Stratigraphy of the Permian calcareous deposits (Ruteh and Nesen Formations) based on Foraminifera in Pir- Eshagh area, South of Joulfa, NW Iran

The thickness of the Permian sequence in Pir- Eshagh Stratigraphical section were measured about 1400 meters, which the lower 100 meters, belong to Dorud formation and the thickness of Ruteh and Nesen formations 1100 meters, and 200 meters respectively. The lower boundary of the sequence lies on the volcanic rocks of Devonian (Andesite- Dacite), nonconformaly and the upper ones into the yellowish laminated limeston of the Elika formation continously of the early and middle Triassic. In order to study the above mentioned sequence, we systematically selected 220 thin sections from the lower bound up to the upper bound based on lithological changes in a perpendicular direction.19 types and 21 genera of 10 families of non- Fusulinid Foraminifers, and 10 types and 5 genera of Fusulinid Foraminifers’ Families- including Ozawainellidae, Schubertellida, Schwagerinidae and Stafellidae- were recognized in the thin sections. According to Foraminifers’ transmittancy, there were 3 Assemblage Biozones and based on Stratigraphical conditions and fossilised contents, we could define the ages of Asselian- Sakmarian, Morgabian- Midian and Dzhulfian for Dorud, Ruteh and Nesen formations, respectively.