Depositional environment and sequence stratigraphy of mixed siliciclastic-carbonate deposits of Aitamir Formation (Bazangan area- east of Kopet Dagh Basin)

The Aitamir Formation (Albian- Cenomanian) in the Kopet- Dagh Basin consists of fine to medium grained sandstone، siltstone، shale and limestone. Its lower contact with the Sanganeh Formation is gradual and its upper contact with The Abderaz Formation is unconformable. Field and petrographic studies of the Aitamir Formation in Artenj and Ghorghoreh sections، located in Bazangan area- east of Kopet- Dagh Basin، led to identification of 3 facies association consisting of sandstone، mudrocks and limestone. Based on this study، they were deposited in marine، shoreface، barrier and Lagoon environments. Five depositional sequences in Artenj section and four depositional sequences in Ghorghoreh section were identified based on field observations، facies and sequence stratigraphic analysis. In studied sections، the sequence boundary of the first depositional sequence is in the Sanganeh Formation and upper boundary of the last sequence with the Abderaz Formation is type 1 but the rests are type 2 (SB2). The transgressive parasequences (TST) including a predominance of deep facies and regressive parasequences (HST) contains shallow facies parasequens. Interpretive sea level curve of studied sections are relatively comparable with the world wide curve. However، some differences could be occurred due to regional events.