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In a recent paper, Rogozin and coauthors present a morphologic/seismostratigraphic study of two small lakes, Lake Zapovednoye (LZ) and Lake Peyungda (LP), located 50‒60 km east from the alleged epicenter of the 1908 Tunguska Event (TE), a large explosion believed to have been caused by an extraterrestrial impact. Data presented in that paper suggest a similar (although not specified) origin of these two lakes and Lake Cheko, located close to the TE epicenter. This led Rogozin et al., to question the impact crater origin of Lake Cheko, whose depression was interpreted by Gasperini et al., as caused by the freefall of an extraterrestrial fragment, which survived an atmospheric explosion. We analyze Rogozin et al., data, focusing on similarities and differences between Lake Cheko, LZ and LP, to determine whether their findings are relevant to the TE problem. [ABSTRACT FROM AUTHOR]

This paper is focused on study of the geomagnetic field variation response caused by a series of earthquakes with magnitudes of Mw = 7.5–7.8 in Turkey on February 6, 2023. The initial data include high-precision observations of the geomagnetic field with a one-second sampling rate recorded at magnetic observatories in Russia and neighboring countries from middle to high latitudes. The paper analyzes the morphology of the geomagnetic signal, its amplitude-frequency characteristics, pulses in the rate of change and delays of the geomagnetic field response to earthquakes with magnitudes Mw = 7–8 depending on the distance to the source. The results suggest that the geomagnetic effect is detected best in the rate of change recordings, reaching anomalous amplitudes of 10 nT/s. The signal delay ranges from 221 to 592 s depending on the magnetic field component and the distance to the epicenter, which is in the range from 765 to 2650 km for the selected observatories. [ABSTRACT FROM AUTHOR]

The paper presents the first isotopic U–Pb study data (LA–ICP–MS method) of zircon from intrusive rocks of the Molo-Sarychat pluton situated along the deep-seated fault system of the "Nikolaev Line" in the eastern Kyrgyzstan. The intrusive rocks from this pluton belong to the high-potassic calc-alkaline to shoshonitic series. Intense Mo(–W–Cu–Au) (mainly molybdenum-porphyry) mineralization is spatially and genetically associated with this pluton. Together with the other Au, W and Cu deposits and occurrences, this mineralization is part of the extended metallogenic belt of Tien Shan; however, occurrences of molybdenum-porphyry mineralization are still rare in this belt. The concordant isotopic U–Pb ages of zircon autocrysts indicate the crystallization of quartz monzonite (293.3 ± 4.2 Ma) and monzogranite (286.6 ± 2.4 Ma) in the Early Permian. Zircon antecrysts dated at 306–320 Ma are also present. The crystallization age obtained corresponds to a post-collisional epoch of the development of this territory but the presence of the antecrysts expands the pluton emplacement to the Late Carboniferous-Early Permian, which, as a result, spanned over initially subduction-related and then post-collisional tectonic settings. Correspondingly, a post-collisional setting of the Mo(–W–Cu–Au) (molybdenum-porphyry) mineralization is established; it is related to the pluton studied and was formed after the emplacement of quartz monzonite (early stage) and monzogranite (late stage). Significant enrichment in Mo can be related to its progressing accumulation during magmatic differentiation causing the emplacement of quartz monzonite and especially monzogranite. These processes occurred under the more mature post-collisional tectonic regime, with possible formation of intermediate magma chambers in the Paleoproterozoic metamorphic rocks and ancient granitoids. The age dates determined for rocks from the Molo-Sarychat pluton are similar to those identified for the igneous and metasomatic rocks of the large Kumtor gold deposit that is also associated with the "Nikolaev Line." [ABSTRACT FROM AUTHOR]

This paper describes secondary crystallized melt inclusions trapped in magnesiochromite of lherzolite xenolith from the V. Grib kimberlite pipe (Arkhangelsk diamondiferous province). It is shown that the inclusions are microportions of melt related to magmatism, which was further formed this pipe. Daughter minerals assemblage of inclusions in magnesiochromite contain Na‒K‒Ca-, Na‒Mg-, Ca‒Mg-, Mg-, and Ca-bearing carbonates; Na–Mg carbonates with additional PO , Cl–, and SO anions; chlorides; sulfate; phosphate; and silicate. The mineral assemblage of daughter phases, the amount of carbonates (77 vol %) and silicates (tetraferriphlogopite) (15 vol %) and Ca : Na : K ratios within the inclusions indicate that this melt was an alkali-enriched carbonate liquid with a low content of SiO2 (≤6 wt %) and H2O (≤0.6 wt %). As is known, serpentine in kimberlites is a major H2O-bearing mineral, but the problem of water sources during serpentinization of kimberlites and an actual H2O content in kimberlite melts is a controversial issue. The absence of serpentine and the low H2O content (≤0.6 wt %) of the studied melt inclusions in comparison with those of kimberlites of the V. Grib kimberlite pipe (10‒14 wt %) indicate the key role of external fluids during serpentinization of these kimberlites. [ABSTRACT FROM AUTHOR]

The paper presents first data on isotopic U–Pb study (LA-ICP-MS method) of zircon from intrusive rocks of the Adyrtor intrusions – a group of small intrusives situated in the easternmost part of the deep-seated fault system of the "Nikolaev Line." Here, these intrusions cut through one of the oldest (1.8–2.6 Ga) complexes of the basement rocks of Tien Shan (metamorphic rocks of the "Kuilyu suite"). These intrusive rocks belong to the high-potassic calc-alkaline to shoshonitic series, with some geochemical signatures also of anorogenic (A-type) magmatism. These intrusions are accompanied by skarn and porphyry W–Mo–Cu–Au mineralization. Together with the other Au, W, and Cu deposits and occurrences, they are parts of the extended metallogenic belt of Tien Shan. The concordant isotopic U–Pb age data for zircon autocrysts indicate the crystallization of quartz syenite (330.7 ± 4.3 Ma) and quartz monzonite (329.5 ± 5.8 Ma) in the latest Early Carboniferous. The distinct W–Mo specialization of ore mineralization related to the intrusions studied is in agreement with the post-collisional tectonic setting during their emplacement, despite their older or similar age compared to the ore-bearing plutons in more western segments of the Middle Tien Shan, which corresponded to a subduction-related setting. This supports the possibility of the "scissor-like" (from east to west) closure of the Turkestan paleoocean that resulted in the earlier cessation of subduction in the eastern Tien Shan compared to the western Tien Shan. The rocks also contain zircon xenocrysts with older (on the order of 1.7–2.6 Ga) age, which is in agreement with the age of the host metamorphic rocks of the Tarim craton basement. This highlights the possibility of magma chamber development in the continental crust, together with the magma chambers in the metasomatically-enriched subcontinental upper mantle, the latter being common for high-potassic magmatism. [ABSTRACT FROM AUTHOR]

The structure of King's Trough and its surroundings (King's mesostructural cluster), located on the eastern flank of the Mid-Atlantic Ridge in the North Atlantic, is described in this paper. This work is based on geological and geophysical data obtained during the 55th expedition of the R/V Akademik Nikolaj Strakhov. Six provinces were identified within the southeastern part of King's Trough, based on the results of bathymetric survey. Each province has its own morphostructural feature resulting from multistage tectonic and volcanic processes, which alternate and conjugate with each other in time. According to seismoacoustic profiling data, three main types of seismic facies have been identified: (a) pelagic complexes; (b) deposits of turbidite flows; and (c) chaotic facies of gravity origin. It is shown that the anomalous magnetic field of the study area is the superposition of linear and isometric anomalies. The first were formed during the formation of the oceanic crust in the axial zone of spreading. The second are associated with volcanic massifs formed under intraplate conditions. The obtained data confirm the assumption that the formation of King's Trough was preceded by the formation of an elongated arched rise, which became a scene of intense intraplate volcanism that increased from southeast to northwest. This stage was followed by subsidence of the axial part of the rise with the formation of King's Trough and the Peake and Freen Troughs. [ABSTRACT FROM AUTHOR]

The paper presents new isotopic U–Pb data (LA-ICP-MS method) of zircon from the main types of intrusive rocks at the Kuru-Tegerek gold-copper-molybdenum skarn deposit situated in the Chatkal segment of the Middle Tien Shan. This and other gold, copper, tungsten and molybdenum deposits are parts of the extended Late Paleozoic metallogenic belt of Tien Shan. The concordant isotopic U–Pb values obtained for zircon autocrysts from the rocks of sequential intrusive phases span over the interval from approximately 323 to 311 Ma. This interval comprises the crystallization of gabbro-diorite (from 323.5 ± 2.5 Ma to 323.2 ± 6.8 Ma) and tonalite (from 321.4 ± 3.8 Ma to 311 ± 3.8 Ma). The age dates obtained for these zircon autocrysts correspond to the emplacement of these moderate-potassic intrusions in the Late Carboniferous and are almost coincident with the isotopic dates previously known for the high-potassic intrusions of the porphyry Cu–Au–Mo deposits of the Almalyk mineralized cluster (Kurama segment of the Middle Tien Shan), which were also emplaced in the Late Carboniferous (about 330–310 Ma). This corresponds to the subduction tectonic regime occurred in this region in relation to the steep-dipping (in the Kurama segment) or flat (in the Chatkal segment) subduction of a tectonic plate toward the north, under the structures of the Kazakhstan–North Tien Shan continental massif and accreted segments of the Middle Tien Shan. The intrusive rocks studied at the Kuru-Tegerek deposit contain also zircon xenocrysts (including these in the core of complex crystals) with the isotopic U–Pb age of some 1.9–2.1 Ga. These dates are in agreement with the age of metamorphic rocks in the Tarim craton basement and indicate the presence of the ancient continental crust in this segment of the Middle Tien Shan. [ABSTRACT FROM AUTHOR]

The paper presents isotopic U–Pb zircon data (LA-ICP-MS method) for the main types of high-potassic intrusive rocks of the Chorukh-Dairon W–Mo(–Cu–Au) skarn deposit situated in the Kurama segment of the Middle Tien Shan near the largest porphyry Cu–Mo–Au deposits of the Almalyk mineralized cluster. Together with the other Au, W, Mo and Cu deposits, all these deposits are parts of the extended Late Paleozoic metallogenic belt of Tien Shan. The concordant isotopic U–Pb zircon data obtained for the rocks of successive intrusion phases in the Chorukh-Dairon pluton span from about 298 Ma to 290 Ma. This interval included crystallization of monzodiorite (295.1 ± 3.3 Ma), quartz syenite (294.7 ± 2.3 Ma), quartz monzonite (294.1 ± 2.1 Ma), and monzogranite (293.0 ± 3.0 Ma). These dates correspond to the pluton emplacement at the Late Carboniferous-Early Permian boundary and highlight its younger age compared to the productive high-potassic intrusions of the porphyry Cu–Mo–Au deposits in the Almalyk mineralized cluster, the latter assigned to the Late Carboniferous (about 337–313 Ma and partially to 308–297 Ma). By contrast to the latter, which were intruded in the subduction-related environment, the emplacement of the high-potassic rock of the Chorukh-Dairon pluton occurred in the transitional subduction-related to post-collisional environment or even under an actual post-collisional regime. This allows distinguishing two pulses of ore-bearing Carboniferous-Permian high-potassic calc-alkaline to shoshonitic series magmatism in the Middle Tien Shan. Consistently, there is a metallogenic evolution in the region that was expressed in the transition from porphyry Cu–Mo–Au deposits associated with subduction-related potassic magmatism, and likely evolving toward epithermal Au-Ag deposits, to essentially tungsten (W–Mo–Cu–Au) deposits associated with younger potassic magmatism occurring rather in the post-collisional environment. [ABSTRACT FROM AUTHOR]

The history of the crustal subsidence in the Mesozoic and Cenozoic in the West Siberian Basin – the largest sedimentary basin in the world is considered. Most researchers associate its formation with post-rift crustal subsidence, which followed an episode of strong lithospheric stretching about 250 Ma ago at the Permian–Triassic transition. A characteristic feature of post-rift subsidence is a decrease in its rate in time. During the Mesozoic–Cenozoic history, the crustal subsidence rate in Western Siberia should have decreased by an order of magnitude. However, the analysis of long (700–900 km) seismic profiles in the north of Western Siberia and in the Southern Kara Sea shows that, on average, there has been an acceleration of the crustal subsidence since the beginning of the Mesozoic in these regions. Under such conditions, lithospheric stretching in them could be responsible for only a small fraction of the total crustal subsidence by 6–7 km. In Western Siberia, the crust is close to the isostatic equilibrium. Due to this, in the absence of strong stretching, the accumulation of thick sedimentary sequences in the basin could only have been caused by rock contraction in the lower crust due to prograde metamorphic reactions. To obtain the above results, we used some simple methods for the first time to analyze the structure of the sedimentary sequences in the West Siberian Basin. Detailed seismic profiles for many other deep basins on all the continents have been published. The methods of their interpretation implemented in the present paper can be easily applied to determine the role of lithospheric stretching in the formation of deep sedimentary basins on the global scale. [ABSTRACT FROM AUTHOR]

It has been demonstrated for the first time in this paper that the frequently used approximation of the Andrade rheology with only one parameter is oversimplified and might lead to incorrect conclusions when studying the internal structure of the planets of the Solar System. Instead, we have used the Andrade rheology with two empirical parameters: α and ζ. The Earth's viscoelastic Love numbers for the principal lunar semidiurnal tide M2 were computed for two viscosity profiles and for 16 100 different combinations of α and ζ. The comparison of the computed Love numbers with the measured values makes it possible to constrain the range of values of both parameters that successfully describes the rheological properties of the Earth's mantle. [ABSTRACT FROM AUTHOR]

This paper is devoted to the problem of studying the rheological properties of seafloor sediments during the sampling process with the use of a gravity corer. The problem of gravity corer penetration through the soil with a complicated visco-elasto-plastic rheology is considered. Estimation of the mechanical properties of bottom sediments is among the most important problems emerging during the exploration of the hydrocarbon fields located on the Arctic shelf. Proper evaluation of the reaction of infrastructure objects to external effects (earthquakes, large waves) is needed to reduce the risks of serious accidents on the shelf. This paper presents a new approach to determining the parameters governing the stability of the infrastructure: static elastic moduli of seafloor sediments and their plastic and viscous properties. The dynamics of gravity corer penetration, with a measurable dependency of its acceleration, acts as a source of information regarding these parameters. The inverse problem of reconstructing the mechanical properties of seafloor sediments from the characteristics of this dependency has to be solved. This paper presents the results of solving the corresponding direct problem with the use of the finite element method. The possibility to estimate the mechanical properties of seafloor sediments from data on parameters such as time passed until the complete cessation of the tube sampler and the depth of its penetration is demonstrated. [ABSTRACT FROM AUTHOR]

Topical issues on the prospects of the Voronezh Anteclise for detection of natural hydrogen occurrences are considered. The most important factor of natural hydrogen localization is the surface of the Precambrian basement. The vault itself is surrounded by a system of depressions and aulacogens, which is generally favorable for the formation of gas emanations. The presence of ultramafic and mafic rocks, distributed at different structural and age levels, is an additional material factor of the localization of natural hydrogen. The trappean formations of the Novogol Complex and the Upper Devonian basalt covers are most promising. Four gas transportation systems of different ages can be distinguished within the Voronezh Anteclise (Losevka Suture Zone; Tim- Yastrebovka and Belgorod-Mikhailovka Paleoproterozoic rift structures; depressions and aulacogens formed in the Upper Proterozoic; and structures formed in the Upper Devonian). The Precambrian–Phanerozoic unconformity surface is a transportation system and a major mega-trap, but it is "perforated" because of many circumments, through which a significant part of hydrogen is lost. This paper characterizes the surface circular and oval subsidence structures, their possible origin, and their role in hydrogen degassing. Phenomena accompanying circumments include "bleaching" of chernozems, desertification, and increased concentrations of noble metals, primarily platinum group elements (PGEs). The analysis of the mineragenic factors controlling the transportation and accumulation of natural hydrogen within the anteclise, in general, shows very high prospects for the structure considered. [ABSTRACT FROM AUTHOR]

This paper is focused on the problems of studying the thermal conditions of the Earth's crust in the transition zone from the Baltic Shield to the Barents Sea Plate, based on temperature measurements in the deep well P-1 located on the isthmus between the Srednii and Rybachii peninsulas (northeast of the Baltic Shield). A brief description of the comprehensive geophysical studies on the wellbore is given. The measurements of thermal conductivity and the concentration of radiogenic elements in borehole core rock samples are reported. The role of hydrogeological conditions has been proved to be minor in the temperature field disturbance in the well. Horner's method has been used to calculate undisturbed temperatures at the bottoms of drilling intervals and to estimate the geothermal gradient of the Archean horizons in the section where the heat flow is estimated at 32 mW/m2. The undisturbed heat flow is estimated at 20 mW/m2 for the Riphean complex of the section. The study results characterize the thermal conditions of the Earth's crust in the transition zone from the Baltic Shield to the Barents Sea Plate. [ABSTRACT FROM AUTHOR]

This paper reports the obtained analysis data on the focal mechanisms and general distribution of earthquake epicenters in the Laptev Sea region. The principal stress axes directions were calculated by the formal stress inversion method for four groups of event clusters with known focal mechanisms. The distributions of the earthquake epicenters and crust thickness were compared. According to the seismological data, the extension axis of the Gakkel Ridge on the Laptev Sea shelf currently continues in the vicinity of the group of extension detachments located along the eastern boundary of the Anisin, Zarya, and Belkovskii–Svyatonosskii rift chains. The more ancient extension axis located along the group of detachments marking the eastern boundary of the Ust'-Lena and Omoloi rift systems and continuing the Gakkel Ridge axis is currently much less active. It carries residual stresses near its intersection with the Khatanga–Lomonosov fault zone in the northwestern parts of the shelf area and with the Lena–Taimyr zone of boundary uplifts, in the southwestern part. The axes oriented along the Olenyok and Bykovskii channels and the Siberian Platform boundary form extension conditions in the eastern part and strike–slip conditions in the western part of the Lena delta area. [ABSTRACT FROM AUTHOR]

Speleothems are unique archives of information on climate, geomagnetism, and environmental conditions of the past, and have been successfully used for paleoclimatic and paleomagnetic studies in the last two decades. The uniqueness of these geological objects lies in the peculiarities of their formation and preservation of a wide range of geochemical, geological and geophysical proxies, and, most importantly, in the ability to obtain time series of the corresponding characteristics in an unprecedentedly accurate resolution using isotope-geochronological dating methods and incremental chronology. This paper presents the first results of dating the Vor speleothem from the Vorontsovskaya Cave (Krasnodar region), which preserved a record of the geomagnetic excursion, obtained by 230Th/U α-spectrometry, 14C dating, and incremental chronology. Such studies have been carried out in Russia for the first time. Despite the limitations of using the methods of isotope geochronology, it was possible to obtain an upper limit on the age of the excursion, which probably occurred no earlier than 5500–6000 years ago. By the method of incremental chronology, the duration of the main phase of the excursion Vor – 871 ± 16 years – was determined with great accuracy. [ABSTRACT FROM AUTHOR]

The reasons for the formation of rare minerals and mineral assemblages during metamorphism and metasomatosis are found to be the atypical composition of the protolith, the structural–textural heterogeneity, restricted mass transfer, and high temperatures. This is often observed under shallow conditions (pressure up to 3 kbar) during additional heating of rocks by igneous intrusions. In this paper, these questions are discussed with a series of domestic examples, the processes of mineral formation in which are studied in detail. [ABSTRACT FROM AUTHOR]

The paper deals with results of geological and geophysical study of the East Siberian Sea coastal areas are reported. Research activities started in 2018 in the frame of the State Geological Mapping Project (GK-1000/3) and continued in 2022 under support of the Russian Science Foundation. A seismo-stratigraphic scheme of the Quaternary sediment sequence has been compiled, and a conception of the paleogeographical evolution in the Late Pleistocene–Holocene has been proposed. [ABSTRACT FROM AUTHOR]

This paper describes the first finding of authigenic carbonates on the southern flank of Gakkel Ridge in its junction with the continental margin of the Laptev Sea of the Russian Federation. The samples are represented by compact magnesian calcites and aragonites, including rounded and angular fragments of terrigenous material, as well as microphytoplankton and spores and pollen of terrestrial and aquatic plants of various ages. The elemental and organochemical characteristics are indicative of the predominant oxidation conditions or those intermediate between oxidation and reduction conditions of carbonate crystallization likely due to the fact that carbonates were formed near the bottom surface. The O, C, and Sr isotopic compositions make it possible to conclude that diagenetic carbonates of Gakkel Ridge were deposited mainly in isotopic equilibrium with bottom water at a temperature of about 0°C, corresponding to measurements from the research vessel. A wide range of δ13С (from –23.5 to –37.3) is indicative of the fact that methane was an important, but not the sole source of carbon in carbonates. Based on wide variations in 87Sr/86Sr (0.70906–0.70933) correlated with δ13С values, the carbonate-forming fluid was not only modern seawater, but also diagenetic solutions coming from the sedimentary cover together with methane and methane and organic matter oxidation products. The active discharge of heterogeneous methane-bearing fluids can be related to the high modern tectonic activity of the study region. [ABSTRACT FROM AUTHOR]

The paper presents new isotopic U–Pb zircon data (LA-ICP-MS method) on the intrusive rocks from the Chinorsai massif, which is spatially and probably genetically related to the large Jilau tungsten-gold deposit. This deposit, together with the other large Au deposits (Muruntau, Zarmitan, Kumtor, etc.) is part of the largest Au (Au–W) metallogenic belt of Tien Shan. The deposit is represented by small zones of scheelitebearing skarn and later (overprinting) large stockwork of veins and veinlets with scheelite-gold mineralization that occurs within and near the intrusion. The concordant isotopic zircon U-Pb data (301.0 ± 2.6 Ma; MSWD = 2.6) are older than the isotopic zircon U–Pb data previously reported (about 288 Ma). This indicates a substantial extent of the magma emplacement and crystallization process that probably corresponded to several intrusive events or phases, which is a prerequisite for the formation of associated intrusive-related Au deposits. Also, the isotopic age determined highlights the earlier formation of gold-polymetallic-tungsten deposits as compared to Mo–W and Sn-W deposits in the region, which are related to the later Early Permian intrusions. In addition, zircon xenocrysts with much older age (from ca. 970 Ma to ca. 2200 Ma) have been identified; they probably represent the age of the orogenic basement including that of the basement terranes of the Tarim and Karakum cratons. [ABSTRACT FROM AUTHOR]

This paper describes an approach assuming that already in the sea, based on the express analysis of visually similar cores of Arctic Holocene sediments and their comparison with dated and studied in detail cores of the regional sediments, it is possible to select a material that is promising for sequence stratigraphic correlation and paleoreconstructions. The range of lithological, colorimetric (CIE L*, CIE a*, and CIE b*), geophysical (magnetic susceptibility), and geochemical (Fe/Rb, Mn/Rb, and Ti/Rb) parameters is analyzed. The most informative characteristics include the CIE b* color coordinate, magnetic susceptibility, and Fe/Rb. [ABSTRACT FROM AUTHOR]

An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X24080014 [ABSTRACT FROM AUTHOR]

The paper discusses advances and failures in solving the problems posed by V.I. Vernadsky 100 years ago. The quantity and quality of "living matter" along with its distribution on Earth are analyzed. In accordance with the competence of the author, the paper is focused on the most voluminous biogeochemical reservoir of the planet, i.e., the World Ocean. In a number of cases, the presented literature and original data demonstrate a progress in the solution of V.I. Vernadsky problems: the estimation of the quantity and the description of the distribution of living matter. In particular, new data on the role and distribution of the living matter in the oceanosphere are presented. In other cases such as the analysis of the amount of homogeneous living matter and its biogeochemical role, there is no visible progress over the past decades but possible solutions to the problem are suggested. [ABSTRACT FROM AUTHOR]

In general, stresses and strains in the oceanic plates are studied on the basis of the theory of elastic bending of thin plates. Due to the fact that the thickness of the oceanic plates is an order of magnitude less than their length, the plate thinness condition is formally satisfied with a margin. However, the major deformations are not evenly distributed along the plates and are concentrated near the subduction zone. Therefore, the effective length of these plates is less than the real one, and the thinness condition is partially not met. The corrections to bending deformations calculated according to the thin plate theory are estimated in this paper using the example of the Japanese Trench. The given formulas relate the stresses and strains in the plate at the point of sinking into the mantle with the measured trench depth and the plate dip angle. [ABSTRACT FROM AUTHOR]

Eastern Transbaikalia is a unique rare-metal province of Russia. Most of the studied deposits are associated with granitoid intrusions. Despite the high degree of knowledge of regional magmatism, a number of issues, related to both the belonging of specific massifs to magmatic complexes and the correlation of certain complexes within various structural-formation zones, remain. This paper compares the material composition and age of several petrotypical and parapetrotypical massifs, which are classified as Late Mesozoic complexes distributed within the Aginsk, Shilka, and Argun structural-formational zones of Eastern Transbaikalia. Based on the results of U–Pb dating, two stages of granitoid magmatism have been established: (1) the end of the Middle and the beginning of the Late Jurassic (163–156 Ma) and (2) the beginning of the Early Cretaceous (142 Ma). It is shown that the closely aged rocks of the Borshchovochnyi, Amudzhikan–Sretensk, and Shakhtama complexes have similar material characteristics, while the rocks of the Kukulbei complex (from three massifs) vary in composition. Elevated δ18O values (from +10.8 to +11.9‰) in the rocks of the Jurassic complexes indicate their formation mainly due to the melting of crustal material, and lower δ18O values (from +9.8 up to +10.3‰) in the Early Cretaceous granitoids suggest the contribution of a mantle source to their genesis. [ABSTRACT FROM AUTHOR]

Soft sedimentary deformation structures (SSDs) are imperative intuition into the paleotectonic history of an active tectonic setting; however, they become arduous when dealing with Neoproterozoic intracratonic regions. A lesser known stratigraphic unit of Neoproterozoic age Sharaban Formation in Pakistan was undocumented for its SSDs and other stratigraphic details. Sharaban Formation was always thought to be a unit of metaquartzites in previous studies. Though, sedimentary and metasedimentary rocks were present. These rocks are associated with primary and secondary sedimentary structures (especially SSDs). This paper aims to identify facies, primary and secondary sedimentary structures, especially SSDs, and later link them to the paleotectonic history of the region. For this purpose, a detailed field study was designed and carried out for more than a decade, with high-resolution field photographs, sketches, and plotting. Our fieldwork reveals that the formation is made up of four rock types, metasandstone, metaconglomeratic sandstone, limestone, and quartz veins. Numerous types of sedimentary structures are found like graded bedding, cross-bedding, imbrication, synsedimentary deformation structures, convolute structure, flame structure, folds and faults, chevron–type folding, ball and pillow structure, chaotic bedding, etc. The Sharaban Formation's depositional environment is represented from low energy coastal environment to possibly a braided river system, while limestone could have deposited in a lagoonal setting. Later the SSDs could have been formed as a result of seismic activity subsequently controlled by the cratonic rifting in the larger Kirana-Malani Basin. Our results reveal that the Neoproterozoic was a time of extreme changes in tectonic conditions in the Kirana Malani Basin. Additionally, the SSDs found in the Sharaban Formation may help to understand the paleo-tectonics, tectono-dynamic reconstructions and structural kinematic studies in the NE Gondwana and other terrains like India (Bilara Formation), China and Siberia. [ABSTRACT FROM AUTHOR]

The first data on the multi-isotopic S composition of sulfides of the Neoarchean banded iron formations (BIFs) of the Kostomuksha greenstone belt of Karelia (Karelian Craton of the Fennoscandian Shield) formed 2760–2740 Ma ago are presented in this paper. Pyrite associated with fine-grained magnetite has negative δ34S (to –7.8‰) and positive Δ33S (to +0.7‰) values. Pyrrhotite from stringer-disseminated ores associated with schists exhibits negative values of both δ34S (to –6‰) and Δ33S (to –0.46‰). Our data provide grounds to suggest that the BIF sulfides sourced photolitic elementary sulfur from the atmosphere, sulfate from seawater, and sulfur from magma. The S isotope ratios of sulfides reflect the interaction between abiotic (atmospheric, hydrothermal) and biotic (microbial dissimilation reduction) processes during the formation of iron deposits of the Kostomuksha greenstone belt of Karelia. [ABSTRACT FROM AUTHOR]

This paper reports the comparison results obtained for temporal variations in atmospheric pressure and soil radon concentration measured in loose sediments at three monitoring stations in the Baikal region for the period of three relatively strong earthquakes such as Bystrinskii (September 21, 2020, K = 14.6), Kudarinskii (December 9, 2020, K = 14.0), and Khubsugulskii (January 11, 2021, K = 16.0). According to the emanation monitoring data, radon release is controlled in this region by variations in atmospheric pressure. As first identified by the formalized statistical analysis, this relationship is subjected to irregularities in the course of each seismic activation studied. They are related to the earthquake preparation processes. Upon expanding the monitoring network, this discovery opens up real opportunities for developing the emanation approach to medium-term forecasting. [ABSTRACT FROM AUTHOR]

This paper is focused on discussing the existing problems and the author's original solutions to the problems of 3D computer modeling of development processes of natural hydrocarbon deposits. The transition from laboratory experiments and 3D geological modeling to the creation of 3D filtration models of a reservoir and their subsequent adaptation to the actual development history of the data is debated. The use of a refined 3D model to optimize the economic performance of a developed field is discussed. In fact, the unmanned management of oil and gas field development using a constantly adapting 3D reservoir model is justified. [ABSTRACT FROM AUTHOR]

The role of the short-lived 134Cs radionuclide in the formation of the radioecological background in the marine environment of the Arctic is studied. This paper analyzes the data collected during long-term observations of the Murmansk Marine Biological Institute, Russian Academy of Sciences, on the levels of the 134Cs radioisotope in the marine and coastal environments of the Barents and Kara seas, including the high-latitude archipelagos: soils, lichens, algae, fish, seawater, and bottom sediments. The geography of the 134Cs distribution in marine and coastal environments is also examined, and the acting and potential sources of transport of this radioisotope into marine ecosystems of arctic seas are identified. 134Cs is rarely included among radioactive contaminants nowadays, and its specific radioactivity is insignificant. Its short half-life makes it a marker of the contamination that happened recently, such as the emissions from the Fukushima-1 nuclear power plant and local sources in the region studied. The possile local sources in the Barents and Kara seas are nuclear-powered fleet facilities and glaciers of high-latitude archipelagos. Findings of 134Cs in some samples of modern bottom sediments for fjords of the Svalbard Archipelago and its outer continental shelf suggest 134Cs transport with meltwater from the Svalbard glaciers. This paper provides data on the modern background of the 134Cs specific radioactivity in the Barents and Kara seas. In the case when an increase in these background levels is detected, an immediate search for the sources of 134Cs entry into the environment must be undertaken. [ABSTRACT FROM AUTHOR]

This paper reports the results of satellite image and seismological data analysis obtained when considering the causes of a landslide on the Yelbashinskii dump at the Kolyvan anthracite deposit. The potential for determining the natural vibrations of large objects from low-frequency seismological records and monitoring thereof has been demonstrated. [ABSTRACT FROM AUTHOR]

In addition to the widely known large-volume Sukhoi Log–type gold deposits (e.g., Sukhoi Log, Verninskoe, etc.), the Lena gold province also hosts a series of objects that differ significantly in thte stratigraphic, mineralogical–petrographic, isotopic, and geochemical characteristics, as well as reserves. The Ozherel'e deposit is one of the most famous among these objects. This paper presents the main characteristics including similar and distinct features with Sukhoi Log–type deposits. The results of mineralogical–petrographic and isotopic studies provide no reason to ascribe the Ozherel'e deposit to the Sukhoi Log genetic type. [ABSTRACT FROM AUTHOR]