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Publications

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

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Geomagnetic polarity event recorded at 1.1 m.y. B.P. on Cobb Mountain, Clear Lake volcanic field, California Geomagnetic polarity event recorded at 1.1 m.y. B.P. on Cobb Mountain, Clear Lake volcanic field, California

Paleomagnetic studies show that a normal polarity event within the Matuyama reversed polarity epoch is recorded by one of the volcanic units on Cobb Mountain in northern California. K-Ar age determinations show that this event has an age of 1.12 ± 0.02 m.y. and clearly preceded the Jaramillo normal polarity event. These data provide the first confirmation from a subaerial volcano that a...
Authors
Edward A. Mankinen, J.M. Donnelly, C. S. Grommé

Distribution and character of upper Mesozoic subduction complexes along the west coast of North America Distribution and character of upper Mesozoic subduction complexes along the west coast of North America

Structurally complex sequences of sedimentary, volcanic, and intrusive igneous rocks characterize a nearly continuous narrow band along the Pacific coast of North America from Baja California, Mexico to southern Alaska. They occur in two modes: (1) as complexly folded but coherent sequences of graywacke and argillite that locally exhibit blueschist-grade metamorphism, and (2) as melanges
Authors
D. L. Jones, M.C. Blake, E. H. Bailey, R. J. McLaughlin

Significance of Mesozoic radiolarians from the pre-Nevadan rocks of the southern Klamath Mountains, California Significance of Mesozoic radiolarians from the pre-Nevadan rocks of the southern Klamath Mountains, California

Ribbon cherts and siliceous tuffs of the North Fork and Rattlesnake Creek terranes of the Klamath Mountains yield Mesozoic radiolarians. Rocks of the North Fork terrane were previously considered to be of Paleozoic age and those of the Rattlesnake Creek to be of Paleozoic and Triassic age, on the basis of fossiliferous limestone bodies that are now considered to be exotic blocks. In both...
Authors
W. P. Irwin, D. L. Jones, E.A. Pessagno
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