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Publications

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

Filter Total Items: 2481

Correlation of metamorphosed Paleozoic strata of the southeastern Mojave Desert region, California and Arizona Correlation of metamorphosed Paleozoic strata of the southeastern Mojave Desert region, California and Arizona

Isolated outcrops of deformed, regionally metamorphosed Paleozoic strata are scattered within the southeastern Mojave Desert region of California and western Arizona. These strata unconformably overlie a basement of Proterozoic crystalline rocks and are overlain in turn by metamorphosed Mesozoic sedimentary rocks. The strata can be correlated lithostratigraphically with the classic...
Authors
Paul Stone, Keith A. Howard, Warren Hamilton

New data on the age of Lepidocyclina in California New data on the age of Lepidocyclina in California

During the 1930's and early 1940's, controversy about the age of Lepidocyclina californica and faunas associated with it led to unreconcilable differences of opinion in the attempt to provide a standard stratigraphic framework for Cenozoic rocks of western North America. Two standards with significantly different series age assignments were provided, one based largelyon benthic...
Authors
E. E. Brabb, Kristen McDougall, R.Z. Poore

Introduction Introduction

Tectonic and Stratigraphic Studies in the Eastern Great Basin is compiled as a tribute to Max D. Crittenden, Jr., whose geologic leadership and exemplary studies in the eastern Great Basin region have stimulated significant scientific advances. Many of the authors in this volume conducted their studies with assistance from Max, and much of the foundation for these studies is his work on...
Authors
D. M. Miller, Keith A. Howard

Conodonts of the western Paleozoic and Triassic belt, Klamath Mountains, California and Oregon Conodonts of the western Paleozoic and Triassic belt, Klamath Mountains, California and Oregon

Conodonts were extracted from 32 samples of limestone and 5 samples of chert obtained from the Western Paleozoic and Triassic belt of the Klamath Mountains province. Triassic conodonts were found in 17 samples, and late Paleozoic conodonts in 7 samples. Conodonts of the remaining 13 samples cannot be dated more closely than early or middle Paleozoic through Triassic. The late Paleozoic...
Authors
William P. Irwin, Bruce R. Wardlaw, T.A. Kaplan

The ophiolitic North Fork terrane in the Salmon River region, central Klamath Mountains, California The ophiolitic North Fork terrane in the Salmon River region, central Klamath Mountains, California

The North Fork terrane is an assemblage of ophiolitic and other oceanic volcanic and sedimentary rocks that has been internally imbricated and folded. The ophiolitic rocks form a north-trending belt through the central part of the region and consist of a disrupted sequence of homogeneous gabbro, diabase, massive to pillowed basalt, and interleaved tectonitic harzburgite. U-Pb zircon age...
Authors
C.J. Ando, W. P. Irwin, D. L. Jones, J.B. Saleeby

Magnetic models of crystalline terrane; accounting for the effect of topography Magnetic models of crystalline terrane; accounting for the effect of topography

Igneous rocks commonly have large magnetic susceptibilities so that high topographic relief in crystalline terrane can produce significant anomalies in aeromagnetic surveys. Topographic anomalies are particularly significant in relatively undeformed volcanic terrane because young volcanic rocks generally have large natural remanent magnetizations as well as large susceptibilities. These...
Authors
Richard J. Blakely, V. J. Grauch

Intrusive rocks and plutonic belts of southeastern Alaska, U.S.A Intrusive rocks and plutonic belts of southeastern Alaska, U.S.A

About 30 percent of the 175,000-km2 area of southeastern Alaska is underlain by intrusive igneous rocks. Compilation of available information on the distribution, composition, and ages of these rocks indicates the presence of six major and six minor plutonic belts. From west to east, the major belts are: the Fairweather-Baranof belt of early to mid-Tertiary granodiorite; the Muir...
Authors
David A. Brew, Robert P. Morrell

Latest Oligocene through early middle Miocene diatom biostratigraphy of the eastern tropical Pacific Latest Oligocene through early middle Miocene diatom biostratigraphy of the eastern tropical Pacific

Study of DSDP Sites 71, 77, and 495 has allowed the development of a refined diatom biostratigraphy for the latest Oligocene through early middle Miocene of the eastern tropical Pacific which is well correlated to the low-latitude zonations for planktonic foraminifers, coccoliths, and radiolarians. Six zones and 7 subzones are proposed, and correlation with high-latitude diatoms...
Authors
John A. Barron
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