卷 526, 编号 1 (2026)

The research inaccessible region of Denman Glacier revealed the presence of Paleoarchean and Neoarchean blocks comparable to other protocratons of East Antarctica and the Earth as a whole, which is particularly relevant in the context of Archean geodynamic issues and determine the evolutionary stages of continental crust in Archean terranes. 

The results of U–Pb isotope-geochronological dating of a wide range of rocks from two Archean domains and tectonically framing fragments of mobile belts are presented. The Paleoarchean age (3276.6 ± 29 Ma) of tonalitic orthogneisses in the Davis Terrane, compositionally similar to TTG associations, has been confirmed. For the first time, sillimanite-garnet paragneisses were identified within the terrane, with the maximum sedimentation age of their protolith dated to 3166 ± 21 Ma. Rifting and relative crustal subsidence between 2960 and 2800 Ma are supported by amphibolite-facies metamorphism in newly formed zircon rims of gneisses and crystalline schists, dated to 2956 ± 21 Ma and 2870 ± 21 Ma, respectively.  

The consolidation of the Davis Protocraton occurred at the Mesoarchean-Neoarchean boundary, with the final stage of formation reflected in Pan-African tectono-thermal processes between 545 and 487 Ma.

The early stage of the Neoarchean Obruchev Terrane formation, first recorded in the Cape Jones, is associated with the crystallization of orthogneiss protoliths 2711 ± 8.9 Ma ago. Tectono-thermal events of the accretionary-collisional regime are constrained to the interval of 1190–1150 Ma, corresponding to the development of the Wilkes Mobile Belt, which correlates with the Albany-Fraser Orogeny in Australia.  

The Davis and Obruchev Terranes represent ancient granite-gneiss protocratons that evolved independently during the Archean-Mesoproterozoic geodynamic stage. The amalgamation of the Davis and Obruchev Archean domains into a single collage is linked to the final stage of the Rayner Orogeny and the incorporation of Antarctica into the Rodinia supercontinent 1150–900 Ma ago.

Isotope-geochronological and geochemical data on the composition and age of metasedimentary rocks distributed in the junction zone of two large structures of the fold belt - the Tuva-Mongolian microcontinent and the Khamsara terrane were obtained. The geochemical features of the rock composition and the age of the provenance make it possible to determine the identity and position of the sedimentation basin and adjacent tectonic blocks.

It has been established that the studied metasedimentary-volcanogenic strata are represented by volcaniclastites formed in the Late Cambrian time subsynchronously with the Vendian-Cambrian sedimentary cover of the microcontinent due to Neoproterozoic island-arc sources and the destruction of rocks of the ancient continental block. The metasedimentary strata are part of a residual basin located between the island-arc system and the continental block, out of connection with the sedimentary basins of the Tuva-Mongolian microcontinent.

Basalt, gabbro, and plagiogranite samples were selected from various rock blocks in the ophiolitic melanges of the Polarna uplift of the South Anyui Sutura, from which have been taken several zircon populations . One of the populations allowed us to obtain concordant ages corresponding to the time of crystallization of rocks, which amounted to 269 million years (plagiogranite), 234 million years (basalt), 151 million years (gabbro) and 141 million years (gabbro). In addition to these zircons, polychrome generations of xenogenic zircons ( 930 to 310 million cubic meters) were isolated from each rock. years) reflecting the various stages of the tectonic evolution of the Proto-Arctic basin from the earliest stage of its development. The sources of xenogenic zircons with different Paleozoic ages are probably laminated slabs of previous subductions that arose during the evolution of the ocean.

For the first time in Verkhoyanie (North-East Russia), a continuous record of the δ¹³С_org value was obtained, covering the interval from the topmost Capitanian stage of the Middle Permian to the base of the Induan stage of the Lower Triassic. In the section along the Ustupnyi Creek (South Verkhoyanie), well characterized by fossil fauna (zonal species of bivalves and ammonoids in the upper parts of the section), two negative, relatively weakly expressed excursions in the δ¹³С_org value are outlined: the Capitanian-Wuchiapingian (up to –24.7‰) and the late Wuchiapingian (up to –25.1‰). In general, the δ¹³С_org value for the section varies from –22.6‰ (the lower part of the Wuchiapingian Stage) to –25.1‰ (the upper part of the Wuchiapingian Stage). A comparison of the obtained δ¹³С_org value record with the δ¹³С_carb value record in South China, the Shangsi section, is given, demonstrating satisfactory similarity. Chemostratigraphic correlation of the two sections indicates that the upper part of the Maitaia belliformis bivalve Zone belongs to the lower Wuchiapingian stage, and not to the upper Capitanian, as previously believed.

Reconstruction of the age of provenances of terrigenous material of the Upper Neogene Ergeninskaya suite, which contains rare metal-titanium placers within the Ergeninskaya Upland of the same name, was carried out using a combination of lithological and mineralogical methods, including geochronological U–Pb dating of detrital zircon. Generalization of the obtained data indicates that the source of terrigenous material was the crusts of chemical weathering developed along the Neoproterozoic end the Mezoproterozoic  (Riphean) volcano-plutonic complexes of the Voronezh anteclise (VA) and the Ukrainian Shield (USh), almost completely eroded by now, Paleoproterozoic and Archean crystalline rocks of the basement of these tectonic structures. Most likely, the destruction products of the above-mentioned rocks participated in the structure of the main intermediate collector, the role of which should have been played by sedimentary formations of the Carboniferous age, which have an areal distribution in the south of the East European platform. The southeastern edge of the territory of the Donetsk folded structure acted as a proximal source of terrigenous material during the accumulation of the Ergeninsky placers, as indirectly evidenced by single dZr crystals with Triassic  and Carboniferous U-Pb datings.

The manifestation of Early Permian intrusive magmatism in the territory of Rudny Altai have proven for the first time by geochronological methods (U-Pb LA-ICP-MS dating of magmatic zircon). It is represented by two associations: gabbro-diorite-syenite-granite-leucogranites with an age of 300-298 Ma (Bedarevka and Orlovka massifs) and granite-leucogranites with an age of 293-286 Ma years (Verkhne-Cheremshanka massif). The gabbro and diorites have geochemical features similar to intraplate basalts and can be compared with synchronous basites of the Mirolyubovka dyke complex in the nearboring Kalba-Narym terrane. The granitoids have geochemical features close to those of A-granites. The generation of granitic magmas is most likely the result of partial melting of lower- and middle- crustal sources under the effect of mafic magmas. Analysis of geological and geochemical data allows to conclude that the Early Permian gabbro-granite magmatism in Rudny Altai may be associated with the Tarim Large Igneous Province, associated with the mantle plume.

Experiments aimed at the study of the crystallization conditions of high-pressure micas in ultramafic diamond-forming melts with variable proportions of crustal material were performed under the upper mantle conditions. Compositional variations of micas were studied in dependence on the proportions between peridotitic (ultramafic mantle) and basaltic (crustal) substrates. The crystallization of trioctahedral mica (phlogopite) proceeds in predominantly peridotitic substrate (up to 40 wt.% of the crustal component). With increasing portion of the crustal (basaltic) component in the starting system (not less than 50%), the ^VIAl/^IVAl ratio and SiO₂ content in the mineral increase, which may result in the formation of di-trioctahedral mica varieties. Significant decrease in the Mg/(Al+Ti) ratio in the mantle substance due to the introduction of the crustal material (not less than 80% of basalt) impedes the formation of trioctahedral phlogopite, which is replaced with Ti-bearing dioctahedral mica (aluminoceladonite). The competing relationships between admixtures of Ti⁴⁺ and Cr³⁺ in the composition of synthetic mica are suggested. Increase in the Ti/Cr ratio (up to 1 and higher) may indicate a high degree of involvement (> 40%) of the crustal material into mantle metasomatism. 

Fossils red-backed voles (Clethrionomys, Rodentia) were studied from the Lower Pleistocene deposits of western Siberia based on materials from Skorodum and Romanovo localities (Omsk region). Red-backed voles are found in association with archaic voles Microtus (Allophaiomys), Prolagurus, as well as Mimomys and Predicrostonyx. Dental characters of the smaller red-backed vole show its affinity to the Recent  northern red-backed vole, C. rutilus.  Some plesiomorphic morphological traits, as lower hypsodonty (height of teeth), archaic position of the posterior root of m2, etc., indicate its ancestral position in relation to the Recent species and substantiate its description as a separate species, Clethrionomys sibiricola sp. nov.  The discovery of the ancestral form of the northern red-backed vole confirms the molecular genetic data on the divergence of Siberian and European species of red-backed voles of the genus Clethrionomys in the Early Pleistocene.

Using the receiver function method applied to data from broadband seismic stations in the foothill part of the Republic of North Ossetia–Alania, the structure of the Earth's crust and upper mantle of the region was obtained, and an equivalent four-layer model was constructed. A complex, “non-standard” crustal structure was revealed. It is characterized by extremely low V_S values and high V_P/V_S ratios in its upper part. The crust-mantle transition is gradational, with a conventionally defined depth of approximately 35 km. In the upper mantle, at a depth of about 100 km, a layer of reduced V_S values is observed, likely corresponding to a Mid-Lithospheric Discontinuity (MLD). The values of the physical-mechanical properties of the rocks, necessary for setting the boundary conditions in the 3D modeling of the stress-strain state of the geological environment in the region, were estimated.

The decade-long monitoring of the stress-strain state of the earth's crust within the framework of the Southern California geomechanical model has enabled us to reveal an anomalous zone of softening of middle and upper crustal rocks. Softening occurs in the area of the Sierra Madre fault zone, located subparallel to the San Andreas fault to the south of the latter, as a result of oppositely directed deformations of the fault sides, leading to local softening of the fault area. Numerical characteristics of the anomalous zone are given, and a brief theoretical description is presented.

This paper discusses the results of experimental (simulation-based) modeling of the spatial structure of a scalar-vector sound field generated by towing a tonal low-frequency source on the shelf of the Sea of Japan. Methodologically, the experiment involved towing a 134 Hz tonal source at a depth of 29 meters along an acoustic path with variable bathymetry, at distances up to 10 km from a combined receiving system comprising a sound pressure sensor and three orthogonal components of the sound pressure gradient. Special attention was paid to investigating the interference patterns of scalar and vector fields. Quantitative characteristics and features of interference formation at different depth sections of the path are discussed. Of particular interest are the unique results comparing horizontal and vertical field components, which confirmed the presence of vortex structures in    the acoustic field of the source—a phenomenon previously identified by the authors in earlier studies on this topic. A hypothesis is proposed linking the emergence of the vertical field component to the slope of the waveguide seabed. The potential practical applications of the findings are analyzed.

The quality of natural and conditioned water is traditionally characterized by average indicators of its composition and properties. For many water management tasks, this is insufficient, and it is necessary to take into account the amplitude and frequency of fluctuations in pollutant concentrations in a wide range of frequencies, including subhourly ones. According to existing concepts, such variability (variability) should be softened during water purification. However, the article substantiates that during water treatment, the variability of impurity concentrations is preserved and can even increase, partially preserving the dynamic characteristics of natural water. Although the distribution function of the concentration of the controlled impurity is transformed during the water purification (conditioning) process, but, as shown by the example of measuring the content of fine particles (turbidity), the structural and dynamic properties of natural water are preserved. To prove this important circumstance in theoretical and applied terms, methods of statistical analysis of time series of turbidity of natural and conditioned by coagulation and filtration of water were used. It was shown, in particular, on representative arrays of subhourly experimental data obtained in different periods of the water regime of rivers in the basins of the Pacific and Arctic Oceans that conditioning, as a rule, does not decrease, but increases the coefficient of variation of turbidity. At the same time, coefficients of determination of quantile diagrams close to unity are observed and cause-and-effect relationships between the controlled indicators of the water received for treatment and purified water are preserved.

The possibility of achieving carbon neutrality of the global economy is studied taking into account alternative demographic scenarios that assume depopulation, estimates of global net emissions of greenhouse gases are made taking into account their absorption by the planet's forests and the development of technologies for the capture and storage of carbon dioxide. An analysis of the probable dynamics of the most important climate factor - volcanic activity - is carried out, estimates of its change in the 21st-22nd centuries are made. Using a set of models of the global climate system, calculations of the average global temperature for the proposed scenarios are made, and their results are compared with other works.

It is shown that the combination of rapidly falling birth rates in all countries of the world and the expected increase in global volcanism are capable of keeping changes in the average global temperature within relatively safe limits even at the current low rates of decarbonization of the global economy.

The polar vortices are large-scale objects of stratospheric circulation that have a significant impact not only on the temperature regime and ozone content in the polar stratosphere, but also on the weather and climate of high and middle latitudes. Using the ERA5 reanalysis data for 1940–2024, we identified defining trends in polar vortex dynamics over 85 years: increasing variability of the Arctic vortex and gradual strengthening of the Antarctic vortex. In the dynamics of the Arctic polar vortex, in contrast to the Antarctic one, over the 85-year period an increase in the manifestation of inconsistency can be observed, both in the vertical dynamics of the vortex and in its intra-seasonal changes. The increase in the variability of the Arctic polar vortex over the 85-year period is most noticeable in the second half of winter (in January and February), which is associated with a gradual weakening of the vortex during this period and an increase in the frequency of episodic breakdown of the vortex in different years. Over the 85-year period, there has been a gradual strengthening of the Antarctic polar vortex, most intense during the winter (from June to August) in the upper stratosphere and from mid-spring to early summer (from October to December) in the lower stratosphere. In addition, we showed that over the past 85 years there has been a significant increase in the lifetime of the Antarctic vortex, especially in the middle and lower stratosphere.