Ryan D Taylor
Ryan Taylor is a Research Geologist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 28
The Chahnaly low sulfidation epithermal gold deposit, western Makran volcanic arc, southeastern Iran
The Chahnaly low-sulfidation epithermal Au deposit and nearby Au prospects are located northwest of the intermittently active Bazman stratovolcano on the western end of the Makran volcanic arc, which formed as the result of subduction of the remnant Neo-Tethyan oceanic crust beneath the Lut block. The arc hosts the Siah Jangal epithermal and Kharestan porphyry prospects, near Taftan volcano, as we
Authors
Ali Sholeh, Ebrahim Rastad, David L. Huston, J. Bruce Gemmell, Ryan D. Taylor
Paleozoic magmatism and porphyry Cu-mineralization in an evolving tectonic setting in the North Qilian Orogenic Belt, NW China
The NWW-striking North Qilian Orogenic Belt records the Paleozoic accretion–collision processes in NW China, and hosts Paleozoic Cu–Pb–Zn mineralization that was temporally and spatially related to the closure of the Paleo Qilian-Qinling Ocean. The Wangdian Cu deposit is located in the eastern part of the North Qilian Orogenic Belt, NW China. Copper mineralization is spatially associated with an a
Authors
Kun-Feng Qiu, Jun Deng, Ryan D. Taylor, Kai-Rui Song, Yao-Hui Song, Quan-Zhong Li, Richard J. Goldfarb
By-products of porphyry copper and molybdenum deposits
Porphyry Cu and porphyry Mo deposits are large to giant deposits ranging up to >20 and 1.6 Gt of ore, respectively, that supply about 60 and 95% of the world’s copper and molybdenum, as well as significant amounts of gold and silver. These deposits form from hydrothermal systems that affect 10s to >100 km3 of the upper crust and result in enormous mass redistribution and potential concentration of
Authors
David John, Ryan D. Taylor
Hydrogeochemical exploration: a reconnaissance study on northeastern Seward Peninsula, Alaska
A reconnaissance hydrogeochemical study employing high-resolution/high-sensitivity inductively coupled plasma mass spectrometry analysis of stream and seep water samples (n= 171) was conducted in an area of limited bedrock exposure on the northeastern Seward Peninsula, Alaska. Sampling was focused in drainages around four main areas—at the Anugi Pb-Zn-Ag occurrence and in streams upstream of histo
Authors
Garth E. Graham, Ryan D. Taylor, Steve Buckley
Application of U-Th-Pb phosphate geochronology to young orogenic gold deposits: New age constraints on the formation of the Grass Valley gold district, Sierra Foothills province, California
The Grass Valley orogenic gold district in the Sierra Nevada foothills province, central California, the largest historic gold producer of the North American Cordillera, comprises both steeply dipping east-west (E-W) veins located along lithologic contacts in accreted ca. 300 and 200 Ma oceanic rocks and shallowly dipping north-south (N-S) veins hosted by the Grass Valley granodiorite; the latter
Authors
Ryan D. Taylor, Richard J. Goldfarb, Thomas Monecke, Ian R. Fletcher, Michael A. Cosca, Nigel M. Kelly
Targeting Cu–Au and Mo resources using multi-media exploration geochemistry: An example from Tyonek Quadrangle, Alaska Range, Alaska
Regional stream and pond sediment, panned concentrate, and water sampling at and around known mineral occurrences in the Tyonek quadrangle, Alaska Range, Alaska were undertaken to determine geochemical signatures in the different media. For sediment samples, two different size fractions (− 80 mesh and − 230 mesh) were analyzed. Elevated concentrations (mostly ~ 2 × median) of elements such as As,
Authors
Garth E. Graham, Ryan D. Taylor, Gregory K. Lee, Dick Tripp
Timing of ore-related magmatism in the western Alaska Range, southwestern Alaska
This report presents isotopic age data from mineralized granitic plutons in an area of the Alaska Range located approximately 200 kilometers to the west-northwest of Anchorage in southwestern Alaska. Uranium-lead isotopic data and trace element concentrations of zircons were determined for 12 samples encompassing eight plutonic bodies ranging in age from approximately 76 to 57.4 millions of years
Authors
Ryan D. Taylor, Garth E. Graham, Eric D. Anderson, David Selby
Phanerozoic continental growth and gold metallogeny of Asia
The Asian continent formed during the past 800 m.y. during late Neoproterozoic through Jurassic closure of the Tethyan ocean basins, followed by late Mesozoic circum-Pacific and Cenozoic Himalayan orogenies. The oldest gold deposits in Asia reflect accretionary events along the margins of the Siberia, Kazakhstan, North China, Tarim–Karakum, South China, and Indochina Precambrian blocks while they
Authors
Richard J. Goldfarb, Ryan D. Taylor, Gregory S. Collins, Nicolay A. Goryachev, Omero Felipe Orlandini
Stratiform chromite deposit model
A new descriptive stratiform chromite deposit model was prepared which will provide a framework for understanding the characteristics of stratiform chromite deposits worldwide. Previous stratiform chromite deposit models developed by the U.S. Geological Survey (USGS) have been referred to as Bushveld chromium, because the Bushveld Complex in South Africa is the only stratified, mafic-ultramafic in
Authors
Ruth F. Schulte, Ryan D. Taylor, Nadine M. Piatak, Robert R. Seal
Arc-related porphyry molybdenum deposit model
This report provides a descriptive model for arc-related porphyry molybdenum deposits. Presented within are geological, geochemical, and mineralogical characteristics that differentiate this deposit type from porphyry copper and alkali-feldspar rhyolite-granite porphyry molybdenum deposits. The U.S. Geological Survey's effort to update existing mineral deposit models spurred this research, which i
Authors
Ryan D. Taylor, Jane M. Hammarstrom, Nadine M. Piatak, Robert R. Seal
Stratiform chromite deposit model
Stratiform chromite deposits are of great economic importance, yet their origin and evolution remain highly debated. Layered igneous intrusions such as the Bushveld, Great Dyke, Kemi, and Stillwater Complexes, provide opportunities for studying magmatic differentiation processes and assimilation within the crust, as well as related ore-deposit formation. Chromite-rich seams within layered intrusio
Authors
Ruth F. Schulte, Ryan D. Taylor, Nadine M. Piatak, Robert R. Seal
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
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Filter Total Items: 28
The Chahnaly low sulfidation epithermal gold deposit, western Makran volcanic arc, southeastern Iran
The Chahnaly low-sulfidation epithermal Au deposit and nearby Au prospects are located northwest of the intermittently active Bazman stratovolcano on the western end of the Makran volcanic arc, which formed as the result of subduction of the remnant Neo-Tethyan oceanic crust beneath the Lut block. The arc hosts the Siah Jangal epithermal and Kharestan porphyry prospects, near Taftan volcano, as weAuthorsAli Sholeh, Ebrahim Rastad, David L. Huston, J. Bruce Gemmell, Ryan D. TaylorPaleozoic magmatism and porphyry Cu-mineralization in an evolving tectonic setting in the North Qilian Orogenic Belt, NW China
The NWW-striking North Qilian Orogenic Belt records the Paleozoic accretion–collision processes in NW China, and hosts Paleozoic Cu–Pb–Zn mineralization that was temporally and spatially related to the closure of the Paleo Qilian-Qinling Ocean. The Wangdian Cu deposit is located in the eastern part of the North Qilian Orogenic Belt, NW China. Copper mineralization is spatially associated with an aAuthorsKun-Feng Qiu, Jun Deng, Ryan D. Taylor, Kai-Rui Song, Yao-Hui Song, Quan-Zhong Li, Richard J. GoldfarbBy-products of porphyry copper and molybdenum deposits
Porphyry Cu and porphyry Mo deposits are large to giant deposits ranging up to >20 and 1.6 Gt of ore, respectively, that supply about 60 and 95% of the world’s copper and molybdenum, as well as significant amounts of gold and silver. These deposits form from hydrothermal systems that affect 10s to >100 km3 of the upper crust and result in enormous mass redistribution and potential concentration ofAuthorsDavid John, Ryan D. TaylorHydrogeochemical exploration: a reconnaissance study on northeastern Seward Peninsula, Alaska
A reconnaissance hydrogeochemical study employing high-resolution/high-sensitivity inductively coupled plasma mass spectrometry analysis of stream and seep water samples (n= 171) was conducted in an area of limited bedrock exposure on the northeastern Seward Peninsula, Alaska. Sampling was focused in drainages around four main areas—at the Anugi Pb-Zn-Ag occurrence and in streams upstream of histoAuthorsGarth E. Graham, Ryan D. Taylor, Steve BuckleyApplication of U-Th-Pb phosphate geochronology to young orogenic gold deposits: New age constraints on the formation of the Grass Valley gold district, Sierra Foothills province, California
The Grass Valley orogenic gold district in the Sierra Nevada foothills province, central California, the largest historic gold producer of the North American Cordillera, comprises both steeply dipping east-west (E-W) veins located along lithologic contacts in accreted ca. 300 and 200 Ma oceanic rocks and shallowly dipping north-south (N-S) veins hosted by the Grass Valley granodiorite; the latterAuthorsRyan D. Taylor, Richard J. Goldfarb, Thomas Monecke, Ian R. Fletcher, Michael A. Cosca, Nigel M. KellyTargeting Cu–Au and Mo resources using multi-media exploration geochemistry: An example from Tyonek Quadrangle, Alaska Range, Alaska
Regional stream and pond sediment, panned concentrate, and water sampling at and around known mineral occurrences in the Tyonek quadrangle, Alaska Range, Alaska were undertaken to determine geochemical signatures in the different media. For sediment samples, two different size fractions (− 80 mesh and − 230 mesh) were analyzed. Elevated concentrations (mostly ~ 2 × median) of elements such as As,AuthorsGarth E. Graham, Ryan D. Taylor, Gregory K. Lee, Dick TrippTiming of ore-related magmatism in the western Alaska Range, southwestern Alaska
This report presents isotopic age data from mineralized granitic plutons in an area of the Alaska Range located approximately 200 kilometers to the west-northwest of Anchorage in southwestern Alaska. Uranium-lead isotopic data and trace element concentrations of zircons were determined for 12 samples encompassing eight plutonic bodies ranging in age from approximately 76 to 57.4 millions of yearsAuthorsRyan D. Taylor, Garth E. Graham, Eric D. Anderson, David SelbyPhanerozoic continental growth and gold metallogeny of Asia
The Asian continent formed during the past 800 m.y. during late Neoproterozoic through Jurassic closure of the Tethyan ocean basins, followed by late Mesozoic circum-Pacific and Cenozoic Himalayan orogenies. The oldest gold deposits in Asia reflect accretionary events along the margins of the Siberia, Kazakhstan, North China, Tarim–Karakum, South China, and Indochina Precambrian blocks while theyAuthorsRichard J. Goldfarb, Ryan D. Taylor, Gregory S. Collins, Nicolay A. Goryachev, Omero Felipe OrlandiniStratiform chromite deposit model
A new descriptive stratiform chromite deposit model was prepared which will provide a framework for understanding the characteristics of stratiform chromite deposits worldwide. Previous stratiform chromite deposit models developed by the U.S. Geological Survey (USGS) have been referred to as Bushveld chromium, because the Bushveld Complex in South Africa is the only stratified, mafic-ultramafic inAuthorsRuth F. Schulte, Ryan D. Taylor, Nadine M. Piatak, Robert R. SealArc-related porphyry molybdenum deposit model
This report provides a descriptive model for arc-related porphyry molybdenum deposits. Presented within are geological, geochemical, and mineralogical characteristics that differentiate this deposit type from porphyry copper and alkali-feldspar rhyolite-granite porphyry molybdenum deposits. The U.S. Geological Survey's effort to update existing mineral deposit models spurred this research, which iAuthorsRyan D. Taylor, Jane M. Hammarstrom, Nadine M. Piatak, Robert R. SealStratiform chromite deposit model
Stratiform chromite deposits are of great economic importance, yet their origin and evolution remain highly debated. Layered igneous intrusions such as the Bushveld, Great Dyke, Kemi, and Stillwater Complexes, provide opportunities for studying magmatic differentiation processes and assimilation within the crust, as well as related ore-deposit formation. Chromite-rich seams within layered intrusioAuthorsRuth F. Schulte, Ryan D. Taylor, Nadine M. Piatak, Robert R. SealPorphyry 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 millionsAuthorsRobert 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 - News