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Rhyolite ignimbrites, basalt flows, andesitic flows and tuffs, mudstone, conglomerate, and limestone; Quaternary to Tertiary volcanics and sediments; east-central Idaho

Pliocene silicic welded tuff, ash, and flow rock; most common in southwestern Idaho.
State Idaho
Name Rhyolite ignimbrites, basalt flows, andesitic flows and tuffs, mudstone, conglomerate, and limestone; Quaternary to Tertiary volcanics and sediments; east-central Idaho
Geologic age Pliocene
Comments QTvs includes andesitic Medicine Lodge Volcanics of Oligocene age, Edie School Rhyolite of Pliocene age, and Snake River Basalt of Quaternary age, undivided.
Primary rock type rhyolite
Secondary rock type ash-flow tuff
Other rock types basalt; lava flow; andesite; tuff
Lithologic constituents
Major
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic, ash-flow)welded tuff of Edie School Rhyolite
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic, tuff)waterlain tuff of Edie School Rhyolite
Minor
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)basalt flows of Snake River Group
Incidental
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow)lava flows of Late Oligocene Medicine Lodge Volcanics
Igneous > Volcanic > Mafic-volcanic > Andesite (Pyroclastic, tuff)crystal tuffs of Late Oligocene Medicine Lodge Volcanics
Sedimentary > Clastic > Mixed-clastic > Sandstone-Mudstone (Bed)sandstone and shale in Early Miocene Medicine Lodge Beds
Sedimentary > Clastic > Conglomerate (Bed)conglomerate in Early Miocene Medicine Lodge Beds
Sedimentary > Carbonate > Limestone (Bed)limestone in Early Miocene Medicine Lodge Beds
Map references
Bond, J.G., Kauffman, J.D., Miller, D.A., and Venkatakrishnan, Ramesh, 1978, Geologic map of Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology, with contributions from U.S. Geological Survey, scale 1:500,000.
Unit references
Bond, J.G., Kauffman, J.D., Miller, D.A., and Venkatakrishnan, Ramesh, 1978, Geologic map of Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology, with contributions from U.S. Geological Survey, scale 1:500,000.
Rember, W.C., and Bennett, E.H., 1979, Geologic map of the Dubois quadrangle, Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology Map Series, Dubois 2o quadrangle, scale 1:250,000.
Scholten, R., Keenmon, K.A. and Kupsch, W.O., 1955, Geology of the Lima region, southwestern Montana and adjacent Idaho: Geological Society of America Bulletin, v. 66, no. 4, p. 345-404.
Counties Clark