Biostratigraphy of Calcareous Nannofossils of Gurpi Formation in North Gachsaran

Nannofossils are good for biostratigraphy, since they are abundant, planktonic, rapidly evolving and largely cosmopolitan especially in the Late Cretaceous. With respect to this reality and due to the lack of any precise paleontological study, the nannofossils of Gourpi Formation were investigated in the north of Gachsaran. This formation consists of marl and clay limestone. In this study, for the first time, 23 genera and 43 species of nannofossils were identified. Based on the obtained nannofossils, the study section is Late Santonian to Late Maastrichtian in age corresponding to CC16-CC26.