New findings on sequence stratigraphy of the Ruteh Formation in the North of Central Alborz

The Ruteh Formation with a thickness of 642 m, mainly consisting limestone, dolomitic limestone and shale, disconformably lied on Sandstone and underlied disconformably by Nessen Formation. Based on petrographic studies of 200 thin-sections and sedimentary structures of the Ruteh Formation Identified and separated 18 carbonate microfacies and one clastic facies that deposited 4 facies belt of tidal flat, lagoon, shoal and open marine. The sedimentary environment of middle and late Permian deposits in the Alborz area is very similar to the recent carbonate environments in the Persian Gulf. The sediments are formed in shallow environments in the epicontinental platforms. The sedimentary environment of the Ruteh Formation is identified as a homoclinal ramp. Sequence stratigraphy studies have been carried out based on the accurate determination of sedimentary environments and field studies. From sequence stratigraphy point of view, a third-order sequence of the late morghabin age, three third-order sequences to the early, middle and late midian age and two third-order sequences to early and late Julfian age is determined