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Carbonatite breccias were discovered by borehole G2 in the north of the Burannyi site in the Tomtor massif (complex) (TC) hosting the largest Sc-Y-Nb-REE ore deposit. The breccias are petrographically composite rocks consisting of fragments of dolomite, dolomite-ankerite, ankerite, and calcite carbonatites with significant amounts of F-REE carbonates, pyrite, and fluorite. They show signs of fragmentation of carbonatites and calcite rocks, transition of these fragments by younger melt-brine enriched in CO₂, F, S, and REE, and its interaction with breccia fragments. The studied rocks are classified as magmatic-fluidogenic and fluidogenic breccias, which are a unique source of information about the rock composition and deep-level processes within the TC. The trace element spidergrams of the carbonatite breccias are similar to those of carbonatites and unique high-grade Sc-Y-Nb-REE ores of the upper ore horizon of the TC. The spidergrams show enrichment in Th, Nb, La, Ce, and Nd and depletion in U, K, Sr, Zr, Hf, and Ti, as in other carbonatite complexes of the world (including those with breccias). The REE pattern shows enrichment in MREE and HREE. The formation of carbonatite breccias is accompanied by the crystallization of unique REE minerals: synchysite-(Ce), parisite-(Ce), and/or bastnaesite-(Ce), cebaite-(Ce), and burbankite. Сrystallization of REE-fluorocarbonates is associated with dolomite replacement by ankerite. The maximum amount of these minerals, as well as cebaite-(Ce) and burbankite, is found in calcite rocks in association with fluorite and pyrite. It is shown that the δ¹⁸O and δ¹³C (‰) composition points in carbonatite breccia fragments and in the interfragmentary space form a trend with high correlation, which is similar to the trend of mixing of C and O isotopes of carbonatites and sedimentary carbonates. However, it contradicts the data on the increasing contents of REE, Nb, P, and other elements typomorphic for carbonatites with increasing δ¹⁸O and δ¹³C (‰) values and is the result of the transformation of carbonates by a low-temperature deuteric fluid. The first obtained comprehensive data on carbonatite breccias give grounds to consider them a new type of mineralization in the TC.

We present new data on high-Ba phlogopites first discovered in kimberlite of the Malokuonapskaya pipe. The studied phlogopites can be divided into two groups: (1) megacrysts up to 2 mm in size with a BaO content of up to 0.58 wt.%, characterized by an increase in the content of this component from core to edge (with direct zoning for BaO), and (2) zoned crystals up to 200 μm in size, containing inclusions of minerals of the kimberlite groundmass, with a BaO content of up to 14.6 wt.% in the cores, regularly decreasing to 1 wt.% toward the edges. The two generations of mica formed in different and unrelated processes. Crystallization of megacrysts took place at the earliest stages of the evolution of kimberlite melt. The slight increase in Ba content from the core to the edges of phenocrysts might be the result of the evolution of kimberlite melt leading to its enrichment in incompatible elements. Phlogopites of group 2 formed at a later stage, together with the groundmass minerals. High Ba contents in these phlogopites are possible in the case of the strong enrichment of the kimberlite melt with light elements. The refertilized lithosphere under the influence of the Siberian traps might have been the source of these elements. ⁴⁰Ar/³⁹Ar dating of the phlogopite yielded an age of 232.1 ± 2.6 Ma.

This paper presents new geochronological and paleomagnetic data that support the idea of later termination of magmatism in the Okhotsk-Chukotka Volcanic Belt (OCVB) within the East Chukotka flank zone than previously thought. It also allows the calculation of a new paleomagnetic pole (78.6°N, 212.2°E, A₉₅ = 4.7°, N = 104) with an age of ~72 Ma for the vicinity of the Valunistoe deposit. Combined with paleomagnetic data previously obtained by us for the Kupol deposit area, the new results lead to the following conclusions: 1) the studied areas (the Kupol and Valunistoe location) have experienced relatively small, but statistically significant, displacements relative to the North American plate during the time interval from the late Cretaceous to the present. 2) The Kupol location is rotated counterclockwise by several to a few tens of degrees relative to the North American plate, while the Valunistoe location is displaced relative to this plate in latitude by a distance of at least several hundred kilometers. 3) Based on the obtained data, we propose a model, building on the existing Bering Sea region model of Redfield and Fitzgerald [1993], according to which the Kupol and Valunistoe locations belong to the boundary area between the North American plate and the Bering plate, represented by a series of tectonic blocks. The tectonic block to which the Valunistoe location belongs is one of the westernmost blocks grouped into the Bering plate, while the Kupol location belongs to the easternmost regions of the Chukotka deformed margin of the North American plate. Deformations arising in the interaction of these tectonic blocks in the region under consideration are mainly diffuse. The Trans-Bering Seismic Belt appears to be a potential area where the discussed deformations may be most concentrated.

The paper presents the results of the study of the role of environmental factors (abiotic and microbiological) in the formation of groundwater quality in the river bank filtration zone under cyclic freezing/thawing (CFT). Groundwater samples from the Tunguska field (Priamurye) taken in the fall period from different aquifer depths from wells located at different distances from the river bank filtration zone were used. CFT was performed in vitro in the presence of different carbon sources at two temperatures: slow thawing from -18 °C to +4 °C; rapid thawing from -18 °С to +23 °С. The activity of microbial communities (MC) from groundwater and river water after CFT was confirmed by their ability cultured on a readily available carbon source (peptone) and hard-to-mineralize sodium humate (HNa), as well as under conditions of their co-metabolism. Maximum activity after CFT at a thawing temperature of 4 °С in the presence of HNa was shown by MC from a depth of 41 m from boreholes 1500 m away from the shore. At a thawing temperature of 23 °С, microorganisms from river and groundwater from wells close to the shore were highly active regardless of the composition of carbon sources during the CFT period. MC growth activity from offshore wells at 23 °С thawing temperature was dependent on the depth of water sampling and the presence of readily available co-substrate. It was shown for the first time that after CFT, thawing temperature influenced the changes in the spectral characteristics of humic substances as a result of their microbial transformation

Herbs layer aboveground phytomass of the association Trollio asiaticae - Populetum tremulae (absolutely dry weight) and its species structure was determined. It was found that from 37 collected species two dominant species made 80 % of total phytomass. Moreover, only five species have more than 1 % of total phytomass each and the rest of species cover only 6,7 %. Comparison with published data about phytomass of the different layers and fractions of plant communities showed that phytomass of the herbs layer is equal or even more than photosynthetically active phytomass of the tree layer. So, in this ecosystem there are two equal layers of photosynthetic activity - herbs layer and tree layer.

This article examines the problem of environmental adaptations of plants to the conditions of the supralittoral and littoral of the Barents Sea coast. The article is devoted to a comprehensive study of the anatomical features of the leaf blades Honckenya peploides (L.) и Cochlearia officinalis (L.). The study used plants collected in the budding phase. The collected leaves were fixed in 70 % ethanol. Measurements of the elements of the anatomical structure were carried out using a light microscope. It has been established that the environmental conditions of the coastal zone determine the formation of specific anatomical features in these plants. H. peploides is characterized as a more highly specialized species with pronounced xeromorphic features: amphistomatic leaves, a developed cuticle layer and an isolateral mesophyll structure. C. officinalis is a heterogeneous species. In supralittoral conditions, the plant exhibits mesomorphic features such as sinuous cell walls, hypostomatic leaves, clear differentiation of the mesophyll into columnar and spongy layers, as well as the presence of large intercellular cells in the spongy mesophyll. On the upper littoral, C. officinalis acquires xeromorphic features: an increase in the thickness of the leaf and cuticle, as well as amphistomaticity. Probably, the combination of meso- and xeromorphic features favored the distribution of C. officinalis in a wider range of the coastal zone. The data obtained confirm the close connection of the anatomical structure of the leaves with environmental conditions and reflect the specific adaptations of each species to the environment.

Rare endemic plant species are most sensitive to changes in ecosystems, which can negatively affect the state of populations. The study of various ecological parameters in natural locations is most important for their monitoring and conservation. Megadenia bardunovii is a relic species of the Tertiary period vegetation with a restricted area. In Russia, two small populations are known in the Tunka Valley (Republic of Buryatia). In this work, the composition of water and soil in the natural location, the area of populations, phylogenetic relationships were studied, an introduction experiment and seed reproduction assessment were carried out. The confinement of populations to freshwater springs and loose, fertile sod-carbonate soils was revealed. It was shown that the populations occupy an area of 408 and 564 mІ. Seed germination is low, vegetative reproduction predominates. Analysis of nuclear (ITS) and chloroplast (rbcL, matK, trnL-trnF, trnH-psbA) markers revealed the absence of genetic diversity in the two studied populations. Analysis of chloroplast DNA showed that the populations from the Tunka Valley represent a separate evolutionary lineage, significantly different from all other Megadenia populations in China and the Russian Far East. The introduction experiment showed that an adult individual is a perennial creeping-root polycarpic plant and consisting of a complex of rosette shoots formed from adventitious buds on roots. In the introduction experiment, the morphometric parameters of plants were close to those in situ. Under cultural conditions, the species is of medium promise for introduction and has average resistance during long-term cultivation; it does not withstand competition from other species. Biological features determine the species strategy - rapid capture of territory using adventitious buds on the roots. The studied populations can be characterized as relatively stable under existing conditions. The developing and maintenance of a reserve fund is relevant. The obtained results supplement the data on the ecology and biology of the species and determine the parameters for monitoring and preserving the species in natural habitats.

The paper considers meadow and saline wormwoods, which constitute an original element in the vegetation of intrazonal landscapes of river valleys and intermountain depressions of Buryatia. They are represented by both typically saline Central Asian (with Artemisia schrenkiana, A. nitrosa) and meadow both East Asian (with A. selengensis), and Holarctic (with A. vulgaris, A. mongolica). According to phytocenotic confinement, it is necessary to note the contrast of ecological conditions in the floodplain-terrace complexes of the Dzhida River and saline depressions in the Ivolga valley, reflected in the composition and structure of plant communities. Thus, meadow, meadow-shrub communities on the Dzhida terraces are distinguished by a high projective cover (up to 80 % and more), often have a thicket character with an abundance of A. selengensis. The floristic composition of the communities is characterized by North Asian and South Siberian elements (Achnatherum sibiricum, Potentilla tanacetifolia), and in the group of specific species, East Asian ones - A. selengensis, Ribes diacantha. Phytocenoses of the saline vegetation of the Ivolginskaya valley have a low projective cover of grass - at the initial stage of vegetation 30 %, by mid-summer, in the phase of the beginning of flowering, the participation of wormwood reaches 60 % or more. In terms of floristic composition, the communities are poor and monotonous (up to 14-17 species on test sites). They are composed by the desert-steppe Central Asian elements - Achnatherum splendens, Plantago salsa, Artemisia nitrosa, as well as Eurasian saline-steppe species - Limonium gmelinii, Saussurea amara and others. The studied wormwoods of Buryatia have in common the absence of α-thujone and zingeberene in the essential oils, unlike the same species from other regions. The fact of division of wormwood essential oils by belonging to the subgenera Artemisia (A. vulgaris, A. selengensis) and Seriphidium (A. schrenkiana, A. nitrosa) was revealed. Due to their anti-inflammatory and antioxidant properties, wormwood essential oils can be used to treat cardiovascular diseases, digestive disorders, Alzheimer’s disease, and acute respiratory diseases.

This study is devoted to the assessment of pine plants of urban and suburban plantings in Moscow and Beijing in order to diagnose the adaptation of three pine species (Pinus sylvestris L., P. mugo Turra and P. tabuliformis Carr.) to abiotic stress occurring in urban environments. Non-invasive biochemical measurements of pine needles using Raman spectrometry (Raman microscopy-spectroscopy), allowed us to register changes in their biochemical composition that are not yet manifested externally. The accumulation of carotenoids, anthocyanins and polyamine spermine was observed in the needles of P. sylvestris under prolonged abiotic stress (anthropogenic air pollution). The observed response of pine plants to in vivo stress was further confirmed by common destructive chemical extraction methods. The accumulation of macro- and microelements was observed in the needles of P. sylvestris growing on the territory with maximum anthropogenic load compared to background values: maximum levels of Fe, Cu, Mn, Cr, Cr, Ni, Ag, Pb, Ba and Cd exceeding background values by 2.7-23.5 times. The analysis of Raman spectra allows us to recommend the method of microsopy Raman spectroscopy for high-throughput stress phenotyping of urban pine plantations. The ranking of the analyzed species by resistance to urban conditions resulted in the following series Pinus tabuliformis → Pinus sylvestris ≈ Pinus mugo.

The article presents an analysis of pollution of surface waters of the middle reaches of the Gazimur River by heavy metals in the area of the Bystrinsky mining and Processing Plant (Zabaikalsky Krai, Russia). Plants have been studied as indicators of pollution: Fontinalis antipyretica Hedw, Ranunculus circinatus Sibnt., filamentous algae - Cladophora fracta (Müll. ex Vahl) Kütz. and Ulothrix zonata (Web. et. Mohr) Kütz., from fish - Rhynchocypris lagowskii (Dybowski, 1869), which are the most common macroscopic hydrobionts in the studied area. Heavy metals (HM) in water and hydrobionts were determined by atomic emission and mass spectral analysis methods. It was found that the values of the TM concentration in the studied organisms were close to the values from the watercourses of other regions of the Trans-Baikal Territory. At the same time, high concentrations of TM in the aquatic moss of F. antipyretica were detected for the watercourses of the Gazimur river basin, which was confirmed by calculating the coefficient of biogeochemical activity of the species. The calculation of the total pollution index in the indicator species showed that F. antipyretica has high values for rivers draining catchments with mining sites. For Rh. lagowskii, the highest coefficient values were determined in watercourses remote from mining areas. The results of water biomonitoring studies using hydrobionts make it possible for them to be constantly included in routine monitoring of the state of aquatic ecosystems along with existing hydrochemical monitoring of surface waters. In the future, attention should be paid to comparing the cumulative properties of aquatic plant species with other aquatic organisms to monitor the spread of TM pollutants through trophic chains.