The distribution of lithium deposits and lithium resources contained in them are analyzed throughout geological time. The basis for the analysis is data on 164 deposits from around the world with resources estimated above 100 thousand t of Li2O, representing almost the entire explored resource base attractive in the modern and near future conditions to extract this element. The variability of various aspects of their formation in geological time is demonstrated by comparing supercontinent cycles in terms of the quantity and quality of resources in deposits of different types, ages, and tectonic position. It has been established that lithium deposits have an extremely uneven pulsed distribution on the geological time scale. The Kenoran, Columbian, and Rodinian cycles are represented only by the pegmatite-type deposits, the intensity of formation of which decreased in this series. In the Pangean cycle, it increased again, approaching the Kenoran level. In addition, first deposits of a granite type appeared. In the current Amasian cycle, deposits of the granite type quantitatively predominate over the pegmatite type, but they both yield quantitatively to the clay-type deposits only appeared in this cycle. In terms of the resources, all these three types with solid ores are inferior to deposits associated with brines in salars, geothermal and oil-and-gas fields. All deposits from the Kenoran to Pangean cycles were formed in collision belts at the postorogenic stage of their development. In the Amasian cycle, continuity in this aspect was preserved, but deposits of granite and clay types formed in the back zones of active continental margins were also established. Deposits in salars also have these two tectonic positions. Geothermal deposits are known within the framework of collisional orogens and on active continental margins. Oil-and-gas fields have been explored only in the sedimentary covers of ancient platforms. Currently, objects of pegmatite and salar types are of maximum importance for the world economy, and the granite-type deposits are of less significance. All of them are traditional for lithium extraction. In the pegmatite type, the Kenoran deposits have the highest degree of industrial development, in the granite-type deposits of the Amasian cycle. In recent years, single deposits of clay, geothermal, and oil-and-gas field types began to be involved in the exploitation, as well as representatives of the salar type with brine compositions that have not been suitable for conventional technologies.

In this work, we present the studies of structural phase transitions in FeSe 0.675 Te 0.3 S 0.025 crystals. The data obtained indicate a significant change in the behavior of many characteristics during the transition in this composition compared to the case of the unsubstituted FeSe. The resistivity at low temperatures for the studied FeSe 0.675 Te 0.3 S 0.025 is proportional to the square of the temperature, while for pure FeSe below the structural transition it depends almost linearly on temperature. 77 Se NMR studies also confirm a change in the type of phase transition. The NMR data showed a noticeable line broadening below the structural transition and an anomaly in the temperature dependence of the relaxation rate, which was not observed in FeSe. Our results confirm the quantum criticality of Fe(Se,Te) at a low Te content or existence of the nematicity change point (NCP). This makes the phase diagram of quasi-binary Fe(Se,Te) compounds generally consistent with the phase diagram of FeSe under pressure. In both cases, there is a local minimum in the superconducting critical temperature near NCP and a strong increase in the superconducting critical temperature near the point of complete suppression of nematicity.

Dmitry Vasilievich Rundkvist worked in the Vernadsky State Geological Museum of RAS from 1993 to 2021. Despite of being overloaded with managerial issues as the museum’s director (1993-2003) and as academician-secretary of the Earth’s Sciences Department of RAS (1996-2003), he had contributed a lot in metallogenic researches. The article describes this period of the Rundqvist’s life, focusing on major results of his metallogenic studies and on their further development in the museum.

The paper presents the results of analyzing uranium content in man-made carbonates (scale crusts) on the territory of Ufa based on examination of 42 samples. The median uranium content in the investigated samples stands at 1.44 mg/kg, which is significantly lower than the background values (scales from the Lake Baikal water, a clarke of sedimentary carbonate rocks) and data on other settlements of the Republic of Bashkortostan. Low values of uranium content are probably associated with the effects of the three leading factors, i.e. specific subsurface geology of the territory (gypsum, limestone); types of water supply; water treatment processes for the centralized type of water supply. Spatial distribution of uranium in man-made carbonates is characterized with uniformity, which is disturbed in two cases, i.e. a change of the water supply type (from centralized to individual); and material of the vessels used for boiling the water. No significant differences were detected when comparing samples of man-made carbonates associated with different sources of water supply (the bucket and infiltration types of water intake) and the types of household filters.

This paper reports on lithium metallogeny in geological time. The geochronological analysis was conducted on the basis of data on 71 lithium deposits distributed globally. These deposits contain almost all Li resources, which are industrially significant and of potential interest in terms of the economy. It was established that these deposits were formed in different geological epochs, from the Late Mesoarchean to the Holocene. The distribution of their resources on the scale of geological time is distinctly discrete. In the Kenoran, Columbian, and Rodinian supercontinent cycles, only pegmatite deposits of lithium were formed. In the Pangean cycle, the main resources are also attributed to pegmatite deposits, but some of them are concentrated in lithium–fluorine rare-metal granites. In the incomplete Amasian cycle, salars of geodynamically active areas play a main role in the resource base; the epithermal stratiform deposits, pegmatites, and lithium fluorine-granites are of much less significance.

In this paper, we present a protocol designed to avoid typical problems occurring in the process of the spatial spin modulated structure (SSMS) investigation in BFO-based (BiFeO3) materials by zero-field nuclear magnetic resonance (ZF NMR) spectroscopy on Fe-57 nuclei. We have analyzed the significant discrepancies in the parameters of the spectra in the literature and developed the measurement protocol to improve the quality and unify the obtained spectra. The study of the Fe-57 spectra of Sr-doped BFO at 4.2 K samples was carried out to illustrate the protocol. The obtained spectra demonstrate suppression of the SSMS by heterovalent substitution. The Sr-concentration dependent evolution of the SSMS anharmonicity parameter was observed as well.

New geochronological (U–Pb ID-TIMS) data on zircons from pegmatites of the Mama mica belt in the Baikal Highlands are presented. The ages obtained for the plagioclase pegmatites (388 ± 2 and 389 ± 2 Ma, Mochikit deposit) and two-feldspar pegmatites (333 ± 1 and 332 ± 3 Ma, Slyudyanka deposit) demonstrate a significant age gap (50–60 Ma) between them. Based on the entire set of geological and new geochronological data available, it is proposed to divide the Mama complex, to which they were previously assigned, into two separate granitoid complexes.

This paper reports the results of analysis of the geophysical fields of a gold deposit and reveals some of their typical features. The range of geophysical studies and data processing techniques for solving the problems of gold mineralization forecast within the Yana–Kolyma Metallogenic Belt is described. Based on the interpretation of the geophysical dataset, the geological and geophysical indicators of gold mineralization are proposed in the following hierarchical sequence: ore cluster–ore field–mineralized zone–ore body. One of the main interpretation techniques for determining the prospecting indicators of potential ore bodies (or high-grade intervals) is the study of induced polarization frequency responses.

Three salts of perchlorinated sulfonium and ammonium derivatives of tetrabuthylammonium nonachloro-closo- decaborate, (n-Bu4N)(2)[2-B10Cl9-cyclo-S(CH2)(4)S-B10Cl9] (1), (n-Bu4N)[2-B10Cl9-cyclo-S(C2H4)(2)O] (2) and (n- Bu4N)[1-B10Cl9N(n-Pr-3)] (3) are synthesized and characterized using IR, B-11, H-1, C-13 NMR, X-Ray and Cl-35 NQRspectroscopy. The noncovalent interactions involving chlorine atoms were identified by Cl-35 NQR spectra. The results were discussed in comparison with those of X-ray diffraction analysis which are based on measuring contacts shorter than the sum of van der Waals (vdW) radii of atoms. It has been found that the crystal lattice of 2 exhibits dynamic properties strongly different from those of 1 and 3. Whereas the Cl-35 NQR spectra of the latters were extremely wide (up to 1200 kHz), the spectrum of 2 demonstrated a narrowing of almost an order of magnitude (up to 120 kHz) which indicated a significant weakening of the tendency for the formation of intermolecular bonds by chlorine atoms of this cluster.

Objective: to improve the assessment of activity of ulcerative colitis and the ability to predict the development of relapse of the disease, as well as the selection of adequate therapy.Materials and methods: the study included 90 people: 70 patients with ulcerative colitis and 20 healthy volunteers. The disease activity was evaluated using 7 disease activity indices. The expression of matrix metalloproteinase -9 (MMP-9) in the colon mucosa was evaluated by immunohistochemistry.Results: data were obtained on the activity of MMP-9 in colonobioptates in patients with ulcerative colitis with varying degrees of disease severity, which complements our knowledge of the pathogenetic mechanisms of UC and, based on the developed mathematical model, allows predicting the development of recurrence of UC. Based on the analysis of clinical indices of UC activity, an algorithm for evaluating the effectiveness of basic therapy has been developed.Conclusion: tools are provided to improve the prognosis of UC relapse, and a personalized approach to evaluating the effectiveness of the alternatives of drug therapy is developed.

The distribution of integrated resources of large and superlarge deposits (LSLDs) of rare earth elements (REEs) is compared to the current model of supercontinent cyclicity during Earth's evolution. It is found that REE LSLDs are related predominantly to igneous complexes (carbonatite, nepheline syenites, syenite-alkaline granites, subalkaline granites), which are often additionally enriched in the hypergenic zone. A certain part of the resources is concentrated in independent hypergenic formations represented by placers and ion-adsorbed clays. Each supercontinent cycle-Kenoran, Columbian, Rodinian, Pangean, and Amasian-is expressed in the REE metallogeny in particular way: we revealed significant intercycle variations in the amount of REE LSLDs, the variety of their types, total accumulated resources, and some other characteristics.

Tantalum metallogeny throughout the geological history is analyzed. The respective deposits are presented by five types (pegmatitic, granitic, alkaligranitic, foidic, and carbonatitic), which formed with varied intensity from the Late Mesoarchean to the Cenozoic. The largest amount of Ta resources is revealed in deposits formed during the Rodinian cycle; significant resources were also formed during the Pangean and Columbian cycles. These cycles are notable for the leading role played by deposits related to alkaline magmas of mantle origin. However, the most high-quality concentrates for Ta extraction are obtained at deposits in which ores are hosted in rare-metal pegmatites and Li–F granites related to crustal magmas. According to the estimates, the maximal amount of these resources is stored in deposits formed during the Kenoran cycle represented only by pegmatites.

The global distribution of tantalum deposits and their resources on the geological time scale is analyzed. The analysis is based on the data for 65 deposits of the world with a resource estimate from 2000 t of Ta2O5, which are classified into five types: pegmatitic, granitic, alkaligranitic, foidic, and carbonatitic. Placers and ore-bearing weathering crusts are taken into account with their bedrock sources. The variable features of the global metallogeny of tantalum are represented based on the comparison of the supercontinent cycle. It is established that the most significant resources in terms of quantity are confined in the deposits of the Rodinian cycle, among which the foidic type objects are fully dominant. Then, the descending order for the total resources is the Pangean and Columbian cycles, in which the main shares in the resources belong to the deposits of the alkaligranitic and foidic types. The Kenoran cycle, which lags behind them in its quantitative estimate, stands out in tantalum metallogeny by a monotype nature: only pegmatitic objects have created its resource potential. The current Amasian cycle is in the last place with respect to the total quantity of tantalum resources, which is explained to a great extent by its incompleteness. The resources of this cycle are distributed between the objects of the alkaligranitic, granitic, and pegmatitic types in comparable shares. It is noted that, due to their mineralogical features, the deposits of pegmatitic and granitic types make it possible to obtain the highest-quality concentrates and they are, therefore, of prime interest for tantalum extraction. The deposits of the pegmatitic types are known in all the cycles, while the deposits of the granitic type are known only in the Pangean and Amasian cycles. In total, they contain only one fifth of the estimated tantalum resources, and their major share accounts for the Kenoran and Pangean cycles.

Проанализировано глобальное распределение месторождений танталоносных руд и заключенных в них ресурсов тантала на шкале геологического времени. Основой для анализа стали данные по 65 месторождениям мира с ресурсной оценкой от 2 тыс. т Ta2O5, которые были классифицированы на пять типов: пегматитовый, гранитный, щелочногранитный, фоидный и карбонатитовый. Россыпи и рудоносные коры выветривания были учтены совместно с их коренными источниками. Вариативные особенности глобальной металлогении тантала представлены на основе сопоставления суперконтинентальных циклов. Установлено, что наиболее значительные в количественном аспекте ресурсы заключены в месторождениях родинийского цикла, среди которых абсолютно доминируют объекты фоидного типа. Далее, в порядке убывания суммарных ресурсов, следуют пангейский и колумбийский циклы, в которых главные доли в ресурсах имеют месторождения щелочногранитного и фоидного типов. Уступающий им в количественной оценке кенорский цикл выделяется в металлогении тантала монотипностью: только пегматитовые объекты создали его ресурсный потенциал. Текущий амазийский цикл стоит на последнем месте по общему количеству ресурсов тантала, что во многом объяснимо его незавершенностью. Ресурсы этого цикла распределены между объектами щелочногранитного, гранитного и пегматитового типов в сопоставимых долях. Отмечено, что из-за своих минералогических особенностей месторождения пегматитового и гранитного типов позволяют получать наиболее высококачественные концентраты и поэтому представляют первоочередной интерес для извлечения тантала. Месторождения пегматитового типа известны во всех циклах, а гранитного – только в пангейском и амазийском. Суммарно они заключают в себе только пятую часть оцененных ресурсов тантала, причем основная их доля приходится на кенорский и пангейский циклы.

Niobium metallogeny over the course of geological history has been considered on the basis of data from 45 largest deposits in the world belonging to any of three metallogenic types: alkaligranitic, foidic, and carbonatitic. The deposits were formed under variable intensity from the Middle Paleoproterozoic to the Cenozoic. The greatest resources of niobium are accumulated in the deposits formed during the Rodinian, Pangean, and Amasian supercontinent cycles. These cycles are characterized by the prevalence of deposits associated with carbonatite complexes.

The intensity of lithium accumulation through geological time has been analyzed. For this purpose we used the data on mineral deposits which have already exploited or potentially are of economic interest and which contain at least 0.1 × 10 tons of Li2O. Their formation was pronounced discrete and took place at various geological epochs from the Later Mesoarchean to Holocene. Each known supercontinent cycle differs in one way or another in the metallogeny of lithium. In the earliest cycles, Kenoran, Columbian, and Rodinian, exclusively pegmatite lithium deposits were generated. Moreover, this type is the only through one over the geological history, because such objects are also known in the Pangean and Amasian cycles. However, both the maximal number of such pegmatites and highest lithium grades are known for the oldest Kenoran cycle. This allows us to suppose that the Archean conditions were particularly favorable for lithium-bearing pegmatites. The lithium potential of the Pangean cycle also is mainly formed by pegmatites, except small part of resources related to lithium-fluorine (Li-F) rare-metal granites. The current Amasian cycle is far from the finish and the most diverse in types of lithium deposits. Pegmatites and Li-F granites in total contain only a tenth of the cycle’s resources. Known in the Miocene-Quaternary only, the epithermal stratabound deposits and especially lithium-bearing brines in salars play a main role in the cycle. In spite of the lowest lithium contents, exactly the last type gives the maximal part in total resources, as well in lithium extraction, due to the relative simplicity and efficiency of used extraction technologies.