Andesite

Forms major stratovolcanoes dominantly of aphyric to porphyritic basaltic andesite and andesite; phenocrysts are principally pyroxene, olivine, plagioclase, and, rarely, hornblende. Locally includes dacite and minor basalt
State Oregon
Name Andesite
Geologic age Quaternary
Lithologic constituents
Major
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow)
Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow)
Incidental
Igneous > Volcanic > Felsic-volcanic > Dacite (Flow)
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Comments stratocones
References

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

NGMDB product
Counties Baker - Clackamas - Deschutes - Douglas - Hood River - Jackson - Jefferson - Klamath - Lane - Linn - Marion