Marine sandstone, siltstone, and mudstone

Rhythmically interbedded sandstone, siltstone, and mudstone with minor conglomerate; deposited in deep-sea fan depositional setting on submarine basalts of the Siletz River Volcanics. Contains foraminiferal faunas referred to the Penutian Stage of early Eocene age and locally contains assemblages of probable Paleocene age (McKeel and Lipps, 1975; P.D. Snavely, Jr. and David Bukry, written communication, 1980). Included by Diller (1898) in the Umpqua Formation; Baldwin (1974) and Ryberg (1984) mostly mapped unit as sedimentary rocks of the Roseburg Formation of the Umpqua Group; according to Heller and Ryberg (1983) and Molenaar (1985), may be partly correlative with the Lookingglass Formation of Baldwin (1974). Includes lower Eocene-Paleocene turbidite sedimentary rocks exposed at Five Mile Point, about 11 km north of Bandon, that are considered by Snavely and others (1980) to represent allochtonous terrane
State Oregon
Name Marine sandstone, siltstone, and mudstone
Geologic age Paleocene to Early Eocene
Lithologic constituents
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Clastic > Siltstone (Bed)
Sedimentary > Clastic > Mudstone (Bed)
Sedimentary > Clastic > Conglomerate (Bed)

Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000.

McKeel, D.R., and Lipps, J.H., 1975, Eocene and Oligocene planktonic foraminifera from the central and southern Oregon Coast Range: Journal of Foraminiferal Research, v. 5, p. 249-269.

Diller, J.S., 1898, Roseburg [quadrangle], Oregon, folio 49 of the Geologic Atlas of the United States: U.S. Geological Survey, scale 1:125,000.

Baldwin, E.M., 1974, Eocene stratigraphy of southwestern Oregon: Oregon Department of Geology and Mineral Industries Bulletin 83, 40 p.

Ryberg, P.T., 1984, Sedimentation, structure and tectonics of Umpqua Group (Paleocene to Early Eocene), southwestern Oregon: Tucson, Arizona, University of Arizona, Ph.D. dissertation, 280 p.

Heller, P.L., and Ryberg, P.T., 1983, Sedimentary record of subduction to forearc transition in the rotated Eocene basin of western Oregon: Geology, v. 11, p. 380-383.

Molenaar, C.M., 1985, Depositional relations of Umpqua and Tyee Formations (Eocene), southwest Oregon: American Association of Petroleum Geologists Bulletin, v. 69, p. 1217-1229.

Snavely, P.D., Jr., Wagner, H.C., and Lander, D.L., 1980, Geologic cross section of the central Oregon continental margin: Geological Society of America Map and Chart Series MC-28J, p. 3-8.

NGMDB product
Counties Coos - Curry - Douglas