Syn-depositional continental rifting of the Southeastern Neo-Tethys margin during the Albian–Cenomanian: evidence from stratigraphic correlation

ABSTRACT

Albian–Cenomanian successions (Kazhdumi and Sarvak formations) represent remarkable variations in thickness, facies, fauna, and environments throughout the Zagros area. In the Coastal Fars (Charmu section), sedimentological and paleontological data evidence an intrashelf, with depths of 10s–100s m, surrounded by a shallow carbonate platform. Due to its depth, deposition of sequences in this setting has been controlled by eustatic sea-level changes rather than eurybathic changes, and several condensation episodes occurred related to marine transgressions. These observations are different from those in the adjacent sections in the Coastal Fars which recorded subaerial exposures instead. Combined with previous studies, this study denotes several intrashelf basins enclosed by a shallow carbonate platform on the southeastern margin of the Neo-Tethys during the Albian–Cenomanian. Development of intrashelf basins corresponds to basement faults in the Fars Salient. Likely, an extensional tectonic regime associated with a rifting event created horst–graben architecture by exerting extension along the basement faults and reactivating salt structures. Deposition on these troughs and highs led to the facies and thickness variations of the concomitant sequences. Development of several intrashelf basins on the southeastern margin of the Neo-Tethys indicates that syn-depositional continental rifting event could occur during the Albian–Cenomanian, prior to the tectonic inversion around the earliest Turonian.

KEYWORDS:

• Albian–Cenomanian sequences
• horst–graben architecture
• continental rifting
• Kazhdumi formation
• Sarvak formation
• coastal fars

Acknowledgments

Damghan University is thanked for providing facilities for this research. M Pirouz, S Eslami, C Neto de Carvalho, H Shafaii Moghaddam, and R J Stern are deeply thanked for their technical advice. F. Nazemnejad is thanked for preparing maps. Our special thanks go to Mariano Parente and an anonymous reviewer for their critical comments that considerably increased the quality of the manuscript. Morvarid Gharch-e Jam Cooperation Company provided logistic supports including vehicle, tools, and resort, for which the authors are grateful.

Disclosure statement

No potential conflict of interest was reported by the authors.