Microfacies analysis and depositional environment of the Upper Cretaceous rocks in Tang‐e Vanak section (Central Zagros Basin, SW Iran)

Abstract

The Tarbur Formation is a carbonate stratigraphic unit in the Zagros Basin. This formation is exposed between the Main Zagros Reverse and High Zagros faults and Sabzpoushan Fault. In this study, we describe the depositional characteristics of the Upper Cretaceous sediments (Tarbur Formation) in the Tang‐e Vanak section. In this section, the lower conglomeratic boundary below the Tarbur Formation is named the Amiran Formation and the upper boundary of the Tarbur Formation is disconformably overlain by white dolomitic deposits of the Shahbazan Formation. The Tarbur Formation was interpreted to be deposited in a carbonate homoclinic ramp due to the lack of a deep lagoon environment in the back of the reef structures and the turbidity sediments in its frontal margin. Based on this study, 8 microfacies were recognized including (1) Algal‐foraminiferal wackestone/packstone (2) Bioclastic‐ algal wackestone/packstone, (3) Intraclast bioclastic packstone, (4) Coral boundstone, (5) Rudist boundstone, (6) Bioclastic grainstone, (7) Bioclastic‐foraminiferal wackestone, and (8) Planktonic foraminiferal intraclastic wackestone/packstone. These microfacies were located in the inner, middle, and outer ramp.