Within the areas of Ulakhan-Kurung-Yuryakh and Bestyakh of the Malo-Botuobinsky district, and in the Syuldyukar kimberlite field of the Ygyattinsky district, the carbonate-terrigenous deposits of the Upper Cambrian period revealed signs of ancient formation-oxidation in the gray-colored and coal-bearing, terrigenous carbon-Permian deposits, and fractured formation-oxidation commonly found on rocks of the underlying carboniferous weather crust. The data on the distribution and correlation of U and Th, Sc, and V confirmed the formation of the oxidation zone. The ore-forming significance of ancient infiltration hypergenic processes was confirmed by X-ray fluorescence analysis of Sc concen- tration in the Сarboniferous and Triassic-Jurassic weathering crusts, and the Late Paleozoic sediments, in the Ulakhan-Kurung-Jurassic area, the Syuldyukar and Nakyn diamond-bearing fields. In the latter, we identified promising Sc ore occurrences in the ancient weathering crusts developed by kimberlites and Middle Paleozoic basites. The series of Sc ore occurrences are of particular interest in the diamond mining area of Nyurbinsky GOK AK ALROSA (PAO).

In this study, we aimed to investigate the fundamental problem of identifying the role of lithological and paleogeographic settings on ancient platforms during the development of diamond-forming systems at the turn of the Middle Paleozoic (D3–C1) tectonic and magmatic reconstruction. The main focus was on the stratigraphy of the Carboniferous (Mississippian) deposits, the paleogeographic conditions of their accumulation, and their diamond-bearing reservoirs. The lithological and paleogeographic maps provided in this article show the locations of the sedimentary basins and other landscape zones, which allow the identification of demolition areas of terrigenous materials and delineate attractive areas for diamond prospecting activity.

The analysis of mineralogical information has enabled the development of a novel mineralogical zoning method using GIS and statistics. The proposed method was applied to the Ygyatta Region located within the Yakut Diamond-bearing Province. A set of mineralogical characteristics was chosen to examine the information content and productivity of the terrigenous collectors, providing an exact identification of the development areas of the deposits and the locations of their primary sources during medium-scale forecasting. The developed GIS-integrated database of the mineralogical passports of mine workings was based on the identification of background and anomalous parameters in the mineralogical field. The latter, within the Ygyatta Region, was delineated using ModelBuilder. The proposed method demonstrates the ability to contour mineralogical taxa of the “node” and “section” ranks within the Ygyatta Region, leading to the identification of six mineralogical nodes and fifteen mineralogical sections. This method can be effective for medium-scale zoning, based on mineralogical data from other diamond-bearing areas.

In this study, we reviewed and summarized the data on permafrost and groundwater areas of Central Yakutia to understand the formation and distribution of subpermafrost mineral waters of sodium bicarbonate and chloride-bicarbonate types, and to evaluate their potential use for medical purposes. Analysis of the data indicated that these low-mineralized groundwaters are basic analogues to the Maykop and Karachi mineral waters, with no particular bioactive components. These mineral water types contain 400 to 1200 mg/dm3 bicarbonates, 100 to 600 mg/dm3 chlorides, 50 to 250 mg/dm3 (Karachi) and <50 mg/dm3 (Maykop) sulfates, 400 to 800 mg/dm3 sodium, and <10 mg/dm3 calcium and magnesium. The formation of sodium bicarbonate and chloride-bicarbonate type water in Central Yakutia is influenced by permafrost which promotes concentration of major chemical components under the cold temperatures and slow groundwater circulation. The study of minor and trace constituents indicates that the subpermafrost waters in the study region contain fluorine and lithium in excess of the drinking water standards but are potentially appropriate for balneotherapy. Further research on the bio-physiological effects of subpermafrost waters with elevated fluorine and lithium concentrations contribute to the development of the spa and health resort industry in Yakutia. Moreover, the study will expand the balneological spectrum of disease prevention and treatment for the benefit of residents of Yakutia and the adjacent regions.

The activity of forest fires has greatly increased in recent years in Central Yakutia. This can lead to the radical transformation of permafrost landscapes and their degradation. This study aimed to determine the effects of climatic conditions on forest fire activity in this area. We analyzed data on air temperature and rainfall during the fire season from 2000 to 2020. The total annual burned areas have noticeably increased since the 2000s. Forest fires covered an area of more than a million hectares in 2002 and 2011. This trend was associated with climate change. The mean annual air temperature in Yakutsk increased by approximately 2 °C from 2000 to 2020, while the summer precipitation decreased. Both air temperature and the amount of precipitation during the fire season affect the accumulation of dry combustible material under the forest canopy, which determines whether favorable conditions are created for the spread of forest fires over large areas. We showed which climatic conditions are typical for periods of high and low fire activity. We analyzed the climatic conditions of certain years with the maximum and minimum burnt areas. Fire activity in the study area depends on the climatic conditions at the beginning of the fire season. High fire activity occurs at very high air temperatures; however, the predominant role is the deficiency of precipitation. The study of the dependence of forest fire activity on climatic conditions is important for estimating the consequences caused by climate change in permafrost landscapes.

This article presents the results of geocryological studies of the Tokarikan and Guvilgra grabens of the Aldan Shield. Expedition research on the hard-to-rich region since 1996 has allowed us to determine the temperature regime, thickness, and nature of permafrost rock distribution and characterize its geocryological conditions for the first time. We have established that the lowest temperatures (up to –3.4 °С) are characteristic of peatmoss bog landscapes, whereas the highest (–0.5 °С) are for well-drained and watershed areas. The results of the measurements in deep wells, information on the process of drilling deep exploration wells, and the analysis of data on the thermophysical properties of rocks allowed us to estimate a permafrost thickness capacity that varied in the range of 40–260 m. The presented schematic permafrost and geological cross-sections and geocryological condition maps can be used to plan the industrial development of the territory.

In this article, an analysis of data of forest fires and climatic conditions in Central Yakutia was carried out for the period 2000-2020. The aim of the study is to determine the role of climatic conditions in the forest fires activity. In the study area, the activity of forest fires has greatly increased in recent years. Forest fires can lead to a radical transformation of permafrost landscapes, to their degradation. The total annual burnt areas have noticeably increased since the 2000s. In 2002 and 2011 forest fires covered an area of more than a million hectares. This trend is certainly associated with climate change. So, in Yakutsk, the mean annual air temperature from 2000 to 2020 rose by about 2°C. At the same time, in the last 20 years, a decrease in the amount of summer precipitation has been observed. The study of the dependence of forest fire activity on climatic conditions is important for estimating the consequences caused by climate change in permafrost landscapes. To achieve this goal, an analysis of data on air temperature and rainfall during the fire season was carried out in the work. The accumulation of dry combustible material under the forest canopy depends on these two factors. In turn, this determines whether favorable conditions will be created for the occurrence and spread of forest fires over large areas or not. The paper shows what climatic conditions are typical for the periods with high and low fire activity. We analyzed the climatic conditions of certain years with the maximum and minimum burnt areas for the period under consideration. The fire activity in the study area currently depends on the climatic conditions of the beginning of the fire season. High fire activity is formed at very high air temperatures, however, at the predominant role of the precipitation, more precisely their deficiency. This is the main conclusion of the paper.

The global navigation system allowed us to study the ecology of the brown bear (Ursus arctos) in Yakutia, its space use, and movements. Data on the activity of brown bear in the territory of the region after leaving the den are presented for the first time. The study period lasted for 55 days, during which we obtained 1424 locations and collected information on 52 daily scale movements of brown bear using a satellite collar. Analysis of the data showed that the area of the spring-summer home range of an adult male brown bear, calculated using the method of the minimum convex polygon with inclusion of 100% locations, was 463 km². According to the fixed core method, the size of the home range area was 354.2 km², including a core area size of 33.5 km². On average, a male brown bear moved 11.8 km per day for the entire tracking period (limit of 0.95-28.5 km). The highest indicators of the daily run by male brown bear were registered in the first (15.3±1.79 km) and second (15.5±1.68 km) ten days in June compared to other months.

In recent decades, a reduction in the number of sparrows has been observed throughout their wide distribution range. However, information on the distribution and abundance of sparrows in Northeast Asia is scarce. Monospecific sparrow populations have been identified in various settlements and towns in the Magadan Region, although there are occasional records of other sparrow species. Among monospecific populations, only tree sparrows breed settlements on the Tauy Bay coast, in Magadan, Susuman, Verkhny Seimchan, and Omsukchan, whereas only house sparrows breed in Evensk, Seimchan, and Ust-Omchug. The tree sparrow population in Magadan was estimated to be 2750 individuals over an area of 9.6 km². Their population density in winter, estimated by plot counts, varied between 200 and 384 individuals/km² in parts of Magadan with different housing types. We conclude by discussing the ways in which tree and house sparrows may spread across the area.

We investigated several intermountain depressions in lakes with diverse flora of aquatic vascular plants in the southeastern part of the Chersky Range. The study area was located between 63–64° N and 147–148.5° E, at approximately 800–1200 m a.s.l. We identified 48 species and three hybrids.Among them, the families Potamogetonaceae (13 species and 1 hybrid) and Ranunculaceae (7 species) were characterized by the greatest diversity. For the first time, Stuckenia subretusa was found in the Magadan Region, which is the southernmost locality for this species. In an ultracontinental climate with an average annual air temperature of –13.1 °С, Arctophila fulva, Eleocharis acicularis, Hippuris vulgaris, Potamogeton alpinus, Ranunculus gmelinii, R. reptans and Sparganium hyperboreum are widespread. The species composition of aquatic plants is most diverse in small lakes at altitudes of 750–850 m a.s.l. in the plain interfluve, where the rarest species in the Kolyma River Basin are found. At altitudes above 850 m a.s.l. the most diverse species were found in the smallest lakes located near the large lakes. Obligate aquatic plants (80 %; 41 taxa; 30 hydrophytes and 11 hydrohygrophytes) dominated the flora of the mountain lakes. Only 20 % (10 species) of the flora were represented by plants of excessively moist coastal habitats. Among the 30 hydrophyte taxa 11 species grew up to 1050 m a.s.l. and 19 species grew at 950 m a.s.l. We identified four species that were protected at the regional level. Stuckenia pectinata is included in the Red Book of the Magadan Region, and Isoёtes asiatica, Nuphar pumila and Subularia aquatica are included in the Red Books of the Magadan Region and the Republic of Sakha (Yakutia).

The temperature regime showed a statistically significant positive trend in Yakutsk during the period 1961–2021. Thus, climate warming in the region has led to minor phenological shifts in the seasonal development of the Allium species, which differ in amplitude, duration, and direction. However, statistical analysis did not show significant differences in the phenological cycles of A. schoenoprasum, A. senescens, and A. ramosum. In a climate that has been changing for 54 years, these species have retained stability in the timing of their main phenological phases. The most noticeable phenological response to climate change was noted in two species – A. prostratum, A. splendens, that respond with statistically significant shifts in the beginning of flowering period (A. prostratum, р = 0,0009), the end of vegetative period (A. splendens, р = 0,0137), duration of prefloral period (A. prostratum, p = 0,0162) and duration of vegetative period (A. splendens, p = 0,0298). We conclude that a slight shift in the timing of the main phenological phases in the five species of the genus Allium over 54 years suggests the inertia of the phenological response of the plants to climate change.

The aim of this study was to identify physiological and biochemical changes in seedlings of wild plants of Yakutia, grown from seeds, which have received a pre-sowing, super-weak constant magnetic field treatment of different magnetic flux densities. Review of literature sources allows us to conclude that the weak effects of low-intensity fields (nonthermal character) have not been studied sufficiently so far. The study was conducted on seeds from 14 different species of wild plants native to Yakutia. The seeds were subjected to different magnetic flux strengths of 0.2–4.0 mT for 24 hours and then were germinated on filter paper. The criterion for evaluating the effect of the super-weak constant magnetic field was the formation of a true leaf in seedlings (survival rate). The intensity of lipid peroxidation processes was recorded as a pro-oxidant reaction. The total content of low molecular weight antioxidants was determined as an example of the non-enzymatic antioxidant system. The activity of an antioxidant enzyme, superoxide dismutase, was determined. The effects of the super-weak constant magnetic fields were evaluated using regression and statistical methods. Based on the working hypothesis is that the formation of the present leaf is dependent on changes in the pro-oxidant-antioxidant equilibrium in the cells of the seedlings as a result of the action on them by the super-weak constant magnetic field as a function of the magnetic flux density. We showed that the survival rate of seedlings grown from the seeds pre-treated by super-weak constant magnetic fields of different magnetic flux density for 24 hours leads to the activation of lipid peroxidation and depends on the adaptation processes of antioxidant systems (the sum of low-molecular antioxidants and superoxide dismutase activity): simple compensation or hypercompensation. In the second case, the action of super-weak constant magnetic fields leads to an increase in the survival rate of seedlings by the criterion of the formation of the true leaf. The study is of significance for specialists in magneto-biology and researchers of plant antioxidant systems.

The purpose of this study was to analyze the protective function of Acer negundo L. by assessing the indicators of developmental stability by fluctuating leave asymmetry depending on the value of the influence of anthropogenic factors. The materials were obtained from 25 test sites on areas that differed in the degree of road transport impact in 2018–2021 in Irkutsk. The values of the indicators of the developmental stability of each test site were determined as the average of the coefficients of fluctuating asymmetry, considering the eight characteristics of the leaves collected from them. These values indicate that A. negundo is sufficiently resistant to anthropogenic impacts, particularly the effects of emissions from road transport, compared with other types of phanerophytes involved in the landscaping of urbanized areas. The coefficient of weighted average of this indicator between sites in recreational areas and along highways was 1.33. The correlation coefficient between the values of development stability and the distance of growth of A. negundo from highways was r = –0.64±0.18, which confirms the average connection between these characteristics. Analysis of variance was used to assess the stability of tree development in four classes of traffic intensity (high, medium, low, and absent), determined through a correlation ratio, the level of which n = 0.70 demonstrates a high level of connection. To limit the implementation of A. negundo in the local flora, it is recommended that measures be gradually implemented to remove it from parks, squares, gardens, and adjacent territories, with the replacement of woody vegetation species that are well adapted to grow in these habitats.

In this paper we present the principles for a new method of quaternion factorization of the equilibrium equations for the transversally isotropic elasticity. Natural and artificial materials have anisotropy of physical properties. Many of them have transversal isotropy of elastic properties. Transversally isotropic materials are used in many technologies and industries, for example, in rock mechanics under permafrost conditions. Mathematical description of such materials involves the model of a transversally-isotropic material with 5 independent elastic constants. The equations of this model are more complicated than those for isotropic elasticity, and their analysis causes much more difficulties. One of the methods for analyzing such equations is factorization, i.e. reduction to the solution of simpler first-order equations.

Elastomeric materials for sealing devices operated in the Far North, including the Republic of Sakha (Yakutia), must be resistant to working environments and have frost and wear resistance with acceptable physical and mechanical properties. Some of the listed properties are mutually exclusive and are not always achievable in materials based on individual rubber. Thus, one promising method for sealing elastomeric materials is the use of rubber mixtures. In this study, model blends based on nitrile-butadiene (BNKS-18), butadiene (SKD), and isoprene (SKI-3) rubbers were studied. Nitrile butadiene rubber was chosen as the component of the mixture responsible for resistance to working environments, and diene rubbers (SKD and SKI-3) were chosen as the components responsible for frost resistance. The addition of SKI-3 also suppressed the crystallization of SKD butadiene rubber. An increase in the BNKS-18 content enhanced the physical and mechanical properties and resistance to wear and non-polar oils. A decrease in lowtemperature properties and resistance to polar oils was also observed. Additionally, studies of the structure of the obtained materials by atomic force microscopy were carried out, which proved the uniformity of the distribution of particles of the dispersed phase, the size of which did not exceed 1-5 μm. The optimal ratio of butadiene-nitrile to diene rubbers was 70:30 phr. At this ratio, the obtained elastomeric materials meet the requirements of sealing materials for operation in cold climates.