Belt Supergroup

Extremely large lumping of over 25+ formations. See individual unit descriptions. Belt Supergroup consists of: Missoula Group (Ym, Ymu, Yml), Piegan Group (Ypg, Yh), Ravalli Group (Yr, Ye, Ysp), and all the Lower Belt Formations (Ypu, Ypl, Yaw, Yla, Yg, Yn, Ynla, Ych, Yne).
State Montana
Name Belt Supergroup
Geologic age Middle Proterozoic
Lithologic constituents
Metamorphic > Metasedimentary > Metaclastic > Argillite
Metamorphic > Metasedimentary > Metaclastic > Metasiltstone
Metamorphic > Metasedimentary > Metaclastic > Quartzite
Sedimentary > Clastic > Conglomerate (Bed)
Sedimentary > Carbonate > Dolostone (Bed)
Sedimentary > Carbonate > Limestone (Bed)
Sedimentary > Clastic > Sandstone (Bed, Arkosic)
Sedimentary > Chemical > Evaporite > Salt (Bed)
Sedimentary > Chemical > Chert (Bed)

Vuke, S.M., Porter, K.W., Lonn, J.D., and Lopez, D.A., 2007, Geologic Map of Montana - Compact Disc: Montana Bureau of Mines and Geology: Geologic Map 62-C, 73 p., 2 sheets, scale 1:500,000. This map was digitized in 2012 as a result of a contract between the U.S. Geological Survey and the Montana Bureau of Mines and Geology.

NGMDB product
Counties Beaverhead - Granite - Missoula - Ravalli