Biozonation of the Gurpi Formatin in Banroushan Section (SW Ilam) based on Planktonic Foraminifera

The Gurpi Formation is located in the Zagros basin, SW Iran. This Formation in the Banroushan section, SW Ilam, consists of 225 m shale with interbeds of marl that has two formal Members including Seymareh (Lopha) and Emam Hassan. These Members are made up of limestone. The lower and upper boundaries of this Formation are continuos with the Ilam and Pabdeh Formations. In the present investigation, 46 planktonic species of 13 genera have been identified. The Gurpi Formation is divided into 10 biozone on the basis of planktonic foraminifera which are cosmopolitan and consist of: biozone1-Globotruncanita elevata Partial Range Zone; Biozone2- Globotruncana ventricosa Interval Zone; Biozone3- Globotruncanita calcarata Interval Zone; Biozone4- Globotruncanella havanensis Partial Range Zone; Biozone5- Globotruncana aegyptiaca Interval Zone; Biozone6- Gansserina gansseri Interval Zone; Biozone7- Contusotruncana contusa Interval Zone; Biozone8- Abathomphalus mayaroensis Interval Zone; Biozone9- Parasubbotina pseudobulloides Interval Zone; Biozone 10- Globanomalina pseudomenardii Interval Zone Based on planktonic foraminifera the Gurpi Formation in the study area was deposited during the Early Campanian to Paleocene times.