Document Type: Original paper (Research paper)
Department of geology, faculty of science, University of Isfahan
Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran.
Department of Geology, Faculty of Science, Payam Noor University, Tehran, Iran.
The present reseach focuses on a collection of Bathonian-Oxfordian ammonite fauna from the Dalichai Formation in Mahdishar (northern Semnan, Iran), followed by the description of the sedimentary succession of Kuh-e-Rahband area. In the studied section, the Dalichai Formation is characterized by 122 m of thick marls and grey medium to thick-bedded limestones and argillaceous limestones with chert nodules, deposited in a deep basinal setting. Four lithostratigraphic units are distinguished in this paper. The studied ammonite fauna consists of 40 specimens attributed to the families, Phylloceratidae, Perisphinctidae, Oppeliidae and Aspidoceratidae: Palaeobiogeographically the fauna shows close relationships with Western Europe and the Sub-Mediterranean regions.