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No description available.

Development of a scientific basis for management of uranium bearing wastes and contaminants requires information from natural geologic systems. The following study of the Coles Hill uranium deposit and associated weathered zone constrains processes leading to the natural attenuation of uranium within an oxidizing, fluid rich environment typical of the eastern US. At the Coles Hill deposit fracture hosted, primary U(IV) bearing mineral assemblages formed during hydrothermal activity associated with Mesozoic faulting. The most abundant ore assemblage consists of coffinite and apatite, but uraninite-zeolite and uraninite-calcite assemblages are also present. Within the shallow bedrock there is a uranium redox transition where alteration of U(IV) minerals has produced secondary uranium minerals. Geochemical data suggests that the volume of rock containing this U(IV)/U(VI) transition is acting as a closed system with respect to uranium mass transport during oxidation. The dominant mechanism of uranium fixation within the oxidizing zone is the precipitation of Ba-U(VI) phosphates (meta-autunite group). Speciation and mineral stability calculations indicate that ground waters from the Coles Hill weathered zone are saturated with respect to Ba-meta-autunite and that this mineral is capable of buffering dissolved uranium concentrations to values lower than 20 parts per billion. U(VI) phosphates of the meta-autunite group are not stable in the vadose zone (soil pH ~ 4.5) at the Coles Hill site. In this zone uranium is associated with (Ba, Ca, Sr) aluminum phosphate of the crandallite group as well as with phosphate sorbed to iron oxy-hydroxide mineral coatings. Uranium leached from the vadose zone is reprecipitated as new meta-autunite minerals below the water table due to higher pH conditions of ~6.0 and relatively high activity ratios of dissolved phosphate to carbonate (e.g. log [H2PO4-/HCO3-] > -3). It is estimated that the U(VI) phosphates responsible for the natural attenuation of uranium at this site persist within the weathering zone for hundreds of thousands of years. Thus, the Coles Hill deposit represents an excellent natural laboratory for the study of uranium attenuation with potential applications for the design and implementation of cost effective remediation and containment strategies, such as soil amendments techniques and in-situ reactive barriers technologies. / Ph. D.

The Coles Hill uranium deposit in Pittsylvania County, Virginia represents the largest unmined uranium resource in the United States, with an estimated resource of 110 million pounds of U3O8 in place with a cutoff grade of 0.025 wt% U3O8. The deposit is localized along a geologic unit that parallels the Chatham Fault, which separates the Triassic Danville Basin to the east from the older crystalline rocks to the west. The location of the Chatham Fault is important to understanding distribution of ore and for developing an effective mine plan. In this study the Chatham Fault location has been inferred from ground conductivity and ground penetrating radar (GPR) surveys. Anomalies in the data are consistent with previously mapped fault locations based on drillhole and geophysical data, such as gravity and magnetic surveys, collected in the 1980s. These results confirm that the strike of the Chatham Fault is approximately N40ºE and dips to the southeast with dip values ranging from 70º, in the northeast, to 50º, in the southwest. / Master of Science

During periods of reduced precipitation, flow in low-order, upland streams may be reduced and may stop completely. Under these "low flow" conditions, fecal bacteria directly deposited in the stream dominate in-stream bacteria loads. When developing a Total Maximum Daily Load (TMDL) to address a bacterial impairment in an upland, rural watershed, direct deposit (DD) fecal bacteria sources (livestock and wildlife defecating directly in the stream) often drive the source-load reductions required to meet water quality criteria. Due to limitations in the application of existing watershed-scale water quality models, under low-flow conditions the models can predict unrealistically high in-stream fecal bacteria concentrations. These unrealistically high simulated concentrations result in TMDL bacteria source reductions that are much more severe than what actually may be needed to meet applicable water quality criteria. This study used the Hydrological Simulation Program-FORTRAN (HSPF) to compare three low-flow DD simulation approaches and combinations (treatments) on two Virginia watersheds where bacterial impairment TMDLs had been previously developed and where low-flow conditions had been encountered. The three methods; Flow Stagnation (FS), DD Stage Cut-off (SC), and Stream Reach Surface Area (SA), have all been used previously to develop TMDLs. A modified version of the Climate Generation (CLIGEN) program was used to stochastically generate climate inputs for multiple model simulations. Violations of Virginia's interim fecal coliform criteria and the maximum simulated in-stream fecal coliform concentration were used to compare each treatment using ANOVA and Kruskal Wallis rank sum procedures. Livestock DD bacteria sources were incrementally reduced (100%, 50%, 15%, 10%, 5%) to represent TMDL load reduction allocation scenarios (allocation levels). Results from the first watershed indicate that the FS method simulated significantly lower instantaneous criterion violation rates at all allocation levels than the Control. The SC method reduced the livestock DD load compared to the Control, but produced significantly lower instantaneous criterion violation rates only at the 100% allocation level. The SA method did not produce significantly different instantaneous criterion violation rates compared to the Control. Geometric mean criterion violation rates were not significantly different from the Control at any allocation level. The distributions of maximum in-stream fecal coliform concentrations simulated by the combinations SC + FS and SC + SA + FS were both significantly different from the Control at the 100% allocation level. The second watershed did not produce low-flow conditions sufficient to engage the FS or SC methods. However, the SA method produced significantly different instantaneous violation rates than the Control at all allocation levels, which suggests that the SA method continues to affect livestock DD loads when low-flow conditions are not simulated in the watershed. No significant differences were found in the geometric mean violation rate or distribution of maximum simulated in-stream fecal coliform concentrations compared to the Control at any allocation level. This research suggests that a combination of the SC and FS methods may be the most appropriate treatment for addressing unrealistically high concentrations simulated during low-flow conditions. However, this combination must be used with caution as the FS method may increase the maximum simulated in-stream fecal coliform concentration if HSPF simulates zero volume within the reach. / Master of Science

The Coles Hill uranium deposit in Pittsylvania County, VA, is the largest un-mined uranium deposit in the United States. The deposit is located in the Virginia Piedmont in a geologic unit located immediately west of the Chatham Fault, which separates the granitic rocks of the Virginia Piedmont to the west from the metasediments of the Danville Triassic basin to the east. Groundwater at the site flows through a complex interconnected network of fractures controlled by the geology and structural history of the site. In this study groundwater is characterized in a small study area just south of the main deposit. Methods used in this investigation include electrical resistivity profiling, bore hole logging, a pumping test, and age dating and water chemistry. In this thesis groundwater flow is confirmed to occur from the Piedmont crystalline rocks across the Chatham Fault and into the Triassic basin at the study area as evidenced by pumping test data and static water-level data from observation wells. Well logs have identified fractures capable of transmitting water in the granitic rocks of the Piedmont, the Triassic basin metasediments and the Chatham Fault but the largest quantities of flow appear to occur in the Triassic basin. A definable recharge area for the groundwater present at Coles Hill can not yet be determined due to the complexity of the fracture system, but age dating confirms that groundwater is composed of both young and old (>60 years) components, indicating that at least a portion of groundwater at Coles Hill originates from a more distant area. / Master of Science

Магистерская диссертация посвящена вопросам формирования депозитной политики коммерческих банков и управления депозитным портфелем. Целью исследования является разработка и экономическое обоснование эконометрической модели, позволяющей оптимизировать состав депозитных ресурсов банка. В работе сделан вывод о том, что повышение качества управления депозитными ресурсами банка способствует повышению конкурентоспособности банка в условиях высокой конкуренции и нормативных требований Банка России. / Master thesis is devoted to formation of deposit policy of banks and management of deposit portfolio. Aim of the study is the development and economic justification of the econometric model that allows optimizing the composition of deposit resources of a bank. The work concluded that improving the quality of managing deposit resources of a bank contributes to improving competitiveness of bank in conditions of high competition and regulatory requirements of the Bank of Russia.

Uniaxial consolidation experiments on Mass Transport Deposit (MTD) and non-MTD core samples from Ursa Basin, Gulf of Mexico, show MTDs have a lower porosity at a given effective stress compared to adjacent non-MTD sediments; a behavior observed in additional experiments on lab remolded Ursa core and resedimented Boston Blue Clay (BBC). I hypothesize debris flow action remolded the sediment: removing its stress history through shearing action, resulting in dense sediments at shallow depth. I supplement testing this hypothesis through lab remolding of BBC (in addition to Ursa clay) due to the greater availability and knowledge of this material. Ursa MTDs record multiple submarine slope failure events within the upper 200 meters below sea floor (mbsf); the most prominent is labeled MTD-2. MTDs have lower porosity and higher bulk density than surrounding, non-MTD, sediment. Porosity ([phi]) is 52% at 125mbsf – immediately below MTD-2; whereas [phi] is 46% at 115mbsf – within MTD-2. Comparison of non-MTD samples to MTD-2 samples, and intact to remolded samples, shows a decrease in sediment compressibility (Cc) within the MTD-2 and remolded sediments. Permeability within Ursa mudstones also declines with porosity according to: log (k) = A[phi] - B. Permeability is slightly higher within MTD-2; however grain size analysis indicates lower clay content in MTD-2 versus the non-MTDs. Pre-consolidation stress interpretations from the experiments show a linear trend in both MTD and non-MTD sediments, indicating both geologic units depict the same pore pressure profile. Remolding via debris flow explains the origin of MTDs at Ursa and governs the evolution of this geologic unit to its dense, highly consolidated, state today. At some point, slope failure triggered movement of the sediment down slope in form of a debris flow. The shearing action of the debris flow weakened the sediment, reducing its ability to support the overburden. As consolidation resumed, the remolded sediment followed a new, less steep, Cc curve. Within the geologic record, a distinctive dense, shallow unit is preserved; evidence for historical slope failure. / text

In the northern part of Swedish Caledonides, north of Lake Torneträsk is a 7 km long exposure of a breccia layer. The layer thins westwards and eastwards from the central part where it is up to 27 m thick. It is called the Vakkejokk Breccia after the type section. The breccia has been described in literature since about a century, but its origin is enigmatic. The breccia layer is since the summer of 2012 investigated by three geologists specialized in impact craters, Paleozoic sediments, and the Caledonian orogeny. They put forward evidence for the breccia being formed by a hypervelocity impact during the Lower Cambrian at approximately 520 Ma (Ormö et al. 2017). At that time the target area was a shallow epicontinental sea that surrounded the mainly peneplanized continent Baltica. An impact into the sea is known to generate tsunami waves as well as resurge deposits when the water brings ejected and rip-up material back into the crater. Ormö et al. (2017) suggest the top part of the Vakkejokk Breccia to include such resurge deposits. The depositional marine environment is also known to rapidly protect an impact crater from further erosion. It is possible that only the topographic rim of the Vakkejokk crater was eroded during the millions of years it may have taken before the crater was covered by younger sediments. About 100 m.y. after the formation, it was completely covered by overthrust nappes during the Caledonian orogeny, when Baltica and Laurentia collided. The crater itself is not exposed today, merely parts of what is thought to be the ejecta layer and resurge deposits. This Bachelor of Science project aimed to investigate the putative resurge deposits to learn more about the process of formation and the provenance in the target of the clasts in the deposits. This was carried out by three short drillcores through the resurge deposit part of the Vakkejokk Breccia layer. The place to drill the boreholes was chosen at an outcrop which is proximal to the putative hidden crater. The retrieved drillcores were cut longitudinally, then polished and photographed in high resolution. Each core was then analyzed in an image analysis software with respect to clast granulometry and lithology. To the results are presented as graphs showing clast size, size sorting, clast shape, of the relative amounts of different lithologies and the matrix content. The results are discussed with respect to well-documented analogue marine-target craters

by Lok Kin-wah, Leo, Loke Sik-yin, Peggy. / Bibliography: leaves 70-72 / Thesis (M.B.A.)--Chinese University of Hong Kong, 1983