Condrey Mountain Schist

Consists of a variety of schistose rocks characterized by different proportions of muscovite, quartz, graphite, chlorite, actinolite, and epidote, rare thin layers of metachert, and clinozoisite-actinolite-albite-garnet metagabbro. Potassium-argon age on muscovite from unit is about 141 Ma (Lanphere and others, 1968) and on a whole rock sample is about 155 Ma (Suppe and Armstrong, 1972), indicating a Late Jurassic metamorphic age. Protolith is probably Triassic and Paleozoic in age
State Oregon
Name Condrey Mountain Schist
Geologic age Paleozoic(?) to Jurassic
Lithologic constituents
Major
Metamorphic > Schist (Greenschist)Includes metasedimentary rocks (graphitic quartz-albite-muscovite schist) and metavolcanic greenschist.
Incidental
Sedimentary > Chemical > Chert (Bed)
Metamorphic > Metaigneous > Serpentinite
Metamorphic > Metaigneous > Metaintrusive > Metagabbro
References

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

Irwin, W.P., 1994, Geologic map of the Klamath Mountains, California and Oregon: U.S. Geological Survey Miscellaneous Investigations Series Map I-2148, scale 1:500,000.

https://pubs.er.usgs.gov/publication/i2148

Helper, M.A., 1986, Deformation and high P/T metamorphism in the central part of the Condrey Mountain window, north-central Klamath Mountains, California and Oregon, in Evans, B.W., and Brown, E.H., eds., Blueschists and eclogites: Geological Society of America Memoir 164, p. 125-141.

Coleman, R.G., Manning, C.E., Mortimer, N., Donato, M.M., and Hill, L.B., 1988, Tectonic and regional metamorphic framework of the Klamath Mountains and adjacent Coast Ranges, California and Oregon, in Ernst, W.G., ed., Metamorphism and crustal evolution of the western United States: Englewood Cliffs, N.J., Prentice-Hall, p. 1061-1097.

Saleeby, J..B., and Harper, G.D., 1993, Tectonic relations between the Galice Formation and the Condrey Mountain Schist, Klamath Mountains, Northern California, in Dunne, G.C., and McDougall, K.A., eds., Mesozoic paleogeography of the western United States - II: Pacific Section Society of Economic Paleontologists and Mineralogists, Book 71, p. 61-80.

Lanphere, M.A., Irwin, W.P., and Hotz, P.E., 1968, Isotopic age of the Nevadan orogeny and older plutonic and metamorphic events in the Klamath Mountains, California: Geological Society of America Bulletin, v. 79, p. 1027-1052.

Suppe, John, and Armstrong, R.L., 1972, Potassium-argon dating of Fransican metamorphic rocks: American Journal of Science, v. 272, p. 217-233.

NGMDB product
Counties Jackson