The purpose of the article is to consider the possibilities of the geophysical method in solving the problem of quantitative estimation of the strength of sedimentary rocks that form the basis of engineering structures at the Kyurgellakh station of the Amur-Yakutsk Railway located 572 km away from the town of Neryungri, which is an administrative center of southern Yakutia (Russia). The problem is solved using the method of geometric electromagnetic induction sounding and a new technique that explored the attenuation of the harmonic field induced by a vertical magnetic dipole in the inhomogeneous anisotropic geological medium at the frequencies of 1.125 and 0.281 MHz in the intermediate separation zone of  5–100 m. A comparative analysis has determined a good agreement in changes of geological and geophysical estimates of the average strength of laboratory water-saturated samples and sedimentary rock mass predicted in the same state at the comparable depth of 6–12 m. The measure of agreement when using the most adequate equation of the power function is high and equals 0.815 according to the normalized coefficient of multiple determination. This means that strength is the most important factor among the frozen ground characteristics affecting the electromagnetic field attenuation at the frequencies and spacing specified, contributing no less than 80 %. The tested geophysical method can thus correctly map the distribution boundaries of different strength sedimentary rocks. The crushed and fissured rocks with the strengths below 40–35 MPa are confined to the tectonic fractures of varying directions with a polygon-like structure. Geophysical data clearly delineate the structure at the depths of 12.3–27.5 m where predominate the rocks with high strengths (50–120 MPa). The geometric EM induction sounding is recommended to use at all stages of geotechnical investigations to map the development areas of southern Yakutia by rock strength classes.

The paper presents a non-standard approach to the typification of mineral deposits in Eastern Siberia (Russia) according to hydrogeological conditions under insufficiency and unevenness of the initial information. The most rational way to solve this problem at initial research stages is to identify a number of easily determined indirect indicators that determine the selection of sites promising for drilling hydrogeological wells. The author uses the method of system analysis including two main stages of analysis and synthesis, which result in the typification of the objects under study in accordance with the assigned tasks. The developed methodology is used for various purposes: structural hydrogeological zoning of the Ilim-Lena plateau with associated main iron ore deposits of Eastern Siberia, typification of alluvial deposits of the Lena gold ore region according to the complexity degree of engineering hydrogeological conditions, identification of the sites with high water abundance in the oil and gas fields of Eastern Siberia.

The purpose of the study is to evaluate the possibility of using the mathematical apparatus of spatial rotations to solve the determination issues of the nature and age of natural remanent magnetization vectors under complex tectonic dislocations of rocks manifested in the areas of modern folded structures of platform framing. Dynamic physical-geological models are shown to be useful when forming complex tectonic-magmatic systems. Mathematical (computer) modeling in comparison with other methods of studying geological processes features higher accuracy, cost-effectiveness and unambiguity of data interpretation in achieving the set goal. On the basis of dynamic physical-geological model of complex folding, an algorithm is developed and the results of mathematical modeling of natural remanent magnetization vectors are given for solving direct and inverse problems on correct application of the fold test under complex rock deformations. The dynamic physical-geological model of complex folded structure formation shows that the characteristic natural remanent magnetization vectors identified in laboratory experiments on demagnetization can be used to determine their age relative to the folding stages, and, depending on this, fully or partially restore the number, sequence and direction of tectonic dislocations. This will enable us to solve the mineralogenic and geodynamic problems of folded region development more effectively on the basis of paleomagnetic data.

The purpose of the presented work is a thorough determination of the characteristics of the coastal sands in Vietnam for the subsequent study of their sorption capacity. The objects of the study are sand samples collected on the banks of the Hong River (near the capital Hanoi), ThuBon (Quang Nam Province), Thachhan (Quangchi Province) and on the sea coast near the city of Hatin. Various industrial and agricultural enterprises are located in these places, in addition, the travel industry is actively developing here. The subject of the study is the granulometric characteristics of sand and its mineralogical composition. To study the mineralogical composition of sand samples the method of X-ray phase analysis is used, which allows to determine the mineralogical composition of the studied samples on the basis of the X-ray images obtained. It has been found that the mineral α-quartz SiO₂ prevails in their composition, and there is also a certain amount of α-corundum Al₂O₃ as well as other impurities. To study the granulometric characteristics of the sands, the standard method of sieve analysis is used. The proportions of various fractions of sand samples, the average grain size, uniformity coefficient, bulk weight, porosity, as well as the specific surface area have been determined.

It is known that all our knowledge about the industrial brines of the Siberian platform was obtained while drilling wells for oil and gas whereas targeted studies of brine-bearing horizons in deep wells for hydrocarbons are hardly conducted. One of the reasons is the high daily rate in the drilling cycle resulting in carrying out strictly limited additional works not related to drilling. Meanwhile, the geological results including the forecast, the estimation of the calculated parameters of the section productive intervals, the exploration and development methodology of deposits of industrial metal-bearing brines with abnormally high reservoir pressure directly depend on the data of the hydrodynamic studies. Today, large companies – subsurface users of the south of the Irkutsk region are tasked to determine the methodology of short-term pilot releases, which provides correct input data for reserve calculation of industrial brines of natural inter-salt carbonate fractured reservoirs of the hydrogeological halogen-carbonate formation. To determine a reliable permeability coefficient under the experimental filtration work, it is necessary to achieve a quasi-stationary filtration mode. The optimal mode is an intermittent one of brine release with a constant flow rate at the same time intervals with a continuous recording of pressure changes by the telemetry system. The results of pilot releases implemented at the Znamenskiy site of the Angara-Lena deposit of industrial lithium-bearing brines have been considered. The release methods enabling the performance of experimental filtration work in a short time, and applicable in well construction for hydrocarbon production have been proposed. Surface users can carry out the research using the proposed methodology in the case when the well bottom unexpectedly opens a brine formation with an abnormally high reservoir pressure of the fluid system. The implementation of experimental filtration work employing the described methods allows the subsoil users to substantiate the resource base of industrial brines and the elements in them including lithium, rubidium, cesium, bromine, iodine and other rare, trace elements and mineral salts.

The article describes the history of the origin and development of friendly relation in Russian-Mongolian cooperation in the fields of higher education and science on the example of Irkutsk National Research Technical University (former Irkutsk Polytechnic Institute, Irkutsk State Technical University) Irkutsk, Russia and the Mongolian University of Science and Technology (former Mongolian State University, Mongolian Polytechnic Institute) Ulaanbaatar, Mongolia. The author analyzes basic scientific interests of the teaching staff of these universities of Eastern Siberia and Mongolia, which are geographically the closest neighbors. Based on archival materials and published works, a detailed description of training scientific and pedagogical personnel for Mongolia at the Irkutsk university from 1960 to 2022 is given as well as the thematic scope and the nature of field and research work are described. Moreover, the activity results of the Kerulen International Geological Expedition, which was the result of many years of friendly relations between Russia and Mongolia in the field of education and science are presented. The conducted work clearly demonstrates an example of specific achievements in the fields of geological surveying, research and teaching activities of the academic staff of higher educational institutions of the two countries.