Depositional environment and diagenetic history of Fahliyan Formation in Lar anticline, south of Izeh Zone

The Fahliyan Formation contains relatively thick carbonate sequence which belongs to the Khami Group with Neocomian-Barremian age. This study investigated this unit in Lar anticline in Izeh Zone, which led to the identification of 25 microfacies in 4 facies belts. In the Fahliyan Formation, the remains of the framework builders such as hermatypic corals and algaes are scarce, while grain-supported shoal facies show good deveolpment. Suggested depositional environment for this carbonates in the Lar anticline is a homoclinal carbonate ramp and dominantion of grain-supported facies indicates windward side of a ramp. Seemingly, barrier-bank complexes were developed in this area along the ramp shoreline which lead to dominance of bioclastic grainstone, bioclastic-peloidal wackestone-packstone facies, and calcareous sandstones. In addition, presence of stromatoporoid along with thick shoal facies may indicate a wave-dominated ramp. The most significant and effective diagenetic processes in the studied unit in the Lar anticline include micritization, compaction, dolomitization, dedolomitization, silicification, pyritization, cementation, and fracturing that occured in different stages of marine, meteoric, burial and telogenetic diagenesis.