We present zircon U-Pb age and Lu-Hf isotope data, as well as biotite 40Ar/39Ar age, for metamorphic rocks from the Tulovchikha Formation in the northeastern Bureya Massif, Central Asian Orogenic Belt. Our results show that this formation contains metamorphic rocks of various ages: amphibolites and gneisses with protolith ages of 767 +/- 2 and 469 +/- 1 Ma, respectively. The amphibolites formed as a result of metamorphism of Neoproterozoic intermediate rocks with suprasubduction signatures and positive epsilon Hf(t) values (+3.0 & mldr;7.7), indicative of a mantle source. We suggest that the formation of these intermediate rocks occurred in a subduction setting at the margin of Rodinia. The age of the superimposed metamorphic overprint on the amphibolite protoliths is constrained by U-Pb dating of zircon grains exhibiting unambiguous metamorphic textures, yielding an age of 529 +/- 26 Ma. We suggest that this metamorphic event is related to the final amalgamation of Gondwana, linked to subsequent deformation or the initial stages of breakup of this continent. The gneisses were formed from Ordovician acidic igneous rocks. Their zircon epsilon Hf(t) values -4.7 & mldr;+3.4, which yield tHf(C) model ages of 1.5-1.0 Ga, indicating they formed by melting of heterogeneous Mesoproterozoic crustal sources. This event was likely related to interactions between the Bureya-Songnen and Jiamusi-Khanka massifs in a subduction-collision-post-collisional extensional setting. In addition, there were localised thermal overprints at 258 +/- 4 and 225 +/- 4 Ma, based on biotite 40Ar/39Ar dating. These thermal events might have been related to either deformation of the Bureya Massif during the late stages of closure of the Paleo-Asian Ocean or back-arc extension resulting from subduction of the Mongol-Okhotsk oceanic plate beneath the margin of this massif.

Alumina - 7.5 wt% yttria-stabilized zirconia (YSZ) ceramic composites were sintered using 24 GHz microwave heating at rates of 10 - 200 degrees C/min with zero isothermal hold. The starting powders were nanophase i-Al2O3 and YSZ prepared by a laser evaporation method. The final densities of the sintered samples were up to 97.5 % of the theoretical value. The samples exhibited rapid densification until transformation to the alpha-Al2O3 phase. The temperature of the densification rate peak (and hence of the phase transformation) decreased consistently with increasing microwave electromagnetic field intensity (varied by using different susceptor materials). The densification peak temperature difference between microwave and conventional sintering experiments exceeded 200 degrees C.

Sheveluch is one of the most active volcanoes in Kamchatka. Its modern edifice includes three main elements: Old Sheveluch, an ancient caldera and Young Sheveluch. On the southeastern slope of Old Sheveluch, there is a group of ancient extrusive domes (from south to north): Sherokhovataya, Krasnaya, Karan, and Sopochka na sklone. Only in the area of the Karan dome are there heated areas with mofets temperature of 70–96°C. After the powerful explosive eruption of the Sheveluch volcano in April 2023, the gas–steam activity of the Karan dome intensified, and a thermal anomaly began to be noted in satellite images of the area of this dome. On April 26, 2024, in a JPSS‑1 satellite image at 15:07 UTC, Kamchatkan Volcanic Eruption Response Team scientists discovered a bright thermal anomaly in the area of the Karan dome; that is, they recorded a unique phenomenon on this day: the birth of a new volcanogenic formation—the new lava dome. It was given the name 300 Years of the Russian Academy of Sciences. As of June 7, 2024, the size of the new dome was 800 × 500 m and the area of the dome crown was 0.19 km2. The eruption of the new lava dome 300 Years of the Russian Academy of Sciences is continuing.

The Heihe-Nenjiang suture zone, which is one of the major sutures in the eastern Central Asian Orogenic Belt, occurs between the Xing'an and Songnen-Zhangguangcai Range massifs and extends from southern Mongolia via northeastern China into eastern Russia. The amalgamation history of these massifs is controversial, especially for that during the late Paleozoic. Here we report whole-rock geochemical and zircon U-Pb geochronological data for two granite intrusions in the northeastern Heihe-Nenjiang suture zone with the aim of constraining the emplacement timing and their tectonic setting. In addition, combined with our previously published data for the Russian part of this suture zone, we compare tectonic processes between the two regions. We identified two monzogranites dated at 313 +/- 3 and 307 +/- 3 Ma, and a hornblende-biotite granite dated at 306 +/- 2 Ma. The ca. 313 Ma and ca. 307 Ma monzogranites contain annite and have geochemical affinity to A2-type granites. The geochemistry of the ca. 306 Ma hornblende-biotite granite, and the presence of edenite, pargasite, and siderophyllite, indicate it is an I-type granite. These late Carboniferous A(2)- and I-type granites in the Russian part of the Heihe-Nenjiang suture zone formed during a 313-295 Ma magmatic event, which include 306 +/- 4 Ma monzogranites, 301 +/- 4 Ma rhyolites, and 295 +/- 4 Ma plagiogranites with an adakitic signature. These rocks are all related to the post-collisional extension setting after the amalgamation of the Xing'an and Songnen-Zhang-guangcai Range massifs.

Eastern Asia experienced large-scale Mesozoic magmatism and contains numerous ore deposits related to late Mesozoic magmatism. In this paper, we report whole-rock geochemical and Ar-40/Ar-39 geochronological data for the host igneous rocks of the Ikan, Elnichnoe, and Vostochnyi Dvoinoi porphyry Au - Cu-(Mo) deposits in the northeastern Erguna Massif, Russia, to establish the age of late Mesozoic magmatism and mineralization, and its tectonic setting. The deposits record three Early Cretaceous magmatic events with ages of 142-125, 123-113, and 110-100 Ma, which correspond to regional magmatic events in the Great Xing'an Range in northeastern China. The studied igneous rocks are dominantly calc-alkaline and are similar to adakites in association with Early Cretaceous intrusions and volcanic rocks. Enrichments in large-ion lithophile elements and depletions in high-field-strength elements indicate an active continental margin tectonic setting. The magmatic events at 142-125 and 123-113 Ma were associated with Au - Cu-(Mo) mineralization. There is a significant time gap between Early - Middle Jurassic closure of the Mongol - Okhotsk Ocean and the Early Cretaceous magmatic/mineralization events. We suggest that the studied Early Cretaceous porphyry ore deposits were related to large-scale delamination of thickened lower crust and lithospheric mantle or intracontinental extension related to lithospheric thinning that resulted from subduction of the Palaeo-Pacific oceanic slab. Slab break off environment might also have contributed to the formation of the Early Cretaceous ore deposits.

In this paper, a procedure for estimating local fractal dimensionality values for greyscale images was developed. This procedure was tested on synthesised fractal and multifractal Brownian surfaces. The use of the method of detrended fluctuation analysis to determine the Hurst index for samples with a size not exceeding 2000 points was analysed. The optimal values of the sample size and the scale parameter have been obtained, allowing the Hurst index to be calculated with an error of less than 20%. The procedure was also tested on greyscale images, which are 8-bit representations of a synthesised fractal surface. The peculiarities of the application of the procedure for calculating the local fractal dimension for images obtained by scanning electron microscopy have been analysed. The values of the local fractal dimension of the oxide support MgAl2O4 are calculated using SEM images at different magnifications. It has been shown that, taking into account the fractal dimensionality calculation, different morphologies of the particle surface are observed at different scales of image magnification. At the highest magnification, the particle surface is found to consist of embedded smooth micron particles. The surface morphology of the MgAl2O4 particle depends on the micro- and mesopores between the embedded particles, this surface can be characterised by a fractal surface with FD2 = 2.3-2.4.

A model has been developed for the deposition of rare earth elements with yttrium, trace elements, and nonferrous metals in platform and activated structures of the Upper Amur region. Genetic types of lanthanide enrichment are considered; lanthanides are shown to concentrate nonuniformly in coal seams and in coal combustion products. Light rare earth elements predominate in coals. The capacity of peat and coal for metal extraction from aqueous solutions was proven. Criteria for a preliminary assessment of coal as a raw material for lanthanides were considered and prospects for their identification were analyzed.

Samples of alumina - 3 % yttria-stabilized zirconia (YSZ) composites were sintered in rapid processing regimes using 24 GHz microwave heating at rates of up to 200 degrees C/min and zero hold time. The final relative density was 96-99 % for the samples containing 1.5 and 7.5 wt % YSZ and 98-99 % for the samples containing 13 wt % YSZ. The microwave sintering kinetics were compared for the processes carried out by direct and susceptor-assisted microwave heating. Under direct microwave heating, the effect of an intense microwave electromagnetic field with an estimated absorbed power density of up to 130 W/cm(3) resulted in a shift of the shrinkage curves by about 100( degrees )C towards lower temperatures compared to the case of susceptor-assisted heating. The grain size of the samples sintered by direct microwave heating decreased with an increasing heating rate. The mechanical properties were slightly higher for the materials sintered under susceptor-assisted microwave heating. The samples containing 13 wt % YSZ exhibited a microhardness of about 20 GPa and a fracture toughness of about 7 MPa m (1/2) .

The paper presents the results of geochemical and Sm-Nd isotopic-geochemical studies of metavolcanic rocks of the Djagdagle formation of the northwestern part of the Bureya continental massif. As a result of reconstruction of the primary composition of the metavolcanic rocks, the correspondence of their protoliths to the pantelleritic, comenditic rhyolites is shown. Nd-features of metavolcanic rocks of the Djagdagle formation indicate the melting of rocks of continental crust with Paleoproterozoic model ages during the formation of their initial melts. Geochemical features, close spatial position with Mongol-Okhotsk orogenic belt allow us to link the formation of initial melts of metavolcanic rocks of the Djagdagle formation with within-plate magmatism in the rear zone of subduction of the Mongol-Okhotsk Ocean beneath the northern (in modern coordinates) margin of the Bureya continental massif.

Experiments were carried out on the treatment of the W – C – Co system nanopowders obtained by plasma chemical synthesis in a microwave electromagnetic field with a frequency of 2.45 and 24 GHz in different gas media. The effect of treatment time, power input and carbon content in the treated nanopowder on the yield of tungsten monocarbide WC was investigated.

There is general agreement that a series of East Asian blocks has always lain outboard of both India and Australia along the North Indo−Australie peripheral orogen. However, whether the East Asian blocks were involved in the interior orogens of East Gondwana remains equivocal. The geochronology and geochemistry of Neoproterozoic−Late Triassic rocks in the Russian Far East, together with existing paleontological and detrital zircon data, offer an opportunity to determine the tectonic origin and drift history of the Bureya−Jiamusi−Khanka superterrane. Biotite and amphibole 40Ar/39Ar dating results define a distinctive episode of Late Pan-African (ca. 550 Ma) metamorphism and a local Late Triassic (ca. 219−200 Ma) episode of deformation for the Bureya−Jiamusi−Khanka superterrane. Zircon U−Pb ages and whole-rock geochemical data indicate that the Early Ordovician (483 ± 3 Ma) highly fractionated I-type monzogranites were emplaced in a post-collisional setting linked to the collapse of a Late Pan-African orogen, while the Late Triassic (ca. 234−223 Ma) A-type quartz syenites and I-type granite aplite dikes were formed in a slab-pull−induced passive continental margin of the subducting Mudanjiang oceanic plate. These crucial archives, complemented by data from the literature, reveal that the Bureya−Jiamusi−Khanka superterrane made up the northernmost Kuunga-Pinjarra interior orogen during the final assembly of East Gondwana. As a result of Devonian rifting after Early Ordovician orogen collapse, the Bureya−Jiamusi−Khanka superterrane escaped from the Kuunga-Pinjarra interior orogen and subsequently migrated to Northeast Asia by the Late Triassic to Jurassic due to the subduction and closure of the Paleo-Tethys and Paleo-Pacific oceans.

4 Дальневосточный центр НИЦ «Планета»

The paper presents the results of U–Pb (ID-TIMS) geochronologic, geochemical, Sm–Nd isotopic-geochemical studies of metavolcanic rocks of the Djagdagle formation, which are among the key elements in the structure of the Bureya continental massif. It was established that the age of metavolcanic rocks of the Djagdagle formation is 217 ± 7 Ma and corresponds to the Late Triassic. This fact contradicts the traditional ideas, according to which the Early Precambrian age is attributed to the Djagdagle formation. The results of Sm–Nd isotope studies of the considered metavolcanic rocks indicate the melting of rocks of continental crust with Paleoproterozoic model ages during the formation of their initial melts. The new geochronologic data and previously published data allow us to distinguish at least two stages of magmatic activity in the Triassic within the northwestern part of the Bureya massif ~243 and 219–201 Ma. On the basis of synchronous manifestation of Neoproterozoic, Early Paleozoic, Late Paleozoic and Early Mesozoic magmatic events in the history of geologic development of the Bureya and Songnen– Zhangguangcai Range massifs, an assumption about their common geological history at least since the Late Neoproterozoic has been put forward. The close spatial position of metavolcanic rocks of the Djagdagle formation with Mongol–Okhotsk orogenic belt, their Late Triassic age (217 ± 7 Ma) and geochemical features allow us to link the formation of initial melts of metavolcanic rocks of the Djagdagle formation with within-plate magmatism in the rear zone of subduction of the Mongol–Okhotsk Ocean beneath the northern (in modern coordinates) margin of the Bureya continental massif.

The Sheveluch volcano is the most active volcano in Kamchatka. The paroxysmal explosive eruption of the volcano that destroyed the lava dome in the volcanic crater continued on April 10–13, 2023. According to various satellite data, the height of the separate eruptive clouds probably exceeded 15 km above sea level. A powerful cyclone, which dominated the entire Kamchatka Peninsula, pulled the eruptive cloud to the west, turned it to the south, stretched it to the north, and directed it to the east from the volcano. The dynamics of the development of ash and aerosol clouds of this eruption is reflected in the animations made from a series of Himawari-9 satellite images in the VolSatView IS from 08:00 UTC on April 10 to 07:00 UTC on April 14 ( http://d33.infospace.ru/jr_d33/materials/2023v20n2/283-291/1683110898.webm ) and of the Arctica-M1 satellite from 16:00 to 21:30 UTC on April 10 ( http://d33.infospace.ru/jr_d33/materials/2023v20n2/283-291/1683821166.webm ). It was noted that the eruptive column was not vertical: for example, at the initial moment of the eruption on April 10 at 13:20 UTC, it deviated to the north–northeast; on April 11, at 12:00 UTC to the northwest; and, on April 12, at 7:00 UTC to the southwest. During the paroxysmal eruption, sulfur dioxide continuously entered the atmosphere, the maximum amount of which was released on April 10–11, as a result of the explosive destruction of the lava dome of the Sheveluch volcano. Ash clouds along with aerosol clouds on April 10–13 were stretched into a strip more than 3500 km long from west to northeast. On April 21–22, the Sheveluch aerosol cloud was observed in the region of the Scandinavian Peninsula. The total area of the territory of Kamchatka and the Pacific Ocean where ash and aerosol plumes and clouds were observed during the April 10–13 eruption was about 3 280 000 km2. The paroxysmal eruption of Sheveluch volcano belongs to the sub-Plinian type because it is characterized by a large height of the eruptive cloud and a long event duration. For this eruption, the Volcanic Explosivity Index is estimated to be 3–4. A detailed description of the paroxysmal explosive eruption of the Sheveluch volcano and the spread of the eruptive cloud was performed based on data from various satellite systems (Himawari-9, NOAA-18/19, GOES-18, Terra, Aqua, JPSS-1, Suomi NPP, Arctica-M1, etc.) in the information system “Remote Monitoring of Kamchatka and Kuril Islands Volcanic Activity” (VolSatView, http://kamchatka.volcanoes.smislab.ru ).

The results of U–Th–Pb geochronological studies of zircons from metamorphic rocks of the Amur group of the Synchuga Block of the Jiamusi continental massif are given. It is shown that garnet–biotite–sericite schists of the Amur group have a primary sedimentary origin. The lower depositional age of the protolith can be determined by the age of the youngest zircons from a group with Neoproterozoic ages of 832 Ma. The upper age boundary of the protolith, apparently, corresponds to the age of metamorphic zircons of 533 Ma. Thus, the schists of the Amur group of the Synchuga Block are Neoproterozoic in age rather than Early Precambrian, as was accepted earlier.

The occurrence forms and location features of rare-earth elements in Miocene brown coals have been studied at the Sergeevskoe deposit (Amur region). Humic acids have been found to be concentrators of lanthanides, yttrium, and scandium in the Miocene brown coals. Rare-earth elements in the fraction related to humic matter reach 90 wt %, except for scandium which is 74 wt %. Scandium is 22 wt % in aluminosilicate minerals (clayey varieties, etc.). Lanthanides and yttrium do not exceed 5 wt % of the total in the ion-exchangeable, silicate, and disulfide forms. According to the electron microscopy results, the mineral part of the coal is represented mainly by barely soluble phosphate minerals. The coals of the Sergeevskoe deposit can serve as an easily enriched source of rare-earth elements.

Using the method of sintering by microwave heating at a rate of 10–100°C/min to a temperature of 1250 °C without isothermal hold, we obtain ceramic samples with the composition Ba0.75Sr0.25TiO3. The experiments are performed on a gyrotron complex for the high-temperature microwave treatment of materials, which is operated at a frequency of 24 GHz with a maximum power of 5 kW. The features of the formation of a solid solution in the sintered samples are analyzed. The dependence of the intensity of recrystallization growth of grains on the microwave-heating rate during the sintering is demonstrated. The permittivity of the samples obtained by microwave sintering with heating rates of 10 and 30 °C/min amount to 3600–4400 in the frequency range 25Hz–3MHz at room temperature.

Работа посвящена оценке возможности применения искусственных нейронных сетей для поиска ковулканических ионосферных возмущений во временных рядах полного электронного содержания, полученных по данным ГНСС-наблюдений.На примере извержения влк