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Temescal Quartz Latite Porphyry
Field Collector: Esper Signius Larsen Jr.
Place Collected:Near Corona, Corona Quadrangle, Southern California
Object number: ROC21711
DescriptionPorphyritic volcanic igneous rock with a dark grey groundmass and white phenocrysts. Mineral modes given by Larsen (1948) are 18% plagioclase phenocrysts and 5% quartz phenocrysts and 77% groundmass. The groundmass consists of mostly quartz and alkali feldspar with some nests of biotite and hornblende. Larsen called this rock a latite, but in modern nomenclature it would be called a dacite based on his chemical analysis.
In Collection(s)