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Volume 522, Nº 1 (2025)
- Ano: 2025
- ##issue.datePublished##: 15.05.2025
- Artigos: 20
- URL: https://journals.rcsi.science/2686-7397/issue/view/22087
GEOLOGY
The age of the last ice-dammed lake of the Chui basin (Gorny Altai)
Resumo
The series of pits describes lake deposits on the southeastern edge of the Chui basin (Gorny Altai). For the first time, we made four OSL dating as 22 thousand years. It clearly showed the age of the last ice-dammed lake lake of the Chui basin. We conclude that the age of the glaciers blocking the exit from the basin corresponds to the last glacial maximum of the Upper Pleistocene.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):5-12
5-12
GEOLOGY OF ORE DEPOSITS
Late (early-middle Permian) stage of ore formation in the W–Au metallogenic belt of the southern Tien Shan: Isotopic LA-ICP-MS U–Pb dating of zircon from intrusive rocks of the Aktau and Koitash massifs (Uzbekistan)
Resumo
The paper presents isotopic U–Pb zircon data (LA-ICP-MS method) on the intrusive rocks from the Aktau and Koitash massifs, which the Lyangar and Koitash tungsten-molybdenum skarn deposits are spatially and genetically associated with. These deposits, together with the other W and Au deposits (Muruntau, Zarmitan, etc.), are part of the largest Au (Au–W) metallogenic belt of Tien Shan. The deposits are represented by zones of hydrothermally-altered skarn with scheelite and molybdenite, and later (overprinting) near- and within-intrusive stockworks of veins and veinlets of late metasomatites (propylitic and phyllic alteration) with scheelite-gold mineralization. The concordant isotopic zircon U–Pb data (269.3±2.4 Ma for quartz diorite of the Aktau massif, 268.9±1.9 Ma for granite of the Aktau massif, 278.6±2.7 Ma for granodiorite of the Koitash massif, 276.4±3.6 Ma and 270.0±2.3 Ma for granites of the Koitash massif) were obtained. A greater scatter of the isotopic U–Pb dates was obtained for granodiorite of the Aktau massif, with the two maxima decoupled, 269.1±2.8 Ma and 278.4±3.4 Ma, corresponding to zircon “autocrysts” and “antecrysts”, respectively. All this indicates essentially younger age of the intrusive rocks studied, compared to the rocks of the other tungsten and gold deposits of the Tien Shan that corresponds to the late (Early-Middle Permian) stage of the Late Carboniferous-Permian epoch of formation of these deposits, which occurred under the conditions of a mature post-collisional development of the region. The data obtained highlight the long-lasting emplacement and crystallization of the intrusive massifs studied that occurred under periodic replenishment of magmatic chambers and resulted in a protracted magmatic differentiation, with the fluid and metal accumulation in residual melts.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):13-26
13-26
GEOCHEMISTRY
Isotope effects attending decarbonation at high PT-parameters: experimental data
Resumo
Isotope effects accompanying decarbonation process during the redox interaction of carbonate with metallic Fe and Ni at high PT parameters (1200°C, 6.3 GPa) were assessed. Under these conditions, carbonate decomposition proceeds with the formation of reduced carbon (ΣC: graphite, carbides, carbon dissolved in metal) and metal oxides (wustite, Mg-wustite). The isotope effect calculated using the models of batch and Rayleigh decarbonation for carbon isotopes in the ΣC-carbonate system ranged from 1.2 to 0.5‰, for oxygen isotopes in the Mg-wustite-carbonate system from 1.1 to 0.46‰. The obtained estimates show that during redox-induced decarbonation, isotopic shifts of oxygen and carbon in the residual carbonate are directed towards its enrichment in heavy isotopes 18O and 13C. This direction of the isotopic shift is opposite in sign to the isotopic effects that arise during decarbonation with the separation of CO2 at low pressures.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):27-33
27-33
PETROLOGY
RESTITIC ORIGIN OF GARNETS AND LHERZOLITES CONTAINING THEM FROM THE MIR AND V. GRIB KIMBERLITE PIPES
Resumo
The paper presents the results of studying the chemical composition of “depleted” garnets from lherzolite xenoliths of the highly diamondiferous Mir and V. Grib kimberlite pipes. Garnets from the Mir pipe xenoliths are distinguished by their rather large sizes, up to 15 mm; the shape of the grains is often complicated by hooked and elongated formations. Garnets from the V. Grib pipe have a more rounded shape and range in size from 1 to 4 mm. Based on the content of CaO and Cr2O3, the garnets belong to the lherzolite paragenesis. Garnets from the studied xenoliths have low contents of incompatible elements and have fractionated REE distributions with a sharp decrease from heavy to light. The LREE concentrations are 10 or more times lower than in the composition of chondrite. Variations in Y and Zr contents form a trend from “depleted” peridotites to “metasomatized” lherzolites, which can be observed both within a single xenolith and within a single grain. While metasomatized garnets show an increase in Y and Zr contents from the cneter to the edge, in depleted garnets the peripheral regions of garnet grains are depleted in Y, Zr, Ti and LREE, in contrast to their central parts. These features of the chemical composition and morphology of garnets indicate their restite origin as a result of partial melting. For the first time, it has been shown that restitic lherzolites have been preserved in the upper horizons of the lithospheric mantle, the garnets in which have not been subjected to metasomatic changes.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):34-41
34-41
MINERALOGY
Glendonites in the Aptian Stage (Lower Cretaceous) of Western Siberia
Resumo
The first occurrence of glendonite (calcite pseudomorph after cold-water mineral ikaite) was described from the Aptian Stage (Tanopcha Formation) of Western Siberia. The review of Aptian-Albian glendonite record in other regions of the world is provided, and the significance of these occurrences for clarifying the climate of the terminal part of the Early Cretaceous is discussed. Aptian glendonites from the North-East of Russia are figured.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):42-48
42-48
ZIRCONIUM MINERALIZATION IN ALKALINE RHYOLITES OF THE PECHALNINSKY ORE FIELD (NORTH-EASTERN RUSSIA)
Resumo
This article discusses the mineral forms of zirconium and rare earth elements in the trachyriolites of the Pechalninsky ore field. It has been established that zirconium and REE minerals, zircon and monazite, form unusual polymineral micrograin aggregates of isometric shape and globular structure. The size of the mineral particles in these aggregates’ ranges from less than 0.01 to 1 micron. Aggregates are characterized by a high REE content and a variable chemical composition. Zircon, which dominates in these aggregates, is enriched in REE and contains a hydroxyl group in its composition. It is noted that the polymineral aggregates of the final stage of formation form spherical shapes in which the peripheral part (rim) contains the maximum amount of Zr and REE, and the central region (according to Raman spectroscopy) contains a hydroxyl group and molecular water. Zircon microcrystals are scattered throughout the rock volume, and larger aggregates tending to spherical shapes are concentrated in the fields of iron hydroxide development or on the contact of quartzfeldspar material with ironenriched zones. The joint fine accretions of zircon with REE minerals, the globular shape of the polymineral secretions, and the heterogeneity of the structure and composition of the globules suggest their formation in the postmagmatic process.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):49-60
49-60
TECTONICS
REKONSTRUKTsIYa POLEY NAPRYaZhENIY I U‒Pb-VOZRAST KAL'TsITA IZ VNEShNEY ZONY YuZhNO-VERKhOYaNSKOGO SEKTORA VERKhOYaNSKOGO SKLADChATO-NADVIGOVOGO POYaSA
Resumo
The U–Pb dating of carbonate rocks using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has enabled precise age determinations of vein calcite, which has found wide application in tectonic studies to obtain the age of displacements along faults and the corresponding stress fields. The aim of the study is to apply this approach to the fold-and-thrust structures of the southern part of the Verkhoyansk fold-thrust belt (VFTB) in the Belaya River basin within the Gornostakh Anticline. Based on structural analysis and paleostress reconstruction, three stages of deformations with approximately E-W compression, WNW-ESE extension with a dextral strike-slip component, and a sinistral strike-slip faulting correspondently were identified the first time. For the first time for the South Verkhoyansk sector, U–Pb dating of the calcite vein established the age of the extension stage at about 63 Ma, which turns out to be younger than the compression stages documented in the same region (~160–70 Ma).
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):61-68
61-68
PALEONTOLOGY
The Beaver Trogontherium cuvieri (Castoridae, Rodentia) from the Pleistocene of Central Yakutia
Resumo
The isolated upper molar M2 of the Early Pleistocene beaver Trogontherium cuvieri Fischer von Waldheim, 1814 is described from the Khondu locality in the Churapchinsky district of Yakutia. The internal structure of the tooth was studied using computed tomography and the wear process was reconstructed based on a series of CT cross-sections. The described find supplements the extremely scanty information on the Pleistocene Castoridae in Eastern Siberia.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):69-73
69-73
PALEOGEOGRAPHY
Hydrodynamic conditions of sedimentation in the high-altitude Sagan-Nur Lake (eastern Sayan) on the basis of rock magnetic data
Resumo
The results of rock magnetic study of the core Sagan-Nur-2021-I from the bottom sediments of the glacial lake Sagan-Nur, located in the central part of the Oka plateau (Eastern Sayan), are presented. Based on the study of magnetic susceptibility, anisotropy and scalar magnetic parameters, the Lake Sagan-Nur hydrodynamics is reconstructed. It is shown that the abrupt change of the Lake’s hydrodynamic environments is associated with the inflow of various volumes of the regional glacier melt waters into its basin as a result of degradation of both surface and subsurface glaciation. Taking into account the age model based on seven AMS 14C-dates, the reconstruction of changes in the hydrodynamic regime and sedimentation conditions in Lake Sagan-Nur for the last 14 thousand years in the context of climatic fluctuations over the Late Pleistocene-Holocene time is proposed.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):74-82
74-82
GEOPHYSICS
Equations of Elastic Bending of Lithospheric Plates
Resumo
At present, the bending of the lithosphere is studied on the basis of Kirchhoffʼs (1845) thin plate bending equations. However, they give an error of ~15% in the bending of thick blocks, when the thickness to length ratio is h/L = 1/4. More accurate equations of bending of thick plates by Timoshenko (1922) and Reisner (1945) are used in engineering. But even they still contain inaccuracy, because they do not take into account transverse compression in bending. The authors have obtained new more accurate equations of bending of thick plates of the second approximation, taking into account all deformations at bending, which makes them, unlike the Timoshenko–Reisner equations, mathematically completely correct. By refining the Timoshenko and Reisner equations, the new second approximation equations are not complicated, since only the numerical coefficient in the ordinary differential equation for the bending function is changed and explicit additive terms in the algebraic expressions for longitudinal stress and longitudinal and transverse displacements are added. Compared to the more complex general partial elasticity equations, the resulting bending equations neglect only small fourth-order terms (h/L)4, which, even for thick plates with a thickness equal to one-quarter of the length, are only about one percent. A universal analytical solution of the new equations, which gives a more accurate stress and strain field, has been obtained as an application to oceanic plate bending.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):83-87
83-87
ON THE VARIATIONAL SETTINGS TO THE OSCILLATION’S AND HEAT CONDUCTIVITY EQUATIONS WITHIN THE FRAMEWORK OF DISCRETE GRAVITY POTENTIAL THEORY
Resumo
The paper deals with variational settings to the oscillation’s and heat conductivity equations within the framework of the discrete potential theory. This approach makes it possible to restore the continuously distributed sources of waves and heat in various environments with relatively high accuracy from the heterogeneous data in some network points. The Dirichlet and Neumann conditions in three-dimensional space are considered.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):88-100
88-100
Dependence of Magnetic Field Variations from the Speed of the Earth's Rotation
Resumo
We analyzed the nature of the relationship between the induction of the Earth's magnetic field and the speed of its rotation. We used data from mid-latitude magnetic observations at the Mikhnevo Geophysical Observatory of Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences and the BEL, HAD, MMB and LYC observatories of the international INTERMAGNET network and data on the unevenness of the Earth's rotation. It is shown that the induction of the geomagnetic field increases with increasing speed of rotation of the Earth and vice versa decreases with its fall. We obtained a quantitative relationship has been between the absolute magnitude of the geomagnetic field induction vector and the LOD value equal to the difference between the observed and ephemeris day duration.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):101-107
101-107
Experimental and methodological seismic work on the identification and study of low-power coal seams at the Chulmakan coal field
Resumo
The results of experimental and experimental and methodical seismic work at the Chulmakan coal deposit of the Republic of Sakha (Yakutia) are presented in order to select the optimal method to clarify the general geological structure of the research site, isolate low-power coal seams, study the features of their structure, and identify tectonic disturbances. According to the data of the joint interpretation of reflected and for the first time refracted waves based on well materials, the parameters of the strike of low-power coal seams were confidently traced and clarified, as well as a number of tectonic disturbances that were not detected by drilling were revealed.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):108-116
108-116
SEISMOLOGY
EARTHQUAKE DINGGYE 07.01.2025 AT THE SOUTHERN TIBETAN PLATEAU: EXTENSION IN THE CONTINENTAL COLLISION ZONE
Resumo
Radar images from the Sentinel-1A satellite have been used to determine the displacement field in the focal area of the January 7, 2025 earthquake in the south of the Tibetan Plateau. A rupture surface model has been constructed, revealing that the earthquake occurred along one of the branches of the rift zone – Dinggye-Xainza Rift (DXR), on a fault with a strike of 187° and a dip of 55° towards the west. The maximum displacement reaches 5.1 m, with an average of 3.5 m. The rift zone is located within a sublatitudinal extension zone, north of the Main Himalayan Thrust. Modeling of the January 7, 2025 event is of great interest as it allows for a detailed examination of the focal zone's position, its relationship with regional structures, and the comparison of instrumental and geological estimates of fault displacement rates. In particular, the findings suggest that geological estimates of extension rates along faults, as well as the seismic potential of southern Tibet rift zones, may be underestimated.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):117-123
117-123
OCEANOLOGY
The impact of typhoons on water dynamics in the western part of the South China Sea
Resumo
On the basis of numerical modeling and natural data, the restructuring of water circulation in the western part of the South China Sea under the influence of typhoons formed in different areas of this region is shown.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):124-132
124-132
ON CHANGES IN THE HYDROPHYSICAL AND HYDROCHEMICAL STRUCTURE OF THE UPPER 200-METER LAYER OF THE BLACK SEA IN THE LAST DECADE AND A HALF
Resumo
According to the long-term monitoring of the north-eastern part of the Black Sea at the Gelendzhik testing site of the IO RAS, a trend of salinization and warming of the surface waters of the Black Sea has been observed in the last 15 years. As a result, the increase in salinity of the surface water layer over these years is approximately 0.5 PSU and temperature – by 0.5°C. At the same time, the density of water in the upper 300 m layer increases, which is expressed in an increase in isopycnals and a decrease in their depth. It was found that in the period 2014–2024, the depth of the redox interface did not change and in the observation area amounted to 156±9 m, while the values of the potential density at which hydrogen sulfide appears changed from 16.15±0.02 to 16.25±0.02 kg/m3. It follows that the generally accepted binding of the appearance and disappearance of hydrochemical parameters to certain values of water density cannot be considered absolute and changes over time. In the conditions of the revealed salinization and warming of the active layer of Black Sea waters in the last 15 years, the distribution of oxygen and hydrogen sulfide by depth can be considered as more stable characteristics, less susceptible to climate change, at least during the observation period of 2014–2024 described in the article.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):133-139
133-139
ATMOSPHERIC AND HYDROSPHERIC PHYSICS
On the spatial localization of atmospheric jet stream cores
Resumo
Tropopause-level jet streams are an integral part of the atmospheric general circulation and play a role in the formation of the Earth's weather and climate, and are also an object of continuous monitoring for aviation weather services of all countries. The initial and important stage of exploration jet streams includes reliable determination of their characteristics, the main ones being the latitudinal position and intensity. A simple and universal method for identifying the jet stream core in three-dimensional space containing wind data at nodes with a regular grid is proposed. The searching algorithm of wind speed maxima related to the core of the jet stream takes into account areas with a jet deviation from the west-east direction through the ratio of the zonal component of the wind speed to its absolute value. Using reanalysis fields, the position of the Northern Hemisphere jet stream cores is given at one of the synoptic hour with estimates of the intensity of individual sections of the jet. To analyze and identify differences in jet stream regimes, latitude-longitude and latitude-altitude frequency distributions were constructed for December 2010 and 2020. It is shown that three-dimensional analysis, in particular, identifying cores in highly curved sections of jet streams, allows for a more detailed determination of characteristics such as branching, merging, degree of meandering, and intensity.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):140-147
140-147
CLIMATIC PROCESSES
On the scientific justification of adaptation to climate change of socio-natural and man-made systems based on a risk-based approach
Resumo
The scientific basis for the quantitative assessment of climate change adaptation measures for critically and strategically important objects of socio-natural and man-made systems is formulated. A risk-based approach developed for climate change conditions is used as an assessment tool. An example is considered using the example of a strategically important object of the technosphere, the result of which indicates the importance of substantiating and improving the safety and security of objects of socio-natural and man-made systems from accidents and catastrophes under changed climatic conditions. At the same time, within the framework of a risk-based approach, it becomes mandatory to calculate the necessary costs to reduce risks to acceptable levels.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):148-156
148-156
SOIL SCIENCE
The Effect of Soil Moisture on the Viscosity of Pastes Prepared from Them
Resumo
It is known from the literature that the rheological behavior of soils is largely determined by the water content in pastes and soil organic matter, which is the basis of organomineral soil gels. With an increase in soil moisture, gels can swell. As a result, the viscosity of soil pastes should change. The aim of the work was to assess the effect of soil moisture on the viscosity of soil pastes. Arable horizons of soils were used in the work: sod-podzolic, gray forest, leached chernozem and chestnut. During the experiments, soil moisture was changed, but the water content in the pastes for each type of soil remained unchanged. The viscosity of soil pastes was determined by vibrational viscometry, and the size of organomineral particles in pastes was determined by laser diffractometry. For all the studied samples, the existence of two peaks in the viscosity of pastes was found, depending on soil moisture. An explanation of viscosity peaks in pastes is proposed from the perspective of changes in the structure of humic substances in organomineral gels upon reaching critical concentrations: micelles – supramolecular formations – fractal clusters. Apparently, the transition between the structural forms of humic substances under mechanical action on pastes is accompanied by the disintegration of large gel particles and the formation of a more balanced form of existence of humic substances at a given water content.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):157-163
157-163
GEOECOLOGY
The “Dusty Haze” Effect in the Atmosphere of a Megapolis
Resumo
Local anthropogenic sources of coarse aerosol (dust) in cities may cause a “dusty haze” effect in the territory adjacent to the source sites of such aerosol (construction objects, areas of reconstruction of roads and buildings), due to a sharp increase in the concentration of PM10 particles in the near-surface air. The paper analyzes two such episodes recorded in the center of Moscow in the summertime of 2021 and 2024. The variability of mass concentration and particle size distribution of dust aerosols under abnormally high atmospheric pollution (PM10 concentration above the maximum permissible concentration) have been studied. A comparison of the characteristics of urban construction dust and arid aerosol in the atmosphere of the desolate zones of Kalmykia showed similarities between them in the increased content of lithophilic elements (of natural origin). However, in the city, the concentrations of potentially toxic elements (heavy metals, metalloids, etc.) typical for urban dust are higher in aerosols from construction sources. The dusting of megalopolis atmosphere under the influence of intensive construction sources not only worsens visibility and creates uncomfortable conditions for population, but also creates great risks for the environment of the city and human health.
Doklady Rossijskoj akademii nauk. Nauki o Zemle. 2025;522(1):164-172
164-172