Biostratigraphy of upper Cretaceous planktonic foraminifera in the south Zagros Basin (SW of Iran)

The Upper Cretaceous strata of the Zagros area is named Gurpi Formation. The selected stratigraphic section is attributed to a part of Folded–Thrust belt Zone of the Zagros, located 90 km southeast of Shiraz (SW of Iran) and is affected by the Sarvestan basement Fault within the Interior Fars region. The Gurpi Formation is extended approximately 28 m thick and is mainly formed of marly limestone, shale and argillaceous limestone, The biostratigraphy of the Gurpi Formation was investigated by collecting 121 samples from a selected stratigraphic section. Microscopic investigation represents the presence of 12 genera and 27 species of planktonic foraminifera. The stratigraphic distribution of investigated planktonic foraminifera represents eight biozones. The identified biozones in the Kharameh area from base to the top of Gurpi Formation consist of Helvetoglobotruncana helvetica Total Range Zone, Marginotruncana sigali Partial Range Zone, Dicarinella primitiva Interval Zone, Dicarinella concavata Interval Zone, Dicarinella asymetrica Total Range Zone, Globotruncanita elevata Partial Range Zone, Globotruncana ventricosa Interval Zone, Globotruncana aegyptiaca Total Range Zone. Based on the identified planktonic foraminifera and the described biozones, the age of the Gurpi Formation is assigned from middle Turonian to early Maastrichtian. [ABSTRACT FROM AUTHOR]