The latest Carboniferous-Early Permian Dorud Group of the eastern Alborz (Iran): biostratigraphy and taxonomy of smaller foraminifers

The latest Carboniferous-Early Permian Dorud Group in the Chaman-Saver area of eastern Alborz, Iran is more than 222m thick and includes thick sequences of oncolitic limestone, sandy limestone, sandstones and shales. The Emarat and Ghosnavi formations of this Group are dated here as latest Gzhelian to early Sakmarian Stages. During the Asselian Stage, the sea level fell abruptly and epeirogenic episodes occurred. These events generated a broad, shallow carbonate platform suitable for the growth and diversity of smaller foraminifers in the Chaman-Saver area which, consequently, displays faunal differences with the rest of the Alborz Mountains. Three foraminiferal biozones are proposed: Nodosinelloides potievskayae-Vervilleina bradyi Zone (latest Gzhelian), Calcitornella heathi-Nodosinelloides sp. Zone (latest Gzhelian-Asselian), and Rectogordius iranicus n. gen. n. sp.-Hemigordius schlumbergeri Zone (early Sakmarian). The new taxa described herein include: Pseudovidalina iranica n. sp., P. damghanica n. sp., Rectogordius iranicus n. gen. n. sp. and Tezaquina sp. 1. Copyright (c) 2012 John Wiley & Sons, Ltd.