Microbiostratigraphy of Gurpi Formation at the southwestern flank of Khorram Abad anticline, Zagros Basin

The Gurpi formation at the southwestern flank of Khorram Abad anticline, Zagros Basin, consists of 182 m gray to green limestone and intercalation of silty limestone. In this area, Gurpi Formation overlies unconformably on the carbonate of Ilam Formation and is overlain by the turbiditic deposits of the Amiran Formation. The Study of planktonic foraminifera of the Gurpi Formation enables to find the most standard biozones defined in Tethyan domain. Six biozones were determined. Biozone I (Diacarinella asymetrica Total Range Zone) indicate Late Santonian, respectively. Biozonez II (Globotruncanita elevata Partial Range Zone), III (Globotruncana ventricosa Interval Zone), IIII (Radotruncana calcarata TaxonRange Zone), V (Globotruncanita stuartiformis Partial-Range Zone) and VI(Globotruncana aegyptiaca Interval Zone) suggest Early to Late Campanian. Biozone VII (Gansserina gansseri Interval Zone) belongs to upper part of Late Campanian to lower part of Early Masstrichtian.