Intrusive basalt and andesite (Pleistocene, Pliocene, and Miocene) (ORQTib;0)

Sills, plugs and dikes of basaltic andesite, basalt, and andesite. In the Cascade Range most of these represent feeders, exposed by erosion, for flows and flow breccias of units Tba and Trb and a few are feeders for units QTba and QTa; in foothills of western Cascades includes several sins and dikes that may represent feeders for flows in unit Tu. May include some invasive flows. Includes a few dikes of hornblende and plagioclase porphyritic andesite, commonly altered, that probably were feeders for parts of unit Tu

State	Oregon
Name	Intrusive basalt and andesite (Pleistocene, Pliocene, and Miocene)
Geologic age	Miocene to Pleistocene
Original map label	QTib
Primary rock type	basalt
Secondary rock type	andesite
Other rock types
Lithologic constituents	Minor Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-andesite (Stock or pipe) Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basaltic-andesite (Stock or pipe) Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basalt (Stock or pipe) Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basaltic-andesite (Dike or sill) Incidental Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-andesite (Dike or sill) Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basalt (Dike or sill)
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.
Geographic coverage	Clackamas - Klamath