Mafic vent complexes

Intrusive plugs and dike swarms and related near-vent flows, breccias, cinders, and agglutinate of basaltic andesite, basalt, and andesite; commonly in the form of eroded piles of red, iron-stained thin flows, cinders, and agglutinate cut by mafic intrusions
State Oregon
Name Mafic vent complexes
Geologic age Miocene
Lithologic constituents
Major
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basaltic-andesite (Dike or sill, Stock or pipe)
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-basalt (Dike or sill, Stock or pipe)
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow, Volcaniclastic-volcanic breccia)
Minor
Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow, Volcaniclastic-volcanic breccia)
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Volcaniclastic-volcanic breccia)
Incidental
Igneous > Hypabyssal > Mafic-hypabyssal > Hypabyssal-andesite (Dike or sill, Stock or pipe)
References

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 - Jackson - Jefferson - Klamath - Lake - Lane - Linn - Marion - Wasco