Biostratigraphic study of Pabdeh formation in North of Dezful embayment (Qalenar oil field)

The Pabdeh Formation is one of the major rock units in the Zagros Basin is the source rock. Biostratigraphic study Pabdeh formation led to the identification of 62 species and 23 genera of calcareous nannofossils. According to the first occurrence and Last Occurance of index species and fossil assemblages, Fourteen biozones of Martini (1971) (Tribrachiatus contortus Zone (NP10), Discoaster binodosus Zone (NP11), Tribrachiatus orthostylus Zone (NP12), Discoaster lodoensis Zone (NP13), Discoaster sublodoensis Zone (NP14), Nannotetrina fulgens Zone (NP15), Discoaster tani nodifer Zone (NP16), Discoaster saipanensis Zone (NP17), Chiasmolithus oamaruensis Zone (NP18), Isthmolithus recurvus Zone (NP19), Sphenolithus pseudoradians Zone (NP20), Ericsonia subdisticha Zone (NP21), Helicosphaera reticulata Zone (NP22), Sphenolithus predistentus Zone (NP23)) equivalent to biozones CP9a- CP17 of Okada and Bukry (1980) have been recognized. As a result of this study and based on the identified zones, age of the pabdeh formation in the North of Dezful Embayment is Ypresian to Rupelian.