New approach on biostratigraphy of Permian deposits of Jamal formation in Bagh Vang section, Shirgesht area (central Iran)

Bagh Vang Section is located at about 45 km to the Northwest of Tabas and South of Shirgesht areas. In Bagh Vang Section, the Permian deposits of the Jamal Formation with a thickness of 270 m are underlain by the Sardar Formation disconformably. The formation is also transitionally and conformably overlain by Lower Triassic deposits of Sorkh Shale Formation. A total of 124 rock samples have been systematically obtained from various layers of Bagh Vang Section for biostratigraphic study. Forty one genera and 48 species of foraminifera; 10 genera and 12 species of algae have also been determined through this study. According to the biostratigraphic study, some index fossils of Fusulinidae have been recorded and the following assemblage zones have been selected that are equivalent to international biozones (Leven, 1975; Ishii, 1975): Paradunbarula – Geinitzina Assemblage Zone (Murghabian), Dagmarita – Paraglobivalvulina Assemblage Zone (Djulfian), Colaniella – Reichelina Assemblage Zone (Changhsingien). Further, geochronology of Member 1 and Member 2 of the Jamal Formation (Bagh Vang Member) is attributed to Early Murghabian, according to the index fossils.