Biostratigraphy of Pabdeh Formation based on calcareous nannofossils, southwest of Ilam, Ilam province

• Main Authors: saeideh senemari, Afsaneh Deh Bozrgi
• Format: Article
• Language: fas
• Published: University of Isfahan 2017-11-01
• Series: Journal of Stratigraphy and Sedimentology Researches
• Subjects: Ilam; Biostratigraphy; Paleogene; Zagros Basin; Pabdeh Formation
• Online Access: http://jssr.ui.ac.ir/article_22227_6e321f359b0eb36089ba4e1fdf626768.pdf

In order to study biostratigraphy of the Pabdeh Formation in southwest of Ilam, Marbera section was selected. In this section, Pabdeh Formation is mainly consists of marls, shale and marly limestones. The study of calcareous nannofossils led to the recognition of 72 species and 26 genera. According to the first and last occurrence of index species and based on Martini (1971) zonation, the following biozones are identified:, Tribrachiatus contortus Zone (NP10), Discoaster binodosus Zone (NP11), Tribrachiatus orthostylus Zone (NP12), Discoaster lodoensis Zone (NP13), Discoaster sunlodoensis Zone (NP14), Nannotetrina fulgens zone (NP15), Discoaster tanii nodifer Zone (NP16), Discoaster saipanensis Zone (NP17), Chiasmolithus oamaruensis Zone (NP18), Isthmolithus recurvus Zone (NP19), Sphenolithus pseudoradians Zone (NP20), Ericsonia Subdisticha zone (NP21), Helicosphaera reticulate Zone (NP22), Sphenolithus predistintus Zone (NP23), Sphenolithus distentus Zone (NP24), Sphenolithus ciperoensis Zone (NP25). As a result of this study and based on the obtained biozones, the age of Pabdeh Formation in southwest of Ilam, is Early Eocene (Ypresian) to Late Oligocene (Chattian).