WorldWideScience

Sample records for granitic crystalline rocks

  1. Natural analogue studies in crystalline rock: the influence of water-bearing fractures on radionuclide immobilisation in a granitic rock repository

    Alexander, W.R.; MacKenzie, A.B.; Scott, R.D.; McKinley, I.G.

    1990-06-01

    Current Swiss concepts for the disposal of radioactive waste involve disposal in deep mined repositories to ensure that only insignificant quantities of radionuclides will ever reach the surface and so enter the biosphere. The rock formations presently considered as potential candidates for hosting radwaste repositories have thus been selected on the basis of their capacity to isolate radionuclides from the biosphere. An important factor in ensuring such containment is a very low solute transport rate through the host formation. However, it is considered likely that, in the formations of interest in the Swiss programme (eg. granites, argillaceous sediments, anhydrite), the rocks will be fractured to some extent even at repository depth. In the instance of the cumulative failure of near-field barriers in the repository, these hydraulically connected fractures in the host formation could be very important far-field routes of migration (and possible sites of retardation) of radionuclides dissolved in the groundwaters. In this context, the so-called 'matrix diffusion' mechanism is potentially very important for radionuclide retardation. This report is the culmination of a programme which has attempted to assess the potential influence of these water-bearing fractures on radionuclide transport in a crystalline rock radwaste repository. 162 refs., 36 figs., 16 tabs

  2. Heat production in granitic rocks

    Artemieva, Irina; Thybo, Hans; Jakobsen, Kiki

    2017-01-01

    Granitic rocks play special role in the dynamics and evolution of the Earth and its thermal regime. First, their compositional variability, reflected in the distribution of concentrations of radiogenic elements, provides constraints on global differentiation processes and large scale planetary...... evolution, where emplacement of granites is considered a particularly important process for the formation of continental crust. Second, heat production by radioactive decay is among the main heat sources in the Earth. Therefore knowledge of heat production in granitic rocks is pivotal for thermal modelling...... of the continental lithosphere, given that most radiogenic elements are concentrated in granitic rocks of the upper continental crust whereas heat production in rocks of the lower crust and lithospheric mantle is negligible. We present and analyze a new global database GRANITE2017 (with about 500 entries...

  3. Uranium deposits in granitic rocks

    Nishimori, R.K.; Ragland, P.C.; Rogers, J.J.W.; Greenberg, J.K.

    1977-01-01

    This report is a review of published data bearing on the geology and origin of uranium deposits in granitic, pegmatitic and migmatitic rocks with the aim of assisting in the development of predictive criteria for the search for similar deposits in the U.S. Efforts were concentrated on the so-called ''porphyry'' uranium deposits. Two types of uranium deposits are primarily considered: deposits in pegmatites and alaskites in gneiss terrains, and disseminations of uranium in high-level granites. In Chapter 1 of this report, the general data on the distribution of uranium in igneous and metamorphic rocks are reviewed. Chapter 2 contains some comments on the classification of uranium deposits associated with igneous rocks and a summary of the main features of the geology of uranium deposits in granites. General concepts of the behavior of uranium in granites during crustal evolution are reviewed in Chapter 3. Also included is a discussion of the relationship of uranium mineralization in granites to the general evolution of mobile belts, plus the influence of magmatic and post-magmatic processes on the distribution of uranium in igneous rocks and related ore deposits. Chapter 4 relates the results of experimental studies on the crystallization of granites to some of the geologic features of uranium deposits in pegmatites and alaskites in high-grade metamorphic terrains. Potential or favorable areas for igneous uranium deposits in the U.S.A. are delineated in Chapter 5. Data on the geology of specific uranium deposits in granitic rocks are contained in Appendix 1. A compilation of igneous rock formations containing greater than 10 ppM uranium is included in Appendix 2. Appendix 3 is a report on the results of a visit to the Roessing area. Appendix 4 is a report on a field excursion to eastern Canada

  4. Radon exhalation from granitic rocks

    Del Claro, Flávia; Paschuk, Sergei A.; Corrêa, Janine N.; Mazer, Wellington; Narloch, Danielle Cristine; Martin, Aline Cristina; Denyak, Valeriy

    2017-01-01

    Naturally occurring radionuclides such as radon ( 222 Rn), its decay products and other elements from the radioactive series of uranium ( 238 U and 235 U) and thorium ( 232 Th) are an important source of human exposure to natural radioactivity. The worldwide evaluation of health radiobiological effects and risks from population exposure to natural radionuclides is a growing concern. About 50% of personal radiation annual dose is related to radionuclides such as radon ( 222 Rn), thoron ( 220 Rn), radium ( 226 Ra), thorium ( 232 Th) and potassium ( 40 K), which are present in modern materials commonly used in construction of dwellings and buildings. The radioactivity of marbles and granites is of big concern since under certain conditions the radioactivity levels of these materials can be hazardous to the population and require the implementation of mitigation procedures. Present survey of the 222 Rn and 220 Rn activity concentration liberated in the air was performed using commercialized Brazilian granite rocks at national market as well as exported to other countries. The 222 Rn and 220 Rn measurements were performed using the AlphaGUARD instant monitor and RAD7 detector, respectively. This study was performed at the Applied Nuclear Physics Laboratory of the Federal University of Technology – Paraná (UTFPR). Obtained results of radon concentration activity in air exhaled studied samples of granites varied from 3±1 Bq/m 3 to 2087±19 Bq/m 3 , which shows that some samples of granitic rocks represent rather elevated health risk the population. (author)

  5. Thermal expansion of granite rocks

    Stephansson, O.

    1978-04-01

    The thermal expansion of rocks is strongly controlled by the thermal expansion of the minerals. The theoretical thermal expansion of the Stripa Granite is gound to be 21 . 10 -6 [deg C] -1 at 25 deg C and 38 . 10 -6 [deg C] -1 at 400 deg C. The difference in expansion for the rock forming minerals causes micro cracking at heating. The expansion due to micro cracks is found to be of the same order as the mineral expansion. Most of the micro cracks will close at pressures of the order of 10 - 20 MPa. The thermal expansion of a rock mass including the effect of joints is determined in the pilot heater test in the Stripa Mine

  6. Radon exhalation from granitic rocks

    Del Claro, Flávia; Paschuk, Sergei A.; Corrêa, Janine N.; Mazer, Wellington; Narloch, Danielle Cristine; Martin, Aline Cristina [Universidade Tecnológica Federal do Paraná (UTFPR), Curitiba, PR (Brazil); Denyak, Valeriy, E-mail: flaviadelclaro@gmail.com, E-mail: spaschuk@gmail.com, E-mail: janine_nicolosi@hotmail.com, E-mail: denyak@gmail.com [Instituto de Pesquisa Pelé Pequeno Príncipe (IPPP), Curitiba, PR (Brazil)

    2017-07-01

    Naturally occurring radionuclides such as radon ({sup 222}Rn), its decay products and other elements from the radioactive series of uranium ({sup 238}U and {sup 235}U) and thorium ({sup 232}Th) are an important source of human exposure to natural radioactivity. The worldwide evaluation of health radiobiological effects and risks from population exposure to natural radionuclides is a growing concern. About 50% of personal radiation annual dose is related to radionuclides such as radon ({sup 222}Rn), thoron ({sup 220}Rn), radium ({sup 226}Ra), thorium ({sup 232}Th) and potassium ({sup 40}K), which are present in modern materials commonly used in construction of dwellings and buildings. The radioactivity of marbles and granites is of big concern since under certain conditions the radioactivity levels of these materials can be hazardous to the population and require the implementation of mitigation procedures. Present survey of the {sup 222}Rn and {sup 220}Rn activity concentration liberated in the air was performed using commercialized Brazilian granite rocks at national market as well as exported to other countries. The {sup 222}Rn and {sup 220}Rn measurements were performed using the AlphaGUARD instant monitor and RAD7 detector, respectively. This study was performed at the Applied Nuclear Physics Laboratory of the Federal University of Technology – Paraná (UTFPR). Obtained results of radon concentration activity in air exhaled studied samples of granites varied from 3±1 Bq/m{sup 3} to 2087±19 Bq/m{sup 3}, which shows that some samples of granitic rocks represent rather elevated health risk the population. (author)

  7. Redox front penetration in the fractured Toki Granite, central Japan: An analogue for redox reactions and redox buffering in fractured crystalline host rocks for repositories of long-lived radioactive waste

    Yamamoto, Koshi; Yoshida, Hidekazu; Akagawa, Fuminori; Nishimoto, Shoji; Metcalfe, Richard

    2013-01-01

    Highlights: • Deep redox front developed in orogenic granitic rock have been studied. • The process was controlled by the buffering capacity of minerals. • This is an analogue of redox front penetration into HLW repositories in Japan. - Abstract: Redox buffering is one important factor to be considered when assessing the barrier function of potential host rocks for a deep geological repository for long-lived radioactive waste. If such a repository is to be sited in fractured crystalline host rock it must be demonstrated that waste will be emplaced deeper than the maximum depth to which oxidizing waters can penetrate from the earth’s surface via fractures, during the assessment timeframe (typically 1 Ma). An analogue for penetration of such oxidizing water occurs in the Cretaceous Toki Granite of central Japan. Here, a deep redox front is developed along water-conducting fractures at a depth of 210 m below the ground surface. Detailed petrographical studies and geochemical analyses were carried out on drill core specimens of this redox front. The aim was to determine the buffering processes and behavior of major and minor elements, including rare earth elements (REEs), during redox front development. The results are compared with analytical data from an oxidized zone found along shallow fractures (up to 20 m from the surface) in the same granitic rock, in order to understand differences in elemental migration according to the depth below the ground surface of redox-front formation. Geochemical analyses by XRF and ICP-MS of the oxidized zone at 210 m depth reveal clear changes in Fe(III)/Fe(II) ratios and Ca depletion across the front, while Fe concentrations vary little. In contrast, the redox front identified along shallow fractures shows strong enrichments of Fe, Mn and trace elements in the oxidized zone compared with the fresh rock matrix. The difference can be ascribed to the changing Eh and pH of groundwater as it flows downwards in the granite, due to

  8. Deep fracturation of granitic rock mass

    Bles, J.L.; Blanchin, R.; Bonijoly, D.; Dutartre, P.; Feybesse, J.L.; Gros, Y.; Landry, J.; Martin, P.

    1986-01-01

    This documentary study realized with the financial support of the European Communities and the CEA aims at the utilization of available data for the understanding of the evolution of natural fractures in granitic rocks from the surface to deep underground, in various feasibility studies dealing with radioactive wastes disposal. The Mont Blanc road tunnel, the EDF Arc-Isere gallerie, the Auriat deep borehole and the Pyrenean rock mass of Bassies are studied. In this study are more particularly analyzed the relationship between small fractures and large faults, evolution with depth of fracture density and direction, consequences of rock decompression and relationship between fracturation and groundwater [fr

  9. Geochemistry and petrogenesis of Proterozoic granitic rocks from ...

    Geochemistry and petrogenesis of Proterozoic granitic ... This study presents the geochemical characteristics of granitic rocks located on the northern ... Frost and Frost 2013). ...... King P L, White A J R, Chappell B W and Allen C M 1997.

  10. The effects of bacteria on crystalline rock

    Brown, D.A.

    1994-01-01

    Many reactions involving inorganic minerals at water-rock interfaces have now been recognized to be bacterially mediated; these reactions could have a significant effect in the excavation of vaults for toxic and radioactive waste disposal. To investigate the role that bacteria play in the natural aqueous environment of crystalline rock the microbial growth factors of nutrition, energy and environment are described. Microbial activity has been investigated in Atomic Energy of Canada's Underground Research Laboratory (URL), situated in the Archean granitic Lac du Bonnet Batholith, Winnipeg, Manitoba. Faults, initiated in the Early Proterozoic, and later-formed fractures, provide ground-water pathways. Planktonic bacteria, free-swimming in the groundwater, have been observed in over 100 underground borehole samples. The number of bacteria varied from 10 3 to 10 5 mL -1 and appeared to decrease with depth and with increased salinity of the water. However, in the natural environment of deep (100-500 m) crystalline rocks, where nutrition is limited, formation of biofilms by sessile bacteria is a successful survival strategy. Natural biofilms at the URL and biofilms grown in bioreactors have been studied. The biofilms can accumulate different elements, depending upon the local environment. Precipitates of iron have been found in all the biofilms studied, where they are either passively accumulated or utilized as an energy source. Within the biofilm active and extensive biogeochemical immobilization of dissolved elements is controlled by distinct bacterial activities which are sufficiently discrete for hematite and siderite to be precipitated in close proximity

  11. Sorption of actinides in granitic rock

    Allard, B

    1982-11-01

    The sorption of americium (III), neptunium(V) and plutonium on geologic media under oxic conditions has been measured by a batch technique. The aqueous phase was a synthetic groundwater or 4M NaCl solution. The solid phase was a pure mineral, representative of igneous rocks, or granite. Altogether 40 different minerals and rocks were used. The effects of pH and the ionic strength of the aqueous phase as well as of the cation exchange capacity and the surface/mass ratio of the solid sorbent are discussed. Empirical equations giving the distribution coefficient as a function of pH in the environmental pH-range 7-9 are suggested. Some observations and conclusions concerning sorption mechanisms are given. (author)

  12. Example of fracture characterization in granitic rock

    Thorpe, R.K.

    1981-03-01

    A detailed study of geologic discontinuities for an underground heater test in highly fractured granitic rock is reported. Several prominent shear fractures were delineated within a 6 x 30 x 15 m rock mass by correlating surface mapping and borehole fracture logs. Oblique-reverse faulting is suspected on at least one of the surfaces, and its inferred borehole intercepts appear to be collinear in the direction of slickensiding observed in the field. Four distinct joint sets were identified, one of which coincides with the shear fractures. Another lies nearly horizontal, and two others are steeply inclined and orthogonal. Fracture lengths and spacings for the four joint sets are represented by lognormal probability distributions

  13. The source rock characters of U-rich granite

    Mingyue, Feng; Debao, He [CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technology, Beijing Research Institute of Uranium Geology (China)

    2012-03-15

    This paper discusses the stratum composition, lithological association, uranium content of crust and the activation, migration, concentration of uranium at each tectonic cycle in South China. The authors point out that the source rock of U-rich granite is U-rich continental crust which is rich in Si, Al and K. The lithological association is mainly composed of terrestrial clastic rocks formation of mudstone and sandstone, mingled with intermediate-acidic, mafic pyroclastic rocks and carbonate rocks formation. During tectonic movements, the rocks had undergone regional metamorphism, migmatitization, granitization, and formed U-rich granites finally. (authors)

  14. The source rock characters of U-rich granite

    Feng Mingyue; He Debao

    2012-01-01

    This paper discusses the stratum composition, lithological association, uranium content of crust and the activation, migration, concentration of uranium at each tectonic cycle in South China. The authors point out that the source rock of U-rich granite is U-rich continental crust which is rich in Si, Al and K. The lithological association is mainly composed of terrestrial clastic rocks formation of mudstone and sandstone, mingled with intermediate-acidic, mafic pyroclastic rocks and carbonate rocks formation. During tectonic movements, the rocks had undergone regional metamorphism, migmatitization, granitization, and formed U-rich granites finally. (authors)

  15. Aqueous phase transport through granitic rocks

    Bradbury, M.H.; Green, A.

    1984-03-01

    Using Scottish granites of UK origin it has been established that : (1) pore connectivity exists over metre distances and does not vary significantly with distance. (2) The formation factor may show an increase by a factor of approx. 2 for thin samples (approx. 1 cm). Since diffusion samples are of this order of thickness, laboratory measurements may be overestimating the diffusion coefficient appropriate for use in migration model calculations by a factor of approx. 2. (3) The effect of confining pressures up to approx. 16 MPa is to reduce diffusion coefficients by 50 to 60%. This implies that diffusion coefficients appropriate to granite at depths of approx. 500 m are approximately a factor of two lower than those obtained in the laboratory. (4) Diffusion rates through weathered fissure surfaces can be significantly greater (up to approx. 200 times) than through 'good' rock and are strongly dependent on the severity of the weathering. No evidence for pore blocking by weathering products was found. (5) Latex colloids having a diameter of 0.312 μm neither cause pore blocking nor do they penetrate the pore structure. (author)

  16. Granitic rocks from the southern Gyeongsang basin, southeastern Korea, (1)

    Lee, Yoon-Jong

    1980-01-01

    In southern Gyeongsang basin, southeastern Korea, there are many granitic rock masses. They were divided into 7 groups according to their geological evidences. K-Ar age was determined on 36 samples obtained from the respective groups. Group A: pre-Gyeongsang granitic rock (Pre-Cretaceous), A 1 220 m.y., A 2 166 m.y.; group B: outer zone granitic rock (Cretaceous), 115-72 m.y.; group C: ditto (ditto), 97-70 m.y.; group D: ditto (ditto), 89-68 m.y.; group E: ditto (ditto), 82-68 m.y.; group F: inner zone granitic rock (Cretaceous), 75-74 m.y.; group G: Tertiary granitic rock, 63-41 m.y. The large part of the Cretaceous granitic masses show the double elongated ring form. Most of the Tertiary granitic rocks were probably emplaced in close relation with the Eonyang fault line and Ulsan fault line/or their extension line of the area. (J.P.N.)

  17. Mechanical properties of granitic rocks from Gideaa, Sweden

    Ljunggren, C.; Stephansson, O.; Alm, O.; Hakami, H.; Mattila, U.

    1985-10-01

    The elastic and mechanical properties were determined for two rock types from the Gideaa study area. Gideaa is located approximately 30 km north-east of Oernskoeldsvik, Northern Sweden. The rock types that were tested were migmatitic gneiss and migmatitic granite. The following tests were conducted: - sound velocity measurements; - uniaxial compression tests with acoustic emission recording; - brazilian disc tests; - triaxial tests; - three point bending tests. All together, 12 rock samples were tested with each test method. Six samples of these were migmatic gneiss and six samples were migmatitic granite. The result shows that the migmatitic gneiss has varying strength properties with low compressive strength in comparison with its high tensile strength. The migmatitic granite, on the other hand, is found to have parameter values similar to other granitic rocks. With 15 refs. (Author)

  18. Hydraulic testing in crystalline rock

    Almen, K.E.; Andersson, J.E.; Carlsson, L.; Hansson, K.; Larsson, N.A.

    1986-12-01

    Swedish Geolocical Company (SGAB) conducted and carried out single-hole hydraulic testing in borehole Fi 6 in the Finnsjoen area of central Sweden. The purpose was to make a comprehensive evaluation of different methods applicable in crystalline rocks and to recommend methods for use in current and scheduled investigations in a range of low hydraulic conductivity rocks. A total of eight different methods of testing were compared using the same equipment. This equipment was thoroughly tested as regards the elasticity of the packers and change in volume of the test section. The use of a hydraulically operated down-hole valve enabled all the tests to be conducted. Twelve different 3-m long sections were tested. The hydraulic conductivity calculated ranged from about 5x10 -14 m/s to 1x10 -6 m/s. The methods used were water injection under constant head and then at a constant rate-of-flow, each of which was followed by a pressure fall-off period. Water loss, pressure pulse, slug and drill stem tests were also performed. Interpretation was carried out using standard transient evaluation methods for flow in porous media. The methods used showed themselves to be best suited to specific conductivity ranges. Among the less time-consuming methods, water loss, slug and drill stem tests usually gave somewhat higher hydraulic conductivity values but still comparable to those obtained using the more time-consuming tests. These latter tests, however, provided supplementary information on hydraulic and physical properties and flow conditions, together with hydraulic conductivity values representing a larger volume of rock. (orig./HP)

  19. Hydrothermal alteration of Hercynian granites, its significance to the evolution of geothermal systems in granitic rocks

    Marques, Jose M.; Matias, Maria J.; Basto, Maria J.; Aires-Barros, Luis A. [Instituto Superior Tecnico, Centro de Petrologia e Geoquimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Carreira, Paula M. [Instituto Tecnologico e Nuclear, Estrada Nacional n 10, 2686 - 953 Sacavem (Portugal); Goff, Fraser E. [Earth and Planetary Sciences Department, Univ. of New Mexico, Albuquerque, NM 87131 (United States)

    2010-06-15

    We discuss geochemical and isotopic ({sup 18}O/{sup 16}O, {sup 2}H/{sup 1}H and {sup 87}Sr/{sup 86}Sr) data recording the hydrothermal alteration of northern Portuguese Hercynian granites by Na-HCO{sub 3}-CO{sub 2}-rich mineral waters. Whole-rock samples from drill cores of Vilarelho da Raia granite have {delta}{sup 18}O values in the +11.47 to +10.10 permille range. The lower values correspond to highly fractured granite samples displaying vein and pervasive alteration. In the pervasive alteration stage, which probably results from a convective hydrothermal system set up by the intrusion of the granites, the metamorphic waters are in equilibrium with hydrous minerals. In contrast, the vein alteration of these granitic rocks was caused by water of meteoric origin. The oxygen ratios between water (W) and rock (R), the so-called W/R ratios, obtained for the open system (where the heated water is lost from the system by escape to the surface) range between 0.05 and 0.11, suggesting that the recrystallization of the veins was influenced by a small flux of meteoric water. Stable isotope analyses performed on the cores show that the vein alteration stage relates to post-emplacement tectonic stresses acting on the granite, probably of late Hercynian age. Our results are consistent with the existence of two separate alteration events (pervasive and vein) caused by hydrothermal waters of different isotopic characteristics. The studies presented in this paper should be viewed as a natural analogue that uses the alteration features observed in a fossil geothermal system at Vilarelho da Raia to assess possible water-rock reactions presently occurring at depth in granitic rocks of the nearby Chaves area. (author)

  20. Mechanical dispersion in fractured crystalline rock systems

    Lafleur, D.W.; Raven, K.G.

    1986-12-01

    This report compiles and evaluates the hydrogeologic parameters describing the flow of groundwater and transport of solutes in fractured crystalline rocks. This report describes the processes of mechanical dispersion in fractured crystalline rocks, and compiles and evaluates the dispersion parameters determined from both laboratory and field tracer experiments. The compiled data show that extrapolation of the reliable test results performed over intermediate scales (10's of m and 10's to 100's of hours) to larger spatial and temporal scales required for performance assessment of a nuclear waste repository in crystalline rock is not justified. The reliable measures of longitudinal dispersivity of fractured crystalline rock are found to range between 0.4 and 7.8 m

  1. Diffusion in the matrix of granitic rock

    Birgersson, L.; Neretnieks, I.

    1982-07-01

    A migration experiment in the rock matrix is presented. The experiment has been carried out in undisturbed rock, that is rock under its natural stress environment. Since the experiment was performed at the 360 m-level (in the Stripa mine), the rock had nearly the same conditions as the rock surrounding a nuclear waste storage. The results show that all three tracers (Uranine, Cr-EDTA and I - ) have passed the disturbed zone from the injection hole and migrated into undisturbed rock. At the distance of 11 cm from the injection hole 5-10 percent of the injection concentration was found. The results also indicate that the tracer have passed through fissure filling material. These results indicate that it is possible for tracers (and therefore radionuclides) to migrate from a fissure, through fissure filling material, and into the undisturbed rock matrix. (Authors)

  2. Characteristics of micro transfer paths and diffusion phenomena in the matrix of deep crystalline rock

    Ishibashi, Masayuki; Sasao, Eiji; Hama, Katsuhiro

    2016-01-01

    Matrix diffusion is one of the important phenomena for evaluating the safety of the geological disposal of high level waste because it has an effect of retarding mass transport in crystalline rocks. Previous studies indicated that the altered granitic rocks have high retardation functions due to the micropore formation associated with hydrothermal alteration; however, there has not been enough knowledge on the matrix diffusion in weakly unaltered rocks (macroscopically unaltered rocks). Since the macroscopically altered granitic rocks in Japan are likely to be affected by deuteric alteration due to hydrothermal flu resulting from crystallization of granitic magma, it is important to understand the effect of deuteric alteration on the matrix diffusion. Therefore, detailed observations were carried out to clarify the effects of deuteric alteration focused on the macroscopically unaltered granite sampled from 300 m and 500 m below ground levels at the Mizunami Underground Research Laboratory, central Japan. The results provide that the micropores are selectively formed in plagioclases due to deuteric alteration and they have the potential of acting as matrix diffusion paths. This is indicating the possibility that deuteric alteration can retard the mass transport in crystalline rocks in Japan. That plays a significant role in enforcing the barrier function of crystalline rocks. (author)

  3. The Landforms of Granitic Rocks: An Annotated Bibliography

    1990-05-01

    vertical joints are dominant. Duricrust and rock basins are common. The latter are independent of jointing and are associated with the older, thicker... duricrust . 15 Davis, W. M. 1933. Granitic domes of the Mohave Desert, California. Transactions of the San Diego Society of Natural History, vol. 7, pp

  4. Chemical Variations in a Granitic Pluton and Its Surrounding Rocks.

    Baird, A K; McIntyre, D B; Welday, E E; Madlem, K W

    1964-10-09

    New techniques of x-ray fluorescence spectrography have provided, for the first time, abundant data regarding chemical variability of granitic rocks on different scales. The results suggest that current designs of sampling plans for trend surface analysis should be modified; in particular several specimens, preferably drillcores, may be required at each locality.

  5. Oxygen and hydrogen isotope studies of plutonic granitic rocks

    Taylor, H.P. Jr.

    1978-01-01

    The primary deltaD values of the biotites and hornblendes in granitic batholiths are remarkably constant at about -50 to -85, identical to the values in regional metamorphic rocks, marine sediments and greenstones, and most weathering products in temperate climates. Therefore the primary water in these igneous rocks is probably not 'juvenile', but is ultimately derived by dehydration and/or partial melting of the lower crust or subducted lithosphere. Most granitic rocks have delta 18 O = +7.0 to +10.0, probably indicating significant involvment of high- 18 O metasedimentary or altered volcanic rocks in the melting process; such an origin is demanded for many other granodiorites and tonalites that have delta 18 O = +10 to +13. Gigantic meteoric-hydrothermal convective circulation systems were established in the epizonal portions of all batholiths, locally producing very low delta 18 O values (particularly in feldspars) during subsolidus exchange. Some granitic plutons in such environments also were emplaced as low- 18 O magmas probably formed by melting or assimilation of hydrothermally altered roof rocks. However, the water/rock ratios were typically low enough that over wide areas the only evidence for meteoric water exchange in the batholiths is given by low D/H ratios (deltaK as low as -180); for example, because of latitudinal isotopic variations in meteoric waters, as one moves north through the Cordilleran batholiths of western North America an increasingly higher proportion of the granitic rocks have deltaD values lower than -120. The lowering of deltaD values commonly corelates with re-setting of K-Ar ages. (Auth.)

  6. Study of deep fracturation of granitic rock mass. Documentary study

    Bles, J.L.; Landry, J.

    1984-01-01

    This documentary study realized with the financial support of the European Communities and the CEA aims at the utilization of available data for the understanding of the evolution of natural fractures in granitic rocks from the surface to deep underground. The Mt Blanc road tunnel, the EDF's Arc-Isere gallerie, the Auriat deep borehole and the Pyrenean rock mass of Bassies are studied because detailed structural and geological studies have been realized these last 20 years. In this study are more particularly analyzed the relationship between small fractures and large faults, evolution with depth of fracture density and direction, consequences of rock decompression and relationship between fracturation and groundwater

  7. Chemical alteration of a granitic rock

    Charles, R.W.

    1977-01-01

    A study of reaction of a well characterized biotite granodiorite with initially distilled water at 300 0 C and 1/3 kb for 8 months has produced many morphological and chemical effects. Solution samples were taken at 1 day, 2 days, 1 week, 2 weeks, 1 month, 2 months, 4 months, and 8 months. Rock samples were removed after 1 month, 2 months, 4 months, and 8 months. Eight polished rock disks were mounted on a tantalum pedestal inside a 500 ml autoclave. The autoclave is part of a circulation system designed for operation at T and P of 500 0 C and 1/3 kb. The starting granodiorite consisted of quartz (23 percent), microcline (20 percent, Or/sub 94 +- 2/-Ab/sub 6 +- 1/An/sub 0 + 1/), plagioclase (37 percent, core Or/sub 2 +- 1/Ab/sub 73 +- 2/An/sub 25 +- 1/, rim Or/sub 2 +- 1/Ab/sub 88 +- 5/An/sub 10 +- 5/), chloritized biotite (13 percent), epidote (2 percent), sphene (2 percent), apatite (1 percent) and opaques (2 percent). The reactivity of phases as shown by scanning electron microscope are: quartz much greater than microcline greater than plagioclase greater than mafics, opaques, and apatite. Major phase morphology and composition are monitored throughout the experiment by scanning electron microscopy and electron microprobe analysis. After 8 months, quartz showed etching several mm in depth. Plagioclase became much more calcic with time. Plagioclase changed from oligoclase (fresh) to andesine (1 month) to labradorite (2 months) to bytownite (4 months). Microcline showed almost congruent dissolution. Analyses from the most reacted disks indicate the presence of a possibly amorphous alumina rich phase on a microcline substrate. Biotite and the other phases were essentially inert. Three secondary overgrowths were observed: vermiculite, growing on the mafic phases and two zeolites, thomsonite and ashcroftine, growing on the plagioclase feldspars

  8. Radionuclide sorption on crushed and intact granitic rock

    Eriksen, Tryggve E.; Locklund, Birgitta

    1989-05-01

    The specific surface areas and distribution ratios for sorption of 85 Sr, 137 Cs and 152 Eu were measured for crushed and intact granite rock. The experimental data can be accommodated by a sorption model encompassing sorption on outer and inner surface. It is clearly demonstrated that the time required to obtain reliable Kd-values for the sorption of strongly sorbing radionuclides like 152 Eu is very long due to solution depletion and slow diffusion into the rock. A combination of surface area measurements and batch sorption with small particles may therefore be preferable when studying strongly sorbing nuclides. (authors) (17 figs., 6 tabs.)

  9. Abiogenic methanogenesis in crystalline rocks

    Lollar, B.S.; Frape, S.K. (Univ. of Waterloo, Ontario (Canada)); Weise, S.M. (Institut fuer Hydrologie (G.S.F), Neuherberg (Germany)); Fritz, P. (UFZ, Umweltforschungszentrum, Leipzig-Halle (Germany)); Macko, S.A. (Univ. of Virginia, Charlottesville, VA (United States)); Welhan, J.A. (Idaho State Univ., Pacatello, ID (United States))

    1993-12-01

    Isotopically anomalous CH[sub 4]-rich gas deposits are found in mining sites on both the Canadian and Fennoscandian shields. With [delta][sup 13]C[sub CH4] values from -22.4 to -48.5% and [delta]D[sub CH4] values from -133 to -372%, these methane deposits cannot be accounted for by conventional processes for bacterial or thermogenic methanogenesis. Compositionally the gases are similar to other CH[sub 4]-rich gas occurrences found in Canadian and Fennoscandian shield rocks. However, the isotopically anomalous gases of this study are characterized by unexpectedly high concentrations of H[sub 2] gas, ranging from several volume percent up to 30 vol%. The H[sub 2] gases are consistently depleted in the heavy isotope, with [delta]D[sub H[sub 2

  10. Fracture detection in crystalline rock using ultrasonic shear waves

    Waters, K.H.; Palmer, S.P.; Farrell, W.E.

    1978-12-01

    An ultrasonic shear wave reflection profiling system for use in the detection of water-filled cracks occurring within a crystalline rock mass is being tested in a laboratory environment. Experiments were performed on an irregular tensile crack induced approximately 0.5 m below one circular face of a 1.0-m-dia, 1.8-m-long granite cylinder. Good reflection data were obtained from this irregular crack with the crack either air filled or water filled. Data were collected that suggest a frequency-dependent S/sub H/ wave reflection coefficient for a granite-water interface. Waves that propagate along the free surface of a rock mass (surface waves) can severely hinder the detection of reflected events. Two methods of reducing this surface wave noise were investigated. The first technique uses physical obstructions (such as a slit trench) to scatter the surface waves. The second technique uses a linear array of receivers located on the free surface to cancel waves that are propagating parallel to the array (e.g., surface waves), thus enhancing waves with propagation vectors orthogonal to the linear array (e.g., reflected events). Deconvolution processing was found to be another method useful in surface wave cancellation

  11. The origin of groundwater salinity in granitic rocks: identification and characterisation of chloride sources

    Savoye, Sebastien

    1998-01-01

    This research thesis aims at clearly identifying the possible origins of chlorine in solution in underground waters in a granitic environment, and is thus a first step in the prediction of concentration of dissolved compounds in waters in crystalline environment, with respect to the geological context. In a first part, the author proposes a synthetic and critical overview of knowledge and previous studies: definition of the term 'salinity', presentation of geochemical tracers, presentation of available data on potential chlorine sources in granitic rocks. The author then describes the experimental protocols and studied sites, reports results of the characterisation of different chlorine tanks performed on samples from each studied site. Based on mass assessment calculations and on the use of tracers, the author finally discusses the contribution of each of the chlorine tanks to the salinity of underground waters [fr

  12. Characterization of crystalline rocks in the Lake Superior region, USA: implications for nuclear waste isolation

    Sood, M.K.; Flower, M.F.J.; Edgar, D.E.

    1984-01-01

    The Lake Superior region (Wisconsin, the Upper Peninsula of Michigan, and Minnesota) contains 41 Precambrian crystalline rock complexes comprising 64 individual but related rock bodies with known surface exposures. Each complex has a map area greater than 78 km 2 . About 54% of the rock complexes have areas of up to 500 km 2 , 15% fall between 500 km 2 and 1000 km 2 , 19% lie between 1000 km 2 and 2500 km 2 , and 12% are over 2500 km 2 . Crystalline rocks of the region vary widely in composition, but they are predominantly granitic. Repeated thermo-tectonic events have produced early Archean gneisses, migmatites, and amphibolites with highly tectonized fabrics that impart a heterogeneous and anisotropic character to the rocks. Late Archean rocks are usually but not invariably gneissose and migmatitic. Proterozoic rocks of the region include synorogenic (foliated) granitic rocks, anorogenic (non-foliated) granites, and the layered gabbro-anorthosite-troctolite intrusives of the rift-related Keweenawan igneous activity. Compared with the Archean rocks of the region, the Proterozoic bodies generally lack highly tectonized fabrics and have more definable contacts where visible. Anorogenic intrusions are relatively homogeneous and isotropic. On the basis of observed geologic characteristics, postorogenic and anorogenic crystalline rock bodies located away from recognized tectonic systems have attributes that make them relatively more desirable as a possible site for a nuclear waste repository in the region. This study was conducted at Argonne National Laboratory under the sponsorship of the US Department of Energy through the Office of Crystalline Repository Development at Battelle Memorial Institute, Columbus, Ohio. 84 references, 4 figures, 3 tables

  13. Characterization of crystalline rocks in the Lake Superior region, USA: implications for nuclear waste isolation

    Sood, M.K.; Edgar, D.E.; Flower, M.F.J.

    1984-01-01

    The Lake Superior region (Wisconsin, the Upper Peninsula of Michigan, and Minnesota) contains 41 Precambrian crystalline (medium- to coarse-grained igneous and high-grade metamorphic) rock complexes comprising 64 individual but related rock bodies with known surface exposures. Each complex has a map area greater than 78 km 2 . About 54% of the rock complexes have areas of up to 500 km 2 , 15% fall between 500 km 2 and 1000 km 2 , 19% lie between 1000 km 2 and 2500 km 2 , and 12% are over 2500 km 2 . Crystalline rocks of the region vary widely in composition, but they are predominantly granitic. Repeated thermo-tectonic events have produced early Archean gneisses, migmatites, and amphibolites with highly tectonized fabrics that impart a heterogeneous and anisotropic character to the rocks. Late Archean rocks are usually but not invariably gneissose an migmatitic. Proterozoic rocks of the region include synorogenic (foliated) granitic rocks, anorogenic (nonfoliated) granites, and the layered gabbro-anorthosite-troctolite intrusives of the rift-related Keweenawan igneous activity. Compared with the Archean rocks of the region, the Proterozoic bodies generally lack highly tectonized fabrics and have more definable contacts where visible. Anorogenic intrusions are relatively homogeneous and isotropic. On the basis of observed geologic characteristics, postorogenic and anorogenic crystalline rock bodies located away from recognized tectonic systems have attributes that make them relatively more desirable as a possible site for a nuclear waste repository in the region. This study was conducted at Argonne National Laboratory under the sponsorship of the US Department of Energy through the Office of Crystalline Repository Development at Battelle Memorial Institute, Columbus, Ohio

  14. Used fuel disposition in crystalline rocks

    Wang, Y. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hadgu, Teklu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kalinina, Elena Arkadievna [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jerden, James L. [Argonne National Lab. (ANL), Argonne, IL (United States); Copple, Jacqueline M. [Argonne National Lab. (ANL), Argonne, IL (United States); Cruse, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Ebert, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Buck, E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Eittman, R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tinnacher, R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tournassat, Christophe. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Davis, J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Viswanathan, H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Joseph, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-09-01

    The U.S. Department of Energy Office of Nuclear Energy, Office of Fuel Cycle Technology established the Used Fuel Disposition Campaign (UFDC) in fiscal year 2010 (FY10) to conduct the research and development (R&D) activities related to storage, transportation and disposal of used nuclear fuel and high level nuclear waste. The objective of the Crystalline Disposal R&D Work Package is to advance our understanding of long-term disposal of used fuel in crystalline rocks and to develop necessary experimental and computational capabilities to evaluate various disposal concepts in such media.

  15. Inelastic deformations of fault and shear zones in granitic rock

    Wilder, D.G.

    1986-02-01

    Deformations during heating and cooling of three drifts in granitic rock were influenced by the presence of faults and shear zones. Thermal deformations were significantly larger in sheared and faulted zones than where the rock was jointed, but neither sheared nor faulted. Furthermore, thermal deformations in faulted or sheared rock were not significantly recovered during subsequent cooling, thus a permanent deformation remained. This inelastic response is in contrast with elastic behavior identified in unfaulted and unsheared rock segments. A companion paper indicates that deformations in unsheared or unfaulted rock were effectively modeled as an elastic response. We conclude that permanent deformations occurred in fractures with crushed minerals and fracture filling or gouge materials. Potential mechanisms for this permanent deformation are asperity readjustments during thermal deformations, micro-shearing, asperity crushing and crushing of the secondary fracture filling minerals. Additionally, modulus differences in sheared or faulted rock as compared to more intact rock would result in greater deformations in response to the same thermal loads

  16. Radionuclide migration in crystalline rock fractures

    Hoelttae, P.

    2002-01-01

    Crystalline rock has been considered as a host medium for the repository of high radioactive spent nuclear fuel in Finland. The geosphere will act as an ultimate barrier retarding the migration of radionuclides to the biosphere if they are released through the technical barriers. Radionuclide transport is assumed to take place along watercarrying fractures, and retardation will occur both in the fracture and within the rock matrix. To be able to predict the transport and retardation of radionuclides in rock fractures and rock matrices, it is essential to understand the different phenomena involved. Matrix diffusion has been indicated to be an important mechanism, which will retard the transport of radionuclides in rock fractures. Both dispersion and matrix diffusion are processes, which can have similar influences on solute breakthrough curves in fractured crystalline rock. In this work, the migration of radionuclides in crystalline rock fractures was studied by means of laboratory scale column methods. The purpose of the research was to gain a better understanding of various phenomena - particularly matrix diffusion - affecting the transport and retardation behaviour of radionuclides in fracture flow. Interaction between radionuclides and the rock matrix was measured in order to test the compatibility of experimental retardation parameters and transport models used in assessing the safety of underground repositories for spent nuclear fuel. Rock samples of mica gneiss and of unaltered, moderately altered and strongly altered tonalite represented different rock features and porosities offering the possibility to determine experimental boundary limit values for parameters describing both the transport and retardation of radionuclides and rock matrix properties. The dominant matrix diffusion behaviour was demonstrated in porous ceramic column and gas diffusion experiments. Demonstration of the effects of matrix diffusion in crystalline rock fracture succeeded for the

  17. Characterizing gas permeability and pore properties of Czech granitic rocks

    Konečný, Pavel; Kožušníková, Alena

    2016-01-01

    Roč. 13, č. 4 (2016), s. 331-338 ISSN 1214-9705 R&D Projects: GA ČR GA105/09/0089; GA MŠk(CZ) LO1406; GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : granitic rocks * permeability * pore properties Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.699, year: 2016 https://www.irsm.cas.cz/materialy/acta_content/2016_doi/Konecny_AGG_2016_0015.pdf

  18. Underground nuclear explosion effects in granite rock fracturing

    Derlich, S.

    1970-01-01

    On the Saharan nuclear test site in Hoggar granite, mechanical properties of the altered zones were studied by in situ and laboratory measurements. In situ methods of study are drillings, television, geophysical and permeability measurements. Fracturing is one of the most important nuclear explosion effects. Several altered zones were identified. There are: crushed zone, fractured zone and stressed zone. Collapse of crushed and fractured zone formed the chimney. The extent of each zone can be expressed in terms of yield and of characteristic parameters. Such results are of main interest for industrial uses of underground nuclear explosives in hard rock. (author)

  19. Underground nuclear explosion effects in granite rock fracturing

    Derlich, S [Commissariat a l' Energie Atomique, Centre d' Etude de Bruyeres-le-Chatel (France)

    1970-05-01

    On the Saharan nuclear test site in Hoggar granite, mechanical properties of the altered zones were studied by in situ and laboratory measurements. In situ methods of study are drillings, television, geophysical and permeability measurements. Fracturing is one of the most important nuclear explosion effects. Several altered zones were identified. There are: crushed zone, fractured zone and stressed zone. Collapse of crushed and fractured zone formed the chimney. The extent of each zone can be expressed in terms of yield and of characteristic parameters. Such results are of main interest for industrial uses of underground nuclear explosives in hard rock. (author)

  20. Waste disposal in granitic rocks: analysis of thermal microcracks

    Montoto, M.; Roeshoff, K.; Leojon, B.; Bel-Lan, A.

    1981-04-01

    The possible development of microcracks from a thermal origin has been researched in the granitic rocks of Shipa (Sweden), within which in a real scale have been originated some thermal gradients similar to the ones which could take place in the waste disposal. To achieve an optimal fratographic information, with some petrographic meaning, different microscopic techniques, optical and electronic, have been combined and an automatized quantification methodology has also been developed by means of digitals. Between warmed and unwarmed granitis no microfractographic differences have been detected. The observed variations are only apparent and may be explained as a function of the inherent petrographic heterogeneity of rocky blocks. In any case in the internal temperatures generated within these rocks have not attained its own threshold of thermal microcracking. (author)

  1. Geological site selection studies in Precambrian crystalline rocks in Finland

    Vuorela, P.

    1988-01-01

    In general geological investigations made since 1977 the Finnish crystalline bedrock has been determined to be suitable for the final disposal of the spent nuclear fuel. Regional investigations have been mainly based on already existing geological studies. Special attention has been paid on the international geological Finland as the Baltic Shield is stiff and stable and situated far outside the zones of volcanic and seismic activity. The present day crustal movements in Finland are related to landuplift process. Movements and possible faults in the bedrock follow fracture zones which devide the bedrock into mosaiclike blocks. As compared to small scale geological maps the bedrock blocks are often indicated as large granite rock formations which are less broken than the surrounding rocks, though the age of granite formations is at least 1500 millions of years. The large bedrock blocks (20-300 km 2 ) are divided to smaller units by different magnitudes of fractures and these smaller bedrock units (5-20 km 2 ) have been selected for further site selection investigations. At the first stage of investigations 327 suitable regional bedrock blocks have been identified on the basis of Landsat-1 winter and summer mosaics of Finland. After two years of investigations 134 investigation areas were selected inside 61 bedrock blocks and classified to four priority classes, the three first of which were redommended for further investigations. Geological criteries used in classification indicated clear differences between the classes one and three, however all classified areas are situated in large rather homogenous bedrock blocks and more exact three dimensional suitability errors may not be observed until deep bore holes have been made

  2. Hydrogeologic characterization of a fractured granitic rock aquifer, Raymond, California

    Cohen, Andrew J.B. [Univ. of California, Berkeley, CA (United States)

    1993-10-01

    The hydrogeologic properties of a shallow, fractured granitic rock aquifer in the foothills of the Sierra Nevada, California were investigated via the analysis of borehole geophysical logs and pumping tests. The drawdowns produced during these tests are not indicative of any simple conceptual aquifer model, and borehole logs show that the granite is intensely fractured. These observations are suggestive of a complex fracture-flow geometry which is extremely difficult to decipher. However, through the measurement of orientations of individual subsurface fractures from acoustic televiewer logs, and correlation between particular fractures and electrical resistivity and thermal-pulse flowmeter logs, it was found that the aquifer is, in general, comprised of two subhorizontal and nearly parallel zones of unloading fractures. Downhole flowmeter measurements taken in several wells provide further evidence for the inferred dual-layer structure of the aquifer, as well as yield quantitative measures of the contribution of flow from each zone. Analysis of drawdowns in pumped wells reveals that there are zones of relatively high transmissivity immediately around them. It was found that these properties, as well as a nearby zone of lower transmissivity, can account for their observed drawdowns. A numerical model was constructed to test whether these major heterogeneities could also account for the drawdowns in observation wells. This stepwise analysis of both the geophysical and hydrological data resulted in the formulation of a conceptual model of the aquifer which is consistent with observations, and which can account for its behavior when subjected to pumping.

  3. Rock mass characterization for storage of nuclear waste in granite

    Witherspoon, P.A.; Nelson, P.; Doe, T.; Thorpe, R.; Paulsson, B.; Gale, J.; Forster, C.

    1979-02-01

    The rock mass characterization in granite adjacent to an iron mine at Stripa, Sweden is being carried out by four different methods. The mechanical characterization includes monitoring the responses to thermal loading of jointed rock in situ, and mechanical tests on cores from 25 mm to 1 m in diameter. Geological characterization includes detailed surface mapping, subsurface mapping, and core mapping. Geophysical characterization uses a variety of borehole techniques, with emphasis on sonic methods. The hydrologic characterization is done through injection tests, pump tests, water pressure measurements, and controlled inflow tests to tunnels. Since the data are not yet complete, only tentative conclusions can be drawn regarding the best combinations of techniques for rock-mass characterization. Mapping studies are useful in defining continuity and fracture-system geometry. They do not give aperture, a factor significant in terms of both water flow and the displacements due to heating. Of the geophysical techniques, sonic methods appear most effective in fracture definition; other methods, gamma and neutron particularly, give data on radionuclide and water content and need further analysis with geologic and hydrologic data to determine their significance. Hydrologic work yields primarily aperture data, which with fracture geometry can be used to calculate directional permeabilities. Pressure measurements may provide one means of assessing fracture continuity. Finally, laboratory tests on large cores suggest considerable refinement in testing techniques may be needed before stress-aperture data can be extrapolated from laboratory to field

  4. Oxygen isotope studies of early Precambrian granitic rocks from the Giants Range batholith, northeastern Minnesota, U.S.A.

    Viswanathan, S.

    1974-01-01

    Oxygen isotope studies of granitic rocks from the 2.7 b.y.-old composite Giants Range batholith show that: (1) ??(O18)quartz values of 9 to 10 permil characterize relatively uncontaminated Lower Precambrian, magmatic granodiorites and granites; (2) granitic rocks thought to have formed by static granitization have ??(O18)quartz values that are 1 to 2 permil higher than magmatic granitic rocks; (3) satellite leucogranite bodies have values nearly identical to those of the main intrusive phases even where they transect O18-rich metasedimentary wall rocks; (4) oxygen isotopic interaction between the granitic melts and their O18-rich wall rocks was minimal; and (5) O18/O18 ratios of quartz grains in a metasomatic granite are largely inherited from the precursor rock, but during the progression - sedimentary parent ??? partially granitized parent ??? metasomatic granite ??? there is gradual decrease in ??(O18)quartz by 1 to 2 permil. ?? 1974.

  5. Rare metal granites and related rocks of the Ukrainian shield

    Esipchuk, K.Ye.

    1993-12-01

    Full Text Available Two rare metal leucocratic granites, Perga and Kamennaya complexes, can be distinquished on the Ukrainian shield. The Perga complex consists of medium- and coarse grained, mainly porphyric, biotite, riebeckite and aegirine granites, granite porphyries, microclinites and albitites with rare metal mineralization (genthelvite, phenacite, tantalite, cassiterite and wolframite etc.. Granites from several stocks (up to 30 km2 in the northwestern part of the shield, situated along the fracture zone, restricted the large Korosten pluton of rapakivi granites to the northwest. The age of these granites (Pb-Pb and U-Pb methods on zircon and monazite practically coincide with the age of rapakivi granites being 1750 Ma. Within the Korosten complex of rapakivi granites we consider that zinnwaldite granites, which are characterized by fluorite and topazine mineralization, represent the final phase of pluton. These granites differ from the Perga ones by their low content of rare metals. The Kamennaya Mogila complex lies in the southeastern part of the Ukrainian shield. It consists of biotite and muscovite-biotite, medium- and coarse-grained (also porphyric, and occasionally greisining granites with rare metal mineralization (cassiterite, columbite, molybdenite, wolframite and beryl. Granites form several stocks (5-30 km2 situated 10-30 km to the west-northwest of the South-Kalchik gabbro-syenite-granite pluton. Granitoids in both of these complexes have similar isotopic ages (1800 Ma. Leucocratic subalkaline granites (the Novoyanisol type are known within the pluton itself, occupying an intermediate position between the above mentioned in terms of mineral and geochemical composition. The gabbro-syenite-granite formation of the Nearazov region has a substantial similarity to the anorthosite-rapakivi-granite formation. In this respect the relation of each of them to rare metal granites is rather remarkable. This relation is, most probably, not only spatial, but

  6. Magmatic and Crustal Differentiation History of Granitic Rocks from Hf-O Isotopes in Zircon

    Kemp, , A. I. S.; Hawkesworth, , C. J.; Foster, , G. L.; Paterson, , B. A.; Woodhead, , J. D.; Hergt, , J. M.; Gray, , C. M.; Whitehouse, M. J.

    2007-02-01

    Granitic plutonism is the principal agent of crustal differentiation, but linking granite emplacement to crust formation requires knowledge of the magmatic evolution, which is notoriously difficult to reconstruct from bulk rock compositions. We unlocked the plutonic archive through hafnium (Hf) and oxygen (O) isotope analysis of zoned zircon crystals from the classic hornblende-bearing (I-type) granites of eastern Australia. This granite type forms by the reworking of sedimentary materials by mantle-like magmas instead of by remelting ancient metamorphosed igneous rocks as widely believed. I-type magmatism thus drives the coupled growth and differentiation of continental crust.

  7. Ground Water movement in crystalline rock aquifers

    Serejo, A.N.C.; Freire, C.; Siqueira, H.B. de; Frischkorn, H.; Torquato, J.R.F.; Santiago, M.M.F.; Barbosa, P.C.

    1984-01-01

    Ground water movement studies were performed in crystalline rock aquifers from the upper Acarau River hydrographic basin, state of Ceara, Brazil. The studies included carbon-14, 18 O/ 16 O and tritium measurements as well as chemical analysis. A total of 35 wells were surveyed during drought seasons. Carbon-14 values displayed little variation which implied that the water use was adequate despite of the slower recharge conditions. Fairly constant isotopic 18 O/ 16 O ratio values in the wells and their similarity with rainwater values indicated that the recharge is done exclusively by pluvial waters. A decreasing tendency within the tritium concentration values were interpreted as a periodic rainwater renewal for these aquifers. The chemical analysis demonstrated that there is in fact no correlation between salinity and the time the water remains in the aquifer itself. (D.J.M.) [pt

  8. The transition from granite to banded aplite-pegmatite sheet complexes: An example from Megiliggar Rocks, Tregonning topaz granite, Cornwall

    Breiter, K.; Ďurišová, J.; Hrstka, T.; Korbelová, Z.; Vašinová Galiová, M.; Müller, A.; Simons, B.; Shail, R. K.; Williamson, B. J.; Davies, J. A.

    2018-03-01

    The genetic relationship between a granite pluton and adjacent complex of rare-metal pegmatite-aplite-banded sheets (Megiliggar Sheet Complex - MSC) has been studied at the border of the Tregonning topaz granite at Megiliggar Rocks, Cornwall, SW England. Similarities in whole-rock chemical and mineralogical compositions, together with a gradual change in textures away from the granite margin, provide strong evidence for a genetic link between the Tregonning Granite and MSC. The sheets are likely to represent apophyses of residual melt which escaped from the largely crystallized roof of the granite pluton. The escaping melt was peraluminous, had a composition near the F, B, Li slightly enriched granite minimum, and, in comparison with other Cornish granites, was enriched in F, Li, Rb, Cs, Sn, W, Nb, Ta, and U, and depleted in Fe, Mg, Ca, Sr, Th, Zr, and REE. With increasing distance from the Tregonning Granite, the silicate melt crystallized as homogeneous leucogranite sheets and banded complex sheets (i.e. combinations of bands with granitic, aplitic and pegmatitic textures), then layered aplite-pegmatites; this sequence becoming progressively more depleted in the fluxing and volatile elements F, Li, Rb, and Cs, but showing no change in Zr/Hf ratios. The fixed Zr/Hf ratio is interpreted as indicating a direct genetic link (parental melt) between all rock types, however the melt progressively lost fluxing and volatile elements with distance from the granite pluton, probably due to wall-rock reaction or fluid exsolution and migration via fractures. Differentiation of the primary melt into Na-Li-F-rich and separate K-B-rich domains was the dominant chemical process responsible for the textural and mineral diversity of the MSC. On a large (cliff-section) scale, the proximal Na-Li-F-rich leucogranite passes through complex sheets into K-B-rich aplite-pegmatites, whilst at a smaller (<1 m) scale, the K-B-rich bands are interspersed (largely overlain) by Na

  9. Terrestrial gamma ray dose rates on Ryoke granitic rocks in Ikoma Mountains

    Ikeda, Tadashi; Ueshima, Masaaki; Shibayama, Motohiko; Hiraoka, Yoshitsugu; Muslim, Dicky

    2012-01-01

    We measured the γ dose rate of 16 rock bodies in the field, which belonged to Ryoke granitic rocks distributed over Ikoma Mountains. The measurement points were 190 spots, and the mean dose rate was 82.0 ± 21.0 nGy/h. Results of analysis were summarized as follows. (1) The distribution of the dose rate in the Fukihata quartz diorite showed that the rocks crystallization differentiation had progressed from the south to the north. (2) The dose rate of granite tended to arise with the increase of SiO 2 quantity, but in the Iwahashiyama granite, the Takayasuyama granite, the Omichi granite and the Katakami granite, it was revealed that the dose rate was low in spite of high SiO 2 quantity. (3) It became clear that the dose rate of Ryoke granitic rocks from the first stage to the fourth stage was high to be considered as a new rock body. (4) Because the relationship between the dose rate of rocks and the main chemical elements did not show a common characteristic, it may be that those rocks were formed from different Magma. (author)

  10. The transition from granite to banded aplite-pegmatite sheet complexes: An example from Megiliggar Rocks, Tregonning topaz granite, Cornwall

    Breiter, Karel; Ďurišová, Jana; Hrstka, Tomáš; Korbelová, Zuzana; Vašinová Galiová, M.; Müller, A.; Simons, B.; Shail, R. K.; Williamson, B. J.; Davies, J. A.

    302/303, March 2018 (2018), s. 370-388 ISSN 0024-4937 R&D Projects: GA ČR GA14-13600S Institutional support: RVO:67985831 Keywords : granite * aplite * pegmatite * magmatic layering * Megiliggar Rocks * Cornwall Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 3.677, year: 2016

  11. Chemical analysis of minerals in granitic rocks by electron probe micro analyser

    Hiraoka, Yoshihiro

    1994-01-01

    The chemical compositions of minerals in a few granitic rocks were determined by electron probe micro analyser (EPMA). The accurate analytical data for standard feldspar groups were obtained by correcting the low analytical values of sodium and potassium that were arised from the damage in EPMA analysis. Using this method, feldspar groups and biotites in three granitic rocks gathered from Hiei, Hira and Kurama areas respectively, were analyzed. As the results, the local characteristics were observed in the kinds of feldspar groups and the chemical compositions of biotites that were contained in granitic rocks. (author)

  12. Used Fuel Disposition in Crystalline Rocks: FY16 Progress Report

    Wang, Y. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hadgu, Teklu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kalinina, Elena Arkadievna [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jerden, James L. [Argonne National Lab. (ANL), Argonne, IL (United States); Copple, Jacqueline M. [Argonne National Lab. (ANL), Argonne, IL (United States); Cruse, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Ebert, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Buck, E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Eittman, R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tinnacher, R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tournassat, Christophe [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Davis, J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Viswanathan, H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Joseph, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-09-21

    The objective of the Crystalline Disposal R&D Work Package is to advance our understanding of long-term disposal of used fuel in crystalline rocks and to develop necessary experimental and computational capabilities to evaluate various disposal concepts in such media. FY16 continued to be a successful year in both experimental and modeling arenas in evaluation of used fuel disposal in crystalline rocks. The work covers a wide range of research topics identified in the R&D plan.

  13. Fractures inside crystalline rocks. Effects of deformations on fluid circulations

    Gentier, S.

    2005-01-01

    The modeling of fluid flows inside granite massifs is an important task for the evaluation of the feasibility of radioactive waste storage inside such formations. This document makes a synthesis of the works carried out since about 15 years, in particular by the French bureau of geological and mining research (BRGM), about the hydro-mechanical behaviour of a fracture and about the hydrodynamical characterization of fracture networks inside crystalline rocks: 1 - introduction; 2 - hydro-mechanical behaviour under normal stress: experimental results (hydro-mechanical behaviour, flow regimes, mechanical behaviour, test protocol, complementary tests, influence of samples size), geometrical interpretation of experimental results (relation with walls geometry, relation with voids geometry, relation with contacts geometry), hydro-mechanical modeling (hydraulic modeling, mechanical modeling); 3 - from the hydro-mechanical behaviour under normal stress to the coupling with heat transfers and chemistry: experiment for the study of the chemo-thermo-hydro-mechanical coupling (experimental results, relation with walls morphology), thermo-hydro-mechanical experiments, thermo-hydro-chemical experiments with fractures, conclusions; 4 - hydro-mechanical behaviour during shear: experimental results, geometrical interpretation (relation with the geometry of damaged zones, relation with voids geometry, relation with walls geometry), hydro-mechanical modeling (mechanical modeling, hydro-mechanical modeling of the behaviour during shear). (J.S.)

  14. Isotopic geochronology of granitic rocks from the Central Iberian Zone: comparison of methodologies

    Antunes, I. M. H. R.; Neiva, A. M. R.; Silva, M. M. V. G.

    2010-07-01

    Five granitic rocks, concentrically disposed from core to rim, were distinguished in the Castelo Branco pluton. U-Pb-Th electron microprobe monazite ages from granitic rocks are similar and ranging between 297-303 Ma. The granitic rocks from Castelo Branco pluton are 310 {+-} 1 Ma old, obtained by U-Pb (ID-TIMS) in separated zircon and monazite crystals, indicating a similar emplacement age for all granitic rocks of the pluton. Initial {sup 8}7Sr/{sup 8}6Sr isotopic ratios and {epsilon}Nd{sub 3}10 and {delta}{sup 1}8O values suggest three distinct pulses of granitic magma and that they are derived from partial melting of heterogeneous metasedimentary materials. The other granitic rocks are related by magmatic differentiation and show small variations in ({sup 8}7Sr/{sup 8}6Sr)310, {epsilon}Nd{sub 3}10 and {delta}{sup 1}8O. The granitic pluton of Castelo Branco shows a rare reverse zoning. (Author) 12 refs.

  15. The bowing potential of granitic rocks: rock fabrics, thermal properties and residual strain

    Siegesmund, S.; Mosch, S.; Scheffzük, Ch.; Nikolayev, D. I.

    2008-10-01

    The bowing of natural stone panels is especially known for marble slabs. The bowing of granite is mainly known from tombstones in subtropical humid climate. Field inspections in combination with laboratory investigations with respect to the thermal expansion and the bowing potential was performed on two different granitoids (Cezlak granodiorite and Flossenbürg granite) which differ in the composition and rock fabrics. In addition, to describe and explain the effect of bowing of granitoid facade panels, neutron time-of-flight diffraction was applied to determine residual macro- and microstrain. The measurements were combined with investigations of the crystallographic preferred orientation of quartz and biotite. Both samples show a significant bowing as a function of panel thickness and destination temperature. In comparison to marbles the effect of bowing is more pronounced in granitoids at temperatures of 120°C. The bowing as well as the thermal expansion of the Cezlak sample is also anisotropic with respect to the rock fabrics. A quantitative estimate was performed based on the observed textures. The effect of the locked-in stresses may also have a control on the bowing together with the thermal stresses related to the different volume expansion of the rock-forming minerals.

  16. The water retention of a granite rock fragments in High Tatras stony soils

    Novák, Viliam; Šurda, Peter

    2010-01-01

    The water retention capacity of coarse rock fragments is usually considered negligible. But the presence of rock fragments in a soil can play an important role in both water holding capacity and in hydraulic conductivity as well. This paper presents results of maximum water holding capacity measured in coarse rock fragments in the soil classified as cobbly sandy loam sampled at High Tatra mountains. It is shown, that those coarse rock (granite) fragments have the maximum retention capacity up...

  17. Host rock characteristics of uranium deposits of cataclastic-altered granite type

    Feng Mingyue

    1997-01-01

    The author expounds the host rock characteristics of uranium deposits of cataclastic-altered granite type, i.e., the high initial content of uranium, the high cataclasis of host rocks, the strong alteration of host rocks, the simple composition of host rocks favourable for the leaching of uranium, as well as the low content of harmful associated elements. These characteristics may be regarded as petrological criteria for recognition and prospecting for such type of uranium deposits

  18. Host rock characteristics of uranium deposits of cataclastic-altered granite type

    Mingyue, Feng [Beijing Research Inst. of Uranium Geology (China)

    1997-03-01

    The author expounds the host rock characteristics of uranium deposits of cataclastic-altered granite type, i.e., the high initial content of uranium, the high cataclasis of host rocks, the strong alteration of host rocks, the simple composition of host rocks favourable for the leaching of uranium, as well as the low content of harmful associated elements. These characteristics may be regarded as petrological criteria for recognition and prospecting for such type of uranium deposits.

  19. Uranium distribution and fixation in main types of climatic and stational pedogenesis on crystalline rocks

    Gueniot, B.

    1983-11-01

    An experimental and analytical study of uranium behavior in soils and of its distribution was carried out for bioclimatic pedogenesis on crystalline rocks, generally granites. Uranium distribution, and sometimes thorium) is compared to the distribution of tracers of pedogenesis (C, Fe, Al, Si, alkalis, clays). Uranium and thorium behavior is dependent of pedogenesis and can be leached or concentrated. Various fractions of soil alteration complexes and associated uranium can be isolated by chemical and physical fractionation and fixation sites for U are evidenced, efficiency is tested in situ. Adsorption is low onclays, fixation is frequent on oxyhydroxides, organic compounds are active for uranium complexation [fr

  20. Microstructural variation of vitrified floor tile incorporated with granitic rock waste

    Souza, A.J.; Holanda, J.N.F.

    2009-01-01

    The ornamental rock industry from Northwest Fluminense generates huge amounts of wastes in the form of a fine powder. These wastes are deposited in nature without any care about environmental degradation, which can cause damage to public health, pollution of the natural water sources, and silted banks of rivers. In addition, they also can to affect the landscape aesthetically. In this work was used a granitic rock waste from Santo Antonio de Padua-RJ. This waste is rich in alkaline oxides, which promote the formation of liquid phase and assist the densification of traditional ceramics. The ceramic bodies with up to 47.5% granitic rock waste were pressed at 50 MPa. The ceramic pieces were fired at 1250 deg C. The evolution of sintered microstructure was evaluated by scanning electron microscopy and X-ray diffraction. The results showed that the granitic rock waste influences significantly the microstructure of the sintered ceramic bodies. (author)

  1. Uranium distribution in Brazilian granitic rocks. Identification of uranium provinces

    Tassinari, C.G.G.

    1993-01-01

    The research characterized and described uranium enriched granitoids in Brazil. They occur in a variety of tectonic environments and are represented by a variety granite types of distinct ages. It may be deduced that in general they have been generated by partial melting process of continental crust. However, some of them, those with tonality composition, indicate a contribution from mantle derived materials, thus suggesting primary uranium enrichment from the upper mantle. Through this study, the identification and characterization of uranium enriched granite or uranium provinces in Brazil can be made. This may also help identify areas with potential for uranium mineralization although it has been note that uranium mineralization in Brazil are not related to the uranium enrichment process. In general the U-anomalous granitoids are composed of granites with alkaline composition and granite ''sensu strictu'' which comprise mainly of syenites, quartz-syenites and biotite-hornblende granites, with ages between 1,800 - 1,300 M.a. The U-anomalous belongings to this period present high Sr initial ratios values, above 0.706, and high Rb contents. Most of the U-enriched granitoids occur within ancient cratonic areas, or within Early to Mid-Proterozoic mobile belts, but after their cratonization. Generally, these granitoids are related to the border zones of the mobile belts or deep crustal discontinuity. Refs, 12 figs, 3 tabs

  2. Uranium migration and retention during weathering of a granitic waste rock pile

    Boekhout, F.; Gérard, M.; Kanzari, A.; Michel, A.; Déjeant, A.; Galoisy, L.; Calas, G.; Descostes, M.

    2015-01-01

    Highlights: • We investigate the environmental impact of the granitic waste rock piles. • The majority of the waste rocks in the pile is barren- or overburden rock. • The main neo-formed U-bearing phases are (Ca) and (Cu) uranyl phosphates. • Under circum-neutral pH conditions they do not pose an environment threat. - Abstract: This study investigates the post-mining evolution of S-type granitic waste rocks around a former uranium mine, Vieilles Sagnes (Haute Vienne, NW Massif Central, France). This mine was operated between 1957 and 1965 in the La Crouzille former world-class uranium mining district and is representative of intra-granitic vein-type deposits. 50 years after mine closure and the construction and subsequent re-vegetation of the granitic waste rock pile, we evaluate the environmental evolution of the rock pile, including rock alteration, neo-formation of U-bearing phases during weathering, and U migration. Vertical trenches have been excavated through the rock pile down to an underlying paleo-soil, allowing the investigation of the vertical differentiation of the rock pile and its influence on water pathways, weathering processes and U migration and retention. Arenization dominantly drives liberation of U, by dissolution of uraninite inclusions in the most alterable granitic minerals (i.e. K-feldspar and biotite). Retention of U in the matrix at the base of the waste rock pile, and in the underlying paleo-soil most likely occurs by precipitation of (nano-) uranyl phosphates or a combination of co-precipitation and adsorption reactions of U onto Fe (oxy)hydroxides and/or clay minerals. Even though U-migration was observed, U is retained in stable secondary mineral phases, provided the current conditions will not be modified

  3. Theoretical and laboratory investigations of flow through fractures in crystalline rock

    Witherspoon, P.A.; Watkins, D.J.; Tsang, Y.W.

    1981-01-01

    A theoretical model developed for flow through a deformable fracture subject to stresses was successfully tested against laboratory experiments. The model contains no arbitrary parameters and can be used to predict flow rates through a single fracture if the fractional fracture contact area can be estimated and if stress-deformation data are available. These data can be obtained from laboratory or in situ tests. The model has considerable potential for practical application. The permeability of ultralarge samples of fractured crystalline rock as a function of stresses was measured. Results from tests on a pervasively fractured 1-m-diameter specimen of granitic rock showed that drastically simplifying assumptions must be used to apply theoretical models to this type of rock mass. Simple models successfully reproduce the trend of reduced permeability as stress is applied in a direction normal to the fracture plane. The tests also demonstrated how fracture conductivity increases as a result of dilatancy associated with shear displacements. The effect of specimen size on the hydraulic properties of fractured rock was also investigated. Permeability tests were performed on specimens of charcoal black granite containing a single fracture subjected to normal stress. Results are presented for tests performed on a 0.914-m-diameter specimen and on the same specimen after it had been reduced to 0.764 m in diameter. The data show that fracture conductivity is sensitive to stress history and sample disturbance

  4. Diffusion in crystalline rocks of some sorbing and nonsorbing species

    Skagius, K.; Neretnieks, I.

    1983-01-01

    Laboratory experiments to determine the sorption and the rate of diffusion of cesium and strontium in pieces of granite have been performed. The effective diffusivity, D sub (p) x E sub (p) was found to be 1 - 2 x 10 - 12 m 2 /s for both cesium and strontium. The diffusion of non-sorbing species in granites and other rock materials have been studied in laboratory scale. The non-sorbing species were iodide, tritiated water, Cr-EDTA and Uranine. In granites the effective diffusivities were determined to be 0.7-1.3 x 10 - 13 m 2 /s for iodide and 1.3 - 1.8 x 10 - 13 m 2 /s for tritiated water. Electrical resistivity measurements in salt water saturated rock cores have been performed. The resistivity is measured in the saturated core and in the salt solution with which the core has been saturated. The ratio between these two resistivities has a direct relation to the ratio of the effective diffusivity for a component in the rock material and the diffusivity in free water for the same component. The results from the electrical resistivity measurements and the experiments with diffusion of non-sorbing species are in fair agreement. The effective diffusivity for cesium and strontium (sorbing species) are, however, more than ten times higher than expected from the results of diffusion of non-sorbing species and the electrical resistivity measurements. This is interpreted as an effect of surface diffusion. (Authors)

  5. Proceedings of the scientific visit on crystalline rock repository development.

    Mariner, Paul E.; Hardin, Ernest L.; Miksova, Jitka [RAWRA, Czech Republic

    2013-02-01

    A scientific visit on Crystalline Rock Repository Development was held in the Czech Republic on September 24-27, 2012. The visit was hosted by the Czech Radioactive Waste Repository Authority (RAWRA), co-hosted by Sandia National Laboratories (SNL), and supported by the International Atomic Energy Agency (IAEA). The purpose of the visit was to promote technical information exchange between participants from countries engaged in the investigation and exploration of crystalline rock for the eventual construction of nuclear waste repositories. The visit was designed especially for participants of countries that have recently commenced (or recommenced) national repository programmes in crystalline host rock formations. Discussion topics included repository programme development, site screening and selection, site characterization, disposal concepts in crystalline host rock, regulatory frameworks, and safety assessment methodology. Interest was surveyed in establishing a %E2%80%9Cclub,%E2%80%9D the mission of which would be to identify and address the various technical challenges that confront the disposal of radioactive waste in crystalline rock environments. The idea of a second scientific visit to be held one year later in another host country received popular support. The visit concluded with a trip to the countryside south of Prague where participants were treated to a tour of the laboratory and underground facilities of the Josef Regional Underground Research Centre.

  6. Susceptibility of Granite Rock to scCO2/Water at 200 degrees C and 250 degrees C

    Sugama, T.; Gill, S., Ecker, L., Butcher, T., Warren, J.

    2011-01-01

    Granite rock comprising anorthoclase-type albite and quartz as its major phases and biotite mica as the minor one was exposed to supercritical carbon dioxide (scCO{sub 2})/water at 250 C and 13.78 MPa pressure for 104 hours. For comparison purpose, four other rocks, albite, hornblende, diorite, and quartz, also were exposed. During the exposure of granite, ionic carbonic acid, known as the wet carbonation reactant, preferentially reacted with anorthoclase-type albite and biotite, rather than with quartz. The susceptibility of biotite to wet carbonation was higher than that of anorthoclase-type albite. All the carbonation by-products of anorthoclase-type albite were amorphous phases including Na- and K-carbonates, a kaolinite clay-like compound, and silicon dioxide, while wet carbonation converted biotite into potassium aluminum silicate, siderite, and magnesite in crystalline phases and hydrogen fluoride (HF). Three of these reaction by-products, Na- and K-carbonates and HF, were highly soluble in water. Correspondingly, the carbonated top surface layer, about 1.27 mm thick as carbonation depth, developed porous microstructure with numerous large voids, some of which have a size of {>=} 10 {mu}m, reflecting the erosion of granite by the leaching of these water-soluble reaction by-products. Comparing with this carbonation depth, its depth of other minerals was considerable lower, particularly, for hornblende and diorite with 0.07 and 0.02 mm, while no carbonate compound was detected in quartz. The major factor governing these low carbonation depths in these rocks was the formation of water-insensitive scale-like carbonate by-products such as calcite (CaCO{sub 3}), siderite (FeCO{sub 3}), and magnesite (MgCO{sub 3}). Their formation within the superficial layer of these minerals served as protective barrier layer that inhibits and retards further carbonation of fresh underlying minerals, even if the exposure time was extended. Thus, the coverage by this barrier layer

  7. Retardation of radionuclide transport by fracture flow in granite and argillaceous rocks

    Bradbury, M.H.; Green, A.

    1985-11-01

    Laboratory techniques have been developed for the measurement of diffusion rates and permeabilities through highly consolidated rock samples. The work has predominantly concentrated on the generation of diffusion data for slates and granites in particular. Rock properties fundamental to mass transfer processes have been obtained. Diffusion rates have been measured through weathered granite fissure surfaces and as a function of distance from such surfaces on core samples obtained from Troon, Cornwall. Pore connectivity over metre distances in granite cores has been shown to exist and diffusion coefficients were measured as a function of confining pressure in a specially designed rig. The Dsub(i) (intrinsic diffusion coefficient) values determined at ambient pressure were approximately a factor of 2 greater than those measured at pressures equivalent to 500 m of rock overburden. Some initial experiments on the accessibility of the pore space in granites to colloids based on a permeability technique indicated that such particles neither blocked pores nor penetrated through 15 mm thick samples over times of the order 2 to 3 thousand hours. Diffusion rates through samples of Canadian granites, some of which contained weathered fissure surfaces, were measured. (author)

  8. Natural analogue and microstructural studies in relation to radionuclide retardation by rock matrix diffusion in granite

    Montoto, M.; Rodriguez Rey, A.; Ruiz de Argandona, V.G.; Calleja, L.; Menendez, B.

    1992-01-01

    The possibility that radionuclide retardation by rock matrix diffusion will be limited in granitic rocks by geological factors is studied, as well as the possibility that diffusion will be confined to a narrow zone from water-conducting fractures. Petrophysical measurements, uranium series and geochemical analyses in the rock adjacent to fractures, have been performed to establish the extent of fracture-related microstructural changes that might influence the potential for diffusion and whether or not there is any record of diffusion of uranium, its daughters, or other elements. The results obtained from El Berrocal (Spain), Stripa (Sweden) and White-shell (Canada) granites, suggest that: (a) there is a zone adjacent to the fractures (generally less than 100 mm) where microstructural changes and enhanced uranium mobility exist; (b) the evidence for diffusion having taken place in the rock is confined largely to this zone. So, it appears that diffusivity determinations on rock collected away from the influence of fractures will not give representative data for diffusion modelling, in addition to the effect of distressing after removing rocks from depth. It is suggested that diffusion will be of limited effectiveness as a retardation mechanism in many granitic rocks, particularly in water movement confined to narrow channels where access by nuclides to the fracture walls is restricted. 51 refs., 56 figs., 9 tabs., 9 appendices

  9. A compilation of radioelement concentrations in granitic rocks of the contiguous United States

    Stuckless, J.S.; VanTrump, G. Jr.

    1982-01-01

    Concentration data for uranium, thorium, and potassium have been compiled for approximately 2,500 granitic samples from the contiguous United States. Uranium and thorium concentrations and ratios involving these elements exhibit a log-normal distribution with statistical parameters. In order to check for a bias in the results due to high concentrations of data in anomalous or heavily sampled areas, the data were reevaluated by averaging all analyses within a 0.5 0 latitude by 0.5 0 longitude grid. The resulting data set contains 330 entries for which radioelements are log-normally distributed. Mean values are not significantly different from those of the ungridded data, but standard deviations are lower by as much as nearly 50 percent. The areal distribution of anomalously high values (more than one standard deviation greater than the geometric mean) does not delineate large uranium districts by either treatment of the data. There is sufficient information for approximately 1,500 samples to permit subdivision of the granites by degree of alumina saturation. Relative to the six variables listed above, peraluminous samples have slightly lower mean values, but the differences are not statistically significant. Standard deviations are also largest for the peraluminous granites with α for Th/U nearly 3 times larger for peraluminous granite than for metaluminous granite. Examination of the variations in Th/U ratios for a few specific granites for which isotopic data are available suggests that variability is caused by late-stage magmatic or secondary processes that may be associated with ore-forming processes. Therefore, although anomalous radioelement concentrations in granitic rocks do not seem to be useful in delineating large uranium provinces with sediment-hosted deposits, highly variable uranium concentrations or Th/U ratios in granitic rocks may be helpful in the search for uranium deposits

  10. Depth optimization for the Korean HLW repository System within a discontinuous and saturated granitic rock mass

    Kim, Jhin Wung; Bae, Dae Seok; Choi, Jong Won

    2005-12-01

    The present study is to evaluate the material properties of the compacted bentonite, backfill material, canister cast iron insert, and the rock mass for the Korean HLW repository system. These material properties are either measured, or taken from other countries, through the evaluation of the thermal, hydraulic, and mechanical interaction behavior of a repository. After the evaluation of the material properties, the most appropriate and economical depth as well as the layout of a single layer repository is to be recommended. Material properties used for the granitic rock mass, rock joints, PWR spent fuel, disposal canister, compacted bentonite, backfill material, and ground water are the data collected domestically, and foreign data are used for some of the data not available domestically. The repository model includes a saturated granitic rock mass with joints, PWR spent fuel in a disposal canister surrounded by compacted bentonite inside a deposition hole, and backfill material in the rest of the space within a repository cavern

  11. Stability of bentonite gels in crystalline rock

    Pusch, R.

    1983-02-01

    The present, extended study comprises a derivation of a simple rock model as a basis for calculation of the penetration rate of bentonite and of the groundwater flow rate, which is a determinant of the erodibility of the protruding clay film. This model, which is representative of a gross permeability of about 10 -8 - 10 -9 m/s, implies a spectrum of slot-shaped joints with apertures ranging between 0.1 and 0.5 mm. It is concluded that less than 2percent of the highly compacted bentonite will be lost into traversing joints in 10 6 years. A closer analysis, in which also Poiseuille retardation and short-term experiments were taken into account, even suggests that the penetration into the considered joints will be less than that. The penetration rate is expected to be 1 decimeter in a few hundred years. The risk of erosion by flowing groundwater was estimated by comparing clay particle bond strength, evaluated from viscometer tests, and theoretically derived drag forces, the conclusion being that the maximum expected water flow rate in the widest joints of the rock model (4 times 10 -4 m/s) is not sufficient to disrupt the gel front or the large individual clay flocs that may exist at this front. The experiments support the conclusion that erosion will not be a source of bentonite loss. A worst case scenario with a shear zone being developed across deposition holes is finally considered and in addition to this, the conditions in the fracture-rich tunnel floor at the upper end of the deposition holes are also analysed. This study shows that even if the rock is much more fractured than normal conditions would imply, the bentonite loss is expected to be very moderate and without substantial effect on the barrier functions of the remaining clay cores in the deposition holes. (author)

  12. Technical concept for rock mechanics tests, Climax Granite, NTS

    Hearst, J.R.

    1979-02-01

    If we are to believe our predictions of the thermomechanical behavior of the material surrounding a nuclear waste repository in granite, we must test the computational methods used in making the predictions. If thermal loadings appropriate to a real repository are used, thermally induced displacements and strains are quite small, and available geotechnical instrumentation is only marginally able to measure these effects to the accuracy desired to make thorough tests of the predictions. We outline a three-step program to address these issues. (1) Conduct experiments in which the thermal loading is large compared to that induced by a real repository. This will permit us to make accurate measurements with available instrumentation. (2) Simultaneously, develop improved instrumentation that will enable us to make accurate measurements of motions induced by thermal loadings appropriate to a real repository. (3) Finally, conduct a second set of experiments, with the improved instrumentation and thermal loading similar to that of a real repository in granite. If we can predict the effects of this thermal loading to a few percent over distances of tens of meters for time periods of a few years, and demonstrate that these predictions are correct, we can have reasonable confidence that, using the same methods, we can predict the behavior over thousands of meters for hundreds of years to an order of magnitude. That accuracy should be satisfactory for those distances and times

  13. Interim rock mass properties and conditions for analyses of a repository in crystalline rock

    Tammemagi, H.Y.; Chieslar, J.D.

    1985-03-01

    A summary of rock properties for generic crystalline rock is compiled from literature sources to provide the input data for analyses of a conceptual repository in crystalline rock. Frequency histograms, mean values and ranges of physical, mechanical, thermal, and thermomechanical properties, and the dependence of these properties on temperature are described. A description of the hydrogeologic properties of a crystalline rock mass and their dependence on depth is provided. In addition, the temperature gradients, mean annual surface temperature, and in situ stress conditions are summarized for the three regions of the United States currently under consideration to host a crystalline repository; i.e., the North Central, Northeastern, and Southeastern. Brief descriptions of the regional geology are also presented. Large-scale underground experiments in crystalline rock at Stripa, Sweden, and in Climax Stock in Nevada, are reviewed to assess whether the rock properties presented in this report are representative of in situ conditions. The suitability of each rock property and the sufficiency of its data base are described. 110 refs., 27 figs., 4 tabs

  14. Used Fuel Disposal in Crystalline Rocks. FY15 Progress Report

    Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-20

    The objective of the Crystalline Disposal R&D Work Package is to advance our understanding of long-term disposal of used fuel in crystalline rocks and to develop necessary experimental and computational capabilities to evaluate various disposal concepts in such media. Chapter headings are as follows: Fuel matrix degradation model and its integration with performance assessments, Investigation of thermal effects on the chemical behavior of clays, Investigation of uranium diffusion and retardation in bentonite, Long-term diffusion of U(VI) in bentonite: dependence on density, Sorption and desorption of plutonium by bentonite, Dissolution of plutonium intrinsic colloids in the presence of clay and as a function of temperature, Laboratory investigation of colloid-facilitated transport of cesium by bentonite colloids in a crystalline rock system, Development and demonstration of discrete fracture network model, Fracture continuum model and its comparison with discrete fracture network model.

  15. Mixing induced reactive transport in fractured crystalline rocks

    Martinez-Landa, Lurdes; Carrera, Jesus; Dentz, Marco; Fernàndez-Garcia, Daniel; Nardí, Albert; Saaltink, Maarten W.

    2012-01-01

    In this paper the solute retention properties of crystalline fractured rocks due to mixing-induced geochemical reactions are studied. While fractured media exhibit paths of fast flow and transport and thus short residence times for conservative solutes, at the same time they promote mixing and dilution due to strong heterogeneity, which leads to sharp concentration contrasts. Enhanced mixing and dilution have a double effect that favors crystalline fractured media as a possible host medium for nuclear waste disposal. Firstly, peak radionuclide concentrations are attenuated and, secondly, mixing-induced precipitation reactions are enhanced significantly, which leads to radionuclide immobilization. An integrated framework is presented for the effective modeling of these flow, transport and reaction phenomena, and the interaction between them. In a simple case study, the enhanced dilution and precipitation potential of fractured crystalline rocks are systematically studied and quantified and contrasted it to retention and attenuation in an equivalent homogeneous formation.

  16. Link between the granitic and volcanic rocks of the Bushveld Complex, South Africa

    Schweitzer, J. K.; Hatton, C. J.; De Waal, S. A.

    1997-02-01

    Until recently, it was proposed that the Bushveld Complex, consisting of the extrusive Rooiberg Group and the intrusive Rashoop Granophyre, Rustenburg Layered and Lebowa Granite Suites, evolved over a long period of time, possibly exceeding 100 Ma. Most workers therefore considered that the various intrusive and extrusive episodes were unrelated. Recent findings suggest that the intrusive, mafic Rustenburg Layered Suite, siliceous Rashoop Granophyre Suite and the volcanic Rooiberg Group were synchronous, implying that the Bushveld igneous event was short-lived. Accepting the short-lived nature of the complex, the hypothesis that the granites are genetically unrelated to the other events of the Bushveld Complex can be reconsidered. Re-examination of the potential Rooiberg Group/Lebowa Granite Suite relationship suggests that the granites form part of the Bushveld event. Rhyolite lava, granite and granophyre melts originated from a source similar in composition to upper crustal rocks. This source is interpreted to have been melted by a thermal input associated with a mantle plume. Granite intruded after extrusion of the last Rooiberg rhyolite, or possibly overlapped in time with the formation of the youngest volcanic flows.

  17. Underground Research Laboratories for Crystalline Rock and Sedimentary Rock in Japan

    Shigeta, N.; Takeda, S.; Matsui, H.; Yamasaki, S.

    2003-02-27

    The Japan Nuclear Cycle Development Institute (JNC) has started two off-site (generic) underground research laboratory (URL) projects, one for crystalline rock as a fractured media and the other for sedimentary rock as a porous media. This paper introduces an overview and current status of these projects.

  18. Determination of rare-earth elements content in granitic rocks by argon plasma emission spectrometry

    Merodio, J.C.; Martinez, J.M.

    1990-01-01

    A method has been developed that enables the rare-earth elements in granitic rocks to be measured sequentially, using an inductively coupled plasma (ICP) source spectrometer with medium spectral resolution (0,02nm). The rocks were dissolved in an open system with a mixture of nitric-hydrofluoric-perchloric acids. Any residues remaining at this stage were removed by filtration and digested using a mini-fusion method with lithium tetraborate. Prior to the excitation in the spectrometer the rare-earth group was separated from other constituents using cation-exchange chromatography. A detailed study of spectral interferences and the evaluation of the detection limits have been performed. Five geochemical reference sample (granitic rocks) were analyzed and the obtained results agree favourably with recommended values and with reported determinations, using high spectral resolution ICP spectrometry. (Author) [es

  19. Layout Optimization for the Repository within a discontinuous and saturated granitic rock mass

    Kim, Jhin Wung; Choi, Jong Won; Bae, Dae Seok

    2005-12-01

    The objective of the present study is a layout optimization of a single and double layer repositories within a repository site with special joint set arrangements. Single and double layer repository models, subjected to the variation of repository depth, cavern spacing, pitch, and layer spacing, are analyzed for the thermal, hydraulic, and mechanical interaction behavior during the period of 2000 years from waste emplacement. Material properties used for the granitic rock mass, rock joints, PWR spent fuel, disposal canister, compacted bentonite, backfill material, and groundwater are the data collected domestically, and foreign data are used for some of the data not available domestically. The repository model includes a saturated granitic rock mass with joints, PWR spent fuel in a disposal canister surrounded by compacted bentonite inside a deposition hole, and backfill material in the rest of the space within a repository cavern

  20. SITE-94. Estimated rates of redox-front migration in granitic rocks

    Arthur, R.C.

    1996-10-01

    Analytical models for the rate of migration of oxidizing groundwaters are derived based on the stationary-state approximation to coupled fluid flow and water-rock interaction, and are constrained by molar concentrations of ferrous silicate, oxide, and sulfide minerals in the granites and associated fractures comprising the host rock beneath Aespoe. Model results indicate that small amounts of ferrous minerals in Aespoe granites and fractures will retard the downward migration of oxidizing conditions that could be generated by infiltration of glacial meltwaters during periods of glacial maxima and retreat. Calculated front velocities are retarded relative to Darcy fluxes observed in conductive fracture zones at Aespoe (0.3 to 3 m/y) by factors ranging from 10 -3 to 10 -4 . Corresponding times for the front to migrate 500 m vary from 5,100 to 4,400,000 years. Retardation efficiency depends on mineralogy and decreases in the order: fractures > altered granites > unaltered granite. The most conductive structures in these rocks are therefore the most efficient in limiting the rate of front migration. Periods of recharge during glaciation are comparable to times required for an oxidizing front to migrate to repository levels. This suggests an oxidizing front could reach repository depths during a single glacial-interglacial event. The persistence of oxidizing conditions could be relatively short lived, however, because reversal of flow conditions driven by the advance and retreat of ice sheets could cause reducing conditions to be restored. 27 refs

  1. Temporal evolution of a granitic rock under thermal loads generated by fission products

    Ventura, M.A.; Ferreri, J.C.

    1985-01-01

    A parametric study of the thermal history of a granitic mass under thermal loads originating in terminal subproducts of the fuel cycle is performed. Variations of the conductivity and density of the rock and the unit cell dimensions are considered. In this way it was tried to delimit (for short time intervals of the order of 100 years) the influence of possible uncertainties in the rock's knowledge on the results of interest for the engineering design. In the reasonable situations considered, the maximum temperature in the rock did not rise over 80 deg C. (Author) [es

  2. Deep fracturation of granitic rock mass. Fracturation profonde des massifs rocheux granitiques

    Bles, J L; Blanchin, R; Bonijoly, D; Dutartre, P; Feybesse, J L; Gros, Y; Landry, J; Martin, P

    1986-01-01

    This documentary study realized with the financial support of the European Communities and the CEA aims at the utilization of available data for the understanding of the evolution of natural fractures in granitic rocks from the surface to deep underground, in various feasibility studies dealing with radioactive wastes disposal. The Mont Blanc road tunnel, the EDF Arc-Isere gallerie, the Auriat deep borehole and the Pyrenean rock mass of Bassies are studied. In this study are more particularly analyzed the relationship between small fractures and large faults, evolution with depth of fracture density and direction, consequences of rock decompression and relationship between fracturation and groundwater.

  3. Isotopic geochronology of granitic rocks from the Central Iberian Zone: comparison of methodologies

    Antunes, I. M.H.R.

    2010-06-01

    Full Text Available Five granitic rocks, concentrically disposed from core to rim, were distinguished in the Castelo Branco pluton. U-Pb-Th electron microprobe monazite ages from granitic rocks are similar and ranging between 297-303 Ma. The granitic rocks from Castelo Branco pluton are 310 ± 1 Ma old, obtained by U-Pb (ID-TIMS in separated zircon and monazite crystals, indicating a similar emplacement age for all granitic rocks of the pluton. Initial 87Sr/86Sr isotopic ratios and epsilon-Nd310 and delta-18O values suggest three distinct pulses of granitic magma and that they are derived from partial melting of heterogeneous metasedimentary materials. The other granitic rocks are related by magmatic differentiation and show small variations in (87Sr/86Sr310, epsilon-Nd310 and delta-18O. The granitic pluton of Castelo Branco shows a rare reverse zoning.

    En el plutón de Castelo Branco, se distinguen cinco granitoides, dispuestos concéntricamente de núcleo a borde del plutón. Las edades U-Pb-Th obtenidas en cristales de monacita por microsonda electrónica en estos granitoides son similares entre sí y varían entre 297 y 303 Ma. Los resultados de datación por U-Pb (ID-TIMS en cristales de circón y de monacita de los tres granitos seleccionados, indican una edad de implantación de 310 ± 1 Ma y que son rocas emplazadas simultáneamente. Las relaciones isotópicas iniciales de 87Sr/86Sr y los valores de epsilon-Nd310 y delta-18O de los tres pulsos magmáticos son característicos de granitos resultantes de anatexia cortical a partir de rocas metasedimentarias heterogéneas. En la secuencia de diferenciación magmática, las rocas graníticas presentan pequeñas variaciones en (87Sr/86Sr310, epsilon-Nd310 y delta-18O. El plutón de Castelo Branco presenta un

  4. Rationale for geological isolation of high-level radioactive waste, and assessment of the suitability of crystalline rocks

    Smedes, H.W.

    1980-01-01

    This report summarizes the disposal objective to be met and the requisite geotechnical criteria to meet that objective; evaluates our present ability to determine whether certain criteria can be met and to predict whether they will continue to be met; discusses the consequences of failure to meet certain criteria; assesses what is known about how crystalline rocks meet those criteria; lists important gaps in our knowledge that presently preclude final assessment of suitability; and suggests priority research to fill those gaps. The report presents an elaboration of the above-stated behavior and suitability of crystalline rocks, and a rationale of site-selection in support of the recommended prompt and intensive study of granite and other crystalline rocks as potentially highly suitable candidate media for radioactive waste disposal. An overview is presented on what the rocks are, where they are, and what the critical attributes are of various crystalline-rock terranes in the conterminous United States. This is intended to provide a basis to aid in selecting, first regions, and then sites within those regions, as candidate repository sites

  5. The role of the microfissuration of the rock matrix in the abrasion resistance of ornamental granitic rocks

    Rodríguez-Rey, Angel; Sanchez-Delgado, Nuria; Camino, Clara; Calleja, Lope; Ruiz de Argandoña, Vicente G.; Setien, Alexia

    2015-04-01

    The microcrack density and the abrasion resistance of five ornamental granites (Albero, Gris Alba, Mondariz, Rosa Porriño and Traspieles) from Galicia (NW Spain) have been quantified as part of a research aimed to interpret the cuttability of the rocks in relation to the petrophysical properties of the rock matrix. Large blocks from the quarries have been cut with an industrial saw and the microcrack density and the abrasion resistance have been measured in two surfaces: H, parallel to the cut surface; T, perpendicular both to the cut surface and the cutting direction. Both planes are perpendicular to the rift plane, as it is known in quarry works. The microcrack density has been quantified following an stereological procedure applied to polished sections imaged under scanning electron microscopy. The magnification of the images allowed the study of microcracks as narrow as 2 microns in aperture. The density has been quantified in terms of length of microcrack traces per surface unit so possible anisotropies of the microcrack network could be detected. The obtained values are in the typical range for this type of rocks although the Traspieles granite shows a higher value due to its weathering degree (H: 5.11, T: 5.37 mm/mm2). The values measured in the two surfaces (H and T) are quite similar in four of the rocks; only the Albero granite shows a marked anisotropy (H: 2.76 T: 3.53 mm/mm2). The abrasion resistance of the rocks has been measured following the european standard EN 14157:2004 using the capon method. The rocks can be classified in two groups according to their abrasion resistance. Rosa Porriño, Gris Alba and Mondariz granites are the more resistant to abrasion with values around 16-17 mm. Albero and Traspieles granites are less resistant with values higher than 19 mm. The results show a good correlation between the microcrack density and the abrasion resistance. As can be expected the rocks with high microcrack density show low abrasion resistance. The

  6. Geophysical characterization of an active hydrothermal shear zone in granitic rocks

    Zahner, Tobias; Baron, Ludovic; Holliger, Klaus; Egli, Daniel

    2016-04-01

    Hydrothermally active faults and shear zones in the crystalline massifs of the central Alps are currently of particular interest because of their potential similarities and analogies with planned deep petrothermal reservoirs in the Alpine foreland. In order to better understand such hydrothermal systems, a near-vertical, hydrothermally active shear zone embedded in low-permeability granitic rocks has been drilled. This borehole is located on the Grimsel Pass in the central Swiss Alps, has an inclination of 24 degrees with regard to the vertical, and crosses the targeted shear zone between about 82 and 86 meters depth. The borehole has been fully cored and a comprehensive suite of geophysical logging data has been acquired. The latter comprises multi-frequency sonic, ground-penetrating radar, resistivity, self-potential, gamma-gamma, neutron-neutron, optical televiewer, and caliper log data. In addition to this, we have also performed a surface-to-borehole vertical seismic profiling experiment. The televiewer data and the retrieved core samples show a marked increase of the fracture density in the target region, which also finds its expression in rather pronounced and distinct signatures in all other log data. Preliminary results point towards a close correspondence between the ground-penetrating radar and the neutron-neutron log data, which opens the perspective of constraining the effective fracture porosity at vastly differing scales. There is also remarkably good agreement between the sonic log and the vertical seismic profiling data, which may allow for assessing the permeability of the probed fracture network by interpreting these data in a poroelastic context.

  7. Studies of ionic diffusion in crystalline rock

    Ohlsson, Yvonne

    2001-01-01

    Matrix diffusion is of great importance in delaying radionuclides escaping from a deep geologic repository, on their way to the biosphere. There are, however, poorly understood mechanisms related to transport in pores with charged pore surfaces. Ions are affected by this charge and may be repelled or attracted by it. The rate of transport may be reduced, or even enhanced, as a result of this. Transport of ions is studied by traditional diffusion experiments, but mainly by a faster electrical conductivity method. With this method the pore connectivity, the formation factor variability and its relation to the porosity, as well as the surface conductivity are investigated. The method is compared. with traditional diffusion experiments, and an in-situ application is suggested and qualitatively tested. Furthermore, surface diffusion is studied by evaluating literature data and recently developed diffusion models. The pore connectivity reached to a depth of at least 15 cm in the rocks studied. The formation factor did not generally decrease with increasing sample length. It was also found that not only cations in the free pore water add to the electrical conductivity, but also at least part of those sorbed to the pore surfaces of the minerals. This surface conductivity influences the determination of the formation factor in low ionic strength pore waters, and was also found to be a function of the formation factor. It was furthermore dependent on the type of ion at the surface, giving for example a higher conductivity for Na + than for Cs + . It is not fully understood which part of the sorbed ions that are mobile. A simple model was developed assigning the mobile ions to the diffuse layer, and this model explained experimental data for diffusion of Cs + in clay well. This is contradicted by surface conductivity measurements that have shown that most mobile ions are found behind the Stern layer. The in-situ formation factor determination method seems promising. The most

  8. Radwaste storage in crystalline rocks: a natural analog

    Brookins, D.G.; Abashian, M.S.; Cohen, L.H.; Wollenberg, H.A.

    1982-01-01

    The Eldora-Bryan Stock (Colorado) intruded the 1.4-1.6 billion year old metamorphic rocks of the Idaho Springs Formation 55 million years ago. The stock may be considered a giant analog of a radwaste form without canister or engineered backfill barriers. The authors' lanthanide studies show the following: (1) The intrusive rocks remained as a closed system. (2) Lanthanide/chondrite versus ionic radius plots show only local redistribution in the immediate contact zone, and that rocks in this zone have not gained lanthanides from the magma. (3) No whole rock perturbations for the lanthanides are noted at distances greater than 3 m from the contact. Stable oxygen isotopic variations show a narrow 9.0 +- 0.3 per mille range for the intrusive rocks and whole rock values from 7.6 to 10.0 per mille for the intruded rocks. The authors conclude: (1) The Idaho Springs Formation was not penetrated by hydrothermal fluids from the Eldora-Bryan magma except possibly on a local scale within 3 m of the contact. (2) The light lanthanides may be locally redistributed in the immediate contact zone, but without additions from the magma. (3) The oxygen isotopic data imply lack of hydrothermal fluids from the magma penetrating the intruded rocks, even in the highest temperature contact zones. Whole rock data imply closed system conditions for Rb, Sr, Th, U, Pb even where mineral ages have been lowered. Data for Co, Cr, Sc, Fe, Cs also indicate retention in whole rock systems and no exchange with the magma. The combined chemical, isotopic, petrographic and theoretical data and calculations indicate suitability of rocks of the Idaho Springs Formation, and thus of many types of crystalline rocks as well, for possible use for the storage of radioactive waste

  9. Characterization of microbial communities in deep groundwater from granitic rock

    Jain, D.K.; Stroes-Gascoyne, S.; Providenti, M.; Tanner, C.; Cord, I.

    1997-01-01

    The microbial characteristics of deep granitic nutrient-poor groundwater from two boreholes at the Underground Research Laboratory of Atomic Energy of Canada Limited were studied. Scanning electron microscopy of the groundwater samples revealed significant numbers of bacteria of various sizes and shapes, including spherical, rod, and curved shaped. A few bacteria with appendages were also observed. Significant numbers of bacteria (∼l0 5 /mL) were enumerated using acridine orange (AO) staining. An active microbial population was detected with three direct methods and it ranged from 1 to 83% of the AO count, depending on the method used. Culturable aerobic and anaerobic (including facultative) heterotrophic bacteria ranged from 0.06 to 10.2% and 0.008 to 7.35%, respectively, of the AO count. Denitrifying. N 2 - fixing, sulphate-reducing, and iron-precipitating bacteria were present, but no iron-oxidizing bacteria or methanogens could be detected. Tentative identification of 160 isolates using the Biolog system showed a predominance of three Pseudomonas species, P. fluorescens, P. marginalis, and P. corrugata. Phospholipid fatty acid analysis showed that the bacteria in the groundwater samples faced starvation stress. However, laboratory studies showed that these bacteria can efficiently uptake and mineralize organic substrates when supplied. (author)

  10. Chemical and isotopic studies of granitic Archean rocks, Owl Creek Mountains, Wyoming: Geochronology of an Archean granite, Owl Creek Mountains, Wyoming

    Hedge, C.E.; Simmons, K.R.; Stuckless, J.S.

    1986-01-01

    Rubidium-strontium analyses of whole-rock samples of an Archean granite from the Owl Creek Mountains, Wyo., indicate an intrusive age of 2640 ± 125 Ma. Muscovite-bearing samples give results suggesting that these samples were altered about 2300 Ma. This event may have caused extensive strontium loss from the rocks as potassium feldspar was altered to muscovite. Alteration was highly localized in nature as evidence by unaffected rubidium-strontium mineral ages in the Owl Creek Mountains area. Furthermore, the event probably involved a small volume of fluid relative to the volume of rock because whole-rock δ 18 O values of altered rocks are not distinct from those of unaltered rocks. In contrast to the rubidium-strontium whole-rock system, zircons from the granite have been so severely affected by the alteration event, and possibly by a late-Precambrian uplift event, that the zircon system yields little usable age information. The average initial 87 Sr/ 86 Sr (0.7033 ± 0.0042) calculated from the isochron intercept varies significantly. Calculated initial 87 Sr/ 86 Sr ratios for nine apparently unaltered samples yield a range of 0.7025 to 0.7047. These calculated initial ratios correlate positively with whole-rock δ 18 O values; and, therefore, the granite was probably derived from an isotopically heterogeneous source. The highest initial 87 Sr/ 86 Sr ratio is lower than the lowest reported for the metamorphic rocks intruded by the granite as it would have existed at 2640 Ma. Thus, the metamorphic sequence, at its current level of exposure, can represent no more than a part of the protolith for the granite

  11. Determining heterogeneous deformation for granitic rocks in the northern thrust in Wadi Mubarak belt, Eastern Desert, Egypt

    Kassem, Osama M. K.

    2011-05-01

    Finite-strain was studied in the mylonitic granitic and metasedimentary rocks in the northern thrust in Wadi Mubarak belt to show a relationship to nappe contacts between the old granitic and metavolcano-sedimentary rocks and to shed light on the heterogeneous deformation for the northern thrust in Wadi Mubarak belt. We used the Rf/ϕ and Fry methods on feldspar porphyroclasts, quartz and mafic grains from 7 old granitic and 7 metasedimentary samples in the northern thrust in Wadi Mubarak belt. The finite-strain data shows that old granitic rocks were moderate to highly deformed and axial ratios in the XZ section range from 3.05 to 7.10 for granitic and metasedimentary rocks. The long axes (X) of the finite-strain ellipsoids trend W/WNW and E/ENE in the northern thrust in Wadi Mubarak belt. Furthermore, the short axes (Z) are subvertical associated with a subhorizontal foliation. The value of strain magnitudes mainly constants towards the tectonic contacts between the mylonitic granite and metavolcano-sedimentary rocks. The data indicate oblate strain symmetry (flattening strain) in the mylonitic granite rocks. It is suggested that the accumulation of finite strain was formed before or/and during nappe contacts. The penetrative subhorizontal foliation is subparallel to the tectonic contacts with the overlying nappes and foliation was formed during nappe thrusting.

  12. Uranium-lead age determinations on granitic rocks from the eastern Bushveld Complex

    Faurie, J.N.

    1978-08-01

    Uranium-lead age determinations were carried out on four types of granitic rocks from the eastern Bushveld Complex. The oldest rocks in the area are gneisses and felsites - 2604 plus minus 100 m.y. old - which form the centre of the Dennilton dome. The Rooiberg felsites could not be dated directly because of the absence of zircon, however a porphyritic granite sill, which shows intrusive relations with the Rooiberg felsites, was dated at 2090 plus minus 40 m.y., an age which can also be regarded as a minimum age for the Rooiberg felsites. No reliable age could be determined for the granophyres because of the large amount of lead-loss reflected in the zircon. The majority of zircons from these granophyres showed a peculiar hieroglyphic texture, a phenomena which has not yet been recorded in literature. The samples collected from the granites gave an age of 1950 plus minus 80 m.y. and thus form part of the Nebo Granite. Attempts have been made to obtain more concordant zircon ages throughout the present study. Although some success was achieved by analysing different size fractions of a zircon population, the non-magnetic fractions gave the most promising results [af

  13. A review of numerical techniques approaching microstructures of crystalline rocks

    Zhang, Yahui; Wong, Louis Ngai Yuen

    2018-06-01

    The macro-mechanical behavior of crystalline rocks including strength, deformability and failure pattern are dominantly influenced by their grain-scale structures. Numerical technique is commonly used to assist understanding the complicated mechanisms from a microscopic perspective. Each numerical method has its respective strengths and limitations. This review paper elucidates how numerical techniques take geometrical aspects of the grain into consideration. Four categories of numerical methods are examined: particle-based methods, block-based methods, grain-based methods, and node-based methods. Focusing on the grain-scale characters, specific relevant issues including increasing complexity of micro-structure, deformation and breakage of model elements, fracturing and fragmentation process are described in more detail. Therefore, the intrinsic capabilities and limitations of different numerical approaches in terms of accounting for the micro-mechanics of crystalline rocks and their phenomenal mechanical behavior are explicitly presented.

  14. Petrogenesis of Mesozoic granites in the Xitian, South China: Evidence from whole-rock geochemistry and zircon isotopes

    Liu, Q.; Sun, J.; He, M.; Hou, Q.; Niu, R.

    2017-12-01

    Mesozoic granitoids are widespread in southeastern China, which accompanied with lots of world-famous polymetallic deposits. The mineralization is believed to be related to the Mesozoic granitic magmatism. However, the petrogenesis of these granites and their relation to the mineralization are still debated. As a typical granitic pluton, Xitian granites from the eastern Hunan Province are formed during this period and associated with tungsten-tin deposit. Whole-rock geochemical, SIMS zircon geochronology and oxygen isotopes, as well as LA-ICPMS zircon Lu-Hf isotopic analyses, were carried out on a suite of rocks from Xitian granitic pluton to constrain their magmatic sources and petrogenesis. Xitian granitic pluton is mainly composed of biotite adamellite, biotite granite, fine-grained granite. SIMS and LA-ICPMS U-Pb dating of zircons indicate that there are two episodes of these rocks, i.e., Late Triassic granites (227-233Ma) and Late Jurassic granites (150-154Ma). The Xitian granites are silica-rich, potassic and weakly peraluminous. Petrographic and geochemical features show that they are highly fractionated I-type granites. The combined elemental and isotopic results indicated that the Late Triassic granite in Xitian area experienced a process of crystal fractionation of crustal-derived magmas coupled with strong assimilation of the surrounding rocks. The occurrence of Jurassic granitoids in Xitian area is attributed to ascending of mantle-derived magmas, which provide heat for partial melting of crustal materials. The Late Jurassic granite may be derived from juvenile crust or partial melting of ancient crustal rocks, whereas high degrees of crystal fractionation further enriched tungsten-tin in the evolved granitic rocks. This work was financially supported by the Research Cooperation between Institute and University of Chinese Academy of Sciences grant (Y552012Y00), Public Welfare Project of the Ministry of land and Resources of China (201211024

  15. An evaluation of hydrogeologic data of crystalline rock systems

    Raven, K.G.; Lafleur, D.W.

    1986-12-01

    This report presents a detailed review of hydrogeologic data collected as part of various research programs investigating fractured crystalline rock around the world. Based on the available information describing the test equipment, test methods and analytical techniques, the data have been assessed in terms of their reliability and representativeness, and likely error ranges have been assigned. The data reviewed include both hydrogeologic parameters, such as permeability, storage coefficient components (principally porosity), and fracture characteristic data

  16. Sorption of radionuclides from spent fuel in crystalline rocks

    Nikula, A.

    1982-10-01

    The safe disposal of spent nuclear fuel or reprocessed waste is an essential element in the expansion of the nuclear power industry. Stable rock formations e.g. granite are considered to be potential sites for disposal. A major factor in evaluating the degree of safety of the disposal is the sorption of radionuclides in rock, which affects their retardation. The report considers the chemical forms of the hazardous radionuclides of spent nuclear fuel in groundwater and the effects of the water's properties on them. In the groundwater near the Olkiluoto power plant site cesium, strontium and radium are in cationic form, iodine as I - . Technetium would occur as TcO +2 , but the pertechnetate form is also possible. Uranium most probably would be as U(VI) plutonium and neptunium as Np(IV) or Np(V). The valences for thorium, americium and curium are not changed in this groundwater and would be +4, +3 and +3, respectively. The actinides in groundwater are all in hydrated or complex form. An increase on the ionic stregth of the groundwater in most instances causes a decrease in the sorption of nuclides since the ion exchange capacity of the rock is limited. Anionic ligands also decrease sorption of cations by complex formation. In some case, on the other hand, high salt concentrations may cause formation of radiocolloids of lanthanides and neptunium and thus increase sorption. In all cases the degree of sorption described by the distribution ratio Ksub(d) was influenced by the pH of the groundwater. Sorption of cesium and strontium increased with growing pH. The sorption behaviour of actinides was in positive correlation with formation of hydroxide complexes at different pH values. The Ksub(d) values of Cs, Sr, Co, Ni and Am for Olkiluoto granites were found to agree with Swedish values, also determined at ambient atmospheric conditions

  17. The geochemistry of high-level waste disposal in granitic rocks

    Chapman, N.A.; Sargent, F.P.

    1984-01-01

    Under the auspices of the cooperative agreement between Euratom and Atomic Energy of Canada Ltd about radioactive waste management and disposal, a joint workshop was held on the topic of the geochemistry of high-level waste disposal in granitic rocks. The report covers (1) waste form leaching, (2) thermodynamics, (3) geochemical models, (4) the role of colloids, (5) sorption phenomena, (6) the linking of flow and geochemical models, (7) microbial activity

  18. Protocol proposal for radon concentration mensuration from granitic rocks in marble factory

    Del Claro, Flavia

    2016-01-01

    Naturally occurring radionuclides such as radon ( 222 Rn), its decay products and other elements from the radioactive series of uranium ( 238 U and 235 U) and thorium ( 232 Th) are an important source of human exposure to natural radioactivity. The worldwide evaluation of health radiobiological effects and risks from population exposure to natural radionuclides is a growing concern. Radionuclides such as radon ( 222 Rn), the thoron ( 220 Rn), radio ( 2 '2'6Ra), thorium ( 23 '2Th) and potassium ( 40 K) may occur in materials commonly used in construction of dwellings and buildings. Thus, the radioactivity from marbles and granites is of importance, so that under certain conditions these materials radioactivity levels can be hazardous requiring the implementation of mitigation measurements. This research presents a technical protocol marble factories for the control human exposure to natural radioactivity exhaled from granitic rocks. The protocol was based on measurements of the 222 Rn and 220 Rn concentration in Brazilian granite rocks commonly nationally and exported. The 222 Rn and 220 Rn measurements were done using the AlphaGUARD (Saphymo GmbH) and RAD7 (Durridge Company) apparatus, respectively. The samples of granite were sealed in glass jars for 40 days in to achieve secular equilibrium between 226 Ra and 222 Rn radionuclides. The measurements were performed on Applied Nuclear Physics Laboratory at the Federal Technological University of Parana. Also, solid-state nuclear track detectors CR-39 were installed in a marble factory environments located in Curitiba - Parana for the evaluation of 222 Rn concentrations in workplaces. The CR-39 detectors were exposed for about 90 days and submitted to etching process. The alpha particle tracks were observed using an optical microscope. Some granite samples analyzed presented 222 Rn concentrations of attention, since the average values ranged from 3 ± 1 Bq/m 3 to 2087 ± 19 Bq/m 3 . The results obtained

  19. Mechanisms of hydrothermal alteration in a granitic rock. Consequences for high-level radioactive waste disposal

    Parneix, J.C.

    1987-06-01

    The study of hydrothermal alteration in the Auriat granitic rock (France, Massif-Central) has evidenced three main events: - a pervasive chloritisation of biotites in some parts of the drill-core, - an alteration localized around subvertical cracks and superimposed on previously chloritized or unaltered granite, - an alteration localized around subhorizontal cracks cross-cutting the preceding ones. The second type of alteration, produced by a geothermal system, gives the most interesting results to be applied to the nuclear radwaste disposal problem. Among primary minerals of granite, only biotite (or chlorite) and oligoclase are intensively altered. Therefore, the chemical composition of these minerals induces the nature of secondary parageneses. These, associated to the subvertical cracks network, indicate a thermal gradient of 150 C/Km. The geochemical code has allowed to corroborate that the thermal gradient was responsible for the occurrence of different parageneses with depth. Moreover, it was shown that the variable mineralogy around cracks was due to a thermal profile established at equilibrium between the rock and the fluid. Therefore, the extent of the alteration was proportional to the thermal power of the fluid. A dissolution and next a precipitation phase of new minerals characterize hydrothermal alteration, which is due to the thermal power emitted by radioactive waste and linked with the evolution of temperature during time. This alteration provokes two favourable events to storage: decrease of rock porosity and increase of sorption capacity [fr

  20. Uranium in granites

    Maurice, Y.T.

    1982-01-01

    Recent research activities of the Canadian Uranium in Granites Study are presented in 18 papers and 3 abstracts. 'Granites' is used as a generic term for granitoids, granitic rocks, and plutonic rocks

  1. Between-hole acoustic surveying and monitoring of a granitic rock mass

    Paulsson, B.N.P.; King, M.S.

    1980-02-01

    The purpose of this technical note is to present preliminary results of an acoustic monitoring study performed as part of a comprehensive rock mechanic and geophysics research program (Ref.20) associated with large-scale heater tests in an abandoned iron-ore mine in central Sweden. The investigation was performed in a fractured granitic rock mass at a sub-surface depth of 340 m, in a drift adjacent to the original iron-ore mine workings. Acoustic monitoring took place between four empty, dry, vertical boreholes of 10 m depth spaced in the vicinity of a vertical heater borehole in the floor of a drift

  2. Characterization on the Fracture system in jurassic granitic rocks: Kosung and Yusung areas

    Kim, Kyung Su; Bae, Dae Seok; Kim, Chun Soo; Park, Byung Yoon; Koh, Yong Kweon

    2001-03-01

    The safety of waste disposal can be achieved by a complete isolation of radioactive wastes from biosphere or by a retardation of nuclide migration to reach an acceptable dose level. For the deep geological disposal of high-level radioactive waste, the potential pathways of nuclide primarily depend on the spatial distribution characteristics of conductive fractures in rock mass. Major key issues in the quantification of fracture system for a disposal site are involved in classification criteria, hydraulic parameters, geometry, field investigation methods etc. This research aims to characterize the spatial distribution characteristics of regional lineaments and background fractures in eastern and western-type granite rock mass.

  3. Characterization on the Fracture system in jurassic granitic rocks: Kosung and Yusung areas

    Kim, Kyung Su; Bae, Dae Seok; Kim, Chun Soo; Park, Byung Yoon; Koh, Yong Kweon

    2001-03-01

    The safety of waste disposal can be achieved by a complete isolation of radioactive wastes from biosphere or by a retardation of nuclide migration to reach an acceptable dose level. For the deep geological disposal of high-level radioactive waste, the potential pathways of nuclide primarily depend on the spatial distribution characteristics of conductive fractures in rock mass. Major key issues in the quantification of fracture system for a disposal site are involved in classification criteria, hydraulic parameters, geometry, field investigation methods etc. This research aims to characterize the spatial distribution characteristics of regional lineaments and background fractures in eastern and western-type granite rock mass

  4. REE enrichment in granite-derived regolith deposits of the southeast United States: Prospective source rocks and accumulation processes

    Foley, Nora K.; Ayuso, Robert A.; Simandl, G.J.; Neetz, M.

    2015-01-01

    The Southeastern United States contains numerous anorogenic, or A-type, granites, which constitute promising source rocks for REE-enriched ion adsorption clay deposits due to their inherently high concentrations of REE. These granites have undergone a long history of chemical weathering, resulting in thick granite-derived regoliths, akin to those of South China, which supply virtually all heavy REE and Y, and a significant portion of light REE to global markets. Detailed comparisons of granite regolith profiles formed on the Stewartsville and Striped Rock plutons, and the Robertson River batholith (Virginia) indicate that REE are mobile and can attain grades comparable to those of deposits currently mined in China. A REE-enriched parent, either A-type or I-type (highly fractionated igneous type) granite, is thought to be critical for generating the high concentrations of REE in regolith profiles. One prominent feature we recognize in many granites and mineralized regoliths is the tetrad behaviour displayed in REE chondrite-normalized patterns. Tetrad patterns in granite and regolith result from processes that promote the redistribution, enrichment, and fractionation of REE, such as late- to post- magmatic alteration of granite and silicate hydrolysis in the regolith. Thus, REE patterns showing tetrad effects may be a key for discriminating highly prospective source rocks and regoliths with potential for REE ion adsorption clay deposits.

  5. Patherns in the rare earth elements of the Serra do Carambei granite (Parana) and the others associated ignous rocks

    Pinto-Coelho, C.V.; Marini, O.J.

    1986-01-01

    The rare earth elements (REE) distribution patters in igneous rocks of the Serra do Carambei Granite area (Parana) were a very important tool to elucidate the genetic processes and the cogenetic relationships between these rocks. The porphyroid facies of the Cunhaporanga Granitoid Complex has a REE distribution pattern characterized by decreasing concentrations in direction to the heavy rare earth elements (HREE) and the smooth Eu negative anomalie, compatible with amphibole fractionation during the magma ascent and the incipient plagioclase fractionation. The REE pattern of the Serra do Carambei Granite is characterized by the strong Eu negative anomalie, by the light rare earth element (LREE) depletion and by the HREE increase. This shape of the REE patterns is frequently observed in Sn-W granites, according to French authors. However in the igneous rocks of the Serra do Carambei Granite area this is not true. ''Rhyolite'' dytes intrusives in the Serra do Carambei Granite exhibit REE pattern similar to the wall rock, indicating then the same genetic processes. The Castro Group rhyolites have REE patterns with decreasing concentrations in direction to the HREE and smooth Eu negative anomalie. The REE distribution patterns is against the consanguinity between the ''rhyolites'' intruded in the Serra do Carambei Granite and the rhyolites of the Castro Group and also between these rhyolites and the above mentioned Granite. (author) [pt

  6. Greenhouse Gases and Energy Intensity of Granite Rock Mining Operations in Thailand: A Case of Industrial Rock-Construction

    Kittipongvises Suthirat

    2016-12-01

    Full Text Available This paper is aimed to systematically assess greenhouse gases (GHGs and energy intensity of the granite rock mining operations in Thailand and also identify a range of feasible options to minimize their GHG emissions. Mining factories A, B and C, located in the Eastern region of Thailand, were selected as research case studies. The results indicated that the 3-year average of GHGs emissions from factories A to C was 3387 718 kgCO2e per year with approximately 2.92 kgCO2e per ton of granite rock produced over 2012 to 2014. Of this, the carbon intensity of grid-electricity consumption for the crushed rock production was 1.84 kgCO2/kWh. Diesel fuel combustion for transport activities in the mining factories was the greatest contributor to GHGs emissions (68 % compared to the purchased electricity and explosion process, with 31 % and 1 %, respectively. In-Pit Crushing and Conveying (IPCC installation, haul truck payload optimization and management, and reduction in tire rolling resistance have shown potential to reduce carbon emissions accounted for 20 % to 70 %.

  7. Greenhouse Gases and Energy Intensity of Granite Rock Mining Operations in Thailand: A Case of Industrial Rock-Construction

    Kittipongvises, Suthirat; Chavalparit, Orathai; Sutthirat, Chakkaphan

    2016-12-01

    This paper is aimed to systematically assess greenhouse gases (GHGs) and energy intensity of the granite rock mining operations in Thailand and also identify a range of feasible options to minimize their GHG emissions. Mining factories A, B and C, located in the Eastern region of Thailand, were selected as research case studies. The results indicated that the 3-year average of GHGs emissions from factories A to C was 3387 718 kgCO2e per year with approximately 2.92 kgCO2e per ton of granite rock produced over 2012 to 2014. Of this, the carbon intensity of grid-electricity consumption for the crushed rock production was 1.84 kgCO2/kWh. Diesel fuel combustion for transport activities in the mining factories was the greatest contributor to GHGs emissions (68 %) compared to the purchased electricity and explosion process, with 31 % and 1 %, respectively. In-Pit Crushing and Conveying (IPCC) installation, haul truck payload optimization and management, and reduction in tire rolling resistance have shown potential to reduce carbon emissions accounted for 20 % to 70 %.

  8. Radionuclide migration in fractured rock: hydrological investigations at an experimental site in the Carnmennellis granite, Cornwall

    Heath, M.J.; Durrance, E.M.

    1985-01-01

    The objectives, methods and results of hydrological investigation of the granite at an experimental site in Cornwall are described and discussed. Constant head injection tests and radioactive tracer experiments have revealed a fracture permeability in which water movement is confined to discrete fractures separated by rock of very low permeability. Data on flow path frequency, orientation and effective hydraulic aperture, required for network modelling, are presented for a 700 m borehole, with additional hydraulic data from three other boreholes. In addition to fractures of average hydraulic conductivity a small number of major hydraulic features (''main drains'') with major implications for radionuclide migration have been identified. A mean hydraulic conductivity for the granite investigated of 1.57x10 -7 ms -1 has been obtained, 2.11x10 -8 ms -1 if the major hydraulic features are excluded

  9. Geochemical studies of granitic rocks of Kallur area, Manvi Taluk, Raichur district, Karnataka (India).

    Raghavendra, N R; Reddy, R Purushottam; Nijagunappa, R

    2011-01-01

    The geochemical data is much widely used in establishing the overall chemical relation existing between the different rock types with their parentage. A major impetus for this shift comes not only from the need to understand and quantify better the spatial and temporal evolution, with emphasis on the younger greenstone belts (Kallur copper formations), but also from the recognition that such knowledge could form the basis for the sustainable development of our natural resources. In addition, the recurrence of natural hazards has reinforced the need to learn more about the mechanics and to develop predictive modeling with advanced technical tools. This paper is emphasizing on Granodiorites of Kallur area of Manvi Taluk, Raichur District to substantiate the classical approaches of exploration and data gathering through quantitative methods of data processing and interpretation. The trilinear diagram indicates that the granites are rich in Potash and Soda. This clearly indicates that Granites are fairly rich in K2O than Na2O.

  10. Evaluation of natural radioactivity in some granitic rocks in the state of Parana, Brazil and its use in civil construction

    Ferreira, Ademar de Oliveira

    2013-01-01

    Primordial, or terrestrial natural radionuclides, are found in different amounts in the environment. In dwellings, an important dose increment is due to building materials, which contribute for both the external gamma dose from the radionuclides of the 238 U, 235 U and 232 Th series and the natural 40 K and the internal dose, due mainly to 222 Rn inhalation. Once granitic rocks are widely used both as construction materials or structural flooring, those rocks can become an important dose source, depending on the content of concentrations of radioactivity, and the construction application. In this work, a database for granitic rocks of the crystalline shield of Parana (mainly in the Metropolitan Region of Curitiba, RMC), used in civil construction, was generated, evaluating in terms of radiological protection the external and internal dose increments, caused by the use of these materials. Also, possible correlations between the 226 Ra activity concentration, the 222 Rn exhalation rate, density, porosity and chemical composition (oxide content) in these samples had been studied. The external dose was assessed by gamma-ray spectrometry with High-Purity Germanium detectors, where the activity concentration of the radionuclides 232 Th, 226 Ra and 40 K are the parameters used in dosimetric models (Dosimetric Indexes), which established limits in accordance with the form, amount and application of material of construction. For the calculation of the annual effective external dose it was assumed a room model with dimensions of 4 m x 5 m x 2:8 m and all walls internally covered with 2 cm thickness of granite and an annual exposure time of 7000 h as suggested by the European Commission of Radiological Protection for internal superficial coating materials. The internal exposure was assessed from the radon concentration in the air of the room model, simulated from the superficial exhalation rate of 222 Rn. The exhalation rate was determined by the passive detection technique

  11. Exploring deep potential aquifer in water scarce crystalline rocks

    out to explore deep groundwater potential zone in a water scarce granitic area. As existing field condi- ... Decision support tool developed in granitic ter- .... cially in terms of fracture system, the aquifer char- acteristics ... Methodologies used.

  12. Study on Kalimantan uranium province: The assessment on uranium mineralization of metamorphic and granitic rocks at Schwaner mountains

    Tjokrokardono, Soeprapto

    2002-01-01

    Uranium exploration activities done by CEA-BATAN had discovered uranium occurrences as the radiometric and uranium content anomalies at metamorphic and granite rocks of Schwaner Mountains, Kalimantan. A part of the occurrences on metamorphic rocks at Kalan basin has been evaluated and be developed onto follow-up step of prospecting by construction of some drilling holes and an exploration adit. In order to increase the national uranium resources, it is necessarily to extent the exploration activity to out side or nearby of Kalan basin. The goal of this assessment is to understand the uranium accumulation mechanism at Pinoh metamorphic rocks of Kalan Kalimantan and to delineate areas that uranium may exist. The assessment was based on the aspect of geology, anomaly of radioactivity and uranium contents, tectonics and alterations. Pinoh metamorphic rocks which is influenced by Sukadana granite intrusion are the high potential rocks for the uranium accumulation, because the intrusion contains a relatively high of U, Th, Cu, Zn, Nb, Mn, and W. The potential rock distributions are in between G. Ransa granite intrusion at the east and Kotabaru granite intrusions at the west. The mineralizations are categorized as vein type deposits of granitic association

  13. Rb-Sr ages and initial 87Sr/86Sr ratios of late paleozoic granitic rocks from northern Chile

    Shibata, Ken; Ishihara, Shunso; Ulriksen, C.E.

    1984-01-01

    Rb-Sr whole-rock isochron ages were determined on three suites of so-called Paleozoic granitic rocks from northern coastal Chile. The granitic rocks from the Valparaiso and Ci Funcho areas are dated as 296.3 +- 5.4 Ma and 262.2 +- 4.6 Ma, respectively, which are in accord with geologically estimated age. The rocks from the Chanaral area is dated as 212.8 +- 8.6 Ma, which is correlated close to the Triassic-Jurassic boundary age. A K-Ar age of 196 +- 6 Ma was obtained on biotite in granite from Esmeralda between Ci Funcho and Chanaral. These age results demonstrate that no Precambrian plutonism occurred in the studied area, and that so-called Paleozoic granitic rocks in the Ci Funcho-Chanaral area are divided into Permian and early Mesozoic in age. Initial 87 Sr/ 86 Sr ratios of the ilmenite-series granitic rocks from the coastal region are 0.70641 (Valparaiso), 0.70635 (Ci Funcho) and 0.70455 (Chanaral). These relatively low ratios deny substantial crustal contribution to the granitoids. The initial ratios of magnetite-series granitoids from porphyry- and manto-type mineralized areas (Chiquicamata, El Salvador and Tocopilla) are as low as 0.70344 to 0.70464. (author)

  14. Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 5. Baseline rock properties-granite

    1978-04-01

    This volume, Y/OWI/TM-36/5, Baseline Rock Properties--Granite, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. This report, on the rock properties of typical granites, includes an evaluation of the various test results reported in the literature. Firstly, a literature survey was made in order to obtain a feel for the range of rock properties encountered. Then, granites representative of different geologic ages and from different parts of the United States were selected and studied in further detail. Some of the special characteristics of granite, such as anisotropy, creep and weathering were also investigated. Lastly, intact properties for a typical granite were selected and rock mass properties were derived using appropriate correction factors

  15. Mobilities of radionuclides in fresh and fractured crystalline rock

    Torstenfelt, B.; Ittner, T.; Allard, B.; Andersson, K.; Olofsson, U.

    1982-12-01

    Sorption and migration of technetium, cesium and americium on fracture surfaces and fresh surfaces of granites taken from drilling cores from the Finnsjoen and Studsvik areas and the Stripa mine are reported. The three elements were used as reference elements with different chemistry and behaviour in water; under the conditions used in the experiments technetium exists as the heptavalent TcO -4 -ion, cesium as the non-complexed monovalent cation Cs + and americium as the strongly hydrolysed Am(OH)super (3-x) (x-1-4). The waters used were synthetic groundwaters representative of waters from the drilling holes. After the exposure of the fracture samples to spiked groundwater solutions for a period of three up to six months the penetration depths and concentration profiles were analysed and autoradiographs of cesium and americium distribution vs depth were taken. The sorption of technetium was found to be negligible. The transport of TcO -4 depends on accessibility to fractures and micro-fissures in the rock. Cesium is sorbed through an ion-exchange process. Migration of cesium depends not only on the transport in water into fractures and micro-fissures, but also on migration through mineral veins with a high CEC. Americium is strongly sorbed on most solid surfaces and did not migrate significantly during the contact time of three months. The diffusivity in granite was found to be around 10 - 13 m 2 /s for cesium; preliminary values for technetium and americium were 10 - 12 m 2 /s and less than 10 - 16 m 2 /s, respectively. (Authors)

  16. Assessment of the Alteration of Granitic Rocks and its Influence on Alkalis Release

    Ferraz, Ana Rita; Fernandes, Isabel; Soares, Dora; Santos Silva, António; Quinta-Ferreira, Mário

    2017-12-01

    Several concrete structures had shown signs of degradation some years after construction due to internal expansive reactions. Among these reactions there are the alkali-aggregate reactions (AAR) that occur between the aggregates and the concrete interstitial fluids which can be divided in two types: the alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR). The more common is the ASR which occurs when certain types of reactive silica are present in the aggregates. In consequence, an expansive alkali-silica gel is formed leading to the concrete cracking and degradation. Granites are rocks composed essentially of quartz, micas and feldspars, the latter being the minerals which contain more alkalis in their structure and thus, able to release them in conditions of high alkalinity. Although these aggregates are of slow reaction, some structures where they were applied show evidence of deterioration due to ASR some years or decades after the construction. In the present work, the possible contribution of granitic aggregates to the interstitial fluids of concrete by alkalis release was studied by performing chemical attack with NaOH and KOH solutions. Due to the heterogeneity of the quarries in what concerns the degree of alteration and/or fracturing, rock samples with different alteration were analysed. The alteration degree was characterized both under optical microscope and image analysis and compared with the results obtained from the chemical tests. It was concluded that natural alteration reduces dramatically the releasable alkalis available in the rocks.

  17. Disposal of radioactive waste in Swedish crystalline rocks

    Greis Dahlberg, Christina; Wikberg, Peter

    2015-01-01

    SKB, Swedish Nuclear Fuel and Waste Management Company is tasked with managing Swedish nuclear and radioactive waste. Crystalline rock is the obvious alternative for deep geological disposal in Sweden. SKB is, since 1988, operating a near surface repository for short-lived low and intermediate-level waste, SFR. The waste in SFR comprises operational and decommissioning waste from nuclear plants, industrial waste, research-related waste and medical waste. Spent nuclear fuel is currently stored in an interim facility while waiting for a license to construct a deep geological repository. The Swedish long-lived low and intermediate-level waste consists mainly of BWR control rods, reactor internals and legacy waste from early research in the Swedish nuclear programs. The current plan is to dispose of this waste in a separate deep geological repository, SFL, sometimes after 2045. Understanding of the rock properties is the basis for the design of the repository concepts. Swedish crystalline rock is mechanical stable and suitable for underground constructions. The Spent Fuel Repository is planned at approximately 500 meters depth in the rock at the Forsmark site. The host rock will keep the spent fuel isolated from human and near-surface environment. The rock will also provide the stable chemical and hydraulic conditions that make it possible to select suitable technical barriers to support the containment provided by the rock. A very long lasting canister is necessary to avoid release and transport of radionuclides through water conducting fractures in the rock. A canister designed for the Swedish rock, consists of a tight, 5 cm thick corrosion barrier of copper and a load-bearing insert of cast iron. To restrict the water flow around the canister and by that prevent fast corrosion, a bentonite buffer will surround the canister. Secondary, the bentonite buffer will retard a potential release by its strong sorption of radionuclides. The SFR repository is situated in

  18. Disposal of radioactive waste in Swedish crystalline rocks

    Greis Dahlberg, Christina; Wikberg, Peter [Svensk Kaernbraenslehantering AB, Stockholm (Sweden)

    2015-07-01

    SKB, Swedish Nuclear Fuel and Waste Management Company is tasked with managing Swedish nuclear and radioactive waste. Crystalline rock is the obvious alternative for deep geological disposal in Sweden. SKB is, since 1988, operating a near surface repository for short-lived low and intermediate-level waste, SFR. The waste in SFR comprises operational and decommissioning waste from nuclear plants, industrial waste, research-related waste and medical waste. Spent nuclear fuel is currently stored in an interim facility while waiting for a license to construct a deep geological repository. The Swedish long-lived low and intermediate-level waste consists mainly of BWR control rods, reactor internals and legacy waste from early research in the Swedish nuclear programs. The current plan is to dispose of this waste in a separate deep geological repository, SFL, sometimes after 2045. Understanding of the rock properties is the basis for the design of the repository concepts. Swedish crystalline rock is mechanical stable and suitable for underground constructions. The Spent Fuel Repository is planned at approximately 500 meters depth in the rock at the Forsmark site. The host rock will keep the spent fuel isolated from human and near-surface environment. The rock will also provide the stable chemical and hydraulic conditions that make it possible to select suitable technical barriers to support the containment provided by the rock. A very long lasting canister is necessary to avoid release and transport of radionuclides through water conducting fractures in the rock. A canister designed for the Swedish rock, consists of a tight, 5 cm thick corrosion barrier of copper and a load-bearing insert of cast iron. To restrict the water flow around the canister and by that prevent fast corrosion, a bentonite buffer will surround the canister. Secondary, the bentonite buffer will retard a potential release by its strong sorption of radionuclides. The SFR repository is situated in

  19. An in situ test of vibrating wire stressmeters in granitic rock

    Spinney, M.H.

    1990-02-01

    An in situ test was conducted to assess the ability of vibrating-wire stressmeters to measure stress changes in hard, unfractured granitic rock at the Underground Research Laboratory (URL). Twelve vibrating-wire stressmeters installed ahead of the face and below floor grade of Room 205 were monitored during the excavation of Room 205. The results were compared with results from CSIRO hollow inclusion triaxial strain cells, USBM boreholes deformation gauge overcore tests done before and after excavation, and a two-dimensional numerical model

  20. A study on the characteristics of site-scale fracture system in granite and volcanic rock

    Kim, Kyung Su; Kim, Chun Soo; Bae, Dae Seok; Park, Byoung Yoon; Koh, Young Kown [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-03-01

    The safety of waste disposal can be achieved by a complete isolation of radioactive wastes from biosphere or by a retardation of nuclide migration to reach an acceptable dose level. For the deep geological disposal of high-level radioactive waste, the potential pathways of nuclide primarily depend on the spatial distribution characteristics of conductive fractures. Major key issues in the quantification of fracture system for a disposal site are involved in classification criteria, hydraulic parameters, geometry, field investigation methods etc. This research aims to characterize the spatial distribution characteristics of conductive fractures in granite and volcanic rock mass. 10 refs., 32 figs., 13 tabs. (Author)

  1. Porosity measurements of crystalline rocks by laboratory and geophysical methods

    Alexander, J.; Hall, D.H.; Storey, B.C.

    1981-12-01

    Porosity values of igneous and metamorphic crystalline rocks have been determined from core samples taken at specific depths from Altnabreac, by a combination of laboratory and geophysical techniques. Using resaturation and mercury injection methods in three laboratories within I.G.S., porosity values have been derived and the effect of variations in the measuring techniques and results obtained have been compared. Comparison of inter-laboratory porosity values illustrates that systematic errors are present, resulting in higher porosity values for samples subjected to re-testing. This is considered to be caused by the variable nature of the initial samples combined with the inability to completely dry or resaturate samples during a second testing. Geophysical techniques for determining in situ porosity using the neutron log have been carried out in borehole ALA. The neutron log has been calibrated with laboratory derived porosity values and an empirical formula derived enabling porosity values to be ascribed throughout the logged borehole ALA. Comparison of the porosity results from Altnabreac with crystalline samples elsewhere in America, Europe and the U.K. suggest that porosities at Altnabreac are lower than average. However, very few publications concerned with water movement in crystalline areas actually state the method used. (author)

  2. Geological and rock mechanics aspects of the long-term evolution of a crystalline rock site

    Cosgrove, J.W.; Hudson, J.A.

    2009-01-01

    We consider the stability of a crystalline rock mass and hence the integrity of a radioactive waste repository contained therein by, firstly, identifying the geological evolution of such a site and, secondly, by assessing the likely rock mechanics consequences of the natural perturbations to the repository. In this way, the potency of an integrated geological-rock mechanics approach is demonstrated. The factors considered are the pre-repository geological evolution, the period of repository excavation, emplacement and closure, and the subsequent degradation and natural geological perturbations introduced by glacial loading. It is found that the additional rock stresses associated with glacial advance and retreat have a first order effect on the stress magnitudes and are likely to cause a radical change in the stress regime. There are many factors involved in the related geosphere stability and so the paper concludes with a systems diagram of the total evolutionary considerations before, during and after repository construction. (authors)

  3. Characterizing fractures and shear zones in crystalline rock using seismic and GPR methods

    Doetsch, Joseph; Jordi, Claudio; Laaksonlaita, Niko; Gischig, Valentin; Schmelzbach, Cedric; Maurer, Hansruedi

    2016-04-01

    Understanding the natural or artificially created hydraulic conductivity of a rock mass is critical for the successful exploitation of enhanced geothermal systems (EGS). The hydraulic response of fractured crystalline rock is largely governed by the spatial organization of permeable fractures. Defining the 3D geometry of these fractures and their connectivity is extremely challenging, because fractures can only be observed directly at their intersections with tunnels or boreholes. Borehole-based and tunnel-based ground-penetrating radar (GPR) and seismic measurements have the potential to image fractures and other heterogeneities between and around boreholes and tunnels, and to monitor subtle time-lapse changes in great detail. We present the analysis of data acquired in the Grimsel rock laboratory as part of the In-situ Stimulation and Circulation (ISC) experiment, in which a series of stimulation experiments have been and will be performed. The experiments in the granitic rock range from hydraulic fracturing to controlled fault-slip experiments. The aim is to obtain a better understanding of coupled seismo-hydro-mechanical processes associated with high-pressure fluid injections in crystalline rocks and their impact on permeability creation and enhancement. GPR and seismic data have been recorded to improve the geological model and characterize permeable fractures and shear zones. The acquired and processed data include reflection GPR profiles measured from tunnel walls, single-borehole GPR images, and borehole-to-borehole and tunnel-to-tunnel seismic and GPR tomograms. The reflection GPR data reveal the geometry of shear zones up to a distance of 30 m from the tunnels and boreholes, but the interpretation is complicated by the geometrical ambiguity around tunnels and boreholes and by spurious reflections from man-made structures such as boreholes. The GPR and seismic traveltime tomography results reveal brittle fractured rock between two ductile shear zones. The

  4. Experimental early crystallization of K-feldspar in granitic systems. Implications on the origin of magmatic fabrics in granitic rocks

    Díaz-Alvarado, J.

    2017-07-01

    One of the most outstanding characteristics of some granodioritic to granitic rocks is the presence of K-feldspar megacrysts. For instance, granodiorites and monzogranites of the Spanish Central System batholith present variable amounts of large (up to 10cm in length) euhedral K-feldspar crystals. The porphyritic textures, the euhedral shape, the alignment of plagioclase and biotite inclusions and the magmatic fabrics point to a magmatic origin for these megacrysts. This work presents a phase equilibria study in a high-K2O granodioritic system. A series of experiments were conducted with a granodioritic composition (GEMbiot) to study the crystallization sequence at the emplacement conditions in the Gredos massif, i.e. 4 H2O wt.% and 0.4GPa. Experimental results show that orthopiroxene is the liquidus phase at 1010ºC, which reacts with the H2O-rich melt to stabilize biotite between 980 and 940ºC. Plagioclase crystallizes at around 910ºC, and K-feldspar crystallizes in the matrix between 750 and 700ºC when the crystal fraction is around 0.5. However, at 850 ºC, a pelite-doped experiment shows euhedral K-feldspar (≈5vol%) in both the reactive xenolith domain together with cordierite and the granodioritic domain, where the K2O wt.% rise from 4.5 in the normal experiment to 5.9 in the doped experiment. These results suggest that the bulk-assimilation process promotes the bulk and heterogeneous K2O enrichment in a huge granodioritic magma volume, which triggers an early crystallization of K-feldspar megacrysts. Because of this early crystallization of the megacrysts, the magmatic foliations defined by K-feldspar megacrysts are formed during and after the emplacement processes and are highly influenced by tectonic kinematics.

  5. Temporal evolution of a granitic rock under thermal loads generated by fission products

    Ventura, M.A.; Ferreri, J.C.

    1985-01-01

    The thermal time history of a granitic mass under thermal loads, generated by the terminal subproducts arising from the Argentine nuclear programme is analyzed. This rock will be the final repository of those subproducts. The analysis is based on the consideration of a representative unit cell of the rock's centre using the Heating 5 programme. A preliminary analysis is made in order to obtain criteria with respect to the accuracy of the problem. Temporal evolution curves of the temperature on zones of interest of the unit cell considered are shown. Under the thermal loads considered, 500W by container, a maximum temperature of 55 deg C at the wall of the orifice subproducts' deposit is obtained. (Author) [es

  6. Search for underground openings for in situ test facilities in crystalline rock

    Wollenberg, H.A.; Strisower, B.; Corrigan, D.J.; Graf, A.N.; O' Brien, M.T.; Pratt, H.; Board, M.; Hustrulid, W.

    1980-01-01

    With a few exceptions, crystalline rocks in this study were limited to plutonic rocks and medium to high-grade metamorphic rocks. Nearly 1700 underground mines, possibly occurring in crystalline rock, were initially identified. Application of criteria resulted in the identification of 60 potential sites. Within this number, 26 mines and 4 civil works were identified as having potential in that they fulfilled the criteria. Thirty other mines may have similar potential. Most of the mines identified are near the contact between a pluton and older sedimentary, volcanic and metamorphic rocks. However, some mines and the civil works are well within plutonic or metamorphic rock masses. Civil works, notably underground galleries associated with pumped storage hydroelectric facilities, are generally located in tectonically stable regions, in relatively homogeneous crystalline rock bodies. A program is recommended which would identify one or more sites where a concordance exists between geologic setting, company amenability, accessibility and facilities to conduct in situ tests in crystalline rock.

  7. Search for underground openings for in situ test facilities in crystalline rock

    Wollenberg, H.A.; Strisower, B.; Corrigan, D.J.; Graf, A.N.; O'Brien, M.T.; Pratt, H.; Board, M.; Hustrulid, W.

    1980-01-01

    With a few exceptions, crystalline rocks in this study were limited to plutonic rocks and medium to high-grade metamorphic rocks. Nearly 1700 underground mines, possibly occurring in crystalline rock, were initially identified. Application of criteria resulted in the identification of 60 potential sites. Within this number, 26 mines and 4 civil works were identified as having potential in that they fulfilled the criteria. Thirty other mines may have similar potential. Most of the mines identified are near the contact between a pluton and older sedimentary, volcanic and metamorphic rocks. However, some mines and the civil works are well within plutonic or metamorphic rock masses. Civil works, notably underground galleries associated with pumped storage hydroelectric facilities, are generally located in tectonically stable regions, in relatively homogeneous crystalline rock bodies. A program is recommended which would identify one or more sites where a concordance exists between geologic setting, company amenability, accessibility and facilities to conduct in situ tests in crystalline rock

  8. Information collection regarding geoscientific monitoring techniques during closure of underground facility in crystalline rock

    Hosoya, Shinichi; Yamashita, Tadashi; Iwatsuki, Teruki; Saegusa, Hiromitsu; Onoe, Hironori; Ishibashi, Masayuki

    2016-01-01

    The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite) at Mizunami City in Gifu Prefecture, central Japan. On the occasion of the reform of the entire JAEA organization in 2014, JAEA identified the critical issues on the geoscientific research program: “Development of modelling technologies for mass transport”, “Development of drift backfilling technologies” and “Development of technologies for reducing groundwater inflow”, based on the latest results of the synthesizing R and D. The purposes of the “Development of drift backfilling technologies” are to develop closure methodology and technology, and long-term monitoring technology, and to evaluate resilience of geological environment. In order to achieve the purposes, previous information from the case example of underground facility constructed in crystalline rock in Europe has been collected in this study. In particular, the boundary conditions for the closure, geological characteristics, technical specifications, and method of monitoring have been focused. The information on the international project regarding drift closure test and development of monitoring technologies has also been collected. In addition, interviews were conducted to Finnish and Swedish specialists who have experiences involving planning, construction management, monitoring, and safety assessment for the closure to obtain the technical knowledge. Based on the collected information, concept and point of attention, which are regarding drift closure testing, and planning, execution management and monitoring on the closure of MIU, have been specified. (author)

  9. A seismic study on cracks in crystalline rock

    Israelsson, H.

    1981-07-01

    This report summarizes results from a field study with in-situ seismic measurements in crystalline rock. It was found that among a few potential seismic techniques the so called cross hole method would probably provide the most powerful capability for detecting cracks and fracture zones. By this method the area between two holes are systematically scanned by seismic raypaths. Seismic signals are generated in one hole by micro explosions and recorded in the other at various combinations of depths. A test sample of scanning data showed a rather dramatic variation of the seismic P-wave velocity (5-6 km/s). Analysis procedures like tomographic imaging was applied to this data set primarily to illustrate the kind of structural mapping such procedures can provide. (Author)

  10. Research on isotope geology. Assessment of heat production potential of granitic rocks and development of geothermal exploration techniques using radioactive/stable isotopes and fission track 2

    Shin, Seong Cheon; Chi, Se Jung [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

    1995-12-01

    Radioelements and heat production rates of granitic rocks and stable isotopes of groundwaters were analyzed to investigate the geothermal potential of Wolchulsan granite complex in the southern Yeongam area. Wolchulsan granite complex is composed mainly by Cretaceous pink alkali-feldspar granite and partly Jurassic biotite granite. The main target for the geothermal exploration is the alkali-feldspar granite that is known in general to be favorable geothermal reservoir(e.g., Shap granite in UK). To develop exploration techniques for geothermal anomalies, all geochemical data were compared to those from the Jeonju granite complex. Heat production rates(HPR) of the alkali-feldspar granite is 1.8 - 10.6 {mu}Wm{sup -3}. High radio-thermal anomalies were revealed from the central western and northern parts of the granite body. These are relatively higher than the Caledonian hot dry granites in the UK. The integrated assessment of Wolchulsan granite complex suggests potential of the Cretaceous alkali-feldspar granite as a geothermal targets. Groundwater geochemistry of the Yeongam area reflects simple evaporation process and higher oxidation environment. Stable isotope data of groundwaters are plotted on or close to the Meteoric Water Line(MWL). These isotopic data indicate a significant meteoric water dominance and do not show oxygen isotope fractionation between groundwater and wall rocks. In despite of high HPR values of the Yeongam alkali-feldspar granite, groundwater samples do not show the same geochemical properties as a thermal water in the Jeonju area. This reason can be well explained by the comparison with geological settings of the Jeonju area. The Yeongam alkali-feldspar granite does not possess any adjacent heat source rocks despite its high radio-thermal HPR. While the Jeonju granite batholith has later heat source intrusive and suitable deep fracture system for water circulation with sedimentary cap rocks. (Abstract Truncated)

  11. Dynamic rock tensile strengths of Laurentian granite: Experimental observation and micromechanical model

    Kaiwen Xia

    2017-02-01

    Full Text Available Tensile strength is an important material property for rocks. In applications where rocks are subjected to dynamic loads, the dynamic tensile strength is the controlling parameter. Similar to the study of static tensile strength, there are various methods proposed to measure the dynamic tensile strength of rocks. Here we examine dynamic tensile strength values of Laurentian granite (LG measured from three methods: dynamic direct tension, dynamic Brazilian disc (BD test, and dynamic semi-circular bending (SCB. We found that the dynamic tensile strength from direct tension has the lowest value, and the dynamic SCB gives the highest strength at a given loading rate. Because the dynamic direct tension measures the intrinsic rock tensile strength, it is thus necessary to reconcile the differences in strength values between the direct tension and the other two methods. We attribute the difference between the dynamic BD results and the direct tension results to the overload and internal friction in BD tests. The difference between the dynamic SCB results and the direct tension results can be understood by invoking the non-local failure theory. It is shown that, after appropriate corrections, the dynamic tensile strengths from the two other tests can be reduced to those from direct tension.

  12. Reconstruction of crustal blocks of California on the basis of initial strontium isotopic compositions of Mesozoic granitic rocks

    Kistler, Ronald Wayne; Peterman, Zell E.

    1978-01-01

    Initial 87Sr/ 86 Sr was determined for samples of Mesozoic granitic rocks in the vicinity of the Garlock fault zone in California. These data along with similar data from the Sierra Nevada and along the San Andreas fault system permit a reconstruction of basement rocks offset by the Cenozoic lateral faulting along both the San Andreas and Garlock fault systems. The location of the line of initial 87Sr/ 86 Sr = 0.7060 can be related to the edge of the Precambrian continental crust in the western United States. Our model explains the present configuration of the edge of Precambrian continental crust as the result of two stages of rifting that occurred about 1,250 to 800 m.y. ago, during Belt sedimentation, and about 600 to 350 m.y. ago, prior to and during the development of the Cordilleran geosyncline and to left-lateral translation along a locus of disturbance identified in the central Mojave Desert. The variations in Rb, Sr, and initial 87Sr/ 86 Sr of the Mesozoic granitic rocks are interpreted as due to variations in composition and age of the source materials of the granitic rocks. The variations of Rb, Sr, and initial 87Sr/ 86 Sr in Mesozoic granitic rocks, the sedimentation history during the late Precambrian and Paleozoic, and the geographic position of loci of Mesozoic magmatism in the western United States are related to the development of the continental margin and different types of lithosphere during rifting.

  13. Major and minor elements and traces in igneous rocks from crystalline basement of Parana by X-ray fluorescence

    Ferreira, Ademar O.; Pecequilo, Brigitte R.S.; Scapin, Marcos A.; Salvador, Vera L.R.

    2015-01-01

    Major and minor components of 30 acid and basic igneous rocks (granites, syenites, riolites and a basalt) of the Parana state crystalline basement were determined by X-ray fluorescence spectrometry (WDXRF), in order to evaluate the similarity in terms of the compositional content. The corrections of interelements effects (absorption/intensification) were performed by means of the fundamental parameters (FP) method. The methodology was validated using a certificated reference material. The main oxides found associated with the quantified elements are SiO_2, Al_2O_3, Na_2O, K_2O, Fe_2O_3, CaO, MgO, TiO_2, P_2O_5, MnO, SO_3, NiO, ZnO, Rb_2O. Through statistical analysis, the studied samples were organized in 3 groups of similar compositions: syenites, light granites and basalt and dark granites. The results show that the WDXRF technique is a robust tool that enables distinction even between similar geological samples. (author)

  14. Geotechnical assessment and instrumentation needs for isolation of nuclear waste in crystalline rocks: symposium proceedings

    Ubbes, W.F.; Duguid, J.O.

    1985-09-01

    On October 15-19, 1984, the Geotechnical Assessment and Instrumentation Needs (GAIN) Symposium was convened to examine the status of technology for the isolation of nuclear waste in crystalline rock. The objective of the 1984 GAIN Symposium was to provide technical input to the Crystalline Repository Project concerning: critical issues and information needs associated with development and assessment of a repository in crystalline rock; appropriate techniques and instrumentation for determining the information needed; and technology required to provide the measurement techniques and instrumentation for application in an exploratory shaft in crystalline rock. The findings and recommendations of the symposium are presented in these proceedings

  15. Geologic columns for the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure: Impactites and crystalline rocks, 1766 to 1096 m depth

    Horton, J. Wright; Gibson, R.L.; Reimold, W.U.; Wittmann, A.; Gohn, G.S.; Edwards, L.E.

    2009-01-01

    The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville drill cores from the Chesapeake Bay impact structure provide one of the most complete geologic sections ever obtained from an impact structure. This paper presents a series of geologic columns and descriptive lithologic information for the lower impactite and crystalline-rock sections in the cores. The lowermost cored section (1766-1551 m depth) is a complex assemblage of mica schists that commonly contain graphite and fibrolitic sillimanite, intrusive granite pegmatites that grade into coarse granite, and local zones of mylonitic deformation. This basement-derived section is variably overprinted by brittle cataclastic fabrics and locally cut by dikes of polymict impact breccia, including several suevite dikes. An overlying succession of suevites and lithic impact breccias (1551-1397 m) includes a lower section dominated by polymict lithic impact breccia with blocks (up to 17 m) and boulders of cataclastic gneiss and an upper section (above 1474 m) of suevites and clast-rich impact melt rocks. The uppermost suevite is overlain by 26 m (1397-1371 m) of gravelly quartz sand that contains an amphibolite block and boulders of cataclasite and suevite. Above the sand, a 275-m-thick allochthonous granite slab (1371-1096 m) includes gneissic biotite granite, fine- and medium-to-coarse-grained biotite granites, and red altered granite near the base. The granite slab is overlain by more gravelly sand, and both are attributed to debris-avalanche and/or rockslide deposition that slightly preceded or accompanied seawater-resurge into the collapsing transient crater. ?? 2009 The Geological Society of America.

  16. Hydrogen isotope ratios of clay minerals constituting clay veins found in granitic rocks in Hiroshima Prefecture

    Kitagawa, Ryuji; Kakitani, Satoru; Kuroda, Yoshimatsu; Matsuo, Sadao; Suzuoki, Tetsuro.

    1980-01-01

    The deuterium content of the constitutional and interlayer water extracted from the clay minerals (illite, montmorillonite, interstratified illite-montmorillonite mineral, kaolinite, halloysite) constituting the clay veins found in the granitic rocks in Hiroshima Prefecture was measured. The clay minerals were heated at 270 deg C to extract the interlayer water, then heated to 1,400 or 1,500 deg C to extract the constitutional water. The deuterium content of the local surface water collected from sampling points was measured. In the clay veins formed along perpendicular joints, the constituent clay minerals change from lower to upper part: illite → montmorillonite → kaolinite → halloysite. The deuterium content values of the constitutional water for illite and montmorillonite were estimated to be -67 to -69% and -86 to -89%, respectively. The deuterium content values of the constitutional water for halloysite range from -68 to -80% and for kaolinite from -63 to -67%. (J.P.N.)

  17. Formation of chemical gardens on granitic rock. A new type of alteration for alkaline systems

    Satoh, Hisao [Mitsubishi Materials Corporation, Naka (Japan). Energy Project and Technology Center; Tsukamoto, Katsuo [Tohoku Univ. Aramaki, Sendai (Japan). Dept. of Earth and Planetary Materials Science; Garcia-Ruiz, Juan Manuel [Granada Univ., Armilla (Spain). Lab. de Estudios Cristalograficos

    2014-06-15

    In order to understand the groundwater flow at near-underground facilities such as waste repositories, we have studied the effects of flowing an alkaline solution leached from cementitious building materials through the fractures of low-porosity granitic rocks under laboratory conditions. The results show that silica released from the dissolution of sodium-rich plagioclase and quartz reacts with the calcium leached from cementitious buildings to form calcium silicate hydrates (C-S-H) phases in the form of hollow tubular structures. These tubular structures form selectively on the surface of plagioclase in a similar way to reverse silica gardens structures. It was found that the rate of precipitation of C-S-H phases is faster than the rate of dissolution of plagioclase. This selftriggered dissolution/precipitation phenomenon may be an important factor controlling groundwater permeation in natural alkaline underground systems.

  18. Geohydrology of the climax stock granite and surrounding rock formations, NTS

    Murray, W.A.

    1981-05-01

    The location of the water table and the degree of saturation of the granitic rocks in the Climax stock are presently unknown. Based on existing knowledge and an extrapolation of available geohydrologic data, it appears that the water table may lie at about 1100 to 1200 m above mean sea level (MSL) in the northeastern part of the stock and at about 800 to 900 m in the southwest. A drilling program would be required to establish these levels precisely. The degree of saturation at a given underground elevation may be approximated by a detailed inventory of seeps at that level. More precise determination of degree of saturation will require a water budet. 27 figures, 2 tables

  19. Formation of chemical gardens on granitic rock. A new type of alteration for alkaline systems

    Satoh, Hisao; Tsukamoto, Katsuo; Garcia-Ruiz, Juan Manuel

    2014-01-01

    In order to understand the groundwater flow at near-underground facilities such as waste repositories, we have studied the effects of flowing an alkaline solution leached from cementitious building materials through the fractures of low-porosity granitic rocks under laboratory conditions. The results show that silica released from the dissolution of sodium-rich plagioclase and quartz reacts with the calcium leached from cementitious buildings to form calcium silicate hydrates (C-S-H) phases in the form of hollow tubular structures. These tubular structures form selectively on the surface of plagioclase in a similar way to reverse silica gardens structures. It was found that the rate of precipitation of C-S-H phases is faster than the rate of dissolution of plagioclase. This selftriggered dissolution/precipitation phenomenon may be an important factor controlling groundwater permeation in natural alkaline underground systems.

  20. Radionuclide diffusion into undisturbed and altered crystalline rocks

    Havlová, V.; Večerník, P.; Najser, J.; Sosna, K.; Breiter, Karel

    2012-01-01

    Roč. 76, Dec. 2012 (2012), s. 3191-3201 ISSN 0026-461X Institutional support: RVO:67985831 Keywords : disposal * granite * radionuclide diffus * ion * sampling protocols Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.212, year: 2012

  1. Evaluation of geologic and geophysical techniques for surface-to-subsurface projections of geologic characteristics in crystalline rock

    1985-07-01

    Granitic and gneissic rock complexes are being considered for their potential to contain and permanently isolate high-level nuclear waste in a deep geologic repository. The use of surface geologic and geophysical techniques has several advantages over drilling and testing methods for geologic site characterization in that the techniques are typically less costly, provide data over a wider area, and do not jeopardize the physical integrity of a potential repository. For this reason, an extensive literature review was conducted to identify appropriate surface geologic and geophysical techniques that can be used to characterize geologic conditions in crystalline rock at proposed repository depths of 460 to 1,220 m. Characterization parameters such as rock quality; fracture orientation, spacing; and aperture; depths to anomalies; degree of saturation; rock body dimensions; and petrology are considered to be of primary importance. Techniques reviewed include remote sensing, geologic mapping, petrographic analysis, structural analysis, gravity and magnetic methods, electrical methods, and seismic methods. Each technique was reviewed with regard to its theoretical basis and field application; geologic parameters that can be evaluated; advantages and limitations, and, where available, case history applications in crystalline rock. Available information indicates that individual techniques provide reliable information on characteristics at the surface, but have limited success in projections to depths greater that approximately 100 m. A combination of integrated techniques combines with data from a limited number of boreholes would significantly improve the reliability and confidence of early characterization studies to provide qualitative rock body characteristics for region-to-area and area-to-site selection evaluations. 458 refs., 32 figs., 14 tabs

  2. Thermal stress microfracturing of crystalline and sedimentary rock. Final report, September 16, 1987--September 15, 1991

    Wang, H.

    1995-08-01

    Slow uniform heating of crustal rocks is both a pervasive geologic process and an anticipated by-product of radioactive waste disposal. Such heating generates microcracks which alter the strength, elastic moduli, and transport properties of the rock. The research program was to understand mechanisms of thermal cracking in rocks. It included development of a theoretical understanding of cracking due to thermal stresses, laboratory work to characterize crack strain in rocks thermally stressed under different conditions (including natural thermal histories), microscopic work to count and catalog crack occurrences, and geologic application to determine paleostress history of granites from the midcontinent

  3. Observations of borehole deformation modulus values before and after extensive heating of a granitic rock mass

    Patrick, W.C.; Yow, J.L.; Caxelrod, M.C.

    1985-01-01

    An extensive campaign of in situ deformation modulus measurements was recently completed using a standard NX borehole jack. These results were obtained in a granite intrusive where spent nuclear-fuel assemblies and electrical heaters had raised the rock temperatures 10 0 C to 40 0 C above ambient. We present an analysis of temperature effects based on 41 preheat and 63 post-heat measurements in three boreholes. Using analysis of covariance statistical techniques, we found that the deformation modulus is affected by heat, loading direction, and position within the borehole. The analysis also uncovered a significant interaction between the effects of heating and loading direction. We used 123 measurements from the same boreholes to evaluate the ''Draft Standard Guide for Estimating the In Situ Modulus of Rock Masses Using the NX-Borehole Jack'' which was recently proposed by Heuze. In particular, we examined the criterion for screening measurements in those cases where contact between the jack platen and the borehole wall was incomplete. We found that the proposed screen appears to operate randomly on the data and is therefore ineffective

  4. U/Th-isotopes as natural analogues for the mobility of actinides in granitic rocks

    Mengel, K.; Gerdes, A.

    2001-01-01

    The short-lived decay products of 238 U ( 234 U and 230 Th) can be used as natural analogues for actinides in a hard rock repository. Their mobility in the past may serve as a key for understanding actinide migration in the future. For generally old calcites of the HRL Aespoethe age of disturbance of 238 U/ 234 U and 234 U/ 230 Th activity ratios ranges from 30 000 to 436 000 years at degrees of disturbance ranging from 0.5 to 6.7. The results obtained imply that during the past 440 000 years U was mobile throughout the tunnel sections of the HRL Aespoeinvestigated here. For the FL Grimsel, the disequilibrium states of the 234 U/ 238 U and 230 Th/ 234 U activity ratios in fracture minerals (calcites silicates) also imply that the reactions causing isotopic disturbances have occurred within the past 500 000 years. The U/Th-isotope data of both the samples from the HRL Aespoeand the FL Grimsel have in common the mobilization of U in secondary fracture minerals by migrating solutions within the past 500 000 years. As for the question of a final disposal of radioactive waste in granite host rocks, the transport of U - and thus of similarly behaving actinides - in migrating underground solutions can therefore not be ruled out, if suitable hydraulic systems are considered. (orig.)

  5. Hydrothermal alterations as natural analogues of radionuclide migration in granitic rocks

    Piantone, P.

    1989-01-01

    The document is the final report of the project Hydrothermal alteration systems as analogues of nuclear waste repositories in granitic rocks which was the subject of contract n 0 F1 1 W/0072-F (CD) performed at shared cost between the Bureau de Recherches Geologiques et Minieres (BRGM), the Commissariat a l'Energie Atomique and the Commission of the European Communities as part of the MIRAGE programme. This study is the continuation of a preliminary study made by BRGM in 1986 and which concerned the same programme. The data given in this report were obtained from the study of the infilling and hydrothermalized walls of a mineralized vein located at Fombillou, Lot Department, in the French Massif Central. A satisfactory model of the processes generated by hydrothermal alteration then by climatic weathering such as formation of new minerals, flow of elements and variations in volume, was thus built. The mobility of elements displaying physical and chemical properties similar to those of radionuclides present in high-level radioactive waste was studied. A preliminary thermodynamic simulation of mineral transformations and transfers of matter during hydrothermal alteration was performed using the calculation code CEQCSY (Chemical EQuilibrium in Complex SYstem). This simulation is based on the values of the main physical and chemical parameters deduced from the analysis of the natural system. On the basis of the results obtained from Fombillou, an appraisal was made of the response of the granitic environment which has been disturbed by a hydrothermal system produced by heat emitted by the storage of high-level radio-active waste as well as its potential capacities of retention in case of possible leakage

  6. Phenomenological study on crystalline rock aiming at evaluation of long-term behaviour of rock mass

    Okubo, Seisuke

    2005-02-01

    This study was started on the basis of the outcomes of the research project conducted between 1994 and 2003. In the fiscal year of 1994 when this project was started, a pneumatic creep testing machine was modified. At the end of the fiscal year of 1994, Inada granite was purchased, and the preliminary tests such as P-wave velocity measurement and Schmidt hammer testing were carried out. Through the fiscal year of 1995, a specimen of Tage tuff under water-saturated condition had been loaded in uniaxial condition in the pneumatic creep testing machine. In the fiscal year of 1995, the uniaxial compression and tension tests, and the short-term creep test of Inada granite were also carried out in the servo-controlled testing machines to obtain the complete stress-strain curves. A hydraulic creep testing machine which was planned to use in the next year was modified for long-term creep testing. Finally, a constitutive equation of variable compliance type was examined based on the experimental results. In the fiscal year of 1996, creep, compression and tension tests were carried out. Two types of pressure maintenance equipment (hydraulic and pneumatic types) were developed and examined. In the fiscal year of 1997, creep, compression and tension tests etc. were again carried out on the basis of the results heretofore. The experimental results of long-term creep testing of Tage tuff, middle-term creep testing of Inada granite were described. In both creep tests, samples were submerged in water. In the fiscal year of 1998, creep testing of Tage tuff was conducted. Results of relatively short-term (middle-term) creep conducted on a servo-controlled testing machine were also described. Sample rock was Sirahama sandstone that showed a considerably large creep strain in low stress level such as 17 % of the uniaxial compression strength. Results of triaxial compression test and uniaxial tension test including unloading-reloading tests were described. In the fiscal years of 1999

  7. A microfluidic approach to water-rock interactions using thin rock sections: Pb and U sorption onto thin shale and granite sections

    Oh, Youn Soo [Institute of Mine Reclamation Technology, Mine Reclamation Corp., 2 Segye-ro, Wonju-si, Gangwon-do, 26464 (Korea, Republic of); Jo, Ho Young, E-mail: hyjo@korea.ac.kr [Department of Earth and Environmental Sciences, Korea University, Anam-dong, Seongbuk-gu, Seoul, 02841 (Korea, Republic of); Ryu, Ji-Hun; Kim, Geon-Young [Korea Atomic Energy Research Institute, 1045 Daedeokdaero, Yuseong-gu, Daejeon, 34057 (Korea, Republic of)

    2017-02-15

    Highlights: • Microfluidic tests was used to investigate water-rock (mineral) interactions. • Pb and U sorption onto thin shale and granite sections was evaluated. • Pb removal by thin shale section is related primarily to Fe-containing minerals. • A slightly larger amount of U was removed onto the thin granite section with Fe-containing minerals. - Abstract: The feasibility of using microfluidic tests to investigate water-rock (mineral) interactions in fractures regarding sorption onto thin rock sections (i.e., shale and granite) of lead (Pb) and uranium (U) was evaluated using a synthetic PbCl{sub 2} solution and uranium-containing natural groundwater as fluids. Effluent composition and element distribution on the thin rock sections before and after microfluidic testing were analyzed. Most Pb removal (9.8 mg/cm{sup 2}) occurred within 3.5 h (140 PVF), which was 74% of the total Pb removal (13.2 mg/cm{sup 2}) at the end of testing (14.5 h, 560 PVF). Element composition on the thin shale sections determined by μ-XRF analysis indicated that Pb removal was related primarily to Fe-containing minerals (e.g., pyrite). Two thin granite sections (biotite rich, Bt-R and biotite poor, Bt-P) exhibited no marked difference in uranium removal capacity, but a slightly higher amount of uranium was removed onto the thin Bt-R section (266 μg/cm{sup 2}) than the thin Bt-P section (240 μg/cm{sup 2}) within 120 h (4800 PVF). However, uranium could not be detected by micro X-ray fluorescence (μ-XRF) analysis, likely due to the detection limit. These results suggest that microfluidic testing on thin rock sections enables quantitative evaluation of rock (mineral)-water interactions at the micro-fracture or pore scale.

  8. Water level fluctuations due to earth tides in a well pumping from slightly fractured crystalline rock

    Marine, I.W.

    1975-01-01

    J At the Savannah River plant of the Atomic Energy Commission near Aiken, South Carolina, there are three distinct groundwater systems: the coastal plain sediments, the crystalline metamorphic rocks, and a buried Triassic basin. The coastal plain sediments include several Cretaceous and Tertiary granular aquifers and aquicludes, the total thickness being about 305 m. Below these sediments, water occurs in small fractures in crystalline metamorphic rock (hornblende schist and gneiss with lesser amounts of quartzite). Water level fluctuations due to earth tides are recorded in the crystalline metamorphic rock system and in the coastal plain sediments. No water level fluctuations due to earth tides have been observed in wells in the Triassic rock because of the very low permeability. The water level fluctuations due to earth tides in the crystalline rock are about 10 cm, and those in the sediments are about 1.8 cm. The use of water level fluctuations due to earth tides to calculate porosity appears to present practical difficulties both in the crystalline metamorphic rock system and in the coastal plain sediments. In a 1-yr pumping test on a well in the crystalline metamorphic rock the flow was controlled to within 0.1 percent of the total discharge, which was 0.94 1/s. The water level fluctuations due to earth tides in the pumping well were 10 cm, the same as when this well was not being pumped. (U.S.)

  9. The geology of the surrounding metamorphic rock of Zaer granite (Morocco): contribution to the search for uranium

    Mathias, Laurent

    1984-01-01

    This research thesis reports a study which aimed at reconstituting the geological history of the Zaer region in Morocco with objectives of mining exploration and of assessment of its uranium metallogenic potential. The author examined the whole geological context by studying stratigraphy, sedimentology, tectonic, and petrography of rocks belonging to the concerned area. The main objective was to determine the origin of uranium between a granitic one and a sedimentary one. This meant a reconstitution of the geological history, and therefore the study of the metamorphized sedimentary surrounding rock, of the intrusive granite and of their different possible relationships. On a first part, the author analysed outcropping formations and tried to assign them with a stratigraphic position. He also tried to define the deposition modalities of these formations which could have conditioned sedimentary sites. In a second part, the author reports the study of geological structures and tectonic in order to try to recognise possible structures which could have promoted uranium deposition and trapping in the surrounding rock as well as in granite. The last part addresses the petrography of the different rocks met in the area, and mineralization, notably that of uranium [fr

  10. Radiometric age determination on some granitic rocks in the Hida Range, central Japan. Remarkable age difference across a fault

    Ito, Hisatoshi; Tanaka, Kazuhiro

    1999-01-01

    K-Ar and zircon fission-track dating was carried out on some granitic rocks in the Hida Range, central Japan. The samples analyzed were collected on both sides of one of the major faults in the Hida Range: the Kurobe-Takase fracture zone. Ages obtained west of the fault are ∼60 Ma, while those obtained to the east of the fault are less than ∼5 Ma. These results indicate a remarkable age difference across the fault. The Okukurobe granite, located west of the fault, cooled rapidly from ∼600degC to ∼240degC between 60-55 Ma, and the Kanazawa granodiorite, located east of the fault, cooled rapidly from ∼600degC to ∼240degC between 5-1 Ma. The Okukurobe granite has remained cooler than ∼240degC since ∼55 Ma. Thus, it was found that the granitic rocks across the fault have experienced a remarkable different cooling history. (author)

  11. Isotopic data bearing on the origin of Mesozoic and Tertiary granitic rocks in the western United States

    DePaolo, D.J.; Farmer, G.L.

    1984-01-01

    A regional survey of initial Nd and Sr isotopic compositions has been done on Mesozoic and Tertiary granitic rocks from a 500 000 km 2 area in California, Nevada, Utah, Arizona, and Colorado. The plutons, which range in composition from quartz diorite to monzogranite, are intruded into accreted oceanic geosynclinal terrains in the west and north and into Precambrian basement in the east. Broad geographic coverage allows the data to be interpreted in the context of the regional pre-Mesozoic crustal structure. Initial Nd isotopic compositions exhibit a huge range, encompassing values typical of oceanic magmatic arcs and Archean basement. The sources of the magmas can be inferred from the systematic geographic variability of Nd isotopic compositions. The plutons in the accreted terrains represent mantle-derived magma that assimilated crust while differentiating at deep levels. Those emplaced into Precambrian basement are mainly derived from the crust. The regional patterns can be understood in terms of: (1) the flux of mantle magma entering the crust; (2) crustal thickness; and (3) crustal age. The mantle magma flux apparently decreased inland; in the main batholith belts purely crustal granitic rocks are not observed because the flux was too large. Inland, crustal granite is common because mantle magma was scarce and the crust was thick, and hot enough to melt. The epsilonsub(Nd) values of peraluminous granite formed by melting of the Precambrian basement depend on the age of the local basement source. (author)

  12. Matrix diffusion in crystalline rocks: coupling of anion exclusion, surface diffusion and surface complexation

    Olin, M.; Valkiainen, M.; Aalto, H.

    1997-12-01

    This report includes both experimental and modelling parts. Also, a novel approach to the diffusion experiments is introduced, where ions of the same electric charge diffuse in opposite directions through the same rock sample. Six rock-types from Olkiluoto radioactive waste disposal investigation site were used in the experiments: granite, weathered granite, mica gneiss, weathered mica gneiss, tonalite and altered mica gneiss/migmatite. The experiments consisted of the determination of the effective diffusion coefficient and the rock capacity factor for tritium, chloride (Cl-36) and sodium (Na-22). The modelling consisted of a chemical model for small pores (< 100 nm), a model for counter ion diffusion and models for the laboratory experiments

  13. Matrix diffusion in crystalline rocks: coupling of anion exclusion, surface diffusion and surface complexation

    Olin, M.; Valkiainen, M.; Aalto, H. [VTT Chemical Technology, Espoo (Finland)

    1997-12-01

    This report includes both experimental and modelling parts. Also, a novel approach to the diffusion experiments is introduced, where ions of the same electric charge diffuse in opposite directions through the same rock sample. Six rock-types from Olkiluoto radioactive waste disposal investigation site were used in the experiments: granite, weathered granite, mica gneiss, weathered mica gneiss, tonalite and altered mica gneiss/migmatite. The experiments consisted of the determination of the effective diffusion coefficient and the rock capacity factor for tritium, chloride (Cl-36) and sodium (Na-22). The modelling consisted of a chemical model for small pores (< 100 nm), a model for counter ion diffusion and models for the laboratory experiments. 21 refs.

  14. Investigated conductive fracture in the granitic rocks by flow-meter logging

    Ogata, Nobuhisa; Koide, Kaoru; Takeichi, Atsushi

    1997-01-01

    Test of the use of a measurement technique for the hydraulic conductivity of geological structures which act as flow paths or are impermeable to groundwater flow. In order to prove the value of flow-meter logging as an in-situ technique for detecting conductive fractures in granitic rocks, the method has been applied to a borehole near the Tono uranium mine, Gifu, Japan. This study in involved with detecting a conductive fracture and calculating the hydraulic conductivities. The results were as follows: (1) In a zone of groundwater inflow into the borehole, the hydraulic conductivity was calculated to be of the order of the 10 -3 - 10 -4 (cm/sec) from flow-meter logging. This value agreed with the results of a in-situ borehole permeability test carried out with a similar depth interval. (2) The study showed that flow-meter logging is effective for detecting the distribution of high conductivity fractures and calculating the hydraulic conductivity. (author)

  15. Evaluation of some chemical analysis of granite rocks for rare elements (Tungsten, Nobuim, Tin, Tantalum)

    Mohmmed, I. A.

    2005-01-01

    In this study, granite rocks samples were collected from Jebel Nikrab, in the eastern Sudan. A total of 16 samples were analyzed for Fe 2 O 3 , Mg O, CaO, Na 2 O, K 2 O and MnO 2 , using the atomic absorption spectrometer (AAS) and SiO 2 Al 2 O 3 using colorimeter. By classical methods analyzed for W, Ta, Nb and Sn, and all these results compared with the results have been done in the international laboratories give the same results even the results of SiO 2 , Al 2 O 3 , Ca O, MnO, Fe 2 O 3 , Mg O, K 2 O and Na 2 O. The range of W (0.0001-0.0005), Sn (0.00010.0024), Ta (0.003-0.0042), Nb (0.007-0.05). The range of oxide of Mn (0.07-0.1), Fe (0.17-17), Mg (0,009-0.3), Ca (0.05-1.2), Na (0.07-4.29) and K (0.02-3.7). (Author)

  16. Tracer movement in a single fissure in granitic rock - some experimental results and their interpretation

    Neretnieks, I.; Eriksen, T.; Taetinen, P.

    1980-08-01

    Radionuclide migration was studied in a natural fissure in a granite core. The fissure was oriented parallel to the axis in a cylindrical core 30 cm long and 20 in diameter. The traced solution was injected at one end of the core and collected at the other. Breakthrough curves were obtained for the nonsorbing tracers tritiated water, and a large molecular weight lignosulphonate molecule and the sorbing tracers cesium and strontium. From the breakthrough curves for the nonsorbing tracers it could be concluded that channeling occurs in the single fissure. A 'dispersion' model based on channeling is presented. The results from the sorbing tracers indicate that there is substantial diffusion into and sorption in the rock matrix. Sorption on the surface of the fissure also accounts for a part of the retardation effect of the sorbing species. A model which includes the mechanisms of channeling, surface sorption matrix diffusion and matrix sorption is presented. The experimental breakthrough curves can be fitted fairly well by this model by use of independently obtained data on diffusivities and matrix sorption. (author)

  17. Tracer Movement in a Single Fissure in Granitic Rock: Some Experimental Results and Their Interpretation

    Neretnieks, Ivars; Eriksen, Tryggve; TäHtinen, PäIvi

    1982-08-01

    Radionuclide migration was studied in a natural fissure in a granite core. The fissure was oriented parallel to the axis in a cylindrical core 30 cm long and 20 cm in diameter. The traced solution was injected at one end of the core and collected at the other. Breakthrough curves were obtained for the nonsorbing tracers, tritiated water, and a large-molecular-weight lignosulphonate molecule and for the sorbing tracers, cesium and strontium. From the breakthrough curves for the nonsorbing tracers it could be concluded that channeling occurs in the single fissure. A `dispersion' model based on channeling is presented. The results from the sorbing tracers indicate that there is substantial diffusion into and sorption in the rock matrix. Sorption on the surface of the fissure also accounts for a part of the retardation effect of the sorbing species. A model which includes the mechanisms of channeling, surface sorption, matrix diffusion, and matrix sorption is presented. The experimental breakthrough curves can be fitted fairly well by this model by use of independently obtained data on diffusivities and matrix sorption.

  18. Paleoproterozoic mojaveprovince in northwestern Mexico? Isotopic and U-Pb zircon geochronologic studies of precambrian and Cambrian crystalline and sedimentary rocks, Caborca, Sonora

    Lang, Farmer G.; Bowring, S.A.; Matzel, J.; Maldonado, G.E.; Fedo, C.; Wooden, J.

    2005-01-01

    Whole-rock Nd isotopic data and U-Pb zircon geochronology from Precambrian crystalline rocks in the Caborca area, northern Sonora, reveal that these rocks are most likely a segment of the Paleoproterozoic Mojave province. Supporting this conclusion are the observations that paragneiss from the ??? 1.75 Ga Bamori Complex has a 2.4 Ga Nd model age and contains detrital zircons ranging in age from Paleo- proterozoic (1.75 Ga) to Archean (3.2 Ga). Paragneisses with similar age and isotopic characteristics occur in the Mojave province in southern California. In addition, "A-type" granite exposed at the southern end of Cerro Rajon has ca 2.0 Ga Nd model age and a U-Pb zircon age of 1.71 Ga, which are similar to those of Paleoproterozoic granites in the Mojave province. Unlike the U.S. Mojave province, the Caborcan crust contains ca. 1.1 Ga granite (Aibo Granite), which our new Nd isotopic data suggest is largely the product of anatexis of the local Precambrian basement. Detrital zircons from Neoproterozoic to early Cambrian miogeoclinal arenites at Caborca show dominant populations ca. 1.7 Ga, ca. 1.4 Ga, and ca. 1.1 Ga, with subordinate Early Cambrian and Archean zircons. These zircons were likely derived predominately from North American crust to the east and northeast, and not from the underlying Caborcan basement. The general age and isotopic similarities between Mojave province basement and overlying miogeoclinal sedimentary rocks in Sonora and southern California is necessary, but not sufficient, proof of the hypothesis that Sonoran crust is allochthonous and was transported to its current position during the Mesozoic along the proposed Mojave-Sonora megashear. One viable alternative model is that the Caborcan Precambrian crust is an isolated, autochthonous segment of Mojave province crust that shares a similar, but not identical, Proterozoic geological history with Mojave province crust found in the southwest United States ?? 2005 Geological Society of America.

  19. Borehole radar applied to the characterization of hydraulically conductive fracture zones in crystalline rock

    Olsson, O.; Falk, L.; Forslund, O.; Lundmark, L.; Sandberg, E.

    1992-01-01

    This paper discusses the borehole radar system, RAMAC, developed within the framework of the International Stripa Project, which can be used in three different measuring modes; single-hole reflection, cross-hole reflection and cross-hole tomography. The reflection modes basically provide geometrical data on features located at some distance from the borehole. In addition the strength of the reflections indicate the contrast in electrical properties. Single-hole reflection data are cylindrically symmetrical with respect to the borehole, which means that a unique fracture orientation cannot be obtained. A method has been devised where absolute orientation of fracture zones is obtained by combining single-hole reflection data from adjacent holes. Similar methods for the analysis of cross-hole reflection data have also been developed and found to be efficient. The radar operates in the frequency range 20-60 MHz which gives a resolution of 1-3 m in crystalline rock. The investigation range obtained in the Stripa granite is approximately 100 m in the single-hole mode and 200-300 m in the cross-hole model. Variations in the arrival time and amplitude of the direct wave between transmitter and receiver have been used for cross-hole tomographic imaging to yield maps of radar velocity and attenuation. The cross-hole measurement configuration coupled with tomographic inversion has less resolution than the reflection methods but provides better quantitative estimates of the values of measured properties. The analysis of the radar data has provided a consistent description of the fracture zones at the Stripa Cross-hole site in agreement with both geological and geophysical observations

  20. Rational Rock Physics for Improved Velocity Prediction and Reservoir Properties Estimation for Granite Wash (Tight Sands in Anadarko Basin, Texas

    Muhammad Z. A. Durrani

    2014-01-01

    Full Text Available Due to the complex nature, deriving elastic properties from seismic data for the prolific Granite Wash reservoir (Pennsylvanian age in the western Anadarko Basin Wheeler County (Texas is quite a challenge. In this paper, we used rock physics tool to describe the diagenesis and accurate estimation of seismic velocities of P and S waves in Granite Wash reservoir. Hertz-Mindlin and Cementation (Dvorkin’s theories are applied to analyze the nature of the reservoir rocks (uncemented and cemented. In the implementation of rock physics diagnostics, three classical rock physics (empirical relations, Kuster-Toksöz, and Berryman models are comparatively analyzed for velocity prediction taking into account the pore shape geometry. An empirical (VP-VS relationship is also generated calibrated with core data for shear wave velocity prediction. Finally, we discussed the advantages of each rock physics model in detail. In addition, cross-plots of unconventional attributes help us in the clear separation of anomalous zone and lithologic properties of sand and shale facies over conventional attributes.

  1. Radiogeochronologic data on rocks of crystalline massifs of Western Carpathians and their interpretation in radiogeochronologic dating

    Cambel, B.

    1979-01-01

    The results are summed up and evaluated of the measurement of the age of various crystalline rocks in the Western Carpathians using the method of isotope dating. The obtained results show that the rocks in the Western Carpathians were formed in the period of the Variscian and Alpine orogenesis, ie., 90 to 550 million years ago. A list of problems is given which must be resolved using radiogeochronological methods for age determination of geological processes and for specifying the stratigraphy of crystalline rocks in the Western Carpathians. (Ha)

  2. Dispersion of uranium in accessory apatite in crystalline rocks and its possible petrogenetic meaning

    Kral, J.; Burchart, J.

    1983-01-01

    The coefficient of variation for grain-by-grain fission track uranium analysis of apatites from igneous rocks seems to reflect the temperature of crystallization and the cooling rate. For metamorphic rocks the coefficient represents a complex record of the homogeneity of the source and of metamorphic neocrystallization. As a test case 41 West Carpathian rocks have been examined and the coefficients of variation for U in apatites found to be: granitic rocks 0.30-0.79, paragneisses 0.35-0.95, migmatites 0.55-0.87, and volcanic rocks 0.30-0.40. Most of the frequency distributions are lognormal, though for some cases a normal distribution gives a better fit, and some are incompatible with either of the two distributions. (orig.)

  3. Preliminary study of the uranium favorability of granitic and contact-metamorphic rocks of the Owens Valley area, Inyo and Mono Counties, California, and Esmeralda and Mineral Counties, Nevada

    Cupp, G.M.; Mitchell, T.P.

    1978-01-01

    Granitic and contact-metamorphic rocks of the Owens Valley area were sampled to determine their favorability for uranium. Uranium deposits associated with these rocks were examined to determine the mode of occurrence. Metamorphic rocks near contacts with intrusive rocks include skarns, schists, quartzites, metaconglomerates, hornfels, gneisses, and metavolcanics. The grade of contact metamorphism ranges from slight to intense, depending upon the distance from the intrusive contact. The average U 3 O 8 content of the metamorphic rock samples is 3 ppM. Metamorphic rock samples in a roof pendant at the Claw prospect contain as much as 3 percent U 3 O 8 . Skarn samples from the Birch Creek pluton contain as much as 114 ppM U 3 O 8 ; those from the Santa Rita Flat pluton contain as much as 23 ppM U 3 O 8 . Most of the intrusive rocks are granite, quartz monzonite, or monzonite. Granodiorite and diorite are less common, and gabbro is rare. The average U 3 O 8 content of the crystalline rock samples is 4 ppM. Samples from a quartz-monzonite pluton east of Lone Pine, California, and quartz monzonite in the Santa Rosa Hills had maximum contents of 28 and 13 ppM U 3 O 8 , respectively. Areas of contact metamorphism and metasomatism, such as those at the Claw prospect and Birch Creek pluton, are probably the most favorable sites for uranium deposits. There are many miles of granitic and contact-metamorphic zones in which undiscovered uranium deposits may exist. Although the overall uranium content of granitic rocks appears to be low, the pluton east of Lone Pine and the Hunter Mountain pluton in the area of the Santa Rosa Hills have sufficient uranium to have acted as uranium and detrital source rocks for uranium deposits that may now be buried in Tertiary sediments in the basins around the plutons. The Claw deposit is the only known uranium deposit of a size and grade to be of possible commercial interest

  4. Application of Ga-Al discrimination plots in identification of high strength granitic host rocks for deep geological repository of high level radioactive waste

    Bajpai, R.K.; Narayan, P.K.; Trivedi, R.K.; Purohit, M.K.

    2010-01-01

    The permanent disposal of vitrified high level wastes and in some cases even spent fuel, is being planned in specifically designed and built deep geological repository located in the depth range of 500-600m in appropriate host rock at carefully selected sites. Such facilities are expected to provide very long term isolation and confinement to the disposed waste by means of long term mechanical stability of such structures that results from very high strength and homogeneity of the chosen rock, geochemical compatible environment around the disposed waste and general lack of groundwater. In Indian geological repository development programme, granites have been selected as target host rock and large scale characterization studies have been undertaken to develop database of mineralogy, petrology, geochemistry and rock mechanical characteristics. The paper proposes a new approach for demarcation of high strength homogeneous granite rocks from within an area of about 100 square kilometres wherein a cocktail of granites of different origins with varying rock mass characteristics co exists. The study area is characterised by the presence of A, S and I type granites toughly intermixed. The S type granites are derived from sedimentary parent material and therefore carry relics of parent fabric and at times undigested material with resultant reduction in their strength and increased inhomogeneity. On the other hand I type varieties are derived from igneous parents and are more homogeneous with sufficient strength. The A type granites are emplaced as molten mass in a complete non-tectonic setting with resultant homogeneous compositions, absence of tectonic fabric and very high strength. Besides they are silica rich with less vulnerability to alterations with time. Thus A type granites are most suited for construction of Deep Geological Repository. For developing a geochemical approach for establishing relation between chemical compositions and rock strength parameters, a

  5. Case histories of roller cone core bit application in crystalline rock

    Dahlem, J.S.

    1988-01-01

    The increased interest in deep crystalline rock drilling projects has resulted in a requirement for premium coring bits which are effective in such a harsh and abrasive environment. Hard formation roller cone insert bits have traditionally and constantly performed well in crystalline rock. As a result, the application of state of the art roller cone rock bit technology to the design and development of core bits has made crystalline coring projects more viable than ever before. This paper follows the development of roller cone core bits by examining their use on project such as HDR (Hot Dry Rock, Los Alamos); NAGRA (Nuclear Waste Disposal Wells in Switzerland); Camborne School of Mines Geothermal Project in Cornwall, UK; Deep Gas Project in Sweden; and the KTB Deep Drilling Project in West Germany

  6. Hydrothermal modification of host rock geochemistry within Mo-Cu porphyry deposits in the Galway Granite, western Ireland

    Tolometti, Gavin; McCarthy, Will

    2016-04-01

    Hydrothermal alteration of host rock is a process inherent to the formation of porphyry deposits and the required geochemical modification of these rocks is regularly used to indicate proximity to an economic target. The study involves examining the changes in major, minor and trace elements to understand how the quartz vein structures have influenced the chemistry within the Murvey Granite that forms part of the 380-425Ma Galway Granite Complex in western Ireland. Molybdenite mineralisation within the Galway Granite Complex occurred in close association with protracted magmatism at 423Ma, 410Ma, 407Ma, 397Ma and 383Ma and this continues to be of interest to active exploration. The aim of the project is to characterize hydrothermal alteration associated with Mo-Cu mineralisation and identify geochemical indicators that can guide future exploration work. The Murvey Granite intrudes metagabbros and gneiss that form part of the Connemara Metamorphic complex. The intrusion is composed of albite-rich pink granite, garnetiferous granite and phenocrytic orthoclase granite. Minor doleritic dykes post-date the Murvey Granite, found commonly along its margins. Field mapping shows that the granite is truncated to the east by a regional NW-SE fault and that several small subparallel structures host Mo-Cu bearing quartz veins. Petrographic observations show heavily sericitized feldspars and plagioclase and biotite which have undergone kaolinization and chloritisation. Chalcopyrite minerals are fine grained, heavily fractured found crystallized along the margins of the feldspars and 2mm pyrite crystals. Molybdenite are also seen along the margins of the feldspars, crystallized whilst the Murvey Granite cooled. Field and petrographic observations indicate that mineralisation is structurally controlled by NW-SE faults from the selected mineralization zones and conjugate NE-SW cross cutting the Murvey Granite. Both fault orientations exhibit quartz and disseminated molybdenite

  7. Relict zircon U-Pb age and O isotope evidence for reworking of Neoproterozoic crustal rocks in the origin of Triassic S-type granites in South China

    Gao, Peng; Zheng, Yong-Fei; Chen, Yi-Xiang; Zhao, Zi-Fu; Xia, Xiao-Ping

    2018-02-01

    Granites derived from partial melting of sedimentary rocks are generally characterized by high δ18O values and abundant relict zircons. Such relict zircons are valuable in tracing the source rocks of granites and the history of crustal anatexis. Here we report in-situ U-Pb ages, O isotopes and trace elements in zircons from Triassic granites in the Zhuguangshan and Jiuzhou regions, which are located in the Nanling Range and the Darongshan area, respectively, in South China. Zircon U-Pb dating yields magma crystallization ages of 236 ± 2 Ma for the Zhuguangshan granites and 246 ± 2 Ma to 252 ± 3 Ma for the Jiuzhou granites. The Triassic syn-magmatic zircons are characterized by high δ18O values of 10.1-11.9‰ in Zhuguangshan and 8.5-13.5‰ in Jiuzhou. The relict zircons show a wide range of U-Pb ages from 315 to 2185 Ma in Zhuguangshan and from 304 to 3121 Ma in Jiuzhou. Nevertheless, a dominant age peak of 700-1000 Ma is prominent in both occurrences, demonstrating that their source rocks were dominated by detrital sediments weathered from Neoproterozoic magmatic rocks. Taking previous results for regional granites together, Neoproterozoic relict zircons show δ18O values in a small range from 5 to 8‰ for the Nanling granites but a large range from 5 to 11‰ for the Darongshan granites. In addition, relict zircons of Paleozoic U-Pb age occur in the two granitic plutons. They exhibit consistently high δ18O values similar to the Triassic syn-magmatic zircons in the host granites. These Paleozoic relict zircons are interpreted as the peritectic product during transient melting of the metasedimentary rocks in response to the intracontinental orogenesis in South China. Therefore, the relict zircons of Neoproterozoic age are directly inherited from the source rocks of S-type granites, and those of Paleozoic age record the transient melting of metasedimentary rocks before intensive melting for granitic magmatism in the Triassic.

  8. Modelling the diffusion-available pore space of an unaltered granitic rock matrix using a micro-DFN approach

    Svensson, Urban; Löfgren, Martin; Trinchero, Paolo; Selroos, Jan-Olof

    2018-04-01

    In sparsely fractured rock, the ubiquitous heterogeneity of the matrix, which has been observed in different laboratory and in situ experiments, has been shown to have a significant influence on retardation mechanisms that are of importance for the safety of deep geological repositories for nuclear waste. Here, we propose a conceptualisation of a typical heterogeneous granitic rock matrix based on micro-Discrete Fracture Networks (micro-DFN). Different sets of fractures are used to represent grain-boundary pores as well as micro fractures that transect different mineral grains. The micro-DFN model offers a great flexibility in the way inter- and intra-granular space is represented as the different parameters that characterise each fracture set can be fine tuned to represent samples of different characteristics. Here, the parameters of the model have been calibrated against experimental observations from granitic rock samples taken at Forsmark (Sweden) and different variant cases have been used to illustrate how the model can be tied to rock samples with different attributes. Numerical through-diffusion simulations have been carried out to infer the bulk properties of the model as well as to compare the computed mass flux with the experimental data from an analogous laboratory experiment. The general good agreement between the model results and the experimental observations shows that the model presented here is a reliable tool for the understanding of retardation mechanisms occurring at the mm-scale in the matrix.

  9. Natural analogue for storage of radwaste in crystalline rocks

    Brookins, D.G.; Abashian, M.S.; Cohen, L.H.; Wollenberg, H.A. Jr.

    1982-01-01

    The Bryan-Eldora stock (Colorado) intruded the Precambrian Idaho Springs Formation metamorphic rocks 58 million years ago. Geochronologic-geochemical work by Hart et al. [S.R. Hart et al., in Radiometric Dating for Geologists, E.I. Hamilton, R.S. Farquhar, eds. (Wiley-Interscience, New York, 1968) pp. 73-110] has demonstrated that the heat from the cooling intrusive rocks was sufficient to affect mineral isotopic systematics up to 2000 m from the contact, and the nature of these isotopic perturbations can be explained by a simple diffusion model in turn based on various heat flow models. Our new studies are focused on elemental exchange between stock and intruded rock as a function of distance from the contact; the assumption is made that the stock is a very large, high heat source analogous to a waste form emplaced in the metamorphic rocks without benefit of canister or engineered backfill. Data for U, Th and the REE indicate actinide and lanthanide immobility except perhaps in the 0 to 2m contact zone where some infiltration of the country rocks by stock-derived fluids occurred. Beyond 4m no stock-derived U, Th, REE or *Pb are noted. Further, whole rock Rb-Sr and stable O isotopic data indicate conductive cooling as opposed to convective, water-induced cooling. The intruded rocks possess low porosity and permeability; this helped prevent elemental migration during the 10 5 to 10 6 years of stock crystallization. The petrographic and geochemical studies show that the Idaho Springs (or equivalent) metamorphic rocks are well suited for radwaste storage. 1 figure, 1 table

  10. Nuclear waste. DOE has terminated research evaluating crystalline rock for a repository

    Fultz, Keith O.; Sprague, John W.; Weigel, Dwayne E.; Price, Vincent P.

    1989-05-01

    We found that DOE terminated funding of research projects specifically designed to evaluate the suitability of crystalline rock for a repository. DOE continued other research efforts involving crystalline rock because they will provide information that it considers useful for evaluating the suitability of Yucca Mountain, Nevada, for a potential repository. Such research activities are not prohibited by the amendments. In January 1988, DOE began evaluating both its domestic and international research programs to ensure their compliance with the 1987 amendments. Several DOE offices and contractors were involved in the evaluation. DOE officials believe that the evaluation effectively brought the Office of Civilian Radioactive Waste Management activities into compliance with the amendments while maintaining useful international relations of continuing benefit to the nuclear waste program in general and to DOE's investigation of the Yucca Mountain site in particular. (The 1987 amendments designated Yucca Mountain as the only site that DOE is to investigate for a potential repository.) The approach and results of DOE's evaluation are discussed. Our review of DOE documents indicates that, by June 22, 1988, DOE completed its evaluation of ongoing crystalline rock research projects to ensure compliance with the 1987 amendments, terminated those research activities it identified as being specifically designed to evaluate the suitability of crystalline rock for a repository, continued some research activities involving crystalline rock because these activities would benefit the investigation and development of the Yucca Mountain repository site, and redirected some research activities so that they would contribute to investigating and developing the Yucca Mountain site

  11. Nd:YVO{sub 4} laser removal of graffiti from granite. Influence of paint and rock properties on cleaning efficacy

    Rivas, T., E-mail: trivas@uvigo.es [Dpto. Ingenieria de los Recursos Naturales y Medio Ambiente. Universidad de Vigo, Lagoas-Marcosende s/n, 36310 Vigo (Spain); Pozo, S. [Dpto. Ingenieria de los Recursos Naturales y Medio Ambiente. Universidad de Vigo, Lagoas-Marcosende s/n, 36310 Vigo (Spain); Fiorucci, M.P.; Lopez, A.J.; Ramil, A. [Centro de Investigacions Tecnoloxicas (CIT), Universidade da Coruna, 15403 Ferrol (Spain)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Cleaning using NdYVO{sub 4} laser at 355 nm of four different graffiti colours applied on granites. Black-Right-Pointing-Pointer Analysis of the influence of paint composition and properties of rocks on the process. Black-Right-Pointing-Pointer Composition of the paints and, in turn reflectance, determine the removal effectiveness. Black-Right-Pointing-Pointer The laser removal is not conditioned by properties of the stones. - Abstract: This paper presents the cleaning efficiency results for four differently coloured graffiti paints applied to two types of granitic stone by Nd:YVO{sub 4} laser at 355 nm. The paints were characterized in terms of mineralogy and chemistry using x-ray fluorescence, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM); paint absorbance in the ultraviolet-visible-infrared range (200-2000 nm) was also assessed. The studied granites had different mineralogy, texture and porosity properties. Cleaning efficiency was evaluated by polarized microscopy, SEM, FTIR spectroscopy and spectrophotometer colour measurements. The results indicate differences in the effectiveness of surface cleaning for the blue, red and black paints as opposed to the silver paint, mainly attributed to chemical composition. No evidence was found that the granite properties had a bearing on laser effectiveness, although the degree, type and spatial distribution of transgranular fissures in the stone affected the overall assessment of cleaning effectiveness. Polarized light microscopy observations and colour measurements showed that the intensity and distribution of fissures affect the depth of paint penetration, ultimately affecting the cleaning efficiency for both granites.

  12. Nd:YVO4 laser removal of graffiti from granite. Influence of paint and rock properties on cleaning efficacy

    Rivas, T.; Pozo, S.; Fiorucci, M.P.; López, A.J.; Ramil, A.

    2012-01-01

    Highlights: ► Cleaning using NdYVO 4 laser at 355 nm of four different graffiti colours applied on granites. ► Analysis of the influence of paint composition and properties of rocks on the process. ► Composition of the paints and, in turn reflectance, determine the removal effectiveness. ► The laser removal is not conditioned by properties of the stones. - Abstract: This paper presents the cleaning efficiency results for four differently coloured graffiti paints applied to two types of granitic stone by Nd:YVO 4 laser at 355 nm. The paints were characterized in terms of mineralogy and chemistry using x-ray fluorescence, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM); paint absorbance in the ultraviolet–visible-infrared range (200–2000 nm) was also assessed. The studied granites had different mineralogy, texture and porosity properties. Cleaning efficiency was evaluated by polarized microscopy, SEM, FTIR spectroscopy and spectrophotometer colour measurements. The results indicate differences in the effectiveness of surface cleaning for the blue, red and black paints as opposed to the silver paint, mainly attributed to chemical composition. No evidence was found that the granite properties had a bearing on laser effectiveness, although the degree, type and spatial distribution of transgranular fissures in the stone affected the overall assessment of cleaning effectiveness. Polarized light microscopy observations and colour measurements showed that the intensity and distribution of fissures affect the depth of paint penetration, ultimately affecting the cleaning efficiency for both granites.

  13. Petrography, mineral chemistry and lithochemistry of the albitite and granite-gneissics rocks of anomaly 35 from Lagoa Real uranium province

    Santos, Camila Marques dos

    2016-01-01

    In the northwestern portion of the Lagoa Real Uranium Province (LRUP), located in south-central Bahia, it is located one of the most promising uranium anomalies Brazil (an35, Gameleira I deposit), the reserves and proximity to the Cachoeira mine. Other anomalies of this sector (eg. 31 AN and AN34), are also considered strategic for the content of radioactive minerals and REE. The objective was to develop a study of a representative drill core of an35, where the main rocks PULR are present. The research focused on the mineralogical and chemical changes observed in the passages of a lithology to another, from the rock to the meta granitic albitites, through gneiss and transitional rocks, and making comparisons with similar lithologies sampled on testimonies of AN31 and 34. The granites are classified as hypersolvus coarse alkali-feldspar granite and are variably deformed. The main mineral assemblage in granites are perthitic orthoclase+hedenbergite+ quartz +hastingsite + biotite, and zircon, apatite, ilmenite and titanite are accessories. The reddening of these rocks are characterized by feldspars sericitization and hematitization and the presence of 'vazios'. The gneisses are mainly gray and reach milonitic to protomilonitics terms. These rocks have characteristics of subsolidus changes as swapped rims and metasomatic perthites. The tardi-magmatic association (amphibole+biotite) indicates final crystallization or late influx by superficial fluids resulting in an increase in water and volatiles, such as F and Cl in the system, which must also have carried rare-earth elementsGranites have geochemical affinity with A-type ferroan granite, A2, reduced and are post-collisional. Their patterns of incompatible elements and rare earths are comparable to Sao Timoteo Granite, but their petrographic features indicate that it is a less common granite facies. Albitites were classified as garnet albitites, magnetite albitites and biotite albitites. Contacts between

  14. The Influence Of Hydrothermal Alteration And Weathering On Rock Magnetic Properties Of Granites From The Eps-1 Drilling (soultz-sous-forÊts / France)

    Just, J.; Schleicher, A.; Kontny, A.; de Wall, H.

    The EPS-1 drilling in Soultz-sous-Forêts (Rhinegraben, France) recovered a core pro- file of Tertiary to Permo-Mesozoic sediments deposited on a Variscan granitic base- ment. Magnetic susceptibility (k) measurements on the core material revealed a con- tinous increase from the basement/cover boundary (kmean 0.4 x 10-3 SI) into the magnetite-bearing granite (kmean 13 x 10-3 SI) over a depth range of 1417 U 1555 m. Rock magnetic and mineralogic studies were performed for the fresh granite, the hydrothermally altered granite near a fault zone and the altered granite from the fossil land surface near the basement/cover boundary. The decrease in susceptibility can be correlated with a gradual decomposition of magnetite to hematite and an alteration of the matrix minerals feldspars, biotite and hornblende to clay minerals and carbon- ates. Along with this transition, characteristic rock magnetic signatures can be dis- criminated for different degrees of alteration. While temperature-dependent magnetic susceptibility k(T)-curves in fresh granites indicate a typical multidomain magnetite course with good reversibility, different types of irreversible courses are observed for the altered granite. However, hematite could not be identified in the k(T)-curves. Al- tered granite shows relatively weak magnetic behaviour in AF-demagnetisation exper- iments, untypical for hematite. The alteration of the fresh granite also causes a change in magnetic fabric parameter, especially of the anisotropy factor. The magnetic min- eralogy from the altered granite in respect to the changes in rock magnetic properties will be discussed.

  15. Determination of near field excavation disturbance in crystalline rock

    Koopmans, R.; Hughes, R.W.

    1986-01-01

    The computerized dilatometer system has rapidly and economically provided deformation moduli of low and high modulus rock, determined the extent of excavation disturbance surrounding an underground opening and located open fracture within a rock mass. Results from both test sites indicate that the moduli obtained were influenced by the in situ tangential stress field. It has been shown that the near field excavation disturbance is kept to a minimum through the use of careful excavation techniques such as the tunnel boring machine. In turn, the in situ tangential stress levels and deformation moduli are maximized while the corresponding permeability is minimized

  16. Study on effects of coupled phenomenon on long-term behavior for crystalline rock (Joint research)

    Kimoto, Kazushi; Ichikawa, Yasuaki; Matsui, Hiroya

    2017-11-01

    It is important to evaluate the stability of a repository for high-level radioactive waste not only during the design, construction and operation phases, but also during the post-closure period, for time frames likely exceeding several millennia or longer. The rock mass around the tunnels could be deformed through time in response to time dependent behavior such as creep and stress relaxation. On the other hand, it was revealed that chemical reaction of groundwater in rock has an influence on the long-term behavior. Therefore, an evaluation of the microcracks influencing on rock mechanical and chemical coupled phenomena is the issue to understand the past long-term behavior of rock mass. In view of above points, this study has been started as joint research with Okayama University from Fiscal Year 2016. In Fiscal Year 2016, several kinds of elastic wave velocity were measured using ultra sonic sensors and laser Doppler vibrometer to evaluate the anisotropy of different elastic wave in granite. The velocity measurements were carried out focused on transmitted wave and surface wave. The results showed that strong anisotropy was observed in transmitted P-wave velocity while weak anisotropy was observed in transmitted S-wave and group velocity estimated by surface velocity measurement. In addition, data obtained from surface velocity measurement was partitioned into transmitted and reflected waves and analyzed them in detail. It resulted that elastic wave due to mineral particles to compose granite was dispersed; however, significant dispersion was only observed at specific location. For the future study, understanding of the relationship between density and anisotropy of micro cracks also anisotropy and strong dispersion of group velocity is important subject to estimate the geometrical distribution of micro cracks in granitic rock. (author)

  17. Tourmaline occurrences within the Penamacor-Monsanto granitic pluton and host-rocks (Central Portugal): genetic implications of crystal-chemical and isotopic features

    da Costa, I. Ribeiro; Mourão, C.; Récio, C.; Guimarães, F.; Antunes, I. M.; Ramos, J. Farinha; Barriga, F. J. A. S.; Palmer, M. R.; Milton, J. A.

    2014-04-01

    Tourmalinization associated with peraluminous granitic intrusions in metapelitic host-rocks has been widely recorded in the Iberian Peninsula, given the importance of tourmaline as a tracer of granite magma evolution and potential indicator of Sn-W mineralizations. In the Penamacor-Monsanto granite pluton (Central Eastern Portugal, Central Iberian Zone), tourmaline occurs: (1) as accessory phase in two-mica granitic rocks, muscovite-granites and aplites, (2) in quartz (±mica)-tourmaline rocks (tourmalinites) in several exocontact locations, and (3) as a rare detrital phase in contact zone hornfels and metapelitic host-rocks. Electron microprobe and stable isotope (δ18O, δD, δ11B) data provide clear distinctions between tourmaline populations from these different settings: (a) schorl-oxyschorl tourmalines from granitic rocks have variable foititic component (X□ = 17-57 %) and Mg/(Mg + Fe) ratios (0.19-0.50 in two-mica granitic rocks, and 0.05-0.19 in the more differentiated muscovite-granite and aplites); granitic tourmalines have constant δ18O values (12.1 ± 0.1 ‰), with wider-ranging δD (-78.2 ± 4.7 ‰) and δ11B (-10.7 to -9.0 ‰) values; (b) vein/breccia oxyschorl [Mg/(Mg + Fe) = 0.31-0.44] results from late, B- and Fe-enriched magma-derived fluids and is characterized by δ18O = 12.4 ‰, δD = -29.5 ‰, and δ11B = -9.3 ‰, while replacement tourmalines have more dravitic compositions [Mg/(Mg + Fe) = 0.26-0.64], close to that of detrital tourmaline in the surrounding metapelitic rocks, and yield relatively constant δ18O values (13.1-13.3 ‰), though wider-ranging δD (-58.5 to -36.5 ‰) and δ11B (-10.2 to -8.8 ‰) values; and (c) detrital tourmaline in contact rocks and regional host metasediments is mainly dravite [Mg/(Mg + Fe) = 0.35-0.78] and oxydravite [Mg/(Mg + Fe) = 0.51-0.58], respectively. Boron contents of the granitic rocks are low (<650 ppm) compared to the minimum B contents normally required for tourmaline saturation in

  18. Mechanical behavior of host rock close to H.L.W. disposal cavities in a deep granitic formation

    Hoorelbeke, J.M.; Dourthe, M.

    1986-01-01

    The construction of a H.L.W. repository in a deep granitic formation creates mechanical disturbances in the rock on the scale of the massif and in the nearfield. Amongst all the disturbances noted in the nearfield, this study is concerned with examining the evolution of stresses linked with the excavation of the rock and the rise in temperature in the proximity of the waste packages. Several linear elasticity calculations were made using on the one hand finite element models and on the other simple analytical models. These calculations concern two different storage concepts - in room concept and in floor concept- whose differences in mechanical behavior are analyzed. A study of sensitivity with regard to the characteristics of the rock and to the initial geostatic stresses is presented. The comparison of the calculated stresses with three-dimensional failure criteria gives a clear indication of the satisfactory behavior of granite for final storage. However, the need for experimental study and complementary calculation must be emphasized

  19. Microstructural variation of vitrified floor tile incorporated with granitic rock waste; Variacao microestrutural de piso ceramico vitrificado incorporado com residuos de rocha granitica

    Souza, A.J.; Holanda, J.N.F., E-mail: ajsouza@uenf.b [Universidade Estadual do Norte Fluminense Darcy Ribeiro (LAMAV/CCT/UENF), Campos dos Goytacazes, RJ (Brazil). Lab. de Materiais Avancados. Grupo de Materiais Ceramicos

    2009-07-01

    The ornamental rock industry from Northwest Fluminense generates huge amounts of wastes in the form of a fine powder. These wastes are deposited in nature without any care about environmental degradation, which can cause damage to public health, pollution of the natural water sources, and silted banks of rivers. In addition, they also can to affect the landscape aesthetically. In this work was used a granitic rock waste from Santo Antonio de Padua-RJ. This waste is rich in alkaline oxides, which promote the formation of liquid phase and assist the densification of traditional ceramics. The ceramic bodies with up to 47.5% granitic rock waste were pressed at 50 MPa. The ceramic pieces were fired at 1250 deg C. The evolution of sintered microstructure was evaluated by scanning electron microscopy and X-ray diffraction. The results showed that the granitic rock waste influences significantly the microstructure of the sintered ceramic bodies. (author)

  20. Groundwater Flow and Radionuclide Transport in Fault Zones in Granitic Rock

    Geier, Joel Edward

    2004-12-01

    Fault zones are potential paths for release of radioactive nuclides from radioactive-waste repositories in granitic rock. This research considers detailed maps of en echelon fault zones at two sites in southern Sweden, as a basis for analyses of how their internal geometry can influence groundwater flow and transport of radioactive nuclides. Fracture intensity within these zones is anisotropic and correlated over scales of several meters along strike, corresponding to the length and spacing of the en echelon steps. Flow modeling indicates these properties lead to correlation of zone transmissivity over similar scales. Intensity of fractures in the damage zone adjoining en echelon segments decreases exponentially with distance. These fractures are linked to en echelon segments as a hierarchical pattern of branches. Echelon steps also show a hierarchical internal structure. These traits suggest a fractal increase in the amount of pore volume that solute can access by diffusive mass transfer, with increasing distance from en echelon segments. Consequences may include tailing of solute breakthrough curves, similar to that observed in underground tracer experiments at one of the mapping sites. The implications of echelon-zone architecture are evaluated by numerical simulation of flow and solute transport in 2-D network models, including deterministic models based directly on mapping data, and a statistical model. The simulations account for advection, diffusion-controlled mixing across streamlines within fractures and at intersections, and diffusion into both stagnant branch fractures and macroscopically unfractured matrix. The simulations show that secondary fractures contribute to retardation of solute, although their net effect is sensitive to assumptions regarding heterogeneity of transmissivity and transport aperture. Detailed results provide insight into the function of secondary fractures as an immobile domain affecting mass transfer on time scales relevant to

  1. Technology needs for selecting and evaluating high-level waste repository sites in crystalline rock

    1988-12-01

    This report describes properties and processes that govern the performance of the geological barrier in a nuclear waste isolation system in crystalline rock and the state-of-the-art in the understanding of these properties and processes. Areas and topics that require further research and development as well as technology needs for investigating and selecting repository sites are presented. Experiences from the Swedish site selection program are discussed, and a general investigation strategy is presented for an area characterization phase of an exploratory program in crystalline rocks. 255 refs., 65 figs., 10 tabs

  2. Chemical and Physical Characteristics of Pulverized Granitic Rock Adjacent to the San Andreas, Garlock and San Jacinto Faults: Implications for Earthquake Physics

    Rockwell, T. K.; Sisk, M.; Stillings, M.; Girty, G.; Dor, O.; Wechsler, N.; Ben-Zion, Y.

    2008-12-01

    We present new detailed analyses of pulverized granitic rocks from sections adjacent to the San Andreas, Garlock and San Jacinto faults in southern California. Along the San Andreas and Garlock faults, the Tejon Lookout Granite is pulverized in all exposures within about 100 m of both faults. Along the Clark strand of the San Jacinto fault in Horse Canyon, the pulverization of granitic rocks is highly asymmetric, with a much broader zone of pulverization along the southwest side of the Clark fault. In areas where the granite is injected as dyke rock into schist, only the granitic rock shows pulverization, demonstrating the control of rock type on the pulverization process. Chemical analyses indicate little or no weathering in the bulk of the rock, although XRD analysis shows the presence of smectite, illite, and minor kaolinite in the clay-sized fraction. Weathering products may dominate in the less than 1 micron fraction. The average grain size in all samples of pulverized granitic rock range between about 20 and 200 microns (silt to fine sand), with the size distribution in part a function of proximity to the primary slip zone. The San Andreas fault samples are generally finer than those collected from along the Garlock or San Jacinto faults. The particle size distribution for all samples is non-fractal, with a distinct slope break in the 60-100 micron range, which suggests that pulverization is not a consequence of direct shear. This average particle size is quite coarser than previous reports, which we attribute to possible measurement errors in the prior work. Our data and observations suggest that dynamic fracturing in the wall rock of these three major faults only accounts for 1% or less of the earthquake energy budget.

  3. Study on crystalline rock for evaluating method of long-term behavior. FY2012 (Contract research)

    Fukui, Katsunori; Hashiba, Kimihiro; Tanno, Takeo; Hikima, Ryoichi; Sanada, Hiroyuki; Sato, Toshinori

    2013-12-01

    Rock shows time-dependent behavior such as creep/relaxation. With respect to high-level radioactive waste disposal, knowledge of the long-term mechanical stability of shafts and galleries excavated in rock are required, over a period of thousands of years after closure as well as during construction and operation. Therefore, it is very important to understand the time-dependent behavior of rock for evaluating long-term mechanical stability. The purpose of this study is to determine the mechanisms of time-dependent behavior of rock by the precise test (e.g. laboratory creep test), observation and measurement and to develop methods for evaluating long-term mechanical stability. In previous works, testing techniques were established and basic evaluation methods were developed. Recently, some parameters, which required for simulation of time-dependent behavior, were determined for the modeling of biotite granite (Toki granite) distributed around the Mizunami underground research laboratory. However, we were not able to obtain enough data to assess the reliability of the method to evaluate these parameters. This report describes the results of the research activities carried out in fiscal year 2012. In Chapter 1, we provide background and an overview of this study. In Chapter 2, the results of a long-term creep test on Tage tuff, started in fiscal year 1997, are described. In Chapter 3, the experimental results concerning the loading-rate dependency of rock strength were examined to understand the time-dependent behavior of rock. In Chapter 4, the stability of tunnels, under conditions which rock stress is larger than that around a circular tunnel, were examined to obtain useful information on the future plan for in-situ tests in the underground research laboratory. (author)

  4. Physical Matrix Characterisation: Studies of Crystalline Rocks and Consolidated Clays by PMMA Method and Electron Microscopy as Support of Diffusion Analyses

    Siitari-Kauppi, M.; Leskinen, A.; Kelokaski, A.; Togneri, L.; Alonso, U.; Missana, T.; Garcia-Gutierrez, M.; Patelli, A.

    2007-07-01

    Crystalline rock and consolidated clay are both considered adequate host rocks for a high-level radioactive waste deep geological repository (HLWR). Over the extended periods of HLWR operation, long-lived radionuclides (RN) may be released from the fuel and migrate to the geo/biosphere. To predict the fate of contaminants and to assess the safety of the host rock, it is very important to determine transport parameters, as diffusion coefficients, and to relate them to the physical properties of the barriers, as connected porosity. In heterogeneous materials, it is also a major task to describe the transport at the mineral scale evaluating diffusion coefficients and mineral-specific porosities on single minerals. The main objective of this study was to determine within granite and consolidated clay, the connective porosity and mineral-specific porosities by poly-methylmethacrylate (PMMA) autoradiography method. Scanning electron microscopy and energy-dispersive X-ray analyses (FESEM/EDS) were performed in order to study the pore apertures of porous regions in greater detail and to identify the corresponding minerals. By the novel application of the nuclear ion beam technique Rutherford Backscattering Spectrometry (RBS) apparent diffusion coefficients were determined at mineral scale. Finally, the porosity results were used to evaluate the effective diffusion coefficients and retention parameters of single minerals in different granite samples and consolidated clays. (Author) 42 refs.

  5. Physical Matrix Characterisation: Studies of Crystalline Rocks and Consolidated Clays by PMMA Method and Electron Microscopy as a Support of Diffusion Analyses

    Siitari-Kauppi, M.; Leskinen, A.; Kelokaski, A.; Togneri, L.; Alonso, U.; Missana, T.; Garcia-Gutierrez, M.; Patelli, A.

    2007-01-01

    Crystalline rock and consolidated clay are both considered adequate host rocks for a high-level radioactive waste deep geological repository (HLWR). Over the extended periods of HLWR operation, long-lived radionuclides (RN) may be released from the fuel and migrate to the geo/biosphere. To predict the fate of contaminants and to assess the safety of the host rock, it is very important to determine transport parameters, as diffusion coefficients, and to relate them to the physical properties of the barriers, as connected porosity. In heterogeneous materials, it is also a major task to describe the transport at the mineral scale evaluating diffusion coefficients and mineral-specific porosities on single minerals. The main objective of this study was to determine within granite and consolidated clay, the connective porosity and mineral-specific porosities by poly-methylmethacrylate (PMMA) autoradiography method. Scanning electron microscopy and energy-dispersive X-ray analyses (FESEM/EDS) were performed in order to study the pore apertures of porous regions in greater detail and to identify the corresponding minerals. By the novel application of the nuclear ion beam technique Rutherford Backscattering Spectrometry (RBS) apparent diffusion coefficients were determined at mineral scale. Finally, the porosity results were used to evaluate the effective diffusion coefficients and retention parameters of single minerals in different granite samples and consolidated clays. (Author) 42 refs

  6. Release of U, Th, and REE from granitic rock: A mineralogical approach

    Markovaara-Koivisto, M.

    2006-01-01

    Finland plans to dispose of its spent nuclear fuel deep in the bedrock, and comprehensive assessment of the potential risks is required. One risk is glaciations induced by climate change, which might eventually cause malfunction of the engineered barrier system and breakdown of the copper-iron canisters containing the spent fuel. The fuel might then come into contact with groundwater. This groundwater might be acidic rain water, or oxygenated glacial melt water, which intrudes into the bedrock with hydrostatic pressure under the ice sheet. In this study, behaviour of uranium and rare earth elements was investigated in the Palmottu uranium deposit. Studies in the Palmottu deposit provide an indication of how uranium and other harmful elements could migrate from the repository to the surrounding bedrock in the event the canisters were breached. The spent fuel contains uranium and other actinides. The possible release of these elements and their behaviour after release in bedrock and groundwater were studied by means of chemical analogues occurring in nature, namely uranium (U), thorium (Th) and rare earth elements (REE). The study was focused on the mode of occurrence of these elements in granitic rocks. The chemistry of the mineral phases was explored by scanning electron microscopy and wavelength dispersive spectrometry, while the release of the elements was investigated with leaching experiments. In the first phase the samples were leached with artificial groundwater. In the second phase a HNO 3 solution of pH 5 was used, and in the final step a solution of pH 3. The U, Th and REE phases after each leaching were studied by fieldemission scanning electron microscopy and energy dispersive XRay microanalysis (EDAX), and the leachates were analysed by mass spectrometry (ICPMS and ICPAES). The aim of this study was to clarify how U, Th and REEs behave in the leaching processes associated with solutions simulating possible natural water conditions in the bedrock and to

  7. Observations from borehole dilution logging experiments in fractured crystalline rock under variable hydraulic conditions

    Harte, Philip T.; Anderson, Alton; Williams, John H.

    2014-01-01

    Identifying hydraulically active fractures in low permeability, crystalline-bedrock aquifers requires a variety of geophysical and hydrogeophysical borehole tools and approaches. One such approach is Single Borehole Dilution Tests (SBDT), which in some low flow cases have been shown to provide greater resolution of borehole flow than other logging procedures, such as vertical differential Heat Pulse Flowmeter (HPFM) logging. Because the tools used in SBDT collect continuous profiles of water quality or dye changes, they can identify horizontal flow zones and vertical flow. We used SBDT with a food grade blue dye as a tracer and dual photometer-nephelometer measurements to identify low flow zones.SBDT were conducted at seven wells with open boreholes (exceeding 300 ft). At most of the wells HPFM logs were also collected. The seven wells are set in low-permeability, fractured granite and gneiss rocks underlying a former tetrachloroeythylene (PCE) source area at the Savage Municipal Well Superfund site in Milford, NH. Time series SBDT logs were collected at each of the seven wells under three distinct hydraulic conditions: (1) ambient conditions prior to a pump test at an adjacent well, (2) mid test, after 2-3 days of the start of the pump test, and (3) at the end of the test, after 8-9 days of the pump test. None of the SBDT were conducted under pumping conditions in the logged well. For each condition, wells were initially passively spiked with blue dye once and subsequent time series measurements were made.Measurement accuracy and precision of the photometer tool is important in SBDT when attempting to detect low rates of borehole flow. Tests indicate that under ambient conditions, none of the wells had detectable flow as measured with HPFM logging. With SBDT, 4 of the 7 showed the presence of some very low flow. None of 5 (2 of the 7 wells initially logged with HPFM under ambient conditions were not re-logged) wells logged with the HPFM during the pump test had

  8. Extra-terrestrial igneous granites and related rocks: A review of their occurrence and petrogenesis

    Bonin, Bernard

    2012-11-01

    The telluric planets and the asteroid belt display the same internal structure with a metallic inner core and a silicate outer shell. Experimental data and petrological evidence in silicate systems show that granite can be produced by extreme igneous differentiation through various types of igneous processes. On Moon, 4.4-3.9 Ga granite clasts display dry mineral assemblages. They correspond to at least 8 discrete intrusive events. Large K/Ca enrichment and low REE abundances in granite relative to KREEP are consistent with silicate liquid immiscibility, a process observed in melt inclusions within olivine of lunar basalts and in lunar meteorites. Steep-sided domes identified by remote sensing can represent intrusive or extrusive felsic formations. On Mars, black-and-white rhythmic layers observed on the Tharsis rise along the flanks of the peripheral scarps of the Tharsis Montes giant volcanoes suggest the possible eruption of felsic pyroclastites. Though no true granites were found so far in the Martian SNC meteorites, felsic glasses and mesostases were identified and a component close to terrestrial continental (granitic) crust is inferred from trace element and isotope systematics. Venus has suffered extensive volcanic resurfacing, whereas folded and faulted areas resemble terrestrial continents. Near large shield volcanoes, with dominant basaltic compositions, steep-sided domes have been interpreted as non-degassed silicic extrusions. The hypothesis of a granitic component is "tantalising". Extra-terrestrial granite is frequently found as clasts and mesostases in asteroidal meteorites. Porphyritic textures, with alkali feldspar crystals up to several centimetres in size, were observed in silicate enclaves within iron meteorites. In the chondrite clan, polymict breccias can contain granitic clasts, whose provenance is debated. One clast from the Adzhi-Bogdo meteorite yields a 4.53 ± 0.03 Ga Pb-Pb age, making it the oldest known granite in the solar system. The

  9. Hydrology of the Upper Capibaribe Basin, Pernambuco, Brazil - A reconnaissance in an Area of Crystalline Rocks

    Chada Filho, Luiz Goncalves; Dias Pessoa, Mario; Sinclair, William C.

    1966-01-01

    The upper Capibaribe basin is the western three-fourths, approximately, of the valley of the river that empties into the Atlantic Ocean at Recife, the capital of the State of Pernambuco, Brazil. It is the part of the drainage basin that is within the Drought Polygon of northeast Brazil, and it totals about 5,400 square kilometers. It receives relatively abundant precipitation in terms of the annual average, yet is regarded as hot subhumid to semiarid because the precipitation is uneven from year to year and place to place. The dependable water supply, therefore, is small. The basin has water, which could be put to better use than at present, but the opportunities for augmenting the usable supply are not great. The streams are intermittent and therefore cannot be expected to fill surface reservoirs and to keep them filled. The ground-water reservoirs have small capacity--quickly filled and quickly drained. A rough estimate based on the records for 1964 suggests that, of 4,700 million cubic meters of precipitation in the upper Capibaribe basin, 2,700 million cubic meters (57 percent) left the basin as runoff and 2,000 million cubic meters {43 percent) went into underground storage or was evaporated or transpired. The bedrock of the upper Capibaribe basin is composed of granite, gneiss, schist, and other varieties of crystalline rocks, which have only insignificant primary permeability. They are permeable mainly where fractured. The principal fracture zones, fortunately, are in the valleys, where water accumulates and can feed into them, but the volume of fractured rock is small in relation to the basin as a whole. A well in a large water-filled fracture zone may yield up to 20,000 liters per hour, but the average well yields less than one-fourth this amount, and some wells yield none. The saprolite, or weathered rock, is many meters thick at some places especially in the eastern half of the upper Capibaribe basin. It contains water locally, but ordinarily will yield

  10. Isotopic age determineations on granitic and gneissic rocks from the Ubendian-Usagaran System in southern Tanzania

    Priem, H.N.A.; Boelrijk, N.A.I.M.; Hebeda, E.H.; Verdurmen, E.A.Th.; Verschure, R.H.; Oen, I.S.; Westra, L.

    1979-01-01

    Isotopic age measurements on granites and gneisses are reported from the Ubendian-Usagaran System in southern Tanzania. For the Lukumburu-Wino Granites a Rb-Sr whole-rock isochron (9 points) of 1771 +- 145 Ma with initial 87 Sr/ 86 Sr of 0.704 +- 0.003 was obtained (γ 87 Rb = 1.42 10 -11 a -1 ; errors 95% confidence level). Two samples from neighbouring granites and three gneisses from the contact zone of the Lukumburu-Wino Granites also fit to this isochron; inclusion into the isochron calculation yields an age of 1747 +- 85 Ma with the same initial Sr composition. Five parts of a banded Usagaran gneiss sample produce an isochron of 589 +- 70 Ma with initial 87 Sr/ 86 Sr of 0.7194 +- 0.0005. This internal isochron is interpreted as reflecting Sr isotopic equilibration through the sample during the main phase (or one of the main phases) of the Pan-African thermotectonic episode. Rb-Sr and K-Ar ages of 17 micas show a general resetting by the Pan-African thermotectonic episode. The Rb-Sr ages of the muscovites and the biotites average 528 Ma and 463 Ma, respectively, and are interpreted as reflecting subsequent stages in the cooling history after the termination of the event. Biotites have K-Ar ages persistently higher than the corresponding Rb-Sr ages, possibly reflecting a high partial 40 Ar pressure through the crust during the resetting of the biotite K-Ar systems. (Auth.)

  11. Hydrogeologic characteristics of domains of sparsely fractured rock in the granitic Lac Du Bonnet Batholith, southeastern Manitoba, Canada

    Stevenson, D.R.; Kozak, E.T.; Davison, C.C.; Gascoyne, M.; Broadfoot, R.A.

    1996-06-01

    The hydrogeologic characteristics of the granitic Lac du Bonnet batholith in southeastern Manitoba have been studied since 1978, as part of AECL's program to assess the concept of disposing of Canada's nuclear fuel waste deep within plutonic rocks of the Canadian Shield (Davison et al. 1994a). These studies have included an extensive program of drilling, logging, testing, sampling and monitoring in 19 deep surface boreholes drilled at Grid areas located across the Lac du Bonnet batholith, at the Whiteshell Laboratory (WL), and in surface and underground boreholes at the Underground Research Laboratory (URL). Based on these investigations domains of low permeability, sparsely fractured rock (SFR) have been identified in the Lac du Bonnet batholith

  12. Quantifying elemental compositions of primary minerals from granitic rocks and saprolite within the Santa Catalina Mountain Critical Zone Observatory

    Lybrand, R. A.; Rasmussen, C.

    2011-12-01

    Granitic terrain comprises a significant area of the earth's land surface (>15%). Quantifying weathering processes involved in the transformation of granitic rock to saprolite and soil is central to understanding landscape evolution in these systems. The quantification of primary mineral composition is important for assessing subsequent mineral transformations and soil production. This study focuses on coupling detailed analysis of primary mineral composition to soil development across an array of field sites sampled from the Santa Catalina Mountain Critical Zone observatory (SCM-CZO) environmental gradient. The gradient spans substantial climate-driven shifts in vegetation, ranging from desert scrub to mixed conifer forests. The parent material is a combination of Precambrian and Tertiary aged granites and quartz diorite. Primary mineral type and composition are known to vary among the various aged granitic materials and this variability is hypothesized to manifest as significant variation in regolith forming processes across the SCM-CZO. To address this variability, the mineral composition and mineral formulae of rock and saprolite samples were determined by electron microprobe chemical analyses. The rocks were pre-dominantly quartz, biotite, muscovite, orthoclase and calcium/sodium-rich plagioclase feldspars. Trace minerals observed in the samples included sphene, rutile, zircon, garnet, ilmenite, and apatite. Mineral formulae from electron microprobe analyses were combined with quantitative x-ray diffraction (QXRD) and x-ray fluorescence (XRF) data to quantify both primary and secondary mineralogical components in soil profiles from each of the field sites. Further, electron microprobe analyses of <2mm mixed conifer saprolite revealed weathered plagioclase grains coated with clay-sized particles enriched in silica and aluminum (~25% and 15%, respectively), suggesting kaolin as the secondary phase. The coatings were interspersed within each plagioclase grain, a

  13. Study on dynamic behavior of a shaft excavation through a faulted crystalline rock mass

    Hashizume, Shigeru; Matsui, Hiroya; Horiuchi, Yasuharu; Hata, Koji; Akiyoshi, Kenji; Sato, Shin; Shibata, Chihoko; Niunoya, Sumio; Noda, Masaru

    2013-01-01

    The 'Mizunami Underground Research Laboratory' has been studying and developing engineering technology for deep underground applications. These applications are multifaceted and are categorized as development of design and construction planning technology, development construction technology, development of countermeasure technology, and development of technology for construction and operation security. In this report, the dynamic behavior of shaft and the surrounding rock mass has been studied with respect to rock mass displacement and stress, the effect of using a concrete liner and excavating through faulted crystalline rock. (author)

  14. Evidentiary requirements to identify potentially acceptable sites (PAS) in crystalline rock

    Comella, P.A.; Smith, B.H.

    1985-01-01

    This report contains information on the evidentiary requirements to identify potentially acceptable sites in crystalline rock for waste disposal. Topics addressed include: chronology, key regulatory assumptions, statutory framework for identifying potentially acceptable sites, application of 10 disqualifiers, consideration of favorable and potentially adverse conditions, a composite favorability analysis, and a proposed outline for PAS identification decision document

  15. Geochemical study of water-rock interaction processes on geothermal systems of alkaline water in granitic massif

    Buil gutierrez, B.; Garcia Sanz, S.; Lago San Jose, M.; Arranz Yague, E.; Auque Sanz, L.

    2002-01-01

    The study of geothermal systems developed within granitic massifs (with alkaline waters and reducing ORP values) is a topic of increasing scientific interest. These systems are a perfect natural laboratory for studying the water-rock interaction processes as they are defined by three main features: 1) long residence time of water within the system, 2) temperature in the reservoir high enough to favour reaction kinetics and finally, 3) the comparison of the chemistry of the incoming and outgoing waters of the system allows for the evaluation of the processes that have modified the water chemistry and its signature, The four geothermal systems considered in this paper are developed within granitic massifs of the Spanish Central Pyrenes; these systems were studied from a geochemical point of view, defining the major, trace and REE chemistry of both waters and host rocks and then characterizing the composition and geochemical evolution of the different waters. Bicarbonate-chloride-sodic and bicarbonate-sodic compositions are the most representative of the water chemistry in the deep geothermal system, as they are not affected by secondary processes (mixing, conductive cooling, etc). (Author)

  16. An analogue of long-term stability of flow-path structure in crystalline rocks distributed in the orogenic belt, Japan

    Yoshida, H. [Nagoya University, University Museum Material Research Section, 464-8601, Chikusa, Nagoya, 464-8601 (Japan)]. E-mail: dora@num.nagoya-u.ac.jp; Takeuchi, M. E-mail: takeuchi@eps.nagoya-u.ac.jp

    2004-07-01

    In the orogenic belt, in the Japanese islands, crystalline rocks from the youngest to older ages and of different orders have been identified which have formed massive areas. The fracture system observed within these rock masses implies that the groundwater and solute can be conducted through the fracture's network. It is expected that the nuclides can be retarded due to chemical sorption and/or physical retardation by the fracture fillings and fracture open pore geometry. Most of the evaluation framework of the nuclides retardation process in the geological disposal of high level radioactive waste (HLW) is, however, basically taken into account in the present geological state, without changes of structural and mineralogical features, and in its influence on the groundwater flow system over a long period of time. This paper seeks analogous evidence that can provide the confidence of such evaluation methodology and its long-term applicability. Here, we describe the fracture system developed in the crystalline rock with the different ages intruded in the orogenic belt in order to build the long-term fracturing and its 'stability' model. In particular, comparisons with the rock of 1.9-0.8 Ma Takidani Granodiorite (the youngest pluton in the world), ca. 67 Ma of Toki Granite and ca. 117 Ma Kurihashi Granodiorite located in central to northwest Japan suggest a unique characteristic of the fracture forming process and their relatively stable geometrical changing. This analogue enables us to provide a model to build the confidence of a safety context applicable for the geological setting under the orogenic field with a long-term scale. The model may also be useful for other stable tectonic settings as well as for a site characterisation methodology of crystalline rock for HLW geological disposal. (author)

  17. Validation of modeling team solution and matrix porosity of granitic rocks

    Vaněček, M.; Hanuš, R.; Doležalová, L.; Michálková, J.; Rousová, P.; Sosna, K.; Křížová, H.; Záruba, J.; Navrátil, Tomáš; Nakládal, P.; Brož, M.; Rohovec, Jan; Polák, M.; Milický, M.

    2008-01-01

    Roč. 34, 4/6 (2008), s. 1343396-1343396 ISSN 0161-6951. [International Geological Congress /33./. 06.08.2008-14.08.2008, Oslo] R&D Projects: GA MPO 1H-PK/31 Institutional research plan: CEZ:AV0Z30130516 Keywords : radioactive waste * granite * hydrogeology * model ing * porosity Subject RIV: DD - Geochemistry

  18. Creep in crystalline rock with application to high level nuclear waste repository

    Eloranta, P.; Simonen, A.

    1992-06-01

    The time-dependent strength and deformation properties of hard crystalline rock are studied. Theoretical models defining the phenomena which can effect these properties are reviewed. The time- dependent deformation of the openings in the proposed nuclear waste repository is analysed. The most important factors affecting the subcritical crack growth in crystalline rock are the stress state, the chemical environment, temperature and microstructure of the rock. There are several theoretical models for the analysis of creep and cyclic fatigue: deformation diagrams, rheological models thermodynamic models, reaction rate models, stochastic models, damage models and time-dependent safety factor model. They are defective in describing the three-axial stress condition and strength criteria. In addition, the required parameters are often too difficult to determine with adequate accuracy. Therefore these models are seldom applied in practice. The effect of microcrack- driven creep on the stability of the work shaft, the emplacement tunnel and the capsulation hole of a proposed nuclear waste repository was studied using a numerical model developed by Atomic Energy of Canada Ltd. According to the model, the microcrack driven creep progresses very slowly in good quality rock. Poor rock quality may accelerate the creep rate. The model is very sensitive to the properties of the rock and secondary stress state. The results show that creep causes no stability problems on excavations in good rock. The results overestimate the effect of the creep, because the analysis omitted the effect of support structures and backfilling

  19. Construction of full-scale shaft seals in crystalline rock

    Martino, J.B.; Dixon, D.A.; Onagi, D.; Kim, C-S; Holowick, B. [Atomic Energy of Canada Limited, Pinawa, MB (Canada)

    2011-07-01

    The Underground Research Laboratory (URL) was constructed to investigate concepts related to geological disposal of used nuclear fuel. This involved investigating the rock mass by undertaking in situ experiments using a multi disciplinary technical approach. The decision was made in 2003 to close the URL. Part of the closure process involved installing seals in the access and ventilation shafts at locations where they intersected an ancient thrust fault (Fracture Zone 2 -- FZ2). FZ2 is an active hydraulic pathway in the Lac du Bonnet batholith and this feature is the dominating structural and hydrogeological feature at the URL site. Above FZ2 the groundwater has a low salinity and is dominated by surface-related processes. With increasing depth in the batholith, surface-related effects decrease and the salinity of the groundwater increases to 90 g/L total dissolved solids. The decision to install the seals was made as part of the due diligence for the site closure to ensure that the saline groundwater located at depth down strike and below the thrust fault would not enter the closed underground openings and mix with less saline shallow groundwater. The construction of each seal involved the installation of a heavily reinforced low alkalinity concrete component keyed into the surrounding rock. The concrete supported and restrained a central clay-sand component, which was capped by an unreinforced concrete component. The clay-sand component spans the exposure of the thrust fault in each shaft. This paper describes the construction of the main shaft seal and the ventilation shaft seal. The construction of the shaft seals at the URL was part of the Nuclear Legacy Liabilities Program (NLLP) being funded by Natural Resources Canada (NRCan). (author)

  20. Construction of full-scale shaft seals in crystalline rock

    Martino, J.B.; Dixon, D.A.; Onagi, D.; Kim, C-S; Holowick, B.

    2011-01-01

    The Underground Research Laboratory (URL) was constructed to investigate concepts related to geological disposal of used nuclear fuel. This involved investigating the rock mass by undertaking in situ experiments using a multi disciplinary technical approach. The decision was made in 2003 to close the URL. Part of the closure process involved installing seals in the access and ventilation shafts at locations where they intersected an ancient thrust fault (Fracture Zone 2 -- FZ2). FZ2 is an active hydraulic pathway in the Lac du Bonnet batholith and this feature is the dominating structural and hydrogeological feature at the URL site. Above FZ2 the groundwater has a low salinity and is dominated by surface-related processes. With increasing depth in the batholith, surface-related effects decrease and the salinity of the groundwater increases to 90 g/L total dissolved solids. The decision to install the seals was made as part of the due diligence for the site closure to ensure that the saline groundwater located at depth down strike and below the thrust fault would not enter the closed underground openings and mix with less saline shallow groundwater. The construction of each seal involved the installation of a heavily reinforced low alkalinity concrete component keyed into the surrounding rock. The concrete supported and restrained a central clay-sand component, which was capped by an unreinforced concrete component. The clay-sand component spans the exposure of the thrust fault in each shaft. This paper describes the construction of the main shaft seal and the ventilation shaft seal. The construction of the shaft seals at the URL was part of the Nuclear Legacy Liabilities Program (NLLP) being funded by Natural Resources Canada (NRCan). (author)

  1. Application of NURE data to the study of crystalline rocks in the Wyoming uranium province

    Rush, S.M.; Anderson, J.R.; Bennett, J.E.

    1983-03-01

    The Wyoming uranium province study is a part of the National Uranium Resource Evaluation (NURE) program conducted by Bendix Field Engineering Corporation for the US Department of Energy. The ultimate objective of the entire project is the integration of NURE and other data sources to develop a model for a uranium province centered in Wyoming. This paper presents results of the first phase of the Wyoming uranium province study, which comprises characterization of the crystalline rocks of the study area using NURE hydrogeochemical and stream-sediment data, aerial radiometric and magnetic data, and new data generated for zircons from intrusive rocks in the study area. The results of this study indicate that the stream-sediment, aerial radiometric, aerial magnetic, and zircon data are useful in characterization of the crystalline rocks of the uranium province. The methods used in this project can be applied in two ways toward the recognition of a uranium province: (1) to locate major uranium deposits and occurrences, and (2) to generally identify different crystalline rock types, particularly those that could represent significant uranium source rocks. 14 figures, 8 tables

  2. International collaboration on used fuel disposition crystalline rocks

    Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gardner, Payton [Univ. of Montana, Missoula, MT (United States); Kim, Geon-Young [Korean Atomic Energy Research Inst. Daejeon (Korea); Ji, Sung-Hoon [Korean Atomic Energy Research Inst., Daejeon (Korea)

    2016-08-01

    Active participation in international R&D is crucial for achieving the UFD long-term goals of conducting “experiments to fill data needs and confirm advanced modeling approaches” (by 2015) and of having a “robust modeling and experimental basis for evaluation of multiple disposal system options” (by 2020). DOE’s Office of Nuclear Energy (NE) and its Office of Used Fuel Disposition Research and Development (UFD) have developed a strategic plan to advance cooperation with international partners. The international collaboration on the evaluation of crystalline disposal media at Sandia National Laboratories (SNL) in FY16 focused on the following four activities: (1) thermal-hydrologic-mechanical-chemical modeling single fracture evolution; (2) simulations of flow and transport in Bedrichov Tunnel, Czech Republic, (3) completion of streaming potential testing at Korean Atomic Energy Research Institute (KAERI), and (4) technical data exchange with KAERI on thermal-hydrologic-mechanical (THM) properties and specifications of bentonite buffer materials. The first two activities are part of the Development of Coupled Models and their Validation against Experiments (DECOVALEX-2015) project.

  3. Fracture detection in crystalline rock using ultrasonic reflection techniques: Volume 1

    Palmer, S.P.

    1982-11-01

    This research was initiated to investigate using ultrasonic seismic reflection techniques to detect fracture discontinuities in a granitic rock. Initial compressional (P) and shear (SH) wave experiments were performed on a 0.9 x 0.9 x 0.3 meter granite slab in an attempt to detect seismic energy reflected from the opposite face of the slab. It was found that processing techniques such as deconvolution and array synthesis could improve the standout of the reflection event. During the summers of 1979 and 1980 SH reflection experiments were performed at a granite quarry near Knowles, California. The purpose of this study was to use SH reflection methods to detect an in situ fracture located one to three meters behind the quarry face. These SH data were later analyzed using methods similar to those applied in the laboratory. Interpretation of the later-arriving events observed in the SH field data as reflections from a steeply-dipping fracture was inconclusive. 41 refs., 43 figs., 7 tabs

  4. Rock-water interaction involving uranium and thorium isotopes in the fractures of El Berrocal granite, Spain

    Ivanovich, M.; Cahmbers, N.; Hernandez-Benitez, A.

    1996-01-01

    In the framework of a number of R and D programmes, low permeability rocks in which the groundwater flow is governed by fractures are being considered as potentially suitable candidates for the long-term storage of radioactive waste at depth [1]. Such rocks are often one of the main sources of the radionuclides deriving from the natural radioactive decay chains headed by U and Th. This characteristic makes this type of rock very useful in providing geochemical analogues for the behaviour of transuranic radionuclides present in the nuclear waste [2,3]. The main aim of the work reported here is to study in detail the distribution of naturally occurring radionuclides in several types of fracture infill material from the El Berrocal granitic pluton. The pluton in situated at the southern edge of the Spanish Central System and contains a uranium-mineralized quartz vein (UQV) that has been mined for uranium in the past [4]. Groundwaters as well as natural colloids have been sampled from some of the boreholes with the ultimate intention to model rock/water interaction processes which may take place in the water-bearing fractures in the batholith. The second aim of this work has been to date some of the calcite-rich fracture infills derived from the drill cores at depth, especially at water-bearing horizons. (Author)

  5. Geohydromechanical Processes in the Excavation Damaged Zone in Crystalline Rock, Rock Salt, and Indurated and Plastic Clays

    Tsang, Chin-Fu; Bernier, Frederic; Davies, Christophe

    2004-01-01

    The creation of an excavation disturbed zone or excavation damaged zone is expected around all man-made openings in geologic formations. Macro- and micro-fracturing, and in general a redistribution of in situ stresses and rearrangement of rock structures, will occur in this zone, resulting in drastic changes of permeability to flow, mainly through the fractures and cracks induced by excavation. Such an EDZ may have significant implications for the operation and long-term performance of an underground nuclear waste repository. Various issues of concern need to be evaluated, such as processes creating fractures in the excavation damaged zone, the degree of permeability increase, and the potential for sealing or healing (with permeability reduction) in the zone. In recent years, efforts along these lines have been made for a potential repository in four rock types-crystalline rock, salt, indurated clay, and plastic clay-and these efforts have involved field, laboratory, and theoretical studies. The present work involves a synthesis of the ideas and issues that emerged from presentations and discussions on EDZ in these four rock types at a CLUSTER Conference and Workshop held in Luxembourg in November, 2003. First, definitions of excavation disturbed and excavation damaged zones are proposed. Then, an approach is suggested for the synthesis and intercomparison of geohydromechanical processes in the EDZ for the four rock types (crystalline rock, salt, indurated clay, and plastic clay). Comparison tables of relevant processes, associated factors, and modeling and testing techniques are developed. A discussion of the general state-of-the-art and outstanding issues are also presented. A substantial bibliography of relevant papers on the subject is supplied at the end of the paper

  6. Emplacement mechanisms and structural influences of a younger granite intrusion into older wall rocks - a principal study with application to the Goetemar and Uthammar granites. Site-descriptive modelling SDM-Site Laxemar

    Cruden, Alexander R.

    2008-12-01

    The c. 1.80 Ga old bedrock in the Laxemar-Simpevarp area, which is the focus of the site investigation at Oskarshamn, is dominated by intrusive rocks belonging to the c. 1.86-1.65 Ga Transscandinavian Igneous Belt (TIB). However, the site investigation area is situated in between two c. 1.45 Ga old anorogenic granites, the Goetemar granite in the north and the Uthammar granite in the south. This study evaluates the emplacement mechanism of these intrusions and their structural influence on the older bedrock. Field observations and structural measurements indicate that both the Goetemar and the Uthammar granites are discordant and have not imposed any significant ductile deformation on their wall-rocks. The apparent conformity of geological contacts and fabrics in the wall rocks and the southern margin of the Goetemar granite is coincidental and inherited from the pattern of Svecokarelian deformation of the TIB. However, interpretation of regional aeromagnetic data suggests that the granites occur within a broad, NNE-SSW trending linear belt, pointing to deep seated tectonic control on their generation, ascent and emplacement. Thermochronology indicates that the granites were emplaced at depths between 4 and 8 km into brittle wall rocks. The 3-D shape of the Goetemar and Uthammar plutons has been investigated by 2.75D forward modelling of the residual gravity anomalies due to both granites. Both granites are associated with strong residual gravity anomalies of up to -10 mgal. Constraints on the geometry of the plutons at the surface are provided from surface geology maps and several deep boreholes located on or close to the model profiles. A further variable in the gravity modelling is introduced by either allowing the upper contact of the plutons to assume the most suitable orientation to produce the best fit between the modelled and observed gravity ('unconstrained models') or by forcing the near surface orientation of the contacts to be vertical ('constrained

  7. Emplacement mechanisms and structural influences of a younger granite intrusion into older wall rocks - a principal study with application to the Goetemar and Uthammar granites. Site-descriptive modelling SDM-Site Laxemar

    Cruden, Alexander R. (Dept. of Geology, Univ. of Toronto (Canada))

    2008-12-15

    The c. 1.80 Ga old bedrock in the Laxemar-Simpevarp area, which is the focus of the site investigation at Oskarshamn, is dominated by intrusive rocks belonging to the c. 1.86-1.65 Ga Transscandinavian Igneous Belt (TIB). However, the site investigation area is situated in between two c. 1.45 Ga old anorogenic granites, the Goetemar granite in the north and the Uthammar granite in the south. This study evaluates the emplacement mechanism of these intrusions and their structural influence on the older bedrock. Field observations and structural measurements indicate that both the Goetemar and the Uthammar granites are discordant and have not imposed any significant ductile deformation on their wall-rocks. The apparent conformity of geological contacts and fabrics in the wall rocks and the southern margin of the Goetemar granite is coincidental and inherited from the pattern of Svecokarelian deformation of the TIB. However, interpretation of regional aeromagnetic data suggests that the granites occur within a broad, NNE-SSW trending linear belt, pointing to deep seated tectonic control on their generation, ascent and emplacement. Thermochronology indicates that the granites were emplaced at depths between 4 and 8 km into brittle wall rocks. The 3-D shape of the Goetemar and Uthammar plutons has been investigated by 2.75D forward modelling of the residual gravity anomalies due to both granites. Both granites are associated with strong residual gravity anomalies of up to -10 mgal. Constraints on the geometry of the plutons at the surface are provided from surface geology maps and several deep boreholes located on or close to the model profiles. A further variable in the gravity modelling is introduced by either allowing the upper contact of the plutons to assume the most suitable orientation to produce the best fit between the modelled and observed gravity ('unconstrained models') or by forcing the near surface orientation of the contacts to be vertical (&apos

  8. THE STUDY OF GAS MIGRATION IN CRYSTALLINE ROCK USING INJECTION TESTS

    Jiří Svoboda

    2012-07-01

    Full Text Available The study of gas migration in crystalline rock using injection tests is being carried out in the frame of the FORGE (Fate of Repository Gases project. The Czech Technical University in Prague (CTU, Centre of Experimental Geotechnics (CEG is participating in WP4 which is focused on disturbed host rock formations with respect to radioactive waste deep repositories. A series of in-situ tests is being conducted at the Josef Underground Laboratory. The aim of the testing is to simulate and study phenomena that might lead to gas-driven radionuclide transport in fractured crystalline rock. The in-situ tests combine migration and large-scale gas injection measurements; gas injection tests are being employed for the study of gas transport. For the purposes of comparison of the behaviour of the rock mass with regard to air and water a series of water pressure tests are also being carried out. The quality of the rock mass is assessed using rock mass classification systems.

  9. Phenomenological study on crystalline rock for evaluating of long-term behavior (Contract research)

    Okubo, Seisuke; Fukui, Katsunori; Hashiba, Kimihiro; Hikima, Ryoichi; Tanno, Takeo; Sanada, Hiroyuki; Matsui, Hiroya; Sato, Toshinori

    2012-02-01

    Rock, under in situ conditions, shows time-dependent behavior such as creep/relaxation. With respect to high-level radioactive waste disposal, knowledge of the long-term mechanical stability of shafts and galleries excavated in rock is required, not only during construction and operation but also over a period of thousands of years after closure. Therefore, it is very important to understand the time-dependent behavior of rock for evaluating long-term mechanical stability. The purpose of this study is determining the mechanisms of time-dependent behavior of rock by precise testing, observation and measurement in order to develop methods for evaluating long-term mechanical stability of a rock mass. In the previous work, testing techniques have been established and basic evaluation methods were developed. Recently, some parameters needed for simulation of time-dependent behavior were determined at the Mizunami underground research facilities. However, sufficient data to check the reliability of the evaluation method for these parameters were not available. This report describes the results of the activities in fiscal year 2010. In Chapter 1, we provide an overview and the background to this study. In Chapter 2, the results of a long-term creep test on Tage tuff, started in fiscal year 1997 are described. In Chapter 3, the relation of loading-rate dependency of strength and stress dependency of creep life, the relation of time dependency, probability distribution and size effects are discussed to indicate more clearly the meaning of the value of 'n' to express the degree of time dependency of the rock. Furthermore, past studies concerning the value of 'n' are reviewed and the tests that could be carried out in future studies of mechanical properties and time dependency of Toki granite are considered in this Chapter. In Chapter 4, failure criterions of a rock mass considering time dependency are discussed. In Chapter 5, the FEM analysis implemented with a generalized

  10. Evaluation of the basic mechanical and thermal properties of deep crystalline rocks

    Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Jeon, Seok Won

    2001-04-01

    This report provides the mechanical and thermal properties of granitic intact rocks obtained from Deep Core Drilling Program which is carried out as part of the assessment of deep geological environmental condition. These data are the basic material properties of the core samples from the boreholes drilled up to 500 m depth at the Yusung and Kosung sites. These sites were selected based on the result of preliminary site evaluation study. In this study, the mechanical properties include density, porosity, P-wave velocity, S-wave velocity, uniaxial compressive strength, Young's modulus, Poisson's ratio, tensile strength, and shear strength of fractures, and the thermal properties are heat conductivity, thermal expansion coefficient, specific heat and so on. Those properties were measured through laboratory tests and these data are compared with the existing test results of several domestic rocks

  11. Evaluation of the basic mechanical and thermal properties of deep crystalline rocks

    Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Jeon, Seok Won

    2001-04-01

    This report provides the mechanical and thermal properties of granitic intact rocks obtained from Deep Core Drilling Program which is carried out as part of the assessment of deep geological environmental condition. These data are the basic material properties of the core samples from the boreholes drilled up to 500 m depth at the Yusung and Kosung sites. These sites were selected based on the result of preliminary site evaluation study. In this study, the mechanical properties include density, porosity, P-wave velocity, S-wave velocity, uniaxial compressive strength, Young's modulus, Poisson's ratio, tensile strength, and shear strength of fractures, and the thermal properties are heat conductivity, thermal expansion coefficient, specific heat and so on. Those properties were measured through laboratory tests and these data are compared with the existing test results of several domestic rocks.

  12. Phenomenological study on crystalline rock for evaluating of long-term behavior (Contract research)

    Okubo, Seisuke; Seno, Yasuhiro; Hirano, Toru; Matsui, Hiroya; Nakama, Shigeo

    2008-08-01

    The Japan Atomic Energy Agency (JAEA) is conducting the Mizunami Underground Research Laboratory (MIU) Project in order to develop comprehensive geological investigation and engineering techniques for deep underground applications (e.g. repository of HLW). The purpose of this study is to contribute to the evaluation of the mechanical stability of a research drift and to plan the future studies. Rock shows time-dependent behavior such as creep/relaxation. For the shaft and gallery of the geological disposal for the radioactive waste, the mechanical stability over a period of thousands of years is demanded not only during construction and operation but also after back-filling. So, to understand the time-dependent behavior of rock is very important for evaluating the long-term mechanical stability. This study is aiming to find out the mechanism of time-dependent behavior of rock such as creep by the precision test, observation and measurement, to develop the evaluating method of long-term behavior of rock mass, and to get the information for planning the study of the Phase III (Operation Phase) at the Mizunami URL. In the previous work conducted before this fiscal year 2007, we improved the testing technique and started test of Toki granite sampled from target site. Furthermore we studied the in-situ measurement method for evaluating the scatter of rock properties. This report describes the results of the works in the fiscal year 2007. In Chapter 1, we described the overview and background of this study. In Chapter 2, the result of continuing creep test of Tage tuff which was started from the fiscal year 1997 was described. Although there was some annual variability, the precious data were obtained. In Chapter 3, the control program for the generalized relaxation test was developed. The generalized relaxation test of Toki granite was conducted in order to get basically data. In Chapter 4, the extended constitutive equation of variable compliance was analytically

  13. Theoretical study on crystalline rock for evaluating of long-term behavior (Contract research)

    Ichikawa, Yasuaki; Seno, Yasuhiro; Sato, Toshinori; Nakama, Shigeo

    2008-03-01

    The Japan Atomic Energy Agency (JAEA) is working on the Project of Mizunami Underground Research Laboratory (MIU). The project aims at developing comprehensive techniques of geological investigation and of construction of deep underground space for a repository of HLW and/or TRU. This study contributes to an estimation of long-term stability of underground spaces. Rock materials commonly show time-dependent behavior such as creep and relaxation. The underground structures for geological disposal of radioactive wastes must keep stable not only during construction and operation but also after closing, and then the long-term stability of rock structures (over thousands of years) is essentially important for designing the structures. The true mechanism of time-dependent behavior of rock materials is not yet clearly understood, though the phenomena are widely known. This study aims at elucidating the scientific truth involved in the time-dependent behavior of rock showing creep and relaxation. We used samples of Toki granite and performed precise tests under laser microscope observation, and then developed theories representing the experimental results. These experimental and theoretical results will be served for the design and construction of the Phase III (Operation Phase) of the MIU Project. This is the report worked out in the fiscal year 2006. In this work we performed the following subjects: 1) Uniaxial and stress relaxation tests under observation of a confocal laser scanning microscope (CLSM) by using granite specimens of MIU. 2) Pressure dissolution experiment by using specimens of single crystal quartz and glass beads. 3) Development of the rate of pressure dissolution of quartz and a homogenization analysis for quartz dissolution. In Chapter 2 CLSM was used to acquire clear three-dimensional images of Mizunami granite specimens for uniaxial and stress relaxation tests, and observed the change of microscale structure including the mineral configuration under

  14. Occurrence of springs in massifs of crystalline rocks, northern Portugal

    Pacheco, Fernando António Leal; Alencoão, Ana Maria Pires

    2002-02-01

    An inventory of artesian springs emerging from fractures (fracture springs) was conducted in the Pinhão River Basin and Morais Massif, northern Portugal, comprising an area of approximately 650 km2. Over 1,500 springs were identified and associated with geological domains and fracture sets. Using cross-tabulation analysis, spring distributions by fracture sets were compared among geological environments, and the deviations related to differences in rock structure and, presumably, to differences in deformational histories. The relation between spring frequencies and rock structures was further investigated by spectral determination, the model introduced in this study. Input data are the spring frequencies and fracture lengths in each geological domain, in addition to the angles between fracture strikes and present-day stress-field orientation (θ). The model's output includes the so-called intrinsic densities, a parameter indexing spring occurrence to factors such as fracture type and associated deformational regime and age. The highest densities (12.2 springs/km of lineament) were associated with young shear fractures produced by brittle deformation, and the lowest (0.1) with old tensional and ductile fractures. Spectral determination also relates each orientation class to a dominant structural parameter: where spring occurrence is controlled by θ, the class is parallel to the present-day stress-field orientation; where the control is attributed to the length of fractures, the spring occurrence follows the strike of large-scale normal faults crossing the region. Résumé. Un inventaire des sources artésiennes émergeant de fractures (sources de fractures) a été réalisé dans le bassin de la rivière Pinhão et dans le massif de Morais, dans le nord du Portugal, dans une région couvrant environ 650 km2. Plus de 1,500 sources ont été identifiées et associées à des domaines géologiques et à des ensembles de fractures. Grâce à une analyse de tableaux

  15. Quality of water from crystalline rock aquifers in New England, New Jersey, and New York, 1995-2007

    Flanagan, Sarah M.; Ayotte, Joseph D.; Robinson, Gilpin R.

    2012-06-25

    Crystalline bedrock aquifers in New England and parts of New Jersey and New York (NECR aquifers) are a major source of drinking water. Because the quality of water in these aquifers is highly variable, the U.S. Geological Survey (USGS) statistically analyzed chemical data on samples of untreated groundwater collected from 117 domestic bedrock wells in New England, New York, and New Jersey, and from 4,775 public-supply bedrock wells in New England to characterize the quality of the groundwater. The domestic-well data were from samples collected by the USGS National Water-Quality Assessment (NAWQA) Program from 1995 through 2007. The public-supply-well data were from samples collected for the U.S. Environmental Protection Agency (USEPA) Safe Drinking Water Act (SDWA) Program from 1997 through 2007. Chemical data compiled from the domestic wells include pH, specific conductance, dissolved oxygen, alkalinity, and turbidity; 6 nitrogen and phosphorus compounds, 14 major ions, 23 trace elements, 222radon gas (radon), 48 pesticide compounds, and 82 volatile organic compounds (VOCs). Additional samples were collected from the domestic wells for the analysis of gross alpha- and gross beta-particle radioactivity, radium isotopes, chlorofluorocarbon isotopes, and the dissolved gases methane, carbon dioxide, nitrogen, and argon. Chemical data compiled from the public-supply wells include pH, specific conductance, nitrate, iron, manganese, sodium, chloride, fluoride, arsenic, uranium, radon, combined radium (226radium plus 228radium), gross alpha-particle radioactivity, and methyl tert-butyl ether (MtBE).Patterns in fluoride, arsenic, uranium, and radon distributions were discernable when the data were compared to lithology groupings of the bedrock, indicating that the type of bedrock has an effect on the quality of groundwater from NECR aquifers. Fluoride concentrations were significantly higher in groundwater samples from the alkali granite, peraluminous granite, and

  16. Geochronology of the Swift Current granite and host volcanic rocks of the Love Cove group, southwestern Avalon zone, Newfoundland

    Dallmeyer, R.D.; O'Driscoll, C.F.; Hussey, E.M.

    1981-01-01

    Zircon fractions from the variably deformed and metamorphosed Swift Current granite and host volcanic rocks of the Love Cove Group record individually discordant U-Pb ages with well-defined upper concordia intercept ages of 580 +- 20 and 590 +- 30 Ma, respectively. These are interpreted to be crystallization dates and indicate a late Proterozoic cogmagmatic relationship. Primary hornblende from the pluton record disturbed 40 Ar/ 39 Ar age spectra that suggest postcrystallization argon loss, probably during Acadian (Devonian) regional metamorphism. 40 Ar/ 39 Ar plateau ages of 560-566 Ma are well defined for the hornblende and are interpreted to date times of postmagmatic cooling. The similarity between zircon and hornblende dates suggests relatively rapid postmagmatic cooling. A six-point, Rb-Sr whole-rock isochron age of 548 +- 11 Ma is defined for the pluton. The slight discordancy of this date in comparison with the zircon and hornblende ages may reflect a minor disturbance of whole-rock isotopic systems during Acadian regional metamorphism. (author)

  17. Results of Rb-Sr dating of metamorphic rocks of crystalline complexes of Male Karpaty Mts

    Bagdasaryan, G.P.; Gukasyan, P.Kh.; Cambel, B.; Veselsky, J.

    1983-01-01

    The paper follows up on a recently published paper on Rb-Sr isochrone dating of granitoid rocks of the Male Karpaty Mts. Data are given on comparative statistical analysis of isochrones obtained for the Bratislava and Modra massifs (isochrone of the latter is complemented with the analyses of two new samples) and the results of age determination of metasedimentary rocks of the Pezinok-Pernek zone and the Bratislava area by the Rb-Sr isochrone. Regression analysis shows that there is no statistically significant difference between the age of the Bratislava massif (347+-4 m.y.) and the Modra massif (326+-22 m.y.) and between their initial ratios 87 Sr/ 86 Sr (i.e., they are synchronous, having the same magma source) which makes it possible to calculate uniform value for age. Whole-rock samples of metamorphic and crystalline schists (gneisses) of the Male Karpaty Mts. also determine the isochrone corresponding to the age 387+-38 m.y. (2σ) and initial ratio ( 87 Sr/ 86 Sr)=0.7100+-0.00O8 (2σ). Rb-Sr isotope analyses of several pairs of biotite-crystalline schist (from which biotite was separated) point out that redistribution of Sr isotopes among the mineral phases of rocks takes place during the periplutonic metamorphism, while the whole-rock samples remain chemically closed systems. (author)

  18. Geochemistry of rare earths and oxygen isotopes in granitic rocks from Monte das Gameleiras and Dona Ines, Rio Grande do Norte-Paraiba border, Brazil

    Sial, A.N.

    1984-01-01

    The study of oxygen isotopes and rare earth elements in granitic plutons of Monte das Gameleiras and Dona Ines, Rio Grande do Norte-Paraiba border, in Brazil, to define the nature of source rock of progenitor magmas, is presented. (M.C.K.) [pt

  19. A revised conceptual hydrogeologic model of a crystalline rock environment, Whiteshell research area, southeastern Manitoba, Canada

    Stevenson, D.R.; Brown, A.; Davison, C.C.; Gascoyne, M.; McGregor, R.G.; Ophori, D.U.; Scheier, N.W.; Stanchell, F.; Thorne, G.A.; Tomsons, D.K.

    1996-04-01

    A revised conceptual hydrogeologic model of regional groundwater flow in the crystalline rocks of the Whiteshell Research Area (WRA) has been developed by a team of AECL geoscientists. The revised model updates an earlier model developed in 1985, and has a much broader database. This database was compiled from Landsat and airborne radar images, geophysical surveys and surface mapping, and from analyses of fracture logs, hydraulic tests and water samples collected from a network of deep boreholes drilled across the WRA. The boundaries of the revised conceptual model were selected to coincide with the natural hydraulic boundaries assumed for the regional groundwater flow systems in the WRA. The upper and lower boundaries are the water table and a horizontal plane 4 km below ground surface. For modelling purposes the rocks below 4 km are considered to be impermeable. The rocks of the modelled region were divided on the basis of fracture characteristics into three categories: fractured zones (FZs); moderately fractured rock (MFR); and sparsely fractured rock (SFR). The FZs are regions of intensely fractured rock. Seventy-six FZs were selected to form the fault framework within the revised conceptual model. The physical rock/water properties of the FZs, MFR and SFR were selected by analysis of field data from hydraulic and tracer tests, laboratory test data and water quality data. These properties were used to define a mathematical groundwater flow model of the WRA using AECL's MOTIF finite element code (Ophori et al. 1995, 1996). (author). 29 refs., 4 tabs., 12 figs

  20. Raw data from orientation studies in crystalline rock areas of the southeastern United States

    Price, V.

    1976-03-01

    Raw data are presented on orientation studies conducted in crystalline rock areas of the Southeast which were chosen because of published references to uranium mineralization. Preliminary data for four orientation study areas are included. These areas are Lamar County, Georgia; Oconee County, South Carolina; Brush Creek, North Carolina; and North Harper, North Carolina. Sample locality maps, tables of field data, and tables of analytical data are included for each study area

  1. Groundwater quality in the Piedmont and Blue Ridge crystalline-rock aquifers, eastern United States

    Lindsey, Bruce

    2017-12-07

    Groundwater provides nearly 50 percent of the Nation’s drinking water. To help protect this vital resource, the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Project assesses groundwater quality in aquifers that are important sources of drinking water (Burow and Belitz, 2014). The Piedmont and Blue Ridge crystalline-rock aquifers constitute one of the important areas being evaluated.

  2. Interpretation of field experiments on the flow of water and tracers through crystalline rock

    Hodgkinson, D.P.; Lever, D.A.; Robinson, P.C.; Bourke, P.J.

    1983-01-01

    This paper reviews recent work at Harwell on the interpretation of field experiments on the flow of water and tracers through crystalline rock. First a model for the radial transport of tracers through an isolated fracture is outlined and used to analyse a recent Swedish experiment at Finnsjoen. Secondly, the theoretical and experimental approach that is being used to quantify flow and dispersion through networks of fractures is described

  3. Pre-impact tectonothermal evolution of the crystalline basement-derived rocks in the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure

    Gibson, R.L.; Townsend, G.N.; Horton, J. Wright; Reimold, W.U.

    2009-01-01

    Pre-impact crystalline rocks of the lowermost 215 m of the Eyreville B drill core from the Chesapeake Bay impact structure consist of a sequence of pelitic mica schists with subsidiary metagraywackes or felsic metavolcanic rocks, amphibolite, and calc-silicate rock that is intruded by muscovite (??biotite, garnet) granite and granite pegmatite. The schists are commonly graphitic and pyritic and locally contain plagioclase porphyroblasts, fi brolitic sillimanite, and garnet that indicate middle- to upper-amphibolite-facies peak metamorphic conditions estimated at ??0.4-0.5 GPa and 600-670 ??C. The schists display an intense, shallowly dipping, S1 composite shear foliation with local micrometer- to decimeter-scale recumbent folds and S-C' shear band structures that formed at high temperatures. Zones of chaotically oriented foliation, resembling breccias but showing no signs of retrogression, are developed locally and are interpreted as shear-disrupted fold hinges. Mineral textural relations in the mica schists indicate that the metamorphic peak was attained during D1. Fabric analysis indicates, however, that subhorizontal shear deformation continued during retrograde cooling, forming mylonite zones in which high-temperature shear fabrics (S-C and S-C') are overprinted by progressively lower- temperature fabrics. Cataclasites and carbonate-cemented breccias in more competent lithologies such as the calc-silicate unit and in the felsic gneiss found as boulders in the overlying impactite succession may refl ect a fi nal pulse of low-temperature cataclastic deformation during D1. These breccias and the shear and mylonitic foliations are cut by smaller, steeply inclined anastomosing fractures with chlorite and calcite infill (interpreted as D2). This D2 event was accompanied by extensive chlorite-sericitecalcite ?? epidote retrogression and appears to predate the impact event. Granite and granite pegmatite veins display local discordance to the S1 foliation, but elsewhere

  4. Tectonic constraints on a deep-seated rock slide in weathered crystalline rocks

    Borrelli, Luigi; Gullà, Giovanni

    2017-08-01

    Deep-seated rock slides (DSRSs), recognised as one of the most important mass wasting processes worldwide, involve large areas and cause several consequences in terms of environmental and economic damage; they result from a complex of controlling features and processes. DSRSs are common in Calabria (southern Italy) where the complex geo-structural setting plays a key role in controlling the geometry of the failure surface and its development. This paper describes an integrated multi-disciplinary approach to investigate a DSRS in Palaeozoic high-grade metamorphic rocks of the Sila Massif; it focuses on the definition of the internal structure and the predisposing factors of the Serra di Buda landslide near the town of Acri, which is a paradigm for numerous landslides in this area. An integrated interdisciplinary study based on geological, structural, and geomorphological investigations-including field observations of weathering grade of rocks, minero-petrographic characterisations, geotechnical investigations and, in particular, fifteen years of displacement monitoring-is presented. Stereoscopic analysis of aerial photographs and field observations indicate that the Serra di Buda landslide consists of two distinct compounded bodies: (i) an older and dormant body ( 7 ha) and (ii) a more recent and active body ( 13 ha) that overlies the previous one. The active landslide shows movement linked to a deep-seated translational rock slide (block slide); the velocity scale ranges from slow (1.6 m/year during paroxysmal stages) to extremely slow (affected by weathering processes that significantly reduce the rock strength and facilitate the extensive failure of the Serra di Buda landslide. Finally, the landslide's internal structure, according to geotechnical investigations and displacement monitoring, is proposed. The proposed approach and the obtained results can be generalised to typify other deep landslides in similar geological settings.

  5. Water-level fluctuations due to Earth tides in a well pumping from slightly fractured crystalline rock

    Marine, I.W.

    1975-01-01

    At the Savannah River plant of the Atomic Energy Commission near Aiken, South Carolina, there are three distinct groundwater systems: the coastal plain sediments, the crystalline metamorphic rocks, and a buried Triassic basin. The coastal plain sediments include several Cretaceous and Tertiary granular aquifers and aquicludes, the total thickness being about 305 m. Below these sediments, water occurs in small fractures in crystalline metamorphic rock (hornblende schist and gneiss with lesser amounts of quartzite). Water level fluctuations due to earth tides are recorded in the crystalline metamorphic rock system and in the coastal plain sediments. No water level fluctuations due to earth tides have been observed in wells in the Triassic rock because of the very low permeability. The water level fluctuations due to earth tides in the crystalline rock are about 10 cm, and those in the sediments are about 1.8 cm. The use of water level fluctuations due to earth tides to calculate porosity appears to present practical difficulties both in the crystalline metamorphic rock system and in the coastal plain sediments. In a 1-yr pumping test on a well in the crystalline metamorphic rock the flow was controlled to within 0.1 per cent of the total discharge, which was 0.94 l/s. The water level fluctuations due to earth tides in the pumping well were 10 cm, the same as when this well was not being pumped. (U.S.)

  6. Variscan thrusting in I- and S-type granitic rocks of the Tribeč Mountains, Western Carpathians (Slovakia: evidence from mineral compositions and monazite dating

    Broska Igor

    2015-12-01

    Full Text Available The Tribeč granitic core (Tatric Superunit, Western Carpathians, Slovakia is formed by Devonian/Lower Carboniferous, calc-alkaline I- and S-type granitic rocks and their altered equivalents, which provide a rare opportunity to study the Variscan magmatic, post-magmatic and tectonic evolution. The calculated P-T-X path of I-type granitic rocks, based on Fe-Ti oxides, hornblende, titanite and mica-bearing equilibria, illustrates changes in redox evolution. There is a transition from magmatic stage at T ca. 800–850 °C and moderate oxygen fugacity (FMQ buffer to an oxidation event at 600 °C between HM and NNO up to the oxidation peak at 480 °C and HM buffer, to the final reduction at ca. 470 °C at ΔNN= 3.3. Thus, the post-magmatic Variscan history recorded in I-type tonalites shows at early stage pronounced oxidation and low temperature shift back to reduction. The S-type granites originated at temperature 700–750 °C at lower water activity and temperature. The P-T conditions of mineral reactions in altered granitoids at Variscan time (both I and S-types correspond to greenschist facies involving formation of secondary biotite. The Tribeč granite pluton recently shows horizontal and vertical zoning: from the west side toward the east S-type granodiorites replace I-type tonalites and these medium/coarse-grained granitoids are vertically overlain by their altered equivalents in greenschist facies. Along the Tribeč mountain ridge, younger undeformed leucocratic granite dykes in age 342±4.4 Ma cut these metasomatically altered granitic rocks and thus post-date the alteration process. The overlaying sheet of the altered granites is in a low-angle superposition on undeformed granitoids and forms “a granite duplex” within Alpine Tatric Superunit, which resulted from a syn-collisional Variscan thrusting event and melt formation ~340 Ma. The process of alteration may have been responsible for shifting the oxidation trend to the observed

  7. Climax Granite, Nevada Test Site, as a host for a rock mechanics test facility related to the geologic disposal of high level nuclear wastes

    Heuze, F.E.

    1981-02-01

    This document discusses the potential of the Climax pluton, at the Nevada Test Site, as the host for a granite mechanics test facility related to the geologic disposal of high-level nuclear waste. The Climax granitic pluton has been the site of three nuclear weapons effects tests: Hard Hat, Tiny Tot, and Piledriver. Geologic exploration and mapping of the granite body were performed at the occasion of these tests. Currently, it is the site Spent Fuel Test (SFT-C) conducted in the vicinity of and at the same depth as that of the Piledriver drifts. Significant exploration, mapping, and rock mechanics work have been performed and continue at this Piledriver level - the 1400 (ft) level - in the context of SFT-C. Based on our technical discussions, and on the review of the significant geological and rock mechanics work already achieved in the Climax pluton, based also on the ongoing work and the existing access and support, it is concluded that the Climax site offers great opportunities for a rock mechanics test facility. It is not claimed, however, that Climax is the only possible site or the best possible site, since no case has been made for another granite test facility in the United States. 12 figures, 3 tables

  8. Data and uncertainty assessment for radionuclide Kd partitioning coefficients in granitic rock for use in SR-Can calculations

    Crawford, James; Neretnieks, Ivars; Malmstroem, Maria

    2006-10-01

    SKB is currently preparing licence applications related to the proposed deep repository for spent nuclear fuel as well as the encapsulation plant required for canister fabrication. The present report is one of several specific data reports that form the data input to an interim safety report (SR-Can) for the encapsulation plant licence application. This report concerns the derivation and recommendation of generic K d data (i.e. linear partitioning coefficients) for safety assessment modelling of far-field radionuclide transport in fractured granitic rock. The data are derived for typical Swedish groundwater conditions and rock types distinctive of those found on the Simpevarp peninsula and Forsmark. Data have been derived for 8 main elements (Cs, Sr, Ra, Ni, Th, U, Np, Am) and various oxidation states. The data have also been supplied with tentative correction factors to account for artefacts that have not been previously considered in detail in previous compilations. For the main reviewed solutes the data are given in terms of a best estimate K d value assumed to be the median of the aggregate set of selected data. A range corresponding to the 25-75% inter-quartile range is also specified and probable ranges of uncertainty are estimated in the form of an upper and lower limit to the expected variability. Data for an additional 19 elements that have not been reviewed are taken from a previous compilation by Carbol and Engkvist

  9. Rapakivi granites and other postorogenic rocks in Finland: their age and the lead isotopic composition of certain associated galena mineralizations

    Vaasjoki, Matti

    1977-01-01

    The ages of the postorogenic rocks of southern Finland have been investigated by utilizing the U-Pb method on zircons. There exists one group of postorgenic intrusions in the Aaland Islands with ages ranging from 1840 to 1800 Ma. The rapakivi granites are younger, the Wiborg massif being 1700-1650, the Aaland massif 1670, the Vehmaa massif 1590 and the Laitila massif 1570 Ma old. In the cases of the Wiborg, Aaland and Laitila massives, younger intrusive phases of 1640 Ma, 1620 Ma and 1540 Ma, respectively, have been met with. The porphyry dikes are in every case of the same age as the main parts of the massifs. Anorthosites spatially associated with the Laitila and Wiborg massifs register a temporal relationship as well. Within the Wiborg massif there seem to have occurred three major magmatic phases: at 1700-1660 Ma, at 1650 Ma and at 1640 Ma. The results of the U-Pb determinations suggest that zircons formed from residual magmatic solutions are liable to produce unusually discordant age patterns. This property is attributed to an abnormally high initial lead content, which may have resulted in an initial distortion of the zircon lattice. The Pb-Pb determinations made from galena occurrences in the rapakivi massifs suggest that they are generated by their host rock. The results also suggest that the radiogeneity of the leads contained in the vein deposits increases as the temperature and the pressure prevailing during ore formation decrease. (author)

  10. Geology and Geochemistry of some crystalline basement rocks in ilesha area, southwestern nigeria: implications on provenance and evolution

    Oyinloye, A.O.

    2007-01-01

    Geological and geochemical study of the basement complex rocks in ilesha schist belt revealed that amphibolite, hornblende gneiss and granite gneiss are the major constituents. The gneisses are composed of similar rock forming silicates with variations in abundance. The amphibolite being a mafic rock has different compositions, containing abundant pyroxene, actinolite and tremolite. Monazite is present in the mineralogy of all these rocks. Chemical composition of these rocks revealed that they are petrogenetically related. Geochemical diagrams, plotted from chemical composition of these rocks, REE fractionation trends and presence of monazite in their mineralogy reveal that all these rocks were derived from a mixed magma source which did not originate from a pure tipper mantle, but possibly from a back arc tectonic setting. The pattern of the REE, progressively increasing negative Eu/Eu anomaly, La/sub N//Yb/sub N/ from the amphibolite to the granite gneiss and marked Eu depletion tend to implicate evolution through fractionation of a mixed basaltic magma to form the precursor of these rocks. The amphibolite probably represents the sample of the original basaltic magma. (author)

  11. Final workshop proceedings of the collaborative project ''Crystalline ROCK retention processes''

    Rabung, Thomas; Garcia, David; Montoya Vanessa; Molinero, Jorge (eds.)

    2014-07-01

    The present document is the proceedings of the Final Workshop of the EURATOM FP7 Collaborative Project CROCK (Crystalline Rock Retention Processes). The key driver for initiation the CP CROCK, identified by national Waste Management Organizations, is the undesired high uncertainty and the associated conservatism with respect to the radionuclide transport in the crystalline host-rock far-field around geological disposal of high-level radioactive wastes.

  12. Geochronology, geochemistry, and petrogenesis of late Permian to early Triassic mafic rocks from Darongshan, South China: Implications for ultrahigh-temperature metamorphism and S-type granite generation

    Xu, Wang-Chun; Luo, Bi-Ji; Xu, Ya-Jun; Wang, Lei; Chen, Qi

    2018-05-01

    The role of the mantle in generating ultrahigh-temperature metamorphism and peraluminous S-type granites, and the extent of crust-mantle interaction are topics fundamental to our understanding of the Earth's evolution. In this study we present geochronological, geochemical, and Sr-Nd-Hf isotopic data for dolerites and mafic volcanic rocks from the Darongshan granite complex belt in western Cathaysia, South China. LA-ICP-MS U-Pb zircon analyses yielded magma crystallization ages of ca. 250-248 Ma for the dolerites, which are coeval with eruption of the mafic volcanic rocks, ultrahigh-temperature metamorphism, and emplacement of S-type granites in the Darongshan granite complex belt. The mafic volcanic rocks are high-K calc-alkaline or shoshonitic, enriched in Th, U, and light rare earth elements, and depleted in Nb, Ta and Ti. The dolerites are characterized by high Fe2O3tot (11.61-20.39 wt%) and TiO2 (1.62-3.17 wt%), and low MgO (1.73-4.38 wt%), Cr (2.8-10.8 ppm) and Ni (2.5-11.4 ppm). Isotopically, the mafic volcanic rocks have negative whole-rock εNd(t) values (-6.7 to -9.0) and high ISr values (0.71232 to 0.71767), which are slightly depleted compared with the dolerite samples (εNd(t) = -10.3 to -10.4 and ISr = 0.71796 to 0.71923). Zircons in the dolerites have εHf(t) values of -7.6 to -10.9. The mafic volcanic rocks are interpreted to have resulted from the partial melting of an enriched lithospheric mantle source with minor crustal contamination during ascent, whereas the dolerites formed by late-stage crystallization of enriched lithospheric mantle-derived magmas after fractionation of olivine and pyroxene. The formation of these mantle-derived mafic rocks may be attributed to transtension along a NE-trending strike-slip fault zone that was related to oblique subduction of the Paleo-Pacific plate beneath South China. Such underplated mafic magmas would provide sufficient heat for the generation of ultrahigh-temperature metamorphism and S-type granites, and

  13. Review of geoscientific data of relevance to disposal of spent nuclear fuel in deep boreholes in crystalline rock

    Marsic, Nico; Grundfelt, Bertil

    2013-09-01

    In this report a compilation of recent geoscientific data of relevance to disposal of spent nuclear fuel in deep boreholes in Sweden is presented. The goal of the study has been limited to identifying and briefly describing such geoscientific information of relevance to disposal in deep boreholes that was not available at the time when previous compilations were made. Hence, the study is not to be regarded as a general up-date of new geoscientific information. Disposal of spent nuclear fuel in deep boreholes has been studied in Sweden since the second half of the 1980s. The currently studied concept has been proposed by Sandia National Laboratories in the USA. In this concept the spent fuel elements are encapsulated in cylindrical steel canisters that are joined together in strings of 40 canisters and lowered into five kilometres deep boreholes. Ten such strings are stacked between three and five kilometres depth separated from each other by concrete plugs. The study started with a review of boreholes that have been reported after the previous reviews that were published in 1998 and 2004. A total of 12 boreholes of potential relevance were identified. Further study showed that only four out of these holes penetrated into crystalline rock. Two of these were deemed to be less relevant because they were drilled in areas with much higher geothermal gradient than in the parts of the Fennoscandian shield that realistically could host a Swedish deep borehole repository. Of the two remaining boreholes, only one, a geoscientific hole drilled at Outokumpu in Finland, is associated with a reasonably complete geoscientific data set. It is worth mentioning that a large part of this hole is drilled through meta sedimentary rock (mica schist) rather than granitic rock. The information collected and reviewed has been gathered under the headings hydraulic conditions, geothermal conditions, hydrogeochemical conditions, bacteriological activity and rock mechanical properties. Only

  14. Review of geoscientific data of relevance to disposal of spent nuclear fuel in deep boreholes in crystalline rock

    Marsic, Nico; Grundfelt, Bertil [Kemakta Konsult AB, Stockholm (Sweden)

    2013-09-15

    In this report a compilation of recent geoscientific data of relevance to disposal of spent nuclear fuel in deep boreholes in Sweden is presented. The goal of the study has been limited to identifying and briefly describing such geoscientific information of relevance to disposal in deep boreholes that was not available at the time when previous compilations were made. Hence, the study is not to be regarded as a general up-date of new geoscientific information. Disposal of spent nuclear fuel in deep boreholes has been studied in Sweden since the second half of the 1980s. The currently studied concept has been proposed by Sandia National Laboratories in the USA. In this concept the spent fuel elements are encapsulated in cylindrical steel canisters that are joined together in strings of 40 canisters and lowered into five kilometres deep boreholes. Ten such strings are stacked between three and five kilometres depth separated from each other by concrete plugs. The study started with a review of boreholes that have been reported after the previous reviews that were published in 1998 and 2004. A total of 12 boreholes of potential relevance were identified. Further study showed that only four out of these holes penetrated into crystalline rock. Two of these were deemed to be less relevant because they were drilled in areas with much higher geothermal gradient than in the parts of the Fennoscandian shield that realistically could host a Swedish deep borehole repository. Of the two remaining boreholes, only one, a geoscientific hole drilled at Outokumpu in Finland, is associated with a reasonably complete geoscientific data set. It is worth mentioning that a large part of this hole is drilled through meta sedimentary rock (mica schist) rather than granitic rock. The information collected and reviewed has been gathered under the headings hydraulic conditions, geothermal conditions, hydrogeochemical conditions, bacteriological activity and rock mechanical properties. Only

  15. Evaluation of technology for large- and small-diameter boreholes to characterize crystalline rock

    1985-05-01

    Testing methods that have been used in large- and small-diameter boreholes (152 and 76 mm [6 and 3 in.]) were evaluated on their ability to characterize crystalline rocks. The methods evaluated included in-hole geomechanical, geophysical, and geohydrologic techniques and associated laboratory core tests; specific emphasis was on techniques that might be used in a field characterization program involving a small number of deep (up to 1500 m [5000 ft]) boreholes. Each technique was evaluated with regard to its effectiveness and limitations, applicability to the acquisition of data for anticipated rock conditions, and adequacy for assessing the required rock/hydrologic characteristics. Many pertinent case histories that helped to assess applicability were reviewed. A principal objective of the evaluations was to assess whether the techniques would be equally useful in both large- and small-diameter boreholes. Of the techniques evaluated, most are suitable for use in both large- and small-diameter boreholes. Borehole logging, hydrologic testing, and core-testing techniques provide suitable results in both borehole diameters. Geomechanical testing techniques provide suitable data in smaller diameter boreholes and have been designed for application at primarily shallow depths. The results of this study will be of use to the Office of Crystalline Repository Development (OCRD) in determining to what degree it is appropriate to use drilling, sampling, and testing techniques in small-diameter boreholes as opposed to large-diameter methods, while at the same time collecting adequate data for characterizing crystalline rock environments for potential use as a high-level radioactive waste repository. Additionally, further developmental work and specific testing techniques are recommended

  16. Time dependency in the mechanical properties of crystalline rocks. A literature survey

    Hagros, A.; Johansson, E.; Hudson, J.A.

    2008-09-01

    Because of the long design life, elevated temperatures, and the location at depth (high stresses), time-dependent aspects of the mechanical properties of crystalline rock are potentially important for the design and the long term safety of the radioactive waste repository at Olkiluoto. However, time-dependent effects in rock mechanics are still one of the least understood aspects of the physical behaviour of rock masses, this being partly due to the fact that it is difficult to conduct long-term experimental tests - either in the laboratory or in situ. Yet, the time-dependent mechanical behaviour needs to be characterised so that it can be included in the modelling studies supporting repository design. The Introduction explains the background to the literature survey and includes definitions of the terms 'creep' (increasing strain at constant stress) and 'stress relaxation' (decreasing stress at constant strain). Moreover, it is noted that the rock around an in situ excavation is loaded by the adjacent rock elements and so the timedependent behaviour will depend on the unloading stiffness of these and hence will not actually be either pure creep or pure stress relaxation. The Appendix contains the results of the literature survey of reported time-dependent research as it applies to crystalline rock. A summary of each of the 38 literature items is presented in tabular form covering document number, subject area, document reference, subject matter, objectives, methodology, highlighted figures, conclusions and comments. It is concluded that the time-dependent failure strength of all rocks observed may be interpreted by sub-critical crack growth assisted by the stress corrosion mechanism. Also, certain parameters are known to affect the long-term properties: mineralogy, grain size, water/water chemistry, confining stress and loading history. At some point in the loading history of rock, the state of crack development reaches a point whereby the continued generation of

  17. Solute transport in crystalline rocks at Aspö--I: geological basis and model calibration.

    Mazurek, Martin; Jakob, Andreas; Bossart, Paul

    2003-03-01

    Water-conducting faults and fractures were studied in the granite-hosted Aspö Hard Rock Laboratory (SE Sweden). On a scale of decametres and larger, steeply dipping faults dominate and contain a variety of different fault rocks (mylonites, cataclasites, fault gouges). On a smaller scale, somewhat less regular fracture patterns were found. Conceptual models of the fault and fracture geometries and of the properties of rock types adjacent to fractures were derived and used as input for the modelling of in situ dipole tracer tests that were conducted in the framework of the Tracer Retention Understanding Experiment (TRUE-1) on a scale of metres. After the identification of all relevant transport and retardation processes, blind predictions of the breakthroughs of conservative to moderately sorbing tracers were calculated and then compared with the experimental data. This paper provides the geological basis and model calibration, while the predictive and inverse modelling work is the topic of the companion paper [J. Contam. Hydrol. 61 (2003) 175]. The TRUE-1 experimental volume is highly fractured and contains the same types of fault rocks and alterations as on the decametric scale. The experimental flow field was modelled on the basis of a 2D-streamtube formalism with an underlying homogeneous and isotropic transmissivity field. Tracer transport was modelled using the dual porosity medium approach, which is linked to the flow model by the flow porosity. Given the substantial pumping rates in the extraction borehole, the transport domain has a maximum width of a few centimetres only. It is concluded that both the uncertainty with regard to the length of individual fractures and the detailed geometry of the network along the flowpath between injection and extraction boreholes are not critical because flow is largely one-dimensional, whether through a single fracture or a network. Process identification and model calibration were based on a single uranine breakthrough

  18. Kinetic approach for interactive reactions of radionuclide, bacteria and granitic crushed rock

    Kim, Jung Woo; Baik, Min Hoon; Lee, Seung Yeop; Lee, Jae Kwang; Kim, Seung Soo; Oh, Jong Min; Lee, Tae Yup

    2011-01-01

    For many radionuclides, sorption is an important phenomenon as their migration rates in groundwater are reduced in both engineered barrier and fractured rock matrix. Sorption of radionuclides is strongly dependent on the chemistry of the surrounding groundwater, such as pH, Eh, ionic strength, etc., by changing their valence states (e.g.,). In addition, it is also known that some bacteria can change the mobility and speciation of a radionuclide in groundwater. Biological immobilization mechanisms of radionuclides include precipitation, transformation to less soluble forms and so on. On the other hand, bacteria can also play a role of sorbent for radionuclides. Since bacteria can not only be mobile as a colloid but also be immobile as biofilm in the rock fracture, the bacteria as the sorbents of radionuclides in the groundwater can have both positive and negative effects on the radionuclide migration. In this study, therefore, sorption of radionuclide onto rock surface in the presence of bacteria was investigated via batch experiments. Although sorption equilibrium state can be expected in the transport of weakly sorbing (distribution coefficient, K d -3 m 3 kg -1 ) or strongly adsorbing (K d > ∼4.6 m 3 kg -1 ) nuclides in fractured rock, sorption kinetics needs to be considered in the intermediate range. Therefore, the sorption of radionuclide whose valence state is expected to be changed by biological reduction was evaluated in a kinetic approach

  19. Experimental thermomechanical damage as first approach to understand the petrophysical behavior of the granitic host-rocks from an active fractured-geothermal system (Liquiñe, Chile - 39º S)

    Molina Piernas, E.; Sepúlveda, J.; Arancibia, G.; Roquer, T.; Morata, D.; Bracke, R.; Vázquez, P.

    2017-12-01

    Chile's location along an active subduction zone has endowed it with a high geothermal potential. However, a better understanding of the thermomechanical and fluid transport properties of rocks is required to assess the potential of geothermal systems and thereby enhance the possibilities for their use. We have focused in the area surrounding Liquiñe, in the Southern Andean Volcanic Zone (Chile, 39º S). This area hosts several recent thermal manifestations, predominantly hot springs, and it is affected by the Liquiñe-Ofqui Fault Zone (LOFZ), which controls the position of the modern volcanic arc in southern Chile and cuts the Patagonian batholith. We have carried out experimental analyzes in order to understand this geothermal system and the influence of the thermomechanical features over the granitic host-rocks (low-porous crystalline rocks). To do this, physical properties such as capillary water absorption coefficient, Vp-wave velocity and compressive resistance were evaluated before and after heating rock samples at 150 ºC and 210 ºC (at ambient pressure) in an oven at a heating rate of 6 °C/min and maintaining the maximum temperature for 4 hours. The cooling rate was less than 2 °C/min to avoid shrinkage phenomena. The results show that the damage by heat was greater at 210 ºC than 150 ºC, likely due to an increased capillary coefficient ( 30% and 25%). On the contrary, Vpvelocity ( -19% and -13%) and compressive resistance ( -27% in both cases) decreased, with respect to unheated samples. Consequently, we can infer an inherent effect on the later fracture process due to the thermal stress when this granitic body was at depth. After that, and considering the local and regional strain-stress state, both factors have facilitated the fluid flow, increasing the permeability of this granitic host-rock allowing the presence of hot-springs. Future work will be to acquire complementary petrophysical parameters, such as porosity, permeability, thermal

  20. Structural geology and geophysics as a support to build a hydrogeologic model of granite rock

    Martinez-Landa, Lurdes; Carrera, Jesús; Pérez-Estaún, Andrés; Gómez, Paloma; Bajos, Carmen

    2016-06-01

    A method developed for low-permeability fractured media was applied to understand the hydrogeology of a mine excavated in a granitic pluton. This method includes (1) identifying the main groundwater-conducting features of the medium, such as the mine, dykes, and large fractures, (2) implementing this factors as discrete elements into a three-dimensional numerical model, and (3) calibrating these factors against hydraulic data . A key question is how to identify preferential flow paths in the first step. Here, we propose a combination of several techniques. Structural geology, together with borehole sampling, geophysics, hydrogeochemistry, and local hydraulic tests aided in locating all structures. Integration of these data yielded a conceptual model of the site. A preliminary calibration of the model was performed against short-term (Model validity was tested by blind prediction of a long-term (4 months) large-scale (1 km) pumping test from the mine, which yielded excellent agreement with the observations. Model results confirmed the sparsely fractured nature of the pluton, which has not been subjected to glacial loading-unloading cycles and whose waters are of Na-HCO3 type.

  1. Monitoring Local Changes in Granite Rock Under Biaxial Test: A Spatiotemporal Imaging Application With Diffuse Waves

    Xie, Fan; Ren, Yaqiong; Zhou, Yongsheng; Larose, Eric; Baillet, Laurent

    2018-03-01

    Diffuse acoustic or seismic waves are highly sensitive to detect changes of mechanical properties in heterogeneous geological materials. In particular, thanks to acoustoelasticity, we can quantify stress changes by tracking acoustic or seismic relative velocity changes in the material at test. In this paper, we report on a small-scale laboratory application of an innovative time-lapse tomography technique named Locadiff to image spatiotemporal mechanical changes on a granite sample under biaxial loading, using diffuse waves at ultrasonic frequencies (300 kHz to 900 kHz). We demonstrate the ability of the method to image reversible stress evolution and deformation process, together with the development of reversible and irreversible localized microdamage in the specimen at an early stage. Using full-field infrared thermography, we visualize stress-induced temperature changes and validate stress images obtained from diffuse ultrasound. We demonstrate that the inversion with a good resolution can be achieved with only a limited number of receivers distributed around a single source, all located at the free surface of the specimen. This small-scale experiment is a proof of concept for frictional earthquake-like failure (e.g., stick-slip) research at laboratory scale as well as large-scale seismic applications, potentially including active fault monitoring.

  2. Understanding large scale groundwater flow in fractured crystalline rocks to aid in repository siting

    Davison, C.; Brown, A.; Gascoyne, M.; Stevenson, D.; Ophori, D.

    2000-01-01

    Atomic Energy of Canada Limited (AECL) conducted a ten-year long groundwater flow study of a 1050 km 2 region of fractured crystalline rock in southeastern Manitoba to illustrate how an understanding of large scale groundwater flow can be used to assist in selecting a hydraulically favourable location for the deep geological disposal of nuclear fuel waste. The study involved extensive field investigations that included the drilling testing, sampling and monitoring of twenty deep boreholes distributed at detailed study areas across the region. The surface and borehole geotechnical investigations were used to construct a conceptual model of the main litho-structural features that controlled groundwater flow through the crystalline rocks of the region. Eighty-three large fracture zones and other spatial domains of moderately fractured and sparsely fractured rocks were represented in a finite element model of the area to simulate regional groundwater flow. The groundwater flow model was calibrated to match the observed groundwater recharge rate and the hydraulic heads measured in the network of deep boreholes. Particle tracking was used to determine the pathways and travel times from different depths in the velocity field of the calibrated groundwater flow model. The results were used to identify locations in the regional flow field that maximize the time it takes for groundwater to travel to surface discharge areas through long, slow groundwater pathways. One of these locations was chosen as a good hypothetical location for situating a nuclear fuel waste disposal vault at 750 m depth. (authors)

  3. Permeability and seismic velocity anisotropy across a ductile-brittle fault zone in crystalline rock

    Wenning, Quinn C.; Madonna, Claudio; de Haller, Antoine; Burg, Jean-Pierre

    2018-05-01

    This study characterizes the elastic and fluid flow properties systematically across a ductile-brittle fault zone in crystalline rock at the Grimsel Test Site underground research laboratory. Anisotropic seismic velocities and permeability measured every 0.1 m in the 0.7 m across the transition zone from the host Grimsel granodiorite to the mylonitic core show that foliation-parallel P- and S-wave velocities systematically increase from the host rock towards the mylonitic core, while permeability is reduced nearest to the mylonitic core. The results suggest that although brittle deformation has persisted in the recent evolution, antecedent ductile fabric continues to control the matrix elastic and fluid flow properties outside the mylonitic core. The juxtaposition of the ductile strain zone next to the brittle zone, which is bounded inside the two mylonitic cores, causes a significant elastic, mechanical, and fluid flow heterogeneity, which has important implications for crustal deformation and fluid flow and for the exploitation and use of geothermal energy and geologic waste storage. The results illustrate how physical characteristics of faults in crystalline rocks change in fault zones during the ductile to brittle transitions.

  4. Some additional observations on inclusions in the granitic rocks of the Sierra Nevada

    Dodge, F.C.W.; Kistler, R.W.

    1990-01-01

    Microgranular quartz diorite and diorite inclusions are widespread in central Sierra Nevada granitoid rocks and are almost exclusively restricted to hornblende-bearing rocks, most commonly felsic tonalites and mafic granodiorites. The Nd-Sm and Rb-Sr systematics indicate that most inclusions were in isotopic equilibrium with enclosing materials at the time of formation. Silica contents of inclusions and granitoids are contiguous, but inclusions generally contain less than, and granitoids more than, 60% SiO2. Ferric oxide and H2O+ trends relative to SiO2 suggests many inclusions formed as concentrations of hydrous mafic minerals. Variation of other major element oxides and trace elements support this inference. Most inclusions represent fragmented crystal accumulations of early-formed, near-liquidus minerals generated from these previously mixed magmas. -from Authors

  5. The uranium behaviour during rock-water interaction in the granites from the Itu complex (Sao Paulo, Brazil): a laboratory study

    Silva, Helen S.B. da; Marques, Leila S.; Kawauchi, Roberto K., E-mail: leila@iag.usp.br, E-mail: keiji@iag.usp.br [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas. Universidade de Sao Paulo (USP), SP (Brazil)

    2011-07-01

    In order to elucidate the mechanisms involved in the process of uranium leaching due to the rock-water interaction in the granitic rocks from Itu Complex (Sao Paulo, Brazil), an experimental arrangement was developed and built. About 2.5kg of crushed rock fragments from Cabreuva and Indaiatuba Intrusions were maintained at room temperature within a glass flask filled with circulating water. The percolating water was removed periodically (from 10 to 30 days) for uranium analysis and then replaced by an equal volume of fresh water. Alpha spectrometry was used to determine the activity concentrations of {sup 234}U and {sup 238}U, and {sup 234}U/{sup 238}U activity ratios, of the waters as well as of the granites. The results for both samples showed that most of the uranium is leached in the first days after the contact between rock and water. The {sup 234}U/{sup 238}U activity ratios were significantly greater than unity, indicating radioactive disequilibrium between those isotopes, probably due to alpha recoil. Although the uranium activity concentrations in the water samples diminished with the increasing of time, it was not observed considerable variations of the {sup 234}U/{sup 238}U activity ratios. It was also noticed that, the amount of leached uranium as well as the {sup 234}U/{sup 238}U activity ratios are characteristics of each sample submitted to leaching, reflecting the differences of the granite facies mineralogy.(author)

  6. Matrix diffusion of simple cations, anions, and neutral species in fractured crystalline rocks

    Sato, Haruo

    1999-01-01

    The diffusion of radionuclides into the pore spaces of a rock matrix and the pore properties in fractured crystalline rocks were studied. The work concentrated on the predominant water-conducting fracture system in the host granodiorite of the Kamaishi In Situ Test Site, which consists of fracture fillings and altered grandodiorite. Through-diffusion experiments to obtain effective and apparent diffusion coefficients (De and Da, respectively) for Na + , Cs + , HTO, Cl - , and SeO 3 2- as a function of ionic charge were conducted through the fracture fillings and altered and intact granodiorite. The total porosity φ, density, pore-size distribution, and specific surface area of the pores of the rocks were also determined by a water saturation method and Hg porosimetry. The average φ is, in the order from highest to lowest, as follows: fracture fillings (5.6%) greater than altered granodiorite (3.2%) greater than intact granodiorite (2.3%), and gradually it decreases into the matrix. The pore sizes of the intact and altered granodiorite range from 10 nm to 200 microm, and the fracture fillings from 50 nm to 200 microm, but almost all pores are found around 0.1 and 200 microm in the fracture fillings. The De values for all species are in the following order: fracture fillings greater than altered granodiorite greater than intact granodiorite, as with the rock porosity. In addition. no effect of ionic charge on De is found. No significant dependence for Da values on the rock porosity is found. The formation factors FF and geometric factors G of the rocks were evaluated by normalizing the free water diffusion coefficient Do for each species. The FF decreased with decreasing rock porosity, and an empirical equation for the rock porosity was derived to be FF = φ 1.57±0.02 . The G values showed a tendency to slightly decrease with decreasing rock porosity, but they were approximately constant (0.12 to 0.19) in this porosity range. This indicates that accessible pores

  7. Influence of porosity and groundmass crystallinity on dome rock strength: a case study from Mt. Taranaki, New Zealand

    Zorn, Edgar U.; Rowe, Michael C.; Cronin, Shane J.; Ryan, Amy G.; Kennedy, Lori A.; Russell, James K.

    2018-04-01

    Lava domes pose a significant hazard to infrastructure, human lives and the environment when they collapse. Their stability is partly dictated by internal mechanical properties. Here, we present a detailed investigation into the lithology and composition of a Rocks with variable porosity and groundmass crystallinity were compared using measured compressive and tensile strength, derived from deformation experiments performed at room temperature and low (3 MPa) confining pressures. Based on data obtained, porosity exerts the main control on rock strength and mode of failure. High porosity (> 23%) rocks show low rock strength (rocks (5-23%) exhibit higher measured rock strengths (up to 278 MPa) and brittle failure. Groundmass crystallinity, porosity and rock strength are intercorrelated. High groundmass crystal content is inversely related to low porosity, implying crystallisation and degassing of a slowly undercooled magma that experienced rheological stiffening under high pressures deeper within the conduit. This is linked to a slow magma ascent rate and results in a lava dome with higher rock strength. Samples with low groundmass crystallinity are associated with higher porosity and lower rock strength, and represent magma that ascended more rapidly, with faster undercooling, and solidification in the upper conduit at low pressures. Our experimental results show that the inherent strength of rocks within a growing dome may vary considerably depending on ascent/emplacement rates, thus significantly affecting dome stability and collapse hazards.

  8. Study of the possibilities of radioactive waste storage in crystalline formations. Investigation by deep drilling of the Auriat granite

    1982-01-01

    Various and complex scientific problems are raised in many areas by the disposal of radioactive waste in geological formations. Research works are therefore numerous, and are carried out in four basic areas: - improvement of the knowledge of geological media; - characterization of their behaviour vis a vis radioactive waste; - design of deep repositories; - long-term safety assessment of the selected disposal strategies. Aim of the present research is to develop a methodology for investigating granite formations at great depth, in order to characterize their internal structure, and to acquire data about the various physical properties of granite. This research therefore covers the first basic aspect. These goals were obtained by continuous core-drilling of two vertical boreholes at 10m pitch. The main borehole was drilled down to 1003.15m deep, the second one was stopped at 504.40m deep

  9. Excavation and drilling at a spent-fuel test facility in granitic rock

    Patrick, W.C.; Mayr, M.C.

    1981-10-01

    Funding for a project to test the feasibility of safe and reliable storage and retrieval of spent fuel from a commercial nuclear reactor was approved by the Department of Energy on June 2, 1978. By May 28, 1980, 11 spent-fuel assemblies had been emplaced 420 m below the surface in the Climax granitic stock at the Nevada Test Site. Design and construction of the Spent Fuel Test-Climax, including fuel emplacement, had taken less than two years, at a total cost of $18.4 million. Construction activities were preceded by geologic exploration using four cored holes and existing underground workings. The sinking of a 0.76-m-diam shaft to the 420-m level initiated construction at the site. Effective rates of sinking varied from 0.16 m/h with a rotary tricone drill to 0.5 m/h with a hammer drill. Underground excavation included a central canister-storage drift 4.6 x 6.1 x 64 m long, two parallel 3.4 x 3.4-m heater drifts, and a tail drift. About 6700 m{sup 3} were excavated at an average rate of 2 m{sup 3}/h, and 178 cored holes, with diameters from 38 to 152 mm, were drilled. A total length of nearly 1100 m was drilled at rates ranging from 0.4 m/h to 1 m/h, depending on hole size and drilling equipment. Eighteen 610-mm-diam canister emplacement holes were hammer-drilled at an average rate of 1.4 m/h. The use of the critical path method, integrated contractors, and close cooperation between project participants facilitated completion of the project on schedule.

  10. Excavation and drilling at a spent-fuel test facility in granitic rock

    Patrick, W.C.; Mayr, M.C.

    1981-10-01

    Funding for a project to test the feasibility of safe and reliable storage and retrieval of spent fuel from a commercial nuclear reactor was approved by the Department of Energy on June 2, 1978. By May 28, 1980, 11 spent-fuel assemblies had been emplaced 420 m below the surface in the Climax granitic stock at the Nevada Test Site. Design and construction of the Spent Fuel Test-Climax, including fuel emplacement, had taken less than two years, at a total cost of $18.4 million. Construction activities were preceded by geologic exploration using four cored holes and existing underground workings. The sinking of a 0.76-m-diam shaft to the 420-m level initiated construction at the site. Effective rates of sinking varied from 0.16 m/h with a rotary tricone drill to 0.5 m/h with a hammer drill. Underground excavation included a central canister-storage drift 4.6 x 6.1 x 64 m long, two parallel 3.4 x 3.4-m heater drifts, and a tail drift. About 6700 m 3 were excavated at an average rate of 2 m 3 /h, and 178 cored holes, with diameters from 38 to 152 mm, were drilled. A total length of nearly 1100 m was drilled at rates ranging from 0.4 m/h to 1 m/h, depending on hole size and drilling equipment. Eighteen 610-mm-diam canister emplacement holes were hammer-drilled at an average rate of 1.4 m/h. The use of the critical path method, integrated contractors, and close cooperation between project participants facilitated completion of the project on schedule

  11. The hydrocarbon accumulations mapping in crystalline rocks by mobile geophysical methods

    Nesterenko, A.

    2013-05-01

    Sedimentary-migration origin theory of hydrocarbons dominates nowadays. However, a significant amount of hydrocarbon deposits were discovered in the crystalline rocks, which corroborates the theory of non-organic origin of hydrocarbons. During the solving of problems of oil and gas exploration in crystalline rocks and arrays so-called "direct" methods can be used. These methods include geoelectric methods of forming short-pulsed electromagnetic field (FSPEF) and vertical electric-resonance sounding (VERS) (FSPEF-VERS express-technology). Use of remote Earth sounding (RES) methods is also actual. These mobile technologies are extensively used during the exploration of hydrocarbon accumulations in crystalline rocks, including those within the Ukrainian crystalline shield. The results of explorations Four anomalous geoelectric zones of "gas condensate reservoir" type were quickly revealed as a result of reconnaissance prospecting works (Fig. 1). DTA "Obukhovychi". Anomaly was traced over a distance of 4 km. Approximate area is 12.0 km2. DTA"Korolevskaya". Preliminary established size of anomalous zone is 10.0 km2. The anomalous polarized layers of gas and gas-condensate type were determined. DTA "Olizarovskaya". Approximate size of anomaly is about 56.0 km2. This anomaly is the largest and the most intense. DTA "Druzhba". Preliminary estimated size of anomaly is 16.0 km2. Conclusions Long experience of a successful application of non-classical geoelectric methods for the solving of variety of practical tasks allow one to state their contribution to the development of a new paradigm of geophysical researches. Simultaneous usage of the remote sensing data processing and interpretation method and FSPEF and VERS technologies can essentially optimize and speed up geophysical work. References 1. S.P. Levashov. Detection and mapping of anomalies of "hydrocarbon deposit" type in the fault zones of crystalline arrays by geoelectric methods. / S.P. Levashov, N.A. Yakymchuk, I

  12. Modelling small scale infiltration experiments into bore cores of crystalline rock and break-through curves

    Hadermann, J.; Jakob, A.

    1987-04-01

    Uranium infiltration experiments for small samples of crystalline rock have been used to model radionuclide transport. The theory, taking into account advection and dispersion in water conducting zones, matrix diffusion out of these, and sorption, contains four independent parameters. It turns out, that the physical variables extracted from those of the best-fit parameters are consistent with values from literature and independent measurements. Moreover, the model results seem to differentiate between various geometries for the water conducting zones. Alpha-autoradiographies corroborate this result. A sensitivity analysis allows for a judgement on parameter dependences. Finally some proposals for further experiments are made. (author)

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

    Hagros, A.

    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 the repository and the constructability in the rock mass. The system is specific to the KBS-3V disposal concept and can be used only at sites that have been evaluated to be suitable at the site scale. By using the HRC-system, it is possible to identify potentially suitable volumes within the site at several different scales (repository, tunnel and canister scales). The selection of the classification parameters to be included in the HRC-system is based on an extensive study on the rock mass properties and their various influences on the long-term safety, the constructability and the layout and location of the repository. The parameters proposed for the classification at the repository scale include fracture zones, strength/stress ratio, hydraulic conductivity and the Groundwater Chemistry Index. The parameters proposed for the classification at the tunnel scale include hydraulic conductivity, Q' and fracture zones and the parameters proposed for the classification at the canister scale include hydraulic conductivity, Q', fracture zones, fracture width (aperture + filling) and fracture trace length. The parameter values will be used to determine the suitability classes for the volumes of rock to be classified. The HRC-system includes four suitability classes at the repository and tunnel scales and three suitability classes at the canister scale and the classification process is linked to several important decisions regarding the location and acceptability of many components of

  14. Radioactive waste storage in mined caverns in crystalline rock: results of field investigations at Stripa, Sweden

    Witherspoon, P.A.

    1980-10-01

    It is generally agreed that the most practicable method of isolating nuclear wastes from the biosphere is by deep burial in suitable geologic formations. Such burial achieves a high degree of physical isolation but raises questions concerning the rate at which some of these wastes may return to the biosphere through transport by groundwater. Any suitable repository site will be disturbed first by excavation and second by the thermal pulse caused by the radioactive decay of the wastes. To assess the effectiveness of geologic isolation it is necessary to develop the capability of predicting the response of a rock mass to such a thermal pulse. Ultimately, this requires field measurements below the surface in media representative of those likely to be encountered at an actual repository. Access to a granitic rock mass adjacent to a defunct iron ore mine at Stripa, Sweden, at a depth of about 350 m below surface has provided a unique opportunity to conduct a comprehensive suite of hydrological and thermo-mechanical experiments under such conditions. The results of these field tests have shown the importance of geologic structure and the functional dependence of the thermo-mechanical properties on temperature in developing a valid predictive model. The results have also demonstrated the vital importance of carrying out large-scale investigations in a field test facility

  15. Fluid geochemistry associated associated to rocks: preliminary tests om minerals of granite rocks potentially hostess of radioactive waste repository

    Amorim, Lucas E.D.; Rios, Francisco J.; Oliveira, Lucilia A.R. de; Alves, James V.; Fuzikawa, Kazuo; Garcia, Luiz; Ribeiro, Yuri; Matos, Evandro C. de

    2009-01-01

    Fluid inclusions (FI) are micro cavities present on crystals and imprison the mineralizer fluids, and are formed during or posterior to the mineral formation. Those kind of studies are very important for orientation of the engineer barrier projects for this purpose, in order to avoid that the solutions present in the mineral FI can affect the repository walls. This work proposes the development of FI micro compositional studies in the the hostess minerals viewing the contribution for a better understanding of the solution composition present in the metamorphosis granitoid rocks. So, micro thermometric, microchemical and characterization of the material confined in the FI, and the hostess minerals. Great part of the found FI are present in the quartz and plagioclase crystals. The obtained data on the mineral compositions and their inclusions will allow to formulate hypothesis on the process which could occurs at the repository walls, decurrens from of the corrosive character (or not) of the fluids present in the FI, and propose measurements to avoid them

  16. Natural organics in groundwaters and their potential effect on contaminant transport in granitic rock

    Vilks, P.; Bachinski, D.B.; Richer, D.

    1996-07-01

    Naturally occurring organics in groundwaters of the Whiteshell Research Area (WRA) of southern Manitoba and of the Atikokan Research Area of northwestern Ontario were investigated to assess their potential role in radionuclide transport within granite fractures of the Canadian Shield. A survey of dissolved organic carbon (DOC) concentrations, carried out to determine the variability in the organic content of these groundwaters, showed average concentrations in WRA deep groundwaters of 0.8 ± 0.1 mg/L for Fracture Zone 2, 0.8 ± 0.4 mg/L for near-vertical fractures, and 2.3 ± 0.8 mg/L for deeper saline groundwater. Surface waters and near-surface groundwaters had significantly higher DOC with 29.2 ± 0.6 mg/L in streams from the East Swamp. The DOC consisted mainly of hydrophilic neutral compounds 60 to 75%, and hydrophobic and hydrophilic acids 23 to 39%, along with very small amounts of hydrophobic bases and neutrals, and hydrophilic bases. The average complexing capacity of natural organics in WRA deep groundwaters was calculated to be 6.7 x 10 -6 eq/L. The ability of these organics to complex radionuclides was tested using conditional stability constants from the literature for humic complex formation with trivalent, tetravalent, pentavalent and hexavalent actinides. The chemistries of Np(V) and U(VI) were predicted to be dominated by inorganic complexes and not significantly affected by organics. Accurate predictions for AM(III) and Th(IV) could not be made since the literature contains a wide range in values of stability constants for humic complexes with these elements. Surface waters and near-surface groundwaters in many areas of the Canadian Shield contain enough humics to complex a significant fraction of dissolved actinides. Radiocarbon ages of humics from WRA groundwater varied between 3600 and 6200 years before present, indicating that a component of humic substances in deep groundwaters must originate from near-surface waters. 54 refs., 15 tabs., 5

  17. Deposition behavior of polystyrene latex particles on solid surfaces during migration through an artificial fracture in a granite rock sample

    Chinju, Hirofumi; Tanaka, Satoru; Kuno, Yoshio

    2001-01-01

    The deposition behavior of colloids during transport through heterogeneous media was observed by conducting column experiments to study migration of polystyrene latex particles (diameter=309 nm) through columns packed with artificially fractured granite rock (length=300 and 150 mm). The experiments were conducted under conditions of different ionic strengths and flow rates. The results were similar to those for colloid deposition in columns packed with glass beads reported previously; the colloid breakthrough curves showed three stages, characterized by different rates of change in the concentration of effluent. Colloid deposition on the fracture surfaces was described by considering strong and weak deposition sites. Scanning Electron Microscopy (SEM) observations indicated the existence of strong and weak sites on the fracture surfaces regardless of mineral composition. The observations also showed that the strong deposition sites tended to exist on surface irregularities such as cracks or protrusions. The degree of colloid deposition increased with increasing ionic strength and decreasing flow rate. The dependencies on ionic strength and flow rate agreed qualitatively with the DLVO theory and the previous experimental results, respectively. (author)

  18. Developing a Fracture Model of the Granite Rocks Around the Research Tunnel at the Mizunami Underground Research Laboratory in Central Japan

    Kalinina, E.; Hadgu, T.; Wang, Y.

    2017-12-01

    The Mizunami Underground Research Laboratory (MIU) is located in Tono area in Central Japan. It is operated by the Japan Atomic Energy Agency (JAEA) with the main purpose of providing scientific basis for the research and development of technologies needed for deep geological disposal of radioactive waste in fractured crystalline rocks. The current work is focused on the research and experiments in the tunnel located at 500 m depth. The data collected in the tunnel and exploratory boreholes were shared with the participants of the DEvelopment of COupled models and their VALidation against EXperiments (DECOVALEX), an international research and model comparison collaboration. This study describes the development of the fracture model representing granite rocks around the research tunnel. The model domain is 100x150x100m with the main experimental part of the tunnel, Closure Test Drift, located approximately in the center. The major input data were the fracture traces measured on the tunnel walls (total of 2,023 fractures), fractures observed in the horizontal borehole parallel to the tunnel, and the packer tests conducted in this borehole and one vertical borehole located within the modeling domain. 78 fractures (the ones with the inflow) in the tunnel were incorporated in the development of the fracture model. Fracture size was derived from the fracture trace analysis. It was shown that the fracture radius followed lognormal distributions. Fracture transmissivity was estimated from an analytical solution of inflow into the tunnel through an individual fracture and the total measured inflow into the tunnel. 16 fractures were incorporated in the model along the horizontal borehole. The packer test data in the different well intervals were used to estimate the range in fracture transmissivity. A relationship between the fracture transmissivity and fracture radius was developed. The fractures in the tunnel and borehole were used to derive fracture orientation and

  19. Protocol proposal for radon concentration mensuration from granitic rocks in marble factory; Proposta de protocolo para medicao de concentracoes de radonio proveniente de rochas graniticas em marmorarias

    Del Claro, Flavia

    2016-11-01

    Naturally occurring radionuclides such as radon ({sup 222}Rn), its decay products and other elements from the radioactive series of uranium ({sup 238}U and {sup 235}U) and thorium ({sup 232}Th) are an important source of human exposure to natural radioactivity. The worldwide evaluation of health radiobiological effects and risks from population exposure to natural radionuclides is a growing concern. Radionuclides such as radon ({sup 222}Rn), the thoron ({sup 220}Rn), radio ({sup 2}'2'6Ra), thorium ({sup 23}'2Th) and potassium ({sup 40}K) may occur in materials commonly used in construction of dwellings and buildings. Thus, the radioactivity from marbles and granites is of importance, so that under certain conditions these materials radioactivity levels can be hazardous requiring the implementation of mitigation measurements. This research presents a technical protocol marble factories for the control human exposure to natural radioactivity exhaled from granitic rocks. The protocol was based on measurements of the {sup 222}Rn and {sup 220}Rn concentration in Brazilian granite rocks commonly nationally and exported. The {sup 222}Rn and {sup 220}Rn measurements were done using the AlphaGUARD (Saphymo GmbH) and RAD7 (Durridge Company) apparatus, respectively. The samples of granite were sealed in glass jars for 40 days in to achieve secular equilibrium between {sup 226}Ra and {sup 222}Rn radionuclides. The measurements were performed on Applied Nuclear Physics Laboratory at the Federal Technological University of Parana. Also, solid-state nuclear track detectors CR-39 were installed in a marble factory environments located in Curitiba - Parana for the evaluation of {sup 222}Rn concentrations in workplaces. The CR-39 detectors were exposed for about 90 days and submitted to etching process. The alpha particle tracks were observed using an optical microscope. Some granite samples analyzed presented {sup 222}Rn concentrations of attention, since the average

  20. The ongoing search for the oldest rock on the Danish island of Bornholm: new U-Pb zircon ages for a quartz-rich xenolith and country rock from the Svaneke Granite

    Waight, Tod Earle; Serre, Simon H.; Næsby, Sebastian H.

    2017-01-01

    Previous geochronological studies on the Danish island of Bornholm have not identified any rocks older than c. 1.46 Ga. New LA-ICP-MS U-Pb zircon ages are presented for a xenolith within, and the country rock gneiss adjacent to, the Svaneke Granite on Bornholm. The xenolith is fine......-grained and quartz-rich and was likely derived from either a quartz-rich sedimentary protolith or a hydrothermally altered felsic volcanic rock. The relatively fine-grained felsic nature of the country rock gneiss and the presence of large zoned feldspars that may represent phenocrysts suggest its protolith may have...... been a felsic volcanic or shallow intrusive rock. A skarn-like inclusion from a nearby locality likely represents an originally carbonate sediment and is consistent with supracrustal rocks being present at least locally. Zircon data from the xenolith define an upper intercept age of 1483 ± 12 Ma (2σ...

  1. The origin, source and cycling of methane in deep crystalline rock biosphere

    Riikka eKietäväinen

    2015-07-01

    Full Text Available The emerging interest in using stable bedrock formations for industrial purposes, e.g. nuclear waste disposal, has increased the need for understanding microbiological and geochemical processes in deep crystalline rock environments, including the carbon cycle. Considering the origin and evolution of life on Earth, these environments may also serve as windows to the past. Various geological, chemical and biological processes can influence the deep carbon cycle. Conditions of CH4 formation, available substrates and time scales can be drastically different from surface environments. This paper reviews the origin, source and cycling of methane in deep terrestrial crystalline bedrock with an emphasis on microbiology. In addition to potential formation pathways of CH4, microbial consumption of CH4 is also discussed. Recent studies on the origin of CH4 in continental bedrock environments have shown that the traditional separation of biotic and abiotic CH4 by the isotopic composition can be misleading in substrate-limited environments, such as the deep crystalline bedrock. Despite of similarities between Precambrian continental sites in Fennoscandia, South Africa and North America, where deep methane cycling has been studied, common physicochemical properties which could explain the variation in the amount of CH4 and presence or absence of CH4 cycling microbes were not found. However, based on their preferred carbon metabolism, methanogenic microbes appeared to have similar spatial distribution among the different sites.

  2. The origin, source, and cycling of methane in deep crystalline rock biosphere.

    Kietäväinen, Riikka; Purkamo, Lotta

    2015-01-01

    The emerging interest in using stable bedrock formations for industrial purposes, e.g., nuclear waste disposal, has increased the need for understanding microbiological and geochemical processes in deep crystalline rock environments, including the carbon cycle. Considering the origin and evolution of life on Earth, these environments may also serve as windows to the past. Various geological, chemical, and biological processes can influence the deep carbon cycle. Conditions of CH4 formation, available substrates and time scales can be drastically different from surface environments. This paper reviews the origin, source, and cycling of methane in deep terrestrial crystalline bedrock with an emphasis on microbiology. In addition to potential formation pathways of CH4, microbial consumption of CH4 is also discussed. Recent studies on the origin of CH4 in continental bedrock environments have shown that the traditional separation of biotic and abiotic CH4 by the isotopic composition can be misleading in substrate-limited environments, such as the deep crystalline bedrock. Despite of similarities between Precambrian continental sites in Fennoscandia, South Africa and North America, where deep methane cycling has been studied, common physicochemical properties which could explain the variation in the amount of CH4 and presence or absence of CH4 cycling microbes were not found. However, based on their preferred carbon metabolism, methanogenic microbes appeared to have similar spatial distribution among the different sites.

  3. Programme of research into the management and storage of radioactive waste. Aqueous phase transport through granitic rocks

    Bradbury, M.H.; Green, A.

    1984-01-01

    Three aspects of work on aqueous phase transport by diffusion through porous granites are considered (1) The formation factor and long range connectivity of pore structure. (2) The effect of degraded fissure surfaces on diffusion into the main pore structure. (3) Effect of overburden pressures at depth on diffusion rates. Experiments were conducted on Cornish carnmenellis granite. (U.K.)

  4. Evaluation of color and radon exhalation rate in granite rocks between accelerated aging cycles

    Silva, Francisco Diones Oliveira

    2016-01-01

    Data used for the assessment of the analyzes performed on three types of dimension stone (Juparana Bordeaux, Branco Nevasca and Golden Artico), in natural state and after several cycles of accelerated aging are presented, correlating them with the gas exhalation rate radon issued by the analyzed lithologies. In the samples were conducted permeability, porosity, colorimetry, image analysis, petrographic and exhalation rate of radon, accompanied by aging tests on climate simulation chamber which simulates change situations of materials by weathering agents, accelerating wear and tear samples. The measurements were performed on samples in natural state, with 50 and 100 cycles of aging acceleration, where each cycle corresponds to variations in temperature and humidity in climatic simulation chamber, with the addition of an internal atmosphere of SO_2 with 25 concentration ppm. The results obtained during the tests were related to better analysis of the changes observed on the samples and the variation rate of exhalation radon emitted. The rocks have radon concentration values above the limits suggested by relevant international agencies (200-400 Bq/m³), with average values in the natural state, in 6149, 1619 and 866 Bq/m³ for Juparana Bordeaux, Branco Nevasca and Golden Arctic, respectively. The other aging cycles (50 and 100 cycles) showed an average increase of 0.8% for Juparana Bordeaux, 6.9% for White Blizzard and -23.87% for the Golden Arctic, with 50 cycles. From 50 to 100 cycles, there was reduction of 3.43% for Juparana Bordeaux and 22.15% for Branco Nevasca and an increase of 13.82% in the Golden Artico. The porosity results in the natural state obtained values an average of 0.696% for Juparana Bordeaux, 0.919% for Branco Nevasca and 0.830% for Golden Artico, and after 50 cycles of accelerated aging, obtained 0.621% to Juparana Bordeaux, 0.910% for Branco Nevasca and 0.840% for Golden Artico. The permeability of the samples showed values in the natural

  5. Age and isotopic fingerprints of some plutonic rocks in the Wiborg rapakivi granite batholith with special reference to the dark wiborgite of the Ristisaari Island

    Rämö, O.T.

    2014-12-01

    Full Text Available The mid-Proterozoic, locus classicus Wiborg rapakivi granite batholith of southeastern Finland and adjacent Russia comprises a varying, bimodal (silicic-basic sequence of plutonic, subvolcanic, and volcanic rocks. At the current level of erosion silicic rocks are dominant, the most prominent of which are wiborgites and dark wiborgites (that have been considered to mark the main build-up stage of the batholith and pyterlites. New observations and optical microscopy data from the dark wiborgite-dominated Ristisaari Island in the southern, off-shore part of the Wiborg batholith show that dark plagioclase megacrysts in dark wiborgite are calcic xenocrysts. They were probably incorporated into wiborgite magma from consanguineous massiftype anorthosite magmas in the course of the evolution of the bimodal magmatic system. Our new ID-TIMS U-Pb zircon age of the Ristisaari Island dark wiborgite, 1627±3 Ma, is the youngest isotopic age so far determined for the plutonic rocks of the Wiborg batholith. This, combined with preexisting U-Pb zircon data, implies a minimum duration of 12 m.y. (1642–1630 Ma for the emplacement of the plutonic rocks of the batholith. Combined with data on highlevel dike rocks, a window of at least 20 m.y. (1642–1622 Ma is implied. Furthermore, as the batholith grew, the overall locus of magmatism may have shifted southwards. New whole-rock Nd isotope data on the dark wiborgite of the Ristisaari Island and three further granites of the batholith, as well as Nd (whole-rock and Sr (whole-rock, plagioclase isotope data on a spectrolite massif-type anorthosite from the east-central part of the batholith, are also presented. These data suggest that the lithosphere across the Wiborg batholith area in the southeastern part of the Svecofennian orogen may vary slightly in overall mantle separation age.

  6. Fault-controlled permeability and fluid flow in low-porosity crystalline rocks: an example from naturally fractured geothermal systems in the Southern Andes

    Arancibia, G.; Roquer, T.; Sepúlveda, J.; Veloso, E. A.; Morata, D.; Rowland, J. V.

    2017-12-01

    Fault zones can control the location, emplacement, and evolution of economic mineral deposits and geothermal systems by acting as barriers and/or conduits to crustal fluid flow (e.g. magma, gas, oil, hydro-geothermal and groundwater). The nature of the fault control permeability is critical in the case of fluid flow into low porosity/permeability crystalline rocks, since structural permeability provides the main hydraulic conductivity to generate a natural fractured system. However, several processes accompanying the failure of rocks (i.e. episodic permeability given by cycling ruptures, mineral precipitation from fluids in veins, dissolution of minerals in the vicinity of a fracture) promote a complex time-dependent and enhancing/reducing fault-controlled permeability. We propose the Southern Volcanic Zone (Southern Andes, Chile) as a case study to evaluate the role of the structural permeability in low porosity crystalline rocks belonging to the Miocene North Patagonian Batholith. Recently published studies propose a relatively well-constrained first-order role of two active fault systems, the arc-parallel (NS to NNE trending) Liquiñe Ofqui Fault System and the arc-oblique (NW trending) Andean Transverse Fault Zones, in fluid flow at crustal scales. We now propose to examine the Liquiñe ( 39°S) and Maihue ( 40°S) areas as sites of interaction between these fault systems, in order to evaluate a naturally fractured geothermal system. Preliminary results indicate upwelling of thermal water directly from fractured granite or from fluvial deposits overlying granitoids. Measured temperatures of thermal springs suggest a low- to medium-enthalpy system, which could potentially be harnessed for use in geothermal energy applications (e.g. heating, wood dryer and green house), which are much needed in Southern Chile. Future work will aim to examine the nature of structural permeability from the regional to the microscopic scale connecting the paleo- and current- fluid

  7. Reflection seismic methods applied to locating fracture zones in crystalline rock

    Juhlin, C.

    1998-01-01

    The reflection seismic method is a potentially powerful tool for identifying and localising fracture zones in crystalline rock if used properly. Borehole sonic logs across fracture zones show that they have reduced P-wave velocities compared to the surrounding intact rock. Diagnostically important S-wave velocity log information across the fracture zones is generally lacking. Generation of synthetic reflection seismic data and subsequent processing of these data show that structures dipping up towards 70 degrees from horizontal can be reliably imaged using surface seismic methods. Two real case studies where seismic reflection methods have been used to image fracture zones in crystalline rock are presented. Two examples using reflection seismic are presented. The first is from the 5354 m deep SG-4 borehole in the Middle Urals, Russia where strong seismic reflectors dipping from 25 to 50 degrees are observed on surface seismic reflection data crossing over the borehole. On vertical seismic profile data acquired in the borehole, the observed P-wave reflectivity is weak from these zones, however, strong converted P to S waves are observed. This can be explained by the source of the reflectors being fracture zones with a high P wave to S wave velocity ratio compared to the surrounding rock resulting in a high dependence on the angle of incidence for the reflection coefficient. A high P wave to S wave velocity ratio (high Poisson's ratio) is to be expected in fluid filled fractured rock. The second case is from Aevroe, SE Sweden, where two 1 km long crossing high resolution seismic reflection lines were acquired in October 1996. An E-W line was shot with 5 m geophone and shotpoint spacing and a N-S one with 10 m geophone and shotpoint spacing. An explosive source with a charge size of 100 grams was used along both lines. The data clearly image three major dipping reflectors in the upper 200 ms (600 m). The dipping ones intersect or project to the surface at/or close to

  8. Geological assessment of crystalline rock formations with a view to radioactive waste disposal

    Mather, J.D.

    1984-01-01

    Field work has been concentrated at the Altnabreac Research Site on north-east Scotland, where three deep boreholes to approximately 300 m and 24 shallow boreholes to approximately 40 m were drilled. The movement of groundwater within 300 m of the surface was investigated using a specially developed straddle packer system. Geochemical studies have demonstrated that most groundwater is dominated by recent recharge but one borehole yielded water with an age of around 10 4 years. Geophysical borehole logging has shown that the full wave train sonic logs and the acoustic logs show most promise for the assessment of crystalline rocks. In the laboratory the interaction of rocks and groundwater at the temperature/pressure conditions to be expected in a repository has established the geochemical environment to which waste canisters and backfill materials would be subjected. Other generic studies reported include the characterization of geotechnical properties of rocks at elevated temperatures and pressures, the development of a new cross-hole sinusoidal pressure test for the measurement of hydraulic properties and the use of thermal infra-red imagery to detect groundwater discharge zones

  9. Coupled THM processes in EDZ of crystalline rocks using an elasto-plastic cellular automaton

    Pan, Peng-Zhi; Feng, Xia-Ting; Huang, Xiao-Hua; Cui, Qiang; Zhou, Hui

    2009-05-01

    This paper aims at a numerical study of coupled thermal, hydrological and mechanical processes in the excavation disturbed zones (EDZ) around nuclear waste emplacement drifts in fractured crystalline rocks. The study was conducted for two model domains close to an emplacement tunnel; (1) a near-field domain and (2) a smaller wall-block domain. Goodman element and weak element were used to represent the fractures in the rock mass and the rock matrix was represented as elasto-visco-plastic material. Mohr-Coulomb criterion and a non-associated plastic flow rule were adopted to consider the viscoplastic deformation in the EDZ. A relation between volumetric strain and permeability was established. Using a self-developed EPCA2D code, the elastic, elasto-plastic and creep analyses to study the evolution of stress and deformations, as well as failure and permeability evolution in the EDZ were conducted. Results indicate a strong impact of fractures, plastic deformation and time effects on the behavior of EDZ especially the evolution of permeability around the drift.

  10. Petrographic and geochemical comparisons between the lower crystalline basement-derived section and the granite megablock and amphibolite megablock of the Eyreville B core, Chesapeake Bay impact structure, USA

    Townsend, G.N.; Gibson, R.L.; Horton, J. Wright; Reimold, W.U.; Schmitt, R.T.; Bartosova, K.

    2009-01-01

    The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite-graphite ?? fibrolite ?? garnet ?? tourmaline ?? pyrite ?? rutile ?? pyrrhotite mica schist, hornblende-plagioclase-epidote-biotite- K-feldspar-quartz-titanite-calcite amphibolite, and vesuvianite-plagioclase- quartz-epidote calc-silicate rock) are dominant in the upper part of the lower basement-derived section, and they are intruded by pegmatitic to coarse-grained granite (K-feldspar-plagioclase-quartz-muscovite ?? biotite ?? garnet) that increases in volume proportion downward. The granite megablock contains both gneissic and weakly or nonfoliated biotite granite varieties (K-feldspar-quartz-plagioclase-biotite ?? muscovite ?? pyrite), with small schist xenoliths consisting of biotite-plagioclase-quartz ?? epidote ?? amphibole. The lower basement-derived section and both megablocks exhibit similar middleto upper-amphibolite-facies metamorphic grades that suggest they might represent parts of a single terrane. However, the mica schists in the lower basement-derived sequence and in the megablock xenoliths show differences in both mineralogy and whole-rock chemistry that suggest a more mafi c source for the xenoliths. Similarly, the mineralogy of the amphibolite in the lower basement-derived section and its association with calc-silicate rock suggest a sedimentary protolith, whereas the bulk-rock and mineral chemistry of the megablock amphibolite indicate an igneous protolith. The lower basement-derived granite also shows bulk chemical and mineralogical differences from the megablock gneissic and biotite granites. ?? 2009 The Geological Society of America.

  11. Petrographic and geochemical comparisons between the lower crystalline basement-derived section and the granite megablock and amphibolite megablock of the Eyreville-B core, Chesapeake Bay impact structure

    Townsend, Gabrielle N.; Gibson, Roger L.; Horton, J. Wright; Reimold, Wolf Uwe; Schmitt, Ralf T.; Bartosova, Katerina

    2009-01-01

    The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite-graphite ± fibrolite ± garnet ± tourmaline ± pyrite ± rutile ± pyrrhotite mica schist, hornblende-plagioclase-epidote-biotite-K-feldspar-quartz-titanite-calcite amphibolite, and vesuvianite-plagioclase-quartz-epidote calc-silicate rock) are dominant in the upper part of the lower basement-derived section, and they are intruded by pegmatitic to coarse-grained granite (K-feldspar-plagioclase-quartz-muscovite ± biotite ± garnet) that increases in volume proportion downward. The granite megablock contains both gneissic and weakly or nonfoliated biotite granite varieties (K-feldspar-quartz-plagioclase-biotite ± muscovite ± pyrite), with small schist xenoliths consisting of biotite-plagioclase-quartz ± epidote ± amphibole. The lower basement-derived section and both megablocks exhibit similar middle- to upper-amphibolite-facies metamorphic grades that suggest they might represent parts of a single terrane. However, the mica schists in the lower basement-derived sequence and in the megablock xenoliths show differences in both mineralogy and whole-rock chemistry that suggest a more mafic source for the xenoliths. Similarly, the mineralogy of the amphibolite in the lower basement-derived section and its association with calc-silicate rock suggest a sedimentary protolith, whereas the bulk-rock and mineral chemistry of the megablock amphibolite indicate an igneous protolith. The lower basement-derived granite also shows bulk chemical and mineralogical differences from the megablock gneissic and biotite granites.

  12. The potential for methane hydrate formation in deep repositories of spent nuclear fuel in granitic rocks

    Tohidi, Bahman; Chapoy, Antonin; Smellie, John; Puigdomenech, Ignasi

    2010-12-01

    The main aim of this work was to establish whether the pertaining pressure and temperature conditions and dissolved gas concentration in groundwater is conducive to gas hydrate formation using a modelling approach. The hydrate stability pressure-temperature zone of dissolved methane in the presence of salt has been obtained through calculations which show that a decrease in the system pressure and/or an increase in salt concentration favours hydrate formation, as both factors reduce equilibrium gas solubility in the aqueous phase. This behaviour is unlike that of the system including a gas phase, where the water phase is always saturated with methane, and hence the methane solubility in water is not a limiting factor. The main conclusion is that hydrate formation is not possible at the reported methane concentrations and water salinities for the Forsmark and Laxemar sites in Sweden and Olkiluoto in Finland. At the highest salinities and methane concentrations encountered, namely ∼0.00073 mole fraction methane and ∼10 mass % NaCl at a depth of 1,000 m in Olkiluoto, Finland, hydrates could form if the system temperatures and pressures are below 2.5 deg C and 60 bar, respectively, i.e. values that are much lower than those prevailing at that depth (∼20 deg C and ∼100 bar, respectively). Furthermore, the calculated results provide the necessary data to estimate the effect of increase in dissolved methane concentration on potential hydrate formation, as well as two phase flow. The available depth dependency of methane concentration at the sites studied in Sweden and Finland was used in another study to estimate the diffusive flow of methane in the rock volumes. These diffusion rates, which are highest at Olkiluoto, indicate that even if the conditions were to become favourable to methane hydrate formation, then it would take several millions of years before a thin layer of hydrates could be formed, a condition which is outside the required period of satisfactory

  13. The potential for methane hydrate formation in deep repositories of spent nuclear fuel in granitic rocks

    Tohidi, Bahman; Chapoy, Antonin (Hydrafact Ltd, Inst. of Petroleum Engineering, Heriot-Watt Univ., Edinburgh (United Kingdom)); Smellie, John (Conterra AB, Uppsala (Sweden)); Puigdomenech, Ignasi (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

    2010-12-15

    The main aim of this work was to establish whether the pertaining pressure and temperature conditions and dissolved gas concentration in groundwater is conducive to gas hydrate formation using a modelling approach. The hydrate stability pressure-temperature zone of dissolved methane in the presence of salt has been obtained through calculations which show that a decrease in the system pressure and/or an increase in salt concentration favours hydrate formation, as both factors reduce equilibrium gas solubility in the aqueous phase. This behaviour is unlike that of the system including a gas phase, where the water phase is always saturated with methane, and hence the methane solubility in water is not a limiting factor. The main conclusion is that hydrate formation is not possible at the reported methane concentrations and water salinities for the Forsmark and Laxemar sites in Sweden and Olkiluoto in Finland. At the highest salinities and methane concentrations encountered, namely approx0.00073 mole fraction methane and approx10 mass % NaCl at a depth of 1,000 m in Olkiluoto, Finland, hydrates could form if the system temperatures and pressures are below 2.5 deg C and 60 bar, respectively, i.e. values that are much lower than those prevailing at that depth (approx20 deg C and approx100 bar, respectively). Furthermore, the calculated results provide the necessary data to estimate the effect of increase in dissolved methane concentration on potential hydrate formation, as well as two phase flow. The available depth dependency of methane concentration at the sites studied in Sweden and Finland was used in another study to estimate the diffusive flow of methane in the rock volumes. These diffusion rates, which are highest at Olkiluoto, indicate that even if the conditions were to become favourable to methane hydrate formation, then it would take several millions of years before a thin layer of hydrates could be formed, a condition which is outside the required period of

  14. Coupled hydromechanical paleoclimate analyses of density-dependant groundwater flow in discretely fractured crystalline rock settings

    Normani, S. D.; Sykes, J. F.; Jensen, M. R.

    2009-04-01

    A high resolution sub-regional scale (84 km2) density-dependent, fracture zone network groundwater flow model with hydromechanical coupling and pseudo-permafrost, was developed from a larger 5734 km2 regional scale groundwater flow model of a Canadian Shield setting in fractured crystalline rock. The objective of the work is to illustrate aspects of regional and sub-regional groundwater flow that are relevant to the long-term performance of a hypothetical nuclear fuel repository. The discrete fracture dual continuum numerical model FRAC3DVS-OPG was used for all simulations. A discrete fracture zone network model delineated from surface features was superimposed onto an 789887 element flow domain mesh. Orthogonal fracture faces (between adjacent finite element grid blocks) were used to best represent the irregular discrete fracture zone network. The crystalline rock between these structural discontinuities was assigned properties characteristic of those reported for the Canadian Shield at the Underground Research Laboratory at Pinawa, Manitoba. Interconnectivity of permeable fracture features is an important pathway for the possibly relatively rapid migration of average water particles and subsequent reduction in residence times. The multiple 121000 year North American continental scale paleoclimate simulations are provided by W.R. Peltier using the University of Toronto Glacial Systems Model (UofT GSM). Values of ice sheet normal stress, and proglacial lake depth from the UofT GSM are applied to the sub-regional model as surface boundary conditions, using a freshwater head equivalent to the normal stress imposed by the ice sheet at its base. Permafrost depth is applied as a permeability reduction to both three-dimensional grid blocks and fractures that lie within the time varying permafrost zone. Two different paleoclimate simulations are applied to the sub-regional model to investigate the effect on the depth of glacial meltwater migration into the subsurface. In

  15. Calculations of the Temperature Evolution of a Repository for Spent Fuel in Crystalline and Sedimentary Rocks

    Sato, R.; Sasaki, T.; Ando, K.; Smith, P.A.; Schneider, J.W.

    1998-08-01

    Thermal evolution is a factor influencing repository design, and must be considered in safety assessment, since many of the processes that affect the long-term safety are temperature dependent. This report presents calculations of the thermal evolution of a repository for spent nuclear fuel. The calculations are based on a provisional repository near-field design in which spent fuel is encapsulated in composite copper-steel canisters, which are emplaced centrally along the horizontal axes of repository tunnels, with the space around the canisters backfilled with bentonite. The temperature of these near-field components varies with time, due to the radiogenic heat produced by the spent fuel. The rate of heat production per canister depends on the initial composition of the fuel, its reactor history, the period of intermediate storage before final disposal and the loading of the canisters. The rate decreases with time, as shorter-lived radionuclides decay. The base-case calculation considers spent fuel that is assumed to generate 1000 W per canister, 40 years after unloading of the fuel from the reactor. The results of the base case calculation indicate that the temperatures at the bentonite/host rock interface, at the centre of the bentonite and at the bentonite/canister interface rise to 98 o C, 103 o C and 126 o C, respectively, before declining towards the ambient temperature of the host rock which, in the base case, is taken to be the crystalline basement of Northern Switzerland. In addition to the base case, parameter variations are examined that investigate the sensitivity of thermal evolution to alternative heat output, design specifications and to uncertainties in material properties. Key findings include (i), that an increase in heat generation to 1500 W per canister 40 years after unloading results in a significant increase of repository temperatures (e.g. at the bentonite/host rock interface, an increase of 22 o C is observed), (ii), that a decrease in

  16. Assessment of disruptive scenarios of a Canadian used fuel repository in crystalline rock

    Gobien, M.; Garisto, F.; Hunt, N.; Kremer, E.P. [Nuclear Waste Management Organization (NWMO), Toronto, Ontario (Canada)

    2015-06-15

    The NWMO has recently extended its modelling capabilities by performing simulations for four disruptive scenarios that, to date, have not yet been examined in detail. These scenarios complement those considered in an existing postclosure safety assessment for a conceptual geological repository located in a hypothetical crystalline rock formation. The four new disruptive scenarios are: Shaft Seal Failure, Undetected Fault, Open or Poorly Sealed Borehole and Open Borehole Due to Inadvertent Human Intrusion. All simulations are based on the FRAC3DVS-OPG Site-Scale Model. The Site-Scale Model includes a simplified representation of the full repository and a portion of the surrounding sub-regional flow system. All transport simulations are performed with only the radionuclide I-129. Transport rates to the surface and a domestic water supply well are compared to the Reference Case results from an earlier case study documented in Reference. (author)

  17. Assessment of disruptive scenarios of a Canadian used fuel repository in crystalline rock

    Gobien, M.; Garisto, F.; Hunt, N.; Kremer, E.P., E-mail: mgobien@nwmo.ca [Nuclear Waste Management Organization, Toronto, ON (Canada)

    2015-07-01

    The NWMO has recently extended its modelling capabilities by performing simulations for four disruptive scenarios that, to date, have not yet been examined in detail. These scenarios complement those considered in an existing postclosure safety assessment for a conceptual geological repository located in a hypothetical crystalline rock formation. The four new disruptive scenarios are: Shaft Seal Failure, Undetected Fault, Open or Poorly Sealed Borehole and Open Borehole Due to Inadvertent Human Intrusion. All simulations are based on the FRAC3DVS-OPG [1] Site-Scale Model [2]. The Site-Scale Model includes a simplified representation of the full repository and a portion of the surrounding sub-regional flow system. All transport simulations are performed with only the radionuclide I-129. Transport rates to the surface and a domestic water supply well are compared to the Reference Case results from an earlier case study documented in Reference [2]. (author)

  18. Assessment of disruptive scenarios of a Canadian used fuel repository in crystalline rock

    Gobien, M.; Garisto, F.; Hunt, N.; Kremer, E.P.

    2015-01-01

    The NWMO has recently extended its modelling capabilities by performing simulations for four disruptive scenarios that, to date, have not yet been examined in detail. These scenarios complement those considered in an existing postclosure safety assessment for a conceptual geological repository located in a hypothetical crystalline rock formation. The four new disruptive scenarios are: Shaft Seal Failure, Undetected Fault, Open or Poorly Sealed Borehole and Open Borehole Due to Inadvertent Human Intrusion. All simulations are based on the FRAC3DVS-OPG [1] Site-Scale Model [2]. The Site-Scale Model includes a simplified representation of the full repository and a portion of the surrounding sub-regional flow system. All transport simulations are performed with only the radionuclide I-129. Transport rates to the surface and a domestic water supply well are compared to the Reference Case results from an earlier case study documented in Reference [2]. (author)

  19. Evaluation of natural radioactivity in some granitic rocks in the state of Parana, Brazil and its use in civil construction; Avaliacao da radioatividade natural em algumas rochas graniticas do estado do Parana e sua utilizacao na construcao civil

    Ferreira, Ademar de Oliveira

    2013-07-01

    Primordial, or terrestrial natural radionuclides, are found in different amounts in the environment. In dwellings, an important dose increment is due to building materials, which contribute for both the external gamma dose from the radionuclides of the {sup 238}U, {sup 235}U and {sup 232}Th series and the natural {sup 40}K and the internal dose, due mainly to {sup 222}Rn inhalation. Once granitic rocks are widely used both as construction materials or structural flooring, those rocks can become an important dose source, depending on the content of concentrations of radioactivity, and the construction application. In this work, a database for granitic rocks of the crystalline shield of Parana (mainly in the Metropolitan Region of Curitiba, RMC), used in civil construction, was generated, evaluating in terms of radiological protection the external and internal dose increments, caused by the use of these materials. Also, possible correlations between the {sup 226}Ra activity concentration, the {sup 222}Rn exhalation rate, density, porosity and chemical composition (oxide content) in these samples had been studied. The external dose was assessed by gamma-ray spectrometry with High-Purity Germanium detectors, where the activity concentration of the radionuclides {sup 232}Th, {sup 226}Ra and {sup 40}K are the parameters used in dosimetric models (Dosimetric Indexes), which established limits in accordance with the form, amount and application of material of construction. For the calculation of the annual effective external dose it was assumed a room model with dimensions of 4 m x 5 m x 2:8 m and all walls internally covered with 2 cm thickness of granite and an annual exposure time of 7000 h as suggested by the European Commission of Radiological Protection for internal superficial coating materials. The internal exposure was assessed from the radon concentration in the air of the room model, simulated from the superficial exhalation rate of {sup 222}Rn. The exhalation

  20. The origin of groundwater salinity in granitic rocks: identification and characterisation of chloride sources; Origine de la salinite des eaux souterraines en milieu granitique: identification et caracterisation des sources de chlorure

    Savoye, S.

    1998-04-29

    Hydrogeological research in crystalline rocks, developed either in geothermics or in feasibility studies for geological disposal of radioactive waste, points out a wide range of chloride contents in associated groundwaters. The aim of this dissertation is to identify the possible origins of chloride in groundwaters within different geological conditions. The three possible chloride reservoirs (chloride-bearing minerals, fluid inclusions, micro-porosity) located in rock have been characterised by studying samples from eight granitic sites with different technical approaches (electronic microbeam, alkaline fusion, micro-thermometry, crush-leaching, diffusion experiment). Firstly, this allows the definition of a new typology of the sites, by considering not only hydrogeological features but also occurrence of salt-rich fluid inclusions with sedimentary origin. Secondly, the use of tracers (such as Cl/Br ratio, {delta}{sup 37}Cl) and mass balance calculations shows that the contribution of fluid inclusions trapped in quartz and chloride-bearing minerals cannot account for the high salinity of groundwater. In this case, the chloride origin could be of sedimentary type. Chloride would be stored in micro-porosity and in fluid inclusions trapped in carbonates. Thirdly, we have pointed out the importance of micro-porosity, acting more as a sieve and a buffer than as a source. Finally, we have shown that the low salinity of groundwaters has not always an internal origin. (author) 187 refs.

  1. VSP in crystalline rocks - from downhole velocity profiling to 3-D fracture mapping

    Cosma, C.; Heikkinen, P.; Keskinen, J.; Enescu, N.

    1998-01-01

    VSP surveys have been carried out at several potential nuclear waste disposal sites in Finland since the mid 80s. To date, more than 200 three-component profiles have been measured. The main purpose of the surveys was to detect fracture zones in the crystalline bedrock and to determine their position. Most seismic events could be linked to zones of increased fracturing observed in the borehole logs. The more pronounced seismic reflectors could be correlated with hydrogeologically significant zones, which have been the main targets in the investigations. Processing and interpretation methods have been developed specifically for VSP surveys in crystalline rocks: Weak reflections from thin fracture zones are enhanced by multi-channel filtering techniques based on the Radon transform. The position and orientation of the fracture zones are determined by polarisation analysis and by combining data from several shot points. The compilation of the results from several boreholes gives a comprehensive image of the fracture zones at the scale of the whole site. The discussion of the methodology is based on examples from the Olkiluoto site, in SW Finland

  2. K, Rb and Sr abundances and Sr isotopic composition of the Tanzawa granitic and associated gabbroic rocks, Japan: low-potash island arc plutonic complex

    Ishizaka, K.; Yanagi, T.

    1977-01-01

    The granitic and associated gabbroic rocks of the Tanzawa plutonic complex of Miocene age occurring in the northern part of the Izu-Bonin arc are characterized by low abundances of K (229-6790 ppm) and Rb (0.414-12.1 ppm), low K 2 O/Na 2 O ratios (0.037-0.21), moderately high K/Rb ratios (541-630), low Rb/Sr ratios (0.00137-0.0579) and low initial 87 Sr/ 86 Sr ratios (0.70332-0.70372). This indicates that acid to intermediate plutonic rocks with these geochemical characteristics also occur in island arc environments besides mid-oceanic ridge environments. They represent, together with associated gabbroic rocks, a low-potash island arc plutonic complex and are expected to occur beneath young island arcs, although now unexposed. The Tanzawa plutonic complex may have been formed by differentiation of low-K calc-alkaline magma. (Auth.)

  3. Airborne radiometric anomalies caused by late kinematic granite rocks in the Molson Lake-Red Sucker Lake area, east-central Manitoba

    Weber, W.; Schledewitz, D.C.P.; Soonawala, N.M.

    1982-01-01

    Geological mapping with simultaneous ground gamma ray spectrometer surveys in an area with a chain of airborne radiometric anomalies of greater than 2 ppm eU indicate uranium enrichment in late kinematic pink leucogranitic rocks including granites, alaskites, and syenites which form dykes, stocks and small plutons in a batholithic tonalite - granodiorite complex. Field geolocial evidence suggests that the potassium-rich rocks were formed by hydrothermal solutions and that at least some of them are metasomatic replacement bodies. Results of geophysical grid survey over a pronounced anomaly indicate that it is caused by a significant volume of leucogranitic rocks with an unusually high background concentration of uranium averaging 25 ppm eU. The uranium seems to be associated with hematite which coats mineral grains and fills small fractures

  4. Interaction between clay-based shaft seal components and crystalline host rock

    Priyanto, D.; Dixon, D.; Man, A.

    2010-01-01

    Document available in extended abstract form only. The Government of Canada has accepted the Nuclear Waste Management Organization's (NWMO) recommendation of Adaptive Phased Management (APM) as the long-term management approach for Canada's used nuclear fuel. APM ultimately involves the isolation and containment of used nuclear fuel deep in a Deep Geological Repository (DGR). On completion of waste emplacement operation and during repository closure, shaft seals, comprising clay-based shaft seal components, will be installed at strategic locations, such as where significant fracture zones (FZs) are located. The primary function of a shaft seal is to limit and prevent short-circuiting of the groundwater flow regime via the shaft. Currently, at Atomic Energy of Canada Limited's Underground Research Laboratory (URL) a full-scale shaft seal is being constructed at the intersection of a low dipping thrust fault called FZ 2 as part of the overall URL decommissioning activities. Both crystalline rock and sedimentary rock are considered potentially suitable host rocks formations for a DGR. This paper presents the results of numerical simulation of a shaft seal installed in moderately to sparsely fractured crystalline rock (MFR). The shape and thickness of the shaft seal modelled for a DGR in this exercise are similar to the shaft seal at the URL, but in the modelling exercise it is given a larger diameter (i.e. 7.30 m) equal to the assumed diameter of a production shaft of a repository. The seal consists of a blended bentonite-sand (BS) component that is constrained between two massive concrete seals. Dense backfill (DBF) materials are installed above and below the concrete seals (CS). The concrete seals are keyed into the access shaft to better anchor the concrete units in place and in order to restrain the swelling of the bentonite-sand component of the seal as it hydrates. The reference geosphere in the proposed work is MFR similar to the rock conditions

  5. Time-Dependent Behaviors of Granite: Loading-Rate Dependence, Creep, and Relaxation

    Hashiba, K.; Fukui, K.

    2016-07-01

    To assess the long-term stability of underground structures, it is important to understand the time-dependent behaviors of rocks, such as their loading-rate dependence, creep, and relaxation. However, there have been fewer studies on crystalline rocks than on tuff, mudstone, and rock salt, because the high strength of crystalline rocks makes the detection of their time-dependent behaviors much more difficult. Moreover, studies on the relaxation, temporal change of stress and strain (TCSS) conditions, and relations between various time-dependent behaviors are scarce for not only granites, but also other rocks. In this study, previous reports on the time-dependent behaviors of granites were reviewed and various laboratory tests were conducted using Toki granite. These tests included an alternating-loading-rate test, creep test, relaxation test, and TCSS test. The results showed that the degree of time dependence of Toki granite is similar to other granites, and that the TCSS resembles the stress-relaxation curve and creep-strain curve. A viscoelastic constitutive model, proposed in a previous study, was modified to investigate the relations between the time-dependent behaviors in the pre- and post-peak regions. The modified model reproduced the stress-strain curve, creep, relaxation, and the results of the TCSS test. Based on a comparison of the results of the laboratory tests and numerical simulations, close relations between the time-dependent behaviors were revealed quantitatively.

  6. Electronic Structure of the Metastable Epitaxial Rock-Salt SnSe {111} Topological Crystalline Insulator

    Wencan Jin

    2017-10-01

    Full Text Available Topological crystalline insulators have been recently predicted and observed in rock-salt structure SnSe {111} thin films. Previous studies have suggested that the Se-terminated surface of this thin film with hydrogen passivation has a reduced surface energy and is thus a preferred configuration. In this paper, synchrotron-based angle-resolved photoemission spectroscopy, along with density functional theory calculations, is used to demonstrate that a rock-salt SnSe {111} thin film epitaxially grown on Bi_{2}Se_{3} has a stable Sn-terminated surface. These observations are supported by low-energy electron diffraction (LEED intensity-voltage measurements and dynamical LEED calculations, which further show that the Sn-terminated SnSe {111} thin film has undergone a surface structural relaxation of the interlayer spacing between the Sn and Se atomic planes. In sharp contrast to the Se-terminated counterpart, the observed Dirac surface state in the Sn-terminated SnSe {111} thin film is shown to yield a high Fermi velocity, 0.50×10^{6}  m/s, which suggests a potential mechanism of engineering the Dirac surface state of topological materials by tuning the surface configuration.

  7. Generic repository concept for RBMK-1500 spent nuclear fuel disposal in crystalline rocks in Lithuania

    Poskas, P.; Brazauskaite, A.; Narkunas, E.; Smaizys, A.; Sirvydas, A.

    2006-01-01

    During 2002-2005 investigations on possibilities to dispose of spent nuclear fuel (SNF) in Lithuania were performed with support of Swedish experts. Disposal concept for RBMK-1500 SNF in crystalline rocks in Lithuania is based on Swedish KBS-3 concept with SNF emplacement into the copper canister with cast iron insert. The bentonite and its mixture with crushed rock are also foreseen as buffer and backfill material. In this paper modelling results on thermal, criticality and other important disposal characteristics for RBMK-1500 SNF fuel emplaced in copper canisters are presented. Based on thermal calculations, the distances between the canisters and between the tunnels were justified. Criticality calculations for the canister with fresh fuel with 2.8 % 235 U enrichment demonstrated that effective neutron multiplication factor k eff values are less than allowable value of 0.95. Dose calculations have shown that total equivalent dose rate from the canister with 50 years stored RBMK-1500 SNF is rather high and is defined mainly by the γ radiation. (author)

  8. Interaction between clay-based sealing components and crystalline host rock

    Priyanto, D. G.; Dixon, D. A.; Man, A. G.

    The results of hydraulic-mechanical (H-M) numerical simulation of a shaft seal installed at a fracture zone (FZ) in a crystalline host rock using the finite element method are presented. The primary function of a shaft seal is to limit short-circuiting of the groundwater flow regime via the shaft in a deep geological repository. Two different stages of system evolution were considered in this numerical modelling. Stage 1 simulates the groundwater flow into an open shaft, prior to seal installation. Stage 2 simulates the groundwater flow into the shaft seal after seal installation. Four different cases were completed to: (i) evaluate H-M response due to the interaction between clay-based sealing material and crystalline host rock in the shaft seal structure; (ii) quantify the effect of the different times between the completion of the shaft excavation and the completion of shaft seal installation on the H-M response; and (iii) define the potential effects of different sealing material configurations. Shaft sealing materials include the bentonite-sand mixture (BSM), dense backfill (DBF), and concrete plug (CP). The BSM has greater swelling capacity and lower hydraulic conductivity ( K) than the DBF. The results of these analyses show that the decrease of the pore water pressure is concentrated along the fracture zone (FZ), which has the greatest K. As the time increases, the greatest decrease in pore water pressure is found around the FZ. Following FZ isolation and the subsequent filling of the shaft with water as it floods, the pore water pressure profile tends to recover back to the initial conditions prior to shaft excavation. The majority of the fluids that ultimately saturate the centre of the shaft seal flow radially inwards from the FZ. The time between the completion of the shaft excavation and the completion of shaft seal installation has a significant effect on the saturation time. A shorter time can reduce the saturation time. Since most of the inflow

  9. Critical Evolution of Damage Toward System-Size Failure in Crystalline Rock

    Renard, François; Weiss, Jérôme; Mathiesen, Joachim; Ben-Zion, Yehuda; Kandula, Neelima; Cordonnier, Benoît

    2018-02-01

    Rock failure under shear loading conditions controls earthquake and faulting phenomena. We study the dynamics of microscale damage precursory to shear faulting in a quartz-monzonite rock representative of crystalline rocks of the continental crust. Using a triaxial rig that is transparent to X-rays, we image the mechanical evolution of centimeter-size core samples by in situ synchrotron microtomography with a resolution of 6.5 μm. Time-lapse three-dimensional images of the samples inside the rig provide a unique data set of microstructural evolution toward faulting. Above a yield point there is a gradual weakening during which microfractures nucleate and grow until this damage span the whole sample. This leads to shear faults oriented about 30° to the main compressive stress in agreement with Anderson's theory and macroscopic failure. The microfractures can be extracted from the three-dimensional images, and their dynamics and morphology (i.e., number, volume, orientation, shape, and largest cluster) are quantified as a function of increasing stress toward failure. The experimental data show for the first time that the total volume of microfractures, the rate of damage growth, and the size of the largest microfracture all increase and diverge when approaching faulting. The average flatness of the microfractures (i.e., the ratio between the second and third eigenvalues of their covariance matrix) shows a significant decrease near failure. The precursors to faulting developing in the future faulting zone are controlled by the evolving microfracture population. Their divergent dynamics toward failure is reminiscent of a dynamical critical transition.

  10. Methods and uncertainty estimations of 3-D structural modelling in crystalline rocks: a case study

    R. Schneeberger

    2017-09-01

    Full Text Available Exhumed basement rocks are often dissected by faults, the latter controlling physical parameters such as rock strength, porosity, or permeability. Knowledge on the three-dimensional (3-D geometry of the fault pattern and its continuation with depth is therefore of paramount importance for applied geology projects (e.g. tunnelling, nuclear waste disposal in crystalline bedrock. The central Aar massif (Central Switzerland serves as a study area where we investigate the 3-D geometry of the Alpine fault pattern by means of both surface (fieldwork and remote sensing and underground ground (mapping of the Grimsel Test Site information. The fault zone pattern consists of planar steep major faults (kilometre scale interconnected with secondary relay faults (hectometre scale. Starting with surface data, we present a workflow for structural 3-D modelling of the primary faults based on a comparison of three extrapolation approaches based on (a field data, (b Delaunay triangulation, and (c a best-fitting moment of inertia analysis. The quality of these surface-data-based 3-D models is then tested with respect to the fit of the predictions with the underground appearance of faults. All three extrapolation approaches result in a close fit (> 10 % when compared with underground rock laboratory mapping. Subsequently, we performed a statistical interpolation based on Bayesian inference in order to validate and further constrain the uncertainty of the extrapolation approaches. This comparison indicates that fieldwork at the surface is key for accurately constraining the geometry of the fault pattern and enabling a proper extrapolation of major faults towards depth. Considerable uncertainties, however, persist with respect to smaller-sized secondary structures because of their limited spatial extensions and unknown reoccurrence intervals.

  11. Methods and uncertainty estimations of 3-D structural modelling in crystalline rocks: a case study

    Schneeberger, Raphael; de La Varga, Miguel; Egli, Daniel; Berger, Alfons; Kober, Florian; Wellmann, Florian; Herwegh, Marco

    2017-09-01

    Exhumed basement rocks are often dissected by faults, the latter controlling physical parameters such as rock strength, porosity, or permeability. Knowledge on the three-dimensional (3-D) geometry of the fault pattern and its continuation with depth is therefore of paramount importance for applied geology projects (e.g. tunnelling, nuclear waste disposal) in crystalline bedrock. The central Aar massif (Central Switzerland) serves as a study area where we investigate the 3-D geometry of the Alpine fault pattern by means of both surface (fieldwork and remote sensing) and underground ground (mapping of the Grimsel Test Site) information. The fault zone pattern consists of planar steep major faults (kilometre scale) interconnected with secondary relay faults (hectometre scale). Starting with surface data, we present a workflow for structural 3-D modelling of the primary faults based on a comparison of three extrapolation approaches based on (a) field data, (b) Delaunay triangulation, and (c) a best-fitting moment of inertia analysis. The quality of these surface-data-based 3-D models is then tested with respect to the fit of the predictions with the underground appearance of faults. All three extrapolation approaches result in a close fit ( > 10 %) when compared with underground rock laboratory mapping. Subsequently, we performed a statistical interpolation based on Bayesian inference in order to validate and further constrain the uncertainty of the extrapolation approaches. This comparison indicates that fieldwork at the surface is key for accurately constraining the geometry of the fault pattern and enabling a proper extrapolation of major faults towards depth. Considerable uncertainties, however, persist with respect to smaller-sized secondary structures because of their limited spatial extensions and unknown reoccurrence intervals.

  12. Modelling long-term redox processes and oxygen scavenging in fractured crystalline rocks

    Sidborn, Magnus

    2007-10-01

    Advanced plans for the construction of a deep geological repository for highly radioactive wastes from nuclear power plants have evolved during the past decades in many countries including Sweden. As part of the Swedish concept, the waste is to be encapsulated in canisters surrounded by low permeability backfill material. The copper canisters will be deposited at around 500 metres depth in granitic rock, which acts as a natural barrier for the transport of radionuclides to the ground surface. These natural and engineered barriers are chosen and designed to ensure the safety of the repository over hundred of thousands of years. One issue of interest for the safety assessment of such a repository is the redox evolution over long times. An oxidising environment would enhance the corrosion of the copper canisters, and increases the mobility of any released radionuclides. In the first part of the present thesis, the ability of the host rock to ensure a reducing environment at repository depth over long times was studied. A model framework was developed with the aim to capture all processes that are deemed to be important for the scavenging of intruding oxygen from the ground surface over long times. Simplifications allowing for analytical solutions were introduced for transparency reasons so that evaluation of results is straight-forward, and so that uncertain parameter values easily can be adjusted. More complex systems were solved numerically for cases when the analytical simplifications are not applicable, and to validate the simplifications underlying the analytical solutions. Results were presented for prevailing present day conditions as well as for conditions deemed to be likely during the melting phase of a period of glaciation. It was shown that the hydraulic properties have a great influence on the oxygen intrusion length downstream along flow-paths in the rock. An important parameter that determines the extent of interaction between the dissolved oxygen and

  13. Major and minor elements and traces in igneous rocks from crystalline basement of Parana by X-ray fluorescence; Elementos maiores, menores e tracos, em rochas igneas do escudo cristalino paranaense por fluorescencia de raios-X

    Ferreira, Ademar O.; Pecequilo, Brigitte R.S.; Scapin, Marcos A.; Salvador, Vera L.R., E-mail: aoferreira@ipen.br, E-mail: brigitte@ipen.br, E-mail: mascapin@ipen.br, E-mail: vsalvado@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Major and minor components of 30 acid and basic igneous rocks (granites, syenites, riolites and a basalt) of the Parana state crystalline basement were determined by X-ray fluorescence spectrometry (WDXRF), in order to evaluate the similarity in terms of the compositional content. The corrections of interelements effects (absorption/intensification) were performed by means of the fundamental parameters (FP) method. The methodology was validated using a certificated reference material. The main oxides found associated with the quantified elements are SiO{sub 2}, Al{sub 2}O{sub 3}, Na{sub 2}O, K{sub 2}O, Fe{sub 2}O{sub 3}, CaO, MgO, TiO{sub 2}, P{sub 2}O{sub 5}, MnO, SO{sub 3}, NiO, ZnO, Rb{sub 2}O. Through statistical analysis, the studied samples were organized in 3 groups of similar compositions: syenites, light granites and basalt and dark granites. The results show that the WDXRF technique is a robust tool that enables distinction even between similar geological samples. (author)

  14. Long term thermo-hydro-mechanical interaction behavior study of the saturated, discontinuous granitic rock mass around the radwaste repository using a steady state flow algorithm

    Kim, Jhin Wung; Bae, Dae Suk; Kang, Chul Hyung; Choi, Jong Won [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-02-01

    The objective of the present study is to understand the long term (500 years) thermo-hydro-mechanical interaction behavior of the 500 m depth underground radwaste repository in the saturated, discontinuous granitic rock mass using a steady state flow algorithm. The numerical model includes a saturated granitic rock mass with joints around the repository and a 45 .deg. C fault passing through the tunnel roof-wall intersection, and a canister with PWR spent fuels surrounded by the compacted bentonite and mixed-bentonite. Barton-Bandis joint constitutive model from the UDEC code is used for the joints. For the hydraulic analysis, a steady state flow algorithm is used for the groundwater flow through the rock joints. For the thermal analysis, heat transfer is modeled as isotropic conduction and heat decays exponentially with time. The results show that the variations of the hydraulic aperture, hydraulic conductivity, normal stress, normal displacements, and shear displacements of the joints are high in the vicinity of the repository and stay fairly constant on the region away from the repository. 14 refs., 15 figs., 11 tabs. (Author)

  15. Geothermal potential of Caledonian granites underlying Upper Palaeozoic sedimentary basins astride the Iapetus Suture Zone in Ireland

    Fritschle, Tobias; Daly, J. Stephen; Whitehouse, Martin J.; McConnell, Brian; Buhre, Stephan

    2014-05-01

    Upper Palaeozoic sedimentary basins in Ireland overlie crystalline rocks within the Caledonian Iapetus Suture Zone. Beneath these basins, Lower Palaeozoic rocks, formed and deformed during the Caledonian orogenic cycle, were intruded by c. 420-390 Ma late-tectonic granites at various tectonic levels. These include the subsurface Kentstown and Glenamaddy granites discovered by mineral exploration drilling. While these granites comprise actual targets for Enhanced Geothermal System (EGS) exploration, several others likely exist based on geophysical considerations. In order to test the regional geothermal potential, the buried granites as well as analogue exposed rocks are being investigated geochemically. The geothermal potential of the intrusives depends on their heat production rate (HPR), which is calculated using rock density and concentrations of the heat producing elements (HPE) uranium, thorium and potassium. In spite of their close spacing and similar ages, the whole-rock geochemistry of the granites varies significantly, but with no obvious geographical control (Fritschle et al., 2013; 2014). The granite HPR values range from 1.4 μW/m3 for the Dhoon Granite (Isle of Man) to 4.9 μW/m3 for the Drogheda Granite (Ireland). This compares with the average HPR for a 'typical' granite of 2.7 μW/m3 (Goldstein et al., 2009). It is demonstrated that an elevated HPR of a granite can be related to enrichment in one of the HPE alone (e.g., uranium-enrichment in the Foxdale Granite (Isle of Man), or thorium-enrichment in the Drogheda Granite). Enrichment in HPE in a granite may occur due to different reasons including hydrothermal (re-) distribution of uranium, or the assimilation of thorium-rich wall-rocks. Hence, the distribution of the HPE in particular minerals, veins and source lithologies, along with the petrophysical characteristics of the sedimentary basins and the granites' petrogenesis, are currently being investigated as possible mechanisms controlling their

  16. The effect of secondary apatite on the initial 87Sr/86Sr ratio determination in granitic rocks: a case study of the Tadamigawa pluton, northeastern Japan

    Wakasugi, Y.; Ichino, K.; Tanioka, Y.; Wakaki, S.; Tsuboi, M.; Ishikawa, T.

    2017-12-01

    Apatite is a major accessory mineral in igneous rocks. Because Rb contents in apatite are very low, 87Sr/86Sr ratios of magmatic apatite are useful to estimate the initial 87Sr/86Sr ratio (SrI) of igneous rocks. Secondary post-magmatic event such as hydrothermal alteration may also crystallize secondary apatite, which may inhibit the estimation of SrI of igneous rocks. In this study, we examine the effects of secondary apatite on the initial 87Sr/86Sr ratio determination of granitic rocks by using acid leaching technique. Leached apatite samples were first separated from the whole rock powder as a heavy mineral fraction by heavy liquid technique, and the heavy mineral fraction was then leached by 3 M HNO3. The isotopic ratios of Sr and the concentrations of Rb and Sr were analyzed by TIMS and ICP-MS at Kochi Core Center, respectively. The Tadamigawa Older-stage granites, which locate in the Taishaku Mountains at the northeastern part of Japan, intrude into the Ashio Jurassic complex, and the ages of these rocks are late Cretaceous to Paleogene. The U-Pb ages of zircon and the K-Ar ages of biotite for these rocks are c. 100 Ma [1, 2]. Rb-Sr whole-rock isochron age of the pluton is 96.5 ± 1.3 Ma (SrI = 0.70534 ± 0.00003) and it is concordant with other radiometric ages. Rb-Sr mineral isochron ages range from 84.4 to 97.3 Ma and these ages are relatively younger than the Rb-Sr whole-rock isochron age. The difference among radiometric ages may reflect the difference of the closure temperature in each isotopic system. The Tadamigawa Older-stage granites have SrI for Rb-Sr mineral isochron range from 0.7053 to 0.7061 and are very similar to that (0.70534) for Rb-Sr whole-rock isochron. These may suggest that the Tadamigawa Older-stage granites are generated from same parental magma. However, 87Sr/86Sr ratios of the leached apatite samples were 0.70544-0.70856 and are relatively higher than SrI obtained from the Rb-Sr mineral isochrons (0.7053-0.7061). This result

  17. Immobilization of uranium and neptunium by microorganisms in subsurface crystalline rock environments

    Krawczyk-Baersch, Evelyn; Schmeide, Katja; Bok, Frank [Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, P.O. Box 51 01 19, D-01314 Dresden (Germany); Pedersen, Karsten [Department of Civil and Environmental Engineering, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden)

    2014-07-01

    In crystalline rock, the dominant transport medium for radionuclides is groundwater flowing through subsurface fractures. Since groundwater is containing microorganisms, fracture surfaces support biological growth of microbial communities, the so-called bio-films. The microbial diversity of these bio-films depends on the microbial consortia and the chemical composition of the fracture water. Subsurface bio-films have a significant effect on the adsorption capacity of host rock formations by forming a barrier between the rock surface and the groundwater. They can significantly affect subsurface biogeochemical interactions, leading to the immobilization and adsorption of radionuclides. Microbial studies were performed to evaluate the relevance of microbial processes for the immobilization of radionuclides in a deep crystalline repository for high-level radioactive waste. Studies were performed in Olkiluoto, in the rock characterization facility ONKALO in Finland, and in the Aespoe Hard Rock Laboratory (HRL) in Sweden. Massive 5-10-mm thick bio-films were observed in both sites attached to tunnel walls where groundwater was seeping from bedrock fractures. In experiments the effect of uranium on bio-films was studied on site in the ONKALO tunnel by adding UO{sub 2}(ClO{sub 4}){sub 2} with a final U-concentration of 1.0x10{sup -5} M to the fracture water in a self-constructed flow cell by using detached bio-film samples. bio-film specimens collected for transmission electron microscopy studies indicated that uranium in the bio-film was immobilized intracellularly in microorganisms as needle-shaped uranyl phosphate minerals, similar to meta-Autunite (Ca[UO{sub 2}]{sub 2}[PO{sub 4}]{sub 2}.10-12H{sub 2}O). In contrast, thermodynamic calculation of the theoretical predominant fields of uranium species and time-resolved laser fluorescence spectroscopy showed that the formation of aqueous uranium carbonate species Ca{sub 2}UO{sub 2}(CO{sub 3}){sub 3} and Mg{sub 2}UO{sub 2

  18. Geochemical simulation of the evolution of granitic rocks and clay minerals submitted to a temperature increase in the vicinity of a repository for spent nuclear fuel

    Fritz, B.; Kam, M.; Tardy, Y.

    1984-07-01

    The alteration of a granitic rock around a repository for spent nuclear fuel has been simulated considering the effect of an increase of temperature due to this kind of induced geothermal system. The results of the simulation have been interpreted in terms of mass transfer and volumic consequences. The alteration proceeds by dissolution of minerals (with an increase of the volumes of fissures and cracks) and precipitation of secondary miminerals as calcite and clay minerals particularly (with a decrease of the porosity). The increase of the temperature from 10 degrees C to about 100 degrees C will favour the alteration of the granitic rock around the repository by the solution filling the porosity. The rock is characterized by a very low fissure porosity and a consequent very low water velocity. This too, favours intense water rock interactions and production of secondary clays and the total possible mass transfer will decrease the porosity. A combination of these thermodynamic mass balance calculations with a kinetic approach of mineral dissolutions gives a first attempt to calibrate the modelling in the time scale: the decrease of porosity can be roughly estimated between 2 and 20% for 100,000 years. The particular problem of Na-bentonites behaviour in the proximate vicinity of the repository has been studied too. One must distinguish between two types of clay-water interactions: -within the rock around the repository, Na-bentonites should evolute with illitization in slighltly open system with low clay/water ratios, -within the repository itself, the clay reacts in a closed system for a long time with high clay/water ratios and a self-buffering effect should maintain the bentonite type. This chemical buffering effect is a positive point for the use of this clay as chemical barrier. (Author)

  19. Estimated method of permeability in the granitic rocks by geophysical loggings; Butsuri kenso shuho ni yoru kakoganchu no tosuisei ni kansuru ichikosatsu

    Matsuoka, K; Hashimoto, N. [Geophysical Surveying and Consulting Co. Ltd., Tokyo (Japan)]Ogata, N. [Power Reactor and Nuclear Fuel Development Corp., Tokyo (Japan)

    1997-10-22

    Water permeability in granite is estimated by performing geophysical investigation using a 500m-deep test hole drilled in granitic rocks in the vicinity of a Tono mine. The investigation consists of flowmeter logging and geophysical logging. In flowmeter logging, a probe is moved up and down in the hole at a constant speed by use of a cable, and the cable speed and impeller revolution are used to workout the relative speed of the fluid in the hole. In the geophysical logging, a probe attached to the leading end of a logging cable is replaced with other probes so as to acquire different geophysical data. In a hole drilled in a crack-abundant rockbed such as a granitic rockbed, the inflow and outflow of ground water is governed mainly by water-permeable crack zones, and the result of the flowmeter logging show that this hole has three highly water-permeable zones. Using the results of the loggings, a correlative equation is worked out between changes in flow speed and changes in permeability index obtained by hydraulics tests. Among the various results achieved by the geophysical logging, a fine correlationship is found between an equation relative to permeability obtained using electricity and density and water-permeability indexes obtained by hydraulic tests conducted in situ. 4 refs., 8 figs., 1 tab.

  20. Fractures inside crystalline rocks. Effects of deformations on fluid circulations; Fractures dans les roches cristallines. Effets des deformations sur les circulations de fluides

    Gentier, S

    2005-07-01

    The modeling of fluid flows inside granite massifs is an important task for the evaluation of the feasibility of radioactive waste storage inside such formations. This document makes a synthesis of the works carried out since about 15 years, in particular by the French bureau of geological and mining research (BRGM), about the hydro-mechanical behaviour of a fracture and about the hydrodynamical characterization of fracture networks inside crystalline rocks: 1 - introduction; 2 - hydro-mechanical behaviour under normal stress: experimental results (hydro-mechanical behaviour, flow regimes, mechanical behaviour, test protocol, complementary tests, influence of samples size), geometrical interpretation of experimental results (relation with walls geometry, relation with voids geometry, relation with contacts geometry), hydro-mechanical modeling (hydraulic modeling, mechanical modeling); 3 - from the hydro-mechanical behaviour under normal stress to the coupling with heat transfers and chemistry: experiment for the study of the chemo-thermo-hydro-mechanical coupling (experimental results, relation with walls morphology), thermo-hydro-mechanical experiments, thermo-hydro-chemical experiments with fractures, conclusions; 4 - hydro-mechanical behaviour during shear: experimental results, geometrical interpretation (relation with the geometry of damaged zones, relation with voids geometry, relation with walls geometry), hydro-mechanical modeling (mechanical modeling, hydro-mechanical modeling of the behaviour during shear). (J.S.)

  1. Rb-Sr whole-rock and mineral ages, K-Ar, 40Ar/39Ar, and U-Pb mineral ages, and strontium, lead, neodymium, and oxygen isotopic compositions for granitic rocks from the Salinian Composite Terrane, California:

    Kistler, R.W.; Champion, D.E.

    2001-01-01

    This report summarizes new and published age and isotopic data for whole-rocks and minerals from granitic rocks in the Salinian composite terrane, California. Rubidium-strontium whole-rock ages of plutons are in two groups, Early Cretaceous (122 to 100 Ma) and Late Cretaceous (95 to 82 Ma). Early Cretaceous plutons occur in all granitic rock exposures from Bodega Head in the north to those from the Santa Lucia and Gabilan Ranges in the central part of the terrane. Late Cretaceous plutons have been identified in the Point Reyes Peninsula, the Santa Lucia and the Gabilan Ranges, and in the La Panza Range in the southern part of the terrane. Ranges of initial values of isotopic compositions are 87Sr/86Sr, 0.7046-0.7147, δ18O, +8.5 to +12.5 per mil, 206Pb/204Pb, 18.901-19.860, 207Pb/204Pb, 15.618-15.814, 208Pb/204Pb, 38.569- 39.493, and εNd, +0.9 to -8.6. The initial 87Sr/86Sr=0.706 isopleth is identified in the northern Gabilan Range and in the Ben Lomond area of the Santa Cruz Mountains, in Montara Mountain, in Bodega Head, and to the west of the Farallon Islands on the Cordell Bank. This isotopic boundary is offset about 95 miles (160km) by right-lateral displacements along the San Gregorio-Hosgri and San Andreas fault systems.

  2. Continuum-based DFN-consistent simulations of oxygen ingress in fractured crystalline rocks

    Trinchero, P.; Puigdomenech, I.; Molinero, J.; Ebrahimi, H.; Gylling, B.; Svensson, U.; Bosbach, D.; Deissmann, G.

    2016-12-01

    The potential transient infiltration of oxygenated glacial meltwater into initially anoxic and reducing fractured crystalline rocks during glaciation events is an issue of concern for some of the prospected deep geological repositories for spent nuclear fuel. Here, this problem is assessed using reactive transport calculations. First, a novel parameterisation procedure is presented, where flow, transport and geochemical parameters (i.e. hydraulic conductivity, effective/kinetic porosity, and mineral specific surface and abundance) are defined on a finite volume numerical grid based on the (spatially varying) properties of an underlying Discrete Fracture Network (DFN). Second, using this approach, a realistic reactive transport model of Forsmark, i.e. the selected site for the proposed Swedish spent nuclear fuel repository, is implemented. The model consists of more than 70 million geochemical transport degrees of freedom and simulates the ingress of oxygen-rich water from the recharge area of the domain and its depletion due to reactions with the Fe(II) mineral chlorite. Third, the calculations are solved in the supercomputer JUQUEEN of the Jülich Supercomputing Centre. The results of the simulations show that oxygen infiltrates relatively quickly along fractures and deformation zones until a steady state profile is reached, where geochemical reactions counterbalance advective transport processes. Interestingly, most of the iron-bearing minerals are consumed in the highly conductive zones, where larger mineral surfaces are available for reactions. An analysis based on mineral mass balance shows that the considered rock medium has enough capacity to buffer oxygen infiltration for a long period of time (i.e. some thousand years).

  3. HRL Aespoe - two-phase flow experiment - gas and water flow in fractured crystalline rock

    Kull, H.; Liedtke, L.

    1998-01-01

    (The full text of the contribution follows:) Gas generated from radioactive waste may influence the hydraulic and mechanical properties of the man-made barriers and the immediate surroundings of the repository. Prediction of alteration in fractured crystalline rock is difficult. There is a lack of experimental data, and calibrated models are not yet available. Because of the general importance of this matter the German Federal Ministry for Education, Science, Research and Technology decided to conduct a two-phase flow study at HRL Aespoe within the scope of the co-operation agreement with SKB. Within the presentation an overview of field experiments and modelling studies scheduled until end of '99 are given. Conceptual models for one- and two-phase flow, methodologies and with respect to numerical calculations necessary parameter set-ups are discussed. Common objective of in-situ experiments is to calibrate flow models to improve the reliability of predictions for gas migration through fractured rock mass. Hence, in a defined dipole flow field in niche 2/715 at HRL Aespoe effective hydraulic parameters are evaluated. Numerical modelling of non-isothermal, two-phase, two-component processes is feasible only for two-dimensional representation of a porous medium. To overcome this restriction a computer program will be developed to model three-dimensional, fractured, porous media. Rational aspects of two-phase flow studies are for the designing of geotechnical barriers and for the long-term safety analysis of potential radionuclide transport in a future repository required for the licensing process

  4. Granites petrology, structure, geological setting, and metallogeny

    Nédélec, Anne; Bowden, Peter

    2015-01-01

    Granites are emblematic rocks developed from a magma that crystallized in the Earth’s crust. They ultimately outcrop at the surface worldwide. This book, translated and updated from the original French edition Pétrologie des Granites (2011) is a modern presentation of granitic rocks from magma genesis to their crystallization at a higher level into the crust. Segregation from the source, magma ascent and shapes of granitic intrusions are also discussed, as well as the eventual formation of hybrid rocks by mingling/mixing processes and the thermomechanical aspects in country rocks around granite plutons. Modern techniques for structural studies of granites are detailed extensively. Granites are considered in their geological spatial and temporal frame, in relation with plate tectonics and Earth history from the Archaean eon. A chapter on granite metallogeny explains how elements of economic interest are concentrated during magma crystallization, and examples of Sn, Cu, F and U ore deposits are presented. Mi...

  5. A comparison study of single and double layer repositories for high level radioactive wastes within a saturated and discontinuous granitic rock mass

    Kim, Jhin Wung; Choi, Jong Won; Bae, Dae Suk

    2004-02-01

    The present study is to analyze and compare a long term thermohydro mechanical interaction behavior of a single layer and a double layer repository for high level radioactive wastes within a saturated and discontinuous granitic rock mass, and then to contribute this understanding to the development of a Korean disposal concept. The model includes a saturated and discontinuous granitic rock mass, PWR spent nuclear fuel in a disposal canister surrounded by compacted bentonite inside a deposition hole, and mixed bentonite backfilled in the rest of the space within a repository cavern. It is assumed that two joint sets exist within the model. Joint set 1 includes joints of 56 .deg. dip angle, spaced at 20 m, and joint set 2 is in the perpendicular direction to joint set 1 and includes joints of .deg. dip angle, spaced at 20 m. The two dimensional distinct element code, UDEC is used for the analysis. To understand the joint behavior adjacent to the repository cavern, Barton-Bandis joint model is used. Effect of the decay heat from PWR spent fuels on the repository model has been analyzed, and a steady state flow algorithm is used for the hydraulic analysis

  6. National survey of crystalline rocks and recommendations of regions to be explored for high-level radioactive waste repository sites

    Smedes, H.W.

    1983-04-01

    A reconnaissance of the geological literature on large regions of exposed crystalline rocks in the United States provides the basis for evaluating if any of those regions warrant further exploration toward identifying potential sites for development of a high-level radioactive waste repository. The reconnaissance does not serve as a detailed evaluation of regions or of any smaller subunits within the regions. Site performance criteria were selected and applied insofar as a national data base exists, and guidelines were adopted that relate the data to those criteria. The criteria include consideration of size, vertical movements, faulting, earthquakes, seismically induced ground motion, Quaternary volcanic rocks, mineral deposits, high-temperature convective ground-water systems, hydraulic gradients, and erosion. Brief summaries of each major region of exposed crystalline rock, and national maps of relevant data provided the means for applying the guidelines and for recommending regions for further study. It is concluded that there is a reasonable likelihood that geologically suitable repository sites exist in each of the major regions of crystalline rocks. The recommendation is made that further studies first be conducted of the Lake Superior, Northern Appalachian and Adirondack, and the Southern Appalachian Regions. It is believed that those regions could be explored more effectively and suitable sites probably could be found, characterized, verified, and licensed more readily there than in the other regions

  7. National survey of crystalline rocks and recommendations of regions to be explored for high-level radioactive waste repository sites

    Smedes, H.W.

    1983-04-01

    A reconnaissance of the geological literature on large regions of exposed crystalline rocks in the United States provides the basis for evaluating if any of those regions warrant further exploration toward identifying potential sites for development of a high-level radioactive waste repository. The reconnaissance does not serve as a detailed evaluation of regions or of any smaller subunits within the regions. Site performance criteria were selected and applied insofar as a national data base exists, and guidelines were adopted that relate the data to those criteria. The criteria include consideration of size, vertical movements, faulting, earthquakes, seismically induced ground motion, Quaternary volcanic rocks, mineral deposits, high-temperature convective ground-water systems, hydraulic gradients, and erosion. Brief summaries of each major region of exposed crystalline rock, and national maps of relevant data provided the means for applying the guidelines and for recommending regions for further study. It is concluded that there is a reasonable likelihood that geologically suitable repository sites exist in each of the major regions of crystalline rocks. The recommendation is made that further studies first be conducted of the Lake Superior, Northern Appalachian and Adirondack, and the Southern Appalachian Regions. It is believed that those regions could be explored more effectively and suitable sites probably could be found, characterized, verified, and licensed more readily there than in the other regions.

  8. Study on effects of coupled phenomenon on long-term behavior for crystalline rock. FY2015 (Contract research)

    Ichikawa, Yasuaki; Kimoto, Kazushi; Matsui, Hiroya; Kuwabara, Kazumichi; Ozaki, Yusuke

    2016-12-01

    It is important to evaluate the stability of a repository for high-level radioactive waste not only during the design, construction and operation phases, but also during the post-closure period, for time frames likely exceeding several millennia or longer. The rock mass around the tunnels could be deformed through time in response to time dependent behavior such as creep and stress relaxation. On the other hand, it was revealed that the chemical reaction of groundwater in a rock had an influence on the long-term behavior. An evaluation of the microcracks to have an influence on rock mechanical and chemical coupled phenomena is the issue the past long-term behavior for rock study. In fiscal year 2015, using a laser Doppler vibrometer that extends a frequency band up to 20 MHz, and measuring the surface wave transmitted through the granite specimens were estimated group velocity. As a result, group velocity until 100 kHz ∼ 500 kHz, revealed that tends to decrease while vibrating. Estimation of the group velocity from the group delay, by using the spatially averaged waveform has improved estimated frequency band and reliability. For this reason, the estimation of the group velocity from the group delay has also been shown to be easier than estimated by the wave number - frequency spectrum. As a result obtained, in the case of the modeling by the viscoelastic theory of the granite and a microcrack nondestructiveness evaluation, it is thought that it is useful information in the future. In order to use the knowledge of this study, there is a need to clarify the correspondence between the microscopic properties of the medium such as a crack and crystal grain and the change of the group velocity. (author)

  9. Interim guidelines on performance constraints for nuclear waste disposal in crystalline rock

    1984-01-01

    Performance constraint guidelines have been developed for geologic disposal of nuclear waste in crystalline rock. The approach taken in defining these guidelines was to consider the thermal, thermomechanical, and thermochemical behavior for three regions (very-near field, near field, and far field) of the repository during three time periods (operational, containment, and isolation) associated with the disposal system. Limits are proposed to ensure compliance with the current repository criteria proposed by the United States Nuclear Regulatory Commission (NRC) concerning repository siting and performance assessment. These criteria are: Substantial containment of all radionuclides within the waste package for a period of time between 300 and 1000 years after emplacement. Release rate after loss of containment of one part in 100,000 annually per radionuclide based on the nuclides inventory when the waste package is breached, and in situ ground-water transit time of 1000 years from the repository horizon to the accessible environment, compliance with the performance constraint guidelines presented herein will be required to ensure that the final repository design is in compliance with NRC criteria. The constraint guidelines have also been developed to satisfy the requirement for technical conservatism. 40 refs., 14 figs., 4 tabs

  10. Characterization of crystalline rocks in deep boreholes. The Kola, Krivoy Rog and Tyrnauz boreholes

    1992-12-01

    SKB studies, as one alternative, the feasibility of disposing of spent nuclear fuel in very deep boreholes. As a part of this work NEDRA has compiled geoscientific data from three superdeep boreholes within the former Soviet Union. The holes considered were: the Kola borehole, 12261 m deep and located on the Kola Peninsula, the Krivoy Rog borehole, 5000 m deep and located in Ukraine, and the Tyrnauz borehole, 4001 m deep and located between the Black Sea and the Caspian Sea. These boreholes all penetrate crystalline formations, but major differences are found when their tectonic environments are compared. Excluding the uppermost horizon affected by surface phenomena, data do not indicate any general correlation between depth and the state of rock fracturing, which is instead governed by site specific, lithological and tectonical factors. This applies also to fracture zones, which are found at similar frequencies at all depths. As opposed to the structural data, the hydrogeological and hydrochemical information reveals a vertical zonation, with clear similarities between the three boreholes. An upper zone with active circulation and fresh or slightly mineralized groundwaters reaches down 1000-2000 m. The interval from 1000-2000 m down to 4000-5000 m can be characterized as a transition zone with lower circulation rates and gradually increasing mineralisation. Below 4000-5000 m, strongly mineralized, stagnant, juvenile or metamorphogenic waters are found. Geothermal data verify the existence of this zonation. 28 figs, 30 tabs

  11. Groundwater flow into underground openings in fractured crystalline rocks: an interpretation based on long channels

    Black, John H.; Woodman, Nicholas D.; Barker, John A.

    2017-03-01

    Rethinking an old tracer experiment in fractured crystalline rock suggests a concept of groundwater flow in sparse networks of long channels that is supported by results from an innovative lattice network model. The model, HyperConv, can vary the mean length of `strings' of connected bonds, and the gaps between them, using two independent probability functions. It is found that networks of long channels are able to percolate at lower values of (bond) density than networks of short channels. A general relationship between mean channel length, mean gap length and probability of percolation has been developed which incorporates the well-established result for `classical' lattice network models as a special case. Using parameters appropriate to a 4-m diameter drift located 360 m below surface at Stripa Mine Underground Research Laboratory in Sweden, HyperConv is able to reproduce values of apparent positive skin, as observed in the so-called Macropermeability Experiment, but only when mean channel length exceeds 10 m. This implies that such channel systems must cross many fracture intersections without bifurcating. A general relationship in terms of flow dimension is suggested. Some initial investigations using HyperConv show that the commonly observed feature, `compartmentalization', only occurs when channel density is just above the percolation threshold. Such compartments have been observed at Kamaishi Experimental Mine (Japan) implying a sparse flow network. It is suggested that compartments and skin are observable in the field, indicate sparse channel systems, and could form part of site characterization for deep nuclear waste repositories.

  12. Excavation damage and disturbance in crystalline rock - results from experiments and analyses

    Baeckblom, Goeran

    2008-11-01

    -13 m/s to 10 -14 m/s. Excavation of the deposition tunnel using drill and blast would create much more widely dispersed damage (several tens of centimetres) than using a TBM (a few centimetres). A reasonable value for the hydraulic conductivity of the damage zone is 10 -8 m/s. This magnitude has been obtained during several tests in crystalline rocks, where excavation was of good quality and measured by integrating measurement under saturated conditions along the tunnel floor. Point observations of the hydraulic conductivity have provided both lower and higher individual results. This is due both to the natural variability of the rock properties as well as to the fact that damage is correlated to the amount of explosives, which varies along the periphery of the opening and also along the longitudinal section of the tunnel. The compilation in this report shows that spalling is the most important factor that will contribute to an extended axial transmissivity along a deposition tunnel. Measured hydraulic conductivity based on spalling in a test tunnel in crystalline rock at the AECL URL in Canada was in the order of 10 -6 m/s and significantly higher than the increased hydraulic conductivity due to the damage caused by the excavation process. Typical tests suggested within the area of the deposition holes are e.g.: - ultrasonic measurements; - testing of hydraulic transmissivity by multi-packers; - occasional laboratory tests on rock cores. To measure the connectivity of the excavation damaged zone, such tests can tentatively be made using ground penetrating radar. After backfilling a deposition tunnel, micro-seismics from neighbouring tunnels that have not yet been backfilled can be used to track the micro-seismic evolution after closure of the deposition tunnel

  13. An integrated approach to isotopic study of crystalline rock for a high-level waste repository: Area phase

    Gilbert, L.A.

    1986-01-01

    An integrated approach to assessing isotopic systems in crystalline rock is planned for area phase studies. This approach combines radiogenic isotope systems with petrography in order to characterize potential crystalline repository media. The coeval use of selected isotope systems will minimize the limitations of each method and provide intensive parameters yielding data on alteration timing, secondary mineral formation, temperature history, and radionuclide species migration. Isotope systems will be selected in order to measure differences in sensitivity to thermal disturbances and mobility due to fluid interaction. Comparative evaluation of isotope pair behavior may be used in combination with mineral versus whole-rock dates to provide data on heating and mobilization of alkali elements, lanthanides, and gases, caused by future introduction of waste

  14. The impact of a (hyper)alkaline plume on (fractured) crystalline rock

    Alexander, Russell

    2012-01-01

    Russell Alexander from Bedrock Geosciences, Switzerland, gave a presentation on the possible effects of cement pore waters on a crystalline host rock. Field, laboratory and natural analogue studies as well as geochemical modelling indicate that cement leachates tend to induce the sealing of fractures in the rock. These studies also indicate that strongly alkaline waters might: - Accelerate the dissolution of vitrified waste, but probably not affect the dissolution rate of spent fuel. - Degrade bentonite to some degree. To avoid some of the effects associated with the use of concrete, several approaches may be used: - Minimisation and tracking/monitoring of the concrete masses. - Development and use of low-pH cements and alternative grouting materials. - The selection of less fractured rock volumes for a repository location. The sealing of fractures evidenced in the Maquarin natural analogue study might contribute to limiting the extent of perturbations caused by an alkaline plume and is likely to create a hydraulic barrier that affects groundwater flow. The effects of these processes should be analysed in a safety case since they may support the idea of a self-sealing repository. Uncertainties in the treatment of an alkaline plume in fractured rock include: - The possible formation of colloids. - Thermodynamic data for cement components and secondary mineral stability. - Cement carbonation. - The effects of super-plasticisers. Given these uncertainties, current assessments of perturbations around a HLW or spent fuel repository caused by cementitious materials are often conservative and provide a pessimistic view of disposal system performance. Discussion of the paper included: Will groundwater flows in deep systems be fast enough to cause pervasive sealing of fractures? The process of how a network of fractures may be sealed over time is uncertain. The flow field will be altered as fractures are sealed and this may cause flow rates in other parts of the fracture

  15. Site-specific evaluation of safety issues for high-level waste disposal in crystalline rocks. Final report

    Jobmann, M. (ed.) [DBE Technology GmbH, Peine (Germany)

    2016-03-31

    In the past, German research and development (R and D) activities regarding the disposal of radioactive waste, including spent nuclear fuel, focused mainly on domal rock salt because rock salt was the preferred host rock formation. In addition, generic R and D work regarding alternative host rocks (crystalline rocks and claystones) had been performed as well for a long time but with lower intensity. Around the year 2000, as a consequence of the moratorium on the Gorleben site, the Federal Government decided to have argillaceous rocks and crystalline rocks investigated in more detail. As Germany does not have any underground research and host rock characterization facilities, international cooperation received a high priority in the German R and D programme for high-level waste (HLW) disposal in order to increase the knowledge regarding alternative host rocks. Major cornerstones of the cooperation are joint projects and experiments conducted especially in underground research laboratories (URL) in crystalline rocks at the Grimsel Test Site (Switzerland) and the Hard Rock Laboratory (HRL) Aespoe(Sweden) and in argillaceous rocks at the URL Mont Terri (Switzerland) and Bure (France). In 2001, the topic of radioactive waste disposal was integrated into the agreement between the former Russian Ministry of Atomic Energy (Minatom, now Rosatom) and the German Ministry of Labor (BMWA), now Ministry of Economic Affairs and Energy (BMWi), on cooperation regarding R and D on the peaceful utilization of nuclear power (agreement on ''Wirtschaftlich-Technische Zusammenarbeit'' WTZ). The intention was to have a new and interesting opportunity for international R and D cooperation regarding HLW disposal in crystalline rocks and the unique possibility to perform site-specific work, to test the safety demonstration tools available, and to expand the knowledge to all aspects specific to these host rocks. Another motivation for joining this cooperation was the

  16. Assessment of site-scale hydrogeological modelling possibilities in crystalline hard rock for safety appraisal

    Geier, J. [Cleanwater Hardrock Consulting, Corvallis, OR (United States); Luukkonen, A.

    2012-09-15

    This review describes the state-of-the-art in hydrogeological modelling for safety-case studies related to spent-fuel repositories in crystalline hard rock, focusing on issues of relevance for the KBS-3 disposal concept in Nordic environments. The review includes a survey of model capabilities and assumptions regarding groundwater flow processes, geological and excavation-related features, and boundary conditions for temperate, periglacial, and glacial climates. Modelling approaches are compared for research sites including the Stripa mine (Sweden), the Grimsel Test Site (Switzerland), the Whiteshell Underground Research Laboratory (Canada), the Aspo Hard Rock Laboratory and Simpevarp-Laxemar site (Sweden), the Forsmark site (Sweden), the Waste Isolation Pilot Plant site (USA), and Olkiluoto (Finland). Current hydrogeological models allow realistic representations, but are limited by availability of data to constrain their properties. Examples of calibrations of stochastic representations of heterogeneity are still scarce. Integrated models that couple flow and non-reactive transport are now well established, particularly those based on continuum representations. Models that include reactive transport are still mainly in the realm of research tools. Thus far, no single software tool allows fully coupled treatment of all relevant thermal, hydraulic, mechanical, and chemical transport processes in the bedrock, together with climate-related physical processes at the ground surface, and with explicit treatment of bedrock heterogeneity. Hence practical applications require combinations of models based on different simplifications. Key improvements can be expected in treatment of the unsaturated zone, simulation of heterogeneous infiltration at the surface, and hydromechanical coupling. Significant advances have already been made in the amounts and types of data that can be used in site-scale models, including large datasets to define topography and other surface

  17. Verification of the both hydrogeological and hydrogeochemical code results by an on-site test in granitic rocks

    Michal Polák

    2007-01-01

    Full Text Available The project entitled “Methods and tools for the evaluation of the effect of engeneered barriers on distant interactions in the environment of a deep repository facility” deals with the ability to validate the behavior of applied engeneered barriers on hydrodynamic and migration parameters in the water-bearing granite environment of a radioactive waste deep repository facility. A part of the project represents a detailed mapping of the fracture network by means of geophysical and drilling surveys on the test-site (active granite quarry, construction of model objects (about 100 samples with the shape of cylinders, ridges and blocks, and the mineralogical, petrological and geochemical description of granite. All the model objects were subjected to migration and hydrodynamic tests with the use of fluorescein and NaCl as tracers. The tests were performed on samples with simple fractures, injected fractures and with an undisturbed integrity (verified by ultrasonic. The gained hydrodynamic and migration parameters of the model objects were processed with the modeling software NAPSAC and FEFLOW. During the following two years, these results and parameters will be verified (on the test-site by means of a long-term field test including the tuning of the software functionality.

  18. A simplified fracture network model for studying the efficiency of a single well semi open loop heat exchanger in fractured crystalline rock

    de La Bernardie, Jérôme; de Dreuzy, Jean-Raynald; Bour, Olivier; Thierion, Charlotte; Ausseur, Jean-Yves; Lesuer, Hervé; Le Borgne, Tanguy

    2016-04-01

    Geothermal energy is a renewable energy source particularly attractive due to associated low greenhouse gas emission rates. Crystalline rocks are in general considered of poor interest for geothermal applications at shallow depths (structure, heat exchanges and storage may be highlighted.

  19. Analysis of Precursors Prior to Rock Burst in Granite Tunnel Using Acoustic Emission and Far Infrared Monitoring

    Zhengzhao Liang

    2013-01-01

    Full Text Available To understand the physical mechanism of the anomalous behaviors observed prior to rock burst, the acoustic emission (AE and far infrared (FIR techniques were applied to monitor the progressive failure of a rock tunnel model subjected to biaxial stresses. Images of fracturing process, temperature changes of the tunnel, and spatiotemporal serials of acoustic emission were simultaneously recorded during deformation of the model. The b-value derived from the amplitude distribution data of AE was calculated to predict the tunnel rock burst. The results showed that the vertical stress enhanced the stability of the tunnel, and the tunnels with higher confining pressure demonstrated a more abrupt and strong rock burst. Abnormal temperature changes around the wall were observed prior to the rock burst of the tunnel. Analysis of the AE events showed that a sudden drop and then a quiet period could be considered as the precursors to forecast the rock burst hazard. Statistical analysis indicated that rock fragment spalling occurred earlier than the abnormal temperature changes, and the abnormal temperature occurred earlier than the descent of the AE b-value. The analysis indicated that the temperature changes were more sensitive than the AE b-value changes to predict the tunnel rock bursts.

  20. Catchment-wide weathering and erosion rates of mafic, ultramafic, and granitic rock from cosmogenic meteoric 10Be/9Be ratios

    Dannhaus, N.; Wittmann, H.; Krám, P.; Christl, M.; von Blanckenburg, F.

    2018-02-01

    Quantifying rates of weathering and erosion of mafic rocks is essential for estimating changes to the oceans alkalinity budget that plays a significant role in regulating atmospheric CO2 levels. In this study, we present catchment-wide rates of weathering, erosion, and denudation measured with cosmogenic nuclides in mafic and ultramafic rock. We use the ratio of the meteoric cosmogenic nuclide 10Be, deposited from the atmosphere onto the weathering zone, to stable 9Be, a trace metal released by silicate weathering. We tested this approach in stream sediment and water from three upland forested catchments in the north-west Czech Republic. The catchments are underlain by felsic (granite), mafic (amphibolite) and ultramafic (serpentinite) lithologies. Due to acid rain deposition in the 20th century, the waters in the granite catchment exhibit acidic pH, whereas waters in the mafic catchments exhibit neutral to alkaline pH values due to their acid buffering capability. The atmospheric depositional 10Be flux is estimated to be balanced with the streams' dissolved and particulate meteoric 10Be export flux to within a factor of two. We suggest a correlation method to derive bedrock Be concentrations, required as an input parameter, which are highly heterogeneous in these small catchments. Derived Earth surface metrics comprise (1) Denudation rates calculated from the 10Be/9Be ratio of the "reactive" Be (meaning sorbed to mineral surfaces) range between 110 and 185 t km-2 y-1 (40 and 70 mm ky-1). These rates are similar to denudation rates we obtained from in situ-cosmogenic 10Be in quartz minerals present in the bedrock or in quartz veins in the felsic and the mafic catchment. (2) The degree of weathering, calculated from the fraction of 9Be released from primary minerals as a new proxy, is about 40-50% in the mafic catchments, and 10% in the granitic catchment. Lastly, (3) erosion rates were calculated from 10Be concentrations in river sediment and corrected for sorting

  1. 1{sup st} workshop proceedings of the collaborative project ''Crystalline rock retention processes'' (7th EC FP CP CROCK)

    Rabung, Thomas; Molinero, Jorge; Garcia, David; Montoya, Vanessa (eds.)

    2012-07-01

    The EURATOM 7th EC Framework Program Collaborative Project Crystalline ROCK retention processes (CROCK) started in January 2011 and extends over 2 and a half years. The key driver for initiation the CP CROCK, identified by national Waste Management Organizations, is the undesired high uncertainty and the associated conservatism with respect to the radionuclide transport in the crystalline host-rock far-field around geological disposal of high-level radioactive wastes.

  2. Fluid flow in crystalline rocks: Relationships between groundwater spring alignments and other surface lineations at Altnabreac, United Kingdom

    Brereton, N.R.; McEwen, T.J.; Lee, M.K.

    1987-01-01

    The Strath Halladale Granite in the region around Altnabreac, northern Scotland, United Kingdom, has been studied with a view to establishing a relationship between the regional distribution of faults and fracture zones, surface discharges of groundwater, and groundwater flow systems. A major component of the groundwater flow is through the rock fractures. Because of the extensive superficial cover the surface expression of major fractures was difficult to identify from the limited surface exposures. Geophysical surveys and aerial photography enabled the authors to define lineations which could be related to the presence of fractures. The areal distribution of groundwater spring discharges was mapped using thermal infrared line scan techniques. The distribution of these springs has been studied to assess their relationships to surface lineaments and to correlations with geophysical and fracture mapping data. copyright American Geophysical Union 1987

  3. Recent progress of the NEA Stripa project on in situ experiments in granite associated with the disposal of radioactive waste

    Carlyle, S.G.; Carlsson, H.S.

    1987-01-01

    The NEA Stripa project has devoted considerable effort to the measurement and assessment of the hydrogeology, hydrogeochemistry and migration phenomena of the stripa granite and to the simulation of conditions likely to be found within an engineered repository in granitic rock. These include refining existing, and developing new, geophysical and hydraulic techniques for the mapping and characterization of fractures in crystalline rocks; conducting field experiments to assess the migration of tracers in single-and multiple-fracture systems; and studying the behaviour of bentonite clay as the back-filling and sealing material in a granitic environment. This paper summarizes the most important findings and outlines the main aims of possible future research under any phase 3 of the project. The latter may include making mathematical predictions of the hydrogeological behavior of the Stripa granite and their subsequent validation by field measurements

  4. Drip Sealing Grouting of Tunnels in Crystalline Rock: Conceptualisation and Technical Strategies

    Butron, Christian

    2012-07-01

    A conceptual model of the groundwater hydraulic conditions around the tunnel contour in ancient brittle crystalline rocks has been developed and verified. The general aim has been to reach an understanding of the groundwater conditions in and close to the tunnel roof where dripping takes place and to propose technical and practical strategies for waterproofing. Dripping is accompanied by ice growth and icicle formation in cold regions, creating additional problems such as shotcrete fall-outs, icicle fall-outs, damage to vehicles, damage to trains, etc. The methodology for the development of the conceptual model is based mainly on transmissivity determinations from short-duration hydraulic tests and analyses of the connectivity of the fracture structure by means of semi-variogram analysis. The determination of the dimensionality of the flow in the fractures has also been found to be essential in order to describe the conductive system. This conceptual model describes the fracture systems as a combination of transmissive patches (2D-flow fractures) connected by less pervious channels (1D-flow fractures). It provides an understanding of the heterogeneity and connectivity of the fracture network and thus the groundwater conditions, not only in the roof but also around the tunnel contour. The pre-excavation grouting design process used in the tunnelling projects followed a structured approach and the evaluation showed that the grouting design reduced the inflow and fulfilled the environmental demands. However, dripping remained, making its characterisation very important when proposing a possible solution for its control. It is proposed that the remaining dripping comes from a channelised system that has been left unsealed and which would be extremely difficult to intersect with future boreholes, as well as from some ungrouted fractures with inconvenient orientations. Geomembrane lining and post-excavation grouting are possible solutions, although particular attention

  5. Excavation damage and disturbance in crystalline rock - results from experiments and analyses

    Baeckblom, Goeran (Conrox AB, Stockholm (Sweden))

    2008-11-15

    periphery, 2x10-11 m/s at a depth of 5 mm, and 10-13 m/s at a distance of 30 mm from the tunnel wall. The virgin crystal matrix of the rock is in the range of 10-13 m/s to 10-14 m/s. Excavation of the deposition tunnel using drill and blast would create much more widely dispersed damage (several tens of centimetres) than using a TBM (a few centimetres). A reasonable value for the hydraulic conductivity of the damage zone is 10-8 m/s. This magnitude has been obtained during several tests in crystalline rocks, where excavation was of good quality and measured by integrating measurement under saturated conditions along the tunnel floor. Point observations of the hydraulic conductivity have provided both lower and higher individual results. This is due both to the natural variability of the rock properties as well as to the fact that damage is correlated to the amount of explosives, which varies along the periphery of the opening and also along the longitudinal section of the tunnel.

  6. Analysis of Precursors Prior to Rock Burst in Granite Tunnel Using Acoustic Emission and Far Infrared Monitoring

    Liang, Zhengzhao; Liu, Xiangxin; Zhang, Yanbo; Tang, Chunan

    2013-01-01

    To understand the physical mechanism of the anomalous behaviors observed prior to rock burst, the acoustic emission (AE) and far infrared (FIR) techniques were applied to monitor the progressive failure of a rock tunnel model subjected to biaxial stresses. Images of fracturing process, temperature changes of the tunnel, and spatiotemporal serials of acoustic emission were simultaneously recorded during deformation of the model. The b-value derived from the amplitude distribution data of AE wa...

  7. Determination of radioactive materials in granite used as ornamental rocks; Determinacao de materiais radioativos em granitos utilizados como rochas ornamentais

    Salas, Humberto Terrazas; Barbosa, Joao Batista Santos; Murta, Clecio Campi; Rocha, Francisco de Assis [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)). E-mail: salasht@urano.cdtn.br; Nalini Junior, Herminio Arias; Mendes, Julio Cesar [Ouro Preto Univ., MG (Brazil). Escola de Minas. Dept. de Geologia

    2000-07-01

    For environment quality control, either in a global or regional perspective, the determination of the radioactivity present in the minerals of rocks must be included. This control is carried out through specific analysis, applied to all geological materials used in civil architecture design and other applications (e.g. artistic). To date, the radioactivity of rocks has not been specifically studied, from which an adequate and comprehensive systematics is applied, in order to determine the radioactive minerals and their corresponding alterations. In Brazil, the industry of ornamental rocks is continually increasing at high rates, with a growing variety of rocks being commercialized locally as well as abroad. To a certain extent, the technical characterization of these rocks, through standard procedures defined by standardization institutions, is already available worldwide. However, among the petrographic properties specified for these rocks, minor or accessory minerals (less than 1%) are not adequately determined and detected. Among these components are radioactive minerals and, occasionally, carriers of precious metals, rare earths and other economically important minerals. (author)

  8. Rock Magnetic Study of IODP/ICDP Expedition 364 Site M0077A Drill Cores: Post-Impact Sediments, Impact Breccias, Melt, Granitic Basement and Dikes

    Fucugauchi, J. U.; Perez-Cruz, L. L.; Rebolledo-Vieyra, M.; Tikoo, S.; Zylberman, W.; Lofi, J.

    2017-12-01

    Drilling at Site M0077 sampled post-impact sediments overlying a peak ring consisting of impact breccias, melt rock and granitoids. Here we focus on characterizing the peak ring using magnetic properties, which vary widely and depend on mineralogy, depositional and emplacement conditions and secondary alterations. Rock magnetic properties are integrated with Multi-Sensor Core Logger (MSCL) data, vertical seismic profile, physical properties, petrographic and chemical analyses and geophysical models. We measure low-field magnetic susceptibility at low- and high-frequencies, intensity and direction of natural remanent magnetization (NRM) and laboratory-induced isothermal (IRM) and anhysteretic (ARM) magnetizations, alternating-field demagnetization of NRM, IRM and NRM, susceptibility variation with temperature, anisotropy of magnetic susceptibility, hysteresis and IRM back-field demagnetization. Post-impact carbonates show low susceptibilities and NRM intensities, variable frequency-dependent susceptibilities and multivectorial remanences residing in low and high coercivity minerals. Hysteresis loops show low coercivity saturation magnetizations and variable paramagnetic mineral contents. Impact breccias (suevites) and melt rock show higher susceptibilities, low frequency-dependent susceptibilities, high NRM, ARM and IRM intensities and moderate ARM intensity/susceptibility ratios. Magnetic signal is dominated by fine-grained magnetite and titanomagnetites with PSD domain states. Melt rocks at the base of impactite section show the highest susceptibilities and remanence intensities. Basement section is characterized by low susceptibilities in the granites and higher values in the dikes, with NRM and ARM intensities increasing towards the base. The high susceptibilities and remanence intensities correlate with high seismic velocities, density and decreased porosity and electrical resistivity. Fracturing and alteration account for the reduced seismic velocities

  9. Data and uncertainty assessment for radionuclide K{sub d} partitioning coefficients in granitic rock for use in SR-Can calculations

    Crawford, James; Neretnieks, Ivars; Malmstroem, Maria [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Chemical Engineering and Technology

    2006-10-15

    SKB is currently preparing licence applications related to the proposed deep repository for spent nuclear fuel as well as the encapsulation plant required for canister fabrication. The present report is one of several specific data reports that form the data input to an interim safety report (SR-Can) for the encapsulation plant licence application. This report concerns the derivation and recommendation of generic K{sub d} data (i.e. linear partitioning coefficients) for safety assessment modelling of far-field radionuclide transport in fractured granitic rock. The data are derived for typical Swedish groundwater conditions and rock types distinctive of those found on the Simpevarp peninsula and Forsmark. Data have been derived for 8 main elements (Cs, Sr, Ra, Ni, Th, U, Np, Am) and various oxidation states. The data have also been supplied with tentative correction factors to account for artefacts that have not been previously considered in detail in previous compilations. For the main reviewed solutes the data are given in terms of a best estimate K{sub d} value assumed to be the median of the aggregate set of selected data. A range corresponding to the 25-75% inter-quartile range is also specified and probable ranges of uncertainty are estimated in the form of an upper and lower limit to the expected variability. Data for an additional 19 elements that have not been reviewed are taken from a previous compilation by Carbol and Engkvist.

  10. Granite disposal of U.S. high-level radioactive waste.

    Freeze, Geoffrey A.; Mariner, Paul E.; Lee, Joon H.; Hardin, Ernest L.; Goldstein, Barry; Hansen, Francis D.; Price, Ronald H.; Lord, Anna Snider

    2011-08-01

    This report evaluates the feasibility of disposing U.S. high-level radioactive waste in granite several hundred meters below the surface of the earth. The U.S. has many granite formations with positive attributes for permanent disposal. Similar crystalline formations have been extensively studied by international programs, two of which, in Sweden and Finland, are the host rocks of submitted or imminent repository license applications. This report is enabled by the advanced work of the international community to establish functional and operational requirements for disposal of a range of waste forms in granite media. In this report we develop scoping performance analyses, based on the applicable features, events, and processes (FEPs) identified by international investigators, to support generic conclusions regarding post-closure safety. Unlike the safety analyses for disposal in salt, shale/clay, or deep boreholes, the safety analysis for a mined granite repository depends largely on waste package preservation. In crystalline rock, waste packages are preserved by the high mechanical stability of the excavations, the diffusive barrier of the buffer, and favorable chemical conditions. The buffer is preserved by low groundwater fluxes, favorable chemical conditions, backfill, and the rigid confines of the host rock. An added advantage of a mined granite repository is that waste packages would be fairly easy to retrieve, should retrievability be an important objective. The results of the safety analyses performed in this study are consistent with the results of comprehensive safety assessments performed for sites in Sweden, Finland, and Canada. They indicate that a granite repository would satisfy established safety criteria and suggest that a small number of FEPs would largely control the release and transport of radionuclides. In the event the U.S. decides to pursue a potential repository in granite, a detailed evaluation of these FEPs would be needed to inform site

  11. Building the safety case for a hypothetical underground repository in crystalline rock. Final report. Vol. 2. Safety file

    Biurrun, E.; Engelmann, H.J.; Jobmann, M.; Lommerzheim, A.; Popp, W.; Frentz, R.R. v.; Wahl, A.

    1996-10-01

    The study was intended as a desk simulation of the process of preparing a licensing application for a deep repository for spent fuel and high level waste in crystalline rock. After clarifying of organizational aspects of table of contents specifying all aspects in a safety life for license application were considered. The volume II is subdivided in two parts. Part A describes the general information, waste description, site characteristics, disposal facility design, reporitory construction and operation, quality assurance, operational safety, repository closure, organization and financial aspects, and long-term safety assessment. Part B deals with the impact of retrievability. (DG)

  12. Results of isotopic geochemical and mineralogical investigations of crystalline rocks of the Carpathian Massif in 1973-1975

    Shcherbak, N.P.; Bartnitskij, E.N.; Eliseeva, G.D.

    1979-01-01

    The most frequent accesory mineral in crystalline rocks in the Czechoslovak and Ukrainian Carpathians is zircon, the least frequent is monazite. The differences are described in the mineralogical properties of zircon of different origin. For dating volcanism, the content and the isotope composition was determined of U and Pb in zircon and of U, Pb and Th in monazite. The earliest volcanic processes occurred in the Eastern Carpathians approximately 600 to 640 million years ago, in the Western Carpathians approximately 400 million years ago. (Ha)

  13. Geotechnical assessment and instrumentation needs for nuclear waste isolation in crystalline and argillaceous rocks

    1979-01-01

    To evaluate the state-of-the-art, research needs, and research priorities related to waste disposal in largely impermeable rocks, scientists and engineers working on geologic aspects of nuclear waste disposal were brought together. This report and recommendations are the proceedings from that symposium. Three panels were organized on rock properties, fracture hydrology, and geochemistry. Panel discussions and recommendations are presented

  14. Characterizing and modelling the excavation damaged zone (EDZ) in crystalline rock in the context of radioactive waste disposal

    Hudson, J.A.; Backstrom, A.; Rutqvist, J.; Jing, L.; Backers, T.; Chijimatsu, M.; Christiansson, R.; Feng, X.-T.; Kobayashi, A.; Koyama, T.; Lee, H.-S.; Neretnieks, I.; Pan, P.Z.; Rinne, M.; Shen, B.-T.

    2008-01-01

    This paper describes current knowledge about the nature of and potential for thermo-hydro-mechanical-chemical modelling of the Excavation Damaged Zone (EDZ) around the excavations for an underground radioactive waste repository. In the first part of the paper, the disturbances associated with excavation are explained, together with reviews of Workshops that have been held on the subject. In the second part of the paper, the results of a DECOVALEX research programme on modelling the EDZ are presented. Four research teams used four different models to simulate the complete stress-strain curve for Avro granite from the Swedish Aespoe Hard Rock Laboratory. Subsequent research extended the work to computer simulation of the evolution of the repository using a 'wall block model' and a 'near-field model'. This included assessing the evolution of stress, failure and permeability and time dependent effects during repository evolution. As discussed, all the computer models are well suited to sensitivity studies for evaluating the influence of their respective supporting parameters on the complete stress-strain curve for rock and for modelling the EDZ

  15. The crystalline basement of Estonia: rock complexes of the Palaeoproterozoic Orosirian and Statherian and Mesoproterozoic Calymmian periods, and regional correlations

    Kirs, Juho

    2009-12-01

    Full Text Available New data on the Fennoscandian Shield and the Baltic area suggest a need for reinterpretation of the stratigraphy of Estonian Precambrian rock complexes. The rocks of the Tallinn Zone formed in the framework of the Fennian orogeny at the margin of the Bergslagen microcontinent 1.90–1.88 Ga ago. The precise age of the Alutaguse Zone is not known. It may have formed either during the 1.93–1.91 Ga Lapland–Savo orogeny or as a rifted eastern part of the Tallinn Zone in the Fennian orogeny. The granulites of western and southern Estonia belong to the volcanic arcs inside the 1.84–1.80 Ga Svecobaltic orogenic belt and show peak metamorphic conditions of 1.78 Ga. Small shoshonitic plutons formed 1.83–1.63 Ga, the small granitic plutons of the Wiborg Rapakivi Subprovince 1.67–1.62 Ga, and the Riga pluton 1.59–1.54 Ga ago.

  16. Characterising and modelling the excavation damaged zone (EDZ) in crystalline rock in the context of radioactive waste disposal

    Hudson, J.A.; Backstrom, A.; Rutqvist, J.; Jing, L.; Backers, T.; Chijimatsu, M.; Christiansson, R.; Feng, X.-T.; Kobayashi, A.; Koyama, T.; Lee, H.-S.; Neretnieks, I.; Pan, P.Z.; Rinne, M.; Shen, B.-T.

    2008-10-01

    This paper describes current knowledge about the nature of and potential for thermo-hydro-mechanical-chemical modelling of the Excavation Damaged Zone (EDZ) around the excavations for an underground radioactive waste repository. In the first part of the paper, the disturbances associated with excavation are explained, together with reviews of Workshops that have been held on the subject. In the second part of the paper, the results of a DECOVALEX research programme on modelling the EDZ are presented. Four research teams used four different models to simulate the complete stress-strain curve for Avro granite from the Swedish Aespoe Hard Rock Laboratory. Subsequent research extended the work to computer simulation of the evolution of the repository using a 'wall block model' and a 'near-field model'. This included assessing the evolution of stress, failure and permeability and time dependent effects during repository evolution. As discussed, all the computer models are well suited to sensitivity studies for evaluating the influence of their respective supporting parameters on the complete stress-strain curve for rock and for modelling the EDZ.

  17. Chemistry and origin of deep ground water in crystalline rocks; Kemi och genes av djupa grundvatten i kristallint berg

    Lagerblad, B [Swedish Cement and Concrete Research Inst., Stockholm (Sweden)

    1995-11-01

    This report discusses the interactions between water and crystalline rocks and its consequences for the chemical composition of the water. It also treats how flows of different types of water are modified by the rock, and the possible consequences for the ground water near a nuclear waste repository. The focus of the work is the changes in composition that ground water gets at deep levels in the rock. Data from Finnsjoen and Aespoe in Sweden show higher salinity in deep rock, which has been interpreted as a result of marine inflow of water during glaciation. Data from other, deeper boreholes in Finland, Canada, Russia, England and Sweden show that the increasing salinity is a rule and very high at great depths, higher than marine water can produce. Therefore, the deep waters from Finnsjoen and Aespoe are probably very old, and the high salinity a result from geological processes. Differing cation and isotopic composition than seawater also indicate geologic water. Differing theories on the origin of the ground water should be regarded in the safety analysis for a repository. 36 refs, 3 figs, 1 tab.

  18. Controls on Weathering of Pyrrhotite in a Low-Sulfide, Granitic Mine-Waste Rock in the Canadian Arctic

    Langman, J. B.; Holland, S.; Sinclair, S.; Blowes, D.

    2013-12-01

    Increased environmental risk is incurred with expansion of mineral extraction in the Arctic. A greater understanding of geochemical processes associated with hard-rock mining in this cold climate is needed to evaluate and mitigate these risks. A laboratory and in-situ experiment was conducted to examine mineral weathering and the generation of acid rock drainage in a low-sulfide, run-of-mine waste rock in an Arctic climate. Rock with different concentrations of sulfides (primarily pyrrhotite [Fe7S8] containing small amounts of Co and Ni) and carbonates were weathered in the laboratory and in-situ, large-scale test piles to examine leachate composition and mineral weathering. The relatively larger sulfide-containing rock produced sufficient acid to overcome carbonate buffering and produced a declining pH environment with concomitant release of SO4, Fe, Co, and Ni. Following carbonate consumption, aluminosilicate buffering stabilized the pH above 4 until a reduction in acid generation. Results from the laboratory experiment assisted in determining that after consumption of 1.6 percent of the total sulfide, the larger sulfide-concentration test pile likely is at an internal steady-state or maximal weathering rate after seven years of precipitation input and weathering that is controlled by an annual freeze-thaw cycle. Further weathering of the test pile should be driven by external factors of temperature and precipitation in this Arctic, semi-arid region instead of internal factors of wetting and non-equilibrium buffering. It is predicted that maximal weathering will continue until at least 20 percent of the total sulfide is consumed. Using the identified evolution of sulfide consumption in this Arctic climate, a variable rate factor can now be assessed for the possible early evolution and maximal weathering of larger scale waste-rock piles and seasonal differences because of changes in the volume of a waste-rock pile undergoing active weathering due to the freeze

  19. Hydrogeologic controls on induced seismicity in crystalline basement rocks due to fluid injection into basal reservoirs.

    Zhang, Yipeng; Person, Mark; Rupp, John; Ellett, Kevin; Celia, Michael A; Gable, Carl W; Bowen, Brenda; Evans, James; Bandilla, Karl; Mozley, Peter; Dewers, Thomas; Elliot, Thomas

    2013-01-01

    A series of Mb 3.8-5.5 induced seismic events in the midcontinent region, United States, resulted from injection of fluid either into a basal sedimentary reservoir with no underlying confining unit or directly into the underlying crystalline basement complex. The earthquakes probably occurred along faults that were likely critically stressed within the crystalline basement. These faults were located at a considerable distance (up to 10 km) from the injection wells and head increases at the hypocenters were likely relatively small (∼70-150 m). We present a suite of simulations that use a simple hydrogeologic-geomechanical model to assess what hydrogeologic conditions promote or deter induced seismic events within the crystalline basement across the midcontinent. The presence of a confining unit beneath the injection reservoir horizon had the single largest effect in preventing induced seismicity within the underlying crystalline basement. For a crystalline basement having a permeability of 2 × 10(-17)  m(2) and specific storage coefficient of 10(-7) /m, injection at a rate of 5455 m(3) /d into the basal aquifer with no underlying basal seal over 10 years resulted in probable brittle failure to depths of about 0.6 km below the injection reservoir. Including a permeable (kz  = 10(-13)  m(2) ) Precambrian normal fault, located 20 m from the injection well, increased the depth of the failure region below the reservoir to 3 km. For a large permeability contrast between a Precambrian thrust fault (10(-12)  m(2) ) and the surrounding crystalline basement (10(-18)  m(2) ), the failure region can extend laterally 10 km away from the injection well. © 2013, National Ground Water Association.

  20. Migration of fluids as a tool to evaluate the feasibility of the implantation of geological radioactive wastes repositories (RARN) in granitoid rocks: tests on granites submitted to natural deformation vs. not deformed

    Lopes, Nilo Henrique Balzani; Barbosa, Pedro Henrique Silva; Santos, Alanna Leite dos; Amorim, Lucas Eustáquio Dias; Freitas, Mônica Elizetti de; Rios, Francisco Javier

    2017-01-01

    Fluid composition and migration studies in granitoid rocks subjected to deformation events are a factor that should be considered in the selection of geologically favorable areas for RANR construction, and may be an excellent complement to engineering barrier designs. The research objective was to develop an academic approach, comparing the behavior of deformed and non-deformed granites, not being related to any CNEN project of deploying repositories. It is concluded that in the choice of suitable sites for the construction of repositories, granite bodies that are submitted to metamorphic / deformation / hydrothermal events or that are very fractured should be disregarded. The domes of granite batholith that have undergone hydraulic billing should also be discarded. It has been found that, because of the warming caused by radioactive decay reactions, there is a real possibility that the release of potentially abrasive fluids contained in the minerals can reach and corrode the walls of the repositories and / or packaging

  1. Preliminary evaluation of 30 potential granitic rock sites for a radioactive waste storage facility in southern Nevada

    Boardman, C.R.; Knutson, C.F.

    1978-02-15

    Results of preliminary study are presented which was performed under subtask 2.7 of the NTS Terminal Waste Storage Program Plan for 1978. Subtask 2.7 examines the feasibility of locating a nuclear waste repository in a granitic stock or pluton in southern Nevada near the Nevada Test Site (NTS). It is assumed for the purposes of this study that such a repository cannot be located at NTS. This assumption may or may not be correct. This preliminary report does not identify a particular site as being a suitable location for a repository. Nor does it absolutely eliminate a particular site from further consideration. It does, however, answer the basic question of probable suitability of some of the sites and present a systematic method for site evaluation. Since the findings of this initial study have been favorable, it will be followed by more exhaustive and detailed studies of the original 30 sites and perhaps others. In future studies some of the evaluation criteria used in the preliminary study may be modified or eliminated, and new criteria may be introduced.

  2. Preliminary evaluation of 30 potential granitic rock sites for a radioactive waste storage facility in southern Nevada

    Boardman, C.R.; Knutson, C.F.

    1978-01-01

    Results of preliminary study are presented which was performed under subtask 2.7 of the NTS Terminal Waste Storage Program Plan for 1978. Subtask 2.7 examines the feasibility of locating a nuclear waste repository in a granitic stock or pluton in southern Nevada near the Nevada Test Site (NTS). It is assumed for the purposes of this study that such a repository cannot be located at NTS. This assumption may or may not be correct. This preliminary report does not identify a particular site as being a suitable location for a repository. Nor does it absolutely eliminate a particular site from further consideration. It does, however, answer the basic question of probable suitability of some of the sites and present a systematic method for site evaluation. Since the findings of this initial study have been favorable, it will be followed by more exhaustive and detailed studies of the original 30 sites and perhaps others. In future studies some of the evaluation criteria used in the preliminary study may be modified or eliminated, and new criteria may be introduced

  3. Study on crystalline rock aiming at evaluation method of long-term behavior of rock mass (Joint research)

    Fukui, Katsunori; Hashiba, Kimihiro; Matsui, Hiroya

    2017-11-01

    It is important to evaluate the stability of a repository for high-level radioactive waste not only during the design, construction and operation phases, but also during the post-closure period, for time frames likely exceeding several millennia or longer. The rock mass around the tunnels could be deformed through time in response to time dependent behavior such as creep and stress relaxation. Therefore, development of methodology to evaluate the past long-term behavior of rock mass is considered to be an issue. In view of above points, this study has been started as a collaboration study with the University of Tokyo from Fiscal Year 2016. In FY 2016, creep testing on Tage tuff was continuously conducted. Existing theory of rate process and stochastic process was modified to be applied to evaluate effects of water, and then the modified theory was validated based on the results of strength and creep tests performed under dry and wet conditions. Furthermore, effects of water contents on stress-strain curves were examined by uniaxial compression testing under various water content conditions. (author)

  4. Geochronology (Rb-Sr, Sm-Nd and Pb-Pb) of the proterozoic granulitic and granitic rocks around Usilampatti, Madurai district, Tamil Nadu: implication on age of various lithounits

    Pandey, U.K.; Pandey, B.K.; Krishnamurthy, P.

    2005-01-01

    Rb-Sr, Sm-Nd and Pb-Pb systematics on mafic granulites, intermediate- charnockites, charnockites, calc-granulites, orthogneisses, leptynites, granites and two (2) mineral samples (microcline and muscovite) from pegmatite have been studied. Sm-Nd model ages (T DM ) for most of the rocks cluster around 2.1 Ga. Calc-granulites gave Rb-Sr whole rock isochron age of 1339 ± 110 Ma with initial 87 Sr/ 86 Sr ratio (I.R.) = 0.709. Mesoproterozoic age for the Metasedimentary Group of rocks (calc-granulites) has been inferred based on their 87 Sr/ 86 Sr ratio also. Granites and leptynites have yielded Rb-Sr whole rock isochron ages of 823± 38 Ma, with I.R. = 0.713 and 894± 82 Ma, with I.R. = 0.708 respectively which are younger than the calc-granulites. Microcline and muscovite from pegmatite gave Rb-Sr model ages as 532 and 491 Ma respectively. Granites, leptynites and calc-granulites are derived from the crustal source as indicated by their high initial 87 Sr/ 86 Sr ratios. Most probably the protolith of the granitic and granulitic rocks is of Palaeoproterozoic age in this part of the Madurai Block. The minimum age of granulite grade of metamorphism has been inferred at c. 850 Ma, indirectly on the basis of Rb-Sr ages of leptynites, which normally form during the evolution of granulite facies assemblages. Both granulite facies metamorphism and granitic magmatism probably took place during Neoproterozoic period correlatable to the early phase of Pan-African orogeny. Later decompression, causing mineral scale resetting of the Rb-Sr and Sm-Nd systematics, around 450-550 Ma, may correspond to the final exhumation, which brought the middle to lower crustal granulites to upper crustal levels, during the last phase of Pan-African activity. As per ages obtained on various lithounits in the present study the Metasedimentary Group of rocks (Mesoproterozoic) are younger than the Charnockite Group of rocks (Palaeoproterozoic) followed by the rocks belonging to the Migmatite Complex

  5. Geochronology (Rb-Sr, Sm-Nd and Pb-Pb) of the proterozoic granulitic and granitic rocks around Usilampatti, Madurai District, Tamil Nadu: implication on age of various lithounits

    Pandey, U.K.; Pandey, B.K.; Krishnamurthy, P.

    2005-01-01

    Rb-Sr, Sm-Nd and Pb-Pb systematics on mafic granulites, intermediate-charnockites, charnockites, calc- granulites, orthogneisses, leptynites, granites and two (2) mineral samples (microcline and muscovite) from pegmatite have been studied. Sm-Nd model ages (T DM ) for most of the rocks cluster around 2.1 Ga. Calc-granulites gave Rb-Sr whole rock isochron age of 1339± 110 Ma with initial 87 Sr/ 86 Sr ratio (IR)= 0.709. Mesoproterozoic age for the metasedimentary group of rocks (calc-granulites) has been inferred based on their 86 Sr/ 86 Sr ratio also. Granites and leptynites have yielded Rb-Sr whole rock isochron ages of 823 ± 38 Ma, with I.R. = 0.713 and 894± 82 Ma, with I.R.= 0.708 respectively which are younger than the calc-granulites. Microcline and muscovite from pegmatite gave Rb-Sr model ages as 532 and 491 Ma respectively. Granites, leptynites and calc-granulites are derived from the crustal source as indicated by their high initial 87 Sr/ 86 Sr ratios. Most probably the protolith of the granitic and granulitic rocks is of Palaeoproterozoic age in this part of the Madurai Block. The minimum age of granulite grade of metamorphism has been inferred at c. 850 Ma, indirectly on the basis of Rb-Sr ages of leptynites, which normally form during the evolution of granulite facies assemblages. Both granulite facies metamorphism and granitic magmatism probably took place during Neoproterozoic period correlatable to the early phase of Pan-African orogeny. Later decompression, causing mineral scale resetting of the Rb-Sr and Sm-Nd systematics, around 450-550 Ma, may correspond to the final exhumation, which brought the middle to lower crustal granulites to upper crustal levels, during the last phase of Pan-African activity. As per ages obtained on various lithounits in the present study the Metasedimentary Group of rocks (Mesoproterozoic) are younger than the Charnockite Group of rocks (Palaeoproterozoic) followed by the rocks belonging to the Migmatite Complex

  6. High frequency measurement of P- and S-wave velocities on crystalline rock massif surface - methodology of measurement

    Vilhelm, Jan; Slavík, Lubomír

    2014-05-01

    For the purpose of non-destructive monitoring of rock properties in the underground excavation it is possible to perform repeated high-accuracy P- and S-wave velocity measurements. This contribution deals with preliminary results gained during the preparation of micro-seismic long-term monitoring system. The field velocity measurements were made by pulse-transmission technique directly on the rock outcrop (granite) in Bedrichov gallery (northern Bohemia). The gallery at the experimental site was excavated using TBM (Tunnel Boring Machine) and it is used for drinking water supply, which is conveyed in a pipe. The stable measuring system and its automatic operation lead to the use of piezoceramic transducers both as a seismic source and as a receiver. The length of measuring base at gallery wall was from 0.5 to 3 meters. Different transducer coupling possibilities were tested namely with regard of repeatability of velocity determination. The arrangement of measuring system on the surface of the rock massif causes better sensitivity of S-transducers for P-wave measurement compared with the P-transducers. Similarly P-transducers were found more suitable for S-wave velocity determination then P-transducers. The frequency dependent attenuation of fresh rock massif results in limited frequency content of registered seismic signals. It was found that at the distance between the seismic source and receiver from 0.5 m the frequency components above 40 kHz are significantly attenuated. Therefore for the excitation of seismic wave 100 kHz transducers are most suitable. The limited frequency range should be also taken into account for the shape of electric impulse used for exciting of piezoceramic transducer. The spike pulse generates broad-band seismic signal, short in the time domain. However its energy after low-pass filtration in the rock is significantly lower than the energy of seismic signal generated by square wave pulse. Acknowledgments: This work was partially

  7. Annotated bibliography of selected reports relating to the isolation of nuclear waste in crystalline rock

    1988-06-01

    BMI/OCRD-29 is an annotated bibliography of published reports that have been produced for the US Department of Energy Crystalline Repository Project Office or the Swedish-American Cooperative Program on Radioactive Waste Storage in Mined Caverns. This document consists of a main report listing of citations and abstracts and a topical index

  8. Modeling of damage, permeability changes and pressure responses during excavation of the TSX tunnel in granitic rock at URL, Canada

    Rutqvist, Jonny; Börgesson, Lennart; Chijimatsu, Masakazu; Hernelind, Jan; Jing, Lanru; Kobayashi, Akira; Nguyen, Son

    2009-05-01

    This paper presents numerical modeling of excavation-induced damage, permeability changes, and fluid-pressure responses during excavation of a test tunnel associated with the tunnel sealing experiment (TSX) at the Underground Research Laboratory (URL) in Canada. Four different numerical models were applied using a wide range of approaches to model damage and permeability changes in the excavation disturbed zone (EDZ) around the tunnel. Using in situ calibration of model parameters, the modeling could reproduce observed spatial distribution of damage and permeability changes around the tunnel as a combination of disturbance induced by stress redistribution around the tunnel and by the drill-and-blast operation. The modeling showed that stress-induced permeability increase above the tunnel is a result of micro and macrofracturing under high deviatoric (shear) stress, whereas permeability increase alongside the tunnel is a result of opening of existing microfractures under decreased mean stress. The remaining observed fracturing and permeability changes around the periphery of the tunnel were attributed to damage from the drill-and-blast operation. Moreover, a reasonably good agreement was achieved between simulated and observed excavation-induced pressure responses around the TSX tunnel for 1 year following its excavation. The simulations showed that these pressure responses are caused by poroelastic effects as a result of increasing or decreasing mean stress, with corresponding contraction or expansion of the pore volume. The simulation results for pressure evolution were consistent with previous studies, indicating that the observed pressure responses could be captured in a Biot model using a relatively low Biot-Willis’ coefficient, α ≈ 0.2, a porosity of n ≈ 0.007, and a relatively low permeability of k ≈ 2 × 10-22 m2, which is consistent with the very tight, unfractured granite at the site.

  9. Stability and predictability in younger crystalline rock system: Japanese Islands case

    Yoshida, S.

    2009-01-01

    The Japanese Islands consist of igneous, sedimentary, and metamorphic rocks ranging in age from Paleozoic to Cenozoic. Among these, Carboniferous to Paleogene rocks occupy about 60% of the total area of the Japanese Islands. It should be noted that Quaternary volcanic rocks occupy only about 9% of the total area, although Quaternary volcanoes occur throughout the Japanese Islands. Long-term stability and predictability in the rock system are discussed in terms of volcanic activity, active faulting, and plate motion. Volcanic activity in the Japanese Islands is intimately related to subduction of the Pacific Plate and the Philippine Sea Plate. The volcanic front related to the Pacific and the Philippine Sea plates has been essentially fixed since about 6 Ma. The main active faults, which are distributed sporadically throughout the Japanese Islands, number about 150 and have been extensively investigated. The modes of the Pacific Plate and the Philippine Sea Plate have been essentially invariable since 10 Ma and 6 Ma, respectively. These lines of evidence imply that volcanism and tectonism in the Japanese Islands will scarcely change for hundreds of thousands of years into the future. It is clear that many places suitable for geological disposal will be present in this rock system. (author)

  10. Fracturing process and effect of fracturing degree on wave velocity of a crystalline rock

    Charalampos Saroglou

    2017-10-01

    Full Text Available The present paper investigates the effect of fracturing degree on P- and S-wave velocities in rock. The deformation of intact brittle rocks under loading conditions is characterized by a microcracking procedure, which occurs due to flaws in their microscopic structure and propagates through the intact rock, leading to shear fracture. This fracturing process is of fundamental significance as it affects the mechanical properties of the rock and hence the wave velocities. In order to determine the fracture mechanism and the effect of fracturing degree, samples were loaded at certain percentages of peak strength and ultrasonic wave velocity was recorded after every test. The fracturing degree was recorded on the outer surface of the sample and quantified by the use of the indices P10 (traces of joints/m, P20 (traces of joints/m2 and P21 (length of fractures/m2. It was concluded that the wave velocity decreases exponentially with increasing fracturing degree. Additionally, the fracturing degree is described adequately with the proposed indices. Finally, other parameters concerning the fracture characteristics, rock type and scale influence were found to contribute to the velocity decay and need to be investigated further.

  11. Petrochemistry and zircon U-Pb geochronology of granitic rocks in the Wang Nam Khiao area, Nakhon Ratchasima, Thailand: Implications for petrogenesis and tectonic setting

    Fanka, Alongkot; Tsunogae, Toshiaki; Daorerk, Veerote; Tsutsumi, Yukiyasu; Takamura, Yusuke; Sutthirat, Chakkaphan

    2018-05-01

    Carboniferous biotite granite, Late Permian hornblende granite, and Triassic biotite-hornblende granite, all of which belong to the Eastern Granite Belt, expose in the Wang Nam Khiao area, Nakhon Ratchasima, northeastern Thailand. The Carboniferous biotite granite is dominated by quartz, K-feldspar, plagioclase, and biotite. The Late Permian hornblende granite contains dominant assemblages of plagioclase, quartz, K-feldspar, hornblende, and minor amount of biotite, while the Triassic biotite-hornblende granite consists of quartz, plagioclase, K-feldspar with small amounts of biotite, and hornblende. The REE patterns with steep decrease from light to heavy REE together with the LILE (e.g. K, Sr) enrichment and depletion of some particular HFSE (e.g. Nb, Ti) indicate low degree of partial melting. Mineral chemistry of biotite and hornblende in the granites reflects crystallization from hydrous calc-alkaline arc-derived magmas possibly formed by subduction. Amphibole-plagioclase thermometry and Al-in-hornblende barometry indicate that the Late Permian hornblende granite and the Triassic biotite-hornblende granite may have equilibrated at 3.0-5.8 kbar/700-820 °C and 2.0-3.2 kbar/600-750 °C, respectively, in the middle-upper crust (about 10-15 km depth). Zircon U-Pb geochronology of the Carboniferous biotite granite, Late Permian hornblende granite and Triassic biotite-hornblende granite yielded intrusion ages of 314.6-284.9 Ma, 253.4 Ma, and 237.8 Ma, respectively, which implies multiple episodes of arc-magmatism formed by Palaeo-Tethys subduction beneath Indochina Terrane during Late Carboniferous/Early Permian, Late Permian and Middle Triassic.

  12. Hydro-mechanical modelling of a shaft seal in crystalline and sedimentary host rock media using COMSOL

    Priyanto, D.G. [Atomic Energy of Canada Limited, Pinawa, MB (Canada)

    2011-07-01

    Shaft seals are components of the engineered barriers system considered for closure of a Deep Geological Repository (DGR). These seals would be installed in strategic locations of the shafts, where significant fracture zones (FZ) are located and would serve to limit upward flow of groundwater from the repository level towards the surface. This paper presents the results of hydro-mechanical (HM) numerical modelling exercises to evaluate the performance of a shaft seal using a finite element computer code, COMSOL. This study considered a variety of host geological media as part of generic assessments of system evolution in a variety of environments including five hypothetical sedimentary and crystalline host rock conditions. Four simulations of a shaft seal in different sedimentary rocks were completed, including: shale with isotropic permeability; shale with anisotropic permeability; limestone with isotropic permeability; and limestone with anisotropic permeability. The other simulation was a shaft seal in crystalline rock with isotropic permeability. Two different stages were considered in these HM simulations. Stages 1 and 2 simulated the groundwater flow into an open shaft and after installation of shaft sealing components, respectively. As expected, the models were able to simulate that installation of the shaft seal limits groundwater flow through the shaft. Based on the conditions and assumptions defined for the host media and fracture features examined in this study, the following conclusions can be drawn from the results of the numerical modelling exercises. A shaft that remained open for a longer time was beneficial with respect to delaying of seal saturation because it could reduce the groundwater flow rate around the fracture zone. Delaying saturation time indicates slower movement of the groundwater or other substances that may be transported with the groundwater. The core of the shaft seal (i.e., the bentonite-sand mixture (BSM)) became fully saturated

  13. In Situ Experiment and Numerical Model Validation of a Borehole Heat Exchanger in Shallow Hard Crystalline Rock

    Mateusz Janiszewski

    2018-04-01

    Full Text Available Accurate and fast numerical modelling of the borehole heat exchanger (BHE is required for simulation of long-term thermal energy storage in rocks using boreholes. The goal of this study was to conduct an in situ experiment to validate the proposed numerical modelling approach. In the experiment, hot water was circulated for 21 days through a single U-tube BHE installed in an underground research tunnel located at a shallow depth in crystalline rock. The results of the simulations using the proposed model were validated against the measurements. The numerical model simulated the BHE’s behaviour accurately and compared well with two other modelling approaches from the literature. The model is capable of replicating the complex geometrical arrangement of the BHE and is considered to be more appropriate for simulations of BHE systems with complex geometries. The results of the sensitivity analysis of the proposed model have shown that low thermal conductivity, high density, and high heat capacity of rock are essential for maximising the storage efficiency of a borehole thermal energy storage system. Other characteristics of BHEs, such as a high thermal conductivity of the grout, a large radius of the pipe, and a large distance between the pipes, are also preferred for maximising efficiency.

  14. Near-field thermal transient and thermomechanical stress analysis of a disposal vault in crystalline hard rock

    Tsui, K.K.; Tsai, A.; Lee, C.F.

    1981-01-01

    The Canadian Nuclear Fuel Waste Management Program currently focuses on the development of a disposal vault in crystalline hard rock at a reference depth of 1 km below the surface in a suitable pluton in the Canadian Shield. As part of Ontario Hydro's technical assistance to the Atomic Energy of Canada Limited in this program, studies are being carried out to determine the effects of radiogenic heat on the near-field behaviour of a disposal vault. This paper presents the study results obtained to date. Temperature and stress fields were computed and cross-checked by several finite element codes. A comparison between vertical and horizontal borehole emplacement concepts is made. The effects of material non-linearity (temperature dependence) and three-dimensionality on the thermomechanical response are evaluated. Case histories of thermal spalling or fracturing in rock were summarized and discussed to illustrate the possible mechanisms and processes involved in thermal fracturing. An assessment of the thermomechanical stability of the rock mass around a disposal vault under a state of high horizontal in-situ stress is also presented

  15. Studies on groundwater transport in fractured crystalline rock under controlled conditions using nonradioactive tracers

    Gustafsson, E.; Klockars, C.-E.

    1981-04-01

    The purpose of the investigation has been study the following parameters along existing fractures between two boreholes: hydraulic properties of rock mass and fractures; adsorptive properties of some selected tracers during transport along fractures; dispersivity and dilution of tracers during transport in fractures; kinematic porosity of fractured bedrock. The procedure has been to determine the hydraulic properties of a rock mass by means of conventional hydraulic testing methods in 100 m deep boreholes, and to study transport mechanisms and properties of selected tracers in a selected fracture zone between two boreholes. (Auth.)

  16. Investigations of possibilities to dispose of spent nuclear fuel in Lithuania: a model case. Volume 2, Concept of Repository in Crystalline Rocks

    Motiejunas, S.; Poskas, P.

    2005-01-01

    The aim is to present the generic repository concept in crystalline rocks in Lithuania and cost assessment of the disposal of spent nuclear fuel and long-lived intermediate level waste in this repository. Due to limited budget of this project the repository concept development for Lithuania was based mostly on the experience of foreign countries. In this Volume a review of the existing information on disposal concept in crystalline rocks from various countries is presented. Described repository concept for crystalline rocks in Lithuania covers repository layout, backfill, canister, construction materials and auxiliary buildings. Costs calculations for disposal of spent nuclear fuel and long-lived intermediate-level wastes from Ignalina NPP are presented too. Thermal, criticality and other important disposal evaluations for RBMK-1500 spent nuclear fuel emplaced in copper canister were performed and described

  17. Application of streaming potential method for detection of fractures in granitic rock; Kamaishi kozan ni okeru ryutai ryudo den`iho tekiyo shiken

    Negi, T; Yokoi, K; Yoneda, Y [Nittetsu Mining Co. Ltd., Tokyo (Japan); Senba, T [Power Reactor and Nuclear fuel Development Corporation, Tokyo (Japan)

    1996-05-01

    Measurements were made using the streaming potential method for the purpose of investigating the expansion of hydration cracks, direction of their propagation, and the chaining of cracked surfaces, in the granitic rock. Tests were conducted by use of a bore hole in the gallery wall. The bore hole yielded approximately 400 liters of water per minute, the bore hole was closed and then opened, and the change with the passage of time in the spontaneous potential (SP) on the gallery wall was measured. At a spot 31.2m from the mine entrance, the SP dropped by 15mV simultaneously with the opening of the bore hole, and rose by 14mV simultaneously with the closure of the same. The phenomenon was true for other locations, that is, for the section from the mine entrance to a spot 9.0m therefrom, and for a section beginning at 15.0m and ending at 19.2m therefrom. No change in the SP was observed in a group of cracks with water springing out of the gallery roof, beginning at a point 40m and ending at a point 54m from the mine entrance. The result suggests the possible application of the streaming potential method to the investigation of cracks. 1 ref., 10 figs.

  18. Deep ground water microbiology in Swedish granite rock and it's relevance for radio-nuclide migration from a Swedish high level nuclear waste repository

    Pedersen, Karsten

    1989-03-01

    Data on numbers, species and activity of deep ground water microbial populations in Swedish granite rock have been collected. Specific studies are performed on radio-nuclid uptake on bacteria judge to be probable inhabitants in Swedish nuclear waste repositories. An integrated mobile field laboratory was used for water sampling and for the immediate counting and inoculation of the samples from boreholes at levels between 129 and 860 m. A sampler adapted for the collection of undisturbed samples for gas analysis was used to collect samples for bacterial enumerations and enrichments. The sampler can be opened and closed from the surface at the actual sampling depth. The samples can subsequently be brought to the surface without contact with air and with the pressure at the actual sampling depth. The number of bacteria were determined in samples from the gas sampler when this was possible. Else numbers are determined in the water that is pumped up to the field lab. The average total number of bacteria is 3 x 10 5 bacterial ml -1 . The number of bacteria possible to recover with plate count arrays from 0.10 to 21.9%. (author)

  19. Present status of the interlaboratorial co-operative study for standards rocks of granite (GB-1) and basalt (BB-1) from the Geochemistry Department of I.G.U.F. Ba./Brazil

    Linhares, P.S.

    1987-01-01

    Results for major, minor and trace elements obtained by twelve laboratories for the standards rocks, Granite (GB-1) and Basalte (BB-1), of the Geochemistry Department of Geociences Institute-U-F.Ba are presented. At present status of the study it is possible to approach the most probably correct value (usable value) for the concentration of each of the major and minor elements. (author) [pt

  20. Advances in Geologic Disposal System Modeling and Application to Crystalline Rock

    Mariner, Paul E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stein, Emily R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Frederick, Jennifer M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sevougian, S. David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hammond, Glenn Edward [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fascitelli, D. G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-09-22

    The Used Fuel Disposition Campaign (UFDC) of the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE), Office of Fuel Cycle Technology (OFCT) is conducting research and development (R&D) on geologic disposal of used nuclear fuel (UNF) and high-level nuclear waste (HLW). Two of the high priorities for UFDC disposal R&D are design concept development and disposal system modeling (DOE 2011). These priorities are directly addressed in the UFDC Generic Disposal Systems Analysis (GDSA) work package, which is charged with developing a disposal system modeling and analysis capability for evaluating disposal system performance for nuclear waste in geologic media (e.g., salt, granite, clay, and deep borehole disposal). This report describes specific GDSA activities in fiscal year 2016 (FY 2016) toward the development of the enhanced disposal system modeling and analysis capability for geologic disposal of nuclear waste. The GDSA framework employs the PFLOTRAN thermal-hydrologic-chemical multi-physics code and the Dakota uncertainty sampling and propagation code. Each code is designed for massively-parallel processing in a high-performance computing (HPC) environment. Multi-physics representations in PFLOTRAN are used to simulate various coupled processes including heat flow, fluid flow, waste dissolution, radionuclide release, radionuclide decay and ingrowth, precipitation and dissolution of secondary phases, and radionuclide transport through engineered barriers and natural geologic barriers to the biosphere. Dakota is used to generate sets of representative realizations and to analyze parameter sensitivity.

  1. Structure of aluminosilicate melts produced from granite rocks for the manufacturing of petrurgical glass-ceramics construction materials

    Simakin, A. G.

    2001-12-01

    Full Text Available The aluminosilicate melt is a partly ordered phase and is the origin of glass for producing glassceramics and petrurgical materials. They are well extended used as construction materials for pavings and coatings. Its structure can be described in the terms of the aluminosilica tetrahedras coordination so-called Q speciation. The proportions of tetrahedra with different degree of connectivity with others (from totally connected to free has been studied by NMR and IR methods for sodium-silicate melts. Medium range structure can be characterized by the sizes of irreducible rings composed of the aluminosilica tetrahedra. Systematic increase of the four member rings proportion in the sequence of the Ab-An glasses were observed. The water dissolution in sodium-silicate glass affects the Q speciation. Cations network-modifiers positions in the melt structure are important to know since these cations stabilize particular structure configurations. Modification of the distribution of Na coordination in the sodium-silicate glass at water dissolution was determined by NMR spectroscopy. The observed modification of the hydrous aluminosilicate melt structure resulted in the shift of the eutectic composition in the granite system with decreasing of the crystallization field of feldspars. The feldspar growth rates show practically no dependence on the water content in the concentration range 2-4 wt.%. Likewise, the solved water has a little influence on the crystal growth rate of the lithium silicate phase in lithium containing glasses in accordance with estimated enhancing of the diffusion transport.

    Los fundidos de alumino-silicato son una fase parcialmente ordenada. Su estructura puede ser descrita en términos de la coordinación de tetraedros de alúmina-sílice también denominados especies Q. La proporción de tetraedros con diferente grado de conectividad entre si se ha investigado por espectroscopias de RMN e IR en fundidos de silicatos

  2. Time dependent fracture growth in intact crystalline rock: new laboratory procedures

    Backers, T.; Stephansson, O.

    2008-01-01

    Short term laboratory tests to determine the strength of rock material are commonly used to assess stability of rock excavations. However, loading the rock below its short term strength may lead to delayed failure due to slow stable fracture growth. This time-dependent phenomenon is called subcritical fracture growth. A fracture mechanics based approach is applied in this study to determine the parameters describing subcritical fracture growth under Mode Ⅰ (tensile) and Mode Ⅱ (in-plane shear) loading in terms of the stress intensity factors of saturated granodiorite from the) Aespoe HRL. A statistical method is applied to data from three-point bending (tension) and Punch-Through Shear with Confining Pressure, PTS/CP, (shear) experiments. One population of each set-up was subjected to rapid loading tests yielding a strength probability distribution. A second population was loaded up to a certain fraction of the statistical percentage for failure and the time-to-failure was determined. From these two populations the subcritical fracture growth parameters were determined successfully. Earlier studies demonstrated subcritical fracture growth under Mode I loading conditions, but this study shows that under a Mode Ⅱ load time-dependent fracture growth exists as well. (authors)

  3. A tale of 10 plutons - Revisited: Age of granitic rocks in the White Mountains, California and Nevada

    McKee, E.H.; Conrad, J.E.

    1996-01-01

    40Ar/39Ar incremental heating analysis and conventional K-Ar age determinations on plutonic rocks of the White Mountains define two stages of magmatic emplacement: Late Cretaceous, between ca. 90 Ma and 75 Ma, and Middle-Late Jurassic, between ca. 180 and 140 Ma. The Jurassic stage can be divided into two substages, 180-165 Ma and 150-140 Ma. Thermal effects of the younger plutons on the older granitoids partially to completely reset ages, making it difficult to determine the age of emplacement and cooling of several of the plutons even by 40Ar/39Ar incremental heating analyses. New data together with published ages and regional geochronological synthesis of the Sierra Nevada batholith indicate that regions within the batholith have coherent periods or episodes of magmatic activity. In the White Mountains and Sierra Nevada directly to the west there was little or no activity in Early Jurassic and Early Cretaceous time; magmatism took place during relatively short intervals of 15 m.y. or less in the Middle and Late Jurassic and Late Cretaceous periods. The new K-Ar and 40Ar/39Ar analyses of granitoids from the White Mountains help, but do not completely clarify the complex history of emplacement, cooling, and reheating of the batholith.

  4. Contribution to uranium geochemistry in intrusive granites

    Coulomb, R.

    1959-01-01

    This work aims to define the position of a certain number of French granitic deposits within the field of the geochemistry of granites in general, and of the geochemistry of uranium in particular. The regions concerned are: - 3 French Hercynian ranges, in the Vendee, in Brittany and in the Morvan, - 1 African range, probably precambrian, of the Hoggar. For each range, the petrochemical framework is first of all determined and then the degree of chemical homogeneity of the rocks is evaluated. In the petrochemical groups thus obtained the geochemical behaviour of the uranium is studied. From a point of view of the geochemistry of the granites under investigation, a comparison of the laws of distribution of the major elements in the 4 ranges shows up a convergence of average composition which was not anticipated by geological and petrographic considerations alone. The statistical and geochemical distribution laws of the total uranium as a function of the petrochemical variations are established. A study of the chemical forms of uranium in the rocks has drawn an attention to the qualitative and quantitative importance of the fraction of this uranium soluble in dilute acids. We have therefore reconsidered on the one hand, the laws of distribution of the insoluble uranium, which represents essentially the uranium fixed in crystalline structures (zircon, allanite...), and we have justified on the other hand the interest presented by the soluble uranium: this, although more complex in character, presents a geochemical unity in post magmatic phenomena which makes possible to find a genetic connection between the uraniferous deposits and the intrusive massifs. Finally we have given a plan of the geochemical cycle of uranium, in which we hope to have provided some more accurate data on the igneous phase. (author) [fr

  5. Distribution coefficient of radionuclides on rocks for performance assessment of high-level radioactive waste repository

    Shibutani, Tomoki; Shibata, Masahiro; Suyama, Tadahiro

    1999-11-01

    Distribution coefficients of radionuclides on rocks are selected for safety assessment in the 'Second Progress Report on Research and Development for the geological disposal of HLW in Japan (H12 Report)'. The categorized types of rock are granitic rocks (crystalline and acidic rocks), basaltic rocks (crystalline and basic rocks), psammitic rocks (neogene sedimentary (soft)), and tuffaceous-pelitic rocks (pre-neogene sedimentary rocks (hard)). The types of groundwater are FRHP (fresh reducing high-pH), FRLP (fresh reducing low-pH), SRHP (saline reducing high-pH), SRLP (saline reducing low-pH), MRNP (mixing reducing neutral-pH) and FOHP (fresh oxidizing high-pH) groundwater. The elements to be surveyed are Ni, Se, Zr, Nb, Tc, Pd, Sn, Cs, Sm, Pb, Ra, Ac, Th, Pa, U, Np, Pu, Am and Cm. Distribution coefficients are collected from literatures describing batch sorption experimental results, and are selected under consideration of conservativity. (author)

  6. Methodology for deriving hydrogeological input parameters for safety-analysis models - application to fractured crystalline rocks of Northern Switzerland

    Vomvoris, S.; Andrews, R.W.; Lanyon, G.W.; Voborny, O.; Wilson, W.

    1996-04-01

    Switzerland is one of many nations with nuclear power that is seeking to identify rock types and locations that would be suitable for the underground disposal of nuclear waste. A common challenge among these programs is to provide engineering designers and safety analysts with a reasonably representative hydrogeological input dataset that synthesizes the relevant information from direct field observations as well as inferences and model results derived from those observations. Needed are estimates of the volumetric flux through a volume of rock and the distribution of that flux into discrete pathways between the repository zones and the biosphere. These fluxes are not directly measurable but must be derived based on understandings of the range of plausible hydrogeologic conditions expected at the location investigated. The methodology described in this report utilizes conceptual and numerical models at various scales to derive the input dataset. The methodology incorporates an innovative approach, called the geometric approach, in which field observations and their associated uncertainty, together with a conceptual representation of those features that most significantly affect the groundwater flow regime, were rigorously applied to generate alternative possible realizations of hydrogeologic features in the geosphere. In this approach, the ranges in the output values directly reflect uncertainties in the input values. As a demonstration, the methodology is applied to the derivation of the hydrogeological dataset for the crystalline basement of Northern Switzerland. (author) figs., tabs., refs

  7. Immobilization of uranium in biofilm microorganisms exposed to groundwater seeps over granitic rock tunnel walls in Olkiluoto, Finland

    Krawczyk-Bärsch, Evelyn; Lünsdorf, Heinrich; Pedersen, Karsten; Arnold, Thuro; Bok, Frank; Steudtner, Robin; Lehtinen, Anne; Brendler, Vinzenz

    2012-11-01

    In an underground rock characterization facility, the ONKALO tunnel in Finland, massive 5-10-mm thick biofilms were observed attached to tunnel walls where groundwater was seeping from bedrock fractures at a depth of 70 m. In laboratory experiments performed in a flow cell with detached biofilms to study the effect of uranium on the biofilm, uranium was added to the circulating groundwater (CGW) obtained from the fracture feeding the biofilm. The final uranium concentration in the CGW was adjusted to 4.25 × 10-5 M, in the range expected from a leaking spent nuclear fuel (SNF) canister in a future underground repository. The effects were investigated using microelectrodes to measure pH and Eh, time-resolved laser fluorescence spectroscopy (TRLFS), energy-filtered transmission electron microscopy (EF-TEM), and electron energy-loss spectroscopy (EELS) studies and thermodynamic calculations were utilized as well. The results indicated that the studied biofilms constituted their own microenvironments, which differed significantly from that of the CGW. A pH of 5.37 was recorded inside the biofilm, approximately 3.5 units lower than the pH observed in the CGW, due to sulfide oxidation to sulfuric acid in the biofilm. Similarly, the Eh of +73 mV inside the biofilm was approximately 420 mV lower than the Eh measured in the CGW. Adding uranium increased the pH in the biofilm to 7.27 and reduced the Eh to -164 mV. The changes of Eh and pH influenced the bioavailability of uranium, since microbial metabolic processes are sensitive to metals and their speciation. EF-TEM investigations indicated that uranium in the biofilm was immobilized intracellularly in microorganisms by the formation of metabolically mediated uranyl phosphate, similar to needle-shaped autunite (Ca[UO2]2[PO4]2·2-6H2O) or meta-autunite (Ca[UO2]2[PO4]2·10-12H2O). In contrast, TRLFS studies of the contaminated CGW identified aqueous uranium carbonate species, likely (Ca2UO2[CO3]3), formed due to the high

  8. Rock glaciers in crystalline catchments: Hidden permafrost-related threats to alpine headwater lakes.

    Ilyashuk, Boris P; Ilyashuk, Elena A; Psenner, Roland; Tessadri, Richard; Koinig, Karin A

    2018-04-01

    A global warming-induced transition from glacial to periglacial processes has been identified in mountainous regions around the world. Degrading permafrost in pristine periglacial environments can produce acid rock drainage (ARD) and cause severe ecological damage in areas underlain by sulfide-bearing bedrock. Limnological and paleolimnological approaches were used to assess and compare ARDs generated by rock glaciers, a typical landform of the mountain permafrost domain, and their effects on alpine headwater lakes with similar morphometric features and underlying bedrock geology, but characterized by different intensities of frost action in their catchments during the year. We argue that ARD and its effects on lakes are more severe in the alpine periglacial belt with mean annual air temperatures (MAAT) between -2°C and +3°C, where groundwater persists in the liquid phase for most of the year, in contrast to ARD in the periglacial belt where frost action dominates (MAAT cycle of aquatic organisms should be considered when reconstructing long-term trends in the ecotoxicological state of lakes. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

  9. On the possibility of determining rates of removal of uranium from crystalline igneous rocks using U - series disequilibria - 1: a U-leach model, and its applicability to whole-rock data

    Latham, A.G.; Schwarcz, H.P.

    1987-01-01

    The removal of U from granitic rocks is characterised by 234 U/ 238 U 230 Th/ 234 U > 1. It is notable, from weathered Eye-Dashwa lakes (Canada) granite samples and from the published data, that 230 Th/ 234 U ratios seldom exceed a limiting value of about 2. A U-leach model is discussed in detail which may account for these observations. The model assumes that 230 Th is practically immobile and that the removal of U can then be measured against the decay rate of the unsupported 230 Th. A property of the model is that the isotope ratios reach constant values reflecting a kind of ''secular equilibrium'', and this implies that U is seldom removed faster than the decay of 230 Th. If the limited 230 Th/ 234 U ratios from the data correspond to ''secular equilibrium'' ratios then this allows simple calculation of U-leach rates from any given subsurface sample. (author)

  10. Scoping study of salt domes, basalts and crystalline rock as related to long term risk modeling for deep geologic disposal of nuclear waste

    1978-11-01

    Purpose is to provide a preliminary geotechnical data base sufficient to initiate the development of Long-Term Risk Models for salt domes, basalt, and crystalline rock. Geology, hydrology, specific sites, and potential release pathways are considered for each type. A summary table of site suitability characteristics is presented

  11. Natural radionuclide distribution in Brazilian commercial granites

    Anjos, R.M.; Veiga, R.; Soares, T.; Santos, A.M.A.; Aguiar, J.G.; Frasca, M.H.B.O.; Brage, J.A.P.; Uzeda, D.; Mangia, L.; Facure, A.; Mosquera, B.; Carvalho, C.; Gomes, P.R.S.

    2005-01-01

    The dimension stones sector in Brazil produces several varieties of granites, marbles, slates and basalts. More than half of this production corresponds to around 200 different commercial types of granites with specific names, geographical and geological origins and mineral compositions. The well-known natural radioactivity present in rocks, where high radiation levels are associated with igneous rocks such as granite, can be used to determine their general petrologic features. This subject is important in environmental radiological protection, since granites are widely used as building and ornamental stones. In this paper, it is applied to correlate the petrographic characteristics of commercial granites with their corresponding dose rates for natural radioactivity. Amounts of thorium, uranium and potassium concentrations have been reported in several Brazilian commercial granite samples

  12. Status of LLNL granite projects

    Ramspott, L.D.

    1980-01-01

    The status of LLNL Projects dealing with nuclear waste disposal in granitic rocks is reviewed. This review covers work done subsequent to the June 1979 Workshop on Thermomechanical Modeling for a Hardrock Waste Repository and is prepared for the July 1980 Workshop on Thermomechanical-Hydrochemical Modeling for a Hardrock Waste Repository. Topics reviewed include laboratory determination of thermal, mechanical, and transport properties of rocks at conditions simulating a deep geologic repository, and field testing at the Climax granitic stock at the USDOE Nevada Test Site

  13. Hydrological characteristics of Japanese rock

    Ijiri, Yuji; Sawada, Atsushi; Akahori, Kuniaki

    1999-11-01

    It is crucial to evaluate the hydrogeological characteristics of rock in Japan in order to assess the performance of geosphere. This report summarizes the hydrogeological characteristics of various rock types obtained from broad literature surveys and the fields experiments at the Kamaishi mine in northern Japan and at the Tono mine in central Japan. It is found that the hydraulic conductivity of rock mass ranges from 10 -9 m/s to 10 -8 m/s, whereas the hydraulic conductivity of fault zone ranges from 10 -9 m/s to 10 -3 m/s. It is also found that the hydraulic conductivity tends to decrease with depth. Therefore, the hydraulic conductivity of rock mass at the depth of a repository will be smaller than above values. From the investigations at outcrops and galleries throughout the country, fractures are observed as potential pathways in all rock types. All kinds of crystalline rocks and pre-Neogene sedimentary rocks are classified as fractured media where fracture flow is dominant. Among these rocks, granitic rock is considered the archetype fractured media. On the other hand, andesite, tuff and Neogene sedimentary rocks are considered as intermediate between fractured media and porous media where flow in fractures as well as in rock matrix are significant. (author)

  14. Petrography, mineral chemistry and lithochemistry of the albitite and granite-gneissics rocks of anomaly 35 from Lagoa Real uranium province; Petrografia, quimica mineral e litoquimica do albitito e das rochas granito-gnaissicas da anomalia 35, provincia uranifera de Lagoa Real

    Santos, Camila Marques dos

    2016-07-01

    In the northwestern portion of the Lagoa Real Uranium Province (LRUP), located in south-central Bahia, it is located one of the most promising uranium anomalies Brazil (an35, Gameleira I deposit), the reserves and proximity to the Cachoeira mine. Other anomalies of this sector (eg. 31 AN and AN34), are also considered strategic for the content of radioactive minerals and REE. The objective was to develop a study of a representative drill core of an35, where the main rocks PULR are present. The research focused on the mineralogical and chemical changes observed in the passages of a lithology to another, from the rock to the meta granitic albitites, through gneiss and transitional rocks, and making comparisons with similar lithologies sampled on testimonies of AN31 and 34. The granites are classified as hypersolvus coarse alkali-feldspar granite and are variably deformed. The main mineral assemblage in granites are perthitic orthoclase+hedenbergite+ quartz +hastingsite + biotite, and zircon, apatite, ilmenite and titanite are accessories. The reddening of these rocks are characterized by feldspars sericitization and hematitization and the presence of 'vazios'. The gneisses are mainly gray and reach milonitic to protomilonitics terms. These rocks have characteristics of subsolidus changes as swapped rims and metasomatic perthites. The tardi-magmatic association (amphibole+biotite) indicates final crystallization or late influx by superficial fluids resulting in an increase in water and volatiles, such as F and Cl in the system, which must also have carried rare-earth elementsGranites have geochemical affinity with A-type ferroan granite, A2, reduced and are post-collisional. Their patterns of incompatible elements and rare earths are comparable to Sao Timoteo Granite, but their petrographic features indicate that it is a less common granite facies. Albitites were classified as garnet albitites, magnetite albitites and biotite albitites. Contacts between

  15. A conceptual hydrodynamic model of a geological discontinuity in hard rock aquifers: Example of a quartz reef in granitic terrain in South India

    Dewandel, Benoît; Lachassagne, Patrick; Zaidi, Faisal K.; Chandra, Subash

    2011-08-01

    SummaryThe structure and hydrodynamic properties of geological discontinuities and of a deeply weathered granite aquifer near these structures are described on the basis of geological, geophysical and hydrodynamic investigations in two sites of South India located along a 20-40-m-wide quartz reef intruding a weathered Archean biotite granite. One of the two sites also comprises a metre-wide dolerite dyke. Weathering processes appear to be at the origin of fissures development and of a related enhanced local hydraulic conductivity, both in the quartz reef and in the surrounding granite. The weathering profile in the granite (saprolite and fissured layer) is characterized by an abrupt deepening of the weathered layers in the granite near the contact and in the quartz reef itself. Therefore, the weathering profile shows a 'U'-shape geometry with, among others, the verticalization of the granite's fissured layer. The hydraulic conductivity of this verticalized layer is on average 5 × 10 -6 m/s and storativity about 10 -3 (-). The hydraulic conductivity of the fissured quartz is 4-6 × 10 -6 m/s and its storativity about 3-5 × 10 -4 (-). Both media are also characterized by a matrix hydraulic conductivity (10 -7-10 -9 m/s) and by a significant heterogeneity in hydrodynamic properties that generates preferential flow paths along the sub-vertical fissures parallel to the reef axis. A special attention has been paid for characterizing this heterogeneity. The weathering of the dolerite dyke, however, results in a local low hydraulic conductivity, which consequently does not enhance either the thickness of weathered granite layers or its hydraulic conductivity. The obtained results complete the conceptual hydrogeological model developed for weathered granite aquifers in characterizing the relationships between weathering processes and hydrodynamic properties near geological discontinuities.

  16. Predictability of the evolution of hydrogeological and hydrogeochemical systems; geological disposal of nuclear waste in crystalline rocks

    Murphy, W.M.; Diodato, D.M.

    2009-01-01

    Confidence in long-term geologic isolation of high-level nuclear waste and spent nuclear fuel requires confidence in predictions of the evolution of hydrogeological and hydrogeochemical systems. Prediction of the evolution of hydrogeological and hydrogeochemical systems is based on scientific understanding of those systems in the present - an understanding that can be tested with data from the past. Crystalline rock settings that have been geologically stable for millions of years and longer offer the potential of predictable, long-term waste isolation. Confidence in predictions of geologic isolation of radioactive waste can measured by evaluating the extent to which those predictions and their underlying analyses are consistent with multiple independent lines of evidence identified in the geologic system being analysed, as well as with evidence identified in analogs to that geologic system. The proposed nuclear waste repository at Yucca Mountain, Nevada, United States, differs in significant ways from potential repository sites being considered by other nations. Nonetheless, observations of hydrogeological and hydrogeochemical systems of Yucca Mountain and Yucca Mountain analogs present multiple independent lines of evidence that can be used in evaluating long-term predictions of the evolution of hydrogeological and hydrogeochemical systems at Yucca Mountain. (authors)

  17. A review and synthesis of international proposals for the disposal of high-level radioactive wastes into crystalline rock formations

    1981-05-01

    Examination of the broad range of international concepts for the disposal of high-level radioactive wastes into crystalline rock formations has indicated that systems based upon solid waste units provide the greatest degree of engineering control and security. Three particular disposal concepts are considered worthy of detailed evaluation. In order of priority these are:-tunnel networks with 'in-floor' waste emplacement; matrix of vertical emplacement holes drilled from the surface; tunnel networks with 'in-room' waste emplacement. A review of the international literature has shown that at least ten countries have embarked upon study programmes, but only five have developed detailed conceptual design proposals. These are:- Canada, France, Sweden, the United Kingdom, and the United States. Differing economic, environmental, historical and political circumstances have influenced the pattern of international studies and, to the uninitiated, these factors may obscure some of the relevant technical considerations. Nevertheless, a broad technical concensus is apparent in that all countries currently favour tunnel networks with 'in-floor' waste emplacement. The subject is discussed in detail. (author)

  18. Survey of in situ testing at underground laboratories with application to geologic disposal of spent fuel waste in crystalline rock

    Hardin, E.

    1992-04-01

    This report is intended for use in designing testing programs, or as backup material for the review of 'R and D 92' which will be the next three-year plan for spent fuel repository siting and characterization activities in Sweden. There are eight major topics, each of which is addressed in a chapter of around 2000 to 10000 words. The major topics are defined to capture the reasons for testing, in a way that limits overlap between chapters. Other goals of this report are to provide current information on recent or ongoing tests in crystalline rock, and to describe insights which are important but not obvious from the literature. No data are presented, but the conclusions of testing programs are summarized. The principal sources were reports (in English) produced by the laboratory projects particularly the Stripa Project (SKB), the Underground Research Laboratory in Canada (AECL), and the Grimsel Test Site in Switzerland (Nagra). Articles from refereed journals have been used in lieu of project literature where possible and appropriate. (au)

  19. Using Landsat 5 imagery in the assessment of groundwater resources in the crystalline rocks around Dutsin-Ma, northwestern Nigeria

    Bala, A. E.; Batelaan, O.; De Smedt, F.

    2000-01-01

    Landsat's TM imagery of January 1986 covering Dustin - Ma and the surrounding areas in northwestern Nigeria was used for the assessment of groundwater resources in the crystalline rocks (Basement Complex) terrain. Employing ER Mapper (5.2), surface indicator for the occurrence of groundwater such as thriving vegetation in non - irrigated lands, and fracture were identified. These were interpreted vis - a - vis the tectonic development of the are. Lineaments interpreted as fractures show two prominent strike maxima that lie between 0000 and 0300, with the more common lying between 0000 and 0100. These strike maxima correspond to the stress axis of the Pan African orogeny. The lushness of vegetation along these strikes is higher than in the neighbouring areas and indicate the presence of groundwater. On the basis of lineament density and relative lushness of the vegetal cover, the area was divided into three main hydrogeological zones namely, the zones with the highest, intermediate, and least groundwater potential, for which ground truthing is recommended for their confirmation. Geophysical surveys for the siting of boreholes are also recommended parallel to strikes between 270 o and 300 o . It is judged that the groundwater resource for this area is low because of the general lack of moist or seepage areas, the low threshold value. (0.12) of Normalized Difference Vegetation Index (NDVI), and the generally dispersed nature of the vegetation

  20. Chemical Th-U-total Pb isochron ages of zircon and monazite from granitic rocks of the Negele area, southern Ethiopia

    Yihunie, Tadesse

    2003-01-01

    CHIME (Chemical Th-U-total Pb Isochron Method) age determinations were made on zircon and monazite grains from granitoid samples in the Negele area of southern Ethiopia. A 611±32 Ma zircon age was obtained from a syn-tectonic hornblende-biotite granite of the Alghe domain. A 453±29 Ma zircon age and a 459±16 Ma monazite age were also obtained from post-tectonic two-mica granites of the Alghe domain and the Kenticha domain, respectively. Since these ca. 450 Ma zircon and monazite ages coincide well, as significant post-tectonic granitic magmatism appears to have occurred in southern Ethiopia in early Paleozoid time. The new CHIME age results indicate at least two episodes of granitic magmatism in southern Ethiopia in the late Proterozoic to early Paleozoic, with a ca. 150 Ma interval between syn- and post-tectonic granitic emplacements, and have a important geochronological constraint on the evolution of the East African Orogen. (author)

  1. Basic investigation and analysis for preferred host rocks and natural analogue study area with reference to high level radioactive waste disposal

    Seo, Jeong Ryul; Park, J. K.; Hwang, D. H.; Lee, J. H.; Yun, H. S.; Kim, D. Y.; Park, H. S.; Koo, S. B.; Cho, J. D.; Kim, K. E. [Korea Inst. of Geology, Mining and Materials, Taejon (Korea, Republic of)

    1997-12-01

    The purpose of this study is basic investigation and analysis for preferred host rocks and natural analogue study area to develope underground disposal technique of high level radioactive waste in future. The study has been done for the crystalline rocks(especially granitic rocks) with emphasis of abandoned metallic mines and uranium ore deposits, and for the geological structure study by using gravity and aeromagnetic data. 138 refs., 54 tabs., 130 figs. (author)

  2. Development and testing of radionuclide transport models for fractured crystalline rock. An overview of the Nagra/JNC radionuclide retardation programme

    Ota, Kunio; Alexander, W.R.

    2001-01-01

    The joint Nagra/JNC radionuclide Retardation Programme has now been ongoing for more thean 10 years with the main aim of direct testing of radionuclide transport models for fractured crystalline rocks in as realistic a manner as possible. A large programme of field, laboratory and natural analogue studies has been carried out at the Grimsel Test Site in the central Swiss Alps. The understanding and modelling of both the processes and the structures influencing radionuclide transport in fractured crystalline rocks have matured as has the experimental technology, which has contributed to develop confidence in the applicability of the underlying research models in a repository performance assessment. In this report, the successes and set-backs of this programme are discussed as is the general approach to the thorough testing of the process models and of model assumptions. (author)

  3. Modelling of bentonite-granite solutes transfer from an in situ full-scale experiment to simulate a deep geological repository (Grimsel Test Site, Switzerland)

    Buil, B.; Gomez, P.; Pena, J.; Garralon, A.; Turrero, M.J.; Escribano, A.; Sanchez, L.; Duran, J.M.

    2010-01-01

    Research highlights: → The FEBEX experiment is a 1:1 simulation of a high level waste disposal facility in crystalline rock according to the Spanish radwaste disposal concept. → Solute transfer processes occurrs at the bentonite-granite interface. → An increase of Cl and Na is observed in granitic water of the surrounding of the experiment. → Solute transfer does not affect the sealing and thermo-hydromechanical properties of the engineered barriers. → A diffusive transport of Cl and Na simulated by 1D transport modeling with an effective diffusion coefficient of D e ≅ 5.0 E-11 m 2 /s. - Abstract: The FEBEX experiment is a 1:1 simulation of a high level waste disposal facility in crystalline rock according to the Spanish radwaste disposal concept. This experiment has been performed in a gallery drilled in the underground laboratory Grimsel Test Site (Switzerland). Two boreholes parallel to the FEBEX drift were drilled 20 and 60 cm away from the granite-bentonite interface to provide data on potential bentonite-granite solutes transfer. Periodic sampling and analysis of the major ions showed: (a) the existence of solutes transfer from the bentonite porewater towards the granite groundwater, explaining the Cl - and Na + contents of the latter; (b) that the concentration of the natural tracers coming into the granite groundwater from the bentonite porewater increased over time. This bentonite-granite solutes transfer was modelled in order to predict the increase in the Cl - and Na + concentrations of the granite groundwater. The modelled results seem to confirm that the mechanism of solute migration in this scenario is that of diffusive transport. An effective diffusion coefficient of D e = 5 x 10 -11 m 2 /s was that which best fitted the data obtained.

  4. Investigation of the Quasi-Brittle Failure of Alashan Granite Viewed from Laboratory Experiments and Grain-Based Discrete Element Modeling.

    Zhou, Jian; Zhang, Luqing; Yang, Duoxing; Braun, Anika; Han, Zhenhua

    2017-07-21

    Granite is a typical crystalline material, often used as a building material, but also a candidate host rock for the repository of high-level radioactive waste. The petrographic texture-including mineral constituents, grain shape, size, and distribution-controls the fracture initiation, propagation, and coalescence within granitic rocks. In this paper, experimental laboratory tests and numerical simulations of a grain-based approach in two-dimensional Particle Flow Code (PFC2D) were conducted on the mechanical strength and failure behavior of Alashan granite, in which the grain-like structure of granitic rock was considered. The microparameters for simulating Alashan granite were calibrated based on real laboratory strength values and strain-stress curves. The unconfined uniaxial compressive test and Brazilian indirect tensile test were performed using a grain-based approach to examine and discuss the influence of mineral grain size and distribution on the strength and patterns of microcracks in granitic rocks. The results show it is possible to reproduce the uniaxial compressive strength (UCS) and uniaxial tensile strength (UTS) of Alashan granite using the grain-based approach in PFC2D, and the average mineral size has a positive relationship with the UCS and UTS. During the modeling, most of the generated microcracks were tensile cracks. Moreover, the ratio of the different types of generated microcracks is related to the average grain size. When the average grain size in numerical models is increased, the ratio of the number of intragrain tensile cracks to the number of intergrain tensile cracks increases, and the UCS of rock samples also increases with this ratio. However, the variation in grain size distribution does not have a significant influence on the likelihood of generated microcracks.

  5. Diffusivity database (DDB) for major rocks. Database for the second progress report

    Sato, Haruo

    1999-10-01

    A database for diffusivity for a data setting of effective diffusion coefficients in rock matrices in the second progress report, was developed. In this database, 3 kinds of diffusion coefficients: effective diffusion coefficient (De), apparent diffusion coefficient (Da) and free water diffusion coefficient (Do) were treated. The database, based on literatures published between 1980 and 1998, was developed considering the following points. (1) Since Japanese geological environment is focused in the second progress report, data for diffusion are collected focused on Japanese major rocks. (2) Although 22 elements are considered to be important in performance assessment for geological disposal, all elements and aquatic tracers are treated in this database development considering general purpose. (3) Since limestone, which belongs to sedimentary rock, can become one of the natural resources and is inappropriate as a host rock, it is omitted in this database development. Rock was categorized into 4 kinds of rocks; acid crystalline rock, alkaline crystalline rock, sedimentary rock (argillaceous/tuffaceous rock) and sedimentary rock (psammitic rock/sandy stone) from the viewpoint of geology and mass transport. In addition, rocks around neutrality among crystalline rock were categorized into the alkaline crystalline rock in this database. The database is composed of sub-databases for 4 kinds of rocks. Furthermore, the sub-databases for 4 kinds of the rocks are composed of databases to individual elements, in which totally, 24 items such as species, rock name, diffusion coefficients (De, Da, Do), obtained conditions (method, porewater, pH, Eh, temperature, atmosphere, etc.), etc. are input. As a result of literature survey, for De values for acid crystalline rock, totally, 207 data for 18 elements and one tracer (hydrocarbon) have been reported and all data were for granitic rocks such as granite, granodiorite and biotitic granite. For alkaline crystalline rock, totally, 32

  6. Geochemical study of water-rock interaction processes on geothermal systems of alkaline water in granitic massif; Estudio geoquimico de los procesos de interaccion agua-roca sobre sistemas goetermales de aguas alcalinas en granitoides

    Buil gutierrez, B; Garcia Sanz, S; Lago San Jose, M; Arranz Uague, E; Auque Sanz, L [Universidad de Zaragoza (Spain)

    2002-07-01

    The study of geothermal systems developed within granitic massifs (with alkaline waters and reducing ORP values) is a topic of increasing scientific interest. These systems are a perfect natural laboratory for studying the water-rock interaction processes as they are defined by three main features: 1) long residence time of water within the system, 2) temperature in the reservoir high enough to favour reaction kinetics and finally, 3) the comparison of the chemistry of the incoming and outgoing waters of the system allows for the evaluation of the processes that have modified the water chemistry and its signature, The four geothermal systems considered in this paper are developed within granitic massifs of the Spanish Central Pyrenes; these systems were studied from a geochemical point of view, defining the major, trace and REE chemistry of both waters and host rocks and then characterizing the composition and geochemical evolution of the different waters. Bicarbonate-chloride-sodic and bicarbonate-sodic compositions are the most representative of the water chemistry in the deep geothermal system, as they are not affected by secondary processes (mixing, conductive cooling, etc). (Author)

  7. Rapid extensional unroofing of a granite-migmatite dome with relics of high-pressure rocks, the Podolsko complex, Bohemian Massif

    Žák, J.; Sláma, Jiří; Burjak, M.

    2017-01-01

    Roč. 154, č. 2 (2017), s. 354-380 ISSN 0016-7568 Institutional support: RVO:67985831 Keywords : anisotropy of magnetic susceptibility (AMS) * granite-migmatite dome * exhumation * metamorphic core complex * U-Pb zircon geochronology Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 1.965, year: 2016

  8. Zircon and whole-rock Zr/Hf ratios as markers of the evolution of granitic magmas: Examples from the Teplice caldera (Czech Republic/Germany)

    Breiter, Karel; Škoda, R.

    2017-01-01

    Roč. 111, č. 4 (2017), s. 435-457 ISSN 0930-0708 R&D Projects: GA ČR GA14-13600S Institutional support: RVO:67985831 Keywords : Zr/Hf value * zircon * Teplice caldera * rhyolite * rare-metal granite * Cínovec deposit Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Mineralogy Impact factor: 1.236, year: 2016

  9. Summary of northern Atlantic coastal plain hydrology and its relation to disposal of high-level radioactive waste in buried crystalline rock; a preliminary appraisal

    Lloyd, O.B.; Larson, J.D.; Davis, R.W.

    1985-01-01

    Interpretation of available hydrologic data suggests that some areas beneath the Coastal Plain in the States of Delaware, Maryland, New Jersey, North Carolina, and Virginia might have some potential for the disposal of nuclear waste in crystalline rock that is buried beneath the Coastal Plain sediments. The areas of major interest occur where the top of the basement rock lies between 1,000 and 4,000 feet below sea level, the aquifer(s) immediately above the basement rock are saturated with saline water, confining material overlies the saline water bearing aquifer(s), and groundwater flow in the saline water aquifer(s) can be established. Preliminary data on (1) the distribution and thickness of the lowermost aquifers and confining beds, (2) the distribution of hydraulic conductivity in the lowermost aquifers, (3) estimated hydraulic heads and inferred direction of lateral groundwater flow for 1980, and (4) the distribution of saline water and brine, indicate eastern parts of the study area relatively best meet most of the criteria proposed for sediments that would overlie any potential buried crystalline-rock disposal site.

  10. Geometrical properties of tension-induced fractures in granite

    Sato, Hisashi; Sawada, Atsushi; Yasuhara, Hideaki

    2011-03-01

    Considering a safe, long-term sequestration of energy byproducts such as high level radioactive wastes, it is of significant importance to well-constrain the hydraulic and transport behavior of targeted permeants within fractured rocks. Specifically, fluid flow within low-permeability crystalline rock masses (e.g., granite) is often dominated by transport in through-cutting fractures, and thus careful considerations are needed on the behavior. There are three planes along that granites fail most easily under tension, and those may be identified as the rift, grain, and hardway planes. This anisotropic fabric may be attributed to preferentially oriented microcrack sets contained within intact rock. In this research, geometrical properties of tension-induced fractures are evaluated as listed below; (1) Creation of tension-induced fractures considering the anisotropy clarified by elastic wave measurements. (2) Evaluation of geometrical properties in those fractures characterized by the anisotropy. In the item (1), the three planes of rift, grain and hardway were identified by measuring elastic wave. In the item (2), JRC, variogram, fractal dimension and distributions of elevations in the fracture surfaces were evaluated using digitized data of the fracture surfaces measured via a laser profilometry. Results show that rift planes are less rougher than the other planes of grain and hardway, and grain planes are generically rougher than the other planes of rift and hardway. It was also confirmed that the fracture shape anisotropy was correlated with the direction of the slit which constructed during tensile tests. On the other hand, the tendency peculiar to the direction of slit and granites fail about the estimated aperture distribution from fracture shape was not seen. (author)

  11. Determination of granite rock massif weathering and cracking of surface layers in the oldest parts of medieval mine depending on used mining method

    Lednická, Markéta; Kaláb, Zdeněk

    2016-01-01

    Roč. 61, č. 2 (2016), s. 381-395 ISSN 0860-7001 R&D Projects: GA MŠk(CZ) LO1406; GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : Jeroným Mine * non-destructive testing * granite Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 0.550, year: 2016 http://archiwum.img-pan.krakow.pl/index.php/AMS/article/view/785/692

  12. Modeling of irradiated graphite {sup 14}C transfer through engineered barriers of a generic geological repository in crystalline rocks

    Poskas, Povilas; Grigaliuniene, Dalia, E-mail: Dalia.Grigaliuniene@lei.lt; Narkuniene, Asta; Kilda, Raimondas; Justinavicius, Darius

    2016-11-01

    There are two RBMK-1500 type graphite moderated reactors at the Ignalina nuclear power plant in Lithuania, and they are under decommissioning now. The graphite cannot be disposed of in a near surface repository, because of large amounts of {sup 14}C. Therefore, disposal of the graphite in a geological repository is a reasonable solution. This study presents evaluation of the {sup 14}C transfer by the groundwater pathway into the geosphere from the irradiated graphite in a generic geological repository in crystalline rocks and demonstration of the role of the different components of the engineered barrier system by performing local sensitivity analysis. The speciation of the released {sup 14}C into organic and inorganic compounds as well as the most recent information on {sup 14}C source term was taken into account. Two alternatives were considered in the analysis: disposal of graphite in containers with encapsulant and without it. It was evaluated that the maximal fractional flux of inorganic {sup 14}C into the geosphere can vary from 10{sup −} {sup 11} y{sup −} {sup 1} (for non-encapsulated graphite) to 10{sup −} {sup 12} y{sup −} {sup 1} (for encapsulated graphite) while of organic {sup 14}C it was about 10{sup −} {sup 3} y{sup −} {sup 1} of its inventory. Such difference demonstrates that investigations on the {sup 14}C inventory and chemical form in which it is released are especially important. The parameter with the highest influence on the maximal flux into the geosphere for inorganic {sup 14}C transfer was the sorption coefficient in the backfill and for organic {sup 14}C transfer – the backfill hydraulic conductivity. - Highlights: • Graphite moderated nuclear reactors are being decommissioned. • We studied interaction of disposed material with surrounding environment. • Specifically {sup 14}C transfer through engineered barriers of a geological repository. • Organic {sup 14}C flux to geosphere is considerably higher than inorganic

  13. Climax granite test results

    Ramspott, L.D.

    1980-01-15

    The Lawrence Livermore Laboratory (LLL), as part of the Nevada Nuclear Waste Storage Investigations (NNWSI) program, is carrying out in situ rock mechanics testing in the Climax granitic stock at the Nevada Test Site (NTS). This summary addresses only those field data taken to date that address thermomechanical modeling for a hard-rock repository. The results to be discussed include thermal measurements in a heater test that was conducted from October 1977 through July 1978, and stress and displacement measurements made during and after excavation of the canister storage drift for the Spent Fuel Test (SFT) in the Climax granite. Associated laboratory and field measurements are summarized. The rock temperature for a given applied heat load at a point in time and space can be adequately modeled with simple analytic calculations involving superposition and integration of numerous point source solutions. The input, for locations beyond about a meter from the source, can be a constant thermal conductivity and diffusivity. The value of thermal conductivity required to match the field data is as much as 25% different from laboratory-measured values. Therefore, unless we come to understand the mechanisms for this difference, a simple in situ test will be required to obtain a value for final repository design. Some sensitivity calculations have shown that the temperature field is about ten times more sensitive to conductivity than to diffusivity under the test conditions. The orthogonal array was designed to detect anisotropy. After considering all error sources, anisotropic efforts in the thermal field were less than 5 to 10%.

  14. Boring and Sealing Rock with Directed Energy Millimeter-Waves

    Woskov, P.; Einstein, H. H.; Oglesby, K.

    2015-12-01

    Millimeter-wave directed energy is being investigated to penetrate into deep crystalline basement rock formations to lower well costs and to melt rocks, metals, and other additives to seal wells for applications that include nuclear waste storage and geothermal energy. Laboratory tests have established that intense millimeter-wave (MMW) beams > 1 kW/cm2 can melt and/ or vaporize hard crystalline rocks. In principle this will make it possible to create open boreholes and a method to seal them with a glass/ceramic liner and plug formed from the original rock or with other materials. A 10 kW, 28 GHz commercial (CPI) gyrotron system with a launched beam diameter of about 32 mm was used to heat basalt, granite, limestone, and sandstone specimens to temperatures over 2500 °C to create melts and holes. A calibrated 137 GHz radiometer view, collinear with the heating beam, monitored real time peak rock temperature. A water load surrounding the rock test specimen primarily monitored unabsorbed power at 28 GHz. Power balance analysis of the laboratory observations shows that the temperature rise is limited by radiative heat loss, which would be expected to be trapped in a borehole. The analysis also indicates that the emissivity (absorption efficiency) in the radiated infrared range is lower than the emissivity at 28 GHz, giving the MMW frequency range an important advantage for rock melting. Strength tests on one granite type indicated that heating the rock initially weakens it, but with exposure to higher temperatures the resolidified black glassy product regains strength. Basalt was the easiest to melt and penetrate, if a melt leak path was provided, because of its low viscosity. Full beam holes up to about 50 mm diameter (diffraction increased beam size) were achieved through 30 mm thick basalt and granite specimens. Laboratory experiments to form a seal in an existing hole have also been carried out by melting rock and a simulated steel casing.

  15. Investigations of possibilities to dispose of spent nuclear fuel in Lithuania: a model case. Volume 3, Generic Safety Assessment of Repository in Crystalline Rocks

    Motiejunas, S.; Poskas, P.

    2005-01-01

    In this Volume a generic safety assessment of the repository for spent nuclear fuel in crystalline rock in Lithuania is presented. Modeling of safety relevant radionuclide release from the defected canister and their transport through the near field and far field was performed. Doses to humans due to released radionuclides in the well water were calculated and compared with the dose restrictions existing in Lithuania. For this stage of generic safety assessment only two scenarios were chosen: base scenario and canister defect scenario. KBS-3 concept developed by SKB for disposal of spent nuclear fuel in Sweden was chosen as prototype for repository in crystalline basement in Lithuania. The KBS-3H design with horizontal canister emplacement is proposed as a reference design for Lithuania

  16. 2005 dossier: granite; Dossier 2005: granite

    NONE

    2005-07-01

    This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the geologic disposal of high-level and long-lived radioactive wastes in granite formations. Content: 1 - advantage of granitic formations for the geologic disposal; 2 - containers; 3 - design study of a disposal facility in granitic environment; 4 - understanding and modelling of granite; 5 - description of disposal concepts in granitic environment; 6 - long-term and safety aspects; 7 - conclusion. (J.S.)

  17. Portuguese granites associated with Sn-W and Au mineralizations

    Ana M.R. Neiva

    2002-01-01

    In northern and central Portugal, there are different tin-bearing granites. Most of them are of S-type, others have mixed characteristics of I-type and S-type granites and a few are of I-type. Tin-tungsten deposits are commonly associated with Hercynian tin-bearing S-type granites. Some quartz veins with wolframite are associated with an I-type granite, which has a low Sn content. In suites of tin-bearing S-type granitic rocks, Sn content increases as a function of the degree of fractional cr...

  18. Geochemical characteristics and origin of the Lebowa Granite Suite, Bushveld Complex

    Hill, M.; Barker, F.; Hunter, D.; Knight, R.

    1996-01-01

    The ??? 2052-Ma Lebowa Granite Suite (LGS) represents the culminating phase of an Early Proterozoic magmatic cycle in the Central Transvaal area of the Kaapvaal Province. Following extrusion of at least 200,000 km3 of intermediate to acid volcanics (Rooiberg Felsite), mafic and ultramafic magmas intruded at 2065 Ma to form the Rustenburg Layered Suite (RLS). The LGS includes the Nebo, Makhutso, Bobbejaankop, Lease, and Klipkloof granites. The Nebo Granite intruded the Rooiberg Felsite as sheets up to 4 km thick above the RLS. Smaller stocks of the other granites crosscut the Nebo. We determined major- and trace-element compositions and oxygen, Rb-Sr, and Sm-Nd isotope ratios for samples of: Nebo Granite; Rooiberg Felsite; granophyre and granophyric granite; Makhutso, Bobbejaankop, and Lease granites; and feldspar porphyry from areas throughout the exposed area of the LGS (Dennilton, Verena Balmoral, Enkeldoorn, Sekhukhune Plateau, Zaaiplaats-Potgeitersrus, and Western Transvaal). Coherent floor-to-roof geochemical trends exist in some areas, although it is not possible to model them convincingly. Regional variations in geochemistry exist and likely are related to source variations in the estimated 200,000 km3 of the Nebo Granite sheets. ??18O for the LGS range from +5.9??? to +9.5???; if these are approximate primary magmatic values, pelitic sediments cannot have been an important source for the LGS. The Rb-Sr isotope system has been altered, a finding consistent with previous studies. A mineral isochron for Nebo Granite near Dennilton yields a York regression age of 1995 ?? 99 Ma, with initial 143Nd/144Nd = 0.50978??8 and ???CHUR=-5.12. Samples from the Sekhukhune Plateau have higher 143Nd/144Nd ratios than do Dennilton-area samples, suggesting that the former originated from older or less LREE-enriched sources. We suggest that intrusion of mafic to ultramafic magmas at depth in the continental crust triggered melting of Archean quartzofeldspathic crystalline

  19. Etude de la diagraphie neutron du granite de Beauvoir. Effet neutron des altérations et de la matrice du granite. Calibration granite. Porosité totale à l'eau et porosité neutron Analysis of the Beauvoir Granite Neutron Log. Neutron Effect of Alterations and of the Granite Matrix. Granite Calibration. Total Water Porosity and Neutron Porosity

    Galle C.

    2006-11-01

    carottes (n. Nous montrons que, pour le granite de Beauvoir, l'effet neutron de la matrice est important (en moyenne proche de 7% et ne peut être négligé lorsque l'on mesure des porosités voisines de 0,5% sur carottes. La calibration de l'outil neutron dans le granite et non pas dans des calcaires est d'autre part capitale quant à la précision quantitative des résultats. This article describes the research done on the Beauvoir granite (Echassières GPF 1 borehole, French Massif Central range. The aim of this project was to obtain representative values of the water saturation (n total free water porosity of the Beauvoir granite from PorosityN neutron porosity (BRGM neutron log. The exact knowledge of the porosity of a crystalline block is effectively fundamental to determine its possibilities for being used as a waste storage site. With this goal, neutron logging provides indispensable information concerning the characterization of a porous medium. Our procedure was experimental, and we tried to go more deeply into various problems linked to the use of neutron logging in a granitic rock. Two main factors governed the neutron response : (i the hydrogen concentration of the formation (free water and combined water of various minerals and (ii the presence of absorber elements with a large capture cross-section such as gadolinium, cadmium, boron as well as lithium for the Beauvoir granite. After measuring the Beauvoir granite n total (free water porosity on core samples, we evaluated the combined water content of each sample tested on the basis of fire loss tests on rock powder at 900°C. From the hydrogen atoms volumic concentration, we determined a hydrogen index that we directly converted into the PorosityN(OH- neutron porosity, (by definition, pure water at 20°C has a hydrogen index of 1 which is equivalent to a 100% porosity. For the Beauvoir granite, the matrix combined water represents an average neutron porosity (Table 1 of about 4%. In the second phase, we used

  20. Granite Exfoliation, Cosumnes River Watershed, Somerset, California

    Crockett, I. Q.; Neiss-Cortez, M.

    2015-12-01

    In the Sierra Nevada foothills of California there are many exposed granite plutons within the greater Sierra Nevada batholith. As with most exposed parts of the batholith, these granite slabs exfoliate. It is important to understand exfoliation for issues of public safety as it can cause rock slides near homes, roads, and recreation areas. Through observation, measuring, and mapping we characterize exfoliation in our Cosumnes River watershed community.

  1. Elemental and Sr-Nd isotopic geochemistry of Cretaceous to Early Paleogene granites and volcanic rocks in the Sikhote-Alin Orogenic Belt (Russian Far East): implications for the regional tectonic evolution

    Zhao, Pan; Jahn, Bor-ming; Xu, Bei

    2017-09-01

    The Sikhote-Alin Orogenic Belt in Russian Far East is an important Late Mesozoic to Early Cenozoic accretionary orogen related to the subduction of the Paleo-Pacific Plate. This belt was generated by successive accretion of terranes made of accretionary prisms, turbidite basins and island arcs to the continental margin of northeastern Asia (represented by the Bureya-Jiamusi-Khanka Block) from Jurassic to Late Cretaceous. In order to study the tectonic and crustal evolution of this orogenic belt, we carried out zircon U-Pb dating, and whole-rock elemental and Sr-Nd isotopic analyses on granites and volcanic rocks from the Primorye region of southern Sikhote-Alin. Zircon dating revealed three episodes of granitoid emplacement: Permian, Early Cretaceous and Late Cretaceous to Early Paleogene. Felsic volcanic rocks (mainly rhyolite, dacite and ignimbrite) that overlay all tectonostratigraphic terranes were erupted during 80-57 Ma, postdating the accretionary process in the Sikhote-Alin belt. The Cretaceous-Paleogene magmatism represents the most intense tectonothermal event in the Sikhote-Alin belt. Whole-rock major and trace elemental data show arc-like affinity for granitoids and volcanic rocks, indicating that they were likely generated in a supra-subduction setting. Their initial 87Sr/86Sr ratios range from 0.7048 to 0.7114, and εNd(t) values vary from +1.7 to -3.8 (mostly < 0). Thus, the elemental and Sr-Nd isotopic data suggest that the felsic magmas were generated by partial melting of source rocks comprising mantle-derived juvenile component and recycled crustal component. In addition to the occurrence in the Sikhote-Alin orogenic belt, Cretaceous to Early Paleogene magmatic rocks are also widespread in NE China, southern Korean peninsula, Japanese islands and other areas of Russian Far East, particularly along the coastal regions of the Okhotsk and Bering Seas. These rocks constitute an extended magmatic belt along the continental margin of NE Asia. The

  2. Rock-welding materials for deep borehole nuclear waste disposal.

    Yang, Pin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rodriguez, Mark A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brady, Patrick Vane [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Swift, Peter N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    The concept of deep borehole nuclear waste disposal has recently been proposed. Effective sealing of a borehole after waste emplacement is generally required. In a high temperature disposal mode, the sealing function will be fulfilled by melting the ambient granitic rock with waste decay heat or an external heating source, creating a melt that will encapsulate waste containers or plug a portion of the borehole above a stack of the containers. However, there are certain drawbacks associated with natural materials, such as high melting temperatures, slow crystallization kinetics, the resulting sealing materials generally being porous with low mechanical strength, insufficient adhesion to waste container surface, and lack of flexibility for engineering controls. Here we show that natural granitic materials can be purposefully engineered through chemical modifications to enhance the sealing capability of the materials for deep borehole disposal. This work systematically explores the effect of chemical modification and crystallinity (amorphous vs. crystalline) on the melting and crystallization processes of a granitic rock system. A number of engineered granitic materials have been obtained that have decreased melting points, enhanced viscous densification, and accelerated recrystallization rates without compromising the mechanical integrity of the materials.

  3. Analysis of the possibility of isolation of radioactive wastes of Chernobyl nuclear power plant into the deep drills of the Korosten crystalline rocks

    Shestopalov, V.; Kedrovsky, O.; Shishits, I.

    1996-01-01

    The aim of the offered research: - investigation and proving the possibility to isolate the radioactive wastes (RAW), that were created as a result of the Chernobyl accident, its operation, and shutting down, by placing the wastes into the chinks of the depth up to 4 km. The chinks are supposed to be made in the crystalline rocks of the Korosten massif located near of the Chernobyl NPP. - developing of the basis of the technology and fulfilling the designing work for isolation the RAW in the deep chinks. The basic aims of the researches of the project are the following : Finding out the location of a suitable place. The Ukraine plate's territory (having non-deep occurrences of the crystalline rocks that are minimally subjected to the tectonic destroying), near of the Chernobyl NPP, would be investigated. To solve the problem , the decoding of the aero- and space-photos, geophysical and indicating works, testing drilling of non-deep chinks, and testing works in it have to be done. So, during of the carrying out the project , the following points would be developed: - the geological grounds for creating the RAW isolating system in the deep chinks (taking the conditions at the Nuclear Power Plant), - the best design of the deep chink, - the technology of isolating the RAW in the deep chinks, - the requirements on the monitoring, - the estimations of the ecological safety and efficiency of the chink type systems for RAW isolating

  4. Preserved magnetic fabrics vs. annealed microstructures in the syntectonic recrystallised George granite, South Africa

    Ferré, E. C.; Améglio, L.

    2000-08-01

    The Saldanian basement of the Cape Fold Belt of South Africa outcrops in the Kaaimans inlier with granite plutons intruded in low-grade pelitic and quartzitic metasediments around 535 Ma. New field data support a ubiquitous Saldanian top-to-the-north thrust kinematics coeval with granite emplacement with no substantial Cape tectonic overprint. The granites and their contact aureoles display both synkinematic and post-kinematic fabrics. This and the high strain zone commonly observed all along the contact between the Kaaimans inlier and the Cape Fold Belt, suggest a structural decoupling between the basement and its cover. Microstructures in the Kaaimans inlier and in the George pluton establish a post-kinematic, pervasive and thermal overprint of Saldanian age. Granites and country rocks record a medium-temperature/high-strain deformation phase followed by a strong low-temperature/static recrystallisation. Two sets of andalusite porphyroblasts occur systematically in the contact aureoles of the studied plutons and cannot be explained by successive magmatic pulses. The granites, studied by the Anisotropy of Magnetic Susceptibility (AMS) technique, are paramagnetic (20law) and on intrinsic mineral susceptibilities. The magnetic foliations and lineations are homogeneous throughout the George pluton and are consistent with field structures. The AMS results mainly from the magneto-crystalline anisotropy of biotite and from its lattice preferred orientation (LPO) in the rock. The magnetic fabric reveals the biotite subfabrics that had been acquired before static recrystallisation and which was not modified by the subsequent thermal metamorphic event. The magnetic fabric therefore preserves the emplacement-related deformation fabric.

  5. Surveying for migration pathways in the granitic rock using nuclear track detectors, autoradiography and digital image analysis as an aid to construct the basis for heterogeneous diffusion modeling

    Kemppainen, M.; Oila, E.; Siitari-Kauppi, M.

    2001-01-01

    Radioelement migration within a rock matrix under natural long-term conditions is a complex process controlled by various parameters. Pure physical parameters such as porosity, hydraulic conductivity and diffusivity are usually sufficient to describe transport in well-defined laboratory systems. In natural rock matrices transport is influenced by physical pore properties such as pore size distribution, connectivity, tortuosity, constrictivity and petrological and chemical nature and charge on the fluid-rock interface. The overall characterization of heterogeneous rock structures is needed for the accurate heterogeneous diffusion modeling. Here we describe a method for the detection of α-particles from uranium in cm-scale rock samples based on the analysis of the tracks formed in organic polymer, CR-39. On the other hand the uranium tracks were compared with the migration pathways and porosity distribution produced with the 14 C-polymethylmethacrylate impregnation method ( 14 C-PMMA). For analyzing mineral specific uranium occurrence and porosities the staining methods were used to produce the mineral map of the rock sample. Digital image analysis techniques were applied to the different cm-scale pictures of rock samples. Scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDS) were performed in order both to study the pore apertures of grain boundaries and fissures in greater detail and to detect the uranium phases. The high uranium content was found to be congruent with the porous mineral phases; altered plagioclase and biotite grains, and the intra- and intergranular fissures detected with the 14 C-PMMA technique. Plenty of microfractures transsecting potassium feldspar and quartz grains were filled with calcite together with precipitated uranium. Copyright (2001) Material Research Society

  6. Application of the continuously-yielding joint model for studying disposal of high-level nuclear waste in crystalline rock

    Hakala, M.; Johansson, E.; Simonen, A.

    1993-04-01

    The non-linear Continuously-Yielding (CY) joint model and its use in numerical analyses of a nuclear waste repository are studied in the report. On major advantage of using CY-model is that laboratory test results, if available, can directly be used in analyses thus reducing uncertainties about joint input parameters. The new testing machine MTS-815 of Helsinki University of Technology was used to determine the joint behaviour of some granitic joints from the depth of 400-600 m below the ground surface. The procedure for triaxial joint tests was refined during this work. Two programs called NormFit and SherFit were developed and tested to determine the best fit parameter values for CY-model from laboratory test results

  7. Exploration of the enhanced geothermal system (EGS) potential of crystalline rocks for district heating (Elbe Zone, Saxony, Germany)

    Förster, Andrea; Förster, Hans-Jürgen; Krentz, Ottomar

    2018-01-01

    This paper addresses aspects of a baseline geothermal exploration of the thermally quiescent Elbe Zone (hosting the cities of Meissen and Dresden) for a potential deployment of geothermal heat in municipal heating systems. Low-permeable to impermeable igneous and metamorphic rocks constitute the major rock types at depth, implying that an enhanced geothermal system needs to be developed by creating artificial flow paths for fluids to enhance the heat extraction from the subsurface. The study includes the development of geological models for two areas on the basis of which temperature models are generated at upper crustal scale. The models are parameterized with laboratory-measured rock thermal properties (thermal conductivity k, radiogenic heat production H). The uncertainties of modelled temperature caused by observed variations of k and H and inferred mantle heat flow are assessed. The study delineates highest temperatures within the intermediate (monzonite/syenite unit) and mafic rocks (diorite/monzodiorite unit) forming the deeper portions of the Meissen Massif and, specifically for the Dresden area, also within the low-metamorphic rocks (slates/phyllites/quartzites) of the Elbtalschiefergebirge. Boreholes 3-4 km deep need to be drilled to reach the envisioned economically favourable temperatures of 120 °C. The metamorphic and mafic rocks exhibit low concentrations of U and Th, thus being advantageous for a geothermal use. For the monzonite/syenite unit of high heat production ( 6 µW m-3) in the Meissen Massif, the mobilization of Th and U into the geothermal working fluid is assumed to be minor, although their various radioactive decay products will be omnipresent during geothermal use.

  8. High cesium concentrations in groundwater in the upper 1.2 km of fractured crystalline rock - Influence of groundwater origin and secondary minerals

    Mathurin, Frédéric A.; Drake, Henrik; Tullborg, Eva-Lena; Berger, Tobias; Peltola, Pasi; Kalinowski, Birgitta E.; Åström, Mats E.

    2014-05-01

    Dissolved and solid phase cesium (Cs) was studied in the upper 1.2 km of a coastal granitoid fracture network on the Baltic Shield (Äspö Hard Rock Laboratory and Laxemar area, SE Sweden). There unusually high Cs concentrations (up to 5-6 μg L-1) occur in the low-temperature (single and primary control of dissolved Cs in these systems. The high Cs concentrations in the saline groundwater is ascribed to long-term weathering of minerals, primarily Cs-enriched fracture coatings dominated by illite and mixed-layer clays and possibly wall rock micaceous minerals. The high Cs concentrations in the groundwater of marine origin are, in contrast, explained by relatively fast cation exchange reactions. As indicated by the field data and predicted by 1D solute transport modeling, alkali cations with low-energy hydration carried by intruding marine water are capable of (NH4+ in particular and K+ to some extent) replacing Cs+ on frayed edge (FES) sites on illite in the fracture coatings. The result is a rapid and persistent (at least in the order of decades) buildup of dissolved Cs concentrations in fractures where marine water flows downward. The identification of high Cs concentrations in young groundwater of marine origin and the predicted capacity of NH4+ to displace Cs from fracture solids are of particular relevance in the disposal of radioactive nuclear waste deep underground in crystalline rock.

  9. Use of the 14C-PMMA and He-gas methods to characterise excavation disturbance in crystalline rock

    Autio, J.; Kirkkomaeki, T.; Siitari-Kauppi, M.; Timonen, J.; Laajalahti, M.; Aaltonen, T.; Maaranen, J.

    1999-04-01

    Characterisation of the excavation disturbance caused by boring of experimental full-scale deposition holes in the Research Tunnel at Olkiluoto was carried out successfully by using two novel methods; the 14 C-PMMA and He-gas methods, which were modified and applied for the first time in this type of study. The experience obtained implies that the techniques are feasible and can be used to study similar types of rock excavation disturbance such as that caused by boring with mini discs, a technique which will be used in the underground Hard Rock Laboratory at Aespoe during late 1998 and early 1999. Both of the measurement methods have been in continuous use and the work has included development of both the measuring and interpretation techniques. Use of the 14 C-PMMA method is suggested for studies of rock structure and the spatial distribution of porosity. The 14 C-PMMA method also provides quantitative information about nanometer-range porosity which is beyond the scope of most standard methods of microscopic investigation. The use of He-gas methods are proposed for determining the diffusion coefficient, permeability and complementary porosity of rock samples taken from the disturbed zone. (orig.)

  10. Two-mica granites of northeastern Nevada.

    Lee, D.E.; Kistler, R.W.; Friedman, I.; Van Loenen, R. E.

    1981-01-01

    The field settings are described and analytical data are presented for six two-mica granites from NE Nevada. High delta 18O and 87Sr/86Sr values indicate that all are S-type granite, derived from continental crust. The major element chemistry and accessory mineral contents of these rocks also are characteristic of S-type granites. Chemical, X ray, and other data are presented for the micas recovered from these granites. The muscovites are notably high in Fe2O3, FeO, and MgO. Except for one hydrobiotite, each of the biotites has an MgO content near 6.0 wt%. Two different types of two-mica granites are recognized in the area of this study. One type is distinguished by the presence of many biotite euhedra within muscovite phenocrysts and by an unusual suite of accessory minerals completely devoid of opaque oxides. This type probably resulted from anatexis of late Precambrian argillites under conditions of relatively low oxygen fugacity, along a line that roughly coincides with the westward disappearance of continental basement. In the other textural type of two-mica granite the micas are equigranular and there is a greater variety of accessory minerals. The magmatic evolution of this type also appears to reflect the influence of late Precambrian argillites; there may be age differences between the two types of two-mica granites.-Author

  11. Review of potential host rocks for radioactive waste disposal in the southeast United States-Southern Piedmont subregion

    1980-10-01

    A literature study was conducted on the geology of the Southern Piedmont province in the states of Maryland, Virginia, North Carolina, South Carolina, and Georgia. The purpose was to identify geologic areas potentially suitable for containment of a repository for the long-term isolation of solidified radioactive waste. The crystalline rocks of the Southern Piedmont province range in age from Precambrian to Paleozoic, and are predominantly slates, phyllites, argillites, schists, metavolcanics, gneisses, gabbros, and granites. These rock units were classified as either favorable, potentially favorable, or unfavorable as potential study areas based on an evaluation of the geologic, hydrologic, and geotechnical characteristics. No socio-economic factors were considered. Rocks subjected to multiple periods of deformation and metamorphism, or described as highly fractured, or of limited areal extent were generally ranked as unfavorable. Potentially favorable rocks are primarily the high-grade metamorphic gneisses and granites. Sixteen areas were classified as being favorable for additional study. These areas are primarily large igneous granite plutons as follows: the Petersburg granite in Virginia; the Rolesville-Castallia, Churchland, and Landis plutons in North Carolina; the Liberty Hill, Winnsboro, and Ogden plutons in South Carolina; and the Siloam, Elberton, and six unnamed granite plutons in Georgia

  12. Hydraulic testing in granite using the sinusoidal variation of pressure

    Black, J.H.; Holmes, D.C.; Noy, D.J.

    1982-09-01

    Access to two boreholes at the Carwynnen test site in Cornwall enabled the trial of a number of innovative approaches to the hydrogeology of fractured crystalline rock. These methods ranged from the use of seisviewer data to measure the orientation of fractures to the use of the sinusoidal pressure technique to measure directional hydraulic diffusivity. The testing began with a short programme of site investigation consisting of borehole caliper and seisviewer logging followed by some single borehole hydraulic tests. The single borehole hydraulic testing was designed to assess whether the available boreholes and adjacent rock were suitable for testing using the sinusoidal method. The main testing methods were slug and pulse tests and were analysed using the fissured porous medium analysis proposed in Barker and Black (1983). Derived hydraulic conductivity (K) ranged from 2 x 10 -12 m/sec to 5 x 10 -7 m/sec with one near-surface zone of high K being perceived in both boreholes. The results were of the form which is typical of fractured rock and indicated a combination of high fracture frequency and permeable granite matrix. The results are described and discussed. (author)

  13. Comparison of different digital elevation models and satellite imagery for lineament analysis: Implications for identification and spatial arrangement of fault zones in crystalline basement rocks of the southern Black Forest (Germany)

    Meixner, J.; Grimmer, J. C.; Becker, A.; Schill, E.; Kohl, T.

    2018-03-01

    first order results of the spatial arrangement of critically stressed faults in crystalline basement rocks.

  14. 2005 dossier: granite

    2005-01-01

    This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the geologic disposal of high-level and long-lived radioactive wastes in granite formations. Content: 1 - advantage of granitic formations for the geologic disposal; 2 - containers; 3 - design study of a disposal facility in granitic environment; 4 - understanding and modelling of granite; 5 - description of disposal concepts in granitic environment; 6 - long-term and safety aspects; 7 - conclusion. (J.S.)

  15. The research frontier and beyond: granitic terrains

    Twidale, C. R.

    1993-07-01

    been subjected will be more and more appreciated as offering explanations for a wide range of granite forms, major and minor, ancient and recent. In particular, investigations of rock strain, including gravitational loading, at a variety of scales, and especially as it influences fracture patterns and susceptibility to weathering, will assume a prime importance in the explanation of granitic landforms and landscapes. Finally, there as genuine hopes that the close dating of surfaces and weathering events will allow structural and process studies to be placed in their chronilogical contexts. New techniques and observations will prove important to advances in the understanding of granitic forms, but, as in other areas of geomorphological endeavour, fresh perceptions, different linkages and new ideas are critical.

  16. Studies of thermal and radiation effects on water-rock systems related to envisaged isolation of high level radioactive wastes in crystalline formations of the Ukrainian shield (Ukraine)

    Litovchenko, A.; Kalinichenko, E.; Ivanitsky, V.; Bagmut, M.; Plastinina, M.; Zlobenko, B.

    2000-01-01

    In this work there are presented the general data on the study of thermal and radiation effects in minerals separated from rocks of the Ukrainian shield. These minerals (quartz, feldspar, amphiboles, apatite, biotite, kaolinite, etc.), exposed by doses 10 4 , 10 6 , 10 8 Gy by Co 60 source, were studied by a complex of physical methods. Special attention was given to the study of radiation defects formation (electron-hole paramagnetic centres, OH- groups destruction, changes in a charge state of ions) in a mineral structure. The mentioned radiation defects were used in the extrapolation method. The connection between structural peculiarities of minerals (containing uranium and thorium) and processes of their metamyctization are considered. It is demonstrated that the minerals, which have large channels or interlayer spaces in their structure, as a rule, are not metamyct. Using the spectroscopic methods of the extrapolation it is shown that the crystalline massifs, which do not have detectable amounts of hydroxyl containing minerals (biotite, amphibole, etc.) and ions Fe 2- , are perspective for long-lived radioactive wastes (RAW) dumping. As it follows from obtained results, the rocks, containing minerals with OH- groups and gas-liquid inclusions, should be considered as the 'mineral-water' system. (author)

  17. A global sensitivity analysis of two-phase flow between fractured crystalline rock and bentonite with application to spent nuclear fuel disposal.

    Dessirier, Benoît; Frampton, Andrew; Jarsjö, Jerker

    2015-11-01

    Geological disposal of spent nuclear fuel in deep crystalline rock is investigated as a possible long term solution in Sweden and Finland. The fuel rods would be cased in copper canisters and deposited in vertical holes in the floor of deep underground tunnels, embedded within an engineered bentonite buffer. Recent experiments at the Äspö Hard Rock Laboratory (Sweden) showed that the high suction of unsaturated bentonite causes a de-saturation of the adjacent rock at the time of installation, which was also independently predicted in model experiments. Remaining air can affect the flow patterns and alter bio-geochemical conditions, influencing for instance the transport of radionuclides in the case of canister failure. However, thus far, observations and model realizations are limited in number and do not capture the conceivable range and combination of parameter values and boundary conditions that are relevant for the thousands of deposition holes envisioned in an operational final repository. In order to decrease this knowledge gap, we introduce here a formalized, systematic and fully integrated approach to study the combined impact of multiple factors on air saturation and dissolution predictions, investigating the impact of variability in parameter values, geometry and boundary conditions on bentonite buffer saturation times and on occurrences of rock de-saturation. Results showed that four parameters consistently appear in the top six influential factors for all considered output (target) variables: the position of the fracture intersecting the deposition hole, the background rock permeability, the suction representing the relative humidity in the open tunnel and the far field pressure value. The combined influence of these compared to the other parameters increases as one targets a larger fraction of the buffer reaching near-saturation. Strong interaction effects were found, which means that some parameter combinations yielded results (e.g., time to

  18. A coupled mechanical-hydrological investigation of crystalline rocks: Annual technical progress report, proposed test matrix, and preliminary results

    Bastian, R.J.; Voss, C.F.; Apted, M.J.; Shotwell, L.R.

    1988-02-01

    This report reviews the Fracture Flow Behavior in Rock Study being performed at the Pacific Northwest Laboratory. The study's objective is to determine the feasibility of predicting mechanical-hydrological behavior of natural rock fractures by accurately characterizing fracture surface topography and mineralization. A laboratory-scale facility is currently being used to ensure optimum control of variables. Devising a technique to study small-scale samples is the first step to understanding the complex coupled processes encountered in geomechanics and hydrology. The major accomplishments during fiscal year 1987 were initial development of the innovative testing method, identification of appropriate specimens, substantial renovation to the facility, completion of several sets of experiments, and procurement of hardware components for a laser-imaging device used to characterize fracture surfaces. A complete set of preliminary results and findings is presented in this report. These results, gathered from a basalt core with a natural fracture, have demonstrated that the methodology is valid, and definite trends in the data are readily apparent. 10 refs., 14 figs., 1 tab

  19. Consequences of using crushed crystalline rock as ballast in KBS-3 tunnels instead of rounded quartz particles

    Push, R.

    1995-02-01

    The basic question has been whether such replacement alters the hydraulic conductivity and compressibility as well as expandability and also if the physical and chemical stabilities are altered. The key factor is the microstructural constitution of the bentonite/ballast mixtures, which is primarily controlled by the grain size distribution of the ballast. The compact ability of backfills with quartz sand (SB) is higher than that of backfills with crushed rock as ballast (RB). The physical stability of RB backfills in terms of piping and erosion resistance will be somewhat lower than that of SB backfills. The chemical stability is practically independent of whether the ballast is pure quartz or rock with K-bearing minerals because the temperature in the backfill will be too low to yield significant smectite to illite conversion in the short heating period. In order to reach the same densities of SB and RB backfills, which turn out to give fairly similar physical properties, the latter backfills need more effective compaction or, alternatively, a higher bentonite content. It is estimated that if the bentonite content in RB backfills is not increased while the density is enhanced to what is achievable, these backfills will serve equally well as SB backfills with the densities implied by the basic KBS-3 concept. 23 refs, 27 figs, 7 tabs

  20. Consequences of using crushed crystalline rock as ballast in KBS-3 tunnels instead of rounded quartz particles

    Push, R [Clay Technology AB (Sweden)

    1995-02-01

    The basic question has been whether such replacement alters the hydraulic conductivity and compressibility as well as expandability and also if the physical and chemical stabilities are altered. The key factor is the microstructural constitution of the bentonite/ballast mixtures, which is primarily controlled by the grain size distribution of the ballast. The compact ability of backfills with quartz sand (SB) is higher than that of backfills with crushed rock as ballast (RB). The physical stability of RB backfills in terms of piping and erosion resistance will be somewhat lower than that of SB backfills. The chemical stability is practically independent of whether the ballast is pure quartz or rock with K-bearing minerals because the temperature in the backfill will be too low to yield significant smectite to illite conversion in the short heating period. In order to reach the same densities of SB and RB backfills, which turn out to give fairly similar physical properties, the latter backfills need more effective compaction or, alternatively, a higher bentonite content. It is estimated that if the bentonite content in RB backfills is not increased while the density is enhanced to what is achievable, these backfills will serve equally well as SB backfills with the densities implied by the basic KBS-3 concept. 23 refs, 27 figs, 7 tabs.

  1. Multi-azimuth Anisotropic Velocity Measurements in Fractured Crystalline Rock From the International Continental Drilling Program Outokumpu Borehole, Finland

    Schijns, H.; Duo, X.; Heinonen, S.; Schmitt, D. R.; Kukkonen, I. T.; Heikkinen, P.

    2008-12-01

    A high resolution seismic survey consisting of a multi-depth multi-azimuth VSP, a zero-offset VSP and a reflection/refraction survey was conducting in May, 2006, near the town of Outokumpu, Finland, using the International Continental Scientific Drilling Program 2.5 km deep fully cored scientific borehole. The survey was undertaken in order to create an anisotropic velocity model for future micro-seism studies as well as to provide a higher resolution reflection profile through the area than was previously available. The seismic survey high frequency seismic vibrator as a source, employing 8 s linear taper sweeps from 15-250 Hz at 20 m shot spacing. Receivers were 14 Hz single component geophones on the surface and a three component geophone downhole. The walk-away VSP included measurements over two azimuths with the receiver at depths of 1000, 1750 and 2500 m, while the zero-offset VSP used a 2 m depth increment. Surface geophones were located along the same seismic lines as employed in the walk-away VSP and were nominally 4 m apart. The survey area is located on the Fennoscandian shield, and the glacial history of the area required significant static corrections to account for the variable overburden overlying the mica-rich schist and pegmatitic granite composing the bedrock. These were calculated using travel-time inversion of the refraction data and were applied to the walk-away VSP and reflection profiles, significantly improving the quality of both. Anisotropic velocity analysis was performed using a plane-wave decomposition of the processed walk-away VSP. The maximum anisotropy was observed in the walk-away VSPs along the Southeastern azimuth, with the P-wave phase velocity ranging from 5330-5950 m/s between 50-1000 m in depth, and up to 6150 m/s between 1000-1750 m in depth. Shear wave splitting was observed in the Northeastern direction. Preliminary analysis of the zero-offset VSP has revealed shown good agreement with the relevant portions of the

  2. The instrumental neutron-activation analysis of granites from the Bushveld Complex

    Watterson, J.I.W.

    1978-01-01

    Three methods of instrumental neutron-activation analysis, 14MeV, reactor thermal, and reactor epithermal, are compared for the analysis of granites form the Bushveld Complex. A total of 34 elements can be determined in the granites by these methods. Samples from the Zaaiplaats area were analysed by thermal neutron activation, and 22 elements were determined in all of them. These elements were used to distinguish between the mineralized Bobbejaankop and Lease granites and the Main granite by the use of multivariate statistics. The Bobbejaankop granite appears as a more-differentaited rock carrying greater amounts of the incompatible elements than does the Main granite [af

  3. Parameters and a magnitude moment relationship from small earthquakes observed during hydraulic fracturing experiments in crystalline rocks

    Pearson, C.

    1982-04-01

    Using source parameters estimated from seismic spectra and magnitudes estimated from coda lengths, we demonstrate that the log-linear relationship between moment and magnitude holds for events with magnitudes as low as -6. Using, as a data set, events induced by hydraulic fracturing experiments at the Fenton Hill, New Mexico, Hot Dry Rock (HDR) geothermal site, we find that the relationship between magnitude M and seismic moment (Mo) is log (Mo) = 17.27+0.77 M Moreover, the linear relationship between seismic moment and source radius (r) holds for the Fenton Hill microearthquakes. Analyses of the Fenton Hill data yield the following relationship. log (r) = 2.28+0.19 log (Mo)

  4. Characterization of fractures and flow zones in a contaminated crystalline-rock aquifer in the Tylerville section of Haddam, Connecticut

    Johnson, Carole D.; Kiel, Kristal F.; Joesten, Peter K.; Pappas, Katherine L.

    2016-10-04

    The U.S. Geological Survey, in cooperation with the Connecticut Department of Energy and Environmental Protection, investigated the characteristics of the bedrock aquifer in the Tylerville section of Haddam, Connecticut, from June to August 2014. As part of this investigation, geophysical logs were collected from six water-supply wells and were analyzed to (1) identify well construction, (2) determine the rock type and orientation of the foliation and layering of the rock, (3) characterize the depth and orientation of fractures, (4) evaluate fluid properties of the water in the well, and (5) determine the relative transmissivity and head of discrete fractures or fracture zones. The logs included the following: caliper, electromagnetic induction, gamma, acoustic and (or) optical televiewer, heat-pulse flowmeter under ambient and pumped conditions, hydraulic head data, fluid electrical conductivity and temperature under postpumping conditions, and borehole-radar reflection collected in single-hole mode. In a seventh borehole, a former water-supply well, only caliper, fluid electrical conductivty, and temperature logs were collected, because of a constriction in the borehole.This report includes a description of the methods used to collect and process the borehole geophysical data, the description of the data collected in each of the wells, and a comparison of the results collected in all of the wells. The data are presented in plots of the borehole geophysical logs, tables, and figures. Collectively these data provide valuable characterizations that can be used to improve or inform site conceptual models of groundwater flow in the study area.

  5. Differentiating pedogenesis from diagenesis in early terrestrial paleoweathering surfaces formed on granitic composition parent materials

    Driese, S.G.; Medaris, L.G.; Ren, M.; Runkel, Anthony C.; Langford, R.P.

    2007-01-01

    Unconformable surfaces separating Precambrian crystalline basement and overlying Proterozoic to Cambrian sedimentary rocks provide an exceptional opportunity to examine the role of primitive soil ecosystems in weathering and resultant formation of saprolite (weathered rock retaining rock structure) and regolith (weathered rock without rock structure), but many appear to have been affected by burial diagenesis and hydrothermal fluid flow, leading some researchers to discount their suitability for such studies. We examine one modern weathering profile (Cecil series), four Cambrian paleoweathering profiles from the North American craton (Squaw Creek, Franklin Mountains, Core SQ-8, and Core 4), one Neoproterozoic profile (Sheigra), and one late Paleoproterozoic profile (Baraboo), to test the hypothesis that these paleoweathering profiles do provide evidence of primitive terrestrial weathering despite their diagenetic and hydrothermal overprinting, especially additions of potassium. We employ an integrated approach using (1) detailed thin-section investigations to identify characteristic pedogenic features associated with saprolitization and formation of well-drained regoliths, (2) electron microprobe analysis to identify specific weathered and new mineral phases, and (3) geochemical mass balance techniques to characterize volume changes during weathering and elemental gains and losses of major and minor elements relative to the inferred parent materials. There is strong pedogenic evidence of paleoweathering, such as clay illuviation, sepic-plasmic fabrics, redoximorphic features, and dissolution and alteration of feldspars and mafic minerals to kaolinite, gibbsite, and Fe oxides, as well as geochemical evidence, such as whole-rock losses of Na, Ca, Mg, Si, Sr, Fe, and Mn greater than in modern profiles. Evidence of diagenesis includes net additions of K, Ba, and Rb determined through geochemical mass balance, K-feldspar overgrowths in overlying sandstone sections, and

  6. Explosion Amplitude Reduction due to Fractures in Water-Saturated and Dry Granite

    Stroujkova, A. F.; Leidig, M.; Bonner, J. L.

    2013-12-01

    Empirical observations made at the Semipalatinsk Test Site suggest that nuclear tests in the fracture zones left by previous explosions ('repeat shots') show reduced seismic amplitudes compared to the nuclear tests in virgin rocks. Likely mechanisms for the amplitude reduction in the repeat shots include increased porosity and reduced strength and elastic moduli, leading to pore closing and frictional sliding. Presence of pore water significantly decreases rock compressibility and strength, thus affecting seismic amplitudes. A series of explosion experiments were conducted in order to define the physical mechanism responsible for the amplitude reduction and to quantify the degree of the amplitude reduction in fracture zones of previously detonated explosions. Explosions in water-saturated granite were conducted in central New Hampshire in 2011 and 2012. Additional explosions in dry granite were detonated in Barre, VT in 2013. The amplitude reduction is different between dry and water-saturated crystalline rocks. Significant reduction in seismic amplitudes (by a factor of 2-3) in water-saturated rocks was achieved only when the repeat shot was detonated in the extensive damage zone created by a significantly larger (by a factor of 5) explosion. In case where the first and the second explosions were similar in yield, the amplitude reduction was relatively modest (5-20%). In dry rocks the amplitude reduction reached a factor of 2 even in less extensive damage zones. In addition there are differences in frequency dependence of the spectral amplitude ratios between explosions in dry and water-saturated rocks. Thus the amplitude reduction is sensitive to the extent of the damage zone as well as the pore water content.

  7. Solute transport in crystalline rocks at Äspö — II: Blind predictions, inverse modelling and lessons learnt from test STT1

    Jakob, Andreas; Mazurek, Martin; Heer, Walter

    2003-03-01

    laboratory data. The extracted Kd values for the weakly sorbing tracers are larger than Swedish laboratory data by a factor of 25-60, but agree within a factor of 3-5 for the more strongly sorbing nuclides. The reason for the inconsistency concerning Kds is the use of fresh granite in the laboratory studies, whereas tracers in the field experiments interact only with fracture fault gouge and to a lesser extent with cataclasite both being mineralogically very different (e.g. clay-bearing) from the intact wall rock.

  8. Petrographic and mineralogical features of the uraniferous pink granites in the north eastern desert of egypt

    Atawiya, M.Y.; Salman, A.B.; El-Bayyomi, R.M.

    1998-01-01

    The present work is concerned with the petrological, mineralogical and geochemical studies of some uranium bearing younger granites in the north eastern desert of egypt particularly Gebel Gattar area. The area around Gebel Gattar comprises the following rock units (starting from the oldest): meta volcanic, diorite-grano-diorite complex- Dokhan volcanics- Hammamat sediments, younger granites and dykes. The most significant structural features are represented by NNE-ENE dominantly trending faults and joints. Petrographicaly, the pink granites are divided into normal and mineralized (uraniferous) granites. Normal granites are classified into three types; a) leucocratic perthitic granite, b) hornblende- biotite perthitic granite and c) two feldspars perthitic granite. Mineralized granites are sheared, deformed, pinkish brown in colour and strongly altered. A remarkable secondary uranium mineralization has been recorded along fault and fracture zones

  9. AMS studies in Portuguese variscan granites

    Sant'Ovaia, Helena; Martins, Helena; Noronha, Fernando

    2014-05-01

    A large volume of Variscan granitic rocks outcrop in Central Iberian Zone which are well documented concerning geological mapping, petrography and geochemistry but whose magnetic characteristics and fabric remain unknown. In this study we summarize the available AMS data from approximately 644 sampling stations (5152 samples) on different massifs of Variscan Portuguese granites. Despite their different geological, petrographic and geochemical characteristics, magnetic susceptibility (K) values obtained for the majority of the studied granites range from 15 to 300 × 10-6 SI. The dominant paramagnetic behaviour of the granite bodies reflects the presence of ilmenite as the main iron oxide. This feature indicates the reduced conditions involved in the granite melt formation during the Variscan orogeny. The two-mica granites show K values ranging between 15 to 70 × 10-6 SI which are lower than values displayed by the biotite-rich facies scattered within the interval of 70 and 300 × 10-6 SI. The magnetite-bearing granites are scarce but represented in Lavadores, Gerês and Manteigas. Even so, only the Lavadores body could be considered as a true magnetite-type granite (K >3.0 × 10-3 SI) in face of its K, comprised between 1550 and 19303 × 10-6 SI. Magnetic anisotropy can be used as a "marker" for the deformation experienced by granite mushes during their crustal emplacement and further cooling. Magnetic anisotropy can thus be correlated with the finite deformation of a rock, as record by mineral fabrics. Post-tectonic granites, such as those from Vila Pouca de Aguiar, Pedras Salgadas, Caria, Vila da Ponte, Chaves and Lamas de Olo, have a magnetic anisotropy <2.5% which corresponds to a deformation hardly visible to the naked eye. Nevertheless, at microscopic scale, these granites display almost ubiquitous magmatic to submagmatic microstructures (rare wavy extinction in quartz, erratic subgrain boundaries in quartz and, eventually, folded or kinked biotites). For

  10. Characterization of weathering profile in granites and ...

    and Environmental Engineering (2iE), 01 BP 594 Ouagadougou, Burkina Faso. 2Laboratoire ...... A 1984 Isotope studies as a final stage in groundwater investigations on ... of the hydrogeology of deeply weathered crystalline rock: Evidence ...

  11. Application of streaming potential method for detection of fractures in granitic rock. part 2; Kamaishi kozan ni okeru ryutai ryudo den`iho tekiyo shiken. 2

    Negi, T; Yoneda, Y [Nittetsu Mining Co. Ltd., Tokyo (Japan); Senba, T [Power Reactor and Nuclear Fuel Development Corp., Tokyo (Japan)

    1997-10-22

    Streaming potential method has been applied in the Kamaishi Mine. In FY 1995, self-potential (SP) was monitored on the wall of gallery by varying the pressure in the well with open/close operation of the mouth of well having spring water, which was drilled from the gallery. It was confirmed that SP changes remarkably at the wall having a great number of fractures with spring water. It was considered that the change in SP is due to the streaming potential generated by the flowing underground water from the gallery side to the fractures in the well. In this paper, this continuity of the wall of gallery and the fractures in the well is estimated. In the present tests, SP changes were observed at walls of surrounding galleries by varying the pressure in the well with open/close operation of the mouth of borehole at various drilling depths during drilling of borehole. As a result, SP changes were observed at the wall of gallery when reaching to the depth with increased spring water. The results agreed well with the test results conducted at the same field in FY 1995. It was confirmed that the streaming potential method is a useful method for grasping the hydraulic continuity in the rocks. 2 refs., 9 figs.

  12. The long-term strength and deformation properties of crystalline rock in a high level nuclear waste repository

    Tuokko, T.

    1990-12-01

    The time-dependent phenomena which can affect the strength and deformation properties of hard crystal line rock are clarified. Suitable measuring methods for field conditions are also summarized. The significance of time is evaluated around a shaft in a high level nuclear waste repository. According to the investigation it is generally held that creep and cyclic fatigue are the most important phenomena. They arise from subcritical crack growth which is most affected by stress intensity, chemical environment, temperature, and microstructure. There are many theoretical models, which can be used to analyse creep and cyclic fatigue, but they are defective in describing the triaxial stress condition and strength criteria. Additionally, the required parameters are often too difficult to determine with adequate accuracy. The joint creep rate depends on the affecting stress regime, on the water conditions, and on the properties of filling material. The acoustic emission method is suited to observe long-term microcrack development in field conditions. The computer program developed by Atomic Energy of Canada Limited (AECL) is used to evaluate the time-dependent de-formation around a main shaft. According to the model the enlargement of the shaft radius by 30 cm takes millions of years. The possible reduction of shaft radius by 3 mm will happen during 200 years. The model is very sensitive to changes in stress state, in the uniaxial compressive strength, and in the stress corrosion index

  13. An in-situ stimulation experiment in crystalline rock - assessment of induced seismicity levels during stimulation and related hazard for nearby infrastructure

    Gischig, Valentin; Broccardo, Marco; Amann, Florian; Jalali, Mohammadreza; Esposito, Simona; Krietsch, Hannes; Doetsch, Joseph; Madonna, Claudio; Wiemer, Stefan; Loew, Simon; Giardini, Domenico

    2016-04-01

    A decameter in-situ stimulation experiment is currently being performed at the Grimsel Test Site in Switzerland by the Swiss Competence Center for Energy Research - Supply of Electricity (SCCER-SoE). The underground research laboratory lies in crystalline rock at a depth of 480 m, and exhibits well-documented geology that is presenting some analogies with the crystalline basement targeted for the exploitation of deep geothermal energy resources in Switzerland. The goal is to perform a series of stimulation experiments spanning from hydraulic fracturing to controlled fault-slip experiments in an experimental volume approximately 30 m in diameter. The experiments will contribute to a better understanding of hydro-mechanical phenomena and induced seismicity associated with high-pressure fluid injections. Comprehensive monitoring during stimulation will include observation of injection rate and pressure, pressure propagation in the reservoir, permeability enhancement, 3D dislocation along the faults, rock mass deformation near the fault zone, as well as micro-seismicity. The experimental volume is surrounded by other in-situ experiments (at 50 to 500 m distance) and by infrastructure of the local hydropower company (at ~100 m to several kilometres distance). Although it is generally agreed among stakeholders related to the experiments that levels of induced seismicity may be low given the small total injection volumes of less than 1 m3, detailed analysis of the potential impact of the stimulation on other experiments and surrounding infrastructure is essential to ensure operational safety. In this contribution, we present a procedure how induced seismic hazard can be estimated for an experimental situation that is untypical for injection-induced seismicity in terms of injection volumes, injection depths and proximity to affected objects. Both, deterministic and probabilistic methods are employed to estimate that maximum possible and the maximum expected induced

  14. Uranium rich granite and uranium productive granite in south China

    Mingyue, Feng; Debao, He [CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology, Beijing Research Institute of Uranium Geology (China)

    2012-07-15

    The paper briefly introduces the differences between uranium rich granite and uranium productive granite in the 5 provinces of South China, and discusses their main characteristics in 4 aspects, the uranium productive granite is highly developed in fracture, very strong in alteration, often occurred as two-mica granite and regularly developed with intermediate-basic and acid dikes. The above characteristics distinguish the uranium productive granite from the uranium rich granite. (authors)

  15. Uranium rich granite and uranium productive granite in south China

    Feng Mingyue; He Debao

    2012-01-01

    The paper briefly introduces the differences between uranium rich granite and uranium productive granite in the 5 provinces of South China, and discusses their main characteristics in 4 aspects, the uranium productive granite is highly developed in fracture, very strong in alteration, often occurred as two-mica granite and regularly developed with intermediate-basic and acid dikes. The above characteristics distinguish the uranium productive granite from the uranium rich granite. (authors)

  16. Why Is There an Abrupt Transition from Solid Rock to Low Crystallinity Magma in Drilled Magma Bodies?

    Eichelberger, J. C.; Carrigan, C. R.; Sun, Y.; Lavallée, Y.

    2017-12-01

    We report on a preliminary evaluation, from basic principles of heat and mass transfer, on the unexpectedly abrupt transition from cuttings of solid rock to fragments of crystal poor glass during drilling into magma bodies. Our analysis is based on conditions determined and inferred for the 2009 IDDP-1 well in Krafla Caldera, which entered apparently liquidus rhyolite magma at about 900oC at a depth of 2104 m. Simple conduction would predict some 30 m of crystallization and partial crystallization since the latest time the magma could have been intruded, approximately 30 years prior to discovery by drilling. Option 1: The expected crystallization of magma has occurred but interstitial melt remains. The pressure difference between lithostatic load of about 50 MPa on the mush and 20 MPa hydrostatic pressure in the well causes pore melt to flow from the permeable mush into the borehole, where it becomes the source of the quenched melt chips. To be viable, this mechanism must work over the time frame of a day. Option 2: The expected crystallization is occurring, but high Rayleigh number thermal convection in the magma chamber continuously displaces crystallizing roof magma by liquidus magma from the interior of the body. To be viable, this mechanism must result in overturning magma in the chamber on a time scale that is much shorter than that of crystallization. Option 3: Flow-induced crystal migration away from zones of high shear created during drilling into magma may preferentially produce low-crystal-content melt at the boundary of the borehole, which is then sampled.

  17. Simulation of radio nuclide migration in crystalline rock under influence of matrix diffusion and sorption kinetics: Code development and pre-assessment of migration experiment

    Woerman, A.; Xu Shulan

    1996-04-01

    The overall objective of the present study is to illuminate how spatial variability in rock chemistry in combination with spatial variability in matrix diffusion affects the radio nuclide migration along single fractures in crystalline rock. Models for ground water flow and transport of radio nuclides in a single fracture with micro-fissures have been formulated on the basis of generally accepted physical and chemical principles. Limits for the validity of the models are stated. The model equations are solved by combining finite differences and finite element methods in a computer code package. The computational package consists of three parts, namely, a stochastic field generator, a sub-program that solves the flow problem and a sub-program that solves the transport problem in a single fracture with connecting micro-fissures. Migration experiments have been pre-assessed by simulations of breakthrough curves for a constant concentration change at the upstream boundary. Breakthrough curves are sensitive to variations of parameters, such as, fracture aperture, porosity, distribution coefficient and advection velocity. The impact of matrix diffusion and sorption is manifested in terms of a retention of radionuclides causing a prolonged breakthrough. Heterogeneous sorption was characterized with a variable distribution coefficient for which the coefficient of variation CV(K d )=1 and the integral scale of an exponential covariance function is one tenth of the drill core's length. Simulated breakthrough curves for the heterogeneous sorption case have a relative variance of 3% in comparison to that of homogeneous case. An appropriate experimental set up for investigation of the effect of matrix diffusion and sorption on radio nuclide migration experiments would be an aperture less than 1 mm and porosity larger than 0.5%. 36 refs, 19 figs

  18. Uranium distributions in the mineral constituents of granitoid rocks and the associated pegmatites at Wadi Abu Had, north eastern desert, Egypt

    Nossair, L.M.; Moharem, A.F.; Abdel Warith, A.

    2007-01-01

    Wadi Abu Had area is located at the northern part of the Eastern Desert of Egypt. It covers about 55 km2 of the crystalline basement rocks stretching between latitudes 28o 15'- 28o 25' N and longitudes 32o 25' - 32o 35' E. Abu Had younger granites are fertile (uraniferous) granites as they possess U-contents greater than 11 ppm. Their associated pegmatites show higher U-contents than those of granitoid rocks and hosting secondary uranium minerals. Numerous unzoned and zoned pegmatite pockets are associated with the marginal parts of granodiorite and within younger granites. Zoned pegmatites are the most radioactive ones. They are composed of extremely coarse-grained milky quartz core, intermediate zone of mica and wall zone of feldspars. An alteration zone with secondary uranium minerals (uranophane and beta-uranophane) is found at the contact between quartz core and the intermediate zone.

  19. Characteristics of the crystalline basement beneath the Ordos Basin: Constraint from aeromagnetic data

    Zhentao Wang

    2015-05-01

    Full Text Available Aeromagnetic anomaly zonation of the Ordos Basin and adjacent areas was obtained by processing high-precision and large-scale aeromagnetic anomalies with an approach of reduction to the pole upward continuation. Comparative study on aeromagnetic and seismic tomography suggests that aeromagnetic anomalies in this area are influenced by both the magnetic property of the rock and the burial depth of the Precambrian crystalline basement. Basement depth might be the fundamental control factor for aeromagnetic anomalies because the positive and negative anomalies on the reduction to the pole-upward-continuation anomaly maps roughly coincide with the uplifts and depressions of the crystalline basement in the basin. The results, together with the latest understanding of basement faults, SHRIMP U-Pb zircon dating of metamorphic rock and granite, drilling data, detrital zircon ages, and gravity data interpretation, suggest that the Ordos block is not an entirety of Archean.

  20. Artificial weathering of granite

    Silva Hermo, B.

    2008-06-01

    Full Text Available This article summarizes a series of artificial weathering tests run on granite designed to: simulate the action of weathering agents on buildings and identify the underlying mechanisms, determine the salt resistance of different types of rock; evaluate consolidation and water-repellent treatment durability; and confirm hypotheses about the origin of salts such as gypsum that are often found in granite buildings. Salt crystallization tests were also conducted, using sodium chloride, sodium sulphate, calcium sulphate and seawater solutions. One of these tests was conducted in a chamber specifically designed to simulate salt spray weathering and another in an SO2 chamber to ascertain whether granite is subject to sulphation. The test results are analyzed and discussed, along with the shortcomings of each type of trial as a method for simulating the decay observed in monuments. The effect of factors such as wet-dry conditions, type of saline solution and the position of the planes of weakness on the type of decay is also addressed.En este trabajo se hace una síntesis de varios ensayos de alteración artificial realizados con rocas graníticas. Estos ensayos tenían distintos objetivos: reproducir las formas de alteración encontradas en los edificios para llegar a conocer los mecanismos que las generan, determinar la resistencia de las diferentes rocas a la acción de las sales, evaluar la durabilidad de tratamientos de consolidación e hidrofugación y constatar hipótesis acerca del origen de algunas sales, como el yeso, que aparecen frecuentemente en edificios graníticos. En los ensayos de cristalización de sales se utilizaron disoluciones de cloruro de sodio, sulfato de sodio, sulfato de calcio y agua de mar. Uno de estos ensayos se llevó a cabo en una cámara especialmente diseñada para reproducir la alteración por aerosol marino y otro se realizó en una cámara de SO2, con el objeto de comprobar si en rocas graníticas se puede producir

  1. EXPLOITATION OF GRANITE BOULDER

    Ivan Cotman

    1994-12-01

    Full Text Available The processes of forming, petrography, features, properties and exploitation of granite boulders are described. The directional drilling and black powder blasting is the succesful method in exploitation of granite boulders (boulder technology (the paper is published in Croatian.

  2. FEBEX project: full-scale engineered barriers experiment for a deep geological repository for high level radioactive waste in crystalline host rock. Final report

    Alberdi, J.; Barcala, J. M.; Campos, R.; Cuevas, A. M.; Fernandez, E.

    2000-01-01

    FEBEX has the multiple objective of demonstrating the feasibility of manufacturing, handling and constructing the engineered barriers and of developing codes for the thermo-hydro-mechanical and thermo-hydro-geochemical performance assessment of a deep geological repository for high level radioactive wastes. These objectives require integrated theoretical and experimental development work. The experimental work consists of three parts: an in situ test, a mock-up test and a series of laboratory tests. The experiments is based on the Spanish reference concept for crystalline rock, in which the waste capsules are placed horizontally in drifts surround by high density compacted bentonite blocks. In the two large-scale tests, the thermal effects of the wastes were simulated by means of heaters; hydration was natural in the in situ test and controlled in the mock-up test. The large-scale tests, with their monitoring systems, have been in operation for more than two years. the demonstration has been achieved in the in situ test and there are great expectation that numerical models sufficiently validated for the near-field performance assessment will be achieved. (Author)

  3. Geothermal properties of deep crystalline rock formations in the Rhone valley - Preliminary study; Geothermie du cristallin profond de la vallee du Rhone - Etude preliminaire

    Bianchetti, G; Crestin, G [Alpgeo Sarl, Sierre (Switzerland); Kohl, T [Geowatt AG, Zuerich (Switzerland); Graf, G [Bureau de service et d' ingenierie BSI SA, Lausanne (Switzerland)

    2006-07-01

    This report prepared for the Swiss Federal Office of Energy (SFOE) examines the possibility of cogenerating electric power and heat from geothermal energy stored in deep aquifers in the southwestern Swiss Alps. The project AGEPP (Alpine Geothermal Power Production) investigates an alternative to the well known Hot-Dry-Rock systems by looking at the crystalline formations in the alpine Rhone valley. Since centuries, these formations have been utilized for thermal spas. Two locations, Brigerbad and Lavey-les-Bains have been evaluated in the present report by the companies ALPGEO Sarl, GEOWATT AG and BSI SA. Existing boreholes at both locations show ample flow and substantial temperature gradients down to 600 meters, suggesting possible reservoir temperatures above 110 {sup o}C and a low mineralization (below 5 grams per liter). Flow rates of 50 to 75 liters/s at 110 {sup o}C seem possible and could be utilized in an ORC (Organic Rankine Cycle) for power production up to 1.3 MW. The power production costs are estimated at 0.08 CHF/kWh (singlet system) and 0.27 CHF/kWh (doublet system) respectively. The study implies that cogenerated heat is sold at a price of 0.08 CHF/kWh. These prices could compete with other alternative energies. Phase 2 of the project will evaluate the feasibility at the location of Lavey-les-Bains.

  4. FEBEX project: full-scale engineered barriers experiment for a deep geological repository for high level radioactive waste in crystalline host rock

    Alberid, J; Barcala, J M; Campos, R; Cuevas, A M; Fernandez, E [Ciemat. Madrid (Spain)

    2000-07-01

    FEBEX has the multiple objective of demonstrating the feasibility of manufacturing, handling and constructing the engineered barriers and of developing codes for the thermo-hydro-mechanical and thermo-hydro-geochemical performance assessment of a deep geological repository for high level radioactive wastes. These objectives require integrated theoretical and experimental development work. The experimental work consists of three parts: an in situ test, a mock-up test and a series of laboratory tests. The experiments is based on the Spanish reference concept for crystalline rock, in which the waste capsules are placed horizontally in drifts surround by high density compacted bentonite blocks. In the two large-scale tests, the thermal effects of the wastes were simulated by means of heaters; hydration was natural in the in situ test and controlled in the mock-up test. The large-scale tests, with their monitoring systems, have been in operation for more than two years. the demonstration has been achieved in the in situ test and there are great expectation that numerical models sufficiently validated for the near-field performance assessment will be achieved. (Author)

  5. Portuguese granites associated with Sn-W and Au mineralizations

    Ana M.R. Neiva

    2002-01-01

    Full Text Available In northern and central Portugal, there are different tin-bearing granites. Most of them are of S-type, others have mixed characteristics of I-type and S-type granites and a few are of I-type. Tin-tungsten deposits are commonly associated with Hercynian tin-bearing S-type granites. Some quartz veins with wolframite are associated with an I-type granite, which has a low Sn content. In suites of tin-bearing S-type granitic rocks, Sn content increases as a function of the degree of fractional crystallization. Greisenizations of two-mica S-type granites associated with tin-tungsten mineralizations are accompanied by an increase in SiO2, H2O+, Sn, W, Nb, Ta, Rb, Zn, and Pb and decrease in MgO, Na2O, V, Sc,Zr, and Sr. The granite associated with the Jales gold deposit is of S-type and strongly differentiated like the tin-bearing S-type granites, but it has a very low Sn content. During fractional crystallization, Si, Rb, Sn, Pb, Au, As, Sb, and S increase. During increasing degree of hydrothermal alteration of this granite at the gold-quartz vein walls, there are progressive increases in K2O, H2O+, Sn, Cs, Cu, Pb, Au, Sb, As, and S.

  6. Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 3. Stratigraphies of salt, granite, shale, and basalt

    1978-04-01

    This study presents the methodology and basic literature used to develop generic stratigraphic sections for the various geologic repository host rocks under considerations: salt, granite, shale and basalt

  7. Preliminary environmental assessments of disposal of rock mined during excavation of a federal repository for radioactive waste

    1977-09-01

    Since the environmental impact of mined rock handling will be dependent not only upon the nature of the material and the way in which it might be disposed but also upon the features of the disposal site area and surroundings, it was necessary to select ''reference environmental locii'' within the regions of geological interest to typify the environmental setting into which the rock would be placed. Reference locii (locations) were developed for consideration of the environmental implications of mined rock from: bedded rock salt from the Salina region, bedded rock salt from the Permian region, dome rock salt from the Gulf Interior region, Pierre shale from the Argillaceous region, granite from the crystalline rock region, volcanic basalt rock from the crystalline ash region, and carbonate rock from the limestone region. Each of these reference locii was examined with respect to those demographic, geographic, physical and ecological attributes which might be impacted by various mined rock disposal alternatives. Alternatives considered included: onsite surface storage, industrial or commercial use, offsite disposal, and environmental blending. Potential impact assessment consists of a qualitative look at the environmental implications of various alternatives for handling the mined rock, given baseline characteristics of an area typified by those represented by the ''reference locus''

  8. Water - rock interaction in different rock environments

    Lamminen, S.

    1995-01-01

    The study assesses the groundwater geochemistry and geological environment of 44 study sites for radioactive waste disposal. Initially, the study sites were divided by rock type into 5 groups: (1) acid - intermediate rocks, (2) mafic - ultramafic rocks, (3) gabbros, amphibolites and gneisses that contain calc-silicate (skarn) rocks, (4) carbonates and (5) sandstones. Separate assessments are made of acid - intermediate plutonic rocks and of a subgroup that comprises migmatites, granite and mica gneiss. These all belong to the group of acid - intermediate rocks. Within the mafic -ultramafic rock group, a subgroup that comprises mafic - ultramafic plutonic rocks, serpentinites, mafic - ultramafic volcanic rocks and volcanic - sedimentary schists is also evaluated separately. Bedrock groundwaters are classified by their concentration of total dissolved solids as fresh, brackish, saline, strongly saline and brine-class groundwaters. (75 refs., 24 figs., 3 tabs.)

  9. Raw data from orientation studies in crystalline rock areas of the southeastern United States. [Maps, tables of field data and analytical data for sections of North and South Carolina and Georgia, previously reported sites of uranium mineralization

    Price, V.

    1976-03-01

    Raw data are presented on orientation studies conducted in crystalline rock areas of the Southeast which were chosen because of published references to uranium mineralization. Preliminary data for four orientation study areas are included. These areas are Lamar County, Georgia; Oconee County, South Carolina; Brush Creek, North Carolina; and North Harper, North Carolina. Sample locality maps, tables of field data, and tables of analytical data are included for each study area. (JGB)

  10. Geochemistry of mylonitic tourmaline-bearing granite- gneiss pluton in the northeast of June mine

    Arezoo Moradi

    2017-07-01

    Full Text Available Introduction Studied mylonitic granite-gneiss body is located in the Northwest of the Azna region in the Lorestan province close to the June dimension stone mine. It is a part of the metamorphic- magmatic complex including granite-gneiss, amphibolite, marble and schist. The crystalline basement is attributed to late-Neoproterozoic and it indicates a Panafrican basement, which yields a laser-ablation ICP–MS U–Pb zircon ages of 608 ± 18 Ma and 588 ± 41 Ma (Shakerardakani et al., 2015. There are two granite-gneiss plutons in the complex that are Galeh– Dezh (Shabanian et al., 2009, and June plutons. The Galeh-Doz pluton are previously proposed as syn-deformation pluton with a major S-shaped bend which has been imparted during dextral shearing with a Late Cretaceous (Mohajjel and Fergusson, 2000. However, new age dating on the pluton using U–Pb in the magmatic zircon produced the late-Neoproterozoic dates (Nutman et al., 2014; Shakerardakani et al., 2015. The granite-gneiss plutons show mylonitic fabrics and microstructures (Shabanian et al., 2010. The geochemical characteristics of mylonitic granite-gneiss body near June mine in NW Azna, is in the focus of our research. Materials and methods Petrographic investigations of 30 thin sections were made. Then eight samples were selected and analyzed for whole rock major, trace and REE compositions by ICP-emission spectrometry and ICP-mass spectrometry using natural rock standards as reference samples for calibration at the ACME Analytical Laboratories in Vancouver, British Columbia, Canada. Results The studied gneiss- granitic body has lepido-granoblastic texture as its major texture. It variably shows evidence of dynamic deformation from ultramylonite to protomylonite. The gneiss- granite consists of quartz, alkali feldspar (mostly as perthite, plagioclase, biotite, white mica (muscovite and phengitic muscovite. Accessory phases in the granitoid include, tourmaline, zircon, magmatic epidote

  11. Sensitivity analysis of a coupled hydro-mechanical paleo-climate model of density-dependent groundwater flow in discretely fractured crystalline rock

    Normani, S.D.; Sykes, J.F.

    2011-01-01

    A high resolution three-dimensional sub-regional scale (104 km 2 ) density-dependent, discretely fractured groundwater flow model with hydro-mechanical coupling and pseudo-permafrost was developed from a larger 5734 km 2 regional-scale groundwater flow model of a Canadian Shield setting. The objective of the work is to determine the sensitivity of modelled groundwater system evolution to the hydro-mechanical parameters. The discrete fracture dual continuum numerical model FRAC3DVS-OPG was used for all simulations. A discrete fracture network model delineated from surface features was superimposed onto an approximate 790 000 element domain mesh with approximately 850 000 nodes. Orthogonal fracture faces (between adjacent finite element grid blocks) were used to best represent the irregular discrete fracture zone network. Interconnectivity of the permeable fracture zones is an important pathway for the possible migration and subsequent reduction in groundwater and contaminant residence times. The crystalline rock matrix between these structural discontinuities was assigned mechanical and flow properties characteristic of those reported for the Canadian Shield. The variation of total dissolved solids with depth was assigned using literature data for the Canadian Shield. Performance measures for the sensitivity analysis include equivalent freshwater heads, environmental heads, linear velocities, and depth of penetration by conservative non-decaying tracers released at the surface. A 121 000 year North American continental scale paleo-climate simulation was applied to the domain with ice-sheet histories estimated by the University of Toronto Glacial Systems Model (UofT GSM). Hydro-mechanical coupling between the rock matrix and the pore fluid, due to the ice sheet normal stress, was included in the simulations. The flow model included the influence of vertical strain and assumed that areal loads were homogeneous. Permafrost depth was applied as a permeability reduction

  12. Granitoid magmatism of Alarmaut granite-metamorphic dome, West Chukotka, NE Russia

    Luchitskaya, M. V.; Sokolov, S. D.; Bondarenko, G. E.; Katkov, S. M.

    2009-04-01

    Main tectonic elements of West Chukotka are Alazey-Oloy, South-Anyui and Anyui-Chukotka fold systems, formed as a result of collision between structures of North-Asian continent active margin and Chukotka microcontinent [1-3]. South-Anyui fold system, separating Alazey-Oloy and Anyui-Chukotka systems, is considered as suture zon, formed as a result of oceanic basin closing [4-6]. Continent-microcontinent collision resulted in formation of large orogen with of northern and southern vergent structures, complicated by strike-slip deformations [7, 8]. Within Anyui-Chukotka fold system several rises, where most ancient deposits (crystalline basement and Paleozoic cover of Chukotka microcontinent) are exposed, were distinguished [2, 9-11]. Later they were considered as granite-metamorphic domes [12-14]. Alarmaut dome is located at West Chukotka to the north from Bilibino city and is traced from south to north in more than 120 km. General direction of structure is discordant to prevailing NW extensions of tectonic elements of the region. Paleozoic-Triassic deposits are exposed within the Alarmaut dome: 1) D3-C1 - crystalline schists, quartz-feldspar metasandstones, quartzites, marbles (700 m) [11]; 2) C1 - marblized limestones, quartz-feldspar metasandstones, quartzites, amphibole-pyroxene crystalline schists. Limestones contain corals, indicating Visean age of deposits [11]. Metamorphism reaches amphibolite facies, maximum P-T conditions are 660°С and 5 kbar. Migmatites, indicating in situ partial melting, are observed. Intensity of deformations of Paleozoic rocks increases at the boundary with Triassic deposits [11]; in the western part of dome slices of Pz rocks are separated by blastomylonite horizons [14]. Within Alramaut dome granitoids of Lupveem batholith (central part of dome), Bystrinsky pluton (southeastern part), and small Koyvel' and Kelil'vun plutons were studied. New U-Pb SHRIMP zircon data indicate Early Cretaceous (117-112 m.a.) age of granitoids [15

  13. Fluid geochemistry associated associated to rocks: preliminary tests om minerals of granite rocks potentially hostess of radioactive waste repository; Geoquimica de fluidos associados a rochas: testes preliminares em minerais de rochas granitoides potencialmente hospedeiras de repositorios de rejeitos radioativos

    Amorim, Lucas E.D.; Rios, Francisco J.; Oliveira, Lucilia A.R. de; Alves, James V.; Fuzikawa, Kazuo; Garcia, Luiz; Ribeiro, Yuri, E-mail: LDAmorim@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Matos, Evandro C. de [Industrias Nucleares do Brasil S.A. (INB), Caetite, BA (Brazil)

    2009-07-01

    Fluid inclusions (FI) are micro cavities present on crystals and imprison the mineralizer fluids, and are formed during or posterior to the mineral formation. Those kind of studies are very important for orientation of the engineer barrier projects for this purpose, in order to avoid that the solutions present in the mineral FI can affect the repository walls. This work proposes the development of FI micro compositional studies in the the hostess minerals viewing the contribution for a better understanding of the solution composition present in the metamorphosis granitoid rocks. So, micro thermometric, microchemical and characterization of the material confined in the FI, and the hostess minerals. Great part of the found FI are present in the quartz and plagioclase crystals. The obtained data on the mineral compositions and their inclusions will allow to formulate hypothesis on the process which could occurs at the repository walls, decurrens from of the corrosive character (or not) of the fluids present in the FI, and propose measurements to avoid them

  14. Use of borehole-geophysical logs and hydrologic tests to characterize crystalline rock for nuclear-waste storage, Whiteshell Nuclear Research Establishment, Manitoba, and Chalk River Nuclear Laboratory, Ontario, Canada

    Davison, C.C.

    1982-12-01

    A number of borehole methods were used in the investigation of crystalline rocks at Whiteshell Nuclear Research Establishment and Chalk River Nuclear Laboratory in Canada. The selection of a crystalline-rock mass for the storage of nuclear waste likely will require the drilling and testing of a number of deep investigative boreholes in the rock mass. Although coring of at least one hole in each new area is essential, methods for making in-situ geophysical and hydrologic measurements can substitute for widespread coring and result in significant savings in time and money. Borehole-geophysical logging techniques permit the lateral extrapolation of data from a core hole. Log response is related to rock type, alteration, and the location and character of fractures. The geophysical logs that particularly are useful for these purposes are the acoustic televiewer and acoustic waveform, neutron and gamma, resistivity, temperature, and caliper. The acoustic-televiewer log of the borehole wall can provide high resolution data on the orientation and apparent width of fractures. In situ hydraulic tests of single fractures or fracture zones isolated by packers provide quantitative information on permeability, extent, and interconnection. The computer analysis of digitized acoustic waveforms has identified a part of the waveform that has amplitude variations related to permeabilities measured in the boreholes by packer tests. 38 refs., 37 figs., 4 tabs

  15. Contribution to uranium geochemistry in intrusive granites; Contribution a la geochimie de l'uranium dans les granites intrusifs

    Coulomb, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-01-15

    This work aims to define the position of a certain number of French granitic deposits within the field of the geochemistry of granites in general, and of the geochemistry of uranium in particular. The regions concerned are: - 3 French Hercynian ranges, in the Vendee, in Brittany and in the Morvan, - 1 African range, probably precambrian, of the Hoggar. For each range, the petrochemical framework is first of all determined and then the degree of chemical homogeneity of the rocks is evaluated. In the petrochemical groups thus obtained the geochemical behaviour of the uranium is studied. From a point of view of the geochemistry of the granites under investigation, a comparison of the laws of distribution of the major elements in the 4 ranges shows up a convergence of average composition which was not anticipated by geological and petrographic considerations alone. The statistical and geochemical distribution laws of the total uranium as a function of the petrochemical variations are established. A study of the chemical forms of uranium in the rocks has drawn an attention to the qualitative and quantitative importance of the fraction of this uranium soluble in dilute acids. We have therefore reconsidered on the one hand, the laws of distribution of the insoluble uranium, which represents essentially the uranium fixed in crystalline structures (zircon, allanite...), and we have justified on the other hand the interest presented by the soluble uranium: this, although more complex in character, presents a geochemical unity in post magmatic phenomena which makes possible to find a genetic connection between the uraniferous deposits and the intrusive massifs. Finally we have given a plan of the geochemical cycle of uranium, in which we hope to have provided some more accurate data on the igneous phase. (author) [French] Le but du travail presente est de situer sur le plan de la geochimie des granites en general, sur le plan de la geochimie de l'uranium en particulier, un

  16. Contribution to uranium geochemistry in intrusive granites; Contribution a la geochimie de l'uranium dans les granites intrusifs

    Coulomb, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-01-15

    This work aims to define the position of a certain number of French granitic deposits within the field of the geochemistry of granites in general, and of the geochemistry of uranium in particular. The regions concerned are: - 3 French Hercynian ranges, in the Vendee, in Brittany and in the Morvan, - 1 African range, probably precambrian, of the Hoggar. For each range, the petrochemical framework is first of all determined and then the degree of chemical homogeneity of the rocks is evaluated. In the petrochemical groups thus obtained the geochemical behaviour of the uranium is studied. From a point of view of the geochemistry of the granites under investigation, a comparison of the laws of distribution of the major elements in the 4 ranges shows up a convergence of average composition which was not anticipated by geological and petrographic considerations alone. The statistical and geochemical distribution laws of the total uranium as a function of the petrochemical variations are established. A study of the chemical forms of uranium in the rocks has drawn an attention to the qualitative and quantitative importance of the fraction of this uranium soluble in dilute acids. We have therefore reconsidered on the one hand, the laws of distribution of the insoluble uranium, which represents essentially the uranium fixed in crystalline structures (zircon, allanite...), and we have justified on the other hand the interest presented by the soluble uranium: this, although more complex in character, presents a geochemical unity in post magmatic phenomena which makes possible to find a genetic connection between the uraniferous deposits and the intrusive massifs. Finally we have given a plan of the geochemical cycle of uranium, in which we hope to have provided some more accurate data on the igneous phase. (author) [French] Le but du travail presente est de situer sur le plan de la geochimie des granites en general, sur le plan de la geochimie de l'uranium en particulier

  17. The Serra do Carambei Granite - PR and the uraniferous anomalism

    Pinto-Coelho, C.V.

    1986-01-01

    The Serra do Carambei Granite forms a pluton relatively homogeneous, covering about 33 km 2 , cropping out as an elongate retangular body trending NE-SW, being emplaced in the Cunhaporanga Granitoid Complex. Its characteristics indicates a kind of hololeucocratic granite, equigranular, medium to coarse-grained, consisting predominantly of microperthitic alkali-feldspar, quartz and a small amount of biotite (less than 1%), thus being classified as an alaskite. Chemical data allows a classification in the group of granite with high contents of silica (74-76% Wt. SiO 2 ), dominantly alkaline chemism and hypersolvus character, derived from a parental magma under saturated in water with distinguished features of granitoids from the magnetite series and types I and A granites. The pluton shows important chemical variations due to weathering processes. However detailed chemical studies reveal the presence of anomalous concentrations of trace elements such as U, Sn, Nb, Y, Zr, the Serra do Carambei Granite lacks economically important mineralizations because of the absence of well-developed tardi/pos-magmatic processes that could concentrate them. The SW side of the granite is cut by leucocratic rhyolite dykes that show some radiometric anomalies. These rocks, which are highly diferentiated, were emplaced contemporaneously to the Serra do Carambei Granite. Although petrographic and chronological similarities are found between the uraniferous alaskite of Roessing (Namibia) and the Serra do Carambei Granite anyhow it was not possible to establish any lateral continuity with the uranifeous Pan-African Province. (Author) [pt

  18. PRINCIPLE ROCK TYPES FOR RADIOACTIVE WASTE REPOSITORIES

    Sibila Borojević Šostarić

    2012-07-01

    Full Text Available Underground geological storage of high- and intermediate/low radioactive waste is aimed to represent a barrier between the surface environment and potentially hazardous radioactive elements. Permeability, behavior against external stresses, chemical reacatibility and absorption are the key geological parameters for the geological storage of radioactive waste. Three principal rock types were discussed and applied to the Dinarides: (1 evaporites in general, (2 shale, and (3 crystalline basement rocks. (1 Within the Dinarides, evaporite formations are located within the central part of a Carbonate platform and are inappropriate for storage. Offshore evaporites are located within diapiric structures of the central and southern part of the Adriatic Sea and are covered by thick Mesozoic to Cenozoic clastic sediment. Under very specific circumstances they can be considered as potential site locations for further investigation for the storage of low/intermediate level radioactive wast e. (2 Thick flysch type formation of shale to phyllite rocks are exposed at the basement units of the Petrova and Trgovska gora regions whereas (3 crystalline magmatic to metamorphic basement is exposed at the Moslavačka Gora and Slavonian Mts. regions. For high-level radioactive waste, basement phyllites and granites may represent the only realistic potential option in the NW Dinarides.

  19. Experimental study of the transport of HTO, {sup 3}6Cl and {sup 1}37Cs through barriers of bentonite and granite; Estudio experimental del transporte de HTO, {sup 3}6Cl y {sup 1}37Cs a traves de barreras de bentonita y granito

    Mingarro, M.; Garcia-Gutierrez, M.; Morejon, J.; Missana, T.; Gil, P.

    2013-07-01

    The evaluation of the behavior of the engineered (bentonite) and natural (granite) barrier of a deep geological repository of high level radioactive waste, needs the knowledge of radionuclide migration and retention processes under conditions as similar as possible to the real ones. In CIEMAT a large-scale experiment has been designed with the objective of studying diffusive transport at the bentonite/granite interface of a geological repository in crystalline rock. The diffusion of three tracers has been analyzed: HTO (as conservative and neural element); Cl (as conservative anionic element) and Cs (as conservative cationic element). It was observed that cesium disappeared very fast from the water deposit, due to its strong retention on bentonite. On the other hand, HTO and Cl, disappeared much slower and could be finally detected in the granite at several centimeters from the original source.

  20. Crystalline and Crystalline International Disposal Activities

    Viswanathan, Hari S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffrey De' Haven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, Nataliia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-06

    This report presents the results of work conducted between September 2015 and July 2016 at Los Alamos National Laboratory in the crystalline disposal and crystalline international disposal work packages of the Used Fuel Disposition Campaign (UFDC) for DOE-NE’s Fuel Cycle Research and Development program. Los Alamos focused on two main activities during this period: Discrete fracture network (DFN) modeling to describe flow and radionuclide transport in complex fracture networks that are typical of crystalline rock environments, and a comprehensive interpretation of three different colloid-facilitated radionuclide transport experiments conducted in a fractured granodiorite at the Grimsel Test Site in Switzerland between 2002 and 2013. Chapter 1 presents the results of the DFN work and is divided into three main sections: (1) we show results of our recent study on the correlation between fracture size and fracture transmissivity (2) we present an analysis and visualization prototype using the concept of a flow topology graph for characterization of discrete fracture networks, and (3) we describe the Crystalline International work in support of the Swedish Task Force. Chapter 2 presents interpretation of the colloidfacilitated radionuclide transport experiments in the crystalline rock at the Grimsel Test Site.

  1. Isotopic geochronology of the Western Carpathian crystalline complex: the present state

    Cambel, B.; Kral, J.

    1989-01-01

    Main events in the Western Carpathian crystalline complex documented by the U-Th-Pb, Rb-Sr, K-Ar and FT methods are as follows: Regional metamorphism of sedimentary rocks from the Tatric unit documented by isotopic homogenization of the 87 Sr/ 86 Sr ratio took place 400 million years ago (Silurian-Devonian boundary). Subsequent metamorphism of these rocks is associated with intrusions of granitoid bodies. The age of rhyolite volcanism of Gelnica sequence in the Gemericum is identical with that of the first stage of regional metamorphism. Granitoid plutonism covers a long time interval ranging from 390 to 280 million years. The presence of late Alpine granites has not yet been proved. Cooling of rocks from the crystalline complex to a temperature of ca. 270 degC was attained in the Tatric rocks ca. 300 million years ago and in the Veporic (Gemeric) rocks ca. 90-120 million years ago. The latest post-orogenic uplift differs in the Tatricum (most often Miocene) and the Veporicum (Upper Cretaceous). (author). 8 fis., 1 tab., 51 refs

  2. Paleohydrogeological events recorded by stable isotopes, fluid inclusions and trace elements in fracture minerals in crystalline rock, Simpevarp area, SE Sweden

    Drake, Henrik; Tullborg, Eva-Lena

    2009-01-01

    Fracture minerals calcite, pyrite, gypsum, barite and quartz, formed during several events have been analysed for δ 13 C, δ 18 O, δ 34 S, 87 Sr/ 86 Sr, trace element chemistry and fluid inclusions in order to gain knowledge of the paleohydrogeological evolution of the Simpevarp area, south-eastern Sweden. This area is dominated by Proterozoic crystalline rocks and is currently being investigated by the Swedish Nuclear Fuel and Waste Management Co. (SKB) in order to find a suitable location for a deep-seated repository for spent nuclear fuel. Knowledge of the paleohydrogeological evolution is essential to understand the stability or evolution of the groundwater system over a time scale relevant to the performance assessment for a spent nuclear fuel repository. The ages of the minerals analysed range from the Proterozoic to possibly the Quaternary. The Proterozoic calcite and pyrite show inorganic and hydrothermal-magmatic stable isotope signatures and were probably formed during a long time period as indicated by the large span in temperatures (c. 200-360 deg. C) and salinities (0-24 wt.% eq. CaCl 2 ), obtained from fluid inclusion analyses. The Paleozoic minerals were formed from organically influenced brine-type fluids at temperatures of 80-145 deg. C. The isotopic results indicate that low temperature calcite and pyrite may have formed during different events ranging in time possibly from the end of the Paleozoic until the Quaternary. Formation conditions ranging from fresh to brackish and saline waters have been distinguished based on calcite crystal morphologies. The combination of δ 18 O and crystal morphologies show that the fresh-saline water interface has changed considerably over time, and water similar to the present meteoric water and brackish seawater at the site, have most probably earlier been residing in the bedrock. Organic influence and closed system in situ microbial activity causing disequilibrium are indicated by extremely low δ 13 C (down

  3. Permian ultrafelsic A-type granite from Besar Islands group, Johor, peninsular Malaysia

    Ghani, Azman A.; Hazad, Fatin Izzani; Jamil, Azmiah; Xiang, Quek Long; Atiqah Wan Ismail, Wan Nur; Chung, Sun-Lin; Lai, Yu-Ming; Roselee, Muhammad Hatta; Islami, Nur; Nyein, Kyaw Kyaw; Amir Hassan, Meor Hakif; Abu Bakar, Mohd Farid; Umor, Mohd Rozi

    2014-12-01

    The granitic rocks of the peninsula have traditionally been divided into two provinces, i.e., Western and Eastern provinces, corresponding to S- and I-type granite respectively. The Western Province granite is characterised by megacrystic and coarse-grained biotite, tin-mineralised, continental collision granite, whereas, the Eastern Province granite