Abstract: This work delineates the macroelements compositions in the Late Pleistocene syngenetic ice wedges (IW-5 and IW-7) situated in the bottom section of the Batagay Yedoma complex. Ice samples were extracted from ice wedges at 10 cm intervals using Makita and Bosch GSR drills equipped with steel ice crowns of 51 mm in diameter. The composition of macroelements in the ice wedges was analyzed using the ion chromatograph "Steyer." The concentrations of potassium, sodium, calcium, magnesium, chlorine, nitrates, and sulfates were measured. The mineralization of Late Pleistocene ice wedges ranges from 67 to 425 mg/L. In the analyzed ice wedges, calcium predominates among the cations (IW-5 ranging from 17.8 to 82.5 mg/L, IW-7 from 12.0 to 52.1 mg/L). Magnesium ranks second (IW-5 ranging from 3.1 to 13.6 mg/L, IW-7 ranging from 2.6 to 8.3 mg/L). Sodium and potassium cations are present in minimal concentrations: Na – IW-5 ranges from 0.8 to 6.8 mg/L, IW-7 from 0.45 to 4.0 mg/L, and K – IW-5 from 17.8 to 82.5 mg/L, IW-7 from 1.1 to 5.6 mg/L. Nitrates dominate among the anions. The nitrate concentration varies from 6.9 to 27.9 mg/L for IW-5 and from 5.0 to 54.8 mg/L for IW-7. Mean nitrate concentration IW-5: 14.5 mg/L; IW-7: 12.2 mg/L. In IW-5, the concentration of sulfate anions ranges from 2 to 17 mg/L, with an average of 6.4 mg/L, whereas the chloride concentration ranges from 1.08 to 7 mg/L, averaging 2.6 mg/L. The sulfate concentration in IW-7 ranges from 1.4 to 40.5 mg/L, with an average of 5.79 mg/L; the chloride concentration ranges from 1.13 to 4.5 mg/L, with an average of 1.96 mg/L. In IW-5, the chloride-to-sulfate ratio ranges from 0.16 to 1.45, with an average of 0.44; in IW-7, the ratio ranges from 0.04 to 1.12, with an average of 0.47. Upon comparing these data with the chloride to sulfate ratios in ground ice and surface water in North-West Siberia, we observe that the ratios most closely resemble those found in the snowfields of the Seyakha (Mutnaya) River valley on the northern Yamal Peninsula, where the chloride to sulfate ratio is 0.54, in rainwater on the Yamal Peninsula with a ratio of 1.44, and in segregated ice on the first terrace of Bely Island, where the ratio is 1.08. The chloride to sulfate ratio in IW-5 and IW-7 significantly differs from that of cryopegs (ratio 49.45) and the majority of the massive ice in the Yamal Peninsula (68.91; 26.39; 9.77, etc.).
The ionic composition of the ice wedges indicative that they was formed from thawed snow generated under the influence of continental air masses.

Abstract: The subject of the study is the cryostructures of Pleistocene sediments uncovered by a 30-m borehole in the Churapcha village and the distribution of stable oxygen and hydrogen isotopes in the schlieren ice and thin ice lenses. The research was located in the area of continuous permafrost distribution, the vertical thickness of which reaches 400–500 m here. The average annual temperature of rocks ranges from -4.6 to -6.2 °C, in river valleys the temperatures are increased to about –2 to –1°C. Permafrost sediments in the Churapcha area are characterized by relatively high iciness, from 26 to 47%. Ice is found in deposits as interlayers that form a layered (as well as lenticular and braided) cryostructure. During the fieldwork, frozen cores opened by a drilling hole at a depth of 30 meters were studied. Drilling was carried out using a large-sized drilling rig (PBU-2) based on a Kamaz truck. A core drilling pipe with a diameter of 146 mm was used. Sampling was carried out from the frozen core. The well-uncovered permafrost deposits, which have mainly dark brown and gray colors, especially bluish-gray shades characteristic of heavy loams and clays. The seasonally active layer has a sandy loam composition, and below, at depths from 1.5 to 6.0 m, the deposits are loamy. At depths of 6.0–20.0 m, alternating layers of loams and clays of different thickness are observed, and below there is a sharp change in the lithological composition to medium and fine sand (20.75–24.0 m), including a large number of layers of organic matter. The distribution of δ18O and δ2H values was examined in structured ice up to a depth of 17.7 meters. In the upper 12 m, the isotopic composition is significantly more negative: δ18O values vary from –29.44 to –34.35‰, while δ2H values range from –213.5 to –253.6‰. In the 12-17.7 m range, δ18O oscillates between –25.94 and –28‰, whereas δ2H ranges from –195.3 to –214.3‰. Analysis of data on the isotopic composition of structure ice in the yedoma deposits of Yakutia showed a close range of values with the ice of unit 1 from the borehole in Churapcha that we studied. The heavier isotopic composition of ice of unit 2 is probably explained by another source of water and the influence of isotopic fractionation during the interaction of clay particles with water. As for the contrast of the isotopic characteristics of unit 1 and unit 2, we note that such a ratio, when the isotopic composition in the upper unit is on average consistently 3-5‰ lower than in the lower unit, is quite rare in permafrost.
The water for the formation of segregation ice from the borehole could have been formed to a greater extent from melted winter snow and was less subject to evaporation. Contrasting values in the ice of the two studied units may indicate different water sources; for the ice in unit 1, the water source could have been, to a greater extent, winter precipitation (surface water formed from melted snow); the presence of a negative peak in the vertical distribution of isotopic values may indicate two-sided freezing (from above and below) and isotopic fractionation during freezing.
The deposits of unit 2 are represented by heavy loams, probably lacustrine. It can be assumed that the saturation of these deposits under these conditions occurred with lake water, which consisted of a mixture of precipitation from both winter and summer seasons and was characterized by higher values of the isotopic composition. Freezing of these loams could have begun already when the lake became shallow. In any case, for now the probable explanation for the heavier isotopic composition of unit 2 is isotopic fractionation in water during interaction with clay particles and a different water source than in unit 1.

Abstract: The subject of the study is the ionic composition of syngenetic Late Pleistocene ice wedges: IW-17 and IW-20, located in Batagay yedoma. Both ice wedges consist of ultra-fresh ice with concentrations of major ions from 20 to 40 mg/L. For samples from ice, a method was used to measure the mass concentration of Ca2+, Mg2+, Na+, K+, NH4+ cations in samples of drinking, mineral, natural and waste water by ion chromatography FR.1.31.2005.01738. The range of detectable concentrations is 0.10-20.00 mg/L, and for the determination of anions, the method of measuring the mass concentration of Cl-, SO4-, NO3- in samples of drinking, mineral, natural and wastewater by ion chromatography FR.1.31.2005.01724 was used. The range of detectable concentrations is 0.10-20.00 mg/L and the method of measuring the mass concentration of ions in samples of natural, drinking and wastewater by ion chromatography HDPE F 14.1:2:4. 132-98 was used, the range of detectable concentrations for cations is 0.10-150.00 mg/L. Measuring instruments: ion chromatographic system "Stayer", detection limit for chloride ion 0.02 mg/L.
The main results of the conducted research are, as follows:
Sodium and calcium soluble cations significantly predominate in the ionic composition of IW-17, reaching 24.15 and 53.16 mg/L, respectively. In the same sample, chlorine anions reach 34.51 mg/L. The average concentration of sulfate soluble anions is 2-3 mg/L.
Sodium and calcium cations significantly predominate in the ionic composition of IW-20, reaching 7.27 and 50.0 mg/L, respectively. In the same sample, chlorine anions reach 13.72 mg/L. The average concentration of sulfate anions is 2-4 mg/L, reaching 22.24 mg/L. The content of calcium soluble cations is 6-20 mg/L (calcium soluble cations rarely reaching 42-53 mg/L), the concentration of potassium cations is 0.7-3 mg/L.
Sodium and calcium cations significantly predominate in the ionic composition of IW-20, reaching 7.27 and 50.0 mg/L, respectively, in one sample. In the same sample, chlorine anions reach 13.72 mg/L. The average concentration of sulfate anions is 2-4 mg/L, reaching 22.24 mg/L. The content of calcium soluble cations is 6-20 mg/L (rarely reach 42-53 mg/L), the concentration of potassium cations is 0.7-3 mg/L.

Abstract: The article aims to ascertain the qualitative and quantitative ion composition of three massive ices in the central and southern regions of Yamal: a) Bovanenkovo, situated on the shore of Lake Hanikoshito; b) in the upper reaches of the Mordyyakha River; and c) in the Erkutayakha River valley. We compared the results with the ionic composition of the known massive ice of the Yamal Peninsula (Bovanenkovo, Kharasavey, Marre-Sale, Neito, Yuribey, Sabetta) and adjacent territories (Gyda, Tanama, Ust-Port, Ledyanaya Gora) to identify the genetic similarity of the three studied massive ices, thereby establishing a more definitive nature. Samples from all three massive ices are ultra-fresh, with ion concentrations ranging from 20 to 40 mg/l. In the ionic composition of the Bovanenkovo massive ice, sodium cations noticeably predominate, reaching 38.95 mg/l in turbid ice and potassium cations up to 21.76 mg/l in highly bubbly transparent ice. Sodium cations noticeably predominate in the Mordyyakha River valley, reaching 68.51 mg/l in ice with soil and 6.1 mg/l in crystal ice. In the ionic composition of massive ice in the Erkutayakha River, approximately equal amounts of sodium cations are observed, reaching 3.64 mg/l. The average concentration of chlorine anions in the massive ice of the Erkutayakha River valley varies: in crystal and milky white ice, 0.76 mg/l; in gray ice of horizontal layers, 1.46 mg/l; and in vertically layered ice of the central stock, 1.48 mg/l. The ionic compositions found in the three thick massive ice lenses that were studied are most similar to those found in Holocene intrasedimental massive ice lenses near Sabetta village and infiltration-segregation thick ice lenses near Gyda village. This is the basis for the classification of the studied massive ice as intrasedimental massive ice.

Abstract: The study's focus is on the distribution of oxygen and hydrogen isotopes in the ice cores of frost blisters in the Chara River valley, Transbaikalia. The Kodar and Udokan mountain ranges surround the Chara Depression. Cryogenic (frosty) heaving is common in high humidity areas with loamy, clay, and peaty sediments. In summer 2023, the authors described two seasonal frost blisters in swampy, forested depressions on the periphery of the Charsky Sands (in the so-called thermosuffusion funnels). Oxygen and hydrogen isotopic compositions of oxygen  (δ18O) and hydrogen (δ2H) in blister ice were analyzed. It has been established that seasonal frost blisters are formed mainly due to downward freezing of the water-saturated active layer sediments, but in some cases, ice was formed as well due to upward freezing from the lower boundary of the active layer. The vertical distribution of the isotope values, as well as the δ2H-δ18O ratio in ice, indicates a relatively rapid freezing of water in closed system conditions during one cycle of freezing. In the ice layers sampled horizontally, very similar isotopic composition values were obtained (for example, in blister ice 1, δ18О values ranged from –17.51 to –17.32‰), which indicates consistent horizontal freezing of ice layers. The slopes of the δ2H-δ18О ratio lines for blister ice are 5.82 (blister ice 1) and 5.95 (blister ice 2). A decrease of the δ2H and δ18О values of blister ice on frost mounds with depth and a slope of the δ2H-δ18O ratio line less than 8–7.3 indicates water freezing under closed system conditions during one cycle without moisture inflow. The distribution of isotopic values in the blister ice of seasonal frost mound 2 may indicate simultaneous bilateral freezing of the water volume.

Abstract: Aufeis is one of the most dangerous natural phenomena. The negative impact of aufeis is determined by the unexpected flooding of the territory and subsequent freezing of water, the formation of ice barriers, the icing of underground structures and communications (mines, tunnels, culverts, and sewer wells), as well as the icing of roads and railways, coastal hydraulic structures, etc. There are cases when explosions of aufeis mounds produce catastrophic disturbances within a few seconds. The aufeis that forms annually in the valley of the Buluus Creek is one of the most famous and studied aufeis of Central Yakutia. The aufeis was sampled from a vertical section. The aufeis is layered, and the thickness of the layers is 3-10 cm. In the upper part of the aufeis, the ice layers are thicker than in the lower.
Sampling from the aufeis ice was carried out using a 5.1-cm-diameter steel crown driven by a Bosch electric drill. Measurements of the isotopic composition of oxygen and hydrogen in ice were performed using a Picarro L 2130-i laser isotope analyzer. The isotopic composition of the Buluus ice varies in a narrow range: δ18O values vary from −20.2 to −21.9‰, δ2H values vary from −159.5 to −173.7‰. Generally, the ice is isotopically slightly enriched compared to the surface water of the Ulakhan-Taryn creek, where the δ18O value is −22.18‰ and the δ2H value is −175.1%. Groundwater is isotopically close to the creek water; its isotope composition is also isotopically enriched compared to the ice of the aufeis, with δ18O values varying from −22.17 to −22.25‰ and δ2H values varying from −173.7 to −175.1‰.

Abstract: The second decade and the beginning of the third decade of the XXI century in yedoma research were characterized by a variety of high-precision measurements of gas inclusions, molecular biomarkers, and DNA. The purpose of this paper is to analyze the most notable publications of 2010–2023 devoted to radiocarbon dating and stable isotope studies of yedoma in the Russian and North American Arctic. AMS dating and stable isotope analysis continued at Lomonosov Moscow State University (Yu.K. Vasil’chuk, A.C. Vasil’chuk, N.A. Budantseva, I.D. Streletskaya, Ju.N. Chizhova, J.Yu. Vasil’chuk), especially detailed on the yedoma of Batagay, Seyakha, Kotelny, and Faddeevsky islands. Active research was continued by the participants of the Russian-German expedition (A. Yu. Derevyagin, A. I. Kizyakov, S. Wetterich, T. Opel, J. Strauss, G. Grosse and L. Schirrmeister) on the yedoma sections of the New Siberian Islands. They studied the Batagay yedoma together with J. Murton and K. Ashastina. Researchers from the University of Fairbanks (M. Kanevskiy, Y. Shur, M. Jorgenson, and E. Stephani) studied in detail the yedoma of the Itkillik River valley, as well as new yedoma sections in the Fox Tunnel, where radiocarbon and isotope studies were also carried out by M.S. Lachniet and A. Sloat from the University of Las Vegas. Research has begun on molecular biomarkers and DNA (E. Willerslev, T. Jørgensen) in yedoma. The study of PAHs in yedoma ice wedges has also begun (Yu.K. Vasil’chuk). It is emphasized that isotopic data is not an end in itself for research; the next step, paleotemperature reconstruction based on these data, is necessary and logically justified. The accuracy and reliability of the proposed paleotemperature-isotope equations are considered.

Abstract: The purpose of the paper is to establish the range of variability of mineralization and ionic composition of water-soluble salts in ice wedges of different ages near the Seyakha village (Eastern Yamal Peninsula) in outcrops of the river floodplain, Holocene peat bog and yedoma, as well as to establish the contribution of atmospheric nutrition of ice wedge and structure-forming ice. In the ice wedge of the yedoma the total mineralization is very variable from 17 to 309 mg/l, which indicates the participation of Ob Bay waters in addition to atmospheric waters. Sometimes there is a noticeable presence of sea salts in the sediments of the floodplain at the mouth of the river, associated with the influx of Ob Bay waters during surge surges of the bay level in the mouth of the river. It has been revealed a noticeable change of the mineralization of structure-forming ice in the Holocene peat, its regular gradual decrease from bottom to top is from 576 to 18 mg/l. This indicates that the reason of the lacustrine-marsh basin (or rather, several small basins) formation was the thawing of large masses of highly mineralized segregated and pore ice contained in the upper part of the lagoon-marine terrace. As the peat bog accumulated, the role of atmospheric precipitation increased, and in the final phase of ice formation in the upper part of the peat, atmospheric precipitation completely dominated.

Abstract: The subject of the study is the content of iron compounds and their radial differentiation in the profiles of cryogenic soils of the Chara River valley (Transbaikalia). The studied soils belong to post-pyrogenic permafrost gleyzems, the depths of the seasonal active‐layer of these soils are from 34 to 44 cm. Macronutrient concentrations, with the exception of Si, rarely exceed 5.0%, while the silicon content reaches 24.3%. Si is also characterized by removal from the upper part of soil profiles and accumulation in permafrost soil horizons. The highest concentrations are characteristic in the O horizons (Mg – 4.8 and Ca – 1.5 mg/kg) for a significant part of the macroelements. The trace elements, Sr and Zr are distributed vary contrastingly (from 5.0 to 29.7 and from 5.6 to 47.1 mg/kg). Values of the R coefficient from 0.3 to 0.9 indicate the initial stage of post-pyrogenic restoration of soil properties, and the active accumulation of Mg, Ca, Ti, Fe, Sr, and other elements in the upper part of oxidized-gley permafrost gleyzem observed in the profile is a sign of active restoration. The soils contain about 3.4% iron, which more than 60–75% is the silicate group of compounds (Feс). The moisture content of soils and the prevailing reducing environmental conditions contribute to the formation of monotonous distributions in their profiles, and in soils without signs of stable hydromorphism, permafrost horizons contain almost 2 times more Feox and Feextr.

Abstract: The first decade of the 21st century in the study of yedoma marked by the widespread use of AMS radiocarbon dating on microinclusions extracted directly from the ice wedge. These studies, together with a detailed study of stable isotope composition, were carried out at Lomonosov Moscow State University (Yu. Vasil'chuk and A. Vasil'chuk) on yedoma sections of Western Siberia, the lower Kolyma, Central Yakutia, together with specialists in the radiocarbon dating: J. van der Plicht, J.-Ch. Kim, H. Jungner, L.Sulerzhitsky. Isotope study of Yedoma sections on the right bank of the Yenisei Bay was begun (A.Vasiliev, E.Gusev, I.Streletskaya and others). During this period, active isotope and radiocarbon studies of yedoma began by the participants of the Russian-German expedition (A.Andreev, A.Chizhov, A. Derevyagin, G.Grosse, H.-W.Hubberten, L. Schirrmeister, S. Wetterich etc.) in the Anzhu Islands, the Lena Delta, and Arctic coast of Western Yakutia. In Chukotka, yedoma was studied by researches of the Anadyr station (A.Kotov). Researchers from the University of Fairbanks (M.Kanevsky, Yu.Shur, H.French, M. Bray and others) continued to study the Fox Tunnel as well as northern Alaska yedoma. Radiocarbon dating, the study of mammoth fauna, and stable isotopes were started by Canadian scientists (C. Burn, D.Froese, G. Zazula and others) on the Yukon yedoma. The study of Paleolithic sites in the yedoma sections were started of the Yana River and the New Siberian Islands (V. Pitulko, E. Pavlova etc.)

Abstract: The subject of the study is the soil-geochemical features of cryogenic mid-taiga landscapes of the Vilyuy River valley in its middle course, located near Mahatta and the village of Kysyl-Syr of the Republic of Sakha (Yakutia). Morphological descriptions of soil profiles were compiled. Chemical and analytical laboratory work was carried out in order to establish the values of the physico-chemical parameters of soil horizons - pH, the content of easily soluble salts, the content of organic carbon, granulometric composition, fractional composition of iron. The main aspect of the soil-geochemical properties of the landscapes of the middle Vilyui River is the gross chemical composition of cryogenic soils. The gross contents of chemical elements were determined by X–ray fluorescence using portable X-ray diffraction, after which the geochemical coefficients of radial (profile) and lateral (catenary) differentiation of concentrations of chemical elements R and were calculated. In automorphic soils, most of the chemical elements are removed from their surface organic horizons, and in mineral ones they are concentrated. Ca, Ti, Mn, Fe, Zn and Zr differ by the highest values of the coefficients R (R reaches 20). The radial differentiation is significantly influenced by acidity, organic carbon content and other soil properties, for example, the increased content of Si, Ca, V and Zn (R up to 1,3–3,7) relative to the horizon of soil parent rocks which is associated with the content of Sorghum. In terms of lateral differentiation, most of the studied elements are characterized by accumulation in the upper part of the soil-geochemical catena. The catenae Ca, Mn, Fe, Zn and Y are most widely distributed in soils (LCa = 0.3–1.8; LMn = 0.1–2.0; LFe = 0.6–2.1; LZn = 0.9–2.9 and LY = 0.3–1.4).

Abstract: The subject of the study was the soil and geochemical features of southern tundra cryogenic landscapes on the Khanovei educational and scientific field site located nearby the eponymous settlement in the Vorkuta district, Komi Republic. Morphology of soil profiles were described according to the modern Russian soil classification system. Chemical analytical sample treatment was done to evaluate such physical and chemical parameters of soil horizons as the pH rate, water-soluble salts content, organic carbon content, soil texture, iron fractional composition. The main point among soil and geochemical features of the Khanovei field site was gross chemical composition of cryogenic soils. Gross concentrations of chemicals were measured with the X-ray fluorescence method by portable X-ray Fluorescence Analyzer and then geochemical ratios of radial (profile) and lateral (catenar) differentiation of chemical elements – R and L. Largest R ratio meanings in soil profiles were in gleyic horizons including above-permafrost. Peat horizons without traces of soil mineral fraction were depleted with the most of elements (R = 0,1–0,3) and mineral horizons of soils were differed by increased RFe, RMn etc. The lower part of the catena with soils of mostly sandy texture was depleted by the main part of elements (Ti, Zn, Zr etc.) and predominantly loamy-textured soils in the upper part accumulate these elements and form increased L ratio meanings.

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%.

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 14С dates due to admixture of allochthonous organic material as inversions with vertical sampling only. This is impossible using horizontal sampling.

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.

Abstract: The object of the study is the isotope composition of three aufeis (icing) in the Viluy River basin. Two of the three tested icing were located in the wide valleys of the streams-tributaries of the Viluy River, one on the flat bottom of the thermosuffusion sinkholes. The areas of studied icings did not exceed 30 sq. m., their thickness ranges from 45 to 100 cm. Stratification is recorded in the icings. The co-isotope diagram δ2H-δ18O shows that icing ice was formed from spring water and generally is isotopically “lighter” compared to the water of Kysyl-Yurekh stream and Viluy River. The isotope composition of the icing ice varies in a very narrow range: a) for icing 1 δ18O values vary from –19.3 to –20.9‰, δ2H values vary from –156.5 to –162.9‰; b) for icing 2 δ18O values vary from –19.7 to –22.4‰, δ2H values vary from –153.2 to –173.1‰; c) for icing 3 δ18O values vary from –19.8 to –22.7‰, δ2H values vary from –162.9 to –181.3‰. The similarity of the isotope profiles of icing 2 on Viluy and icing IB93-5 on Baylot Island and isotope profiles of icing 3 on Viluy and icing F192-6 on Baylot Island was noted, however, the scale of isotopic variations for icings on Baylot Island are 5-6 times greater than that of Viluy icings.

Abstract: The research of peat and peat-mineral frost mounds was carried out in September – October 2021 in the northeast of Yamal Peninsula, 50 km north of the village of Tambey. Morphometric data was acquired om ten frost mounds. The wells with the depth of up to 1 m were drilled in 4 out of 10 mounds using electric drill, which outcropped the upper horizons of permafrost. Descriptions were given to seasonally thawed layer and drilled permafrost. Diameter of the mounds located in various landscape conditions varied from 4.5 to 9.8 m, and their heights ranged from 0.5 to 1.5 m. The thickness of seasonally thawed layer on these mounds varied from 28 to 131 cm, while the maximum depth of seasonal thawing was reached on the slope of the hillock, with rare exceptions when it was observed on the top of the hillock, or 1 meter from it. The steepness of hillocks rarely reached 10°, averaging from 3°to 5°. The seasonally thawed layer consisted mostly of the layers of lignite of varying degree of decomposition, rarely replaced by light gray loam (including peaty). Permafrost rocks were also represented by peat with high content of ice.

Abstract:  
The subject of this research is the assessment of changes of the isotopic composition of ice wedge as a result of self-diffusion. The author offers a relatively simple method of considering the impact of the process of self-diffusion upon redistribution of paleo-isotopic composition that allows accurately and quickly estimating the changes in the values δ18О and δ2H values in ice wedges at different periods of the quaternary (1000 years, 10,000 years, 100,000 years, and 1,000,000 years). The patterns of diffusion process in physico-chemical systems are described by two differential forms of Fick's diffusion laws, which are transformed into Gaussian integral, using six-digit Chambers charts for calculation of the threshold values δ18О. The article applies the experimentally determined real values of self-diffusion coefficient in the ice – D=(2–10)×10-15 m2/s. The values of the Gaussian integral are calculated for time intervals, at different distances between samples with different concentration; for the period of 1,000 years its values in all cases exceed 0.99. For longer time intervals, these values change significantly. The calculated probabilistic values of changes in the concentration of heavy oxygen isotopes in ice wedge under the impact of self-diffusion at different distances and concentration gradients are noticeable only for the time period of over 100,000 years.
 

Abstract: The object of this research is the cryogenic soils of the territory located in Central Yakutia, in the middle reach of Vilyuy River nearby Makhatta Tukulan with middle-taiga larch woods landscapes. In July 2021, on the right and left banks of the Vilyuy River, twelve soil sections have been formed, which relate to turf-podzols and turf-sub-units of the illovial-ferruginous, sod and alluvial sod, psammozems and stratozems according to to classification and diagnostics of Russian soils (2004). On the slope of the river valley was also formed the soil catena that included elementary geochemical landscapes of river terraces tops and slopes surfaces, as well as middle and high floodplains on the slopes of thermofusional funnels. Soil sections were also formed in flooded beam bottom and well-drained ravine bottom, on sub-horizontal Makhatta Tukulan surface, bottoms and  slopes of thermo-suffosional funnels. The study involves 46 soil samples for measuring the acidity level (pH), electric conductivity (EC), and concentration of total disolved solids (TDS). The explored soils are characterized with pH ranging from 2.81 to 7.78, with most common fluctuations of 5.5–5.6. TDS rates were often within the limit of 10 mg L-1 and rarely exceeded that threshold, however, there were single valyes higher than 50 mg L-1. Thus, the highest EC values (over 100 μS/cm) were measured in surface and subsurface horizons with high organic matter content, whereas mostly mineral horizons had typical EС values within the limit of 20 μS/cm.

Abstract: The subject of this research is the composition of micro- and macro- rare earth elements in the Late Pleistocene syngenetic ice wedges of the Seyakha yedoma, explored in the outcrop of the Gulf of Ob in the east of Yamal Peninsula (70°9'27.88 "N, 72° 34'8.31" E), north of the Western Siberia. The All-Russian Scientific-research Institution of Mineral Resources after named N.M. Fedorovsky examined the composition of chemical elements in the ice wedges using the methods of atomic-emission spectrometry and mass spectrometry with inductively linked plasma (spectrometers Elan-6100, Optima-4300DV, Perkin-Elmer, Polyvac E-1000, Rank Hilger).
The following conclusions were made:
1) Ice wedges of the Seyakha yedoma are rich in macro - and microelements was recorded, which exceeds such in ice wedges of Yakutia by 8-10 times. The high composition of microelements indicates the role of aerosol and soil particles in the formation of chemical composition of ice. The differences between the ice of Yamal and Northeastern Yakutia also testify that the chemical composition reflects the involvement of marine aerosols in ice formation.
2) Rare-earth elements accumulate in the ice of Seyakha yedoma. The composition of all rare-earth elements exceeds the Clarke number in river waters by 69 (Tm ) – 382 (Y) times.
3) Variability of microelement composition within the ice wedge is insignificant, which implies that the water of the polluted with dust and aerosols spring-summer snow is filtered through the entire snow layer and is partially cleaned prior to getting into the ice-break in the ground under the snow.

Abstract: The subject of this research is the syngenetic ice wedges stripped in the Batagaika crater (67°34 '49" N, 134°46 ' 19 " E), located 10 km southeast of the Batagay settlement. The assessment of macroelement composition of ice was conducted using “Stayer” ion chromatograph (Russia), the chloride ion detection limit is 0.02 mg/l. The article examines the ionic and macroelement composition of ice in suspended and dissolved forms in the Late Pleistocene syngenetic ice wedge of the Batagay yedoma. A comprehensive geochemical research of the Batagaika crater is carried out for the first time. The author explores the upper and lower ice wedges of different age. The main conclusions are as follows: 1) mineralization of Late Pleistocene ice wedge of the Batagay yedoma ranges from 66.56 to 424.8 mg/l, from ultra-fresh to slightly salted; by ionic composition, the ice is bicarbonate-calcium and corresponds to the snow formed under the influence of continental air masses; 2)  the share of Ca contained in the dissolved form does not exceed 20-30%’ as far as other elements, the share of Mg, K, Na, Al, Fe, Mn in the suspended form is over  90%; 3) by mineralization, the Pleistocene ice of Batagay yedoma coincides with the previously studied Pleistocene ice wedges of Yakutia and the Interior Alaska.

Abstract: The subject of this research is the soils and soil-geochemical catenae in the area of Yeletsky settlement, located in the northeast of the Komi Republic. Catena were deposited on the mound covered with moss-shrub tundra transect from the interfluve of Usa and Yelets Rivers to a lacustrine depression, complicated by arching permafrost mounds. Within the district of research, the authors laid five soil incisions (EL20-P1, EL20-P2, EL20-P3, EL20-P4 and EL20-P5) that formed a soil-geochemical catena along the slope. Complex land cover found at the periphery. The explored soils were formed on silty loams with permafrost horizon at a depth of 0.5-0.7 m and belong to Cryosols, Turbic Cryosols and Histic Gleysols. Cryosols in the upper part of catena show specific cryogenic granular structure due to lack of soil moisture content. The soils on the slope and in the depression are more saturated with water; therefore, structureless Turbic Cryosols and Histic Gleysols are formed. In the soil horizons, the values of pH and electrical conductivity were measured, the content of organic carbon and soil texture were studied. An increase in soil acidity on organogenic zones by 4.3 - 5.7 was noticed; in underlying horizons the pH values reach 6.9.

Abstract: Polycyclic aromatic hydrocarbons (PAHs) are the ubiquitous organic pollutants. They are formed as a result of incomplete oxidation of organic substance, for example, technogenic fuel combustion, heating system, wildfires, volcanism, and decomposition of organic residues. Special attention is given to pyrogenic factor of the formation of PAHs in soils. The subject of this research is PAHs in the soils of Batagaika thermoerosive carter in Northern Yakutia in Verkhoyansky Ulus in Yakutia. The author examines the peculiarities of two soil sections (indices B-VG-2019/1 and B-VG-2019/3). Both soils are post-pyrogenic and contain visible traces of a recent fire: embers are found in subsurface horizons of the examined sections, which indicate the recent fire. The following conclusion were formulated: 1) in soils, dicyclic PAHs account for 93%, while the proportions of tricyclic and tetracyclic compounds are roughly equivalent (4% and 3%, respectively); 2) the average values of individual PAHs in the upper (up to 30 cm) and lower (deeper than 30 cm) horizons differ. In the upper horizons, their total concentration is 27 ng/g, while in the lower horizons it is 14 ng/g; 3) in this case, the key biomarker of fires is naphthalene and its homologues. The absence of PAHs with considerable molecular weight most likely testifies to the relatively low fire intensity. The highest values of C/N ratio are noted in the bedding horizon: 10.89 and 3.31, and the lower soils are characterized with approximately 1, which is substantiated by the low content of carbon and nitrogen in the soil profile.

Abstract: The subject of this research is the soil and catena soils in the area of Batagaika crater located in Verkhoyansk District of Northern Yakutia. Soils are usually represented by Cryosols Gleyic and Podzols Entic, which are formed on eluvial and eluvial-deluvial deposits under larch forests. Exploration of soils was carried out in 2017, 2018 and 2019. On the slope to the Batagaika crater is the soil-geochemical catena, which included the ridge-top surface of the slope of Kirgilyah Mountain, the middle part of the slope, as well as levelled surfaces of Batagaika crater. Soil types are described in accordance with the classification of soils of Russia (2004) and the World Reference Base of Soil Resources (2014 WRB). The following conclusions were made: 1) The soil cover in the area Batagaika crater features various types of soils formed on the permafrost rocks, mainly Cryosols Gleyic, found in various landscape conditions, and Podzols Entic are also sporadically distributed in the area. On alluvial deposits in the valley of the Batagaika River may develop Podzols Haplic. Leptosols Lithic are confined to the elevation of the relief with bedrock located close to the surface; 2). The main processes typical for soils in the area of Batagaika crater are: cryogenic structuring, organic matter accumulation, coarse--humus accumulative processes, gleyification; 3) Nearby the horizon of permafrost rocks in the area of Batagaika crater is marked a local minimum of PH level in Podzols and Cryosols.

Abstract: This article demonstrates the evolution of representation on syngenetic formation of frozen strata set by Lopatin, Abolin, Leffingwell and Nekipelov. It is underlined that the theory of syngenesis is substantiated by the works of Gallwitz, Popov and Katasonov. It is mentioned that Dostovalov proposed a method for approximate determination of the age of ice-wedge ice and calculated that 3m wide ice wedges in the vicinity of Abalakh Lake are older than 2160 years, and 30-40 m high ice wedges in the Novosibirsk islands are older than 12,000 years according to Dostovalov’s calculations. The subject of the detailed study is the meso- and macro- cycles in the structure of yedoma strata in Northern Yakutia. Mesocycles in the yedoma strata of the Zelyony Mys, Stanchikovsky Yar, and Batagay have been examined, along with macrocycles of the Batagay yedoma. The mesocyclicity of the cryolithogenic strata is analyzed in the following cross sections: in Bolshoy Lyakhovsky Island, yedoma in the Belyanka River valley, in the outcrop Soplivaya Gora in the Yana River valley, in the valley of the Vilyuy River downstream of Verkhnevilyuysk, etc. The duration of the mesocycles formation in the yedoma strata of the Northern Yakutia is established: a. One subaquatic-subaerial mesocycle in the Zelyony Mys yedoma consisting of a subaquatic sandy loam and a subaerial peaty horizon of 4 m thick accumulated over the period 3,000years. b. One subaquatic-subaerial mesocycle in the Stanchikovsky Yar yedoma 5 m thick accumulated over the period of 3,300 years. c. One mesocycle in the section Soplivaya Gora, in the Yana River valley with a capacity of 3 m formed for about 3.000 years. Three macrocycles are identified in the Batagay section, with capacity of 7, 10 and 40 m; the time of formation of each macrocycle varied from 15-20 to 40 thousand years or more.

Abstract: Massive ice is widespread on the territory of modern of Eurasian permafrost area: in the north of Western Siberia, Taimyr, Chukotka, and Arctic islands. Their thickness reaches 45-50m. The origin of massive ice is difficult to define due to the equifinality of such two different processes as intrasedimental freezing and formation of glacial ice. In both cases, thick massive ice is formed in various ways, but with the same final appearance. Three important aspects that show the evidence of the intrasedimental origin of massive ice in the north of Eurasia are examined. At first glance, they are obvious, but still fell out of sight of paleogeocryologists. It is shown that: 1) Any currently existing Late Pleistocene glacier, or part of it located under Holocene ice, have not yet been found within the Eurasian Arctic or on the Arctic islands with ice sheets, nor in the mountainous regions. 2) The isotopic composition of the vast majority of massive ice found in northern Eurasia is quite "Holocene", whereas in the north of Canada and Alaska, ice with a very light isotopic composition can often be found. 3) It should be taken into account that massive ice is found in the Holocene sediments of Western Siberia and Chukotka, where there is no reason to assume the glaciers spread to the plains.

Abstract: The subject of the study is the cyclicality of the yedoma strata in the Mayn River valley of Southern Chukotka. The author explores the Late Pleistocene syngenetic strata containing syngenetic ice wedges in the Mayn River valley of Southern Chukotka: lacustrine and lacustrine-alluvial sediments in the Ledovy exposure outcrop, and lacustrine-alluvial sediments of the Ust’-Algan exposure. These strata are located close to each other, and formed with the diverse in lithological composition and facies sendiments: from coarse sand with pebble of river facies to silty facies, permeated with thick ice wedges of different configurations. The main research method is the field study of cryolithological structure of the natural exposures. The author also examines the radiocarbon age of the strata of the wedges, the oxygen-isotope and hydrochemical composition of ice wedges. The following conclusions were made:1. The hierarchy of the main types of cyclicity, observed in the studied syncryogenic strata is clarified;2. The duration of micro-, meso- and macro-cycles in formation of the yedoma strata of the Main River valley is determined- cyclite polygonal ice wedges in the section of lacustrine strata of the Ledovy exposure- heterocyclic polygonal ice wedges of in the section of lacustrine-alluvial yedoma of Ledovy exposure- heterocyclitic polygonal ice wedges in the  section of Ust’-Algan exposure.

Abstract: The object of this research is the yedomas in Alaska and Klondike with the well-defined cyclic qualities. The author examines the mesocyclic polygonal-lode complex McLeod Point, mesocyclic polygonal-lode complex  on the Itkillik River, mesocyclic polygonal-lode complex in Chatanika, mesocyclic polygonal-lode complex  in the Last Chance Creek valley, mesocyclic polygonal-lode complex in the Fox permafrost tunnel, mesocyclites in the Seward Peninsula, Colville River valley, the northern slope of Alaska, and Klondike near Dawson City. The main research method contains the analysis of cryolithological structure, radiocarbon dating, oxygen-isotope and hydrogen-isotope data. The main result of the conducted research lies in identification of mesocyclites in the Alaska and Klondike yedomas, such as: a) there are three vertical growth mesocyclitic stages in the MacLeod Point yedoma; b) four vertical growth mesocyclitic stages are common in the Chatanika yedoma; c) at least four vertical growth mesocyclitic stages are identified in the Itkillik yedoma; d) at least four vertical growth mesocyclitic stages are revealed in the Fox permafrost yedoma; e) at least four vertical growth mesocyclitic stages are tiers are distinguished in the Last Chance Creek valley; f) large, two or more layered syngenetic lodes are detected in the Seward Peninsula, Colville River valley , and the northern slope of Alaska yedomas – two-layered lodes; g) Klondike yedoma, near the Dawson City, is characterized with powerful two-three layered syngenetic lodes.

Abstract: In this article the influence of drying temperature and dispersion of sandy soils on isotopic composition of water evaporated from soils is investigated. These studies are relevant for those permafrost areas, where sharply continental conditions with very warm summers and active evaporation. During evaporation water molecules with the lightest isotopes evaporate first, after then the molecules with more heavy isotopes evaporate. At high drying temperatures (180, 200, 220 °C) the isotopic composition of moisture categories in soils becomes heavier in the series: free water< transitional water < bound water. The effect of soil grain size on the isotopic composition of water evaporated from sands is more noticeable at lower temperatures, wherein the water vaporized from silty sand at the same temperature is isotopically heavier than water evaporated from medium-grained sand. For medium-grained sand portions of the condensate evaporated at a higher temperature have a heavier isotopic composition in δ18O and δ2H values, the same relationship is observed for silty sand in deuterium values, but the effect of temperature is less pronounced for silty sand in oxygen values.

Abstract: The subject of this research is the cryolithological and isotope-geochemical peculiarities of massive ice wedges found in the Yedoma formation of Stanchikovsky Yar on the Maly Anyui River – the left affluent of the Kolyma River. The study was carried out in August 2018. The Yedoma with a height of 25-35 m was found over the span of 4 km downstream the river from Anyuysk village. The massive ice wedges are exposed in over 20 fragments of Yedoma at different heights – from 10 to 35 m. The following methods were applied in the course of the research: cryolithological study of the exposed ice wedges and analysis of the stable oxygen isotope variations in ice wedge. It study demonstrates that the polygonal ice complex of the Yedoma formation of Stanchikovsky Yar, in all likelihood, is represented by 3-4 layered ice wedges. The heads of ice wedges are embedded at the approximate altitudes of 35, 25, 15 and 10 m above the level of Maly Anyui River. The narrowly buried ice wedges of 0.5 m thickness also indicate the layerage of structure of the complex. The age of the explored by the authors ice wedges varies between 25 and 35 and 25-29 ka. In this period, based upon the persistently low values of oxygen-isotope composition of massive ice wedges, the climatic conditions were fairly severe; the average winter air temperatures comprised –31, –33°С, while the average January could reach –46, –47°С.

Abstract: The subject of this research is the Late Pleistocene and Holocene massive ice wedges discovered in the exposures of Yedoma formation nearby Chersky settlement and a small Holocene exposure on the lakeshore explored close to the scientific station on the edge of Chersky. Relatively small fragments of the Late Pleistocene ice wedges, which are up to 1.5 m wide and up to 2 m high, were found in the Yedoma formation. The massive ice wedges in these two exposures were tested for clarification of paleoclimatic conditions of their development. The main research methods contain the field study of massive ice wedges and enclosing sediments, their testing and analysis of the oxygen isotope composition of the ice wedges. The measurement of oxygen isotope composition are conducted in the regime of the constant flow of helium (CF-IRMS) on the Delta-V mass spectrometer using the gas-bench complex. The scientific novelty lies in examination of the new previously undescribed exposure of the Late Pleistocene ice wedges in Chersky settlement, as well as a small Holocene wedge on the edge of the settlement. The value of δ18О in the Late Pleistocene ice wedges vary from –32.24 to –31.45‰, while in the Holocene ice wedge from –27.94 to –26.37‰.

Abstract: The study of the combinations of various types of ground and surface ice as paragenetic complexes are of particular interest, in order to understand the conditions of the ice formation. The following ice ensembles are examined: a) paragenetic combinations of ice wedge, ice with segregated and injection (intrusive) segregated ice in palsa and pingo cores, b) paragenetic combinations of ice wedge with massive ice, c) paragenetic combinations of ice wedge with ground icing (aufeis) and d) paragenetic combinations of ice wedge with glaciers and even icebergs ice. Among the main conclusions of the conducted research are the following claims: 1) Ice wedges form paragenetic combination with many types of underground and aboveground ice; 2) paragenesis of the wedges with anchor ice can be found in both, palsas and pingos.

Abstract: Frozen mounds are the object of the study, the formation of which is associated with segregation of ice and moisture migration to the freezing front. Two varieties are considered as follows: typical palsa in the peat bogs, and lithalsa – ice-mineral (and sometimes mineral-ice) mounds in mineral dispersed sediments. A review of the isotopic composition of seasonal and perennial frozen mounds is presented. Three main sources of water for lithalsa and palsa are distinguished. The main research method is the analysis of oxygen and hydrogen isotopic composition of the ice cores of the lithalsa and palsa. The new results of the study are as follows: a) the isotope composition of the segregated ice of the palsa and lithalsa cores is usually quite homogeneous: variations in oxygen rarely exceed 2-3‰; b) there is a definite correspondence between the isotopic composition of the ice of the palsa and lithalsa and the isotopic composition of the water of surrounding bog is lighter by 2-3‰; this is a result of fractionation during the freezing of the bog waters; c) comparison of the isotopic composition in the segregated ice of the palsa and lithalsa, atmospheric, surface and boggy waters revealed a close isotope-oxygen and isotope-hydrogen composition of them.

Abstract: The objects of this research is the massive ice beddings in the valley Mordyakha River valley, as well as the terrace of Seyakha River (Mutnaya) in the central part of Yamal Peninsula. First of the studied ice bedding outcrops is located the center of Yamal Peninsula, in the upper reaches of Mordyakha (68°11ʹ18ʺN, 68°51ʹ39ʺE), at absolute elevation of 66-70 m; the second one (70°23.4 N, 68°19.4 E) is located 0.6 km towards southwest of the field base GP-1 Bovanenkovo deposit and 5 km towards northwest of Bovanenkovo settlement, at absolute elevation of 87 m. The authors meticulously examine the structure of bedded deposits and peculiarities of their contacts with the enclosing rocks. The article studies the concentration of stable isotopes of oxygen and hydrogen in ice, composition of the main anions and cations, as well spore-pollen remains within ice. The following conclusions were made: a) the studied bedded deposits are classifies as intra-ground type; b) one of the main water source that formed massive ice were lake waters and talik water ; c) in the process of ice formation took place a significant isotope fractionation, which led to the formation of layers with isotope composition heavier than the original lake waters.

Abstract: The object of the study is the isotopic composition of the January snow on the slopes of the Aibga and Psekhako mountains in Krasnaya Polyana in 2010 (29 snow samples) and 2017 (58 snow samples). In 2010, the snow cover was sampled on the Aibga ridges and the Psekhako Ridge. In 2017, on the slope of the Aibga ridge, fresh snow was sampled. Along the ski run Rosa Khutor, surface snow was also sampled. Isotopic composition measurements were performed using the Delta-V (Finnigan) mass spectrometer in the isotope-geochemical laboratory of the Faculty of Geography of Lomonosov Moscow State University. The authors of the study conclude that high values of the deuterium excess can be caused by three reasons: 1) the air mass itself, which had been above the inland areas for a long time, has changed its isotope characteristics due to re-evaporation and moisture condensation, 2) the conditions of condensation, when adiabatic cooling of the air mass leads to isotope depletion in the precipitation, more prominent for δ18O than for δ2H and 3) post-sedimentation processes on the snow surface. Perhaps the isotopic composition of the snow cover in Krasnaya Polyana is formed under the influence of all these three factors.

Abstract: The subject of the study is the yedoma, which is found in the Batagaika crater (67°34'49 "N, 134°46'19" E), located 10 km southeast of Batagay settlement, Verkhoyansk settlement, the Sakha (Yakutia) Republic. The crater is located about 1.5 km downslope of the Kirgillyakh mountain; its absolute height is about 325 m. The main research methods are: fieldwork, analysis of oxygen and hydrogen stable isotopic composition, analysis of ion composition and content of dissolved forms of trace elements and their distribution in ice-wedges of the yedoma. Oxygen and hydrogen stable isotopic composition, ion composition and the content of the dissolved forms of minor and major elements were studied for the first time in ice-wedges of the Batagaika crater. It has been revealed that the ice-wedges of the Batagaika crater are of hydrocarbonate-calcium composition, a uniform content of minor and major elements is observed within each ice-wedge. The isotopic composition of the ice-wedges located in the upper (the average values of δ18O is –34.4‰, the value of δ2H is –266 ‰) and lower (the average value of δ18O is –35.7 ‰, the value of δ2H is –276‰) parts of the Batagaika crater indicates that the average January air palaeotemperature was from –51 to –55 °C.

Abstract: The object of the study is the palsa located near Abez' settlement, in the Komi Republic, the northeast of European Russia. The authors re-examined the palsa in 2001, 2016 and 2017. The main research methods were: scrutinous fixation of the palsa morphology and its comparison with the photographs of different years; radiocarbon dating of peat; study of stable carbon isotopes in peat profiles. In 15 years' time, almost complete degradation of the palsa is observed. The height of the palsa has reduced by more than 2 m. Now their height does not exceed 1.5 m. During the period of 1960-2015, the average annual air temperature at nearby meteorological stations had been increasing by 2° C averagely. The most probable reason for the rapid degradation of the palsa in the area of Abez' settlement is a combination of a positive climatic trend and significant draining of the lake-marsh basin as a result of the construction of the Bovanenkovo-Ukhta gas pipeline, which crosses the southern part of the palsa. It is shown that the palsa in the southern regions - in the area of the Bugry Polyarnye and Nikita stations - have no signs of degradation.

Abstract: The author shows that the purpose of cyclocryostratigraphy is to determine, characterize and interpret periodic or quasiperiodic variations in the cryostratigraphy of permafrost sections (mainly syncriogenic ones) and their use for refining the features of the formation of permafrost. The author formulates the concept of cryocyclitis as a complex of permafrost layers and their associations with ice wedges, characterized by the direction and continuity of the change in the cryostructures properties of the ground ice and its surrounding sediments, reflected in the location of the boundaries between them, which can be seen in a vertical section (in a borehole, outcrop, bore pit, etc.). The main research methods are the radiocarbon, stable isotope and geochemical ones. The study shows that often in the yedoma strata individual cyclites duplicate each other, thus demonstrating a continuous process. The author performs the cyclocryostratigraphic research of the structural features and development of the Late Pleistocene syngenetic ice wedge in the cyclical yedoma of the Asian Arctic: Western Siberia, Yakutia, Chukotka, Novosibirsk Islands, Alaska and northern Canada.Three cycles can be distinguished in the development of syngenetic ice wedges. Microcycles result from the changes in active-layer depth and the accumulation of a thin sedimentlayer over several years. Their vertical scale varies from centimetres to tens of centimetres, and their formation time ranges from one to hundreds of years. Mesocycles result from a change in the lake water level if ice-wedge formation took place on the banks or beneath shallow water. The vertical scale of mesocycles is a few metres, and their timescale usually varies from several hundred to a few thousand years. Macrocycles relate to a major change in the sedimentationregime or rarely – and mostly at the southern border of ice-wedge formation – with major climatic oscillations. The vertical scale of macrocycles numbers tens of metres, and their duration varies usually from many tens to sometimes hundreds of thousands of years.

Abstract: The subject of the study is the Late Pleistocene and Holocene syngenetic ice wedges of the Mamontova Gora and Syrdakh outcrops and the reconstruction of winter temperatures of ice wedge formation periods. The main study objects are ice wedges over 7 m high in the upper part of the 50-60-meter heigh terrace of the Mamontova Gora, the ice wedges are surrounded by the 9-12 m thick lacustrine loamy sediments. The Holocene and modern ice wedges on the high flood plain of the Aldan River are also studied. In the thermoerosine ravine near Lake Syrdakh the Late Pleistocene ice wedges were also studied. The main research methods are the mass-spectrometry analysis of the oxygen and hydrogen isotope composition of the Late Pleistocene, Holocene and modern ice wedges. Also a direct dating of microinnclusions of organics material from ice wedges by the AMS method in the Mamontova Gora was performed. New radiocarbon dates of organic matter from sediments surrounding and overlying of ice wedges has been obtained. Using the known ratios of mean winter and mean January temperatures with isotopic composition of ice wedges, the winter palaeotemperatures of Central Yakutia were reconstructed for key periods of the Late Pleistocene. The main conclusions of the study are: a) the mean winter air temperature during the majority of the period of formation of the Late Pleistocene ice wedges of the Mamontova Gora was in the range from -28 to -31 °C, the average January temperatures reached -42, -46 °C; b) in the Syrdach Lake region the winter conditions were slightly more severe: the mean winter temperature varied mainly from -30 to -32 ° C, the average January temperatures reached -44, -48 °C; c) in the Holocene, the average winter temperatures were higher: from -24 to -28 °C, and the mean January temperatures from -36 to -42 °C.

Abstract: The author formulates a new line of research of permafrost and, in particular, homogeneous yedoma, - cyclocryostratigraphy. Cyclo-cryostratigraphy studies the rotation of different vertical frozen soil units of permafrost sediments in yedoma sections. The study demonstrates the cyclicity in the flysch formations in pre-Quaternary and Quaternary sediments on the Black Sea coast, near the Novomikhailovskoye settlement., in the Berriasian-Valanginian exposure near the village of Konakhkend, Azerbaijan, in the Eocene sediments of the Navagir range, the northwestern spurs of the Caucasus, the Abrau peninsula, in interstratifying sands and sandy loams in the Nagym section in the mouth of the Olenyok channel. The cyclicity in the vertical arrangement of pseudomorphs and subterranean veins outside the permafrost zone has been investigated. The main research methods are lithological, cryostratigraphical, radiocarbon, isotope, geochemical. The author detects cyclicity during the field research, and verifies its parameters with analytical determinations. The main results of the study include the successive transition from flysch cycles to the cyclicity of clays and cyclostratigraphic features of paleo-sections with pseudomorphs and ground vein. The author analyzes mesocyclic bedding of ground veins and pseudomorphs in the sections of Western Europe: Aschersleben in Germany, Kesselt, Remicourt and Harmignies in Belgium. The author analyzes stratification of pseudomorphs in the Late Pleistocene stratum in the Grove section in the north of the Netherlands. In the north of Italy, in the valley of the Po river, a multi-tier complex of pseudomorphs in loess strata is considered. A scheme for stratification of pseudomorphs in the Kotkino area on the left bank of the Soyma River, the tributary of the Pechora River, is considered.

Abstract: The subject of the study is the content of trace elements (heavy metals and metalloids) in the Late Pleistocene ice-wedge casts of three yedoma blocks of Northern Yakutia: Kular, Bison and Duvanny Yar. Yedoma deposits of Duvanny Yar are exposed on the right bank in the lower course of the Kolyma River, near the Duvanny riffle, in the Kolyma Lowland. It is drained by the northward flowing Kolyma River, the sixth largest river flowing into the Arctic Ocean. The lowland is bordered by the North Anyuy Range to the east, the Yukagir Plateau to the south, the Alazeya Plateau to the southwest and the Ulakhan-Sis Ridge to the northwest. The Late Pleistocene Bison yedoma complex is located on the right bank of the Kolyma River, in the mouth of the Lakeevskaya Channel 15 km below the Duvanny riffle. Yedoma near the Kular village in the foothills of the Kular range is located on the mild slope of southern aspect in the valley of the Burguaat creek in the form of an inclined slope extending over a slope of more than 1 km. The main reseacrh method is atomic absorption spectroscopy, performed in the V.V. Dokuchaev Soil Science Institute. Samples of ice wedges were sampled in the field in polyethylene bags, melted at a temperature not higher than 15 °C and poured into chemically inert plastic bottles. The main conclusions of the study are as follows: a) in the late Pleistocene ice-wedge casts of the Bison and Duvanny Yar sections, lithophile elements (Mn, Sr) are significantly distinguished in comparison with the Kular section; b) the content of Sr in the ice of the Bison section is below the world’s average for surface water; c) Mn and Fe, highly mobile in gley reducting medium, are represented in the ice of the Duvanny Yar and Bison sections in much larger quantities than in the Kular section; it can be connected with different redox conditions during the formation of ice wedges. Probably in Kular the conditions were oxidative (for a long time) or more alkaline than in other sections, and in Duvanny Yar and Bison – mostly gley reducing and acid.

Abstract: The paper studies the composition of water-soluble salts of ice wedges and massive ice of different regions of the Russian Arctic: Western Siberia, central and northern Yakutia, Chukotka. The research methodology is based on the fact, that the chemical composition of ground ice reflects the hydrochemical conditions of the period of ice formation or freezing and can serve as an important criterion for the reconstruction of a paleo-facial component in paleo-geocryological elaborations. To compare the ice of different regions, the author develops a hydro-chemical classification (systematization) of ground ice: ultra-fresh ice with mineralization less than 50 mg / l, fresh ice - 50-200 mg / l, desalted - 200-400 mg / l, light-salted - 400-1000 mg / l, mesohaline - 1000-5000 mg / l, highly saline - 5000 mg / l and more. The author finds out that ice mineralization is less than 0.05 g / l in more than a half of samples from the ice wedges in Chukotka, while the ice samples with the same mineralization reach only 16% of cases in Western Siberia and 14% of cases in Northern Yakutia. However, if we take a broader range – (mineralization less than 0.15 g / l), then the closest resemblance is observed. This range includes almost 100% of the analyzed samples in Chukotka, 89% in Western Siberia and 80% in Northern Yakutia. These findings suggest that though there are regional differences between the composition of salts in permafrost sediments of different Arctic regions of Eurasia (caused primarily by the uneven nature of air masses transport in wintertime and the different influence of seas and oceans), their similarity is much more significant. This manifests itself in low mineralization and dominance of hydrocarbons, indicating, most likely, the atmospheric nature of water that had fed ice wedges in the Late Pleistocene, in the Holocene and the present time. Certain findings of high-salt ice wedges in rare cases indicate the possibility of sea, lagoon and bog waters participation in the ice wedges formation in the Late Pleistocene and Holocene in the shallow water conditions. In the coastal areas high mineralization indicates the involvement of dead and salt-affected waters of seasonally thawed layer. Data on the hydrochemical composition of massive ice are often decisive for determining the genesis of ice layer. It had resulted in increase of salinity downward the massive ice section Ledyanaya Gora (Ice Mountain) in the Yenisei River valley, indicating the intra-ground origin of the ice. The lower horizons of massive ice in the New Siberian Archipelago formed syngenetically by the injection. Strongly mineralized (4700 mg / l) massive ice formed at epigenetic freezing process found in wells at great depths in the northern Urals and Pai-Khoi.

Abstract: The palaeoreconstructions of the mean January temperatures based on the distribution of δ values (oxygen isotope composition) in the Late Pleistocene ice wedges in yedoma dated by radiocarbon are yielded. Verification of the equation linking current data of δ values in modern ice wedges with mean January temperatures has been done. In yedoma of different regions of the Russian Arctic formed 30-12 ka BP made the analysis reliability of radiocarbon ages. It is enabled to set on the time scale the isotopic events with high temporal resolution - with step 2-4 ka. New maps of the mean January palaeotemperatures for the time intervals 30-28, 24-22, 20-18, 16-12 ka BP are created for the Russian Arctic.