Arikaree formation (MTTa;0)

State	Montana
Name	Arikaree formation
Geologic age	Phanerozoic \| Cenozoic \| Tertiary
Original map label	Ta
Primary rock type	sandstone
Secondary rock type	tuff
Other rock types	conglomerate
Lithologic constituents	Major Sedimentary > Clastic > Sandstone (Bed) Minor Sedimentary > Clastic > Conglomerate (Bed) Igneous > Volcanic (Pyroclastic, air fall)
Map references	Ross, P.R., Andrews, D.A., and Witkind, I.J., 1955, Geologic map of Montana: U.S. Geological Survey, 2 sheets, scale 1:500,000.
Unit references	Denson, N.M., Gibson, M.L. and Sims, G.L., 1992, Geologic and structure map of the north half of the Powder River basin, southeastern Montana and northeastern Wyoming: U.S. Geological Survey Miscellaneous Investigations Series Map I-2281-A, 1 [http://pubs.er.usgs.gov/publication/i2281A] Denson, N.M., and Gill, J.R., 1965, Uranium-bearing lignite and carbonaceous shale in the southwestern part of the Williston Basin--A regional study: U.S. Geological Survey Professional Paper 463, 75 p., 19 plates. [http://pubs.er.usgs.gov/publication/pp463] Denson, N.M., Macke, D.L. and Schumann, R.R., 1990, Geologic map and distribution of heavy minerals in Tertiary rocks of the Sheridan 30' x 60' quadrangle, Wyoming and Montana: U.S. Geological Survey Miscellaneous Investigations Series Map I- [http://pubs.er.usgs.gov/publication/i2020]
Geographic coverage	Carter