ABSTRACT: Geology of the Basin and Range Province of Nevada and Utah: An Overview
SILBERLING, N. J., and K. M. NICHOLS, U.S. Geological Survey, Denver, CO
The Basin and Range is a regionally extended province characterized by a thinned crust, magmatism, and block faulting. Within Nevada and Utah, important events in its history include (1) late Proterozoic to early Paleozoic continental rifting and consequent development of a thick miogeoclinal wedge, (2) middle and late Paleozoic orogenesis involving flexural loading of the margin by overthrust oceanic rocks and accumulation of foreland deposits, (3) development of an early Mesozoic back-arc basin outboard of the continental margin, (4) episodic and localized plutonism from the early Mesozoic to the Cenozoic, (5) several generations of middle Mesozoic to early Cenozoic
large-scale tectonic contraction and development of fold and thrust belts, and (6) Cenozoic extension with concomitant volcanism. The challenge in unraveling this complex history involves understanding and accommodating the effects of successively older tectonic and magmatic events, starting necessarily with those of Cenozoic age.
Significant unresolved stratigraphic and structural problems include (1) the process or processes of crustal extension, development of extensional basins, recognition of extensional domains and their accommodation boundaries, and the amount of Cenozoic extension across the region, (2) the location and amount of Mesozoic contraction on thrusts of the Sevier hinterland, Eureka belt, and southeast-vergent Jurassic system spatially related to the sialic margin, (3) the nature of Sonoma and Antler orogenesis, respectively of Permian-early Triassic and late Devonian-Mississippian age, and related foreland sedimentation, and (4) the origin of the deflections of the sialic margin in western and northern Nevada.