Subaqueous pyroclastic ejecta of basaltic cinder cones (lower Pliocene? and Miocene?) (ORTps;0)

State	Oregon
Name	Subaqueous pyroclastic ejecta of basaltic cinder cones (lower Pliocene? and Miocene?)
Geologic age	Miocene to Early Pliocene
Original map label	Tps
Primary rock type	pyroclastic
Secondary rock type	mafic volcanic rock
Other rock types	intermediate volcanic rock
Lithologic constituents	Major Igneous > Volcanic > Mafic-volcanic > Basalt (Pyroclastic, cinder cone)Also contains material of intermediate composition (basaltic andesite and (or) andesite Incidental Sedimentary > Clastic > Mixed-clastic > Sandstone-Mudstone (Bed)
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. Walker, G.W., 1977, Geologic map of Oregon east of the 121st meridian: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-902, scale 1:500,000. [http://pubs.er.usgs.gov/publication/i902] Swisher, C.C., Ach, J.A., and Hart, W.K., 1990, Laser fusion 40Ar/39Ar dating of the type Steens Mountain Basalt, southeastern Oregon, and the age of the Steens aeromagnetic polarity transition [abs.]: EOS, Transactions of American Geophysical Union, v. 17, no. 43, p. 1,296. Ferns, M.L. and Cummings, M.L., 1992, Geology and mineral resources map of The Elbow quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-62, scale 1:24,000. Ferns, M.L., 1992, Preliminary geologic map of the Jordan Craters South quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Open-File Map O-92-09, scale 1:24,000. Beeson, J.H., Geology of the southern half of the Huntington quadrangle, Oregon: Eugene, University of Oregon, master's thesis, 77 p.
Geographic coverage	Baker - Crook - Harney - Klamath - Lake - Linn - Malheur