A.V. Golovin¹, A.A. Tarasov¹ 1Sobolev Institute of
Geology and Mineralogy Siberian Branch Russian Academy of Sciences, Novosibirsk, Russia
Keywords: kimberlites; olivine; xenoliths; sheared peridotites; morphology and variations of olivine composition, Udachnaya-East pipe; Siberian Craton.
Olivine is the major rock-forming mineral in kimberlites, and the results of numerous studies of kimberlitic olivine are widely used in most models of kimberlite petrogenesis. The composition of olivine from kimberlites is also applied in reconstructions of the composition, structure, and evolution of the lithospheric mantle beneath ancient cratons. However, a persistent problem is the identification of magmatic olivine in kimberlites and olivine derived from disaggregated mantle xenoliths, as both may display very similar morphologies. In this study, based on extensive empirical material (more than 500 olivine grains up to 5 mm in size from a single phase of volcaniclastic kimberlite of the Udachnaya-East pipe, Siberian craton) and on a compilation of previously obtained data on olivine compositions from 158 xenoliths of sheared peridotites from the same kimberlite body, we demonstrate that although the morphology of these olivines may be similar, they can be distinguished using compositional and internal structural criteria. This study also presents new data on olivine compositions from microxenoliths (20 samples) of sheared peridotites. The Mg# distribution of olivine in microxenoliths is bimodal, defining two compositional groups with Mg# ranges of 89.5–92.5 (50% of samples) and 84.5–87.5 (45% of samples), whereas olivine from xenoliths of deformed peridotites shows a unimodal Mg# distribution in which the majority of compositions (80% of samples) fall within the Mg# range of 89.5–92.5. The study presents a series of well-documented examples where olivine neoblast grains derived from disaggregated mantle xenoliths of sheared peridotites clearly acted as seeds for the growth of magmatic olivine. In addition, a unique example is described of the destruction of a microxenolith of sheared peridotite during kimberlite crystallization, manifested by the compact occurrence of non-resorbed and unzoned euhedral neoblast crystals within a 1 mm field of view in the kimberlite matrix. The largest proportion of true kimberlitic olivine occurs in the groundmass size fraction (<0.25 mm) of unaltered rocks; however, olivine of this size fraction in kimberlites worldwide remains essentially unstudied.
B.B. Kochnev1,2, N.I. Vetrova2, A.I. Proshenkin2 1Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, Russia
2Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk,Russia
Keywords: Mana Trough, East Sayan, Late Precambrian, carbonaceous sediments geochemistry, C-isotope chemostratigraphy, detrital zircon geochronology, sedimentation settings
The chemical and isotope (C and O) composition of carbonate deposits and the age distribution of detrital zircon grains from the Late Precambrian sequences of the Mana Trough from Sayan Segment of the Central-Asian Mobile Belt (CAMB) were studied. Limestones of volcanic-sedimentary Kuvai Group (Mana and Bakhta Formations) formed in open-ocean conditions have highly positive δ13C values and, with another data, allow to limit their age as Late Riphean, оr Late Tonian. Angaloy Horizon strata have near-zero or slightly positive δ13C values, and minimal detrital zircon ages about 580 Ma, allowing to resemble it to Upper Vendian (or Upper Ediacaran). In the upper part of the Anastas’ino Horizon, two pronounced positive δ13C excursions was found, contrasting to sub-zero values, and marking the base of the Cambrian Tommotian Stage. Detrital zircon age spectra from the Angaloy and lower Anastas’ino Horizons demonstrate two Neoproterozoic populations with 710 and 630 Ma peaks. Possible sources for these zircons ages are volcanic and granitoid complexes coming from Sayan segment of the CAMB. Judging from occurrence of Paleoproterozoic zircon age population in the studied sequences, complete accretion of sedimentary basin of the Mana Trough to Siberian Craton was completed at Early Cambrian. These conclusions verified by geochemical indicators of sedimentation settings and by geodynamic reconstructions from the adjacent regions.
A.M. Soldatenko1, M.S. Sudakova2, 3 1Institute of Geography of the Russian Academy of Sciences, Moscow, Russia 2Lomonosov Moscow State University, Moscow, Russia 3Earth Cryosphere Institute, Tyumen Scientific Center, Siberian Branch of the Russian Academy of Sciences, Tyumen, Russia
This article discusses the development of a methodology for creating a semi-synthetic dataset to train a neural network for the detection and segmentation of hyperbolic diffractions in ground-penetrating radar (GPR) data. The proposed method offers a solution by generating annotated data where target synthetic objects are placed onto real background sections that are confirmed to be free of the target objects. This approach enables model fine-tuning without direct manual labeling for any specific survey type. The final algorithm was successfully validated on GPR data from the Austre Grønfjordbreen. This solution will significantly simplify the analysis of the internal structure of polythermal glaciers and allow us to assess their hydrothermal structure.
K.Yu. Vasileva1,2, M.A. Rogov1,3, V.A. Zakharov 1, B.L. Nikitenko 4, E.B. Pestchevitskaya 4,
A.V. Yadrenkin4, N.K. Lebedeva4, A.A. Goryacheva4, S.N. Khafaeva4, N.A. Malyshev5, V.E. Verzhbitsky5, G.V. Ulyanov6, V.V. Obmetko5, A.A. Borodulin5 1Geological institute of RAS, Moscow, Russia 2Saint Petersburg State University, St. Petersburg, Russia 3Arctic Research Center (ARC), Moscow, Russia 4The Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences (IPGG SB RAS), Novosibirsk,Russia 5Rosneft, Moscow, Russia 6JSC “RN-GIR” Moscow branch – center for technical competentions IGIRGI, Moscow, Russia
We present data on the findings of glendonites (pseudomorphs of the cold-water mineral ikaite) in Permian, Jurassic and Lower Cretaceous sedimentary rocks, penetrated by well KS-1, drilled on the coast of the Laptev Sea. This is the only section in the world that contains glendonites of both Paleozoic and Mesozoic age, belonging to a vast time interval including three geological systems. Glendonites are found here in all stages from which they are known in northern Siberia, with the exception of those stratigraphic intervals in which glendonite finds are comparatively rare (Oxfordian, Ryazanian and Valanginian stages). KS-1 well is a unique natural archive, which reflects the most significant cooling events in the studied region during the late Paleozoic-Mesozoic.
B.B. Kochnev1,2, N.I. Vetrova2, E.V. Vetrov3, G.A. Karlova1 1Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, Russia 2Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk,Russia 3PJSC Polyus, Moscow, Russia
Keywords: Vendian, Cambrian, Ediacaran, Gorny Altai, Baratal Group, carbonate sedimentary rocks, geochemistry, carbon, oxygen and strontium isotopes, metasomatosis
The chemical and isotope (C, O, Sr) composition of carbonate deposits in three sections of the lower Baratal Group in the southeast of the Altai Mountains, which are considered as one of the oldest known fragments of the carbonate cover of oceanic uplifts preserved in the structure of the Central Asian folded belt, was studied. The contents of Fe, Mn and Sr and their ratios to each other, and to isotope parameters indicate a post-sedimentary alteration which varying within and between studied sections. For the least altered «Akkaya» section, the δ13C values are –0.4…+0.7‰, and the 87Sr/86Sr ratios vary from 0.70818 to 0.70833, which limits the age of sedimentation to the range of 550-520 Ma. In the «Kurai» and «Chagan-Uzun» sections, along with similar values, anomalously low values of 87Sr/86Sr down to 0.70662…0.70701 are observed, which are often accompanied by a decrease in δ18O values and an increase in Mn content. These unusual characteristics of carbonates are proposed to be the result of influence of the metasomatic fluids tied with underlying basalts and spatially related to Kuvai regional fault zone. In the «Kurai» section, skeletal small-shelly fossils Cambrotubulus were found, which are not known to be older than 550 Ma, and confirms the transitional terminal Precambrian – earliest Phanerozoic age of the basal sequences of Baratal Group.
E.G. KOLOMYTS
Pushchino Scientific Center, Russian Academy of Sciences, Institute of Fundamental Problems of Biology, Pushchino, Russia
Keywords: climate changes, forest biogeocenoses, geoecological monitoring, polyzonality of biogeocenotic systems, ordination analysis, empirical simulation of a climate trend
The article presents a strategy for empirical-statistical simulation modeling of the organization of forest biogeocenoses as initial objects of terrestrial geosystem monitoring. Spatial functional monitoring of forests is based on empirically established local and regional landscape-ecological relationships, which are considered as mechanisms of metabolic responses of forest geo(eco-)systems to certain climatic trends. This constitutes the novelty of the prognostic empirical-simulation concept of local (and regional) geoecological forecasting developed by the author. The property of polyzonality of local geo(eco-)systems as a way of their response to global climate changes was revealed. An ordination analysis of landscape relationships was carried out based on the main discrete parameters of the biological cycle. A local empirical simulation of the regional bioclimatic trend using the hydrothermoedaphic system of biogeocenoses was conducted, and patterns of transitions of forest communities into critical states were identified. The article describes catenary landscape-ecological structures that form regional systems of localized natural zonality, capable of simulating the main directions and scales of geosystemic restructurings. The landscape-ecological forecast itself is of an experimental nature. It is presented as a system of operations with ecological niches of the objects under study. In computational models, the course of predicted processes is reproduced using their empirical simulation by spatially distributed parameters of basic ecological niches. The basic principle of landscape-ecological forecasting has been formulated, corresponding to one of the provisions of general ecology, namely, the Gause’s law of competitive exclusion. Description of future states of biogeocenotic systems was carried out based on their current spatial organization in accordance with the fundamental properties of ergodicity of the natural environment. Certain time limitations of the empirical-simulation method of landscape-ecological forecasting are noted, and in order to avoid these limitations, it is recommended to use a more meaningful interpretation of the results of forecast calculations.
E.A. SHLAPEKO, V.V. KARGINOVA-GUBINOVA
Institute of Economics - separate division of the Federal Research Center “Karelian Research Center of the Russian Academy of Sciences”, Petrozavodsk, Russia
Keywords: Russian Arctic, Arctic zone, Arctic territories, tourism market, tourism potential, tourism development risks
The study demonstrates that the flow of tourists to the Arctic zone of the Russian Federation has been growing in recent years. The potential positive role of tourism in the socio-economic development of the Arctic, with its particular importance for ensuring the territorial integrity and security of the country, has been confirmed. Accordingly, the article substantiates the relevance of studying the process of development of Arctic tourism and the problems associated with it, specifically, of analyzing existing trends and identifying prospects for the development of Arctic tourism based on expert assessments of operators of the tourism services market in the Arctic zone of the Russian Federation, obtained during a series of interviews. These expert assessments were compared with the position of federal authorities, as reflected in regulatory documents. Data from the Federal State Statistics Service and the Unified Federal Register of Tour Operators, analyzed using applied statistics methods, were also used. It is shown that Arctic tourism is considered in regulatory documents as a tool for strengthening the sustainability of the Arctic, and its identification as a special type of tourism is based both on the commonality of its objectives and the potential to replicate successful practices. The following was revealed: for tour operators, their activities are not simply a source of income but also a vital mission, stemming from the desire to show their small homeland to a wide range of people. It has been confirmed that tour operators primarily discuss what is needed to improve the sustainability of tourism itself. It has been established that there is a significant divergence in tourism development trends, its prospects and the factors determining this for different regions of the Arctic zone of the Russian Federation. The main trends in the Arctic tourism development have been identified, including a decrease in the share of foreign citizens and changes in the quality of infrastructure. A number of recommendations are made for federal authorities on the Arctic tourism development.
T.A. TRIFONOVA1,2, O.G. SELIVANOV2, M.E. ILYINA2, A.A. MARTSEV2,3, I.N. KUROCHKIN4, Yu.N. KURBATOV2 1Lomonosov Moscow State University, Moscow, Russia 2Vladimir State University, Vladimir, Russia 3Federal State Education Institution of Higher Professional Education I.M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russia Federation (Sechenov University), Moscow, Russia 4Vladimirskaya TPP-2, “Vladimirsky” branch of PJSC “T Plus”, Vladimir, Russia
Keywords: municipal sewage sludge, deposition, sod-podzolic sandy-loam soils, surface waters, heavy metals, remediation
The article presents the results of the study of chemical pollution of sewage sludge, soil, and surface watercourses with heavy metals in the area of used sludge ponds. High total contents of Zn, Cu, Ni, Cr, Ni, Pb and the metalloid As were found in sewage sludge. The highest concentrations were found for Cu (3,2-84,2 MAC) and Zn (3,0-77,9 MAC). Sampling of soil adjacent to the sludge ponds revealed excess levels for a number of heavy metals, with the maximum concentrations detected at a distance of 3 m from the boundary of the sludge ponds. The excess for Zn and Cu amounted to 37,5 MAC and 25,4 MAC, respectively. At a distance of 25 m from the sludge ponds, the excess was found mainly for Cu (1,05-1,69 times), and at a distance of 100 m and 650 m it was revealed for Zn and Cu. The ingress of heavy metals into the soil of adjacent areas indicates that the sludge ponds were constructed without isolating protective structures. The physicochemical properties of sod-podzolic sandy-loam soil contribute significantly to soil pollution with heavy metals. In samples of surface water, as well as in soil, excess levels of Cu, Zn, Fe, Ni, and Pb were detected. Particularly high concentrations are characteristic of Cu and Zn, which is primarily due to their increased migration activity along the soil profile, compared to other heavy metals. Addressing the problem of chemical pollution of used sludge ponds with heavy metals primarily involves mandatory remediation measures, using modern technologies such as geotubation of sewage sludge. The results of these studies can be used to assess anthropogenic impacts on soil and to scientifically substantiate necessary environmental protection measures.
A.V. OSTROUKHOV, E.M. KLIMINA
Institute of Water and Ecology Problems, Far Eastern Branch, Russian Academy of Sciences, Khabarovsk, Russia
Keywords: geosystem stability, integral assessments of landscapes, geoecological mapping, landscape planning, nature management regulations, territorial planning schemes
The article examines the application of the methodology for assessing the potential natural vulnerability of landscapes using Khabarovsk Krai as an example. Based on the performed calculations, seven categories of landscapes were identified according to the degree of integral vulnerability - from extremely high to very low, and the contribution and spatial distribution of individual vulnerability components (pyrogenic, soil-cryogenic, etc.) to the overall indicator were analyzed. The territorial distribution of the assessment indicators was presented in a series of maps. It was revealed that extremely vulnerable geosystems (mainly highlands and heavily dissected mid-mountain areas with goltsy, mountain tundra communities, etc.) and highly vulnerable geosystems (mid-mountain and low-mountain areas with coniferous forests and post-pyrogenic grass-shrub communities) are insignificantly distributed, occupying 3,4 and 7,9 % of the territory of the krai, respectively. Natural complexes with low and very low values of the indicator are most widespread (44 % of the krai’s area). These are primarily flat and foothill geosystems with a wide distribution of bog, meadow-bog types of vegetation. The resulting information and cartographic database has a level of detail corresponding to a map scale of 1:500 000 and can be used in the development of territorial planning schemes at the level of “subject of the Russian Federation - municipal district” during the procedure of ecological and economic zoning of the territory and the designation of the category of “highly vulnerable landscapes” with a regulated use regime when identifying lands of high conservation value.
O.P. OSIPOVA1, N.S. DOMBROVSKAYA2 1V.B. Sochava Institute of Geography, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia 2Federal State Budgetary Institution Irkutsk Administration for Hydrometeorology and Environmental Monitoring, Irkutsk, Russia
Keywords: Baikal, ice cover duration, North Atlantic cyclogenesis, synoptic situation, ice regime
The influence of atmospheric circulation on the ice regime of Lake Baikal from 1952 to 2025 was studied. The timings of freeze-up and ice break-up of the lake in the southern, middle, and northern parts of Baikal were analyzed. Synoptic situations preceding the late freeze-up were also analyzed. It was found that changes in the timing of freezing and breaking up of the lake ice led to a reduction of the period of ice cover. Since the mid-1970s, the dates of freeze-up on Baikal have become later and have shifted from the end of December and the beginning of January to the end of January. The ice break-up dates have shifted from mid- and late May to early May and late April. Over the past 70 years, the period of ice cover on Baikal has decreased by 19 days. The maximum ice cover duration values were observed from 1955 to 1975, the minimum ones have been recorded starting from the 1980s. The shortest period of ice cover occurred in 2025. Compared to the average long-term values, the period of ice cover was 29 days shorter in the southern part, 38 days shorter in the middle part, and 22 days shorter in the north of Lake Baikal. The influence of zonal atmospheric circulation on the lake’s ice regime was revealed. Late freeze-up is preceded by the latitudinal transport of warm air masses from the Atlantic, southwestern transport of air masses in the middle and lower troposphere from the regions of Central Asia, active North Atlantic cyclogenesis, and activation of the upper frontal zone. The weakening of the Siberian anticyclone has a significant impact on the ice regime of Lake Baikal.
