Russia is the leader in the diamond mining industry among all countries of the world but finds of large diamonds over 50 carats of gem quality are very rare for its deposits. For example, the 342.5 carat XXVI Congress of the CPSU diamond was recovered in 1980 from the Mir kimberlite pipe and is still the largest gem-quality diamond mined in Russia. In 2023, a 390.65 carat gem-quality diamond fragment was discovered at the Ebelyakh alluvial deposit (Western Yakutia). The modelled 3D-reconstruction of the whole diamond crystal made it possible to assume that in terms of shape it was a dodecahedroid elongated along the L3 axis, the mass of which was about 1500 carats — this is the largest gem-quality diamond fragment found in the history of diamond mining in Russia.

 This article is the first to present the results of a comprehensive study of a large diamond fragment weighing 390.65 carats. The research was carried out in the Gokhran of Russia and ALROSA using the methods of optical microscopy, photoluminescence and infrared spectroscopy. The detected inclusion in diamond was studied by Raman scattering. It was determined that the diamond belongs to type IIa according to the physical classification and has a single small inclusion in its composition belonging to the sulfide association. It was established that the studied diamond can be attributed to the CLIPPIR group of diamonds according to the totality of features. The authors tried to establish the regularities of formation of this diamond.

The calculations of the intensity of irradiation of the Earth and hemispheres with high spatial and temporal resolution were performed for the Late Pleistocene. The effect of division of seasonal irradiation of the hemispheres by phases of increasing and decreasing eccentricity of the Earth’s orbit was discovered. The effect is manifested in the fact that the intensity of summer irradiation in the Northern Hemisphere in the phase of increasing eccentricity exceeds the intensity of its irradiation in the phase of decreasing eccentricity. In the winter half-year, the opposite effect is observed in the Northern Hemisphere. In the phase of increasing eccentricity, the intensity of irradiation is inferior to the intensity of irradiation in the phase of decreasing eccentricity. In the Southern Hemisphere, in the winter half-year, a direct effect of seasonal division is observed, in the summer half-year — the opposite. The effect of seasonal division is associated with the fact that the intensity of annual irradiation of the Earth and hemispheres, as well as the amplitude of the intensity of seasonal irradiation, are determined by eccentricity. The effect of seasonal irradiation division explains the mechanism of formation and manifestation of the 100-thousand-year cycle in the change of the natural environment in the Late Pleistocene.

In this paper we present a comprehensive comparative lithological and geochemical characteristics of the Quaternary (Middle Pleistocene-Holocene) formations of the Moscow syneclise within the Chashnikovo Depression. Based on the results of X-ray fluorescence analysis, the normative mineral composition was calculated using the MINLITH program. Data on the content of major petrogenic oxides and normative mineralogy for deposits of glacial, fluvioglacial, lacustrine, fluvial and eolian-deluvial genesis were analyzed using the principal component analysis. As a result of statistical processing, 3 groups were identified that are characterized by a common mineralogical composition and geochemical features. It is suggested that these groups are temporary genetic series of deposits, where the material of more ancient deposits served as a source for the formation of subsequent ones. The article discusses the issue of calculating the CIA petrochemical index as applied to these deposits.

The article presents the first data of the U-Pb LA-ICPMS dating of the tetrapod fauna “Mastodonsaurus” (Middle Triassic). The U-Pb age (241.6 ± 1.0 Ma) of the sediments directly underlying the layers of the Inder Formation with the fauna “Mastodonsaurus” in the Kok-Tau section (Pre-Caspian Depression) indicates that the base of the Inderian Regional stage roughly corresponds to the Anisian-Ladinian boundary and can be used as the lower age limit for the distribution of this fauna. The obtained radioisotopic dating, as well as palaeontological data on the bone-bearing Bukobayian Regional stage of the Southern Urals, place the stratigraphic range of the fauna “Mastodonsaurus” within the Ladinian Stage. A palaeogeographic model of the sediment accumulation in the Eltonian and Inderian time is proposed.

In the talus of Mount Beshkosh near the city of Bakhchisarai, the zonal index species of the Upper Maastrichtian ammonite Menuites (Menuites) fresvillensis (Seunes) was found for the first time in Southwestern Crimea. This find allows us to refine the biostratigraphic scheme of the Maastrichtian deposits of Crimea and expand our understanding of the geographical distribution of this ammonite. The relatively poor assemblage of calcareous nannoplankton extracted from a rock chip from the ammonite indicates a possible origin of the find from Member XXII of the upper Maastrichtian.

The use of remote sensing techniques for geological research has become an integral part of today’s work related to the search for and exploration of mineral deposits. However, its application is limited by both natural and technical constraints. The main obstacles to the use of remote sensing in geology are considered. Dense vegetation, woodlands, clouds, atmospheric interference, sedimentary cover and snow make it difficult to obtain and interpret data. The technical limitations related to the resolution of satellite images and the availability of data are analyzed. The features of remote sensing applications in various geographical areas of Russia are described in detail. Using the example of the Kola Peninsula, the northwestern part of the Sverdlovsk region, Belgorod, Kursk and the eastern part of the Orenburg regions, the influence of relief, climate and vegetation on the conditions of geological research using remote sensing is demonstrated. It is shown how the diversity of natural conditions in Russia affects the possibilities and limitations of using remote sensing for geological purposes.

This study focuses on the results of monitoring changes in natural resource components in the steppe zone of the Southern Ural region under the technogenic influence of copper ore extraction and processing, using Earth remote sensing data. A comprehensive analysis was conducted on Landsat satellite images acquired in 2014 and 2023. The application of vegetation indices, particularly the NDVI, revealed a decline in vegetation levels around the mining and processing plant over the study period. Further analysis utilizing the Ferrous Minerals Ratio index and the “false color” method confirmed the expansion of areas occupied by waste dumps and tailings, as well as an increase in soil iron concentration. Chemical analyses confirmed the presence of elevated metal concentrations at the tailings storage facility. The findings highlight the environmental impact of the mining and processing plant and underscore the need for systematic monitoring of the situation.

This article presents the results of studies of Mesozoic lamprophyre dikes in the basins of the Shavaz, Beshtor, Kichik rivers of the Chatkal-kuramin region. A geological characteristic is given, new types of dikes are identified and described, the patterns of their spatial distribution are studied and the sequence of formation is determined. Material composition study results of the dike rocks include: analysis of the distribution of rock-forming petrogenic elements of minerals for the most representative varieties; composition of the main and accessory mineral phases based on microprobe analysis; Distribution of admixture elements in rocks based on ICP-MS data. The authors’ views on the geodynamic nature of lamprophyric magmatism are considered, the conditions for the generation of the parental magmas of dikes and the issues of metallogenic specialization.

As a result of the study of a representative collection of diamonds from the Khara-Mas river placer (Anabar, Yakutia), provided by ALROSA PJSC, using morphological analysis, IR and EPR spectroscopy, crystal distributions by basic typomorphic features such as habitus, coloration, the presence of twins and accretions, morphology of relics of the crystal growth surface, and its processes were established. dissolution, as well as plastic deformation, degree of mechanical wear, etc. The main differences between the diamonds of the Khara-Mas placer and other placers of the Anabar region are the widest possible distribution of spinel twins, as well as the association of paramagnetic centers P1 — P2 — W21. Within the framework of the previously proposed model of genetic groups combining the assumed heterogeneous primary sources of diamond demolition in the Anabara placers, a natural decrease in the proportion of crystals of high transparency, without inclusions, twins and accretions, is shown.