Tertiary extension north of the Las Vegas Valley shear zone, Sheep and Desert Ranges, Clark County, Nevada

摘要

Detailed mapping reveals the presence of high-angle extensional faults and low-angle gravity slides on the west side of the Sheep Range. Three major high-angle faulting events each account for 20° of eastward rotation and accommodate extension between the Las Vegas Range and the Desert Range. Low-angle faults represent surficial slides in response to topography produced by extension on the high-angle faults. Faulting took place during the Miocene, synchronously with deposition of the Horse Spring Formation and with displacement on the Las Vegas Valley shear zone. The extension in the Sheep Range took place without volcanism, intrusion, or metamorphism of the Paleozoic sedimentary rocks.