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Ultramafic and mafic intrusive rocks and serpentinized equivalents (Triassic and Paleozoic)

Peridotite, pyroxenite, gabbro, and norite. Light-green, gray, and black serpentine, mostly derived from peridotite; commonly highly sheared; in places includes some metavolcanic rocks and metamorphosed inclusions of keratophyre and chert. Includes ultramafic and mafic phases of the ophiolitic Canyon Mountain Complex of Thayer (1963; 1977) and Brown and Thayer (1966), alpine mafic rocks of Wolff (1965), gabbro of Ashley (1967), and serpentinite-matrix melange of Brooks and others (1983) and Ferns and others (1983):
State Oregon
Name Ultramafic and mafic intrusive rocks and serpentinized equivalents (Triassic and Paleozoic)
Geologic age Paleozoic to Triassic
Comments Not defined on the State map (OR001) in the northeastern Oregon, but mapped in Umatilla River Basin (OR291) as ultramafic rocks (Triassic and Permian?)
Primary rock type peridotite
Secondary rock type pyroxenite
Other rock types gabbro
Lithologic constituents
Major
Igneous > Plutonic (Pluton)Peridotite, pyroxenite, gabbro, norite, serpentinite, metavolcanic rocks, and serpentine-matrix melange
Igneous > Plutonic > Ultramafic > Peridotite (Pluton)
Minor
Igneous > Volcanic (Flow)Keratophyre
Sedimentary > Chemical > Chert (Bed)
Igneous > Plutonic > Ultramafic > Pyroxenite (Pluton)
Incidental
Igneous > Plutonic > Gabbroic > Gabbro > Norite (Pluton)
Map references
Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000.
Unit 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.
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., 1977, Geologic map of Oregon east of the 121st meridian: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-902, scale 1:500,000.
Thayer, T.P., 1963, The Canyon Mountain complex, Oregon, and the alpine mafic magma stem: U.S. Geological Survey Professional Paper 475-C, p. C82-C85.
Thayer, T., P., 1977, The Canyon Mountain Complex, Oregon, and some problems of ophiolites, in Coleman, R.G. and Irwin, W.P., North American Ophiolites: Oregon Department of Geology and Mineral Industries Bulletin 95, p. 93-105.
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.
Brooks, H.C., Ferns, M.L., Wheeler, G.R., and Avery, D.G., 1983, Geology and gold deposits map of the northeast quarter of the Bates quadrangle, Baker and Grant Counties, Oregon: Oregon Department of Geology and Mineral Industries Geologic Map Series GMS-7, scale 1:24,000.
Ferns, M.L., Brooks, H.C., and Avery, D.G., 1983, Geology and gold deposits of the Greenhorn quadrangle, Baker and Grant Counties, Oregon: Oregon Department of Geology and Mineral Industries Geologic Map Series GMS-28, scale 1: 24,000.
Brooks, H.C., 2006, Preliminary geologic map of the Mormon Basin quadrangle, Baker County, Oregon: Oregon Department of Geology and Mineral Industries Open-File Map O-06-25, scale 1:24,000.
Ferns, M.L., Brooks, H.C., and Avery, D.G., 1983, Geology and gold deposits map of the Greenhorn quadrangle, Baker and Grant Counties, Oregon: Oregon Department of Geology and Mineral Industries Geologic Map Series GMS-28, scale 1:24,000.
Brooks, H.C., Ferns, M.L., and Avery, D.G., 1984, Geology and gold deposits of the southwest quarter of the Bates quadrangle, Grant County, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-35, scale 1:24,000.
Ferns, M.L., Brooks, H.C., and Wheeler, G.R., 1984, Geology and gold deposits of the Bates quadrangle, Grant County, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-31, scale 1:24,000.
Brooks, H.C., Ferns, M.L., Wheeler, G.R., and Avery, D.G., 1983, Geology and gold deposits map of the northeast quarter of the Bates quadrangle, Baker and Grant Counties, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-29, scale 1:24,000
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.
Brooks, H.C. and Ferns, M.L., 1979, Geologic map of the Bullrun Rock quadrangle, Baker and Grant Counties, Oregon: Oregon Department of Geology and Mineral Industries Open-File Map O-79-6, scale 1:24,000.
Evans, J.G., 1994, unpub. mapping, Hereford quadrangle, Baker County, Oregon.
Brooks, H.C., Ferns, M.L., Nusbaum, R.L., and Kovich, P.M., 1979, Geologic map of the Rastus Mountain quadrangle, Baker and Grant Counties, Oregon: Oregon Department of Geology and Mineral Industries Open-File Map O-79-7, scale 1:24,000.
Ferns, M.L., Brooks, H.C., and Avery, D.G., 1983, Geology and gold deposits map of the Greenhorn Quadrangle, Baker and Grant Counties, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-28, scale 1:24,000.
Thayer, T.P., Brown, C.E., and Hay, R.I., 1967, Preliminary geologic map of the Prairie City quadrangle, Grant County, Oregon: U.S. Geological Survey Open-File Map, scale 1:62,500.
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.
Counties Baker - Grant