Micropaleontology and lithostratigraphy of the late Cretaceous deposits (Turonian -Campanian) based on planktonic foraminifera in the Lurestan, southwest of Khoramabad

In the present study, a stratigraphic section was selected on the Poshte-Jangal anticline in the southwestern part of Khorramabad to study the microbiostratigraphy of the Cretaceous sediments. This Section with a thickness 190 meters consists of invariable thin to Medium bedded limestones with Middle Turonian to Late Santonian age which were deposited in a continues sedimentation process. Both lower and the upper boundaries of this formation with The Surgah and Gurpi formations are conformable, respectively. In the present study of the Ilam Formation, 12 genera, 40 species and 4 biozones of the planktonic foraminifera were recognized. Based on the stratigraphic distribution of the introduced species and identified biozones the Middle Turonian to Late Santonian age is suggested for deposits of the Ilam Formation in this stratigraphic section.