Review: The subject of this research is the diverse forms of space and time reflection in the development of geosystems (GS). The object of this research is the GS related to space and existing only in time. The author carefully examines such aspects of the topic as space and time, inseparable from each other, and if compared to other characteristics, are the paramount attributes of geosystems (natural, technogenic, and social) in the typical and anomalous environments. Particular attention is given to consideration of "time", characterized by the active (physical) properties influencing the events in geographic space and manifesting in opposition to the normal flow of processes, leading to the destruction of GS. The main conclusions lie in the positions determining the exogenous crisis situations and disasters as predicted. Author’s special contribution is the revealed opportunity to make certain adjustments to the practice of natural resource management considering sustainable development of the territory. The scientific novelty consists in tracing the sustainable development of the territory, which is based on taking into account not only typical, but also anomalous natural processes and phenomena. Because the exogenous crisis situations and disaster are predicted, the practice of natural resource management can be adjusted considering sustainable development of the territory.

Keywords: Far East, natural risks, geographical cover, geosystems, development, time, space, Sustainable development of the territory, disasters, exogenous crisis situations

Review: The goal of this research lies in examination of the possibility of application of the structurally paragenetic method as a methodological direction in studying permafrost formations; as well as in formulation of the theoretical principles for studying cryogenic formations on the basis of paragenetic approach. For achieving the set objective, the author substantiated the provisions on the necessity of using paragenetic constructs in geocryology; justifies the insufficiency of genetic approach in analyzing the emergence of cryogenic formations; considers the possibility of using the structural paragenetic analysis to restore the geodynamic conditions of emergence of the various cryogenic formations; presents classification of different parageneses of the various cryogenic formations occurrent in the cryolithozone. As a result of this research, the author was able to demonstrate the need for shifting from the genetic method of studying of permafrost formation towards the structural-paragenetic method. The main conclusion lies in the statement that cryogenic geosystems of any rank represent the patterned paragenetic complexes that reflect both, the ongoing processes in emergence of permafrost formation, as well as in the already formed frozen arrays. The article examines the already existing genetic classification of the genetic types of subsurface ice sheets; substantiates the application of paragenetic approach in studying the subsurface ice sheets; develops the basic framework of structura-paragenetic method that views permafrost formations as the hierarchically arranged cryogenic geosystems, consisting of the paragenetically connected associations and structural elements.

Keywords: plastic deformations, syngenetic, epigenetic, injection ice, segregated ice, massive ground ice, paragenetic relationships, paragenesis, fluid geodynamics, permafrost

Review: This article presents the results of model experiments on the ability of microorganism cells to migrate in pore space of the various dispersion frozen soils: Neogene sand of the Mammoth Mountain (Central Yakutia), quartz sand and kaolin clay at a fixed nedagive temperature (-6.5°C). Currently, there are known the basic parameters of microbial transport in the soils; however, the existing data on possibility of their migration in frozen soils and rocks is either contradictory or absent. The study was carried out on the example cells of Bacillus cereus strain F. The experiments were conducted in deep-freeze at a fixed negative temperature throughout one year. The question on the possibility of microorganism cells migration in permafrost is relevant from the perspective of the paramount global life preservation issues, stratigraphy of the various permafrost arrays, as well as their dynamics in the conditions of climate warming and emergence of risks of bringing microflora with the unknown properties to the modern ecosystems. Throughout the observation period, there was detected no evidence of migration of the model bacterial cells in frozen soils. The author established that the pattern of change in the number of colony-forming cells of the model organism in inoculated part of the samples of frozen soils is greatly affected by the level of their dispersion and aggregation.

Keywords: unfrozen water, particle size, sand, clay, microorganisms, permafrost, frozen soil, metabolic activity, colony-forming unit, migration

Review: The object of this research is the syncryogenic sands developed in the territory of Russian cryolithozone. The syncryogenic sands are deposited in the upper part of the geological section and serve as foundation for multiple engineering structures; this is why their engineering-geological characteristics attains an important. The article discusses the peculiarities of the composition, structure and qualities of syncriogenic sands within the boundaries of different regions of the country: European North, Western and Eastern Siberia, Yano-Kolyma lowland and mountain-folded structures of Siberia and the Far East. It is noted that among the soils under consideration, there is a variety of granulometric differences – from gravelly to silty. The cryogenic structure is mainly massive; in silty and peaty sand soils, as well as in due to the presence of clay interlayers, it is typically laminated. Syncryogenic sands tend to have higher ice content than epicryogenic sands, and are characterized by a relatively uniform or unifromly-cyclic distribution of the volume ice content in depth. The higher is the sand dispersion, the higher is their natural moisture content and porosity, and the lower is the density of soil and soil skeleton. The fine and silty lithologies with laminated cryotexture demonstrate significantly subsidence during thawing and frequently transform into running sand. In the coastal areas, the syncryogenic sands are typically salinized. The higher is their salinity, the higher is the compressibility.

Keywords: cryogenic structure, ice content, properties, structure, composition, soils, syncryogenict sands, platforms, orogens, Russia

Review: The object of this research is the exploration of anomalous sections of permafrost retreat at the soil baseline. In such cases, the apex of soil frost attains a complicated shape, forming the steep edges and mirrors of subpermafrost water. The authors propose a new  method of seismic survey  (0.5-1.0 kHz). The suggested seismic method modification is based on the joint application of the refracted and reflected waves in accordance with time curves of first onsets in their complicated shape, considering the below-cutoff angles of retraction within the depression. The time curves of the retracted waves were solved using the complex numbers; while their geometry remained traditional – the null time method  for determining the depth of refracting boundary and differential time curves for calculating velocities in the apex of depression. The modified seismic survey for studying the anomalous sections of permafrost retreat under the earth structures in cold regions was obtained and tested in the course of the research. It allows mapping out the local depressions with steep edges under embankments, occurred due to violation of the production sequence of transportation systems or normal exploitation of the structures built in such conditions. The surface seismic surveying using the method of retracted waves, and particularly, conducted via the null and differential time curve have a potential for modification depending of the current objectives. In the conditions of below-cutoff angles of waves retraction, the tasks on determining the subsurface depressions are solved mathematically, with application of complex numbers; at the same time, the basic conditions for the method of retracted waves, such as coordination of time curves in mutual duration and the precision of determination of the average velocities remain unchanged.  

Keywords: time-travel graph, refracted waves, local discontinuities, degradation, top of permafrost, permafrost, subgrade, seismoacoustic studies, elastic waves, refracting boundary

Review: The ice phenomena on the Arctic rivers often cause hazardous hydrological conditions and processes: ice-clogging floods and ice dams; damage of hydraulic structures and the fleet during the spring ice run. In winter, the rivers are used for navigation and construction of ice crossings. The article demonstrates the key stages in studying the ice regime of Arctic Zone rivers in the XX century. The author examines the peculiarities of establishment of the monitoring system and methods of ice forecasts in the conditions of limited network of hydrological posts. The research presents the main approaches for assessing the possible changes in the characteristics of river ice regime, flowing in the severe climatic conditions, with variable anthropogenic impact and different scenarios of climate change. The most promising directions of the modern river ice research of in Russia and foreign countries are highlighted: the use of satellite imagery data; the development of new approaches in ice forecasts; assessment of the response of ice regime to the climate change. It is demonstrated that the advancement of these directions is possible on the basis of national and global experience.

Keywords: river-ice forecasts, river-ice monitoring, dangerous ice phenomena, Arctic rivers, the history of Arctic exploration, climate change, the Arctic, river ice, satellite imagery, future changes in river ice