Pliocene-Pleistocene volcanic rocks

Light-gray andesite, andesite porphyry, and open-textured basalt flows with minor associated mudflows and breccia. Includes restricted areas of valley flow basalt in Snake River Canyon in southeastern Washington and in Spokane area.
State Washington
Name Pliocene-Pleistocene volcanic rocks
Geologic age Mostly Pleistocene
Lithologic constituents
Major
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow, Volcaniclastic-volcanic breccia)
Minor
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Comments Referenced literature does not mention associated mudflows.
Stratigraphic units Boring lavas; Intercanyon lava; Tieton andesite
References

Huntting, M.T., Bennett, W.A.G., Livingston, V.E.Jr., and Moen, W.S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000.

Walsh, T.J., Korosec, M.A., Phillips, W.M., Logan, R.T., Schasse, H.W., 1987, Geologic Map of Washington-Southwest Quadrant: Washington Division of Geology and Earth Resources, Geologic Map GM-34, scale 1:250,000.

Warren, W.C., 1941, Relation of the Yakima Basalt to the Keechelus Andesite Series: The Journal of Geology, v. 49, p. 795-814.

Luedke, R.G., Smith, R.L., Russell-Robinson, S.L., 1983, Map showing distribution, composition, and age of late Cenozoic volcanoes and volcanic rocks of the Cascade Range and vicinity, northwestern United States: U. S. Geological Survey Miscellaneous Investigations Series Map I-1507, scale 1:500,000.

Phillips, W.M., 1987, Geologic Map of the Vancouver Quadrangle, Washington and Oregon: Washington Division of Geology and Earth Resources Open File Report 87-10, scale 1:100,000.

NGMDB product
Counties Asotin - Clark - Columbia - Franklin - Garfield - Lewis - Skamania - Spokane - Whitman - Yakima