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Dolostone, arenite, conglomerate, and chert; Silurian to Middle Ordovician marine outer continental-shelf deposits; east-central Idaho

Silurian to Middle Ordovician marine carbonate-to-clastic strata of east-central Idaho.
State Idaho
Name Dolostone, arenite, conglomerate, and chert; Silurian to Middle Ordovician marine outer continental-shelf deposits; east-central Idaho
Geologic age Silurian to Middle Ordovician
Comments In the Dubois 1o x 2o quad, Saturday Mountain Fm and Laketown Dolomite comprise the SO unit. In the Idaho Falls 1o x 2o quad, Middle Ordovician Kinnikinic Quartzite also is included in the SO unit. Proportions of lithologies are estimated from information in Rupel and Lopez (1981). Churkin (1962) interprets Saturday Mtn. Fm as transitional between western eugeoclinal Phi Kappa Fm amd eastern miogeoclinal Fish Haven Dolomite. Similarly, the Laketown dolomite of central Idaho is transitional between western Trail Creek Fm and eastern miogeoclinal Laketown Dolomite. Kinnikinic Quartzite and Ramshorn Slate are transitional to miogeoclinal equivalents of the lower part of the Phi Kappa Fm.
Primary rock type dolostone (dolomite)
Secondary rock type arenite
Other rock types conglomerate; chert
Lithologic constituents
Major
Sedimentary > Carbonate > Dolostone (Lense)fossiliferous to cherty dolostone
Minor
Sedimentary > Clastic > Sandstone > Arenite (Bed)
Incidental
Sedimentary > Clastic > Conglomerate (Lense)
Sedimentary > Chemical > Chert (Lense)quartzite, pure, mostly medium-grained
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.
Rember, W.C., and Bennett, E.H., 1979, Geologic map of the Idaho Falls quadrangle, Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology, Geologic Map Series, Idaho Falls 2o quadrangle, scale 1:250,000.
Rupel, E.T. and Lopez, D.A., 1981, Geologic map of the Gilmore quadrangle, Lemhi and Custer Counties, Idaho: U.S. Geological Survey Geologic quadrangle Map GQ-1543, scale 1:62,500.
Counties Butte - Clark - Custer - Lemhi