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The article summarizes published and new geological, geochronological, biogeographical, paleomagnetic, and petrological-geochemical data to support the tectonic zoning of the Central Asian Fold Belt (CAFB) and its Vendian-Paleozoic geodynamic evolution as a complex folded structure consisting of deformed fragments of collisional and accretionary orogens. It has been shown that the Central Asian-Siberian Platform was formed in the zone of junction of the collisional and accretionary margins of the Siberian craton, similar to the modern tectonic interactions between the Indo-Atlantic and Pacific global tectonic segments of the Earth and Eurasia. It has been shown that in the Vendian and Early Ordovician, there were two active margins around the Siberian craton: the collisional Tuvo-Mongolian margin and the accretionary Kuznetsk-Altai margin, which separated the craton from the tectonic plates of the Paleo-Asian Ocean (Indo-Atlantic segment) and the Paleo-Pacific Ocean (Pacific segment), respectively.A distinctive feature of the Paleoasiatic Ocean plate is complex structure, which includes fragments of oceanic crust and Precambrian Gondwana microcontinents with fragments of the Grenville orogeny. Fragmentary Grenville zircons (1.3-0.9 billion years old) are widely found in the Vendian-Paleozoic sedimentary deposits of various geodynamic settings of the collisional orogen. A distinctive feature of the accretion orogen is the widespread presence of oceanic crust fragments and the absence of Precambrian blocks of Gondwana, and as a result, the absence of Granville-age clastic zircons in the Vendian-Paleozoic sedimentary rocks of various geodynamic settings. The Early-to-Middle Paleozoic Charysh-Terekta-Ulagan-Sayan-Olkhon suture-shear zone separates the collisional orogen from the shelf of the back arc basin located in the northern part of the Altai-Sayan folded region framed by the Siberian craton. The suture-shear zone consists of fragments of the Vendian-Early Paleozoic oceanic crust of the Back Arc basin, Ordovician blue shales and Ordovician-Silurian turbidites, Late Silurian-Devonian collisional metamorphic rocks and granites. Based on the structural position of the suture-shear zone and the data of petrological and geochronological studies, it is concluded that it is a subduction-collision complex formed at the site of the back-arc basin of the Vendian-Cambrian Tuva-Mongolian island arc. Late Paleozoic shifts and thrusts manifested themselves in the CAFB in the Late Devonian-Early Carboniferous as a result of the collision of the Kazakhstan-Baikal orogen (composite continent) with the Siberian craton with the formation of the North Asian continent, and in the Late Carboniferous-Triassic as a result of the collision of the East European and North Asian continents. As a result of collisional events, the initially linear structures of the collisional and accretionary orogens were deformed into large oroclinal folds, divided by shifts and thrusts into many fragments, where the Vendian-Paleozoic structures are complicated by thrust-fold deformations.

The results of magnetic survey investigations conducted in the floodplain areas of the Yellow and Black rivers in the Lori Region of Armenia (northern part of the Republic of Armenia) are presented. Based on field observations, digital and graphical maps of the anomalous magnetic field (∆Ta) and its three-dimensional model were constructed. Analysis of the anomalous magnetic field structure made it possible to identify a number of positive and negative anomalous zones associated with geological formations differing in magnetic properties. It has been shown that the positive anomalies are caused by the presence of ultrabasic rocks (peridotites, pyroxenites) exposed along the left bank of the Yellow River and the right bank of the Black River. An extensive negative anomaly zone has been identified and interpreted as a reflection of a tectonic fault zone and the adjacent thick area of hydrothermally altered rocks. Comparison with the data on the physical properties of rocks confirmed the high contrast of magnetic characteristics between the ultrabasic and ore-hosting rocks.

The article presents algorithms for numerical modeling of electrical micrologging signals and calculation results in geoelectric models of impermeable rocks and the borehole environment of a porous, permeable reservoir. This research may be useful for developing an integrated approach to the quantitative interpretation of electrical logging data. A joint numerical analysis of electrical logs measured by conventional probes and microprobes will enable refining the radial electrical resistivity distribution in the borehole environment of oil-gas reservoirs. This, in turn, will provide additional information when jointly solving the problem of drilling mud filtration and numerical inversion of electrical logging data, resulting in a more accurate assessment of reservoir porosity and permeability. We have developed software for numerical simulation of electrical micrologging signals – those from a microgradient, micropotential and microlaterolog probe with focusing. We employ a finite element algorithm with an arbitrary position of the probes in a cylindrically-layered geoelectric model, and a finite difference algorithm for a microgradient and micropotential probe in a horizontally-layered model. Test calculations of the signals in geoelectric models of Western Siberia terrigenous deposits are presented. The models describe impermeable sediments as well as layers with the mud cake and invaded zone at different resistivity ratios. The model parameters correspond to Lower Cretaceous oil-gas reservoirs exposed with polymer-clay drilling muds. The analysis of the calculated micrologging signals reflects a small investigation depth of microgradient and micropotential probes, and a strong dependence of the signals on the drilling mud and mud cake resistivities. Numerical modeling in the class of a cylindrically-layered model has allowed us to obtain the radial resistivity change in the borehole environment of an oil-gas reservoir.

Experimental researches focusing on modeling of interaction between eclogitic and lherzolitic garnets with reduced and oxidized sulfur-rich fluids are conducted using multianvil high-pressure apparatus of “split-sphere” type (BARS). Experiments are carried out in garnet-sulfur-carbon and garnet-anhydrite-carbon systems at the pressure of 6.3 GPa and the temperatures of 1150, 1300, and 1450 °С in graphite ampules, as well as in Pt-ampules with hematite buffering container. It is experimentally demonstrated that interaction of both reduced and oxidized sulfur-rich fluids with mantle garnets leads to their partial dissolution and recrystallization, and to the formation of zoned crystals with decreased iron content in rims. Apart from that, this interaction also results in (1) garnet carbonatisation accompanied by formation of the magnesite±dolomite+kyanite+coesite assemblage, and (2) garnet sulfidation with formation of pyrite (1150-1300 °С) or sulfide melt (1450 °С) as inclusions in garnets and in interstitial space. As a result of conducted experimental researches it is established that indicatory characteristics of mantle garnets that underwent metasomatism by sulfur-rich agents, are decreased FeO content in peripheral crystal zones relatively to their centers, and formation of sulfide inclusion in the zones borders. In this paper we also present the first data on diamond dissolution in the silicate-sulfur-carbon systems under lithospheric mantle P,T-parameters that simulate mantle metasomatism of garnet-bearing lithologies by sulfur-rich fluids. It is found that under such conditions diamond crystals undergo partial dissolution resulting in formation of characteristic etching pits (negative trigons on {111} and rectangles on {100}).

Spectral decomposition is a widely used method of qualitative seismic interpretation, whose key limitation lies in the subjective selection of frequency components for visualization. Existing approaches based on the analysis of the integral Fourier spectrum do not account for the temporal localization of the signal’s spectral content. This study introduces a new method for the automatic selection of frequencies based on approximating local spectra obtained via the Short-Time Fourier Transform (STFT) with a sum of three Morlet wavelet spectra. This approach enables the extraction of time-dependent frequency trajectories that capture the evolution of the signal’s spectral content, rather than relying on a static set of frequencies over the entire interval. The optimization problem is solved using the differential evolution algorithm. The method was tested on data from fields of the West Siberian petroleum province. Quantitative evaluation using Shannon and Rényi entropy metrics, as well as a colorfulness metric, demonstrated increased informativeness of RGB images compared with traditional approaches. The proposed method reduces interpretation subjectivity and ensures reproducibility of results.

Experimental studies aimed at assessing the possibility of diamond crystallization during interactions of alkaline earth and transition metal carbonates with sulfur, as well as at characterizing the obtained diamond crystals and inclusions in them, were carried out on a multi-anvil high-pressure "split sphere" apparatus (BARS). The experiments were performed at constant P,T,t-parameters: 6.3 GPa, 1550 ºС and a duration of 20 hours, in the Mg,Ca-carbonate-sulfur system with different CaO/MgO ratios and Fe,Mg,Ca-carbonate-sulfur system with variable FeO/CaO/MgO proportions. It was experimentally established that in the alkaline earth carbonate-sulfur systems, a Ca,Mg-carbonate melt with dissolved sulfur (1.2-6.0 wt.%) is formed, which is a diamond growth medium. The stable growth form of diamond crystals is the octahedron, and an increase in the Ca# of the system is accompanied by an increase in the growth rate of the {111} faces. It was demonstrated that in the Fe,Mg,Ca-carbonate–sulfur system, the crystallization medium and the source of diamond carbon is the Fe,Mg,Ca-carbonate melt with dissolved sulfur, and diamond growth occurs as a result of the redox interaction of the sulfide and carbonate melts. With an increase in the ferruginousity of the system from 0.41 to 0.78, there occurs (1) an increase in the growth rate of the {100} faces (from 1.0 to 5.4 μm/h); (2) a change in the predominant elements of the octahedron face microrelief from triangular growth layers to hexagonal vicinals; and (3) an increase in the number and size of inclusions, as well as the evolution of their phase composition. Diamond inclusions are formed by melt preservation on the {100} faces during the transformation of a cuboctahedron into an octahedron. The inclusions contain quenched carbonate melt (quenching phases — carbonate, magnetite, and graphite), sulfur melt, and Fe-S-O melt. The discovery of a carbonate+magnetite+graphite association in the inclusions confirms the occurrence of a siderite redox dissociation reaction (3FeCO₃ = Fe₃O₄ + 3C⁰ + 2.5O₂ fluid) at the P,T-parameters of the lithospheric mantle. These results shed light on the possible origin of magnetite inclusions in upper-mantle diamonds and suggest that the presence of magnetite in syngenetic inclusions may be an indicator of the participation of iron-bearing carbonates in natural diamond formation processes. The results of the conducted studies indicate that Mg,Ca- or Fe,Mg,Ca-carbonate melts with dissolved sulfur can be classified as natural diamond-forming environments, and the identified features of the morphology of diamond crystals, the specifics of its growth and the composition of inclusions depending on the cationic composition of the carbonate melt with dissolved sulfur can be used as indicators of diamond crystallization in similar melts in nature.

This paper presents new evidence for fluorine enrichment in the diamond-forming mantle of the Siberian Craton. For the first time, we have discovered inclusions containing calcium and aluminum fluorides in diamonds from placers in the northeast of Siberia. In contrast to microinclusions in fibrous diamonds and coated diamonds, the inclusions we studied in diamonds from the northeastern Siberian Craton placers can be interpreted as fluoride melts. In diamond ISTD-119, inclusions are oriented parallel to the octahedron faces and can be considered syngenetic. At the same time, in diamond ISTD-124, an elongated inclusion is oriented parallel to slip lines. This provides grounds to believe that the formation of the inclusion was synchronous with the stage of diamond deformation. In variety V diamonds XLS-147 and ISTD-193, the morphology of inclusions located in the central parts of the crystals allows them to be interpreted as healed fractures. Within the inclusions, fluorine is present as compounds with calcium, having stoichiometry close to fluorite. The inclusions exhibit areas consisting of calcium fluorides and areas consisting of carbonates and/or iron oxides. In variety V diamond XLS-147, aluminosilicate inclusions and inclusions consisting of aluminosilicate and fluoride parts were identified. However, unlike inclusions in diamonds ISTD-119, ISTD-193, and ISTD-124, the fluoride part of the inclusions in diamond XLS-147 is represented by aluminum fluorides. There is a body of evidence for the growth of type V diamonds in a subduction zone. The compositional variations of the inclusions we studied indicate immiscibility of fluoride melts with aluminosilicate and carbonatite melts. The inclusions we have investigated testify to a fluorine-enriched diamond-forming mantle of the Siberian Craton at the time of diamond formation.

A thermodynamic model of the interaction between surface waters and the wastes of flotation enrichment of sulfide PGE–Cu–Ni ores from the ore region under consideration (Krasnoyarsk krai) is presented. The relevance of the study is determined by the need to assess the long-term stability of mineral associations. The aim of the work is to establish the patterns of transformation of mineral associations during long-term storage. The initial information was provided by mineralogical and chemical composition of samples from two pits, as well as the chemical composition of water extracts [Starostina et al., 2025]. Calculations were carried out in the solid–water–gas system under variations of Eh, simulating different degrees of system openness to atmospheric oxygen (standard T–P, pCO_2(gas) = 10^–3.5 atm). Based on the modeling results, it was found that pyrrhotite is stable under extremely reducing conditions (pO_2(gas) = 10^–79 atm), where the dissociation of water into atomic oxygen and hydrogen may occur. In general, the obtained models reflect the transition from sulfide to oxide–silicate associations with a decrease in the number of mineral phases as oxidation progresses. The modeled associations correspond well with mineral parageneses observed in polished sections. It was shown that the material retains its primary mineral structure even after decades of storage, which is explained by the high content of rock-forming minerals within a dense clay matrix that prevents oxygen and moisture from penetrating in amounts sufficient for intensive oxidation. The results obtained are recommended for use in the development of technological schemes for the recovery of potentially valuable metals from the flotation wastes of sulfide PGE–Cu–Ni ores.

The problems of mapping the relief of deep-sea surfaces are mainly associated with the impossibility of obtaining data on the geological structure of the discovered forms, which often makes it difficult to unambiguously determine their genesis. The paper provides examples of using additional information to increase the reliability of conclusions about the relief of the bottom surface of a deep-sea basin. To clarify the genesis of the bottom forms of the Baikal Basin, published data from seismic and geophysical studies of the bottom surface, and core drilling materials were widely used. As a result of the analysis of the obtained material, the genesis of the remnants on the underwater slope of South Baikal was established, and it was found that the sharp turns of the valleys of some canyons are explained by the lithological, structural and textural features of the slope deposits.

To study the adaptive capacity of crop production under changing climatic conditions, a database of spatiotemporal characteristics of hazardous and adverse natural-climatic events during the warm season has created at the Laboratory of Geoecology and Geosystem Dynamics at the Institute of Monitoring of Climatic and Ecological Systems the Siberian Branch of the Russian Academy, for the southern taiga of Western Siberia. The components of the database, its structural features, and its capabilities of spatial assessment and cartographic visualization of the studied phenomena which it allows are shown. Based on the analysis of meteorological data from 32 stations over the last 20-year period, a series of thematic and integrated maps illustrating the territorial and temporal patterns of hazardous and adverse natural-climatic events have been created within a GIS environment. Intra-regional patterns in the intensity, frequency, and duration of these events were identified. Statistical assessment and mapping have revealed that climate-induced risks to the local crop production system are not decreasing and that their spatiotemporal patterns are heterogeneous. The highest risks for plant growing occur during the spring season and are associated with the hazardous phenomenon of late spring frosts. During the summer, climatic hazards in the northeast of the region are associated with intensive precipitation, while in the southwestern they are caused by hot weather. It has been noted that adverse events occur more frequently than hazardous ones and, in combination, create a high risk-forming potential. A detailed analysis of the spatiotemporal characteristics of the studied phenomena and the cartographic visualization of the results enable monitoring of developing hazardous situations, risk forecasting, and the formulation of recommendations for minimizing losses in crop production.