عنوان مقاله [English]
Investigation of conodontic fauna of Late Devonian-Early Carboniferous (Tournaisian) deposits of Jeirud and Mubarak formations in Tuyeh-Darvar section, southwestern Damghan, East Alborz, led to the identification of 32 species of 10 conodontic genera and accordingly 12 conodont zones were separated in the studied interval; of these, 9 biozones belong to the Late Devonian (Late Famennian) and 3 biozones belong to the Early Carboniferous (Tournaisian). The Devonian / Carboniferous boundary is discontinuous and corresponds to the thin sandstone horizon at the base of the first limestone unit of the Mubarak formation. Based on field observation and sedimentological features and characteristics, the section, subdivided into 9 lithostratigrafic units. Conodont biofacies interpretations show Gradual and recurrent increase in sea level at Late Famennian which continues at lower Tournasian and that is relatively accordance to the global sea level due to the shallower marine than the other studied profiles at Europe and American basins.