Earth’s Cryosphere, 2022, Vol. XXVI, No. 1, p. 19-31.
TRACES OF CRYOGENIC PROCESSES IN THE LATE PLEISTOCENE SEDIMENTS OF THE PUR-TAZ INTERFLUVE (WEST SIBERIA)
E.A. Slagoda1–3, А.А. Novoselov2, Е.S. Koroleva1, А.О. Kuznetsova1, V.I. Butakov3, Ya.V. Tikhonravova4, E.P. Zazovskaya5
1 Earth Cryosphere Institute, Tyumen Scientific Center, Siberian Branch of the Russian Academy of Sciences, Malygina str. 86, Tyumen, 625026 Russia; eslagoda@ikz.ru
2 University of Tyumen, Volodarskogo str. 6, Tyumen, 625003 Russia
3 Tyumen Industrial University, Volodarskogo str. 38, Tyumen, 625000 Russia
4 Melnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences, Merzlotnaya str. 36, Yakutsk, 677010 Russia
5 Institute of Geography, Russian Academy of Sciences, Staromonetnyi per. 29, Moscow, 119017 Russia
Reconstruction of paleoenvironmental conditions, genesis of sediments, and permafrost evolution, as well as identification of cryogenic and paleocryogenic formations from sediment cores are among key scientific problems of cryolithology. We have analyzed grain-size distribution, geochemistry, and water content of sediments from the permafrost section in the north of the Pur-Taz interfluve (West Siberia). Moreover, we have described the floristic composition of plant remains, their age and the cryostructures found within these sediments. Optical and electron microscopy have been applied to reveal the micromorphological features of thin sections and rock specimens. Based on the sediment core data from the borehole, we have established the alluvial, lacustrine, and colluvial geneses of sediments. Furthermore, we have reconstructed the conditions of sediment deposition in this area and have established the Karginsky age of these sediments. This age corresponds to the third lacustrine–alluvial plain in the lower course of the Taz River. The conditions of the early diagenetic transformation of sediments, as well as epicryogenic and syncryogenic structure types have been reconstructed based on cryogenic and post-cryogenic formations, cryostructures, microstructure, and authigenic minerals. We have also reconstructed the Late Pleistocene sequences of freeze–thaw cycles in the upper part of the permafrost section of the Pur-Taz interfluve.
Cryogenic structure, post-cryogenic formations, genesis, age, composition, microstructure, authigenic minerals of sediments