Biostratigraphy and lithostratigraphy of Tarbur Formation (Upper Cretaceous) in Hossein Abad section, Zagros basin (SW of Iran)

Abstract

The Tarbur Formation is a Reef carbonate lithostratigraphic unit that outcrops in the Zagros basin. To study biostratigraphy and lithostratigraphy of Tarbur Formation in Zagros basin, Hossein Abad Section was selected. In this section, the Tarbur Formation lies unconformably on the Pre-Campanian radiolarite beds and the Sachun Formation overlies the Tarbur Formation uncorformably. 39 foraminifera species belonging to 27 genera were identified from the Hossein Abad section in the Tarbur Formation. Orbitoides media, Orbitoides cf. concavatus, Orbitoides apiculata, Orbitoides sp., Omphalocyclus macroporus, Omphalocyclus sp., Pseudomphalocyclus blumenthalis, Lepidorbitoides sp., Antalyna korayi, Dicyclina shlumbergeri, Archaecyclus midorietalis and Goupillaudina shirazensis are the most significant foraminifers. Based on faunal assemblages, three biozones were proposed: Archaecyclus midorietalis range zone (late Campanian), Orbitoides—Goupillaudina assemblage Zone (early Maastrichtian and Antalyna korayi range subzone (late Maastrichtian). Foraminiferal assemblage of the Tarbur Formation supports late Campanian to late Maastrichtian age in section of Hossien Abad.