UPPER CARBONIFEROUS-PERMIAN STRATIGRAPHY AND FUSULINIDS FROM THE ANARAK REGION, CENTRAL IRAN

Abstract

The section of Upper Carboniferous (Gzhelian) and Lower Permian (Asselian-Sakmarian) sediments in the Anarak region of central Iran was first thoroughly studied. The sediments are subdivided into two units, the lower, 95-m-thick, significantly calcareous Zaladou Formation and the upper, 100-m-thick, dolomitic Tighe-Maadanou Formation. The formations are united in the Anarak Group separated from the under- and overlying deposits by stratigraphic hiatuses. The Zaladou Formation contains fusulinids from top to bottom. At the base they are represented by species characteristic equally of the uppermost Kasimovian and the lower zone of the Gzhelian. The middle Gzhelian species were encountered at 70 m above the base and still higher the typical uppermost Gzhelian forms referred to the Ultradaixina bosbytauensis Zone, occur. The upper 6 m of the section are assigned to the Asselian including its lower and middle zones. Dolomites of the Tighe-Maadanou Formation lack faunal remains. According to the position in the section they are referred to the uppermost Asselian and to the Sakmarian. The described section is similar to that in the Ozbak-Kuh Mountains north of Tabas, where the both formations of the Anarak Group are recognized. West of Tabas, in the Kalmard region, the Khan Formation can be correlated with the group; in the Alborz, the Dorud Formation; and in northern Zagros (Abadeh region), the Vazhnan Formation, respectively. The fusulinid assemblage recorded in the studied section includes 70 species referred to 21 genera and 12 families. They are illustrated in 10 paleontological plates. Seven new species and subspecies Schwageriniformis acutatus, Rauserites stepanovi, R. (?) persicus, Rugosofusulina (?) iranica, R. (?) anarakensis, Ultradaixina bosbytauensis distincta, and Likharevites gracilis are described.