The main problems of the Kasimovian-Gzhelian (Upper Pennsylvanian) and Permian stratigraphy at the territory of Central Siberia are considered. Five structural-facies areas were identified: Tunguska, Lena-Yenisei, Vilyuy, Taimyr and Verkhoyanian (Verkhoyansk Region). Each of these areas is subdivided into structural-facies zones or districts characterized by a unique sequence of local strata (formations, subformations, units). To correlate the Upper Pennsylvanian – Permian deposits within each of the three regions – Siberian Platform, Taimyr, and Verkhoyanie, - independent regional stratigraphic scales are used, with their subdivisions based on the vertical sequence of paleontological complexes and stages of sedimentation. The Upper Pennsylvanian – Permian sediments of the Siberian Platform are considered as part of seven successive regional horizons (from bottom to top): Katian (the upper part), Klintaygian, Burguklian, Peliatkian, Degalian, Gagarieostrovian, and Ivakinian. In Taimyr, this interval corresponds to the Turuzavian, Byrrangian, Sokolinian, Bajkurian, Ledianian, Ivakinian regional horizons, and in Verkhoyanie – to the Kygyltassian, Khorokytian, Echian, Tumarian, Delenzhian, Dulgalakhian, Khalpirkian and Nekuchanian (the base part) regional horizons. The regional stratigraphic scales of the Siberian Platform, Taimyr, and Verkhoyanie are compared with the International Chronostratigraphic Scale. For all studied structural-facies areas, correlation schemes are presented that can be used as a framework for new (modern) Upper Paleozoic regional stratigraphic schemes of the Siberian Platform and its folded framing.

The paper reports the results of research conducted in the southeastern flank of the In’yaliDebin synclinorium located in the central part of the Verkhoyansk-Kolyma folded area. The main tectonic structure here is the Momontai syncline composed of Middle Jurassic clastic rocks. The syncline is unconformably overlain by the Late Jurassic volcanic and volcaniclastic rocks of the Uyandina-Yasachnaya volcanic arc. A sharp angular unconformity between the intensely deformed Middle Jurassic rocks and Upper Jurassic volcanics is described for the first time in this region. Two deformation stages are recognized. The compressive complex folding of Middle Jurassic clastic rocks has a NW strike, while the superposed large simple open folds of Upper Jurassic volcaniclastic strata are WE-oriented. The first-stage deformation is represented by tight asymmetric, concentric, cylindrical, rarely conical folds. Large, sometimes isoclinal folds overturned to SW are described. Compression and tension axes were calculated using the measurements of the orientation of fault planes and striae on the slickensides. The compression axes determined for tectonic structures of the NE limb of the Momontai syncline are almost normal to the strike of folds of the first deformation stage. Thus, it is established that the structural paragenesis including bedding-plane detachment faults, thrusts, normal faults, and strike slips was formed in the single stress field together with the development of folds of the first deformation stage. Accumulation of the studied Middle Jurassic rocks occurred in near-shore shelfal environments of sedimentation, sometimes changing to deltaic ones. The conglomerates and sandstones contain large, poorly rounded boulders of quartzite and limestone, as well as pebbles of mudstone and volcanic rocks, which is indicative of the proximity of clastics provenances. In the late Middle Jurassic or the early Late Jurassic, this part of the In’yali-Debin synclinorium underwent intense folding of NW strike. Accumulation of Late Jurassic volcanogenic rocks of the Uyandina-Yasachnaya arc and intrusion of subvolcanic rocks took place on/into the already deformed Middle Jurassic strata. Folding of the second deformation stage occurred in post-Late Jurassic time.

A comparative analysis of typomorphic features of the minerals of different types of silicate rocks and carbonatites of the Tomtor massif is provided to establish their convergent features. To exclude the mutual influence of the rocks formed at different times, samples for investigation were taken from different scattered independent pipe bodies consisting of the rocks of melteigite-malignite composition, a sheet body of alkaline picrites, a transverse carbonatite dike located to the south from the Tomtor massif, and also unaltered nepheline syenites from the southern margin of the massif. It is demonstrated that interesting convergent features are revealed for the rock-forming and accessory minerals, including rare-metal ore minerals of various silicate igneous rocks and carbonatite formations. These features are exhibited by rockforming minerals – pyroxenes, micas, feldspars, garnets, as well as by basic and rare carbonates, oxide ore minerals, including chromium-containing spinellids, sulfide and other exotic phases. New data related to the typomorphic features of minerals confirm our earlier information about the identification of five clusters by the association of petrogenic and a number of ore components among the rocks of the Tomtor massif. The most interesting nuance in this regard was the confirmation of the convergence of a group of definitely hightemperature early magmatic elements – MgO, Cr and Ni with a group of CaO, CO₂, H₂O, P₂O₅ and Y – components that formed carbonatite derivatives. For example, the detection of significant amounts of highchromium spinellids (Cr₂O₃ up to 46%, NiO up to 0.3% in alkaline picrites To-4-1 and Cr₂O₃ up to 32% in carbonatites To-5-1) indicates the through character of their presence in these rocks. Such studies will help revealing the mineralogical criteria of the genetic relationship between silicate melts and related carbonatite derivatives, which can form mineralization rich in rare elements.

The paper presents the results of the geochemical investigation of samples from the surface bitumen occurrences in the Nyatvin stratum of the Middle Carboniferous sediments over the outcrops of the right bank of the Popovka river, a tributary of the Kolyma river, for the purpose of determining the type of naphthides and their genetic relations with the enclosing rocks. According to the obtained data, the studied samples relate to naphthides of hypergenic row, which are oxidized to a high extent in the hypergenesis zone but do not bear any evident traces of biochemical oxidizing. The detected high content of organic carbon and bitumoids in the rocks, together with the features of the distribution of relict hydrocarbons, prove evidence of the aquagenic nature of initial organic matter. In the studied samples, catagenic changes of the organic matter correspond to the average stage of mesocatagenesis, and the matter had conserved its hydrocarbon potential. This allows us to suppose that the bituminous Nyatvin stratum had generated liquid hydrocarbons and could be their source for widespread bitumen occurrences in the Middle Carboniferous sediments of the Omulev and Prikolym uplifts up to the formation of hydrocarbon pools in the submerged parts of the Indigiro-Zyryan trough. The new data on the features of group composition and chemical structure of the chloroform bitumoids and alcohol-benzene resins prove evidence of the multistage nature of migration processes and point to the mixed character of bitumen shows in the Nyatvin stratum as a result of the overlay of hydrocarbon migration fluids from the Novin suite on syngenic butumens of the Nyatvin stratum, which had already underwent substantial changes in the hypergenesis zone. From the geochemical point of view, the obtained results confirm the opinion that the Paleozoic sediments, first of all Devonian and Carboniferous, in the south-eastern part of the Indigiro-Zyryan trough are a self-object for the search of hydrocarbon pools.

A complete faunistic description of fossil animals at the location of the upper reaches of the Enge-Yuryue river in the Srednekolymsky region of Yakutia was carried out. Descriptions and standard morphometric parameters of the bone remains of mammals of the mammoth fauna are presented. Species and morphometric parameters were determined according to the standard methods described in the original article. The presented bone remains were found directly at the site at the area of approximately 60 square meters in one bone-bearing layer. The material contains data on 9 mammals of the mammoth fauna. There are also the remains of rodents, but they are not included in this work due to the complexity of identifying the species. The geological age of the finds is presumably Middle and Late Neopleistocene.

Our hydrobiological studies revealed the species composition, total abundance and a complex of dominant species of phytoplankton in 11 urban and suburban lakes of Yakutsk. In addition, water samples were collected to determine the concentrations of heavy metal ions (copper, nickel, manganese, zinc). For some chemical components, an excess over the MAC was detected. A data set was compiled from the obtained data. The data set includes 24 quantitative continuous variables characterizing the concentrations of heavy metals and the parameters of phytoplankton development. Through consecutive application of various methods of statistical analysis to the obtained data set, a significant correlation was revealed between the concentrations of heavy metal ions in water and the parameters of phytoplankton growth. It is proved that increased concentrations of zinc and copper cause a decrease in the total abundance of phytoplankton, its species richness, and affect the changes in the composition of dominant species through replacing Cyanoprokaryota species by Bacillariophyta ones. The relevance of studying the effect of heavy metal ions on the living components of the aquatic ecosystem of urban lakes in Yakutsk is confirmed, as well as suitability of phytoplankton as a test object for these studies.

The total antioxidant activity (TOA) of ethanolic and water successive extracts of Lonicera leaves and berries was studied. A spectrophotometric determination of TOA by DPPH inhibition was used. The antioxidant activity was evaluated by free radical scavenging and by the estimation of total antioxidant activities. Flavonoid compounds were determined by means of high performance liquid chromatography with a microcolumn chromatograph Milichrom A-02 (EkoNova, Russia), followed by computer processing of the results using the MultiKhrom software for Windows. Antioxidants were extracted from leaves and berries of 6 populations of Lonicera edulis Turcz and L. altaica, as well as 9 varieties of Lonicera of various origins growing in the collections of the Yakut Botanical Garden (YBS). Results of biochemical investigation showed that the content of dry susbtances in the berries varies from 10,7 to 13.4%, with 11,4 % on average; the sum of saccharides is 8,1 %, varying within the range from 6,0 (Lonicera altaica) to 13,2 (Lonicera edulis, Gorniy District, May). Total sugar content was found maximum in berries Lonicera edulis (13,2 mg/g) and minimum in L. altaica (6.0 mg/g). The content of soluble and easily hydrolyzable carbohydrates in Lonicera ranged from 5,3 to 15 mg/g of the raw mass. The content of ascorbic acid in wildgrowing Lonicera berries (51,7 – 71,2 mg %) was higher than in the varieties (31,7 – 65,5 mg %). Biochemical analysis of the berries revealed 2 of 8 detectable components - luteolin glycoside and rutin. The highest content of detected flavonoids was revealed in samples of freshly picked ripe berries of L. altaica (luteolin glycoside 51.3 ± 2.6 µg/g of raw tissue, rutin 96.3 ± 4.8 µg/g of raw tissue). The accumulation of flavonoids in cultivars varied from year to year. Comparison of Lonicera berries TOA in respect of ripeness showed that it was higher in ripe fruits (up to 50 %). Accumulation of flavonoids in the varieties changes from one year to another. A comparison of the antioxidant activity (AOA) of the berries of different maturity showed that AOA is higher in mature berries (up to 50 %). The results show that Lonicera is a potential source of both lyophilic and lipophilic antioxidants.

Different classes of fatty acids (FA) in the blood plasma of pregnant women in the North perform a triple load, ensuring optimal adaptation of the body to extreme climatic and geophysical conditions, participating in the most complex rearrangements in the body of women during this period and providing nutrition, growth and development of the fetus. The aim of this work was to study the FA profile of the blood plasma of pregnant women in order to identify biomarkers of the risk of miscarriage in the North. The blood plasma of 56 female volunteers in the first trimester of pregnancy was studied. According to the criterion of the degree of obstetric risk, all the subjects were divided into 2 groups: group 1 «Healthy» (n = 24), group 2 «Risk» (n = 32). The identification and determination of the concentration of fatty acids in the samples of blood plasma were carried out by gas-liquid chromatography with mass spectrometry. 32 plasma fatty acids were identified. A high content of saturated fatty acids (more than 80 % of the total fatty acids) was revealed in both study groups. It was established that the features of the content of individual FAs in the blood plasma of pregnant women in the first trimester can serve as biomarkers of the risk of miscarriage in the North: 1) the ratio of the content of palmitic/oleic FA is lower than 17.6 units; 2) 2.51 times lower content of short-chain and long-chain fatty acids than in women with normal pregnancy; 3) the percentage of α-linolenic PSFA is 2.4 times lower than that of healthy pregnant women; 4) lower (below 0.02 %) total (Σ) content of ω3-polyunsaturated FA (ω3-PUSFA) than in healthy pregnant women; 5) the ratio of the total content of Σω6-PUSFA / Σω3-PUSFA equal to or higher than 74:1. By using appropriate dietary supplements or by adjusting the diet of pregnant women in the first trimester in accordance with the individual FA profile, it is possible to increase the percentage of healthy pregnancy and the birth of healthy children in the North.

The soils developing on the sandy deposits of Central Yakutia were studied on the right-bank part of the Kenkeme river basin (62° 04′N, 128 ° 59′–129° 00′ E). In the studied area, landscapes are represented by early Eopleistocene formations of eluvial and solifluction genesis. The ice content of frozen sandy deposits is 30–50 %, their temperature ranges from –0.5 to –7 °С, with average values –1 ... –3 °С. The thickness of the seasonally thawed layer varies from 0.5 to 4.3 m, depending on landscape conditions, with average values of 1–2.5 m. It was established that permafrost sandy weakly-podzolized soils with profile structure O–A–AE–EB– Bf–BC–C1–C2 were formed under pine forests. Permafrost taiga gleyic weakly-podzolized (O–AT–EB–B– BCg) and peaty-gleyic (OT–T–Bg) soils are formed in the depressions under hummock dwarf birch thickets with varying moisture content. All types of soils are characterized by the predominance of coarse and medium sand fractions in the granulometric composition, acidic reaction of the medium, and very low humus content in the mineral part of the profile. Different combinations of bluish-gray and ocher-rusty smears in the gleyic horizons of permafrost taiga gleyic weakly-podzolized and peaty-gleyic soils reveal a change from the initially oxidizing environment to predominantly reducing one under the conditions of excessive moisture content

The number of wolves has increased in recent years in the Republic of Sakha (Yakutia). Il leads to reduce of wild ungulates and restrain of their growth. Our study is based on data from the winter route accounting for hunting animals from 2000 to 2020, data from the questionnaire method accounting for wolves from 2011 to 2020, and data from air accounting in 2009, 2013, and 2018 in the Republic of Sakha (Yakutia). The results of the questionnaire survey of accounting for the wolves show that their population was the highest in 2011–2012 in Yakutia. Then a decline in their number followed in 2013. A gradual increase in the number of wolves took place until 2019, and then a sharp decline in 2020. The decline in the number of wolves in 2020 is observed in three zones: Aldan, North-Eastern, and Vilyuisk. A stable number of wolves is observed in the South-Western and North-Western zones of Yakutia. An increase in the number of wolves is registered in the Central zone of Yakutia. Across the Republic, the number of wolves in 2020 was 2455 individuals. The figure is lower than last year by 1,148 individuals, or 31.9 %. The average wolf population density in the Republic was 0.01 PCs./ 1000 ha of hunting grounds. The number of lone wolves also increased to 8.4 %. The dynamics of the number of wild ungulates (elk, red deer, musk deer, and roe deer), which are the wolf’s food items, goes with the same amplitude of fluctuations as the wolf. This dynamic is explained by the relationship «predator-prey». It shows the dependence of the number of wolves on the number of wild ungulates: when they decrease, their number decreases, and vice versa. With the increase in the number of wolves, the number of hares decreases sharply (in the late 1990s and from 2008 to the present time), with a decrease in their number, on the contrary, increases (from the early 2000s to the middle of the 2000s).