Russian Journal of Earth Sciences Russian Journal of Earth Sciences Russian Journal of Earth Sciences 1681-1208 46994 ОРИГИНАЛЬНЫЕ СТАТЬИ ORIGINAL ARTICLES ОРИГИНАЛЬНЫЕ СТАТЬИ Strontium isotope stratigraphy: Possible applications for age estimation and global correlation of Late Permian carbonates of the Pechishchi type section, Volga River Strontium isotope stratigraphy: Possible applications for age estimation and global correlation of Late Permian carbonates of the Pechishchi type section, Volga River Nurgalieva N G Nurgalieva N G Ponomarchuk V A Ponomarchuk V A Nurgaliev D K Nurgaliev D K Department of Geology, Kazan State University, Kazan, Russia ru Department of Geology, Kazan State University, Kazan, Russia ru United Institute of Geology, Geophysics and Mineralogy SB RAS, Novosibirsk, Russia ru United Institute of Geology, Geophysics and Mineralogy SB RAS, Novosibirsk, Russia ru Department of Geology, Kazan State University, Kazan, Russia ru Department of Geology, Kazan State University, Kazan, Russia ru 9 1 1 8 10 11 2021 https://rjes.ru/en/nauka/article/46994/view

In the present paper the 87Sr/86Sr values have been analysed for the Upper Kazanian regional stratotype section - Pechishchi and accompanied sections of Lower Kazanian and also Lower Permian. The section Pechishchi is unique section formed within the Kazanian palaeosea. It is characterized by three Noinsky's cycles of evaporitization of Kazanian palaeosea. The analysis of received data on 87Sr/86Sr shows that the highest ratios, characteristic of the Asselian, average at 0.70832. In the Artinskian, the 87Sr/86Sr ratios decrease to 0.70774. In the Kazanian, the strontium ratio is much lower: 0.70769 in the Early Kazanian and 0.70740 in the Late Kazanian. The position of received local data on global evolution 87Sr/86Sr curve, in common, is satisfactory. The discrepancies between local and global data observed at some points can be explained by the following: local features of the Permian deposition in the eastern part of the Russian Plate the evaporitic trend and considerable isolation from the ocean; and problems with the chronostratigraphic positioning of the 87Sr/86Sr Phanerozoic evolution curve and local 87Sr/86Sr curves within the Permian. Multiple determinations of strontium isotope ratios in the Permian carbonates and the isotope dating of key samples would allow the revision of the Permian stratigraphic record. Strontium isotope stratigraphy offers an up-to-date and technologically advanced approach to the stratification and correlation of Permian sedimentary sections on both regional and global scales.

In the present paper the 87Sr/86Sr values have been analysed for the Upper Kazanian regional stratotype section - Pechishchi and accompanied sections of Lower Kazanian and also Lower Permian. The section Pechishchi is unique section formed within the Kazanian palaeosea. It is characterized by three Noinsky's cycles of evaporitization of Kazanian palaeosea. The analysis of received data on 87Sr/86Sr shows that the highest ratios, characteristic of the Asselian, average at 0.70832. In the Artinskian, the 87Sr/86Sr ratios decrease to 0.70774. In the Kazanian, the strontium ratio is much lower: 0.70769 in the Early Kazanian and 0.70740 in the Late Kazanian. The position of received local data on global evolution 87Sr/86Sr curve, in common, is satisfactory. The discrepancies between local and global data observed at some points can be explained by the following: local features of the Permian deposition in the eastern part of the Russian Plate the evaporitic trend and considerable isolation from the ocean; and problems with the chronostratigraphic positioning of the 87Sr/86Sr Phanerozoic evolution curve and local 87Sr/86Sr curves within the Permian. Multiple determinations of strontium isotope ratios in the Permian carbonates and the isotope dating of key samples would allow the revision of the Permian stratigraphic record. Strontium isotope stratigraphy offers an up-to-date and technologically advanced approach to the stratification and correlation of Permian sedimentary sections on both regional and global scales.

 strontium isotopic stratigraphy 87Sr/86Sr ratio Permian rocks carbonates evaporates. strontium isotopic stratigraphy 87Sr/86Sr ratio Permian rocks carbonates evaporates.

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