Upper Eocene volcanic rocks (WAEOv1b;0)

State	Washington
Name	Upper Eocene volcanic rocks
Geologic age	Late Eocene to Oligocene
Lithologic constituents	Major Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow) Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Pyroclastic-tuff, Volcaniclastic-volcanic breccia) Incidental Igneous > Volcanic > Felsic-volcanic > Dacite (Flow) Igneous > Volcanic > Mafic-volcanic > Andesite (Flow) Sedimentary > Clastic (Tuffaceous)Water-laid tuff"" of Robert 1958. Sedimentary > Clastic > Sandstone (Bed) Sedimentary > Clastic > Mudstone > Shale (Bed) Sedimentary > Clastic > Conglomerate (Bed) Igneous > Volcanic > Felsic-volcanic > Rhyolite (Flow) Sedimentary > Clastic > Siltstone (Bed)
Comments	Luedke, 1998, indicates that this unit has a large volume of andesite as compared to basalt. Walsh and others, 1987, indicate that this unit is almost entirely basaltic andesite flows of Oligocene to Eocene age with minor andesite, dacite, and basalt flows, and thin interbeds of shale, tuff, and volcanic sandstone. Hatchet Mountain formation consists of a base of basaltic conglomerate, sandstone, and water-laid tuff, underlying 2750 feet of basaltic and andesitic lava flows, flow breccia, pyroclastic,and tuffaceous sedimentary rocks. Increase in thickness to south and east as Cowlitz changes from marine to nonmarine (Roberts, 1958). Roberts, 1958, also suggests that Goble volcanic series includes Hatchet Mountain and parts of the Cowlitz and Toutle Formations (see WAOlv) as opposed to being contained within the Cowlitz formation. Phillips, 1987, maps the portion of the unit south of the Lewis River as basaltic-andesite and basalt flows with interbedded tuff and basaltic sandstone and conglomerate. North of the Lewis River are basaltic-andesite lava flows and flow breccia of the Goble Volcanics with interbedded sedimentary rocks. Small polygon in northern Ferry County tagged as WAEv1b in digital coverage is really WATas in original map.
Stratigraphic units	Cowlitz formation (in part: Goble volcanic member, Pe Ell volcanic member); Hatchet Mountain formation; Teanaway basalt
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. Luedke, Robert G., 1998, Maps showing distribution, composition, and age of Early and Middle Cenozoic volcanic centers in Oregon and Washington: U.S. Geological Survey Miscellaneous Investigations Series Map I-2291-D, scale 1:1,000,000. https://pubs.er.usgs.gov/publication/i2291D Foster, R.J., 1960, Tertiary Geology of a Portion of the Central Cascade Mountains, Washington: Geological Society of America Bulletin v. 71, no. 2, p. 99-126. Roberts, A.E., 1958, Geology and Coal Resources of the Toledo-Castle Rock District, Cowlitz and Lewis Counties, Washington: U. S. Geological Survey Bulletin 1062, 71 p, 6 pls. Tabor, R.W., Waitt, R.B.,Jr., Frizzell, V.A.,Jr., Swanson, D.A., Byerly, G.R., Bentley, R.D., 1982, Geologic Map of the Wanatchee 1:100,000 Quadrangle, Central Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1311, scale 1:100,000. 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	NGMDB product page for 30777
Counties	Clark - Cowlitz - Kittitas - Lewis - Pacific - Skamania

State

Washington

Name

Upper Eocene volcanic rocks

Geologic age

Late Eocene to Oligocene

Lithologic constituents

Major

Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow)

Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Pyroclastic-tuff, Volcaniclastic-volcanic breccia)

Incidental

Igneous > Volcanic > Felsic-volcanic > Dacite (Flow)

Igneous > Volcanic > Mafic-volcanic > Andesite (Flow)

Sedimentary > Clastic (Tuffaceous)Water-laid tuff"" of Robert 1958.

Sedimentary > Clastic > Sandstone (Bed)

Sedimentary > Clastic > Mudstone > Shale (Bed)

Sedimentary > Clastic > Conglomerate (Bed)

Igneous > Volcanic > Felsic-volcanic > Rhyolite (Flow)

Sedimentary > Clastic > Siltstone (Bed)

Comments

Luedke, 1998, indicates that this unit has a large volume of andesite as compared to basalt. Walsh and others, 1987, indicate that this unit is almost entirely basaltic andesite flows of Oligocene to Eocene age with minor andesite, dacite, and basalt flows, and thin interbeds of shale, tuff, and volcanic sandstone. Hatchet Mountain formation consists of a base of basaltic conglomerate, sandstone, and water-laid tuff, underlying 2750 feet of basaltic and andesitic lava flows, flow breccia, pyroclastic,and tuffaceous sedimentary rocks. Increase in thickness to south and east as Cowlitz changes from marine to nonmarine (Roberts, 1958). Roberts, 1958, also suggests that Goble volcanic series includes Hatchet Mountain and parts of the Cowlitz and Toutle Formations (see WAOlv) as opposed to being contained within the Cowlitz formation. Phillips, 1987, maps the portion of the unit south of the Lewis River as basaltic-andesite and basalt flows with interbedded tuff and basaltic sandstone and conglomerate. North of the Lewis River are basaltic-andesite lava flows and flow breccia of the Goble Volcanics with interbedded sedimentary rocks. Small polygon in northern Ferry County tagged as WAEv1b in digital coverage is really WATas in original map.

Stratigraphic units

Cowlitz formation (in part: Goble volcanic member, Pe Ell volcanic member); Hatchet Mountain formation; Teanaway basalt

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.

Luedke, Robert G., 1998, Maps showing distribution, composition, and age of Early and Middle Cenozoic volcanic centers in Oregon and Washington: U.S. Geological Survey Miscellaneous Investigations Series Map I-2291-D, scale 1:1,000,000.

https://pubs.er.usgs.gov/publication/i2291D

Foster, R.J., 1960, Tertiary Geology of a Portion of the Central Cascade Mountains, Washington: Geological Society of America Bulletin v. 71, no. 2, p. 99-126.

Roberts, A.E., 1958, Geology and Coal Resources of the Toledo-Castle Rock District, Cowlitz and Lewis Counties, Washington: U. S. Geological Survey Bulletin 1062, 71 p, 6 pls.

Tabor, R.W., Waitt, R.B.,Jr., Frizzell, V.A.,Jr., Swanson, D.A., Byerly, G.R., Bentley, R.D., 1982, Geologic Map of the Wanatchee 1:100,000 Quadrangle, Central Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1311, scale 1:100,000.

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

NGMDB product page for 30777

Counties

Clark - Cowlitz - Kittitas - Lewis - Pacific - Skamania