Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2542
Isostatic residual gravity and crustal geology of the United States Isostatic residual gravity and crustal geology of the United States
A new isostatic residual gravity map of the conterminous United States presents continent-wide gravity data in a form that can be readily used, with geologic information and other geophysical data, in studies of the composition and structure of the continental crust. This map was produced from the gridded gravity data on which the recently released Gravity Anomaly Map of the United...
Authors
Robert C. Jachens, Robert W. Simpson, Richard J. Blakely, Richard W. Saltus
Evolution of the western part of the Coast plutonic–metamorphic complex, South-Eastern Alaska, USA: A summary Evolution of the western part of the Coast plutonic–metamorphic complex, South-Eastern Alaska, USA: A summary
The western Cordillera of North America extends for over 6000 km from the tip of Baja California to the Alaska Range. It includes a wide variety of metamorphic and plutonic terrains, but none is more spectacular scenically or geologically than the Coast plutonic-metamorphic complex (Brew & Ford 1984) of western Canada and south-eastern Alaska. This report briefly describes the evolution...
Authors
David A. Brew, A. B. Ford, G. R. Himmelberg
Quantitative mineral resource assessment of undiscovered mineral deposits for selected mineral deposit types in the Chugach National Forest, Alaska Quantitative mineral resource assessment of undiscovered mineral deposits for selected mineral deposit types in the Chugach National Forest, Alaska
No abstract available.
Authors
James D. Bliss
Paleomagnetism and tectonic rotation of the lower Miocene Peach Springs Tuff: Colorado Plateau, Arizona, to Barstow, California Paleomagnetism and tectonic rotation of the lower Miocene Peach Springs Tuff: Colorado Plateau, Arizona, to Barstow, California
We have determined remanent magnetization directions of the lower Miocene Peach Springs Tuff at 41 localities in western Arizona and southeastern California. An unusual northeast and shallow magnetization direction confirms the proposed geologic correlation of isolated outcrops of the tuff from the Colorado Plateau to Barstow, California, a distance of 350 km. The Peach Springs Tuff was...
Authors
Ray E. Wells, John W. Hillhouse
Borax in the supraglacial moraine of the Lewis Cliff, Buckley Island quadrangle--first Antarctic occurrence Borax in the supraglacial moraine of the Lewis Cliff, Buckley Island quadrangle--first Antarctic occurrence
During the 1987-1988 austral summer field season, membersof the south party of the antarctic search for meteorites south-ern team* working in the Lewis Cliff/Colbert Hills region dis-covered several areas of unusual mineralization within theLewis Cliff ice tongue and its associated moraine field (figure1). The Lewis Cliff ice tongue (84°15'S 161°25'E) is a meteorite-stranding surface of...
Authors
J. J. Fitzpatrick, D.R. Muhs
Average topography, isostatic residual gravity, and aeromagnetic maps of the Parkfield region, California Average topography, isostatic residual gravity, and aeromagnetic maps of the Parkfield region, California
No abstract available.
Authors
Robert W. Simpson, R.C. Jachens, Carl M. Wentworth
Uranium-series ages, faunal correlations and tectonic deformation of marine terraces within the Agua Blanca fault zone at Punta Banda, northern Baja California, Mexico Uranium-series ages, faunal correlations and tectonic deformation of marine terraces within the Agua Blanca fault zone at Punta Banda, northern Baja California, Mexico
No abstract available.
Authors
T. K. Rockwell, D.R. Muhs, G. L. Kennedy, M.E. Hatch, S.M. Wilson, R.E. Klinger
Oligocene and Miocene paleogeography of central California and displacement along the San Andreas fault Oligocene and Miocene paleogeography of central California and displacement along the San Andreas fault
Recently completed sedimentologic and petrologic studies of Oligocene and Miocene strata in the Temblor Range (San Joaquin basin) and Santa Cruz Mountains (La Honda basin) permit detailed reconstructions of paleogeography, as well as new estimates of displacement along the San Andreas fault. During the Oligocene and Miocene, the San Joaquin and La Honda basins were contiguous. The...
Authors
S.A. Graham, Richard G. Stanley, J. V. Bent, J. B. Carter
Mechanisms of Cenozoic tectonic rotation, Pacific Northwest Convergent Margin, U.S.A. Mechanisms of Cenozoic tectonic rotation, Pacific Northwest Convergent Margin, U.S.A.
Large clockwise rotations (15–80°) are characteristic of Cenozoic volcanic and sedimentary rocks along the convergent margin of the northwestern United States. Abundant paleomagnetic data from 62–12 m.y. old rocks in forearc, arc, and backarc regions show that rotation increases with age and with proximity to the coast. Paleomagnetic and structural studies both support dextral shear as a
Authors
Ray E. Wells
Correlation of Miocene flows of the Columbia River Basalt Group from the central Columbia River Plateau to the coast of Oregon and Washington Correlation of Miocene flows of the Columbia River Basalt Group from the central Columbia River Plateau to the coast of Oregon and Washington
Nearly twenty flows of the Columbia River Basalt Group (CRBG) can be paleomagnetically and chemically correlated westward as far as 500 km from the Columbia Plateau in Washington, through the Columbia Gorge, to the Coast Range of Oregon and Washington. In the Coast Range near Cathlamet, Washington, the CRBG flow stratigraphy includes 10 flows of Grande Ronde Basalt (1 low-MgO R2 flow, 6...
Authors
Ray E. Wells, R.W. Simpson, R. D. Bentley, Melvin H. Beeson, Margaret T. Mangan, Thomas L. Wright
Paleomagnetic study of the Eastern Klamath terrane, California, and implications for the tectonic history of the Klamath Mountains Province Paleomagnetic study of the Eastern Klamath terrane, California, and implications for the tectonic history of the Klamath Mountains Province
Paleomagnetic study of Permian through Jurassic volcanic and sedimentary strata of the Eastern Klamath terrane has shown the remanent magnetization of many of these rocks to be prefolding and most likely primary. Similarities in magnetic declinations recorded by coeval strata over a broad area are consistent with the hypothesis that the terrane, in general, has behaved as a single rigid...
Authors
Edward A. Mankinen, William P. Irwin, C. Sherman Gromme
The style of late Cenozoic deformation at the eastern front of the California Coast Ranges The style of late Cenozoic deformation at the eastern front of the California Coast Ranges
The 1983 Coalinga earthquake occurred at the eastern boundary of the California Coast Ranges in response to northeast directed thrusting. Such movements over the past 2 Ma have produced Coalinga anticline by folding above the blind eastern tip of the Coalinga thrust zone. The 600-km length of the Coast Ranges boundary shares a common structural setting that involves westward upturn of...
Authors
Carl M. Wentworth, Mark D. Zoback