Biostratigraphy and depositional environment evolution of the Asmari Formation at the Shajabil anticline, Iran

In the present research, biostratigraphy and paleoecology of the Asmari Formation at the Shajabil anticline, northwest Yasuj in the Izeh zone are discussed. The Asmari Formation at the studied area is Rupelian-Chattian to Burdigalian in age. In the study, 18 genera and 29 species of benthic foraminifera have been identified. Besides, the following biozones which reflect Rupelian-Chattian to Burdigalian age are identified for the Asmari Formation: (1) Lepidocyclina-Operculina-Ditrupa; (2) Archaias asmaricus-Archaias hensoni-Miogypsinoides complanatus; (3) Peneroplis farsenensis_Elphidium sp.14-Miogypsina sp.; (4) Borelis melo-Borelis melo curdica. Relying on fossils, Coral and Corallinacea have been detected depositional environment. The paleo-ecological factors are identified for the Asmari Formation at the study area: water salinity, 34 to more than 50 psu; water depth of 90 to 0 m; water temperature of 14 A degrees C to more than 27 A degrees C in a subtropical to tropical environment, oligotrophoic to mesotrophic conditions.