Strontium isotope stratigraphy: Possible applications for age estimation and global correlation of Late Permian carbonates of the Pechishchi type section, Volga River

¹Department of Geology, Kazan State University, Kazan, Russia
²United Institute of Geology, Geophysics and Mineralogy SB RAS, Novosibirsk, Russia

Abstract

[1]  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.

Received 21 May 2007; revised 30 May 2007; accepted 12 June 2007; published 3 August 2007.

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

Index Terms: 0426 Biogeosciences: Biosphere/atmosphere interactions; 1022 Geochemistry: Composition of the hydrosphere; 1041 Geochemistry: Stable isotope geochemistry; 3000 Marine Geology and Geophysics; 9335 Geographic Location: Europe; 9615 Information Related to Geologic Time: Permian.

Citation: Nurgalieva, N. G., V. A. Ponomarchuk, and D. K. Nurgaliev (2007), Strontium isotope stratigraphy: Possible applications for age estimation and global correlation of Late Permian carbonates of the Pechishchi type section, Volga River, Russ. J. Earth Sci., 9, ES1002, doi:10.2205/2007ES000221.