David A John
David is a Scientist Emeritus with the Geology, Minerals, Energy, and Geophysics Science Center
Science and Products
Filter Total Items: 60
Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada
Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada
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This report presents petrographic and geochemical data for samples collected during investigations of Tertiary volcanism in the Bodie Hills of California and Nevada. Igneous rocks in the area are principally 15–6 Ma subduction-related volcanic rocks of the Bodie Hills volcanic
Authors
Edward A. du Bray, David John, Stephen E. Box, Peter G. Vikre, Robert J. Fleck, Brian L. Cousens
Miocene magmatism in the Bodie Hills volcanic field, California and Nevada: A long-lived eruptive center in the southern segment of the ancestral Cascades arc
The Middle to Late Miocene Bodie Hills volcanic field is a >700 km2, long-lived (∼9 Ma) but episodic eruptive center in the southern segment of the ancestral Cascades arc north of Mono Lake (California, U.S.). It consists of ∼20 major eruptive units, including 4 trachyandesite stratovolcanoes emplaced along the margins of the field, and numerous, more centrally located silicic trachyandesite to rh
Authors
David John, Edward A. du Bray, Richard J. Blakely, Robert J. Fleck, Peter G. Vikre, Stephen E. Box, Barry C. Moring
Epithermal gold-silver deposits of the Hauraki Goldfield, New Zealand: An introduction
No abstract available.
Authors
David John
Petrologic, tectonic, and metallogenic evolution of the Ancestral Cascades magmatic arc, Washington, Oregon, and northern California
Present-day High Cascades arc magmatism was preceded by ∼40 m.y. of nearly cospatial magmatism represented by the ancestral Cascades arc in Washington, Oregon, and northernmost California (United States). Time-space-composition relations for the ancestral Cascades arc have been synthesized from a recent compilation of more than 4000 geochemical analyses and associated age data. Neither the composi
Authors
Edward A. du Bray, David John
Episodic intrusion, internal differentiation, and hydrothermal alteration of the Miocene Tatoosh intrusive suite south of Mount Rainier, Washington
The Miocene Tatoosh intrusive suite south of Mount Rainier is composed of three broadly granodioritic plutons that are manifestations of ancestral Cascades arc magmatism. Tatoosh intrusive suite plutons have individually diagnostic characteristics, including texture, mineralogy, and geochemistry, and apparently lack internal contacts. New ion-microprobe U-Pb zircon ages indicate crystallization of
Authors
Edward A. du Bray, Charles R. Bacon, David John, Joseph L. Wooden, Frank K. Mazdab
Hydrothermal alteration of the Late Eocene Caetano ash-flow caldera, north-central Nevada: A field and ASTER remote sensing study
Geologic mapping and analysis of ASTER remote sensing data were used to define the effects of a large hydrothermal system in the 12–18 by 22 km Caetano caldera. The caldera formed at ~33.8Ma during eruption of >1100km3 of the rhyolitic Caetano Tuff that left a 1 km deep basin which was partly filled by a lake. Magma resurgence resulted in shallow(<1 km) emplacement of the Redrock Canyon granite po
Authors
David John, Barnaby W. Rockwell, Christopher D. Henry, Joseph Colgan
Porphyry copper deposit model
This report contains a revised descriptive model of porphyry copper deposits (PCDs), the world's largest source (about 60 percent) and resource (about 65 percent) of copper and a major source of molybdenum, gold and silver. Despite relatively low grades (average 0.44 percent copper in 2008), PCDs have significant economic and societal impacts due to their large size (commonly hundreds of millions
Authors
Robert A. Ayuso, Mark D. Barton, Richard J. Blakely, Robert J. Bodnar, John H. Dilles, Floyd Gray, Fred T. Graybeal, John L. Mars, Darcy McPhee, Robert R. Seal, Ryan D. Taylor, Peter G. Vikre
Mineral-resource assessment of northern Nye County, Nevada— A progress report
The U.S. Geological Survey (USGS), University of Nevada, Las Vegas (UNLV), and Nevada Bureau of Mines and Geology (NBMG), which is a part of the University of Nevada, Reno (UNR), have completed the first year of data collection and analysis in preparation for a new mineral- and energy-resource assessment of northern Nye County, Nevada. This report provides information about work completed before O
Authors
Steve Ludington, David John, John L. Muntean, Andrew D. Hanson, Stephen B. Castor, Christopher D. Henry, Niki Wintzer, Jean S. Cline, Adam C. Simon
Geochemical database for igneous rocks of the ancestral Cascades Arc— Southern segment, California and Nevada
Volcanic rocks that form the southern segment of the Cascades magmatic arc are an important manifestation of Cenozoic subduction and associated magmatism in western North America. Until recently, these rocks had been little studied and no systematic compilation of existing composition data had been assembled. This report is a compilation of all available chemical data for igneous rocks that consti
Authors
Edward A. du Bray, David John, Keith Putirka, Brian L. Cousens
A preliminary study of older hot spring alteration in Sevenmile Hole, Grand Canyon of the Yellowstone River, Yellowstone Caldera, Wyoming
Erosion in the Grand Canyon of the Yellowstone River, Yellowstone Caldera (640 ka), Wyoming, has exposed a cross section of older hydrothermal alteration in the canyon walls. The altered outcrops of the post-collapse tuff of Sulphur Creek (480 ka) extend from the canyon rim to more than 300 m beneath it. The hydrothermal minerals are zoned, with an advanced argillic alteration consisting of an ass
Authors
Peter B. Larson, Allison Phillips, David John, Michael A. Cosca, Chad Pritchard, Allen K. Andersen, Jennifer Manion
Magmatic and tectonic evolution of the Caetano caldera, north-central Nevada: A tilted, mid-Tertiary eruptive center and source of the Caetano Tuff
The Caetano Tuff is a late Eocene, rhyolite ash-flow tuff that crops out within an ∼90-km-long, east-west–trending belt in north-central Nevada, previously interpreted as an elongate graben or “volcano-tectonic trough.” New field, petrographic, geochemical, and geochronologic data show that: (1) the east half of the “trough” is actually the Caetano caldera, formed by eruption of the Caetano Tuff a
Authors
David John, Christopher D. Henry, Joseph Colgan
Large-magnitude Miocene extension of the Eocene Caetano caldera, Shoshone and Toiyabe Ranges, Nevada
Because major mineral deposits in north-central Nevada predate significant Basin and Range extension, a detailed understanding of the timing and kinematics of extensional faulting is necessary to place these deposits in their original structural context. The complexity of pre-Cenozoic deformation in northern Nevada makes restoring Basin and Range faulting difficult without locating well-dated, reg
Authors
Joseph Colgan, David John, Christopher D. Henry, Robert J. Fleck
Science and Products
Filter Total Items: 60
Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada
Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada
//
//
This report presents petrographic and geochemical data for samples collected during investigations of Tertiary volcanism in the Bodie Hills of California and Nevada. Igneous rocks in the area are principally 15–6 Ma subduction-related volcanic rocks of the Bodie Hills volcanic
Authors
Edward A. du Bray, David John, Stephen E. Box, Peter G. Vikre, Robert J. Fleck, Brian L. Cousens
Miocene magmatism in the Bodie Hills volcanic field, California and Nevada: A long-lived eruptive center in the southern segment of the ancestral Cascades arc
The Middle to Late Miocene Bodie Hills volcanic field is a >700 km2, long-lived (∼9 Ma) but episodic eruptive center in the southern segment of the ancestral Cascades arc north of Mono Lake (California, U.S.). It consists of ∼20 major eruptive units, including 4 trachyandesite stratovolcanoes emplaced along the margins of the field, and numerous, more centrally located silicic trachyandesite to rh
Authors
David John, Edward A. du Bray, Richard J. Blakely, Robert J. Fleck, Peter G. Vikre, Stephen E. Box, Barry C. Moring
Epithermal gold-silver deposits of the Hauraki Goldfield, New Zealand: An introduction
No abstract available.
Authors
David John
Petrologic, tectonic, and metallogenic evolution of the Ancestral Cascades magmatic arc, Washington, Oregon, and northern California
Present-day High Cascades arc magmatism was preceded by ∼40 m.y. of nearly cospatial magmatism represented by the ancestral Cascades arc in Washington, Oregon, and northernmost California (United States). Time-space-composition relations for the ancestral Cascades arc have been synthesized from a recent compilation of more than 4000 geochemical analyses and associated age data. Neither the composi
Authors
Edward A. du Bray, David John
Episodic intrusion, internal differentiation, and hydrothermal alteration of the Miocene Tatoosh intrusive suite south of Mount Rainier, Washington
The Miocene Tatoosh intrusive suite south of Mount Rainier is composed of three broadly granodioritic plutons that are manifestations of ancestral Cascades arc magmatism. Tatoosh intrusive suite plutons have individually diagnostic characteristics, including texture, mineralogy, and geochemistry, and apparently lack internal contacts. New ion-microprobe U-Pb zircon ages indicate crystallization of
Authors
Edward A. du Bray, Charles R. Bacon, David John, Joseph L. Wooden, Frank K. Mazdab
Hydrothermal alteration of the Late Eocene Caetano ash-flow caldera, north-central Nevada: A field and ASTER remote sensing study
Geologic mapping and analysis of ASTER remote sensing data were used to define the effects of a large hydrothermal system in the 12–18 by 22 km Caetano caldera. The caldera formed at ~33.8Ma during eruption of >1100km3 of the rhyolitic Caetano Tuff that left a 1 km deep basin which was partly filled by a lake. Magma resurgence resulted in shallow(<1 km) emplacement of the Redrock Canyon granite po
Authors
David John, Barnaby W. Rockwell, Christopher D. Henry, Joseph Colgan
Porphyry copper deposit model
This report contains a revised descriptive model of porphyry copper deposits (PCDs), the world's largest source (about 60 percent) and resource (about 65 percent) of copper and a major source of molybdenum, gold and silver. Despite relatively low grades (average 0.44 percent copper in 2008), PCDs have significant economic and societal impacts due to their large size (commonly hundreds of millions
Authors
Robert A. Ayuso, Mark D. Barton, Richard J. Blakely, Robert J. Bodnar, John H. Dilles, Floyd Gray, Fred T. Graybeal, John L. Mars, Darcy McPhee, Robert R. Seal, Ryan D. Taylor, Peter G. Vikre
Mineral-resource assessment of northern Nye County, Nevada— A progress report
The U.S. Geological Survey (USGS), University of Nevada, Las Vegas (UNLV), and Nevada Bureau of Mines and Geology (NBMG), which is a part of the University of Nevada, Reno (UNR), have completed the first year of data collection and analysis in preparation for a new mineral- and energy-resource assessment of northern Nye County, Nevada. This report provides information about work completed before O
Authors
Steve Ludington, David John, John L. Muntean, Andrew D. Hanson, Stephen B. Castor, Christopher D. Henry, Niki Wintzer, Jean S. Cline, Adam C. Simon
Geochemical database for igneous rocks of the ancestral Cascades Arc— Southern segment, California and Nevada
Volcanic rocks that form the southern segment of the Cascades magmatic arc are an important manifestation of Cenozoic subduction and associated magmatism in western North America. Until recently, these rocks had been little studied and no systematic compilation of existing composition data had been assembled. This report is a compilation of all available chemical data for igneous rocks that consti
Authors
Edward A. du Bray, David John, Keith Putirka, Brian L. Cousens
A preliminary study of older hot spring alteration in Sevenmile Hole, Grand Canyon of the Yellowstone River, Yellowstone Caldera, Wyoming
Erosion in the Grand Canyon of the Yellowstone River, Yellowstone Caldera (640 ka), Wyoming, has exposed a cross section of older hydrothermal alteration in the canyon walls. The altered outcrops of the post-collapse tuff of Sulphur Creek (480 ka) extend from the canyon rim to more than 300 m beneath it. The hydrothermal minerals are zoned, with an advanced argillic alteration consisting of an ass
Authors
Peter B. Larson, Allison Phillips, David John, Michael A. Cosca, Chad Pritchard, Allen K. Andersen, Jennifer Manion
Magmatic and tectonic evolution of the Caetano caldera, north-central Nevada: A tilted, mid-Tertiary eruptive center and source of the Caetano Tuff
The Caetano Tuff is a late Eocene, rhyolite ash-flow tuff that crops out within an ∼90-km-long, east-west–trending belt in north-central Nevada, previously interpreted as an elongate graben or “volcano-tectonic trough.” New field, petrographic, geochemical, and geochronologic data show that: (1) the east half of the “trough” is actually the Caetano caldera, formed by eruption of the Caetano Tuff a
Authors
David John, Christopher D. Henry, Joseph Colgan
Large-magnitude Miocene extension of the Eocene Caetano caldera, Shoshone and Toiyabe Ranges, Nevada
Because major mineral deposits in north-central Nevada predate significant Basin and Range extension, a detailed understanding of the timing and kinematics of extensional faulting is necessary to place these deposits in their original structural context. The complexity of pre-Cenozoic deformation in northern Nevada makes restoring Basin and Range faulting difficult without locating well-dated, reg
Authors
Joseph Colgan, David John, Christopher D. Henry, Robert J. Fleck