|Geologic age||Middle Miocene|
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
|Comments||In La Grande 30' x 60' quadrangle (OR291), unit includes only the Frenchman Springs Member. In the Umatilla River Basin (OR292), includes the basalt of Powatka, Frenchman Springs Member, Sentinel Gap unit, Sand Hollow unit, and basalt of Lookingglass.|
Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000.
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.
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.
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.
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.
Lux, D.R., 1982, K-Ar and 40Ar/39Ar ages of mid-Tertiary volcanic rocks from the Western Cascade Range, Oregon: Isochron/West, no. 33, p. 27-32.
Wright, T.L., Grolier, M.J., and Swanson, D.A., 1973, Chemical variation related to stratigrphy of the Columbia River Basalt: Geological Society of America Bulletin, v. 84, p. 371-386.
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.
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.
Ferns, M.L., McConnell, V.S., and Madin, I.P., in prep., Geology of the Umatilla River Basin, Morrow, Umatilla, and Union Counties, Oregon: Oregon Department of Geology and Mineral Industries Open-File Report, 66 p., scale 1:100,000.
Brown, D.E., Black, G.L., and McLean, G.D., 1980, Preliminary geology and geothermal resource potential of the Craig Mountain-Cove area, , Oregon: Oregon Department of Geology and Mineral Industries Open-File Report O-80-04, 68 p., 1 map.
Ferns, M.L. and Madin, I.P., 1999, Geologic map of the Summerville quadrangle, Union County, Oregon: Oregon Department of Geology and Mineral Industries Geological Map Series GMS-111, scale 1:24,000.
|Counties||Baker - Clackamas - Clatsop - Columbia - Gilliam - Grant - Harney - Hood River - Marion - Morrow - Sherman - Umatilla - Union - Wallowa - Wasco - Washington - Yamhill|