Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2350
Fractal lognormal percentage assessment of porphyry copper resources
No abstract available.
Authors
R. A. Crovelli, S. B. Suslick, Donald A. Singer, R.H. Balay
World class base and precious metal deposits; a quantitative analysis
Over 62 percent of the 193,000 metric tons of gold discovered to date is located in four countries and more than 68 percent occurs in four types of mineral deposits. About 55 percent of the 1,740,000 metric tons of silver found is in four countries and 45 percent is in four types of deposits. Fifty-six percent of the 1.52 billion metric tons of discovered copper is from four countries and four typ
Authors
Donald A. Singer
Biostratigraphic constraints on formation and timing of accretion in a subduction complex: An example from the Franciscan Complex of Northern California
The determination of the total age coverage of pelagic bedded chert is particularly important in studies of ancient accretionary complexes because the time span represents the minimum travel time of an oceanic plate before accretion at an island arc or continental margin. The Yolla Bolly terrane of the Franciscan Complex consists of rare metabasalt overlain by bedded radiolarian chert which in tur
Authors
Y. Isozaki, M. Clark Blake
Paleozoic ophiolitic assemblages within the southern New England orogen of eastern Australia: Implications for growth of the Gondwana margin
Several ophiolitic assemblages occur in the southern New England orogen. The development of these rocks and their relations to the rest of the orogen have major implications for the tectonic evolution of eastern Gondwana. A major, narrow but elongate belt of Early Cambrian suprasubduction zone ophiolite crops out along and near the PeelManning Fault System and is juxtaposed against younger arc and
Authors
J.C. Aitchinson, M. Clark Blake, P.G. Flood, A. S. Jayko
A special issue on volcanic centers as targets for mineral exploration; preface
NEPTUNE or Pluto? Since the days of Hutton and Werner, every generation of economic geologists has addressed this question in a new light. Most papers in this special issue deal with the thin and leaky roof of Pluto's underworld. It allows hot emanations from Hades to leak out, only to be quenched and diluted by waters percolating down from Neptune's realm.
Mineralogy, paragenesis, and mineral zoning of the Bulldog Mountain vein system, Creede District, Colorado
The Bulldog Mountain vein system, Creede district, Colorado, is one of four major epithermal vein systems from which the bulk of the district's historical Ag-Pb-Zn-Cu production has come. Ores deposited along the vein system were discovered in 1965 and were mined from 1969 to 1985.Six temporally gradational mineralization stages have been identified along the Bulldog Mountain vein system, each wit
Authors
Geoffrey S. Plumlee, Pamela Heald Whitehouse-Veaux
Compositions, growth mechanisms, and temporal relations of hydrothermal sulfide‐sulfate‐silica chimneys at the northern Cleft segment, Juan de Fuca Ridge
Three active hydrothermal vents forming sulfide mounds and chimneys (Monolith, Fountain, and Pipe Organ) and more widely distributed inactive chimneys are spatially related to a system of discontinuous fissures and young sheet flow lavas at the northern Cleft segment, Juan de Fuca Ridge. The formation of zoned tubular Curich chimneys (type I) on the Monolith sulfide mound is related to focused flo
Authors
Randolph A. Koski, I. Jonasson, D. Kadko, Virginia K. Smith, Florence L. Wong
Preliminary geologic map of the Niles 7.5-minute Quadrangle, Alameda County, California
No abstract available.
Authors
R. W. Graymer, D. L. Jones, E. E. Brabb, E. J. Helley
Circum-North Pacific tectonostratigraphic terrane map
The companion tectonostratigraphic terrane and overlap assemblage of map the Circum-North Pacific presents a modern description of the major geologic and tectonic units of the region. The map illustrates both the onshore terranes and overlap volcanic assemblages of the region, and the major offshore geologic features. The map is the first collaborative compilation of the geology of the region at a
Authors
Warren J. Nokleberg, Leonid M. Parfenov, James W.H. Monger, Boris B. Baranov, Stanislav G. Byalobzhesky, Thomas K. Bundtzen, Tracey D. Feeney, Kazuya Fujita, Steven P. Gordey, Arthur Grantz, Alexander I. Khanchuk, Boris A. Natal'in, Lev M. Natapov, Ian O. Norton, William W. Patton, George Plafker, David W. Scholl, Sergei D. Sokolov, Gleb M. Sosunov, David B. Stone, Rowland W. Tabor, Nickolai V. Tsukanov, Tracy L. Vallier, Koji Wakita
Preliminary geologic map emphasizing bedrock formations in Contra Costa County, California: A digital database
No abstract available.
Authors
R. W. Graymer, David Lawrence Jones, Earl E. Brabb
Geologic studies in Alaska by the U.S. Geological Survey, 1993
This collection of 19 papers continues the annual series of U.S. Geological Survey reports on geologic investigations in Alaska. Contributions include 14 Articles and 5 shorter Geologic Notes that report results from all corners of the State.USGS activities in Alaska cover a broad spectrum of earth science topics, including the environment, hazards, resources, and geologic framework studies. Three
New uranium-series ages of the Waimanalo Limestone, Oahu, Hawaii: implications for sea level during the last interglacial period
The Waimanalo Formation (limestone) of Oahu has been correlated with the last interglacial period based on U-series dating of corals by T.-L. Ku and colleagues. The limestone consists of growth-position corals and overlying coral conglomerate. An apparent bimodal distribution of ages for the growth-position corals (mean age = 133 ka) and the overlying coral conglomerate (mean age = 119 ka) has bee
Authors
D.R. Muhs, B. J. Szabo