Original paper

Late Jurassic (Oxfordian, Bimammatum Zone) ammonites from the eastern Alborz Mountains, Iran

Seyed-Emami, Kazem; Schairer, Gerhard


From the Upper Jurassic Lar Formation northeast of Jajarm, eastern Alborz, 14 taxa of ammonoids are described. These belong to the following families: Phylloceratidae, Oppeliidae, Glochiceratidae, Perisphinctidae and Aspidoceratidae, most of them recorded for the first time from Iran. The ammonite fauna is Late Oxfordian, Bimammatum Zone, in age. Palaeobiogeographically, the Late Jurassic ammonite fauna of North Iran is closely related to those from epicontinental seas, bordering the northern margins of the western Tethys, intermediate to Mediterranean and Sub-mediterranean provinces. The high percentage of Phylloceratina, occasionally exceeding 50 % of the fauna, indicates a relatively deep marine environment and to some extent closer relations to the Mediterranean Province.


ammonitesupper jurassicoxfordianlar formationalborz mountainsiran