bluuebunny/crossref_metadata_2025 huggingface dataset:
THE FIRST DATA ON THE NUTRITION OF THE URAL CAVE BEAR (MAMMALIA, CARNIVORA, URSIDAE, URSUS (SPELAEARCTOS) KANIVETZ VERESTCHAGIN, 1973) BASED ON THE RESULTS OF THE ANALYSIS OF ISOTOPES 13C and 15N
Authors: Kosintsev P. A. , Simonova G. V. , Konovalova K. Yu.
Published: April 2024

The first data on the content of isotopes 13C and 15N in the collagen of 16 bones of the Ural cave bear (Ursus (Spelaearctos) kanivetz Verestchagin, 1973) were obtained from the Tayn (Secrets) cave (55°25' N, 57°46' E). The bones date from the middle of MIS 3. The bones of males and females aged about 2 years, about 3 years and older than 4 years were studied. There are no noticeable differences in isotope signatures between individuals of different ages and different sexes. Since the second year of life, cave bears have been eating plant food on their own. The values of δ13C and δ15N of the Ural cave bear are close to the values for U. (S.) spelaeus ingressus.
SYNTHESIS OF 1-[ω-(BROMOPHENOXY)ALKYL]-3-NAPHTHALENYLMETHYL DERIVATIVES OF URACIL AND THEIR ANALOGUES AS PROBABLE INHIBITORS OF HUMAN CYTOMEGALOVIRUS REPLICATION
Authors: Paramonova M. P. , Gureeva E. S. , Ozerova A. A. , Snoeck R. , Andrei G. , Alexandrov D. A. , Khandazhinskaya A. L. , Novikova M. S. , Kochetkov S. N.
Published: April 2024

A new series of 1-[ω-(bromophenoxy) has been synthesizedalkyl]-uracil derivatives containing naphthalene-1-yl-, naphthalene-2-yl-, 1-brominaphthalene-2-ilmethyl, benzyl and anthracene-9-ilmethyl fragments in position 3 of uracil. Antiviral properties of synthesized compounds against human cytomegalovirus were studied. It was found that the compound, which has a bridge consisting of five methylene groups, has high anti-cytomegalovirus activity in vitro. uracil
D2-LIKE DOPAMINE RECEPTOR DISTRIBUTION IN THE BRAIN OF RATS WITH DIFFERENT TYPES OF GENETIC EPILEPSY
Authors: Tsyba E. T. , Birioukova L. M. , Midzyanovskaya I. S. , Surina N. M. , Abbasova K. R.
Published: April 2024

The study investigated D2-like dopamine receptor (D2DR) binding densities in cortex and striatum between rats with absence and/or audiogenic genetically determined epilepsy and normal Wistar rats by autoradiography. It was shown that D2DR binding density was lower in the dorsal and ventrolateral aspects of nucleus accumbens in epileptic vs non-epileptic rats. Additionally, audiogenic rats had higher motor, somatosensory cortex, and dorsal striatum binding as in contrast with non-audiogenic groups. This data suggests that there is a common neuronal circuit involved in the pathogenesis of generalized epilepsy of both convulsive and non-convulsive forms.
THE EFFECT OF THE AGONIST CHOLECYSTOKININ-4 D-GB-115 ON THE CHARACTER OF MOTOR ACTIVITY OF PARAMECIUM CAUDATUM
Authors: Gruzdev G. A. , Soboleva L. V. , Kamensky A. A.
Published: April 2024

The study investigated the effect of GABA in various concentrations and D-GB-115 at a concentration of 10–10 mol/ml on the behavior of Paramecium caudatum. It has been shown that GABA increases motor activity and changes the movement strategy of these protozoa, and the dose-effect relationship is domed, which can be explained by the presence of two types of GABA receptors in the outer membrane of paramecia: GABA-A and GABA-B. The range of active concentrations of GABA ranges from 10–6 to 10–16 mol/ml. The effect of pharmacological agents interacting with the GABA system on the behavior of infusoria: nembutal and D-GB-115.
IMMUNOCOMPETENT MICE AS A MODEL FOR PRECLINICAL STUDIES OF mRNA VACCINES IMMUNOGENICITY
Authors: Shkurnikov M. Yu. , Tonevitskaya S. A. , Stepanova E. V. , Slobodov S. A.
Published: April 2024

Conducting preclinical studies of mRNA vaccines is complicated by the lack of relevant animal models of the human immune system. Immunocompetent mice are widely used in biomedical research. However, critical differences in the genetics and immune system of mice and humans prevent the study of unique human immune responses in mice. Within the framework of this work, the possibility of modeling the cytotoxic T-cell response to mRNA vaccines encoding the S-protein of the SARS-CoV-2 virus was investigated. High-affinity peptides from S-protein were analyzed for the most frequent allelic variants of human MHC-I, two immunocompetent mouse lines (C57BL/6, BALB/c) and an outbred mouse model of IRC. The results of computer modeling have shown that mouse models can be used in preclinical studies of mRNA vaccines against SARS-CoV-2. Mouse MHC-I is able to present virus peptides that are highly affine for human MHC-I. Moreover, the immunogenicity of some of them has already been confirmed by examining blood samples from patients who have had COVID-19.
NEW HYBRID STRUCTURES BASED ON MEMANTHINE AND EDARAVONE MOLECULES
Authors: Grigoriev V. V. , Aksinenko A. Yu. , Shevtsova E. F. , Goreva T. V. , Veselov I. M. , Gabrelyan A. V. , Bachurin S. O.
Published: April 2024

New hybrid structures based on memantine and edaravone molecules, in which the pyrazolone ring and adamantane fragments are linked by an alkyl linker, have been synthesized. It was found that in addition to the ability to block the intrachanal site of NMDA receptors, new hybrid compounds exhibit the property of blockers of the allosteric site of NMDA receptors, which is not inherent in memantine and edaravone preparations. The most active hit compound was determined, which, along with the properties of a two-site blocker of the NMDA receptor, exhibits a pronounced activity as an inhibitor of lipid peroxidation, similar to the drug edaravone.
A NEW SPECIES OF HAPALODECTES (HAPALODECTIDAE, MESONYCHIA) FROM THE PALEOCENE OF MONGOLIA
Authors: Lopatin A. V.
Published: April 2024

Hapalodectes paradux sp. nov. (Hapalodectidae, Mesonychia) is described on the base of the dentary fragment with М2–М3 from the Tsagan-Khushu locality in Mongolia (Upper Paleocene, Naran Bulak Formation, Zhigden Member). The M2 and M3 are approximately the same size, with a high protoconid, anteriorly displaced reduced metaconid, anterolingually directed protocristid, very deep posterior notch, narrow talonid, and distinct hypoconid, entoconid and hypoconulid. Based on dental characters, the new species is presumably related to the base of the lineage of Hapalodectes that dispersed to North America at the beginning of the Eocene. Tsagan-Khushu is the only known locality where two species of Hapalodectes co-occur (larger H. dux Lopatin, 2001 and smaller H. paradux sp. nov.).
INTERACTION OF MRNA WITH THE C-TERMINAL DOMAIN OF PCID2, A SUBUNIT OF THE TREX-2 COMPLEX, IS REQUIRED FOR ITS EXPORT FROM THE NUCLEUS TO THE CYTOPLASM IN DROSOPHILA MELANOGASTER
Authors: Vdovina Y. A. , Georgieva S. G. , Kopytova D. V.
Published: April 2024

Following the transcription step, the newly synthesized mRNA is exported from the nucleus to the cytoplasm and further to the translation site. The TREX-2 complex is involved in the step of mRNA export from the nucleus to the cytoplasm. This complex in Drosophila melanogaster consists of four proteins: Xmas-2, PCID2, ENY2, Sem1p. In our work, we have shown that deletion of the C-terminal sequence of PCID2 leads to a decrease in the interaction of the protein with RNA and to impaired mRNA export from the nucleus to the cytoplasm in D. melanogaster.
THE HUMAN TREX-2 COMPLEX INTERACTS WITH SUBUNITS OF THE ORC COMPLEX
Authors: Kurshakova M. M. , Georgieva S. G. , Kopytova D. V.
Published: April 2024

The TREX-2 protein complex is the key complex involved in the export of mRNA from the nucleus to the cytoplasm through the nuclear pores. Previously, a joint protein complex of TREX-2 with ORC was isolated in D. melanogaster, it was shown that the interaction of TREX-2 with ORC is necessary for efficient mRNA export from the nucleus to the cytoplasm. In this work, we show that the TREX2-ORC joint complex is also formed in human cells.
SELECTION OF AN AMINO ACID SITE WITH ONE OF THE FASTEST CLEAVAGE KINETICS BY THE ENDOSOMAL PROTEASE CATHEPSIN B FOR POTENTIAL USE IN DRUG DELIVERY SYSTEMS
Authors: Khramtsov Y. V. , Georgiev G. P. , Sobolev A. S.
Published: April 2024

Based on known literature data, six peptide sequences were selected that are potentially capable of being rapidly cleaved by the endosomal protease cathepsin B. For comparison, cathepsin B cleavage of common linker sequences, polyglycine and polyglycine-serine, was also studied. Different ends of these peptides were labeled with sulfoCyanine3 and sulfoCyanine5 fluorescent dyes, between which Förster resonant energy transfer (FRET) is possible. The kinetics of cleavage of peptides by cathepsin B was studied on a multimodal plate reader by FRET signal reduction. FKFL and FRRG cleavage sites have been shown to be the most suitable for potential use in various drug delivery systems. These sites are much more efficiently cleaved under slightly acidic conditions of endosomes than at neutral extracellular pH.
AN INCREASE IN THE INFECTIVITY OF THE HUMAN IMMUNODEFICIENCY VIRUS WITH MODIFICATION OF THE CCR5 GENE RECEPTOR OF SENSITIVE CELLS
Authors: Nosik D. N. , Kalnina L. B. , Selimova L. M. , Pronin A. V.
Published: April 2024

Identification of a natural mutation of the ccr5 gene in humans which makes them resistant to HIV-1 infection, has opened a new direction for the development of alternative treatment approaches through genome editing. The human immunodeficiency virus, when infecting CD4+ cells, uses one of two chemokine co-receptors of the plasma membrane. During infection and in the early stages of infection, strains using the CCR5 protein circulate, while the later ones use the CXCR4 protein. It cannot be ruled out that there is a complex relationship in the regulation of the expression of these receptors, which in turn can affect the replication of the virus in cells that normally do not have the CCR5 protein on the membrane. To study the effect of ccr5 gene correction on HIV-1 replication in the in vitro system, exactly like this MT-4 cell line was used. The study of virus replication showed that genetic modification of the ccr5 gene of MT-4 cells led to an increase in the activity of the studied HIV-1 strains, and this increase was most pronounced in homozygous variant. Our results indicate that editing the genome of human cells should be treated with great caution and that such studies require in-depth and comprehensive study.
SPECTRAL ANALYSIS OF HEART RATE VARIABILITY BASED ON THE HILBERT-HUANG METHOD
Authors: Grinevich A. A. , Chemeris N. K.
Published: April 2024

Analysis of heart rate variability (HRV) is widely used for noninvasive assessment of the state of its regulation systems. The aim of the research was to evaluate the capabilities of the Hilbert-Huang method for calculating spectral parameters of HRV in comparison with the commonly used Fourier analysis. Fourier analysis allows to estimate averaged spectral amplitudes and power of HRV oscillations in fixed frequency intervals, which are associated with the activity of sympathetic, parasympathetic and humoral regulation systems. Using the Hilbert-Huang method, we revealed 4 spectral components, described by Gauss functions, in which HRV oscillations are concentrated, and showed the absence of fixed boundaries between them. The obtained energy quantitative characteristics of the spectral components of heart rhythm oscillations can serve as the basis for diagnostic methods of its regulation, supplementing the commonly used ones.
DIFFERENT PROTEIN GROUPS INVOLVED IN TRANSCRIPTION REGULATION IN GENES OF DEVELOPMENT AND HOUSEKEEPING IN DROSOPHILA
Authors: Zhimulev I. F. , Vatolina T. Yu. , Pokholkova G. V. , Antonenko O. V. , Maltseva M. V.
Published: April 2024

Antibodies to histone modifications and an insulator protein involved in the processes of transcription initiation and elongation are mapped in Drosophila polytene chromosomes. The CHRIZ protein (chromatin insulator) and H3K36me3 histone modification (RNA elongation) are detected only in the localization of housekeeping genes (interbands and gray bands of polytene chromosomes) and never in the regions of development genes (black bands and large puffs arising from them). Antibodies to H3S10P histone modification, which is associated with the initial elongation of the RNA strand during transcription, are found exclusively in small puffs, but not in housekeeping gene localization sites or large ecdysone-induced puffs, where housekeeping genes are localized. Antibodies to H4R3me2 histone modification (a co-repressor of the ecdysone receptor) are detected only in large α-induced puffs.
SLEEP WITH OPEN EYES IN TWO SPECIES OF DEER, THE INDIAN SAMBAR (RUSA UNICOLOR) И SIKA DEER (CERVUS NIPPON)
Authors: Lyamin O. I. , Siegel J. M. , Nazarenko E. A. , V Mnh , Rozhnov V. V.
Published: April 2024

The relationship between postures, sleep stages and eye state was established in two species of deer, the Indian sambar (Rusa unicolor) and sika deer (Cervus nippon), based on video recording. In both species, the state of rest or behavioral sleep was recorded in the sternal position, holding the head above the ground, and in the lateral position, with the head resting on the croup or on the ground. Rest accounted for at least 80% of the time in these positions. Based on behavior criteria a substantial portion of rest represented slow-wave sleep. Episodes of rapid eye movements (REM sleep) were recorded in the lateral position. They did not exceed 2 min. When the deer were in the sternal posture, they kept their eyes open most of the time: on average 96% of the time in sambars and 82% in sika deer. Episodes of the open eye in this posture lasted up to 8.4 min in sambars and up to 3.3 min in sika deer. In the lateral position, such episodes were 4 and 1.5 times shorter. Sleeping with open eyes in ungulates may be an important mechanism of maintaining vigilance.
EXPRESSION LEVEL OF FLOWERING TIME GENES (CONZ1, GIGZ1A, GIGZ1B, FKF1A, FKF1B) IN SEEDLINGS UNDER LONG DAY CONDITIONS DIFFERENTIATES EARLY AND LATE ZEA MAYS L.
Authors: Arkhestova D. Kh. , Anisimova O. K. , Kochieva E. Z. , Shchennikova A. V.
Published: April 2024

Twenty inbred lines of maize Zea mays L. were characterized by the duration of phenophases, including the timing of flowering and ripeness. The expression of key genes for initiation of flowering, CONZ1, GIGZ1a, GIGZ1b, ZmFKF1a, and ZmFKF1b, was studied in seedlings of six maize lines with different ripeness periods under long photoperiod conditions. A significantly lower level of transcripts of all five genes was found in early ripening lines in comparison with late ripening accessions. A similar expression of the paralogous GIGZ1a and GIGZ1b genes was shown, as well as a significant predominance of ZmFKF1a expression in comparison with its paralogous gene ZmFKF1b.
COMPOSITION OF FATTY ACIDS OFTHE TOTAL LIPIDS IN PARR AND SMOLTS OF ATLANTIC SALMON SALMO SALAR L. REARED UNDER DIFFERENT LIGHTING MODESIN AQUACULTURE
Authors: Provotorov D. S. , Murzina S. A. , Voronin V. P. , Kuritcyn A. E. , Nemova N. N.
Published: April 2024

In the framework of this study, an experiment was carried out on the introduction of constant artificial lighting (24LD) into the standard technology for growing salmon juveniles under conditions of the southern region (Republic of North Ossetia-Alania) and its effect on the composition of fatty acids (FA) of total lipids in muscles and liver parr and smolts of the Atlantic salmon Salmo salar L. It has been established that the FA spectrum of fish is characterized by a change in the key FA factors, indicating the full completion of smoltification and the readiness of smolts for new habitat conditions: a significant increase in the content of polyene FAs (PUFAs) due to (n–3)PUFA, and in them FA of the “marine” type – 22:6(n–3), high values of the ratios (n–3)/(n–6)PUFA, 22:6(n–3)/18:3(n–3).The most significant changes were noticed in the muscles, and for all experimental groups it was found that a decrease in saturated fatty acids (SFA) and an increase in total lipid unsaturation occurs primarily due to PUFAs, while monoene FAs decrease along with SFAs. The data of experimental studies of the lipid and fatty acid composition of salmon youngs, as well as a higher proportion of smolts in the studied groups of fish, indicate that the most successful process of smoltification restructuring occurred in groups with constant lighting and 24 hours feeding and a natural regime of lighting and feeding.
INFLUENCE OF SEED TREATMENT WITH SALICYLIC ACID ON THE CARBONIC ANHYDRASE ACTIVITY, PHOTOSYNTHESIS RATE, STOMATAL CONDUCTANCE AND PIGMENTS CONTENT IN WHEAT LEAVES AT ZINC EXCESS
Authors: Ignatenko A. A. , Nilova I. A. , Kholoptseva E. S. , Titov A. F. , Kaznina N. M.
Published: April 2024

We studied the effect of seed treatment with salicylic acid (SA) on the carbonic anhydrase (CA) activity, photosynthesis rate, stomatal conductance and pigments content in wheat leaves at optimal zinc content (2 μM) or zinc excess (1500 μM). It was shown for the first time that at an optimal zinc content seed treatment with SA leads to an increase in CA activity and stomatal conductance compared to untreated plants without affecting the photosynthesis rate. At an zinc excess seed treatment with SA increased the decrease in CA activity, but the photosynthesis rate was higher than in untreated plants, apparently due to an increase in the chlorophylls and carotenoids content and stomatal conductivity. It is concluded that SA along with other non-hormonal factors and hormones, is involved in the protective and adaptive reactions of wheat plants to an zinc excess in the environment.
FORMATION OF A-TYPE GRANITES IN THE YENISEI RIDGE IN THE CRYOGENIAN PERIOD DURING THE TECTONIC TRANSFORMATION OF THE REGION (SOUTHWESTERN MARGIN OF THE SIBERIAN CRATON)
Authors: Vernikovskaya A. E. , Vernikovsky V. A. , Matushkin N. Yu. , Wingate M. T. D. , Romanova I. V. , Kadilnikov P. I. , Bogdanov E. A.
Published: April 2024

We consider the evolution of the A-type granite magmatism in the Cryogenian period during the tectonic transformation of the Yenisei Ridge from a postcollisional setting to the early development stage of an active continental margin. We report geochronological and geochemical data for A-type granites of two intrusions – the Strelka pluton belonging to the Glushikha postcollisional complex (752–718 Ma) and the Yagodka pluton of the Tatarka active continental margin complex (711–629 Ma). The new U-Pb and Ar/Ar geochronological data for the postcollisional Glushikha plutons indicates that the age intervals for these complexes can be combined, showing the uninterrupted evolution of A-type magmatism during the change in tectonic setting of the region.
INFLUENCE OF ORIENTATION OF ACTIVATING TECTONIC FAULTS ON SAFETY OF A SYSTEM OF ISOLATION OF RADIOACTIVE WASTE
Authors: Malkovsky V. I. , Petrov V. A. , Minaev V. A.
Published: April 2024

Methods of mathematical modeling were used for estimating an influence of tectonic faults activation of safety of a facility for final isolation of high-level radioactive waste at the site Yeniseiskiy (Krasnoyarsk region) by methods of mathematical modeling. A 3–D model of radionuclides transport by groundwater was considered taking into account a heterogeneity of rock permeability. Faults of different orientation were considered. We showed that a formation of new near-meridional faults or an activation of ancient ones did not exert a substantial influence on velocity of radioactive pollution propagation in underground medium. Near-latitudinal faults can affect the radionuclides to a more extent. We considered a possibility to confine this influence due to a technogeneous decrease of rock permeability within a relatively short interval of the fault zone.
DEVELOPMENT OF A METHODOLOGY FOR MONITORING THE STATE OF GAS HYDRATE DEPOSITS OF THE EAST SIBERIAN SHELF
Authors: Cheverda V. A. , Bratchikov D. S. , Gadylshin K. G. , Golubeva E. N. , Malakhova V. V. , Reshetova G. V.
Published: April 2024

One of the possible mechanisms causing significant emissions of methane into the atmosphere within the Arctic shelf may be the decomposition of gas hydrates. Their accumulations within the Arctic shelf formed almost simultaneously with the formation of permafrost, which contributed to the emergence of a zone of stable existence of gas hydrates. The subsequent flooding of the Arctic shelf led to the degradation of the permafrost and the violation of the conditions for the existence of hydrates. To assess the state of the stability zone, methods of mathematical numerical modeling are used. Standard seismic methods are widely used to localize gas hydrates, but monitoring their physical state requires the development of fundamentally new approaches based on solving multiparameter inverse seismic problems. In particular, the degree of attenuation of seismic energy is one of the objective parameters for assessing the consolidation of gas hydrates: the closer they are to the beginning of decomposition, the higher the attenuation, and hence the lower the quality factor. Thus, the methods of seismic monitoring of the state of gas hydrates in order to predict the possibility of developing dangerous scenarios should be based on solving a multi-parameter inverse seismic problem. This publication is devoted to the presentation of this approach.
A SAUROPOD FROM THE LATE CRETACEOUS OF AMUR OBLAST
Authors: Averianov A. O. , Bolotsky Yu. L. , Bolotsky I. Yu.
Published: April 2024

A narrow-crowned sauropod tooth from the Udurchukan Formation (Maastrichtian) at Blagoveshchensk locality (Amur oblast, Russia) is morphologically identical with the teeth of Nemegtosaurus from the Nemegt Formation (Maatsrichtian) Mongolia and can be referred to the titanosaurs of the family Opisthocelicaudiidae. This tooth is the only sauropod find from the Late Cretaceous of Russia.
UNPRECEDENTED DURATION OF THE 2020 ANTARCTIC OZONE DEPLETION
Authors: Zuev V. V. , Savelieva E. S. , Pavlinsky A. V. , Sidorovski E. A.
Published: April 2024

In this work, we show a trend of lengthening the period of high intensity of the Antarctic polar vortex in late spring and early summer (November–December), which has been traced over the past 30 years. This trend is observed both in the dynamics of the main characteristics of the polar vortex (vortex area and wind speed along the vortex edge) and in the Antarctic ozone hole area. A clear manifestation of this is the polar vortex dynamics in 2020, when there were unusually high wind speeds along the vortex edge throughout the entire period of its existence and record values of vortex area and ozone hole area from mid-November to December. In addition, the polar vortex existed until the last week of December, which is an unprecedented case. To analyze the Antarctic polar vortex dynamics, we used the vortex delineation method by geopotential values determined from the maximum temperature gradient and maximum wind speed characterizing the vortex edge.
EFFECT OF SULFUR CONCENTRATION ON OLIVINE SULFIDATION UNDER LITHOSPHERIC MANTLE PT-PARAMETERS
Authors: Bataleva Y. V. , Furman O. V. , Zdrokov E. V. , Borzdov Y. M. , Palyanov Y. N.
Published: April 2024

Experimental studies aimed at the modeling of interaction processes of sulfur-bearing metasomatic agents with mantle silicates and assessing the effect of sulfur concentration on olivine sulfidation were carried out in the Fe,Ni-olivine – sulfur system using the high-pressure multi-anvil apparatus BARS (1050 and 1450°C, 6.3 GPa, 40–60 hours, sulfur concentrations (Xs) 0.1, 2 and 6 mol. %.). It has been established that as a result of the recrystallization of Fe,Ni-olivine in a sulfur melt, Fe and Ni are extracted from olivine into this melt, and formation of Fe,Ni-sulfides (or sulfide melts) and low-iron, low-nickel silicates takes place. The key indicator characteristics of the olivine sulfidation process are determined depending on the temperature and sulfur concentration, including characteristic phase assemblages, regularities in the evolution of the chemical compositions of mineral and melt phases, and structural features of olivine crystals. It has been experimentally established that reducing sulfur-bearing metasomatic agents, even in minimal concentrations and at relatively low temperatures, are capable of dissolving and transporting mantle silicates and sulfides, and can play an important role in sulfide ore formation in the mantle.
TRANSFORMATION OF THE MALACOLOGICAL FAUNA OF THE SEA OF AZOV IN THE HOLOCENE AND ITS ROLE IN THE FORMATION OF COASTAL SPITS
Authors: Matishov G. G. , Kovalenko E. P. , Titov V. V.
Published: April 2024

The study and analysis of malacofauna from cores of bottom sediments and cores from the Azov spits showed the nature of the change during the transition from the Ancient Azovian to the New Azovian layers, the uneven distribution of communities in time and space. The shell material from littoral malacocenosis and shallow-water banks is the main component for the formation of spits. Based on a series of cores up to 25 m thick from the Dolgaya Spit, it is shown that its formation began about 2500 years ago, and carbonate material reflects the history of the development of the benthic fauna of the sea.
AGE OF ORE-BEARING IRON-MAGNEZIAN METASOMATITES OF THE CENTRAL PART OF THE ALDAN SHIELD: RESULTS OF U–PB (ID-TIMS) GEOCHRONOLOGICAL STUDIES OF GARNET
Authors: Stifeeva M. V. , Salnikova E. B. , Kotov A. B. , Gritsenko Y. D. , Peycheva I.
Published: April 2024

U–Pb (ID-TIMS) geochronological studies of garnet from iron-magnesian metasomatites of the ore occurrence of the Kurung-Hoonku River area (Legliera group of deposits, West Aldan megablock) were carried out. The results obtained (1901 ± 5 MA) are first age determination of formation ore-bearing iron-magnesian metasomatites on the Aldan shield. It show their connection with the final stages of the Early Proterozoic tectonic-magmatic evolution of the Aldan geoblock.
STUDY OF SEASONAL AND LONG-TERM CHLOROPHYLL VARIABILITY IN THE CASPIAN SEA BASED ON REMOTE SENSING DATA
Authors: Vostokov S. V. , Saling I. V. , Vostokova A. S. , Gadgiev A. A. , Lobachev E. N. , Abtahi B. , Shojaei M. G.
Published: April 2024

The patterns of seasonal and long-term variability of phytoplankton in the Caspian Sea have been studied using SeaWiFS and MODIS-Aqua scanners. Chlorophyll “a” concentration (CHL) in the Caspian Sea were calculated by the regional algorithm developed using an array of in situ measurements in different seasons of the year. Maps of the average monthly CHL values over a twenty-two-year period and seasonal variability diagrams were constructed for the Northern, Middle and Southern Caspian Sea. The features of seasonal variability of phytoplankton are analyzed using CHL data. The fundamental differences were mentioned in seasonal variability of phytoplankton in the Northern, Caspian Middle and Southern Caspian. The regularities of the spatial dynamics of CHL throughout the Sea, resulting from seasonal succession of phytoplankton have been studied. The years with significant deviations of the seasonal dynamics of CHL from the average climatic one was identified.
U–PB (ID-TIMS) AGE OF GARNET FROM AILLIKITES OF KOLA ALKALINE PROVINCE
Authors: Stifeeva M. V. , Salnikova E. B. , Nosova A. A. , Kotov A. B. , Vozniak A. A. , Dimitrova D. A.
Published: April 2024

U–Pb (ID-TIMS) geochronological studies of garnet from aillikites of the Kandalaksha dyke swarm (Kola alkaline province) were carried out. The obtained estimate of the U–Pb age of the garnet (374 ± 3 MA) coincides with the interval (373–377 MA) of the main stage of alkaline magmatism of the Kola province (LIP). This allows us to conclude that the formation of rocks of the dike complex of the Kandalaksha Bay and rocks of the phoidolite series of alkaline-ultrabasic massifs of this province is synchronous.
METAMORPHISM OF UNI SUITE AS AN INDICATOR OF EARLY PRECAMBRIAN COLLISION PROCESSES IN THE VYATKA BELT, BASEMENT OF THE VOLGA-URALIA
Authors: Pilitsyna T. A. , Erofeeva K. G. , Samsonov A. V. , Postnikov A. V. , Varlamov D. A.
Published: April 2024

In the central part of the Vyatka belt, sandwiched between the Archean blocks in the northeast of the Volga-Ural segment of the East European craton, according to the core data from two deep wells, the following mineral parageneses were established in the metapelites of the Uni suite: (1) Pl + Ms + Bt + Qz + Kfs + And ± Chl and (2) Pl + Bt + Qz + Kfs + Grt + Sil ± Ms ± Chl (without staurolite and cordierite), corresponding to moderate pressure metamorphism of the amphibolite facies. To determine the P-T conditions for these parageneses a set of methods was used, including classical (Grt-Bt, GASP, Ti-in-Bt, Ms-Bt) and multi-equilibrium thermobarometry (winTWQ 2.34), as well as the isopleth intersection method on pseudosection diagrams (GeoPS 3.2.2.128). The calculated P-T values of metamorphism are 520–650°C (or up to 690°C according to the isopleth method) and 2–5.4 kbar. Paragenesis (2) rock was accompanied by anatexis in the water-saturated system. Zoning can be distinguished in the metamorphism of the rocks, it belongs to a relatively shallow type, to the andalusite-sillimanite subfacies.
NEW DATA ON THE PATTERNS OF METHANE DISTRIBUTION OVER THE ARCTIC SHELF OF EURASIA
Authors: Shakirov R. B. , Khazanova E. S. , Stepochkin I. E.
Published: April 2024

New results of the analysis of methane distribution in the troposphere over the Arctic shelf of Eurasia using satellite methods are presented. The main trends in the variability of methane content (increase), temperature (fluctuations without a pronounced trend) and ice cover for the period 2010–2022 are shown. Conclusions are made about the difference in the distributions of atmospheric methane over the western and eastern Eurasian Arctic, divided by the zone of the seismically active lineament of the Gakkel Ridge. It is shown that hydrometeorological parameters, including temperature and ice formation, are probably not the main factors for increasing the methane content in the atmosphere of the Eurasian Arctic shelf. The increase in methane content is associated with regional factors that are widespread over vast areas, such are, first of all, geological structures: oil and gas basins and tectonic fragmentation of the lithosphere, which forms permeability zones.
IRREGULARITIES THE RELATIONSHIP OF VARIATIONS IN THE VOLUME ACTIVITY OF RADON AND ATMOSPHERIC PRESSURE DURING SEISMIC ACTIVITY (ON THE EXAMPLE OF THE BAIKAL REGION)
Authors: Seminsky K. Zh. , Bobrov А. А.
Published: April 2024

A comparison was made of temporal variations in atmospheric pressure and soil radon concentration measured in loose sediments at three monitoring stations in the Baikal region for the period of manifestation of three fairly strong earthquakes – Bystrinsky (21.09.2020, K = 14.6), Kudarinsky (09.12.2020, K = 14.0) and Khubsugulsky (11.01.2021, K = 16.0). It has been established that the release of radon is controlled in the region by variations of atmospheric pressure. Irregularities of this dependence, first identified in the course of a formalized statistical analysis, occur for each of the studied seismic activations. They are connected with the process of preparing an earthquake, which opens up real opportunities for developing an emanation approach to medium-term forecasting.
COMPARISON OF THE I AND IV DIAMOND TYPES (ACCORDING TO THE CLASSIFICATION OF Y.L. ORLOV) FROM THE SNAP LAKE KIMBERLITES (SLAVE CRATON, CANADA)
Authors: Ivanova O. A. , Pokhilenko N. P. , Afanasiev V. P. , Zedgenizov D. A. , Barabash E. O.
Published: April 2024

The article is devoted to the study of diamonds of the I and IV varieties (according to the classification of Y.L. Orlov) from Snap Lake kimberlites. Based on the study of the morphology, the impurity defects of nitrogen and the internal structure of these diamonds, it was found that the uncoated crystals and the cores of coated diamonds were formed under similar conditions. It is assumed that the coats were formed on a significant part of the formed diamonds under mantle conditions, and their etching occurred at the hypogenic stage of the development of the kimberlite body.
DIRECTIONALITY AND PHASING OF CABONATE ACCUMULATION IN THE EARTH HISTORY
Authors: Kuznetsov V. G.
Published: April 2024

In the geological history of the Earth, there has been a significant change in the composition and areas of formation of carbonate deposits, which reflects the general evolution of methods, paleogeographic and geochemical settings during this time, and different stages in this evolution. At the Archean-Proterozoic boundary, acidic conditions in impounded bodies changed to moderately acidic, which is seen in the appearance of iron carbonates. The second frontier is the Siderian-Rhyacian boundary, when intensive assimilation of CO2 led to the formation of alkaline conditions in impounded bodies and the accumulation of magnesian carbonates. Carbonate accumulation itself occurred in the impounded bodies of continental block. The third milestone is the Vendian-Cambrian boundary, when skeletal fauna appeared, and carbonate accumulation became largely biogenic. Along with the basins of the continental block, there were new oceanic areas of formation of carbonate sediments, where the skeletons of nekton organisms became a significant supplier of material. The fourth boundary – Paleozoic-Mesozoic one – was the beginning of the accumulation of the proper oceanic deep-water carbonate sediments. The fifth milestone is associated with the Cretaceous period, when oceanic carbonate accumulation sharply increased due to planktonic organisms.
A NEW COMBINED TECHNIQUE FOR SOLVING NONLINEAR GRAVITY PROBLEMS FROM PLANETARY TOPOGRAPHY, GRAVITY FIELD DATA AND CRUSTAL THICKNESS WITH THE USE OF THROWING OFF ALGORITHM
Authors: Salnikov A. M. , Stepanova I. E. , Gudkova T. V. , Batov A. V. , Shchepetilov A. V.
Published: April 2024

We test a new combined technique of solving nonlinear gravity problems using three types of datasets: gravity field, topography and crustal thickness in the Elysium Planitia region on Mars.
SERIES OF CATASTROPHIC EARTHQUAKES IN TURKEY 06.02.2023 AND PERTURBATION OF GEOPHYSICAL FIELDS
Authors: Adushkin V. V. , Spivak A. A. , Rybnov Yu. S. , Tikhonova A. V.
Published: April 2024

An analysis of variations in the microbaric background, magnetic and electric fields in the surface layer of the atmosphere, accompanying strong earthquakes on February 6, 2023 in Turkey, is presented. The analysis involved the results of instrumental observations performed at the Center for Geophysical Monitoring of Moscow and the Mikhnevo observatory of the IDG RAS, as well as data obtained by a number of magnetic observatories of the INTERNAGNET network. It is shown that, in addition to the seismic effect, earthquakes were accompanied by variations in the magnetic and electric fields, as well as the generation of infrasonic waves recorded at a considerable distance from the sources.
FIRST EVIDENCE FOR THE PRESENCE OF THE UPPER CARBONIFEROUS DEPOSITS ON THE TUORA-SIS UPLIFT OF THE LOWER REACHES OF THE LENA RIVER, NORTHEAST RUSSIA
Authors: Makoshin V. I. , Kutygin R. V.
Published: April 2024

A vertical sequence of brachiopods was revealed at the base of the Verkhoyanian terrigenous complex of the Tit-Ary section in the northern part of the Tuorasis uplift of the lower reaches of the Lena River. As a result of the study of these brachiopods, it was established that in the indicated section, the Upper Cambrian dolomites are overlain by Gzhelian and Asselian deposits, characterized by brachiopods of the Jakutoproductus protoverkhoyanicus and Jakutoproductus verkhoyanicus biostratigraphic zones. This is the first proven fact of the presence of Upper Carboniferous deposits in the area. It is concluded that within the Tuorasis uplift from south to north, the upper age limit of the unconformity between the Cambrian and the Upper Paleozoic is growing older, while the base of the Verkhoyanian terrigenous complex is built up by the Permian basal beds and the Gzhelian deposits of the Upper Pennsylvanian. The Tit-Ary section is the first of those established in the lower reaches of the Lena River, with exposed boundary Carboniferous-Permian beds.
ECOLOGICAL RESOURCES OF BOREAL FORESTS IN ABSORPTION OF GREENHOUSE GASES AND IN ADAPTATION TO GLOBAL WARMING (TO THE PARIS AGREEMENT ON CLIMATE CHANGE)
Authors: Kotlyakov V. M. , Kolomyts E. G. , Sharaya L. S.
Published: April 2024

On the example of the forests of the Oka basin, an experiment was carried out to numerically solve the dual task set by the Paris (2015) Agreement on climate change: to assess the absorption of CO2 from the atmosphere by forest communities under current global warming and their adaptation to climate change. With the help of empirical-statistical modeling, the mechanisms of forest cover regulation of the carbon cycle are revealed, with the effect of mitigating the predicted warming. Assessments of the adaptive potential of forests and its role in carbon adsorption and conservation have been carried out. The proposed index of elastic-plastic functional stability of forest ecosystems was used as an indicator of adaptation. The role of forest sustainability as a direct environmental factor in the absorption of greenhouse gases has been statistically established. An unambiguous picture of a significant increase in the ecological resources of boreal and nemoral forests has been obtained – their adsorption capacity with an increase in adaptive potential. It has been established that during the predicted 100-year period, the overall elastic-plastic stability of forest formations in the region should increase, especially at the current rate of global warming. Due to this, a significant increase in the ability of boreal and, to a lesser extent, nemoral forests to absorb greenhouse gases should also be expected. The obtained results of regional predictive modeling demonstrate the effectiveness of the coupled study of the adsorption capacity of forest biomes and their adaptation to a changing climate.
DEFICIENCY OF RARE-EARTH ELEMENTS IN NATURAL LANDSCAPE COMPONENTS AS A CAUSE OF GEOPHYGY AMONG UNGULATES ON OLKHON ISLAND
Authors: Panichev A. M. , Baranovskaya N. V. , Chekryzhov I. Ju. , Seryodkin I. V. , Ivanov V. V. , Vakh E. A. , Elovskiy E. V.
Published: April 2024

The actuality of the work lies in the systematic study of the causes of geophagy from the viewpoint of the rare earth hypothesis. From the original results of complex geological-hydrobiogeochemical studies carried out on Olkhon Island (Lake Baikal). ), it follows that the phenomenon of geophagy among wild and domestic ungulates on the island is due to a deficiency of light rare earth elements (LREE) in plant foods and natural waters. The deficit is associated with a low concentration of LREE in the composition of the most common metamorphic terrigenous-carbonate rocks, deluvium and soils on the island. The similar geochemical specificity of landscapes can be the cause of LREE imbalance in the hormonal system of the body. Hormonal stress causes animals to regularly and periodically consume kaolinite clays of weathering rocks enriched with the necessary elements.
AGE AND STRATIGRAPHIC POSITION OF THE SUPRACRUSTAL COMPLEX (THE KASKAMA BLOCK, INARI TERRANE, NORTH-EAST KOLA-NORWEGIAN REGION OF THE FENNOSCANDIAN SHIELD)
Authors: Vrevsky A. B. , Kuznetsov A. B. , Lvov P. A.
Published: April 2024

New data of U-Th-Pb age (SIMS) of magmatic (T = 730–744°C) zircon from intermediate and acid metavolcanics (1923–1926 Ma) of the supracrustal complex in the Kaskama block of the Inari terrane (north-west of the Kola-Norwegian region of the Fennoscandian shield) were obtained, which makes it possible to attribute them to the Kalevian suprahorizon. The source of primary melts of metariodacites and metabasaltes in the Kaskama block was the paleoproterozoic continental lithosphere not younger than 2390–2384 Ma. It is shown that the age of the tonalites of the Kuroaivi massif (1936 ± 7 Ma, εNd(T) = +0.1) as well as the granitoid massifs of the Southern Pechenga zone (1950–1940 Ma), are older, within the errors of U-Th-Pb age determinations, than the volcano-sedimentary rocks of the Kaskama unit and the Vepsian of the Southern Pechenga zone. This period of granite formation separates the early geodynamic stages of the continental rifting at the Yatulian-Ludikovian time from regimes, similar to the suprasubductional formation of the continental lithosphere, of the Inari terrane (1926–1850 Ma).
NEW DATA ON GEOLOGY AND PALAEOGEOGRAPHICAL EVOLUTION OF THE SOUTHERN EAST SIBERIAN SEA
Authors: Petrov O. V. , Ryabchuk D. V. , Sergeev A. Yu. , Budanov L. M. , Zhamoida V. A. , Neevin I. A. , Taldenkova E. E. , Prishchepenko D. V. , Nosevich E. S. , Pushina Z. V. , Grigoriev A. G. , Bashirova L. D. , Ponomarenko E.P.
Published: April 2024

The paper deals with the results of geological and geophysical research of shallow-water areas of the East Siberian Sea, started in 2018 in the frame of State Geological Mapping project (Geological Map of 1 : 1 000 000 scale) and continued in 2022 under support of the Russian Science Foundation project. The seismostratigraphic scheme of the Quaternary sediment sequence is compiled, and the conception of the palaeogeographical evolution in the Late Pleistocene-Holocene is proposed.
THE OLDEST TRACE FOSSILS IN ASSOCIATION WITH EDIACARA-TYPE BIOTA IN THE UPPER VENDIAN OF THE SOUTH URALS
Authors: Kolesnikov A. V. , Desiatkin V. D. , Terekhova V. A. , Pan’kov V. N. , Maslov A. V.
Published: April 2024

Trace fossils and palaeopascichnids have been studied from the Basa Formation of the Vendian Asha Group of the South Urals (southwestern periphery of the Suleiman Anticline, Shubino quarry in the Ust’-Katav city, Chelyabinsk Region. The general morphology and preservation of ichnofossils was shown to be similar to the Late Vendian-Early Cambrian subhorizontal bilobate burrows of Didymaulichnus. The paleontological remains were found to be confined to extremely shallow depositional settings and located stratigraphically below the volcanic tuff layer, the zircon from which has a U–Pb isotopic age of 578 ± 7 Ma. Until now, the first occurrence of trace fossils and the associated “Agronomic Revolution” were thought to be timed to the interval of ~560–550 Ma. Our results show that mobile benthos and biological mixing of sediments may have occurred 20–30 Ma earlier and support the hypothesis that the onset of the first “Agronomic Revolution” and the “Cambrian Explosion” were not significantly coincident in time.
A LONG-LASTING EVOLUTION OF THE ORE-MAGMATIC SYSTEM AT THE MURUNTAU GOLD DEPOSIT (WESTERN UZBEKISTAN, TIEN SHAN): THE EVIDENCE FROM ISOTOPIC U-PB ZIRCON AGE (LA-ICP-MS METHOD) OF THE GRANITOIDS OF THE SARDARA (SARYKTY) PLUTON
Authors: Soloviev S. G. , Kryazhev S. G. , Semenova D. V. , Kalinin Y. A. , Bortnikov N. S.
Published: April 2024

The paper presents the first data of the isotopic zircon U–Pb study (LA–ICP–MS method) on the granodiorite-granite from the Sardara (Sarykty) pluton in the district of the giant Muruntau Au deposit in the Western Tien Shan (Uzbekistan). In a single sample, three age groups of zircon crystals identified, with their concordant U–Pb age being 322.0 ± 3.7 Ma (MSWD = 3.1, 4 zircon grains), 301.6 ± 2.1 Ma (MSWD = 0.17, 11 zircon grains), and 289.1 ± 4.9 Ma (MSWD = 0.98, 2 zircon grains), respectively. The scatter of the isotope age data obtained can be interpreted using the model of subsequent crystallization of various zircon generations in variably-deep magmatic batches, followed by zircon capturing during the magma differentiation and crystallization. Notable is a quite close coincidence of the two (the younger) age intervals to the concordant U–Pb zircon ages, which were published before for the granitoid rocks found directly at the Muruntau deposit. The latter thus can represent the dike “splits” occurred at the respective stages of the magma evolution (progressing differentiation) in the deeper batches of the granitoid magma, with its larger intrusions represented by the Sardara (Sarykty) and other plutons outcropping at some distance from the deposit. Overall, the older isotopic U–Pb zircon data of the Sardara (Sarykty) pluton (in the order of 322 Ма and 302 Ма, respectively) correspond closer to the subduction event, whereas the younger U–Pb zircon data (in the order of 289.5 Ma) are quite relevant to the post-collisional stage occurred in the region. Therefore, the initiation and initial development of the magma batches in the Muruntau deposit district could occur in the subduction environment but the final granitoid magma differentiation and crystallization were completed already at the post-collisional stage.
FIRST RESULTS OF U−Th/He DATING OF EPIGENETIC PYRITE FROM ROCKS OF THE BAZHENOV FORMATION, WESTERN SIBERIA
Authors: Yakubovich O. V. , Vasilyeva N. A. , Vasilyeva K. Yu. , Anosova M. O. , Kotov A. B. , Podolskaya M. M. , Gorokhovskiy B. M.
Published: April 2024

U–Th/He method was applied to determine the age of epigenetic pyrite from the oil source rocks of the Bazhenov Formation, Western Siberia. Results indicate the possibility to date the post-sedimentation processes in a sedimentary basin by authigenic pyrite U–Th/He dating. The U–Th/He isochron age of pyrite (n = 7) from the dolomites of the Bazhenov Formation within the Frolovskaya megadepression is much younger than the age of sedimentation and corresponds to the Santonian-Cenomanian stages of the Upper Cretaceous (90 ± 8 Ma).
FIRST DISCOVERY OF AUTHIGENIC CARBONATES ON THE LAPTEV SEA FLANK OF THE GAKKEL RIDGE (ARCTIC OCEAN)
Authors: Kaminsky D. V. , Chamov N. P. , Krylov A. A. , Neevin I. A. , Bujakaite M. I. , Degtyarev K. E. , Dubensky A. S. , Kaminsky V. D. , Logvina E. A. , Okina O. I. , Semenov P. B. , Kiel A. O. , Petrov O. V. , Pokrovsky B. G. , Tolmacheva T. Yu.
Published: April 2024

The article describes the first find of authigenic carbonates on the southern flank of the Gakkel Ridge in the zone of its junction with the Laptev Sea continental margin of the Russian Federation. The samples are represented by dense magnesian calcites and aragonites, including rounded and angular fragments of terrigenous material, as well as microphytoplankton of different ages, spores and pollen of terrestrial and aquatic plants. Elemental and organochemical characteristics indicate the predominance of oxidizing or intermediate between oxidizing and reducing conditions of carbonate crystallization, which may be a consequence of their formation near the bottom surface. The isotopic composition of O, C, and Sr allows us to conclude that the diagenetic carbonates of the Gakkel Ridge were deposited mainly in isotopic equilibrium with bottom water at a temperature of about 0°C, which corresponds to measurements from the ship. A wide range of δ13С (–23.5 до –37.3) indicates that methane was an important, but not the only source of carbon in carbonates. The wide variations in the 87Sr/86Sr (0.70906–0.70933), which correlate with the δ13С values, show that the carbonate-forming fluid was not only modern sea water, but also diagenetic solutions coming from the sedimentary cover together with methane and the products of methane and organic matter oxidation. Intense discharge of heterogeneous methane-bearing fluids may be related to the high modern tectonic activity of the studied region.