Document Type : Original Research Paper


1 Islamic Azad University (IAU), Science and Research Campus , Tehran, Iran.

2 Exploration Management of N.I.O.C., Tehran, Iran.

3 Geological Survey of Iran, Tehran, Iran.


In order to study Biostratigraphy of Cenomanian – Late Campanian deposits (upper part of Sarvak Fm.,Ilam Fm. and lower part of Gurpi Fm.), kuhe Assaluyeh stratigraphic section selected. Sediments of this interval consist of limestone, argillaceous limestone and marl with thickness of 162 m. In this section Ilam Fm. in age of Santonian overlies Sarvak Fm. disconformably and is underlain by Gurpi Fm. conformably. By micropaleontological study on 55 thin sections, 5 genus and 9 species of planktonic and 16 genus and 13 species of benthic foraminifers were identified. Among distinguished foraminifers, Rotaliidae family forms were studied carefully and revised. It should be mentioned that, 5 genus and 6 species of benthic foraminifers (Rotaliid forms) were recognized in Iran for the first time (in Assaluyeh section) which consist of: Rotorbinella mesogeensis,Rotorbinella campaniola,Iberorotalia reicheli,Calcarinella schaubi, Pararotalia tuberculifera and Pyrenerotalia longifolia. Santonian age was determined for Ilam Fm. by identified foraminifers. In studied section, stratigraphy development of benthic foraminifers was compared by Martinez Biozones Martinez (2007). This biozones were presented on the base of Rotaliid forms for Pyrenees area in Spain. By this comparison, four biostratigraphy zones for upper part of Sarvak and Ilam Fm. are suggested.


  Adams, T. D., Khalili, M. & Khosravi Said, A., 1967- Stratigraphic Significance of some oligosteginid assemblages from Lurestan Province, north west  Iran.
Adams, T. D., 1964 - A guide to the study of cretaceous (Albian- Masstrichtian)  planktonic forminifera in thin section, N.I.O.C, Report No. 1080.
Berthou, P. Y., 1983- Updated Stratigraphic distribution of the main Benthic  Foraminifera ftom the middle and Upper Cretaceous of the western Portuguese basin. Bentho, s 83, Second International Symposium on  Benthic Foraminifera (Pau, 1983), pp. 45-54.
Caron, M., 1985- Cretaceous Planktic Foraminiferal, In, H.M. Bollii, J.B.  Saunder and K.perch- Nielsen (eds) Plankton Strargrapgy. Cambtidhe  university press.
Martinez, C. B., 2007- Foraminiferos Rotalidos Del Cretacico  Superior De la Cuenca Pirenaica. Barcelona, Department de Geologia   Unitat de Paleontologia Tesis Doctoral.
Calonge, A., Cause, E., Bernaus, J. M. & Aguilar, M., 2002- Praealveolina (Foraminifera) species: a tool to date Cenomanian platform sediments.
Gräfe, K. U., 2005- Late Cretaceous benthic foraminifers from the  Basque- Cantabrian Basin, Northern Spain. Journal of Iberian Geology
James, G. A. & Wynd, J. G., 1965- Stratigraphy nomenclature of the Iranian oil consortium agreement area, report No. 1027.
Kalantari, A., 1987- Lithostratigraphy and facies microscopy Zagros, Labrator  Geology, Sample. 12, N.I.O.C.
Khosrotehrani, Kh., Fonooni, B.,1737- New founds in Microbiostratigraphy of   Sarvak Formation in Fars and Khoozestan areas, Scientific Quarterly  Journal Geosciences, Vol. 3, No. 11.
Loeblich, A. R. J. and Tappan, H., 1988- Foraminiferal genera and their   Classification, Van Nostrand Reinhold Company, New York.2, Volumes   97, Pls. 847. New York.
Premoli. S. & verga, D., 2004 - Practical manual of Cretaceous planktonic  foraminifera.
Postuma, J. A., 1971- Manual of Planktonic Foraminiferal, Elsever, 420 p.
Posobina, V. M. & Kseneva, T. G., 2005- Upper Cretaceous Zonal Stratigraphy   of the West Siberian plain based on foraminifera. Cretaceous research.
Parvanenejad Shirazi, M., 2001- Microstratigraphy of Cretaceous Sediments in   Zagros area (interior Fars) trough Shiraz-Dehbid axial with special   observation on Algae, Ph. D thesis, Shahid Beheshti University.
Rose Petrizzo, M., 2000- Upper Turonian-Lower Campanian Planktonic Foraminifera from Southern mid- high latitudes (Exmouth Plateau, NW   Australia): biostratigraphy and taxonomic notes. Cretaceous research.
Sampo, M., 1969- Microfacies and mirofossils of the Zagros area South   Western Iran (From Pre- Permian to Miocene).
Sartorio,  D. & Venturini, S., 1988- Southern Thethys biofacies, ayip,   Stratigraphic department.
Vaziri Mogaddam, H., 2002- Biosrtatigraphic Study of the Ilam and Gurpi   Formations Based on Planktonic Foraminifera in SE of Shiraz, Iran. Journal   of Sciences, Islamic Republic of Iran.
Wynd, J. G., 1965- Biofacies of the Iranian oil Consortium agreement area.    Report No. 1082.