Biostratigraphy of Gurpi Formation in Anaran anticline (Lurestan Province) based on calcareous nannofossils

The Gurpi Formation at Anaran Anticline in SE of Lurestan province.consists of 269.5 meters of marl with intercalation of limy marl; two formal members of Seymareh limestone and Emam-Hasan argillaceous limestone are also exposed. Studies reveal presence of 70 species belonging to 38 genera of calcareous nannofossils based on which 8 global biozones were differentiated. Consequently, the Gurpi Formation was attributed to middle Campanian through Paleocene. There is a distinct hiatus in Cretaceous-Paleogene boundary based on paleontological evidence, as deduced from the absence of nannofossil biozones NP1-NP4. It seems that the reactivation of Anaran linement as paleohigh caused facies changes and hiatus in Gurpi Formation in SE of Lurestan province.