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Jasper Seamount: seven million years of volcanism

Geology

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Abstract

Jasper Seamount is a young, mid-sized (690 km3) oceanic intraplate volcano located about 500 km west-southwest of San Diego, California. Reliable 40Ar/39Ar age data were obtained for several milligram-sized samples of 4 to 10 Ma plagioclase by using a defocused laser beam to clean the samples before fusion. Gee and Staudigel suggested that Jasper Seamount consists of a transitional to tholeiitic shield volcano formed by flank transitional series lavas, overlain by flank alkalic series lavas and summit alkalic series lavas. Twenty-nine individual 40Ar/39Ar laser fusion analyses on nine samples confirm the stratigraphy: 10.3-10.0 Ma for the flank transitional series, 8.7-7.5 Ma for the flank alkalic series, and 4.8-4.1 Ma for the summit alkalic series. The alkalinity of the lavas clearly increases with time, and there appear to be 1 to 3 m.y. hiatuses between each series. -from Authors

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Jasper Seamount: seven million years of volcanism
Series title:
Geology
Volume
19
Issue:
4
Year Published:
1991
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
364
Last page:
368
Number of Pages:
5