U–Pb (LA-ICP-MS) geochronological studies of detrital zircon from rocks of the Early Proterozoic Khargitui Formation of the Sarma Group, distributed in the central part of the Baikal uplift of the Siberian craton basement and included into the structure of the Sarma zone of the Akitkan orogenic belt, are carried out. It is established that the Khargitui Formation comprises the rocks formed in different time intervals: >2.7, 2.15–1.95, and <1.7 Ga. It is shown that Meso- and Neoarchean age peaks (2.7–3.1 Ga) are characteristic of zircon from leucocratic gneisses, which indicates the formation of gneiss protoliths after 2.7 Ga due to the destruction of Archean granitoids in the Sarma zone of the Akitkan orogenic belt and igneous rocks in the Anabar superterrane basement of the Siberian craton. The time interval of 2.15–1.95 Ga corresponds to the accumulation of protoliths of mica–quartz schists, which is substantiated by the age of the youngest zircon grains of 2150 Ma and the age of metamorphism of these rocks of 1.95 Ga. The presence of an age peak at 1833 Ma and younger zircon grains aged in the range of 1675–1785 Ma in the sample of mica–quartz schist taken from another area of rock outcrops assigned to the Khargitui Formation indicates that the protoliths of these rocks accumulated after the formation of the Akitkan orogenic belt and the South Siberian postcollisional magmatic belt. The results obtained indicate that the rocks assigned to the Khargitui Formation of the Sarma Group of the Western Baikal region cannot be considered as a single stratigraphic unit, since they formed at different stages of the evolution of the Akitkan orogenic belt. It is shown that, based on recent data, the deposits of the Khargitui Formation should be divided into complexes of different ages (stratigraphic units), each of which corresponds to a certain stage of the geological evolution of the territory.

The age of formation of the explosion pipes of the Chapinskii complex in the Chingasan magmatic belt in the northern part of the Yenisei Ridge is determined. U–Pb dating of zircon megacrysts from alkaline ultramafic rocks has established the values of 657.7 ± 13.4 and 647.6 ± 9.7 Ma for the Natalyinskaya pipe and Pipe no. 3, respectively. The intrusion of alkaline ultramafic explosion pipes of the Chapinskii complex corresponds to the time of manifestation of alkaline ultramafic magmatism along the southern and southwestern margin of the Siberian Craton.

An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X23060144

This work focuses on petrological-and-geochemical features, as well as age of dolerites widespread within the basins of the Mara, Kamenka and Uvat rivers. The isotope geochronological data acquired for baddeleyite allowed referring origination of these rocks to the time interval 1600–1620 Ma, interpreted as the time of their emplacement. It was ascertained, that the age of dolerites represents particular geological event proceeding independently of formation of Neoproterozoic Nersinsk gabbro-dolerite complex. The Sm-Nd isotope signature indicates that parent melt generated from the metasomatic lithosphere mantle.

Приводятся результаты петрографических, геохимических и геохронологических (LA-ICP-MS) исследований раннепротерозойских терригенных пород (песчаников и сланцев) верхней части иликтинской свиты сарминской серии Байкальского выступа фундамента Сибирского кратона. Петрохимические и петрографические характеристики позволяют рассматривать песчаники иликтинской свиты как полимиктовые и граувакковые песчаники, а сланцы как граувакковые алевролиты и алевропелитовые аргиллиты. Минеральный и химический состав пород иликтинской свиты указывает на преобладание пород кислого состава в области их источника. Установлено, что породы иликтинской свиты не были подвержены раннепротерозойскому региональному метаморфизму, а вторичные изменения в породах отражают в разной степени проявленную метаморфическую переработку, связанную с раннепалеозойскими коллизионными событиями. На основании данных о возрасте регионального метаморфизма (1.95—1.98 млрд лет), а также с учетом возраста прорывающих породы иликтинской свиты гранитоидов (1.86—1.91 млрд лет), время накопления иликтинской свиты можно оценить в узком диапазоне 1.91—1.95 млрд лет. Полученные данные по возрасту детритовых цирконов из песчаников иликтинской свиты не противоречат сделанным выводам, в частности в том, что самые молодые зерна детритового циркона обнаруживаются в диапазоне 1955—1993 млн лет. В результате проведенных исследований было установлено, что основными источниками детритового материала для терригенных пород иликтинской свиты могли являться магматические и метаморфические породы раннепротерозойского Акитканского орогенного пояса при некотором добавлении материала из пород прилегающего к нему с востока Алданского супертеррейна. Анализ геодинамических условий осадконакопления в совокупности с петрографическими и геохимическими характеристиками пород позволили сделать вывод, что породы иликтинской свиты сарминской серии могли накапливаться как молассоидные образования в осадочных бассейнах, сформированных после образования Акитканского орогенного сооружения. Терригенные породы, детритовые цирконы, ранний протерозой, Акитканский орогенный пояс, Сибирский кратон New petrographic, geochemical, and geochronological (LA-ICP-MS) data have been obtained for the Early Proterozoic upper Ilikta Formation of the Sarma Group within the Baikal uplift, a basement inlier of the Siberian craton. The Ilikta Formation consists of polymictic and graywacke sandstones and shales of graywacke siltstone and silty-pelitic mudstone varieties, identified from major-element chemistry and petrography. The mineralogy and chemistry of the samples indicate their origin from a felsic source. The Ilikta Formation rocks eluded the Early Proterozoic regional metamorphism but underwent secondary alteration to different grades associated with early Paleozoic collisional events. The Ilikta Formation was deposited during the 1.91–1.95 Ga interval, as constrained by the ages of regional metamorphism (1.95–1.98 Ga) and granitic intrusion (1.86–1.91 Ga). These estimates are consistent with dating of detrital zircons from the Ilikta Formation sandstone which showed the youngest ages of 1955–1993 Ma. The detrital material for the Ilikta Formation deposition was apparently derived from the igneous and metamorphic rocks of the Early Proterozoic Akitkan orogen, and some amount of material additionally came from the adjacent Aldan superterrane located in the east. The reconstructed geodynamic environment of sedimentation, together with the petrography and chemistry of rocks, allow interpreting the Ilikta Formation of the Sarma Group as molasse accumulated in extension basins after the formation of the Akitkan orogen.

The studies are focused in the Mara–Kamenka–Uvat interfluve of the Biryusa Uplift of the basement of the Siberian Platform, where the Mara paleovolcano was recognized during the prospecting works for manganese more than 50 years ago. The specific volcano-sedimentary rocks are considered in the structure of the Late Riphean Karagas Group. Our mineralogical and petrographic studies allowed us to establish abundant high-K pyroclastic rocks, ignimbrites, and trachybasalts, which indicate a subaerial explosive character of the Mara volcano. The age of high-K volcanism of 640 Ma is based on U–Th–Pb dating of zircon. The Lu–Hf isotope systematics of zircon indicates a link of volcanism with mantle magmas. The composition and the period of the formation of rocks prevent their correlation (as was considered before) with sedimentary Late Riphean quartz and quartz–feldspar sandstones of the Karagas Group and dolerites of the Nersa intrusive complex. Specific mineralogical–petrographic features of rocks allow their use as a regional stratigraphic reference.

The authors analyze seismic and hydrogeological data recorded after a large-scale blast on 22 September 2021 in Lebedinsky open pit mine, Kursk Magnetic Anomaly. In blasting of four groups of blocks, the maximum values of PPV are determined at five observation points arranged at the epicentral distances of 1.7–4.9 km, as well as the amplitudes of the hydrogeological response are assessed in two observation wells in overlying rock mass. The main parameters of the blast-induced seismic effect are used to calculate maximum PPV from the earlier found relation. The divergence of the recorded and theoretical data is observed in the near field of the blast in the first group of blocks, at the reduced distances of 106–198 m/kg 1/3 . In blasting in sedimentary rocks at the reduced distances of 405–512 m/kg 1/3 , the difference in the wavefield is observed. The research findings can be used in drilling-and-blasting control.

At the boundary of the Meso- and Neoproterozoic, Grenville collision events were widely manifested on the margins of ancient continental blocks. Most of the sedimentary sequences that had accumulated by that time had undergone significant thermal–metamorphic changes. In many ways, this is the main reason for the lack of isotopic data for carbonate deposits in the interval of 1200–900 Ma in world practice. Sr–isotopic composition in carbonate rocks with an age of 980–920 Ma was determined in the only section of the World – the Huainan Formation of the North China Platform with accumulation time determined by U–Pb dating of detrital zircon grains. In the upper part of the Nizhny Tunguska suite of the Turukhansk uplift, among carbonate deposits, we established the presence of altered volcanic rocks, as well as weathering crust products along them – poor bauxite and chamosite ores. Based on U–Pb zircon isotope dating, the age of the volcanic rocks is 964 Ma. For the least altered limestones of the upper part of the Nizhny Tungusska Formation, received 87Sr/86Sr values are 0.70532–0.70578, which are close enough to those found in the rocks of the Huainan Formation. Geochronological age of the studied limestones gives us more correct data. These data can be used to refine the previously proposed configuration of the Sr–isotopic composition variation curve in the Early Neoproterozoic. The Nizhny Tunguska Formation is the only carbonate section of the Early Neoproterozoic in the world with correctly geochronologically substantiated dating (based on zircon from subsynchronous volcanic rocks). This compares favorably with the Huainan formation.

This paper deals with the study of syenites and sviatonossites (andradite-bearing syenites) of the Malobystrinsky massif of the Slyudyanka complex (South Baikal region, Siberia), and a large monzonite dike similar in age and composition to the rocks of the massif considered. The studied rocks belong to a series of highly ferriferous and metaluminous A-type granitoids (ASI index <1). They are characterized by SiO 2 45–65 wt. %, K 2 O+Na 2 O up to 12 wt. %, MgO <4 wt. %, TiO 2 up to 2.5 wt. %, and Al 2 O 3 up to 17 wt. %. CaO varies in a wide range, from 2.2 to 14.7 wt. %. The rocks are similar to each other in trace element composition and show patterns with troughs for Th-U, Nb-Ta and Ti. Low-amplitude negative Eu anomaly is observed in the distribution spectra of rare earth elements for the entire rock complex. The obtained Sm-Nd age of sviatonossites in the Malobystrinsky massif is 487.1±6.1 Ma (MSWD=0.99). Our results indicate that syenites and monzonites have εNd (t) –1.9…–2.8, at εSr (t) 21–30, and sviatonossites have εNd (t) –3.8…–4.1 at εSr (t) – 26. Model ages T Nd (DM) for all rock types are Mesoproterozoic (1.3–1.4 Ga). Based on the chemical and Sr-Nd isotopic composition of the magmatic rocks studied, it can be assumed that they have been generated by partial melting of lower crustal rocks (amphibolites). Crystallization of andradite garnet in syenite magma can occur due to melt contamination with metamorphic host rocks of the Slyudyanka complex.

During 2000–2022, a total of 69 of Russia’s 85 administrative regions reported 164,580 hemorrhagic fever with renal syndrome (HFRS) cases, with an annual average rate of 4.9 cases/100,000 population (105 popul.). European Russia reported 162,045 (98.5%) cases in 53/60 regions with 9.7 cases/105 popul. Asian Russia reported 2535 (1.5%) cases in 16/25 regions with 0.6 cases/105 popul. In the same period, Russia reported 668 (0.4%) fatal HFRS cases, and 4030 (2.4%) cases among children under the age of 14 years. Most HFRS cases occurred during autumn and winter. The incidence among rural residents was 6.7 per 105 popul., higher than the urban 4.4 per 105 popul.; however, among HFRS patients, rural and urban residents account for 35% and 65%, respectively. Six hantaviruses, causing HFRS of different clinical severity, were recognized as pathogens: Hantaan (HTNV) and Amur (AMUV) of Orthohantavirus hantanense species, Seoul (SEOV) of Orthohantavirus seoulense species, Puumala (PUUV) of Orthohantavirus puumalaense species, and Kurkino (KURV) and Sochi (SOCV) of Orthohantavirus dobravaense species, with the principal hosts Apodemus agrarius coreae, Apodemus peninsulae, Rattus norvegicus, Myodes glareolus, Apodemus agrarius agrarius, and Sylvaemus ponticus, respectively. It was found that 97.7% of HFRS cases are caused by PUUV, therefore, this virus plays the main role in the HFRS morbidity structure in Russia.

The isotope–geochronological and geochemical data on the age and composition of rocks of the Butugol Block, located in the eastern part of the Tuva–Mongolian microcontinent of the Central Asian Orogenic Belt, have been obtained. It has been established that the protolith for gneisses is, in one case, volcanic rocks with an age of 1009 ± 8 Ma, and in the other case, potassium meta-sedimentary rocks accumulated in continental marginal basins. The protolith of metavolcanogenic rocks of this complex were formed at the turn of the Mesoproterozoic and Neoproterozoic on the already formed crust, while the metasedimentary rocks were formed owing to the Mesoproterozoic, more rarely Paleoproterozoic and Archean, continental provenances. It has been established that the development of the Butugol metamorphic complex (Butugol Block) differs from the development of other blocks of the Earth’s crust included in the composite Tuva–Mongolian microcontinent.

The age of sedimentation (530–520 Ma) of the Teregtig Formation of South Tuva is estimated on the basis of U–Pb dating of detrital zircon grains from terrigenous rocks and Sr chemostratigraphy of carbonate rocks. It is shown that granitoids with an age of 580 Ma were the main source of detrital zircon. The presence of a representative Precambrian detrital zircon population indicates the deposition of sediments of the Teregtig Formation within the continental crustal block with a long evolution. During the accumulation of coarse-grained rocks of the Teregtig Formation, this part of the eroded area also comprised rocks of the Agardag ophiolite massif, which is evident from numerous angular clasts of olivine, pyroxenes, and Cr-spinels in the conglomerate matrix.

— In screening the venoms of various snake species, we found that the venom of the Madagascar cat-eyed snake Madagascarophis colubrinus competes with α-bungarotoxin for binding to the nicotinic acetylcholine receptor from Torpedo californica . Using liquid chromatography, a peptide that inhibits the binding of α‑bungartoxin to this receptor was isolated from the venom and named macoluxin. The amino acid sequence of this 23-amino acid peptide was determined by automatic Edman degradation. Comparison with amino acid sequences of known proteins showed that the macoluxin sequence is homologous to the α-helical region of the sequence of snake venom metalloproteinases. The peptide was synthesized by solid-phase peptide synthesis, and the study of its biological activity showed that it inhibits the binding of α-bungarotoxin to the Torpedo receptor with an IC 50 of 47 μM. Macoluxin also reversibly inhibited acetylcholine-induced currents in the muscle-type nicotinic acetylcholine receptor. This is the first data on the presence of a peptide that can inhibit the nicotinic acetylcholine receptor in the venom of rear-fanged snakes.

The paper discusses data on the elemental composition and 87Sr/86Sr, and δ18O isotopic ratios of feldspar megacrysts collected from lava flows, tuffs, and cinders of three volcanic fields in the Baikal rift system: Iya–Uda, Vitim, and Khamar-Daban, which are located within the early Precambrian, Riphean, and Paleozoic crustal blocks, respectively. Megacrysts are hosted in trachybasalts in the Iya–Uda and Khamar-Daban fields and in basanites in the Vitim field. Megacrysts belong to the following three compositional groups of minerals: (i) plagioclase in lavas of the Iya–Uda field, (ii) anorthoclase in lava flows, tuffs, and cinders of the Khamar-Daban and Vitim fields, and (iii) sanidine in the Vitim field. Elemental and isotope data suggest that megacrysts crystallized in volcanic chambers at different depth levels: anorthoclase crystallized from the most primitive magma with mantle-derived isotopic signatures at subcrustal depth levels, plagioclases were produced in deep crustal chambers during the interaction between mantle-derived magma and crustal rocks, and sanidine was captured from the upper crustal rocks.

An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X23070048

The sedimentation interval (530–520 Ma) of the Teregtig Formation deposits in southern Tuva is estimated based on U–Pb dating of detrital zircons from terrigenous deposits and Sr-chemostratigraphy of carbonate rocks. The main source area for clastic material, containing a large amount of detrital zircon grains, were rocks with an age of 580 Ma. The presence of a wide diversity of Precambrian detrital zircons indicates that sedimentation of the Teregtig Formation took place within a block of continental crust with a long evolutionary history. The presence of numerous chromites in their matrix indicates that the rocks of the Agardag ophiolite complex were also part of the eroded land during the accumulation of conglomerates of the Teregtig Formation.

—The Tuva segment of the Central Asian Orogenic Belt is characterized by the ubiquitous presence of conglomerates few tens of meters to a kilometer in thickness in early Paleozoic volcanosedimentary sequences. We present the first results of geochemical, isotopegeochemical (Sm–Nd and Rb–Sr), and U–Pb geochronological studies of granitoid boulders and pebbles from the conglomerate sequence of the early Cambrian Bayan-Kol Formation of the Systyg-Khem depression. These studies made it possible to establish several sources of clastic material as a result of the destruction of granitoids of different ages and isotope-geochemical compositions. At least two complexes of granitoids were denuded in the pre-Ediacaran tectonic block in the early Cambrian: (1) middle Ediacaran (~590 Ma) and (2) early Ediacaran (~630 Ma); the latter resulted from the melting of pre-Ediacaran island arc crust formed from a depleted mantle source (εNd(T) = +8.0 to +8.6). At present, no granitoids of this age and with such isotope-geochemical characteristics have been found within the Tuva segment. Probably, the granitoid complexes reconstructed from the results of study of clastic conglomerates are eroded or buried beneath younger deposits and do not expose. Thus, the study of clastic conglomerates from the Bayan-Kol Formation provided the first information about the Precambrian history of the tectonic block whose destruction led to the accumulation of this terrigenous sequence.

The results of scientific research on the features and priority areas of strengthening food security of the population of the northern and Arctic territories are presented. The theoretical and methodological basis was the works of scientists in the field of food security. Analytical and statistical methods, methods of analogies, and expert assessments were used. The sources of information were data on the socio-economic development of the regions of the Far North and areas equated to them, Unified Interdepartmental Information and Statistical System (EMISS), Comistat, scientific publications on the research topic. The constituent elements of food security at the country and regional levels have been identified. Approaches to solving food security in the countries of the world are considered. The assessment of the state of food independence of Russia is given. The features, risks and threats to food security in extreme living conditions associated with the destruction of the material base of agriculture, the shortage of qualified personnel in the industry, the degradation and underdevelopment of rural infrastructure, the transport inadmissibility of remote areas for guaranteed food supply to their population, the decrease in food safety and quality, the inaccessibility of the poor to high-quality and safe food in accordance with rational consumption standards, the imperfection of regulatory and legal regulation and the organization of control over the quality and safety of food. The priority directions of ensuring food security are substantiated, including increasing own agricultural production, improving interregional links of food supplies to the regions of the North and the Arctic, improving the demographic situation, developing transport and trade infrastructures in rural areas, improving regulatory and legal regulation in the field of food safety and reducing rural poverty. The new approach to food security, which differs from the traditional one, is the sustainable development of rural areas, the creation of favorable living conditions for their population, and the reduction of poverty. Recommendations and suggestions can be used in the development of directions for improving state policy to strengthen food security of the population of the North and Arctic zone, as well as in the further research work of the author.