Microfacies and palaeoenvironments of the Lower Carboniferous Mobarak Formation in the Kiyasar section, Northern Iran

Carboniferous rocks outcrop over vast areas in the Alborz Mountains. The Mobarak Formation outcrops in the studied area near the Kiyasar town, south-east of Sari, Northern Iran. The petrographic study produced the recognition of fifteen different microfacies types. Based on microscopic studies, four facies belts have been characterized: (1) an intertidal facies belt, (2) a lagoonal facies belt, (3) a barrier (shoal) facies belt and (4) an open-marine facies belt. They are respectively interpreted as inner, middle and outer-ramp carbonates developed in a shallowing-upward sequence.