Lithostratigraphy and biostratigraphy of the Silurian sequence at Robat-e-Qarebil stratigraphic section, based on conodonts

Investigation of Silurian succession equivalent to the Niur Formation at the northwest of Robat-e-Qarebil (instantly south of Western Kopeh-Dagh), is led to introduction of lithostratigraphical units in details and identification of some Llandovery conodonts. The sampled interval in this stratigraphic section is composed of shale, fossiliferous limestone, sandstone, and dolomite with 295.5 meter thickness. With a marine volcanic rock unit at the base, this succession is conformably overlaid shales and sandstones attributed to the Ordovician system and overlain by quartzarenite and red shales of the Padeha Formation. Obtained conodonts from these sequences comprise different coniform, ramiform and pectiniform elements. Nineteen species of 10 genera belong to Aspelundia expansa Interval Zone which confirms uppermost Late Rhuddanian to Aeronian for the section. This age coincides with the ages which have already been given on the basis of brachiopods, cephalopods and palinomorphs for the same outcrops at the Western Kopeh-Dagh.