Home – Home – Jornals – Earth’s Cryosphere 2025 number 3

The article presents the results of a theoretical analysis and laboratory studies of the zonality of the multidirectional deformation process of heaving of freezing soils using the example of light sandy loam widespread in the seasonal freezing-thawing layer in Russia. Ideas about the characteristic zones of freezing soil are developed, namely, a cryogenic contraction zone is added, the mechanism of its formation is substantiated, and the role in cryogenic heaving of soils is shown. The results are important for the physical formulation of a mathematical model of freezing and heaving of clay soils, taking into account heat and mass transfer and multidirectional deformations, in relation to the fundamentals of geocryological forecasting of the stability of buildings and structures in the area of distribution of frost-susceptible soils in the cold regions of Russia.

Data from detailed and long-term coastal studies in the Arctic have been utilized to estimate the rates of coastal erosion along the Laptev and East Siberian seas, as well as to reveal the specific features of geomorphological and cryogenic coastal processes. Eroding coastlines are dominant in the study region with erosion rates as high as 25 m per year along the coasts composed of very ice-rich permafrost sediments. The Laptev and East Siberian coastline was subdivided into 123 coastal segments each characterized by specific lithology, coastal morphology, and dynamic regime. It was found that the average long-term rates of retreat of the shores of the Laptev and East Siberian Seas are characterized by the highest rates of destruction in comparison with the shores of all other Arctic seas.

The study examines the chemical composition of spring waters in the central part of the Chara basin and its evolution over the past four decades. The current chemical composition of the spring waters is characterized as magnesium-calcium bicarbonate with total dissolved solids (TDS) ranging from 36 to 162 mg/L and fluorine content varying between 0.01 and 4.0 mg/L. This research presents, for the first time, data on the stable oxygen and hydrogen isotopes in the springs of the “Sands” massif. The isotopic composition of these springs is as follows: δ¹⁸O = (-16.95 ± 0.69) ‰, δD = (-130.20 ± 4.42) ‰, d_exc = (5.40 ± 1.38) ‰. The combined results of chemical and isotopic analyses suggest the involvement of glacial waters from the Kodar mountains in the formation of the springs within the massif. These springs are formed through the mixing of waters from aeolian and lacustrine-alluvial deposits with more mineralized intrapermafrost waters of fluvioglacial deposits. The degree of participation of waters from different aquifers is reflected in the fluorine content and isotopic composition of springs. The first aquifer system waters have a heavy isotopic composition and contain less fluorine (0.4-2.0 mg/L). The waters from the second aquifer system have a light isotopic composition and a fluorine content of 2-4 mg/L or more. Over the past 40 years, a decrease in mineralization, the content of Na⁺ + K⁺, Cl^- and F^- in spring waters indirectly indicates an increase in the share of glacial runoff in their nutrition.

The paper presents actual data of methane content measurements in frozen sediments and ground ice in the western sector of the Russian Arctic, at the sites located from the western coast of Yamal to Western Taymyr. The cryolithological structure of sampling sites is presented, and stratigraphic and genetic complexes of sediments and ground ice are identified. It is shown that the methane content in sediments formed during colder climates is generally lower than in warmer periods. Minor differences are noted in the methane content in sediments of different lithological composition. The methane content in wedge ice of different ages remains almost the same. The methane content in massive ice depends on the origin, composition, and freezing conditions of the enclosing sediments and varies greatly from sample to sample, reaching a maximum of 24 mL/kg.

This paper considers a new design of a super-deep pressure seasonally-acting cooling device, the principle of operation of which consists in the pressure mode of refrigerant flow due to the difference in the density of liquid columns in the gas-liquid mixture. A mathematical model of the system functioning has been developed, which allows estimating many parameters of operation, the key ones being temperatures in the evaporator, mass flow rates and velocities of the refrigerant flow in different phases, as well as the depth of the refrigerant boiling in the evaporator. Numerical experiments have been carried out, which have shown that the model adequately reflects the real operating conditions of the system under significant variation of key external conditions, such as ambient temperature and values of specific heat loads on the seasonally-acting cooling device evaporator. The parameters are determined for different depths of the evaporator part. One of the key performance indicators of the super-deep pressure seasonally-acting cooling device was the maximum refrigerant temperature in the evaporator, which turned out to be the most sensitive to changes in the specific heat load and atmospheric temperature. The dynamics of the refrigerant temperature and its distribution along the length of the evaporator determine the ability to maintain the required frozen ground regime.

In the Middle and Late Pleistocene, in the areas of the source and sink of radiative heat in the Northern hemisphere, the effect of dividing the intensity of seasonal irradiation by phases of changes in the intensity of annual irradiation is manifested. The average values of the intensity of summer radiation in the phase of increasing annual exposure exceed those in the phases of decreasing annual exposure. The average values of the intensity of winter radiation in the phases of increasing annual exposure are inferior to those in the phases of decreasing annual exposure. The effect of phase separation manifests itself in different ways in the areas of the source and sink of radiation heat. In the areas of the heat source, the phase separation of the intensity of summer and winter irradiation, on average, in the stages of high-amplitude oscillations of a  400-millennial cycle exceeds the phase separation in the stages of low-amplitude oscillations. In the areas of radiative heat runoff, on average, the phase separation of the intensity of summer and winter irradiation in the stage of low-amplitude oscillations exceeds the phase separation in the stages of high-amplitude oscillations. The values of the phase separation of the intensity of summer irradiation in the stages of high-amplitude and low-amplitude fluctuations in 5-degree latitude zones vary in different directions, and the intensity of winter irradiation is unidirectional. The phase separation is most noticeable in the area of radiative heat runoff of the Northern Hemisphere (the area of the cryolithozone) in the summer half of the year at the stage of low-amplitude oscillations of a  400-millennial cycle. This is typical for the beginning of the Middle Pleistocene (solar epoch 16), the Likhvin interglacial (solar epochs 8 and 9) and the present (solar epoch 1).

Academician of the Russian Academy of Sciences Vladimir Pavlovich Melnikov celebrates his 85th birthday on July 5, 2025. The main milestones of V.P. Melnikov’s scientific biography are considered. His contribution to the creation of a holistic image of the Earth’s cryosphere and the formation of new directions of cryology is analyzed.