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Open-File Report 03-465

Preliminary Location and Age Database for Invertebrate Fossils Collected in the San Francisco Bay Region, California

Compiled by John M. Parker, William B. West, William T. Malmborg, and Earl E. Brabb

Thumbnail of and link to report PDF (40 kB)Introduction

Most geologic maps published for central California in the past century have been made without the benefit of microfossils. The age of Cretaceous and Tertiary rocks in the structurally complex sedimentary formations of the Coast Ranges is critical in determining stratigraphic succession and in determining whether the juxtapositon of similar appearing formations means that a fault is present. Since the 1930’s, at least, oil company geologists have used microfossils to assist them in geologic mapping and in determining the environments of deposition of sedimentary rocks. This information has been confidential, but in the past 20 years the attitude of petroleum companies about this information has changed, and much material is now available. We report here on approximately 4,700 samples, largely foraminifers, from surface localities in the San Francisco Bay region of California. The information contained here can be used to update geologic maps, to analyze the depth and temperature of ocean water covering parts of California during the Mesozoic and Cenozoic eras, and for solving other geologic problems.

First posted December 8, 2003

For additional information, contact:
Geology, Minerals, Energy, and Geophysics Science Center
U.S. Geological Survey
345 Middlefield Road, MS 901
Menlo Park, CA 94025-3591

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Suggested citation:

Compiled by Parker, John M., West, William B., Malmborg, William T., Brabb, Earl E., 2003, Preliminary Location and Age Database for Invertebrate Fossils Collected in the San Francisco Bay Region, California: U. S. Geological Survey Open-File Report 03-465, 5 pp.,

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