Home – Home – Jornals – Russian Geology and Geophysics 2023 number 5

We performed a petrochemical study and determined the Sm-Nd isotope composition of the Sumian (early Paleoproterozoic) mafic metavolcanic rocks in the Vodlozero domain (Semch’, Kumsa, and Kamennye Ozera structures) and the Central Karelian domain (Lake Vottomuks and Lake Kogu structures, the western flank of the Lekhta structure) of the Karelian province of the Fennoscandian Shield and compared them with the coeval volcanic rocks of the Kola-Norwegian province and the intrusive rocks of the Karelian and Belomorian provinces. The Sumian mafic rocks intruding the rocks of the Archean domains with different crust ages (>3.1 and 2.7-2.8 Ga) have similar geochemical characteristics (SiO₂ = 44-55 wt.%, MgO = 5-14 wt.%; LREE enrichment, (La/Yb)_N = 5-17) and similar values of ε_Nd( T ) (from -2.7 to -0.5) and T_Nd(DM) (from 3.0 to 2.7 Ga), which distinguishes them from their Archean analogues and indicates a single large magma source. The crustal contamination of the primary melts did not exceed 15% and could not determine the isotope-geochemical specifics of the Sumian mafic rocks. Their specific composition is better explained by the model of the formation of primary melts through the low-pressure (2.5-3.0 GPa) melting of the Neoarchean metasomatized zones of the subcontinental lithospheric mantle, with the addition of the primitive-mantle melts. In the period 2.41-2.45 Ga, the early Paleoproterozoic mafic rocks of the Fennoscandian Shield formed in the intracontinental magma generation setting.

The Novaya Zemlya archipelago is an early Cimmerian folded structure located on the northern periphery of the Ural-Mongolian Fold Belt. The geological development of the archipelago is well-studied and serves as a benchmark for interpolating its features to the shelf of the surrounding water areas, whose sedimentary cover contains large accumulations of hydrocarbon raw materials. In addition to the stratified section of essentially sedimentary strata, it is of interest to study igneous formations that clearly mark tectonic events in the geological history of the archipelago. In the light of the latter, the age of these formations remains important. The age of some magmatic complexes of the archipelago remains debatable. This paper touches upon a lamprophyre complex in the extreme south of Novaya Zemlya, which until recently has been dated to the late Proterozoic or late Proterozoic-early Paleozoic (?). The results obtained for the U-Pb age of apatites contained in the rocks of this complex confirm the Devonian age of lamprophyres, and it is suggested by estimates based on the presented data that the emplacement time lies in a range from 360 to 398 Ma. This means that they can be associated with riftogenic processes on Novaya Zemlya since the second half of the Early Devonian, when the stage of short-term stable carbonate sedimentation (in the first half of the Devonian period) was replaced by the initiation of a new structural-formational zonal sequence.

We report results of a detailed study of the paleomagnetic record in the sedimentary rocks of the Taseeva Group of the Yenisei Ridge in three typical sections in the lower courses of the Angara, Taseeva and Irkineeva rivers. Our results confirm that the geomagnetic field was in an anomalous state at the Precambrian-Phanerozoic boundary. It is well known that Ediacaran rocks in general have preserved several different paleomagnetic directions that do not conform to the geocentric axial dipole model. For example, Siberian sections display two equally valid groups of paleopoles that cause many debates over the geometry of the geomagnetic field and whether any of the components correspond to its dipole configuration. The paleomagnetic record we studied is unique in that the rocks of the Chistyakovka and Moshakovka formations have captured both these components, which is factual evidence of a synchronous existence of two sources. To explain these findings, we propose an original hypothesis in which the bipolar component that is widely present in the rocks and corresponds to the Madagascar group of paleomagnetic poles is associated to the field of the geocentric axial dipole. The less widespread monopolar component corresponding to the Australian-Antarctic group of poles is reflective of a stationary anomalous source. The recording of this source became possible due to the abrupt decrease in the strength of the virtual dipole moment that probably was at its lowest during the accumulation of the Chistyakovka and Moshakovka formations. The new paleomagnetic pole calculated for the bipolar component - 39.2°N, 61.1°E - plots on the apparent polar wander path for Siberia and can be considered a key determination for the age ~570 Ma.

The role of additional channels for the decay of an excited level on the formation of coherent states of the ground level in alkali metal atoms upon interaction with polarized radiation is studied theoretically. Using an example of ³⁹K, calculations show that these coherent states cannot be completely destroyed due to using additional decay channels.

A new method for estimating the bulk diffusion length L_dif of photogenerated charge carriers in the absorber material of mercury-cadmium-tellurium-based infrared focal plane arrays (MCT-based IR FPAs) is proposed. The method is based on the analysis of the modulation transfer function (MTF) of IR FPA detectors in normal operation and in operation with reduced gate voltage of input pixel field-effect transistors, when the built-in junction barriers of FPA diodes turn out to be reduced, and multiple re-emission of mutually induced microscopic currents of neighbor photodiodes takes place. The proposed mathematical model for the MTF of MCT-based FPAs assuming the capture of emitted electrons by the nearest FPA pixels provides an adequate description to the experimentally observed behavior of the diode-array MTF during the transition of FPA to the latter operation mode. This fact is illustrated in the article with the example of a 30-μm pitch FPA with ~10×10-μm diode sizes and 6-μm absorber-layer thickness. The coefficient of transfer of the injection current of a forward-biased photodiode to an adjacent pixel, which appears in the model, depends on the geometrical parameters of the diode array and on the length L_dif , and it can be used for determining this length.

The results of a study of remote temperature measurement systems of industrial electrical installations based on bolometric photodetector cameras are presented. A photodetector thermal imager camera of the FLIR system and a specialized radiometric thermal imager with internal temperature sensors and calibration shutters are considered. The best coating for calibration shutters with a minimum level of reflection of IR radiation from their surface has been determined (the integral reflection coefficient in the spectral range of 8-14 microns is no more than 5.8%). A mathematical description of the calibration process of the thermal imager camera of the FLIR system in a wide range of temperature changes of its components and the ambient medium is given. The requirements to the thermal imager camera for remote temperature diagnostics systems of industrial installations are analyzed.

In the study, the first data on the distribution of cyanobacterial toxins were obtained and, for the first time, a molecular genetic determination of cyanotoxin producers in the plankton of some lakes in the permafrost zone in Yakutia was carried out. Most of the lakes were characterized by high concentrations of nitrogen, phosphorus, chlorophyll a and an increased content of organic matter, which could be associated with a high anthropogenic load. During the summer period, water blooms were visually observed in three of the six studied lakes. The abundance and biomass of cyanobacteria in the lakes varied within 13.7-676.3 million cells/l and 0.6-4.8 mg/l, respectively. Eight species of potentially toxigenic cyanobacteria were found in phytoplankton using light microscopy. In environmental DNA isolated from planktonic samples, regions of the mcyE gene involved in the biosynthesis of microcystin were amplified using the polymerase chain reaction method. During the study period, cyanobacteria capable of producing neurotoxic anatoxin-a, saxitoxins, and hepatotoxic nodularins were absent in the lakes. Using genus-specific primers to the mcyE gene, it was found that species of the genus Microcystis were the main producers of microcystins in most of the lakes; and species of Dolichospermum - only in one of the lakes. Up to 8 structural variants of microcystins, in general arginine-containing isoforms MC-LR, MC-RR, MC-YR, MC-LY, MC-HIlR, [Asp³]MC-LR, [Asp³]MC-RR, [Asp³]MC-YR, were identified in lake plankton using liquid chromatography-mass spectrometry. The maximum concentration of microcystins in plankton (intracellular fraction, 803 ng/l) was recorded in a sample from Lake Ytyk-Kel. The calculated content of microcystins per unit biomass of producing cyanobacteria (toxin quota) was low (0.005-0.069 µg/mg). In order to assess the potential hazard of toxigenic species of cyanobacteria to human health, the distribution of cyanotoxins and their producers should be further studied in water bodies of the region.

For the first time the diatom complexes were investigated in the upper part of bottom sediments in the freshwater lakes Cheko and Zapovednoye, located in the taiga zone of the south of Evenkia on the territory of the Tungussky state reserve. There were found and identified 156 diatom taxa in two lakes, and their ecological preferences have been determinate. In the Lake Cheko the valves of Aneumastus tusculus (Ehrenberg) D. G. Mann & A. J. Stickle was identified - this diatom officially described as a fossil. In the both lakes the similarities and differences in the diatom complexes have been revealed - it seems that the diatom complex of both lakes is similar to that for freshwater bodies of the world located at close latitudes in the taiga zone. Lake Cheko is distinguished by a smaller proportion of planktonic species, which is probably due to the greater flow of this lake. Also there is shown the dependence of the species composition of diatoms on the meteorological parameters of the environment (temperature and precipitation).

The article presents an estimate of methane emission in palsa mire in the European North-East of Russia based on the results of measurements by the method of static chambers and eddy covariance during the growing season. Hollows make the main contribution to the ecosystem flux, the rate of methane emission per season on these relief elements averaged 5,7 mg/(m²∙h) and was controlled by soil temperature and groundwater level. The methane emission on the ridges and the peat mound was noticeably lower and corresponded to 0,85 and 0,28 mg/(m²∙h). On the peat mound, the methane flux depended on the thickness, temperature, and humidity of the active peat layer. The cumulative ecosystem flux of methane into the atmosphere in May-September, obtained by the method of chambers and eddy covariance, corresponded to 9,5 and 11,4 g/m².

А 36-year study of bird number dynamics (1984-2020) on permanent accounting routes from the coast of Lake Baikal to the Barguzin Range highlands (460-1700 m s. l.) were performed. A steady decrease in the total abundance of background bird species after 1997-1998 was revealed. The resulting long-term series (as the example of model groups of birds) made it possible to identify the responses of the biota on climatic changes in the Lake Baikal region. Periods of high and low numbers in bird`s populations are probably associated with the passage of a wet and arid phases of a climatic cycle. In 8 background species (16.0 %), positive trends of long-term changes in abundance were revealed, and in 18 species (36.0 %), a steady decrease in abundance was established. Negative trends in population changes in distant migrants prevail over growth trends (11 species against 3 with positive trends). Some mechanisms of the formation of the local bird`s population are disclosed, including using the redistribution of the nesting species density between the river valleys and habitats at the high-altitude profile. Current long-term climate change in the region has a positive impact on changes in the abundance of background bird species in the highlands compared to the underlying mountain forest belt.

After results of autumn counts of waterfowl in the Selenga delta in 2018-2020, their recent numbers during the autumn migration were estimated, and its comparison to results of analogous intensive censuses in 1989-1995 was carried out. The decreasing of numbers and percentages was found in some duck species (Northern Pintail, Eurasian Wigeon, Northern Shoveler, and Pochard); these parameters are rather stable in Mallard. Data on stopover longevity obtained in other regions of the world in the last time let us to give more precise retrospective estimates for numbers of waterfowl having visited the Selenga delta during autumn migrations in the 2nd half of 1980s and the 1st half of 1990s. More adequate numbers of stopping birds in the period mentioned above are 0.5-1.1 million individuals per season (at least, not less) instead 2-5 million being proposed formerly. In the present time, the lower number limit for ducks having visited the delta per autumn season obviously appears to be 0.3 million individuals; intensive counts during all autumn migration are necessary to set the upper limit. Numbers of waterfowl are approximately twice less now than 30-35 years ago. Causes of their decrease need to be sought outside the Selenga delta, probably in the general situation in regional and trans-regional geographical populations. The delta prolongs to support more than 1 % of the East Asian geographical population of Pochard, which recently got the status “Vulnerable” in the IUCN Red List. The nature refuge “Kabansky” plays the much important role as the no-take zone for waterbirds during autumn hunting seasons.

The Neuroptera of the pine Tanaika Forest in the Republic of Tatarstan were studied using five beer-and-sugar bait crown traps operated continuously from 30 April to 1 October, 2021. The chrysopids Apertochrysa prasina and Chrysotropia ciliata clearly dominate among 1043 collected specimens (17 species). The number of species stenotopic for pines (Chrysopa dorsalis and Wesmaelius concinnus) is very low. The large number of Chrysopidae in this forest, normally characteristic of a deciduous forest, and the rarity of species characteristic of pines, can be explained by the fact that the traps mainly attract Neuroptera that feed at imaginal stage on pollen and honeydews, whereas almost all species characteristic of pines are predators. In addition, the traps on pine trees were located at a relatively low height (4-5 m from the ground), and so they attracted more specimens from the nearest deciduous trees and deciduous undergrowth than from pines, whose canopies are located much higher. Eleven species of Neuroptera are recorded from the Republic of Tatarstan for the first time; thirty-two species are now known from the region.

The rhythm of development, seasonal dynamics of photosynthetic pigment content, specific leaf area (SLA), water content, and the rate of accumulation of dry matter in D. octopetala leaves of spring and autumn generations under introduction conditions were studied. The obtained results were compared with similar indicators in the natural habitat according to the literature data. It was found that the restructuring at the cellular-tissue level led to an increase in the specific leaf area by 3.7-4 times. The leaves of the spring generation have increased the life span, the duration of vegetation, the amount of chlorophylls and carotenoids. In the leaves of the autumn generation, these indicators have not changed. The leaves of the spring and autumn generations contained 7.89 mg∙g^-1 and 3.32-6.48 mg∙g^-1 of chlorophyll, respectively. The structural and functional characteristics of the pigment apparatus of the leaves of spring generation corresponded to the high intensity of photosynthesis, the autumn - low intensity. Under the conditions of introduction, the former showed ecological plasticity and a high ability to acclimation changes, the latter - a conservative, stenobiont adaptation strategy. The growth rates of D. octopetala remained at the characteristic level for the species. The number and mass of diaspores per flower, the length of peduncles increased by 2.2 and 2.8 times, respectively. Germination over the entire observation period was low, 2.32 ± 0.7 % over a six-year observation period.

Changes in the seasonal development of lilac species in the collection of the South Ural Botanical Garden-Institute (Ufa, Russia) are analyzed according to data for 2005-2010 and 2015-2020. The objects of research were 11 species of lilacs that have reached the generative phase; all types of lilacs are grown from seeds obtained from other botanical gardens in the 50-60s. last century. Phenological observations of lilac species are carried out annually in 9 phenological phases. The onset of the initial (opening of the buds and the beginning of the growth of shoots) and the final (leaf fall) phases of the growing season largely depends on the weather conditions of a particular year. At the same time, the role of species (genetic) features at the beginning of seasonal development is insignificant (species begin to vegetate together), while, starting from the flowering phenophase until the end of the growing season, this role increases significantly. The significance of interannual differences in the middle of the growing season fades into the background. Such characteristics of development phenorhythms as the duration of flowering and the duration of the growing season continue to be dependent on fluctuations in weather conditions in different years. The sequence of the passage of phenophases by different species from year to year is preserved. Compared with the first decade of the 21st century, in the second decade, the start of the growing season became later (by 4 days on average), and the end of the growing season became earlier (by 8 days on average); the timing of the beginning of flowering also shifted by 4 days on average towards late dates. The duration of flowering of lilac species in 2015-2020 decreased by 5-6 days compared to the period of 2005-2010. The duration of the growing season was reduced by 12 days on average. All these phenomena are caused, obviously, with changes in the climatic parameters of the Bashkir Cis-Urals.

The study of the effect of biotic and abiotic factors on the duration of development of the gypsy moth (Lymantria dispar (L.)) and the establishment of thresholds for the development of stages in individuals of the West Siberian population of different latitudinal origin (56°33′ N., 76°37′ E.) (northern part of the range) and (53°44’ N,78°02’ E) (central part of the range) was carried out. We analyzed possible ways to accelerate the development of individuals of this species in the northern part of the range - reducing the number of instars, increasing the developmental rate of instars without reducing their number and lowering the development thresholds. It was found that the reduction in the number of larval instars is not a significant factor of the analyzed effect in this population. The threshold of late embryonic development in the West Siberian population is significantly lower than that defined for populations of the European part of Russia, a lower threshold for the development of individuals in the northern part of the population with a low sum of effective temperatures (SET) of early embryonic development is noted. The SET of early embryonic development has a significant impact on the acceleration of the development of active stages on the northern border of the area, and the smaller it is, the higher the impact. The high plasticity of the adaptation of the species to temperature conditions allows the gypsy moth to become established in new, more northern regions. This plasticity is provided both by natural selection and reduction of threshold temperatures of development, and by epigenetic mechanisms that allow adjusting the rate of development depending on the temperature conditions of the habitat.

The processes of biodeterioration of the unique monument of rock art in Western Siberia “Tomskaya Pisanitsa” were studied by complex of biological and mineralogical methods. The species composition of the lithobiotic community (bacteria, fungi, and lichens) was identified using a complex of cultural, morphological, and molecular genetic methods. It is shown that the destruction of the monument is a result of interrelated physical, chemical and biological processes, accompanied by a change in the properties of the rock and its biological colonization. The structure of microbial communities depends on local environment and successional processes. The development of biofilms with the dominance of cyanobacteria was observed on the rock zones of increased moisture and the formation of carbonate crusts. The problems of adaptation of the lithobiotic microorganisms to existence at the rock art monument “Tomskaya Pisanitsa” as well as their role in the processes of oxalate and carbonate biomineralization are discussed. The obtained results point to the danger of deterioration of the “Tomskaya Pisanitsa” and indicate the need to find new effective ways to protect this monument taking into account the accumulated scientific data.

The issues of climate warming and permafrost thawing are considered. A procedure for assessing the Arctic landscapes thawing based on the calculation of the normalized differential snow index (NDSI) is proposed. The factual material over the data of the global permafrost monitoring network is presented. Monitoring studies have shown that according to the results of NDSI calculation, abnormally early snowmelt was detected in 5 cases out of 23 years of observation at the Urengoy meteorological station and in 4 cases out of 23 years at the Tarko-Sale meteorological station. The absence of snow was observed during the indicated period in 13 cases at the technogenic sites of the Urengoy field, and in 8 cases at the Tarko-Sale field. With early snowmelt, the snow index NDSI decreases, and the depth of the seasonally thawed layer increases at the sites of the Urengoy field. The NDSI index can be used directly in assessing the duration of snow cover and early snowmelt, and indirectly in studying the depth of seasonally thawed layer. The results obtained are important for predictive estimates of the rate and extent of thawing and permafrost deformation, and for the prevention of emergency situations in the oil and gas complex.

To enhance oil recovery and intensify the development of fields with hard-to-recover reserves, including the deposits of high-viscosity oils, acid oil-displacing compositions with prolonged action have been developed on the principles of green chemistry using the method of deep eutectic solvents (DES). These compositions are based on surfactants and an adduct of inorganic acid, polyol and carbamide. As a result of experimental studies of acid-base equilibria in three-component systems with donor-acceptor interactions “boric acid - carbamide - polyol (glycerol, pentaerythritol)”, which are DES, the optimal compositions and concentration ranges of the components in acid compositions were determined. The results of laboratory studies and pilot tests of enhanced oil recovery technology with the use of acid compositions are presented. The compositions are compatible with mineralized formation waters, have a low freezing point ((-20)-(-50) °С) or a solid commodity form, low interfacial tension at the boundary with oil, are applicable in a wide temperature range (from 10 to 200 °C), provide effective oil displacement and prolonged impact on the formation. The acid GBA composition showed high efficiency under field conditions during pilot work in the experimental areas of the Permian-Carboniferous deposit of high-viscosity oil of the Usinsk oil field, developed under natural conditions and under thermal steam exposure, and was recommended for industrial use. The technology is environmentally friendly and technologically efficient. The industrial use of technologies for enhanced oil recovery and intensification of oil production is promising, which will make it possible to extend the profitable operation of fields at a late stage of development, to involve the fields with hard-to-recover oil reserves into development, in particular the deposits of high-viscosity oils, in a wide range of climatic conditions, including the northern regions and the Arctic.

The results of a comparative gas chromatographic - mass spectrometric (GC-MS) analysis of the composition of saturated and aromatic hydrocarbons, as well as heteroorganic compounds in petroleum oils isolated from a number of crude oils and natural bitumens, before and after selective chemical cleavage (chemolysis) of C-S and C-O bonds of sulphide and ether/ester bridges, respectively, are presented. The revealed difference in the structural-group and molecular composition of some types of compounds before and after chemolysis indicates that alkanes, alkyltrimethylbenzenes, naphthalenes, phenanthrenes, tetra- and pentacyclic aromatic hydrocarbons, and dibenzothiophenes are present in oils not only as molecular entities, but, partially, as structural fragments linked via sulphide and ether/ester bridges with other fragments in complex high-molecular entities. Ester-bound high-molecular С₂₀-С₃₀ homologues predominate among the bound alkanes. The proportion of C₁₃-C₁₆ homologues among alkyltrimethylbenzenes decreases after chemolysis. Chemolysis is accompanied by an increase in the proportion of С₃-С₄ naphthalenes in petroleum oils. The ratio of homologues among phenanthrenes changes after chemolysis: as a rule, the unsubstituted compound predominates over homologues. The ratio of fluoranthene and pyrene to benzanthracene and chrysene increases among tetracyclic aromatic hydrocarbons. The main trend in the changes in the composition of dibenzothiophenes after chemolysis is a sharp decrease in the proportion of unsubstituted homologue.

New methods of zeolite HZSM-5 modification with bismuth compounds are proposed. The choice of bismuth as a modifying agent is due to the systematisation and generalisation of the available literature data and experimental results of studying the chemistry and synthesis of bismuth compounds of various compositions. Phases in the resulting bismuth-containing zeolite systems were identified by X-ray phase analysis, and the state of bismuth in chemical compounds was determined. The number and strength of acid sites in the original and modified samples were determined by the method of temperature-programmed desorption of ammonia. The catalytic activity of zeolites was studied in the process of hydrogen-free processing of straight-run gasoline fraction of oil into high-octane gasolines. The effect of modification methods and process temperature on the structural-group hydrocarbon composition, the yield of gaseous and liquid reaction products was studied, and the octane numbers of the resulting gasolines were determined. It is shown that over the bismuth-containing zeolite catalysts, in comparison with unmodified zeolite, the yield of the target product, high-octane gasoline containing a smaller amount of aromatic hydrocarbons, increases, which makes it more environmentally friendly. It has been established that the production of high-octane gasolines that meet modern requirements for motor fuels is possible over modified zeolites within a wider process temperature range. Based on the studies performed, Methods for modifying the HZSM-5 zeolite with bismuth are proposed on the basis of the studies performed. The proposed methods make it possible to improve the efficiency of the catalyst in the process of upgrading the straight-run gasoline fraction of oil.

The content and composition of organic compounds in the bottom sediments of rivers and in soils sampled at the Arctic territory affected by diesel fuel spill were studied by gas chromatography-mass spectrometry. The composition of diesel fuel was studied. It was found that the groups of compounds characteristic of diesel fuel - n -alkanes, polycyclic aromatic hydrocarbons, alkylbenzenes and trimethylalkylbenzenes, sesquiterpanes, steranes, and hopanes were found mainly in the samples taken downstream at a distance of 0.5-20 km from the pollution source. The highest concentration of identified compounds was detected in bottom sediments and soil sampled at a distance of 20 km from the spill, which is associated with the structural features of the riverbed and bank line. In the samples taken at more remote sites (40-90 km), the traces of diesel fuel components were found only in bottom sediments.

Citrate complexes of transition metals, namely cobalt and molybdenum, used as active components in the synthesis of catalytic systems supported on alumina for hydrotreatment of heavy oil fractions have been studied. Cobalt nitrate hexahydrate and polyoxomolybdate (molybdenum blue) obtained by mechanical activation of molybdenum disulphide (MoS₂) powder were used as initial compounds. Thermogravimetric analysis of the samples was carried out during their heating from 25 to 750°C at a rate of 15°C/min in air. A study by thermogravimetric analysis shows that the order in which the active components are introduced significantly affects the thermal stability of the sample. Despite the general similarity of the profiles, a shift of the temperature range of citrate complex decomposition is observed, depending on the order of active components introduction. Presumably, this may be due to the different degrees of Mo and Co availability for the formation of compounds with citrate ligands. It is shown that the most thermally stable system is the one in which the Co-containing component and citric acid are introduced first, and then the alcohol solution of molybdenum blue; the least stable system is the reverse one, in which the alcohol solution of molybdenum blue is introduced first, then citric acid and the Co-containing component are added.

The composition and distribution of organic compounds in the bottom sediments of the Tom River near the city of Yurga (the Kemerovo Region - Kuzbass) in 1995, 2005 and 2018 are determined by gas chromatography - mass spectrometry. The compounds included hydrocarbons ( n -alkanes, isoalkanes, naphthenes, alkylbenzenes, and polycyclic aromatic hydrocarbons), oxygen-containing compounds (carboxylic acids and their ethyl and propyl esters). The data on the group composition of the most dangerous pollutants, polycyclic aromatic hydrocarbons, are presented. The pattern of changes in the technogenic load on the river system made by the Kuzbass enterprises over different years has been established. The highest contribution into the pollution of the Tom basin was determined to be in 2005. This contribution is directly due to the industrial activities at the enterprises of Kuzbass.

The process of removing sulphur-containing compounds from the diesel fraction has been carried out and investigated. The systems based on coordinating polar solvents (DMF and DMSO) and metal salts (CuCl₂, CoCl₂, MnCl₂, Mn(TFA)₂, Cu(TFA)₂) were used as extractants. It has been established that the presence of metal salts in extraction systems increases the degree of removal of sulphur-containing compounds from the diesel fraction from 11 to 49 % and reduces the content of polycyclic aromatic hydrocarbons by 33 %. It is assumed that the addition of metal salts to the solvent enhances its acceptor properties, which is manifested in the enhancement of its extractability.

The results of rheokinetic measurements of changes in the fluidity of gel-forming compositions of various natures obtained by the methods of rotational and selection viscometry are presented. A technique for processing measurement results obtained by means of vibrational viscometry in measuring vessels of different sizes has been developed. Two directions of the interpretation of nonmonotonic rheokinetic dependences are considered.

Investigation of the dispersed organic matter of the rocks at the Ust’-Maiskaya wildcat area was carried out. The data on the features of dispersed organic matter composition in the range of 2868.731 - 3057.68 m are presented. Alkanes, mono-, bi-, tri-, tetra- and pentacyclic arenes, bi-, tri-, tetra- and pentacyclanes, tetracyclic naphthenoaromatic hydrocarbons, dibenzothiophenes have been identified among hydrocarbons studied by means of gas chromatography - mass-spectrometry. Perylene and traces of nickel metalloporphyrins were also determined spectrophotometrically. It is shown that the initial organic matter was formed under the conditions of reduction and suboxidation, with a significant contribution from both the terrestrial vegetation and phytoplankton. The presence of nickel porphyrin and perylene complexes in some sections of the log suggests the shallowness of the sedimentation basin and the proximity of the coastline during the period of OM accumulation. The calculated vitrinite reflectance indicates that the differences observed for the MK₂ stage of catagenesis correspond to the main zone of oil generation.

The composition of cracking products of high-sulphur shale oil from the Kashpir deposit is investigated under different process conditions (duration and temperature). The characteristic features of the influence of heat treatment conditions on changes in the composition of liquid products of oil shale cracking are established. It is shown that the cracking of oil shale organic matter is accompanied by the formation of a wide range of low-molecular sulphur-containing compounds that enter the composition of oils. The changes in the group composition of sulphur-containing compounds of oils have been studied, the features of the distribution of thiophene derivatives, benzo- and dibenzothiophene derivatives in the composition of liquid cracking products are revealed. It is shown that the depth and rate of destruction of sulphur-containing structural fragments of kerogen is significantly affected by the temperature and duration of the process. The data obtained will improve understanding of the patterns of thermal transformations of sulphur-containing structural fragments of organic matter in high-sulphur oil shale during cracking.

Results of the application of benzene oxidation product (BOP), formed in barrier discharge, as an improving component of the inhibiting additive for paraffinic and highly paraffinic petroleum are presented. The proposed additive consists of a copolymer of alkyl acrylates with dodecylamine acrylate and BOP at a ratio of 15:1 wt. %. Benzene oxidation by air in a barrier discharge proceeds predominantly to phenol (~77.3 wt. %), diatomic phenols, and an insignificant amount of macromolecular compounds. The effect of the additive (in combination with BOP) in the amount of 0.03-0.05 wt. was evaluated relying on changes in the rheological characteristics and freezing point of paraffinic and highly paraffinic petroleum with a high content of resins and asphaltene components. The composition containing polymer and BOP additionally reduces the amount of asphaltene-resin-paraffin deposits by 1.5-2.5 g, which gives an increase in inhibitory capacity by 10-12 %. The depression of the freezing point of petroleum is 46 ºС on average. The dynamic viscosity of petroleum under study decreases in the presence of the additive by a factor of 2.2 on average.

A new multifunctional oil-displacing MIСA composition has been developed by the researchers of the IPC SB RAS for the purpose of oil recovery enhancement. The MIСA composition possesses oil-cleaning properties and is able to align the displacement front by increasing the reservoir sweep. Laboratory tests of MICA and its components (glycerol, carbamide, and boric acid) were carried out against the reservoir microflora of three groups: hydrocarbon-oxidising and denitrifying bacteria (HOB and DNB, respectively) as possible agents for enhanced oil recovery, and sulphate-reducing bacteria (SRB), as a corrosion-dangerous group. It is shown that HOB exhibited positive reactions to all versions of components introduction, as well as to the solutions of the composition diluted by a factor of 20-50. The presence of boric acid, in particular in the binary systems with carbamide and glycerol, suppressed the growth of DNB in spite of the stimulating action of glycerol and carbamide. The multifunctional MICA composition had a positive effect on the DNB count at 20-50 dilution. In the course of pilot work in 2020-2021 at the Usinskoye oilfield, a positive effect of the MICA composition on the growth of HOB and DNB groups and the inhibition of the SRB count was revealed. The effect decreased after 8-10 months due to manifold dilution of the composition and its displacement. This action of MICA and its components may be evaluated by two positive effects: an increase in the counts of HOB and DNB, as potential agents of oil displacement, and inhibition of the activity of SRB, as an agent of sulphide corrosion of equipment.

Changes in the composition of SARA fractions (Saturated, Aromatics, Resins, Asphaltenes) of methane crude oil from the Zyuzeevo oilfield (the Republic of Tatarstan) during thermal cracking are investigated. Cracking was carried out at 450 °C for 120 min in the isothermal mode. The data on mass balance, the composition of liquid and gaseous products of cracking were obtained. It is shown that the composition of hydrocarbons in liquid products and the yield of side gaseous and solid products depend on the composition of initial SARA fractions. Thus, the yield of solids is maximal from asphaltene fraction cracking, while the largest amount of gases are formed from resin fraction cracking. It has been established that cracking of SARA fractions involves the formation of new components that were absent in the initial feedstock. It is shown that the structural features of initial resin and asphaltene molecules affect the content and composition of their cracking products.

The state of the vegetation cover at six hydrocarbon fields of the Parabel district of the Tomsk Region has been studied relying on satellite data. An example of the practical application of the procedure developed for the quantitative assessment of the state of vegetation cover at oil-and-gas producing territories on the basis of the values of vegetation indices obtained using the satellite data MODIS (Moderate Resolution Imaging Spectroradiometer) is shown. It is established that changes in the values of vegetation index EVI (Enhanced Vegetation Index) over the 12-year period (2011-2022) have a positive trend, with the maximum values recorded in 2020. This may indicate the restoration of vegetation and improvement of the environmental situation.

The physicochemical properties of hard-to-recover viscous oil with high paraffin content were evaluated relying on the analysis of information from the oil characteristics database, compiled at the Institute of Petroleum Chemistry SB RAS. It is established that Russia is distinguished by the largest reserves of viscous paraffin oil (VPO) on the territory of Eurasia, where almost three quarters of the reserves are concentrated in the Volga-Ural oil and gas basin. The characteristics of the properties of these oils under various conditions of their occurrence have been analysed. It is shown that VPO is more confined to terrigenous rocks, in which the reserves are 4.6 times greater than those in carbonate formations. The physicochemical properties of VPO in the productive formations differing from each other in permeability and porosity are considered. It is established that in the case of high permeability of formations, the density of VPO increases (oil becomes heavier), coking ability, sulphur and resin content grow, the content of paraffins and the gas factor decrease. Viscous paraffin oils in reservoirs with different permeability have a positive pour point and are characterized by low gas content. In medium- and highly porous formations, VPOs are heavy, sulphurous, medium-resinous and medium-asphaltene, with low gas content. It is shown that in highly permeable and highly porous reservoirs, the content of paraffins in VPO is minimal, and, quite contrary, the content of paraffins in oil is the greatest in low-permeable and low-porous reservoirs. The properties of high-hardening VPOs are revealed, which significantly differ from the properties of oils with a negative pour point. High-setting VPOs differ from low-setting oils by medium density (low-setting oils are heavy), but very high viscosity; higher content of paraffins and oxygen, but lower content of resins, asphaltenes, sulphur (almost 2 times) and nitrogen; the gas factor is higher by 81 %.

The morphology and structure of the mesophase in the series: coal tar pitch (CTP) - α-fraction of CTP - carbonised α-fraction after heating to 1200 °C, were studied by scanning electron microscopy, X-ray phase and X-ray structural analysis. The X-ray structural parameters were determined: longitudinal and transverse dimensions of the lamellae and the thickness of packages, the distance between the lamellae and the number of lamellae in the formed packages. It is shown that the two-dimensional structures of the carbon mesophase are ordered into three-dimensional packages during the formation of semi-coke under CTP heating. It is established that the carbon structure of CTP and its α-fraction is represented by the turbostratic and graphite-like phases. The sizes of the packages formed by the lamellae during structuring in the transverse direction in the studied samples are of the order of 18-25 Å, in the longitudinal direction 46-63 Å, the average distance between the lamellae in the studied samples is 3.46-3.52 Å.

Despite the low mean annual air temperature and low precipitation, subaerial suprapermafrost aquifer taliks are formed in some cases in the continuous permafrost zone of Central Yakutia. The paper presents an analysis of the seasonal and interannual dynamics of ground temperature in contrasting geocryological conditions - in areas of permafrost spread from the surface and in suprapermafrost subaerial taliks - of the key area of Levaya Shestakovka 20 km southwest of Yakutsk. The permafrost table in this area a occurs at depths from 0.5 to 20 m. The highest ground temperatures are typical of the area of aquiferous suprapermafrost taliks confined to gentle slopes composed of sandy sediments and covered with pine woodland. The thickness of the seasonally frozen layer reaches 3 m, and the depth of zero annual amplitudes varies from 6 to 12 m. Thawed deposits are preserved due to the continuous filtration of groundwater in them. The lowest ground temperatures are characteristic of the mire and the river floodplain. The depth of seasonal thawing varies from 0.5 to 1.0 m, and the depth of zero annual amplitudes exceeds 15 m. In recent years, slow freezing of the taliks from below has been noted due to mild cooling of the strata underlying the thawed aquifers. Beyond the area of taliks, weak multidirectional changes in ground temperature have been recorded.

Based on observations on 12 largest rivers of East Siberia (Lena, Vilyuy, Kolyma, Aldan, Olenek, Vitim, Indigirka, Amga, Olekma, Anabar, Yana, and Chara) during summer low-water runoff in 2007-2011, the main features of the chemical composition and physical properties of river water have been determined. It is found that favorable oxygen regime, higher chemical oxygen demand and color of water, higher concentration of total iron and ammonium ions, and moderate salinity are characteristic of the investigated rivers. The territory of East Siberia is characterized by an ubiquitous distribution of permafrost. The thickness of seasonally thawed layer within river catchments is extremely variable in the studied region. Using canonical-correlation analysis, it was found that concentrations of specific components of ionic constituents (water hardness, calcium, magnesium, bicarbonates, sulfate ions, and salinity) depend on the active layer thickness (ALT). Herewith, the deeper the active layer in a catchment, the higher the concentration of mentioned components of ionic constituents. This pattern is explained by the fact that permafrost serves as a confining barrier that prevents infiltration of surface water through deep mineral horizons thus restricting water saturation with mineral ions. The increase in ALT noted in recent decades in the permafrost zone of the northern hemisphere may continue in the current century. Therefore, knowledge of how the concentration of soluble biogeochemical constituents in the rivers depends on ALT of permafrost in the catchments is valuable for assessment of potential changes in the chemical composition of river water in the permafrost zone in the future.

To date, the issue of using ice-based composite materials for engineering constructions under harsh weather conditions remains poorly understood. Application of ice as construction material is favored by its ease of use and low manufacturing cost. In turn, ice can be reinforced with various additional materials that change its physical and mechanical properties as part of an ice-based composite material. The results of an experimental study of the behavior of reinforced ice beams under pure bending are discussed. As a reinforcement, longitudinal rods with different physical and mechanical characteristics made of fiberglass and polypropylene were used. The results of the study were compared with previous experiments on loading ice beams reinforced with steel armature. It is concluded that the proposed materials can be efficiently used to improve the mechanical characteristics of the ice. There is a positive effect of polypropylene on the deformability of the samples, as well as their bearing capacity. Schematic diagrams of deformation of ice beams reinforced with steel and fiberglass reinforcement and with polypropylene rods are presented. Prospects for the use of fiberglass and polypropylene rods in the ice-based composite materials are discussed.

The article presents the initial assumptions of the predictive model of changes in the temperature regime of the frozen soil massif in the case of surface flooding. Heat exchange of the soil surface with the atmosphere through a shallow (up to 1 m) water cover is described using an effective heat exchange coefficient, which includes the intensity of mixing of the water layer during the summer season. The results of calculation of two parameters of the new thermal condition of the frozen massif (temperature at a depth of zero annual amplitude and the maximum depth of seasonal thawing) appearing as a result of flooding are presented. In addition, the rate of transformation to the new condition is considered. Significant warming of the frozen foundation soil occurs in the case of intense mixing of the water layer during the summer season. If the mixing process does not take place in the water reservoir of a shallow depth, its cooling effect is possible. In deeper reservoirs, the warming effect is possible, but it is weaker than that under mixing conditions. This analysis has been performed for the least studied element of the “roadway embankment - reservoir - frozen soil” technical system in order to control the correctness of the calculation procedure in a more complex case for a two-dimensional process. The results of mathematical modeling of the temperature field in the frozen base of the roadway in contact with shallow water basin are presented. It is demonstrated that the frozen base warms up essentially, if the water layer is intermixed intensively (by wind) in summer time. The initial temperature state may be preserved during the whole period of road exploitation, if the summer mixing of water is blocked by fairly simple technical measures that are proposed in this paper.

Data on the snow cover in the middle and southern taiga subzones of the northeast of European Russia (Komi Republic) are analyzed. Field surveys were carried out in the second half of March in 2005-2007 and 2014-2015 on open flat spaces and in the intercrown spaces of forest stands. The studies were conducted at the same monitoring points, which allowed for a correct analysis of spatial and temporal differences. By route observations, measurements of the snow depth and snow density were carried out, and the values of snow water equivalent were calculated. The obtained data were compared with the results of measurements at the stations of the federal meteorological service. Schematic maps of spatial distribution of snow cover parameters were constructed. The influence of the landscape on snow accumulation was shown: snow depth increased in intercrown spaces of forest stands; in open areas, snow compaction with a decrease in snow depth took place. The wide territorial distribution of measurement points made it possible to estimate the longitudinal effect and the related relief conditions on the snow cover parameters. The maximum snow accumulation was observed along the Ural Mountains in the eastern part of the study area, where intense moisture condensation and precipitation take place. Snow depth and snow water equivalent in the foothills increased to the east. At the same time, the zone of increased snow density was noted in the western part of the Komi Republic. The obtained field data are consistent with long-term observations by other authors, as well as with the results of measurements at the network of weather stations.

Thermokarst plains with fluvial erosion include two genetically different types of surface: slightly undulating watersheds and lowered surfaces of khasyreys (drained thermokarst lakes with secondary thermokarst lakes). The research deals with a comparative analysis of statistical distributions of the areas of thermokarst lakes and secondary lakes. Using statistical criteria and remote sensing data for eight key sites in different natural conditions, such as Yamal and Taz peninsulas, the Kolyma Lowland, and the Penzhina River valley, we determined statistically significant differences in the area distributions of thermokarst lakes within different genetic types of the surface. Statistical analysis shows that the areas of thermokarst lakes correspond to an integral-exponential distribution. This allows us to conclude that a dynamic equilibrium is established within each type of the surface in the course of the initiation, growth, and drainage of thermokarst lakes. Though the parameters of thermokarst lakes differ significantly, we find a correlation between the distribution parameters of lake areas within the main surface of thermokarst plains with fluvial erosion and the surface of khasyreys with secondary lakes.

Information about the life and work of an outstanding scientist Mikhail Ivanovich Sumgin is presented. His contribution to the development of a young science of frozen rocks and related phenomena-geocryology is discussed.