Biostratigraphy of the Pabdeh Formation based on planktonic foraminifera in the Tang-e-Chogan section in Interior Fars, Zagros Basin

• Main Authors: Zahra Khaloasgari, Mahnaz Amirshahkarami, Koorosh Rashidi Sharifabad
• Format: Article in Journal/Newspaper
• Language: Persian
• Published: University of Isfahan 2023
• Subjects: pabdeh formation; planktonic foraminifera; early eocene–late eocene; biostratigraphy; Stratigraphy; QE640-699; Planktonic foraminifera
• Online Access: https://doi.org/10.22108/jssr.2023.134029.1234; https://doaj.org/article/0d31b1acd5354671ad393e2c50a7adb6

Abstract The biostratigraphy of the marly-limestone Pabdeh Formation has been studied in a section located in the Interior Fars (folded Zagros). Five assemblage biozones of plankton foraminifera with Early Eocene to Late Eocene age were identified in the studied section. Biozone 1 with a thickness of two meters has been identified at the base of the studied succession and includes Morozovellavela scoensis and Morozovella conicotruncata species defining the Early Eocene age. Biozone 2 with a thickness of 59 meters is the Early Eocene in age and is associated with the first occurrence of Morozovella aragonensis at the base and the last occurrence of Chiloguembelina wilcoxensis at the top. Biozone 3 with a thickness of 66 meters is defined by the first occurrence of Globigerinatheka kugleri at the base and the occurrence of Guembelitrioides nuttalli at the top and represents the beginning of the part of the Middle Eocene. The presence of Orbulinoides beckmanni indicates the Middle Eocene for biozone 4 with a thickness 88 meters. Biozone 5 with a thickness of 163 meters indicates the Middle–Late Eocene for the top of studied succession according to the first and last occurrence of Hantkenina alabamensis. Keywords: Pabdeh Formation, Planktonic foraminifera, Early Eocene–Late Eocene, Biostratigraphy Introduction The Laramide orogeny event is one of the tectonic events affecting the geology of Iran, which played a significant role in the formation of independent Cenozoic sedimentary basins of Iran (Aghanabati 2004). The subduction of Neotethys under the Iranian Plate began in the Upper Jurassic–Lower Cretaceous and was accompanied by the evolution of the present-day tectonic structure of Zagros in the Upper Paleocene–Lower Eocene (Heidari 2008). The Zagros sedimentary basin has three sedimentary units: Khuzestan Plain, folded Zagros or external Zagros, high Zagros or internal Zagros (Darvishzadeh 1991). After the Late Cretaceous movements, in the Early Paleogene, the whole Zagros was covered by an progressive sea. In ...