Reference 1517

Abstract

Mafic magmas supply heat and mass in the generation of silicic batholiths such as the Sierra Nevada batholith, but mafic rocks are uncommonly exposed and poorly studied. Field studies of mafic intrusive suites exposed along the eastern escarpment of the Sierra Nevada, between Big Pine and Independence, show that mafic magmatism is commonly expressed as thick suites of sills which intruded contemporaneously with silicic magma. The most striking of these suites is the Aberdeen intrusive suite which is composed of subhorizontal diorite sills with over 2 km of vertical exposure. Mafic/felsic interaction and magma mingling textures are observed from hand specimen scale to mountain-scale interdigitation of magma types. Isotopic study indicates that these chemically distinct magmas evolved from a similar source and that the mafic source of these magmas may not be depleted mantle as previously speculated, but an enriched lithospheric mantle

21 samples from this reference