Upper Jurassic Radiolarian biostratigraphy of the lower member of the Taman Formation, east-central Mexico and of volcanopelagic strata overlying the Coast Range Ophiolite, Stanley Mountain, southern California Coast Ranges

Upper Jurassic Radiolaria from east-central Mexico and the southern California Coast Ranges are documented to determine the taxonomic, biostratigraphic, and paleogeographic significance of these assemblages. Samples collected from the lower member of the Taman Formation, east-central Mexico, contain lower Kimmeridgian to lower Tithonian Radiolaria (Zone 2, Subzone 2 beta to Zone 3, undifferentiated, sensu Pessagno et al.). Cherts and manganiferous limestones from volcanopelagic strata overlying the Coast Range Ophiolite at Stanley Mountain, California, yield upper Oxfordian to upper Tithonian Radiolaria (Zone 2, Subzone 2 gamma to Zone 4, Subzone 4 alpha). U/Pb geochronometric data from Stanley Mountain indicate ophiolite formation 166.0 {dollar}pm{dollar} m.y. Two hiatuses are recognized in this section based on radiolarian biostratigraphy. The Coast Range Ophiolite at Stanley Mountain is transitional with and overlain by the Great Valley Supergroup.; Detailed examination of radiolarian assemblages from the lower Taman Formation and southern California results in the establishment of 2 new families, 24 new genera, and 141 new species. The Family Leugeonidae Yang and Family Arcanicapsidae Takemura are revised and subdivided into subfamilies on the basis of test constructions. In total, 27 families, 100 genera, and 546 species of Upper Jurassic Radiolaria are documented. This extensive taxonomic research has led to refinement of North American radiolarian biostratigraphy in Oxfordian to Kimmeridgian strata. Numerous species are documented in North America for the first time in these assemblages, resulting in better correlation with radiolarian zonal schemes utilized throughout the circum-Pacific region.; Radiolarian assemblages described herein are applied to the radiolarian paleogeographic model presented by Pessagno and Blome. Faunas of the lower member of the Taman Formation possess Radiolaria typical of the Tethyan Realm, Northern Tethyan Province; radiolarian faunas of Stanley Mountain show a transition from the Tethyan Realm to the Southern Boreal Province, Boreal Realm. Paleomagnetic data from Stanley Mountain suggests that this remnant formed at 14 {dollar}pm{dollar} 7{dollar}spcirc{dollar} north or south of the paleoequator. Paleoceanographic influences on the radiolarian distributions are also considered in view of current knowledge of oceanographic effects on Recent Radiolaria.