Intrusive rock database for the Digital Geologic Map of Utah

Multistage Cenozoic extension of the Albion–Raft River–Grouse Creek metamorphic core complex: Geochronologic and stratigraphic constraints

“…42-34 Ma calc-alkaline inter-mediate to felsic igneous rocks intruded as both shallow-level plutons (the Emigrant Pass plutonic complex) and erupted volcanic sequences (Figs. 12 and 14) (e.g., Compton, 1983;Kistler and Lee, 1989;Brooks et al, 1995;Nutt and Ludington, 2003;Egger et al, 2003). This early magmatism was driven by mantle-derived magmas, which interacted and assimilated signifi cant amounts of crust beneath this region (Fig.…”

“…The Emigrant Pass plutonic complex (Fig. 3) was emplaced at shallow crustal levels (5-10 km) (Egger et al, 2003) and was coeval with the eruption of felsic volcanic rocks (Compton, 1983;Kistler and Lee, 1989;Nutt and Ludington, 2003). To the southeast of the ARG, andesite fl ows, dacite, and rhyolite ignimbrites of the 41-39 Ma northeast Nevada volcanic fi eld represent a comparable suite of magmas (Brooks et al, 1995;Palmer and Mac-Donald, 2002).…”

Metallogeny of the Great Basin: Crustal evolution, fluid flow, and ore deposits

“…The MGB project also has had synergies with several other USGS projects in the Great Basin and adjacent areas, and some investigations were jointly supported by two or more projects and/or involved some of the same individuals. Examples include: the Western Region Surveys and Analysis project that produced digital datasets on mineral deposits, geology, geophysics, and geochemistry (e.g., Nutt and Ludington, 2003;others, 2005, 2006); the Sources of Industrial Minerals in Western States project (e.g., Bliss andothers, 2002, Koski andHein, 2003;Rytuba and others, 2003;Wallace, 2003dWallace, , 2004; the Metals in Brine and Petroleum project that evaluated the role of seafloor discharges of brine and petroleum in the formation of syngenetic ore deposts in sedimentary basins (e.g., Emsbo, 2004;Johnson and Emsbo, 2004); the Geochemical and Isotope Studies of the Evolution of Ore Deposits project that has characterized the stable isotope geochemistry of sulfate minerals in igneous and hydrothermal systems, the gas and noble gas isotope composition of magmatic hydrothermal alunite, and the source of salt in hydrothermal fluids from diverse hydrothermal systems (Rye, 2005;Landis and Rye, 2005;; the Resources and Hazards of Hydrothermal Systems in Cascades Volcanoes project that has elucidated controls on alteration and metallogenesis in the Oligocene-Quaternary Cascades arcs (e.g., John and others, 2003a); a project that investigated the origin, tectonic relations, and manifestations of the Yellowstone hotspot track (e.g., Morgan and others, 2004;Pierce and others, 2004); a project that evaluated the coupling of mechanical, thermal, chemical and hydraulic phenomena in ore formation (e.g., Berger and others, 2005); allied investigations by our Western and Central Region Mineral Resources Team Chief Scientists Connie Nutt and Peter Vikre (Nutt and Hofstra, in press;Vikre andothers, 2003, 2005a,b, in press); and related investigations by colleagues on other projects (e.g., Church and others, 2005). The MGB project also complements two groundwater investigations in the Great Basin: the Hydrogeologic Framework of Aquifer Systems in the Desert Southwest project that addresses ground-water availability (Chuang and others, 2003;Howard and others, in press) and the Basin and Range Carbonate Aquifer System Study (BARCASS) project that is conducting research on regional ground-water flow systems in Nevada and potential impacts from future ground-water pumping (http://nevada.usgs.gov/barcass/i...…”

“…The space-time-compositional evolution of intrusive rocks in the Great Basin is being synthesized to clarify the roles of magma evolution and episodes of magma emplacement in the formation of a variety of pluton-related mineral deposits and to improve digital geologic maps of Utah and Nevada (Nutt and Ludington, 2003;du Bray and Nash, 2005;du Bray and others, in press;Crafford, in press). This work also has contributed to the development of a metamorphic map of California (Day and others, 2003).…”