Gurpi Formations is well distributed along Zagros Foreland Basin particularly in the north west of the Zagros (Lurestan Province). For Microbiostratigraphy and Paleobathymetric studies of the Gurpi Formation in the central part of Lurestan two stratigraphic sections including Soltan and Amiran sections were selected. In this study, 48 foraminiferal species belonging to 25 genera were identified, and 7 biozones were recognized; Globotruncanita elevata Taxon Range Zone, Globotruncana ventricosa Interval Zone, Radotruncana calcarata Taxon Range Zone, Globotruncanella havanensis Partial Range Zone, Globotruncana aegyptiaca Interval Zone, Gansserina gansseri Interval Zone, Contusotruncana contusa Interval Zone. Planktonic foraminiferal morphology was studied in order to assign paleobathymetry and the sequences stratigraphic 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 planktic/benthic (P/B).Key words:Biostratigraphy, Planktic foraminifera, Gurpi Formation, Lorestan, Paleobathymetry پرونده مقاله

The benthic and planktonic foraminiferal contents of the Bangestan Group (Sarvak, Surgah and Ilam formations) in the Sepid Kuh anticline in the Lorestan Zone, W Iran, were studied. Bangestan Group consists of limestone, argillaceous limestone, dolomitic limestone and marl with thickness of 5400 m. In this section Bangestan Group overlies Garu Formation disconformably and its upper boundary is not exposed. By micropaleontological study on 176 thin sections, 8 genus and 34 species planktonic foraminifera were identified. 400 m of Sarvak Formation has very little fossil diversity that does not indicate a certain age. For this reason, this interval was called the indeterminate zone, which due to its stratigraphic position, is probably of Cenomanian age. Based on the biostratigraphical range of planktonic foraminifera distinguished, four biozones can be identified: Helvetoglobotruncana helvetica Total Rang Zone (Early- Middle Turonian), Marginotruncana schneegansi partial Range Zone (late Turonian), Diacarinella concavata Interval Zone (Coniacian), and Diacarinella asymetrica Total Zone (Santonian). پرونده مقاله