Jonathan G. Price, Nevada Bureau of Mines and Geology, MS 178, University of Nevada, Reno, Reno, NV 89557
As a welcome and introduction to the GSN Symposium, the excitement of Nevada geology will be illustrated. From the perspective of an economic geologist, Nevada’s geology is the basis of one of the premier gold-mining areas in the world. Hydrothermal systems have also endowed the state with abundant silver, copper, molybdenum, lead, zinc, barite, and other commodities. Unusual geological conditions resulted in the formation of economic concentrations of lithium, magnesite, and specialty clays. Active geothermal systems are being developed for renewable energy that could rival mineral resources in terms of value. A complex tectonic history is shared with much of the rest of western North America. Chemically favorable ore hosts in Paleozoic rocks were thrusted into position and fractured during multiple continental collisions. Episodes of intermediate to silicic magmatism, particularly during Jurassic, Cretaceous, Eocene, and Miocene times, provided plenty of heat to drive hydrothermal systems and opportunities for metals to be derived from the magmas and country rocks. Some of the most productive ore deposits appear to be aligned along narrow trends that may coincide with major fracture systems in the crust. Crustal extension during the last few tens of millions of years formed the basin-and-range topography that exposes hundreds of ore deposits in mountain ranges and buries others below alluvial cover. Our arid climate, caused primarily by the rain shadow of the Sierra Nevada, makes exposures excellent. An expanding urban population challenges geologists to supply adequate water resources and avoid construction-related hazards caused by altered volcanic rocks, gypsum-rich soils, and subsidence due to groundwater withdrawal. High natural abundances of arsenic, selenium, boron, radon, and perhaps tungsten are local environmental concerns that are ultimately related to the abundance of igneous rocks throughout Nevada. Bedrock and surficial geologic data, seismic records, and geodetic data from high-precision GPS measurements are helping us understand earthquake hazards and tectonics at various time scales. While crustal extension accounts for most of the hazard in central and eastern Nevada, strike-slip faulting in the Walker Lane is accommodating about 20% of the motion between the Pacific and North American plates.