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Mercury speciation and the composition of mercury phases in natural and mining-related environments is studied by the thermal release analysis combined with electrothermal atomic absorption spectroscopy (TA-ET-AAS), as well as scanning electron microscopy with energy-dispersive X-ray microanalysis (SEM-EDS). The analyses are applied to laboratory-made samples bearing mercury selenide and to field samples from sites known for relatively high natural or industrially induced Hg background. They are, namely, material from the dispersion train of the Ursk sulfide tailings (Ursk Village, Kemerovo region) and debris precipitated from snow sampled in the Kurai mercury zone (Aktash Village, Gorny Altai). The TA-ET-AAS method works well in discrimination and identification of Hg sulfide and Hg selenide provided that the samples contain sufficient amounts of both compounds, but the sum HgS + HgSe can be determined at any contents of the two compounds. The presence of both mercury sulfide and mercury selenide in the samples has been confirmed by SEM-EDS microanalysis. The temperature ranges for the mercury species (Hg2+; HgS+HgSe mixture; mercury bound with organic matter (Hg-OM), including CH3Hg+) are identical in the laboratory and field samples. Therefore, the suggested approach can ensure fast and reliable detection of Hg phases in rocks exposed to supergene alteration

The paper presents the results of determination of the ore contents of rare earth elements (REE) in geological samples by atomic emission spectrometry with arc two-jet plasmatron, which allows to analyze solid-phase samples asa fine powders. We studied a niobium-rare earth ore sampled at the Buranniy site of the Tomtor deposit (Arctic Siberia, Russia). The results for all REEs, except for Tb, Yb and Lu, are consistent with the ICP-MS data. It is shown that the use of several analytical lines at the same time in the determination of REE significantly increases the determination accuracy and reliability of the results

Data indicating the important role of microorganisms in the redistribution of REEs in the weathering crust and the decisive role in the concentration of REEs during the formation of ores in the upper ore horizon of the Tomtor field are obtained. The uptake of REEs was carried out by the community of microorganisms, such as phototrophs, methanogens, methanotrophs, and proteobacteria, which form the basis of the microbiocenosis for this paleoecosystem. The isotopic composition of C carbonates in all samples studied with fossilized microorganisms corresponds to the biogenic one, and the isotopic composition δ18ОSMOW (from 7 to 20‰) indicates the endogenous (hydrothermal) and, to a lesser extent, exogenous nature of the solutions. The low (87Sr/86Sr)I values of carbonates (~0.7036–0.7042) exclude the participation of seawater.

Influence of sample pretreatment on the analysis of the high contents of rare earth (REE) and high field strength (HFSE) elements in geological samples by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) was studied. The rocks and rich ores of the Tomtor Nb-REE deposit were explored. Complete dissolution of the geological samples with a high content of “refractory” minerals has been achieved using fusion with a sodium peroxide. The results obtained by ICP-AES and ICP-MS after chemical dissolution are comparable with the results obtained by the XRF-SR without chemical pretreatment

Among the rich REE–Nb ores of the upper ore horizon of the Tomtor deposit, under the Jurassic deposits (borehole 324, interval 47–62 m), ultrapotassiс rocks (feldspar porphyrite), consisting of more than 90% potassium feldspar (K-feldspar), are found. The rocks contain titanium–niobium oxide and rare grains of fersmite, Ce-bastnaesite, Ce-monazite, calcite, barite, and strontianite. K-feldspar is unevenly replaced by muscovite. By the type of REE and element distribution on the multidiagrams, the rock correlates well with the rich REE–Nb ores from the Burannyi site at the lower levels of contents. The Ar–Ar age of K-feldspar corresponds to 323.4 Ma and is correlated with the geological time of the formation of the rich REE–Nb ores from the Tomtor deposit, as well as the time of occurrence of magmatic and hydrothermal activity in this part of the region during this period.

Carbonates of the Tomtor complex of ultramafic alkaline rocks and carbonatites (the northern part of the Republic of Sakha Yakutia) are distinguished by a wide range of carbon isotopic composition δ13C from +2 to –59.9‰. The geological position, localization patterns, mineral and chemical compositions and the relationship with REE mineralization of samples with values of δ13C carbonates from –25 to –59‰ are characterized. The formation of abnormally low δ13C in carbonates is determined by the biogenic oxidation of methane from δ13Cmet to –70‰.

The experimental study is aimed at elucidation the laws of Au sorption/deposition by various natural sorbents in an acidic environment (pH=2). The experiments simulated the conditions of the dispersion train of the Ursk tailings (Kemerovo region, Russia), where active concentration of Au by natural organic matter in an acidic environment is observed. It was found that the degree of extraction of gold from a sulfate solution is generally higher than from chloride solution. This may indicate higher thermodynamic stability of Au chloride complexes in an acidic environment than sulfate ones. Higher deposition rates of gold are observed in solutions with a predominant content of sulfate ions. According to the degree of deposition of Au, a series was established (from larger to smaller): a mixture of clay minerals (smectite + palygorskite + muscovite) > humic acids > kaolinite

Paleoreconstruction of events involved in the bottom sedimentation has been carried out on the basis of mineral composition of the section of the minor lake IV (Lake Fumarolnoe, Kamchatka) bottom sediments. The lower sediments are composed mainly of smectite in association with gypsum and jarosite; they are overlain by smectite–kaolinite with a large amount of framboidal pyrite and diatom shells. There is also a layer of sinter opal–pyrite units and calcite. It is concluded that initially the minor lake IV was a mud pit with sulfide-bearing solutions. Then, after the lowering of the water level and the partial exposure of the bottom sediments on the surface, the latter were oxidized. The subsequent phreatic explosion provided the covering of oxidized sediments with the reduced substance from the lower horizons of the pit. Further setting of sediment accumulation corresponded to a source with cyanobacterial community developing around the gryphon, and then it changed to that of a shallow-water lake similar to a contemporary one. Sediments also include two layers of pyroclastic material originated from eruptions of neighboring volcanoes.

In the northern part of the Siberian Platform, east of the Anabar Shield, several massifs of alkaline rocks with carbonatites identified (Tomtor, Bogdo, Promezhutochnyi) and projected according to geophysical data (Bualkalakh, Chuempe, Uele) form a large alkaline–carbonatite province. The first data on the composition of alkaline rocks of the Bogdo massif indicate that the latter belong to a group of feldspathoid rocks of basic composition: rischorrites, biotite–aegirine liebenerite syenites, carbonatized pseudo-leucite nepheline syenites with symplectites, and nepheline–feldspar aggregates. Sphene grains were extracted from various rocks of the Bogdo massif, and their U‒Pb age was determined using the SHRIMP-II secondary-ion microprobe. The calculated U‒Pb age is 394.4 ± 3.2 Ma, which is similar to the age of the Tomtor massif and the age of the rocks of the Kola alkaline province. One of the reasons for the manifestation of alkaline plume magmatism on this territory may be the effect of the peripheral zone of the African Large Low Shear Velocity Province (“Tuzo”) on the Baltic area and Siberia during the Devonian age.

The paper presents data on two cores from the dispersion train of gold-bearing sulfide tailings in the Novo-Ursk deposit (Kemerovo region, Russia), where organic-bearing mud and natural organic matter are interbedded with cyanide tailings and acid mine drainage (AMD). The study focuses on speciation of Au, Ag and potentially toxic elements (PTE), including Fe, Cu, Zn, As, Se and Pb according to selective sequential extractions. Since large contents of elements are found in water solution and bound to Fe(III) compounds, sulfides and/or organic matter in both cores, the organic material behaves as a natural biogeochemical barrier for potentially toxic elements and precious metals released from AMD. The interaction with organic matter results in biogeochemical sorption and immobilization of elements and is favourable for secondary enrichment in gold and silver. It leads to immobilization of elements that further form new mineral phases or become partitioned between existing phases. On the other hand, very high concentrations of water-soluble and oxidizable species of PTE and Au, which are unstable in surface conditions and may become remobilized when the environment changes, make the organic material less workable and even potentially hazardous. Thus, both positive (secondary enrichment) and negative (pollution) effects should be taken into account in the planning and design of systems for purification, disposal of cyanide tailings and recovery of useful components from tailings using natural organic matter as a geochemical barrier.

Paleoreconstruction of events involved in the bottom sedimentation has been carried out on the base of mineral composition of a section of bottom sediments in the Lake IV (the Lake Fumarolnoe). The lower levels are composed there mainly of smectite in association with gypsum and jarosite; they are overlapped by smectite-kaolinite depositions with the large amount of diatom algae shells and the fraboidal pyrite. There is also a layer of sinter opal-pyrite structures and calcite. It is assumed that initially the lake IV was a mud pit with sulfide-bearing solutions, then, after the lowering of water level and the partial exposure of bottom sediments of the surface, the substance has been oxidized. The subsequent phreatic explosion has provided the covering of oxidized substance by the matter of lower layers of the pit. The further situation corresponded to the source, with the cyano-bacterial community developing around the griffin, and it was replaced by the site of a shallow-water lake similar to the contemporary one. The studied sedimentary formation includes two layers of pyroclastic material originated from neighbouring eruptions.

Below is data on the microbial diversity of natural organic matter from the Dispersion Train of Sulfide Tailings (northern Salaire Ridge, southwestern Siberia, Russia, Ursk Village). Data was obtained using 16s rRNA amplicon directed metagenomic sequencing on Illumina MiSeq. The raw sequence data used for analysis is available in NCBI under the Sequence Read Archive (SRA) with BioProject No. PRJNA670045 and SRA accession number SRX9314152, SRX9314376. The data sequences of the 16s rRNA gene are presented at the links MW142408-MW142413, MW142414-MW142447.

In the Eastern margin of the Anabar shield the Proterozoic alkaline pipes, dikes, and stocks are widespread. The largest Talakhtakh diatreme cut Middle-Upper Riphean dolomites (MP3-NP2) at the left bank of Kuonamka River (Fig. 1). The Talakhtakh diatreme includes alkaline basaltoids, ultra-K-trachytes, lamproites, olivine leucitites, tephrites, (Vishnevsky et al., 1986). TRE distribution indicates the proximity of sanidine trachytes to lamproites. The 40Ar/39Ar laser dating show two age maxima 1476 ± 17 (N = 14) and 1321 ± 17 (N = 9) Ma. If 10 points form a linear regression, with an age value of 1497 ± 40 million years, an initial ratio of 189 ± 100, then most of the remaining points are located along the abscissa axis. This arrangement may be associated with different degrees of rejuvenation of the K/Ar isotope system within the dating sites. The weighted average of 1476 ± 17, as more accurate, corresponds to the age of sample formation.Ernst et al (2016) identified a new Kuonamka Large Igneous Province (LIP), based on U-Pb dating of baddeleyites from dolerite dikes and sills of the Anabar shield. The age of Kuonamka LIP is ~ 1501 ± 3 Ma. The resulting 40Ar/39Ar is the age of leucite trachytes (lamproites) The Talakhtakh diatreme fully corresponds to the time of occurrence of the Kuonamka LIP and indicates the formation of high-K effusions of the Talakhtakh complex during this period.This work supported by RFBR grants: No. 18-05-70109 and the Russian Ministry of Education and ScienceGusev N.I., et al. State Geological Map of the Russian Federation. Sheet R-49-Olenek. An explanatory Memorandum. Saint Petersburg: Map factory VSEGEI. . 2016. 448 с.Vishnevskiy S.A., Dolgov Yu. A., Sobolev N. V. Geology&Geophysics, 1986. № 8. P. 17-27.Ernst R. E., Okrugin A.V. et al. Russian Geology&Geophysics. 2016. № 5. P. 653,-671.

Below is data on the microbial diversity in bottom sediments and microbial mats in water bodies within the Kurai Mercury Province (Ulagan District, Aktash village, Gorny Altai). A database on the geochemical features of water bodies in the study area is presented. Data was obtained using 16 s rRNA amplicon directed metagenomic sequencing on Illumina MiSeq. The raw sequence data used for analysis is available in NCBI under the Sequence Read Archive (SRA) with BioProject No. PRJNA670076 and SRA accession numbers SRX9316205, SRX9316207, SRX9316208, SRX9316209.

We study the contents of elements and group composition in natural organic matter (NOM) that interacts with acid mine drainage (АMD) and high-sulfide tailings at the Ursk site (southwestern Siberia, Russia). AMD causes biomass changes in NOM, related changes in the composition of fractions, and hydrolysis of hydrolyzable compounds; it increases the water-soluble fraction and maintains depolymerization of humic acids to fulvic acids, but exerts no effect on substances soluble in organics (bitumen) or on poorly hydrolyzable compounds. Accumulation of inorganic elements and precipitation of minerals obscure the true fraction composition of NOM: the superposed mineral component contributes significantly to the water-soluble, humic acid, hydrolyzable and non-hydrolyzable fractions, and may reach 26.4% per total of all fractions. Rock-forming and potentially toxic elements partition among NOM fractions and predominate in the water-soluble fraction. The contents of Au and Ag are the highest in the fractions of humic acids and hydrolyzable compounds but are lower in the non-hydrolyzable residue. The obtained data have implications for possible migration of potentially toxic elements and noble metals and thus for remediation of polluted areas. The observed fractionation of Ag and Au in NOM helps us to understand the mechanisms of their distribution in organic-bearing environments, such as peatlands or coal basins.

В настоящее время в России происходит трансформация миграционных потоков, временный характер миграции меняется на постоянный. Основная доля мигрантов прибывает из стран Центральной Азии, где демографическая и экономическая ситуация приводит к долгосрочному росту потоков трудовых мигрантов. В этих условиях актуализируются вопросы их адаптации и интеграции. Исследование представляет собой обзор научной литературы, изучающей адаптационные практики трудовых мигрантов. Сравнительный анализ обусловлен важностью использования накопленного опыта европейских стран, которые проводят политику активной интеграции мигрантов. Поиск публикаций, отражающих вопросы изучения факторов и моделей адаптации трудовых мигрантов из Центральной Азии в России и странах Европейского союза, осуществлялся на площадках Scopus, Web of Science, e-Library. Выявлены возросший интерес к теме исследования, рост публикационной активности и увеличение количества совместных исследований данной проблематики представителями разных стран. В большинстве случаев исследователи отмечают роль социального капитала в адаптации мигрантов, длительность процесса аккультурации мигрантов и важность участия принимающего сообщества в этом процессе. Рассматривается опыт двусторонней адаптации в странах ЕС. По мере увеличения потока мигрантов в страны ЕС из Центральной Азии интерес западных исследователей к этой теме будет расти. Результаты исследования могут быть использованы для повышения эффективности изучения миграционных процессов. Currently, the Russian Federation is experiencing a transformation of migration flows from temporary to permanent. The largest share of migrants comes from the countries of Central Asia, where the demographic and economic situation stimulates a long-term increase in flows of labour migrants. In these conditions, it is necessary to examine issues of adaptation and integration of migrants. We review scientific literature on the adaptation practises of labour migrants. We applied the method of comparative analysis due to the importance the accumulated experience of European countries, which chose a policy of active integration. We analysed scientific publications, which are indexed in Scopus, Web of Science, E-library databases, and focused on the factors and models of adaptation of labour migrants from Central Asia in Russia and the countries of the European Union (EU). The study revealed the growing interest in the research topic, increased publication activity and joint research by representatives of different countries. In most cases, researchers note the role of social capital in the adaptation of migrants, the length of the acculturation process of migrants and the importance of participation of the host community in the process. We proposed to consider the experience of bilateral adaptation in the EU countries. As the flow of migrants to the EU countries from Central Asia increases, the interest in this topic on the part of Western researchers will grow. The research results can be used to improve efficiency in the research of migration processes. The article has been prepared with the support of Russian Foundation for Basic Research, the project No. 19–110–50312.

Background The Uzon Caldera is one of the places on our planet with unique geological, ecological, and microbiological characteristics. Uzon oil is the youngest on Earth. Uzon oil has unique composition, with low proportion of heavy fractions and relatively high content of saturated hydrocarbons. Microbial communities of the «oil site» have a diverse composition and live at high temperatures (up to 97 °C), significant oscillations of Eh and pH, and high content of sulfur, sulfides, arsenic, antimony, and mercury in water and rocks. Results The study analyzed the composition, structure and unique genetics characteristics of the microbial communities of the oil site, analyzed the metabolic pathways in the communities. Metabolic pathways of hydrocarbon degradation by microorganisms have been found. The study found statistically significant relationships between geochemical parameters, taxonomic composition and the completeness of metabolic pathways. It was demonstrated that geochemical parameters determine the structure and metabolic potential of microbial communities. Conclusions There were statistically significant relationships between geochemical parameters, taxonomic composition, and the completeness of metabolic pathways. It was demonstrated that geochemical parameters define the structure and metabolic potential of microbial communities. Metabolic pathways of hydrocarbon oxidation was found to prevail in the studied communities, which corroborates the hypothesis on abiogenic synthesis of Uzon hydrothermal petroleum.

A comprehensive research of water and cyanobacterial mats in Mogoysky and Shurindinsky thermal springs (Baikal rift zone) was carried out by hydrochemical, chemical, microbiological, and mineralogical methods. Detailed descriptions of the springs location and their characteristics were given. According to their chemical composition, the springs were classified as fluoride-bicarbonate (Mogoysky) and bicarbonatesulfate (Shurindinsky) types with a high concentration of fluorine. This is explained by the interaction of infiltration waters with embedding rocks. A wide diversity of cyanobacteria (14 species of 7 genera) was revealed in the investigated springs. The development of cyanobacteria in microbial mats was observed at water outflows at the temperatures of 37.8 to 76.6°C. Chlorophyll a was the predominant pigment in microbial mats of the studied springs, indicating predominance of cyanobacteria in the mat. Deposition of various pyrite forms, celestite (SrSO4), fluorite (CaF2), calcium carbonate, elemental sulfur, barite, and amorphous silica was found in microbial mats.

Migration and redistribution of elements during prolonged interaction of cyanide wastes with the underlying natural organic-bearing material have been studied in two ~ 40 cm deep cores that sample primary ores and their weathering profile (wastes I and II, respectively) in the dispersion train of gold-bearing sulfide tailings in Siberia. Analytical results of SR-XRF, whole-rock XRF, AAS, CHNS, and SEM measurements of core samples show high K, Sr, Ti, and Fe enrichments and correlation of P2O5 and Mn with LOI and Corg. Organic material interlayered or mixed with the wastes accumulates Cu, Zn, Se, Cd, Ag, Au, and Hg. The peat that contacts wastes II bears up to 3 wt.% Zn, 1000 g/t Se, 100 g/t Cd, and 8000 g/t Hg. New phases of Zn and Hg sulfides and Hg selenides occur as abundant sheaths over bacterial cells suggesting microbial mediation in sorption of elements. Organic-bearing material in the cores contains 10–30 g/t Au in 2–5 cm thick intervals, both within and outside the intervals rich in sulfides and selenides. Most of gold is invisible but reaches 345 g/t and forms 50 nm to 1.5 μm Au0 particles in a thin 2–3 cm interval of organic remnants mixed with wastes I. Vertical and lateral infiltration of AMD waters in peat and oxidative dissolution of wastes within the dispersion train of the Ursk tailings lead to redistribution of elements and their accumulation by combined physical (material's permeability, direction AMD), chemical (complexing, sorption by organic matter and Fe(III) hydroxides) and biochemical (metabolism of sulfate-reducing bacteria) processes. The accumulated elements form secondary sulfates, and Hg and Zn selenides. The results provide insights into accumulation of elements in the early history of coal and black shale deposits and have implications for remediation of polluted areas and for secondary enrichment technologies.

We study a unique deposit of Nb-REE ores that occur as three orebodies overlying weathered rocks of the Tomtor ultramafic alkaline-carbonatite complex in the northern Sakha Republic (Yakutia). The formation conditions of the rich Tomtor ores remain poorly constrained. Our hypothesis is that these ores, composed of detrital and authigenic minerals, were deposited in a hydrothermal lake. The Eh-pH parameters of water are reconstructed from REE distribution in ores and in monazite, with reference to results of thermodynamic calculations. The stability fields of hydrous Ce, La, and Nd phosphates in the Pourbaix diagrams are proximal in a region within a small range of pH (4-6) and Eh (-0.25 -+0.25 V). Monazite apparently formed by dehydration of the precursor phase of hydrous REE phosphate. This inference is supported by coexistence of Fe3+ and Fe2+ minerals.

The mineralogy (SEM), geochemistry (LA-ICP-MS) and isotopic composition of C, O and Sr in carbonates from uniquely high-grade REE-Nb ores of the Tomtor massif is presented. Testing of the formation conditions for uniquely high-grade ores from the Tomtor deposit was conducted.

Natural organic matter (NOM) within the dispersion train of Novo-Ursk tailings (Salair Ridge, Kemerovo region, Russia) is composed of remnant sedge peat mounds and is located either on the surface or is buried under cyanide wastes. The organic material interacts with AMD and with the wastes, which leaves imprint on its composition. This interaction produces geochemical anomalies (g/t: 1582 Cu, 41,300 Zn, 6060 Se, 11,700 Hg, 114-155 Au, 534 Ag, 416 I). The contents of elements depend on Fe in three groups of NOM samples that contain10 wt% Fe (group I), 10-22 wt% Fe (group II), and22 wt% Fe (group III). NOM with higher Fe enrichment contains less Cu, Zn, Se, Hg, Ag and I, as well as Cd, Ba, Sr and Rb, Y, Zr, Nb, Mo, Sn, Sb, and Te but more As. Yet, gold may reach high concentrations in NOM with any Fe contents. Accumulation of elements by NOM during its prolonged interaction with wastes and AMD is maintained by physical, chemical, biochemical, and mineralogical processes. They are, respectively, migration of waters controlled by permeability of material in the dispersion train depending on its grain sizes and by AMD flow direction; oxidative dissolution of sulfides, complexing, and adsorption on organic matter and Fe(III) hydroxides; microbial mediation; and secondary mineralization. The chemistry of waters interacting with NOM at the time of its deposition can be reconstructed with regard to several factors, including microbial mediation. Namely, local geochemical anomalies with ultrahigh element concentrations may arise because microorganisms can immobilize Hg to make it less toxic; sulfate-reducing bacteria can maintain precipitation of Zn, Cu, and Cd sulfides; microbial activity can mediate redistribution of elements between clastic and organic materials, etc. The inferred inheritance of AMD geochemical signatures by NOM has implications for the conditions and mechanisms of element accumulation.

This is data on the microbial diversity in the floating cyanobacterial community and sediment samples from the lake Solenoe (Novosibirsk region, Russia) obtained by metagenomic methods. Such a detailed data of the microbial diversity of the Novosibirsk oblast lake ecosystem was carried out for the first time. The purpose of our work was to reveal microbial taxonomic diversity and abundance, metabolic pathways and new enzyme findings the studied lake ecosystem using the next-generation sequencing (NGS) technology and metagenomic analysis. The data was obtained using metagenomics DNA whole genome sequencing (WGS) on Illumina NextSeq and NovaSeq. The raw sequence data used for analysis is available in NCBI under the Sequence Read Archive (SRA) with the BioProjects and SRA accession numbers: PRJNA493912 (SRR7943696), PRJNA493952 (SRR7943839) and PRJNA661775 (SRR12601635, SRR12601634, SRR12601633) corresponding to floating cyanobacterial community and sediment layers samples, respectively.

More than eighty years of mining at the Novo–Ursk Au-bearing sulfide field (Kemerovo region, Russia) have produced a mixed natural–industrial system “wastes–gold-bearing acid mine drainage (AMD) waters–peat”. The behavior of Au, Ag and related elements in the system “wastes–AMD” is described in Part 1 of our study (Myagkaya et al. 2016 ) where we discuss interaction between the gold-bearing mine drainage waters and peat. This interaction leads to rapid accumulation of Ca, Fe, Mn, Ba, Cu, Zn, Se, Au, Ag, Hg, Pb to concentrations exceeding those in cyanidation wastes (especially, Cu, Zn, Se, Hg, and Pb). The contents of Au (about 5 ppm on average, locally as high as 155 ppm) and Ag (average about 11.2 ppm, locally up to 560 ppm) in peat are above the lowest economic values. These results provide clues to technologies for both generation of secondary gold (silver) deposits at existing or planned tailings and immobilization of toxic elements. Gold is accumulated in peat by a series of processes (reduction of ion gold to elemental form, sorption by complexation, biochemical reactions, etc.). This secondary gold is mostly chemically bound and invisible and a minor part is nanoparticulate (from tens of nm to 1.5–4 μm particles; with 7.5–53‰ Cu); it coexists with barite, secondary pyrite, tiemannite, Hg and Zn sulfides. Silver becomes redeposited in peat as silver-bearing sulfides and selenides. The presence of fossil bacterial fragments points to microbially mediated physicochemical processes leading to sulfide and gold mineralization by sulfate reduction and biosorption. Formation of abundant gold and mercury minerals may be due primarily to microbial activity. Peat in the area of the Ursk tailings is actually a prototype of coalbeds. Therefore, the mineralogical and geochemical patterns of gold and silver reprecipitation on organic matter, and the respective Au and Ag enrichment, provide insights into the early history of gold mineralization in coal.

Wastes of the ore cyanide process are prone to oxidation and acid leaching that cause mobilization, migration, and precipitation of elements, including noble metals. The issues of waste oxidation, as well as release and transport of oxidation products, are of principal environmental concern and a focus of active geochemical research. We study the behavior of Au and Ag in the natural–industrial system “sulfide wastes–surface/pore waters–particulate matter–bottom sediments” in the presence of different elements (Na, Mg, K, Ca, Al, Fe, Cu, Zn, Se, Ag, Au, Hg, Pb, REE, etс.), at the Novo-Ursk auriferous pyritic deposit (Salair, Kemerovo region, Russia). The wastes include processed primary ore (wastes I) and ore from the gold-bearing weathering profile (wastes II) that store, respectively, 0.5 ppm Au, 18 ppm Ag and 0.26 ppm Au, 13 ppm Ag. Gold in wastes I occurs in the native form with Cu and Ag impurities and also Au exist as invisible species in pyrite. In wastes II, gold is adsorbed onto the surfaces of secondary mineral particles (kaolinite, montmorillonite, hydromica, and Fe(III) compounds) while silver is an isomorphic impurity in alunite–jarosite minerals. The oxidation of wastes produces acid mine drainage (AMD) water, with рН = 1.9 and high concentrations of sulfate, Fe, Al, Cu, Zn, Pb, As, Se, Te, Hg, Сd, and REE, which flows into the Ur River (a tributary of the Inya). The stream transports gold and silver existing in dissolved + colloidal and particulate forms. Dissolved + colloidal gold and silver have similar distribution patterns with their contents inversely proportional to рН. Dissolved + colloidal gold in the AMD water is more abundant than silver (0.4–1.2 ppb Au against 0.1–0.3 ppb Ag). Gold changes from the dissolved + colloidal (in AMD) to particulate (till 0.03 ppb) forms and precipitates in progressively larger amounts with distance from the tailings. Silver in most of the analyzed natural and tailings-impacted waters exists as suspended particles (to 1 ppb). The concentrations of gold and silver are the highest (1.8–2.1 ppb Au and 4.5–5.7 ppb Ag) in peat pore waters within the geochemical trains of the tailings, apparently as a result of re-precipitation on organic barriers.

The Tomtor massif of Paleozoic ultramafic alkaline rocks and carbonatites is located in the northern part of the Sakha Republic (Yakutia). The massif (its total area is ~ 250 km2) is ~20 km in diameter, with a rounded shape and a concentrically zoned structure. The core of the massif consists of carbonatites surrounded by a discontinuous ring of ultramafic rocks and foidolites. The outer part is composed of alkali and nepheline syenites. All rocks are weathered and covered with eluvium, which is the thickest after carbonatites enriched in phosphates and REE. The weathering profile consists of four layers, from the top: kaolinite–crandallite, siderite, goethite, and francolite. The highest-grade ores are observed in the bedded deposit which fills depressions in “sagging” eluvium. The ores are laminated and cryptogranular, with high Nb, Y, Sc, and REE contents (on average, 4.5% Nb2O5, 7–10% REE2O3, 0.75% Y2O3, and 0.06% Sc2O3). The highest-grade ores are natural Nb and REE concentrates. The total REE content in some layers is > 10%. The morphologic features of the highest-grade phosphate ores from the northern part of the Burannyi site were studied. The ore-forming minerals belong to the pyrochlore group, crandallite group (goyazite), and monazite-Ce. The pyrochlore group minerals occur mainly as crystals that were completely replaced by barium–strontium pyrochlore and/or plumbopyrochlore but retained the original faces; also, they occur as numerous conchoidal fragments. The grains of the pyrochlore group minerals sometimes have a zonal structure, with an unaltered pyrochlore core and a reaction rim. Goyazite occurs predominantly as colloform grains. According to SEM and TEM data, monazite occurs in the ores as ~50 nm particles, which cover the outer part of halloysite tubes (800–3000 nm long and 300 nm in diameter) as a dense layer and make up peculiar biomorphic aggregates. The mineralogical data, the occurrence of biomorphic aggregates, and the close association of organic remains with ore minerals suggest that the high-grade ores of the Tomtor deposit, including the Burannyi site, resulted from a hydrothermal–sedimentary process with a presumably important role of bioaccumulation of REE phosphates.

This study used geological, geochemical, and microbiological data to examine the Uzon oils and conditions within the Uzon caldera. The trace-element compositions of crude oils and solutions from boreholes and hydrothermal springs were determined by ICP-MS. The majority of hydrothermal manifestations within the Uzon caldera are controlled by three trends of faults. The major fault zone, trending nearly E–W, is located between Kikhpinych and Taunshits volcanoes. It acts as a magma conduit and hosts numerous oval-shaped hydrothermal vents. The Oil site is situated on the periphery of the hottest area of highest hydrothermal activity within the Eastern thermal field. On the Eh–pH diagram, most solutions of the Uzon caldera define distinct fields and trends which correlate with the stability fields for sulfur and iron. The Oil site is characterized by very wide variations in temperature and Eh–pH parameters of pore solutions. The geochemical signatures of the solutions at this site are broadly similar to those from other areas of the Uzon caldera, but differ in their sulfide ion and sulfate ion concentrations. These differences can be explained by mixing of deep chloride-sodium hydrothermal solutions and solutions produced during surface oxidation of sulfide-containing material. With respect to the average continental crust, the Uzon oil is enriched in S, As, and Hg. The crude oil and solutions have broadly similar concentrations of B, S, Cl, As, Se, Br, Cd, I, Hg, and Pb and highly variable concentrations of Ti, V, Cr, Co, Ni, Cu, Cd, Nb, and Sn. The community structure of archaeal assemblages in springs and test pits at the Eastern thermal field was analyzed by 16S rRNA library and pyrosequencing methods. It was found that the proportion of archaea in the microbial communities of the Uzon caldera ranges from 2 to over 70% of the total sequences identified. Crenarchaeota were found in large proportions in all samples except one. The majority of the sequences in four samples were affiliated with Euryarchaeota, which comprise methanogenic archaea, extreme halophiles, and some extreme thermophiles. The results of geological, mineralogical-geochemical, microbiological and physicochemical studies of oil seeps in the Uzon caldera reveal distinctive geochemical characteristics of crude oil and the complexity of oil formation.

The distribution of chemical elements in bottom sediments of Fumarolnoe lake was obtained by XRFA. The mineral composition of the sediment was examined by SEM, XPA. Variations in contents of alkaline elements in the column of bottom sediments of the Fumarolnoe Lake have been studied using spectral methods (Wavelet and Fourier analyses). It has been established that concentrations of these elements change periodically, periods being correlated with periodic changes in seismic conditions of the present region

Mineral processing wastes may be considered as a natural experimental laboratory for study of mineral� ogical and geochemical peculiarities of rocks and ores changes, forms of elements transport and precipita� tion. Wastes often contain significant amounts of valu� able components including precious metals, which are mobilized into solution, are removed beyond tailing pit, and are reprecipitated on different geochemical barriers in the exogenic process. Carbonaceous mate� rial is one of the most effective geochemical barriers accumulating many elements. Coal [1] and black shale [2] are often considered. Peat and peat bog deposits may be active concentrators of different elements as well, but direct estimation of their role in accumula� tion of precious metals is practically nonexistent. This study is aimed at investigation of gold redistribution and its speciation in peat contacting with acid mine drainage solutions formed by interaction of surface waters with mineral processing wastes of the Ursk ore field in the example of the Ursk tailing pit (Kemerovo region, Russia). The Ursk tailing pit, constructed for more than 80 years ago, is composed by the cyaniding wastes of primary auriferous polymetallic, pyrite ores, and that of the oxidation zone of the New Ursk deposit forming two piles with a height of 10–12 m [3, 4]. The average Au content in primary ores reached 4 ppm. During the whole period of tailing pit existence, the unfixed mate� rial of wastes has been washed out by rainfalls and flood waters. The natural creek draining waste piles has been evolving into acid [4]. Wetland with peat bog located downstream of the tailing pit is burned by acid mine drainage solutions and is covered by the trans� ported wastes layer up to 50 cm through to the Ur River (Fig. 1). Remains of swampy tussocks rise above wastes surface. Based on granulometric differentiation of the transported wastes material, three areas were distinguished in a dispersion trains of the tailing pit

Numerous bitter lakes, largely closed and shallow, are concentrated in a small area of the South of Western Siberia (Kulunda and Barabinsk steppes). Most lakes are marked by the development of thick black or grayish blue silt organogenic sediments formed due to the dying-off of local halophilic organisms. Salt lakes are of great interest for scientists. The investigation was conducted in the context of complex biological and biochemical studies aimed at identifying regularities in the redistribution of elements between components of a salt-lake system by SR-XRF (Synchrotron Radiation X-ray Fluorescence).

Background Nothing is currently known about microbial composition of saline lakes of the Novosibirsk region and its dependence on physical-chemical parameters of waters. We studied the structure of microbial communities of saline lakes of the Novosibirsk region and the effect of physical-chemical parameters of waters on microbial communities of these lakes. Results According to the ion content, the lakes were classified either as chloride or chloride-sulfate types. Water salinity ranges from 4.3 to 290 g L−1. Many diverse microbial communities were found. Filamentous and colonial Cyanobacteria of the genera Scytonema, Aphanocapsa, and/or filamentous Algae dominated in littoral communities. Spatial and temporal organization of planktonic microbial communities and the quantities of Archaea and Bacteria were investigated using fluorescent in situ hybridization. We have found that the dominant planktonic component is represented by Archaea, or, less frequently, by Bacteria. Various phylogenetic groups (Bacteria, Archaea, Algae, and Cyanobacteria) are nonuniformly distributed. The principal component analysis was used to detect environmental factors that affect microorganism abundance. We found the principal components responsible for 71.1 % of the observed variation. It was demonstrated that two-block partial least squares was a better method than principal component analysis for analysis of the data. We observed general relationships between microbial abundance and water salinity. Conclusions We have performed the first-ever study of the structure of the microbial communities of eleven saline lakes in the Novosibirsk region along with their physical-chemical parameters of waters. Our study demonstrates that saline lakes in the Novosibirsk region contain a unique microbial communities that may become a prolific source of microorganisms for fundamental and applied studies in various fields of ecology, microbiology, geochemistry, and biotechnology, and deserve further metagenomic investigation.

The contents of many elements in a microbial community and various associations of a carbonate body from the Garga hot spring (Barguzin Valley, Baikal Rift Zone) were analyzed with a synchrotron X-ray fluorescence analysis. The coefficients of biological accumulation have been determined. The contents of practically all elements, except for Sr, in the microbial community are higher than in the carbonate body, and the Ge and Zn contents are higher by an 2 order of magnitude. The vertical cross section of the carbonate body contains three associations two of which formed as a result of microbial activity. The contents of elements in all associations are similar. The Ge content in the microbial community is 270 ppm, on average, whereas in the carbonate body it is less than 2 ppm. The elevated Ge contents could serve as a diagnostic indicator of the microbial community’s development around the sulfide-less alkaline hot springs in the presence of increased contents of radium isotopes. A sample of the carbonate body with layers formed as a result of the microbial community activity was continuously scanned with a step of 0.5 mm. No Ge-rich areas were determined, which indicates its removal by solutions during the destruction of organic matter.

The features of present deposits that form in the vicinity of hot springs can provide clues to the parameters of paleowaters in places of past hydrothermal activity marked by remnant carbonate and/or siliceous sinter. We investigated a large carbonate body at the Garga hot spring developing in the Baikal zone of nitric hydrotherms in the Barguzin Rift Zone valley. The main focus was on the structure of the carbonate mound, as well as on the partitioning of radioactive elements between the cyanobacterial mat and the inorganic component of the body (the issue that has never been explored before). The cyanobacterial community of the Garga spring is an active biosorbent of 226Ra, 228Ra, 210Pb. The radionuclides accumulated by biosorption become preserved in minerals that form within the bacterial community. The reported data of mineral formation in the cyanobacterial mat along with the mineralogy and structure of the carbonate mound of the Garga spring have implications for the complex history of the Garga body. It has been produced jointly by precipitation from the venting thermal water (opal-calcite-fluorite-barite-celestine assemblage) and microbial metabolic activity (coarse calcite and thin black encrustation rich in Mn minerals).

The waste is not fixed; during the entire period of the tailing’s existence it is regularly diluted by rainwa� ter and flood water. The ravine’s swampy territory below the tailings down to the Ur river (a confluent of the Inya river) is covered with the derived waste matter (Fig. 2); the area’s vegetation has been destroyed due to the acid mine drainage influence. The derived mat� ter lays over the peat, with swamp hassocks still present. Down in the ravine, in the valley of the river Ur, the waste covers the splinters of limestone.

The oldest lithified cyanobacteria found in sedi� ments date back to 3.6 Ga, and largescale formation of stromatolitic structures associated with copious cyanobacterial mats is known at 2 and 1 Ga (1, 2). Today's cyanobacteria have been expelled to extreme habitats, such as hot springs where thermophilic com� munities can live. Many hot springs vent in the Bar� gusin basin of the Baikal Rift Zone (3-5).They are alkaline waters with high silica concentrations and a nitrogendominated gas phase. The waterbearing rocks are sheared outsized granites or granodiorites. Microbial populations have been recognized at all venting sites (6) (more than ten within the Barguzin basin), but travertine occurs at three sites only (Alla, Garga, and Gusikha) (7).The thickest carbonate (trav� ertine) framework at the Garga spring has been attrib� uted to the microbial activity (8). Yet, minerals depos� ited immediately in the hotspring environments of the basin have never been described. We investigated microbial populations of five springs (Alla, Kuchiger, and Umkhei on the right side of the Barguzin valley, and Garga and Uro on its left side) and discovered bacteriamediated precipitation of amorphous silica and calcite in the Alla and Garga springs, just where travertine is formed. Our objective was to study the morphology of minerals and the laws of their forma� tion in microbial communities. Water samples collected in 2007 and 2008 from the emergent sources and down the stream were filtered through (0.45 µm) membrane filters. Eh and pH, as well as O2 and HS - concentrations, were measured at the site by an Anion 4100 meter and MERCK tests (Germany), respectively. The water chemistry was analyzed by several methods to provide cross valida� tion: atomemission spectrometry, ICPMS, capillary electrophoresis, and atomic absorption. For transpor� tation, the microbial mat samples were packed with caution to preserve their structure, and were split into layers and dried in the laboratory. The element abun� dances in the organic and mineral components of the mats were determined by SRXRF method. The com� munity composition of the mats, and the mineral mor� phology and phase composition were studied on "Carl Zeiss" light microscopes (Axiolab 40 Pol and Axio Imager, Germany) and on a Leo Oxford 1430VP scan� ning electron microscope (SEM) (Germany), analysts S.V. Letov and A.T. Titov. The predominant ions in the water of the Alla springs are bicarbonate, silica and sodium. The emer�

In article minerals formation and elements accumulation in microbial mats of some hot springs of the Barguzin basin (Baikal Rift Zone) is discussed. The content of a wide spectrum of elements in microbial mats is studied by means of the method SR-XRF. Regularity of elements accumulation by community depending on geochemical features of hot spring's waters are discussed. These elements are distributed in different ways between organic and mineral substance of the microbial mats. The distribution of K, Mn, Ni, Cu, Zn, Fe is regular, Ca, Rb, Sr are almost totally related with the mats mineral part, while Ga, Ge and Br are accumulated in mats organic substance. Germanium element is concentrated in considerable amounts in the cyanobacterial communities, that develop in sulphideless springs with a higher radon concentration.

Geochemical zoning of the high-sulfide (40–45 wt.% sulfides) and low-carbonate (3 wt.% dolomite) waste at the Berikul gold mine, Kemerovo region, Russia, was studied in order to understand the processes controlling As, Cd, Cu, Pb and Zn migration from the waste. The following zones were distinguished from bottom to top: (1) slightly altered waste, (2) cemented hardpan zone, (3) melanterite zone, (4) intermediate zone and (5) jarosite zone. A sequential scheme of extraction was used to separate (a) water-soluble, (b) exchangeable, (c) carbonate, (d) phases bound with Fe 3+ , and (e) residual fractions of Fe, As, Zn, Cu and Cd. The two basal zones reflect an early stage of weathering, where acid generated by sulfide oxidation is neutralized by carbonate. Neutralization processes promote coprecipitation of As, Cd, Cu, Pb and Zn in Fe 3+ phases, such as amorphous Fe sulfo-arsenate and jarosite. An intermediate stage, recorded in the melanterite and intermediate zones, is identified by the disappearance of the carbonates and a decrease in the pH of pore solutions. At low pH, sulfides are oxidized by Fe 3+ , producing Fe 2+ , SO 4 2− , and liberating As, Zn, Cu and Cd, which accumulate in the pore water. This step results in the precipitation of Zn-, Cu- and Cd-bearing melanterite. The intermediate stage of weathering continues until most of the sulfide fraction has been oxidized. Then, as shown in the upper jarosite zone, the concentration of Fe 3+ again increases in the pore waters because it is not being utilized in sulfide oxidation, and Fe 3+ phases, such as jarosite, precipitate. By this stage, significant amounts of As, Zn, Cu and Cd have been leached from the weathered residue, but Pb precipitates in the jarosite.

The recovery of gold from ores containing arsenopyrite releases significant amounts of arsenic into the environment. Arsenic releases primarily result from the processing and oxidation of stored mine tailings. This investigation examines: (1) the distribution of arsenic, iron, manganese and their chemical species in sediment cores extracted from a tailings impoundment in the Kemerovo region of southwestern Siberia; and (2) the weathering of arsenic minerals collected from its tailings dam. The data demonstrate that during storage of the sediments within the impoundment, arsenic is predominantly present as residual arsenopyrite and, to a lesser degree, as substances co-precipitated with iron hydroxide. The arsenic released from the sediment results from an oxidative dissolution of arsenopyrite and reductive dissolution of Fe oxides.