David A John
David is a Scientist Emeritus with the Geology, Minerals, Energy, and Geophysics Science Center
Science and Products
Magmatic-Tectonic History and Component Sources of Major Precious Metal Deposits in the Tonopah, Goldfield, and Comstock Lode Districts, NV
Project objectives are refinement of stratigraphy, structure, and magmatic-hydrothermal evolution of the Tonopah, Goldfield, and Comstock Lode districts, and determination of the sources of hydrothermal mineral components. Results are expected to include refined geologic and tectonic maps of important districts in the Walker Lane, reduced uncertainty in sources of elements in ore deposits...
Geochemical data for the Thunder Mountain volcanic field and dikes in the Stibnite-Yellow Pine district region
This dataset contains whole rock geochemical data for volcanic rocks, both extrusive rocks of the western part of the Thunder Mountain volcanic field and hypabyssal dikes in the Stibnite-Yellow Pine district and in the Pistol Creek dike swarm, which are in central Idaho. Major oxides and trace elements are included, which are reported as percentages and parts per million, respectively. Major oxide
Zircon U-Pb age and trace element data for igneous rocks in the Cortez area, Nevada
The Cortez region in north-central Nevada hosts the second largest concentration of Carlin-type gold deposits in Nevada. The origin of these deposits is debated, and major questions remain concerning the role of magmatism in their formation. To understand the Mesozoic and Cenozoic magmatic history of the Cortez region, twenty-one samples of igneous rocks ranging from Jurassic to Eocene were sample
Geochemical and geochronologic data from the Stillwater Range, Clan Alpine, and Desatoya Mountains, Nevada (ver. 3.0, December 2023)
This dataset contains argon-argon and U-Pb geochronologic data collected from igneous rocks in the Stillwater Range, Clan Alpine, and Desatoya Mountains, western Nevada, USA.
Data to accompany U.S. Geological Survey Data Series 1099: Petrographic, geochemical and geochronologic data for Cenozoic volcanic rocks of the Tonopah, Divide, and Goldfield Mining Districts, Nevada
This dataset is the assembled analytical results of geochemical, petrographic, and geochronologic data for samples, principally those of unmineralized Tertiary volcanic rocks, from the Tonopah, Divide, and Goldfield mining districts of west-central Nevada. Much of the data presented here for the Tonopah and Divide districts are for samples collected by Bonham and Garside (1979) during geologic map
Geochemical and Geochronological Data for Hydrothermal Systems on Brokeoff Volcano and in the Maidu Volcanic Center, Lassen Peak area, northeastern California
This dataset contains 8 data tables provided in csv format that contain sample location data, whole-rock geochemical data, argon-argon geochronologic data, sulfur, oxygen, and hydrogen isotope data, and mineralogical data from shortwave infrared spectrography (SWIR) and X-ray diffraction (XRD) analyses collected from igneous rocks on Brokeoff and Maidu volcanoes, northeastern California, USA. The
GIS and Data Tables for Focus Areas for Potential Domestic Nonfuel Sources of Rare Earth Elements
In response to Executive Order 13817 of December 20, 2017, the U.S. Geological Survey (USGS) coordinated with the Bureau of Land Management (BLM) to identify 35 nonfuel minerals or mineral materials considered critical to the economic and national security of the United States (U.S.). Acquiring information on possible domestic sources of these critical minerals is the basis of the USGS Earth Mappi
Locatable Mineral Assessment Tracts for the U.S. Geological Survey Sagebrush Mineral Resource Assessment Project
The polygon (vector) feature class represents locatable mineral resource assessment tracts (tracts of land) associated with the Department of the Interior (DOI) Sagebrush Focal Areas in Montana, Wyoming and Utah, central Idaho, and the Oregon-Nevada-Idaho border area. The mineral resources tracts are geographic areas that were assessed by the U.S. Geological Survey (USGS) and were determined to be
Geologic map of the Bodie Hills, California and Nevada
The Bodie Hills covers about 1,200 km2 straddling the California-Nevada state boundary just north of Mono Lake in the western part of the Basin and Range Province, about 20 km east of the central Sierra Nevada. The area is mostly underlain by the partly overlapping, middle to late Miocene Bodie Hills volcanic field and Pliocene to late Pleistocene Aurora volcanic field (John and others, 2012). Upp
Geologic map of the Caetano caldera, Lander and Eureka counties, Nevada
The Eocene (34 Ma) Caetano caldera in north-central
Nevada offers an exceptional opportunity to study the
physical and petrogenetic evolution of a large (20 km by
10–18 km pre-extensional dimensions) silicic magma
chamber, from precursor magmatism to caldera collapse
and intrusion of resurgent plutons. Caldera-related rocks
shown on this map include two units of crystal-rich
intracaldera tu
Geologic Map of the Izzenhood Spring Quadrangle, Lander County, Nevada
The Izzenhood Spring quadrangle covers about 145 km2 of the southwestern part of the Sheep Creek Range in northern Lander County, Nevada. The quadrangle is underlain by Lower Paleozoic rocks that are unconformably overlain and intruded by thick sequences of Miocene igneous rocks related to the northern Nevada rift (Stewart and McKee, 1977; Wallace and John, 1998; John and others, 2000). Much of th
Geologic map of the Freel Peak 15-minute Quadrangle, California and Nevada
No abstract available.
Filter Total Items: 60
Critical minerals in subduction-related magmatic-hydrothermal systems of the United States
During the World War and Cold War eras (1910s–1990s), domestic consumption of numerous mineral commodities relied increasingly on imported supplies. Consumption reliance has since expanded to include 50 “critical minerals” (elements and mineral commodities) that are mostly to entirely imported and subject to curtailment by suppliers or supply chain disruption. New domestic supplies of critical min
Authors
Peter Vikre, David John, Niki E. Wintzer, Fleetwood Koutz, Frederick Graybeal, Chris Dail, David C. Annis
Timing of rhyolite intrusion and Carlin-type gold mineralization at the Cortez Hills Carlin-type deposit, Nevada, USA
Carlin-type gold deposits (CTDs) of Nevada are the largest producers of gold in the United States, a leader in world gold production. Although much has been resolved about the characteristics and origin of CTDs in Nevada, major questions remain, especially about (1) the role of magmatism, whether only a source of heat or also metals, (2) whether CTDs only formed in the Eocene, and (3) whether pre-
Authors
Christopher D. Henry, David John, Robert W. Leonardson, William T McIntosh, Matt T. Heizler, Joseph Colgan, Kathryn E. Watts
Porphyry and epithermal mineral deposits
Porphyry and epithermal mineral deposits form large economic ore bodies that provide the global economy with copper, molybdenum, gold, silver and other byproducts (Re, Te, Se). They form in the upper crust and are related to sulfur- and water-rich intermediate to silicic magmatic sources of hydrothermal fluids that move upward and produce extensive hydrolytic and alkali wall-rock alteration, quart
Authors
John H Dilles, David John
Why did Great Basin Eocene magmatism generate Carlin-type gold deposits when extensive Jurassic to Middle Miocene magmatism did not? Lessons from the Cortez Region, Northern Nevada, USA
No abstract available.
Authors
Christopher D. Henry, David John, Matt T. Heizler, Robert W. Leonardson, Joseph Colgan, Kathryn E. Watts, Michael W. Ressel, Brian L. Cousens
Petrology of volcanic rocks associated with silver-gold (Ag-Au) epithermal deposits in the Tonopah, Divide, and Goldfield Mining Districts, Nevada
Miocene calc-alkaline volcanic rocks, part of the southern segment of the ancestral Cascades magmatic arc, are spatially, temporally, and likely genetically associated with precious metal epithermal deposits in the Tonopah, Divide, and Goldfield Districts of west-central Nevada. In the Tonopah mining district, volcanic rocks include the Mizpah Trachyte, Fraction Tuff, and Oddie Rhyolite; in the Di
Authors
Edward A. du Bray, David John, Joseph Colgan, Peter G. Vikre, Michael A. Cosca, Leah E. Morgan
Petrographic, geochemical, and geochronologic data for cenozoic volcanic rocks of the Tonopah, Divide, and Goldfield Mining Districts, Nevada
The purpose of this report is to summarize geochemical, petrographic, and geochronologic data for samples, principally those of unmineralized Tertiary volcanic rocks, from the Tonopah, Divide, and Goldfield mining districts of west-central Nevada (fig. 1). Much of the data presented here for the Tonopah and Divide districts are for samples collected by Bonham and Garside (1979) during geologic map
Authors
Edward A. du Bray, David John, Peter G. Vikre, Joseph Colgan, Michael A. Cosca, Leah E. Morgan, Robert J. Fleck, Wayne R. Premo, Christopher S. Holm-Denoma
Pleistocene hydrothermal activity on Brokeoff volcano and in the Maidu volcanic center, Lassen Peak area, northeast California: Evolution of magmatic-hydrothermal systems on stratovolcanoes
Partially eroded stratovolcanoes worldwide, notably Mounts Rainier and Adams in the Cascades and several volcanoes in Japan, record episodic periods of eruption and geothermal activity that produce zones of hydrothermal alteration. The partly eroded core of late Pleistocene Brokeoff volcano on the south side of Lassen Peak exposes the upper 1 km of multiple ancient (ca. 410–300 ka) magmatic-hydrot
Authors
David John, Robert G. Lee, George N. Breit, John H. Dilles, Andrew T. Calvert, L. J. Patrick Muffler, Michael A. Clynne
Igneous rocks in the Fish Creek Mountains and environs, Battle Mountain area, north-central Nevada: A microcosm of Cenozoic igneous activity in the northern Great Basin, Basin and Range Province, USA
The Great Basin of the western United States, the northern component of the Basin and Range Province, is a region of Cenozoic lithospheric extension with multiple periods and types of igneous activity. The composition and volume of Cenozoic magmas reflect a complex interaction between mantle-derived magmas and highly diverse crust, where both mantle sources and magmatic processes were modulated by
Authors
Brian L. Cousens, Christopher D. Henry, Christopher Stevens, Susan Varve, David John, Stacey Wetmore
Oxygen isotopic investigation of silicic magmatism in the Stillwater caldera complex, Nevada: Generation of large-volume, low-δ18O rhyolitic tuffs and assessment of their regional context in the Great Basin of the western United States
Successive caldera-forming eruptions from ca. 30 to 25 Ma generated a large nested caldera complex in western Nevada that was subsequently dissected by Basin and Range extension, providing extraordinary cross-sectional views through diverse volcanic and plutonic rocks. A high-resolution oxygen isotopic study was conducted on units that represent all major parts of the Job Canyon, Louderback Mounta
Authors
Kathryn E. Watts, David John, Joseph Colgan, Christopher D. Henry, Ilya N. Bindeman, John W. Valley
The Miocene Atastra Creek sinter (Bodie Hills volcanic field, California and Nevada): 4D evolution of a geomorphically intact siliceous hot spring deposit
The Atastra Creek siliceous hot spring deposit, or sinter, occurs in the Paramount-Bald Peak alteration zone, due north of the Bodie precious metals mining district in the Miocene Bodie Hills volcanic field, California and Nevada, U.S.A. Distinctive features include its geomorphically intact geyser vent mounds, the presence of growth-fault-stepped sinter terraces that developed westward along a NN
Authors
Kathleen A. Campbell, Diego M. Guido, David John, Peter Vikre, David Rhys, Ayrton Hamilton
Descriptive models for epithermal gold-silver deposits
Epithermal gold-silver deposits are vein, stockwork, disseminated, and replacement deposits that are mined primarily for their gold and silver contents; some deposits also contain substantial resources of lead, zinc, copper, and (or) mercury. These deposits form in the uppermost parts of the crust, at depths less than about 1,500 meters below the water table, and at temperatures below about 300 °C
Authors
David John, Peter G. Vikre, Edward A. du Bray, Richard J. Blakely, David L. Fey, Barnaby W. Rockwell, Jeffrey L. Mauk, Eric D. Anderson, Frederick Graybeal
By
Ecosystems Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Geophysics, and Geochemistry Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Western Fisheries Research Center, Central Energy Resources Science Center
Insights into the emplacement of upper-crustal plutons and their relationship to large silicic calderas, from field relationships, geochronology, and zircon trace element geochemistry in the Stillwater – Clan Alpine caldera complex, western Nevada, USA
Geologic mapping, new U-Pb zircon ages, and new and published 40Ar/39Ar sanidine ages document the timing and extent of Oligocene magmatism in the southern Stillwater Range and Clan Alpine Mountains of western Nevada, where Miocene extension has exposed at least six nested silicic calderas and underlying granitic plutons to crustal depths locally ≥ 9 km. Both caldera-forming rhyolitic tuffs and un
Authors
Joseph Colgan, David John, Christopher D. Henry, Kathryn E. Watts
Science and Products
- Science
Magmatic-Tectonic History and Component Sources of Major Precious Metal Deposits in the Tonopah, Goldfield, and Comstock Lode Districts, NV
Project objectives are refinement of stratigraphy, structure, and magmatic-hydrothermal evolution of the Tonopah, Goldfield, and Comstock Lode districts, and determination of the sources of hydrothermal mineral components. Results are expected to include refined geologic and tectonic maps of important districts in the Walker Lane, reduced uncertainty in sources of elements in ore deposits... - Data
Geochemical data for the Thunder Mountain volcanic field and dikes in the Stibnite-Yellow Pine district region
This dataset contains whole rock geochemical data for volcanic rocks, both extrusive rocks of the western part of the Thunder Mountain volcanic field and hypabyssal dikes in the Stibnite-Yellow Pine district and in the Pistol Creek dike swarm, which are in central Idaho. Major oxides and trace elements are included, which are reported as percentages and parts per million, respectively. Major oxideZircon U-Pb age and trace element data for igneous rocks in the Cortez area, Nevada
The Cortez region in north-central Nevada hosts the second largest concentration of Carlin-type gold deposits in Nevada. The origin of these deposits is debated, and major questions remain concerning the role of magmatism in their formation. To understand the Mesozoic and Cenozoic magmatic history of the Cortez region, twenty-one samples of igneous rocks ranging from Jurassic to Eocene were sampleGeochemical and geochronologic data from the Stillwater Range, Clan Alpine, and Desatoya Mountains, Nevada (ver. 3.0, December 2023)
This dataset contains argon-argon and U-Pb geochronologic data collected from igneous rocks in the Stillwater Range, Clan Alpine, and Desatoya Mountains, western Nevada, USA.Data to accompany U.S. Geological Survey Data Series 1099: Petrographic, geochemical and geochronologic data for Cenozoic volcanic rocks of the Tonopah, Divide, and Goldfield Mining Districts, Nevada
This dataset is the assembled analytical results of geochemical, petrographic, and geochronologic data for samples, principally those of unmineralized Tertiary volcanic rocks, from the Tonopah, Divide, and Goldfield mining districts of west-central Nevada. Much of the data presented here for the Tonopah and Divide districts are for samples collected by Bonham and Garside (1979) during geologic mapGeochemical and Geochronological Data for Hydrothermal Systems on Brokeoff Volcano and in the Maidu Volcanic Center, Lassen Peak area, northeastern California
This dataset contains 8 data tables provided in csv format that contain sample location data, whole-rock geochemical data, argon-argon geochronologic data, sulfur, oxygen, and hydrogen isotope data, and mineralogical data from shortwave infrared spectrography (SWIR) and X-ray diffraction (XRD) analyses collected from igneous rocks on Brokeoff and Maidu volcanoes, northeastern California, USA. TheGIS and Data Tables for Focus Areas for Potential Domestic Nonfuel Sources of Rare Earth Elements
In response to Executive Order 13817 of December 20, 2017, the U.S. Geological Survey (USGS) coordinated with the Bureau of Land Management (BLM) to identify 35 nonfuel minerals or mineral materials considered critical to the economic and national security of the United States (U.S.). Acquiring information on possible domestic sources of these critical minerals is the basis of the USGS Earth MappiLocatable Mineral Assessment Tracts for the U.S. Geological Survey Sagebrush Mineral Resource Assessment Project
The polygon (vector) feature class represents locatable mineral resource assessment tracts (tracts of land) associated with the Department of the Interior (DOI) Sagebrush Focal Areas in Montana, Wyoming and Utah, central Idaho, and the Oregon-Nevada-Idaho border area. The mineral resources tracts are geographic areas that were assessed by the U.S. Geological Survey (USGS) and were determined to be - Maps
Geologic map of the Bodie Hills, California and Nevada
The Bodie Hills covers about 1,200 km2 straddling the California-Nevada state boundary just north of Mono Lake in the western part of the Basin and Range Province, about 20 km east of the central Sierra Nevada. The area is mostly underlain by the partly overlapping, middle to late Miocene Bodie Hills volcanic field and Pliocene to late Pleistocene Aurora volcanic field (John and others, 2012). UppGeologic map of the Caetano caldera, Lander and Eureka counties, Nevada
The Eocene (34 Ma) Caetano caldera in north-central Nevada offers an exceptional opportunity to study the physical and petrogenetic evolution of a large (20 km by 10–18 km pre-extensional dimensions) silicic magma chamber, from precursor magmatism to caldera collapse and intrusion of resurgent plutons. Caldera-related rocks shown on this map include two units of crystal-rich intracaldera tuGeologic Map of the Izzenhood Spring Quadrangle, Lander County, Nevada
The Izzenhood Spring quadrangle covers about 145 km2 of the southwestern part of the Sheep Creek Range in northern Lander County, Nevada. The quadrangle is underlain by Lower Paleozoic rocks that are unconformably overlain and intruded by thick sequences of Miocene igneous rocks related to the northern Nevada rift (Stewart and McKee, 1977; Wallace and John, 1998; John and others, 2000). Much of thGeologic map of the Freel Peak 15-minute Quadrangle, California and Nevada
No abstract available. - Publications
Filter Total Items: 60
Critical minerals in subduction-related magmatic-hydrothermal systems of the United States
During the World War and Cold War eras (1910s–1990s), domestic consumption of numerous mineral commodities relied increasingly on imported supplies. Consumption reliance has since expanded to include 50 “critical minerals” (elements and mineral commodities) that are mostly to entirely imported and subject to curtailment by suppliers or supply chain disruption. New domestic supplies of critical minAuthorsPeter Vikre, David John, Niki E. Wintzer, Fleetwood Koutz, Frederick Graybeal, Chris Dail, David C. AnnisTiming of rhyolite intrusion and Carlin-type gold mineralization at the Cortez Hills Carlin-type deposit, Nevada, USA
Carlin-type gold deposits (CTDs) of Nevada are the largest producers of gold in the United States, a leader in world gold production. Although much has been resolved about the characteristics and origin of CTDs in Nevada, major questions remain, especially about (1) the role of magmatism, whether only a source of heat or also metals, (2) whether CTDs only formed in the Eocene, and (3) whether pre-AuthorsChristopher D. Henry, David John, Robert W. Leonardson, William T McIntosh, Matt T. Heizler, Joseph Colgan, Kathryn E. WattsPorphyry and epithermal mineral deposits
Porphyry and epithermal mineral deposits form large economic ore bodies that provide the global economy with copper, molybdenum, gold, silver and other byproducts (Re, Te, Se). They form in the upper crust and are related to sulfur- and water-rich intermediate to silicic magmatic sources of hydrothermal fluids that move upward and produce extensive hydrolytic and alkali wall-rock alteration, quartAuthorsJohn H Dilles, David JohnWhy did Great Basin Eocene magmatism generate Carlin-type gold deposits when extensive Jurassic to Middle Miocene magmatism did not? Lessons from the Cortez Region, Northern Nevada, USA
No abstract available.AuthorsChristopher D. Henry, David John, Matt T. Heizler, Robert W. Leonardson, Joseph Colgan, Kathryn E. Watts, Michael W. Ressel, Brian L. CousensPetrology of volcanic rocks associated with silver-gold (Ag-Au) epithermal deposits in the Tonopah, Divide, and Goldfield Mining Districts, Nevada
Miocene calc-alkaline volcanic rocks, part of the southern segment of the ancestral Cascades magmatic arc, are spatially, temporally, and likely genetically associated with precious metal epithermal deposits in the Tonopah, Divide, and Goldfield Districts of west-central Nevada. In the Tonopah mining district, volcanic rocks include the Mizpah Trachyte, Fraction Tuff, and Oddie Rhyolite; in the DiAuthorsEdward A. du Bray, David John, Joseph Colgan, Peter G. Vikre, Michael A. Cosca, Leah E. MorganPetrographic, geochemical, and geochronologic data for cenozoic volcanic rocks of the Tonopah, Divide, and Goldfield Mining Districts, Nevada
The purpose of this report is to summarize geochemical, petrographic, and geochronologic data for samples, principally those of unmineralized Tertiary volcanic rocks, from the Tonopah, Divide, and Goldfield mining districts of west-central Nevada (fig. 1). Much of the data presented here for the Tonopah and Divide districts are for samples collected by Bonham and Garside (1979) during geologic mapAuthorsEdward A. du Bray, David John, Peter G. Vikre, Joseph Colgan, Michael A. Cosca, Leah E. Morgan, Robert J. Fleck, Wayne R. Premo, Christopher S. Holm-DenomaPleistocene hydrothermal activity on Brokeoff volcano and in the Maidu volcanic center, Lassen Peak area, northeast California: Evolution of magmatic-hydrothermal systems on stratovolcanoes
Partially eroded stratovolcanoes worldwide, notably Mounts Rainier and Adams in the Cascades and several volcanoes in Japan, record episodic periods of eruption and geothermal activity that produce zones of hydrothermal alteration. The partly eroded core of late Pleistocene Brokeoff volcano on the south side of Lassen Peak exposes the upper 1 km of multiple ancient (ca. 410–300 ka) magmatic-hydrotAuthorsDavid John, Robert G. Lee, George N. Breit, John H. Dilles, Andrew T. Calvert, L. J. Patrick Muffler, Michael A. ClynneIgneous rocks in the Fish Creek Mountains and environs, Battle Mountain area, north-central Nevada: A microcosm of Cenozoic igneous activity in the northern Great Basin, Basin and Range Province, USA
The Great Basin of the western United States, the northern component of the Basin and Range Province, is a region of Cenozoic lithospheric extension with multiple periods and types of igneous activity. The composition and volume of Cenozoic magmas reflect a complex interaction between mantle-derived magmas and highly diverse crust, where both mantle sources and magmatic processes were modulated byAuthorsBrian L. Cousens, Christopher D. Henry, Christopher Stevens, Susan Varve, David John, Stacey WetmoreOxygen isotopic investigation of silicic magmatism in the Stillwater caldera complex, Nevada: Generation of large-volume, low-δ18O rhyolitic tuffs and assessment of their regional context in the Great Basin of the western United States
Successive caldera-forming eruptions from ca. 30 to 25 Ma generated a large nested caldera complex in western Nevada that was subsequently dissected by Basin and Range extension, providing extraordinary cross-sectional views through diverse volcanic and plutonic rocks. A high-resolution oxygen isotopic study was conducted on units that represent all major parts of the Job Canyon, Louderback MountaAuthorsKathryn E. Watts, David John, Joseph Colgan, Christopher D. Henry, Ilya N. Bindeman, John W. ValleyThe Miocene Atastra Creek sinter (Bodie Hills volcanic field, California and Nevada): 4D evolution of a geomorphically intact siliceous hot spring deposit
The Atastra Creek siliceous hot spring deposit, or sinter, occurs in the Paramount-Bald Peak alteration zone, due north of the Bodie precious metals mining district in the Miocene Bodie Hills volcanic field, California and Nevada, U.S.A. Distinctive features include its geomorphically intact geyser vent mounds, the presence of growth-fault-stepped sinter terraces that developed westward along a NNAuthorsKathleen A. Campbell, Diego M. Guido, David John, Peter Vikre, David Rhys, Ayrton HamiltonDescriptive models for epithermal gold-silver deposits
Epithermal gold-silver deposits are vein, stockwork, disseminated, and replacement deposits that are mined primarily for their gold and silver contents; some deposits also contain substantial resources of lead, zinc, copper, and (or) mercury. These deposits form in the uppermost parts of the crust, at depths less than about 1,500 meters below the water table, and at temperatures below about 300 °CAuthorsDavid John, Peter G. Vikre, Edward A. du Bray, Richard J. Blakely, David L. Fey, Barnaby W. Rockwell, Jeffrey L. Mauk, Eric D. Anderson, Frederick GraybealByEcosystems Mission Area, Energy Resources Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Geophysics, and Geochemistry Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Western Fisheries Research Center, Central Energy Resources Science CenterInsights into the emplacement of upper-crustal plutons and their relationship to large silicic calderas, from field relationships, geochronology, and zircon trace element geochemistry in the Stillwater – Clan Alpine caldera complex, western Nevada, USA
Geologic mapping, new U-Pb zircon ages, and new and published 40Ar/39Ar sanidine ages document the timing and extent of Oligocene magmatism in the southern Stillwater Range and Clan Alpine Mountains of western Nevada, where Miocene extension has exposed at least six nested silicic calderas and underlying granitic plutons to crustal depths locally ≥ 9 km. Both caldera-forming rhyolitic tuffs and unAuthorsJoseph Colgan, David John, Christopher D. Henry, Kathryn E. Watts