Gabbroic rocks

Most gabbro genetically related to ultramafic rocks, but some probably derived from metamorphism of Triassic and older volcanic rocks
State Oregon
Name Gabbroic rocks
Geologic age Paleozoic to Triassic
Lithologic constituents
Major
Igneous > Plutonic > Gabbroic > Gabbro (Pluton)
Minor
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow)
Comments Not present on State map (OR001) in northeastern Oregon, but, in La Grande 30' x 60' quadrangle (OR291) may be mapped as amphibolite, metagabbro, and metadiorite (Triassic and Permian)
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.

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.

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.

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.

Evans, J.G., Geologic map of the Dooley Mountain quadrangle, Baker County, Oregon: U.S. Geological Survey Geological Quadrangle GQ-1694, scale 1: 24,000.

https://pubs.er.usgs.gov/publication/gq1694

Ferns, M.L. and Brooks, H.C., 1987, Geology and mineral resources map of the Elkhorn Peak quadrangle, Baker County, Oregon: Oregon Department of Geology and Mineral Industries Geologican Map Series GMS-41, 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

Brooks, H.C., Ferns, M.L., Coward, R.I., Paul, E.K., and Nunlist, M., 1982, Geology and gold deposits map of the Bourne quadrangle, Baker and Grant Counties, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-19, scale 1:24,000.

Swisher, C.C., Ach, J.A., and Hart, W.K., 1990, Laser fusion 40Ar/39Ar dating of the type Steens Mountain Basalt, southeastern Oregon, and the age of the Steens aeromagnetic polarity transition [abs.]: EOS, Transactions of American Geophysical Union, v. 17, no. 43, p. 1,296.

Brooks, H.C., 1979, Geologic map of the Oregon part of the Mineral quadrangle: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-12, scale 1:62,500.

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.

Whitsun, N.W., 1988, Geochemical stratigraphy of the Dooley Rhyolite Breccia and Tertiary basalts in the Dooley Mountain quadrangle, Oregon: Portland, Oregon, Portland State University, master's thesis, 122 p.

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.

NGMDB product
Counties Baker - Grant - Malheur - Wheeler