Palynostratigraphy of the Upper Cretaceous deposits (K3) in the Central Alborz Basin (Dare-zar section)

To investigate the Upper Cretaceous deposits in the Central Alborz Basin, a 100-meter thick stratigraphic section was chosen in the southwest of Dareh Zar village in the east of Tehran. In this study, a total of 75 species, belonging to 44 dinocyst genera, and 10 species from seven spore genera were identified. Consequently, two biozones—Dinogymnium acuminatum and Carpatella cornuta—have been determined. The association of the Dinogymnium acuminatum biozone with index planktonic foraminifers such as Contusotruncana contusa, Globotruncana arca, and Globotruncana ventricosa at the base of the studied section confirms the Late Cretaceous age. Furthermore, the presence and abundance of the Carpatella cornuta biozone in sample 44 indicate the beginning of the Paleocene. The presence of this biozone with typical dinocysts such as Damassadinium californicum, Thalassiphora delicate, and Tectatodinium sp. suggests the upper Paleocene age range for the end of the stratigraphic section. The presented biozones based on dinocysts are consistent with those in eastern Europe and northwestern Tethys, indicating a marine connection between these regions in the Late Cretaceous.