Introducing of Nayband Formation Microproblematic fossils in Hasan-Abad section, northwest of Ferdows and their importance in paleoenvironmental studies

The Nayband Formation sediments contains of abundant macrofossils such as corals, sponges, gastropods, bivalves, foraminifera and microproblematic fossils. Less attention has been given to these microproblematic fossils. In this research, Hasan-Abad stratigraphic section, northwest of Ferdows city, was selected. The Nayband Formation in this area has the Bidestan Member patch reef limestone within this formation. Study of mentioned limestone is led to identification of some microproblematic fossils such as Baccanella floriformis, Bacinella sp., Gosaukamerella eomesozoic, Lithocodium sp., Microtubs communis, Tamatophorella parvovesicuifer, Tubiphytes sp. and some Late Triassic index foraminifers. Scrutiny on microproblematic fossils and their association with foraminifers are important in paleontological studies and explanation of Late Triassic reefal – lagoonal environments. These species belong to shallow marine reef or carbonate platform and suggest a shallow reefal environment in photic zone with clear water in the inner ramp platform. Sedimentation during deposition of the Bidestan Member in the Late Triassic time may have taken place in low latitude.