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D. L. Hoover

Publications and source records attributed to D. L. Hoover.

11 recordsLinked to original sources
USGS1983

Geology of faults exposed in trenches in Crater Flat, Nye County, Nevada

Study of three trenches excavated across two faults along the eastern edge of Crater Flat indicates that the main fault movement offset unit QTa in trench 1 at least 2.4 m down to the west, and occurred about 1.1 m.y. ago, as indicated by included basalt ash. Later fault movement, detected in trench 3, and probably related to the faulting at trench 1, displaced unit Q2c a combined distance of 0.8 m down to the west along three faults. Fault movement at trench 3 occurred sometime after 260,000 years ago and before about 40,000 years, but the evidence favors an age that is closer to the older date.

Open-File Report↗
USGS1978

Potential sites for a spent unreprocessed fuel facility (SURFF), southwestern part of the Nevada Test Site

In the absence of specific criteria, the topography, geomorphology, and geology of Jackass Flats and vicinity in the southwestern part of the Nevada Test Site are evaluated by arbitrary guidelines for a Spent Unreprocessed Fuel Facility. The guidelines include requirements for surface slopes of less than 5 percent, 61 m of alluvium beneath the site, an area free of active erosion or deposition, lack of faults, a minimum area of 5 km2, no potential for flooding, and as many logistical support facilities as possible. The geology of the Jackass Flats area is similar to the rest of the Nevada Test Site in topographic relief (305-1,200 m), stratigraphy (complexly folded and faulted Paleozoic sediments overlain by Tertiary ash-flow tuffs and lavas overlain in turn by younger alluvium), and structure (Paleozoic thrust faults and folds, strike-slip faults, proximity to volcanic centers, and Basin and Range normal faults). Of the stratigraphic units at the potential Spent Unreprocessed Fuel Facility site in Jackass Flats, only the thickness and stability of the alluvium are of immediate importance. Basin and Range faults and a possible extension of the Mine Mountain fault need further investigation. The combination of a slope map and a simplified geologic and physiographic map into one map shows several potential sites for a Spent Unreprocessed Fuel Facility in Jackass Flats. The potential areas have slopes of less than 5 percent and contain only desert pavement or segmented desert pavement--the two physiographic categories having the greatest geomorphic and hydraulic stability. Before further work can be done, specific criteria for a Spent Unreprocessed Fuel Facility site must be defined. Following criteria definition, potential sites will require detailed topographic and geologic studies, subsurface investigations (including geophysical methods, trenching, and perhaps shallow drilling for faults in alluvium), detailed surface hydrologic studies, and possibly subsurface hydrologic studies.

Nevada↗
USGS1968

Subsurface geology of the Silent Canyon caldera, Nevada Test Site, Nevada

Deep drilling in the vicinity of Silent Canyon on eastern Pahute Mesa, Nevada, has revealed a Tertiary volcanic section locally thicker than 14,000 feet. The area drilled covers most of the Silent Canyon caldera and some of the surrounding area. The caldera is rudely elliptical in plan and measures 10 by 14 miles. Except on its east edge, the caldera is completely obscured by younger volcanic rocks, including ash-flow sheets from several other centers. The structure, originally inferred from surface mapping and a 20-mgal gravity low, has been confirmed by drilling at 21 sites. Petrographic, chemical, and magnetic studies of more than 4,000 feet of drill core have revealed a complex sequence of volcanic rocks. Precaldera rocks include thick talc-alkalic lavas and tuffs. Peralkaline lavas and tuffs of the Silent Canyon center include the Belted Range Tuff (13-14 m.y.), eruption of which resulted in caldera collapse. The Belted Range Tuff has been downdropped 5,000-7,000 feet in the caldera. Subsequently, the depression was partially filled in the eastern part by genetically related peralkaline lavas and tuffs and in the western part by later calc -alkaline lavas and tuffs apparently genetically unrelated to the peralkaline rocks of the Silent Canyon center. Renewed subsidence probably occurred during their eruption. Isopach maps of younger tuffs show that the caldera was topographically low during deposition of later (12.5-7 m.y.) ash-flow sheets from other volcanic centers.

Nevada↗