Moscovian–asselian (middle Pennsylvanian–earliest Cisuralian) Smaller Foraminifers from the Asad-abad Section (sanandaj-sirjan Zone, Central Iran)

Abstract

AbstractCarboniferous and Permian strata crop out in Central Iran. The Asad-Abad section has yielded Gzhelian and Asselian fusulinid levels. Here we describe the smaller foraminifers of this section for the first time and introduce four biozones based on these taxa. Biozone I with Monotaxinoides? melanogaster n. sp. is interpreted to be early?-middle? Gzhelian in age (with possible reworkings affecting up to Moscovian/Kasimovian? levels) based upon the principle of superposition and of previous datings of the underlying series, but in the absence of direct datings by fusulinids of this lowermost part of the section. Further, Monotaxinoides? are generally known in the Bashkirian-Moscovian. Biozone II includes Raphconilia spp., Protonodosaria spp., and Rectogordius? minimus n. sp. and is interpreted as middle?-late Gzhelian in age. Biozone III includes Turrispiroides spp., Calcivertella anguinea, Calcitornella heathi, and Vervilleina crescenticamerata n. sp., and we base its early Asselian age on associated fusulinids. Finally, Biozone IV includes Cribrogenerina? sp. and Nodosinelloides longissima; its middle to late Asselian age, based on fusulinids, is confirmed by associated smaller foraminifers. The foraminiferal assemblages display marked differences in composition and stratigraphic distribution compared with those of Alborz and Tabas Block. Principally, they have unexpected similarities with several North American assemblages, especially the three new species: Monotaxinoides? melanogaster n. sp., Rectogordius? minimus n. sp., and Vervilleina crescenticamerata n. sp.