Facies, Depositional Environment and Diagenesis of the Qom Formation in Rameh Section (Northeastern Garmsar)

Deposits of the Qom Formation (Oligocene-Miocene) in Rameh section are located in northeastern Garmsar and contain dominantly 420 m Limestone, pebble-rich to sandy Limestone and marl Limestone. This formation is unconformably overlaid and underlaid with siliciclastic deposits of Upper Red Formation and Lower Red Formation. Field observations, along with laboratory investigations, have resulted in identifying tidal flat, lagoon, shoal and open marine environments in the studied formation. Open marine facies association consists of bioclast mudstone, bioclast wackestone, bioclast packstone and bioclast roadstone; shoal facies association consists of ooid grainstone, bioclast grainstone and coral boundstone; lagoon facies association is composed of dolomitic mudstone, intraclast bioclast wackestone and bioclast packstone; and tidal flat facies association is sandy dolomudstone and stromatolite boundstone. The qom formation rocks in Rameh section are deposited in a rimmed shelf carbonate ramp. This formation undergoes various diagenetic processes including dissolution, porosity, cementation, micritization, compaction and dolomitization.