Paleogene accretion of Upper Cretaceous oceanic limestone in Northern California

• Published in: Geology (Boulder) 1986-04, Vol.14 (4), p.350-353
• Main Authors: Sliter, William V, McLaughlin, Robert J, Keller, Gerta, Evitt, William R
• Format: Article
• Language: English
• Subjects: accretion; biostratigraphy; California; carbonate rocks; Cenozoic; Cretaceous; crust; Dinoflagellata; East Pacific; Eocene; Foraminifera; Franciscan Complex; Geophysics; Invertebrata; limestone; melange; Mesozoic; microfossils; North America; North American Pacific; North Pacific; Northeast Pacific; Northern California; oceanic crust; Pacific Ocean; Paleogene; paleolatitude; palynomorphs; planktonic taxa; plate collision; plate tectonics; Protista; sea-floor spreading; sedimentary rocks; solid Earth (tectonophysics); stratigraphy; tectonophysics; terranes; Tertiary; United States; Upper Cretaceous
• ISSN: 0091-7613; 1943-2682
• DOI: 10.1130/0091-7613(1986)14<350:PAOUCO>2.0.CO;2

Blocks of pelagic limestone, tectonically incorporated into coastal terrane melange, contain planktonic foraminifers of early Campanian to middle Maestrichtian age (82-69 Ma) typical of low latitudes between 20 degree N and 20 degree S. Carbonate concretions from the sheared terrigenous matrix of the melange yield temperate, middle-latitude planktonic foraminifers and dinoflagellates of middle to late Eocene age (49-41 Ma). The pelagic limestone and the basaltic substrate presumably formed on the eastern flank of the Pacific-Farallon spreading ridge in a low-latitude zone of high productivity and migrated northward on the Farallon plate until about 40 Ma when they initially encountered terrigenous turbidites north of lat. 30 degree N. Northward translation and final accretion were completed by about 25 Ma.