The uppermost Carboniferous (Gzhelian)–Lower Permian (Asselian–Sakmarian) stratigraphy and smaller foraminifers of the Ozbak‐Kuh region (Tabas Block, east central Iran)

Abstract

The uppermost Carboniferous (Gzhelian)–Lower Permian (Asselian to Sakmarian) Anarak Group of the Zaladou section in central Iran is more than 180‐m thick and includes thick units of shale, calcareous sandstone, fusulinid limestone, sandy limestone, and dolomite. The Zaladou and Tigh‐e‐Madanu formations of this group were dated as Gzhelian to Sakmarian. A review of the smaller foraminifers of the Zaladou section is presented. Five foraminiferal subzones grouped in three biozones are proposed in this work: The first assemblage zone (I) is Gzhelian; the second zone (II) corresponds to the Gzhelian–Asselian boundary interval, and the third biozone (III) is Asselian in age. Biozone I is subdivided informally into two subzones: the Hemigordius spirilliniformis‐Bradyina cf. samarica subzone IA (probably early Gzhelian in age) and the Raphconilia modificata and Globivalvulina spp. subzone IB (middle to late Gzhelian); biozone II is the Nodosinelloides spp. zone; biozone III is subdivided informally into two subzones: IIIA with Pseudoacutella partoazari‐Bradyina lucida and IIIB with Planoendothyra persica n. sp.‐Rectogordius sp. The studied assemblages are correlated with those from the Carnic Alps (Austria–Italy), East European Platform of Russia, the Urals (Russia), Darvas (Uzbekistan), the northern and central Pamirs (Tajikistan), northern Iran (Alborz), northern Afghanistan, and other classical regions of the Tethyan realm. The genera Raphconilia and Planoendothyra are revised, and Planoendothyra persica n. sp. is described.