Institute of Natural Resources

Understanding Earth's Archean crust and mantle is fundamental to reconstructing terrestrial geodynamic evolution. However, these ancient rocks have undergone extensive metamorphic and metasomatic events that may overprint primary lithological and structural features, posing challenges to the interpretation of their original composition. The Divinópolis Complex represents a long-lived, polygenetic magmatic–metamorphic block in the São Francisco Craton, poorly understood but with a large amount of exposed newly identified gneisses and granites. In this study, we present integrated fieldwork, geophysics and laser ablation inductively coupled plasma mass spectrometry U–Pb ages of zircon and monazite. The complex consists of gneiss and migmatite tonalite–trondhjemite–granodiorite (TTG) units intruded by monzogranite and syenogranite, revealing multiple magmatic episodes. Differentiation of tonalitic magma into the upper crust has generated a TTG crust at 2915–2860 Ma followed by another one from 2800 to 2760 Ma. After 2760 Ma extensive generation of granodiorites and granites from potassic shallow sources indicates crustal and mantle differentiation. The last potassic pulses occur between 2650 and 2610 Ma and mark the period of tectonic quiescence. The crust was reactivated at 2.06–2.04 Ga, mainly along deep shear zones between major blocks. These events share parallels with other cratons such as Kaapvaal, Yilgarn and North China in showing a transition from plume to plate-tectonic dominance.

Research subject. Mineralogical and geochemical features and formation conditions of the Bulan gold-sulfide-quartz ore occurrence of the Makarov ore cluster in the Western Sayan.Methods. A Linkam TMS-600 thermostage and Olympus BX 51 optical microscope were used to determine temperatures, compositions, and fluid salinities in inclusions of mineral- forming fluid in quartz of gold-sulfide-quartz veins (SUSU, Miass, analyst Natalia N. Ankusheva). The chemical composition of gold was determined by SEM Hitachi TM-1000 (TuvIENR SB RAS, Kyzyl, analyst Renat V. Kuzhuget).Results. The conducted mineralogical and geochemical studies determined that gold formation at the Bulan ore field was single-stage in the form of gold-sulfide-quartz veins and veins with pyrite, chalcopyrite, arsenopyrite, pyrrhotite, as well as rare isolations of galena, fahlore, gold, and electrum. The results of fluid inclusion study from gold-sulfide-quartz veins showed that they were formed in the temperature range 170–230°C due to a weakly to moderately saline (3.5–6.8 wt % NaCl eq.) magmatic fluid of the K-Na-Mg±Fe-chloride composition. The stable range of fluid salinity and the narrow range of δ18O indicate a single magmatic source and insignificant influence of host rocks and meteoric waters. Conclusions. According to mineralogical and geochemical features and PT parameters, the Bulan ore occurrence is similar to low-sulfide deposits of gold-sulfide-quartz berezite-listvenite formation.

Abstract—Remote sensing of the Earth is currently being used to measure nonthermal radiation. Here, powerful electromagnetic radiation of the atmosphere, initiated by cosmic rays, in the range from low frequencies to the gamma range, have recently been discovered. Of particular interest is the study of such radiation in the microwave range, where aerospace research technology is well developed. This paper presents the results of joint measurements of microwave and gamma radiation of the atmosphere during thunderstorms in the summer of 2022 in Transbaikalia. The purpose of the study is to search for relatively long-term (up to several minutes) electromagnetic radiation near a frequency of 22.2 GHz on the line of the rotational spectrum of water vapor molecules. It is assumed that such a feature may arise due to the appearance of avalanches of runaway electrons generated by cosmic rays. In this process, in addition to bremsstrahlung gamma radiation, the excitation of the gaseous medium occurs, which can cause its superradiance in the microwave range. In case of strong electrification in fields with intensity higher than 0.284 MV/m, a unique phenomenon may occur—a self-sustaining photonuclear reaction in the lower atmosphere in thunderclouds. During this process, the electromagnetic glow may last from units to tens of minutes. This study has revealed several episodes of an increase in radiation intensity in the microwave range, accompanied by gamma-ray pulses in the thunderstorm atmosphere. The glow detected in the experiment can be explained by local electric discharges with an increase in cloud electrification. Another explanation is the occurrence of a self-sustaining photonuclear reaction creating a large volume of excited gas. Ways to improve the microwave measurement technique for recording high-energy phenomena in the lower atmosphere at a large distance from the measuring equipment, where gamma rays are not recorded, using satellites are discussed.

Data on the breeding success of hybrids, collected during direct field observations, are principally important for understanding nature of the species isolating factors and future fate of the hybridogeneous populations. In the zone of secondary contact between Eurasian magpie Pica pica and Oriental magpie Pica serica, emerging right now, limited hybridization occurs, what has been shown in our reported data on nuclear single nucleotide polymorphisms (SNP). In the present work, we have analyzed composition of 119 nesting pairs and content of 89 nests in the hybridogeneous population of P. pica leucoptera × P. serica jankowskii in Eastern Mongolia, then in the recent contact zone in Eastern Transbaikalia (South Siberia) and the relatively pure populations of P. p. leucoptera in Central Transbaikalia and P. s. jankowskii in Northeast China. In the hybridogeneous population of Mongolia, significantly increased portion of nonviable clutches with all dead eggs was recorded, as well as a portion of partly dead clutches, compared with the data on the pure population of Central Transbaikalia. The egg mortality was found to be much less dramatic in the population of the Eastern Transbaikalia, where hybridization is less pronounced than in Mongolia. Several possible mechanisms of genetic incompatibilities breaking the reproductive barriers are discussed. The future fate of this magpie contact zone is considered, taking in account selection against hybridization which was revealed in this study. Among possible scenarios, reinforcement of prezygotic isolation may occur, i. e., in the species-specific calls. It is possible that a kind of mosaic hybrid zone with some features of tension zone will appear. Monitoring of the unique situation with the emerging zone of contact and hybridization of two young magpie species is needed, as a necessary addition to genomic studies.

An analysis of the correlations between the ash content of coal (Adср) and the content of ash-forming elements was carried out. Significant positive pairwise correlations were revealed in the accumulations of SiO2, Al2O3, TiO2 and each of them with ash content Adср (rcr0.05=0.23). In the group Fe2O3, MgO, CaO, a significant positive correlation is observed between the accumulations of only Fe2O3 and MgO, but each of them correlates negatively with Adср. A qualitative analysis of the distributions of petrochemical modules (GM, AM, ZhM, TM) of coal ash from the 2.2-Ulug seam of the Mezhegey deposit was carried out. Hydrolyzate destruction of the mineral matter of coal in 94% of the studied sample (n = 70) is represented by superhydrolysates (GMmin 2.07, GMmax 7.45), normohydrolysates (GMmin 0.86, GMmax 1.95), hypohydrolysates (GMmin 0.56, GMmax 0.84). A combined analysis of correlations between the ash content of coal (Adср) and the contents of ash-forming elements and petrochemical modules of ash made it possible to establish the origin of ash-forming elements - ash-carrier Fe is aquagenic, ash-carriers Al, Ti are allotigenic.

Subject. This article discusses the importance of entrepreneurship in increasing tax revenues, creating jobs, and saturating the market with goods. Objectives. The article aims to assess the impact of small and medium-sized businesses on the overall development of the Republic of Tuva's economy and analyze government measures to support business. Methods. For the study, I used a comparative analysis. Results. On the basis of the analysis, the article shows the changes in the number of small and medium-sized businesses and the self-employed in the Republic of Tuva for 2019–2024, and breaks down them by municipality, urban district, and type of activity in 2023. The Tuvinian small and medium-sized business covers a quarter of the able-bodied population of the Republic. The overall increase in the number of business entities in the Republic of Tuva was accompanied by an annual increase in tax revenues. Conclusions. The results of the study can be taken into account when developing programmes to improve the Republic of Tuva's economic capacities.

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Prospects for the development and use of Unmanned Aerial Vehicles (UAV) are shown.It has been established that the role of airplanes increases with their successful implementation in various fields of activity, and sometimes they pose a threat to human life.The functional diagram of the radio-electronic system of the quadcopter-type UAV was presented on the basis of the technical solutions studied for the creation of unmanned aerial vehicles, and the working principle was reviewed.A printed circuit board for the flight controller is designed based on the developed functional diagram.One of the main features is the use of modern electronic components available today.