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Escondido Creek Leucogranodiorite
Field Collector: Esper Signius Larsen Jr.
Place Collected:Probably near Escondido, San Luis Rey Quadrangle, Southern California
Object number: ROC21683
DescriptionPlutonic medium-grained (1-5 mm) igneous rock. Mostly white with some black flecks on a fresh surface and very light grey on a weathered surface. Consists of white plagioclase 50% (1 mm - 1 cm), grey quartz 35% (1 - 5 mm), light brown K-feldspar 10% (1-5 mm), black biotite 3 % (1-4 mm), and black hornblende 2 % (2 mm-1 cm). According to Larsen (1948) mineral modes are 45% plagioclase, 36% quartz, 10% microperthite, 3% biotite, 2% each of muscovite, epidote, and horblende, and 1% Fe-ore.
In Collection(s)