Biostratigraphy of E5 unit of Karaj Formation in North of Ashtian, Central Iran

Karaj Formation overlies unconformably on the Upper Cretaceous carbonate sediments and is overlain by the Oligocene molassic sediments of the Lower Red Formation, in the Ashtian area, Central Iran. In this area, Karaj Formation includes of volcanic (andesite and basalt), pyroclastics rocks and intercalations of carbonate and sandstone. It is divided to five lithozones that includ E1-E5 units. Only E5 unit contains various larger benthic and small foraminifera. In order to biostratigraphy of E5, one stratigraphic section was surveyed and sampled in north of Ashtian. In this section, thickness of E5 unit is 610 m. Study of this section led to identification 10 genera and16 species. The age of the E5 unit in the studied section is assigned to the Middle Eocene (Lutetian). E5 unit is equivalent with Upper TuffMember at type section of Karaj Formation in west of Challus valley, Alborz Basin, and upper part of Pabdeh and Jahrum Formations in Zagros Basin.