DOI: 10.7256/2453-8922.2022.3.38555

EDN: JHLNJJ

Abstract: The purpose of this work was to determine the range of changes in the Fourier criterion (number) when predicting the thermal regime of dispersed rocks in thawed and frozen state. And, also an assessment of the possibility of averaging the thermophysical characteristics of rocks to obtain universal values of Fourier numbers. To achieve this goal, an assessment of the influence of the thermophysical properties of dispersed rocks on the range of changes in the values of the Fourier number used in thermal calculations of technical objects of the cryolithozone is made. The calculation formulas took into account the functional dependence of the coefficient of thermal conductivity, density and specific heat capacity of rocks on humidity (iciness) in the thawed and frozen state. As an example, a mixture of quartz sandstone with water in a thawed and frozen state is considered when the ice content changes from zero (dry quartz sandstone) to full moisture saturation. It is established that the range and nature of the change in Fourier numbers for thawed and frozen dispersed rocks, depending on their humidity (iciness), differs significantly, not only quantitatively, but also qualitatively: for thawed dispersed rocks, the Fourier number decreases with increasing humidity, and for frozen rocks increases. The possibility of averaging the thermophysical characteristics of rocks to obtain universal values of Fourier numbers has been evaluated. It is shown that the use of universal Fourier numbers leads to a significant error for both thawed and frozen rocks and their use in thermal calculations with annual temperature fluctuations is impractical.

DOI: 10.7256/2453-8922.2022.3.38834

EDN: JICZQM

Abstract: Palsas and peat plateaus have an important role in the bio- and geodiversity of Northern environments. The peat of the palsa is an archive of geochemical and biochemical conditions of high quality. The palsa peat bog of Eletsky was studied in the north-east of the Bolshezemelskaya tundra (67°16′ N, 63°39′ E). Palsa of 1.5 to 4 m height were studied in detail. The content of carbon and nitrogen in the peat has been determined, as well as the isotopic composition of carbon. The analysis of the carbon and nitrogen content in plants growing both on the surface of the heave mounds and in the depressions between the mounds was carried out. Variations in C/N values indicate changes in the peat moor humidification regime and the rate of peat decomposition. The results obtained indicate a high degree of watering of the Eletsky massif as a whole during the accumulation of peat and mainly anaerobic conditions of its decomposition. It was found that the change of plant associations also affected the value of C/N. Studies of the Eletsky palsa peat bog have shown that the isotopic composition of carbon is determined primarily by the botanical composition of plant remains. New ecological niches are formed in the process of palsa growth, some plant communities are replaced by others. There was not detected difference of the isotopic composition of thawed and frozen peat.

DOI: 10.7256/2453-8922.2022.3.38895

EDN: JIITKC

Abstract: The main purpose of the paper is to create an optimal strategy for field testing of wedge ice for isotope and radiocarbon analyses. The scientific significance of this task is the need for a detailed isotopic characterization of well-dated sections with ice wedges. The solution of this problem will allow us to obtain a complete isotopic and paleotemperature scenario for the Holocene and the late Pleistocene in the north of Western Siberia, northern and central Yakutia, Chukotka, and the Arctic islands. Reliable ranges of isotopic composition values will be obtained as a result of the application of an improved method of wedge ice sampling. It will give a complete picture of isotopic variations in ice wedges during a certain period of its formation in combination with the age setting of the obtained isotope data. The main provisions of the optimal strategy for field testing of wedge ice for isotope and radiocarbon analyses are formulated. The innovativeness of the proposed technique consists in comparing of oxygen isotope and deuterium curves obtained from two parallel and quasi-synchronous ice wedges exposed by a single outcrop in the yedoma and Holocene deposits. Previously, it was believed that the sampling from different ice wedges in the single outcrop would give the same results. The preliminary studies carried out by the author show that this is not always the case. At the same depths, both identical and noticeably different isotopic determinations were obtained from samples from neighboring ice wedges. Predominantly horizontal sampling from ice wedges in yedoma deposits should still be referred to as an insufficiently developed procedure, it should be supplemented by vertical sampling from ice wedges. It is possible to develop criteria for excluding older 14Ñ dates due to admixture of allochthonous organic material as inversions with vertical sampling only. This is impossible using horizontal sampling.

DOI: 10.7256/2453-8922.2022.3.38689

EDN: JIVEUJ

Abstract: The object of the study are the cryogenic soils located within the Chara valley. We attributed soils in a post-pyrogenic sparse larch forest on the terrace of the Chara River, to the type of gleyzems (Gleysols), subtypes - permafrost cryogenically ferruginized cryoturbated and permafrost cryogenically ferruginized post-pyrogenic. The field diagnostics of these two soils is ambiguous, since the soil profiles contain some morphological features that make it possible to identify them as podburs (Entic Podzols): a bright red color of the BF horizon, a sandy loam texture, containing less than 19% of clay particles (< 10 µm). Field diagnostics, together with laboratory studies, indicate that the soils in the section on the stone run at the top of the Udokan Ridge belongs to peat-lithozem (Histic Leptosols). Chemical analyses have shown that the described soils are acidic with pH ranges from 4.9 to 5.4 and relatively slightly saline, TDS ranges from 8.1 to 18.9 mg/L. The carbonate alkalinity is also relatively low: 2.4–4.8 mmol(-)/100 g of soil. The sections are strongly differentiated by the content of organic carbon. Permafrost peat-lithozem contains from 9.3 to 37.8%, permafrost cryogenically ferruginized post-pyrogenic gleyzem is much less enriched in it, the content here does not exceed 6.8%, usually being around 0.9%.

DOI: 10.7256/2453-8922.2022.3.39001

EDN: GJEIUY

Abstract: The subject of the study are soils on the territory of the Khanovey educational field training site in the Vorkuta district of Komi Republic. Morphological descriptions of soil profiles and diagnostics and classification of soils in the modern Russian system were carried out. Laboratory analysis was carried out to determine soil properties: moisture content, acidity and total content of soluble salines. The study area is located in the southeastern part of the Bolshezemelskaya tundra, it is represented by inclined surface of the right side of the valley of the Vorkuta River valley, composed of alluvial and ancient alluvial sands, overlain by loamy and sandy-loam deposits. Holocene peatlands up to 4–5 m thick are the youngest deposits within the studied territory. Small and large dwarf birch tundras with shrub-green moss and grass-shrub-sphagnum cover are common here. The studied soils belong to the division of organogenic, postlitogenic and synlitogenic soil formation. The first includes oligotrophic peaty soils within a thick peatland (Histosols), the second includes cryogenic and cryometamorphic soils (Cryosols), as well as peaty gleyzems (Histic Cryosols). The third includes alluvial humic soils (Fluvisols). The moisture content of soils varies widely from 2 to 900 %. Soils acidity is from acidic to neutral (pH 4.5 to 7.5). The content of soluble salts in soils varies from about 0 to 300 mg/l.

DOI: 10.7256/2453-8922.2022.3.38777

EDN: HNHLEU

Abstract: The design and construction of highways in the cryolithozone is associated with a number of difficulties, which are determined not only by geocryological and climatic operating conditions, but also by the complexity of the actual forecast of the thermal regime of road coverings and foundations. Many thermal calculations to substantiate technical solutions for the protection of highways in the cryolithozone from negative cryogenic phenomena are based on the determination and selection of a given thermal resistance of the structural layers of the pavement. The purpose of these studies was to assess the feasibility of using equivalent thermal resistance in modeling thermal processes and to determine the error in calculations that we make by replacing the layered pavement structure with an equivalent one.     Simple engineering dependences are obtained that allow us to determine the error in calculations when using equivalent thermal resistance. The calculation of the thermal resistance of the three-layer construction of the pavement is made. It is established that for a three-layer pavement structure, the error value in the calculation of thermal resistance is directly related to the degree of deviation of the values of the thermal conductivity coefficient of the materials of individual layers from each other. Moreover, the parameters of the inequality of thermal conductivity coefficients for individual structural layers when determining the minimum calculation error are functionally related to each other. The results of variant numerical calculations are presented in the form of 3D and 2D graphs, which allow us to visually assess the influence of the studied parameters on the relative error of calculating the thermal resistance of the pavement.