Reconstruction of Basin and Range extension and westward motion of the Sierra Nevada Block
Robert J. Brady, Brian P. Wernicke, Nathan A. Niemi, 2000. "Reconstruction of Basin and Range extension and westward motion of the Sierra Nevada Block", Great Basin and Sierra Nevada, David R. Lageson, Stephen G. Peters, Mary M. Lahren
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Recent studies, including structural mapping, stratigraphic and sedimentologic studies, geothermochronology, and geodetic measurements, have improved our understanding of the kinematics of Miocene to Recent deformation in the central Basin and Range. Based on reconstructions of rocks in the extensionally dismembered foreland and leading edge of the Sevier thrust belt, offset along the Las Vegas Valley shear zone, and on the provenance of a unique clast assemblage in proximal channel facies deposits at Frenchman Mountain, the southern and northern Lake Mead extensional domains have extended ~94 km and ~46 km, respectively. A compilation of >70 cooling ages from the Gold Butte crystalline block indicates that onset of this extension occurred at ~20 Ma, with rapid, large-magnitude extension beginning at ~15 Ma. In the Death Valley extended domain, studies of the provenance, depositional environment, and age of the Eagle Mountain Formation show that middle Miocene siliciclastic strata occurring in a northwest-trending belt from Chicago Valley to the Cottonwood Mountains were all deposited in an environment proximal to the Hunter Mountain batholith of the Cottonwood Mountains. This requires ~100 km of roughly southeast-northwest extensional and strike-slip displacement since ~11 Ma. Identification of extensionally dismembered Cenozoic structures, correlative with structures in the Cottonwood Mountains, Panamint Range, Bare Mountain, the CP Hills, and the Funeral Mountains, are also consistent with ~100 km of west-northwest extension across the Death Valley region.
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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.