In the composition of tantalum-niobates, the tin-bearing wodginite group minerals (WGM) were found: wod-ginite, titanowodginite, ferrowodginite, ferrotitanowodginite, lithiowodginite, tantalowodginite, “wolframowodginite”. We reviewed the worldwide research on WGM and created a database of 698 analyses from 55 sources including the author's data. WGM are associated with Li-F pegmatites and Li-F granites. Wodginite is the most prevalent mineral, occurring in 86.6 % of pegmatites and 78.3 % of granites. The occurrence of WGM in granites and pegmatites differs. For instance, titanowodginite and “wolframowodginite” occur three times more frequently in granites than in pegmatites, whereas lithiowodginite and tantalowodginite do not appear in granites at all. The difference between WGM in granites and pegmatites is in finer grain size, higher content of Sn, Nb, Ti, W, and Sc; lower content of Fe 3+ , Ta, Zr, Hf; higher ratio of Mn/(Mn + Fe); and lower ratio of Zr/Hf. The evolutionary series of WGM in pegmatites are as follows: ferrowodginite → ferrotitanowodginite → titanowodginite → “wolframowodginite” → wodginite → tantalowodginite; in granites: ferrowodginite → ferrotitanowodginite → “wolframowodginite” → wodginite → titanowodginite. WGM can serve as indicators of tantalum-bearing pegmatites and granites. In Russia the promising sources of tantalum are deposits of the Far Eastern belt of Li-F granites containing wodginite.
The evolution and ore content of granitoid magmatism in the Far East belt of lithium-fluoric granites lying in the Russian sector of the Pacific ore belt have been studied. Correlation of intrusive series in the Novosibirsk-Chukotka, Yana-Kolyma and Sikhote-Alin granitoid provinces of the studied region allowed to establish the unity of composition, evolution, and ore content of the Late Mesozoic granitoid magmatism. On this basis, a model of the type potentially ore-bearing intrusive series of the Far East belt of lithium-fluoric granites has been developed: complexes of diorite-granodiorite and granite formations → complexes of monzonite-syenite and granite-granosyenite formations → complexes of leucogranite and alaskite formations → complexes of rare-metal lithium-fluoric granite formation. The main petrological trend in granitoid evolution is increasing silicic acidity, alkalinity, and rare-metal-tin specialization along with decreasing size and number of intrusions. At the end of the intrusive series, small complexes of rare-metal lithium-fluoric granites form. The main metallogenic trend in granitoid evolution is an increasing ore-generating potential of intrusive complexes with their growing differentiation. Ore-bearing rare-metal-granite magmatism of the Russian Far East developed in the Late Cretaceous and determined the formation of large tungsten-tin deposits with associated rare metals: Ta, Nb, Li, Cs, Rb, In in areas with completed intrusive series. Incompleteness of granitoid series of the Pacific ore belt should be considered as a potential sign of blind rare-metal-tin mineralization. The Far East belt of lithium-fluoric granites extends to the Chinese and Alaskan sectors of the Pacific belt, which allows the model of the type ore-bearing intrusive series to be used in the territories adjacent to Russia.
We have investigated tectonic and magmatic factors of Li-F granites localization of the East of Russia. The study is based on the ideas of Far Eastern geologists about the deep structures of intraplate activity. A model of a source structure with mantle heat sources and ore-forming magmatic complexes was used. We carried out a special metallogenic analysis of the East of Russia as applied to the rare metal-tin-bearing formation of subalkaline leucogranites, including Li-F ones. Source structures are the main factor in the tectonic and magmatic development of the East of Russia, localization of ore-forming granites and the formation of rare-metal-tin ore regions. On deep layers of source structures there are areas of the mantle and earth's crust decompaction, heat, magmas and fluids sources, as well as granitoid cryptobatholiths. Relatively large massifs of leucogranites, small intrusions of tin monzonitoids and Li-F granites are concentrated near the modern surface. The source structures correspond to the rank of the ore region. The source structures in the South of the region are: Badzhalskaya, Miao-Chanskaya, Ippato-Merekskaya, Hogdu-Lianchlinskaya, Arminskaya, etc.; in the North: Pevekskaya, Kuiviveem-Pyrkakayskaya, Kuekvun-Ekiatapskaya, Iultinskaya, Telekayskaya, Central Polousnaya, Omsukchanskaya, etc. Three types of ore regions have been identified according to the degree of source structures and Li-F granites erosion. We have also outlined the patterns of source structures evolution and their place in the geological history of ore-bearing granites. A classification of source structures and its comparison with the classifications of regional intrusives and metallogenic subdivisions are proposed. It has been established that, despite the diversity of tectonic, geological and petrological settings in the East of Russia, the intrusions of Li-F granites are regulated by the same tectonic and magmatic factors. The tectonic and magmatic factors of Li-F granites localization in the East of Russia are identified and classified as geophysical, orogenic, geoblock, magmatic, metasomatic and disjunctive.
We investigated the deep structure of the lithosphere and the geodynamic conditions of granitoid magmatism in the Eastern Russia within the borders of the Far Eastern Federal District. The relevance of the work is determined by the need to establish the geotectonic and geodynamic conditions of the granitoids petrogenesis and ore genesis in the Russian sector of the Pacific Ore Belt. The purpose of the article is to study the deep structure of the lithosphere and determine the geodynamic conditions of granitoid magmatism in the East of Russia. The author's data on the magmatism of ore regions, regional granitoids correlations, archive and published State Geological Map data, survey mapping, deep seismic sounding of the earth's crust, gravimetric survey, geothermal exploration, and other geophysical data obtained along geotraverses. The magma-controlling concentric geostructures of the region are distinguished and their deep structure is studied. The connection of plume magmatism with deep structures is traced. The chain of concentric geostructures of Eastern Russia controls the trans-regional zone of leucocratization of the earth's crust with a width of more than 1000 km, which includes the Far Eastern zone of Li-F granites. Magmacontrolling concentric geostructures are concentrated in three granitoid provinces: Novosibirsk-Chukotka, Yano-Kolyma, and Sikhote-Alin. The driving force of geodynamic processes and granitoid magmatism was mantle heat fluxes in the reduced zones of the lithospheric slab. The distribution of slab windows along the Pacific mobile belt's strike determines the location of concentric geostructures and the magnitude of granitoid magmatism in the regional provinces. Mantle diapirs are the cores of granitoid ore-magmatic systems. The location of the most important ore regions of the Eastern Russia in concentric geostructures surrounded by annuli of negative gravity anomalies is the most important regional metallogenic pattern reflecting the correlation between ore content and deep structure of the earth's crust.
The aim of this paper was to establish the causes of the heterogeneity of the chemical composition of the metal obtained by the LC technology. The powdered raw material was made from a monolithic alloy, which was fused by the SLM, the initial raw material was a laboratory melting metal of a low-carbon chromium-manganese-nickel composition based on iron. To determine the distribution pattern of alloying chemical elements in the resulting powder, electron-microscopic images of thin sections were combined with X-ray analysis data on the cross-sections of the powder particles. As a result, it was found that transition (Mn, Ni) and heavy (Mo) metals are uniformly distributed over the powder particle cross-sections, and the mass fraction of silicon (Si) is uneven: in the center of the particles, it is several times larger in some cases. The revealed feature in the distribution of silicon is supposedly due to the formation of various forms of SiO 4 upon the cooling of the formed particles. The internal structure of the manufactured powder is represented by the martensitic structure of stack morphology. After laser fusion, etched thin sections revealed traces of segregation heterogeneity in the form of a grid with cells of ~ 200 μm.
The research focused on the composition of tourmaline from tin ore deposits and ore occurrences within the Verkhneurmiysky ore cluster in the Amur region. The aim of the study is to determine the indicative signs of tourmaline from cassiterite-quartz and cassiterite-silicate formations. This research is based on the materials of a long-term study of the mineralogy of the Far East deposits, conducted at the Mining University under the scientific supervision of Professor Yu.B.Marin. The relevance of the study involves predicting of tin and associated mineralization. For the first time, SIMS and Mössbauer spectroscopy were used to study tourmaline from this region. We identified the typomorphic characteristics of the tourmaline composition, which are proposed to be used as indicators of tin-ore deposits. Typomorphic characteristics of tourmaline from cassiterite-quartz formation: schorl (Mg/(Mg + Fe) = 0.06) with a high content of Al and K; Fe 3+ /(Fe 3+ + Fe 2+ ) = 0.03; Z Fe 3+ = 1 %; impurities: Nb, LREE (La, Ce, Pr), Be, Bi, F, Li, and Mn; LREE content > 9 ppm; positive Gd anomaly. Typomorphic characteristics of tourmaline from cassiterite-silicate formation: schorl-dravite (Mg/(Mg + Fe) = 0.22) with a high Ca content; Fe 3+ / (Fe 3+ + Fe 2+ ) = 0.17; Z Fe 3+ = 9 %; impurities: Zr, Y, Cr, V, Sn, In, Pb, W, Mo, Ti, HREE, Eu, Sr, Sb, and Sc; the content of Y is > 2 ppm, of HREE is > 3 ppm, Eu is > 0.1 ppm. The formation conditions of the cassiterite-silicate ore mineralization were more oxidizing than those of the cassiterite-quartz one. Tourmaline, formed under oxidizing conditions, contains such impurities as Sn, In, Nb, Bi, Sc, and LREE. The content of Sn isomorphic impurity in tourmaline reaches 8000 ppm.
This article is dedicated to the rare metal mineralization of stanniferous metasomatites of the Verkhneurmiysky ore cluster in the Far East of Russia. The mineral composition of metasomatites, formed during the five stages of the zwitter-tourmalineite stanniferous complex formation was studied. These stages were characterized as biotite-sericite, muscovite-quartz, siderophyllite-topaz, quartz-tourmaline, and chlorite-sericite. Rare metal-bearing minerals were selected and the concentrations of rare metals were estimated. The ore and geochemical types of the studied metasomatites were determined. There was shown the presence of many rare metal-bearing minerals in the composition of stanniferous metasomatites in this region. The set of the rare metals (Nb, Ta, W, Y, REE (from La to Lu), Be, Li, Zr, Hf, In, Sc, Se, and Cd) is of strategic importance for the development of the Russia mineral resources base. Minerals concentrating rare metals were divided into two types: minerals, containing rare metals due to its stoichiometry and minerals (if vein and ore origin) with isomorphic impurities of rare metals. There was traced the sequence of rare metal-bearing minerals formation and the evolution of their composition. Minerals of rare metals were formed throughout the history of the zwitter-tourmalineite formation, starting from the pre-ore stage of biotite feldspatholites to the post-ore of chloritites stage, including the zwitter ore stage. It was also shown a stepwise decrease in the intensity rare metal-bearing minerals formation and the evolution of the mineralization composition from lithophilic rare metals to chalcophylic ones: (LREE, Zr, Hf) → (W, Nb, Ta, Y, HREE, Sc) → (Sn, In, Cd, Se). Magmatic, metasomatic and crystal chemical factors affecting the rare metal-bearing minerals formation in the Verkhneurmiysky ore cluster have been revealed. The ore cluster's prospects are related to the presence of lithium- fluoric granites of the Pravourmiyskiy complex, controlling the tungsten-stanniferous zwitter and tourmalinite with associated rare metal mineralization.
It has been attempted to expand existing understanding of accessory mineralization evolution of rare metal-granite series at post-magmatic stage of their development and formation of associated hydrothermal deposits. Composition and distribution of rare elements of Verkhneurmiysk ore cluster have been examined from the position of mineralogy: the study focused on accessory and ore minerals Sn, W, Nb, Ta, Bi, Y, rare earth elements in rare metal Li-F granites and associated metasomatites. It has been discovered that accessory magmatic and hydrothermal mineral complexes share the same geochemical features, are formed under the leading role of abovementioned elements and consistently follow each other over time. It has been traced how mineral forms of accumulation of Sn, W, Nb, Ta, Y and rare earth elements evolve in the processes of magmatic crystallization and post-magmatic metasomatism in the time series: rare metal granites → zwitters → tourmalinites → chloritites. Mineral rocks of each stage were noted to inherit mineralogical and geochemical distinctions from the rocks of the previous stage. A significant number of minerals, forming in the course of two-three stages, have been discovered, as well as omnipresent magmagene-hydrothermal minerals. For a number of accessory minerals of rare metal granites post-magmatic generations have been identified. Special diversity among accessories of rare metal granites and zwitters was observed in tungsten, tin and bismuth minerals. Composition of Verkhneurmiysk ore cluster mineralization is in many aspects similar to the one of metasomatic accessory minerals of rare metal granites. Tungsten-tin deposits of Verkhneurmiysk ore cluster are polyformational and combine mineralogical features of cassiterite-quartz and cassiterite-silicate formations. Evolution of mineral forms of the key rare elements (Sn, W, Bi, Nb, Ta, rare earth elements) points to a genetic link between tungsten-tin mineralization of zwitter-tourmalinite formation and rare metal Li-F granites of the region. The evidence of that is a specific genetic category of accessory materials, formed as a result of pseudomorphism of protominerals, – transformational minerals or metasomatic accessory minerals. The list of metasomatic accessories includes exactly those minerals which are considered indicators of ore generation capacity of Far Eastern leucogranites: cassiterite, wolframite, scheelite, a number of sulphides. Similar qualitative composition of magmatic and post-magmatic minerals demonstrates metallogenic specialization of parent granite magma. Predicted mineragenic significance of research in the field of mineral forms evolution of rare elements accumulation in ore-bearing granites and metasomatites is associated with possibilities to assess metallogenic specialization of parent granite magma. Understanding of accessory paragenesis evolution should serve as a base for exploration geo-technologies in the Far East metallogenic province.
Data are presented on the geology of areas of rare metal granites proliferation in the Russian sector of the Pacific Ore Belt that make one take a fresh look at the East Asian granitoid area to update its metallogeny. History is reviewed of studying rare metal granites of the Russian Far East. As a rule, these are found in the vicinity of major tungsten-stanniferous ore deposits, except much later than discovering the former, at the stages of their assessment and survey. Rare earth granites are usually missed by the geologists during the early stages of regional geological surveys due to their small size, weak eroding and external similarity with earlier granites. Using the examples of the Central Polousny, Badzhal and Kuyviveem-Pyrekakay regions the structural and geological conditions are characterized of localization of rare metal granites. Comparative analysis of geological situations made it possible to formulate the areal character of manifestation of rare metal granites; their confinedness to late Mesozoic orogenic arched uplifts of bogen structures above deep granitoid batholiths; positioning in the areas where longitudinal and transversal deep laying faults cross; gravitation to the environs of pre-Cambrian median masses. Similarity of structural-geological conditions for manifestation of the well-studied ore-containing granites serves to confirm the hypothesis on the joint stage of late Cretaceous rare metal magmatism in the Russian sector of the Pacific Ore Belt and the existence in the region of a magmatic super-province – the Far East belt of rare metal granites that includes the Novosibirsk-Chukotka, the Yana-Kolyma and the Sikhote-Alin rare metal – granite provinces.
The history of tectonic development and granitoid magmatism of Northeast Asia in the late Mesozoic is considered. The variety of tectonic situations and granitoid magmatism are favorable circumstances for the solution of many fundamental problems in geology, but tectono-magmatic division into districts is complicated owing to variability of the composition and the structure of the Earth’s crust. A rational approach to the tectonic division into districts of a region by the research of granitoid magmatism based on determining consolidated crust blocks with various tectonic history is offered. Pre-mesozoic and mesozoic structures of the Far East, among which primary and superimposed on the Precambrian and Paleozoic base Verkhoyansk orogeny prevails, are determined. The conclusion on the important role of middle massifs and passive margins with a thin Riphean-Paleozoic cover in geodynamic development of the Far East is drawn. The mesozoic activization of ancient structures along with young granitoid magmatism is established. The driving force of the Pacific ore belt granitization was the interaction of the Paleo-Pacific Plate and plates in Northeast Asia in the middle-late Mesozoic. The history of regional tectogenesis and granitoid magmatism in the late Triassic – Eocene (230-33,7 million years) taking into account the latest geodynamic concepts is tracked. The place in tectonic history of the Asian continental margin of plutonic and volcanic-plutonic belts is determined. Four stages of tectono-magmatic development of the Far East are established: the Jurassic and the early Cretaceous collisional, the early Cretaceous upsubduction, the late Cretaceous upsubduction-transform and the late Cretaceous – Paleogene rift-related. The directed constructive evolution of the Earth’s crust of the Far East is established: origin and building of ancient cratons on margins of the continental crust sated with granitoid intrusions, increase of a silica acidity and alkalinity of the granitoid magmas and formation of late Cretaceous ore-bearing lithium-fluoric granites at the final stage.
Taking into consideration published and author's data, occurrence of areas of rare-metal granitic magmatism in Central and East Asia is investigated. The Far East Belt of lithium-fluoric granites and ongonites is defined. Reasons and history of development of rare-metal granitic belts in North-east Asia are discussed. The conclusion that the Far East Belt of lithium-fluoric granites controls the largest tungstentin fields of the Far East is drawn.
In terms of current research, the methodological comparison of the evolutional crystal morphological analysis and the thermodynamic approach to the zircon thermometry was carried out. The complex application of the both methods is the most appropriate to assess the thermal evolution of the granites. The main features of the thermal evolution in granites of the Verkhneurmiysky massif were revealed. The obtained trends of the thermal evolution confirms the existing conception of the geological evolution of the Badzhalskaya volcanic zone.
Zwitters are metasomatic rocks associated with rare-metal granites. Petrological, geochemical and mineralogical features of zwitters are given. For dark micas features of chemical composition and type of structure is described. Geochemical specialization of metasomatic solutions is characterized. Data about accessory minerals are given.
The main lines of monazite-(Ce) and xenotime-(Y) composition evolution were established in granitoids of the Verkhneurmiysky massif in Amur River region. It is suggested to use revealed features of accessory phosphates composition for a regional partition of granitoids and the assessment of intrusive massifs orepotential.
Having used electron microscopy permits and microanalysis systems for monitoring the general chemical composition of the sample researched forms of occurrence of toxic elements in the granitoids one of regions. As a result, studies have established stable and unstable forms of occurrence of toxic elements. Concluded that secondary hydrothermal forms of concentration of toxic elements may constitute an environmental hazard. Two cycle scheme proposed geoecological monitoring, providing samples of sediment and flowing waters of the river basins.
In the Mesozoic history of the volcano-plutonic magmatism of Badzhalsky area the fourth Late Cretaceous ongonitic stage is specified. The ongonitic magmatism of the Amur River region was evolving during several hundreds of thousand years, had cellular nature and eventuated in the zinnwaldite-microcline-albite granitoids formation with rare-metal accessory complex. In the near-contact zone of the Verhneurmiysky massif Pravourmiysky ongonitic complex, which controls the biggest tungsten-stanniferous deposits of the area and includes ongonite dykes and rare-metal granites of the Dozhdlivy intrusive dome, is determined.
Having used electron microscopy permits and microanalysis systems researched typomorphic features of the zircons from Verchneurmijsky granite massif in Priamurye. Crosscutting study of the zircon crystal morphology and ultimate composition to predict peculiar properties of mineragenesis conditions and afford opportunity to draw sharp disjunction of zircon features from different intrusive phases. Features of the zircons can be used at regional partition of intrusive formations and searches of rare-metal granites.
Having used an optical and raster electronic microscopy were analyzed a topaz granites with accompanying them ongonites discovered for the first time in Chaunsky area of Chukotka. Finding history, specifics of geological location, mineral composition and rock structure are described. Their connection with stannane orebody is considered. The topaz granites have essentially albite composition, contain zinnwaldite, topaz, fluorite and first located in Far East granites wolframoixiolite. The pyrkakajsky intrusive complex of rare-metal granites is allocated. A conclusion about the development possibility of Chaunsky rare-metal deposits potentials is drawn.
The Kamentsev I.E. and Sorokin N.D. method is used to investigate the dependence of Al-Si-ordering and structure of alkaline feldspars decomposition in different granites from the Severny massif (Chukotka) under thermobaric conditions of their crystallization. The temperature and pressure on the granite system in the initial period of feldspars ordering are determined quantitatively for the first time for the region. Progressive pressure change which exceeds lithostatic load by 750 МPа at the late stage of lithium-fluoride granites formation is revealed. It is hypothesized that the deposits similar to explosive ore-bearing breccia can be discovered in the Chukotka. The conclusion on possibility to apply the Sobolev-Dobretsov concept of superpressure to interpret the process of rare-metal magmatism is drawn.
Рассматривается проблема прогнозирования оловянного орудонения в Баднальском районе с точки зрения рудно-формационного анализа. Обосновывается вывод о переходном характере оруденения. Намечается рациональное направление разработки критериев прогнозирования оруденения, связанное с изучением петрографических геохимических особенностей руд и метасоматов.
Изучаемое месторождение расположено в пределах малоисследованного рудного района, что делает необходимой разработку критериев локального прогноза подобных объектов. Основой для такой разработки должно стать, в частности, исследование структурной позиции метассмагитов и руд ...