Home – Home – Jornals – Russian Geology and Geophysics 2025 number 6

Caldera-forming explosive volcanism is the most dangerous natural hazard, which has catastrophic consequences to the life, humans and their economic activities. The paper presents a summary of published and original data on the late Pleistocene-Holocene caldera-forming volcanism within the Great Kuril Arc (GKA) available to the recent times. The published data reveal that formation of explosive calderas occurred throughout all GKA segments in the late Pleistocene and Holocene. Most frequent it was in the Southern and Central segments of GKA, where it meets the back arc Kuril Basin. The majority of the studied calderas appeared in the late Pleistocene 50-12 Ka and early Holocene 8-6 Ka. Intensive caldera-forming volcanism in GKA could be contemporaneous to similar events in the East-Kamchatka Volcanic Belt and Southern Kamchatka. Caldera eruptions of GKA in the late Pleistocene and early Holocene were linked to evolution of large reservoirs of predominantly dacitic magmas, which were generated by partial melting of metabasitic protholiths in the shallow crust (3-12 km) at 810-930°C. Rhyolitic melts of these magmas were saturated with H₂O, CO₂, sulfur compounds, and probably other gaseous species. This caused shallow degassing at the pre-eruptive stages of the magma reservoir evolution. The study rises problems, which solution would provide a basis for effective prediction of catastrophic volcano explosions and monitoring of active GKA caldera volcanoes.

The junction zones of mountain ranges with adjacent intramontane basins and foreland basins, developing under regional compression and transpression, are concentrators of key seismogenic faults. In this case, two counter-dipping systems of reverse faults and thrusts develop, which leads to the formation of positive (forebergs, pop-up structures, fault and tectonic scarps, and fault-related folds) and negative morphostructures (pop-down structures) in the marginal parts of sedimentary basins. As a result, the marginal parts of the basins are involved in the uplift. This results in the gradual growth and expansion of mountain ranges, accompanied by a corresponding reduction in the size of intramontane basins, indicating that the upper portion of the Earth’s crust experiences shortening. However, the mechanisms of occurrence of conjugate fault systems remain not fully understood. The mechanisms of such deformations in the upper crust are investigated under lateral compression of the rock mass using two-dimensional numerical modeling. The problem is solved in the elastic-plastic approximation using the Drucker-Prager-Nikolaevsky model with a non-associated flow law. In all models, regardless of the number of layers, reverse faults and thrusts with direct and reverse dips relative to the direction of horizontal compression are formed. As a result, positive and negative structures are formed in the model’s top surface relief, which are analogs of the corresponding natural morphostructures. The resulting data show that the development and configuration of localized shear bands corresponding to reverse faults and thrusts are affected by elastic-strength parameters, friction at the base of the model, and conditions on its lateral boundaries. It is revealed that, in the case of a multilayer medium, a single stage of deformations may result in a multitiered system of localized shear bands, characterized by different slopes and limited only by a specific layer. Special attention is paid to models that exhibit interlayer slipping, driven by varying relative movement rates of the layers due to differences in the elastic and strength properties of the rocks, thereby leading to the development of backthrusts in the upper part of the section that are not associated with the base of the model. Backthrusts are most often observed in the upper part of the model. Block inclusions at the base of the models, regardless of their strength properties, can affect the spatial localization of multidirectional localized shear bands that arise at their boundaries. The numerical modeling data allow for a better understanding of the relationship between the mechanical properties of rocks and sediments with the features of the development of faults, thrusts, and backtrusts.

The study focuses on determining the position of the southern boundary of the Okhotsk Plate based on the analysis of seismicity distribution in the Hokkaido and Honshu regions as well as adjacent territories according to the Japan Meteorological Agency (JMA) data for a period of 1998-2022. The seismicity distribution data are compared with regional seismic tomography models and the distributions of the directions of principal seismotectonic deformation axes according to data on the focal mechanisms of strong ( M_w > 4.7) earthquakes using the International Seismological Center (ISC) data for a period of 1976-2022 and other recent geological-geophysical characteristics, such as gravity field heterogeneities, crustal thickness, volcanic manifestations, etc. It is revealed that the southern boundary of the Okhotsk Plate actually passes along the southern tip of Hokkaido Island (through the Oshima Peninsula and Uchiura Bay) rather than along the Hidaka Ridge or through Honshu Island, as previously assumed by other authors.

We discuss possibilities of application of radon activity concentration variations in investigating changes in the stress-strain state of a rock massif. Based on the long-term radon monitoring at the South Kuril geodynamic polygon, the methodology for interpretation of soil radon activity concentration anomalies has been developed. A causal relationship between earthquakes and radon anomalies has been established. It is shown that tectonic events occur after the radon anomaly passes over the maximum level, and the reflection time depends on the distance between the observation point and the epicenter of the event. The mechanisms of formation of radon anomalies in the compression/extension zones are described.

The stored waste from processing Ni-Co arsenide ores of the Khovu-Aksy deposit (Republic of Tyva, Russia) is a unique geochemical system, in which the joint behavior of As and metals (Fe, Co, Ni, Cu, Zn, and Pb) under exogenous conditions can be directly traced. We have studied the mineralogical and geochemical specifics of the distribution of arsenic (from primary arsenides to newly formed phases) and associated metals in waste with a high As content (up to 4%) throughout the section of trench burial No. 3. These strata are characterized by a slightly alkaline environment with pH = 7.7 and Eh = 486 mV. Four horizons are distinguished in the section. According to elemental analysis (XRF-SR), As, Mo, Pb, Sb, Co, and Cu accumulate in horizon 2 (80 cm), whereas Cd, Zn, and Ni, in horizon 3 (110 cm). In the processed ores, nonmetallic (rock-forming) minerals are represented by quartz, calcite, dolomite, garnet, amphibole-chlorite aggregates, single grains of K-feldspar (Kfs), apatite, barite, and muscovite. Arsenic minerals are distributed extremely unevenly throughout the section and are absent from the soil horizon (horizon 4). Arsenic is found in the section as: (1) arsenic minerals, namely, safflorite with hovuaksite, conichalcite, scorodite, arseniosiderite, sarmientite, hörnesite, annabergite, and picropharmacolite; (2) isomorphic impurity in secondary products (iron hydroxides developed after pyrite, amorphous silica, and chlorite). The presence of carbonate minerals in primary ores and the applied technological scheme of ore dressing with purification of solutions from arsenic affect directly the secondary assemblage of arsenic minerals.

Experimental studies on modeling the diamond resorption processes during mantle metasomatism accompanied by oxidation process in solid-phase matrix in the presence of intergranular fluid have been carried out. The reaction conducted between diamond and periclase to form magnesite can be considered as prototype EMOD (enstatite-magnesite/olivine-diamond) or DCDD (dolomite-coesite/diopside-diamond) reactions. The experimental studies were conducted at a pressure of 6.3 GPa in the 1100-1400 °C temperature range under redox conditions corresponding to the WM (wüstite/magnesite) buffer. It was found that the reaction between diamond and periclase to form magnesite occurs only in the presence of 0.5-0.8 wt.% water at temperatures above 1200 °C. The morphology of diamond crystals partially dissolved by intergranular H₂O-fluid at f _O2 at the WM buffer level represents a typomorphic feature of diamond dissolution/resorption in water-containing carbonate and carbonate-silicate melts. The main microrelief elements of diamond dissolution forms are negatively orientated triangular etch pits on relict octahedral faces, shield-shaped or ditrigonal dissolution layers, and drop-shape hillocks. The obtained resorption rates at these P-T- f _O2 parameters indicate that the absence of diamond in kimberlites or low-grade potentially diamondiferous kimberlite pipes might be caused by oxidizing metasomatic events in the lithospheric mantle in the regions of kimberlite emplacement.

A synthetic analog of mourite (SM), (UO₂)Mo₅O₁₄(OH)₄(H₂O)₂, has been hydrothermally synthesized at 220 ºС and characterized using single-crystal X-ray diffraction, single-crystal and powder X-ray diffraction studies at non-ambient temperatures, X-ray photoelectron spectroscopy, infrared spectroscopy, thermal, and chemical analyses. SM is monoclinic, P 2/ c , a = 9.9063(6), b = 7.1756(4), c = 12.2105(7) Å, β = 102.496(6)°, V = 847.41(9) ų; the crystal structure has been refined to R ₁ = 0.043. The chemical composition of the SM is (the Mo₂O₅:MoO₃ ratio obtained from X-ray photoelectron spectroscopy, H₂O by stoichiometry; wt.%): Mo₂O₅ = 4.61, MoO₃ = 61.06, UO₃ = 26.95, H₂O = 6.76, total 99.38. The empirical formula calculated on the basis of 22 oxygen atoms per formula unit with Mo^V + Mo^VI = 5 is (U^VI_1.03O₂)[(Mo^VI_4.63Mo^V_0.37)_Σ5.00O_13.81(OH)_0.19](OH)₄(H₂O)₂. The crystal structure of SM contains UO₈, Mo1O₆, Mo2O₅(H₂O), and Mo3O₄(OH)₂ polyhedra that share vertices and edges to form layers linked by hydrogen bonds only. SM is stable up to 250 ± 10 ºС. Upon heating, continuous dehydration occurs between 160-250 ºС until the formation of amorphous products; crystallization above 450 ºС produces UO₂MoO₄, MoO₃, and UMo₁₀O₃₂. Below 250 ºС, thermal expansion of the compound is strongly anisotropic, with the maximal direction perpendicular to the plane of the layers.

Studying the spatial distribution of specific groups of marine invertebrates in the geological past and analyzing their geographic differentiation over time are crucial for understanding both their evolutionary patterns and the history of marine basin development. This study, based on modern paleontological and biostratigraphic data of the Boreal Triassic, refines the taxonomic composition and distribution of Ladinian ammonoids across various regions of the Boreal Realm. Zonal correlation on ammonoids of Ladinian deposits has been carried out for Northeast Asia, British Columbia, the Canadian Arctic Archipelago, northern Greenland, Svalbard, and Franz Josef Land, providing a chronological basis for comparative analysis of coeval ammonoid faunas. The qualitative and quantitative comparative analysis of ammonoid assemblages for different phases of the Ladinian Age has established that Northeast Asia consistently belonged to the Siberian Province of the Boreal Realm. The separation of the Canadian Province of the Boreal Realm occurred at the end of the constantis Phase due to the penetration of trachyceratids (genus Protrachyceras ) into the paleobasins of the Canadian Arctic Archipelago. Subsequently, starting from the maclearni Phase, the area of the Canadian province expanded due to the migration of Tethyan forms into the paleobasins of Svalbard. The migrations of trachyceratids, gymnitids, and lobitids into boreal paleobasins from the Tethys Ocean, as well as the dispersal of Boreal tsvetkovitids and nathorstitids into ecotonal and Tethyan paleowaters of British Columbia, were influenced not only by circumpolar currents but likely, by the lifestyle of ammonoids and their adaptation to a broader or narrower range of marine basin depths.

In evolutionary biology, the dominant idea is that the mechanisms of intraspecific evolution and speciation are the same, and intraspecific forms are, in essence, emerging species. The extensive literature on the evolutionists’ model species, the three-spined stickleback, allows us to verify whether this is so, and the analysis shows that although this fish, when living in fresh water, give a variety of forms that are morphologically very different from marine ones, postzygotic reproductive isolation between representatives of different forms does not usually occur. No such form of isolation has been found between populations from different parts of the species’ range. The adaptation strategy of the three-spined stickleback includes long-distance migrations that facilitate the inhabiting of newly emerging favorable habitats and the exchange of genes between populations, acceleration of selection, and a decrease in the probability of recombination of alleles of genes necessary for adaptation. This strategy does not facilitate speciation in representatives of the genus Gasterosteus, so it occurs extremely rarely and occurs due to the fusion of chromosomes (similar chromosomal rearrangements within the species G. aculeatus have not been noted). Thus, at least in this case, the mechanisms of speciation (saltation mechanisms) are completely different from the mechanisms of generation of forms within the species.

In this work, the dynamics of the temperature profile in the soils of Central Siberia were restored and analyzed based on data from weather stations, revealing the patterns of the long-term (1963-2022). The relationship between the temperature regime of soil in the permafrost zone and the long-term dynamics of air temperature during winter and summer was quantified. The current trends in soil temperature regimes along the depth gradient were evaluated in relation to climate changes in the region. An increase in the average annual temperature for each soil layer was typical for all variants of the degree of permafrost closure. The increase in the average annual soil temperature is manifested up to a depth of 320 cm, with a growth coefficient of 0.66-0.70 °C/10 years. Maximum values of the coefficients (0.67-1.64 °C/10 years) are typical for the permafrost zone of the coast of Central Siberia. At the same time, the average annual soil temperature parameters correlate with the dynamics of air temperature. The correlation is most significant for the upper soil horizons (r ~ 0.8) and naturally decreases with the depth of the soil profile. This pattern is most prominent in the coastal zone of continuous permafrost (>75° N). Predictive temperature profiles of soils were obtained with reference to permafrost zoning in Central Siberia. The projection of soil temperature regimes until 2050 indicates the potential for significant modifications in seasonally thawed layers. According to our estimates, the increase in thickness could be between 3-12 cm/10 years.

The ecological and geographical differentiation and dynamics of the autumn migration of passerine birds of the Putorana Plateau are analyzed. In 1988-2004 on an area of 150000 km², 8 points were surveyed in the western and central parts of the region. The route accounting method was used. The passerine fauna of Putorana during the autumn migration period includes 42 species. Birds fly along a narrow coastal-edge strip along the banks of large rivers or lakes in the southern, southwestern or western directions. There are species distributed everywhere ( n = 16; 38 %), locally ( n = 9; 22 %), and locally ( n = 17; 40 %). Bird population density is 239-643, on average ( n = 8) - 440 individuals/km². The population density of passerines during autumn migration is maximum in the south of Putorana, less in the middle part of the region, and minimal in the north of the plateau. At multi-day observation points on the days of the most intense flight, the population density was 420-796, with an average ( n = 2) of 608 individuals/km². Passerines fly at 8.00-12.00. For most species, the average duration of the entire autumn migration is 20-26 days, the main one is 7-12 days. The vast majority of individuals of almost all migratory species are united in monospecific and polyspecific flocks. The configuration of the autumn flight is a combination of four waves with four well-defined maximums. The most powerful surges of migration activity are associated with a decrease in air temperature and the absence of precipitation. The bulk of individuals of different species of the same genus usually migrate on different days. Synchronization of waves of maximum passage is rare in related species. The population is dominated numerically by the Arctic Warbler, the Common Redpoll, and the Little Bunting.

The distribution patterns of plant families along the aridity gradient with regard to their role in the floristic composition and structure of grasslands in Inner Asia were studied. We determined the relationships between the aridity, diversity and activity of 35 leading plant families using Thornthwaite index on the basis of formalized analysis of 6256 relevés. The studied aridity gradient covers most territory of the Eurasia (88 %). Communities were analyzed from subalpine tall-grass meadows in the hyper humid areas of the Altai-Sayan mountains to the deserts of Central Asia. Different results had been obtained when comparing family-species spectra with different levels of aridity considering species composition and importance values (activity). The correlations between the aridity index and 35 families in 16 synoptic species indicated that the ten most rich families Asteraceae, Chenopodiaceae, Fabaceae and Poaceae showed strong positive relationship with aridity index, the family Brassicaceae showed a moderately positive relationship with aridity index, the family Ranunculaceae showed a strong negative relationship with aridity index, and Apiaceae, Caryophyllaceae and Rosaceae had a moderately negative relationship with aridity index. The correlation analysis of the importance values of the 35 families with the aridity index showed that Asteraceae, Fabaceae and Poaceae were not associated with the aridity gradient, suggesting their significant ecological and phytocoenotic heterogeneity. Among other top families Chenopodiaceae and Brassicaceae had strong positive relationships with aridity - Caryophyllaceae, Lamiaceae and Ranunculaceae had strong negative relationship with aridity and moderately negative relation - Apiaceae and Rosaceae. The use of species constancy and abundance in taxonomic spectra analysis can take into account the phytocoenotic importance of plants. This approach can be used to search for indicators of climatic processes, including those related to aridification of Inner Asia.

The influence of catastrophic forest fires on the ground cover in the forests of the Lena-Vilyui interfluve has been studied. Obtained results showed changes in species diversity, and reserves of aboveground phytomass of the ground cover in the larch and pine forests in natural and in burnt state. The correspondence analysis species composition on the control and the burnt sites showed that the control pine and burnt forests have similar distributions, and the control larch and burnt forest differ in the distribution of species. Compared with 2022, in 2023, the burning of larch and pine forests showed an increase in aboveground phytomass by 1.6 and 4.4 times, respectively.

The aim of this work was to study the bioproductivity, C-biomass and elemental composition of humic acids as a single ecosystem of dry-steppe soils. The objects of the study were virgin chestnut soils of the southern steppes of Western Transbaikalia. It was revealed that chestnut soils are formed under dry-steppe plant associations with sparse and low-growing grass, with a poor species composition. The net primary production in chestnut soils of the study region is 4.80 ± 3.48 kg/m² year, where the underground mass exceeds the aboveground mass by 9 times. Plants of more continental steppes, with a greater moisture deficit, direct a larger proportion of photosynthetates (up to 90 %) to the root mass compared to plants of the western steppes. The ratio of BNP to ANP is 1 : 9 and can reach 1 : 25. The participation of C-biomass of microorganisms in the total reserve of organic carbon of chestnut soils is up to 2.5 % of Corg. The dynamics of accumulation of C-biomass is limited by soil moisture and the reserve of energy resources. The elemental composition of HA of cold, chestnut soils is characterized by a low carbon content; relatively high content of nitrogen and hydrogen. The molecule of HA of chestnut soils has a weakly condensed aromatic nature, the aliphatic part predominates in it. The consequence of the weakened condensation reaction is an insignificant level of the degree of benzenoidity. ¹³C-NMR spectroscopy showed that the humic substances of chestnut soils are characterized by a reduced content of aromatic components.

Climate warming leads to a wider distribution of heather shrubs, with biochemically very active ericoid mycorrhiza, in mountain meadows of temperate latitudes, where less active arbuscular mycorrhiza predominates. Our working hypothesis was: the expansion of heathers can increase the microbiological activity of soils (basal respiration, respiratory metabolic coefficient, activity of hydrolytic enzymes, rates of nitrification and ammonification), specifically change the taxonomic composition of the prokaryotic complex, nitrogen, carbon and phosphorus status of soils. These indicators were compared in different relief elements in the humus-accumulative horizons of Umbric Leptosol under shrubs and grasses in regions contrasting in climate and soil-forming rocks: the alpine wastelands of the North-Western Caucasus and the mountain tundra meadows of the Khibiny. The same heather species grow in these regions, which makes it possible to isolate the direct specific influence of plants, regardless of other environmental factors. The specific effect of the presence of heathers has not been established. The soil properties were primarily influenced by the location of sampling (position in the relief, soil-forming rock). The second is the region of study (climate). The features of the prokaryotic complex specific to each sampling site are not interrelated with the studied chemical parameters and microbiological activity. Nevertheless, general differences in the prokaryotic complex are associated with pH_Н2O, indicators of carbon (C_SOM), phosphorus (P_{ext. min}, C/P_SOM) and nitrogen (N_micr, C_SOM/N_ext, N-NH₄⁺) state of soils.

Impending climate and environmental changes will require robust species distribution modeling to inform management decisions to mitigate their impacts on biodiversity. Such modeling needs the appropriate data (often including many variables) that have influenced species’ distributions over time. The Daurian Pika is a good model species for climate warming feedbacks because of its habitats climate extremes (very hot summers, very cold winters) and its key role in ecosystems of the northern Asian steppes. In this study, we quantified the predictors of pika abundance at a local scale. In 236 plots (10 × 10 m²), we measured 8 environmental variables and counted the openings of pika burrows as an index of the relative pika abundance. Generalized linear models were used to identify the dependence of the openings number on chosen environmental predictors. In the independent field study, we counted the number of pika burrow openings in the plots of the same size and used it to test the best models. The best models include percentage coverage of dense tall vegetation, slope aspect, and soil thickness as predictors. Pikas are more abundant in the plots with thick soil covered by dense, tall vegetation. Also, there are trends to set burrows on gentle slopes and plains, on grounds with slightly dense or dense and plastic soil, with low stoniness. The number of burrow openings is significantly lower on the northern and eastern slopes. Our best model predicted number of burrow openings in test plots in two localities reasonably well. Our results demonstrate that a set of abiotic factors accurately predicts the Daurian pika distribution at a local scale. We suppose that among analyzed factors, some directly relate to pikas and possibly affect their distribution in a similar way in any environment. These are soil characteristics that allow pikas to construct burrows and likely vegetation cover. Other factors mediate the impact of climate on microclimate and food resources, and their effects vary depending on local environment characteristics.

Our study is devoted to foraging strategies of sympatrically nesting Glaucous Gulls (Larus hyperboreus) and Vega Gulls (Larus vegae) in two locations on the Chaunskaya Bay of the East Siberian Sea. Both species of gulls nested both in colonies and single pairs, and their foraging methods were similar: scavenging, collecting, and active predation on eggs and chicks. Anthropogenic food sources were prioritized by both species. The second most important food source for Glaucous Gulls was birds, whereas for Vega Gulls it was isopods. Differences in diet between gulls breeding in colonies vs gulls breeding as single pairs were more substantial than differences in food spectrum between different species with the same nesting strategy. This pattern is especially prominent in with Vega Gulls. Single pairs of both species could not afford long foraging trips and foraged in the cloth vicinity of their nests, using other bird species as a prey (a stable available resource in the nesting habitat). Colonial gulls foraged mostly on landfills (a stable resource but located far away from the nesting sites).

The anthropogenic impact on various components of aquatic ecosystems and, in particular, on the structure of river zooplankton communities requires comprehensive study in modern conditions of intensive environmental natural resource management. The aim of our study was to assess the impact of urban wastewaters on the chemical composition of water and structural parameters of river zooplankton of the River Stepnoy Zay, a small river from the industrial zone of the Middle Volga region, a left tributary of the Kama River. Sampling was carried out from 2008 to 2019 upstream and downstream of municipal wastewater discharges of the four cities located in the upper, middle and lower reaches of the river. Our results showed that the main chemical compounds that significantly differed in their concentrations in the areas above and below urban drains were ammonium, nitrates, phosphates, organic substances (BOD₅). These pollutants were also the most significant variables explaining variations in the species composition and quantitative indicators of zooplankton. In relation to the leading environmental factors, 3 groups of species were distinguished: indicators of organic pollution; species tolerating increased mineralization; species sensitive to oxygen content. 114 zooplankton taxa were identified in the river. The abundance and biomass of zooplankton varied significantly at stations above and below cities. Zooplankton communities below cities in the upper and middle reaches of the river (Bugulma, Leninogorsk, Almetyevsk) are influenced by the influx of planktonic organisms from biological treatment facilities with wastewaters. The stations in the lower reaches of the river belong to the mouth section and zooplankton communities here are formed under the influence of the river Kama. Observations of the development of zooplankton communities will continue.

The methodology to determine physical and mechanical properties of granular materials containing coal is substantiated. A set of methods and facilities is developed to find bulk density, cohesion coefficient, internal and external friction coefficients and distributive capacity for ROM coals, coal concentrates and other coal-bearing materials. The laws of change in the listed characteristics within some variation intervals of process parameters are found for the real-life processes of coal flow and storage. The integrated studies and systematization of coal flow process parameters are described.

Selection of efficient methods and means for rock fracture is one of the major challenges the coal mining industry is faced with. For rocks of high hardness, the most efficient fracture method is drilling with button bits. The main objective of the implemented research is determining the actual time of contact between bit buttons and rock and the required time of contact to reach the destructive load with respect to various influences.

The authors analyze the mechanical and process properties of gabbro, diorite, peridotite, serpentine and talc carbonate rocks of the Bazhenov chrysotile asbestos deposit. The hardness metering is performed on the surface of the sampled hand specimens. Their compression and tension strengths are found in the air-dry condition. The interrelations are revealed between the mechanical properties of the test rocks and the hardness meter readings. Using an empirical relationship, the crushability classes of the test rocks are determined. The correlation is found between the hardness meter readings and rock crushability at the test deposit. Finally, it is inferred that the present-day idea of the rock strength-crushability connection is valid both in traditional and express method testing.

Experiments on dried and saturated marble samples were conducted at different loading rates to investigate the influences of loading rate and saturated water on the deformation, strength and brittleness indexes of marble. Strength and deformation, the applicability and variation of different brittleness indexes, and the relationship between elastic strain energy limit and brittleness indexes were analyzed comprehensively under different loading rates. The results show that the strength of marble increases with an increase in loading rate, while elastic modulus decreases and peak strain increases. The influence of loading rate on brittleness was analyzed for seven values of the latter. The results indicate that some of the indexes of brittleness cannot reflect the influence of loading rate. Meanwhile, there are two indexes that can accurately express the variation law of rock brittleness with an increase in loading rate. Moreover, these brittleness indexes increase linearly with an increase in loading rate and exhibit a quadratic function relationship with elastic strain energy limit. A new brittleness index that can comprehensively consider strength and energy is proposed to fully express the effects of loading rate and saturation on rock brittleness. In accordance with the macroscopic failure characteristics of marble, the conclusion that a brittleness index increases with an increase in loading rate was proven correct.

The article addresses peculiarities of solid mineral mining in difficult geological and hydrogeological conditions in eastern Russia. The known methods of preparing wet deposits for their further mining are reviewed. Special attention is given to mineral extraction from deposits in river channels, which is the most expensive process subjected to difficult-to-accomplish ecological requirements. The wet deposits are grouped with respect to possible drainage and opencast mining technologies. Some eco-oriented mining technologies are put forward, with efficient management of natural and manmade resources.

A correlation is found between the pressure pulse amplitude of the power unit of a vibration exciter and the impact energy of the driving piston of an electromagnetic percussion drive as a component of the exciter. The correlation is used to investigate energy characteristics of the electromagnetic drive. It is shown that the energy contributed by the flyback coil to the total mechanical work done by the electromagnetic drive in one cycle is 70-75%, while the energy contributed by the forward run coil is 25-30%.

The authors present a practical problem solving scheme for the prediction and control of mining machine condition using real data from sensors tracking basic parameters of open pit mine trucks. The network analysis of signals from 15 sensors is performed for two systems of Komatsu HD1500-8 dump truck: internal combustion engine and gear shift transmission. The network nodes are selected to be the time series data on one operation shift of the machine. Connections between the time series were found on the basis of similarity of temporal sequences. The similarity between temporal sequences was estimated using the Dynamic Time Warping (DTW). The networks were constructed using a threshold model, with a threshold set as the time-series similarity. It is found that some networks respond to a machine failure on the day of its occasion, the day before and the day after it. The results prove applicability of the network analysis for the timely detection of mining machine failures.

The article focuses on the upward potential of efficiency in vibropercussion driving of steel structural tubing shapes in soil by means of improvement of interaction between the components of the air-driven hammer-pipe-soil system. The preproduction model of a generator with the stepped adjustment of the movement intensity of the traveler member via transition to the increased pressure of an energy source is described. The experimental modeling data on penetration process are reported as function of loading of a pipe string by the equipment with different kinetic parameters-mass and piston-anvil co-impact velocity. It is determined how these parameters influence amplitudes of generated power pulses and the resultant advance of a pipe per unit impact in the elastoplastic soil mass.

The article describes the observation data on temperature at a place of spontaneous combustion at a waste dumps via holes drilled to a depth of 2.5 m. The 4 years-long measurements made it possible to determine the temperature change patterns in coal-bearing waste in the surface layer, as well as at the depths of 0.5, 1.5 and 2.5 m depending on seasonal variations in air temperature. The temperature grows with depths in all holes. For this reason, at the hole length of 2.5 m, the efforts to size the source of spontaneous combustion depthward the waste dump failed. Within the observation period, the maximal temperature of rocks at the source was 500 °С.

The authors analyze the influence exerted by content of common salt in pore space in frozen ground on moisture migration processes. The scope of the analysis encompasses three types of ground (clay, chalk and clayey sand) typical of freezing depth in shaft sinking at potash mines. It is found that the increase in salinity decreases intensity of frost heaving, except for a zone of small concentrations (to 0.0035 kg of salt per 1 kg of dry mineral). The total mass of salt transported to the freezing front grows nonlinearly with the increase in the initial salinity. The obtained results are theoretically interpreted using Darcy’s law for moisture migration rate, and the convective diffusion equation for salinity. It is shown that the key parameter to define the non-monotonous behavior of moisture migration toward the freeze front is the relative hydraulic permeability of ground, which in a complex manner depends on salinity.

The mechanism of change in the acid-base properties of quartz and the structural changes of magnetite surface under the action of low-temperature air-dielectric barrier discharge plasma were experimentally investigated under standard conditions with a view to enhancing extraction of quarts in froth product of reverse cation flotation, and to refining quality of magnetite concentrate. Improvement of electron-donor properties of quartz surface governed the increased adsorption and flotation activity of the mineral relative to cation reagents. The effective parameters of diffuse barrier discharge and the time of plasma pretreatment of mineral samples are determined. As a result, the recovery of quartz in froth product grew by 8-10% and the yield of magnetite was no more than 5%. The modifying effect of the low-temperature atmospheric-air plasma improved the quality of magnetite concentrate at Mikhailovsky GOK from 68.91 to 70.34% owing to the increased recovery of quartz in the froth product of reverse flotation by 3.20%.

The article describes the research aimed at improvement of pretreatment and processing technologies as a case-study of refractory complex ore with regard to specifics of its mineral composition. The ore features a fine-grained structure, with numerous micro-interpositions and close intergrowth of ore minerals. Crystals of sphalerite, which is the main mineral of the test ore, has emulsion-type dissemination of chalcopyrite and other sulphides: galena, pyrite. The use of X-ray radiometric separation as a method of ore pretreatment is investigated.

Separation facilities ensuring flexible control over produced ore mass quality, with potential production of concentrates with high metal content are examined. The process solutions are justified to develop small gold ore deposits located far from processing factories, in the areas of the underdeveloped or missing energy infrastructure. A mobile processing facility carries out two-stage X-ray radiometric separation of sorted ore classes, with production of tailings, middlings and concentrate via float-and-sink separation. Middlings are treated on-the-spot by heap and trench leaching, and concentrate is shipped to a long-distance processing factory. Separate processing of different-grade mineral raw material enables high metal recovery at a reasonable cost.

In order to separate fine-grained monazite minerals from other heavy minerals and silicate gangue minerals, this article discusses flotation studies carried out at various flotation process parameters, such as reagent doses, pulp pH, conditioning time and flotation time. Surface response techniques and experiments were used in optimization research. The best flotation performance conditions are determined to be as follows: pulp pH-9, pulp density-30%, depressant sodium silicate-1.2 kg/t, collector oleic acid-1.2 kg/t, conditioning time-5 min and flotation time-10 min. A single stage yields a monazite grade of 94.8% and a recovery of 95.3% from a feed comprising 52.3% monazite, based on the experimental parameters mentioned above and the expected values determined via response surface methods. Cerium monazite, which is appropriate for recovering rare earth elements, is present in this sample.

Quartz raw materials for the foundry and glass industries, which must have an appropriate satisfying chemical and particle size composition, according to the standards and special requirements of users, are produced at quartz sand separation plant in Serbia. The process of quartz sands preparation in a separation plant is simple and includes the following stages: screening, washing, classification and attrition. In practice, depending on market requirements, different types of sand from different deposits are processed. In addition, the sands in the deposits are heterogeneous and differ, most often, in the content of clay to be separated, so in many cases it is difficult to satisfy the requirements of consumers. One of the reasons is the lack of automatization, where changes in process flowsheet lead to a stop of process, which entails difficulties in operation and stoppage of this process unit. Taking in the account the above, in order to implement optimal automated control and monitoring of the process, industrial tests were carried out on a separation plant. The tests were carried out on a hydrocyclone of the first stage of classification (as the most important unit of this process), equipped with appropriate control and measuring devices (CMD) to perform this task, namely: a frequency regulator of the pump electric motor and a manometer for measuring the pressure at the feed inlet of the hydrocyclone. In order to evaluate the classification process of various quartz sands in a hydrocyclone, the classification efficiency was determined using partition numbers and a partition curve, and taking into account the parameters of the sharpness of separation. The obtained results of industrial tests have confirmed that as a result of changing the feed pressures of the hydrocyclone, while controlling other technological parameters of the process, it is possible to successfully treat raw quartz sands from various deposits and obtain a product with satisfactory characteristics, especially in regard to particle size distribution. In addition, the results are encouraging in relation to future implementation of automatic process control and appropriate monitoring.

This study aims to assess and predict blast-induced ground vibrations of opencast coal mine. The analysis was carried out using two methods i.e. the widely employed empirical vibration predictor known as the USBM (United States Bureau of Mines) equation, and a machine learning model called the artificial neural network (ANN). A dataset including 38 blast vibration recordings was collected and used for the development of an ANN model. Additionally, these datasets were employed to evaluate the site determination constants of the empirical vibration predictor. A total of 27 recordings of blast-induced ground vibrations were gathered from the same opencast coal mine in order to assess the effectiveness of both models. The output (dependent variable) for both models is the peak particle velocity. The effectiveness of the prediction model was evaluated by using commonly used statistical measures, namely the coefficient of determination (R²). Consequently, the ANN model that was built exhibited more precision in comparison to the existing empirical model. The ANN model exhibited a strong positive relationship between the observed and anticipated peak particle velocity values, as shown by the coefficient of determination (R² = 0.84).

Climate warming in recent decades has had a strong impact on tree populations, which will either adapt to new conditions or their mortality rate increases. The results of provenance tests can serve as a reliable basis for studying the response of trees to environmental change. Since the early 1990s, modeling of phenotypic traits of populations from climatic factors (seed origin and testing sites) and the use of such models in forestry practice have been developed in foreign countries. The objective of this review is to consider the main approaches to modeling tree responses to climate change based on provenance test data and discuss their application to climate-smart forestry. Individual transfer and reaction functions and more complex models (generalized transfer function and universal transfer and reaction functions) are useful tools for solving problems related to forecasting the response of tree populations (growth, productivity and survival) to climate change and assessing their adaptive potential, developing recommendations for seed transfer (including assisted migration) and climate-smart forest seed zoning, safing and increasing the resource and ecological potential of future forests. The results of historical and current provenance tests in conditions of rapid climate warming have special scientific and practical value. The development of reliable models for forecasting the response of forest-forming tree species populations to changing environmental conditions is possible in the presence of representative data on their phenotypic variability. This requires the formation of databases combining the results of provenance tests data.

The competition of trees for light, moisture and nutrients is usually considered as the main factor of interaction between trees, but this idea is questioned by examples of cooperation or cooperation through natural root grafting. In connection with the discussion of the phenomenon of plant root grafting, the most important question in biology about the relationship between individual species and individuals within a species has been developed. The importance of root grafting lies in its ability to influence the physiology and ecology of grafted trees, however, the processes contributing to the formation of root grafting, the factors involved and their effects are unknown. The question of whether the root grafting is accidental or a natural phenomenon is still controversial. The effect of live stumps on a growing tree remains uncertain. It is known that root grafting provides increased mechanical stability of trees in their resistance to wind and is associated with factors such as variability in root morphology, soil structure and moisture, as well as the degree of mutual root overlap. The frequency of root grafting increases both with the age of the stand and with its density. Pathogens, minerals, carbohydrates, hormones, herbicides, microorganisms and water flow through root grafting, but these processes actually have no quantitative basis. Modeling of water flows between grafted trees in mangrove forests at the quantitative level showed that there is no water exchange between trees of the same size or there is an insignificant amount; water movement occurs from the dominant tree to the oppressed one; water movement occurs from a tree growing in humid conditions to a tree growing in non-scarce conditions, and the amount of water received, compared to its own consumption, it is higher if the partner tree is larger. A quantitative approach to assessing the biological and ecological role of root grafting lays the foundation for understanding their impact on the formation and productivity of a stand.

Hundreds of forest fires are registered annually in Krasnoyarsk Krai. From the analysis of statistical data it follows that the main cause of fires are the population, their activities and life support. The greatest anthropogenic fire hazard is observed in the Central Siberian subtaiga-forest-steppe region. In order to assess the anthropogenic fire hazard of the forests of this forest region, studies were conducted that allowed us to identify the causes of forest fires and the main areas of their occurrence in this territory. Zoning of the forest territory of the Central Siberian subtaiga-forest-steppe region by the degree of anthropogenic fire hazard was developed, taking into account the risks of anthropogenic fire hazard in forestry’s. Regionalization of the forest territory by the degree of anthropogenic fire hazard will be useful in planning a set of preventive fire prevention measures and will help reduce the possibility of forest fires.

Possible causes of damage to pine stands in Krasnoturansky Bor in 2022 were studied. Remote sensing data and indicators characterizing the current state of trees were used for the analysis. NDVI values of different forest areas were considered and the moment and intensity of tree damage were estimated based on these indicators. The spatial distribution of trees by the level of damage along the selected transect was studied and it was shown that the level of damage decreases linearly with increasing distance to the forest edge. Based on the results obtained, it is assumed that the cause of the damage could be a chemical burn of trees caused by herbicides when treating agricultural land near the forest edge to destroy weeds. The patterns of change in the current state of trees after impacts were studied depending on their state before damage and the state of trees before the impact on the crowns. To assess the current and retrospective states of trees, a set of indicators is proposed, including the characteristics of the spectra of the first differences in the widths of annual rings of trees in the damage zone 2-20 years before the date of damage, dielectric indicators of tree tissues, and response functions of remote characteristics of stands. It is shown that with the same visual state of trees before and after damage, their response to the impact differs significantly and some of the trees of condition category 1 according to visual features should be classified as trees with a certain level of weakening as a result of the impact. The use of a set of methods made it possible to assess the response of trees to the impact depending on their initial state before the impact.

The results of a study of the impact of current climate change on the dynamics of turanga (syn. Euphrates poplar), Populus diversifolia Schrenk) radial growth of trees in tugai forests (a form of riparian forest of semi-arid area) of Kazakhstan are presented. The studies were carried out in the study sites (SS) within the floodplains of the Ili river and the Syrdarya river. It has been revealed that since the beginning of intensive warming and aridization of the climate since the late 1990s, the radial increment of Turanga growing in the SS “Ili” has decreased 4-fold, while in the SS “Syrdarya” - 2.5-fold. Climate correlation response functions revealed that climate change since the late 1990s modified reaction of the trees to climate factors in the SS “Ili”. This was expressed in the appearance of their negative reaction to increased April-July air temperatures and a positive reaction to increased June precipitation. Current climate change has not affected the climatic response of trees in the SS “Syrdarya”. Thus, it is shown by dendrochronological study of Turanga that in some cases the response of woody species to climate warming could be offset by other, factors, for example, deficit of available soil moisture and anthropogenic impact. It is assumed that the radial increment values of Turanga trees can be used in the studies of the influence of various hydrological regimes of rivers on tugai forests productivity.

Based on the analysis of long-term forest planning materials of the belt pine forests and a reconstructive survey of the state of pine forests of the Aleus forest massif, which underwent selective cutting, it was established that over 80 years of their use, due to a decrease in the density of tree stands, a significant disorder of the forest cover occurred, and the productivity of pine stands significantly decreased. At the same time, mature and overmature uneven-aged pine stands of medium and low productivity began to significantly dominate in pine forests, which reduced the resistance of the forest cover to the impact of exogenous natural and anthropogenic factors, in particular fires. It is predicted that as a result of such a rate of transformation of the age structure of the pine forest, autonomously existing young stands, middle-aged, maturing pine stands will disappear in the next 80 years. Following this, due to the accumulated forest litter and developed grass and shrub cover, forest fires will increasingly occur, which will activate the forest formation process, worked out by nature over millions of years of the existence of the light coniferous species - pine. To eliminate these undesirable consequences, it is recommended to replace selective cutting with classic narrow-clear-cutting.