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Siletzia

Basement domain in the Western Cordillera

Geologic information

Region Western Cordillera
Crust
Formation age: 60-50 Ma
Accretion
Type: Collisional
Age: 50 Ma
Notes Converted to continental arc. Some authors (Schmandt and Humphreys, 2011) suggest accretion at 55 Ma

Geographic extent

Benton, Clackamas, Clatsop, Columbia, Coos, Curry, Douglas, Josephine, Lane, Lincoln, Linn, Marion, Multnomah, Polk, Tillamook, Washington, Yamhill, Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Kitsap, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum

Bibliographic references

Babcock, R.S., Burmester, R.F., Engebretson, D.C., Warnock, A., and Clack, K.P., 1992, A rifted margin origin for the Crescent basalts and related rocks in the northern Coast Range volcanic province, Washington and British Columbia: Journal of Geophysical Research v. 97, no. B5, p. 6799–6821.Parsons, Tom, Wells, R.E., Fisher, M.A., Fleuh, E, and ten Brink, U.S., 1999, Three-dimensional velocity structure of Siletzia and other accreted terranes in the Cascadia forearc of Washington: Journal of Geophysical Research, v. 104, no. B8, p. 18,015–18,039.