Record of the Equivalent of The Upper Bakhtiari (Bai Hassan) Formation in The Chwarta-Mawat Area Within Zagros Thrust Zone, Kurdistan Region, NE-Iraq

Section: Research Paper
Published
Jun 24, 2025
Pages
87-102

Abstract

This study is concerned with a thick succession of polymictic conglomerates which is exposed in the Chwarta, Mawat and Qandil areas inside the Imbricated and Thrust Zone. It is about 1500 m thick and comprises pebbles of boulders of chert, limestone and metamorphic rocks which was previously considered as unit three of the Red Bed Series of the Eocene age. This unit is located inside the trough of a deformed syncline (Chwarta-Mawat syncline) and the youngest succession in the area. The limestone boulders and gravels contain Nummulite and Alveolina of Middle Eocene which belong to the Naopurdan Formation. The limestone clasts of this conglomerate and those of the Upper Bakhtiari Formation (in the Chamchamal area) are compared with those outcrops of the Naopurdan Formation in the Thrust Zone. This comparison is achieved in the field and by thin sections under stereoscopic and polarized microscope showing the same degree of lithification, the content of fossils, fractures and faults in the three units. Therefore, depending on these features, and stratigraphic position, the present study concludes that the Upper Bakhtiari Formation occurs in the Chwarta, Mawat and Qandil areas. The fossil-bearing limestone clasts are derived from erosion of the outcrop of the Naopurdan Formation in the Thrust Zone in the north of Mawat and Chawrta towns. There is agreement that this formation was uplifted (with many older formations) in the Late Miocene- Pliocene and its erosion supplied fossiliferous limestone boulders and gravels to the basin of Upper Bakhtiari in the Thurst, Imbricate, High and Low Folded Zones. This study is the first study to prove (with evidence) the presence of the Upper Bakhtiari Formation inside the Imbricated and Thrust Zone in the Mawat-Chawrta and Qandil area in addtion to its outcrops of the formation in the Low Folded Zone.

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How to Cite

Al-jubory, A., علي, Haji karim, kamal, كمال, Ibrahim Fattah, A., & أمانج. (2025). Record of the Equivalent of The Upper Bakhtiari (Bai Hassan) Formation in The Chwarta-Mawat Area Within Zagros Thrust Zone, Kurdistan Region, NE-Iraq. Iraqi National Journal of Earth Science (INJES), 25(1), 87–102. https://doi.org/10.33899/earth.2024.144691.1178

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