Abstract: The subject of the study is a new formal subdivision of Holocene epoch applied to the northern regions of the Russian permafrost. The following criteria are considered: criteria for the modern allocation of three calendar periods of the Holocene; comparison with the Blitt-Sernander scheme; comparison with the three-term division of the Holocene for the Russian Arctic, proposed by Yu.K.Vasilchuk. In 2008, the International Commission on Stratigraphy (IUGS) established the boundary between the Holocene and the Neo-Pleistocene at the turn of about 11,700 calibrated years ago (cal. l. n.). In 2018, in addition to the well-known Blitt-Sernander division, the Holocene was divided by IUGS into three tiers: Greenland (from 11,700 to 8,200 cal. years ago), North Grippian (from 8200 to 4200 cal. years ago) and Meghalayan (beginning 4200 cal. years ago). The features of the development of polygonal vein arrays during three Holocene periods were established and the average January air temperatures for four key regions of the Russian cryolithozone were reconstructed - the north of the European part of Russia, the north of Western Siberia, the lower reaches of the Kolyma River and the east of Chukotka. It is shown that, taking into account the new division of the Holocene, the Greenland and North Grippian periods of the Holocene (between 11.7 and 4.2 thousand years ago) are the stage of the most active development of peat bogs and the simultaneous formation of re–vein ice in them. The Meghalayan Holocene period was characterized by a marked decrease in the development of peatlands, but syngenetic growth of re-vein ice continued within the emerging floodplains and laids, especially within the torn-off areas.
The reconstructed average January air temperatures for four key regions of the Russian cryolithozone showed that the Greenland and North Grippian periods of the Holocene were characterized by slightly higher values (on average 1-2 °C higher) than the Meghalayan, with the exception of eastern Chukotka, for which an increase in the average January air temperature during the Meghalayan period was noted.

Abstract: The subject of this research is the ratio of isotopic parameters of deuterium of heavy oxygen in ice wedges. The authors considered such parameter as inclination of the line of the ration of deuterium of heavy oxygen in ice wedges. Proximal to GMLV (or LLMV) position of isotope values for ice wedge and inclination of the line proximate to 8 suggests that the ice wedge was formed from atmospheric precipitation (winter snow). The article provides separate examples of anomalous deuterium ratios of heavy oxygen with very low ration of line inclination, which in combination with the abnormally low dexc values indicate the indicate isotopic fractionation processes in snow before melting and/or melting snow water before filling frost-cutting cracks. Three author determines the three main types of ratios of deuterium m of heavy oxygen content in ice wedge: a) normal ratio δ2H-δ18O (with line inclination of the ratio proximate to GLMV or LLMW). b) ratio of deuterium  of heavy oxygen to deviation from GLMV or LLMW (with signs of change in the primary isotope signal of atmospheric precipitation), c) anomalous ratio of deuterium of heavy oxygen. It is shown that the first two types  are characteristic to most ice wedge under study in the vast part of the Russian cryolithozone from the European North to the east of Chukotka; the third type is obtained for several Holocene ice wedge in Transbaikal and upper Yenisei River. This may be explained by significant isotope transformation of snow cover in the conditions of distinctly continental climate.

Abstract: The subject of this research is the Late Pleistocene and Holocene ice wedges exposed near Chersky settlement, lower Kolyma River, and in the yedoma strata of the Stanchikovsky Yar on the Maly Anyuy River. In the yedoma of the Stanchikovsky Yar, multi-tiered syngenetic ice wedges were exposed at different levels – from 10 to 35 m above river level. Ice wedge in the lower tier was sampled in detail. In the yedoma strata near Chersky relatively small fragments of ice wedges up to 1.5 m wide and up to 2 m high were exposed. 1.5-2 km from Chersky within the lacusrtine-paludal depression Holocene ice wedges were exposed. Ice wedges in these three sections was sampled to clarify the geochemical conditions of their formation. It is shown that concentration of Na+, K+, Mg2+, Cl- and SO42- in Holocene and Late Pleistocene ice wedges is very low and mean values do not exceed 5 mg/L. The highest values were obtained for Ca2+, which corresponds to the predominance of this ion in the modern snow of Yakutia and indicates that ice wedges were formed mainly from melted snow. Rather high values of NO3-, reaching 14-27 mg/L, are quite likely due to the swampy environment within polygonal landscapes, where organic matter of both plant and animal origin is decomposed. For comparison, in the water of the Kolyma and Maly Anyu rivers, concentration of nitrates is quite low and does not exceed 0.3 mg/L.

Abstract: The research is conducted on the Holocene ice wedges exposed in the outcrop of the first marine terrace near the town of Anadyr, on the east of the Chukchi Peninsula, on the coast of Onemen Bay. Polygonal Relief is clearly traced on the surface of the first sea terrace in the area of explorations, the size of the polygons is about 8x12 m. In the exposed terrace, turf with a capacity of about 1.5 m is striped, underlied with sand clay with  capacity up to 2 m; below is the horizontally-stratified and. Ice wedges are embedded the turf (head of wedges) and in the underlying clay sand. The ice of wedges is vertically stratifies, yellowish gray. Ice wedges are also striped in turf  outcrops with capacity of up to 2.5 m, embedded in form of a lens from the terrace surface. Ice from three most fully exposed ice wedges was sampled for hydrochemical analysis. A total of 20 ice samples were collected from Holocene ice wedges, as well as ice from modern ice veinlet and water from Onemen Bay. It was found that mineralization of the studied Holocene ice wedges is low, does not exceed 80 mg/L, Na+, Ca2+, and Cl- dominate. Similar values of mineralization and ionic composition were obtained for modern ice veinlet. The obtained data correspond with data on ice wedges studied in other regions of Chukotka, both continental and coastal. Mineralization of most of the previously studied ice wedges did not exceed 150 mg/L. Low values of mineralization of ice wedges near Anadyr demonstrate mainly meteoric source of water forming ice, i.e. winter precipitation, prevalence of sodium and chlorine indicates the capture of sea aerosols by precipitation or wind introduction of droplets from the water area of the Onemen Bay to the surface of the snow cover.

Abstract: The subject of this research is the variation of deuterium isotopes and values of deuterium excess in recent growing ice wedges, with age of about 100 years, penetrating into growing ice wedges on the territory of the Russian permafrost. Variations of oxygen isotopes in recent growing ice wedges were previously studied in more detail. The joint determination of the isotope-oxygen and isotope-hydrogen composition will allow considering the additional cryogenic fractionation during ice vein growth in frost cracks. The main approach to the study is field sampling of recent ice veins that usually occur under interpolygonal wedge. The authors obtained new results of isotope data for recent growing ice wedges on the coast of the Chukotka Peninsula and summarized data from publications of the last 15-20 years. The main conclusion of the study is the confirmation of the predominantly atmospheric origin of moisture filling frost cracks. Another important conclusion is the fact that limited cryogenic fractionation usually accompanies the freezing of melted snow after it fills the frost crack.

Abstract: The subject of this study is the change in oxygen isotopic values in rudiments of the modern ice wedges in the lower reaches of Kolyma River. The authors provide delta18O values from the Ambarchik creek and Pokhodsk in the north to mouth of the Omolon River and Kolymsky rural locality in south of the  region. The critical analysis on publications dedicated to Nizhnekolymsky District and the adjacent territories, which were compared by the oxygen isotopic data and winter air temperatures. Similar works on Alaska and Northern Canada are also analyzed. The key research method is field testing of the rudiments of modern ice wedges, as well as the analysis of publications containing the data of delta18O values in Nizhnekolymsky District. The main conclusions of conducted research consist in the confirmation of dependences, obtained approximately 30 years ago by Y. K. Vasilchuk on Siberia overall and Nizhnekolymsky District in particular, connecting the delta18O values in the rusiments of modern ice wedges with average January air temperatures. The authors trace the tends of variability of the delta18O values from north to south according to distance from the moisture source and increase the degree of continentality.

Abstract: The object of this research is the massive ice-wedges and the enclosing Holocene sediments of the alluvial plain and a laida in the northwest of Gydan Peninsula in llower reaches of the Mongatalyangjyakha River. The authors analyze the distribution of chemical composition of sediments in depth, comparing with the structure of sediments. In examining the chemical composition of ice, particular attention is given to the determination of differentiation of mineralization and ionic composition within the range of a single wedge. For conducting the analysis of chemical composition, the authors picked out the pure ice from pits and exposures; the samples were additionally cleaned from the excessive mineral impurities. Some of the samples were filtered immediately after thawing. The parallel chemical analysis of water with sediment and filtered water demonstrated very similar results. The scientific novelty lies in determination of differentiation of ice wedged into the zones of uneven mineralization, which form as a result of shift in facial and hydrochemical situation during the growth of ice wedges. The main conclusions consists in the establishment of influence of the lagoon-marine water of Gydan Bay in lower reaches of Mongatalyangjyakha River, which manifested in the prevailing chlorine-sodium salinity of sediments, as well as in the development of differentiated by mineralization massive ice wedges, which were formed as the fresh thawed snow waters and river waters (on the alluvial plain) and the lagoon-marine water (on the laida).

Abstract: The object of this study is the ice wedges of Holocene age on the western coast of the Baydarata Bay, at the mouth of the Ngarka-Tambyakha River. In the coastal cliff structure of the thin polygonal peatland have been studied. The peatland is located in the upper part of the terrace 8-17 m high. The peat is underlain by gray icy loam with layered-lenticular cryogenic structure. Ice wedges revealed at the depth 0.8 m. Their width was 1.5-2 m, and outcropped height about 1.15 m high. One representative ice wedge was sampled across horizontal axis in the upper part, 9 samples were analyzed on a mass spectrometer, the oxygen isotope and hydrogen isotope composition of ice wedges was obtained. The main conclusions are: harsh winter air temperature in the area in Holocene varied between –16 and –19° С, which is about 10°С warmer compared to Late Pleistocene and were close to modern ones. Obtained results complement sparse information on Holocene winter air temperature for the Baydarata Bay coast.

Abstract: This article considers the migration frost mounds (palsa) in the settlement of Yeletsky in the northeast of Bolshezemelskaya tundra. The new radiocarbon dating on the frost mounds of various size and different stages of development within the boundaries of massif explored by the authors in 2000 and 2015. The work meticulously examines the representative 3m high frost mound with no signs of destruction, covered with peat having capacity over 1m. The object of the research is defined by the goal to characterize the conditions of peat accumulation and identify the moisture sources that form the upper part of the ice core. For the radiocarbon dating was selected the thawed peat on the top or shoulder of the mound. In the shafts was minutely (at intervals of 5-10cm) selected the peat for identifying the concentration of carbon and nitrogen and isotopic composition of carbon and nitrogen. From the bottom of the shaft using the electric ice auger MORA-ICE was drilled the wellbore in frozen peat and the underlying frozen loam, as well as selected the ice lenses. The determination of isotopic composition of oxygen and hydrogen of ice were conducted using the mass spectometer Delta-V; radiocarbon dating of the peat carried out in laboratory of archeological technology of the Institute of Material Culture of the Russian Academy of Sciences. The scientific novelty consists in the comprehensive approach towards exploring the peat deposit covering the frost mound.

Abstract: The research object is the isotopic composition of oxygen and hydrogen of ice-wedge casts, surface waters and atmospheric precipitation in Central Yakutia near the Mammoth Mountain, where the conditions are favourable in summer for evaporation and continental salinization of permafrost and subsurface ice. Special attention is given to the analysis of high indexes of isotopic composition of ice-wedge casts of the late Pleistocene, which can’t be explained by higher winter temperatures during the formation of ice wedges. The authors use hydrochemical data showing the signs of continental salinization in the fragments of wedges with heavy isotope composition. The main research method is the definition of isotopic composition of oxygen and hydrogen in the ice. In graphic form, one of the indicators of evaporation is the evaporation line, whose inclination on the dependency diagram δ18О – δ2Н is around 5. The authors show that continental salinization of the landscapes of Central Yakutia can be explained by the combination of the processes of perennial freezing of sediments and evaporation during summer seasons. The authors design the system of indexes of continental salinization of cryogenic lacustrine-boggy landscapes on the basis of isotopic and hydrochemical data of surface waters and subsurface ice: 1 – abnormal heavy isotopic composition; 2 – isotopic composition indexes are on the evaporation line, whose angle of inclination (usually lower than 5) is lower that the angle of inclination of the global meteoric water line (8); 3 – high salinity of ice-wedge casts and sediments with prevailing continental salts. The obtained results are accurate and can be easily reproduced by any isotope laboratory in the world. 

Abstract: The Chukchi Peninsula or Chukotka Peninsula at about 66° N 172° W, is the eastmost peninsula of Asia. Its eastern end is at Cape Dezhnev near the village of Uelen. It is bordered by the Chukchi Sea to the north, the Bering Sea to the south, and the Bering Strait to the east. Most of the Chukchi Peninsula is occupied by highlands up to 1000 m a.s.l height. Lowlands are found, as a rule, near large lagoons. The main features of the area (from Anadyr' town to Lavrentiya) are represented by a slightly hilly relief formed by fluvial erosion and marine abrasion of the Mesozoic blocks. For the determination of the ion composition of ice wedges, ice samples were taken both horizontally with an interval of 10-12 cm and vertically with an interval of 10-15 cm. The ion composition of the ice was analyzed by ion chromatography method in the geochemistry laboratory of the Department of Landscape Geochemistry and Soil Geography of the Faculty of Geography of Lomonosov Moscow State University on the ion chromatograph "Stayer". The detection limit for chloride ion was 0.02 mg / l. The hydrochemical composition of snow, rivers and lakes water, segregated ice and partly of ice wedges was carried out in the hydrochemical laboratory of PNIIIS by acid-base titration. Continuous permafrost occurs everywhere beneath the ground surface. Taliks (up to 30-40 m thick) often occur underneath the largest thermokarst lakes and in the and under the lower reaches of large rivers. The temperature of the permafrost averages -10 ° C in the axial parts of the mountain ridges and -4 ... -6 ° C in river valleys and on the coasts. The thickness of the permafrost varies from 500-700 m in the highest parts of the ridges to 200-300 m in the interior valleys.

Abstract: The research subject is the peat permafrost mounds on the northeast of Bolshezemelskaya tundra. The authors study the permafrost mounds at different stages of development – from the adolescent and growing to the mature and broken. The mature permafrost mounds are from 3 to 4,7 m high; some of them have the signs of primary breaking in the form of stains of bare peat or cavities on the surface. The height of adolescent permafrost mounds usually doesn’t exceed 1,5 – 2 m; the broken mounds look like peat mounds, surrounding the lows. The width of peat, superposing the mounds, varies from 0,8 to 1,2 m on mature mounds to 0,3-0,6 m on broken mounds. The authors sample the peat on mounds and lows (at 5-10 cm intervals); establish the radiocarbon age, the composition of carbon and nitrogen and the isotope composition of peat carbon. Radiocarbon dating shows that the studied mounds had formed in the period of Holocene optimum; the highest mounds formed about 7,7 – 4,8 thousand years ago. The authors show that within the limits of the studied mound landscapes in Holocene, the conditions of water intrusion, the composition of vegetative cover and the temperature of vegetation periods continually changed. Peat accumulated in the conditions of high water intrusion; the permafrost condition of peat had determined its low decaying and humification. Both in the period of Holocene optimum and at the present time, permafrost mounds develop cyclically, that is determined by both climate changes (air temperature and the snowiness of winters) and local factors, including the change of masses humidity.