Basalt (upper and middle Miocene)

Basalt flows, flow breccia, and basaltic peperite; minor andesite flows; some interbeds of tuff and tuffaceous sedimentary rocks. Basalt is aphyric to moderately porphyritic with phenocrysts of plagioclase and olivine and exhibits both subophitic and diktytaxitic textures. Includes Picture Rock Basalt of Hampton (1964), radiometrically dated by potassium-argon methods as middle(?) and late Miocene in age (see Fiebelkorn and others, 1983), flows of Deer Butte Formation of Kittleman and others (1967), and extensive unnamed flow sequences in the Basin-Range and Owyhee Upland Provinces of southern Lake, Harney, and Malheur Counties that are younger than Steens Basalt, dated at about 15 Ma (Baksi and others, 1967) and the Owyhee Basalt, dated at about 14 Ma (Bottomley and York, 1976; see also Fiebelkorn and others, 1983), and older than 7 or 8 Ma. Partly coeval with the Saddle Mountains Basalt of the Columbia River Basalt Group (Swanson and others, 1979)
State Oregon
Name Basalt (upper and middle Miocene)
Geologic age Middle to Late Miocene
Primary rock type basalt
Secondary rock type andesite
Other rock types tuff; mixed clastic/volcanic
Lithologic constituents
Major
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Minor
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow)
Sedimentary > Clastic > Mixed-clastic (Bed)
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic, air fall)
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.
Walker, G.W. and Repenning, C.A., 1966, Geologic map of the west half of the Jordan Valley quadrangle, Malheur County, Oregon: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-457, scale 1:250,000.
Greene, R.C., Walker, G.W., and Corcoran, R.E., 1972, Geologic map of the Burns quadrangle, Oregon: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-680, scale 1:250,000.
Walker, G.W. and Repenning, C.A., 1965, Geologic map of Adel quadrangle, Lake, Harney, and Malheur Counties, Oregon: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-446, scale 1:250,000.
Ferns, M.L., Evans, J.G., and Cummings, M.L., 1993a, Geologic map of the Mahogany Mountain 30 x 60 minute quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-78, scale 1:100,000.
Ferns, M.L., Brooks, H.C., Evans, J.G., and Cummings, M.L., 1993b, Geologic map of the Vale 30 x 60 minute quadrangle, Malheur County Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-77, scale 1:100,000.
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.
Fiebelkorn, R.B., Walker, G.W., Macleod, N.S., McKee, E.H., and Smith, J.G., 1983, Index to K-Ar determinations for the State of Oregon: Isochron/West, no. 37, p. 3-60.
Kittleman, L.R., Green, A.R., Hagood, A.R., Johnson, A.M., McMurray, J.M., Russell, R.G., and Weeden, D.A., 1965, Cenozoic stratigraphy of the Owyhee region, southeastern Oregon: Eugene, University of Oregon Museum of Natural History Bulletin 1, 45 p.
Kittleman, L.R., Green, A.R., Haddock, G.H., Hagood, A.R., Johnson, A.M., McMurray, J.M., Russell, R.G., and Weeden, D.A., 1967, Geologic map of the Owyhee region, Malheur County, Oregon: Eugene, University of Oregon Museum of Natural History Bulletion 8, scale 1:125,000
Baksi, A.K., York, D., and Watkins, N.D., 1967, Age of Steens Mountain geomagnetic polarity transition: Journal of Geophysical Research, v. 72, p. 6,299-6,308.
Bottomly, R.J. and York, Derek, 1976, 40Ar/39Ar age determinations on the Owyhee Basalt of the Columbia Plateau: Earth and Planetary Science Letters, v. 31, p. 75-84.
Swanson, D.A., Wright, T.L., Hooper, P.R., and Bentley, R.D., 1979, Revisions in stratigraphic nomenclatire of the Columbia River Basalt Group: U.S. Geological Survey Bulletin1457-G, p. G1-G59.
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.
Walker, G.W., Peterson, N.V., and Greene, R.C., 1967, Reconnaissance geologic map of the east half of the Crescent quadrangle, Lake, Deschutes, and Crook Counties, Oregon: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-493, scale 1:250,000.
Evans, J.G., 1990a, Geology and mineral resources map of the Jonesboro Quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Geologic Map Series GMS-66, scale 1:24,000.
Evans, J.G., 1990b, Geology and mineral resources map of the South Mountain quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Geologic Map Series GMS-67, scale 1:24,000.
Bryan, K., 1929, Geology of reservoir and dam sites, with a report on the Owyhee Irrigation Project, Oregon: U.S. Geological Survey Water-Supply Paper 597-A, 72 p.
Ferns, M.L., 1989, Geology and mineral resources map of the Owyhee Dam quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-55, scale 1:24,000.
Ferns, M.L., Brooks, H.C., and Ducette, J., 1982, Geology and mineral resources map of the Mt. Ireland quadrangle, Baker and Grant Counties, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series, GMS-22, 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.
Ferns, M.L. and Cummings, M.L., 1992, Geology and mineral resources map of The Elbow quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-62, scale 1:24,000.
Ferns, M.L. and O'Brien, J.P., 1992, Geology and mineral resources map of the Harper quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-69, scale 1:24,000.
Brooks, H.C. and O'Brien, J.P., 1992, Geology and mineral resources map of the Harper quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-71, scale 1:24,000.
Cummings, M.L., 1991, Relations among volcaniclastic sedimentation, volcanism, faulting, and hydrothermal activity east of Lake Owyhee, Malheur County, Oregon, in Rains, G., Lisle, R.E, Schafer, R.W., and Wilkinson, W.M., eds., Geology and ore deposits of the Great Basin, Symposium Proceedings: Geological Society of Nevada, v. 1, p. 111-132.
Cummings, M.L., 1991, Geology of the Deer Butte Formation, Malheur County, Oregon: faulting, sedimentation, and volcanism in a post-caldera setting: Sedimentary Geology, v. 74, p. 345-362.
Watkins, N.D. and and Baksi, A.K., 1974, Magnetostratigraphy and oroclinal folding of the Columbia River, Steens, and Owyhee Basalts in Oregon, Washington, and Idaho: American Journal of Science, v.274, no. 2, p. 148-189.
Hart,W.K., 1982, Chemical, geochronologic, and isotopic significance of low-K, high-alumina olivine tholeiite in the northwestern Great Basin, U.S.A.: Cleveland, Ohio, Case Western Reserve University, Ph.D. dissertation, 410 p.
Barrash, Warren, Bond, J.G., Kauffmann, J.D., and Venkatakrishnan, Ramesh, 1980, Geology of the La Grande area, Oregon: Oregon Department of Geology and Mineral Industries Special Paper 6, 67 p., 4 maps, scale 1:24,000.
Evans, J.G., 1996, Geologic map of the Monument Peak quadrangle, Malheur County, Oregon: U.S. Geological Survey Miscellaneous Field Studies Map MF-2317, scale 1:24,000.
Evans, J.G. and Keith, W.J., 1996, Geologic map of the Tims Peak quadrangle, Malheur County, Oregon: U. S. Geological Survey Miscellaneous Field Studies Map MF-2316, scale 1:24,000.
Sherrod, D.R. and Johnson, J.A., 1994, Geologic map of the Irish Lake quadrangle, Harney County, south-central Oregon: U.S. Geological Survey Miscellaneous Field studies Map MF-2256, scale 1:24,000.
Cummings, M.L., 1993, Geologic map of the Sourdough Springs quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Open-File Report O-93-11, scale 1:24,000.
Ferns, M.L., 1992, Preliminary geologic map of the Cedar Mountain quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Open-File Map O-92-05, scale 1:24,000.
Brooks, H.C., 1992, Preliminary geologic map of the Avery Creek quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Open-File Map O-92-16, scale 1:24,000.
Ferns, M.L. and Evans, J.G., 1993c, Preliminary geologic map of the Rinehart Canyon quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Open-File Map O-93-5, scale 1: 24,000.
Ferns, M.L. and O'Brien, J.P., 1991, Preliminary geologic map of the Keeney Ridge quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Open-File Map O-91-3, scale 1:24,000.
Ferns, M.L. and O'Brien, J.P., 1992, Geology and mineral resources map of the Namorf quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-74, scale 1:24,000.
Ferns, M.L. and Williams, C.P., 1993, Preliminary geologic map of the Burnt Flat quadrangle, Malheur County, Oregon: Oregon Department of Geology and Mineral Industries Open-File Map O-93-2, scale 1:24,000.
McMurray, J.M., 1962, Geology of the Freezeout Mountain area, Malheur County, Oregon: Eugene, University of Oregon, master's thesis, 87 p.
Plumley, P.S., 1986, Volcanic stratigraphy and geochemistry of the Hole in the Ground area, Owyhee Plateau, southeastern Oregon: Moscow, University of Idaho, master's thesis, 161 p.
Camp, V.E., Ross, M.E., and Hanson, W.E., 2003, Genesis of flood basalts and Basin and Range volcanic rocks from Steens Mountain to the Malheur River Gorge, Oregon: Geological Society of America Bulletin, v. 115, no. 1, p. 105-128.
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Johnson, J.A., Hooper, P.R., Hawkesworth, C.J., and Binger, G.B., 1998b, Geologic map of the Stemmler Ridge quadrangle, Malheur County, Oregon: U.S. Geological Survey Open-File Report 98-105, scale 1:24,000.
Rytuba, J.J., Minor, S.A., Conrad, W.K., and Vander Meulen, D.B., 1982, Geologic map of the Trout Creek Canyon quadrangle, Harney County, Oregon: U.S. Geological Survey Open-File Report 82-281, scale 1:24,000.
Rytuba, J.J., Minor, S.A., Miller, R.J., and Vander Meulen, D.B., 1983, Geologic map of the Red Mountain quadrangle, Harney County, Oregon: U.S. Geological Survey Open-File Report 83-0282, scale 1:24,000.
Rytuba, J.J., Minor, S.A., Miller, R.J., and Vander Meulen, D.B., 1983, Geologic map of the Red Lookout Butte quadrangle, Harney County, Oregon: U.S. Geological Survey Open-File Report 83-0283, scale 1:24,000.
Rytuba, J.J., Minor, S.A., and Vander Meulen, D.B., 1983, Geologic map of the Pole Canyon quadrangle, Harney County, Oregon: U.S.Geological Survey Open-File Report 83-0285, scale 1:24,000.
Vander Meulen, D.B., Rytuba, J.J., Grubensky, M.J., and Goeldner, C.A., 1987, Geologic map of the Bannock Ridge 7.5' quadrangle, Malheur County, Oregon: U.S. Geological Survey Miscellaneous Field Studies Map MF-1903A, scale 1:24,000.
Vander Meulen, B.B., Rytuba, J.J., Grubensky, M.J., Vercoutere, T.L., and Minor, S.A., 1987, Geologic map of the Pelican Point quadrangle, Malheur County, Oregon: U.S. Geological Survey Miscellaneous Field Studies Map MF-1904, scale 1:24,000.
Vercoutere, T.L., Vander Meulen, D.B., and Minor, S.A., 1987, Geologic map of the Diamond Butte quadrangle, Malheur County, Oregon: U.S. Geological Survey Miscellaneous Field Studies Map MF-1901, scale 1:24,000.
Weeden, D.A., 1963, Geology of the Harper area, Malheur County, Oregon: Eugene, University of Oregon, master's thesis, 94 p.
Berry, N.J., 1956, Geology of the northeast quarter of the Huntington quadrangle, Oregon: Eugene, University of Oregon, master's thesis, 78 p.
Counties Baker - Crook - Grant - Harney - Jefferson - Klamath - Lake - Malheur - Wasco