Results 1 - 10 of 1116
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[en] The purpose of the Central Plateau Vadose Zone (CPVZ) Geoframework model (GFM) is to provide a reasonable, consistent, and defensible three-dimensional (3D) representation of the vadose zone beneath the Central Plateau at the Hanford Site to support the Composite Analysis (CA) vadose zone contaminant fate and transport models. The GFM is a 3D representation of the subsurface geologic structure. From this 3D geologic model, exported results in the form of point, surface, and/or volumes are used as inputs to populate and assemble the various numerical model architectures, providing a 3D-layered grid that is consistent with the GFM. The objective of this report is to define the process used to produce a hydrostratigraphic model for the vadose zone beneath the Hanford Site Central Plateau and the corresponding CA domain.
[en] The objective of this study was to realize a three-dimensional (3-D) geological model of the deep basin structure of the Middle Durance region (of folds and faults) by integration of geological and geophysical data, and to evaluate its fault geometry and tectonic history. All of the available geophysical and geological data were compiled in three dimensions using the gOcad geo-modeler. The geological and geophysical data were used to build a 3-D geological model of the Middle Durance region. The data on the 3-D geometry of fault surfaces and stratigraphic horizons and the thickness maps of the main stratigraphic units are supported by the 3-D geological model. We show that the Middle Durance Fault cannot be interpreted as a single fault plane that affected the entire Meso-Cenozoic sedimentary layers and the Paleozoic basement but as a listric segmented faulting system in sedimentary layers, rooted in Triassic evaporites and a normal block faulting system in the basement. This decoupling level in the Triassic layers reveals thin-skin deformation, formed by strong mechanical decoupling between the Mesozoic sedimentary cover and the Paleozoic basement. This study also confirms that the Provence geological structure has resulted mainly from Pyrenean deformation, which was partly reactivated by Alpine deformation. We demonstrate that the Middle Durance Fault Zone is a transfer fault that accommodates deformation of the sedimentary filling of the South-East Basin through modified fold geometry over a zone of 7 km to 8 km around the main segment of the fault zone. (authors)
[en] The floristic survey of the Thal desert, Punjab, Pakistan was carried out during 2010 to 2013. So far, 248 species distributed across 166 genera and 38 families were identified during the report period. Besides, one species viz., Themeda triandra was recorded for the first time from Pakistan. Of them, one fern, 4 monocots and 33 dicots families were determined. The most dominating family was Poaceae that contributed 52 species (21.49%), followed by Fabaceae (34 spp., 13.05%) and Amaranthaceae and Asteraceae (17 spp., 7.02% each). The largest genera were Euphorbia (6 spp.), Cyperus, Eragrostis and Solanum (5 spp. each), Mollugo, Heliotropium and Cenchrus (4 spp. each), Acacia, Prosopis, Tephrosia, Corchorus, Boerhavia and Ziziphus (3 spp. each). This checklist consists of updated systematic families and plants names that will provide a useful starting point for further ecological and bioprospective research of the area under study. (author)
[en] The presence of clay deposits in the south-southern part of Nigeria was investigated using the electrical resistively method. The vertical electrical sounding was adopted for the investigation using the Schlumberger electrode arrangement. Resistively soundings were collected from several locations, which were evenly distributed within the study area to explore the clay deposits. Models were generated for computer iterative technique. Borehole data were also collected using spontaneous potential logging method, as well as driller's log in some selected sites within the study area, so as to correlate surface measurements with borehole records. Analysis based on five depth-related resistively contour maps, as well as selected cross-sectional profiles, confirm the existing dual regional geological environment of the area. Finally, it was established quantitatively that there were comparatively larger clay mineral deposits in the sedimentary environment than in the basement complex areas. (author)
[en] The different models for the genesis of U deposits are presented. They are classified in 4 groups (soil alteration, hydrothermal diagenesis, deep magma differentiation and metamorphism). A critical assessment is made for each model. 56 refs
[fr]Les hypotheses de formation des gisements ont ete regroupees en quatre domaines: (alteration pedologique ou superficielle, diagenetique hydrothermale, differenciations magmatiques profondes et metamorphisme). Si certains modeles ont des points communs, d'autres sont totalement opposes. Mais il existe en plus des modeles unitaires, faisant intervenir un ou plusieurs phenomenes de chaque groupe. Nous nous proposons d'exposer chaque modele et d'en faire la critique en discutant les elements qui ne s'integrent pas parfaitement a ce modele
[en] A review was conducted on Chapters 4 and 5 of the SKB SR 97 - Post Closure Safety Main Report, with a background study of Chapters 1-3, as well as a study of the related sections of support documents SKB TR 95-22, SKB TR 99-20 and SKB TR 99-07. Main comments include: (1) Need for Iteration and Integration between Model Conceptualization and Model Investigations; (2) Need for Reviews by Two Types of Experts; (3) Need for Structured Expert Elicitation and Documentation; (4) Need for Careful Definition of Base Scenario; (5) Suggestion of the Use of Zeroth Order Scenario; (6) Confusion in the Definition of 'Variables'; (7) Need to Ensure Inclusion of Tertiary and Higher-Order Coupled Processes; (8) Need to Consider Model Abstraction and Associated Uncertainty; (9) Need for Care in Handling Analyses at Different Levels of Details. Additional comments are made more specifically on the THMC diagrams
[en] Discrete feature network models attempt to recreate water conducting features realistically with respect to geometric and hydraulic properties. Two recently developed methods are overviewed for developing and calibrating discrete feature models. The firs method uses dimensional information from well test data to calibrate discrete feature network models. The second addresses approaches for representing networks of planar features as equivalent one-dimensional conductors. (author)
[en] To develop site characterization technologies for a radioactive waste disposal research in KAERI, the geological and hydrogeological investigations have been carried out since 1997. In 2006, the KURT (KAERI Underground Research Tunnel) was constructed to study a solute migration, a microbiology and an engineered barrier system as well as deeply to understand geological environments in in-situ condition. This study is performed as one of the site characterization works around KURT. Several investigations such as a lineament analysis, a borehole/tunnel survey, a geophyscial survey and logging in borehole, were used to construct the geological model. As a result, the geological model is constructed, which includes the lithological model and geo-structural model in this study. Moreover, from the results of the in-situ hydraulic tests, the hydrogeological properties of elements in geological model were evaluated.