Search

A unique feature of the Kamchatka Peninsula is an extensional structure running for more than 400 km along the peninsula—the Central Kamchatka Depression (CKD). Some geodynamic models associate the formation of the CKD with the movements of East Kamchatka toward the Pacific Ocean due to retreat of the northern edge of the subduction zone. However, isotope–geochronological data on the time of the CKD formation have been lacking up to the present time. Therefore, we could not directly associate the CKD emergence with the stages of the Kamchatka tectonic evolution and the intensity of its recent deformations. This work presents the chemical compositions and K–Ar ages of effusive rocks from the KL-1 borehole drilled in the northern part of the CKD. Samples from the depth interval of 50–475 m, represented by medium-K basalts and high-K basaltic trachyandesites date back to 0.7 to 1.5 Ma. By their composition, these rocks are close to effusive rocks forming the base of the Klyuchevskaya group of volcanoes. Before this study, the age of the effusives had been estimated as much younger, up to 0.3 Ma. Below, in the interval of 475–505 m, a pack of sands and boulder conglomerates was described. They unconformably overlap the aphyric and olivine–pyroxene porphyritic andesibasalts with interlayers of volcanic ash and volcanic sands of the same composition. At the depth of 905–1513 m, the borehole recovers highly altered tuffs, mafic and intermediate in composition, interbedded with andesites and andesibasalts. The K–Ar estimation of 3.5 ± 0.4 Ma was obtained for the least altered sample of medium-K andesibasalt from the depth of 1255 m. We suggest that the altered effusives at 905 m and below are associated with the completion of accretion of the Kronotskii Island Arc and with the formation of the modern structure of the Kamchatka Peninsula. The CKD setting occurred after this event in the interval of 1.5–3.5 Ma. [ABSTRACT FROM AUTHOR]

Marine fallout ash beds can provide continuous, time‐precise records of highly explosive arc volcanism that can be linked with the climate record. An evaluation of revised Plio‐Pleistocene (0–4 Myr) tephrostratigraphies from Ocean Drilling Program Sites 881, 882, and 884 confirms cyclicity of the Kamchatka‐Kurile arc volcanism and a marked increase just after the intensification of the Northern Hemisphere glaciation at 2.73 Ma. The compositional constancy of the Kamchatka‐Kurile volcano‐magma systems through time points to external modulation of volcanic cyclicity and frequency. The stacked tephra record reveals periodic peaks in arc volcanicity at ∼0.3, ∼1.0, ∼1.6, ∼2.5, and ∼3.8 Myr that coincide with maxima of the global ice volume variability that have been linked with the amplitude modulation of the precession (0.3, 1.0 Myr) and obliquity (1.6, 2.5 and 3.8 Myr) bands. A simple model of a decreasing obliquity variance across the mid‐Pleistocene Transition at constant precession variance produces an excellent correlation of ash bed cycles with the variability of global benthic δ18O (r2 = 0.75), which implies that climate, and not direct orbital forcing, modulates Kamchatka‐Kurile arc volcanism. The rising influence of precession variance in the Kamchatka‐Kurile ash bed record after the mid‐Pleistocene Transition contrasts with the dominant 100 kyr signal in the benthic δ18O global ice volume variability, which may either reflect limitations of the ash bed record or an regional rather than global influence of ice volume variability. Our results indicate that climate influences the Kamchatka‐Kurile arc volcanism, which may influence climate only by feedback. Plain Language Summary: Volcanic ash and dust produced during catastrophic explosive volcanic eruptions, such as those of Mount Pinatubo or El Chichón, can cause short‐term global cooling on the scale of a few years. It has long been speculated whether the Earth's long‐term cooling over the past few million years has been augmented by an increase in explosive volcanism about 2.58 million years ago. In order to investigate causal links between the climate evolution and volcanism during the past 4 million years, we obtained a time‐precise and temporally highly resolved record of the Kamchatka‐Kurile arc volcanism from the centimeter‐thick ash beds that were embedded in marine sediments after large eruptions downwind the volcanic sources. When the ash bed record is compared to climate evolution, it clearly shows that explosive volcanic eruptions—regardless of their short‐term effects—do not contribute directly to the long‐term global cooling. Instead, the variations of the Earth's powerful climate system modulate these explosive volcanic eruptions, as the periodic waxing and waning of the large ice shields affect the magma‐producing systems deep in the Earth's interior. However, climate‐active gases and particles produced during periods with more vigorous arc volcanism may still enhance the ice cycles. Key Points: Marine fallout ash beds record cyclicity and acceleration of the Plio‐Pleistocene (0–4 Myr) explosive Kamchatka‐Kurile arc volcanismAsh bed cyclicity correlates with the obliquity and precession variance of the global ice volumeClimate, and not direct orbital forcing, modulates the Plio‐Pleistocene volcanicity of the Kamchatka‐Kurile arc [ABSTRACT FROM AUTHOR]

The distribution of rare alkalis (Li, Rb, and Cs) is analyzed in spatially linked water objects of the Baikal geosystem: water of Baikal and its tributaries, underground water from boreholes and thermal springs, and the Angara River (the sole outlet), which are located in the Baikal rift zone. The rare alkali content differs significantly in some water objects, but the average and median contents are similar in the surface and deep water of Lake Baikal and the Angara River. The water of Barguzin thermal springs of the eastern shore of Lake Baikal contains the maximum amount of rare alkalis, but this affects the Baikal water insignificantly due to its natural self-cleaning and deep renewal of water during geodynamic movements. The similar rare alkali contents of Barguzin and some thermal springs of Kamchatka emphasize their indicator role in the genesis of water objects. [ABSTRACT FROM AUTHOR]

In 2020, in the caldera of Uzon volcano (Kamchatka Peninsula), electrical prospecting studies were carried out using the electrotomography method within the eastern thermal field near Shaman geyser. The geoelectric section is divided into three zones according to the level of electrical resistivity: relatively high-resistivity cold zones at the edges and a relatively low-resistivity hot zone in the center. The hot zone, situated at a depth of 5–20 m and hosting the Shaman geyser, is distinguished by anomalously low resistivity (less than 0.5 Ω m), which indicates the highest fracturing and saturation of rocks with fluid. Resistivity monitoring was carried out above the geyser using an Omega-48 electrical tomography station and two cables with lengths of 235 and 47 m. The first cable provided a survey depth of 60 m; the second, ∼12 m. Four phases of the geyser's operation are distinguished on the difference geoelectric sections, constructed from the monitoring results: filling, outpouring, spouting, and steaming in the form of alternating positive and negative electric field anomalies. The channel to the geyser was found from the results of areal measurements. [ABSTRACT FROM AUTHOR]

The isotopic signature (δ18О, δ2Н, d-excess) of the glacier ice in Ushkovskii volcano (Kamchatka Peninsula) was studied. A new shallow ice core was obtained in 2022 in the Gorshkov crater. The 14 m long ice core was dated by counting the annual layers, which were also compared with known eruptions in recent years. The upper 14 m of the glacier were formed over the last 16 years (from 2006 to 2022). The values of δ18О vary from −16 to −24‰, and the values of δ2Н, from −110.5 to −177.7‰, while the mean values are −20.5 and −150.2‰, respectively. The d-excess values vary with depth from 8.7 to 21.3‰ at a mean value of 13.7‰. For winter horizons at low values of δ18О and δ2Н, an increase in d-excess is noted. Such features are associated with the origin of moisture brought to Kamchatka. The source of moisture is the Pacific Ocean, the Sea of Okhotsk, and the Sea of Japan, for which there are pronounced differences in the conditions of moisture evaporation between summer and winter. The trends of increases in the δ18О and δ2Н values from 2006 to 2022 are accompanied by a decrease in the deuterium excess, indicating an increase in summer precipitation. However, in addition to changes in the seasonal proportions of precipitation, the d-excess values of ice may reflect climatic changes in the source of moisture. [ABSTRACT FROM AUTHOR]

Background: Microbial communities are important drivers of global biogeochemical cycles, xenobiotic detoxification, as well as organic matter decomposition. Their major metabolic role in ecosystem functioning is ensured by a unique set of enzymes, providing a tremendous yet mostly hidden enzymatic potential. Exploring this enzymatic repertoire is therefore not only relevant for a better understanding of how microorganisms function in their natural environment, and thus for ecological research, but further turns microbial communities, in particular from extreme habitats, into a valuable resource for the discovery of novel enzymes with potential applications in biotechnology. Different strategies for their uncovering such as bioprospecting, which relies mainly on metagenomic approaches in combination with sequence-based bioinformatic analyses, have emerged; yet accurate function prediction of their proteomes and deciphering the in vivo activity of an enzyme remains challenging. Results: Here, we present environmental activity-based protein profiling (eABPP), a multi-omics approach that extends genome-resolved metagenomics with mass spectrometry-based ABPP. This combination allows direct profiling of environmental community samples in their native habitat and the identification of active enzymes based on their function, even without sequence or structural homologies to annotated enzyme families. eABPP thus bridges the gap between environmental genomics, correct function annotation, and in vivo enzyme activity. As a showcase, we report the successful identification of active thermostable serine hydrolases from eABPP of natural microbial communities from two independent hot springs in Kamchatka, Russia. Conclusions: By reporting enzyme activities within an ecosystem in their native state, we anticipate that eABPP will not only advance current methodological approaches to sequence homology-guided enzyme discovery from environmental ecosystems for subsequent biocatalyst development but also contributes to the ecological investigation of microbial community interactions by dissecting their underlying molecular mechanisms. [ABSTRACT FROM AUTHOR]

The short-tailed albatross (Phoebastria albatrus) is a rare bird species today, numbers of which declined significantly in the Holocene due to human hunting activities. Bones of albatrosses from archaeological sites of Chukotka, Kamchatka, and the Aleutian Islands, and from coastal sediments of the Commander Islands were used to analyze the content of stable carbon and nitrogen isotopes in bone collagen. The analysis showed that the isotopic niches of Aleutian and Commander albatrosses diverged during the Holocene. Short-tailed albatrosses of the Aleutian Islands are closer to Holocene albatrosses of Vancouver Island (Canada) in the isotopic characteristics. [ABSTRACT FROM AUTHOR]

This study analysed long-term trawl survey data to investigate changes in the spatial distribution, range boundaries, and catch rates of the five most common shark species in the Russian waters of the northwestern Pacific. Significant alterations in the spatial distributions of these shark species were observed during the study period. The 1980s witnessed the most widespread distribution and maximum catches of salmon and blue sharks. In the 2000s, the North Pacific spiny dogfish exhibited its broadest distribution, with maximum catches recorded in the 1980s and 2010s. The Pacific sleeper shark exhibited its widest distribution in the 1980s, with maximum catches occurring in the 2000s. Shortfin mako were recorded within the study area only in the 1980s and 2010s, with maximum catches occurring in the latter period. Shifts in the range of boundaries during the study period exhibited different patterns among the species. Statistically significant shifts in boundaries were found for Pacific spiny dogfish, salmon sharks, and Pacific sleeper sharks. During the review period, salmon shark catches significantly decreased in Pacific waters and in the study area as a whole, but the reasons for this difference have not yet been determined. For the other shark species, statistically significant changes in catch size were not revealed. The observed significant changes in the spatial distribution and position of the boundaries of the ranges are likely due to both subjective reasons and climatic changes. [ABSTRACT FROM AUTHOR]

An aerobic, rod-shaped, non-motile, endospore-forming bacterium, strain V-9T, was found in the frozen volcanic ash, Kamchatka peninsula, Russia. Phylogenies based on 16S rRNA gene and genome sequences demonstrated that strain V-9T was affiliated with the family Paenibacillaceae and clustered outside the clade that includes the type species of this genus, Paenibacillus polymyxa, and closely related species. V-9T showed the highest 16S rRNA gene sequences similarity to Paenibacillus chartarius CCUG 55240T (96.7%). The similarity to type strains of other Paenibacillus species were below 94.7%, with 91.8% determined to Paenibacillus polymyxa IAM 13419T. The AAI and POCP values between V-9T and type species of the genera of Paenibacillaceae with available genomes, including Paenibacillus polymyxa, were below the thresholds for defining novel genera. The cell wall of new strain contained a lysine-based peptidoglycan and two teichoic acids, unsubstituted 1,3-poly(glycerol phosphate) and 1,3-poly(glycerol phosphate) substituted at the C(2) of glycerol by glucose. Acid hydrolysates of the cell wall included glucose, galactose and glycerol. Strain V-9T contained menaquinone MK-7 as the sole isoprenoid quinone, anteiso-C15:0, anteiso-C17:0, iso- C15:0 and iso-C16:0a as the dominant fatty acids, and phosphatidylglycerol, diphosphatidylglycerol, acylphosphatidylglycerol, and phosphatidylinositol as the major polar lipids. The DNA G+C content calculated from the whole genome sequence was 55 mol %. Based on the data obtained, a new genus and species, Gordonibacillus kamchatkensis gen. nov., sp. nov., is proposed with the type strain V-9T (=VKM B-2647T = DSM 26726T). [ABSTRACT FROM AUTHOR]

Abstract—Possible causes of surface subsidence of the pyroclastic flow formed on the slopes of the Shiveluch volcano, Kamchatka, during the eruption on August 29, 2019 are studied. A series of InSAR (Interferometric Synthetic Aperture Radar) images from acquisitions by the European Space Agency Sentinel-1A satellite for a period from May to October in 2020 and 2021 are used to construct maps of the displacement rates of the volcano surface. An area with large subsidence coinciding with the area of pyroclastic flow is revealed on the volcano's southeastern slope. The maximum subsidence rates are found to be 385 mm/year in 2020 and 257 mm/year in 2021. The thickness of the pyroclastic deposits is estimated from radar images for 2020. The dependence of the subsidence rate on flow thickness has a significant scatter with a rather high correlation coefficient (‒0.69). A thermomechanical model has been constructed, which takes into account compaction of the deposited material due to changes in porosity and density over time. According to the model, to explain the dependence of the subsidence rate of the flow surface on the thickness of rocks, it is sufficient to assume that in addition to surface subsidence, flow cooling was accompanied by a small change in porosity occurred, which, depending on the initial flow temperature, made up to 1.5 to 1.7% for the period from 2019 to 2021. The scatter in the relationship "subsidence rate versus flow thickness" is explained for by the erosion of pyroclastic deposits. [ABSTRACT FROM AUTHOR]

Abstract— Long-term (1962‒2020) observations of air temperature and atmospheric pressure at two weather stations in the region of Petropavlovsk-Kamchatsky, Kamchatka Krai, are analyzed to examine the hypotheses about a connection between increased and decreased meteorological parameter values and their contrasting changes with a final stage of preparation of local Kamchatka earthquakes with magnitudes 5.2‒8.3, which occurred at epicentral distances of 22–440 km and caused perceptible shaking with intensity IMSK-64 ≥ 4–5. To identify meteorological anomalies, we used an empirical method comparing daily mean air temperatures and atmospheric pressures with daily averages of their annual seasonal-mean functions and a formalized method estimating the minimum normalized entropy En, the logarithm of the curtosis coefficient logκ, and the autoregressive measure of nonstationarity Q2 of the time series of air temperature and atmospheric pressure in a moving time window with a length of 112 days shifted by one day. Various types of meteoanomalies before earthquakes were studied on time intervals of seven and 30 days. The correlation between the detected anomalies and subsequent earthquakes was evaluated from the ratio of reliability and validity of the conditional meteorological precursor. It is found that the manifestation of various types of meteorological anomalies before earthquakes is mainly of a random nature. The lack of a pronounced correlation between air temperature increases and subsequent earthquakes casts doubt on the reality of the mechanism of generation of thermal surface anomalies before earthquakes in the lithosphere‒atmosphere‒ionosphere‒magnetosphere coupling (LAIMC) model for the study region. The methods used for meteorological data analysis can be applied in seismic forecasting in the region of the Petropavlovsk-Yelizovo agglomeration, Kamchatka Krai, for diagnosing weather-dependent anomalies in the changes of the ground-based observation data. [ABSTRACT FROM AUTHOR]

The Great Knot is a species from the Scolopacidae family of waders migrating within the East Asian-Australasian Flyway, and studies on this species have contributed greatly to understanding of migration ecophysiology and migration strategies in long-distance migrants. In this paper, we provide the first description of biometric variability and sexual size dimorphism in Great Knots. During the study on the Kamchatka Peninsula, 683 adults and 229 juveniles were measured and sexed molecularly. In adults, the mean measurements of females were larger than in males, except for tarsus length. In juveniles, at the early stage of migration from breeding to wintering grounds, apparently growth was not complete. Sexual dimorphism was small, with only wing length being significantly longer in females than in males. All dimensions of juveniles were smaller than those of adults, especially in bill length. The most sexually dimorphic trait in both adults and juveniles was wing length, and the most effective discriminant function with wing length as a single predictor correctly identified the sex of 76% of birds in both age classes. However, molecular sexing is the method of choice for reliable sexing, especially in juveniles. [ABSTRACT FROM AUTHOR]

The origin of volcanism along the Kuril–Kamchatka Island Arc (KKIA) was analyzed. Geophysical observations show variations in the slab parameters. Different widths of the volcanic belt in the northern and southern parts of the KKIA are caused by changes in the slab dip angle. The rift system of the Bussol Strait may be generated by significant changes in the slab velocity in the central segment of the KKIA. We proposed that the back-arc basin plays a predominant role in the formation of various parameters of the slab and manifestations of volcanism along the KKIA. [ABSTRACT FROM AUTHOR]

The aim of this work was to analyse the effect of blackcurrant (Ribes nigrum) and kamchatka honeysuckle (Lonicera caerulea var. Kamtschatica) extracts on the physico-chemical properties, microbiological and sensory quality of fermented meat product. Analyses were performed after 5, 15, 30 and 45 days of ageing. The addition of blackcurrant and kamchatka honeysuckle extracts in quantities of 3 and 5 ml.kg-¹ did not adversely affect the ageing process of fermented meat product samples determined based on pH. After 45 days of ageing period, we found higher malondialdehyde (MDA) values in all experimental groups (except for the experimental group with the addition of 3 ml blackcurrant extract). The addition of the extracts in the tested quantities did not cause demonstrable differences in the intensity values of brightness (L*), red (a*) and yellow (b*) colour throughout the ageing period. Microbial examination indicates that the addition of blackcurrant and kamchatka honeysuckle extracts did not inhibit the growth of starter culture. Bacteria of the genus Lactobacillus and Staphylococcus predominated in all experimental groups. Family Enterobacteriaceae was not detected after 45 days of ageing and storage. Moulds were detected only after 5 days of ageing and in the experimental groups with the addition of blackcurrant extracts. The counts of yeasts gradually increased with increasing ageing time in all experimental groups. Sensory analysis revealed a beneficial effect of kamchatka honeysuckle extract in the amount of 3 ml.kg-1 after 30 days of fermented sausages ageing. On the other hand, blackcurrant extract in higher amount (5 ml.kg-1) had a beneficial effect on sensory quality after 30th day. Traditional kamchatka honeysuckle aroma was probably transferred into the samples of meat product and caused lower sensory scores. Due to the known functional properties of black currant and kamchatka honeysuckle, we recommend carrying out their further analyses on the quality of fermented meat products. [ABSTRACT FROM AUTHOR]

We have carried out a correlation analysis to study relationships between the trace element (TE) composition of mud-volcanic and carbon dioxide fluids in the Greater Caucasus on the one hand and the chemical composition of upper, middle, and lower crust, as well as various kinds of biota on the other hand. It has turned out to be possible to relate the roots of the associated fluid flows with definite stages of the Earth's crust, as well as to point out, in several cases, the kind of the dominant original organic matter. The roots of both carbon dioxide fluids and mud-volcanic fluids were shown to reside in the middle crust. We have compared correlative relationships for deep-seated fluids in the Caucasus with those for oils in several major oil-gas basins in Russia and in the fluid systems of Kamchatka. [ABSTRACT FROM AUTHOR]

Simulation of a potential collapse on Koryaksky Volcano showed the most likely direction of movement for a debris avalanche. The periodic fumarolic activation of the volcano provides evidence of the circulation of meteoric waters and of favorable conditions for replacement of the bedrock in the volcanic edifice resulting in landslide deposits. Satellite data were used to study surface ground deformation. The northeastern slopes of Koryaksky are rising relative to the subsiding southwestern slopes. Recalling that Koryaksky volcano stands at a distance of 10 km from Avachinsky Volcano which has produced massive explosive debris deposits during its history, the present study is of utmost urgency. The Elizovo–Petropavlovsk agglomeration (which includes the town of Elizovo and Petropavlovsk-Kamchatsky, as well as adjacent population centers in Elizovo District), which is in immediate vicinity of Koryaksky Volcano, harbors more than a half of all population of Kamchatka, as well as facilities that produce over half of all income in the region. Consequently, the assessment of naturally occurring processes on the volcano with a view to further development of a plan to minimize their negative impact is critically important for the economy of Kamchatka. [ABSTRACT FROM AUTHOR]

The estimation of the degree of tectonic fragmentation for upper lithosphere following the method of Yu.V. Nechaev (2010) is based on calculations of specific lineament lengths. We used data for three regions—Northwest Caucasus, the Voronezh Anteclise, and the Malko–Petropavlovsk zone in Kamchatka—to test whether other morphometric parameters could be used: specific lengths of "weak" zones, elongation lines and water streams, as well as relief curvature. Their anomalies are confined to seismic areas and to areas of hydrothermal and magmatic activity. We show that the most information is provided by 3D models of tectonic fragmentation that incorporate specific lengths of "weak" zones and water stream lengths. [ABSTRACT FROM AUTHOR]

We analyzed published datasets relating to the composition of glasses from melt inclusions in minerals of volcanics from the Eastern Volcanic Belt and Sredinny Range of Kamchatka. A significant difference was found between the distribution of silica concentration in the rocks and melts: intermediate and basic compositions are most common among the rocks, whereas the glasses in melt inclusions are predominantly acidic. The distribution of major and trace elements was analyzed. It was shown that the contents of some elements are environment-specific (e.g., Nb and light REEs). We identified trace element ratios in melts that most strongly correlate with the geodynamic setting. [ABSTRACT FROM AUTHOR]

Sulfur-containing ejecta of Plinian-type eruptions can be transported to great distances in gas pores of ash particles. The mean concentration of sulfur in the rhyolite tephra of the ca. 1500 BP Opala eruption is 310 ppm. The maximum concentration can reach 800 ppm. We have found a relationship between sulfur concentration in bulk samples and grain-size composition: sulfur is mostly found in the 0.25‒0.50 mm fraction consisting of elongate ash particles with elongate gas pores 1.0‒10.0 µm long. The most likely cause why sulfur concentration depends on the structure of ash particles consists in the fact that sulfur compounds of the water-soluble complex are preserved inside gas pores; sulfur-containing compounds that have been sorbed on the surface of ash particles were removed by precipitation during the time the tephra resided in continental settings. When ash particles that contain sulfur compounds on the inner surface of gas pores come into bottom sediments during Plinian-type eruptions like that on Opala Volcano ca. 1500 BP, that can affect the geochemistry of lithogeny and rearrange the mineral phases that are sensitive to the presence of oxide-sensitive agents in the sedimentary sequence during diagenesis. [ABSTRACT FROM AUTHOR]

This work is concerned with classification and study of the composition and properties of hydrothermal zeolites from the Yagodninskoe deposit, (Kamchatka) which were formed in volcanic rocks. The study involved X-ray phase analysis and X-ray fluorescence, optical and scanning electron microscopy. We determined specific syrface AREA the pore size distribution, as well as cation exchange capacity in zeolites. The study resulted in the identification of four main rock types at the deposit: the original unaltered perlites, zeolites rock, zeolitized tuffs, as well as poorly zeolitized tuff breccias. The Content of zeolite group minerals reaches 70%. The minerals mostly include clinoptilolite and, to a lesser degree, mordenite, stilbite, and heulandite. The zeolites are of the alkaline type, with the cation exchange capacity equal to 205.9 mg-equi/100 g. It has been found that these zeolites were mostly formed from perlites and tuff breccias. It is pointed out that the Yagodninskoe zeolites are high quality minerals, and make a promising object of further exploration. [ABSTRACT FROM AUTHOR]

Heterogeneous grains in the heavy fractions of the placers of the Olkhovaya-1 river (Kamchatka Cape Peninsula, Eastern Kamchatka, Russia) containing Au-Ag, Au-Cu, and Au-Ag-Cu particles were analyzed using scanning electron microscopy, electron-probe microanalysis, and X-ray powder diffractometry. The analyses showed that auricupride dominates in some grains, whereas in others, the main phases are tetra-auricupride or Ag-rich and (or) Au-rich alloys. It was revealed that in the central parts of some grains of exsolution structures, auricupride Cu3.04–2.74Au0.96–1.26 (Ag < 1 wt.%) occurs in intergrowths with low-fineness Ag0.86–0.67Au0.09–0.33Cu<0.05 solid solutions (160‰–480‰), and tetra-auricupride Cu1.12–0.87Au0.88–1.11Ag<0.02 (Ag < 2 wt.%) occurs with higher-fineness Au0.73–0.62Ag0.2–0.38Cu<0.07 solid solutions (520‰–850‰). We also observed, mainly in the peripheral parts of the grains, insignificant amounts of secondary phases that were compositionally similar to Cu2Au, Cu3Au2, Au3Cu2, Au2Cu, Au3Cu, high-fineness gold with impurities of Cu and occasionally Ag (>850‰), and pure gold. In intergrowths with auricupride and tetra-auricupride, we also observed earlier-formed silicates (garnet, pyroxene, chlorite, epidote, titanite), syngenetic sulfides (pyrrhotite, bornite, galena), and later minerals (chalcocite, covellite, anilite, cuprite, goethite, etc.). The XRD analysis of the peripheral parts of some grains showed the presence of auricupride (Cu3Au), tetra-auricupride CuAu (I) and Cu(Au0.92Ag0.08) (II), and gold. The profiles show the absence of peaks of the Au3Cu phase and other Au-Ag-Cu phases identified by the EMPA, which is likely due to their low concentrations in the samples or their structural similarity to gold. It is assumed that the probable source of Au-Ag-Cu mineralization in the Olkhovaya-1 river placers is located in the upper reaches of watercourses that erode the ultrabasic massif of Mounts Soldatskaya and Golaya (Kamchatka Cape Peninsula). [ABSTRACT FROM AUTHOR]

Featured Application: Method of producing bioferment from fruit waste for use in the food industry, cosmetics industry and dietary supplements, by fermentation with environmental strains. Kamchatka berries (Lonicera caerulea L.) are known for their high content of phenolic compounds or vitamins, which is reflected in their antibacterial, detoxifying and anti-inflammatory properties. They are used in the production of jams, juices, wines and as natural dye. A bioferment was prepared from the pomace of the Kamchatka berry varieties Aurora and Indigo Gem and the strains Saccharomyces cerevisiae and Lacticaseibacillus paracasei, which was used to prepare a cosmetic preparation with a concentration of 5% in accordance with the guidelines of the COSMOS certification body. We conducted physico-chemical and organoleptic analyses and bioactive profile characterisation (UHPLC-DAD and UHPLC-ESI-MS/MS). The results showed that the presence of caffeic acid (4.47 ± 0.07 mg/100 g) was detected after fermentation of Kamchatka berry pomace. In addition, vitamin C content increased by 141% after fermentation. The results of stability tests showed that in the process of physico-chemical analysis of the cosmetic preparation with bioferment of Kamchatka berry pomace, the pH should oscillate in the range of 4.38–4.76 ± 0.01. Stability tests showed that the cosmetic should be protected from high temperatures and UV radiation and proved that the product is stable under changing conditions, resulting in lower transport and storage costs. [ABSTRACT FROM AUTHOR]

Important problems of magma differentiation, formation of native metals, and ore-forming processes in the Earth's crust are often related to participation of hydrogen. In this paper, new experimental data on the crystallization of andesite melts at high temperatures (900–1250°C) and hydrogen pressures (10–100 MPa) have been obtained, which clarify the possible role of hydrogen in the processes occurring in andesite melts in the Earth's crust and during volcanism under strongly reduced conditions ( = 10–17–10–18). In the crystallization experiments, it was found out that the compositions of the crystals (pyroxenes and plagioclases) formed in experiments on crystallization of andesite melt under hydrogen pressure closely correspond to the crystal compositions of lava flows of Avacha volcano in Kamchatka. This result can be considered as an experimental confirmation of the participation of hydrogen in the volcanic process. [ABSTRACT FROM AUTHOR]

Abstract—As part of the international collaboration of several research groups from Russia, France, and Germany, 77 temporary seismic stations were installed in the summer of 2015 for one-year period to conduct a detailed study of the deep structure of the Earth's crust and upper mantle in the region of the Klyuchevskoi Volcano Group (KVG), Kamchatka Peninsula. One of the results of the KISS experiment (Klyuchevskoi Investigation –Seismic Structure of an extraordinary volcanic system) was the final catalog based on the joint data from the temporary stations and the permanent network of the Kamchatka Branch of the Geophysical Survey of the Russian Academy of Sciences (KB GS RAS). The catalog comprises 2136 events, including 560 for which the permanent network catalog lacked sufficient data for correct processing. The catalog in.xlsx format and the station bulletin in.isf format are presented in the supplementary material to the paper. A comparative analysis is performed of joint solutions of two catalogs, one obtained solely from the data of the KB GS RAS permanent network stations and another from a denser seismic network integrated with KISS stations. [ABSTRACT FROM AUTHOR]

This study presents the findings of a splitting analysis conducted on core-refracted teleseismic shear waves (SKS, SKKS and PKS , called together as XKS) and local shear waves, obtained from a dense seismological network spanning the Kamchatka Peninsula. The objective of the study is to examine the pattern of mantle flow beneath the study area through the investigation of seismic anisotropy. The peninsula is situated at the northeastern end of the Kuril–Kamchatka subduction zone, where the Kuril trench intersects with the western boundary of the Aleutian trench. The data set utilized in this study comprises waveform data from a dense network of seismic stations (99 broad-band and short-period stations for the local shear wave splitting analysis and 69 broad-band stations for the SKS splitting analysis). The seismograms were downloaded from publicly available data repositories including the IRIS Data Management Center and the GFZ Data Services (GEOFON program). The dense station coverage allows us to investigate the lateral variations in anisotropy, providing insights into the flow patterns within the mantle. The processing of the combined data sets of local shear wave and teleseismic XKS waves allowed us to partially decipher the source of anisotropy in the mantle. Small delay (splitting) times (∼0.35 s) observed from the local- S data suggest that anisotropy in the mantle wedge is relatively weak with lateral variations. Larger splitting times (∼1.1 s) observed for the XKS waves relative to local S suggest that the main part of splitting on the XKS waves occurs in the subslab mantle. On the other hand, the rotational pattern of seismic anisotropy observed by both the local S and XKS waves suggests the presence of a toroidal flow at the NE edge of the subducting slab, which affects both the mantle wedge and subslab mantle. For the regions away from the edge of the slab, the mantle flow seems to be governed mainly by the drag of the lithospheric plate over the underlying asthenosphere. [ABSTRACT FROM AUTHOR]

This paper reports results from a study of two new genetic types of diamond discovered in Kamchatka. These diamonds were formed under extra-mantle conditions, as can be inferred from the fact that there is no indication of post-crystallization annealing with the formation of aggregated nitrogen defects in them. The first of these types is defined by us as volcanic-atmoelectrogenic. This is formed directly in a volcanic ash-gas cloud due to deep-seated methane released by atmospheric electric discharges. The second genetic type of diamonds is formed at depth within a magmatic-pneumatolytic-hydrothermal ore deposit, and can be defined as the explosive-tuffisite type. The industrial potential of these types enables us to assert the discovery of a new diamondiferous province, i.e., the Kamchatka Province. [ABSTRACT FROM AUTHOR]

The Evevpenta ore occurrence is situated in the northeastern part of the Central Kamchatka volcanic belt (Kamchatka Peninsula, Russia), and lies among andesitic volcanic complexes of the Neogene age. The ore bodies are veins, zones of quartz streaks, and hydrothermal breccias, accompanied by aureoles of argillization which transition into propylites at the periphery. The formation of noble-metal mineralization occurred through two phases: the hypogene (hydrothermal) phase and the hypergene phase. For the hypogene phase we have identified two mineral associations related to noble-metal mineralization: the Central area contains gold—telluride–quartz mineralization, while the Northern area hosts telluride–sulfide–quartz mineralization. The hypergene mineral association with native gold occurs within the Central area only. Based on data relating to the material composition of the ores we show that the Evevpenta ore occurrence is a typical member of epithermal reduction-alkaline or low sulfidation deposits. [ABSTRACT FROM AUTHOR]

This paper examines the Karymsky Volcanic Center to estimate how much volcanic and hydrothermal activity affects the chemical composition of river water. We evaluate the volumes of major and trace elements coming to the Pacific Ocean via the Karymsky River. We assess the quality of river water in compliance with the regulations for potable water, water used for household work, and in fisheries. It is shown that the formation of ion load of the river water mostly occurs by inflow of thermal waters, as well as due to water-soluble complexes of ashes discharged by Karymsky Volcano and coming to the catchment area of the river. The annual volume of dissolved material transported by the river to the Kronotsky Bay of the Pacific Ocean amounts to more than 90 kilotons. [ABSTRACT FROM AUTHOR]

This paper provides information on the volumes of ejecta discharged by lateral and summit eruptions during the period from 1932 to 1989. We show that the volumes of ejecta from lateral eruptions were larger than those of the summit eruptions for the period. We examine subsequent variations in the character of eruptions. Lateral and summit eruptions had been occurring on the volcano from 1932 to 1989, and summit eruptions alone from 1990 to 2016. Changes occurred in 2016 with the resumption of lateral eruptions on the volcano's slopes. We note one characteristic feature, namely, all summit eruptions terminated in collapse events in the central crater. The collapse structures are characterized. The formation of the collapse structures is related to changes in the density and volume of magma as it was ascending to the ground surface. Data are provided relating to the summit eruptions of 2019–2021 and on the 2021 lateral eruption named after G.S. Gorshkov. New data are presented showing changes in the morphology of the summit crater during eruptions and collapses in the crater after the eruptions. [ABSTRACT FROM AUTHOR]

Volcanic lakes in the Kuril-Kamchatka region are difficult to access, and for this reason, they remain poorly studied, with only scattered and brief data available. The authors have conducted a study of 10 lake basins using modern digital echolocation survey techniques and have also compiled and summarized published data for 15 lakes in the region, calculating their main morphometric characteristics. It has been established that many caldera lake basins are modified by young explosive funnels, extrusive or effusive domes, and exhibit traces of hydrothermal activity. While lakes of the same genetic type in the Kuril-Kamchatka region are similar in depth and depression forms, the group of caldera lakes shows less homogeneity across all morphometric indicators. It was found that the absolute heights of the reservoirs on Kamchatka Peninsula are generally greater than those on the Kuril Islands, as is often the case with the size of their basins. The volcanic lakes under study can rapidly change their volume and shape under the influence of endogenous processes. For the first time for this region, on the base of repeated observations, underwater extrusive dome rate growth and the approximate rates of 2 lake level changes were calculated. Repeated observations of lakes in the Ksudach calderas (Kamchatka) and on Simushir Island indicate approximate rates of level changes: a decrease ranging within 0.5–0.6 m per year (over a 27-year observation interval) and an increase reaching up to 0.26 m per year (over a 48-year interval). The growth rate of the underwater extrusive dome in Lake Shtyubel has averaged 1–1.6 m per year over the past 25 years. This analysis has facilitated the first generalization regarding the morphology and developmental features of crater and caldera lakes in the Kuril-Kamchatka region of Russia, representing an important step in their study. The results obtained will provide a solid foundation for subsequent research in this region and may be of interest to researchers studying other volcanic lakes. [ABSTRACT FROM AUTHOR]

In this study, we used the Pn tomography method to obtain detailed velocity and anisotropy structures of the uppermost mantle beneath Sakhalin–Kuril–Kamchatka region for improving the understanding of plate subduction, arc–arc collision, and volcanism. We found low Pn velocities beneath volcanoes and areas characterized by pronounced tectonic activity and high Pn velocities with strong anisotropy in the subducting plate. Low Pn velocity anomalies beneath southern Sakhalin connected the low‐velocity anomalies in the mantle and crust, indicating the ascent of fluid or melt, and may provide a magmatic source for the rear‐arc Rishiri volcano. In the absence of plate subduction, low‐velocity anomalies and north–south Pn anisotropy manifested beneath northern Kamchatka, revealing the lateral propagation of mantle flow beneath this northern region. We suggest that the eastern boundary of the slab window at the Kamchatka–Aleutian junction is likely to be located near the Komandorsky Islands. Plain Language Summary: The Northwest Pacific region is prone to recurrent earthquakes and volcanic activities, attributable to plate subduction and multiple plate interactions. This study, focuses on elucidating the uppermost mantle structure beneath the Sakhalin–Kuril–Kamchatka region using seismic tomography. Beneath the island chain featuring volcanoes and areas with a lot of tectonic activity, seismic waves travel slower. This phenomenon implies the possible presence of magma or hot materials beneath these regions. In southern Sakhalin, a linkage is established through low Pn velocities connecting areas of low seismic wave velocity in the deeper mantle and crust. This linkage suggests a conduit for fluids or molten materials, potentially feeding for the Rishiri volcano situated beyond the volcanic arc. Strong low velocities, coupled with north–south Pn fast directions are identified beneath northern Kamchatka, indicating the northward propagation of mantle flow. Our imaging analysis suggests that the eastern edge of the slab window (the region where the plate is absent) at the Kamchatka–Aleutian junction is likely proximate to the Komandorsky Islands. This study provides new seismological insights into the plate collision and subduction processes as well as the deep structures in the Sakhalin–Kuril–Kamchatka region. Key Points: Low Pn velocities clarify the upward path of the mantle‐derived thermal material beneath Sakhalin and its influence on surface volcanismStrong low Pn velocities and N–S anisotropy beneath northern Kamchatka signify the lateral propagation of mantle flow directed northwardThe eastern boundary of the slab window at the Kamchatka–Aleutian junction may be located near the Komandorsky Islands [ABSTRACT FROM AUTHOR]

Volcanoes produce a variety of seismic signals and, therefore, continuous seismograms provide crucial information for monitoring the state of a volcano. According to their source mechanism and signal properties, seismo‐volcanic signals can be categorized into distinct classes, which works particularly well for short transients. Applying classification approaches to long‐duration continuous signals containing volcanic tremors, characterized by varying signal characteristics, proves challenging due to the complex nature of these signals. That makes it difficult to attribute them to a single volcanic process and questions the feasibility of classification. In the present study, we consider the whole seismic time series as valuable information about the plumbing system (the combination of plumbing structure and activity distribution). The considered data are year‐long seismograms recorded at individual stations near the Klyuchevskoy Volcanic Group (Kamchatka, Russia). With a scattering network and a Uniform Manifold Approximation and Projection (UMAP), we transform the continuous data into a two‐dimensional representation (a seismogram atlas), which helps us to identify sudden and continuous changes in the signal properties. We observe an ever‐changing seismic wavefield that we relate to a continuously evolving plumbing system. Through additional data, we can relate signal variations to various state changes of the volcano including transitions from deep to shallow activity, deep reactivation, weak signals during quiet times, and eruptive activity. The atlases serve as a visual tool for analyzing extensive seismic time series, allowing us to associate specific atlas areas, indicative of similar signal characteristics, with distinct volcanic activities and variations in the volcanic plumbing system. Plain Language Summary: Volcanoes generate diverse seismic signals, and analyzing continuous seismograms can offer valuable insights into a volcano's behavior. However, classifying and cataloging these signals is challenging, particularly for long‐period signals such as volcanic tremors with varying signal characteristics. In this study, we utilize seismic time series data from the Klyuchevskoy Volcanic Group in Russia, employing machine learning and signal processing methods to transform and represent the time series data. The resulting "seismogram atlas" helps identify changes in signal properties, revealing a dynamic seismic wavefield linked to the evolving plumbing system of the volcano. This approach provides a comprehensive understanding of the volcanic behavior in time by connecting signal variations to different volcanic states, such as shifts in activity depth, reactivation, and eruptive periods. These findings highlight the unique characteristics of continuous seismograms near the volcano, suggesting that there is valuable information in the complete seismic time series that conventional methods and event catalogs may miss. Key Points: With machine learning, we analyze 1 year long seismic time series at individual stations at Klyuchevskoy volcanoContinuous evolution of the signal characteristics over time reflects dynamic changes occurring in the volcano plumbing systemDifferent episodes of volcanic activity are well distinguished on UMAP‐based seismogram atlases [ABSTRACT FROM AUTHOR]

The Northeast Asian endemic species of lichen-forming fungus Umbilicaria krascheninnikovii is herein discussed in the global context of biogeography and phylogeny of the U. aprina group. The name U. krascheninnikovii has been erroneously used by lichenologists for Umbilicaria spp. from high latitudes or altitudes worldwide, as there are omphalodisc apothecia and rough "crystals" of a necral layer on the upper surface. To test the monophyly and phylogenetic relationships within the U. aprina group, four independent DNA regions (nrITS/5.8S, RPB2, mtLSU, and mtSSU) were used for six rare species, including a dozen specimens of U. krascheninnikovii from its locus classicus in Kamchatka. The study is based on the phylograms obtained using maximum likelihood and a Bayesian phylogenetic inference framework. As a result of phylogenetic and biogeographic analyses, it was shown that U. krascheninnikovii is a neo-endemic of the areas of modern volcanism in Kamchatka, Japan, as well as in the Kurile Islands, where this species was recorded for the first time. The morphology of U. krascheninnikovii is herein described and illustrated. Increasing the role of the sexual process and reducing asexual thalloconidiogenesis are shown to be apomorphic traits in the U. aprina group. The combination of sexual and asexual reproduction provides adaptive advantages in changing environmental conditions. [ABSTRACT FROM AUTHOR]

The reduction in the area and volume of glaciation in all mountain regions of the Earth has strongly accelerated for the last decades. In this work, we analysed the trends of the main climatic parameters which caused the glacier recession in the Kamchatka Peninsula. It was shown that the glaciers of the northern part of the Sredinny Range decreased by 125 km2 (35.6%) from 1950 to 2016–2017. The average rate of their reduction in the period from 2002 to 2016–2017 (1.45%/year) increased approximately 4.3 times compared to the period 1950–2002 (0.34%/year). The greatest reduction is observed in small glaciers with an area of less than 0.1 km2 and in glaciers with southeastern and southern expositions. On the Kronotsky Peninsula, the glacier area reduction for 1957–2019 was equal to 32.1 km2 (35.6%), and the rates were almost the same in the periods of 1957–2000 (0.61%/year) and 2000–2019 (0.67%/year). According to the data of weather stations and ERA5 reanalysis, it was shown that, in the ablation (summer) period the warming rate was minimal (0.3°C/10 years) and in the accumulation period a significant decrease in precipitation (5%–10%/10 years) was revealed in some areas. At the same time, a significant increase in the radiation balance was revealed in the warm season along with a tendency in downward shortwave radiation increase for the last two decades due to a decrease in cloud amount. These trends are in good agreement with the growth of the geopotential height over the North Pacific during the warm season in the 21st century, and with the growth of velocity divergence in the middle troposphere and the intensification of downward air movements. All this confirms an increase in anticyclone frequency in the warm season, which could be the cause of a radiation balance increase and, consequently, an increase in glacier ablation. [ABSTRACT FROM AUTHOR]

The authors explore the trends in the human health risks caused by air pollution and changing levels of weather and climate comfort on the territory of Russia in 2020–2050 under two climate change scenarios. Generally, the dynamics of risks is expected to be moderate. It will presumably be characterized by inter-scenario variability and dispersion by the country's climate zones. In certain areas, primarily in Siberia, very noticeable trends have been revealed. The paper shows a need for additional attention when planning the measures of adaptation to climate change in southern and central regions of European Russia, most of Western Siberia, the Magadan oblast and Kamchatka. [ABSTRACT FROM AUTHOR]

Atacamite, empirical formula (Cu1.97Zn0.01)Cl0.94(OH)3.02, from the paleofumaroles of the monogenic volcano of Mount 1004, Tolbachik, Kamchatka, Russia, has been studied by thermal and electron microprobe analyses, X-ray powder diffraction, IR and Raman spectroscopy, and Calvet microcalorimetry. The thermal decomposition of atacamite was studied using X-ray diffraction and IR spectroscopy. The enthalpy of formation from elements for atacamite of the theoretical composition Cu2Cl(OH)3 (−810.2 ± 7.7 kJ/mol) was determined by melt dissolution calorimetry, and the Gibbs energy of formation (−657.0 ± 7.7 kJ/mol) was calculated. The stability of atacamite in the Cu–O–Cl–H system was thermodynamically modeled based on the obtained data, and the boundaries of its stability field were calculated under conditions of high alkalinity and high acidity of the mineral-forming medium. [ABSTRACT FROM AUTHOR]

A new mineral cuprodobrovolskyite, ideally Na4Cu(SO4)3, was found in sublimates of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with petrovite, saranchinaite, euchlorine, krasheninnikovite, langbeinite, calciolangbeinite, anhydrite, sanidine, tenorite and hematite. Cuprodobrovolskyite occurs as coarse hexagonal tabular or equant, typically skeletal crystals up to 1 mm and their clusters or crusts up to 1.5 cm × 2.5 cm in area. The mineral is transparent, light blue or greenish-bluish to almost colourless with vitreous lustre. Cuprodobrovolskyite is optically uniaxial (+) with ω = 1.509(3) and ε = 1.528(3). The empirical formula calculated on the basis of 12 O apfu is (Na3.64K0.09Pb0.03)Σ3.76(Cu0.51Ca0.22Mg0.16Zn0.07Al0.01Mn0.01)Σ0.98S3.04O12. The unit-cell parameters of cuprodobrovolskyite calculated from the powder X-ray diffraction data are: a = 15.702(2), c = 22.017(5) Å, V = 4701.0(2) Å3, space group R 3 and Z = 18. The crystal structure was studied using the Rietveld method, R p = 0.0246, R wp = 0.0325, R 1 = 0.0521 and wR 2 = 0.0770. Cuprodobrovolskyite is an isostructural analogue of dobrovolskyite Na4Ca(SO4)3 with Cu prevailing over Ca. One of the main features of cuprodobrovolskyite is Cu2+ in 7-fold coordination. On the basis of relationships with saranchinaite Na2Cu(SO4)2 and petrovite Na12Cu2(SO4)8 in the Arsenatnaya fumarole and the results of heating experiments, cuprodobrovolskyite is considered as the highest-temperature phase among anhydrous Na–Cu sulfate minerals. [ABSTRACT FROM AUTHOR]

Okruginite, Cu2SnSe3 is a new mineral discovered from the high-sulfidation epithermal Au Ozernovskoye deposit, Kamchatka peninsula, Russia. It occurs as distinct Se-rich zones in Se-bearing mohite crystals or forms aggregates of small crystals 10–15 μm in size in quartz. In plane-polarised light, okruginite appears brownish grey. Pleochroism and bireflectance are discernible, anisotropy is weak, with rotation tints pale blue-grey to pale grey-brown; it exhibits no internal reflections. Reflectance values of the synthetic analogue of okruginite in air (R 1, R 2 in %) are: 25.9, 26.5 at 470 nm, 27.5, 26.5 at 546 nm, 27.8, 28.4 at 589 nm and 27.7, 28.4 at 650 nm. Twenty seven electron-microprobe analyses of okruginite give an average composition: Cu 29.48, Sn 28.10, Se 33.40 and S 8.75, total 99.73 wt.%, corresponding to the empirical formula Cu1.99Sn1.02(Se1.82S1.17)Σ2.99 based on 6 atoms; the average of seven analyses on its synthetic analogue is: Cu 23.62, Sn 24.37 and Se 49.09, total 97.08 wt.%, corresponding to Cu1.86Sn1.03Se3.11. The density, calculated on the basis of the empirical formula, is 5.126 g/cm3. The mineral is monoclinic, space group Cc , with a = 6.9906(2), b = 12.0712(4) Å, c = 6.9723(2) Å, β = 109.350(10)°, V = 555.1(2) Å3 and Z = 4. The crystal structure was solved and refined from the powder X-ray-diffraction data of synthetic Cu2SnSe3. Okruginite is the selenium-end member of the Cu2SnS3–Cu2SnSe3 solid solution. The mineral name is in honour of Dr. Victor Mikhailovich Okrugin, a Russian mineralogist, for his contributions to mineralogy and geology of epithermal deposits, in particular of the Au–Ag deposits in Kamchatka. [ABSTRACT FROM AUTHOR]

This paper discusses the problems of interpreting the study results obtained for metal and mineral microinclusions by the scanning electron microscopy with energy-dispersive X-ray microanalysis, which are related to the matrix material effect. The method was shown to work well when studying "relatively large" (5–10 μm) microinclusions for the purpose of phase identification and semi-quantitative determination of their composition normalized to 100%. The potential for "cleaning" analysis results from "additives" caused by matrix elements, as well as the criteria for assessing a distance from boundaries of a micro-object at which the matrix effect becomes minimum, are considered. The results we obtained by means of these approaches are illustrated by examples of petrology and metallogeny of igneous rocks studied in the Kamchatka region and the Stanovoy fold belt. This study made it possible to obtain new data on petrological processes in the mantle–crust substrate under the active volcanic arc and on the ore–magmatic system evolution under the ancient active continental margin. [ABSTRACT FROM AUTHOR]

The paleodirection and paleointensity of the geomagnetic field are determined from seven andesibasalt–basalt samples of three lava flows (L1–L3) from the Avachinskii (Avacha) volcano. Based on the sample from the recent lava flow TFE-50 (Tolbachik Fissure Eruption), the reliability of the Thellier–Coe method for geomagnetic field paleointensity determination is demonstrated: the deviation of the calculated Han from the IGRF12 values is at most 3% with a quality factor q > 13. The age of lava flows L1–L3 is refined using paleomagnetic data. Flows L1, L2 of the Molodoi Cone were formed in 1827 and 300–600 years ago, respectively, and the age of flow L3 at the crest of the somma is determined at 30–32 ka, which agrees with the known age estimate of the debris avalanche associated with the catastrophic destruction of the Avachinskii volcano 29 900 ± 37 900 14C years ago. [ABSTRACT FROM AUTHOR]

Mesozoic gabbro from the Stanovoy convergent margin and adakitic dacite lava from the Pliocene–Quaternary Bakening volcano in Kamchatka contain iron–titanium oxide–apatite–sulfide–sulfate (ITOASS) microinclusions along with abundant isolated iron–titanium minerals, sulfides and halides of base and precious metals. Iron–titanium minerals include magnetite, ilmenite and rutile; sulfides include chalcopyrite, pyrite and pyrrhotite; sulfates are represented by barite; and halides are predominantly composed of copper and silver chlorides. Apatite in both gabbro and adakitic dacite frequently contains elevated chlorine concentrations (up to 1.7 wt.%). Mineral thermobarometry suggests that the ITOASS microinclusions and associated Fe-Ti minerals and sulfides crystallized from subduction-related metal-rich melts in mid-crustal magmatic conduits at depths of 10 to 20 km below the surface under almost neutral redox conditions (from the unit below to the unit above the QFM buffer). The ITOASS microinclusions in gabbro and adakite from the Russian Far East provide possible magmatic links to iron oxide–apatite (IOA) and iron oxide–copper–gold (IOCG) deposits and offer valuable insights into the early magmatic (pre-metasomatic) evolution of the IOA and ICOG mineralized systems in paleo-subduction- and collision-related geodynamic environments. [ABSTRACT FROM AUTHOR]

The Pauzhetka geothermal field was surveyed to study the mineral deposits that were formed as thermal water was discharged from well separators. We studied the compositions, structure, and geochemical properties of these sediments along the flow and in vertical cross sections of manmade "sinters". It was found that, at the beginning of thermal water discharges, the sediments were composed of X-ray-amorphous mordenite–opal mixtures; later on, the sediments became wholly siliceous. The zeolite component of the mineral deposits determines their high sorption properties in relation to Au, Ag, Hg, As, Rb, Sr, Ba, Cs and other elements; the mordenite matrix receives sulfides of iron, silver, and copper. It is shown that the mineral deposits which were formed at the ground surface of the Pauzhetka geothermal field constitute an indicator of alkaline mineral-forming and ore-forming environment in the lower horizons of the Pauzhetka geothermal system. [ABSTRACT FROM AUTHOR]

Areas where large shallow earthquakes can occur in the future are identified by considering characteristics of the attenuation field of short period shear waves in the lithosphere. A total of over 360 records of earthquakes at depths of 0–33 km have been processed; these earthquakes were recorded at the PET station from two regions enclosed in the coordinates 45.0°–50.5° N and 54.0°–56.5° N (for the sake of brevity these regions will be referred to in what follows as the southern and the northern region, respectively). In addition, for comparison purposes we used records of earthquakes made at the KGB station from the area between 52° and 54° N. We used a method based on the ratio of peak amplitudes of Sn and Pn waves. It was found that the overall attenuation in the lithosphere of the northern region is much greater than that for the southern. At the same time we note that the attenuation in both of these areas is below that in northeastern Japan. The relatively lower attenuation occurs in the rupture zones of the great earthquakes occurring in 1952 (Mw = 9.0) and in 1963 (Mw = 8.6), that is, at least 60 years ago in the southern region, while the higher attenuation occurs in the rupture zones of recent events, 1997 (Mw = 7.8), 2006 (Mw = 8.3), and 2018 (Mw = 7.3). These data are consistent with the previous inferences, namely, that typical large earthquakes in subduction zones occur in earth volumes with higher concentrations of fluids in the uppermost mantle. Following large and great earthquakes, deep fluids are rising during a few decades, producing a decrease in the attenuation of the uppermost mantle. We have identified zones of high attenuation where large (Mw ≥ 7.7) earthquakes occurred long ago. We hypothesize that active precursory processes are occurring in these zones (primarily in the Avacha Bay and east of it) before large earthquakes. [ABSTRACT FROM AUTHOR]

This paper provides data on the April 11, 2023 eruption of Sheveluch Volcano. The impact of the eruption has been assessed. The directed explosion destroyed the lava dome which took over 42 years to grow. According to the data acquired just before the eruption, the lava dome had a volume of about 0.53 km3. The eruption produced a field of explosive ejecta ∼70 km2 in area and 0.49 km3 in volume. The directed explosion was accompanied by pyroclastic flows which traveled for distances of 25–30 km from the volcano. The associated ashfall had a length of over 200 km. The weight of an ash sample varied between 1.2 and 43.9 kg/2, depending on the distance to the volcano. The area of ash deposits (with the weight of ash samples over 50 g/m2) was about 17 thousand m2, the volume of the ash deposits was 0.09 km3. Considered in relation to the total volume of ejecta (over 0.60 km3), the April 11, 2023 eruption of Sheveluch should be termed a great catastrophic eruption of this century. [ABSTRACT FROM AUTHOR]

The effect of Kamchatka crab hepatopancreas containing three collagenolytic isoenzymes Collagenase KK and proteinases of Streptomyces lavendulae on metabolic activity and cell death were carried out on in vitro models. It was shown that changes in the protein structure under the influence of Collagenase KK occurred earlier than under the effect of bacterial proteinases. At the same time, activity of Collagenase KK was significantly higher than that of bacterial proteinases (p<0.01). Both preparations had a pronounced time- and dose-dependent effects on metabolic activity of cells. Collagenase KK had low cytotoxic effect, and cells mainly died by apoptosis. Thus, hepatopancreas collagenase has a high activity and proapoptotic effect on cells and can be used in low concentrations for enzymatic disaggregation of tissues. [ABSTRACT FROM AUTHOR]

This paper continues a series of publications on the modification of the Map of Expected Earthquakes (MEE), a method of medium-term earthquake forecasting. It is devoted to the calculation and analysis of retrospective statistical characteristics of dynamic and quasi-stationary prognostic indicators in the Kamchatka region used at this stage in the modernized MEE method. In our calculations we used the regional catalog of earthquakes in Kamchatka over the period from 1962 to 2020. The object of the forecast were earthquakes with Kforecast ≥ 13.5. The slope of the recurrence frequency graph γ with an efficiency value of Jt = 10.7 and JS = 11.3 appeared as one of the most effective precursors for the Kamchatka region, both in time and area. The next most effective (in terms of time) precursor was the number of earthquakes Neq in quiescence form with Jt = 5.8. In terms of area, the most effective precursor is the released seismic energy E2/3, also in quiescence form with JS = 14.7. The value of unconditional probability P(D1) of the occurrence of a strong earthquake was calculated based on a set of dynamic indicators, which turned out to be equal to 0.09. A map of the stationary conditional probability of a strong earthquake has been constructed that takes into account the stationary prognostic indicator "presence of faults in a cell" with values of 0.01 (in the cells where there are no faults) and 0.13 (in the cells where there are). As part of the next stage of work, it is planned to continue expanding the functionality of the algorithm for the medium-term forecast of the MEE. The ultimate goal of modernization is the development of a digital problem-oriented system for medium-term earthquake forecasting using a set of prognostic indicators. [ABSTRACT FROM AUTHOR]

Two decapodid stages of the shrimp Argis lar (family Crangonidae) from the plankton off Kronotsky Gulf, northwestern Pacific, eastern Kamchatka, are described. The available larvae were morphologically compared with decapodids of other species of this family with a shortened development. The first and second decapodid stages are similar in size and structural features of the pleon, carapace, antennae, mandibles, maxillae, pereiopods, and pleopods. The morphology of the telson, maxillipeds, and antennules in the first and second decapodid stages of A. lar differ significantly. At the second decapodid stage, the posterior median spine shifted towards the middle of the carapace. The number of antennular and maxilliped endopod segments increased. The epipod appeared in the third maxilliped. The shape of the telson changed. The terminal spines in the telson disappeared, and the relative length of the angular setae decreased. Kuro shrimp are suggested to have three to five larval stages. [ABSTRACT FROM AUTHOR]

A collection of twenty-eight strains isolated from root nodules of Astragalus inopinatus Boriss. and Astragalus umbellatus Bunge originating from the Kamchatka Peninsula (Russian Federation) was obtained for the first time. Analysis of the 16S ribosomal RNA gene sequence revealed a significant diversity of isolates belonging to 4 genera of the order Hyphomicrobiales: Mesorhizobium, Rhizobium, Bosea and Tardiphaga. The presence of phenotypically and taxonomically different strains (Bosea + Tardiphaga, Bosea + Mesorhizobium, Tardiphaga + Mesorhizobium, Bosea + Rhizobium) in some nodules of both plants was also observed. The symbiotic efficiency of strains isolated from A. inopinatus plants in the nodulation assay showed that most isolates of the genus Mesorhizobium and Rhizobium can form a nitrogen-fixing symbiosis with A. inopinatus, leading to a significant increase in plant biomass compared to the non-inoculated control. [ABSTRACT FROM AUTHOR]

The ecological patterns of the formation of the fauna and bird population of the Urup Island were analyzed for the first time. The method of route accounting on the transects of unlimited width was used. The commonality of the species composition (n = 105) of the avifauna of Urup Island is high: the similarity of local avifauna of the northeastern and southwestern parts of the island is 77%. In general, 34% of species are ubiquitously distributed; 39%, locally; 27%, pointwise. 71 species nest (68%). The taxonomic structure of the avifauna (formed by species from 13 orders) corresponds to zonal and landscape peculiarities of the island territories located on the eastern periphery of Northern Eurasia. Passeriformes (34%), Charadriiformes (33%), and Anseriformes (11%) (typical for the boreal and hypoarctic belts of the Palearctic) predominate. The zoogeographic originality of the local avifauna is caused by a combination of the elements of the Far Eastern islands, Pacific, Siberian, and Chinese faunistic complexes, Siberian–American and widespread species, and Japanese island endemics. The avifauna of Urup Island, which is formed in a system of common zonal–landscape and altitudinal–belt patterns, unites the ecological groups of marine and terrestrial, including mountain (n = 9), species. The glaucous-winged gull, Pacific swift, nutcracker, Siberian rubythroat, Middendorff's grasshopper warbler, Arctic warbler, Japanese bush warbler, American pipit, and masked bunting dominate in the population of forest and shrub habitats. The harlequin duck, glaucous-winged gull, black-legged kittiwake, Pacific swift, Asian house martin, American pipit, and Kamchatka wagtail dominate numerically in the population of the coast and adjacent sea area. In open sea areas, black-footed and Laysan albatrosses, the northern fulmar, the short-tailed shearwater, common murre, and tufted puffin are the most common. [ABSTRACT FROM AUTHOR]

Two morphological forms of larvae of Spirontocaris ochotensis (family Thoridae) in zoeal stages I–VI have been isolated from plankton. The main difference in the larvae of this species from the larvae of the other species of the genus Spirontocaris is the absence of a rostrum at all zoeal stages. The first form corresponds to the description of the larvae of S. ochotensis from the Gulf of Alaska. The second form differs in the larger size of zoeae II–IV, more numerous spines at the anteroventral margin of the carapace, more numerous aesthetascs in zoeae I–II, fewer setae on the scaphognathite of zoea I, more numerous setae on the basial endite of the maxillule in zoeae II–VI, more numerous setae on the coxal endite of the maxillule in zoeae II–VI, longer spines on the pleonal somites, and an earlier segmentation of flagellums of the antennule. It has been suggested that the second form is a subspecies of S. ochotensis that was previously described as S. makarovi spatula Kobjakova, 1936. [ABSTRACT FROM AUTHOR]