تاريخچه رسوبگذاري و چينه نگاري سكانسي سازند كلات در غرب كپه داغ و مقايسه ان با بخش مركزي حوضه

Depositional History and Sequence Stratigraphy of Kalat Formation in West of Kopet Dagh and comparison with Centeral part of Basin

Kalat Formation (Upper Masstrichtian) consists of carbonate strata and is exposed along the outcrop belt in the Kopet Dagh basin. Two stratigraphic sections (Garmab and Jozak) in western and three (Dareh Gaz, Shamsikhan and Karnaveh) in central parts of the Kopet Dagh have been measured and petrographic of collected samples led to identification of 10 lithofacies. These litho-facies were deposited in carbonate ramp in tidal flat, lagoonal, barrier and open marine environments. These strata are composed of two depositional sequences in studied sections. The lower sequence in central sections consist of SMW (Shelf Margin Wedge), TST (Transgressive system tract) and HST (Highstand system tract) phases, while the second sequence is composed of TST and HST. The western sections are similar to the central part except the SMW is absent. Lower boundary of Kalat Formation in central part with Neyzar Formation is gradual (type 2) and in western part is erosional with Abderaz and Sanganeh Formations and its upper boundaries with Pesteliegh Formation is erosional (type 1). Paleogeographic reconstruction of studied area during the Upper Masstrichtian time shows that this formation was formed during 5 Transgressive-Regressive phases. Interpreted sea level curve in studied sections are comparable with worldwide curve during Upper Masstrichtian time.