The Earth’s deep-seated shells are characterized by different water contents. The main mechanism of water transfer from the Earth’s crust to the mantle is related with the subduction processes of the oceanic lithosphere. The mantle transition zone, due to its ability to accumulate water in nominally anhydrous minerals (wadsleyite and ringwoodite) is its most important reservoir, especially in comparison with the upper mantle. Upper mantle peridotite within subducting slabs inside the transition zone can preserve H₂O at great depths in compounds such as “alphabetic” DHMS phases. The composition of lower mantle peridotite includes 80 wt % Mg-perovskite (bridgmanite), 15 wt % ferropericlase, and 5 wt % Ca-perovskite (davemaoite). Among these minerals, the highest water content is allowed in Ca-perovskite, followed by Mg-perovskite and ferropericlase. Taking into account the huge mass of the Earth’s mantle, even the minimum amount of water concentrated in nominally anhydrous phases can exceed the amount of water in the modern hydrosphere several times, despite the degassing of the mantle as a result of volcanic activity, which occurred especially intensively during the first 500 million years of the planet’s formation. The structural characterization of minerals — possible accumulators of water in the conditions of deep geospheres is given.

The epicenters of earthquakes in the Severomuysky tunnel area were found to be confined to positive anomalies of three morphometric parameters of the relief (depth of vertical dissection, asymmetry and excess of heights), contoured by values, exceeding the median or the 3rd quartile. Processing these parameters with the fuzzy logic ү-operator and the equivalent gradation method showed that both algorithms are equally informative for identifying seismically active areas. It was found that seismic events are accompanied by an increase in the horizontal velocity of movement of the IRKJ and BADG GNSS points and occur mainly at a small distance from the Earth to the Moon and the Sun, which can be explained by the increased gravitational effect of the latter on the Earth's lithosphere. Thus, a spatial relationship between seismicity and relief and a temporal relationship with astronomical parameters and velocities of modern crustal movements was revealed.

Based on a comprehensive lithologic and geochemical analysis of sediments from the southern Sea of Okhotsk and the northwestern Pacific Ocean, the lithologic-facies zoning of the region was performed for the first time. Three facies areas were identified: the Kuril Basin, the Kuril-Kamchatka Deepwater Trough, and the Northwest Pacific Ocean, each of which is subdivided into two subareas with characteristic morphological and sedimentary features. Differences in the sources and composition of terrigenous and volcanic-terrigenous material, the degree of primary biological productivity, and the role of gravitational and hydrodynamic processes in the formation of bottom sediments were established. Single-factor dispersion analysis and mathematical statistics methods allowed us to identify stable geochemical indicators (Si/Al, Fe, Ti, Th) that distinguish lithologic-facial zones. The Kuril Basin turned out to be the most productive in terms of biogenic sedimentation and saturated with terrigenous material, while the greatest influence of volcanism was recorded in the Kuril-Kamchatka Trough. The Northwest Pacific Ocean is characterized by a weak supply of sedimentary material and the predominance of pelagic and hemipelagic sediments.

The results obtained confirm the significance of the geological and geochemical approach and methods of statistical analysis in facies zoning of modern marine basins.

The distribution and relationships between granulometric parameters (percentage of size fractions, mean particle diameter, sorting coefficients, kurtosis, and skewness) of surface bottom sediments from the Chaun Bay of the East Siberian Sea were investigated with multivariate statistical processing. Using correlation, dispersion and factor analyses, the spatial variability of facies conditions was found to be consistent with the geographic characteristics, the structure of the coastal zone of the studied area, as well as mechanical differentiation of sedimentary material. Univariate regression analysis was employed to reveal the relationships between sand, clay, water depth, and sorting coefficient, and to obtain the corresponding regression models. The coastal facies are represented by good-sorted sandy sediments, which accumulate under conditions of active hydrodynamic regime and influence of tidal currents. Conversely, at a distance from the coast, with increasing depth and weakening of hydrodynamics under the influence of bottom currents, poorly sorted clayey-silty and silty-clayey sediments with sandy material are spread in the coastal-marine facies.

Primary (non-metamorphosed) Cu-Ni sulphide ores of pyrrhotite composition contain intergrowths of sperrylite PtAs₂ and hollingworthite RhAsS metacrystals in the Norilsk and Baikal deposits. Pyrrhotite of these ores is enriched in Rh (up to 31 ppm g/t); it contains a noticeable impurity of Ru and arose during the subsolidus transformation of high-temperature sulphide solid solution Mss (an efflorescence of sulphide Fe-Cu-Ni melt). Norilsk ores contain a significant amount of sperrylite metacrystals, the latest of pneumatolytic (fluid-metasomatic) Pd, Pt, Au and Ag minerals. The composition of Norilsk sperrylite is usually close to PtAs₂. Small-sized sperrylite metacrystals contain up to 11 wt. % of Sb in ore zones with geversite PtSb₂, stibiopalladinite Pd₅Sb₂ and naldrettite Pd₂Sb abundance. An absence of sperrylite is the feature of low-sulphide ores of the hyperbasite-basite Yoko-Dovyren pluton (baikalides at Northern Baikal region), whereas single sperrylite metacrystals occur only in pluton contact zones near the series of hornfelsed pyrite-bearing black shales. Sperrylite is developed significantly in Cu-Ni sulphide ores of the Baikal deposit, located in the lower exo- and endocontact of the Yoko-Dovyren pluton at the boundary with hornfelsed pyrite-bearing black shales series. Sperrylite in pyrrhotite ores of the Norilsk and Baikal deposits is a product of interaction of As- and Pt-rich fluids with pyrrhotite. Obviously, these fluids extracted Rh (as well as Ru and Ir) from pyrrhotite solid solution. As a result, sperrylite and hollingworthite intergrowths occurred. Composition of the sperrylite from intergrows with hollingworthite is (Pt_0.985Rh_0.015)₁(As_1.965Se_0.035)₂ (Norilsk) and (Pt_0.985Rh_0.015)₁(As_1.935Sb_0.065)₂ (Baikal). Norilsk hollingworthite rich in platinum; its composition is (Rh_0.63Pt_0.22Ru_0.10Ir_0.04)_0.99As_1.01S_0.99Se_0.01. Baikal hollingworthite crystals are sectorial: some of the growth sectors contain platinum, their composition corresponds to (Rh_0.84Pt_0.05Ir_0.02Co_0.04N_i0.03Fe_0.02)_1.00 As_0.99S_1.00Se_0.01, whereas other growth sectors are poor in platinum — (Rh_0.85Ir_0.01Co_0.08Ni_0.04Fe_0.02)_1.00As_0.98S_1.00Se_0.02.

Bentonite clays are widely used in various industries, including in the disposal of radioactive waste as components of engineered barriers system. The paper highlights the results of experiments on the transformation of bentonites under the influence of model solutions of pore waters of a crystalline massif, as well as on interaction with other components of barriers (steel, concrete). The experimental and analytical work carried out made it possible to identify trends in bentonite transformations, and features of transformational changes in the structure of smectites during contact interactions with materials of engineered barriers system (steel and concrete). The results can be used to substantiate the long-term safety of the deep geological disposal of radioactive waste at the Yeniseisky site, Krasnoyarsk region.

The structure and characteristic features of ecological-geological systems of residential complexes of Belarus have been identified and analyzed for the first time. The main abiotic component of the structure of these ecological-geological system (EGS) is the urbolitotope, which forms the lithogenic basis of the ecosystem. It includes urbanized relief, technogenically modified and artificial soil massifs with paragenesis of engineering-geological processes developed within their boundaries, as well as technogenically modified geochemical and geophysical fields. The most important abiotic components of the EGS of residential complexes are also the urbohydrotope, characterized by technogenically modified hydrogeological conditions, the urboedaphotope, consisting of various types of urbozems, the urboatmotope, reflecting technogenic change and pollution of the atmospheric air of cities. Abiotic components of the EGS of residential complexes also include various urban engineering structures: residential and public buildings, various public utilities, urban public and private vehicles, road communications, etc. The main sources of technogenic transformation of natural components are urban engineering structures of various purposes associated with residential development of territories. It is shown that all components of the EGS of residential complexes, both abiotic and biotic, interact with each other and have a set of specific characteristics caused by the influence of urbanization and anthropogenesis, which must be taken into account in their taxonomy, description and analysis of ecological functions of the lithosphere. The revealed patterns and features of the EGS of residential complexes in Belarus can be considered as common for similar EGS in Russia, which must be taken into account in engineering and environmental studies and engineering and environmental surveys.

In engineering geology clay soils are investigated from different positions, including from the point of view of their spatial distribution. The latter is especially important for the vast territory of our country. Overview maps of the distribution of pre-Quaternary and Quaternary clay soils on the Russian territory are compiled. The regularities of their distribution by area and section within platform and mountain regions are described.

This paper presents the key characteristics of a digital broadband seismic network in the southern part of the Russian Far East. It is shown that over the past 20 years, there has been a qualitative leap in the instrumental capabilities of seismic observations in the region. The modern configuration of the network not only fulfills its primary purpose — monitoring regional seismicity — but also enables the study of structural features in the mantle transition zone (MTZ). Analysis of data from the “Gorny” (GRNR) station using P-receiver functions (PRF) revealed converted waves from the 410 km and 660 km discontinuities. The observed travel time anomalies can be explained either by seismic velocities lower than those predicted by the IASP91 reference model or by anomalous depths of the MTZ boundaries.

In high-resolution seismic surveys, source parameters — whether for single sources or source arrays — are often selected empirically or based on prior studies without proper regional adaptation. This approach is methodologically flawed and frequently results in reduced data quality and interpretability. Consequently, there is a pressing need to develop a systematic methodology for pneumatic source optimization to enhance the efficiency and effectiveness of seismic surveys.

The article considers coal ash and slag waste generated from coal combustion at thermal power plants as a promising technogenic resource. A comparative analysis of approaches to the utilization and processing of ash and slag waste (ASW) in China and Russia is presented. The high level of ASW integration into production chains in China is highlighted, due to well-developed regulatory frameworks, technological innovations, and integration with consuming industries. In Russian practice, despite existing initiatives and strategic documents, the ASW processing rates remain low. Key barriers are identified, including the territorial imbalance between waste generation sources and demand regions, insufficient economic incentives, and logistical difficulties. The need to adapt Chinese experience taking into account Russian specificities is noted.

The article presents the results of lithological and petrophysical studies of the Late Miocene Nutov Formation in the new area of the northeastern shelf of Sakhalin Island. Two main depositional environments were identified for the target sediments: a beach foreshore zone, represented by sandstones with high poroperm properties and a shallow shelf composed of clay-sandy-silty rocks. Based on core analysis and well-logging data, a lithological-facies model was developed to predict productive intervals. Special attention is given to the Upper Nutov Subhorizon, where commercial oil inflows were obtained. The results of this study can be applied to further development of the region’s fields.

The results of the reconstruction of source provinces for the Lower Cretaceous deposits of the Northwestern Caucasus are presented. The data obtained made it possible to clarify the paleoenvironments of the sedimentation and identify the sources of clastic material erosion. The main source of the clastic material was located to the northeast of the studied territory in the area of the Scythian Plate, and there was also a source in the southeast, in the Greater Caucasus region. In the Berriasian-Valanginian, Upper Jurassic reefs along the southern edge of the Scythian Plate were periodically eroded.

The data on the first findings of benthic fauna (foraminifera and mollusks) in the Pliocene-Quaternary sediments of the northeastern part of the Laptev Sea of the Arctic basin, obtained by studying the core of the SSDAN-1 well, are presented. The position of the Quaternary-Pliocene boundary in the borehole section is clarified, and paleoenvironments in the Arctic paleobasin are defined.

Information about the dielectric permittivity of deposits can be useful in the interpretation of GPR data, particularly in the context of sandy-clay ground. Among the methods for measuring electromagnetic parameters, greater preference is given to the Time Domain Reflectometry (TDR) method due to its ability to perform in situ measurements while preserving the natural density and moisture content of the deposits. However, its application requires open ground, such as a trench or a quarry wall, which are rarely found at the sites of geological and geophysical work. Much more frequently, various specialists drill wells and collect samples. In such cases, instead of the TDR method for measuring dielectric permittivity, a laboratory method using a coaxial cell is employed. The substitution of one method for another leads to discrepancies in the measured values, primarily due to changes in the sample's condition compared to the natural state of the soil. Therefore, this study analyzes the magnitude of these discrepancies in artificial and natural sandy-clay deposits depending on the grain size distribution and moisture content.