ميكرو فاسيس ها و محيط رسوبي نهشته هاي كربونيفر در برش اسد آباد- ناحيه رامشه جنوب شرق شهرضا- جنوب غرب ايران مركزي

Microfacies and Depositional Environment of Carboniferous Sediments in Ramsheh Area, South-east of Shahraza, Southwest Central Iran

The studied section is located in Central Iran, 135 km southeast of Isfahan in Ramsheh area (latitude N 31° 46ʹ 65 longitude E 52° 8ʹ 63") GPS-WGS84 coordinates. The Ramsheh area structurally belongs to the Southwest-Central Iran and is checked regarding to microfacial and paleoinvironmental points of view as well as to biostratigraphical evidences. Carboniferous depositions (including Shishtu II sub Formation and Sardar Formation) are formed from limestones, dolomylimestones, shales, sandylimestone, sandstones and oolitich limestones. Based on detailed petrographical investigations and field studies, 15 micofacies have been identified: 13 of them belong to carbonate microfacies that form in four sub-sedimentary environments, including Open marine, Barrier, Lagoon and Tidal flat and the other 2 microfacies show clastic material presence. The facies sequences observed in the carbonate platform sedimentation are the result of changes in environment through time and by natural processes operating within the environment or by fluctuations in the external factors controlling sedimentation such as tectonic activities and change in a sea-level. A characteristic of carbonate platform is its continuation without any breakage into the deepwater sedimentation.