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Weighting of isotopic composition of ice-wedge casts of Central Yakutia due to active evaporation of surface waters
Abstract.The research object is the isotopic composition of oxygen and hydrogen of ice-wedge casts, surface waters and atmospheric precipitation in Central Yakutia near the Mammoth Mountain, where the conditions are favourable in summer for evaporation and continental salinization of permafrost and subsurface ice. Special attention is given to the analysis of high indexes of isotopic composition of ice-wedge casts of the late Pleistocene, which can’t be explained by higher winter temperatures during the formation of ice wedges. The authors use hydrochemical data showing the signs of continental salinization in the fragments of wedges with heavy isotope composition. The main research method is the definition of isotopic composition of oxygen and hydrogen in the ice. In graphic form, one of the indicators of evaporation is the evaporation line, whose inclination on the dependency diagram δ18Î – δ2Í is around 5. The authors show that continental salinization of the landscapes of Central Yakutia can be explained by the combination of the processes of perennial freezing of sediments and evaporation during summer seasons. The authors design the system of indexes of continental salinization of cryogenic lacustrine-boggy landscapes on the basis of isotopic and hydrochemical data of surface waters and subsurface ice: 1 – abnormal heavy isotopic composition; 2 – isotopic composition indexes are on the evaporation line, whose angle of inclination (usually lower than 5) is lower that the angle of inclination of the global meteoric water line (8); 3 – high salinity of ice-wedge casts and sediments with prevailing continental salts. The obtained results are accurate and can be easily reproduced by any isotope laboratory in the world.
Keywords: continental salinization, alas landscape, ice mineralization, evaporation line, hydrogen isotopes, oxygen isotopes, precipitation, surface water, ice wedge, Central Yakutia
Article was received:25-10-2017
This article written in Russian. You can find full text of article in Russian here .