Upper Eocene volcanic rocks

Rhyolite flows and some interbedded tuff beds in Cle Elum area, Kittitas County.
State Washington
Name Upper Eocene volcanic rocks
Geologic age Late-Middle Eocene
Lithologic constituents
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Flow, Dome, Pyroclastic-tuff)
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Volcaniclastic-volcanic breccia)
Metamorphic > Metasedimentary > Metaclastic > Argillite
Sedimentary > Clastic > Siltstone (Bed)
Sedimentary > Clastic > Mudstone > Shale (Bed)
Igneous > Volcanic > Mafic-volcanic > Andesite (Flow, Volcaniclastic-volcanic breccia)Possibly minor in rank but subordinate to rhyolite and basalt.
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Coal (Bed)Rare occurrence in Naches Formation; may or may not occur in this unit.
Comments Two stratigraphic units in WAEv1r, "Kachess rhyolite" and "Rhyolite in the Guye", were listed in Huntting and others, 1961, with a footnote referencing a 1906 USGS geologic atlas folio by G. O. Smith and F. C. Calkins; none of the referenced literature in this database names any outcrops similarly. Furthermore, any rhyolite within the Guye Formation is geographically more likely to occur in either WAEPKc (which includes the Guye Formation) or WAlTv (which includes the Mt. Catherine rhyolite adjacent to the Guye Formation). The Kachess rhyolite must be associated with Kachess Lake just north of the unit.
Stratigraphic units Naches Formation (in part)

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.

Dragovich, J.D., Logan, R.L., Schasse, H.W., Walsh, T.J., Lingley, W.S., Jr., Norman, D.K., Gerstel, W.J., Lapen, T.J., Schuster, J.E., Meyers, K.D., 2002, Geologic Map of Washington-Northwest Quadrant: Washington Division of Geology and Earth Resources Geologic Map GM-50, scale 1:250,000.

Tabor, R.W., Frizzell, V.A., Jr., Booth, D.B.., Waitt, R.B., 2000, Geologic Map of the Snoqualmie Pass 30 x 60 Minute Quadrangle, Washington: U. S. Geological Survey Geologic Investigations Series I-2538, 57 p., 1 pl.

NGMDB product
Counties Kittitas