Biostratigraphy of the Pabdeh Formation in the Parsi Oil Field (Dezful embayment, South-West Iran)

In order to study biostratigraphy and the determination of biozonationes in the Pabdeh Formation based on the new planktonic foraminifera biozonationes in the Thethys region, one subsurface section in well 1 of Parsi Oil Field was selected in the southern Dezful Embayment. Based on this study, biostratigraphic study of 320 thin section from well 1 of Parsi Oil Field has been carried out. The Pabdeh Formation with a thickness of 404 m consists mainly of shale, marl, argilaceous limestone and cherty limestone.The lower boundary of the Pabdeh Formation with the Gurpi Formation is unconformable and the upper boundary with the Asmari Formation is conformable. Biostratigraphic studies led to the recognition of 25 genera and 75 species of planktonic foraminifera and then 19 biozones equivalent to new biozone of Wade et al. (2011) in the Thethys region. These identified biozones include 3 biozones in the Paleocene, 11 biozones in the Eocene and 5 biozones in the Oligocene in the studied section in well 1 of Parsi Oil Field and are well correlated with some biozones in the Tethys region. Based on the identified biozones and fossil contents, the age of the Pabdeh Formation is Middle Paleocene (Selandian) – Late Oligocene (Chattian). Defined biozones are compared with the other sections presented in the Izeh Zone (Tange Hatti, Tange Pabdeh and Chahardeh)