Petrography, Original Corbonat Mineralogy, and Reconstruction of Sedimentary

Mobarak Formation consisting of thick carbonate successions was formed ring Lower Carboniferous in Aru area, Central Alborz, near Tehran. This Formation du disconformably overlain by Dorud (Lower Permian) and underlain by Geirud Formation. Major and minor elements and behavior of and values with trace elements are used for recognition of original carbonate mineralogy. These carbonates are affected mostly by meteoric diagenesis. Facies analysis and petrographic studies led to recognition of 14 microfacies deposited in an open marine, barrier, lagoon and tidal flat environments. The high Sr concentration is due to aragonitic components deposited in lagoon and back barrier settings. Barrier and open marine facies have low Sr and high Fe, Mn and Na concentrations. A ramp platform is suggested as a depositional environment.