Biostratigraphy and paleoecology of the Asmari Formation at Nil anticline area (north-east of Dehdasht)

The Asmari Formation at Nil anticline area has been studied in order to determine faunal assemblages، the age and the paleoecology. Paleontological and biostratigraphical studies led to the identification of 5 faunal assemblages. As a result، the age of the Asmari Formation in this section، with 291m thickness، is Rupelian/Chattian-Burdigalian. Extension of the large benthic foraminifera suggests that the Asmari Formation has been deposited in a shallow marine carbonate platform with tropical to subtropical and oligotrophy climatic condition. Based on faunal assemblage، the lower part of the Asmari Formation has been deposited in normal marine water conditions; while the upper part has been deposited in hypersaline waters. Diversity and the abundance of the benthic foraminifera، the rarity of coral debris and the absence of green algae show that the surface water temperature was low (below 20oc) during deposition of the Asmari Formation.