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Livingston formation

Livingston formation: water-laid volcanic material, mainly andesitic in composition; includes agglomerate, conglomerate, sandstone, and shale. The name here is used only for the rocks orginally named, mainly near and north of Livingston. These rocks include age equivalents of various Cretaceous and Paleocene units.
State Montana
Name Livingston formation
Geologic age Phanerozoic | Cenozoic | Tertiary Cretaceous
Comments Unit as mapped includes large area surrounding the Crazy Mountains that is now known to consist of Fort Union Formation (Paleocene).
Primary rock type volcanic rock (aphanitic)
Secondary rock type fine-grained mixed clastic
Other rock types medium-grained mixed clastic
Lithologic constituents
Igneous > VolcanicThe unit as mapped includes a wide variety of igneous rock types and forms, including intrusive and extrusive varieties. Rock types are mainly andesitic, but range from felsic to intermediate to felsic. Forms include domes, plugs, sills, dikes, tuffs, lava flows and a lot of agglomerate (lahars). These are interlayered with true clastic sedimentary rocks that were reworked from the stratavolcanoes.
Sedimentary > Clastic > Mixed-clastic > Sandstone-Mudstone (Bed)
Sedimentary > Clastic > Mixed-clastic > Conglomerate-sandstone (Bed)
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
Roberts, A.E., 1972, Cretaceous and early Tertiary depositional and tectonic history of the Livingston area, southwestern Montana, in Geology of the Livingston area, southwestern Montana: U.S. Geological Survey Professional Paper 526-C, p. C1
du Bray, E.A., Elliott, J.E., Van Gosen, B.S., LaRock, E.J., and West, A.W., 1994, Reconnaissance geologic map of the Sliderock Mountain area, Sweet Grass and Stillwater Counties, Montana: U.S. Geological Survey Miscellaneous Field Studies Map MF-2259, 1
Vuke, S.M., Berg, R.B., Colton, R.B., O'Brien, H.E., 2002, Geologic map for the Belt 30' x 60' quadrangle, central Montana: Montana Bureau of Mines and Geology Open File Report 450, 16 p., scale 1:100,000.
Berg, R.B., Lopez, D.A., 2000, Geologic map of the Livingston 30' x 60' quadrangle, south-central Montana: Montana Bureau of Mines and Geology Open File Report 406, scale 1:100,000.
McGrew, L.W., 1977, Geologic map of the Ringling quadrangle, Meagher County, Montana: U.S. Geological Survey Geologic Quadrangle Map 1382, scale 1:24,000.
Skipp, Betty and McGrew, L.W., 1977, The Maudlow and Sedan Formations of the Upper Cretaceous Livingston Group at the west edge of the Crazy Mountains basin, Montana, in Contributions to stratigraphy: U.S. Geological Survey Bulletin 1422-B, p.
Langston, R.B., 1985, Volcanic stratigraphy of part of the Upper Cretaceous Livingston Formation: Northwest Geology, v. 14, p. 11-15.
Parsons, W.H., 1942, Origin and structure of the Livingston igneous rocks, Montana: Geological Society of America Bulletin, v. 53, p. 1175-1185.
Richards, P.W., 1957, Geology of the area east and southeast of Livingston, Park County, Montana: U.S. Geological Survey Bulletin 1021-L, p. 385-438.
Counties Gallatin - Meagher - Park - Sweet Grass