Otter Point Formation of Dott (1971) and related rocks

Highly sheared graywacke, mudstone, siltstone, and shale with lenses and pods of sheared greenstone, limestone, chert, blueschist, and serpentine. Identified as melange by some investigators
State Oregon
Name Otter Point Formation of Dott (1971) and related rocks
Geologic age Late Jurassic
Lithologic constituents
Sedimentary > Clastic > Sandstone > Graywacke (Bed)Graywacke contains abundant volcanic detritus
Sedimentary > Clastic > Mudstone (Bed)
Sedimentary > Clastic > Conglomerate
Sedimentary > Carbonate > Limestone
Metamorphic > Metaigneous > Serpentinite
Metamorphic > Schist (Glaucophane-schist)
Metamorphic > Metaigneous > Greenstone
Sedimentary > Chemical > Chert
Comments Considered part of the Gold Beach Terrane by Blake and others (1985).

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

Coleman, R.G., 1972, The Colebrooke Schist of southwestern Oregon and its relation to the tectonic evolution of the region: U.S. Geological Survey Bulletin 1972, 61 p.

Blake, M.C., Jr., Engebretson, D.C., Jayko, A.S., and Jones, D.L., 1985, Tectonostratigraphic terranes in southwest Oregon, in Howell, D.G., ed., Tectonostratigraphic terranes of the circum-Pacific region: Circum-Pacific Council for Energy and Mineral Resources Earth Science Series, v. 1, p. 147-158.

Dott, R.H., Jr., 1971, Geology of the southwestern Oregon coast west of the 124th meridian: Oregon Department of Geology and Mineral Industries Bulletin 69, 63 p.

Koch, J.G., 1966, Late Mesozoic stratigraphy and teconic history, Port Orford-Gold Beach area, southwestern Oregon coast: American Association of Petroleum Geologists Bulletin, v. 50, p. 25-71.

NGMDB product
Counties Coos - Curry - Douglas