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Publications

Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center

Filter Total Items: 2494

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

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

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

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

Geologic map of the Hayward fault zone, Contra Costa, Alameda, and Santa Clara counties, California: A digital database Geologic map of the Hayward fault zone, Contra Costa, Alameda, and Santa Clara counties, California: A digital database

The Hayward is one of three major fault zones of the San Andreas system that have produced large historic earthquakes in the San Francisco Bay Area (the others being the San Andreas and Calaveras). Severe earthquakes were generated by this fault zone in 1836 and in 1868, and several large earthquakes have been recorded since 1868. The Hayward fault zone is considered to be the most...
Authors
R. W. Graymer, D. L. Jones, E. E. Brabb

Preliminary geologic map of the Oat Mountain 7.5' quadrangle, southern California: A digital database Preliminary geologic map of the Oat Mountain 7.5' quadrangle, southern California: A digital database

This database, identified as "Preliminary Geologic Map of the Oat Mountain 7.5' Quadrangle, southern California: A Digital Database," has been approved for release and publication by the Director of the USGS. Although this database has been reviewed and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. This database is...
Authors
R.F. Yerkes, Russell H. Campbell
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