Eocene volcanic rocks (WAEOv;0)

State	Washington
Name	Eocene volcanic rocks
Geologic age	Eocene
Lithologic constituents	Major Igneous > Volcanic > Mafic-volcanic > Andesite (Flow, Volcaniclastic-volcanic breccia, Pyroclastic-tuff) Minor Igneous > Volcanic > Felsic-volcanic > Dacite (Flow, Volcaniclastic-volcanic breccia, Pyroclastic-tuff) Incidental Sedimentary > Clastic > Siltstone (Bed) Sedimentary > Clastic > Sandstone (Bed, Tuffaceous)Feldspathic to volcaniclastic to tuffaceous. Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Volcaniclastic-volcanic breccia, Pyroclastic-tuff)Possibly breccia and tuff as well. Possibly minor in rank. Sedimentary > Clastic > Conglomerate (Bed) Metamorphic > Metasedimentary > Metaclastic > Argillite
Comments	Luedke, 1998, indicates that some of this unit is basaltic; Tabor and others, 1993, reports that this unit is mostly andesite flows, tuff, porphyry and breccia with minor dacite, dacite breccia, and basalt, and minor volcaniclastic sandstone, conglomerate, and siltstone; Smith, 1993, reports that this unit is all Eocene andesite. Dragovich and others, 2002, reports that this unit is mostly andesite but includes basalt and dacite flow, breccia, and tuff with interbedded sandstone, conglomerate, and argillite.
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. 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 Tabor, R.W., Frizzell, V.A.,Jr., Booth, D.B., Waitt, R.B., Whetten, J.T., Zartman, R.E., 1993, Geologic Map of the Skykomish River 30- by 60-Minute Quadrangle, Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1963, scale 1:100,000. Smith, J.G., 1993, Geologic Map of Upper Eocene to Holocene Volcanic and Related Rocks in the Cascade Range, Washington; U. S. Geological Survey Miscellaneous Investigations Series Map I-2005, scale 1:500,000. 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.
NGMDB product	NGMDB product page for 30777
Counties	King - Lewis - Snohomish

State

Washington

Name

Eocene volcanic rocks

Geologic age

Eocene

Lithologic constituents

Major

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

Minor

Igneous > Volcanic > Felsic-volcanic > Dacite (Flow, Volcaniclastic-volcanic breccia, Pyroclastic-tuff)

Incidental

Sedimentary > Clastic > Siltstone (Bed)

Sedimentary > Clastic > Sandstone (Bed, Tuffaceous)Feldspathic to volcaniclastic to tuffaceous.

Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Volcaniclastic-volcanic breccia, Pyroclastic-tuff)Possibly breccia and tuff as well. Possibly minor in rank.

Sedimentary > Clastic > Conglomerate (Bed)

Metamorphic > Metasedimentary > Metaclastic > Argillite

Comments

Luedke, 1998, indicates that some of this unit is basaltic; Tabor and others, 1993, reports that this unit is mostly andesite flows, tuff, porphyry and breccia with minor dacite, dacite breccia, and basalt, and minor volcaniclastic sandstone, conglomerate, and siltstone; Smith, 1993, reports that this unit is all Eocene andesite. Dragovich and others, 2002, reports that this unit is mostly andesite but includes basalt and dacite flow, breccia, and tuff with interbedded sandstone, conglomerate, and argillite.

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.

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

Tabor, R.W., Frizzell, V.A.,Jr., Booth, D.B., Waitt, R.B., Whetten, J.T., Zartman, R.E., 1993, Geologic Map of the Skykomish River 30- by 60-Minute Quadrangle, Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1963, scale 1:100,000.

Smith, J.G., 1993, Geologic Map of Upper Eocene to Holocene Volcanic and Related Rocks in the Cascade Range, Washington; U. S. Geological Survey Miscellaneous Investigations Series Map I-2005, scale 1:500,000.

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.

NGMDB product

NGMDB product page for 30777

Counties

King - Lewis - Snohomish