Middle Tertiary sediment or sedimentary rock

Tuffaceous siltstone, sandstone, bentonitic mudstone, conglomerate, limestone, and equivalent sediment and ash beds. Local volcanic flows in southwestern Montana. Includes Renova Formation. Dominantly fluvial, floodplain, palustrine, lacustrine, debris flow, and eolian. Composite thickness for Tsu and Tsm exceeds 4,880 m (16,010 ft). Includes Anaconda Formation: Light gray, reddish tan, or brownish red, coarse breccia that laterally grades to conglomerate, sandstone, and siltstone. Locally intertongues with Lowland Creek Volcanics. Derived from overlying unmetamorphosed plate of metamorphic core complex. Thickness as much as much as 200 m (656 ft).
State Montana
Name Middle Tertiary sediment or sedimentary rock
Geologic age Tertiary
Lithologic constituents
Sedimentary > Clastic > Conglomerate (Bed)
Sedimentary > Clastic > Siltstone (Bed, Tuffaceous)
Sedimentary > Clastic > Sedimentary-breccia (Bed)
Sedimentary > Clastic > Mudstone > Claystone > Bentonite (Bed)
Sedimentary > Carbonate > Limestone (Bed)
Sedimentary > Clastic > Sandstone (Bed)
Igneous > Volcanic (Pyroclastic, Flow)ash beds, Local volcanic flows in southwestern Montana

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 - Broadwater - Gallatin - Granite - Jefferson - Judith Basin - Lewis and Clark - Madison - Meagher - Missoula - Powell - Ravalli - Silver Bow