Microfacies analysis, Depositional Environment and Biostratigraphy of the Early Eocene Dungan Formation, Kohlu area Balochistan, Pakistan

Abstract The shallow marine carbonate sequences of the Dungan Formation are well-exposed in Sulaiman Fold-Thrust Belt, Eastern Neotethys, Pakistan. In the study area, Palaeogene carbonate platform deposits of the Dungan Formation consists of medium to thick bedded shallow marine carbonate sediments. The exposed outcrop has a thickness of 56 m, underlain by Cretaceous Pab Formation and overlain by Eocene Ghazij Group. The Dungan Formation was analyzed for microfacies, depositional environment and the age diagnostic Larger Benthic Foraminifera (LBF) were utilized to date the formation. The formation contain rich LBF assemblages such as nummulitids, alveolinids Lockhartia, Orbitolites, miliolids and algae. The identified LBF suggest that the deposition of the Dungan Formation occurred in SBZ 5 to SBZ 7 biozones. On the basis of LBF, other associated biota, and the amount of matrix, six carbonate microfacies have been identified. These microfacies are interpreted to have been deposited in two major depositional environments including inner and middle ramp settings.