Publications
Listed below are publication products directly associated with the Geology, Energy & Minerals Science Center:
Filter Total Items: 1261
Mineralogy, mineral chemistry, and paragenesis of gold, silver, and base-metal ores of the North Amethyst vein system, San Juan Mountains, Mineral County, Colorado Mineralogy, mineral chemistry, and paragenesis of gold, silver, and base-metal ores of the North Amethyst vein system, San Juan Mountains, Mineral County, Colorado
Gold-rich adularia-sericite-type mineralization occurs near the southern margin of the San Luis caldera, at the intersection of the Equity fault and the northern extension of the Amethyst fault system. Mineralized rock is confined primarily to steeply dipping structures in silicified rhyolite and dacite. Intense sericitic alteration occurs at higher levels in the vein system, and wall...
Authors
Nora K. Foley, Stanton W. Caddey, Craig B. Byington, David M. Vardiman
Pressure increases, the formation of chromite seams, and the development of the ultramafic series in the Stillwater Complex, Montana Pressure increases, the formation of chromite seams, and the development of the ultramafic series in the Stillwater Complex, Montana
This paper explores the hypothesis that chromite seams in the Stillwater Complex formed in response to periodic increases in total pressure in the chamber. Total pressure increased because of the positive δV of nucleation of CO2 bubbles in the melt and their subsequent rise through the magma chamber, during which the bubbles increased in volume by a factor of 4–6. By analogy with the...
Authors
Bruce R. Lipin
Mineral resource assessment of the Absaroka-Beartooth study area, Custer and Gallatin national forests, Montana Mineral resource assessment of the Absaroka-Beartooth study area, Custer and Gallatin national forests, Montana
No abstract available.
Authors
M. L. Zientek, J. E. Elliott
Geology of Keweenawan Supergroup Rocks near the Porcupine Mountains, Ontonagon and Gogebic Counties, Michigan Geology of Keweenawan Supergroup Rocks near the Porcupine Mountains, Ontonagon and Gogebic Counties, Michigan
This field trip examines the geology of rocks of the Keweenawan Supergroup (1 .1 Ga) and related intrusive rocks of the Midcontinent rift system (MRS) in the western part of the northern peninsula of Michigan. The combination of stops includes all formations of the Keweenawan Supergroup in this region. Examination of all described localities requires more than a single day and...
Authors
William F. Cannon, Suzanne W. Nicholson, Cheryl A. Hedgman, Laurel G. Woodruff, Klaus J. Schul
Revisions of stratigraphic nomenclature within the Keweenawan Supergroup of Northern Michigan. Geochemistry, petrography, and volcanology of rhyolites of the Portage Lake volcanics, Keweenaw Peninsula, Michigan Revisions of stratigraphic nomenclature within the Keweenawan Supergroup of Northern Michigan. Geochemistry, petrography, and volcanology of rhyolites of the Portage Lake volcanics, Keweenaw Peninsula, Michigan
No abstract available.
Authors
William F. Cannon, Suzanne W. Nicholson
Bedrock geology and mineral resources of the Knoxville 1° x 2° quadrangle, Tennessee, North Carolina, and South Carolina Bedrock geology and mineral resources of the Knoxville 1° x 2° quadrangle, Tennessee, North Carolina, and South Carolina
The Knoxville 1° x 2° quadrangle spans the Southern Blue Ridge physiographic province at its widest point from eastern Tennessee across western North Carolina to the northwest corner of South Carolina. The quadrangle also contains small parts of the Valley and Ridge province in Tennessee and the Piedmont province in North and South Carolina. Bedrock in the Valley and Ridge consists of
Authors
Gilpin R. Robinson, Frank G. Lesure, J. I. Marlowe, Nora K. Foley, S. H. Clark
Discussion of Blundy and Holland's (1990) "Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer" Discussion of Blundy and Holland's (1990) "Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer"
[No abstract available]
Authors
J. M. Hammarstrom, E-An Zen
Hydrothermal ore-forming processes in the light of studies in rock- buffered systems: I. Iron-copper-zinc-lead sulfide solubility relations Hydrothermal ore-forming processes in the light of studies in rock- buffered systems: I. Iron-copper-zinc-lead sulfide solubility relations
Experimental studies, using cold-seal and extraction vessel techniques, were conducted on Fe, Pb, Zn, and Cu sulfide solubilities in chloride solutions at temperatures from 300 degrees to 700 degrees C and pressures from 0.5 to 2 kbars. The solutions were buffered in pH by a quartz monzonite and the pure potassium feldspar-muscovite-quartz assemblage and in f (sub S 2 ) - f (sub O 2 )...
Authors
J.J. Hemley, G.L. Cygan, J.B. Fein, Robinson, W. M. d’Angelo
Sampling design for spatially distributed hydrogeologic and environmental processes Sampling design for spatially distributed hydrogeologic and environmental processes
A methodology for the design of sampling networks over space is proposed. The methodology is based on spatial random field representations of nonhomogeneous natural processes, and on optimal spatial estimation techniques. One of the most important results of random field theory for physical sciences is its rationalization of correlations in spatial variability of natural processes. This
Authors
G. Christakos, Ricardo A. Olea
Contributions to commodity geology research Contributions to commodity geology research
No abstract available.
Authors
DeYoung, Jane Marie Hammarstrom
USGS research on mineral resources, 1991; program and abstracts USGS research on mineral resources, 1991; program and abstracts
No abstract available.
Authors
Elizabeth E. Good, John F. Slack, Rama K. Kotra
Alternative natural gas contract and pricing structures and incentives of the LNG industry Alternative natural gas contract and pricing structures and incentives of the LNG industry
Gas conversion to liquefied gas (LNG) and transport by LNG tankers is one option for meeting expanding gas consumption and for gas traded internationally. This paper examines the impact of the traditional gas contract provisions of indefinite pricing, market out price ceilings, and take‐or‐pay requirements on the profitability of LNG projects in the context of markets characterized by...
Authors
Emil D. Attanasi