Ichnology of the Middle Jurassic Deposits of NE Iran: Depositional Environment Interpretation

Abstract

The Kopet Dagh Basin of northeast Iran formed in the Neotethys Ocean after the closure of Paleotethys in the south of Turan plate. A thick sequence of Jurassic to Miocene sediments has been deposited in this basin without any major break. The siliciclastic Kashafrud Formation (Middle Jurassic), overlying unconformably on Triassic rocks and ultrabasic rocks of turbidite and fluvio-deltaic facies, consists of sandstone, shale and conglomerate. Trace-fossil assemblages are presented in some units with different environments. The most important ichnofossils in this formation are Skolithos, Palaeophycus tubularis, Belorhaphe, Taenidium, Planoloites beverleyensis, Thalassinoides suevicus, Conichnus, Psilonichnus, Lophoctenium, Palaeophycus striatus, Rhizocorallium jenense and Scolicia.. It is interpreted, based on identified ichnofossils, the starat may have been deposited in fluvio-deltaic and deep water (turbidity conditions) environment.