The South Sakhalin mud volcano (Sakhalin Island, Russia) emits HCO3-Cl/Na-Mg water, emanates CO2 prevailing over CH4 in the gas phase, and extrudes mud bearing five carbonate mineral species. The study focuses on the distribution, diversity, and origin of the carbonate minerals from the mud volcano (MV) ejecta, in terms of carbon cycle processes. The data presented include a synthesis of field observations, compositions of MV gases and waters, chemistry of carbonate minerals, as well as stable isotope geochemistry of MV waters (delta C-13, delta D, and delta O-18) and carbonates (delta C-13 and delta O-18). The sampled MV waters are isotopically heavy, with delta O-18 = +5.7 parts per thousand to +7.5 parts per thousand VSMOW, delta D = -18.0 parts per thousand to -11.0 parts per thousand VSMOW, and C-13 (delta C-13(DIC) = +6.9 parts per thousand to +8.1 parts per thousand VPDB). This composition may be due to the dilution of basinal water with dehydration water released during the diagenetic illitization of smectite. Carbonates in the sampled mud masses belong to three genetically different groups. Mg-rich siderite, (Fe0.54-0.81Mg0.04-0.30Ca0.05-0.23Mn0.00-0.08)CO3, disseminated in abundance throughout the mud masses, coexists with common calcite and sporadic ankerite. The trace-element chemistry of Mg-siderite, as well as the oxygen (delta O-18 = +34.4 parts per thousand to +36.8 parts per thousand VSMOW) and carbon (delta C-13 = -1.3 parts per thousand to +0.6 parts per thousand VPDB) isotopic signatures, confirms its authigenic origin. Siderite formed during early diagenesis of the Upper Cretaceous sandy and clayey marine sediments mobilized by mud volcanism in the area. Another assemblage, composed of dawsonite, siderite, and vein calcite (+/- kaolinite), represents altered arkose sandstones found as few fragments in the mud. This assemblage may be a marker of later CO2 flooding into the sandstone aquifer in the geological past. The trace-element chemistry, particular morphology, and heavy C (delta C-13 = +5.5 parts per thousand to +7.0 parts per thousand VPDB) and O (delta O-18 = +39.1 parts per thousand to +39.5 parts per thousand VSMOW) isotope compositions indicate that aragonite is the only carbonate species that is related to the current MV activity. It crystallized in a shallow reservoir and was maintained by CO2 released from rapidly ascending liquefied mud and HCO3-Cl/Na-Mg-type of MV waters.

Laser ablation combined with inductively coupled plasma mass spectrometry for the analysis of trace elements in specially prepared glass beads is adapted to silicate rocks of unusual compositions. The modified technique is applied to standard samples and garnet-rich combustion metamorphic rocks (paralavas) from the Hatrurim Formation, Israel. Thirty-two to thirty-five minor and trace elements, including high field strength elements, rare earth elements and Y, are determined in 5–8 mg powder aliquots of samples with large ranges of major-, minor-, and trace-element contents. As the first step of the study, the composition of the NIST SRM 612, BCR-2, and AGV-2 reference materials is analyzed to assess the accuracy and precision of analytical data. The results for standard samples agree well with the compiled estimates (3.5 to 12.4% relative standard deviation) for all elements except Cu (18.1%). The following step is to analyze, with the same procedure, the glass beads of paralava, which are remarkable due to their high trace-element loading. Good agreement (70–100%) with the compositions determined previously by aqueous nebulizer mode ICP-MS confirms that the method is a promising tool for the rapid and precise analysis of compositionally complex materials available in small amounts.

The influence of pressure on the incommensurately modulated structures has been poorly studied to date, particularly on the structures modulated at ambient conditions. Among them is the structure of natural flamite with the general formula (Ca,K,Na)2(Si,P)O4. The behavior of the incommensurately modulated structure of flamite was studied by single-crystal X-ray diffraction in a diamond-anvil cell up to 5 GPa. The modulation vector of flamite remains constant in the investigated pressure range. In the range up to 2-3 GPa, the atomic modulation parameters in the flamite structure are not sensitive to applied pressure, but at higher pressures, amplitudes of the atomic modulation functions increase. The PV-curve of flamite was fitted with the second-order Birch-Murnaghan equation of state: V0 = 350.8(7) & Aring;3, K0 = 85(9) GPa.

Andesites erupted by Kudryavy Volcano (Iturup Island, Kuril Arc, Russia) enclose porous vitreous Si-rich aluminous buchite xenoliths strongly depleted in Mg and Ca. The buchite samples have pseudoporphyritic microstructures and consist of abundant (up to 75 %) high-silica K-Al glass and high-temperature-low-pressure phases: <200 mu m anhydrous high-temperature silicate and oxide minerals including cordierite (X-Mg = 15-26 %), hercynite, tridymite, and intermediate members of the magnetite-ulv & ouml;spinel solid solution series, as well as minor plagioclase (An(41)Ab(53)Or(6) - An(15)Ab(70)Or(15)), anorthoclase (An(7-14)Ab(66-70)Or(19)(-)(25)), ilmenite, and rare Fe-bearing mullite, Fe-bearing corundum, cristobalite, intermediate members of the Fe23+TiO5 - (Mg,Fe2+)Ti2O5 -Fe2+Ti2O5 solid solution series, and chalcopyrite. The textures and mineral chemistry of the buchitic xenoliths evidence of bulk melting at temperatures of similar to 1000-1100 degrees C and subsequent quenching. Major- and trace- element data indicate that the host andesitic magma did not interact with the anhydrous silicate melts due to the high viscosity of molten xenolith material and the brevity of the thermal impact. The volcanic protoliths bear signatures of strong sulfate alteration of silicic and advanced argillic facies within the magmatic-hydrothermal system of the volcano conduit. Judging by the features of their mineralogy and chemistry, the sampled buchites originated from hydrothermally altered volcanic rocks which subsequently underwent extremely fast pyrometamorphism.

The morphology of calcium oxalate monohydrate precipitates (COM, Ca(C2O4)H2O, P2(1)/c, whewellite) occurring as crystals or intergrowths, as well as distribution of crystal-bearing idioblasts, have been studied for the first time in the bark of stone birch Betula ermanii from Sakhalin Island sampled in an area affected by mud volcanism and an unaffected typical forest environment taken for reference. The study addresses several issues (i) number and size of phytoliths and their distribution in different cell types; (ii) density of calcification in specific cells; (iii) habits of single crystals, twins, and complex intergrowths, as well as frequency of different morphologies and their relations. The trends of time-dependent morphological changes in separately analyzed crystals and intergrowths record the evolution of COM morphology from nuclei to mature grains. Of special interest are the nucleation sites and features of organic and inorganic seeds and nuclei for COM phytoliths. The precipitation process and crystal habits are mainly controlled by supersaturation, and it is thus important to constrain the Ca distribution patterns in different bark tissues. The B. ermanii samples were analyzed by several methods: scanning electron microscopy (SEM) for the distribution patterns and micromorphology of COM precipitates and bulk Ca content in bark; electron probe microanalysis (EPMA) for the mineral chemistry of COM precipitates; inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) for trace elements in bulk bark and wood. Research Highlights center dot The distribution and morphology of whewellite precipitates in the analyzed B. ermanii bark samples indicate that the aqueous solution was most strongly supersaturated with respect to the Ca(C2O4)H2O solid phase at the parenchyma-sclerenchyma boundary, where most of the COM spherulites are localized and often coexist with large single crystals and contact COM twins.

--Carbon and oxygen isotope compositions have been determined in (CO3)-groups of Ca carbonate-silicate minerals (spurrite, tilleyite, and scapolite) and calcite from samples of the Kochumdek contact aureole (East Siberia). The observed small delta 13C and delta 18O difference between the Kochumdek marbles and their protoliths (Delta delta 13C <= 1.5 parts per thousand and Delta delta 18O <= 2.0 parts per thousand) is consistent with moderate high-temperature metamorphic decarbonation of the protolith (0.1-0.2) and with almost absent metasomatic alteration in the aureole. Significant 18O depletion was inferred only for vein scapolite (delta 18O from +17.0 to +17.3 parts per thousand V-SMOW) and calcite from recrystallized limestone layers (delta 18O from +18.9 to +20.6 parts per thousand), which is evidence for limited infiltration of magmatic aqueous fluids from the cooling sill into the host sediments. The C and O isotope compositions of (CO3)-bearing spurrite and tilleyite show lower 18O depletion and insignificant 13C depletion relative to calcite, especially in highest-temperature merwinite marble (Delta delta 18OSpu-Cal = +3.3 parts per thousand; Delta delta 13CSpu-Cal = -0.8 parts per thousand). Gas chromatography-mass spectrometry (GC-MS) provided constraints on the relative percentages of H2O and CO2 in the fluid at highest-temperature spurrite-merwinite metamorphism. The fluid phase entrapped in calcite from merwinite marble is rich in CO2(XCO2=0.4-0.6).

Определен изотопный состав C и O в кальците и в (CO3)-группах карбонат-силикатов Ca(спуррита, тиллеита и скаполита) из пород Кочумдекского контактового ореола (Восточная Сибирь). Малые диапазоны различий между величинами δ13C и δ18O, характеризующие кочумдекские мраморы и их протолиты (Δδ13C ≤ 1.5 ‰ и Δδ18O ≤ 2.0 ‰), согласуются с низкой степенью высокотемпературной метаморфической декарбонатизации исходных мергелисто-карбонатных осадков (0.1—0.2) и отсутствием выраженных метасоматических изменений в породах ореола. Существенное обеднение изотопом 18O присуще только жильному скаполиту (δ18O от + 17.0 до + 17.3 ‰ V-SMOW) и кальциту из рекристаллизованных прослоев в известняках (δ18O от + 18.9 до + 20.6 ‰), что доказывает ограниченную инфильтрацию магматогенных водных флюидов из остывающего траппа внутрь вмещающей толщи. Определен изотопный состав C и O (CO3)-групп спуррита и тиллеита, которые обогащены изотопом 18O и могут быть несколько обеднены изотопом 13C относительно кальцита. Этот эффект максимален в наиболее высокотемпературных мервинитовых парагенезисах (Δδ18OSpu–Cal = + 3.3 ‰; Δδ13CSpu–Cal= –0.8 ‰). С применением метода беспиролизной газовой хромато-масс-спектрометрии (ГХ-МС) определены соотношения H2O и CO2 во флюиде при пиковых параметрах спуррит-мервинитового метаморфизма. Установлено, что флюидная фаза, законсервированная в кальците из мервинитовых мраморов, была богата CO2 (XCO2 = 0.4—0.6). Carbon and oxygen isotope compositions have been determined in (CO3)-groups of Ca carbonate–silicate minerals (spurrite, tilleyite, and scapolite) and calcite from samples of the Kochumdek contact aureole (East Siberia). The observed small δ13C and δ18O difference between the Kochumdek marbles and their protoliths (Δδ13C ≤ 1.5‰ and Δ?δ18O ≤ 2.0‰) is consistent with moderate high-temperature metamorphic decarbonation of the protolith (0.1–0.2) and with almost absent metasomatic alteration in the aureole. Significant 18O depletion was inferred only for vein scapolite (δ18O from +17.0 to +17.3‰ V-SMOW) and calcite from recrystallized limestone layers (δ18O from +18.9 to +20.6‰), which is evidence for limited infiltration of magmatic aqueous fluids from the cooling sill into the host sediments. The C and O isotope compositions of (CO3)-bearing spurrite and tilleyite show lower 18O depletion and insignificant 13C depletion relative to calcite, especially in highest-temperature merwinite marble (Δδ18OSpu–Cal = +3.3‰; Δ?δ13CSpu–Cal = –0.8‰). Gas chromatography-mass spectrometry (GC-MS) provided constraints on the relative percentages of H2O and CO2 in the fluid at highest-temperature spurrite-merwinite metamorphism. The fluid phase entrapped in calcite from merwinite marble is rich in CO2 (XCO2 = 0.4–0.6).

"Ovchinnikovite", a unique iron oxysulfide from the burned dumps of the Chelyabinsk coal basin (Ural, Russia), is a product of high-temperature (1000-1200 degrees C) alteration of xenoliths of siderite and ankerite rocks by the sulfide-rich gases emanating from the interior of the dumps. According to chemical and crystal-structure analysis, the compound is orthorhombic, with the chemical formula Ca4Fe32+Fe23+O6S4 (Z = 8). Among five Fe positions with octahedral coordination, two Fe3+ sites are bonded to four O and two S atoms each, while three Fe sites occupied by Fe2+ are bonded to two O and four S atoms each. The structure is based upon a three-dimensional framework of Fe-centered octahedra, with two types of layers alternating along the a axis. One layer type is built from corner-sharing Fe3+O4S2 octahedra (connected through O atoms). In the second layer, Fe2+O2S4 octahedra share faces and corners. S atoms connect the adjacent layers, and Ca atoms with 9-fold coordination are in between the layers. Density functional theory calculations indicate that Fe40Ca32O48S32 (i.e., Fe2.5Ca2O3S2) is a magnetic semimetal material. Other physical characteristics (spin magnetic moment; band structure; optical and dielectric properties) are presented. Crystal chemical relationships with synthetic Ca-Fe oxysulfides are discussed. Conditions of formation of "ovchinnikovite" are compared to those of rare oxysulfides in natural combustion metamorphic rocks as well as in metallurgical processes. The study of "ovchinnikovite" shows that man-made geochemical environments such as those occurring in burned coal dumps serve as another source of novel crystal chemistries almost unprecedented among synthetic systems.

We outline the results of mineralogical and geochemical analyses of Middle Pleistocene sediments of layer 21 in the Main Chamber of Denisova Cave, Altai. The aim of the study was to reveal a set of mineralogical and trace element markers of the black -colored horizons or lenses and to distinguish them from other types of cave sediments. Results were matched with those relating to a simi lar set of markers of black -colored horizons in the Holocene part of the section in the East Chamber. Results indicate probable sources of organic and organogenic substances in layer 21. The preservation of geochemical marks was assessed for Pleistocene in comparison with Holocene strata, where those markers are distinct. Black -colored lenses in layer 21 resemble biogenic sediments from Holocene section of the East Chamber. Both layers are characterized by high contents of N -bearing organic matter, P, Zn, Cu, and Cd. In bulk samples from Holocene sediments, numerous fragments of chitin (insect exoskeletons) and patches of newly formed Ca and Ca -Mg phosphates were found. We conclude that these peculiar lenses consist mostly of guano from insectivorous bats, and had undergone deep biodegradation. All bl ack-colored horizons and lenses studied in Denisova Cave have a similar set of geochemical markers and distinctly differ from the adjacent strata by their phase, macro- and trace element compositions.

The first data on chemical composition and Raman spectroscopy are given for a thiozincate phase from spurrite marbles at Tulul Al Hamam (Central Jordan). It is commonly associated with sphalerite to form overgrowths and replacements on ZnS (up to 20 µm). The empirical formula is (Na1.66K0.15Ca0.10Ba0.07)(Zn3.68Fe0.25Cd0.12)(S4.84Se0.12) (n = 77) that is close to ideal composition Na2Zn4S5 (Na2S•4ZnS). The phase is enriched in K, Ba, Fe and Se and mainly inherits variable concentration of Cd from parental sphalerite. The Raman spectra for Na2Zn4S5 are given in comparison with neighboring sphalerite. The main bands of the Na-Zn-sulfide are (in cm−1): 136, 146,150, 225, 255, 337, 345 and 357. This band suite differs from that of sphalerite. In general, the Na2Zn4S5 phase is a first natural Na-thiozincate and seems to be a new compound (Na2S•4ZnS) for the system ZnS-Na2S. It may be considered as a potential new mineral species.

We study merwinite and products of its retrograde exsolution (monticellite and spurrite) from marbles of a contact metamorphic aureole in the Kochumdek River area (East Siberia). Cooling to 820–880°C (at P ≈ 0.2 kbar and f_CO_2≫f_H_2O ) has led to pseudomorphic replacement of merwinite by monticellite-spurrite symplectites. Calculations show that most of the components (Ca, Mg, Mn, Fe, and C) are mobile in the reaction of merwinite exsolution while Si is inert. The inert behavior of silicon controls the process of replacement and restricts it to a few local sites. The formation of the monticellite-spurrite symplectites was maintained by the own resources of metacarbonates. Later, limited amounts of the monticellite-spurrite symplectites formed due to fluorine inputs, possibly, from the cooling intrusion.

Fe- and Al-rich metapelite from the Transangarian segment of the Yenisey Ridge (East Siberia, Russia) is a potential new source of high-alumina refractories. The rocks have relatively high average contents of Al2O3 (20 wt%) and Fe2O3 (7.91 wt%), moderate K2O (3.44 wt%), and low CaO (0.74 wt%). Their dominant mineral assemblages are andalusite + muscovite + margarite + chlorite + biotite + quartz or staurolite + kyanite or/and andalusite + chlorite + muscovite + biotite + quartz with ±garnet and ±plagioclase. Al2SiO5 polymorphs occur as up to 1.5 cm andalusite porphyroblasts and partial or complete pseudomorphs after andalusite (kyanite and staurolite). Accessories include abundant Fe–Ti oxides and sporadic REE-, Y-, Ca-phosphates; sulfides are negligible. The composition of Al2SiO5 concentrates obtained in laboratory by heavy-media and magnetic separation from ≥0.06 mm fractions meet all requirements for raw material of this type: >56 wt% Al2O3, <42 wt% SiO2, <1 wt% Fe2O3, <1.2 wt% TiO2, and <0.2 wt% (CaO + MgO). The andalusite, kyanite, and mixed ores yield 0.7–4.1 wt%, 0.7–2.2 wt%, and 1.9–6.0 wt% of concentrate, respectively. The best-quality ores rich in Al2SiO5 polymorphs reside in zones of contact and/or dynamic metamorphism superimposed over regional metamorphism of Al-rich rocks.

Сhromite-rich rocks and monomineralic chromitites occur in mafic-ultramafic layered intrusions worldwide, and are economically important as they host major resources of chromium and platinum group elements. One of the acknowledged genetic concepts for such mineralization advocates bulk chromite crystallization in a response to hybridization of Cr-rich basic magma with felsic melts, derived from partial melting of the wall rocks. However, there has been lack of direct insights into this process and its details have been remaining largely obscured. In this study, we report data on chromite-rich assemblages of the Noril'sk-1 intrusion (Siberian LIP), with a particular focus on chromite-hosted multiphase inclusions. Composition of the latter is different from the rocks of the Noril'sk-1 intrusion and inherits geochemical fingerprints of the wall rock argillites and, therefore, represent snapshots of the heavily-contaminated medium of the magma-wall rock reaction front. Mineral relationships in chromite-rich breccias with fragments of the wall rocks also provide valuable insight into chromite mineralization mechanisms. Our results, along with geological evidence and data on other Noril'sk-type intrusions, indicate that bulk crystallization of chromite, aided by partial suppression of silicate crystallization, occurred in the hybrid medium during digestion of the wall rocks by ascending and emplacing basic magma. Continuous flow of the magma around outshoots of the wall rocks or through a “magmatic karst” in the wall rocks, allowed for a continuous precipitation of chromite. Concentration of chromite grains to form dense mineralization apparently occurred due to formation of chromite-rich blobs around the wall rock fragments, and selective collection and transport of chromite by fluid bubbles, which formed via degassing of wall rocks and then carried chromite and relics of the wall rocks (xenoliths) to the upper parts of the pluton. We propose that assimilation-driven formation of chromite-rich lithologies in intrusions requires: (1) sufficient Cr contents in magma, which allow for its oversaturation in Cr-spinel only by a sudden cooling and addition of SiO2, K2O or/and H2O; (2) efficient disintegration and digestion of the host rocks, releasing considerable amounts of these components to the magma, and (3) a mechanism ensuring accumulation of excess chromite within a small volume (e.g. continuous reaction of Cr-rich magma with the products of the host rocks' assimilation or/and mechanical concentration of chromite).

Nitrogen storage capacity and partitioning between main N hosts have been investigated in N-bearing Al-rich natural pelite at 3.0-7.8 GPa, 825-1070 degrees C and oxygen fugacity (fO2) from NNO (Ni-NiO buffer)+0.3 to NNO-4.1 log units. Under the conditions of hot subduction, pelite converts into a phase assemblage typical of ultrahigh-pressure (UHP) eclogites. Phengitic muscovite in this assemblage is in equilibrium with a volatile-rich granite-like melt at 3.0 GPa and with supercritical fluid at 5.5-7.8 GPa, and contains, respectively, 115-135 and 759-962 wt ppm NH+4 at fO2 values close to NNO. Both melt and supercritical fluid have H2O and CO2 as predominant volatiles and the NH3/(NH3 + N2) ratio from 0.04 to 0.12. The pattern of nitrogen partitioning between its main hosts in pelite (DMs NH4 Melt = 0.41-0.58 and DMs  Fluid NH4 = 0.63-2.4) proves that the ammonium exhibits moderately incompatible to compatible behavior within a hot oxidized slab in the pressure range from 3.0 GPa to 7.8 GPa. Therefore, even relatively oxidized sediments containing phengitic muscovite can efficiently transport nitrogen to the mantle at sub-arc depths under the hot subduction conditions. At the same time, the changeover of the N host from biotite to muscovite at the arc depths in combination with subsequent pelite melting and an abrupt decrease in phengitic muscovite abundance in pelite may lead to an avalanche-like N outgassing of the slab. The incorporation of an additional nitrogen source of (NH3 + N2) into pelite reduces fO2 to NNO-3.1 - NNO-4.1 log units and increases both the NH3/(NH3 + N2) ratio in the fluid (up to 0.44-0.86) and the NH+4 concentration in phengitic muscovite (up to 3750-3820 wt ppm). K-cymrite was produced in pelite at P & GE; 6.3 GPa and the bulk nitrogen content 3.2-5.9 wt%. K-cymrite possesses exceptional nitrogen storage capacity: it hosts 1.4-1.6 wt% NH+4 , up to 0.5 wt% NH3, and 4-6 wt% N2. The DCym  Ms stable in sediments subducted to mantle depths, K-cymrite, with its extremely high storage capacity, can act as a huge hidden redox-insensitive nitrogen reservoir in the mantle and thus can be involved in the deep nitrogen cycle.

The violent eruption of Karabetova Gora mud volcano on 6 May 2000 (Taman Peninsula, 45°12′16″ N; 36°47′05″ E) triggered gas ignition as a giant straight-flow vertical gas flare. The 400 m high, short-lived (~15 min) gas flare left no thermal halo on the ground surface, but the thermal shock caused melting or annealing of mud masses which became dispersed in ≤2 m3 blocks to distances within 30 m around the volcano conduit. The flare reached the maximum temperatures (~1400–1540 °C) at heights from 75 to 250 m, as estimated by a numerical simulation in SigmaFlow. Bulk melting of dehydrated mud masses was mostly limited to <1.5 cm near the surface of the blocks. Porous paralavas at the site consisted of low- and high-silica K-Al glasses (70%–80%) with residual unmolten grains of detrital quartz and fine (<30 µm) new phases: main intermediate members of the magnetite–ulvöspinel solid solutions and plagioclase (An45-61Ab37-44Or2-11 to An73-90Ab10-27Or0.5-1), minor cordierite (XFe = 26%–46%), pigeonite (XFe = 42%–60%), tridymite, cristobalite, and rare mullite. The metapelitic rocks affected by combustion metamorphism were heterogeneous in terms of phase composition and texture. They failed to attain homogeneity due to the high viscosity of anhydrous silicate melts and brevity of the thermal impact. The revealed features of rocks altered by a giant gas fire may serve as a proxy for phase transformation patterns in highly disequilibrium conditions of a thermal shock, far from the formation conditions of ordinary metamorphic rocks.

The Kurai Fault Zone (KFZ) is one of the most hazardous seismogenic structures in the Gorny Altai (Russia), which bounds the largest Kurai and Chuya intermontane basins from the north. Trenching studies, radiocarbon dating of colluvial wedge deposits, and 230Th-U dating of seismogenic travertine of the Meshtuyaryk field showed that the fault scarp in the northwestern part of the Chuya Depression was formed by earthquakes that occurred ca. 9.5, 7.7, 5.8, and 4.8–3.4 ka BP. The last two palaeoearthquakes are younger than 3.2 ka BP. The parameters of seismogenic ruptures, as well as the distances between coeval seismogenic travertines along the KFZ, yielded estimates of the Mw of the four oldest palaeoearthquakes as 6.8–7.6 and ESI 2007 shaking intensities of VIII–XI. The results of 230Th-U dating suggest that deposition of the Meshtuyaryk travertines was triggered by three strong palaeoearthquakes at ca. 9.5, 7.7, and 4.8–3.4 ka BP, which activated faults and caused a rapid rise along them of ambient-temperature bicarbonate groundwaters previously sealed in deep-seated limestone aquifers.

Research subject. Аndalusite- and kyanite-bearing (13–19 wt % Al2SiO5) rocks of the Teya metamorphic complex (Mayakon and Panimba areas), Yenisei Ridge. Aim. To study the composition and mineral content of high-alumina rocks from the Panimba and Mayakon areas. Materials and methods. Laboratory mineral processing was employed to estimate the mineral content of metamorphic rocks of the Teya complex using a magnetic and gravity separation at the Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences (Novosibirsk). The concentrates were obtained from typical samples of andalusite, kyanite, and andalusite-kyanite metapilites. After crushing and grinding, the rock samples were separated into size fractions <0.06, 0.06 ≤ x < 0.1 and 0.1 ≤ x < 0.25 mm. The concentrates were recovered from size fractions ≥0.06 mm. Phase, bulk rock, and trace element composition of the rock samples, mineral concentrates, and other fractions were analyzed using XRD, XRF, ICP-MS, and SEM. Results. The magnetic product obtained at the first stage of mineral processing using magnetic separation accumalated staurolite, biotite, chlorite, ilmenite, pyrrhotite, and pyrite. At the second stage, light products containing quartz, feldspars, and muscovite were separated from non-magnetic products with CHBr3 using a centrifugal concentrator. At the last stage, using a double-knife separator, the heavy product from the previous beneficiation stage was separated into a “magnetic” raw concentrate (52–92 wt % Al2SiO5) and a “non-magnetic” final (70–97 wt % Al2SiO5) concentrate. The andalusite-kyanite concentrates (up to 97 wt % Al2SiO5) were obtained by the combination of cheapest and simplest methods of magnetic and gravity separation. The concentrates containing andalusite and kyanite with low recovery (0.7–6%) are comparable to the grade of kyanite-bearing ores of Karelia, the Kola Peninsula, and Gansu Province, China. Conclusions. The study shows that high-quality andalusite and/or kyanite concentrates can be recovered from high-alumina metapelites of the Teya metamorphic complex.

The south-eastern Gorny Altai is one of the most hazardous seismogenic area in the north of Central Asia. We present a synthesis of field, 230Th-U geochronological, mineralogical and geochemical data collected on seven Quaternary travertines. All travertines occur within the zones of active faults that border the Chuya and Kurai intermontane basins. Travertine cement mainly comprises calcite (with minor amounts of aragonite), which cements alluvial, alluvial fan, and colluvial deposits. The results of 230Th-U dating suggest that deposition of the travertines was triggered by large paleoearthquakes in the last eight thousand years. Several stages of travertine formation with ages 9–11 ka BP correspond to the known period of strong paleoseismicity in the region (8–16 ka BP). The 123 ka BP travertine resulted from a slip triggered by the Middle Pleistocene deglaciation, while that of 400 ka BP represents seismic motions likely associated with the main Cenozoic orogenic phase. All travertine forming events fall within warm and wet climatic phases (interglacials). Large earthquakes activated faults and caused a rapid rise along them of ambient-temperature bicarbonate groundwater, which was previously sealed in deep-seated Upper Neoproterozoic–Paleozoic limestone-dolostone aquifers. Rapid CO2 degassing of the spring water was the most important control of calcite or aragonite precipitation. Such travertines represent an important tool for paleoseismological research in seismically active regions.

В статье приводятся предварительные результаты изучения и характеристика проявлений процессов неотектоники в Денисовой пещере, их влияния на формирование и постседиментационные изменения плейстоценовых пещерных отложений. В Денисовой пещере следы палеоземлетрясений рассматриваются в разрезах осадочных толщ центрального зала, восточной и южной галерей. Описаны основные типы сейсмогенных деформаций. Дается хронологическая оценка эпизодов древних сейсмических событий, запечатленных в стратиграфической последовательности пещеры. Установлено, что смещения слоев в результате сейсмических деформаций оказались незначительными, и их границы хорошо коррелируются. Не происходило смешения вещества разных литологических подразделений и соответственно содержащихся в них палеолитических и палеонтологических материалов. Предполагается, что неотектоническая активность могла оказывать влияние на условия обитания первобытного человека как один из факторов природной среды.