Lithostratigraphy and Biostratigraphy of the ammonites from the Upper Chaman Bid Formation (Tithonian) at the type locality (NE Iran, Koppeh Dagh)

The present study deals with the ammonites from the upper part of the Chaman Bid Formation, member 4 (Middle-Upper Jurassic) at the type locality. Lithostratigraphicall, it is consites alternation of limestone and marls.Following ammonite families are present: Perispinctidae, Ataxioceratidae, Haploceratidae, Oppeliidae and Aspidoceratidae, which indicate the Biozones: Hybonoticeras hybobotum , Semiformiceras semiforme , Semiformiceras fallauxi , Microcanthoceras ponti and Micracanthoceras micracanthum Zones. Paleobiogeographicall, the ammonite fauna is closely related with the Submeditteranean Provice, with few affinities to South Tethys (Ethiopian province ),migrated during the Tithonian. Following taxa are reported for the first time fromthe Tithonian strataNorth Iran: Zappalia cf. zapalensis, Paraulacosphinctes transitorios, P. seneoides.