Russian Journal of Earth Sciences Russian Journal of Earth Sciences Russian Journal of Earth Sciences 1681-1208 46580 10.2205/2021ES000762 ОРИГИНАЛЬНЫЕ СТАТЬИ ORIGINAL ARTICLES ОРИГИНАЛЬНЫЕ СТАТЬИ Biostratigraphical investigation of calcareous nannofossils: The middle Paleogene to early Neogene strata from the eastern parts of Iran (Median Tethys sea-way) Biostratigraphical investigation of calcareous nannofossils: The middle Paleogene to early Neogene strata from the eastern parts of Iran (Median Tethys sea-way) Darestani Mina Ghavidel Darestani Mina Ghavidel mina.ghavidel@gmail.com Khazaei Ahmad Reza Khazaei Ahmad Reza Ferdowsi University of Mashhad ru Ferdowsi University of Mashhad ru Univer- sity of Birjand ru Univer- sity of Birjand ru 21 4 29 10 2021 https://rjes.ru/en/nauka/article/46580/view

In a complete succession obtained from southeast of Birjand, in the Eastern part of Iran, the open marine sediments have been deposited without any disconformity from Paleogene to early Neogene systems. We conducted the biostratigraphic investigations within this sedimentary succession according to calcareous nannofossils from the Roobiat Village section. Based on the calcareous nannofossil species index, we have detected the NP16 to NN3 zones and subzones which are comparable with the Martini biozonation pattern. Thus, we could suggest a middle Eocene (Bartonian) to early Miocene (Burdigalian) age for this section. Since the studied section contains a complete sedimentary sequence from Paleogene to Neogene systems, as a comparisonal section for the correlation between bio-horizons from western parts of the Tethys basin and its eastern parts, it is recommended.

In a complete succession obtained from southeast of Birjand, in the Eastern part of Iran, the open marine sediments have been deposited without any disconformity from Paleogene to early Neogene systems. We conducted the biostratigraphic investigations within this sedimentary succession according to calcareous nannofossils from the Roobiat Village section. Based on the calcareous nannofossil species index, we have detected the NP16 to NN3 zones and subzones which are comparable with the Martini biozonation pattern. Thus, we could suggest a middle Eocene (Bartonian) to early Miocene (Burdigalian) age for this section. Since the studied section contains a complete sedimentary sequence from Paleogene to Neogene systems, as a comparisonal section for the correlation between bio-horizons from western parts of the Tethys basin and its eastern parts, it is recommended.

 Biostratigraphy Biostratigraphy This study was supported by the Department of Geology from the Ferdowsi Univer- sity of Mashhad. Accordingly, the authors are grateful to the Ferdowsi University for supplying the samples and analyses required for this study. We would like to acknowledge the Exploration Directorate of NIOC (Na- tional Iranian Oil Company) for laboratorial facilities provided.

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