov (United States)

    Freire, Francis; Gyllencreutz, Richard; Greenwood, Sarah L.; Mayer, Larry; Egilsson, Arnar; Thorsteinsson, Tómas; Jakobsson, Martin

    2015-12-01

    Geomorphological studies of previously glaciated landscapes are important to understand how ice sheets and glaciers respond to rapidly changing climate. Melville Bay, in northwestern Greenland, contains some of the most sensitive but least studied ice sheet sectors in the northern hemisphere, where the bathymetric knowledge previously was restricted to a few sparsely distributed single beam echo soundings. We present here the results of high-resolution, geomorphological mapping of the offshore and onshore landscapes in Melville Bay using multibeam sonar and satellite data, at 5- and 10-m resolutions respectively. The results show a similar areally-scoured bedrock-dominated landscape with a glacially modified cnoc-and-lochan morphology on the inner shelf (150-500 m depth) and on the nearby exposed coast. This is manifested by the presence of U-shaped troughs, moutonée-type elongated landforms, stoss-and-lee forms, and streamlined features. The submarine landscape shows features that are characteristic of bedrock in folded, faulted, and weathered metamorphic terrain, and, to a lesser extent, glacially molded bedforms; while coastal landforms exhibit higher relief, irregular-shaped basins, and more subdued fracture valleys. Although generally similar, the onshore and offshore landscapes contain examples of distinctly different landform patterns, which are interpreted to reflect a longer exposure to long-term deep weathering as well as to more recent periglacial weathering processes on land. The spatial variability in the distribution of landforms across the landscape in both study areas is mostly attributed to differences in lithological properties of the bedrock. The lack of sediment cover on the inner shelf is likely a result of a capacity for sediment erosion and removal by the West Greenland Current flowing northward over the area in combination with limited sediment supply from long sea ice-cover seasons. The distribution and orientation of the landforms in the

  12. Establishing time-dependent model of deformation modulus caused by bedrock excavation rebound by inverse analysis method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Rock rebound relaxation deformation,or even rock burst,caused by the excavation of dam base and abutment or high rock slope affects their stability and results in the fall of mechanical properties of the rock.So an inverse analysis method was proposed in this paper to establish the time-dependent model of deformation modulus caused by excavation rebound.The basic principle is based on the combination of observed data of the excavation rebound deformation of dam abutment or rock slope,and the calculated rebound deformation by FEM under ground stress at the corresponding time in the excavation process.The norm of the residuals of observed data and calculated data are taken as the objective function.Accordingly,the time-dependent model of bedrock deformation modulus can be established.The method displays its significance in the design of excavation,construction and operation management of dam base and high slope.

  13. Differentiation of fen bedrock in the Ełk Lakeland (NE Poland in relation to late Pleistocene terrain morphogenesis

    Directory of Open Access Journals (Sweden)

    Lemkowska Bożena

    2015-12-01

    Full Text Available The Ełk Lakeland (NE Poland with the area of 263 100 ha was formed during Vistulian glaciation. More than 66% of this region was shaped during the Leszno phase, 15% during the Poznań phase, and 19% during the Pomeranian phase. There are 1854 fens which cover the area of 7.3 % of the Ełk Lakeland mesoregion. Fens have an area of 10.3 ha on average. About 82.5% of the studied fens is located on gyttja deposits, which suggests post-lacustrine origin of the wetlands. Primary the lakes had covered 11% of the Ełk Lakeland, and 6.3% was transformed into fens. Most of them (60% was formed on organic gyttja, 16% on calcareous gyttja, and 6% on clay gyttja. About 17.5% of fens was formed as a result of paludification. The types of bedrock underlying peats differ depending on the phases of glaciation.

  14. Central radon data base and digitized bedrock map of US EPA (Environmental Protection Agency) Region 1. Technical report

    International Nuclear Information System (INIS)

    This research entails compilation, management, and evaluation of existing data on domestic radon levels. The work requires the cooperation of radon programs throughout Region 1 states. The updated data base has geographic capabilities and can be used to gain a clearer picture of areas with high radon levels. The research for the report includes updating the radon data base for EPA's Region 1 and digitizing the existing Bedrock Geologic Map. Lifetime exposure to high indoor radon gas levels contributes to an increased risk of lung cancer. Geologic parameters are thought to be predictive factors of both well water and indoor radon levels. Therefore, because radon is an important environmental risk and because risk communication is likely to play a central role in EPA's policies for radon related risk, the project attempts to develop appropriate radon risk communication strategies

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

    Directory of Open Access Journals (Sweden)

    M. Bomberg

    2015-08-01

    Full Text Available 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.

  16. 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.

  17. 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

  18. Geomorphology of the Alluvial Sediments and Bedrock in an Intermontane Basin: Application of Variogram Modeling to Electrical Resistivity Soundings

    Science.gov (United States)

    Khan, Adnan Ahmad; Farid, Asam; Akhter, Gulraiz; Munir, Khyzer; Small, James; Ahmad, Zulfiqar

    2016-05-01

    The study describes a methodology used to integrate legacy resistivity data with limited geological data in order to build three-dimensional models of the near subsurface. Variogram analysis and inversion techniques more typically found in the petroleum industry are applied to a set of 1D resistivity data taken from electrical surveys conducted in the 1980s. Through careful integration with limited geological data collected from boreholes and outcrops, the resultant model can be visualized in three dimensions to depict alluvium layers as lithological and structural units within the bedrock. By tuning the variogram parameters to account for directionality, it is possible to visualize the individual lithofacies and geomorphological features in the subsurface. In this study, an electrical resistivity data set collected as part of a groundwater study in an area of the Peshawar basin in Pakistan has been re-examined. Additional lithological logs from boreholes throughout the area have been combined with local outcrop information to calibrate the data. Tectonic activity during the Himalayan orogeny has caused uplift in the area and generated significant faulting in the bedrock resulting in the formation of depressions which are identified by low resistivity values representing clays. Paleo-streams have reworked these clays which have been eroded and replaced by gravel-sand facies along paleo-channels. It is concluded that the sediments have been deposited as prograding fan-shaped bodies and lacustrine deposits with interlayered gravel-sand and clay-silt facies. The Naranji area aquifer system has thus been formed as a result of local tectonic activity with fluvial erosion and deposition and is characterized by coarse sediments with high electrical resistivities.

  19. Multi-isotope (carbon and chlorine) analysis for fingerprinting and site characterization at a fractured bedrock aquifer contaminated by chlorinated ethenes

    DEFF Research Database (Denmark)

    Palau, Jordi; Marchesi, Massimo; Chambon, Julie Claire Claudia;

    2014-01-01

    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...

  20. Long term changes in millipede assemblages (Diplopoda) in alpine habitats on granite and llimestone bedrocks in the West Tatra Mts., Slovakia

    Czech Academy of Sciences Publication Activity Database

    Tajovský, Karel

    Olomouc : Institute of Soil Biology , BC ASCR, 2014. s. 92. ISBN 978-80-86525-28-0. [International Congress of Myriapodology /16./. 20.07.2014-25.07.2014, Olomouc] Institutional support: RVO:60077344 Keywords : long term changes * millipede assemblages * alpine habitats * granite and llimestone bedrocks Subject RIV: EH - Ecology, Behaviour

  1. Location of wells shown in "Structure, outcrop,, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado." Hydrologic Atlas 742

    Science.gov (United States)

    Rafferty, Sharon

    1998-01-01

    This digital geospatial data set consists of locations of coal, oil, gas and water wells shown as data points in the report, "Structure, Outcrop, and Subcrop of the Bedrock Aquifers Along the Western Margin of the Denver Basin, Colorado" (Robson and others, 1998).

  2. Characteristics of the thermal regime in steep bedrock permafrost in the European Alps described by borehole temperatures and heat conduction modeling

    Science.gov (United States)

    Noetzli, J.; Deline, P.; Phillips, M.; von Poschinger, A.

    2012-04-01

    Permafrost in the Alps occurs within three main landforms - rock glaciers, debris slopes and steep bedrock. In contrast to rock glaciers and debris slopes, permafrost in steep bedrock reacts directly, fast and sensitively to changes in atmospheric conditions and these areas are therefore important for monitoring purposes. In addition, the observation of the state and changes of permafrost in steep bedrock is relevant for the stability and maintenance of infrastructure as well as the assessment and possible change of slope stability in high mountain areas. Mainly due to the difficulties of access, however, mountain permafrost monitoring activities in the Alps have concentrated on rock glaciers and debris slopes in their beginning more than 20 years ago and only started to focus on bedrock permafrost in the past decade. During the past about 5 years a number of new boreholes with depths ranging from 10 to 60 m have been installed in the scope of different research and monitoring projects at high Alpine sites in Switzerland (e.g., Schilthorn, Matterhorn, Gemsstock), Germany (e.g., Zugspitze), and France (e.g., Aiguille du Midi). Several of the boreholes have been drilled across a crest or perpendicular to the surface. In this contribution, we compare the data and discuss the main results gained from the different borehole sites in steep bedrock. Because of the limited observation period, the extreme spatial variability in these areas, and the invisibility of the phenomenon, we combine the point measurements with numerical heat conduction modeling for extrapolation in time and space to allow a more comprehensive interpretation. In addition to the basic characteristics that the temperature regime in bedrock is mainly controlled by conduction and no thick surface cover (such as snow, debris, blocks) or latent heat effects (low ice contents) mask the changes in atmospheric conditions, a number of specifics of permafrost temperatures in steep bedrock can be observed: a

  3. Impacts of forest harvesting on mobilization of Hg and MeHg in drained peatland forests on black schist or felsic bedrock.

    Science.gov (United States)

    Ukonmaanaho, Liisa; Starr, Mike; Kantola, Marjatta; Laurén, Ari; Piispanen, Juha; Pietilä, Heidi; Perämäki, Paavo; Merilä, Päivi; Fritze, Hannu; Tuomivirta, Tero; Heikkinen, Juha; Mäkinen, Jari; Nieminen, Tiina M

    2016-04-01

    Forest harvesting, especially when intensified harvesting method as whole-tree harvesting with stump lifting (WTHs) are used, may increase mercury (Hg) and methylmercury (MeHg) leaching to recipient water courses. The effect can be enhanced if the underlying bedrock and overburden soil contain Hg. The impact of stem-only harvesting (SOH) and WTHs on the concentrations of Hg and MeHg as well as several other variables in the ditch water was studied using a paired catchment approach in eight drained peatland-dominated catchments in Finland (2008-2012). Four of the catchments were on felsic bedrock and four on black schist bedrock containing heavy metals. Although both Hg and MeHg concentrations increased after harvesting in all treated sites according to the randomized intervention analyses (RIAs), there was only a weak indication of a harvest-induced mobilization of Hg and MeHg into the ditches. Furthermore, no clear differences between WTHs and SOH were found, although MeHg showed a nearly significant difference (p = 0.06) between the harvesting regimes. However, there was a clear bedrock effect, since the MeHg concentrations in the ditch water were higher at catchments on black schist than at those on felsic bedrock. The pH, suspended solid matter (SSM), dissolved organic carbon (DOC), and iron (Fe) concentrations increased after harvest while the sulfate (SO4-S) concentration decreased. The highest abundances of sulfate-reducing bacteria (SRB) were found on the sites with high MeHg concentrations. The biggest changes in ditch water concentrations occurred first 2 years after harvesting. PMID:26979172

  4. 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 (flood magnitude and noncohesive sandy sediments that collectively minimize development of alluvial bankfull indicators. Collectively, these findings indicate that mixed alluvial–bedrock channels exhibit first-order lithologic controls (lithologic resistance and valley confinement) of channel geometry, second

  5. A field test of the relative influence of sediment flux and grain size in determining bedrock river channel slope

    Science.gov (United States)

    Klier, R. E.; Finnegan, N. J.

    2013-12-01

    , upstream of the knickpoint , Boulder Creek is characterized by potholes and sculpted bedrock, consistent with sediment-starved conditions. The observation that bedrock channel slope changes are not well correlated with patterns in rock uplift supports Sklar and Dietrich's (2006) theoretical result that modest rates of rock uplift do not significantly influence river profile slopes. Based on this result and the clear correlation of channel slope and sediment supply along Boulder Creek, we chose to ignore rock uplift rate and instead explore the relative roles of grain size and sediment flux in influencing profile slopes along Boulder Creek. Using field surveys of grain size and high flow depth, we calculate that across the knickpoint there is a 2-fold increase in the shear stress needed to transport sediment and a 10-fold increase in the shear stress needed to initiate motion. This result implies that changes in sediment supply but most importantly grain size act as a first order control in setting channel slope in mixed bedrock-alluvial systems.

  6. Zn isotopes as a traccer of bedrock weathering in hydrothermal system of la Soufrière volcano, Guadeloupe (FWI)

    Science.gov (United States)

    Chen, J.; Gaillardet, J.; Dessert, C.; Louvat, P.; Villemant, B.; Birck, J.; Crispi, O.

    2012-12-01

    The active hydro-volcanic systems are characterized by intense hydrothermal activities associated with acidic fumaroles and hot springs and play an important role in global silicate weathering. As the ultimate weathering loads are mostly transported into ocean through water, studies of hydrothermal waters can give interesting clues about the complex interactions among magmatic fluids, bed-rock, and aquifers fed by meteoritic water or seawater. Zn is a volatile element during magma degassing. However, the behavior of Zn in hydrothermal water systems is still unclear. Recent studies have demonstrated the interest of Zn isotopes for investigating water-rock interactions. Speciation-related fractionation as well as source-related fractionation between its isotopes (about 3‰ in δ66Zn unit) make Zn isotopes a promising tracer for studying the mobility of metals during weathering, hydrothermalism, magma degassing and ore formation. Although previous studies have focused on the processes fractionating Zn isotopes in hydrothermal solid deposits, seafloor vents and fumarolic gas, Zn isotope composition of hydrothermal waters in continental arc setting has not been investigated so far. We developed a new one-step purification method for the separation of Zn from Fe- and SO4-enriched hydrothermal solutions using anion-exchange column. The protocol was validated by multiple tests on varying eluants and Zn concentrations, and by investigating the recovery and the reproducibility of measured isotopic ratios. Using this method, water samples from 8 hydrothermal springs and 6 gas samples from two fumaroles of la Soufrière active volcano on the Guadeloupe island (French West Indies, FWI) were analyzed for Zn isotope composition. Compared to the small δ66Zn range for the fumarolic gases (from 0.21‰ to 0.35‰) and local bedrocks (from -0.14‰ to 0.42‰), all water samples displayed a relative large δ66Zn variation of 1.44‰ (from -0.43‰ to 1.01‰). This is about 70% of

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

    International Nuclear Information System (INIS)

    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 δ18O 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. - Highlights: • Most Fe and some As exist as particulates in the tested borehole and fracture water.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Qiang [Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9 W, Palisades, NY 10964 (United States); School of Earth and Environmental Sciences, Queens College and Graduate Center, City University of New York, 65-30 Kissena Blvd., Flushing, NY 11367 (United States); Culbertson, Charles W.; Nielsen, Martha G.; Schalk, Charles W. [U.S. Geological Survey, Maine Water Science Center, 196 Whitten Road, Augusta, ME 04330 (United States); Johnson, Carole D. [U.S. Geological Survey, Branch of Geophysics, 11 Sherman Place, Unit 5015, University of Connecticut, Storrs, CT 06269 (United States); Marvinney, Robert G. [Maine Geological Survey, 93 State House Station, Augusta, ME 04333 (United States); Stute, Martin [Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9 W, Palisades, NY 10964 (United States); Zheng, Yan, E-mail: yan.zheng@qc.cuny.edu [Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9 W, Palisades, NY 10964 (United States); School of Earth and Environmental Sciences, Queens College and Graduate Center, City University of New York, 65-30 Kissena Blvd., Flushing, NY 11367 (United States)

    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{sup 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. - Highlights: • Most Fe and some As exist as particulates in the tested borehole and fracture water.

  9. 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. PMID:18258282

  10. Reach-scale evidence for feedbacks among chemical weathering, rock strength and erosion in bedrock rivers across Kohala Peninsula, Hawai'i

    Science.gov (United States)

    Murphy, B. P.; Johnson, J. P.; Gasparini, N. M.; Hancock, G. S.; Small, E. E.

    2015-12-01

    Bedrock river downcutting is usually conceptualized in terms of shear-stress dependent erosion processes, such as abrasion and plucking. Many studies of climatic control on erosion have focused on the effect of rainfall rate on discharge. However, the erodibility of bedrock can also be influenced by climate-dependent chemical weathering. We show that this mechanism can not only influence erosion patterns and rates, but also reach-scale bedrock topography. First, we present a new numerical model that describes and explores the feedbacks among chemical weathering, rock strength and erosion rate. Second, we present reach-scale field data demonstrating interactions among chemical weathering, rock strength, abrasion, and channel morphology. Across an extreme rainfall gradient on Kohala Peninsula, Hawai'i, we demonstrate that bedrock chemical weathering leads to the development of significant asymmetries in rock strength across features that are exposed to abrasion. Using a type-N Schmidt hammer, we measured the in-situ rock strength across 23 morphologic features of bedrock exposed in the stream beds of rivers, and found that upstream faces are consistently stronger, by an average of 38%, than downstream faces. Measured rock strengths suggest that the erodibilty of downstream (lee) faces may be as much as 20 times higher than corresponding upstream faces where weaker weathered material is efficiently abraded away. The asymmetrical pattern of rock strength does not necessarily lead to strongly asymmetrical morphologies, because although sediment impacts may result in more erosion on the weaker downstream face, the frequency of abrasion wear is substantially less frequent. Although the physical evidence for the chemical weathering is more frequently removed from the upstream face, these results demonstrate that, particularly in regions with higher local rainfall and weathering rates, chemical weathering induced strength reduction is a specific mechanism by which climate

  11. 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.

  12. Vegetation and landscape on crystalline limestone bedrock in the vicinity of Lánov (Giant Mountains, Czech Republic

    Directory of Open Access Journals (Sweden)

    Jitka Málková

    2013-12-01

    Full Text Available This paper evaluates the structure of the landscape and vegetation in an area of 106.4 ha near the quarry by the village Horni Lanov (4 km east of Vrchlabi situated in a low part of the Giant Mountains. The bedrock (crystalline limestone, rugged terrain, soil moisture and management affect the biodiversity at this locality. It is botanically well known and a very valuable region because of the high number of nature conservation-important species and habitats that occur there. A total 517 species of vascular plants were recorded there between 2002 and 2010. The whole area was divided into 36 segments each with a relatively homogeneous vegetation cover consisting of particular species of plants. Classification of the segments was done using a numerical classification (Sorensen’s similarity index and Ellenberg’s indicator values were used to describe the basic environmental features of the individual segments. The species presence/ absence data together with indicator values (light conditions, temperature, water availability, soil reaction and nitrogen activity were evaluated. The PCA ordination of this data set distinguished three basic types of vegetation cover (“forest”, “dry” and “wet” and that the species composition of the vegetation in the area is mostly determined by land-use (deforestation, limestone mining, pasturing and management of forests and soil moisture.

  13. Lateral erosion in an experimental bedrock channel: The influence of bed roughness on erosion by bed load impacts

    Science.gov (United States)

    Fuller, Theodore K.; Gran, Karen B.; Sklar, Leonard S.; Paola, Chris

    2016-05-01

    Physical experiments were conducted to evaluate the efficacy of bed load particle impacts as a mechanism of lateral bedrock erosion. In addition, we explored how changes in channel bed roughness, as would occur during development of an alluvial cover, influence rates of lateral erosion. Experimental channels were constructed to have erodible walls and a nonerodible bed using different mixtures of sand and cement. Bed roughness was varied along the length of the channel by embedding sediment particles of different size in the channel bed mixture. Lateral wall erosion from clear-water flow was negligible. Lateral erosion during periods in which bed load was supplied to the channel removed as much as 3% of the initial wetted cross-sectional area. The vertical distribution of erosion was limited to the base of the channel wall, producing channels with undercut banks. The addition of roughness elements to an otherwise smooth bed caused rates of lateral erosion to increase by as much as a factor of 7 during periods of bed load supply. However, a minimum roughness element diameter of approximately half the median bed load particle diameter was required before a substantial increase in erosion was observed. Beyond this minimum threshold size, further increases in the relative size of roughness elements did not substantially change the rate of wall erosion despite changes in total boundary shear stress. The deflection of saltating bed load particles into the channel wall by fixed roughness elements is hypothesized to be the driver of the observed increase in lateral erosion rates.

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

    International Nuclear Information System (INIS)

    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)

  15. Spatially continuous characterization of the bedrock - regolith interface at the Rio Icacos Watershed (Luquillo Critical Zone Observatory) Puerto Rico

    Science.gov (United States)

    Ntarlagiannis, D.; Comas, X.; Wright, W. J.; Recinos, E.; Hynek, S. A.; Brantley, S. L.

    2015-12-01

    Joint processing of geophysical data can enhance data interpretation. This study focuses on spatially continuous multifrequency electro-magnetic (EM) data for near subsurface characterization. Recent advances in EM data processing allow for efficient inversion of multi-frequency data, utilization of calibration routines and additional constrains for better subsurface imaging. For this work the newly developed FEMIC (Frequency-Domain Electromagnetic Inversion Code) code was used to invert the EM data. High resolution electrical resistivity (ER) data were used to calibrate the EM process; additionally, available data from ground penetrating radar (GPR) and field observations were used to better constrain the inversions. The multistep EM processing allowed for improving characterization of the subsurface over long (i.e. Km scale) 2D transects. The aim of this work was to better understand the lateral extent of the bedrock-regolith interface in the Rio Icacos watershed of the Luquillo Critical Zone Observatory (LCZO), while providing evidence for changes in regolith thickness as related to proximity to the nickpoint. This research highlights the advantages of geophysical methods for critical zone studies and their potential for improving spatial characterization of the subsurface at multiples scales. Furthermore it shows the potential of EM methods for translating high resolution spatially limited point measurements (e.g. boreholes) to large (km) scales.

  16. 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.

    2015-07-01

    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.

  17. Review of the sorption data of the main radionuclides in low and intermediate level nuclear wastes for Finnish bedrock

    International Nuclear Information System (INIS)

    This report summarizes the studies on sorption of radionuclides in Finnish bedrock performed at the Department of Radiochemistry University of Helsinki. Sorption data for backfill and construction material are also included. Samples represent common rocks, minerals, construction and backfill materials at the sites in the prposed repositories for low and intermediate level nuclear wastes at Haestholmen (IVO) and Olkiluoto (TVO). Sample types used for sorption experiments were crushed rock and concrete, mineral and rock thin sections, rock pieces, 'drill core cups' and natural fracture surfaces. The method used for determination of Ksub(d)-values was the batch method. The determination of Ksub(a)-values was performed by the autoradiographic method. The radionuclides discussed in this report are 134Cs, 85Sr, 89Sr, 58Co, 63Ni, 125I, 99Tc and 14C. Recommended sorption data (Ksub(d) and Ksub(a)-values) for use in safety analyses in migration modelling are presented. For conservative evaluation the values selected are minimum values from two or three parallel determinations. When only one Ksub(a)-value of radionuclide was available for a rock species that value was considered as recommended value. (author)

  18. Bacterial community composition in relation to bedrock type and macrobiota in soils from the Sør Rondane Mountains, East Antarctica.

    Science.gov (United States)

    Tytgat, Bjorn; Verleyen, Elie; Sweetlove, Maxime; D'hondt, Sofie; Clercx, Pia; Van Ranst, Eric; Peeters, Karolien; Roberts, Stephen; Namsaraev, Zorigto; Wilmotte, Annick; Vyverman, Wim; Willems, Anne

    2016-09-01

    Antarctic soils are known to be oligotrophic and of having low buffering capacities. It is expected that this is particularly the case for inland high-altitude regions. We hypothesized that the bedrock type and the presence of macrobiota in these soils enforce a high selective pressure on their bacterial communities. To test this, we analyzed the bacterial community structure in 52 soil samples from the western Sør Rondane Mountains (Dronning Maud Land, East Antarctica), using the Illumina MiSeq platform in combination with ARISA fingerprinting. The samples were taken along broad environmental gradients in an area covering nearly 1000 km(2) Ordination and variation partitioning analyses revealed that the total organic carbon content was the most significant variable in structuring the bacterial communities, followed by pH, electric conductivity, bedrock type and the moisture content, while spatial distance was of relatively minor importance. Acidobacteria (Chloracidobacteria) and Actinobacteria (Actinomycetales) dominated gneiss derived mineral soil samples, while Proteobacteria (Sphingomonadaceae), Cyanobacteria, Armatimonadetes and candidate division FBP-dominated soil samples with a high total organic carbon content that were mainly situated on granite derived bedrock. PMID:27402710

  19. Inventory of clay-rich bedrock and metamorphic derivatives in eastern Nevada, excluding the Nevada Test Site

    International Nuclear Information System (INIS)

    Six counties of eastern Nevada contain 36 localities that include areas of exposed clay-rich sedimentary bedrock, slightly to moderately metamorphosed derivatives of such rocks, or both. In each locality one or more of these kinds of rocks constitute one or more geologic units greater than 152 m (500 ft) in thickness and 0.8 km2 (0.3 m2) in area at the ground surface. The sedimentary and metamorphic rocks locally meet or exceed arbitrarily selected minimum conditions of lithology, thickness, and areal extent. These places are grouped into localities and may be deemed suitable for further investigation. The localities identified are in Clark, Elko, Eureka, Lincoln, Nye, and White Pine Counties. The types of clay-rich rocks that might be useful include claystone, siltstone, shale, and various mixtures of them, together with metamorphic derivatives which include argillite, metasiltstone, slate, phyllite, schist, and gneiss. The geologic units that contain such clay-rich rocks also commonly contain mixtures, interlayers, and lenses of sandstone, conglomerate, and limestone, and their metamorphic derivatives: quartzite, conglomerite, and marble. Initially, the principal areas in Nevada where clay-rich rocks more than 31 m (100 ft) thick are exposed at the ground surface were identified by searching published geologic literature. From those areas, localities that contain exposed clay-rich rocks more than 152 m (500 ft) thick and of more than 0.8 km2 (0.3 mi2) in areas were selected. For each locality a brief descriptive text was prepared. Seven factors that might be significant in selecting localities best suited for further investigation are summarized therein. The factors are: (1) geographic location, (2) land ownership, (3) accessibility, (4) proximity to population concentration, (5) geologic setting, (6) hydrologic setting, and (7) mineral-resource activity

  20. Highly Resolved Long-term 3D Hydrological Simulation of a Forested Catchment with Litter Layer and Fractured Bedrock

    Science.gov (United States)

    Fang, Z.; Bogena, H. R.; Kollet, S. J.; Vereecken, H.

    2014-12-01

    Soil water content plays a key role in the water and energy balance in soil, vegetation and atmosphere systems. According to Wood et al. (2011) there is a grand need to increase global-scale hyper-resolution water-energy-biogeochemistry land surface modelling capabilities. However, such a model scheme should also recognize the epistemic uncertainties, as well as the nonlinearity and hysteresis in its dynamics. Unfortunately, it is not clear how to parameterize hydrological processes as a function of scale and how to test deterministic models with regard to epistemic uncertainties. In this study, high resolution long-term simulations were conducted in the highly instrumented TERENO hydrological observatory, the Wüstebach catchment. Soil hydraulic parameters were derived using inverse modeling with the Hydrus-1D model using the global optimization scheme SCE-UA and soil moisture data from a wireless soil moisture sensor network. The estimated parameters were then used for 3D simulations using the integrated parallel simulation platform ParFlow-CLM. The simulated soil water content, as well as evapotranspiration and runoff, were compared with long-term field observations to illustrate how well the model was able to reproduce the water budget dynamics. With variable model setup scenarios in boundary conditions and anisotropy of hydraulic conductivity, we investigated how lateral flow processes above the underlying fractured bedrock affects the simulation results. Furthermore, we explored the importance of the litter layer and the heterogeneity of the forest soil in the simulation of flow processes and model performance. For the analysis of spatial patterns of simulated and observed soil water content we applied the method of empirical orthogonal function (EOF). The results suggest that strong anisotropy in the hydraulic conductivity may be the reason for the fast lateral flow observed in Wüstebach. Introduction of heterogeneity in the hydraulic properties in the

  1. Lead isotope distribution in podzolic soil profiles on different types of bedrock in a formerly glaciated terrain (Oslo, Norway)

    Energy Technology Data Exchange (ETDEWEB)

    Saether, O.M., E-mail: ola.sather@ngu.no [Geological Survey of Norway, Leiv Eirikssons vei 39, NO-7094 Trondheim (Norway); Aberg, G. [Laboratory for Isotope Geology, Box 50007, SE-104 05 Stockholm (Sweden); Steinnes, E. [Department of Chemistry, NTNU, NO-7491 Trondheim (Norway)

    2011-06-15

    Highlights: > Four sites with different lithology (syenite, gneiss, granite, sedimentary rocks), formerly glaciated terrain, Oslo, Norway. > Variations with depth of grain-size, total organic C, Pb concentration, Pb isotope ratio. > Content of anthropogenic Pb in podzolic forest soil. > Comparison of three methods for calculating anthropogenic Pb input. > Amounts of anthropogenic Pb in upper 20 cm calculated to be 1-6 t/km{sup 2}. - Abstract: Lead has been exploited by man over thousands of years for a variety of metallurgical, medicinal, and industrial purposes. The cumulative output of Pb from mining is estimated to be 260 million metric tonnes and 85% of this has occurred over the last two centuries. Global annual production of Pb from mining was about 3 million tonnes at the turn of the millenium. Terrestrial ecosystems all over Norway have been contaminated moderately to strongly by Pb and other trace elements from atmospheric deposition. With the aim of developing a method for mapping the accumulated content of anthropogenic Pb and how deep in the soil profile the atmospherically deposited Pb has penetrated, the concentration of Pb and the {sup 206}Pb/{sup 207}Pb ratio has been studied in podzolic forest soils at four locations with different lithology, i.e. age and type of bedrock, in the Oslo area. The concentrations of Pb in the soil profiles are 6.6-38.1 mg/kg (median 10.3). The {sup 206}Pb/{sup 207}Pb ratio ranges between 1.168 and 1.314 (median 1.267) over the entire profile. In the upper 5 cm the range is 1.168-1.191, similar to ratios determined in recent atmospheric deposition. Applying three different methods, the amount of anthropogenically deposited Pb is estimated at 1-6 t/km{sup 2}.

  2. 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.

  3. Investigation of the relationship between ground and engineering bedrock at northern part of the Gulf of İzmir by borehole data supported geophysical works

    Indian Academy of Sciences (India)

    Mustafa Akgün; Tolga Gönenc; Oya Pamukçu; Şenol Özyalin

    2014-04-01

    Loss of life and property that may occur as a result of a possible earthquake can be reduced by earthquake resistant building designs. In order to investigate possible ground motion amplification in earthquake resistant building design, relationship between the ground and engineering bedrock must be ensured. In order to provide this relation, structure, basic characteristics, and thickness of the ground are investigated. In this context, calculating ground transfer function, obtaining horizontal earthquake acceleration changes, calculating values and defining the engineering bedrock are necessary. In this study, Menemen plain, the nothern part of Izmir metropolitan located in active earthquake zone and its immediate vicinity have been examined to define the structure, ground, engineering and bedrock relation. In this context, Menemen plain has been investigated by geophysical methods, which are supported with borehole data (microtremor, MASW – multichannel analysis of surface waves, microgravity measurements, and vertical electrical sounding – VES). Microtremor method was conducted at 377 points in average in the investigation area to define fundamental period and empirical transfer function; after that in order to create basin model and to define the shallow subsurface geometry, microgravity measurements were carried out by using Scintrex CG-5. Also, MASW measurements were carried out in approximately 277 profiles and Schlumberger VES measurements were conducted at approximately 7 points in the investigation area. The existence of a linear relation between H/V peak period values obtained by microtremor measurements and ground thickness in the investigation area is also supported by geothermal drilling logs (depth of 600 m) with microgravity survey. Also, in some parts of the investigation area, it was observed that high velocity () values affected H/V peak period values in sections of the ground close to the surface and there was an inversely correlated

  4. 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, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, was produced all or in part from Field Survey/GPS information as of 1998. It is described as 'Tabular data involving the location of...

  5. Geology, Bedrock, Paint Rock Quad unit polygons. Compiled Polygons., Published in 2006, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2006. It is described as...

  6. Geology, Bedrock, Geologic map of the Triassic portion of the Cary 7.5-minute quadrangle., Published in 1999, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Field Observation information as of 1999. It is described...

  7. Unpublished Digital Bedrock Geologic Map of Cuyahoga National Park and Vicinity, Ohio (NPS, GRD, GRI, CUVA, CUVA digital map) adapted from Ohio Division of Geological Survey maps by Larsen and/or Slucher, and/or others (1996)

    Data.gov (United States)

    National Park Service, Department of the Interior — The Unpublished Digital Bedrock Geologic Map of Cuyahoga National Park and Vicinity, Ohio is composed of GIS data layers complete with ArcMap 9.3 layer (.LYR)...

  8. Geology, Bedrock, Geologic Map of the North Carolina Portion of the Gasburg Quadrangle (Mapping by USGS), Published in 2004, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2004. It is described as...

  9. Geology, Bedrock, Geologic Map of the North Carolina Portion of the Clarksville South Quadrangle (Mapping by USGS), Published in 2004, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2004. It is described as...

  10. Geology, Bedrock, Persimmon Creek Quad line work. Incomplete lines., Published in 2006, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2006. It is described as...

  11. Geology, Bedrock, Mars Hill Quad unit polygons. Compiled Polygons., Published in 2006, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Hardcopy Maps information as of 2006. It is described as...

  12. Geology, Bedrock, Geologic map of the Southeast Durham 7.5-minute quadrangle., Published in 1999, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Field Observation information as of 1999. It is described...

  13. Geology, Bedrock, Geologic Map of the Chapel Hill Quadrangle, Published in 2004, 1:24000 (1in=2000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Field Observation information as of 2004. It is described...

  14. Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 1. Depth to Bedrock Determinations Using Shallow Seismic Data Acquired in the Straight Creek Drainage Near Red River, New Mexico

    Science.gov (United States)

    Powers, Michael H.; Burton, Bethany L.

    2004-01-01

    In late May and early June of 2002, the U.S. Geological Survey (USGS) acquired four P-wave seismic profiles across the Straight Creek drainage near Red River, New Mexico. The data were acquired to support a larger effort to investigate baseline and pre-mining ground-water quality in the Red River basin (Nordstrom and others, 2002). For ground-water flow modeling, knowledge of the thickness of the valley fill material above the bedrock is required. When curved-ray refraction tomography was used with the seismic first arrival times, the resulting images of interval velocity versus depth clearly show a sharp velocity contrast where the bedrock interface is expected. The images show that the interpreted buried bedrock surface is neither smooth nor sharp, but it is clearly defined across the valley along the seismic line profiles. The bedrock models defined by the seismic refraction images are consistent with the well data.

  15. 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. PMID:15449861

  16. 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.

  17. The true geodynamics of Fennoscandia, the insanity of a final unguarded bedrock deposition, and the possibility to use the Drd-method

    International Nuclear Information System (INIS)

    For 20 years it has been claimed by the Swedish and Finnish nuclear agencies (KBS, SKB, TVO etc.) that we are in the possession of a safe method for the final deposition of high-level nuclear waste. By 'safe' they mean full guarantees for the immense time period of 'many hundreds of thousands of years' By 'final', they mean that the waste is left by itself in the bedrock at a depth of 500 m, without any control and without any real means of retrieval. For 20 years, Moerner has claimed that this is sheer nonsense. No one can give such guarantees over such long time periods. Furthermore, the geodynamic facts give a totally different picture. Our Precambrian crystalline bedrock is, by no means, as stable and reliable as claimed. Only some 10,000 years back in time, the seismic activity was tremendously high, in amplitude as well as in frequency. In such an environment - to be repeated at the next future ice age (estimated to occur 5,000 AP, 23,000 AP and 70,000 AP) - we can, of course, give no guarantees for a waste disposal in the bedrock, on the contrary, most facts suggest that it would be seriously damaged. We have disclosed the occurrence of an immense earthquake in the autumn 10,430 varve years BP. The liquefaction structures of this event seem to cover an area larger than the famous 1964 earthquake in Alaska. By studies of seismites in the glacial varves, we have shown that there, in the Stockholm area, were four (maybe more) events with a time spacing only of some 20 varves indicating a very high frequency of seismic events. Bedrock caves (Boda, Gillberga, Torekulla, etc.) and post glacially fractured bedrock hills and surfaces occur all over the country. Their genesis is not yet fully understood. They may be the effects of earthquakes or, even worse, the result of methane venting. Under all circumstances, their mere occurrence precludes any claim of total, long-term safety for a bedrock repository. We will report on our first findings regarding a major paleo

  18. Recharge to Shale Bedrock at Averill Park, an Upland Hamlet in Eastern New York - An Estimate Based on Pumpage within a Defined Cone of Depression

    Science.gov (United States)

    Randall, Allan D.; Finch, Anne

    2008-01-01

    Water levels beneath parts of Averill Park, a residential hamlet in an upland area of till-mantled shale bedrock in east-central New York, have declined in response to increased withdrawals from new wells. Similar experiences in many upland localities in the northeastern United States have resulted in awareness that the rate of recharge to bedrock can be an important constraint on the density of new development in uplands. Recharge at Averill Park was calculated on the basis of careful estimation of pumpage within a defined cone of depression. The data-collection and recharge-estimation procedures documented herein could be applied in a variety of upland localities in support of community-planning studies. Static water levels measured in 145 wells at Averill Park during the late summer of 2002 defined a 0.54-square-mile cone of depression within which ground-water discharge took place entirely as withdrawals from wells. Rates of withdrawal were estimated largely from surveys in similar neighborhoods a few miles away served by public water supply. Comparison of the water-level measurements in 2002 with measurements on other dates revealed localized declines that could be attributed to new housing developments or commercial demands, but also demonstrated that water levels in 2002 within the cone of depression had stabilized and were not declining persistently over time. Therefore, the current withdrawals were equated to recharge from infiltrating precipitation. Recharge within this area was estimated to average 104 gallons per day per acre, equivalent to 1.4 inches annually, and was sufficient to sustain a residential population of 1.9 persons per acre. This recharge rate is much lower than rates estimated from streamflow records for upland watersheds elsewhere in the northeastern United States. This rate is an average of an unknown larger rate in the 30 percent of the study area where bedrock is discontinuously overlain by less than 30 feet of till and an unknown

  19. Modeling the mobility of uranium from NORM-rich bedrock using multivariate statistical techniques - The mobility of uranium from U-containing bedrock materials as a function of pH: Implications for tunnel construction

    International Nuclear Information System (INIS)

    According to amendments made to the Norwegian Pollution Control Act in 2011, naturally occurring radioactive material is now to be considered as an environmental contaminant, in addition to organic pollutants and trace metals. Environmental contamination is strongly correlated with the mobility and bioavailability of metals and radionuclides in natural systems. In order to determine the risk of environmental contamination from e.g. uranium (U) in alum shale areas, it is of particular importance to determine the mobility of U and trace metals found in the rock materials and their binding mechanisms. By determining the speciation and mobility of uranium and trace metals, better predictions can be made on the transport of contaminants in the environment from intervention like road and tunnel construction. The substrate media analyzed in this work was collected from a future tunnel construction site that is being built in the Gran municipality on National road Rv4 in Norway. The bedrock in the Gran municipality is rich in U-bearing minerals. Therefore, there is high potential for environmental contamination from the rock material removed for tunnel construction purposes. The present work focuses upon the effects of pH and the contact time (substrate media: solution) on the mobility of uranium. In order to identify the effects of pH and contact time on mobility, sample cores collected from an area rich in alum shale were subjected to an extended leaching experiment. In this experiment, the substrate materials were treated with five different pH solutions and were analyzed for different contact times. In addition, the results were compared to data from a sequential extraction experiment. In the leaching experiment, the mobilization of uranium in all of the substrate material was affected by the pH of solution. All of the samples were capable of quickly buffering pH solutions with a pH as low as 4 to neutral-alkaline conditions, attributed to the carbonate minerals

  20. Modeling the mobility of uranium from NORM-rich bedrock using multivariate statistical techniques - The mobility of uranium from U-containing bedrock materials as a function of pH: Implications for tunnel construction

    Energy Technology Data Exchange (ETDEWEB)

    Helmers, Tari; Fjermestad, Halldis; Salbu, Brit; Skipperud, Lindis [Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas (Norway); Meland, Sondre; Hagelia, Per [Norwegian Public Roads Administration, P.O. Box 8142, 0033 Oslo (Norway)

    2014-07-01

    According to amendments made to the Norwegian Pollution Control Act in 2011, naturally occurring radioactive material is now to be considered as an environmental contaminant, in addition to organic pollutants and trace metals. Environmental contamination is strongly correlated with the mobility and bioavailability of metals and radionuclides in natural systems. In order to determine the risk of environmental contamination from e.g. uranium (U) in alum shale areas, it is of particular importance to determine the mobility of U and trace metals found in the rock materials and their binding mechanisms. By determining the speciation and mobility of uranium and trace metals, better predictions can be made on the transport of contaminants in the environment from intervention like road and tunnel construction. The substrate media analyzed in this work was collected from a future tunnel construction site that is being built in the Gran municipality on National road Rv4 in Norway. The bedrock in the Gran municipality is rich in U-bearing minerals. Therefore, there is high potential for environmental contamination from the rock material removed for tunnel construction purposes. The present work focuses upon the effects of pH and the contact time (substrate media: solution) on the mobility of uranium. In order to identify the effects of pH and contact time on mobility, sample cores collected from an area rich in alum shale were subjected to an extended leaching experiment. In this experiment, the substrate materials were treated with five different pH solutions and were analyzed for different contact times. In addition, the results were compared to data from a sequential extraction experiment. In the leaching experiment, the mobilization of uranium in all of the substrate material was affected by the pH of solution. All of the samples were capable of quickly buffering pH solutions with a pH as low as 4 to neutral-alkaline conditions, attributed to the carbonate minerals

  1. Characterization of DNAPL Source Zone Arcgitecture in Clay Till and Limestone Bedrock by Integrated Site Investigations with Innovative and Current Techniques

    DEFF Research Database (Denmark)

    Broholm, Mette Martina; Janniche, Gry Sander; Fjordbøge, Annika Sidelmann;

    facility for perchloroethene (PCE) and trichloroethene (TCE) at the Naverland site near Copenhagen, Denmark, has resulted in PCE and TCE DNAPL impacts to a fractured clay till and an underlying fractured limestone aquifer/bedrock. A range of innovative and current site investigative tools for direct and...... discrete subsampling for quantitative analysis, SudanIV hydrophobic colour test, colour spray test, PID and geologic descriptions; NAPL and FACT FLUTe exposure and discrete FACT subsampling and analysis; liquid sampling from boreholes; and a radon and PCE/TCE soil gas survey. Investigations in the...

  2. Hydrogeological Importance of Bedrock Sediments to the Community and Growth of Sugar Cane in Fadama Rake Area of Madagali, Northeast Nigeria

    Directory of Open Access Journals (Sweden)

    Gaiya Stephen

    2014-04-01

    Full Text Available Thirty Vertical Electrical Sounding (VES points were sited on the alluvial plain of Madagali fadama area. This was aimed at establishing the lithological character of the drainage plain and its contributions to the growth of sugar cane. 1X1D shareware package was used to interpret the curves. Over the floodplain, potential recharge water into the subsurface units probably takes place through migration routes of coarse-grained colluvial deposits which act as effective soak away for surface runoff. The nature of the basin and/or the transporting routes conditioned the thickness of the surface layer. Effects of near surface bedrock or buried granite boulders disengaged from nearby hills are demonstrated by sandwiching of the bedrock in place in the second resistivity layer. Closely spaced iso-ohmic contour values suggest presence of different types of sediments within the medium of deposition. The high thickness associated with this horizon suggests that the basin was large enough to contain the sediments. Clay materials in the third resistivity layer occur as lens bodies within sandy material. Clay free sand and gravel constitute a great proportion of the stratigraphy. Parts of the bedrock’s summits that approached the surface at two separate places are resistant to weathering. Thicker sediments were available where sandy and gravelly materials prevailed. Gradual increases in thickness of the sediments suggest a gentle sloping depositional basin. Sharp gradation of the grain size from clay to bedrock within the fourth resistivity layer depicts a basin that did not permit transportation of the material far from its source. Three zones of groundwater potentials were identified from the total longitudinal conductance and the porosity maps of the area. These were based on the weathered products that constitute the aquifer zone where thick saturated sand and gravel are associated to deep aquifer development and thin saturated sand and gravel to

  3. Planning of in-situ experiment for understanding of gas migration behaviour in sedimentary rock. (2) Affects of dissolved methane to the gas migration in bedrock

    International Nuclear Information System (INIS)

    Japan Atomic Energy Agency has been planning in-situ gas migration test in Horonobe URL, Hokkaido. It is expected that dissolved methane in Horonobe groundwater might have an effect on gas migration behaviour in bedrock. A series of two-phase multi-component analyses by use of GETFLOWS were conducted to understand the influence of dissolved methane. The increase of total gas pressure has been shown due to the existence of dissolved methane. The results also indicated that the injected nitrogen gas volume was influenced by dissolved methane. (author)

  4. Investigation of the effect of high frequency excited tools by the treatment of bedrock; Untersuchungen zur Wirkung hochfrequent erregter Werkzeuge bei der Zerstoerung von Festgestein

    Energy Technology Data Exchange (ETDEWEB)

    Kunze, Guenter; Ebenhan, Karsten [Technische Univ. Dresden (Germany). Lehrstuhl fuer Baumaschinen- und Foerdertechnik; Lieberwirth, Holger [TAKRAF GmbH, Lauchhammer (Germany)

    2011-01-15

    Only in Germany mobile work machines consume about 1.6 Mio. t of diesel fuel per year. This kind of machinery is responsible for 47.8% of the CO{sub 2} emission and 60% of the NO{sub x} emission of all power driven vehicles in Germany. Economic competition as well as the aims of energy policy demand more economical machines and procedures. This can be realised only by new technologies. A starting point to lower the fuel consumption is to optimise the primary energy demand in the digging process of bedrock by a new approach. (orig.)

  5. Detecting the near-surface redox front in crystalline bedrock using fracture mineral distribution, geochemistry and U-series disequilibrium

    International Nuclear Information System (INIS)

    Oxidizing conditions normally prevail in surface waters and near-surface groundwaters, but there is usually a change to reducing conditions in groundwater at greater depth. Dissolved O2 originally present is consumed through biogenic and inorganic reactions along the flow paths. Fracture minerals participate in these reactions and the fracture mineralogy and geochemistry can be used to trace the redox front. An important task in the safety assessment of a potential repository for the disposal of nuclear waste in crystalline bedrock, at an approximate depth of 500 m in Sweden, is to demonstrate that reducing conditions can be maintained for a long period of time. Oxygen may damage the Cu canisters that host nuclear waste; additionally, in the event of a canister failure, oxidizing conditions may increase the mobility of some radionuclides. The present study of the near-surface redox front is based on mineralogical (redox-sensitive minerals), geochemical (redox-sensitive elements) and U-series disequilibrium investigations of mineral coatings along open fractures. The fractures have been sampled along drill cores from closely spaced, 100 m deep boreholes, which were drilled during the site investigation work in the Laxemar area, south-eastern Sweden, carried out by the Swedish Nuclear Fuel and Waste Management Co. (SKB). The distribution of the redox-sensitive minerals pyrite and goethite in open fractures shows that the redox front (switch from mainly goethite to mainly pyrite in the fractures) generally occurs at about 15-20 m depth. Calcite leaching by recharging water is indicated in the upper 20-30 m and positive Ce-anomalies suggest oxidation of Ce down to 20 m depth. The U-series radionuclides show disequilibrium in most of the samples, indicating mobility of U during the last 1 Ma. In the upper 20 m, U is mainly removed (due to oxidation) or has experienced complex removal and/or deposition. At depths of 35-55 m, both deposition and removal of U are indicated

  6. Use of Bedrock and Geomorphic Mapping Compilations in Assessing Geologic Hazards at Recreation Sites on National Forests in NW California

    Science.gov (United States)

    de La Fuente, J. A.; Bell, A.; Elder, D.; Mowery, R.; Mikulovsky, R.; Klingel, H.; Stevens, M.

    2010-12-01

    Geologic hazards on US Forest Service lands have a long history of producing catastrophic events. In 1890 (prior to the establishment of the Forest Service), the China Mine landslide buried a miner’s camp along the Trinity River in NW California, killing a number of miners. An earthquake in southwestern Montana triggered a massive landslide which killed 28 people in a US Forest Service campground in 1959. In 1980, Mount St. Helens erupted in Oregon, killing 57 people. Debris flows from a winter storm in 2003 on the burned hillslopes of the San Bernardino National Forest in California killed 14 people at the St. Sophia youth Camp. A rockfall in the summer of 2009 in Lassen National Park killed a 9 year old boy. The most recent catastrophe occurred on June 11, 2010 when 20 people died in a flash flood at the Albert Pike Campground on the Ouachita National Forest. These and other disasters point out the need for geologic hazard mapping and assessments on the National Forests. The US Forest Service (USFS) is currently assessing geologic hazards in the Northern Province of USFS Region 5 (Pacific Southwest Region), which includes the Klamath, Mendocino, Shasta-Trinity, and Six Rivers National Forests. The most common geologic hazards (relatively short return intervals) in this area include landslides, rock falls, debris flows, flooding, temporary dam failures (landslide or woody debris), naturally occurring hazardous materials, (asbestos radon, etc), and rarely, karst subsidence. Seismic and volcanic hazards are also important at longer return intervals. This assessment will be conducted in three phases, and is patterned after a process developed by Region 8 of the US Forest Service. The first phase is a reconnaissance level assessment based on existing information such as spatial databases, aerial photos, Digital Elevation Models, State of California Alquist-Priolo Earthquake Fault Zone maps, previous investigations and anecdotal accounts of past events. The bedrock

  7. Arsenic, iron, lead, manganese, and uranium concentrations in private bedrock wells in southeastern New Hampshire, 2012-2013

    Science.gov (United States)

    Flanagan, Sarah M.; Belaval, Marcel; Ayotte, Joseph D.

    2014-01-01

    nonhealth guidelines—based on aesthetic considerations, such as taste or the staining of laundry and plumbing fixtures—because these contaminants, at the SMCLs, are not considered to present risks to human health. Because lead (Pb) contamination of drinking water typically results from corrosion of plumbing materials belonging to water-system customers but still poses a risk to human health, the EPA established an action level (AL) of 15 μg/L for Pb instead of an MCL or SMCL (U.S. Environmental Protection Agency, 2012). The 15-μg/L AL for Pb has been adopted by the New Hampshire Department of Environmental Services for public water systems, and if exceeded, the public water system must inform their customers and undertake additional actions to control corrosion in the pipes of the distribution system (New Hampshire Department of Environmental Services, 2013). Unlike the quality of drinking water provided by public water suppliers, the quality of drinking water obtained from private wells in New Hampshire is not regulated; consequently, private wells are sampled only when individual well owners voluntarily choose to sample them. The U.S. Geological Survey (USGS), in cooperation with the EPA New England, conducted an assessment in 2012–13 to provide private well owners and State and Federal health officials with information on the distribution of trace-metal (As, Fe, Pb, Mn, and U) concentrations in groundwater from bedrock aquifers in the three counties of southeastern New Hampshire. This fact sheet analyzes data from water samples collected by a randomly selected group of private well owners from the three-county study area and describes the major findings for trace-metal concentrations.

  8. 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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    An up-to-date topic with which engineering geology can contribute to the requirements of practice and research, in particular the needs of land use planning, state administration, building offices, developers, etc. is an analysis of new possibilities of providing reference information on the engineering-geological conditions by means of geographic information systems. The study in the presented paper deals with an evaluation of two geofactors. They are the character of rocks workability and Pre-quaternary bedrock. Workability is a significant limiting factor, which affects the used technology and financial demands of earth work. Especially in case of demanding constructions, the Pre-quaternary bedrock is a geological environment which will have to be interacted with and must be taken into account during selecting engineering foundation. The overall project was divided into five model areas (1-5), while this paper evaluates a 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 Slezske, Moravske Ostravy, Vitkovic a Radvanice. The mentioned methodology was applied in the interest area for the first time. (authors)

  12. 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.).

  13. 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

  14. Difference of brightness temperatures between 19.35 GHz and 37.0 GHz in CHANG'E-1 MRM: implications for the burial of shallow bedrock at lunar low latitude

    Science.gov (United States)

    Yu, Wen; Li, Xiongyao; Wei, Guangfei; Wang, Shijie

    2016-03-01

    Indications of buried lunar bedrock may help us to understand the tectonic evolution of the Moon and provide some clues for formation of lunar regolith. So far, the information on distribution and burial depth of lunar bedrock is far from sufficient. Due to good penetration ability, microwave radiation can be a potential tool to ameliorate this problem. Here, a novel method to estimate the burial depth of lunar bedrock is presented using microwave data from Chang'E-1 (CE-1) lunar satellite. The method is based on the spatial variation of differences in brightness temperatures between 19.35 GHz and 37.0 GHz (ΔTB). Large differences are found in some regions, such as the southwest edge of Oceanus Procellarum, the area between Mare Tranquillitatis and Mare Nectaris, and the highland east of Mare Smythii. Interestingly, a large change of elevation is found in the corresponding region, which might imply a shallow burial depth of lunar bedrock. To verify this deduction, a theoretical model is derived to calculate the ΔTB. Results show that ΔTB varies from 12.7 K to 15 K when the burial depth of bedrock changes from 1 m to 0.5 m in the equatorial region. Based on the available data at low lunar latitude (30°N-30°S), it is thus inferred that the southwest edge of Oceanus Procellarum, the area between Mare Tranquillitatis and Mare Nectaris, the highland located east of Mare Smythii, the edge of Pasteur and Chaplygin are the areas with shallow bedrock, the burial depth is estimated between 0.5 m and 1 m.

  15. Difference of brightness temperatures between 19.35 GHz and 37.0 GHz in CHANG'E-1 MRM: implications for the burial of shallow bedrock at lunar low latitude

    Institute of Scientific and Technical Information of China (English)

    Wen YU; Xiongyao LI; Guangfei WEI; Shijie WANG

    2016-01-01

    Indications of buried lunar bedrock may help us to understand the tectonic evolution of the Moon and provide some clues for formation of lunar regolith.So far,the information on distribution and burial depth of lunar bedrock is far from sufficient.Due to good penetration ability,microwave radiation can be a potential tool to ameliorate this problem.Here,a novel method to estimate the burial depth of lunar bedrock is presented using microwave data from Chang'E-1 (CE-1) lunar satellite.The method is based on the spatial variation of differences in brightness temperatures between 19.35 GHz and 37.0 GHz (△TB).Large differences are found in some regions,such as the southwest edge of Oceanus Procellarum,the area between Mare Tranquillitatis and Mare Nectaris,and the highland east of Mare Smythii.Interestingly,a large change of elevation is found in the corresponding region,which might imply a shallow burial depth of lunar bedrock.To verify this deduction,a theoretical model is derived to calculate the △TB.Results show that △TB varies from 12.7 K to 15 K when the burial depth of bedrock changes from 1 m to 0.5 m in the equatorial region.Based on the available data at low lunar latitude (30°N-30°S),it is thus inferred that the southwest edge of Oceanus Procellarum,the area between Mare Tranquillitatis and Mare Nectaris,the highland located east of Mare Smythii,the edge of Pasteur and Chaplygin are the areas with shallow bedrock,the burial depth is estimated between 0.5 m and 1 m.

  16. 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

  17. Characterizing Hydraulic Properties and Ground-Water Chemistry in Fractured-Rock Aquifers: A User's Manual for the Multifunction Bedrock-Aquifer Transportable Testing Tool (BAT3)

    Science.gov (United States)

    Shapiro, Allen M.

    2007-01-01

    A borehole testing apparatus has been designed to isolate discrete intervals of a bedrock borehole and conduct hydraulic tests or collect water samples for geochemical analyses. This borehole testing apparatus, referred to as the Multifunction Bedrock-Aquifer Transportable Testing Tool (BAT3), includes two borehole packers, which when inflated can form a pressure-tight seal against smooth borehole walls; a pump apparatus to withdraw water from between the two packers; a fluid-injection apparatus to inject water between the two packers; pressure transducers to monitor fluid pressure between the two packers, as well as above and below the packers; flowmeters to monitor rates of fluid withdrawal or fluid injection; and data-acquisition equipment to record and store digital records from the pressure transducers and flowmeters. The generic design of this apparatus was originally discussed in United States Patent Number 6,761,062 (Shapiro, 2004). The prototype of the apparatus discussed in this report is designed for boreholes that are approximately 6 inches in diameter and can be used to depths of approximately 300 feet below land surface. The apparatus is designed to fit in five hard plastic boxes that can be shipped by overnight freight car-riers. The equipment can be assembled rapidly once it is removed from the shipping boxes, and the length of the test interval (the distance between the two packers) can be adjusted to account for different borehole conditions without reconfiguring the downhole components. The downhole components of the Multifunction BAT3 can be lowered in a borehole using steel pipe or a cable; a truck mounted winch or a winch and tripod can be used for this purpose. The equipment used to raise and lower the downhole components of the Multifunction BAT3 must be supplied on site, along with electrical power, a compressor or cylinders of compressed gas to inflate the packers and operate downhole valves, and the proper length of tubing to connect the

  18. Bedrock geology of snyderville basin: Structural geology techniques applied to understanding the hydrogeology of a rapidly developing region, Summit County, Utah

    Science.gov (United States)

    Keighley, K.E.; Yonkee, W.A.; Ashland, F.X.; Evans, J.P.

    1997-01-01

    The availability of ground water is a problem for many communities throughout the west. As these communities continue to experience growth, the initial allocation of ground water supplies proves inadequate and may force restrictions on existing, and future, development plans. Much of this new growth relies on ground water supplies extracted from fractured bedrock aquifers. An example of a community faced with this problem is western Summit County, near Park City, Utah, This area has experienced significant water shortages coupled with a 50% growth rate in the past 10-15 years. Recent housing development rests directly on complexly deformed Triassic to Jurassic sedimentary rocks in the hanging wall of the Mount Raymond-Absaroka thrust system. The primary fractured bedrock aquifers are the Nugget Sandstone, and limestones in the Thaynes and Twin Creek Formations. Ground water production and management strategies can be improved if the geometry of the structures and the flow properties of the fractured and folded bedrock can be established. We characterize the structures that may influence ground water flow at two sites: the Pinebrook and Summit Park subdivisions, which demonstrate abrupt changes (less than 1 mi/1.6 km) within the hydrogeologic systems. Geologic mapping at scales of 1:4500 (Pinebrook) and 1:9600 (Summit Park), scanline fracture mapping at the outcrop scale, geologic cross sections, water well data, and structural analysis, provides a clearer picture of the hydrogeologic setting of the aquifers in this region, and has been used to successfully site wells. In the Pinebrook area, the dominate map-scale structures of the area is the Twomile Canyon anticline, a faulted box-like to conical anticline. Widely variable bedding orientations suggest that the fold is segmented and is non-cylindrical and conical on the western limb with a fold axis that plunges to the northwest and also to the southeast, and forms a box-type fold between the middle and eastern

  19. Levels of potassium, uranium, thorium and rate of radiogenic heat production in the bedrock adjacent to Camamu and Almada sedimentary basins, Bahia, Brazil

    International Nuclear Information System (INIS)

    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 -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 μW m-3, 0,23 to 5,55 μW m-3 and 0,60 to 2,24 μW m-3, respectively. In this case, the heat production rates vary from 0,10 to 1,44 μW m-3. The basic granulites have the smaller rates, from 0,06 to 0,36 μW 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 μW m-3 for metatonalites, 0,71 +- 0,57 μW m-3 for metamonzonites and 1,20 +- 0,51 μW m-3 for sienites. (author)

  20. Multi-isotope (carbon and chlorine) analysis for fingerprinting and site characterization at a fractured bedrock aquifer contaminated by chlorinated ethenes

    International Nuclear Information System (INIS)

    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 δ13C 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 δ37Cl values for TCE in the contaminant sources, ranging from + 0.53 to + 0.66‰. Variations of δ37Cl and δ13C 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 (13C,35Cl) survey • Innovative/new approach tested in a fractured bedrock site • Differentiation of distinct CAH sources • Biodegradation and source mixing recognition in the aquifer

  1. Structure contours of base of upper Arapahoe aquifer in "Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado." Hydrologic Atlas 742

    Science.gov (United States)

    Rafferty, Sharon

    1998-01-01

    This digital geospatial data set consists of structure contours on the base of the upper member of the Arapahoe aquifer. The U.S. Geological Survey developed this data set as part of a project described in the report,"Structure, Outcrop, and Subcrop of the Bedrock Aquifers Along the Western Margin of the Denver Basin, Colorado" (Robson and others, 1998)

  2. 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

  3. 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.

  4. Model-based clustering of hydrochemical data to demarcate natural versus human impacts on bedrock groundwater quality in rural areas, South Korea

    Science.gov (United States)

    Kim, Kyoung-Ho; Yun, Seong-Taek; Park, Seong-Sook; Joo, Yongsung; Kim, Tae-Seung

    2014-11-01

    Improved evaluation of anthropogenic contamination is required to sustainably manage groundwater resources. In this study, we investigated the hydrochemical measurements of 18 parameters from a total of 102 bedrock groundwater samples from two representative rural areas in South Korea. We used model-based clustering with a normal (Gaussian) mixture model to differentiate the contributions of natural versus anthropogenic processes to the observed groundwater quality. Water samples varied in hydrochemistry from a Ca-Na-HCO3 type to a Ca-HCO3-Cl type. The former type reflected derivation of major ions largely from water-rock interactions, while the latter type recorded varying degrees of anthropogenic contamination. Among the major dissolved ions, fluoride and nitrate were shown to be good indicators of the two types, respectively. The results of model-based clustering showed that the bivariate normal mixture model, which was based on the covariance of nitrate and fluoride, was more robust than multivariate analysis, and provided better discrimination between the anthropogenic and natural groundwater groups. Model-based clustering to measure the degree of cluster membership for each sample also showed a gradual change in groundwater chemistry due to mixing between the two water groups. This study provided an example of the successful application of model-based clustering to evaluate regional groundwater quality and demonstrated that better selection of the dimensional structure (i.e., selection of optimal variables and number of clusters) based on hydrochemistry was crucial in obtaining reasonable clustering results.

  5. Heavy minerals and garnet geochemistry of stream sediments and bedrocks from the Almklovdalen area, Western Gneiss Region, SW Norway: Implications for provenance analysis

    Science.gov (United States)

    Krippner, Anne; Meinhold, Guido; Morton, Andrew C.; Schönig, Jan; von Eynatten, Hilmar

    2016-05-01

    Detrital heavy minerals commonly document the geological setting in the source area, hence they are widely used in sedimentary provenance analysis. In heavy mineral studies, the 63-125 and 63-250 μm grain size fractions are most commonly used. Heavy mineral data and garnet geochemistry of stream sediments and bedrocks from the catchment area draining the Almklovdalen peridotite massif in SW Norway reveal that a wider grain size spectrum needs to be considered to avoid misleading interpretations. The Almklovdalen peridotite massif consists mainly of dunite and harzburgite, as testified by the heavy mineral suite. At the outlet of the main river, the heavy mineral spectrum is very monotonous due to dilution by a strong influx of olivine. Heavy minerals like apatite and epidote characterising the host gneisses have almost disappeared. MgO-rich almandine garnets are more frequent in the coarser grain size fractions, whereas MnO-rich almandine garnets are more frequent in the finer grain size fractions. Garnets with pyrope content exceeding 50% are only found in the 500-1000 μm grain size fraction. Therefore, the sample location and the selected grain size fraction are of paramount importance when dealing with heavy minerals and mineral geochemical data; otherwise, provenance-sensitive information may be missed.

  6. Structure contours of top of Laramie-Fox Hills aquifer in "Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of Denver Basin, Colorado." Hydrologic Atlas 742

    Science.gov (United States)

    Rafferty, Sharon

    1998-01-01

    This digital geospatial data set consists of structure contours of the top of the Laramie-Fox Hills aquifer along the Front Range of Colorado. The U.S. Geological Survey developed this data set as part of a project described in the report, "Structure, Outcrop, and Subcrop of the Bedrock Aquifers Along the Western Margin of the Denver Basin, Colorado" (Robson and others, 1998).

  7. New constraints on paleo-denudation history of the Ladakh Batholith - applying bedrock and detrital apatite (U-Th-Sm)/He thermochronology

    Science.gov (United States)

    Sahragard Sohi, Mohammad; Rosenkranz, Ruben; Spiegel, Cornelia

    2015-04-01

    The Ladakh Batholith is part of the Transhimalayan Plutonic Belt and records the early exhumation history of the Himalayan orogen. The evolution of the Ladakh Batholith is complex and was controversially discussed in the literature (see Kirstein, 2011 for details). Recent data by Kirstein et al. (2006 & 2009) suggest a trend of exhumation rates across the batholith, with earlier exhumation along its southern margin and later exhumation in the north. Apart from methodological purpose aimed at refining the apatite (U-Th-Sm)/He technique, the goal of our study is to investigate the earliest denudation history of the Ladakh Pluton and thereby that of the Himalayan orogen, using apatite (U-Th-Sm)/He thermochronology (i) applied to bedrocks from the southern margin of the batholith, and (ii) to sediments from the adjacent Upper Indian Group sediments such as Nurla, Choksti, and Nimu Formations with Early Eocene to Late Miocene in age (Henderson et al., 2010). These sediments are thought to be sourced from the Ladakh Batholith (Henderson et al., 2011). Apatite (U-Th-Sm)/He dating is sensitive to temperatures between ~85 and 40°C and thus to geodynamic movements of the upper ~1.5 to 3 km of the earth's crust. While thermochronology data from present-day bedrock exposures provides denudation rates integrated over the time between cooling age and the present, the earlier denudation history is eroded away from the present exposures and stored in the syn-tectonic sediments. Thus, dating sediments of the Indian Group will yield the paleo-denudation history of the (southern) Ladakh area, including changes of denudation rates back through time. This will reveal new insights into the relation between tectonics, climate, and erosion. References Henderson, A. L., Y. Najman, R. Parrish, M. BouDagher - Fadel, D. Barford, E. Garzanti, and S. Andò (2010), Geology of the Cenozoic Indus Basin sedimentary rocks: Paleoenvironmental interpretation of sedimentation from the western Himalaya

  8. 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

  9. 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

  10. Geophysical and hydrogeological characterisation of the impacts of on-site wastewater treatment discharge to groundwater in a poorly productive bedrock aquifer

    International Nuclear Information System (INIS)

    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

  11. Geophysical and hydrogeological characterisation of the impacts of on-site wastewater treatment discharge to groundwater in a poorly productive bedrock aquifer.

    Science.gov (United States)

    Donohue, Shane; McCarthy, Valerie; Rafferty, Patrick; Orr, Alison; Flynn, Raymond

    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 100m 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

  12. Experiment on crack strain of rubber aggregate concrete restrained by bedrock%岩基约束橡胶集料混凝土开裂应变试验

    Institute of Scientific and Technical Information of China (English)

    王可良; 隋同波; 许尚杰; 刘玲

    2013-01-01

    Prevention of bedrock concrete cracking can improve the durability and operation safety of hydraulic structures.In this work,the cracking mechanism and restrained strain of rubber aggregate motar were studied through an experiment of restrained loop with resistance strain gauges,scanning electron microscrope and mercury porosimeter.The strain gauges were buried into bedrock concrete for measurement of restrained strain of rubber aggregate concrete.The results reveal that the rubber aggregate material under stressing causes a change in the shape of pores in the cement paste matrix and part of its stress is released.In the condition of ordinary motar cracking,this material develops curing strain and larger restrained strain,so the concrete does not crack.At the ages of 45d and 90d,the restrained strain in ordinary bedrock concrete is reduced quickly and its cracks start developing.Thus,rubber aggregate can improve the performances of bedrock concrete against cracking.This study provides an effective technical measure for prevention of bedrock concrete cracking.%解决岩基混凝土开裂有利于提高水工建筑物的耐久性和安全运行.采用约束圆环试验、电阻应变仪、电子扫描电镜和压汞试验,分析了橡胶集料砂浆约束开裂应变及其作用机理.在岩基混凝土内埋设应变计,观测橡胶集料混凝土的约束应变.结果表明:橡胶集料在应力作用下,改变了水泥石中孔的形态,缓冲部分应力,普通砂浆开裂时,橡胶集料开始表现硬化应变.在45d和90d龄期时,岩基普通混凝土应变急剧降低,混凝土出现开裂.岩基橡胶集料混凝土约束应变大,混凝土无开裂.橡胶集料有利于改善岩基混凝土的抗裂性能,为解决岩基混凝土裂缝提供一种新的技术措施.

  13. Geology, Bedrock, Surficial and geologic hazard map of the NPS Blue Ridge Parkway corridor. Majority of central and southern segments completed with entire project completed by October 2008., Published in 2004, 1:12000 (1in=1000ft) scale, NC DENR / Div. of Land Resources / Geological Survey Section.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Geology, Bedrock dataset, published at 1:12000 (1in=1000ft) scale, was produced all or in part from Field Survey/GPS information as of 2004. It is described as...

  14. Unpublished Digital Bedrock Geology Map of Herbert Hoover National Historic Site and Vicinity, Iowa (NPS, GRD, GRI, HEHO, HHBR digital map) adapted from Iowa Geological Survey Open-File Report Maps by Witzke et. al. (2010) and Witzke and Anderson (2008)

    Data.gov (United States)

    National Park Service, Department of the Interior — The Unpublished Digital Bedrock Geology Map of Herbert Hoover National Historic Site and Vicinity, Iowa is composed of GIS data layers complete with ArcMap 9.3...

  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. Kinematics of steep bedrock permafrost

    OpenAIRE

    Hasler, Andreas; Gruber, Stephan; Beutel, Jan

    2012-01-01

    The mechanisms that control climate-dependent rockfall from permafrost mountain slopes are currently poorly understood. In this study, we present the results of an extensive rock slope monitoring campaign at the Matterhorn (Switzerland) with a wireless sensor network. A negative dependency of cleft expansion relative to temperature was observed at all clefts for the dominant part of the year. At many clefts this process is interrupted by a period with increased opening and shearing activity i...

  17. Taste: The Bedrock of Flavor

    OpenAIRE

    Beauchamp, Gary K.

    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...

  18. 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 deforma

  19. Site investigation SFR. Bedrock geology

    International Nuclear Information System (INIS)

    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

  20. 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)

    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

  1. 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

  2. Factors Affecting Specific-Capacity Tests and their Application--A Study of Six Low-Yielding Wells in Fractured-Bedrock Aquifers in Pennsylvania

    Science.gov (United States)

    Risser, Dennis W.

    2010-01-01

    This report by the U.S. Geological Survey, prepared in cooperation with the Pennsylvania Department of Environmental Protection, Bureau of Mining and Reclamation, evaluates factors affecting the application of specific-capacity tests in six low-yielding water wells in areas of coal mining or quarrying in Pennsylvania. Factors such as pumping rate, duration of pumping, aquifer properties, wellbore storage, and turbulent flow were assessed by theoretical analysis and by completing multiple well tests, selected to be representative of low-yielding household-supply wells in areas of active coal mining or quarrying. All six wells were completed in fractured-bedrock aquifers--five in coal-bearing shale, siltstone, sandstone, limestone, and coal of Pennsylvanian and Permian age and one in limestone of Cambrian age. The wells were pumped 24 times during 2007-09 at rates from 0.57 to 14 gallons per minute during tests lasting from 22 to 240 minutes. Geophysical logging and video surveys also were completed to determine the depth, casing length, and location of water-yielding zones in each of the test wells, and seasonal water-level changes were measured during 2007-09 by continuous monitoring at each well. The tests indicated that specific-capacity values were reproducible within about ? 20 percent if the tests were completed at the same pumping rate and duration. A change in pumping duration, pumping rate, or saturated aquifer thickness can have a substantial effect on the comparability of repeated tests. The largest effect was caused by a change in aquifer thickness in well YO 1222 causing specific capacity from repeated tests to vary by a factor of about 50. An increase in the duration of pumping from 60 to 180 minutes caused as much as a 62 percent decrease in specific capacity. The effect of differing pumping rates on specific capacity depends on whether or not the larger rate causes the water level in the well to fall below a major water-yielding zone; when this

  3. 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

  4. 基岩脱空条件下仰拱结构疲劳寿命的计算方法%Fatigue life calculation method of tunnel base structure under the conditions of bedrock void

    Institute of Scientific and Technical Information of China (English)

    刘宁; 彭立敏; 施成华

    2016-01-01

    Due to tunneling construction disturbance and long-term cyclic heavy haul train loading,the void of surrounding rock may appear at the bottom of tunnel.The conditions of bedrock void affect the fatigue life of tun-nel base structure.In the paper,the softening of surrounding rock at the bottom of heavy-haul tunnel was intro-duced into the fatigue life analysis and dynamic response of the base structure.The analyses were carried out by using the finite element method.Based on the vertical load induced by train vibration and the linear cumulative damage theory,the fatigue life prediction of tunnel base structure was established to study the influence of the bed situation on the force status of railway tunnel base structure.The results show that the maximum value of ten-sile stress emerges at the center of the invert,so does the compressive stress at the junction of the sidewall and invert.The distribution of dynamic response of the base structure is similar under different conditions of bedrock void.As the void extent increases,the tensile stress and pressure stress amplitude of the base structure increase, and the fatigue life of the base structure is also reduced greatly.%由于隧道施工扰动及重载列车长期循环荷载作用下,隧道底部围岩出现局部基岩脱空现象。基岩脱空引起拱底围压的差异性分布,进而关系到隧道仰拱结构的疲劳寿命。通过引入重载列车隧道结构振动理论和Miner线性累积损伤理论,建立考虑基岩脱空条件下仰拱结构疲劳寿命的预测方法,研究基岩脱空条件下列车荷载对铁路隧道底部结构疲劳寿命的影响。计算结果表明:在隧道底部基岩脱空条件下,隧底结构仰拱中心处出现拉应力最大值,仰拱与边墙连接处出现压应力最大值,仰拱结构动应力响应分布规律相似。随着脱空变量的增大,隧底结构各部位动拉应力和动压应力增幅较大,仰拱结构疲劳寿命明显减小。

  5. Experimental research on seismic failure mode and supporting for slope of bedrock and overburden layer%地震力作用下基覆边坡模型试验研究

    Institute of Scientific and Technical Information of China (English)

    赵安平; 冯春; 李世海; 艾畅; 刘洋

    2012-01-01

    以汶川灾区实地考察资料为背景,选择宇宫庙滑坡为参照,制作了模型试验台,在量纲分析的基础上,对主要参数做了相似理论研究,并采用水下爆炸的方式来模拟地震波(近场)进行了大量模型试验.结果表明:基覆边坡在地震力作用下的破坏模式是浅表层张拉而导致表层松散体流坍,且地震加速度随着药量(地震烈度)的增加而呈递增趋势,重力墙、桩板墙等支挡结构对于基覆边坡的作用明显.其结论将为铁路、公路沿线的高陡边坡分析和研究提供一定的依据.%According to the site investigation of Wenchuan disaster area's statistics data as the background, the experiment model is made selecting Yugongmiao slope as the reference. The similarities of main parameters are analyzed based on dimensional analysis. The underwater blasting is used to simulate seismic wave (near-field), and a large number of model tests are conducted. The results show that the failure model of bedrock and overburden layer slope under seismic loading is surface loose media flowing caused by the tension of superficial layer, and with the increase of explosives (seismic intensity), seismic accelerations increase. It is very useful to design of gravity retaining wall and pile-wall structures. These conclusions can provide some bases for analysis and research of high-steep slopes along railways and highways.

  6. Three-dimensional numerical simulation of curtain grouting in the dam bedrock based on binghamian grouts%大坝基岩帷幕宾汉姆浆液灌浆的三维数值模拟

    Institute of Scientific and Technical Information of China (English)

    邓韶辉; 王晓玲; 敖雪菲; 任炳昱; 李瑞金

    2016-01-01

    Because of the grouting engineering of masking and the complexity of geological conditions, how to accurately determine the diffusion regularity of grout under complicated geological conditions is the key and difficult point of grouting numerical simulation analysis. Binghamian grouts two-phase flow characteris⁃tics in the process of grout diffusion and complex geological conditions of dam bedrock is not considered in the present numerical simulation research of grouting in the hydraulic engineering. These research objects mainly focus on a single fracture or a single grout hole, while the simulation of grout front has not in⁃volved. Aim at the above-mentioned problems,a three-dimensional refined geological information model,in⁃cluded different formations,unfavorable geological body, curtains, grouting holes, was firstly established in this paper. Then, coupled with the volume of fluid (VOF) method in the CFD commercial software STAR-CCM+, a three-dimensional grouting mathematical model of Binghamian grouts air-grout two-phase flow was developed to achieve the numerical simulation of the multiple holes and sequencing grouting in the dam bedrock,also analyzing the grout diffusion rule and curtain lap after grouting. Finally,a hydropow⁃er station of bedrock curtain grouting process was taken as a case. The results show that the grout diffu⁃sion radius increases with time in a certain time range,but its rate of change shows a decline trend. After grouting completion of each sequence hole,grout front laps well. Furthermore,comparing the simulation val⁃ue with the actual measuring value of the grouting quantity and time, the average errors were 9.08% and 6.32% respectively,which verified the reliability of the method.%由于灌浆工程的掩蔽性和地质条件的复杂性,如何准确地确定复杂地质条件下浆液的扩散规律是灌浆数值模拟分析的关键及难点。目前,在水利工程中灌浆数值模拟的

  7. Chemistry of deep groundwaters from granitic bedrock

    International Nuclear Information System (INIS)

    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)+ -Ca2(sup)+ -HCO3(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 (180 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)

  8. Bedrock Geology of the Thiel Mountains, Antarctica.

    Science.gov (United States)

    Ford, A B; Aaron, J M

    1962-09-01

    Cordierite-bearing, hyper-sthene-quartz monzonite porphyry, the most widespread rock unit, is intruded by biotite granite and porphyritic biotite granite. Sedimentary and metasedimentary rocks, mainly quartzites and argillites, have been metamorphosed locally to hornfels and have been involved in high-angle faulting. Shear zones are common in the plutonic rocks. PMID:17732193

  9. 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

  10. Hydraulic Characteristics of Bedrock Constrictions and Evaluation of One- and Two-Dimensional Models of Flood Flow on the Big Lost River at the Idaho National Engineering and Environmental Laboratory, Idaho

    Science.gov (United States)

    Berenbrock, Charles; Rousseau, Joseph P.; Twining, Brian V.

    2007-01-01

    A 1.9-mile reach of the Big Lost River, between the Idaho National Engineering and Environmental Laboratory (INEEL) diversion dam and the Pioneer diversion structures, was investigated to evaluate the effects of streambed erosion and bedrock constrictions on model predictions of water-surface elevations. Two one-dimensional (1-D) models, a fixed-bed surface-water flow model (HEC-RAS) and a movable-bed surface-water flow and sediment-transport model (HEC-6), were used to evaluate these effects. The results of these models were compared to the results of a two-dimensional (2-D) fixed-bed model [Transient Inundation 2-Dimensional (TRIM2D)] that had previously been used to predict water-surface elevations for peak flows with sufficient stage and stream power to erode floodplain terrain features (Holocene inset terraces referred to as BLR#6 and BLR#8) dated at 300 to 500 years old, and an unmodified Pleistocene surface (referred to as the saddle area) dated at 10,000 years old; and to extend the period of record at the Big Lost River streamflow-gaging station near Arco for flood-frequency analyses. The extended record was used to estimate the magnitude of the 100-year flood and the magnitude of floods with return periods as long as 10,000 years. In most cases, the fixed-bed TRIM2D model simulated higher water-surface elevations, shallower flow depths, higher flow velocities, and higher stream powers than the fixed-bed HEC-RAS and movable-bed HEC-6 models for the same peak flows. The HEC-RAS model required flow increases of 83 percent [100 to 183 cubic meters per second (m3/s)], and 45 percent (100 to 145 m3/s) to match TRIM2D simulations of water-surface elevations at two paleoindicator sites that were used to determine peak flows (100 m3/s) with an estimated return period of 300 to 500 years; and an increase of 13 percent (150 to 169 m3/s) to match TRIM2D water-surface elevations at the saddle area that was used to establish the peak flow (150 m3/s) of a paleoflood

  11. 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

  12. 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)

  13. 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

    2015-01-01

    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.

  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. [GTK 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. Modelling of bedrock and groundwater flow for site evaluation

    International Nuclear Information System (INIS)

    Site for final disposal of spent nuclear fuel in Finland will be selected by the end of the year 2000. TVO is responsible for site selection program. In 1987 five areas were selected for preliminary site characterization. Areas comprise Finnish Precambrian crystalline rock types. Typical extent of an area under investigation is 5-8 square-km. In 1992 will be decided which 2 or 3 areas will be characterized in detail during 1993-2000. The emphasis of site investigation is put on the identification and analysis of hydraulically conductive zones and fracturing. Three-dimensional groundwater modelling has been a tool to evaluate suitability of the area for final disposal from the safety point of view. Attempts are made to increase the degree of reality in groundwater modelling. Computer code used: FEFLOW. 6 figs., 2 tabs

  16. Glacial flutings in bedrock, an observation in East Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby

    1978-01-01

    Large scale glacial flutings cover an area of 4 x 1.5 km on the northern shore of Harefjord in the interior Scoresby Sund fjord complex. The flutings are modelled in coarse sandstone and conglomerates, a few small features are probably composed of till. The ridges measure up to' 2000 m in length ...... 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. Chemical durability of copper canisters under crystalline bedrock repository conditions

    International Nuclear Information System (INIS)

    In the Swedish waste management program, the copper canister is expected to provide containment of the radionuclides for a very long time, perhaps millions of years. The purpose of the present paper, is to analyze prerequisites for assessments of corrosion lifetimes for copper canisters. The analysis is based on compilations of literature from the following areas: chemical literature on copper and copper corrosion, mineralogical literature with emphasis on the stability of copper in near surface environments, and chemical and mineralogical literature with emphasis on the stabilities and thermodynamics of species and phases that may exist in a repository environment. Three main types of situations are identified: (1) under oxidizing and low chloride conditions, passivating oxide type of layers may form on the copper surface; (2) under oxidizing and high chloride conditions, the species formed may all be dissolved; and (3) under reducing conditions, non-passivating sulfide type layer may form on the copper surface. Considerable variability and uncertainty exists regarding the chemical environment for the canister, especially in certain scenarios. Thus, the mechanisms for corrosion can be expected to differ greatly for different situations. The lifetime of a thick-walled copper canister subjected to general corrosion appears to be long for most reasonable chemistries. (It is assumed that the canister has no defects from manufacturing and that the bentonite buffer is intact). Localized corrosion may appear for types (1) and (3) above but the mechanisms are widely different in character. The penetration caused by localized corrosion can be expected to be very sensitive to details in the chemistry

  18. Intrinsic bioremediation of diesel-contaminated cold groundwater in bedrock

    International Nuclear Information System (INIS)

    Natural attenuation refers to the natural process by which contaminants in groundwater or soil are reduced through a combination of physico-chemical processes and biodegradation by indigenous organisms. The physico chemical processes include advection, dilution, dispersion, sorption, volatilization and abiotic transformation. This study evaluated the historical contaminant and geochemical evidence of natural attenuation at a well site where groundwater had been contaminated by a diesel fuel leak in 1982. In particular, evidence of intrinsic bioremediation was evaluated. Evidence of microbial activity was determined by most probably number (MPN) and commercial biological activity reaction tests. Groundwater samples from the site were incubated in a laboratory under aerobic and anaerobic conditions with electron acceptor and nutrient amendment to assess microbial activity. Mineralization of carbon 14-dodecane was measured to determine aerobic biodegradation rates. Anaerobic biodegradation rates were calculated from the depletion of total extractable hydrocarbon over 717 days. Nutrient addition increased the anaerobic first-order biodegradation rate from 0.0005 to 0.0016 per day. It was suggested controlled nutrient addition can improve the current slow rates of intrinsic bioremediation. 33 refs., 9 tabs., 5 figs

  19. Reinjection Tests in bedrock Geothermal Reservoir of Tianjin

    Institute of Scientific and Technical Information of China (English)

    朱家玲; 王坤

    2004-01-01

    By the end of 2002, there are about 219 production wells (including 12 reinjection wells) in Tianjin. The annual production rate is 1.5×107 m3 and the reinjection rate is 1.66×106 m3. The main side effect anticipated from reinjection is the cooling of the reservoir. It is necessary to estimate the thermal breakthrough time in different distances between injection-production wells. This paper describes the 2-D mass and heat transfer in the heterogeneous fractured rocks. The equations that arise for each grid block must be linearized. The main reinjection model is simulated by a program of the TOUGH2 to analyze the change of the temperature field and predict the pressure and heat break-through. The tracer test is very important for understanding the transportation pathway and transport channel/space in the doublet system, and estimating the possible cooling resulted from the injection processes.

  20. Significant differences in late Quaternary bedrock erosion and transport

    DEFF Research Database (Denmark)

    Andrews, John; Bjørk, Anders Anker; Eberl, Dennis;

    2015-01-01

    We use quantitative X-ray diffraction to determine the mineralogy of late Quaternary marine sediments from the West and East Greenland shelves offshore from early Tertiary basalt outcrops. Despite the similar basalt outcrop area (60 000–70 000 km2), there are significant differences between East...... and West Greenland sediments in the fraction of minerals (e.g. pyroxene) sourced from the basalt outcrops. We demonstrate the differences in the mineralogy between East and West Greenland marine sediments on three scales: (1) modern day, (2) late Quaternary inputs and (3) detailed down-core variations...

  1. Analysis on Numerical Simulation of Mine Strata Behavior Law in Shallow Depth Seam with Bulk Overbarden Soil and Thin Bedrock Overburden%松散表土薄基岩浅埋煤层矿压显现规律数值分析

    Institute of Scientific and Technical Information of China (English)

    田建胜; 王建利; 王水利; 方新秋; 高海亮

    2011-01-01

    为了分析松散表土薄基岩浅埋煤层首采工作面上覆岩层的运动规律,尤其是顶板初次来压和周期来压步距,运用UDEC软件对神木汇森凉水井煤矿首采面上覆岩层矿压显现规律进行了数值模拟,在此基础上进行了现场实测。结果表明,首采面初次来压步距的计算值为40.0 m,实测值32.8 m;周期来压步距的计算值为20 m,实测周期来压步距为16.5~22.0 m,平均为19.5 m;强制放顶距为20 m时能减小初次来压强度;强制放顶能有效地削弱和减小顶板初次来压的强度和规模,保证强制放顶效果的关键是提高强制放顶爆破作业的质量。%In order to analyze the movement law of the strata above the first coal mining face in the seam with a shallow depth of bulk overburden soil and thin base bedrock,especially to analyze the roof initial pressurized and periodical pressurized distance to the UDEC software was applied to numerically simulate the pressure behavior law of the roof strata above the first coal mining face in Shenmu Huisen Liangshuijing Mine.Based on the circumstance,a site measurement was conducted.The results showed that the calculated value of the roof initial pressurized distance in the first coal mining face was about 40.0 m and the site measured distance was 32.8 m.The calculated value of the roof periodical pressurized distance was about 20 m,the site measured roof periodical pressurized distance was about 16.5~22.0 m and the average distance was 19.5 m.The forced roof caving distance of 20 m could eliminate the roof initial pressured.The forced roof caving could be effectively to relax and reduce the roof initial pressurized strength and scale.The key to ensure the forced roof caving results is to improve the blasting operation quality of the roof forced caving.

  2. STEAM INJECTION REMEDIATION IN FRACTURED BEDROCK AT LORING AIR FORCE BASE

    Science.gov (United States)

    Contaminated groundwater occurs at many Superfund, RCRA, and Brownfields sites. Chlorinated solvents which can form a dense nonaqueous phase (DNAPL) when released to the subsurface can pose an extreme challenge for remediation, as DNAPLs are often difficult to locate and even ha...

  3. Deformation and stabilisation mechanisms of slow rock slides in crystalline bedrock

    Science.gov (United States)

    Zangerl, C.; Prager, C.

    2009-04-01

    Deep-seated rock slides are slope instabilities which are characterised by deformation along one or several shear zones where most of the measured total slope displacement localizes. Generally, a high danger potential is given when rock slides fail in a rapid manner characterised by very high sliding velocities and/or when they develop into long run-out rock avalanches. However several field surveys and deformation monitoring data show that numerous deep-seated rock slides do not fail in a high velocity regime. In fact, many slides creep downwards at rates of some centimetres per year or even less and do not show any evidence for non-reversible acceleration in the past or in the future. Furthermore some of these slope instabilities are actually inactive (dormant) or have even reached a stabilised final state. Deformation monitoring on active rock slides show that acceleration phases characterised by velocities up to meters per day can occur. The trigger for these phases can be manifold and include heavy rainfall, snow melt, water level fluctuations of reservoirs at the slope foot, changes in the slope's equilibrium state due to antecedent slow creeping processes, changes in the material behaviour within the sliding zone, erosion along the foot of the slope, etc. Whereas the role of these triggers in promoting phases of acceleration are generally understood, the same can not be said regarding the kinematics and dynamic processes/mechanisms by which rock slide masses re-stabilise once the trigger impetus has been removed. In the context of this study the term "stabilisation" is used for rock slides which decelerate from high velocities to slow base activities or even stop moving after a certain amount of displacement. Given that reliable rock slide forecasts require the fundamental understanding of possible slope stabilisation mechanisms this study focuses on field-based and numerically obtained key-properties which influence the long-term slope deformation behaviour. On a regional scale several valleys located in amphibolites, ortho- and paragneisses of the Ötztal-Stubai crystalline basement (i.e. Kaunertal, Pitztal, Ötztal, Lüsenstal, all located in North Tyrol, Austria) were investigated. Therefore geological and morphological basis data were compiled and re-evaluated, remote sensing methods (i.e. airborne laser scanning terrain models and orthofotos) applied and field mapping campaigns performed. On a local scale several rock slides were investigated and analysed in high detail with regard to their lithological and structural inventory, geometry of sliding masses and -zones, failure mechanisms, kinematics and temporal deformation characteristics. Field data clearly show that competent rock masses, e.g. orthogneisses and amphibolites, are affected by rapid failure events and therefore are characterised by "brittle" rock mass behaviour. In contrast, the majority of the slowly moving and "self-stabilising" rock slides are located totally or partly in mica-rich incompetent crystalline rock masses, e.g. paragneisses and micaschists, and are characterised by moderately dipping sliding zones. Apart from a causal lithological influence, numerous field observations demonstrate a major influence of pre-existing geological structures on the formation and deformation behaviour of these rock slides. The nature of rock slides implies that the temporal deformation behaviour is primarily dominated by two key-features of the sliding zone i.e. the mechanical properties (shear strain strengthening or weakening) and the effective in-situ stresses. The in-situ stresses along a sliding zone are influenced by the geometry of both the sliding mass and sliding zone, the internal deformation of the sliding mass and the pore pressures. All these properties can vary during progressive shear displacements. Especially large shear displacements in the range of tens to hundreds of metres along a distinct sliding zone can cause significant in-situ stress changes which in turn may influence the slope deformation behaviour and stabilisation mechanisms. In order to study these processes for selected case studies in paragneissic rock masses the impact of the sliding mass geometry and sliding zone shape on the in-situ stresses has been investigated by applying the discrete element method. This numerical approach enables the simulation of large shear displacements and complex block assembly interactions. Results show that slope stabilisation can be achieved when the dip angle of the sliding zone flattens downslope. In this case and after a certain amount of displacement the lower part of the rock slide mass reaches stable slope conditions (shear strength of the sliding zone material exceeds the shear stress acting on the sliding zone) and acts as a resisting mass for the still unstable upper part of the slope. Furthermore numerical models show that secondary slides at the lower part of the slope have a similar effect. In both case cases the observed slope stabilisation can be clearly attributed to the formation of natural buttressing masses at the toe.

  4. Uranium and radon in wells drilled into bedrock in Southern Finland

    International Nuclear Information System (INIS)

    More than 1000 samples of groundwater were taken from drilled wells in Southern Finland in 1982-1986 and submitted to chemical analyses that included the determination of uranium and radon abundances in the water. The waters were divided into eight groups by dominant rock type to establish the influence of the geological environment of the water. The median radon abundance for the total data on the drilled wells in southern Finland was 210 Bq/l, and that of uranium 5 ppb. The maximum uranium abundance was 20 000 ppb and that of radon about 50 000 Bq/l

  5. A Field Test Of The Influence Of Grain Size In Determining Bedrock River Channel Slope

    OpenAIRE

    Klier, Rachael Emily

    2014-01-01

    Interpreting spatial patterns in rates of fluvial incision from river channel elevation long profile data requires an assumption that tectonic uplift rate governs river channel slope. However, application of the most mechanistically explicit description of river incision [Sklar and Dietrich,2004] suggests that sediment flux and sediment grain size, not rock uplift rate, control river channel slopes in many settings. Because it is usually difficult to independently constrain sediment supply,...

  6. How to find the sedimentary archive of fluvial pollution in a bedrock-confined river reach

    Science.gov (United States)

    Elznicova, Jitka; Matys Grygar, Tomas; Kiss, Timea; Lelkova, Tereza; Balogh, Marton; Sikora, Martin

    2016-04-01

    The Ohre River springs in the Eastern Germany and it is a tributary of the Labe (Elbe) River in Northwest Bohemia. The river received pollution from several sources during the last five centuries. Most of the pollution sources located along the upper and middle reaches, where the depositional and erosional pattern of the river is highly variable. The upper part of the catchment consists of mainly felsic rocks and the river has a broad floodplain. The middle reach and its right-bank tributaries are deeply incised into the Doupovske Hory Mts., which consists of mafic volcanic rocks; whereas the left-bank tributaries are incised into intrusive and metamorphic rocks of the Krusne Hory Mts. (Ore mountains) with several local ore mines (Ag, Pb and U) in particular in around Olovi and Jachymov. Due to the geologic and geomorphologic complexity, deposition of historical sediments in the middle reach has been spatially limited and uneven, and anomalous background concentrations of risk elements are expected. As a consequence, in the middle reach of the Ohre River it is difficult to find a useful sedimentary archive of historical pollution, though it is desired for two main reasons: (1) to decipher the undocumented and poorly described pollution history from the Krusne Hory Mts. and (2) to better understand the retention of pollutants in the transport zones of a confined river system. Based on historical maps we identified a side-bar (35x320 m) in the middle reach of the river near Straz on Ohre and aimed to describe its formation, its recent erosion/deposition history and to evaluate its sedimentary archive value. In the first half of the 19th century it was an island separated from the valley edge by a side channel. Since then there has been no apparent lateral accretion of the bar (its shape has not been changed), but the upstream part of the side channel aggraded by a sediment plug. We evaluated the current bar topography and geomorphology by a detailed field survey, dated the sediments by dendrology and OSL dating, and performed in situ XRF analysis of sediment cores. The data show that the downstream head of the bar is the oldest and most of fine sediments (mostly sand, minor silt) of the bar material have been historically polluted by Pb mining. The sedimentary sequences, most valuable for reconstruction of recent pollution, were found in the side channel where the fill the representing the last ca 150 years pollution history (Hg and U). The body of the bar has been formed earlier. According to our hypothesis the bar originated as a direct consequence of historical mining in the nearby Jachymov Ore Region. The use of lateral fluvial deposits as a sedimentary archive definitely requires intensive application of fluvial geomorphology. Vice versa, pollution patterns will allow delineating areas, in particular the bar bank and inlet to the side channel, where intensive reworking (erosion/redeposition) occurred as documented by the microtopography and woody debris.

  7. SRS BEDROCK PROBABILISTIC SEISMIC HAZARD ANALYSIS (PSHA) DESIGN BASIS JUSTIFICATION (U)

    Energy Technology Data Exchange (ETDEWEB)

    (NOEMAIL), R

    2005-12-14

    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.

  8. Characterization of humic substances from deep groundwaters in granitic bedrock in Sweden

    International Nuclear Information System (INIS)

    Humic substances were isolated from deep groundwaters sampled at depths between 100 and 800 m at Finnsjoen, Fjaellveden, Forsmark, Gidea, Lansjaerv, Stripa and Aespoe. The humic fraction, which largely consisted of fulvic acid in all the samples, was characterized with respect to elemental composition, molecular weight, acid capacity (COOH and OH) as well as age (14C). The differences in composition and capacity between old (1270-9675 y) and fresh (reference fulvic acid from surface water, Bersbo) were minor. (orig.)

  9. Bedrock Kd data and uncertainty assessment for application in SR-Site geosphere transport calculations

    International Nuclear Information System (INIS)

    The safety assessment SR-Site is undertaken to assess the safety of a potential geologic repository for spent nuclear fuel at the Forsmark and Laxemar sites. The present report is one of several reports that form the data input to SR-Site and contains a compilation of recommended Kd data (i.e. linear partitioning coefficients) for safety assessment modelling of geosphere radionuclide transport. The data are derived for rock types and groundwater compositions distinctive of the site investigation areas at Forsmark and Laxemar. Data have been derived for all elements and redox states considered of importance for far-field dose estimates as described in /SKB 2010d/. The Kd data are given in the form of lognormal distributions characterised by a mean (μ) and standard deviation (σ). Upper and lower limits for the uncertainty range of the recommended data are defined by the 2.5% and 97.5% percentiles of the empirical data sets. The best estimate Kd value for use in deterministic calculations is given as the median of the Kd distribution

  10. Radon in a fractured bedrock aquifer: Relationships with rock type and distribution of parent radionuclides

    International Nuclear Information System (INIS)

    Ground-water samples collected from 35 domestic water wells in the Elk Creek drainage 30 miles southwest of Denver, Colorado, show a strong relationship between dissolved Rn-222 concentration and host-rock lithology. Wells completed in Precambrian Pikes Peak Granite (Ypp) average 11,000 pCi/L, whereas wells completed in Precambrian migmatitic rocks (Xm) average 4,000 pCi/L. Geophysical logs of three boreholes completed in the same rock type (Ypp) show significant differences in natural gamma traces and correspondingly different radon concentrations. One well shows a monotonous gamma response with depth, averaging 500 counts per second (cps); water from this well contains 5,300 pCi/L Rn-222. Water from the second well contains 11,000 pCi/L and the third well contain over 20,000 pCi/L. If Rn-222 parent radionuclides are homogeneously distributed along fracture walls, then Rn-222 concentration should decrease with an increasing water-volume-to-rock surface-area ratio. An inverse relationship between transmissivity and Rn-222 concentration is not observed for these 3 wells. The 2 wells with 5,300 pCi/L and 20,000 pCi/L Rn-222 in water have transmissivities of 26 and 75 gallons per day per foot (gpd/ft), respectively, whereas transmissivity for the well with 11,000 pCi/L is 195 gpd/ft. Single-well pumping tests on 29 other wells belie a systematic correlation between transmissivity and Rn-222 concentration, suggesting that local heterogeneous accumulations of Rn-222 parent radionuclides on fracture walls may strongly affect Rn-222 concentration in these wells

  11. Air - Ground - Bedrock Temperature Coupling, Its Monitoring at Borehole Climate Observatories

    Science.gov (United States)

    Cermák, V.

    2012-04-01

    Reconstructing ground surface temperature (GST) histories from present-day temperature-depth logs is now generally accepted as one of the independent and physically justified method to obtain information about the past climate history on the time scale of hundreds to thousands years. Any temperature change at the Earth`s surface slowly propagates downward and deeper we go farther back in time the measured temperature carries certain memory on what has happened on the surface in the past. Due to diffusive character of the process, however, the resolution quickly decreases for the remote events and the reconstructed GST at a given moment is a weighted average of temperature over a certain period of time. For better understanding of the temperature state in the subsurface T(z) logs can be suitably completed with long-run temperature-time monitoring at selected depth intervals, namely within the near-surface active layer affected by seasonal temperature variations (usually uppermost 30-40 m). In addition to GST inversions applied on deep T(z) profiles existing all over the world, several permanent borehole climate observatories were actually established in the last two decades to test the validity of the assumption that GST variations track the SAT (surface air temperature) changes as well as to study various environmental/local effects, such as the vegetation cover type/change, rain/snow precipitation, thawing/melting/freezing, etc. which controls the whole heat transfer process. Long-term monitoring of the shallow subsurface temperature field in suitably geographically located sites may additionally also help to understand the different conditions in e.g. urban vs. countryside environments and to assess the potential anthropogenic contribution to the present-day warming rate within the natural climate variability. This presentation summarizes main results obtained at the Czech borehole sites since 1992 completed with brief comparison of similar results collected elsewhere.

  12. Dating methods and geochronology of fractures and movements in bedrock: a review

    International Nuclear Information System (INIS)

    Constraining the absolute and relative ages of crustal movements is of fundamental importance in evaluating the potentials of a site as a repository for spent radioactive fuel. In this report a review summary of up to date absolute and relative dating methods is presented with specific attention to those methods most amenable for dating of fractures. A review of major fracture-and shear zones in the Swedish part of the Baltic Shield is also given. Since the shield has suffered a long and complicated history, geo-chronologists are faced with the problem of reactivated zones when attempting to date these. It is important to get structural control in order to make the choice of dating method since different methods may give answer to completely different questions. An integration of all geological background data is necessary in order to make the proper chose to fit the raised question

  13. An Analysis of Consolidation Grouting Effect of Bedrock Based on its Acoustic Velocity Increase

    Science.gov (United States)

    Chen, Ming; Lu, Wen-bo; Zhang, Wen-ju; Yan, Peng; Zhou, Chuang-bing

    2015-05-01

    Acoustic velocity is an important parameter to evaluate the mechanical properties of fractured rock masses. Based on the in situ acoustic velocity measurement data of ~20 hydropower stations in China, we assessed the acoustic velocity increase of rock masses as a result of consolidation grouting in different geological conditions, such as fault sites, weathered areas and excavation-induced damage zones. We established an empirical relationship between the acoustic velocity of rock masses before and after consolidation grouting, and examined the correlation between acoustic velocity and deformation modulus. A case study is presented about a foundation consolidation grouting project for an intake tower of Pubugou Hydropower Station. The results show that different types of rock masses possess distinct ranges for resultant acoustic velocity increase by consolidation grouting. Under a confidence interval of 95 %, the ranges of the increasing rate of acoustic velocity in a faulted zone, weathered zone, and excavation-induced damage zone are observed to be 12.7-43.1, 12.3-31.2, and 6.9-14.5 %, respectively. The acoustic velocity before grouting and its increasing rate can be used to predict the effectiveness of consolidation grouting.

  14. Impact of soil sorption characteristics and bedrock composition on phosphorus concentrations in two Bohemian Forest lakes

    Czech Academy of Sciences Publication Activity Database

    Kaňa, Jiří; Kopáček, Jiří

    2006-01-01

    Roč. 173, 1-4 (2006), s. 243-259. ISSN 0049-6979 R&D Projects: GA ČR(CZ) GA206/03/1583; GA AV ČR(CZ) 1QS600170504 Grant ostatní: EC(XE) GOCE-CT-2003-505540; MSM(CZ) 6007665801 Institutional research plan: CEZ:AV0Z60170517 Keywords : acidification * aluminium * forest soils Subject RIV: DJ - Water Pollution ; Quality Impact factor: 1.205, year: 2006

  15. Oskarshamn site investigation. Programme for further investigations of bedrock, soil, water and environment in Laxemar subarea

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-03-15

    SKB (the Swedish Nuclear Fuel and Waste Management Co), has been conducting a site investigation at Simpevarp and Laxemar in Oskarshamn for siting of a final repository for spent nuclear fuel. An equivalent investigation is being conducted in Forsmark in Ohmmeter's. The initial part of the site investigations had been completed for the both of the subareas Simpevarp and Laxemar in the autumn of 2004. Based on the results of these investigations, SKB preliminarily prioritized the Laxemar subarea for further investigations. A programme was presented for the first stage of the complete site investigation in the Laxemar subarea, along with the main features of the remainder of the site investigation. The programme included investigations up until the summer of 2005 and was particularly aimed at obtaining answers to several vital questions so that the subsequent investigations could be focused on the rock areas judged to be most suitable for a final repository. These investigations have now been completed. This report presents the programme for the remainder of the site investigation. The points of departure are the general goals for the Deep Repository Project during the site investigation phase, analyses and evaluations of data from completed investigations, and the needs for additional data to be able to evaluate the site as a siting alternative for the final repository. The account mainly covers the investigations on the site. All other work - analyses, site descriptive modelling, facility design, safety assessments and studies and assessments of consequences for the environment, human health and society - are only mentioned to the extent necessary in order to place the investigations in their context. The direction of the site investigation in Oskarshamn and the investigation programme presented in this report is based on SKB's preliminary decision to prioritize the Laxemar subarea for further investigations. A final decision on the direction of the site investigation in Oskarshamn is planned to be made in the spring of 2006 when preliminary safety reports have been presented for both Simpevarp and Laxemar. If the decision should then be that the Simpevarp subarea is chosen, a new investigation programme and a new timetable will be prepared. The overall goal of the site investigation phase is to obtain the permits required to site and build the final repository. The site investigations must therefore provide the data required for an evaluation of the suitability of the investigated sites for a final repository. The material must accordingly be comprehensive enough to: Show whether the selected site satisfies fundamental safety requirements. Show whether the construction-related prerequisites are met. Permit the final repository to be adapted to the conditions and features on the site. Permit an assessment of the impact of the final repository on the environment and society. Permit comparisons between the two investigated sites - Forsmark and Simpevarp/Laxemar. According to SKB's plans, the site investigation in Oskarshamn will be concluded in the late summer of 2007. Monitoring will continue after this time. A large-scale interference test, combined with tracer tests, is also planned.

  16. Drainage of the ice-dammed Lake Tinninilik, West Greenland; implication on bedrock uplift

    DEFF Research Database (Denmark)

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

    Sarqardliup sermia in West Greenland, using air- and satellite-borne laser- and radar altimetry supplemented with Landsat imagery. We combine the observations with DEMs from aerial imagery to derive lake volume changes which we compare against GPS data used to monitor crustal uplift caused by mass loss close...... to the site.Our results suggest that the previous pattern of drainage every 10th year has changed to every ~7th year, likely a result of enhanced melting over the last decade in the region. Furthermore, the lake drainage, resulting in a c. 70 m elevation change of the lake level, can occur in less...

  17. Enhanced detection of hydraulically active fractures by temperature profiling in lined heated bedrock boreholes

    Science.gov (United States)

    Pehme, P. E.; Parker, B. L.; Cherry, J. A.; Molson, J. W.; Greenhouse, J. P.

    2013-03-01

    SummaryThe effectiveness of borehole profiling using a temperature probe for identifying hydraulically active fractures in rock has improved due to the combination of two advances: improved temperature sensors, with resolution on the order of 0.001 °C, and temperature profiling within water inflated flexible impermeable liners used to temporarily seal boreholes from hydraulic cross-connection. The open-hole cross-connection effects dissipate after inflation, so that both the groundwater flow regime and the temperature distribution return to the ambient (background) condition. This paper introduces a third advancement: the use of an electrical heating cable that quickly increases the temperature of the entire static water column within the lined hole and thus places the entire borehole and its immediate vicinity into thermal disequilibrium with the broader rock mass. After heating for 4-6 h, profiling is conducted several times over a 24 h period as the temperature returns to background conditions. This procedure, referred to as the Active Line Source (ALS) method, offers two key improvements over prior methods. First, there is no depth limit for detection of fractures with flow. Second, both identification and qualitative comparison of evidence for ambient groundwater flow in fractures is improved throughout the entire test interval. The benefits of the ALS method are demonstrated by comparing results from two boreholes tested to depths of 90 and 120 m in a dolostone aquifer used for municipal water supply and in which most groundwater flow occurs in fractures. Temperature logging in the lined holes shows many fractures in the heterothermic zone both with and without heating, but only the ALS method shows many hydraulically active fractures in the deeper homothermic portion of the hole. The identification of discrete groundwater flow at many depths is supported by additional evidence concerning fracture occurrence, including continuous core visual inspection, acoustic televiewer logs, and tests for hydraulic conductivity using straddle packers as well as rock core VOC data, where available, that show deep penetration and many migration pathways. Confidence in the use of temperature profiles and the conceptual model is provided by numerical simulation and the demonstrated reproducibility of the evolution of the temperature signal measured in the lined holes with and without heating. This approach for using temperature profiling in lined holes with heating is a practical advance in fractured rock hydrogeology because the liners are readily available, the equipment needed for heating is low cost and rugged, and the time needed to obtain the profiles is not excessive for most projects.

  18. Rapid bedrock uplift in the Antarctic Peninsula explained by viscoelastic response to recent ice unloading

    DEFF Research Database (Denmark)

    Nield, Grace A.; Barletta, Valentina Roberta; Bordoni, Andrea;

    2014-01-01

    ×1017–2×1018 Pas – much lower than previously suggested for this region. Combining the LARISSA time series with the Palmer cGPS time series offers a rare opportunity to study the time-evolution of the low-viscosity solid Earth response to a well-captured ice unloading event.......Since 1995 several ice shelves in the Northern Antarctic Peninsula have collapsed and triggered ice-mass unloading, invoking a solid Earth response that has been recorded at continuous GPS (cGPS) stations. A previous attempt to model the observation of rapid uplift following the 2002 breakup...... of the Palmer cGPS station since 2002 cannot be explained by elastic deformation alone. We apply a viscoelastic model with linear Maxwell rheology to predict uplift since 1995 and test the fit to the Palmer cGPS time series, finding a well constrained upper mantle viscosity but less sensitivity to lithospheric...

  19. Quantifying irreversible movement in steep fractured bedrock permafrost at Matterhorn (CH)

    OpenAIRE

    Weber, Samuel; Beutel, Jan; Faillettaz, Jérome; Hasler, Andreas; Krautblatter, Michael; Vieli, Andreas

    2016-01-01

    Identifying precursors of gravity-driven slope instabilities in inhomogeneous fractured rock masses is a challenging task. Recent laboratory studies have brought upon an enhanced understanding of rock fatigue and fracturing in cold environments but were not successfully confirmed by field studies. In this study we monitor environmental conditions, rock temperatures and fracture dynamics at 3500 m a.s.l. on the steep, strongly fractured Hörnligrat of Matterhorn (Swiss Alps). Here...

  20. A ground water flow analysis for a nuclear waste repository excavated in bedrock

    International Nuclear Information System (INIS)

    An important part of the safety analysis of an underground disposal facility is the assessment of groundwater flow in the repository and the host rock. The groundwater flow analysis is required to produce the overall flow field as well as the flow rate through the repository, the flow paths (including lengths and transit times) into the biosphere, and the dilution factor in the geosphere

  1. Accuracy and precision of bedrock sur-face prediction using geophysics and geostatistics.

    OpenAIRE

    Örn, Henrik

    2015-01-01

    In underground construction and foundation engineering uncertainties associated with subsurface properties are inevitable to deal with. Site investigations are expensive to perform, but a limited understanding of the subsurface may result in major problems; which often lead to an unexpected increase in the overall cost of the construction project. This study aims to optimize the pre-investigation program to get as much correct information out from a limited input of resources, thus making it ...

  2. Soil-gas helium and surface-waves detection of fault zones in granitic bedrock

    Indian Academy of Sciences (India)

    G K Reddy; T Seshunarayana; Rajeev Menon; P Senthil Kumar

    2010-10-01

    Fracture and fault networks are conduits that facilitate groundwater movement in hard-rock terrains.Soil-gas helium emanometry has been utilized in Wailapally watershed,near Hyderabad in southern India,for the detection of fracture and fault zones in a granite basement terrain having a thin regolith.Based on satellite imagery and geologic mapping,three sites were selected for detailed investigation.High spatial resolution soil-gas samples were collected at every one meter at a depth of <1.5m along 100 m long profiles (3 in number).In addition,deep shear-wave images were also obtained using the multichannel analysis of surface waves.The study clearly indicates several soil-gas helium anomalies (above 200 ppb)along the pro files,where the shear-wave velocity images also show many near-surface vertical low velocity zones.We thus interpret that the soil-gas helium anomalous zones and the vertical low-velocity zones are probable traces of fault/fracture zones that could be efficient natural recharge zones and potential groundwater conduits.The result obtained from this study demonstrates the efficacy of an integrated approach of soil-gas helium and the seismic methods for mapping groundwater resource zones in granite/gneiss provinces.

  3. Groundwater flow characterization in a fractured bedrock aquifer using active DTS tests in sealed boreholes

    Science.gov (United States)

    Coleman, Thomas I.; Parker, Beth L.; Maldaner, Carlos H.; Mondanos, Michael J.

    2015-09-01

    In recent years, wireline temperature profiling methods have evolved to offer new insight into fractured rock hydrogeology. Important advances in wireline temperature logging in boreholes make use of active line source heating alone and then in combination with temporary borehole sealing with flexible impervious fabric liners to eliminate the effects of borehole cross-connection and recreate natural flow conditions. Here, a characterization technique was developed based on combining fiber optic distributed temperature sensing (DTS) with active heating within boreholes sealed with flexible borehole liners. DTS systems provide a temperature profiling method that offers significantly enhanced temporal resolution when compared with conventional wireline trolling-based techniques that obtain a temperature-depth profile every few hours. The ability to rapidly and continuously collect temperature profiles can better our understanding of transient processes, allowing for improved identification of hydraulically active fractures and determination of relative rates of groundwater flow. The advantage of a sealed borehole environment for DTS-based investigations is demonstrated through a comparison of DTS data from open and lined conditions for the same borehole. Evidence for many depth-discrete active groundwater flow features under natural gradient conditions using active DTS heat pulse testing is presented along with high resolution geologic and geophysical logging and hydraulic datasets. Implications for field implementation are discussed.

  4. Integrity of copper/steel canisters under crystalline bedrock repository conditions

    International Nuclear Information System (INIS)

    In the Swedish nuclear waste disposal programme, the need to store the spent nuclear fuel safely for very long times has prompted a strategy which includes a long life canister. Technical as well as economical considerations related to design, choice of materials and manufacturing technology have lead to the selection of a reference design to be used for the continued development work. The canisters are cylindrical with a diameter close to 1 meter and a height of about 5 meters. In order to meet the need for an appropriate combination of mechanical strength, toughness, durability and corrosion resistance, the canisters comprise an inner vessel made of steel or cast iron to cope with mechanical stresses and an outer vessel made of almost pure copper to provide corrosion resistance. The Swedish nuclear industry has recently extended its development work to full-scale tests. Such experience is needed not least for the evaluation of the long-term integrity of the canister. This work has been closely followed by the Swedish Nuclear Power Inspectorate (SKI) who have also carried out independent investigations and analyses. It should be emphasized that the findings relate to a canister which is under development and cannot, in general, be expected to be relevant for the fully developed canister. Significant results of the analyses include the identification of conceivable modes of canister failures. Such failures may be related to defects, segregation, limitations in inspectability, long term creep properties, adverse mechanical load situations, etc. It is assessed that the distribution functions of these failures might have their largest uncertainties at the tails extending to comparatively short times. Specific issues related to canister manufacture, scaling and non destructive testing which have been found to warrant further investigation are: defects in the copper ingot which may transfer to the rolled copper plate; the amount of work applied during the rolling or forging operations; grain growth in parent copper material; grain growth, formation of pores, hot tearing and segregation of matter related to welding of the copper; resolution of ultrasonic inspection especially in the presence of large grains; collapse pattern of the copper vessel onto the steel vessel; and the response of the steel vessel to different external loads including those that may appear during a glaciation or in conjunction with a faulting event. (author)

  5. 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

    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 are...... Jakobshavn Isbræ. All stations experienced uplift, but the uplift rate at Kangia North, only 5 km from the glacier front, was about 10 mm/yr larger than the rate at Ilulissat, located only 45 km further away. This suggests that most of the uplift is due to the unloading of the Earth’s surface as Jakobshavn...

  6. Oskarshamn site investigation. Programme for further investigations of bedrock, soil, water and environment in Laxemar subarea

    International Nuclear Information System (INIS)

    SKB (the Swedish Nuclear Fuel and Waste Management Co), has been conducting a site investigation at Simpevarp and Laxemar in Oskarshamn for siting of a final repository for spent nuclear fuel. An equivalent investigation is being conducted in Forsmark in Ohmmeter's. The initial part of the site investigations had been completed for the both of the subareas Simpevarp and Laxemar in the autumn of 2004. Based on the results of these investigations, SKB preliminarily prioritized the Laxemar subarea for further investigations. A programme was presented for the first stage of the complete site investigation in the Laxemar subarea, along with the main features of the remainder of the site investigation. The programme included investigations up until the summer of 2005 and was particularly aimed at obtaining answers to several vital questions so that the subsequent investigations could be focused on the rock areas judged to be most suitable for a final repository. These investigations have now been completed. This report presents the programme for the remainder of the site investigation. The points of departure are the general goals for the Deep Repository Project during the site investigation phase, analyses and evaluations of data from completed investigations, and the needs for additional data to be able to evaluate the site as a siting alternative for the final repository. The account mainly covers the investigations on the site. All other work - analyses, site descriptive modelling, facility design, safety assessments and studies and assessments of consequences for the environment, human health and society - are only mentioned to the extent necessary in order to place the investigations in their context. The direction of the site investigation in Oskarshamn and the investigation programme presented in this report is based on SKB's preliminary decision to prioritize the Laxemar subarea for further investigations. A final decision on the direction of the site investigation in Oskarshamn is planned to be made in the spring of 2006 when preliminary safety reports have been presented for both Simpevarp and Laxemar. If the decision should then be that the Simpevarp subarea is chosen, a new investigation programme and a new timetable will be prepared. The overall goal of the site investigation phase is to obtain the permits required to site and build the final repository. The site investigations must therefore provide the data required for an evaluation of the suitability of the investigated sites for a final repository. The material must accordingly be comprehensive enough to: Show whether the selected site satisfies fundamental safety requirements. Show whether the construction-related prerequisites are met. Permit the final repository to be adapted to the conditions and features on the site. Permit an assessment of the impact of the final repository on the environment and society. Permit comparisons between the two investigated sites - Forsmark and Simpevarp/Laxemar. According to SKB's plans, the site investigation in Oskarshamn will be concluded in the late summer of 2007. Monitoring will continue after this time. A large-scale interference test, combined with tracer tests, is also planned

  7. High variability of indoor radon concentrations in uraniferous bedrock areas in the Balkan region

    International Nuclear Information System (INIS)

    In this work the strong influence of geological factors on the variability of indoor radon is found in two of three geologically very different regions of South-Eastern Europe. A method to estimate the annual mean concentration when one seasonal measurement is missing is proposed. Large differences of radon concentrations in different rooms of the same house and significant difference in radon concentrations in one season comparing it to the others are noted in certain cases. Geological factors that can lead to such behavior are discussed

  8. TOLERANCE AS THE BEDROCK OF CONFESSIONAL AND SOCIOCULTURAL HARMONY IN AZERBAIJAN

    OpenAIRE

    Allakhverdieva, Aysel

    2008-01-01

    The author bases her conclusion that the experience of many centuries of peaceful coexistence of different ethnic groups and confessions in Azerbaijan can provide answers to the challenges of the globalizing world on her detailed analysis of the past and present of religious tolerance in this country.

  9. Dating methods and geochronology of fractures and movements in bedrock: a review

    Energy Technology Data Exchange (ETDEWEB)

    Tullborg, E.L. [Terralogica AB, Graabo (Sweden); Larson, Sven Aake [Goeteborgs Univ. (Sweden); Morad, S. [Uppsala Univ. (Sweden)

    2001-06-01

    Constraining the absolute and relative ages of crustal movements is of fundamental importance in evaluating the potentials of a site as a repository for spent radioactive fuel. In this report a review summary of up to date absolute and relative dating methods is presented with specific attention to those methods most amenable for dating of fractures. A review of major fracture-and shear zones in the Swedish part of the Baltic Shield is also given. Since the shield has suffered a long and complicated history, geo-chronologists are faced with the problem of reactivated zones when attempting to date these. It is important to get structural control in order to make the choice of dating method since different methods may give answer to completely different questions. An integration of all geological background data is necessary in order to make the proper chose to fit the raised question.

  10. Hydrodynamic factors affecting the persistence of the Exxon Valdez oil in a shallow bedrock beach

    Science.gov (United States)

    Xia, Yuqiang; Li, Hailong; Boufadel, Michel C.; Sharifi, Youness

    2010-10-01

    We report a field study and numerical modeling of multicomponent flow in a tidal gravel beach in Knight Island, Prince William Sound, Alaska, where oil from the 1989 Exxon Valdez oil spill persisted. Field measurements of water table, salinity, and tracer (lithium) concentration were obtained for around a week during the summer of 2008. The numerical model MARUN was used to simulate the field observations. On the basis of field experiments and numerical simulations, the beach was identified to have a two-layered hydraulic structure: a high-permeability surface layer underlain by a low-permeability lower layer. The hydraulic conductivity was found to be 5 × 10-2 m s-1 for the surface layer and 7 × 10-6 m s-1 for the lower layer. The simulations reproduced the observed water table, salinity, and lithium concentrations accurately. The small flow entering the beach from the land side resulted in a beach water table dropping below the interface of the two layers. This seems to be the major reason for the presence of oil in the lower layer. The exchange flow between the beach and the sea due to tidal influence was ˜2.12 m3 d-1 m-1. The patterns of inflow and outflow rates showed that the maximum seawater-groundwater exchange occurred in the middle to high intertidal zone, which explains the persistence of oil in the lower intertidal zone. To explore bioremediation of the beach with nutrient amendment, a numerical simulation of nutrient application on the beach surface was conducted, where the applied nutrient concentration was 5,000 mg L-1. The results showed that the nutrient concentration remaining in oiled areas after a week was larger than 50 mg L-1, which is larger than that needed for maximum microbial growth (2-10 mg L-1). This implies that the bioremediation via nutrient application on the beach surface could be adopted if nutrients were the only limiting factor.

  11. Field Indicators for the Prediction of Appalachian Soil and Bedrock Geochemistry

    OpenAIRE

    Johnson, Daniel Keith

    2016-01-01

    Surface mining for coal in the Central Appalachians contributes total dissolved solids (TDS) to headwater streams, especially below larger mines and associated valley fills. My objective was to characterize the geochemical properties of a range of surface soils and associated geologic strata from the Central Appalachian coalfields and to relate those properties to simple field indicators, such as color or rock type. I hypothesized that these indicators can accurately predict certain geochemi...

  12. Bedrock/Core, Base, Plus, and Threshold Strategies in the JFL Context

    Science.gov (United States)

    Grainger, P. R.

    2012-01-01

    Although research into language learning strategies over the past 30 years has provided many insights into how good language learners facilitate the language learning process, few studies have targeted learners of Japanese in a foreign language learning environment. This study sought to (1) identify the spoken communication strategies used by…

  13. Miscellaneous investigations series: Bedrock geologic map of the Lone Mountain pluton area, Esmeralda County, Nevada

    International Nuclear Information System (INIS)

    The joint attitudes were measured in the field and plotted on aerial photos at a scale of 1:24,000. The pluton is intensely jointed, primarily as a result of cooling and movement of the magma within a northwest-trending stress field. Foliation, in general, is poorly developed, and quality varies from area to area, but it is best developed close to the contacts with the metasedimentary rocks. A prominent northwest foliation direction was observed that parallels the northwest elongation of the exposed pluton. Faults in the pluton are difficult to identify because of the homogeneity of the rock. Several faults were mapped in the northern part of the area where they have a northeast trend and intersect the northwest-trending lamprophyre dikes with little apparent displacement. A major fault that bounds the northern part of the pluton is downthrown to the north and strikes northeast. This fault offsets the alluvium, the metasedimentary rocks, and the pluton and forms fault scraps as high as 10 m. Aeromagnetic data (US Geological Survey, 1979) suggest the following: (1) the local magnetic highs in the central part of the Lone Mountain pluton are probably related to topographic highs (peaks) where the flight lines are closer to the pluton; (2) a magnetic low in the northeastern part of Lone Mountain coincides with the pluton-country rock contact, which may be very steep; (3) the contours for the southwestern part of the mapped area indicate that the pluton-country rock contact is not as steep as that in the northeastern part and that the pluton probably coalesces at depth with the Weepah pluton, a pluton exposed south of the mapped area; and (4) the contours for the area of the Lone Mountain pluton express a northwest-trending gradient that parallels the northwest elongation of the Lone Mountain pluton and the northwest-trending stress field. 10 refs

  14. Dissolution of unirradiated UO2 fuel under simulated disposal conditions of spent fuel in crystalline granitic bedrock

    International Nuclear Information System (INIS)

    The solubility behavior of unirradiated UO2 pellets was studied under oxic (air-saturated) and anoxic (N2) conditions in deionized water, in sodium bicarbonate solutions with varying bicarbonate content (60 - 600 ppm), in Allard groundwater, simulating granitic fresh groundwater conditions, and in bentonite water, simulating the effects of bentonite on granitic fresh groundwater (25 deg C). The release of uranium was measured during static batch dissolution experiments of long duration (2 - 6 years). Under anoxic conditions, the oxidation state of uranium in solution was determined experimentally using a method based on the separation of the tetravalent and hexavalent states by ion-exchange chromatography in HCl medium, followed by analysis of each of the fractions by ICP-MS. A comparison was made with the theoretical solubility data calculated with the geochemical code, EQ3/6, in order to evaluate solubility (steady state) limiting factors. Under oxic conditions, various hypotheses for redox control (redox potential of the bulk solution or redox potential at the surface) were tested in the modelling calculations. Under oxic conditions, the measured concentrations for uranium at steady-state in deionized water were equal to the solubility of schoepite (pO2 = 0.2 atm). In NaHCO3 solutions with lower carbonate concentrations (0.98 - 1.96 mmol/l) and in Allard groundwater they were close to the calculated solubilities of U at the U3O7/U3O8 redox potential. In bentonite groundwater, the results suggest the formation of a secondary phase with a lower solubility. Only uranium oxide with a crystal structure of uraninite (UO2 - U3O7) was identified in all waters, when analysing particulate material in the solutions after contact with UO2 pellets. Under anoxic conditions, the measured concentrations at steady state were at the level of a mixed valence oxide, U4O9 (UO2.25) solubilities. The water composition had a minor effect on the solution concentration of uranium. According to the analyses of oxidation state at the end of the dissolution experiments, the uranium was mainly in the hexavalent state in the aqueous phase. (author)

  15. A field trip guidebook to the type localities of Marland Billings' 1935 Paleozoic bedrock stratigraphy near Littleton, New Hampshire

    Science.gov (United States)

    Rankin, Douglas W.; Rankin, Mary B.

    2014-01-01

    Marland Billings' classic paper published in 1937 in the Geological Society of America Bulletin established a succession of six stratigraphic units in rocks of low metamorphic grade near Littleton, New Hampshire. The two youngest units are fossiliferous in the area, with ages established at the time as “middle” Silurian and Early Devonian. Billings and students mapped the same stratigraphic section in adjacent areas of progressively higher regional metamorphic grade. This work laid the foundation upon which a major part of subsequent work in New England has been directly or indirectly built. This guidebook was written for a field trip held in March 2013 to visit roadcuts that are as close as possible in March to the type localities or areas of Billings’ six-fold stratigraphic succession. Ten stops are in rocks of chlorite grade of Acadian(?) metamorphism; the final stop visits amphibolite of the Ammonoosuc Volcanics. Fieldwork by the authors over the past 20 years confirms Billings’ broad conclusions.

  16. Deriving ice thickness, glacier volume and bedrock morphology of Austre Lovénbreen (Svalbard) using GPR

    OpenAIRE

    Saintenoy, A.; Friedt, J.-M.; Booth, A. D.; Tolle, F; Bernard, E; Laffly, D.; Laffly, Dominique; Marlin, C; Griselin, M.

    2013-01-01

    International audience Austre Lovénbreen is a 4.6 km2 glacier on the Archipelago of Svalbard (79o N) that has been surveyed over the last 47 years in order to monitor in particular the glacier evolution and associated hydrological phenomena in the context of nowadays global warming. A three-week field survey during April 2010 allowed for the acquisition of a dense mesh of ground-penetrating radar (GPR) data with an average of 14 683 points per km2 (67 542 points total) on the glacier surfa...

  17. Deriving ice thickness, glacier volume and bedrock morphology of the Austre Lov\\'enbreen (Svalbard) using Ground-penetrating Radar

    OpenAIRE

    Saintenoy, Albane; Friedt, J.-M.; Booth, Adam D.; Tolle, F; Bernard, E; Laffly, Dominique; Marlin, C; Griselin, M.

    2013-01-01

    The Austre Lov\\'enbreen is a 4.6 km2 glacier on the Archipelago of Svalbard (79 degrees N) that has been surveyed over the last 47 years in order of monitoring in particular the glacier evolution and associated hydrological phenomena in the context of nowadays global warming. A three-week field survey over April 2010 allowed for the acquisition of a dense mesh of Ground-penetrating Radar (GPR) data with an average of 14683 points per km2 (67542 points total) on the glacier surface. The profil...

  18. Recent contributions on Falkland Islands bedrock geology, with an inventory of representative lithostratigraphical specimens held by the British Geological Survey

    OpenAIRE

    Stone, P.

    2014-01-01

    After completion of the Falkland Islands geological mapping project in 1998, geological work on the islands by the British Geological Survey continued in support of onshore mineral exploration projects and to provide correlative data for the offshore hydrocarbons exploration programme. Academic research from British institutions has declined over the last decade, but international interest has increased, with research visits by geologists from Brazil, Australia and the USA. Results arising fr...

  19. SITE DEMONSTRATION OF ENHANCED IN SITU BIOREMEDIATION OF CHLORINATED AND NON-CHLORINATED ORGANIC COMPOUNDS IN FRACTURED BEDROCK

    Science.gov (United States)

    A field demonstration of an enhanced in situ bioremediation technology was conducted between March 1998 and August 1999 at the ITT Industries Nithg Vision (ITTNV) Division plant in Roanoke, Virginia. The bioremediation process was evaluated for its effectiveness in treating both ...

  20. Thermal properties Forsmark. Modelling stage 2.3 Complementary analysis and verification of the thermal bedrock model, stage 2

    International Nuclear Information System (INIS)

    This report present the results of thermal modelling work for the Forsmark area carried out during modelling stage 2.3. The work complements the main modelling efforts carried out during modelling stage 2.2. A revised spatial statistical description of the rock mass thermal conductivity for rock domain RFM045 is the main result of this work. Thermal modelling of domain RFM045 in Forsmark model stage 2.2 gave lower tail percentiles of thermal conductivity that were considered to be conservatively low due to the way amphibolite, the rock type with the lowest thermal conductivity, was modelled. New and previously available borehole data are used as the basis for revised stochastic geological simulations of domain RFM045. By defining two distinct thermal subdomains, these simulations have succeeded in capturing more of the lithological heterogeneity present. The resulting thermal model for rock domain RFM045 is, therefore, considered to be more realistic and reliable than that presented in model stage 2.2. The main conclusions of modelling efforts in model stage 2.3 are: - Thermal modelling indicates a mean thermal conductivity for domain RFM045 at the 5 m scale of 3.56 W/(mK). This is slightly higher than the value of 3.49 W/(mK) derived in model stage 2.2. - The variance decreases and the lower tail percentiles increase as the scale of observation increases from 1 to 5 m. Best estimates of the 0.1 percentile of thermal conductivity for domain RFM045 are 2.24 W/(mK) for the 1 m scale and 2.36 W/(mK) for the 5 m scale. This can be compared with corresponding values for domain RFM029 of 2.30 W/(mK) for the 1 m scale and 2.87 W/(mK)for the 5 m scale. - The reason for the pronounced lower tail in the thermal conductivity distribution for domain RFM045 is the presence of large bodies of the low-conductive amphibolite. - The modelling results for domain RFM029 presented in model stage 2.2 are still applicable. - As temperature increases, the thermal conductivity decreases. This temperature dependence tends to decrease as the thermal conductivity decreases. - Heat capacity: Domains RFM029 and RFM045 have a mean heat capacity of 2.06 MJ/(m3K) and 2.15 MJ/(m3K) respectively. - The mean in situ temperatures at 400 m, 500 m and 600 m depth are estimated at 10.5 deg C, 11.6 deg C, and 12.8 deg C respectively, and are therefore unchanged compared to model stage 2.2. - The estimates of the TRC (thermal rock class) proportions in domain RFM029 are considerably more reliable than those for domain RFM045. For the latter, the small number of boreholes in combination with the higher degree of lithological heterogeneity results in rather large uncertainties in the estimated proportions. - The aspect of the thermal model with the highest confidence is the thermal conductivity distribution of domain RFM029, because of its higher degree of lithological and thermal homogeneity compared to domain RFM045 - The aspect of the thermal model with the lowest confidence is the lower tail of the thermal conductivity distribution for rock domain RFM045. This uncertainty is related to the spatial and size distribution of amphibolite in domain RFM045

  1. Geochemical interactions between uranium-tailings fluids and subjacent bedrock. Canon City, Colorado: use of the computer model MINTEQ

    International Nuclear Information System (INIS)

    Contamination of domestic water wells by Mo, Se, SO4 and U has been documented in the vicinity of a uranium mill near Canon City, Colorado. Fluids collected from the tailings ponds were passed through cores of the subjacent calcite-bearing sandstone to determine the effect of pH and Eh on the mobility of Al, Ca, Cu, Fe, Mn, Mo, Se, SO4, V, U, and Zn. During Experiment 27 the pH initially increased from 2.3 to 8.0 as calcite in the core dissolved. Concurrently, iron hydroxide precipitated in the micro-environment surrounding the carbonate grains, effectively reducing the area of calcite exposed to the acidic eluent. This led to a decrease in pH to 3.4. Experiment 27 was modeled using the mass transfer computer program, MINTEQ. The pH was modeled by dissolving decreasing amounts of calcite to simulate the acidification of the system, while Eh was set at the levels measured in the experiments. Mn was adequately described by the dissolution of manganiferous calcite, but an adequate model for dissolved Ca required both calcite dissolution and ion-exchange of Ca by Na. Al was simulated by the solubility constraint imposed by an amorphous aluminum hydroxide above a pH of 6.0, ad by AIOHSO4 in more acidic regimes. Fe was modeled by the precipitation of an amorphous hydroxide. Zn was modeled using triple-layer sorption routine with an amorphous iron hydroxide phase as the sobent, but Cu could not be modeled using the same values for the triple-layer parameters. Se sorption is affected by both the mass of sorbent in the system and by competition for surface sites with sulfate ion. The experiments suggest that Se may be the best tracer of the escape and movement of raffinate in the aquifer at Canon City

  2. State of disequilibrium between 238U, 234U, 226Ra and 222Rn in groundwater from bedrock

    International Nuclear Information System (INIS)

    Approximately one thousand drilled wells were investigated for their natural radioactivity. The determinations of 238U, 234U, 226Ra and 222Rn from 310 samples showed a high state of radioactive disequilibrium between the members of the uranium series present in water. The 238U/226Ra activity ratio usually fell in the range 1 to 20 and the 238U/222Rn activity ratio in the range 1 to 20 x 10-4, the highest activity ratios being from samples with an elevated uranium content. The 234U/238U activity ratio varied between 0.76 and 4.67, the most frequent values showing a 60% excess of 234U in the samples. Most of the 234U/238U activity ratios near unity were found in samples with a high uranium content. Several drilled wells with anomalously high uranium contents were found in southern Finland. The average 226Ra and 222Rn contents of these wells were not exceptionally high, which suggests high mobility of uranium in groundwater from the areas involved. (author)

  3. Deriving ice thickness, glacier volume and bedrock morphology of the Austre Lov\\'enbreen (Svalbard) using Ground-penetrating Radar

    CERN Document Server

    Saintenoy, Albane; Booth, Adam D; Tolle, F; Bernard, E; Laffly, Dominique; Marlin, C; Griselin, M

    2013-01-01

    The Austre Lov\\'enbreen is a 4.6 km2 glacier on the Archipelago of Svalbard (79 degrees N) that has been surveyed over the last 47 years in order of monitoring in particular the glacier evolution and associated hydrological phenomena in the context of nowadays global warming. A three-week field survey over April 2010 allowed for the acquisition of a dense mesh of Ground-penetrating Radar (GPR) data with an average of 14683 points per km2 (67542 points total) on the glacier surface. The profiles were acquired using a Mala equipment with 100 MHz antennas, towed slowly enough to record on average every 0.3 m, a trace long enough to sound down to 189 m of ice. One profile was repeated with 50 MHz antenna to improve electromagnetic wave propagation depth in scattering media observed in the cirques closest to the slopes. The GPR was coupled to a GPS system to position traces. Each profile has been manually edited using standard GPR data processing including migration, to pick the reflection arrival time from the ic...

  4. Final disposal of spent nuclear fuel in the Finnish bedrock. Technical research and development in the period 1993-1996

    International Nuclear Information System (INIS)

    Planning activity relating to the disposal of spent fuel from the Teollisuuden Voima Oy (TVO) and Imatran Voima Oy (IVO) nuclear power plants in Finland is targeted at selection of the site for final disposal in the year 2000, with final disposal actually beginning in 2020. The report describes the research and development work carried out in the years 1993-1996, the current revised concept for final disposal technology and the research and development programme for the period 1997-2000. (refs.)

  5. Bedrock K{sub d} data and uncertainty assessment for application in SR-Site geosphere transport calculations

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, James (Kemakta Konsult AB, Stockholm (Sweden))

    2010-12-15

    The safety assessment SR-Site is undertaken to assess the safety of a potential geologic repository for spent nuclear fuel at the Forsmark and Laxemar sites. The present report is one of several reports that form the data input to SR-Site and contains a compilation of recommended K{sub d} data (i.e. linear partitioning coefficients) for safety assessment modelling of geosphere radionuclide transport. The data are derived for rock types and groundwater compositions distinctive of the site investigation areas at Forsmark and Laxemar. Data have been derived for all elements and redox states considered of importance for far-field dose estimates as described in /SKB 2010d/. The K{sub d} data are given in the form of lognormal distributions characterised by a mean (mu) and standard deviation (sigma). Upper and lower limits for the uncertainty range of the recommended data are defined by the 2.5% and 97.5% percentiles of the empirical data sets. The best estimate K{sub d} value for use in deterministic calculations is given as the median of the K{sub d} distribution

  6. The impact of Norway spruce planting on herb vegetation in the mountain beech forests on two bedrock types

    Czech Academy of Sciences Publication Activity Database

    Máliš, František; Ujházy, K.; Vodálová, A.; Barka, I.; Čaboun, V.; Sitková, Z.

    2012-01-01

    Roč. 131, č. 5 (2012), s. 1551-1569. ISSN 1612-4669 Institutional support: RVO:67985939 Keywords : boreal forests * Bavarian Alps * temperate forests * soil * biodiversity * nitrogen mineralizaton Subject RIV: EF - Botanics Impact factor: 1.959, year: 2012

  7. Iceland hotspot track in southeast Greenland causes huge present-day vertical viscoelastic motion of the bedrock

    Science.gov (United States)

    Khan, Shfaqat Abbas; Sasgen, Ingo; Bevis, Michael; van Dam, Tonie; Wahr, John; Bamber, Jonathan; Wouters, Bert; Helm, Veit; Willis, Michael; Csatho, Beata; Knudsen, Per; Kuipers Munneke, Peter; Kjær, Kurt

    2016-04-01

    The process of Glacial Isostatic Adjustment (GIA) represents the ongoing response of the solid Earth to past ice mass loss that occurred following the Last Glacial Maximum (LGM, ~21 ka B.P.). The magnitude of the GIA uplift depends on the temporal history of the ice load and is highly sensitive to variations in upper mantle viscosity. Greenland GIA is thought to be well contained and due to relative high viscosity, influence of more recent changes e.g. since the Little Ice Age have minor present-day effect (uplift due to recent ice mass changes. We reconsider the evolution of the Greenland ice sheet since LGM and estimate a total ice mass loss equivalent to sea level rise of 4.9 m since LGM. Our observations suggest southeast and northwest Greenland, subject to present-day major ice loss, also contributed by significantly more mass loss on millennia scale than previously estimated.

  8. Final disposal of spent fuel in the Finnish bedrock. Scope and requirements for site-specific safety analysis

    International Nuclear Information System (INIS)

    The report is a summary of the research conducted in the period 1993 to 1996 into safety of spent fuel final disposal. The principal goal of the research in this period, as set in 1993, was to develop a strategy for site-specific safety analysis. At the same time efforts were to be continued to gather data and validate the technical approach for the analysis. The work aimed at having the data needed for the analysis available at the end of year 1998. A safety assessment update, TILA-96, prepared by VTT Energy, is published as a separate report. The assessment is based on the TVO-92 safety analysis, but takes into account the knowledge acquired after 1992 on safety aspects of the disposal system and the data gathered from the site investigations made by TVO and from the beginning of 1996, by Posiva. Since the site investigations are still ongoing and much of the data gathered still pending interpretation, only limited amount of new site-specific information has been available for the present assessment. (172 refs.)

  9. Study on the rupture characteristics of the overlaying soil with soft interlayer due to fault bedrock dislocation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Lei; LI Xiao-jun; HUO Da

    2006-01-01

    In this paper, the rupture characteristics of the overlaying soil with soft interlayer were studied by plane-strain finite element method. From the results, it can be shown that the existence of soft layer separates rupture process of the overlaying soil into two phases. The depth of a buried soft interlayer will influence the rupture process and the rupture range of the overlaying soil. The deeply buried soft interlayer would bring about a wider range of surface failure. In addition, the thickness of the soft layer also has effect on the rupture process and rupture range of the overlaying soil.

  10. Thermal properties Forsmark. Modelling stage 2.3 Complementary analysis and verification of the thermal bedrock model, stage 2.

    Energy Technology Data Exchange (ETDEWEB)

    Sundberg, Jan; Wrafter, John; Laendell, Maerta (Geo Innova AB (Sweden)); Back, Paer-Erik; Rosen, Lars (Sweco AB (Sweden))

    2008-11-15

    This report present the results of thermal modelling work for the Forsmark area carried out during modelling stage 2.3. The work complements the main modelling efforts carried out during modelling stage 2.2. A revised spatial statistical description of the rock mass thermal conductivity for rock domain RFM045 is the main result of this work. Thermal modelling of domain RFM045 in Forsmark model stage 2.2 gave lower tail percentiles of thermal conductivity that were considered to be conservatively low due to the way amphibolite, the rock type with the lowest thermal conductivity, was modelled. New and previously available borehole data are used as the basis for revised stochastic geological simulations of domain RFM045. By defining two distinct thermal subdomains, these simulations have succeeded in capturing more of the lithological heterogeneity present. The resulting thermal model for rock domain RFM045 is, therefore, considered to be more realistic and reliable than that presented in model stage 2.2. The main conclusions of modelling efforts in model stage 2.3 are: - Thermal modelling indicates a mean thermal conductivity for domain RFM045 at the 5 m scale of 3.56 W/(mK). This is slightly higher than the value of 3.49 W/(mK) derived in model stage 2.2. - The variance decreases and the lower tail percentiles increase as the scale of observation increases from 1 to 5 m. Best estimates of the 0.1 percentile of thermal conductivity for domain RFM045 are 2.24 W/(mK) for the 1 m scale and 2.36 W/(mK) for the 5 m scale. This can be compared with corresponding values for domain RFM029 of 2.30 W/(mK) for the 1 m scale and 2.87 W/(mK)for the 5 m scale. - The reason for the pronounced lower tail in the thermal conductivity distribution for domain RFM045 is the presence of large bodies of the low-conductive amphibolite. - The modelling results for domain RFM029 presented in model stage 2.2 are still applicable. - As temperature increases, the thermal conductivity decreases. This temperature dependence tends to decrease as the thermal conductivity decreases. - Heat capacity: Domains RFM029 and RFM045 have a mean heat capacity of 2.06 MJ/(m3K) and 2.15 MJ/(m3K) respectively. - The mean in situ temperatures at 400 m, 500 m and 600 m depth are estimated at 10.5 deg C, 11.6 deg C, and 12.8 deg C respectively, and are therefore unchanged compared to model stage 2.2. - The estimates of the TRC (thermal rock class) proportions in domain RFM029 are considerably more reliable than those for domain RFM045. For the latter, the small number of boreholes in combination with the higher degree of lithological heterogeneity results in rather large uncertainties in the estimated proportions. - The aspect of the thermal model with the highest confidence is the thermal conductivity distribution of domain RFM029, because of its higher degree of lithological and thermal homogeneity compared to domain RFM045 - The aspect of the thermal model with the lowest confidence is the lower tail of the thermal conductivity distribution for rock domain RFM045. This uncertainty is related to the spatial and size distribution of amphibolite in domain RFM045

  11. Seismic effects on bedrock and underground constructions. A literature survey of damage on constructions; Changes in groundwater levels and flow; Changes in chemistry in groundwater and gases

    International Nuclear Information System (INIS)

    This report is a literature review of direct and indirect effects of earthquakes on underground constructions as tunnels, caverns and mines. The direct damage will cause vibrations, shaking and displacement, which may lead to partial or total destruction of the underground facility. Damage caused by shaking has been reported in several studies, and several hundreds of events have been reported both from mines and tunnels. These reports are mainly from active earthquake areas. There are very few reports of damage caused by displacements on an existing fault. The damage, which may be severe, is generally concentrated to the vicinity of the fault zone. The report also includes a review of the effects caused by earthquakes on groundwater level, flow, pressure, chemistry and constituents in the ground. Such changes are mainly reported from studies in wells near active faults. The interesting coupling of changes in groundwater characteristics around an underground construction is, unfortunately, very seldom reported. The groundwater level and pressure changes are discussed in Chapter 4. The bases for this part of the review is taken from the Alaska earthquake 1964. Other observations are reported from wells and reservoirs located near existing faults. Changes of the geochemistry in groundwater and soil gases are reviewed in Chapter 4. The mechanisms of seismochemical anomalies are discussed and examples of short and long term monitoring are given from USA, Soviet Union and China. Gases in ground water and soil is reported in Chapter 5. Radon is so far one of the most studied species and its variation in short, medium and long term with seismic activity is rather well understood. Other gases or isotopes that have been studied include helium, carbon dioxide, hydrogen, argon and methane, radium and uranium. The paper also includes same statements for repository design based on the result of the review. (81 refs.)

  12. Final disposal of spent fuel in the Finnish bedrock. Scope and requirements for site-specific safety analysis; Kaeytetyn polttoaineen loppusijoitus Suomen kallioperaeaen. Paikkakohtaisen turvallisuusanalyysin edellytykset ja mahdollisuudet

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    The report is a summary of the research conducted in the period 1993 to 1996 into safety of spent fuel final disposal. The principal goal of the research in this period, as set in 1993, was to develop a strategy for site-specific safety analysis. At the same time efforts were to be continued to gather data and validate the technical approach for the analysis. The work aimed at having the data needed for the analysis available at the end of year 1998. A safety assessment update, TILA-96, prepared by VTT Energy, is published as a separate report. The assessment is based on the TVO-92 safety analysis, but takes into account the knowledge acquired after 1992 on safety aspects of the disposal system and the data gathered from the site investigations made by TVO and from the beginning of 1996, by Posiva. Since the site investigations are still ongoing and much of the data gathered still pending interpretation, only limited amount of new site-specific information has been available for the present assessment. (172 refs.).

  13. Deriving ice thickness, glacier volume and bedrock morphology of the Austre Lovénbreen (Svalbard) using Ground-penetrating Radar

    OpenAIRE

    Saintenoy, Albane; Friedt, Jean-Michel; Booth, Adam; Tolle, Florian; Bernard, Eric; Laffly, Dominique; Marlin, Christelle; Madeleine GRISELIN

    2013-01-01

    International audience The Austre Lovénbreen is a 4.6 km2 glacier on the Archipelago of Svalbard (79°N) that has been surveyed over the last 47 years in order of monitoring in particular the glacier evolution and associated hydrological phenomena in the context of nowadays global warming. A three-week field survey over April 2010 allowed for the acquisition of a dense mesh of Ground-penetrating Radar (GPR) data with an average of 14683 points per km2 (67542 points total) on the glacier sur...

  14. Mineralogy of Juventae Chasma: Sulfates in the light-toned mounds, mafic minerals in the bedrock, and hydrated silica and hydroxylated ferric sulfate on the plateau

    Science.gov (United States)

    Bishop, Janice L.; Parente, Mario; Weitz, Catherine M.; Noe Dobrea, Eldar Z.; Roach, Leah H.; Murchie, Scott L.; McGuire, Patrick C.; McKeown, Nancy K.; Rossi, Christopher M.; Brown, Adrian J.; Calvin, Wendy M.; Milliken, Ralph; Mustard, John F.

    2009-11-01

    Juventae Chasma contains four light-toned sulfate-bearing mounds (denoted here as A-D from west to east) inside the trough, mafic outcrops at the base of the mounds and in the wall rock, and light-toned layered deposits of opal and ferric sulfates on the plateau. Hyperspectral visible/near-infrared Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectra were used to identify monohydrated and polyhydrated sulfate (PHS) outcrops of layered material on the bright mounds. Most of the monohydrated sulfate signatures closely resemble those of szomolnokite (FeSO4·H2O), characterized by a water band near 2.08 μm, while some areas exhibit spectral features more similar to those of kieserite (MgSO4·H2O), with a band centered closer to 2.13 μm. The largest PHS outcrops occur on the top of mound B, and their spectral features are most consistent with ferricopiapite, melanterite, and starkeyite, but a specific mineral cannot be uniquely identified at this time. Coordinated analyses of CRISM maps, Mars Orbiter Laser Altimeter elevations, and High Resolution Imaging Science Experiment images suggest that mounds A and B may have formed together and then eroded into separate mounds, while mounds C and D likely formed separately. Mafic minerals (low-Ca pyroxene, high-Ca pyroxene, and olivine) are observed in large ˜2-10 km wide outcrops in the wall rock and in smaller outcrops ˜50-500 m across at the floor of the canyon. Most of the wall rock is covered by at least a thin layer of dust and does not exhibit strong features characteristic of these minerals. The plateau region northwest of Juventae Chasma is characterized by an abundance of light-toned layered deposits. One region contains two spectrally unique phases exhibiting a highly stratified, terraced pattern. CRISM spectra of one unit eroded into swirling patterns with arc-like ridges exhibit a narrow 2.23-μm band assigned to hydroxylated ferric sulfate. A thin layer of a fractured material bearing an opaline silica phase is observed at the contact between the older plateau unit and the younger hydroxylated ferric sulfate-bearing light-toned layered deposits. Hydrothermal processes may have produced an acidic environment that fostered formation of the hydrated silica and hydroxylated ferric sulfate units.

  15. Hydraulic modelling and flood inundation mapping in a bedrock-confined anabranching network: the Mekong River in the Siphandone Wetlands, Laos

    OpenAIRE

    Van, Tri Pham Dang

    2010-01-01

    Anabranching fluvial networks recently have become the focus of attention from environmental specialists, especially in the hydraulic field. Anabranching networks can be found in different physical environments; however, the hydraulic and geomorphological natures of such river networks are still not well known leading to on-going discussions on the definition and nature of the networks. Even though, alluvial anabranching networks generally have common features like vegetated is...

  16. Variability of parameters for modelling soil moisture conditions. Studies on loamy to silty soils on marly bedrock in the Ardèche drainage basin (France).

    NARCIS (Netherlands)

    Berg, van den J.A.

    1989-01-01

    Field experiments and additional measurements on undisturbed soil samples in the laboratory were done to investigate the variability of the parameters used in modelling soil moisture conditions.The conditions of soil water control the amount of moisture available for the plant cover, crop production

  17. Bedrock and surficial geologic map of the Satan Butte and Greasewood 7.5’ quadrangles, Navajo and Apache Counties, northern Arizona

    Science.gov (United States)

    Amoroso, Lee; Priest, Susan S.; Hiza-Redsteer, Margaret

    2013-01-01

    The geologic map of the Satan Butte and Greasewood 7.5’ quadrangles is the result of a cooperative effort of the U.S. Geological Survey (USGS) and the Navajo Nation to provide regional geologic information for management and planning officials. This map provides geologic information useful for range management, plant and animal studies, flood control, water resource investigations, and natural hazards associated with sand-dune mobility. The map provides connectivity to the regional geologic framework of the Grand Canyon area of northern Arizona. The map area encompasses approximately 314 km2 (123 mi2) within Navajo and Apache Counties of northern Arizona and is bounded by lat 35°37'30" to 35°30' N., long 109°45' to 110° W. The quadrangles lie within the southern Colorado Plateau geologic province and within the northeastern portion of the Hopi Buttes (Tsézhin Bií). Large ephemeral drainages, Pueblo Colorado Wash and Steamboat Wash, originate north of the map area on the Defiance Plateau and Balakai Mesa respectively. Elevations range from 1,930 m (6,330 ft) at the top of Satan Butte to about 1,787 m (5,860 ft) at Pueblo Colorado Wash where it exits the southwest corner of the Greasewood quadrangle. The only settlement within the map area is Greasewood, Arizona, on the north side of Pueblo Colorado Wash. Navajo Highway 15 crosses both quadrangles and joins State Highway 264 northwest of Ganado. Unimproved dirt roads provide access to remote parts of the Navajo Reservation.

  18. Determining the origin of enigmatic bedrock structures using apatite (U-Th)/He thermochronology: Alabama and Poverty Hills, Owens Valley, California

    Science.gov (United States)

    Ali, G. A.; Reiners, P. W.; Ducea, M.

    2008-12-01

    The Alabama and Poverty Hills are enigmatic, topographic highs of crystalline basement surrounded by Neogene sediments in Owens Valley, California. The 150-km long Owens Valley, the westernmost graben of the Basin and Range Province, initiated at about 3 Ma, creating ~2-4 km of vertical relief from the Sierra Nevada and White/Inyos crests to the valley floor. Along the valley, the active right-lateral Owens Valley Fault Zone (OVFZ) accommodates a significant portion of Pacific-North American plate motion, creating an oblique dextral fault zone, with localized transpression along minor left-stepovers. The dominantly granitic Mesozoic rocks of the Alabama Hills are bounded by the OVFZ to the east, and the granitic and metavolcanic Mesozoic rocks of the Poverty Hills are located along an apparent 3-km left stepover of the OVFZ. The tectonic origin and geodynamic significance of both these structures are not known, but previously published hypotheses include: 1) transpressional uplifts as OVFZ-related flower structures; 2) down-dropped normal fault blocks; and 3) giant landslides from adjacent ranges. We measured apatite (U-Th)/He ages on 15 samples from the Alabama and Poverty Hills to understand the history of shallow crustal exhumation of these structures, and to potentially correlate them to rocks from adjacent ranges. Apatite He dating typically yields cooling ages corresponding to closure temperatures of ~55-65 °C, corresponding roughly to depths of ~2-3 km in the crust. The majority of apatite He ages from the Alabama Hills ranged from 58-70 Ma, but the far eastern, and lowest elevation sample showed ages of 51-55 Ma. The Poverty Hills shows younger ages of 40-65 Ma and no recognizable spatial pattern. Although the data do not conclusively rule out a transpressional uplift origin of the Poverty Hills, the rocks within them could not have been exhumed from depths greater than ~2-3 km in Owens Valley. Data from both structures are most consistent with down-dropping from adjacent ranges. Apatite He ages in the Alabama Hills correlate with He ages of rocks about 2.5-3 km higher, near Mt. Whitney in the adjacent Sierra Nevada. This, coupled with the spatial pattern of ages, strongly suggests that the Alabama Hills are a down-dropped normal fault block along the Sierra Nevada frontal fault zone or a related fault. A structural reconstruction using tilt-corrected Sierran apatite He age-elevation correlations requires 2.6 km of vertical, and 1.5 km of eastward motion for the Alabama Hills. The proximity of this extensive down- dropped basement block, directly east of the highest topography in the Sierra Nevada, suggests the possibility of localized isostatic response as a cause for locally high elevation in the Mt. Whitney area.

  19. The mobility of uranium from U-containing bedrock materials as a function of pH: Implications for tunnel construction

    OpenAIRE

    Helmers, Tari Anne

    2013-01-01

    According to amendments made to the Norwegian Pollution Control Act in 2011, naturally occurring radioactive material (NORM) is now to be considered as an environmental contaminant, in addition to organic pollutants and trace metals. Alum shale areas are rich in radionuclides and, thus, must now be treated as contaminant sources. The substrate media analyzed in this work was collected from a future tunnel construction site that is being built in the Gran municipality on Highway Rv4. The...

  20. Hydrogeological Importance of Bedrock Sediments to the Community and Growth of Sugar Cane in Fadama Rake Area of Madagali, Northeast Nigeria

    OpenAIRE

    Gaiya Stephen; S.C. Alkali

    2014-01-01

    Thirty Vertical Electrical Sounding (VES) points were sited on the alluvial plain of Madagali fadama area. This was aimed at establishing the lithological character of the drainage plain and its contributions to the growth of sugar cane. 1X1D shareware package was used to interpret the curves. Over the floodplain, potential recharge water into the subsurface units probably takes place through migration routes of coarse-grained colluvial deposits which act as effective soak away for surface ru...

  1. Final disposal of spent nuclear fuel in the Finnish bedrock. Technical research and development in the period 1993-1996; Kaeytetyn polttoaineen loppusijoitus Suomen kallioperaeaen. Tekniikkatutkimukset vuosina 1993-1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    Planning activity relating to the disposal of spent fuel from the Teollisuuden Voima Oy (TVO) and Imatran Voima Oy (IVO) nuclear power plants in Finland is targeted at selection of the site for final disposal in the year 2000, with final disposal actually beginning in 2020. The report describes the research and development work carried out in the years 1993-1996, the current revised concept for final disposal technology and the research and development programme for the period 1997-2000. (refs.).

  2. Structure contours of top of Laramie-Fox Hills aquifer in "Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of Denver Basin, Colorado." Hydrologic Atlas 742

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital geospatial data set consists of structure contours of the top of the Laramie-Fox Hills aquifer along the Front Range of Colorado. The U.S. Geological...

  3. Rapid Last Glacial Maximum deglaciation in the Indian Himalaya coeval with midlatitude glaciers: New insights from 10Be-dating of ice-polished bedrock surfaces in the Chandra Valley, NW Himalaya

    Science.gov (United States)

    Eugster, Patricia; Scherler, Dirk; Thiede, Rasmus C.; Codilean, Alexandru T.; Strecker, Manfred R.

    2016-02-01

    Despite a large number of dated glacial landforms in the Himalaya, the ice extent during the global Last Glacial Maximum (LGM) from 19 to 23 ka is only known to first order. New cosmogenic 10Be exposure ages from well-preserved glacially polished surfaces, combined with published data, and an improved production rate scaling model allow reconstruction of the LGM ice extent and subsequent deglaciation in the Chandra Valley of NW India. We show that a >1000 m thick valley glacier retreated >150 km within a few thousand years after the onset of LGM deglaciation. By comparing the recession of the Chandra Valley Glacier and other Himalayan glaciers with those of Northern and Southern Hemisphere glaciers, we demonstrate that post-LGM deglaciation was similar and nearly finished prior to the Bølling/Allerød interstadial. Our study supports the view that many Himalayan glaciers advanced during the LGM, likely in response to global variations in temperature.

  4. Safe Construction Tecnology for Freezing Bedrock Section in Main Shaft of Guotun Coal Mine%郭屯煤矿主井井筒深厚冻结基岩段安全施工技术

    Institute of Scientific and Technical Information of China (English)

    史建华; 宋文鹏

    2007-01-01

    冻结基岩施工过程中的关键是冻结壁的安全,充分应用光面爆破技术,保证冻结壁安全,以提高安全生产效率、速度和经济效益.对类似情况具有一定的指导意义.

  5. This geospatial data set consists of the bedrock formations of the High Plains aquifer, which underlies parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These files contain information acquired from a digital dataset of the Conterminous United States. This dataset represents geology of the High Plains study region....

  6. Structure contours of base of upper Arapahoe aquifer in "Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado." Hydrologic Atlas 742

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital geospatial data set consists of structure contours on the base of the upper member of the Arapahoe aquifer. The U.S. Geological Survey developed this...

  7. Modeling soil moisture processes and recharge under a melting snowpack

    Science.gov (United States)

    Flint, A.L.; Flint, L.E.; Dettinger, M.D.

    2008-01-01

    Recharge into granitic bedrock under a melting snowpack is being investigated as part of a study designed to understand hydrologic processes involving snow at Yosemite National Park in the Sierra Nevada Mountains of California. Snowpack measurements, accompanied by water content and matric potential measurements of the soil under the snowpack, allowed for estimates of infiltration into the soil during snowmelt and percolation into the bedrock. During portions of the snowmelt period, infiltration rates into the soil exceeded the permeability of the bedrock and caused ponding to be sustained at the soil-bedrock interface. During a 5-d period with little measured snowmelt, drainage of the ponded water into the underlying fractured granitic bedrock was estimated to be 1.6 cm d?1, which is used as an estimate of bedrock permeability. The numerical simulator TOUGH2 was used to reproduce the field data and evaluate the potential for vertical flow into the fractured bedrock or lateral flow at the bedrock-soil interface. During most of the snowmelt season, the snowmelt rates were near or below the bedrock permeability. The field data and model results support the notion that snowmelt on the shallow soil overlying low permeability bedrock becomes direct infiltration unless the snowmelt rate greatly exceeds the bedrock permeability. Late in the season, melt rates are double that of the bedrock permeability (although only for a few days) and may tend to move laterally at the soil-bedrock interface downgradient and contribute directly to streamflow. ?? Soil Science Society of America.

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

    Institute of Scientific and Technical Information of China (English)

    叶浩; Merlain Houketchang Bouyo; 赵越; 刘健

    2014-01-01

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

  9. Glaciers, Rhode Island Glacial Deposits; s44ggl88; This dataset shows Rhode Island glacial deposits, such as outwash and till deposits, and some but not all bedrock outcrops, Published in 1989, 1:12000 (1in=1000ft) scale, State of Rhode Island and Providence Plantations.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Glaciers dataset, published at 1:12000 (1in=1000ft) scale, was produced all or in part from Hardcopy Maps information as of 1989. It is described as 'Rhode...

  10. Applications of ERTS imagery to mappings sediments of the Twin Cities Metropolitan area

    Science.gov (United States)

    Poppe, J. R.

    1975-01-01

    ERTS images were compared to surficial geologic maps, prepared through traditional field studies. Lithologic boundaries, bedrock outcrops, bedrock structures, and geomorphologic features were examined. An area southeast of the Twin Cities, located chiefly in northern Dakota County was studied, as well as the New Brighton 15-minute quadrangle located in portions of Ramsey and Anoka Counties. Visual comparison of geologic maps and ERTS imagery demonstrated the limitations of this approach to geological investigations. Bedrock outcrops and bedrock structure in the metropolitan area do not appear on ERTS imagery. However, certain glacial sediments can be identified and are potentially mappable. Certain geomorphological features were also discernable.

  11. Lithologic controls on valley width and strath terrace formation

    Science.gov (United States)

    Schanz, Sarah A.; Montgomery, David R.

    2016-04-01

    Valley width and the degree of bedrock river terrace development vary with lithology in the Willapa and Nehalem river basins, Pacific Northwest, USA. Here, we present field-based evidence for the mechanisms by which lithology controls floodplain width and bedrock terrace formation in erosion-resistant and easily friable lithologies. We mapped valley surfaces in both basins, dated straths using radiocarbon, compared valley width versus drainage area for basalt and sedimentary bedrock valleys, and constructed slope-area plots. In the friable sedimentary bedrock, valleys are 2 to 3 times wider, host flights of strath terraces, and have concavity values near 1; whereas the erosion-resistant basalt bedrock forms narrow valleys with poorly developed, localized, or no bedrock terraces and a channel steepness index half that of the friable bedrock and an average channel concavity of about 0.5. The oldest dated strath terrace on the Willapa River, T2, was active for nearly 10,000 years, from 11,265 to 2862 calibrated years before present (cal YBP), whereas the youngest terrace, T1, is Anthropocene in age and recently abandoned. Incision rates derived from terrace ages average 0.32 mm y- 1 for T2 and 11.47 mm y- 1 for T1. Our results indicate bedrock weathering properties influence valley width through the creation of a dense fracture network in the friable bedrock that results in high rates of lateral erosion of exposed bedrock banks. Conversely, the erosion-resistant bedrock has concavity values more typical of detachment-limited streams, exhibits a sparse fracture network, and displays evidence for infrequent episodic block erosion and plucking. Lithology thereby plays a direct role on the rates of lateral erosion, influencing valley width and the potential for strath terrace planation and preservation.

  12. Holocene glacial history of the west Greenland Ice Sheet inferred from cosmogenic exposure ages and threshold lakes

    DEFF Research Database (Denmark)

    Larsen, Nicolaj Krog; Kjaer, K. H.; Colding, Sune Oluf;

    2011-01-01

    . Boulder samples from the highest peaks demonstrate that the ice was warm-based whereas bedrock samples often contain an inherited signal. These results may have implications for other studies in Greenland, which have inferred thin LGM ice based on 10Be ages of bedrock samples. The threshold lakes are used...

  13. Weathering of plagioclase across variable flow and solute transport regimes

    NARCIS (Netherlands)

    Pacheco, F.A.L.; Weijden, C.H. van der

    2012-01-01

    The study area is situated in a fault zone with fractured granites and metasediments. In a conceptual model, infiltrating water first passes the bedrock cover of soil and saprolite and then partly enters the fractures. Weathering reactions of minerals occur in small pores and fissures in the bedrock

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

    Science.gov (United States)

    Fitterman, D.V.

    1987-01-01

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

  15. Effects of glacial meltwater on corrosion of copper canisters

    International Nuclear Information System (INIS)

    The composition of glacial meltwater and its reactions in the bedrock are examined. The evidences that there are or should be from past intrusions of glacial meltwater and oxygen deep in the bedrock are also considered. The study is concluded with an evaluation of the potential effects of oxygenated meltwater on the corrosion of copper canisters. (46 refs., 3 figs., 2 tabs.)

  16. Rapid Gorge Formation in an Artificially Created Waterfall

    Science.gov (United States)

    Anton, L.; Mather, A. E.; Stokes, M.; Munoz Martin, A.

    2014-12-01

    A number of studies have examined rates of gorge formation, nick point retreat, and the controls on those rates via bedrock erodibility, the effectiveness of bedrock erosion mechanisms and the role of hillslope processes. Most findings are based on conceptual / empirical models or long term landscape analysis; but studies of recent quantifiable events are scarce yet highly valuable. Here we present expert eye witness account and quantitative survey of large and rapid fluvial erosion events that occurred over an artificially created waterfall at a spillway mouth. In 6 years a ~270 m long, ~100 m deep and ~100 to 160 m wide canyon was carved, and ~1.58 x106 m3 of granite bedrock was removed from the spillway site. Available flow data indicates that the erosion took place under unremarkable flood discharge conditions. The analysis of historic topographic maps enables the reconstruction of the former topography and successive erosion events, enabling the quantification of bedrock erosion amounts, and rates. Analysis of bedrock erodibility and discontinuity patterns demonstrates that the bedrock is mechanically strong, and that similar rock strength and fracture patterns are found throughout the region. It is apparent that structural pre-conditioning through fracture density and orientation in relation to flow and slope direction is of paramount importance in the gorge development. The presented example provides an exceptional opportunity for studying the evolution process of a bedrock canyon and to precisely measure the rate of bedrock channel erosion over a six year period. Results illustrate the highly episodic nature of the erosion and highlight several key observations for the adjustability of bedrock rivers. The observations have implications for the efficiency of bedrock erosion and raise important questions about incision rates, driving mechanisms and timescale assumptions' in models of landscape change.

  17. Evidence for biotic controls on topography and soil production

    Science.gov (United States)

    Roering, Joshua J.; Marshall, Jill; Booth, Adam M.; Mort, Michele; Jin, Qusheng

    2010-09-01

    The complex interplay of biological, physical, and chemical processes in pedogenesis and hillslope evolution limits our ability to predict and interpret landscape dynamics. Here, we synthesize a suite of observations from the steep, forested Oregon Coast Range to analyze the role of trees in topographic modification and bedrock-to-soil conversion. Using topographic data derived from airborne lidar, we demonstrate that the topographic signature of forest-driven soil and bedrock disturbance is pervasive. For length scales greater than 7.5 m, the land surface is defined by ridge-valley landforms, whereas smaller scales are dominated by pit-mound features generated by the turnover of large coniferous trees. From field surveys, the volume of bedrock incorporated in overturned rootwads increases rapidly with diameter for large conifers, reflecting the highly nonlinear increase in root biomass with tree diameter. Because trees younger than 60 years detach negligible bedrock, short timber harvest intervals may limit the extent to which root systems penetrate bedrock and facilitate bedrock fracturing and biogeochemical weathering. Using ground-penetrating radar, we show that the rootwads of large trees root achieve substantial penetration (1-3 m) into shallow bedrock. The radar transects also reveal that variations in soil thickness have characteristic length scales of 1 to 5 m, consistent with the scale of large rootwads, indicating that both the landscape surface and soil-bedrock interface exhibit a biogenic imprint. In our study area, the residence time of bedrock within dense rooting zones directly below large trees is similar to the time required for trees to occupy the entire forest floor through multiple cycles of forest succession, suggesting that biological modification of shallow bedrock is ubiquitous. Given increases in erosion rate, the ability of roots to initiate soil production may decline as bedrock exhumation through the biotic zone is rapid relative to the

  18. Geologic factors and house construction practices affecting indoor radon in Onondaga County, New York

    International Nuclear Information System (INIS)

    Indoor radon in Onondaga County, New York is largely controlled by bedrock and surficial geology. At more local scales, these alone are insufficient to characterize indoor radon potential. This paper reports on a detailed study of the concentration of indoor radon, soil radium, soil-gas radon, soil and bedrock type, permeability, and home construction practices indicates that above-average indoor radon concentrations are associated with gravelly moraine and glaciofluvial deposits, the radium-bearing Marcellus Shale, and high permeability zones around the substructure of houses built into limestone bedrock

  19. Map Service Showing Geology and Geologic Provinces of the Arabian Peninsula

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The geology data set for this map includes arcs, polygons, and labels that outline and describe the general geologic age and type of bedrock of the Arabian...

  20. Generalized Geology of Svalbard (geo_sval)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This coverage includes arcs, polygons, and polygon labels that describe the generalized geologic age of surface outcrops of bedrock of Svalbard. It also includes...

  1. Faults of Europe including Turkey (flt4_2l)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This coverage includes arcs that describe faults found in the surface outcrops of bedrock of Europe including Turkey (Albania, Andorra, Austria, Belgium, Bosnia and...

  2. Site characterization for urban seismic hazards in lower Manhattan, New York City, from microtremor array analysis

    Science.gov (United States)

    Stephenson, W.J.; Hartzell, S.; Frankel, A.D.; Asten, M.; Carver, D.L.; Kim, W.Y.

    2009-01-01

    We characterize the shear-wave velocity (Vs) of soil deposits in lower Manhattan at six sites using the SPAC and HVSR microtremor methods. The soil Vs ranges from 140 m/s to 300 m/s over bedrock. We believe that bedrock depth is constrained to ±15% with these microtremor data, but an accurate quantification of bedrock Vs is unattainable because of low spectral coherency at frequencies below 3 Hz. HVSR data corroborate the SPAC microtremor results at sites based on good alignment of theoretical Rayleigh ellipticity peaks, 1D SH amplifications, and peak HVSR. Resonant frequencies vary between 1.4 and 5.5 Hz between the sites from both observed HVSR and predicted 1D SH amplification. Shear-wave velocities to 30 m classify the sites as C, D, or E. This study demonstrates that given relatively shallow bedrock depth the SPAC method can work in extremely urbanized areas.

  3. Delineation of landform and lithologic units for Ecological Landtype-Association analysis in Glacier Bay National Park, Southeast Alaska

    Science.gov (United States)

    Brew, David A.

    2008-01-01

    Landform and generalized bedrock lithologic units have been delineated for ecological landtype association analysis in Glacier Bay National Park in southeast Alaska (as the Park boundaries were defined before the 1971 Alaska National Interest Lands expansion).

  4. Generalized Geology of Australia and New Zealand (geo3cl)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This coverage includes arcs, polygons, and polygon labels that describe the generalized geologic age and rock type of surface outcrops of bedrock of the Australia...

  5. Uranium Mill Tailings Remedial Action Project (UMTRAP), Slick Rock, Colorado, Revision 1. Volume 1, Calculations, Final design for construction

    International Nuclear Information System (INIS)

    Volume one contains calculations for: embankment design--embankment material properties; Union Carbide site--bedrock contours; vicinity properties--origin of contamination; North Continent and Union Carbide sites contaminated materials--excavation quantities; and demolition debris--quantity estimate

  6. Generalized Geology of the Former Soviet Union (geo1ec)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The data set outlines and describes the general geologic age and type of bedrock of the Former Soviet Union and selected adjacent areas. It also includes shoreline...

  7. San Diego Region Nearshore Coastal Zone Seafloor Substrate

    Data.gov (United States)

    California Department of Resources — The layer is meant to display those locations offshore where bedrock is present, as these locations may support sensitive habitats that could be adversely affected...

  8. Superfund GIS - Regolith thickness in Tennessee

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is a representation of the depth in feet to bedrock as reported in the driller's log for the Water Wells Database of the Tennessee Department of...

  9. Mars Landing + 50 Years: Repurposing the First Viking Landing Site on Chryse Planitia as an Exploration Zone for Automated Infrastructure Construction

    Science.gov (United States)

    Farrell, K. W.

    2015-10-01

    The proposed Chryse Planitia EZ centered near the VL-1 landing site has evidence for adequate water ice, silica, and load-bearing bedrock surface resources to utilize as infrastructure for long-term missions to support humans.

  10. Surface Geology of the Caribbean Region (geo6bg)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset includes polygons that describe the geologic age of surface outcrops of bedrock of the Caribbean region (Anguilla, Antigua and Barbuda, Aruba, Bahamas,...

  11. Surficial geology of Iran (geo2cg)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The geology data set for this map includes arcs, polygons, and labels that outline and describe the general geologic age and type of bedrock of Iran. The geologic...

  12. Surface Geology of Bangladesh (geo8bg)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This coverage includes arcs, polygons, and polygon labels that describe the geologic age and type of surface outcrops of bedrock of the Bangladesh. It also includes...

  13. Generalized Geology of the Far East (geo3al)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This coverage includes arcs, polygons, and polygon labels that describe the generalized geologic age and type of surface outcrops of bedrock of the Far East (China,...

  14. Major faults in Iran (flt2cg)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The geology data set for this map includes arcs, polygons, and labels that outline and describe the general geologic age and type of bedrock of Iran. The geologic...

  15. Map Service Showing Geology, Oil and Gas Fields, and Geological Provinces of Iran

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The geology data set for this map includes arcs, polygons, and labels that outline and describe the general geologic age and type of bedrock of Iran. The geologic...

  16. Generalized Geology of Southeast Asia (geo3bl)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This coverage includes arcs, polygons, and polygon labels that describe the generalized geologic age and type of surface outcrops of bedrock of Southeast Asia...

  17. Selected geologic data for wells and test holes in and near the Lost Creek Designated Ground Water Basin, Weld, Adams, and Arapahoe Counties, Colorado

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This point dataset contains geologic information concerning regolith thickness and top-of-bedrock altitude at selected well and test-hole locations in and near the...

  18. Contours of regolith thickness for the Lost Creek Designated Ground Water Basin, Weld, Adams, and Arapahoe Counties, Colorado

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset consists of contours showing generalized lines of equal regolith (unconsolidated sediment) thickness overlying bedrock in the Lost Creek Designated...

  19. Raster-based regolith thickness of the Lost Creek Designated Ground Water Basin, Weld, Adams, and Arapahoe Counties, Colorado

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset consists of raster-based generalized thickness of regolith (unconsolidated sediments) overlying bedrock in the Lost Creek Designated Ground Water...

  20. Generalized Geology of Europe including Turkey (geo4_2l)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This coverage includes arcs, polygons, and polygon labels that describe the generalized geologic age of surface outcrops of bedrock of Europe including Turkey...