Biostratigraphy and microfacies analysis of the Mid Cretaceous sequence in south Zagros basin

The marine deposits of middle Cretaceous Arabian continental margin are assigned to the Kazhdumi and Sarvak formations and best exposed in the south Zagros Basin (SW Iran). However, detailed studies related to the sedimentary environments, biostratigraphy and microfacies distribution of the middle Cretaceous sequence in south Zagros basin are still scarce. This study presents detailed biostratigraphic and microfacies analysis of the Kazhdumi and Sarvak formations on two sections in the northeast Interior Fars zone to reconstruct the sedimentary evolution of Middle Cretaceous Arabian continental margin. The Kazhdumi Formation is conformably worn by Sarvak Formation. The biozones were encountered in the studied areas and the following seven assemblage zones have been defined. Stratigraphic distribution of identified foraminifers supports Albian to late Cenomanian age of Kazhdumi and Sarvak Formations at the study area. The recognized eleven microfacies in Kazhdumi and Sarvak formations are clustered into lagoon, tidal flat, barrier and open marine sedimentary environments. A carbonate shelf and shallow ramp is suggested for Sarvak and Kazhdumi Formation respectively. The transgressive and highstand deposits reveal a predominance of deep and shallow subtidle facies respectively.