Calcareous Nannofossils Biostratigraphy of the Upper Part of Gurpi Formation- Lower Part of Pabdeh Formation (Purple shale) at the North-East of Gurpi Anticline

In this study the upper part of Gurpi Formation and the lower part of Pabdeh Formation have been investigated with regard to the calcareous nannofossils. The thinkness of the studied section is about 127 meter and it consists of Marls, gray-green shales and purple shales. 50 genus and 101 species of calcareous nannofossils have been recognised in the studied section. According to the index genus and species in the studied inteval, calcareous nannofossil biozones CC25-CC26 have been recognized at the cretaceous sediments and NP1-NP5 and NTp1-NTp9 biozones have been determined at the Paleocene sediments that NP1-Np4 and NTp1-NTp7A biozones are reported for the first time from the upper part of Gurpi Formation at the studied section. With regard to these biozones, the age of the upper part of Gurpi Formation in the studied section is late Maastrichtian- late Danian (late early Paleocene) and the age of Pabdeh Formation is started from early late Paleocene. According to the nannofossil data, the K/Pg boundary is continuous and is located at the upper part of Gurpi Formation. The K/Pg boundary is marked by a decrease in abundance of Cretaceous species, increase in the abundance of Thoracosphaera operculata and the appearance of the new-Paleocene taxa. In the Danian sediments the Cretaceous species are present along with Paleocene species continuously and with a good preservation that can be considered as surviving species that may have passed the boundary and are present at the Danian sediments.