Pre-Tertiary metamorphic rocks, undivided

Schist, gneiss, marble, quartzite, amphibolite, greenstone, metaconglomerate, graywacke; includes metasedimentary, volcanic, and intrusive rocks. Some areas, as on San Juan Islands, show little if any metamorphism.
State Washington
Name Pre-Tertiary metamorphic rocks, undivided
Geologic age Probably Permian
Lithologic constituents
Metamorphic > MetasedimentaryIncludes metaconglomerate, meta-argillite, metawacke, metalimestone, metadolostone, and metasiltite (metasiltstone).
Metamorphic > Gneiss
Metamorphic > Schist
Metamorphic > Granoblastic > Hornfels
Metamorphic > Metasedimentary > Metaclastic > PhyllitePossibly minor in rank.
Metamorphic > Metaigneous > Greenstone
Igneous > Plutonic > Gabbroic > Gabbro (Pluton)
Metamorphic > Amphibolite
Igneous > Plutonic > Granitic > Tonalite (Pluton)
Sedimentary > Carbonate > Limestone (Lens)
Metamorphic > Metasedimentary > Metacarbonate > MarblePossibly minor in rank.
Metamorphic > Metasedimentary > Metaclastic > Slate
Metamorphic > Metasedimentary > Metaclastic > QuartzitePossibly minor in rank.
Comments Outcrops in Okanogan County are mostly metasedimentary rocks, including metawacke, metalimestone, metadolostone, metasiltite, meta-argillite, and metaconglomerate, as well as black slate, phyllite, gneiss, schist, quartzite, amphibolite, and greenstone; outcrops near Spokane consist of phyllite, metalimestone, quartzite, and metasiltite, with alteration to calc-silicate rocks, schist, marble, and hornfels (Stoffel and others, 1991). Tonalite and gabbro in San Juan Islands and possibly in Chelan County (Brandon, 1989)
Stratigraphic units Anarchist series (Bullfrog Mountain Formation, Spectacle Formation); Turtleback complex (in small part); Fildalgo complex (in small part); Chiwaukum Schist (in part)

Huntting, M.T., Bennett, W.A.G., Livingston, V.E.Jr., and Moen, W.S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000.

Stoffel, K.L., Joseph, N.L., Waggoner, S.Z., Gulick, C.W., Korosec, M.A., Bunning, B.B., 1991, Geologic Map of Washington--Northeast Quadrant: Washington Division of Geology and Earth Resources Geologic Map, GM-39, scale 1:250,000.

Brandon, M.T., 1989, Geology of the San Juan-Cascade Nappes, northwestern Cascade Range and San Juan Islands, in Joseph, N. L. (Ed.), Geologic Guidebook for Washington and Adjacent Areas: prepared for the 85th Annual Meeting of the Cordilleran Section, Geological Society of America, May 8-11, 1989, Spokane, Washington: Washington Division of Geology and Earth Resource Infomation Circular 86, p. 137-162.

Rinehart, C.D., and Fox, K.F.Jr., 1972, Geology and Mineral Deposits of the Loomis Quadrangle, Okanogan County, Washington: Washington Division of Mines and Geology Bulletin No. 64, 124 p.

Dragovich, J.D., Logan, R.L., Schasse, H.W., Walsh, T.J., Lingley, W.S., Jr., Norman, D.K., Gerstel, W.J., Lapen, T.J., Schuster, J.E., Meyers, K.D., 2002, Geologic Map of Washington-Northwest Quadrant: Washington Division of Geology and Earth Resources Geologic Map GM-50, scale 1:250,000.

NGMDB product
Counties Chelan - Lincoln - Okanogan - San Juan - Skagit - Spokane - Stevens - Whatcom