Edward A du Bray (Former Employee)
Science and Products
Filter Total Items: 16
Filter Total Items: 100
Composition, age, and petrogenesis of Late Cretaceous intrusive rocks in the central Big Belt Mountains, Broadwater and Meagher counties, Montana Composition, age, and petrogenesis of Late Cretaceous intrusive rocks in the central Big Belt Mountains, Broadwater and Meagher counties, Montana
Cretaceous intrusions hosted by the Proterozoic Newland Formation. The northern intrusion, centered on Boulder Baldy, consists of outer, intermediate, and core zones composed of aegirine-augite quartz monzonite, hornblende quartz monzodiorite, and biotite granodiorite, respectively. The southern intrusion, north of Mount Edith, is compositionally indistinguishable from the intermediate...
Authors
E. A. Du Bray, L.W. Snee
SHRIMP U-Pb and 40Ar/39Ar age constraints for relating plutonism and mineralization in the Boulder batholith region, Montana SHRIMP U-Pb and 40Ar/39Ar age constraints for relating plutonism and mineralization in the Boulder batholith region, Montana
The composite Boulder batholith, Montana, hosts a variety of mineral deposit types, including important silver-rich polymetallic quartz vein districts in the northern part of the batholith and the giant Butte porphyry copper-molybdenum pre-Main Stage system and crosscutting copper-rich Main Stage vein system in the southern part of the batholith. Previous dating studies have identified...
Authors
Karen Lund, John N. Aleinikoff, Michael J. Kunk, Daniel M. Unruh, G. D. Zeihen, W. C. Hodges, Edward A. du Bray, J. Michael O’Neill
Recrystallization and anatexis along the plutonic-volcanic contact of the Turkey Creek caldera, Arizona Recrystallization and anatexis along the plutonic-volcanic contact of the Turkey Creek caldera, Arizona
Unusual geologic and geochemical relations are preserved along the contact between intracaldera tuff and a resurgent intrusion within the 26.9 Ma Turkey Creek caldera of southeast Arizona. Thick intracaldera tuff is weakly argillically altered throughout, except in zones within several hundred meters of its contact with the resurgent intrusion, where the groundmass of the tuff has been...
Authors
du Bray, J.S. Pallister
Geology, age, and tectonic setting of the Cretaceous Sliderock Mountain Volcano, Montana Geology, age, and tectonic setting of the Cretaceous Sliderock Mountain Volcano, Montana
The Sliderock Mountain stratovolcano, part of the Upper Cretaceous continental magmatic arc in southwestern Montana, consists of volcaniclastic strata and basaltic andesite lava flows. An intrusive complex represents the volcano's solidified magma chamber. Compositional diversity within components of the volcano appears to reflect evolution via about 50 percent fractional crystallization...
Authors
E. A. Du Bray, Stephen S. Harlan
Mineral resource assessment; Custer and Gallatin national forests, Montana Mineral resource assessment; Custer and Gallatin national forests, Montana
No abstract available.
Authors
Jane Marie Hammarstrom, Anna B. Wilson, Bradley S. Van Gosen, Robert R. Carlson, Dolores M. Kulik, Gregory K. Lee, James E. Elliott, William J. Perry, Edward A. du Bray, Michael L. Zientek
The Eocene Big Timber stock, south-central Montana: Development of extensive compositional variation in an arc-related intrusion by side-wall crystallization and cumulate glomerocryst remixing The Eocene Big Timber stock, south-central Montana: Development of extensive compositional variation in an arc-related intrusion by side-wall crystallization and cumulate glomerocryst remixing
The Eocene Big Timber stock in the Crazy Mountains of south-central Montana is an elliptical, 8 by 13 km, compositionally and texturally diverse composite intrusion with a well-developed radial dike swarm. A sharp intrusive contact separates its two phases: the core of the intrusion is fine-grained quartz monzodiorite, and the volumetrically dominant remainder is composed of medium...
Authors
du Bray, S. S. Harlan
Area adjacent to the Turkey Creek caldera, Cochise County, Arizona— Analytic data and geologic sample catalog Area adjacent to the Turkey Creek caldera, Cochise County, Arizona— Analytic data and geologic sample catalog
No abstract available.
Authors
E. A. Du Bray, John S. Pallister
Complete analytical data for samples of the Big Timber Stock, Crazy Mountains, Montana Complete analytical data for samples of the Big Timber Stock, Crazy Mountains, Montana
No abstract available.
Authors
E. A. Du Bray
Geochemistry and petrology of Oligocene and Miocene ash-flow tuffs of the southeastern Great Basin, Nevada Geochemistry and petrology of Oligocene and Miocene ash-flow tuffs of the southeastern Great Basin, Nevada
The White River Narrows area of Southeast Nevada contains 18 regionally distributed middle Tertiary dacite to rhyolite ash-flow tuffs. Geochemical data provide an excellent opportunity to study stratigraphic and petrologic relations of these tuffs. Chemical data for each of the tuffs are distinctive and provide a significant addition to other data used to identify and correlate these...
Authors
Edward A. du Bray
Compositional characteristics of middle to upper Tertiary volcanic rocks of the Bolivian Altiplano Compositional characteristics of middle to upper Tertiary volcanic rocks of the Bolivian Altiplano
No abstract available.
Authors
E. A. Du Bray, S. D. Ludington, W. E. Brooks, B. M. Gamble, J.C. Ratte, D.H. Richter, Eduardo Soria-Escalante
Science and Products
Filter Total Items: 16
Filter Total Items: 100
Composition, age, and petrogenesis of Late Cretaceous intrusive rocks in the central Big Belt Mountains, Broadwater and Meagher counties, Montana Composition, age, and petrogenesis of Late Cretaceous intrusive rocks in the central Big Belt Mountains, Broadwater and Meagher counties, Montana
Cretaceous intrusions hosted by the Proterozoic Newland Formation. The northern intrusion, centered on Boulder Baldy, consists of outer, intermediate, and core zones composed of aegirine-augite quartz monzonite, hornblende quartz monzodiorite, and biotite granodiorite, respectively. The southern intrusion, north of Mount Edith, is compositionally indistinguishable from the intermediate...
Authors
E. A. Du Bray, L.W. Snee
SHRIMP U-Pb and 40Ar/39Ar age constraints for relating plutonism and mineralization in the Boulder batholith region, Montana SHRIMP U-Pb and 40Ar/39Ar age constraints for relating plutonism and mineralization in the Boulder batholith region, Montana
The composite Boulder batholith, Montana, hosts a variety of mineral deposit types, including important silver-rich polymetallic quartz vein districts in the northern part of the batholith and the giant Butte porphyry copper-molybdenum pre-Main Stage system and crosscutting copper-rich Main Stage vein system in the southern part of the batholith. Previous dating studies have identified...
Authors
Karen Lund, John N. Aleinikoff, Michael J. Kunk, Daniel M. Unruh, G. D. Zeihen, W. C. Hodges, Edward A. du Bray, J. Michael O’Neill
Recrystallization and anatexis along the plutonic-volcanic contact of the Turkey Creek caldera, Arizona Recrystallization and anatexis along the plutonic-volcanic contact of the Turkey Creek caldera, Arizona
Unusual geologic and geochemical relations are preserved along the contact between intracaldera tuff and a resurgent intrusion within the 26.9 Ma Turkey Creek caldera of southeast Arizona. Thick intracaldera tuff is weakly argillically altered throughout, except in zones within several hundred meters of its contact with the resurgent intrusion, where the groundmass of the tuff has been...
Authors
du Bray, J.S. Pallister
Geology, age, and tectonic setting of the Cretaceous Sliderock Mountain Volcano, Montana Geology, age, and tectonic setting of the Cretaceous Sliderock Mountain Volcano, Montana
The Sliderock Mountain stratovolcano, part of the Upper Cretaceous continental magmatic arc in southwestern Montana, consists of volcaniclastic strata and basaltic andesite lava flows. An intrusive complex represents the volcano's solidified magma chamber. Compositional diversity within components of the volcano appears to reflect evolution via about 50 percent fractional crystallization...
Authors
E. A. Du Bray, Stephen S. Harlan
Mineral resource assessment; Custer and Gallatin national forests, Montana Mineral resource assessment; Custer and Gallatin national forests, Montana
No abstract available.
Authors
Jane Marie Hammarstrom, Anna B. Wilson, Bradley S. Van Gosen, Robert R. Carlson, Dolores M. Kulik, Gregory K. Lee, James E. Elliott, William J. Perry, Edward A. du Bray, Michael L. Zientek
The Eocene Big Timber stock, south-central Montana: Development of extensive compositional variation in an arc-related intrusion by side-wall crystallization and cumulate glomerocryst remixing The Eocene Big Timber stock, south-central Montana: Development of extensive compositional variation in an arc-related intrusion by side-wall crystallization and cumulate glomerocryst remixing
The Eocene Big Timber stock in the Crazy Mountains of south-central Montana is an elliptical, 8 by 13 km, compositionally and texturally diverse composite intrusion with a well-developed radial dike swarm. A sharp intrusive contact separates its two phases: the core of the intrusion is fine-grained quartz monzodiorite, and the volumetrically dominant remainder is composed of medium...
Authors
du Bray, S. S. Harlan
Area adjacent to the Turkey Creek caldera, Cochise County, Arizona— Analytic data and geologic sample catalog Area adjacent to the Turkey Creek caldera, Cochise County, Arizona— Analytic data and geologic sample catalog
No abstract available.
Authors
E. A. Du Bray, John S. Pallister
Complete analytical data for samples of the Big Timber Stock, Crazy Mountains, Montana Complete analytical data for samples of the Big Timber Stock, Crazy Mountains, Montana
No abstract available.
Authors
E. A. Du Bray
Geochemistry and petrology of Oligocene and Miocene ash-flow tuffs of the southeastern Great Basin, Nevada Geochemistry and petrology of Oligocene and Miocene ash-flow tuffs of the southeastern Great Basin, Nevada
The White River Narrows area of Southeast Nevada contains 18 regionally distributed middle Tertiary dacite to rhyolite ash-flow tuffs. Geochemical data provide an excellent opportunity to study stratigraphic and petrologic relations of these tuffs. Chemical data for each of the tuffs are distinctive and provide a significant addition to other data used to identify and correlate these...
Authors
Edward A. du Bray
Compositional characteristics of middle to upper Tertiary volcanic rocks of the Bolivian Altiplano Compositional characteristics of middle to upper Tertiary volcanic rocks of the Bolivian Altiplano
No abstract available.
Authors
E. A. Du Bray, S. D. Ludington, W. E. Brooks, B. M. Gamble, J.C. Ratte, D.H. Richter, Eduardo Soria-Escalante