New rhynchonellid brachiopod genus from Tithonian (Upper Jurassic) cold seep deposits of California and its paleoenvironmental setting

Abstract

A new brachiopod genus Cooperrhynchia is described for the species originally designated “Rhynchonella” schucherti Stanton, 1895, from the so-called Knoxville beds of northern California. A lectotype is selected for Cooperrhynchia schucherti (Stanton). An isolated carbonate lens within deep-water turbidites of the Great Valley Group (Jurassic–Cretaceous) yielded the brachiopod fossils near the town of Paskenta, western Sacramento Valley. The associated bivalve fauna indicates a mid late Tithonian age for the locality. Mollusks and the rhynchonellids Cooperrhynchia and Peregrinella are known from several scattered limestone lenses within Great Valley strata; collectively, these faunas and carbonate patches represent cold seep-associations that developed in forearc basins along the tectonically active northeast Pacific convergent margin during the late Mesozoic.