Platform to Basin Facies Transition in the Lower Cretaceous Fahliyan Formation: Evidence for the Formation of Garu Intra

The Fahliyan Formation (Berriasian-Valanginian) is an important petroleum reservoir in southwest Iran. Field and microscopic investigation of the Fahliyan Formation in the Izeh Zone, west of Kazroon Fault, resulted in recognition of platform and off platform basinal (calciturbidite and pelagic) facies. Lateral and vertical facies variations of the Fahliyan Formation in the study area indicate deposition in settings related to a carbonate shelf with an east facing shelf margin. Platform facies in the type locality (Fahliyan section) changes towards the northwest in the Eshgar section to chiefly basinal pelagic and calciturbidite facies. In the Eshgar section, mainly calciturbidite facies, sharply overlies the platform facies of the lower part of the Fahliyan Formation suggesting the onset of tectonic activity along the Kazroon Fault system in Early Cretaceous leading to the formation of the north to south trending Garu Intrashelf Basin in southwest Iran