Home – Home – Jornals – Earth’s Cryosphere 2024 number 1

In 1957-1959, according to the program of the 3rd International Geophysical Year, the temperature of rocks (to a depth of 20 m) and glacier ice (to a depth of 45 m) was measured in the area of a high-mountain weather station (glacier no. 31) in the central part of the Suntar-Khayata Ridge (Northeastern Russia). In 2012-2017, the Russian-Japanese expedition carried out new measurements of the temperature of rocks and glacier ice at the same places. A comparison of the data on the mean monthly temperatures of glacier ice at a depth of 10 m in 1958 and 2012 attests to their rise by 1.0-1.6 °С. As there was no possibility to perform direct measurements of rock temperature at a depth of 20 m in 2012 -2017, we used an indirect method to estimate it at the depth of zero annual amplitude. According to our estimate, in the past 60 years, it could have increased by up to 1.6 ° C. Regime studies of the dynamics of seasonal thawing were carried out at four experimental plots; of the dynamics of freezing of the seasonally thawed layer, at one plot .

Results of the study of the regularities of new formation of frozen ground near the southern boundary of permafrost against the background of a positive climate trend are presented. Criteria for the potential formation of permafrost in response to climate warming are established. Results of modeling and quantitative assessment of the newly formed permafrost caused by transformation of landforms during thawing of frozen ground are given with respect to soil drainage and warming effect of the snow cover.

The results of sedimentological analysis of bottom sediments of the Ivashkina Lagoon on the southern coast of Bykovsky Peninsula (southeast of the Laptev Sea) are presented. Core samples from boreholes drilled in the Holocene thermokarst depression now occupied by the lagoon have been analyzed. The use of grain-size distribution data and Passega C-Md diagrams makes it possible to refine the genetic interpretation of the sediments obtained from field descriptions. The Holocene lacustrine-lagoon and taberal formations and the underlying Middle and Late Pleistocene alluvial sediments have been identified, and their grain-size characteristics have been determined. We have further reconstructed the sequence of their formation while a thermokarst depression had been transformed into a lagoon.

The morphology and properties of frozen strata were studied in the area of the largest retrogressive thermal thaw slump Batagay (Yakutia). A presumably continuous stratigraphic sequence of permafrost sediments accumulated during the Middle and Late Pleistocene (~700-11 ka) and was partially transformed during the Holocene. Based on paleopedological, paleontological, and geocryological data, new suggestions have been made regarding the historical development of the soil-vegetation cover and late glacial fauna in the Yana Plateau region. Two extensive and relatively warm climatic periods favoring the formation of developed soil-vegetation cover have been identified: the first one belongs to MIS 15-17 (600-700 ka) or (depending on the dating method) to MIS 7e (230-250 ka); the second one is more certainly dates back to MIS 5e (110-130 ka).

The paper presents the results of studying the appearance and sizes of pockmarks in lakes of three bioclimatic zones of Yamal: northern (arctic), typical, and southern tundra. The diameter of pockmarks in the lakes increases from 1.9 m in the northern tundra to 7.7 m in the southern shrub tundra. Pockmarks occupy from 0.5 to 4.3 % of the shallow-water lake area. The content of methane in lake sediments is two or more times higher than in the sediments of the active and transition layers of dominant landscapes. In the typical tundra zone, the methane content in lake sediments is usually about 7 mL/kg, but in some cases it can reach 18 mL/kg and more. Probably, these are the lakes with the high methane content in bottom sediments, where gas emissions can occur and pockmarks can form. After drainage (drying) of the lakes, lake basins (khasyreys) are subjected to freezing, and the cryogenic structure of lake sediments is formed. Eight-ten years after drying, succession changes in the former lake bottoms continue, and the formation of the transition layer is not yet completed.

The results of modeling the consequences of a hypothetical outburst flood from Lake Dasht (Tajikistan, the Shakhdara River basin) with the use of FLO-2D and FLOVI mathematical models are presented. The discharges of the outburst flood and debris flow and the increment of solid material in the debris flow have been obtained using the FLOVI program. The debris flow movement and accumulation in the valley have been simulated using the FLO-2D hydrodynamic model. The results indicate that the application of data obtained from the FLOVI program with transport-shift equation block in the FLO-2D model gives more correct characteristics of the debris flow, including the values of flow discharge, velocity, depth, and flooding area.

On November 10, 2023, Stanislav Ivanovich Zabolotnik, leading researcher at the Laboratory of General Geocryology of the Melnikov Permafrost Institute, Candidate of Geological and Mineralogical Sciences, Member of the International Academy of Informatization passed away at the age of 86 after a serious long illness. Stanislav Zabolotnik will be remembered as a remarkable permafrost researcher, an experienced field worker, and science manager.