The Cyclical Structure of the Isotopic Diagram of a Lithalsa and Its Radiocarbon Age, Sentsa River Valley, Eastern Sayan
Tóm tắt
This paper reports on the nature and history of the mineral-rich frost heave mounds—lithalsas—developed on the first terrace of the Sentsa River in Okinsky District of Buryatia. An ice core of the lithalsa was exposed by drilling of a 20-m borehole. The most typical feature of the isotopic diagrams, which we obtained for the ice core, is their cyclical pattern illustrating isotope minima at depths of about 3–5 m, 9–12 m, and 18–21 m, separated by two distinct isotope maxima. Most likely, this demonstrates the cyclicity of the triple flooding of the growing frost heave mound and the subsequent active evaporation of lake-march waters, which are the main source of moisture for the lithalsa ice core. Based on the detailed radiocarbon dating of organic material from the upper horizons of the highest and surrounding lithalsas, we determined the time of their formation. Organic material in drained frost-susceptible soils was intensely accumulated during the period from 0.5 to 0.2 ka BP. This is the time of the beginning of the formation of permafrost, active ice-formation, and the associated frost heave and lithalsa growth. The age of at least three of four mounds studied is not older than 200 years, it coincides with the cooling at the beginning of the 19th century.
Tài liệu tham khảo
S. G. Arzhannikov, R. Braucher, M. Jolivet, A. V. Arzhannikova, R. Vassallo, A. Chauvet, D. Bourles, and F. Chauvet, Quat. Sci. Rev. 49, 16–32 (2012).
Yu. K. Vasil’chuk, S. V. Alekseev, S. G. Arzhannikov, L. P. Alekseeva, N. A. Budantseva, Ju. N. Chizhova, A. V. Arzhannikova, and A. C. Vasilchuk, Permafrost Periglacial Processes 27 (3), 285–296 (2016). https://doi.org/10.1002/ppp.1876
A. A. Svetlakov, Candidate’s Dissertation in Geology and Mineralogy (Irkutsk, 2018).
D. V. Kotelevets and Dzh. Yu. Vasil’chuk, Arkt. Antarkt., No. 1, 122–132 (2018). https://doi.org/10.7256/2453-8922.2018.1.25935
S. V. Alekseev, L. P. Alekseeva, A. A. Svetlakov, E. A. Kozyreva, and Yu. K. Vasil’chuk, Arkt. Antarkt., No. 2, 136–149 (2017). https://doi.org/10.7256/2453-8922.2017.2.23037
S. V. Alekseev and L. P. Alekseeva, Led Sneg 58 (4), 524–536 (2018).
Yu. K. Vasil’chuk, Kriosfera Zemli 15 (3), 51–55 (2011).
J. W. S. Rayleigh, Philos. Mag. Ser. 5 42 (259), 493–498 (1896). https://doi.org/10.1080/14786449608620944
S. A. Harris, in Proc. 6th Int. Permafrost Conf. (Bejing, 1993), Vol. 1, pp. 238–243.
A. J. R. Gaanderse, S. A. Wolfe, and C. R. Burn, Earth Surf. Processes Landforms 43 (5), 1032–1043 (2018). https://doi.org/10.1002/esp.4302
F. Calmels, “Genése et structure du pergélisol. Étude de formes périglaciaires de soulévement au gel au Nunavik (Québec nordique), Canada,” Thése de doctorat (Faculté des études supérieures de l’Université Laval, 2005).
J. A. Eddy, Sci. New Ser. 192 (4245), 1189–1202 (1976).
S. Wagner and E. Zorita, Clim. Dyn. 25 (2–3), 205–218 (2005).