Study of Neyzar Formation based on Ostracods in Chahchaheh section (Razavi Khorasan)

Nizar Formation is one of the most rock-forming formations of the Upper Cretaceous of Kopet-dagh sedimentary basin, which is composed of glauconitic sandstone and shale. In terms of fossil diversity, it is not reported in most sources for that fossil diversity, but in parts of Shale, different species of dinoflagellates have been reported by the author. With the initial sampling, the presence of ostracod in the shale parts of the formation was confirmed. Therefore, 40 samples were collected from the shale sections of the Neyzar Formation to study the formation based on ostracods. The biodiversity of ostracods in the shale parts of the formation is very high. 20 genera and 22 species of ostracods were identified and based on them, the paleoenvironment of Neyzar Formation was analyzed. Finally, a warm environment with very variable salinity and relatively low depth was considered for the shale parts of the Neyzar formation during the accumulation of sediments.