Late Triassic palynofloras of North America and their European correlatives

Abstract

Upper Triassic continental strata in the United States contain rare horizons which yield pollen assemblages. The Dockum Group and Chinle Formation of the American Southwest, as well as certain rock units within the Deep River, Richmond, and Taylorsville Basins of the Newark Group, contain palynomorphs which exhibit stratigraphically restricted ranges in Europe. The presence of Vallasporites ignacii, Camerosporites secatus and Ovalipollis ovalis in the Dockum Group, Chinle Formation, Cumnock Formation of the Deep River Basin, Vinita Formation of the Richmond Basin, and unnamed units in the Taylorsville Basin suggest that all these units are approximately contemporaneous. The occurrence of these and other stratigraphically diagnostic pollen taxa, particularly Patinasporites densus, further indicates a Middle to Late Karnian age for these units. The palynostratigraphy also implies that the Pekin Formation of the Deep River Basin is slightly older than the above mentioned units.