Depositional environment and sequence stratigraphy of Jeirud Formation in Mobarakabad Valley and Northeast of Zaigon village

Abastract

The silisiclastic deposits of the Jeirud formation (Upper Devonian) in Northeast of Tehran (Mobark-Abad valley, N: 35° 47´ 10ً  , E: 51° 58´ 25ً  & Zaigon village N: 35° 58´ 49ً  , E: 51° 36´ 28ً, ) have been studied for recognition of their depositional environments and sequences. These deposits overlay the Mila Formation over a disconformity, and  are  underlain by dark marls and limestones of Mobarak Formation. The present study indicates that the Jeirud Formation is deposited in microtidal wave and storm dominated shallow shelf which contains lagoon, beach/barrier, inlet, estuary, delta and open marine facies. The open marin facies include normal marine deposits and storm deposits. The normal marine deposits consist the proximal and  distal facies. Estuarine deposits are deposited in transgression and delta deposits are deposited in regression. Sequence stratigraphy of the Jeirud Formation have been led to recognition of  four, 3^rd order cycles. The Jeirud Formation is deposited during the frasnian-famenian.