Basaltic andesite and basalt (Holocene? and Pleistocene)

Flows and flow breccia dominantly of basaltic andesite containing plagioclase, olivine, and pyroxene phenocrysts and olivine-bearing basalt representing part of the volcanic sequence of the High Cascade Range (Thayer, 1937). Unit mostly forms small shield volcanoes, gentle-sided lava cones, and, in places, intracanyon flows
State Oregon
Name Basaltic andesite and basalt (Holocene? and Pleistocene)
Geologic age Quaternary
Comments smaller cones and flows
Primary rock type basalt
Secondary rock type andesite
Other rock types
Lithologic constituents
Major
Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow)
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Map references
Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000.
Unit references
Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000.
Counties Clackamas - Deschutes - Douglas - Hood River - Jackson - Jefferson - Klamath - Lane - Linn - Marion - Wasco