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Xenoliths of high-alumina pyroxenites in the Quaternary basalts of the Sigurd Volcano of West Spitsbergen are spinel and spinel-garnet clinopyroxenites, spinel-garnet websterites, and websterites. The granoblastic texture with relics of subhedral magmatic texture, the change of mineral assemblages, and the signs of partial melting in the xenoliths reflect their multistage formation. The goal of our study was to determine the sequence and thermodynamic conditions of the change of mineral assemblages and to establish their age by Re-Os, U-Pb, Sm-Nd, and Rb-Sr isotope dating. It has been established that the primary assemblage in the pyroxenites, which included high-alumina Opx, Cpx, and Spl, was transformed in several stages: (1) Spl→Grt replacement with the formation of garnet-containing websterites and clinopyroxenites, (2) development of kelyphitic Opx-Spl rims over Grt grains, (3) formation of Amph, (4) exsolution with the formation of Cpx and Opx, and (5) partial melting. Comparison of the obtained results with published data shows that the primary assemblage is similar in Al₂O₃/MgO ratio to Opx + Cpx ± Spl cumulates resulted from the crystallization of basaltic melts at 1.2 GPa and the degree of crystallization of ~15%, i.e., in the lower crust (at 2.0 GPa, Grt and Cpx crystallize from the solution). The equilibrium parameters of the Grt-Opx assemblage in the pyroxenites are 1060-1310 ºC and 2.2-3.3 GPa; in the P-T diagram, their points are localized below the Spl→Grt phase transition curve, in the system CaO-MgO-Al₂O₃-SiO₂, thus corresponding to the model continental geotherm with a surface heat flow density of 60 mV/m² and somewhat higher. This indicates the Spl→Grt replacement and the formation of garnet-containing pyroxenites in the shallow-depth upper mantle. The formation of kelyphitic Opx-Spl rims over the Grt grains indicates a subsequent temperature and pressure decrease to values above the Grt→Spl phase transition curve. This is confirmed by the presence of exsolution structures in pyroxene, which formed when the temperature decreased by 100-150 ºC. The Re and Os isotope composition in the bulk samples of Spl-Grt websterites that did not undergo partial melting corresponds to an age of 457.0 ± 3.5 Ma, which reflects the time of transformation of the primary Cpx-Opx-Spl assemblage into a garnet-including one. A similar value (488.6 ± 5.9 Ma) was obtained by U-Pb dating of zircon from Spl-Grt websterite, also without signs of melting. Zircon crystals from Spl-Grt clinopyroxenite with clear signs of partial melting have typomorphic features of autochthonous magmatic zircons. They form a single age cluster of 310.7 ± 3.3 Ma, which marks the age of melt crystallization in the pyroxenites. Thus, Spl pyroxenites are, most likely, Opx + Cpx ± Spl cumulates, products of crystallization of basaltic melts in the lower crust. The subsequent Spl→Grt replacement and the formation of garnet-containing websterites and clinopyroxenites in the shallow-depth upper mantle can be regarded as an indicator of the delamination of the continental crust into the mantle, and the Re-Os isochron date of 457.0 ± 3.5 Ma is the most likely upper age bound of the crust delamination into the mantle. The subsequent uplifting of the Spitsbergen lithosphere, which was expressed as the formation of kelyphitic Opx-Spl rims over garnet, exsolution in pyroxene, and partial melting, was not far in time from the delamination stage and lasted ≤ 300 Ma.

The mineralogy of loess and loess-like sediments has important implications for the mechanisms of postdepositional alteration, as well as for environmental and geotechnical issues. The geotechnical properties of soils, their mechanical strength, and the bearing capacity of the soil foundations depend on the mineral species, their percentages, and relationships. Clay minerals control the mass transport processes which have bearing on pollution of ground and water. Loess covers vast territories on all continents, including southern Russia, West Siberia, southern East Siberia, the Russian Far East, Transbaikalia, and other regions. Loess and loess-like sediments have specific genetic, lithologic, geotechnical, stratigraphic, and geomorphic features. The mineralogy of Quaternary loess has been studied by X-ray diffraction, chemical, and particle size analyses, following the standard techniques, with reference to earlier published evidence. The study area comprises three watershed provinces in the southeastern Russian Plain (southern European Russia). The results have geotechnical and environmental applications for loess provinces.

The paper presents new data on the composition of organic matter and the molecular-weight distribution of saturated hydrocarbons in the thermal waters of the Annenskoe field. The TIC chromatograms of extracts of the thermal waters, obtained by capillary gas chromatography-mass spectrometry, revealed 98 organic compounds of biogenic, thermogenic, and technogenic origin. The technogenic components amount to no more than 5%. The geochemical odd-even preference indices of saturated hydrocarbons (CPI, ACL, OEP, and TAR_HC) are calculated. It is shown that organic matter, in particular, saturated hydrocarbons, results from two processes: thermogenic processes in the water-rock system and bacterial activity. Variations in the composition of organic matter in the Annenskoe thermal waters have been determined for the first time. They are characterized by minor fluctuations within 30 min and serious fluctuations over two years and are expressed as an increase in the portion of thermogenic alkanes and a decrease in the portion of nitrogen-containing components.

The demand for detailed bio- and lithostratigraphic research of the Prisayan Formation is significant because of the lack of its stratotype section. This leads to confusion about the meaning of the stratigraphic volume of the Prisayan Formation. On the basis of the results of a comprehensive research, a lectostratotype section that covers the whole section of the Prisayan Formation is proposed. The following three subformations are identified in the formation on the basis of lithological criteria: lower (Ust-Balei), middle (Idansk), and upper (Sukhov). Stratigraphic correlation of the Prisayan Formation with the coeval deposits of the West Siberian Plate is carried out. The common development trends of typical units of the flora of the Siberian paleofloral region are revealed in West Siberia and the Irkutsk Basin. The observed tendencies make it possible to compare the beds with Coniopteris murrayana , Sphenobaiera czekanowskiana from the lower subformation with the fossil plant assemblage of the Sharapovo Horizon; the beds with Coniopteris snigirevskiae from the middle subformation with the fossil plant assemblage of the Nadoyakh Horizon; and the beds with Raphaelia diamensis and Phoenicopsis irkutensis with the fossil plant assemblage of the Laidin Horizon of West Siberia. The Prisayan-1 palynoassemblage (PA) from the lower and middle subformations correlate with palynozones 5-7 of West Siberia. The Prisayan-2 PA corresponds to palynozone 8 of West Siberia. The paleobotanical and palynological data suggest that the stratigraphic volume of the Prisayan Formation is the upper Pliensbachian-Aalenian of the Lower-Middle Jurassic. This paper touches upon the history of accumulation of the Prisayan Formation, as well as the evolution of the paleorelief and vegetation.

Regulation of river flow due to the construction of hydroelectric power plants and dams leads to a significant transformation of floodplain ecosystems and their components downstream. One of the ways to assess the ecological state of natural landscapes is to determine the enzymatic activity. At the same time, there is undeservedly little data in the world literature on the activity of enzymes in floodplain landscapes, not only disturbed but also natural. This fact is associated with difficulties in the study of floodplain areas, highly dynamic natural objects with a strong variation of properties and parameters in space and time. With this work, we partially fill this gap by showing whether the activity of enzymes can be used to assess the ecological state of floodplain soils with long-term regulation of river flow. As an example, the Zeya River has been regulated by the Zeya hydroelectric power station since 1975. We determined the activity of enzymes (phosphatases, ureases, catalases, polyphenol oxidases and peroxidases) in five types of floodplain landscapes: meadow on the riverine floodplain; meadow, arable land and forest on the central floodplain; swamp in the near-red depression. High activity of phosphatase (max. up to 10 mg/g), and low activity of urease (max. up to 0.55 mg/g) and catalase (max. up to 0.55 g/cm³) were found. The activity of polyphenol oxidase (max. up to 85 mg/100 g) and peroxidase (max. up to 290 mg/100 g) expressed through the humus accumulation coefficient (max. 41 %) indicates the average level of soil fertility of the floodplain. The diversity of enzymes was evaluated using the Pielow index and geometric mean. It was determined that under conditions of long-term regulation, the best indicators of enzymatic activity are characteristic of soils under floodplain forest, the minimum - for arable soils. A single soil parameter that would reliably affect all enzymes has not been identified. Phosphatase, urease and catalase exhibit significant positive relationships with H & Al. Strong positive relationships of catalase with organic matter and negative with pH. The data obtained allow us to state that long-term regulation of river flow leads to a decrease in the activity and diversity of enzymes.

The present work was carried out to study the reaction of plants Darlingtonia californica Torr. on the effect of Cu, Co and Mg ions in in vitro culture. For this, the following concentrations of mineral salts were tested: 0.1 (control), 10, 25, 50, 75 and 100 μM CuSO₄∙5H₂O (which corresponds to 0.006, 0.6, 1.6, 3.2, 4.8 and 6.4 mg/l of water-soluble Cu ions); 0.1 (control), 10, 25, 50, 75 and 100 μM CoCl₂∙6H₂O (corresponding to 0.006, 0.6, 1.5, 3.0, 4.4 and 5.9 mg/l of water-soluble Co ions) and 1500 (control), 4500, 7500, 10500, 15000 μM MgSO₄∙7H₂O (corresponding to 36, 108, 181, 253, and 362 mg/l of water-soluble Mg ions). The results showed a direct significant correlation between the accumulation of Cu, Co, and Mg ions in D. californica plants depending on their content in nutrient solutions. The maximum accumulation of ions was noted after 45 days of cultivation, Cu - 138.24 mg/kg of dry matter, Co - 249.92 mg/kg and 4722.26 mg/kg Mg. It was shown that the concentrations used did not significantly affect the parameters of plant growth and development in in vitro culture. The morpho-anatomical studies confirm the high level of ecological adaptation of this species to extreme conditions. In addition, the plants did not require specific cultural conditions, they are able to grow on nutrient media rich in mineral composition at a temperature of 24±1 °C and do not require low positive temperatures for the root system. The results show that D. californica plants are able to accumulate Cu, Co, and Mg ions and tolerate high concentrations of these elements in nutrient media under in vitro conditions; however, they are not characterized by an increased need for these elements for normal growth and development.

In a comparative vein, the existing and potentially possible methodological methods for delimiting zonal-provincial associations of forest-bog and peat-bog complexes are analyzed. It is shown that on geomorphological differences of locations under conditions of continuous interaction with climate elements, soils and vegetation, their relatively autonomous development in time and space is carried out. On the example of the northern part of the Ob and Tom interfluve, in accordance with the criteria of such relative autonomy, natural indicator variations in the taxation and phytocenotic structure of indigenous marsh forests and, for comparison, dry valley pine forests are characterized. In the ranks of their modern typological and morphosculptural organization, causal relationships of ecosystem diversity and productivity with water and mineral growing conditions are considered, which clearly affect the composition of the age generations of the «mother» forest stands, undersized undergrowth and juvenile renewal groups. On the basis of the dimensions of the positive elements of the phytogenic micro- and mesorelief, large-hillock and cushion-like surfaces of oligotrophic and mesotrophic pine forests with mossy-lichen-shrub vegetation are typified, in peat deposits of which permafrost aquicludes and ice lenses-migratory are regularly localized. In especially moistened eutrophic pine forests with grass-mossy and low-grass vegetation, the phytogenic relief is considered in the system of different-height, scattered and merged tussocks, as well as near-stem mounds, which are formed by frameworks of skeletal roots draped with coniferous-leaf litter, grass rags, green Bryidae Engl. and hypnum Hypnales W. R. Buck et Vitt tows mosses. Taking into account these and a number of other factors, the trend of ambiguous settlement of self-sowing and pine Pinus L. undergrowth under the canopy of «mother» forest stands is estimated. Phytocenotic and inventory indication of pine forests, based on the system-sampling method of assessment, expands the understanding of the comparative range of variability in the structure of both marsh and upland pine forests that have reached the climax or approached the stages of self-development.

The results of long-term studies of taxonomic diversity and ecological and trophic features of the mycobiota of urban birch forests of Krasnoyarsk, which are subjected to an average degree of recreational load, are presented. 234 species of macromycetes have been identified, of which only less than half are found regularly, most of them are detected rarely or singly. The main part of the mycobiota, rich in single-species taxa, is made up of fungi of the order Agaricales Underw.; in terms of the number of species in the family spectrum, the families Russulaceae Lotsy, Agaricaceae Chevall., and Inocybaceae Jülich. are the leaders. The generic spectrum is dominated by Russula Pers., Inocybe (Fr.) Fr. and Mycena (Pers.) Roussel. The ecological and trophic structure of the mycobiota is dominated by xylotrophs, mycorrhiza formers, and humus saprotrophs. Widely specialized xylosaprotrophs predominate over xyloparasites, which are rarely found on living trees. Among the mycorrhiza-forming species, the proportion of representatives of the Russulaceae and Inocybaceae families is high. Among the humus saprotrophs, there are species characteristic of both forests and open habitats. The presence of a large number of synanthropic species in the dominant taxonomic and ecological-trophic groups of macromycetes indicates a pronounced impact of recreational pressure on the formation of mycobiota in urban forests. On the fallen birch, Hericium coralloides (Scop.) Pers, listed in the Red Data Book of Krasnoyarsk Krai, is regularly found. Several more rare species of fungi subject to protection were identified in the study area in previous years.

Fossil wood that is ca 7 million years old from Bükkábrány (Hungary) was analyzed by thermogravimetry (TG), differential scanning calorimetry (DSC) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to evaluate alterations of its chemical composition. A wood sample of bald cypress ( Taxodium distichum (L.) Rich.) from West Hungary was taken as a reference. The fossil wood was characterized by higher contents of total carbon (58.05 %) and total nitrogen (0.44 %) compared to recent wood. TG of fossil wood showed a high heterogeneity of wood substance, significant loss of polysaccharides and enrichment by lignin including more thermally stable components (> 500 °C). The enthalpy change (∆H) of combustion (thermo-oxidation) for fossil wood was significantly higher than for recent wood (-18.17 kJ/g vs. -11.41 kJ/g). Py-GC/MS analysis of fossil wood showed a significant depletion of polysaccharide pyrolysis products and an increase in lignin pyrolysis products compared to recent wood. The pyrolytic H/L ratio indicates a preferential loss of polysaccharides in fossil wood. Polysaccharide pyrolysis products were rare and represented mainly by levoglucosan. Lignin also underwent substantial changes. A dramatic decrease in monomers, an increase in short side chain compounds and the presence of demethylated/demethoxylated compounds in the composition of lignin pyrolysis products are indicative of lignin alteration (degradation). Moreover, a high abundance of styrene, cresols, phenol and phenolic compounds was observed.

The article analyzes the scientific achievements and heritage of Anatoly Platonovich Abaimov, a well-known dendrologist and forester, who have made a great contribution to the study of larch Larix Mill. species in Siberia and the Far East, larch forests in the permafrost zone, as well as the features and patterns of the forest formation process in them. Anatoly P. Abaimov has substantiated the quantitative and qualitative morphological signs to distinguish larches Gmelin ( Larix gmelinii (Rupr.) Kuzen.) and Cajander ( L. cajanderi Mayr), described their ecological specialization and clinal geographical variability of morphological features, proved an introgressive hybridization between these larch species. He characterized in detail the forestry and taxation specificity, ecological functions and dynamics of Siberian larch formations under the influence of natural and anthropogenic factors. Anatoly P. Abaimov has marked the beginning of long-term Russian-Japanese cooperation in the field of assessing the global role of the permafrost forest ecosystems in the emission and absorption of greenhouse gases. The public and pedagogical activity of Anatoly P. Abaimov is characterized. A list of scientific papers and a list of dissertations defended under his supervision are given.