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Book Structural Relationships of Pre Tertiary Rocks in the Nevada Test Site Region Southern Nevada

Download or read book Structural Relationships of Pre Tertiary Rocks in the Nevada Test Site Region Southern Nevada written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the evidence for a revised interpretation of major structural features in the pre-Tertiary rocks of the region including and surrounding the Nevada Test Site. The thick miogeoclinal section of Late Proterozoic through Lower Permian sedimentary strata records major foreland-vergent thrust faulting, younger hinterland-vergent folding and thrusting, and local extension on low-angle normal faults. In addition, structural discontinuities in the northeastern part of the Nevada Test Site strongly suggest a broad, north-trending zone of sinistral strike-slip faulting that may have had a cumulative offset of many kilometers.

Book Major Structural Controls on the Distribution of Pre Tertiary Rocks Nevada Test Site Vicinity Southern Nevada

Download or read book Major Structural Controls on the Distribution of Pre Tertiary Rocks Nevada Test Site Vicinity Southern Nevada written by and published by . This book was released on 1998 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lateral and vertical distributions of Proterozoic and Paleozoic sedimentary rocks in southern Nevada are the combined products of original stratigraphic relationships and post-depositional faults and folds. This map compilation shows the distribution of the pre-Tertiary rocks in the region including and surrounding the Nevada Test Site. It is based on considerable new evidence from detailed geologic mapping, biostratigraphic control, sedimentological analysis, and a review of regional map relationships. Proterozoic and Paleozoic rocks of the region record paleogeographic transitions between continental shelf depositional environments on the east and deeper-water slope-facies depositional environments on the west. Middle Devonian and Mississippian sequences, in particular, show strong lateral facies variations caused by contemporaneous changes in the western margin of North America during the Antler orogeny. Sections of rock that were originally deposited in widely separated facies localities presently lie in close proximity. These spatial relationships chiefly result from major east- and southeast-directed thrusts that deformed the region in Permian or later time. Somewhat younger contractional structures are identified within two irregular zones that traverse the region. These folds and thrusts typically verge toward the west and northwest and overprint the relatively simple pattern of the older contractional terranes. Local structural complications are significant near these younger structures due to the opposing vergence and due to irregularities in the previously folded and faulted crustal section. Structural and stratigraphic discontinuities are identified on opposing sides of two north-trending fault zones in the central part of the compilation region north of Yucca Flat. The origin and significance of these zones are enigmatic because they are largely covered b Tertiary and younger deposits. These faults most likely results from significant lateral offset, most likely in the sinistral sense. Low-angle normal faults that are at least older than Oligocene, and may pre-date Late Cretaceous time are also present in the region. These faults are shown to locally displace blocks of pre-Tertiary rock by several kilometers. However, none of these structures can be traced for significant distances beyond its outcrop extent, and the inference is made that they do not exert regional influence on the distribution of pre-Tertiary rocks. The extensional strain accommodated by these low-angle normal faults appears to be local and highly irregular. 1 plate.

Book Sub crop Geologic Map of Pre Tertiary Rocks in the Yucca Flat and Northern Frenchman Flat Areas Nevada Test Site Southern Nevada

Download or read book Sub crop Geologic Map of Pre Tertiary Rocks in the Yucca Flat and Northern Frenchman Flat Areas Nevada Test Site Southern Nevada written by and published by . This book was released on 1997 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: This map displays interpreted structural and stratigraphic relations among the Paleozoic and older rocks of the Nevada Test Site region beneath the Miocene volcanic rocks and younger alluvium in the Yucca Flat and northern Frenchman Flat basins. These interpretations are based on a comprehensive examination and review of data for more than 77 drillholes that penetrated part of the pre-Tertiary basement beneath these post-middle Miocene structural basins. Biostratigraphic data from conodont fossils were newly obtained for 31 of these holes, and a thorough review of all prior microfossil paleontologic data is incorporated in the analysis. Subsurface relationships are interpreted in light of a revised regional geologic framework synthesized from detailed geologic mapping in the ranges surrounding Yucca Flat, from comprehensive stratigraphic studies in the region, and from additional detailed field studies on and around the Nevada Test Site. All available data indicate the subsurface geology of Yucca Flat is considerably more complicated than previous interpretations have suggested. The western part of the basin, in particular, is underlain by relics of the eastward-vergent Belted Range thrust system that are folded back toward the west and thrust by local, west-vergent contractional structures of the CP thrust system. Field evidence from the ranges surrounding the north end of Yucca Flat indicate that two significant strike-slip faults track southward beneath the post-middle Miocene basin fill, but their subsurface traces cannot be closely defined from the available evidence. In contrast, the eastern part of the Yucca Flat basin is interpreted to be underlain by a fairly simple north-trending, broad syncline in the pre-Tertiary units. Far fewer data are available for the northern Frenchman Flat basin, but regional analysis indicates the pre-Tertiary structure there should also be relatively simple and not affected by thrusting. This new interpretation has implications for ground water flow through pre-Tertiary rocks beneath the Yucca Flat and northern Frenchman Flat areas, and has consequences for ground water modeling and model validation. Our data indicate that the Mississippian Chainman Shale is not laterally extensive confining unit in the western part of the basin because it is folded back onto itself by the convergent structures of the Belted Range and CP thrust systems. Early and Middle Paleozoic limestone and dolomite are present beneath most of both basins and, regardless of structural complications, are interpreted to form a laterally continuous and extensive carbonate aquifer. Structural culmination that marks the French Peak accommodation zone along the topographic divide between the two basins provides a lateral pathway through highly fractured rock between the volcanic aquifers of Yucca Flat and the regional carbonate aquifer. This pathway may accelerate the migration of ground-water contaminants introduced by underground nuclear testing toward discharge areas beyond the Nevada Test Site boundaries. Predictive three-dimensional models of hydrostratigraphic units and ground-water flow in the pre-Tertiary rocks of subsurface Yucca Flat are likely to be unrealistic due to the extreme structural complexities. The interpretation of hydrologic and geochemical data obtained from monitoring wells will be difficult to extrapolate through the flow system until more is known about the continuity of hydrostratigraphic units. 1 plate.

Book U S Geological Survey Professional Paper

Download or read book U S Geological Survey Professional Paper written by and published by . This book was released on 1984 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Geologic Map of Paleozoic Rocks in the Calico Hills Nevada Test Site Southern Nevada

Download or read book Geologic Map of Paleozoic Rocks in the Calico Hills Nevada Test Site Southern Nevada written by and published by . This book was released on 1998 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Calico Hills area in the southwestern part of the Nevada Test Site, Nye County, Nevada, exposes a core of pre-Tertiary rocks surrounded by middle Miocene volcanic strata. This map portrays the very complex relationships among the pre-Tertiary stratigraphic units of the region. The Devonian and Mississippian rocks of the Calico Hills are distinct from age-equivalent carbonate-shelf or submarine-fan strata in other parts of the Nevada Test Site. The Calico Hills strata are interpreted to have been deposited beyond the continental shelf edge from alternating silicic and carbonate clastic sources. Structures of the Calico Hills area record the compounded effects of: (1) eastward-directed, foreland-vergent thrusting; (2) younger folds, kink zones, and thrusts formed by hinterland-vergent deformation toward northwesterly and northerly directions; and (3) low-angle normal faults that displaced blocks of Middle Paleozoic carbonate strata across the contractionally deformed terrane. All of these structures are older than any of the middle Miocene volcanic rocks that were erupted across the Calico Hills.

Book Geologic Map of the Mine Mountain Area Nevada Test Site Southern Nevada

Download or read book Geologic Map of the Mine Mountain Area Nevada Test Site Southern Nevada written by and published by . This book was released on 1998 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Mine Mountain area is a small range of hills on the west side of the central Yucca Flat basin on the Nevada Test Site, Nye County, Nevada. This map portrays the very complex relationships among the pre-Tertiary stratigraphic units of the region. Rocks and structures of the Mine Mountain area record the compounded effects of: (1) eastward-directed, foreland-vergent thrusting; (2) younger folds and thrusts formed by hinterland vergence in a general westerly direction; and (3) low-angle normal faulting formed by extension along a northeast-southwest trend. All of these structures are older than the oldest middle Miocene volcanic rocks that were deposited on the flanks of the Mine Mountain terrane. High-angle faults that post-date these volcanic rocks locally show displacements of several hundred meters, but do not strongly affect patterns in the pre-Tertiary rocks.

Book The Geology and Climatology of Yucca Mountain and Vicinity Southern Nevada and California

Download or read book The Geology and Climatology of Yucca Mountain and Vicinity Southern Nevada and California written by John S. Stuckless and published by Geological Society of America. This book was released on 2007-01-01 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Nevada Test Site Environmental Report 2003 October 2004

Download or read book Nevada Test Site Environmental Report 2003 October 2004 written by and published by . This book was released on 2005 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Mesozoic and Cenozoic Structural Geology of the CP Hills Nevada Test Site Nye County Nevada and Regional Implications

Download or read book Mesozoic and Cenozoic Structural Geology of the CP Hills Nevada Test Site Nye County Nevada and Regional Implications written by and published by . This book was released on 1991 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed mapping and structural analysis of upper Proterozoic and Paleozoic rocks in the CP Hills of the Nevada Test Site, together with analysis of published maps and cross sections and a reconnaissance of regional structural relations indicate that the CP thrust of Barnes and Poole (1968) actually comprises two separate, oppositely verging Mesozoic thrust systems: (1) the west-vergent CP thrust which is well exposed in the CP Hills and at Mine Mountain, and (2) the east-vergent Belted Range thrust located northwest of Yucca Flat. West-vergence of the CP thrust is indicated by large scale west-vergent recumbent folds in both its hangingwall and footwall and by the fact that the CP thrust ramps up section through hangingwall strata toward the northwest. Regional structural relations indicate that the CP thrust forms part of a narrow sigmoidal belt of west-vergent folding and thrusting traceable for over 180 km along strike. The Belted Range thrust represents earlier Mesozoic deformation that was probably related to the Last Chance thrust system in southeastern California, as suggested by earlier workers. A pre-Tertiary reconstruction of the Cordilleran fold and thrust belt in the region between the NTS and the Las Vegas Range bears a close resemblance to other regions of the Cordillera and has important implications for the development of hinterland-vergent deformation as well as for the probable magnitude of Tertiary extension north of Las Vegas Valley. Subsequent to Mesozoic deformation, the CP Hills were disrupted by at least two episodes of Tertiary extensional deformation: (1) an earlier episode represented by pre-middle Miocene low-angle normal faults, and (2) a later, post-11 Ma episode of high-angle normal faulting. Both episodes of extension were related to regional deformation, the latter of which has resulted in the present basin and range topography of the NTS region.

Book New Publications of the Geological Survey

Download or read book New Publications of the Geological Survey written by Geological Survey (U.S.) and published by . This book was released on 1999 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book OF1999 13 Assessment of metallic and mined energy resources in the Yucca Mountain conceptual controlled area Nye County Nevada

Download or read book OF1999 13 Assessment of metallic and mined energy resources in the Yucca Mountain conceptual controlled area Nye County Nevada written by and published by NV Bureau of Mines & Geology. This book was released on with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: