Superposed fold-thrust events at the Nevada Test Site
Patricia H. Cashman, James C. Cole, James H. Trexler, Jr., 2000. "Superposed fold-thrust events at the Nevada Test Site", Great Basin and Sierra Nevada, David R. Lageson, Stephen G. Peters, Mary M. Lahren
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The Nevada Test Site (NTS), in southern Nye County, Nevada, straddles significant pre-Tertiary structural and stratigraphic boundaries. Detailed stratigraphy and biostratigraphy of the Upper Paleozoic section delineates the regional thrust sheets and constrains their burial histories. The Paleozoic rocks record three phases of contractional deformation, overprinted by strike-slip faulting. These occurred in the following order: (1) foreland-vergent folding and imbricate thrusting in the footwall of the Belted Range thrust; (2) hinterland-vergent folding and thrusting; and (3) north-vergent folding that we interpret as footwall deformation below a third major thrust system. Sinistral slip, typically accompanied by minor east-west shortening, has occurred along a series of north-northeast-north-northwest-striking faults around Yucca Flat. This strike-slip faulting postdates both foreland-vergent and hinterland-vergent deformation, and predates the Cretaceous Climax stock; its age relative to the north-vergent folding and thrusting is unknown. Our new understanding of the geometry of these structures provides new insights into the correlation and interpretation of regional structural features. Field trip stops will examine: (1) the stratigraphic dif-ferences that allow us to distinguish the regional thrust sheets and constrain their burial histories; and (2) the field relationships that document the kinematics and relative ages of the penetrative deformational events.
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Great Basin and Sierra Nevada, the second volume of the Geological Society of America Field Guide Series, focuses on the dynamic and spectacular geology of this region, providing the inspiring backdrop for the 2000 GSA Annual Meeting in Reno. This volume gives complete coverage of field trips held in conjunction with that meeting, and contains 20 chapters organized into three sections. The first section consists of 16 chapters arranged in geochronological order, beginning with the active tectonics of Lake Tahoe and the historical surface faulting and paleoseismicity of the central Nevada seismic belt, and ending with the Neoproterozoic glacial record of Death Valley. In between are chapters dealing with Basin and Range extension, Eocene magmatism, Mesozoic plutonism in the Sierra Nevada, Paleozoic subduction, and Ordovician stratigraphy, to name a few. The second section covers the geology of the Nevada Test Site and the nuclear-waste repository at Yucca Mountain. The last section is an invited field guide from the 1999 GSA Cordilleran Section meeting that covers the wines and geology of Napa Valley, California. Overall, Great Basin and Sierra Nevada is a comprehensive compilation of new and exciting research on this amazingly diverse region, with well-crafted guides to field localities of special interest. Full-color plates in some chapters make this guide an especially appealing and useful volume.