Deposits Of Siberia Research Articles

Distribution of indium in ores of some base metal and tin–sulfide deposits in Siberia and the Russian Far East

The study of base-metal massive sulfide and tin–sulfide deposits in Siberia and the Russian Far East has revealed that the indium content in ores exceeding the average statistical value at similar deposits worldwide could be economically important. Sphalerite and chalcopyrite and chalcopyrite, bornite, and sphalerite are the major indium carriers in the base-metal massive sulfide and tin–sulfide ores, respectively. In addition, base-metal massive sulfide ores have high Cd, Ag, and Te contents, whereas tin–sulfide ores have elevated Ge, Ga, and Nb contents. This has stimulated the investment attractiveness of these deposits.

On Late Jurassic–Early Cretaceous oysters of the genus Deltoideum Rollier (Bivalvia, Ostreoidea) from Siberia

Morphology, palaeoecology, and phylogeny of oysters of the genus Deltoideum Rollier from the Upper Jurassic and Lower Cretaceous deposits of Siberia are discussed. The diagnosis and composition of the genus are revised. A new endemic subgenus, Boreiodeltoideum subgen. nov., of the genus Deltoideum is described. This subgenus includes two species, D. (B.) praeanabarensis (Zakharov) and D. (B.) anabarensis (Bodylevsky).

RUSSIAN–JAPANESE TRADE AND ECONOMIC RELATIONS: IS THERE A NEW FULCRUM?

Against the background of political chilling between Russia and Japan trade and economic cooperation objectively form a basis for a positive development of bilateral relations in the foreseeable future. The structure of mutual trade has not changed significantly for a number of years. Russia plays the role as a pivotal supplier of certain raw materials for the Japanese market, namely energy resources, non-ferrous metals, seafood and timber. From Japan Russia imports mainly passenger cars and a certain amount of industrial equipment. With regard to investment relations between Russia and Japan, there exists a serious structural problem - the two economies are interdependent from the point of view of the technological division of labor. Russia, particularly its Eastern regions, not possessing sufficient infrastructure and logistics capabilities, as well as cheap labor resources, does not have any competitive advantages for Japanese investment compared to other countries like China. The potential of Russia is mostly viewed in Japan just as an energy donor. Thus the largest prospects of investment cooperation lie in the energy sphere. One can talk of the possibility for raising Russia's share in the Japanese oil and LNG markets. This perspective is supported by the instability of the political situation in the Middle East, which is Japan's main partner for energy supplies. In this connection, large-scale investment projects in the energy field, like the construction of gas pipeline "Sakhalin - Japan" or a power bridge "Sakhalin - Hokkaido", retain their perceptiveness. However, given the political, juridical, organizational, technical and other problems, these projects are difficult for implementation at the present stage. In this situation, the allocation of a certain share for Japan in the strategic energy deposits of Siberia and the Far East and the admission of Japanese capital to the exploration and development of these deposits seem to be a realistic choice for Russian strategic planning towards Japan, as such a cooperation would not be a subject of Western sanctions against Russia. For Russia it is important to build with Japan relationship on a more long-term and lasting basis. One of the possible ways here is to conclude a bilateral economic partnership agreement.

Modes of occurrence of scandium in coals and peats (A review)

The modes of occurrence of scandium in peat and coal from different deposits in Siberia, Russian Far East, Kazakhstan, and Mongolia was studied with the use of a set of methods. The fractions of coal with different densities and the group components of peat and brown coal were considered. The selective leaching of Sc from brown coal and black coal with ammonium acetate and concentrated acids was performed, and a correlation between the Sc content and the ash content was studied. It was established that, at the early stages of a coal-formation process, the bulk of scandium in low- and medium-ash peats and brown coal was bound to organic matter. Humic substances (fulvic acids + humic acids) are the main carriers and concentrators of scandium. In all cases, the scandium content of humic acids was higher than the average concentration in peat and brown coal. A decrease in the yield of humic acid fractions in the coalification process decreases their fraction in the total balance of scandium; however, the fraction of insoluble humic substances increases in this case. The modes of occurrence of scandium changes in the course of coalification. In low-rank black coal (grade D), a considerable fraction of scandium occurs in the organic matter. The mineral forms of scandium predominate in mature black coal. Scandium is a constituent of silicates, aluminosilicates, phosphates, and aluminophosphates; it likely forms its own mineral species.

Gibbsite and kaolinite in the biological pedoturbation zone of the lateritic profile: A different fate (exemplified by deposits of Siberia, India, Guinea, and Brazil)

Gibbsite and kaolinite in the biological pedoturbation zone of the lateritic profile: A different fate (exemplified by deposits of Siberia, India, Guinea, and Brazil)

Atmospheric Ozone and Methane in a Changing Climate

Ozone and methane are chemically active climate-forcing agents affected by climate–chemistry interactions in the atmosphere. Key chemical reactions and processes affecting ozone and methane are presented. It is shown that climate-chemistry interactions have a significant impact on the two compounds. Ozone, which is a secondary compound in the atmosphere, produced and broken down mainly in the troposphere and stratosphre through chemical reactions involving atomic oxygen (O), NOx compounds (NO, NO2), CO, hydrogen radicals (OH, HO2), volatile organic compounds (VOC) and chlorine (Cl, ClO) and bromine (Br, BrO). Ozone is broken down through changes in the atmospheric distribution of the afore mentioned compounds. Methane is a primary compound emitted from different sources (wetlands, rice production, livestock, mining, oil and gas production and landfills).Methane is broken down by the hydroxyl radical (OH). OH is significantly affected by methane emissions, defined by the feedback factor, currently estimated to be in the range 1.3 to 1.5, and increasing with increasing methane emission. Ozone and methane changes are affected by NOx emissions. While ozone in general increase with increases in NOx emission, methane is reduced, due to increases in OH. Several processes where current and future changes have implications for climate-chemistry interactions are identified. It is also shown that climatic changes through dynamic processes could have significant impact on the atmospheric chemical distribution of ozone and methane, as we can see through the impact of Quasi Biennial Oscillation (QBO). Modeling studies indicate that increases in ozone could be more pronounced toward the end of this century. Thawing permafrost could lead to important positive feedbacks in the climate system. Large amounts of organic material are stored in the upper layers of the permafrost in the yedoma deposits in Siberia, where 2 to 5% of the deposits could be organic material. During thawing of permafrost, parts of the organic material that is deposited could be converted to methane. Furthermore, methane stored in deposits under shallow waters in the Arctic have the potential to be released in a future warmer climate with enhanced climate impact on methane, ozone and stratospheric water vapor. Studies performed by several groups show that the transport sectors have the potential for significant impacts on climate-chemistry interactions. There are large uncertainties connected to ozone and methane changes from the transport sector, and to methane release and climate impact during permafrost thawing.

Mantle plumes of Central Asia (Northeast Asia) and their role in forming endogenous deposits

The Phanerozoic within-plate magmatism and the related deposits of Siberia are reviewed. The formation of post-perovskite at about 2.5 Ga in the Earth’s interior and the isotope characteristics of within-plate igneous rocks have shown that plate tectonics and deep geodynamics started to operate at about 2–2.5 Ga. The assembly and breakup of supercontinents under the effect of the superplumes formed in layer D″ is considered. Thus, the supercontinent–superplume cycles spanning about 700 Ma are recognized in the Earth’s history.The manifestations of the within-plate magmatic activity are found throughout the whole Phanerozoic. It was demonstrated earlier that between 570 and 160 Ma, the Siberian continent drifted within the African hot mantle field or large low shear velocity province (LLSVP). At least four plumes, excluding the superplume leading to the breakup of Rodinia at 750 Ma, interacted with the Siberian continent. The superplume leading to the breakup of Rodinia was also responsible for the origin of ultramafic intrusions with carbonatites hosting rare-metal (Nb, Ta, REE) mineralization as well as ultramafic–mafic intrusions with Cu–Ni–Pt mineralization localized along the rift zones.The plumes originated in other Phanerozoic cycles formed most likely at the lower-upper mantle boundary, where most of the stagnant slabs is accumulated. Those plumes were responsible for the origin of within-plate igneous rocks. The granitic batholiths formed in the centers of zonal area surrounded by rift zones containing abundant rare-metal intrusions with rare-metal mineralization. Gold, tin, base metal, and porphyry copper deposits are also related to these zonal area.The studies have shown that the formation of folded zones and related deposits which surround these zones as well as the structures of cratons and their metallogenic specialization should be considered in terms of both plate tectonics and plume tectonics.

ECONOMIC EVALUATION OF GOLD-ORE DUMP REPROCESSING EFFICIENCY

An economic projection is presented in the paper on the heap leaching technology for extracting a residual gold from the gold-ore dumps accumulated at the exploited or closed gold mines. A brief analysis is performed on the legal status of use this source of raw materials, availability and efficiency of the heap leaching method are reviewed, and the potential users of this method are assessed. An investment plan is created for involving anthropogenic dumps of gold-raw materials at one of the ore deposits in Siberia (heap complex of the North-Western flank of the Sovetskoye minefield, Krasnoyarsk region, North-Yenisey area).

General characteristics of the geochemical evolution of silicic melts during the development of massive sulfide magmatic ore systems: Evidence from the investigation of melt inclusions

The investigation of melt inclusions in the minerals of volcanic rocks from the massive sulfide deposits of Siberia and the Urals revealed some specific features in the development of their magmatic ore systems. It was shown that the petrochemical and rare earth element compositions of melt inclusions reflect the geodynamic conditions of their formation: island arc conditions for the massive sulfide deposits of Rudny Altai, eastern Tuva, and the Salair Range and a back arc basin environment for the Yaman-Kasy deposit. The silicic melts of inclusions from the volcanic rocks of massive sulfide deposits show some specific features with respect to the contents of volatile components. In all of the ore deposits studied, fluorine content was always low (0.03–0.08 wt %), whereas chlorine content (0.13–0.28 wt %) was higher than the average value for silicic melts (0.17 wt %). There is a strong differentiation of water content in melt inclusions, both between deposits and between various volcanics from a single deposit. Ore-bearing melts show the highest water contents of 3.34–4.07 wt %. High Cu contents in the silicic melts of the Yubileinoe and Kyzyl-Tashtyg deposits (up to 7118 and 3228 ppm, respectively) may indicate the affinity of some ore components to particular silicic magmas. This is supported by the elevated contents of Cu in the porphyry Cu deposits of Romania (Valea Morii), Mongolia (Bayan Ula), and Bolivia. On the other hand, the silicic melts of inclusions from the molybdenum-uranium deposit of the Strel’tsovka ore field show high contents of another group of ore components (U and F).

Desulfosporosinus hippei sp. nov., a mesophilic sulfate-reducing bacterium isolated from permafrost

The sulfate-reducing strain 343T was isolated from ancient permafrost deposits in Siberia, Russia. Based on 16S rRNA gene sequence analyses, this strain was closely related to Desulfosporosinus species, showing 97.9 % 16S rRNA gene sequence similarity to Desulfosporosinus meridiei DSM 13257T, 97.6 % similarity to Desulfosporosinus auripigmenti DSM 13351T, 97.2 % similarity to Desulfosporosinus lacus DSM 15449T and 96.2 % similarity to Desulfosporosinus orientis DSM 765T. The strain was found to contain b-type cytochromes and to reduce only sulfate and thiosulfate using lactate as an electron donor but not sulfite, elemental sulfur, fumarate, nitrate or Fe(III). These data, considered in conjunction with DNA-DNA hybridization data, cell-wall chemotaxonomy and data on physiology, support recognition of strain 343T as representing a distinct and novel species within the genus Desulfosporosinus, namely Desulfosporosinus hippei sp. nov., with the type strain 343T (=DSM 8344T =VKM B-2003T).

Corrosion fracture of equipment within wells and pipelines at western Siberia oil deposits

It is shown that corrosion fracture of equipment within wells at the Western Siberia deposits occurs due to specific forms of corrosion, in particular hydrogen sulfide corrosion fracture (HCF) that is caused by the presence of hydrogen sulfide in aqueous solutions. HCF is connected with metal embrittlement by hydrogen that is a product of reaction with hydrogen sulfide.

Low-Temperature Synthesis of the Cordierite Phase in Ceramic Mixtures of Natural Raw Materials

The synthesis of cordierite in mixtures of magnesia and clay raw materials recovered from deposits in Siberia is studied experimentally. For reference, a mixture based on clay from the Veselovskoe deposit (Ukraine) is used. To promote the synthesis, raw materials are mechanically activated using a vibratory centrifugal mill. The synthesis can be brought to completion at lower temperatures under mechanical activation conditions using a cordierite addition. Production of synthetic cordierite and cordierite products (blocks of catalyst carries with a cellular structure) organized on a pilot-plant basis at the G. K. Boreskov Institute of Catalysis is reported.

Low-Temperature Synthesis of Cordierite Using Naturally Occurring Ceceramic Materials

The synthesis of cordierite in mixtures composed of argillaceous and magnesian raw materials from a number of deposits in Siberia (Tomsk, Novosibirsk, Irkutsk, and Kemerovo Districts) is studied experimentally. Mixtures based on the clay from the Veselovskoe deposit (Ukraine) are used as a reference. A VMTs-25-1 centrifugal vibromill was used for activating the precursor materials. Two factors simultaneously applied — mechanochemical activation and structure-forming additions — provide conditions for lowering the temperature and increasing the degree of synthesis. A technique for synthesis of cordierite with the simultaneous sintering of components (blocks of catalyst carriers with cellular structure) at 1200°C has been developed at the G. K. Boreskov Institute of Catalysis.

To the study of Early Mesozoic, Palaeozoic, and Precambrian nannofossils

Samples of carbonate rocks from Triassic deposits of Siberia and the Northern Caucasus, Carbon and Devonian deposits from the East European platform, and Proterozoic (Precambrian) deposits from Karelia have been studied by means of electron microscopy. Evident coccolites were retrieved from the Triassic deposits, whereas the structures very similar to those of re-crystallized Cenozoic limestones containing nannofossils have been discovered in Palaeozoic and Proterozoic deposits.

Gas Hydrates of Siberia

Abstract: Natural gas hydrates were first observed on 21 July 1961 (the discovery was officially registered on 24 December 1969).1 It soon became clear that these compounds are not just chemical curiosities, or a nuisance for gas transportation in pipe lines, but rather that they are related significant natural phenomena. It is possible that in the past natural gas hydrates have manifested themselves in marine and land incidents. In future gas hydrates may offer an inexhaustible source of energy and chemical raw material. However, if not accessed with sufficient knowledge, gas hydrates may be destabilized to create many local problems and possibly global problems as well. In the USSR and more recently in Russia, a number of groups are traditionally involved in investigation of different aspects of gas hydrates problems. These groups have made significant contributions to present knowledge about the nature and properties of the gas hydrates. The Siberian branch of the Russian Academy of Sciences recently started an interdisciplinary program to comprehensively investigate all major aspects of gas hydrates, with special emphasis on natural gas hydrates and gas hydrates deposits in Siberia and its adjacent regions. The program consists of three components: (1) Geology of gas hydrates in the cryolito‐zone of Siberia and in the bottom deposits of the Arctic and East seas, and of Lake Baikal. (2) Physicochemical study of hydrates of different gases. (3) Ecological monitoring. In this paper we offer a short summary of the main results of these three components of the program. We emphasize the second component, since it is close to the scientific interests of the author.

A multidisciplinary study of invisible gold in arsenopyrite from four mesothermal gold deposits in Siberia, Russian Federation

Characterization of gold in four Siberian mesothermal gold deposits was done through a multidisciplinary investigation (including ore microscopy, INAA, SIMS, EPMA, and 197 Au Moessbauer spectroscopy). The deposits are Olympiada and Veduga in the Enisei Mountain Range and Nezhdaninskoye and Sentachan in the Verkhoyansk-Kolyma area, in which vein and disseminated orebodies are hosted by sedimentary sequences metamorphosed to amphibolite (Olympiada) and greenschist facies. Ore minerals include arsenopyrite and pyrrhotite (or pyrite) as major constituents with minor scheelite, and sphalerite, chalcopyrite and native gold as minor constituents (with + or - aurostibite, galena, gudmundite, tetrahedrite, stibnite, and berthierite). Some of the gold mineralization is metallurgically refractory in all four deposits, largely due to the presence of invisible gold in arsenopyrite, and to a lesser extent, in pyrite. Several generations of arsenopyrite are recognized in the auriferous zones of the Veduga, Nezhdaninskoye, and Sentachan deposits. Textural observations indicate late deposition of native gold with respect to arsenopyrite. No evidence was found of arsenopyrite recrystallization and the crystallization of native gold is considered to result from an evolution of fluids rather than redeposition of gold.Wide variations in the gold contents of arsenopyrite occur within deposits, within samples, and within individual grains. INNA analyses of individual arsenopyrite grains (30-70 mu m in size) show that the gold concentration ranges from 197 Au Moessbauer spectra of arsenopyrite concentrates from the Veduga, Nezhdaninskoye, and Sentachan deposits exhibit mainly a component with isomer shifts between 3.3 and 3.6 mm/s which is interpreted as strong evidence of the presence of chemically bound gold in the arsenopyrite crystal structure. The spectra of samples from the Veduga deposit also contain minor amounts of native gold, for which negative isomer shifts near -1.2 mm/s are expected. Metallic gold dominates in the 197 Au Moessbauer spectra of samples from the Olympiada deposit, but varying amounts of chemically bound gold are also visible in the spectra, some attributed to aurostibite.It is concluded that the ores from these deposits are refractory, partly because the gold occurs in arsenopyrite as chemically bound gold as well as submicroscopic metallic particles probably as small as 2 nm. This study also shows that Au-bearing arsenopyrite is usually depleted in As with respect to its stoichiometric composition, but correlation of Au enrichment to Fe deficiency was not found. It is inferred from 197 Au Moessbauer spectroscopy that substitution of Fe (super 3+) for Au (super 3+) is most likely. The temporal change in different modes of gold occurrence (i.e., as native gold or invisibly in sulfides) in the mineralized zones and veins is interpreted to result from an evolution of fluids rather than to be a recrystallization phenomenon. Dissemination of Au-bearing sulfides within the altered halos infers that a pervasive fluid-rock interaction was an effective mechanism for deposition of minerals and gold. Absorption of gold complexes onto sulfide surfaces is also suggested to have played an important role in the deposition of native gold during the latest episodes in the formation of the deposits.

Nature and Composition of the Devonian Coals of Russia

The first economic coal accumulation in the territory of Russia is associated with the Devonian deposits of Siberia. In the Barzas area of the Kuznetsk basin a 0.8-3.6 m thick coal seam occurs in Jivetian. The Middle Devonian coals are also recorded in the Urals and in Kazakhstan. They have a peculiar microstructure and contain a great amount of thick psilophytic culticle (to 60%). The Barzas coals are subbituminous and contain a lot of volatile matter and resins. The Upper Devonian coals differ in their composition and original matter from the Middle Devonian ones and are similar to the Lower Carboniferous coals in the European part of Russia. The occurrence areas of the Upper Devonian coals have a submeridional orientation (from the Russian Platform through Timan toward islands in the Arctic Ocean)

Pre-Ediacaran multicellular life: harbinger of a Phanerozoic radiation

Multicellular organisms must have had a substantial pre-Ediacaran history, but the fossil evidence is sparse and often equivocal. The taxonomic resolution necessary to constrain phylogenetic hypotheses is limited largely to Lagerstätte-grade fossils that retain evidence of diagnostic cell division patterns. Uniseriate and multiseriate filaments in the 1267-723 Ma Hunting Formation, Somerset Island, derive from transverse and longitudinal intercalary cell division programs indistinguishable from those of the modern red alga Bangia, and establish a significantly pre-Ediacaran datum point for the Rhodophyta. Likewise, on the basis of a distinctive “segregative cell division”, three taxa of siphonocladalean green algae (Chlorophyta) are identified in the ca. 750 Ma Svanbergfjellet Formation, Spitsbergen. Process-bearing vesicles in the Svanbergfjellet sequence further compare with the germinating zoospores of the modern chromophyte alga Vaucheria, while convincing Vaucheria-like thalli are reported from ca. 900 Ma deposits in Siberia. The broad co-occurrence of multicellular Rhodophyta, Chlorophyta, and Chromophyta by at least 750 Ma ago accords well with molecular evidence that suggests the three principal algal clades diverged from a common ancestor during a brief but marked radiation relatively late in eukaryote evolution.Complex multicellularity featuring cellular and tissue(?) differentiation is also encountered in the pre-Ediacaran fossil record. A large ornate form in the Svanbergfjellet succession preserves at least six readily distinguishable cell types and, despite its taxonomic uncertainty, can be characterized as at least as complex as the most complex modern algae or fungi. No cellularity is preserved in the late Proterozoic macrofossil Tawuia; however, SEM and light microscopy of its isolated wall reveal a complex histology suggestive of a relatively advanced grade of multicellularity. Another Svanbergfjellet macrofossil has a distinct wall structure and bears a terminal pair of large reniform structures; if these prove to be truly bilaterally symmetrical, this fossil represents a grade of organization otherwise not recognized until the Ediacaran. Further analysis of these and other pre-Ediacaran ‘problematica’ may clarify their taxonomic relationships and promises to resolve at least some of the ‘Cambrian explosion’ into a meaningful sequence of evolutionary change.

THE CLASSIFICATION OF PHYSICO‐GEOLOGICAL MODELS OF MINERAL DEPOSITS*

AbstractWe describe the concept of physico‐geological models (PGMs) in geophysical exploration. They represent a “general model”, a spatial combination of a set of particular models (disturbing bodies). The modeling is called complete, incomplete or approximate, depending on the degree of characterization of the PGM by parameters such as dimension, shape and petrophysical property. Each of the three modeling types can be realized as a conceptual, and analytical, or a material PGM. Both deterministic and stochastic PGMs exist; deterministic models are mainly used to investigate the possibilities of a geophysical method, while stochastic models serve to substantiate complex geophysical interpretations.Depending on the geological problem, PGMs are subdivided into multi‐alternative models (geological mapping, prediction, general prospecting) and double alternative models (specialized prospecting).An exploration‐oriented classification of the PGMs of mineral deposits is discussed. According to this classification the variety of known genetic deposit types is reduced to a limited number of generalized PGM types. The development of typical PGMs is illustrated with examples of magnetitic deposits of Siberia.

Senonian (late Cretaceous) palynofloral provinces in circumpolar areas of the northern hemisphere

The restricted geographical distribution of some spore and pollen taxa from Upper Cretaceous deposits in Siberia and the Far East has been used previously to distinguish boundaries of Senonian palynofloral provinces. The occurrence of Azonia recta in Yakutiya generally corresponds to the extension of the Khatanga-Lena Province into sub-polar areas. The Yenisey-Amur Province, characterized by the presence of Orbiculapollis, probably occupied the same temperate latitudes in Siberia as were occupied by the northwestern part of North America including Alaska and the islands of Arctic Canada. The Ural-West-Siberia Belt of mixed palynofloral composition extended from southern West Siberia northwards via Spitsbergen to the interior of North America, and separated the Yenisey-Amur Province from the Normapolles Province of eastern North America and Europe. The Senonian palynofloral differentiation of the U.S.S.R. and the distribution of Senonian palynofloral provinces in the whole of the Northern Hemisphere are illustrated herein.