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Granodiorite Associated with Bonsall
Field Collector: Esper Signius Larsen Jr.
Place Collected:Near Perris, CA Elisnore Quadrangle, Southern California
Object number: ROC21701
DescriptionPlutonic, coarse grained (> 5 mm) igneous rock that mostly light-grey on a fresh surface, with flecks of black minerals. Analyzed mineral modes by Larsen (1948) are 47% plagioclase, 30% quartz, 14% alkalic (K-feldspar), 5% biotite, 3% hornblende, , and 1% accessory minerals. The plagioclase is light grey and ≤ 2 cm across, quartz is light-grey and ≤ 1 cm, biotite is black and ≤ 2 mm, horblende is black and ~1 mm, and K-fledspar is indistinguishable in hand specimen.
In Collection(s)