In the Kularsky gold-bearing area, where 170 tons of gold were extracted from placers, primary gold deposits have not been well studied; therefore, their development requires detailed geological analysis including the study of rock metamorphism. A large Ulakhan-Sis anticline composed of Permian carbonaceous-terrigenous rocks is found on the northwestern flank of the Kular-Nersky folded belt of the Verkhoyano-Kolyma orogenic region. In this article we describe the material composition of carbonaceous-terrigenous rocks prevalent in the northern part of the Kularsky district. The degree of their postdiagenetic transformations varies from metagenesis in Triassic rocks to muscovite-chlorite and biotite subfacies of the greenschist facia of metamorphism in Permian rocks of the Ulakhan-Sis anticline. As the transition from metagenesis to muscovite-chlorite and biotite subfacies of metamorphism the degree of recrystallization of rocks, the grain sizes of the recrystallization of clastic quartz and the width of newly formed muscovite flakes are increasing, monazite, ilmenite, biotite flakes appear in rocks. These changes occur before the completion of formation in the rocks of the S₁ slate cleavage.

After the formation of the latter, mainly before the appearance of a later crenulation cleavage S₂, crystallization of pyrite occurs in the rocks. Porphyroblasts of biotite and magnesiosiderite appear during the formation of a crenulation cleavage S₂. The appearance of biotite during the formation of the S₁ and S₂ cleavages may correspond to the theories about the two-stage metamorphism of the rocks of the area. Thus, further metamorphism studies in this region are required.

The replenishment of the mineral resource base in the Daldyn-Alakit diamond-bearing region (Yakutia) is associated with the identification of new primary diamond deposits within the Alakit-Markha kimberlite field (AMKF). The development of Paleozoic terrigenous carbonate deposits within the field is complicated by intruded bodies of traps, thus creating a challenging geological task for prospecting. This study aimed to investigate the features of the deep structure of the Earth’s crust, including sedimentary cover, and their relationship with the manifestations of kimberlite magmatism to isolate objects of kimberlite magmatism by geophysical methods in an area with a very complex geological structure. The results of predictive prospecting studies using magnetotelluric sounding (MTS) conducted within the southwestern flank of the AMKF are considered from the standpoint of structural control of the placement of kimberlite fields and their bushes. Our findings show that the main factors controlling the manifestations of kimberlite magmatism at the medium-scale stage, and local studies include conducting inhomogeneities in the Earth’s crust located at the intersection points of the Daldyn-Olenek zone of deep faults with multidirectional tectonic disturbances and low-amplitude depressions complicated by structures of the opposite sign. Similar geological and structural prerequisites were established in the areas of development of kimberlite bodies identified by geological studies within the AMKF. Enhanced by favorable mineralogical and geochemical results, these prerequisites can be considered the main criteria for predicting new kimberlite bodies in a well-studied area. We specified the central part of the studied MTS profile based on the geological, geophysical, mineralogical, and geochemical data, which is the most promising for forecasting and identifying new diamond-bearing objects in the category of individual kimberlite bodies.

In this article, we discuss the age range for the formation of the Obnazhennaya kimberlite pipe (Kuoyka field, north-eatern Siberian platform) considering the recent unique discovery of a representative of the Toarcian-Early Aalenian (end of the Early–beginning of the Middle Jurassic) belemnites along with the revision of previously known belemnites of the Upper Jurassic–Lower Cretaceous age. We investigated the specifics and general genesis of the facies in the complex vertical structure of the sections. In addition, we assessed the role of the ancient Kimmeriyan, Dunlap, and New Cimmerian phases of Cimmerian tectono-magmatic activation in the stabilization of the Kuoika and Khorbusuon kimberlite fields. Moreover, a new model of the eruptive system of Mesozoic kimberlite fields was considered. The existing paleogeographic schemes of the Toarcian-Early Bathonian interval northeast of the Siberian Platform have been corrected. The study location provides important evidence of the disappearance scale of marine ingression traces in the geological record.

For the first time, shell cross-sections were made for the most ancient (Late Permian) representatives of the genus Otoceras. From these cross-sections, ontogenetic changes in the shell shape of O. concavum Tozer were reconstructed at size stages ranging from tiny to very large. A moderately wide shell with a moderately narrow umbilicus narrows intensely to its tiny size, becoming a narrow shell. At the stage of very small size, the shell expands, again becoming moderately wide, and the umbilicus narrows slightly, remaining moderately narrow. However, at small sizes, the change in these characteristics occurs in the same direction, but with increased intensity. Moreover, important changes are observed at the medium-sized stage, when the expansion of the shell stops and the umbilicus becomes narrow. At the end of the studied ontogenesis, the morphological development of the mollusk was aimed at the formation of a moderately narrow shape with a very narrow umbilicus. Of the variety of shell shapes previously established among ammonoids, numbering 35 types, representatives of the species O. concavum throughout the studied ontogenesis had only three: subdiscocone, tumaricone, and pachycone. Finally, the constructed ontogenetic model clearly demonstrated the features of the development of the cross-sectional shape of O. concavum shells during their growth, emphasizing ontogenetic trends in changes in the most important parameters of the shell. We conclude that the identified transformations of the shell shape contribute to the diagnosis of small-sized Otoceras, and can serve as the basis for the subsequent reconstruction of the morphogenetic development of the family Otoceratidae.

Changes in the Arctic have global consequences. An increase in air temperature and a change in the cold period can affect vulnerable ecosystems with a permafrost lithogenic base in the Yakutia Arctic region. In this study, we specified the dates of the beginning and end of the cold period in spring and autumn for two multi-year periods (1961–1990 and 1991–2022) of the northwestern and northeastern parts of the Arctic zone in Yakutia. We calculated the temperature difference and rate of change (C°/10 years) for 1960–2022. We used meteorological series according to the “RIHMI-WDC” data: st. Olenek (Oleneksky ulus), st. Zhigansk (Zhigansky) st. Chokurdakh (Allaikhovsky) and st. Srednekolymsk (Srednekolymsky). For the period 1991–2022 in the northwestern part of the Arctic zone in Yakutia, a reduction in the cold period was observed due to an earlier onset in spring (May: 4 days at Olenek station and 6 days at Zhigansk station) and in the northeastern part-later autumn (September: 3 days at Chokurdakh and Srednekolymsk stations). The results of our study indicate that in April, the difference in the average air temperature between 1961 and 1990 and 1991–2022 at all stations is higher than in October. The only exception is the information obtained according to st. Chokurdakh (October–2.6°C, April–2.1°C). The rate of change in air temperature (°С/10 years) for the period 1960–2022 at the beginning of the cold period (October), it manifested itself to a greater extent in the northeast of Yakutia (Srednekolymsk station – 0.7 °C/10 years, Chokurdakh –°C/10 years). In the middle (January – 1.1 °С/10 years) and the end (April – 1.0 °С/10 years) of the cold period, the maximum rate of air temperature change was noted in the north-west of Yakutia according to the data of st. Olenek.This study is necessary for the verification and selection of representative climate models, the analysis of the spatiotemporal variability of the cold period, and the forecasting and contribution to the overall dispersion of soil temperature.

The mixtures of sands and nanoclays are used to isolate municipal and industrial solid wastes. Compared with natural clayey soils, these mixtures are characterized by homogeneous composition, workability, and low compressibility. This study investigated the effect of freeze–thaw cycles on their permeability. The mixtures of four sands and a saponite clay suspension generated by diamond ore processing were studied. The mixtures were prepared on the basis of 4 % and 8 % clay from sand weight. The tests were performed using an apparatus consisting of four devices for measuring frost heave and permeability, which were placed in containers with water. The water level was decreased gradually to ensure sample freezing or increased to ensure sample thawing. The frost heave of the mixtures with 4 % clay was 10.0–16.4 % under an external load of 2 kPa, and the five freeze–thaw cycles resulted in an increase in the hydraulic conductivity by 2.0–4.7 times. The mixtures with 8 % clay were tested under a load of 12 kPa, because of their high frost susceptibility. The hydraulic conductivity increased by approximately the same value as in the first case, i.e., by 1.2–2.0 times. The experiments have shown that the examined mixtures are suitable for isolating wastes. However, to eliminate the above effect, a waterproof liner should be covered with inert soil, which would reduce the depth of frost penetration and apply the load on it.

Modern research on icing is focused on regional patterns of its distribution and compilation of its catalogs from different regions. This study discusses new approaches to mapping icings using NDSI based on Sentinel-2 and SAR images of Sentinel-1. Using the polarimetric decomposition of a backscatter signal and unsupervised classification, we identified the contours of the icings in May 2018–2022, and calculated their areal extent. We compared the areas of icing using both methods, and correlated the data. Only 10 % of all icings showed a difference of less than 10 % in the area values. It is located in river valleys where the boundaries of the icing field coincide with a flood plain, and their width is at least 100 m. The reflected backscatter signal at such objects is characterized by moderate or high entropy volumetric scattering. On the basis of the NDSI index, 237 icings were identified within the Chulman Plateau, with a total area of 134.44 m². We assessed the main natural controls in the development of the icing process. This is the initial stage of studying icings in the southern part of the permafrost region. Furthermore, we plan to classify icings according to their sources of nutrition and to detail the patterns of icing formation in this region. The research results will make it possible to predict the formation of icing during engineering construction and evaluate groundwater resources.

This article analyzes the problems of correlating the space within which the Russian Federation’s special state policy is implemented, considering Russia’s international obligations, to the actual status of the Arctic territories. The boundaries of the Arctic zone of the Russian Federation (AZRF) and the territories specified by the Conservation of Arctic Flora and Fauna (CAFF) working group of the Arctic Council are only partially coincident and vary in different regions. This discrepancy can be explained by the lack of uniform criteria for the identification of the southern border of the Arctic zone, while international projects aimed at preserving the natural environment and biodiversity in the Arctic are being implemented in these territories. A number of territories have been proposed for inclusion in the Arctic zone as part of the final stage of the Russian Arctic. It is important to define the Arctic zone in order to address the problems of protecting the environment and biological resources of the territory and ensuring the social and economic well-being of the Arctic population.

The stability of the biota in the Arctic regions under climate change and increasing anthropogenic burdens is influenced by the adaptive potential of its representatives. This study aimed to assess the adaptive potential of dwarf shrubs (Betula nana, Vaccinium uliginosum, and Salix polaris) in the flora of West Svalbard on the basis of their morphological and anatomical features and total leaf lipid fatty acid content. All species have similar leaf anatomy characteristics: small leaves, dorsoventral structure with clear differentiation into palisade and spongy mesophyll, which ensures their growth in the Arctic. However, S. polaris is characterized by high volumes of the stomatal apparatus, an amphistomatic type of leaf, a high palisade coefficient, a large volume of mechanical leaf tissue, and a high content of unsaturated fatty acids (UFA). These features provide high functional activity, passage through all stages of ontogenesis, and a wide distribution of the species in West Svalbard. In contrast to S. polaris, B. nana and V. uliginosum are characterized by a decrease in leaf area, a decrease in the palisade coefficient, and a hypostomatic leaf type, which, combined with an increase in the diversity of “secondary” UFA, as well as the lack of generative development, may indicate a higher level pressure of extreme conditions for the species. Thus, these features may explain their limited representation in the ecotopes of West Svalbard. In contrast to B. nana and V. uliginosum, the higher adaptive potential of S. polaris ensures its greater stability in conditions of changing habitat. All studied dwarf shrub species can be used as markers for monitoring the environment in the high Arctic.

This article presents data on the variability of morphological features and cytogenetic indicators in Scots Pine (Pinus sylvestris) growing in areas affected by the industrial activity of the Sayanogorsk Aluminum Plant (SAP). We demonstrated that in polluted plots located at a distance of 1 and 5 km from the plant, the reproductive organ indicators of pine significantly decreased, germination energy and viability decreased, and needle necrosis frequency increased compared with the control. A significant increase in the frequency of class III needle necrosis in experimental plots by 7.2–8.6 times compared with the control, as well as a decrease in germination energy and seed germination in experimental plots by 1.1 and 1.3–1.5 times indicates the strong negative impact of SAP emissions on pine. Mitotic index and frequency of chromosomal aberrations in the apical meristem cells of Scots Pine seedlings were determined by cytogenetic analysis. A considerable reduction in mitotic activity by 1.35 to 0.8 times was observed in the meristem cells of Scots Pine growing in experimental plots, compared with the control plot. A tendency toward an increase in the frequency of abnormal mitoses of Scots Pine in the experimental areas was observed. Thus, the data obtained made it possible to assess the condition of Scots Pine in areas exposed to the influence of SAP.

The rational use of wild reindeer (Rangifer tarandus L., 1758) based on reliable data on the number, distribution, age-sex composition, and herd size of the population is a challenging problem for hunting management. The purpose of this study was to characterize the current state of the Lena-Olenek tundra wild reindeer (LOWR) population. The counting of LOWR was based on the aerial census conducted from July 10 to 12, 2018; coordinate data from the GLONASS/Argos satellite tracker collars; stock materials from previous aerial surveys in the tundra of Yakutia. From the data obtained, the livestock of the LOWR was estimated to be 83,260. We specified that deer are housed in three distinct groups: broodstock, mixed, and male. The main livestock in the LOWR were females (44.2 %), calves (22.4 %), and juvenile animals 1–2 years old (17.5 %). Over 32 years, there was a decrease in 62.2% in the number of adult males and an increase in the number of fingerlings and juvenile animals. Since the middle of the last century, there has been a gradual increase in the number of LOWR from 21,000 to 95,000 deer in 2009 and a slight decrease to 83,200 deer in the last decade due to the exclusion of Taimyr reindeer migrants. The results of this study can be used to rationalize the use of wild reindeer resources and the allocation of quotas for production. Further census work will make it possible to monitor the state of the population over time.

The steppe bison (Bison priscus) is one of the most widespread and numerous representatives of the mammoth fauna. However, the features of the extinction of steppe bison at the end of the Pleistocene and their replacement by modern forms of the American bison (Bison bison) and European bison (Bison bonasus) have not yet been fully studied. Thus, complete skulls of fossil steppe bison are of great interest for studies on taxonomy and kinship relations in the genus Bison. This article presents the results of a study of the finely preserved skull of a fossil bison found in the Verkhoyansk district (Yakutia). This skull was compared by its morphological and osteometric features with other bison skulls, which were found at different times and locations in Upper Pleistocene deposits, as well as with the skulls of modern American bison Bison bison from the collection of the Zoological Museum of the Lomonosov Moscow State University. Standard morphometric indicators of bison skulls and horns were obtained using the Skinner and Kaisen measurement methods. Analysis showed that skulls of Bison priscus from Late Pleistocene sediments of Yakutia, according to most parameters, correspond to the maximum size of modern American bison Bison bison or even larger than the latter. The horns of bison from the Late Pleistocene are 1.5–2 times larger in size than the horns of modern bison and are comparable to those of the Middle Pleistocene long-horned bison B. p. crassicornis Richardson (=longicornis). The disproportion in the size of the skull and horns of the Late Pleistocene bison is due to their habitat in the open landscapes of the Arctic steppe. The morphological uniqueness of the steppe bison of the Late Pleistocene in Yakutia has prospects for further research, because it deserves to be identified as an independent taxon (subspecies), which is relevant for regional paleontology and stratigraphy.

In this article we provide the results of the synthesis of graphene films and discuss their potential applications in electronic structures. Graphene films were synthesized on copper foil using the CVD method at 1050 °C. During the initial stage of synthesis, graphene domains with hexagonal shapes and an average size of 10 μm were formed. The orientation and size of the graphene domains are based on the synthesis parameters and the copper foil. As the synthesis time increases, domain cross-linking occurs, resulting in polycrystalline continuous graphene film formation. Graphene films have areas up to 100 cm² and thicknesses ~ 1 nm to 5 nm. To measure the Raman spectra, graphene films were transferred to SiO₂/Si substrates. Graphene films exhibit an intense 2D peak that significantly exceeds the G peak of crystalline graphite. Flexible transparent conductive touch panels were created on the basis of the grown graphene films. A lamination method has been used to create graphene films that can be transferred from copper foil to polymer substrates. A laboratory touch screen with a graphene film acting as a capacitive touch sensor was constructed on the basis of the transferred film, and transparent electrodes for molybdenum disulfide-based photosensitive elements were also created. Resistive humidity sensors based on graphene films were developed and transferred to SiO₂/Si and epoxy/Si substrates. The graphene humidity sensor has a low response, high temperature stability, and is highly reliable.

In the development of polymer composite materials, it is crucial to use various technological methods for introducing fillers into the structure of the base polymer, by different activation technologies of energy exposure. In this study, the processes of structure formation of polymer composite materials based on polytetrafluoroethylene and discrete hydrate cellulose carbon fibers, depending on the production technology, were investigated by scanning electron microscopy. We considered joint mechanical activation of components and passing the powder mixture through laboratory rollers. To understand the processes occurring in the friction process of the developed PCM, surface studies before and after friction by infrared spectroscopy were carried out. We found that during the friction process, depending on the friction mode, the spiral conformation of the PTFE macromolecules changes. An increase in the sliding velocity and the load during PCM friction leads to a change in the spiral conformation of macromolecules with a transition from 13₆ to a more stable conformation 15₇. We also found that the combination of technologies for joint mechanical activation of components and rolling of a powder mixture are technological techniques that can increase the structural activity of discrete hydrocarbons and intensify the adhesive interaction at the polymer-filler phase interface, which leads to an increase in the resistance of composites to creep and wear. The developed technological approaches can be used in the production of fluorocomposites containing not only carbon but also other types of fibers.