Potassium-argon ages of hornblende and biotite from granitic rocks in the central White-Inyo mountains of California indicate that the composite Inyo batholith was emplaced in Early to Middle Jurassic time (184–151 m.y.) and contains a small, possibly xenolithic, body of foliated granodiorite of Triassic age (213 m.y.). Two isolated plutons (Sage Hen Flat, 138–130 m.y. and Birch Creek, 80–77 m.y.) were emplaced in the metamorphic rocks west of the batholith in the Cretaceous. The range of K-Ar ages of intrusive rocks of the White-Inyo mountains is similar to that of the Sierra Nevada and supports the concept that the Inyo and Sierra batholiths are comagmatic.

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