Biostratigraphy and Paleoecology of The Gurpi Formation in Marun Oil Field, Zagros Basin, SW Iran

The Gurpi Formation, one of the geological units of the Zagros Basin, stretches with in the Folded Zagros in the provinces of Khuzestan, Lorestan, and Fars, in southwest Iran. In total 525 samples were collected from the five wells to document the planktonic foraminifera. Overall, 47 species from 23 Planktonic foraminifera genera were recognized in this study. From a biochronostratigraphic point of view, 8 biozones were identified. Also, the age of Gurpi Formation in 21, 41, 43, 45, and 123 wells were determined based on the identified biozones of late Santonian to late Maastrichtian. Some important ecological factors including water level, salinity, and oxygen regime changes during the depositional courses of the formation were analyzed to examine the paleoecology.