Miocene volcanic rocks, undivided

In Western Utah: Quichapa Group and other volcanic rocks (Tmb,Tmr,Tma). In Central Utah: Silver Shield Latite (17 my) and Pinyon Creek Conglomerate.
State Utah
Name Miocene volcanic rocks, undivided
Geologic age Late Oligocene to Middle Miocene
Lithologic constituents
Igneous > Volcanic > Felsic-volcanic (Pyroclastic, Flow, Dome)
Igneous > Volcanic > Mafic-volcanic (Flow, Volcaniclastic)
Sedimentary > Clastic > Conglomerate (Bed)
Comments This unit mostly in Richfield 2 deg sheet. In the Delta sheet, includes the Topaz Mountain Rhyolite; also many local units
Stratigraphic units Topaz Mountain Rhyolite, Joe Lott Tuff, Mount Belknap Volcanics, Osiris Tuff, Mount Dutton Formation

Hintze, L.F., 1980, Geologic map of Utah: Utah Geological and Mineral Survey, scale 1:500,000.

Hintze, L.F., 1988, Geologic History of Utah: Brigham Young University Geology Studies Special Publication 7, 202 p.

Stevens, T.A., Morris, H.T., and Rowley, P.D., 1990, Geologic map of the Richfield 1øx2ø quadrangle, west-central Utah: U.S. Geological Survey Map I-1901, scale 1:250,000.


Lindsey, D.A., 1979, Geologic map and cross sections of Tertiary rocks in the Thomas Range and northern Drum Mountains, Juab County, Utah: Miscellaneous Investigations Series Report I- 1176, scale 1:62,500.

Shubat, M.A., Felger, T.J., and King, J.K., 1999, Geologic map of the Keg Mountain Ranch quadrangle, Juab County, Utah: Utah Geological Survey Miscellaneous Publication 99-5, 22 p, scale 1:24,000

NGMDB product
Counties Beaver - Garfield - Iron - Juab - Millard - Piute - Salt Lake - Sevier - Tooele - Utah - Washington - Wayne