Mafic vent complexes

Plugs, dikes, and related near-vent flows, breccia, cinders, and agglutinate of basalt, basaltic andesite, and andesite; commonly in the form of either little-modified lava cones or partly eroded piles of reddish, iron-stained thin flows and fragmental ejecta cut by mafic intrusions. May also include rocks of late Miocene(?) age
State Oregon
Name Mafic vent complexes
Geologic age Late Miocene to Pleistocene
Lithologic constituents
Major
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow, Dike or sill, Pyroclastic)
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Dike or sill, Pyroclastic)
Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow, Dike or sill, Pyroclastic)
Comments Unit is in a north-south zone along crest of Cascades and includes Newberry volcano.
References
NGMDB product
Counties Clackamas - Crook - Deschutes - Douglas - Hood River - Jackson - Jefferson - Klamath - Lane - Linn - Marion - Multnomah - Wasco