Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2486
Application of a feedforward neural network in the search for kuroko deposits in the Hokuroku District, Japan Application of a feedforward neural network in the search for kuroko deposits in the Hokuroku District, Japan
A feedforward neural network with one hidden layer and five neurons was trained to recognize the distance to kuroko mineral deposits. Average amounts per hole of pyrite, sericite, and gypsum plus anhydrite as measured by X-rays in 69 drillholes were used to train the net. Drillholes near and between the Fukazawa, Furutobe, and Shakanai mines were used. The training data were selected...
Authors
Donald A. Singer, Ryoichi Kouda
The importance of geology in understanding and remediating environmental problems at Summitville The importance of geology in understanding and remediating environmental problems at Summitville
No abstract available.
Authors
Geoffrey S. Plumlee, John E. Gray, M. M. Roeber, Mark F. Coolbaugh, Marta J. Flohr, Gene Whitney
The role of serpentinite melanges in the unroofing of UHPM rocks: An example from the Western Alps of Italy: Chapter 6 The role of serpentinite melanges in the unroofing of UHPM rocks: An example from the Western Alps of Italy: Chapter 6
The ultrahigh pressure metamorphic rocks (UHPM) of the Dora-Maira continental massif are overlain by a stack of oceanic nappes. Metamorphic grade appears to increase downward but with marked discontinuities between each of the nappes, suggesting that section has been removed along the bounding faults. This apparent omission of section is greatest in the lowest oceanic unit where a...
Authors
M. Clark Blake, D.E. Moore, A. S. Jayko
Rapid extension recorded by cooling‐age patterns and brittle deformation, Naxos, Greece Rapid extension recorded by cooling‐age patterns and brittle deformation, Naxos, Greece
The metamorphic core complex exposed as the island of Naxos in the Aegean Sea records an unusually complete sequence of structures developed as a result of continental extension. The structures formed during Miocene rise and cooling from ductile, upper amphibolite facies and anatectic conditions to brittle near‐surface conditions beneath the Naxos detachment fault. Top‐to‐the‐north...
Authors
B.E. John, Keith A. Howard
Sources of the Early Cretaceous plutons in the Turtle and West Riverside Mountains, California Sources of the Early Cretaceous plutons in the Turtle and West Riverside Mountains, California
Ages and initial isotopic ratios of Early Cretaceous (˜100 Ma) plutons of the Cordilleran Interior in the southern Turtle and West Riverside mountains distinguish them from Late Cretaceous plutons in surrounding ranges in the eastern Mojave Desert. Furthermore, the studied plutons have isotopic and geochemical characteristics more similar to plutons of Cretaceous age in the coastal...
Authors
C. M. Allen, J. L. Wooden, Keith A. Howard, D.A. Foster, R. M. Tosdal
Geochemical processes controlling acid-drainage generation and cyanide degradation at Summitville Geochemical processes controlling acid-drainage generation and cyanide degradation at Summitville
No abstract available.
Authors
Geoffrey S. Plumlee, Kathleen S. Smith, Elwin L. Mosier, Walter H. Ficklin, Maria R. Montour, Paul Briggs, Allen L. Meier
The generation of oceanic rhyolites by crystal fractionation: the basalt-rhyolite association at Volcán Alcedo, Galápagos archipelago The generation of oceanic rhyolites by crystal fractionation: the basalt-rhyolite association at Volcán Alcedo, Galápagos archipelago
Alcedo volcano is one of six shield volcanoes on Isabela Island in the western Galápagos Islands. Although Alcedo is dominantiy basaltic, it is unusual in that it also has erupted ∼1 km3 of rhyolite. The rhyolitic phase marked a 10-fold decrease in the mass-eruption rate of the volcano, and the volcano has returned to erupting basalt. The basalts are tholeiitic and range from strongly to...
Authors
Dennis Geist, Keith A. Howard, Peter Larson
Hot-side-up aureole in southwest Yukon and limits on terrane assembly of the northern Canadian Cordillera: Comment and Reply Hot-side-up aureole in southwest Yukon and limits on terrane assembly of the northern Canadian Cordillera: Comment and Reply
No abstract available.
Authors
V. L. Hansen, D.H. Oliver, Cynthia Dusel-Bacon, Stephen T. Johnston, Philippe Erdmer
Latest Quaternary foraminifers and sediment transport in Pervenets Canyon, Bering Sea Latest Quaternary foraminifers and sediment transport in Pervenets Canyon, Bering Sea
A combination of microfossil and sediment analysis has been used in an attempt to understand oceanographic processes and the late Quaternary history of the Pervenets Canyon region. The primary sedimentation process in Pervenets Canyon is downslope transport. Near the shelfbreak, there is evidence of turbidite and debris-flow activity, but at the distal end of the upper canyon and on the
Authors
Scott W. Starratt
The geochemical cycling of stable Pb, 210Pb, and 210Po in seasonally anoxic Lake Sammamish, Washington, USA The geochemical cycling of stable Pb, 210Pb, and 210Po in seasonally anoxic Lake Sammamish, Washington, USA
The geochemical processes controlling the behavior of stable Pb, 210Pb, and 210po in seasonally anoxic Lake Sammamish, Washington were identified from water column distributions and box model calculations. Total (sum of dissolved and particulate) inventories of stable Pb, 210Pb, and 210Po increased in the whole lake during the latter part of the oxic stage of the lake and were attributed...
Authors
Laurie S. Balistrieri, James Murray, Barbara Paul
A teacher's guide to the San Francisco Bay area geophysics maps (U.S. Geological Survey GP-1006 and GP-1007) A teacher's guide to the San Francisco Bay area geophysics maps (U.S. Geological Survey GP-1006 and GP-1007)
No abstract available.
Authors
V.E. Langenheim, L. C. Gordon