Volcanic and metavolcanic rocks (ORTRv;0)

State	Oregon
Name	Volcanic and metavolcanic rocks
Geologic age	Late Triassic
Lithologic constituents	Major Igneous > Volcanic (Flow)Keratophyre Metamorphic > Hydrothermally-altered > Spilite Minor Sedimentary > Chemical > Chert (Bed) Sedimentary > Clastic > Siltstone (Bed) Sedimentary > Carbonate > Limestone (Bed) Sedimentary > Clastic > Conglomerate (Bed) Sedimentary > Clastic > Sandstone (Bed, Tuffaceous)coarse volcaniclastic sandstone, tuff, sandstone Metamorphic > Metaigneous > MetavolcanicIncludes Late Triassic "andesitic and basaltic rocks" of Nolf and Taubeneck (1963), and the basaltic to rhyolitic metavolcanic rocks
Comments	Huntington Formation (OR073) is predominantly agglomerate, tuff, and flows intercalated with coarse volcaniclastic breccia and conglomerate. Also contains volcanic graywacke, volcanic arenite, water-laid tuff, volcanic siltstone, and minor limestone. Volcanic rocks range from basalt to rhyolite; andesite is the most common lithology. Fine-grained sedimentary rocks typically form bedded sequences ranging from a few meters to a few hundred meters thick. Includes dikes, sills, and irregular shallow intrusive bodies that are difficult to distinguish from extrusive rocks. The rocks have been metamorphosed to the zeolite and greenschist facies of regional metamorphism. Fossil ammonites and Halobia indicate marine depositioon and late Carnian to late middle Norian (late Triassic) age (OR073). A Lead-uranium age of 235 Ma for an intrusive tonalite in the Huntington Formation indicates that part of the unit is Middle Triassic or older (OR190). The unit is interpreted as a product of a Triassic volcanic arc that makes up the Olds Ferry terrane (OR089)..
Stratigraphic units	Huntington Formation (OR073)
References	Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000. 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., 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., 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 Brooks, H.C., 1979, Geologic map of the Huntington and part of the Olds Ferry quadrangles, Baker and Mlheur Counties, Oregon: Oregon Department of Geology and Mineral Industries Geologic Map Series, GMS-13, scale 1:62,500. Nolf, Bruce and Taubeneck, W.H., 1963, Permo-Triassic stratigraphic revisions, Wallowa Mountains, northeastern Oregon [abs.]: Geological Society of America Special Paper 73, p. 92-93. 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. Beeson, J.H., Geology of the southern half of the Huntington quadrangle, Oregon: Eugene, University of Oregon, master's thesis, 77 p. Berry, N.J., 1956, Geology of the northeast quarter of the Huntington quadrangle, Oregon: Eugene, University of Oregon, master's thesis, 78 p. Weiss, P.L., Gualtieri,, J.L., Cannon, W.F., Tucher, E.T., McMahan, A.B., and Federspiel, F.E., 1976, Mineral resources of the Eagle Cap Wilderness and adjacent areas, Oregon: U.S. Geological Survey Bulletin 1385-E, 100 p. https://pubs.er.usgs.gov/publication/b1385E
NGMDB product	NGMDB product page for 16259
Counties	Baker - Grant - Malheur - Union - Wallowa

State

Oregon

Name

Volcanic and metavolcanic rocks

Geologic age

Late Triassic

Lithologic constituents

Major

Igneous > Volcanic (Flow)Keratophyre

Metamorphic > Hydrothermally-altered > Spilite

Minor

Sedimentary > Chemical > Chert (Bed)

Sedimentary > Clastic > Siltstone (Bed)

Sedimentary > Carbonate > Limestone (Bed)

Sedimentary > Clastic > Conglomerate (Bed)

Sedimentary > Clastic > Sandstone (Bed, Tuffaceous)coarse volcaniclastic sandstone, tuff, sandstone

Metamorphic > Metaigneous > MetavolcanicIncludes Late Triassic "andesitic and basaltic rocks" of Nolf and Taubeneck (1963), and the basaltic to rhyolitic metavolcanic rocks

Comments

Huntington Formation (OR073) is predominantly agglomerate, tuff, and flows intercalated with coarse volcaniclastic breccia and conglomerate. Also contains volcanic graywacke, volcanic arenite, water-laid tuff, volcanic siltstone, and minor limestone. Volcanic rocks range from basalt to rhyolite; andesite is the most common lithology. Fine-grained sedimentary rocks typically form bedded sequences ranging from a few meters to a few hundred meters thick. Includes dikes, sills, and irregular shallow intrusive bodies that are difficult to distinguish from extrusive rocks. The rocks have been metamorphosed to the zeolite and greenschist facies of regional metamorphism. Fossil ammonites and Halobia indicate marine depositioon and late Carnian to late middle Norian (late Triassic) age (OR073). A Lead-uranium age of 235 Ma for an intrusive tonalite in the Huntington Formation indicates that part of the unit is Middle Triassic or older (OR190). The unit is interpreted as a product of a Triassic volcanic arc that makes up the Olds Ferry terrane (OR089)..

Stratigraphic units

Huntington Formation (OR073)

References

Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000.

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., 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., 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

Brooks, H.C., 1979, Geologic map of the Huntington and part of the Olds Ferry quadrangles, Baker and Mlheur Counties, Oregon: Oregon Department of Geology and Mineral Industries Geologic Map Series, GMS-13, scale 1:62,500.

Nolf, Bruce and Taubeneck, W.H., 1963, Permo-Triassic stratigraphic revisions, Wallowa Mountains, northeastern Oregon [abs.]: Geological Society of America Special Paper 73, p. 92-93.

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.

Beeson, J.H., Geology of the southern half of the Huntington quadrangle, Oregon: Eugene, University of Oregon, master's thesis, 77 p.

Berry, N.J., 1956, Geology of the northeast quarter of the Huntington quadrangle, Oregon: Eugene, University of Oregon, master's thesis, 78 p.

Weiss, P.L., Gualtieri,, J.L., Cannon, W.F., Tucher, E.T., McMahan, A.B., and Federspiel, F.E., 1976, Mineral resources of the Eagle Cap Wilderness and adjacent areas, Oregon: U.S. Geological Survey Bulletin 1385-E, 100 p.

https://pubs.er.usgs.gov/publication/b1385E

NGMDB product

NGMDB product page for 16259

Counties

Baker - Grant - Malheur - Union - Wallowa