Microbiostratigraphy and Sequencestratigraphy of the Gurpi Formation in central part of Lorestan zone, SW Iran

The Gurpi Formation constitutes the source rock for petroleum in the oil-rich South Iranian Basin.Gurpi Formations is well distributed along Zagros Foreland Basin particularly in the north west of the Zagros (Lorestan Province). For Microbiostratigraphy and Paleobathymetric studies of the Gurpi Formation in the central part of Lorestan two stratigraphic sections including Sultan and Amiran sections were selected. In this study, 48 foraminiferal species belonging to 25 genera were identified, and 7 biozones were recognized; Globotruncanita elevata Zone, Globotruncana ventricosa Zone, Radotruncana calcarata Zone, Globotruncanella havanensis Zone, Globotruncana aegyptiaca Zone, Gansserina gansseri Zone, Contusotruncana contusa Zone.Planktonic foraminiferal morphology was studied in order to assign paleobathymetry and the changes through sedimentation course of the Gurpi Formation.Three third-order sequences were identified,on the basis of deepening and shallowing patterns in the morphological changes and the distribution of the Gurpi Formation planktonic foraminifers and planktonic/ benthic ratio. Key words:Biostratigraphy, Planktic foraminifera, Gurpi Formation, Lorestan, Paleobathymetry