Skip to main content
U.S. flag

An official website of the United States government

Isotopic ages of minerals from granitic rocks of the central Sierra Nevada and Inyo Mountains, California

July 26, 1965

Potassium-argon ages of biotite and hornblende from specimens of 17 granitic plutons in the central Sierra Nevada and the western Inyo Mountains, California, range from 69 to 183 m. y. The Mount Givens, Lamarck. and Round Valley Peak Granodiorites and related younger and more felsic quartz monzonites represent a pulse of magma emplaced in the general time interval of 80-90 million years ago, during Cretaceous time. Mineral ages of granitic rocks that flank these plutons on both the east and the west have been reduced during the emplacement of the Cretaceous intrusive rocks and are minimum ages for the time of crystallization. The ages of hornblende from the Tinemaha Granodiorite (150 to 180 m. y.) may approach crystallization dates. In conjunction with ages for other intrusive rocks in the Sierra Nevada and adjacent desert ranges they strongly suggest a magmatic episode during the Early Jurassic.

Publication Year 1965
Title Isotopic ages of minerals from granitic rocks of the central Sierra Nevada and Inyo Mountains, California
DOI 10.1130/0016-7606(1965)76[155:IAOMFG]2.0.CO;2
Authors R. W. Kistler, P. C. Bateman, W. W. Brannock
Publication Type Article
Publication Subtype Journal Article
Series Title GSA Bulletin
Index ID 70222381
Record Source USGS Publications Warehouse