Volcanic rocks

Massive flows of porphyritic meta-andesite, metabasalt, spilite, and keratophyre, volcanic breccia, and subordinate amounts of fine-grained volcaniclastic rocks. In eastern Oregon probably mostly Late Triassic in age, but includes some Permian rocks (OR084). Includes Clover Creek Greenstone (OR035), Gold Creek greenstone (informal name; OR029), and greenstone of Ashley (OR081)
State Oregon
Name Volcanic rocks
Geologic age Permian to Triassic
Lithologic constituents
Major
Metamorphic > Hydrothermally-altered > Spilite
Metamorphic > Metaigneous > Metavolcanic > Metabasalt
Metamorphic > Metaigneous > Metavolcanic > Metaandesite
Minor
Igneous > Volcanic (Flow)Keratophyre
Igneous > Volcanic > Mafic-volcanic (Volcaniclastic-volcanic breccia)
Metamorphic > Metaigneous > Greenstone (Greenschist)
Stratigraphic units Clover Creek Greenstone (OR035), Gold Creek Greenstone (OR029)
References

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

Brown, C.E. and Thayer, T.P., 1966, Geologic map of the Canyon City quadrangle, northeastern Oregon: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-447, scale 1:250,000.

https://pubs.er.usgs.gov/publication/i447

Prostka, H.J., 1962, Geology of the Sparta quadrangle, Oregon: Oregon Department of Geology and Mineral Industries Geologic Map Series GMS-1, scale 1:62,500.

Gilluly, James, 1937, Geology and mineral resources of the Baker quadrangle, Oregon: U.S. Geological Survey Bulletin 879, 199 p.

https://pubs.er.usgs.gov/publication/b879

Brooks, H.C., McIntyre, J.R., and Walker, G.W., 1976, Geology of the Oregon part of the Baker 1o by 2o quadrangle: Oregon Department of Geology and Mineral Industries Geologic Map Series GMS-7, scale 1:250,000.

Walker, G.W., 1979, Reconnaissance geologic map of the Oregon part of the Grangeville quadrangle, Baker, Union, Umatilla, and Wallowa Counties, Oregon: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-1116, scale 1;250,000.

https://pubs.er.usgs.gov/publication/i1116

Walker, G.W., 1973, Reconnaissance geologic map of the Pendleton quadrangle, Oregon and Washington: U.S. Geological Survey Miscellaneus Geologic Investigations Map I-727, scale 1:250,000.

https://pubs.er.usgs.gov/publication/i727

Walker, G.W., 1977, Geologic map of Oregon east of the 121st meridian: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-902, scale 1:500,000.

https://pubs.er.usgs.gov/publication/i902

Wolff, E.N., 1965, The geology of the northern half of the Caviness quadrangle, Oregon: Eugene, University of Oregon, Ph.D. dissertation, 214 p.

Ashley, R.P., 1967, Metamorphic petrology and structure of the Burnt River Canyon area, northeastern Oregon: Stanford, California, Stanford University, Ph.D. dissertation, 236 p.

Evans, J.G., 1989, Geologic map of the Desolation Butte quadrangle, Grant and Umatilla Counties, Oregon: U.S. Geological Survey Geologic Quadrangle GQ-1654, scale 1:62,500.

https://pubs.er.usgs.gov/publication/gq1654

Ferns, M.L., Madin, I.P., and Taubeneck, W.H., 2001, Reconnaissance geologic map of the La Grande 30' x 60' quadrangle, Baker, Grant, Umatilla, and Union Counties, Oregon: Oregon Department of Geology and Mineral Industries Reconnaissance Map Series RMS-1, 52 p., scale 1:100,000.

Weiss, P.L., Gualtieri,, J.L., Cannon, W.F., Tucher, E.T., McMahan, A.B., and Federspiel, F.E., 1976, Mineral resources of the Eagle Cap Wilderness and adjacent areas, Oregon: U.S. Geological Survey Bulletin 1385-E, 100 p.

https://pubs.er.usgs.gov/publication/b1385E

NGMDB product
Counties Baker - Grant - Umatilla - Union - Wheeler