Abstract: The subject of this research is the gas emission crater (Yamal crater), located in the southern part of Bovanenkovo deposit on the Yamal Peninsula. Generalization of data on the structure of crater soils components, natural conditions and laboratory results, allowed building a phenomenological model of the Yamal crater, with identification of different stages of its development. The cause for the emergence of the gas emission craters is the formation within the subsurface of permafrost rocks of the underground gas accumulation zones with the abnormally high pressure. The diverse geological and thermodynamic factors substantiate the various scenarios of their development. The main research method lies in consideration of the different structural elements of the Yamal crater as the phenomena that reflect the processes of its formation. In determination of the processes that form the gas emission craters, the authors apply the method of analogies. The conclusion is made that the gas emission craters eventuate the self-development of the fluid dynamics geosystems, which are the local ice-surface gas-saturated formations in non-equilibrium thermodynamic state in relation to the enclosing permafrost rocks. The development of the selected geosystems is defined by paragenetic links between gas filtration processes and deformations of gas-saturated ice-surface material (from viscoplastic motion to brittle fracture). The Yamal crater is a particular example of a full and complete life cycle of the development of selected geosystems: from the initial stage – the formation of conditions for decomposition of gas hydrates, to the final stage – the explosion and release of ice-surface material.

Keywords: ice ground saturated geosystems, fluid geodynamics, fluids, gas filtration, dissociation of gas hydrates, ice flow, plastic deformations, permafrost, stage of development,, paragenetic relationships

Abstract: The subject of this research is the current state of wind regime in the Arctic and variability in response to the global warming. The performed analysis concerns both, the average value of wind speed and the extremely high that exceed the specified threshold value in the present-day conditions and in the late XXI century. The authors examines the spatiotemporal variability of the value of wind speed of different frequency in the Arctic territory for the climate system models that participated in the World Climate Research Program CMIP5. Particular attention is given to the regional peculiarities of climate forecast of wind speed over the seas of the Russian Arctic. The results are obtained from the data of reanalysis ERA-Interim and climate system models of the CMIP5 project for the current (Historical experiment) and forecast (experiment RCP8.5) climate. The main result of this research became the quantitative estimates of climatic forecast of the average and extreme wind speed in the Arctic by 2100 in terms of implementation of RCP8.5 scenario, which implies the most rapid rise of temperature throughout the XXI century. It is acknowledged that with the ongoing warming over the major part of the Arctic, the growth trend of not only the average, but also the extreme values of wind speed is typical for most models of the CMIP5 project. The decrease is noted over the greater part of the north of Eurasia, Greenland, the North Atlantic, the Norwegian Sea, while the rest of the Arctic is experiencing an increase in average and extreme wind speeds. The drop in temperature is recorded over the most of Eurasia, Greenland, North Atlantic and Norwegian Sea, while over the rest of the Arctic shows the increase in average and extreme wind speeds.

Keywords: sea ice, oceanatmosphere interaction, extremes, climate modelling, Arctic, climate change, wind speed, greenhouse effect, global warming, climate risks

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.

Keywords: Kolyma River, Maly Anyui River, cyclicity, radiocarbon age, oxygen isotope, Late Pleistocene, ice wedges, yedoma, Yakutia, palaeotemperatures

Abstract: The object of this research is the epicryogenic sands developed in the territory Russia. They are located in all parts of the permafrost zone, but mostly concentrated within the ancient and young platforms. At the same time, within the zone of compact spreading of permafrost rocks, epicryogenic sands are often covered with syncryogenic sediments; and in the zone of joint spreading of thawed and frozen rocks are embedded in the surface. Sands of this type occur as part of glacial, aqueoglacial, glaciolacustrine, marine, alluvial-marine, glacial-marine, lacustrine-alluvial, alluvial and eolian genetic units of quaternary deposits. In certain districts, the epigenetic permafrost sands are identified as a part of the ancient pre-quaternary formations. In the Timan-Pechora platform it is the terrigene gray-colored formation of the Middle Jurassic-Lower Cretaceous; in the Western Siberia – the terrigene lignite-bearing Oligocene; in the Khatanga trough – the terrigene of Upper Cretaceous and Jurassic-Lower Cretaceous, as well as the coal-measure of the Upper Cretaceous. Within the limits of Vilyuy syneclise and Predverkhoyansk foredeep, the epicryogenic sands are confined to the molasse of Lower and Middle Jurassic, coal-bearing formations of Upper Jurassic–Lower Cretaceous, terrigene formations of Upper Cretaceous and Neogene. In the territories of folded mountain constructs, epicryogenic sandy soils are meagerly developed in hollows and river valleys as part of alluvial, lacustrine-alluvial, aqueoglacial and eolian quaternary complexes.

Keywords: genesis, age, orogens, platforms, Russia, extent, epicryogenic, sands, formations, pre-Quaternary

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).

Keywords: ice-wedge salinity, soil salinity, laida, floodplain, Holocene, polygonal network, north of Gydan Peninsula, ice-wedge, ion composition, sedimentation regime

Abstract: The object of this research is the permafrost sandy soils of Eastern Siberia. Their age range spans from the Mesozoic through the Holocene. The pre-quaternary permafrost sands are developed within the limits Vilyuy syneclise and Khatanga trough, and fall into the epicryogenic category. The quaternary sands are composed of aqueoglacial, glaciolacustrine, marine alluvial-marine, eolian, lacustrine-alluvial and alluvial genetic units. In the northern districts, the syncryogenic soils usually compose the upper part of the cutoffs of these units, while underlying the epicryogenic soils. In central and southern districts, the epicryogenic sands are often embedded on the surface. The study of archive and published materials allowed revealing and generalizing the peculiarities of composition, structure and characteristics of permafrost sands of the platform and mountain territories of Eastern Siberia. It is noted that their granulometric composition extensively varies – from gravelly to silty types. The higher is the sand dispersion, the higher is their natural moisture and porosity factor, and the lower is the density of soil and soil skeleton. The fine and silty sandy soils often have a schlieren cryogenic structure, significantly settle during thawing and frequently develop into the running sands. The larger sands have a predominantly massive cryogenic structure, and settle insignificantly during thawing.

Keywords: platforms, cryogenic structure, properties, structure, composition, epicryogenic, syncryogenic, permafrost sands, orogens, Eastern Siberia

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‰.

Keywords: Yakutia, Kolyma River, stable oxygen isotope, Pleistocene, Holocene lacustrine sedimets, yedoma, permafrost, ice wedge, Siberia, palaeotmperature