Advanced Search
Woodson Mountain Granodiorite
Field Collector: Esper Signius Larsen Jr.
Place Collected:San Luis Rey Quadrangle, Southern California
Object number: ROC21694
DescriptionPlutonic medium-grained (1-5 mm) igneous rock. Almost white on a fresh surface and light grey to yellow on weathered surface. Consists of white plagioclase ~ 50 % (1-2 mm), grey quartz ~35 % (2-5 mm), pale pink K-spar ~10 % (~4 mm), black biotite ~3 % (1-3mm), and black hornblende ~ 2 % (1-4 mm). Honblende and biotite sometimes form clumps up to 1.5 cm in diameter. Visually estimated mineral modes, there may be more K-spar and less plagiocalse.
In Collection(s)