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GMEG - Geophysics Unit of Menlo Park, CA- (GUMP)


Geophysics Unit of Menlo Park, CA (GUMP)

U.S. Geological Survey - Western Region - Geology and Geophysics

San Francisco Bay Area

INTRODUCTION--What do magnetics tell us?

Magnetic anomalies reflect variations in rock magnetizations. Often the magnetization of a rock is proportional to the amount of magnetite in the rock. Rocks in the San Francisco Bay area that are capable of producing measurable aeromagnetic anomalies are serpentinite, gabbro, and volcanic rocks.

Click here for the magnetism section of U.S. Geological Survey Open-File Report 95-479 (a teacher's guide to the San Francisco Bay Area Geophysics Maps).

Color magnetic maps

Color contour aeromagnetic map of the region. Red colors, magnetic highs; blue colors, magnetic lows; black lines, mapped faults.


See the article: Jachens, R.C., and Roberts, C.W., 1993, Aeromagnetic map of the San Francisco Bay area, California: U.S. Geological Survey Geophysical Investigations Map GP-1007. Available from the USGS--Information Services, Box 25286, Bldg. 810, Denver Federal Center, Denver, CO 80225 303 202-4210.

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