Flows and flow breccia in the High Cascade Province composed dominantly of aphyric to porphyritic basaltic andesite and andesite. Mostly represents remnants of moderately to deeply eroded stratovolcanoes. Phenocrysts are mostly plagioclase, olivine, clinopyroxene, and lesser hypersthene and hornblende
State Oregon
Name Andesite
Geologic age Pliocene to Pleistocene
Lithologic constituents
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow, Volcaniclastic-volcanic breccia)
Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow, Volcaniclastic-volcanic breccia)

Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000.

NGMDB product
Counties Clackamas - Douglas - Hood River - Klamath - Linn - Marion - Wasco