Nannostratigraphy and the study of Foraminifera Planktonic of Ilam Formation, Southwest Iran (Shiraz)

The Ilam Formation in the north east of Shiraz was studied based on calcareous nannofossils and planktonic foraminifera. This formation consists of sedimentary dark limestone. In this study, for the first time 18 genera and 26 species of nannofossils were identified. According to the stratigraphic development of calcareous nannoplankton, interval time is suggested from late Coniacian-early Santonian to Early early Campanian corresponding to Micula decussata zone,Reinhardtites anthophorus zone, Lucianorhabdus cayeuxii zone and Calculites obscurus zone. Calcareous nannofossils in this study were investigated along with planktonic foraminifera. Based on the information obtained from planktonic foraminifera, the age of the section is late Coniacian-early Santonian to early Campanian corresponding to Dicarinella concavata zone,Dicarinella asymetrica zone and Globotruncanita elevata zone. The presence of index species of calcareous nannofossils indicates that the Ilam Formation deposited in the low latitudes and warm ocean.