State | Oregon |
---|---|
Name | Tillamook Volcanics |
Geologic age | Middle Eocene to Late Eocene |
Lithologic constituents |
Major
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Pyroclastic-tuff, Volcaniclastic-volcanic breccia)
Minor
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Clastic > Siltstone (Bed)
Sedimentary > Clastic > Conglomerate (Bed)
Incidental
Igneous > Volcanic > Mafic-volcanic > Basaltic-andesite (Flow, Pyroclastic-tuff, Volcaniclastic-volcanic breccia)
Igneous > Volcanic > Felsic-volcanic > Dacite (Flow, Pyroclastic-tuff, Volcaniclastic-volcanic breccia)
|
References | Walker, G.W. and MacLeod, N.S., 1991, Geologic map of Oregon: U.S. Geological Survey, scale 1:500,000.Magill, J., Cox, A., and Duncan, R., 1981, Ttillamook volcanic series-further evidence for tectonic rotation of the Oregon Coast Range: Journal of Geophysical Research, v. 86, p. 2953-2970.Wells, R.E., Niem, A.R., MacLeod, N.S., Snavely P.D., Jr., and Niem, W.A., 1983, Preliminary geologic map of the west half of the Vancouver (Washington-Oregon) 1ø by 2ø quadrangle: U.S. Geological Survey Open-File Report 83-591, scale 1:250,000.https://pubs.er.usgs.gov/publication/ofr83591 |
NGMDB product | |
Counties | Clackamas - Clatsop - Columbia - Douglas - Grant - Multnomah - Tillamook - Washington - Yamhill |