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Quartzite, siltstone, conglomerate, and metavolcanic rocks; Late and Middle Proterozoic, undivided; Atlanta batholith roof pendants

Precambrian, high-grade metamorphic rock
State Idaho
Name Quartzite, siltstone, conglomerate, and metavolcanic rocks; Late and Middle Proterozoic, undivided; Atlanta batholith roof pendants
Geologic age Late and Middle Proterozoic, undivided
Comments ZYm includes Belt and Windermere strata, undivided, mostly as roof pendants and septa in the Atlanta lobe of the Idaho batholith (ID005).
Primary rock type quartzite
Secondary rock type meta-argillite
Other rock types metaconglomerate; schist; calc-silicate rock; marble; amphibolite; mafic metavolcanic rock; felsic metavolcanic rock
Lithologic constituents
Major
Metamorphic > Quartzite (Amphibolite)quartzite
Minor
Sedimentary > Clastic > Conglomerate (Bed)diamictic meta-conglomerate with metavolc and metased clasts
Metamorphic > Schist (Amphibolite)mica schist +/- sillimanite, staurolite
Metamorphic > Hornfels (Amphibolite)calc-silicate rock
Metamorphic > Marbledolomitic marble
Incidental
Metamorphic > Amphibolite (Amphibolite)
Metamorphic > Phyllite
Igneous > Volcanic > Mafic-volcanic
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.
Lund, Karen, Aleinikoff, J.N., Evans, K.V., and Fanning, C.M., 2003, SHRIMP U-Pb geochronology of Neoproterozoic Windermere Supergroup, central Idaho; implications for rifting of western Laurentia and synchroneity of Sturtian glacial deposits: Geological Society of America Bulletin, v. 115, no. 3, p. 349-372, 8 figures, 2 tables.
Evans, K.V. and Green, G.N., 2003, Geologic map of the Salmon National Forest and vicinity, east-central Idaho: U.S. Geological Survey Geological Investigations Series I-2765, scale 1:100,000 with pamphlet, 19 p.
Tysdal, R.G., 2000, Revision of Middle Proterozoic Yellowjacket Formation, central Idaho: U.S. Geological Survey Professional Paper 1601-A, p. A1-A13.
Counties Custer - Idaho - Lemhi - Valley