FACIES DISTRIBUTION AND PALAEOECOLOGY OF THE GURI MEMBER OF THE MISHAN FORMATION, IN LAR AREA, FARS PROVINCE, SW IRAN*

Abstract

This research is focused on facies distribution, palaeoecology and palaeoenvironment of the GuriMember of the Mishan Formation in Kuh-e Shur and Kuh-e Kurdeh sections at the Lar area, Fars province.The Guri Member is composed of limestone, marly limestone and marl and the thickness at Kuh-e Shur andKuh-e Kurdeh is about 72 and 110 meters, respectively. Based on petrographical studies of 120 thin sections, 8 microfacies have been identified that are deposited in open shelf environment (inner and middle shelf). Palaeolatitudinal reconstructions based on skeletal grains suggests that carbonate sedimentation oGuri Member took place in tropical waters under oligotrophic conditions, a typical environment for photozoan assemblages. These biotic assemblages of the Guri Member belong to foralgal association and may be broadly defined as comprising heterozoan assemblages. An important factor controlling the spread of heterozoan assemblages during the Early Miocene in the study areas seem to be related to the palaeoecology and evolution of zooxanthellate corals.