Mafic vent complexes (ORQTmv;0)

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	Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000. Waters, A.C., 1968, Reconnaissance geologic map of the Madras quadrangle, Jeffereson and Wasco Counties, Oregon" U.S. Geological Survey Miscellaneous Geological Investigations Map I-555, scale 1;125,000. https://pubs.er.usgs.gov/publication/i555
NGMDB product	NGMDB product page for 16259
Counties	Clackamas - Crook - Deschutes - Douglas - Hood River - Jackson - Jefferson - Klamath - Lane - Linn - Marion - Multnomah - Wasco

Mafic vent complexes

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

Waters, A.C., 1968, Reconnaissance geologic map of the Madras quadrangle, Jeffereson and Wasco Counties, Oregon" U.S. Geological Survey Miscellaneous Geological Investigations Map I-555, scale 1;125,000.