Microfacies and Paleogeography of Chehelkaman and Khangiran Formations (Paleogene) transition, east of Kopet-Dagh basin

Kopet-Dagh basin is located in north and northeast of Iran. Chehelkaman and Khangiran Formations are the most important formations of Paleogene settings. Upper parts of Chehelkaman Formation in the Chehelkaman Syncline section consist of sandy limestone, marl and limestone with transition contact into Khangiran Formation is conformable and transitional. In this study depositional condition of the top of Chehelkaman Formation and base of Khangiran Formation based on gastropod fauna and trace fossils were studied. These trace fossils in accosiation with tidal flat and lagoon facies that indicate of depositional in the shallow depth environment. Also in this study Globularia genus from Ampullinid gastropods for first time recognized of Kopet- Dagh basin.Because of this genus related with lagoon facies, can be indicate of shallow depth environment for the top of Chehelkaman Formation too. Paleobiogeography of this genus indicates of dependency of Kopet- Dagh basin to tethys realm. So far this genus reported of parts of Central Asian, Eastern Europe, Central Europe and Western Europe. This genus is in the top of Chehelkaman Formation of Kopet-Dagh basin, whearas this genus reported in the layer of post Early Eocene in Erope. This subject indicates migration direction of this genus from east toward west. So can be elicitation that the turan basin is the easternmost of the presence and occurrence of this taxon. In duration of this migration direction from east to west, Anatulian basin of Turkey exposure in the middle of this migration direction.