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

January 1, 1978

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 brief polarity event occurred at this time, as suggested by published studies of some marine sedimentary cores and magnetic anomalies. This new event is herein named the “Cobb Mountain normal polarity event.”

Publication Year 1978
Title Geomagnetic polarity event recorded at 1.1 m.y. B.P. on Cobb Mountain, Clear Lake volcanic field, California
DOI 10.1130/0091-7613(1978)6<653:GPERAM>2.0.CO;2
Authors Edward A. Mankinen, J.M. Donnelly, C. S. Grommé
Publication Type Article
Publication Subtype Journal Article
Series Title Geology
Index ID 70197174
Record Source USGS Publications Warehouse
USGS Organization Geology, Minerals, Energy, and Geophysics Science Center