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Rhyolite ignimbrites, latite and basalt lava flows, late Eocene rhyolitic ignimbrite cauldron complex; east-central Idaho, northern Challis volcanic field

Eocene mixed silicic and basaltic volcanic ejecta, flows and reworked debris.
State Idaho
Name Rhyolite ignimbrites, latite and basalt lava flows, late Eocene rhyolitic ignimbrite cauldron complex; east-central Idaho, northern Challis volcanic field
Geologic age Eocene
Comments Tevf consists mostly of Sunnyside rhyolitic ash-flow tuff (46 Ma), which is underlain by lower latite tuff (50-46 Ma), and overlain by Dewey volcaniclastic sedimentary beds, and upper latite flows (43 Ma), in the Thunder Mountain cauldron complex, which consists of the Thunder Mountain caldera and surrounding Cougar Basin caldera (ID135, ID013). In the Salmon area, Kadletz Volcanics are upper latite and basalt flows of the Challis Volcanic Group (ID140). These are similar in composition and stratigraphic position to the upper latite flows of the Thunder Mtn. cauldron complex.
Primary rock type rhyolite
Secondary rock type latite
Other rock types ignimbrite; lava flow; mixed clastic/volcanic; basalt
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.
Hardyman, R.F., 1989, Eocene magmatism, Challis volcanic field, central Idaho: in 28th International Geological Congress Field Trip Series, Volcanism and Plutonism of western North America, Vol. 2, Washington D.C., American Geophysical Union, p. T337: 32-38.
Fisher, F.S., McIntyre, D.H., and Johnson, K.M., 1992, Geologic map of the Challis 1o x 2o quadrangle, Idaho: U.S. Geological Survey Miscellaneous Investigations Series Map I-1819, scale 1:250,000 with pamphlet, 39 p.
Lund, Karen, in press, Geology of the Payette National Forest, Valley, Idaho, Washington and Adams counties, Idaho: U.S. Geological Survey Professional Paper 1666, scale 1:100,000.
Rember, W.C. and Bennett, E.H., 1979, Geologic map of the Challis quadrangle, Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology, Geologic Map Series, Challis 2o quadrangle, scale 1:250,000.
Leonard, B.F., and Marvin, R.F., 1982, Temporal evolution of the Thunder Mountain caldera and related features, central Idaho: in Bonnichsen, Bill, and Breckenridge, R.M., eds., Cenozoic geology of Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology Bulletin 26, p. 23-41.
McIntyre, D.H., Ekren, E.B., and Hardyman, R.F., 1982, Stratigraphic and structural framework of the Challis Volcanics in the eastern half of the Challis 1o x 2o quadrangle, Idaho: in Bonnichsen, Bill, and Breckenridge, R.M., eds., Cenozoic geology of Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology Bulletin 26, p. 3-22
Counties Clearwater - Idaho - Valley