raheleh aghighi

The Aitamir Formation (Albian- Cenomanian) consists of sandstone, shale, siltstone and several limestone beds. Artenj and Ghorghoreh sections have studied in east of basin for determination of the ichnofacies. In this research, trace fossils types and ichnofacies are recognized and their relation with depositional environment has interpreted. Trace fossils in studied sections consist of Arenicolitesisp., Cylinderichnous concentricus, Ophiomorpha isp., Palaeophycus heberti, Paleophycus tubularis and Thalassinoidesisp. that can be placed in glossifunjites and Cruziana ichnofacies. Glossifunjites ichnofacies with low diversity of trace fossils and oblique to vertical orientation of the Y branched Thalassinoides, Paleophycus and Arenicolites in trough and planar cross-bedded were formed in high-energy barrier complex. Whereas Cruziana ichnofacies with higher diversity and mainly oblique to horizontal trace fossils in sandy substrate with low to moderate sorting are formed in low energy condition in shoreface environment.

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.