Determination of sea level change and paleosalinity of Sourgah Formation base on planktonic foraminifera at Sarkan oil field (well no.1) in Pol-e-Dokhtar district, Lorestan province

In this survey sea level change and paleosalinity in Sourgah Formation at Sarkan oil field have been investigated. The thickness of Sourgah Formation at mentioned well was measured 46 meters and have been consist of main lithological shales with intercalated of limestone and calcareous shale. Heed to study of planktonic foraminifera and oligosteginied have been determined late Middle Turonian-Late Santonian ages for studied section. Study of three morphotype groups such ESF, SWF (belong to shallow water) and DWF (belong to profound water) have been ratified majority of planktonic foraminifers fauna in mentioned formation belong to semi deep-profound area which were shown oligotrophic conditions. Also high quantity of P/B ratio was manifested deposition took place in semi deep- profound condition. Finally, based on Hedbergella and Whiteinellagenura, we are determined salinity change in this section.