Terrace, pediment, and lag gravels (ORQt;0)

State	Oregon
Name	Terrace, pediment, and lag gravels
Geologic age	Pleistocene to Holocene
Lithologic constituents	Major Unconsolidated > Coarse-detrital > Boulders (Terrace-stream) Unconsolidated > Fine-detrital > Clay (Terrace-stream) Unconsolidated > Coarse-detrital > Gravel (Terrace-stream) Minor Unconsolidated > Coarse-detrital > Sand (Terrace-stream) Unconsolidated > Fine-detrital > Silt (Terrace-stream)
Comments	In OR291, includes terrace levels 60 m and 20-30 m above Grande Ronde Valley floor. Lower terrace dated as Pleistocene based on radiocarbon date of a mammoth tooth of 15,280+180 yr B.P. In OR292, includes a terrace that stands 20 m above the modern valley floor along the south side of the Umatilla River. Gravel also deposited above the present channel of the middle reach of the Umatilla River
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. https://pubs.er.usgs.gov/publication/i457 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. https://pubs.er.usgs.gov/publication/i446 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., 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 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. 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. Evans, J.G., Geologic map of the Beaverdam Creek quadrangle, Baker County, Oregon: U.S. Geological Survey Miscellaneous Field Studies Map MF-2299, scale 1:24,000. https://pubs.er.usgs.gov/publication/mf2299 Evans, J.G., 1993, unpub. mapping, Unity Reservoir quadrangle, Baker County Oregon. Rytuba, J.J. and Curtis, D.L., Jr., 1983, Geologic map of the Oregon Canyon 3NW [Oregon Canyon Ranch] quadrangle, Malheur County, Oregon: U.S. Geological Survey Miscellaneous Field Studies Map MF-1473, scale 1:24,000. https://pubs.er.usgs.gov/publication/mf1473 Reef, J.W., 1983, The Unity Reservoir rhyodacite, tuff-breccia and associated volcanic rocks, Baker County, Oregon: Pullman, Washington State University master's thesis, 128 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. 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. Madin, I.P., 1998, Geologic map of the Tucker Flat quadrangle, Union and Baker Counties, Oregon: Oregon Department of Geology and Mineral Industries Geological map Series GMS-110, scale 1;24,000.
NGMDB product	NGMDB product page for 16259
Counties	Baker - Benton - Clackamas - Clatsop - Coos - Crook - Curry - Douglas - Grant - Harney - Jackson - Josephine - Lake - Lane - Lincoln - Linn - Malheur - Marion - Polk - Tillamook - Union

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.

https://pubs.er.usgs.gov/publication/i457

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.

https://pubs.er.usgs.gov/publication/i446

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., 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

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.

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.

Evans, J.G., Geologic map of the Beaverdam Creek quadrangle, Baker County, Oregon: U.S. Geological Survey Miscellaneous Field Studies Map MF-2299, scale 1:24,000.

https://pubs.er.usgs.gov/publication/mf2299

Evans, J.G., 1993, unpub. mapping, Unity Reservoir quadrangle, Baker County Oregon.

Rytuba, J.J. and Curtis, D.L., Jr., 1983, Geologic map of the Oregon Canyon 3NW [Oregon Canyon Ranch] quadrangle, Malheur County, Oregon: U.S. Geological Survey Miscellaneous Field Studies Map MF-1473, scale 1:24,000.

https://pubs.er.usgs.gov/publication/mf1473

Reef, J.W., 1983, The Unity Reservoir rhyodacite, tuff-breccia and associated volcanic rocks, Baker County, Oregon: Pullman, Washington State University master's thesis, 128 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.

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.

Madin, I.P., 1998, Geologic map of the Tucker Flat quadrangle, Union and Baker Counties, Oregon: Oregon Department of Geology and Mineral Industries Geological map Series GMS-110, scale 1;24,000.