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Concepts of the stratigraphy of the coastal and shallow-sea sections of the uppermost Middle Jurassic and Lower Cretaceous, exposed on the right bank of the Anabar River, have radically changed many times. The performed study and analysis of the published data are aimed at refining the bio- and lithostratigraphic subdivision of the section, substantiating its stratigraphic completeness, and describing the identified stratigraphic units in detail. Comprehensive biostratigraphic studies of the uppermost Bathonian-lowermost Boreal Berriasian reveal a sequence of nine biostratigraphic units with dinocysts and palynoflora in the ranks of zones and local zones. Some of the palynological biostratigraphic units have been identified for the first time. Foraminifer assemblages of the boreal standard zones are recorded in the sections under study. The obtained biostratigraphic data and analysis of all known ammonite occurrences make it possible to demonstrate the stratigraphic continuity of the section in the Anabar River region, despite the reduced thickness of the stratigraphic units. The stratigraphic position of the boundary between the Sodiemykha and Buolkalakh formations is accurately defined. According to the interpretation proposed, the basal horizon of the Buolkalakh Formation is associated with a beginning of a new major sedimentation stage in the late Oxfordian-early Kimmeridgian, identified as the lower boundary of lithostratigraphic units of different ranks throughout the entire Arctic Region and partially in the Boreal Region. The lithogeochemical parameters of the studied formations are obtained for the first time. The content of C_org in the studied samples does not exceed its Clarke values, and the pyrolytic parameter T _max indicates that the organic matter is immature and the petroleum potential is low. The considered organic matter of the rocks is characterized by a heavy isotope composition of carbon, suggesting its mostly terrigenous genesis.

For the first time in the scientific literature, an analysis is made of the channel formation conditions and of the morphology and channel regime of the Lower Ob (within Khanty-Mansi Autonomous Okrug - Yugra) which in this context, in spite of its important economic and water transport significance, remains largely unexplored. The geomorphological structure of the valley determines downstream of the confluence of the river with the Irtysh the concentration of the river at the right valley side in a common channel producing single branches divided by straight unbranched sections shaped by river flow concentration along the right valley side and formation single branches, divided by straight unbranched sections. It is found that at the village of Pogrebennoe the broadening of the floodplain to 60 km is accompanied by the formation of a bifurcated channel (Malaya and Gornaya Ob), the distribution of water discharge in the main channels (up to four) and by numerous floodplain channels connected with one another and with the tributary, the Severnaya Sos’va river. In this connection, the water discharge of the main branches downstream decreases (by as much as 5 % of the total discharge in the Malaya Ob), there occur changes in the morphology of the channels of the branches of the bifurcated channel and in the parameters of their forms and in the intensity of reconfigurations and caving; the number and shallowness of river bars increase. It is established that the morphodynamic types are different in the common channel and in the branches of the bifurcated channel. The common channel is represented by one morphodynamically homogeneous section, with an absolute predominance of single bifurcations; the branches of the bifurcated channel are mainly meandering, and only the Gornaya Ob in the section along the valley side forms single bifurcations. On the boundary of the Khanty-Mansi Autonomous Okrug - Yugra and Yamalo-Nenets Auonomous Okrug the river is concentred in two main branches (Malaya and Bol’shaya Ob). We obtained hydrological and morphological relationships between the parameters of channel bends of the channel of the branches of the bifurcated channel and the branches of single bifurcations and their discharge during floods. However, the relationships are unstable, because they are disturbed due to the variability in water discharge within one form and local conditions.

This paper considers periglacial sediments of the high accumulative Abalakh plain located in the interfluve of the Lena and Amga rivers (Central Yakutia). The genesis of loose deposits is determined, and the role of various sedimentation processes in their formation is revealed. Results were obtained on the basis of the cryolithological description of 94,5-meter borehole drilled in 2018. An analysis was made of the degree of roundedness and frosting of the surface of quartz grains. Diagnostic elements on the particle surface characteristic for different sedimentation processes are identified. An assessment of the relationship in the composition of quartz and feldspar grains was made. It was established that the layer under consideration has an alluvial (Tobolsk and Samara-Taz horizon) and lacustrine-alluvial genesis (Zyryanka horizon). It is pointed out that aeolian processes were also involved in sedimentation of the Tobolsk horizon. The source for deposits in the profile of the Abalakh plain was provided by loose deposits of short-range transport which were processed in the fluvial environment. Evidence for post-sedimentation processes of frost weathering was discover in deposits of the Zyryanka Samara-Taz horizons. It was established that loamy deposits of the ice complex were produced as a result of a complicated set of processes including frost weathering, aeolian transportation in a suspended state, and accumulation in stagnant basin conditions.

This paper presents the results of studies aimed at identifying statistical relationships between the landscape structure and the variability in Siberian stone pine (Pinus sibirica) increments in the permafrost-hillocky northern-taiga landscapes of Western Siberia (Nadym river basin). Dendrochronologies of Siberian stone pine growing on frost mounds of different types were compiled. Principal component analysis was applied to obtain independent variables that describe the site and landscape structure of the territory. Cores from 512 trees growing on 23 frost mounds were analyzed. The methods used were as follows: crossdating, dendrochronological standardization, and elimination of monotonic trends for each tree. Results of the classification of Sentinel satellite images were used to calculate the proportions of lakes, forests, sparse forests, floating bogs and flat-hillocky peat bogs, with the radius of the vicinity of a frost mound of 100-2000 m. Correlation, dispersion and regression analyses were used in the analysis of the dependence of the median increment on the characteristic of the mound site and landscape neighborhoods. It is established that on high mounds the variability in increments is higher on tops than on slopes, whereas the situation is often the contrary on low mounds. It is also found that the tops and slopes of the frost mounds respond differently to climatic fluctuations depending on the landscape structure and the height of the mound: the close proximity of lakes reduces the variability of phytoproductive functioning on the summit surfaces. It was revealed that the sensitivity of Siberian stone pine growth to temperature fluctuations increases with an increase in the diversity of the facies structure caused by the development of thermokarst subsidence and cryogenic cracks.

In order to identify the features in the dynamics of the soil temperature regime during the post-fire reforestation of the subtaiga light-coniferous geosystems of the Tunka depression, a study was made of the demutation processes in the pine forests of the Badary urochishche the fires that occurred in 2010. As part of monitoring observations in 2011-2020, the specificity of rehabilitation of understory trees as well as of the shrub layer and live ground cover was determined. The period of appearance of the first shoots of undergrowth was noted; the projective cover of species of all forest-growing layers was estimated. By comparing the dominant composition of secondary succession biocenoses with natural plant communities, indicators of the prospects for successful reforestation were identified. An analysis was made of 10-year-long observation data on the soil temperature regime from the surface to a depth of 3.2 m was carried out at the selected sites. Measurements were made all year round in an automatic mode using atmospheric-soil measuring systems. The differences between the soil temperatures on the disturbed and natural sites, which vary over a year, were revealed. Open soils on the site affected by fire are warmer in the summer and colder in the winter. Snow cover acting as a heat insulator on both sites reduces the differences. However, with late snow onset, the contrasts increase. During the observation period, a decrease in microclimatic differences was observed with the regeneration of vegetation cover, which indicates the reforestation of the temperature regime in the pyrogenically disturbed area. The results obtained at this stage, and also the continuation of the monitoring are applicable to the analysis of pyrogenic transformation of subtaiga light-coniferous geosystems in the south of Eastern Siberia and the forecast of post-fire reforestation of light-coniferous forests of the Tunka depression, taking into account regional specifics. The continuation of comprehensive monitoring will allow for a more detailed assessment of the regeneration of the landscape and climatic conditions of the territory in the future.

This article presents a comparative description of the thermal springs occurring on the coast of the Sea of Okhotsk, in the Priokhotye region. In the northern segment of Priokhotye, their groundwater is salty and brackish, mainly of the chloride class. Only one thermal spring (Khiimskii) is a freshwater spring. The water temperature varies from 22 to 63 °C. In the western segment, the water of the thermal springs is fresh, of the bicarbonate class. It is established that the thermal springs are associated with Quaternary dikes of alkaline basalts. The composition of thermal waters is governed by changes in climatic and permafrost conditions, and by fluctuations in the level of the Sea of Okhotsk in the Late Pleistocene-Holocene time. A consequence of these processes in the northern segment of Priokhotye was the introduction of thalassogenic waters to the bowels of the earth 18-9 thousand years ago. In the zone of their contact with the heated dikes of basalts, ascending jets of thermal chloride water appeared. In the western Priokhotye, the conditions in the Late Pleistocene-Holocene period were favorable for the formation of an extensive zone of fresh groundwater. Its contact with high-temperature dikes gives rise to thermal waters, the composition of which is close to the cold waters of the zone of active water exchange. The process of formation of thermal water springs in the valleys of watercourses takes place in two stages. First, the rising thermal jets are dispersed in the zone of active water exchange. Newly formed minerals colmate cracks and pores, forming a heat-removing vent. In the second stage, this vent contributes to the emergence and functioning of the thermal spring.

The need to seek new ideas and approaches in studying the cyclic nature of planetary and regional water exchange is substantiated. Based on systematizing available data and results obtained by this author, an analysis is made of the role of interphase transfers of natural waters in the formation of water exchange cycles. It is stated that the effect of phase mixing is inherent in natural waters. This effect is responsible for the unity of natural waters, and for a high intensity of their interphase transfer. Such a methodological approach was used to specify the scheme of climatic (hydrological) cycle of natural waters. In addition to the known atmospheric (atmogenic) cycle, cryohydrogenic, atmolithogenic, glaciogenic and cryolitogenic cycles have been identified as well as estimating the mass of water annually involved in these cycles, the intensity of water exchange in each cycle and the output of energy liberated or spent. Implementation of this scheme would provide an opportunity to more purpusefuly study water resources and various water exchange cycles.

Using instrumental observation data from meteorological stations located in the Southern Urals, a comprehensive fire hazard index and a forest fire hazard index for the 1978 to 2020 warm season (May-September) were calculated. The analysis was based on the daily values of surface air temperature, amount of precipitation, dew point deficit, average wind speed, as well as gain and number of days after the last rain. A correlation analysis between critical values of fire hazard indices and the forest fire actual data was carried out, revealing a close relationship between the extreme values of fire hazard indices and abnormally hot years. Fire hazard indices reflect the set of meteorological conditions conducive to the occurrence of fires in different ways. The forest fire hazard index, in contrast to the fire hazard complex indicator, in addition to the meteorological index, takes into account environmental factors. The calculated values of fire hazard indices were structured in the form of a database that can be used in meteorological forecasts to assess and predict fire conditions based on weather conditions. Comparison of the present data with results of wildfire space monitoring from the Terra-MODIS satellite are presented. An increase in dangerous meteorological conditions from 1995 to 2000 and a decrease in the number of days with critical values of fire hazard indices from 2000 to 2005 were established.

A method of aesthetic assessment of coastal landscapes surrounded by mountains at the regional level is suggested. Assessment and mapping of aesthetic resources of the territory are based on an understanding that viewing points and perceived landscape sceneries form an aesthetic system based on the geographical location. An aesthetic assessment was made by using geo-referenced landscape photographs taken during field investigations, and from the Panoramio web service database for 11 complex indicators characterizing the perception conditions of sceneries as well as their structure. The analysis of the landscape diversity of open and closed landscape scenes was carried out in a differentiated manner. The landscape diversity of open and semi-open scenes is determined by a combination of the ruggedness of relief and contrast of vegetation cover, while the differentiation of closed forest landscape scenes with a near perspective is based on the characteristics of the elements and components of the enclosing natural landscape (composition and density of the forest stand, the presence, abundance and height of the shrub layer, and the height and variety of ground cover). The assessment of complex indicators was carried out by using a three-dimensional model of the study area in Google Earth Pro, based on thematic layers imported from the Quantum GIS project (satellite images, digital elevation model SRTM, landscape typological and forest inventory maps, database of landscape photographs, etc.) with due regard for the obscuring role of vegetation cover. The contours of the landscape typological map at the level of groups of facies at a scale of 1:500 000 are used as mapping units. The score is assigned to the area from which the landscape is observed.

This study is concerned with the selection of optimal territories for installing solar photovoltaic power stations. The relevance of the research done is explained by the fact that electric energy generated by converting total solar radiation on a horizontal surface consisting of direct and diffuse components of PV cells has low output power; therefore, it is necessary to identify areas with a high power factor for more efficient power generation. However, due to the low efficiency of PV panels (14-18 %) and the low intensity of total solar radiation on a horizontal surface, a large installation space is required to achieve a certain power level. Due to the high cost of installing solar power plants, a comprehensive systematic assessment of the geographic factors of the region is required to select the most suitable location. Our selection of the Nakhchivan Autonomous Republic as the study area is explained by the fact that the radiation level is high compared to other regions of Azerbaijan (1220-1699 kW h/m² per year), and the number of hours of sunshine per year exceeds 2500. Since the creation of solar power plants in regions with high values of total radiation on a horizontal surface depends on technical, economic and environmental criteria, descriptive criteria are used to determine the optimal areas. The Analytical Process Hierarchy (AHP) model, based on Multi-Criteria Decision-Making (MCDM) methods, was used to identify suitable locations for solar power plants. In the first phase of the study, seven criteria were analyzed to determine suitable locations: total solar radiation on a horizontal surface, slope, land use, buffer distance from areas with high annual solar energy potential to residential areas, proximity to substations, motor roads, and power lines. In the second stage, the level of accessibility and suitability of areas within the framework of certain criteria was determined using the Weighted Overlay tool in Geographic Information Systems (GIS). In the second stage, using the weighted overlay tool in geographic information systems (GIS), the level of suitability of territories was determined according to certain criteria. As a result, of the study, it was concluded that 9,5 % (510 km²) of the land of the Nakhchivan Autonomous Republic has high suitability, 12 % (645 m²) - medium suitability, and 24 % (1290 km²) - low suitability for placing solar power plants. The remaining 54.5 % (2930 km²) of the region belongs to the territories that are not suitable for use due to low radiation, high slope, the presence of protected areas, settlements, agricultural areas and poorly developed infrastructure. Optimal locations cover mainly the southern and eastern parts of the region.