Gravity and magnetic study of the Pahute Mesa and Oasis Valley region, Nye County, Nevada

摘要: Regional gravity and aeromagnetic maps reveal the existence of deep basins underlying much southwestern Nevada volcanic field, approximately 150 km northwest Las Vegas. These also indicate presence prominent features (geophysical lineaments) within beneath basin fill. Detailed surveys were conducted in order to characterize nature boundaries, delineate additional subsurface features, evaluate their possible influence on movement ground water. Geophysical modeling data indicates that many may be related processes caldera formation. Collapse various calderas field resulted dense basement rocks occurring at greater depths boundaries. Modeling collapse occurred along faults are arcuate steeply dipping. There indications western Pahute Mesa - Oasis Valley region consists predominantly granitic and/or fine-grained siliceous sedimentary less permeable ground-water flow than fractured carbonate rock east southeast study area. The northeast-trending Thirsty Canyon lineament, expressed thickness maps, separates from intracaldera accumulations Silent Timber Mountain complexes. sources lineament is an 2-km wide ring fracture system with step-like differential displacements, perhaps localized a pre-existing Basin Range fault. Due vertical offsets, zone probably juxtaposes types different permeability and, thus, it act as barrier deflect its flanks toward Valley. Within fault zone, highly serve conduit, depending upon degree alteration effect porosity permeability. In region, other structures include southern boundaries basin, where abruptly shallows.