Middle to Upper Triassic Deep-Water Trace Fossils from the Ashin Formation, Nakhlak Area, Central Iran

The up to 304 m thick, turbiditic, siliciclastic Ashin Formation (Upper Ladinian to Lower Carnian?) crops out widely in the Nakhlak area of central Iran. The rocks consist mainly of turbiditic volcaniclastic sandstones and shales that were deposited in distal parts of submarine fans of the continental slope to abyssal plain. Trace fossils occur commonly in the lower parts of the turbiditic volcaniclastic sandstones and belong to 17 ichnotaxa including ?Chondrites isp., Ctenopholeus kutscheri, Helminthopsis abeli, H. tenuis, H. hieroglyphica, Laevicyclus rotaeformis, Lorenzinia nowaki, Megagrapton isp., Ophiomorpha isp., Palaeophycus isp., Paleodictyon cf. maximum, Protopaleodictyon incompositum, Protovirgularia isp., and Thalassinoides isp. The trace fossil assemblage belongs to the deep-sea Nereites ichnofacies. In particular trace fossils such as Paleodictyon, Protopaleodictyon, Megagrapton and Lorenzinia indicate that the Ashin Formation represents a deep marine environment.