Abstract

A previously undocumented belt of Upper Cretaceous, primary muscoviteand garnet-bearing granites is exposed within the Mesozoic batholith of the central and western Mojave Desert of California. This granite belt occurs more than 140 km west of the better known Cordilleran interior belt of primary muscovite-bearing granitoids, and the central and western Mojave granites are derived from much different sources, possibly Pelona-Orocopia-Rand schists or similar rocks. Anatexis of Pelona-Orocopia-Rand schists to produce these granites would require emplacement of the schists prior to the Late Cretaceous–early Tertiary, the most widely accepted time of schist emplacement. The granite belt may also correlate with similar rocks in the southernmost Sierra Nevada and eastern Salinia. The distinctive isotopic and petrologic character of the granite belt reflects differences in crustal structure between the Mojave–southern Sierra Nevada and the central Sierra Nevada portions of the Cretaceous continental margin batholith. Possible correlation of this belt with rocks in eastern Salinia also places further limits on the pre-early Tertiary position of Salinia.

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