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Franciscan

Basement domain in the Western Cordillera

Geologic information

Region Western Cordillera
Alternate names Franciscan equivalents
Crust
Formation age: 165-50 Ma
Accretion
Type: Underthrusting
Age: 165-50 Ma
Notes In NW CA, accreted rocks as young as 15 Ma (McLaughlin and others, 1982)

Geographic extent

Alameda, Colusa, Contra Costa, Glenn, Humboldt, Imperial, Kings, Lake, Los Angeles, Marin, Mendocino, Merced, Napa, Orange, Riverside, San Benito, San Bernardino, San Diego, San Francisco, San Joaquin, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Solano, Sonoma, Stanislaus, Tehama, Trinity, Ventura, Yolo, Clackamas, Douglas, Gilliam, Hood River, Josephine, Lane, Linn, Marion, Morrow, Multnomah, Sherman, Adams, Benton, Chelan, Douglas, Franklin, Grant, Island, King, Kitsap, Kittitas, Klickitat, Lewis, Mason, Okanogan, Pierce, San Juan, Skagit, Skamania, Snohomish, Walla Walla, Whatcom, Yakima

Bibliographic references

Saleeby, J.B., 1982, Polygenetic ophiolite belt of the California Sierra Nevada–Geochronological and tectonostratigraphic development: Journal of Geophysical Research, v. 87, p. 1803–1824.Ernst, W.G., 2011, Accretion of the Franciscan complex attending Jurassic-Cretaceous geotectonic development of northern and central California: Geological Society of America Bulletin, v. 123, p. 1667–1678.Snow, C.A., Wakabayashi, J., Ernst, W.G., and Wooden, J.L., 2010, Detrital zircon evidence for progressive underthrusting in Franciscan metagraywackes, west-central California: Geological Society of America Bulletin, v. 122, p. 282–291.Wakabayashi, John, and Dumitru, T.A., 2007, 40Ar/39Ar ages from coherent, high-pressure metamorphic rocks of the Franciscan complex, California—Revisiting the timing of metamorphism of the world’s type subduction complex: International Geology Review, v. 49, p. 873–906.