Discovery of Late Mississippian (late Serpukhovian)–Early Pennsylvanian (earliest Bashkirian?) foraminiferal assemblages from the Sanandaj–Sirjan Zone, Iran: Biostratigraphic and palaeoenvironmental implications

This study reports the new discovery of relatively abundant foraminiferal faunas from the upper Serpukhovian–lowermost Bashkirian? of the Ghaleh Formation in theShahreza region of the Sanandaj–Sirjan Zone, Iran. Four successive assemblages spanning the upper Serpukhovian–lowermost Bashkirian? are proposed: (1) Assemblage with Biseriella minima and Eostaffellina paraprotvae; (2) Assemblage with Bradyina cribrostomata; (3) Assemblage with Parastaffella utkaensa and Plectostaffella spp., (4) Assemblage with Plectostaffella ex gr. varvariensis. The newly discovered foraminiferal assemblages of the Sanandaj–Sirjan Zone have some species in common with assemblages of the Russian Platform, Donets Basin, Urals, and Western Europe. Ikensieformis aff. mirifica, and Eostaffella igoi, and a new species Ikensieformis persiaensis sp. nov. are described. The microfacies analysis of the Ghaleh Formation limestones suggests a moderate to high-energy shallow marine warm environment, more likely of the inner ramp.