David A John
David is a Scientist Emeritus with the Geology, Minerals, Energy, and Geophysics Science Center
Science and Products
Filter Total Items: 59
Episodic intrusion, internal differentiation, and hydrothermal alteration of the Miocene Tatoosh intrusive suite south of Mount Rainier, Washington 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...
Authors
Edward A. du Bray, Charles R. Bacon, David A. 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 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(
Authors
David A. John, Barnaby W. Rockwell, Christopher D. Henry, Joseph P. Colgan
Porphyry copper deposit model 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...
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 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...
Authors
Steve Ludington, David A. 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 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...
Authors
Edward A. du Bray, David A. 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 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...
Authors
Peter B. Larson, Allison Phillips, David A. John, Michael A. Cosca, Chad Pritchard, Allen K. Andersen, Jennifer Manion
Science and Products
Filter Total Items: 59
Episodic intrusion, internal differentiation, and hydrothermal alteration of the Miocene Tatoosh intrusive suite south of Mount Rainier, Washington 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...
Authors
Edward A. du Bray, Charles R. Bacon, David A. 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 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(
Authors
David A. John, Barnaby W. Rockwell, Christopher D. Henry, Joseph P. Colgan
Porphyry copper deposit model 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...
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 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...
Authors
Steve Ludington, David A. 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 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...
Authors
Edward A. du Bray, David A. 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 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...
Authors
Peter B. Larson, Allison Phillips, David A. John, Michael A. Cosca, Chad Pritchard, Allen K. Andersen, Jennifer Manion