Introduction to Permian Microfossils in Aru and Bibi Shahrbanoo Area (Albourz)

The Permian sequences of Aru and Bibishahrbanoo sections comprise the Dorud، Ruteh and Nesen formations respectively. A precise dating of the formations was provided based on the analysis of smaller foraminifers and fusulinid assemblages. The clastic Dorud Formation refered to Asselian and Sakmarian stages. The platform limestone of Ruteh Formation corresponds to Kubergandian - Murgabian stages. The Laterite and Bauxite horizon in the studied area attributed to Midian and finally، the uppermost beds of Permian in Bibisharbanoo corresponds to Early Dzhzulfian، based on the proposed of international subcommission on Permian stratigraphy concerning Tethyian stage bourdaries. Biolithic limestones of Ruteh Formation lying transgressively and disconformably on the underlying clastic and continental Dorud Formation with a great hiatus consists of Yachtashian and Bolorian stages. In both stratigraphical sections، thin vermiculate and oolithic limestone of Elika formation belonge to Early to Middle Triassic lying disconformably on the Permian sequence with hiatus. The hiatus between Permian and Triassic in Aru comprise Dzhulfian and Dorashamian stages and in Bibi Shahrbanoo stratigraphical section include Late Dzhulfian and Dorashamian stages. In this study 45 species belonging to 40 genus related to fusulinid families، smaller foraminifers and calcareous algae were recognized.