The Ilmeno-Vishnevogorsk (IVC) and Buldym carbonatite complexes of the Southern Urals are deformed linear-type carbonatite complexes that underwent tectonic evolution as a result of accretion-collision processes and the Hercynian collision orogeny. The deposits of niobium and rare earth elements are associated with the Ural carbonatite complexes. Nb-REE ore mineralization is represented by the pyrochlore supergroup minerals, aeschynite and monazite. Their compositional evolution and connection with various phases of alkaline magmatism, pegmatite and carbonatite formation, and late postmagmatic (carbothermal) processes were studied. To determine the age and duration of the ore-forming stages, UPb dating of minerals pyrochlore supergroup phases and monazite was carried out. The pyrochlore-group minerals of the Ural carbonatite complexes are represented by calciopyrochlore, rarely natropyrochlore, and kenopyrochlore. Pyrochlore I, rich in U-(Ta), crystallizes in the earliest magmatic phases of the IVC, in the miaskites and carbonatites I of the Central Alkaline Band. In contrast, Ta-(U)-bearing pyrochlore II is formed in the later magmatic phases, in the taxitic miaskites and miaskite-pegmatites, and is present in explosive carbonatite breccias and carbonatites II of the Vishnevogorsk massif. Both varieties of pyrochlore have magmatic characteristics - oscillatory zoning, absence of vacancies in the A-site, and low Nb/Ta <80. Pyrochlore III and Sr-REE-containing pyrochlore IV - with high Nb/Ta >300 and fluorine (4-5 wt%), are formed from fluid-saturated F-containing carbonate systems in carbonatites II of the IVC miaskite intrusions and fenite halos, as well as in carbonatites III and fenites of the Buldym complex. REE minerals - aeschynite-(Ce) and monazite-(Ce) formed in the carbothermalites of the Buldym complex and in fenite halos of miaskite massifs. The morphological features and evolution of the pyrochlore composition indicate the polygenic nature of the ore process, the late low-temperature stage of which is associated not only with Nb but also with REE mineralization (aeschynite, monazite). The results of U-Pb-dating of the pyrochlore- and monazite-group minerals make it possible to distinguish two stages of ore formation in the studied carbonatite complexes of the Southern Urals. The early stage is recorded by U-(Ta)-rich pyrochlore in carbonatites I, the Potanino deposit (378 +/- 5 Ma), and can be correlated with the primary crystallization of the IV & Scy; alkaline rocks and carbonatites at the rifting stage (D-3) of the forming continental margins. Whereas, the late stage is dated at similar to 255-230 Ma yielded for pyrochlores II-IV of the Vishnevogorsk deposit - in taxitic miaskites, syenite- and miaskite-pegmatites, as well as carbonatites II of various ore zones (P-3-T-2), and pyrochlore and monazite - in carbonatites III and carbothermalites of the Buldym complex (similar to 245-235 Ma, T-1(-)2). The late ore-forming stage is associated with palingenic-metasomatic processes of transformation of the Paleozoic carbonatite complexes and the formation of ore-bearing fluid-saturated alkaline and carbonatite melts and fluids at the Ural collision stage and post-collision relaxation.

Object of research. Spinelides of izrandites of the Aleksandrov polymetamorphic complex in the Southern Urals. Purpose of research. Studying of composition of spinel group minerals and coexisting ilmenite in single grains and in different phases in unmixing structures after decomposition of solid solutions, reconstruction of primary compositions of oxide minerals and comparison with the same minerals from Ural-Alaskan-type complexes having an ankaramine affinity. Methods. The study was performed on a Tescan Mira scanning electron microscope at the “Geoanalitic” Center of Common Use (Ekaterinburg). The images were obtained in backscattered electron mode. The composition of minerals was determined in points and using an area scanning facilities of SEM for the unmixing structures of spinels. Results. Chrome spinel containing more than 25 wt % Cr2O3 and corresponding to the earliest stage of crystallization has been discovered in izrandites of the Alexandrovsky polymetamorphic complex in the Southern Urals. The several stages of Cr-Fe-Ti-oxide and rock-forming silicates crystallization were determined. It was shown that during cooling and subsolidus transformation, oxide minerals undergo complex multistage decomposition of the solid solution with the formation of phases enriched in aluminum and ferric iron in equilibrium with ilmenite. The compositions of these phases are distributed along the Cr-spinel solvus. The earliest primary hypersolvus spinels form inclusions in olivine and clinopyroxene. They are characterized by 3–4 wt % of TiO2 and 15–20 wt % of Cr2O3. The late spinel forms inclusions in kaersutite and are situated in the intergranular space. Their compositions are poor in Cr2O3 < 7%, but rich in TiO2 10–25 wt %, corresponding to titanomagnetite and ulvospinel. Conclusions. The composition of rocks, silicate minerals and Cr-Fe-Ti-oxides confirm the similarity of izrandites with ankaramites and tilaites from complexes of Ural-Alaskan-type. High titanium content in izrandites in comparison with similar rocks of the Ural Platinum Belt reflect the geochemical peculiarities of the primary melt which was formed by melting of the metasomatically transformed Mesoproterozoic mantle under the influence of a plume.

Research subject. Zircon of granites in the western contact part of the Adui massif (Middle Urals). Aim. To obtain new U-Pb dating and to clarify the geochronological model of the Adui granite massif. Methods. U-Pb dating of zircon was established using a SHRIMP-II high-resolution secondary ion microprobe (VSEGEI Research Center, St. Petersburg). The major and trace elements were determined using SRM-18, SRM-25, and VRA-30 X-ray fluorescence spectrometers and an ELAN-9000 mass spectrometer with inductively coupled plasma. Results. In terms of chemical composition, the vein granites in the western contact zone belong to the rocks of the granite-leucogranite formation that make up the massif. Their hosting gneisses possess features similar to the granitoids of the gabbro-tonalite-granodiorite-granite formation. Zircons from orthogneisses were found to have a simple structure and a close Th/U ratio (0.6) with wide variations in uranium and thorium contents. Their concordant age ranges from 290–270 million years. Such a wide age range may be due to the loss of lead during metamorphism. The zircon of granites is different. It consists of cores, often clastic in appearance, overgrown with a rim of high-uranium zircon. Zircon grain cores from early (pegmatoid) granites are similar to those from host orthogneiss and can be interpreted as captured from them. The cores of zircon grains in late granites are characterized by a rather low Th/U ratio (0.1) and wide variations in U contents; their dates form a single age cluster with an average concordant age of 270 Ma. The rims, which are characterized by high U concentrations and low Th/U ratios, mark the period of granite formation in the range of 265–250 million years. Conclusions. The interpretation of new and previously published age data consists in identifying a prolong stage of metamorphism and migmatization of the host rocks in the range from 290 to 270 million years, preceding granite formation. The completion of granite formation with the formation of the main phases of the Adui massif corresponded to a time interval of 265–250 million years.

Research subject. Phosphate mineral geochronometers – the international reference sample of Trebilcock monazite from pegmatites with the age of 272 ± 2 Ma, as well as samples of monazite from pegmatites of the Shartash massif and monazite, cheralite and xenotime from leucogranite of the Peshcherninsky stock and diorite of the Khomutinsky massif, Middle Urals. Methods. The composition of minerals was studied using CAMECA SX100 microprobe; Raman spectra were obtained using LabRAM HR800 Evolution confocal spectrometer. Research aim. Study of the internal texture of the grains of phosphate minerals on the basis of their elemental and spectroscopic mapping; analysis of the mineral crystal chemistry and estimation of auto-irradiation doses; microprobe non-isotopic U–Th–Pbtot dating of phosphate minerals; development of the appropriate algorithm for using analytical techniques. Results. It has been shown that the studied monazites belong to the cerium variety with ThO2 content from 1.1 to 17.2; UO2 – from 0 to 0.8; PbO – from 0.01 to 0.23 wt % (detection limits 160, 230, and 110 ppm). When analyzing the PbO content, the background line was interpolated into models of linear background (Trebilcock monazite, monazite and cheralite of the Peshcherninsky stock) and exponential background (monazite of the Shartash massif). It has been shown that for monazite, both huttonite and cheralite types of isomorphism are realized; the non-stoichiometric parameter of its composition β = (Si + Ca)/(Th + U + Pb + S) lies in the range of 0.95–1.05, which indicates the preservation of the U–Th–Pb-system. The analysis of BSE-images, intensity distribution maps of the Th Mα and Pb Mα RE lines, compositional point analyses and the results of spectroscopic mapping of the parameters of the ν1(PO4) vibrational mode testify to high homogeneity of Trebilcock monazite and pronounced zoning of the Ural monazites. It has been shown that the parameters of the ν1(PO4) vibrational mode in monazites are determined by the superposition of two factors, i.e. chemical and radiation disorder. The data on U, Th, and Pb content for different zones of monazite grains were used to perform non-isotopic U–Th–Pbtot dating: weighted average age values for the zones were obtained, and isochron plotting was made on the ThO2* vs. PbO diagram. The datings obtained based on the Trebilcock sample are in satisfactory agreement with the literature. Conclusions. The dating of monazite from leucogranite of the Peshcherninsky stock and the Shartash massif are in agreement with the U-Pb isotopic dating of zircon. The physical and chemical characteristics of cheralite, xenotime, and zircon in samples from the Peshcherninsky stock were analyzed. The U–Th–Pbtot dating of cheralite, xenotime, and zircon was attempted. The described algorithm and analytical methods were used at the Geoanalitik Common Use Center for microprobe non-isotopic dating of phosphate minerals.

The mineral association of siderite with Cu–Fe sulfides, cronstedtite, and goethite were first recognized when studying the Mikheevskoe Cu(Mo,Au)–porphyry deposit. This association is confined to fault zones, where it fills a network of mineralized fractures developed on porphyry- and argillizite-type ores. Minerals of this association were also identified in some argillizite samples of this deposit. The formation conditions of this mineral association and its relation to the evolution of the Late Paleozoic porphyry system or other endogenic–exogenic processes manifested during the subsequent geological history of the study area were studied. The integrated research included microprobe analysis and the measurement of O and C stable isotopes in minerals of the studied association in the “Geoanalitik” (Yekaterinburg) and “Geonauka” (Syktyvkar) Centers for Collective Use. The study of mineral compositions and their relationships indicates that the studied mineral association deposited at temperature of about 70°C from neutral or low-acid solutions with varying CO_3^2 - , HS–, and aSiO2 (aq) contents. The measurements of δ13C (from –5.5 to –18.2‰) and δ18O (from 20.4 to 33.4‰) values in siderite made it possible to calculate the composition of a mineral-forming fluid. It was established that such a fluid has the following parameters: δ18O H2O from –3 to +10‰ and δ13C CO2 from 15 to –28‰. It could correspond to magmatogenic water fluids mixed with Corg-bearing surface water. Based on the obtained results, it is suggested that this mineral association is related to argillizites, the development of which occurred at the last stage of endogenic mineral formation at the Mikheevskoe deposit. Nevertheless, it is not excluded that it may be related with other low-T hydrothermal processes at the stage of Meso-Cenozoic tectonomagmatic activation of the Urals. There is no evidence of the relation of the studied mineral association with weathering crusts.

Transformation of the oceanic crust into the continental one in orogenic belts is an important problem in petrological studies. In the paleocontinental sector of the Urals, a key object for tracing the stages of metamorphism and investigating the origin of anatectic granites is the Murzinka-Adui metamorphic complex. We have analyzed trace elements in zircons and established their genesis, sources, crystallization conditions, and stages of metamorphic events and granite generation in this complex. Zircons compositions were determined by the LA-ICP-MS method. Temperatures were calculated from Ti contents in the zircons. We distinguish three geochemical types of zircons, which differ in the ratios of light and heavy REE, U, Th, Ti, Y and show different values of Ce- and Eu-anomalies and Zr/Hf ratios, which are indicative of different crystallization conditions, as follows. Type I: minimal total LREE content; clear negative Eu- and Ce- anomalies; features of magmatic genesis; crystallization temperatures from 629 to 782 °C. Type II: higher contents of Ti, La, and LREE; low Ce-anomaly; assumed crystallization from highly fluidized melts or solutions. Type III: low positive Eu-anomaly; high REE content; low Th/U-ratio; zircons are assumed to originate from a specific fluidized melt with a high Eu-concentration. Ancient relict zircons (2300–330 Ma) in gneisses and granites show features of magma genesis and belong to types I and II. Such grains were possibly inherited from granitoid sources with different SiO2 contents and different degrees of metamorphism. Based on the geological and petrogeochemical features and zircon geochemistry of the Murzinka-Adui complex, there are grounds to conclude that the material composing this complex was generated from the sialic crust. The main stages of metamorphism and/or granite generation, which are traceable from the changes in types and compositions of the zircons, are dated at 1639, 380–370, 330, and 276–246 Ma. Thus, transformation of the oceanic crust into the continental one was a long-term and complicated process, and, as a result, the thickness of the sialic crust is increased in the study area.

Research subject. The geological structure and rock composition of the Nizhne-Sinyachikhinsky plagiogranite massif, which is part of the Alapaevsk-Sukholozhsky zone, is promising for the Cu(Au,Mo)-porphyric mineralization type, were studied. The aim was to determine the formation features of these rocks and compare them with the productive granitoids of Ural porphyry deposits of similar age. Materials and methods. The mineral composition of the rocks was determined using a JEOL JSM 6790LV scanning electron microscope with an INCA Energy 450 X-Max 80 EDS spectrometer and a CAMECA SX-100 electron microprobe analyser. The rock composition was obtained by X-ray fluorescence spectrometry on a SRM-35 and XRF-1800 spectrometers with the titrimetric determination of FeO. The concentrations of rare and rare-earth elements were determined on an ELAN 9000 inductively coupled plasma mass spectrometer at the Geoanalitik Center for Collective Use of the Ural Branch of the Russian Academy of Sciences. Results. For the first time, an early tonalite-plagiogranite series was identified in the structure of the massif. This series is represented by tonalites of the hypabyssal appearance, broken through by the dikes of plagiogranite-porphyry. It was shown that the separation of plagiogranite-porphyry melts from magmas of the mafic composition occurred at the base of the island-arc construction, and their crystallisation was carried out in an intermediate chamber at a pressure of 1.8–2.3 kbar. In contrast, the plagiogranites of the main phase of the massif were separated from the parent melt in an intermediate chamber located at the level of the upper crust, and their crystallisation occurred at a pressure of 1.5–2.0 kbar. Conclusions. A comparison of the main phase plagiogranites and the isolated early-series plagiogranite-porphyry indicates their similar composition, as well as their similarity in age with the granitoids of the Southern Urals, productive in terms of the porphyry mineralisation type. The concentrations of F, Cl and S in the apatites and amphiboles of the rocks under study is an argument in favour of their belonging to andesitoid formations that are productive in terms of the Cu (Au)-porphyry mineralisation type. The absence of the sulphide mineralisation of this type can be explained by a more significant depth of rock formation and their erosion section.

The article covers the U-Pb dating of minerals belonging to the pyrochlore group from the rare-metal ore deposits of Ilmeny-Vishnevogorsky carbonatite-miaskite complex (South Urals). Individual pyrochlore crystals were dated through a new technique of in-situ U-Pb dating using SHRIMP-II, which was developed at VSEGEI (St.Petersburg). The U-Pb dating of high-uranium pyrochlore (more than 2.5 wt % UO2) was carried out employing laser ablation and ICP-MS. The U-Pb systems of studied pyrochlore samples indicate a multi-stage formation of rare-metal niobium mineralisation. The earliest age of ore formation (378 ± 4.9 ma) is yielded by the U-Pb systems of U-bearing pyrochlores from the carbonatites of the Potanino deposit. This period of ore formation is probably associated with the final stages in the crystallisation of the alkaline-carbonatite magmatic system. The next periods of ore formation (230 ± 1.5 Ma) are widely manifested in the Vishnevogorsky and later in the Potanino deposit (217.2 ± 1.9 Ma), which is probably associated with the remobilisation and redeposition of alkaline-carbonatite and rare-metal substances at the post-collision stage in the evolution of Ural carbonatite complexes.

The paper describes secondary Cu minerals from the oxidation zone of the Saryshagan Cu (Mo)-porphyry occurrence (Western Balkhash region, Central Kazakhstan). The zonal distribution of secondary Cu minerals is shown along the section of the oxidation zone. Malachite and chrysocolla are found in the lower part of the section, whereas chrysocolla and Cu chlorides are dominant in the upper zone. Cu chlorides include atacamite, spangolite and unidentified minerals and are associated with gypsum. The local presence of fissure-hydrogenic U mineralization is established. Figures 4. Table 1. References 22. Key words: oxidation zone, copper deposits, malachite, chrysocolla, atacamite, metatorbernite, Kazakhstan.

Research subject. The article discusses the features of the relationship between biotite and amphibole on the example of magmatogene melanocratic rocks from a number of granitoid massifs of the Urals. These rocks form xenoliths and synplutonic intrusions of the calc-alkaline series of normal alkalinity: gornblenditam, gabbro, diorite, quartz diorite. They are composed of amphibole, acidic or middle plagioclase, in a subordinated quanitity they contain clinopyroxene, biotite, potassium feldspar, quartz.Materials and methods. The composition of the minerals of melanocratic rocks was determined on a JSM-6990LV electron microscope with an EDC-adapter of INCA Energy 450 X-Max 80 in the Geoanalytical Center of the IGG Ural Branch of the Russian Academy of Sciences.Results and conclusions. Wide variations in amphibole compositions and narrow biotite variations caused by exchange processes between the mineral and postmagmatic fluid are shown. The phenomenon of replacement of early magmatic amphibole with biotite is substantiated by the presence of a gap in the crystallization temperatures of minerals, indicating a lack of physicochemical equilibrium between them. Their structural relationships confirm the development of biotite as a result of the replacement of amphibole in accordance with the competent and incompetent phase boundaries. In the first case, the structural packets of biotite are embedded along the silicon-oxygen chains of amphibole, which is expressed in the parallelism of the (001) plane of biotite with the (100), (110) planes of amphibole. In the second case, the development of biotite occurs irregularly, inheriting the system of cracks in amphibole. The distribution of Mg/Fe between biotite and early magmatic amphibole was studied, showing that the magnesia value of biotite is higher than that of amphibole replaced by it. Inverse ratios of magnesia value occur between biotite and post-magmatic amphibole. The equality of the magnesia values of both minerals may reflect the conditions of subsolidus equilibration of the compositions. The problem of choosing amphibole compositions for calculating the PTparameters of the formation of massifs in the Earth crust is considered.

The Murzinka granite area (Central Urals), which combines Murzinka granite pluton and underlying rocks of the Murzinka-Adui metamorphic complex, exhibits an evident wetrending geochemical zonation of magmatism with increasing of Rb, Li, Nb and Ta contents and decreasing ba and Sr contents and K/Rb, zr/Hf and Nb/Ta ratios from vein granites of the Yuzhakovo complex to granites of the Vatikha complex and further to granites of the Murzinka complex (Fershtater et al., 2019). To develop the ideas about geochemical zonation of the Murzinka granite magmatism, as well as about the role of gneisses of the Murzinka-Adui metamorphic complex in the formation of granites, we studied the distribution of trace elements in biotite and feldspars of gneisses and granites. Biotite shows an increase in Li, Rb, Cs, Nb, Ga, zn, Mn, Sc, Sn and Tl contents and a decrease in V, Cr, Co, Ni, Y, zr and ba contents from vein biotites of the Yuzhakovo granites to two-mica granites of the Murzinka complex. The composition of feldspars also changes in this direction: plagioclase is enriched in Li, Rb, Cs, be, zn and depleted in Sr, ba, Ga and Pb and K-feldspar is enriched in Rb and depleted in Sr and ba. The varying trace element composition of rock-forming minerals of gneisses and granites is explained by We-trending change in the composition of a crustal protolith, as well as the formation conditions of granites. Figures 6. Tables 4. References 17.

Research subject . High-magnesium rocks associated with the granitoid massifs of the Urals are represented by gabbro-diorites and their melanocratic varieties (hornblendites), as well as by diorites and quartz diorites. These rocks are composed of amphibole porphyrocrists frequently combined with clinopyroxene and phlogopite immersed in a basis of acid plagioclase with interstitial quartz and potassium feldspar. In addition to a high magnesium content of 0.5–0.8 units, these rocks are characterized by extremely high chromium contents of up to 1200 ppm. Methods . The study of the composition of high-magnesium rocks was performed using an ELAN 9000 inductively coupled plasma mass spectrometer, an SX-100 Cameca electron probe microanalyzer and an energy dispersive device INCAEnergy 450 X-Max 80. The detection limit for Cr 2 O 3 was equal to 0.05 wt. % and 0.2 wt. % for the microanalyzer and the energy dispersive device, respectively. Results . The two main mineral associations related to magmatic and post-magmatic processes are found to be different in terms of chromium behaviour. The average concentrations of chromium oxide in the minerals from the magmatic association varied within the range (wt. %) of 0.10–0.50, 0.29–0.68, 0.08-0.36 and 0.0–1.6 for different samples of clinopyroxene, amphibole, phlogopite and their variations, respectively. The post-magnetic association included minerals representing the products of postmagmatic (hydrothermal) transformation of pyroxenes and alumina amphibole into low-alumina magnesia hornblende, actinolite, titanite, epidote and muscovite. The transformation of chromospinelide at this stage had been accompanied by exchange processes with silicates, as a result of which the silicates were enriched with chromium. The average concentrations of chromium oxide in the minerals of this association were (wt. %) 0.24–0.80, 1.38–3.08, 1.03 and 3.5 in the samples of amphibole, epidote, titanite and muscovite, respectively. Conclusion . It is assumed that the crystallization of the early association of iron-magnesium silicates proceeded from aqueous high-magnesium melts. The subsequent post-magmatic change of such silicates led to the development of phases with a similar and occasionally higher chromium content. This fact can be explained by the interaction of silicates with chromite under the conditions of low fluid oxidation, which was insufficient for the formation of magnetite.

Проведено U-Pb датирование минералов группы пирохлора из редкометалльных месторождений ильмено-вишневогорского комплекса Южного Урала. Для измерения возраста отдельных кристаллов пирохлора была использована новая методика локального U-Pb датирования на вторично-ионном масс-спектрометре SHRIMP-II, разработанная в ЦИИ ВСЕГЕИ (г. Санкт-Петербург). U-Pb датирование высокоурановых пирохлоров (с содержанием окислов урана более чем 2.5 мас. %) проводилось с помощью лазерной абляции и масс-спектрометра с ИСП-МС (DUV-19 и LA-ICP MS). U-Pb система изученных образцов пирохлора свидетельствует о многоэтапном формировании редкометалльной ниобиевой минерализации ильмено-вишневогорского комплекса. Наиболее древний возраст (378 ± 4.9 млн лет) фиксируется изотопными U-Pb системами уранпирохлоров ранних карбонатитов Потанинского месторождения. Этот этап рудообразования, возможно, отражает завершающие стадии кристаллизации щелочно-карбонатитовой магматической системы. Следующие этапы рудообразования широко проявлены на Вишневогорском (230 ± 1.5 млн лет) и позднее на Потанинском (217.2 ± 1.9 млн лет) месторождениях и, вероятно, связаны с ремобилизацией и переотложением щелочно-карбонатитового и редкометалльного вещества на постколлизионном этапе эволюции карбонатитовых комплексов Урала.

The paper presents the results of a study of the chemical composition of the sulfosalts of bismuth from the gold-quartz-sulphide ore Berezovsky Deposit and the eponymous ore district of the Middle Urals. Samples of minerals were obtained from quartz veins located in different parts of the ore area. In the South of the district the veins occur among the granites of the Shartash massif and accompanied by the metasomatic gumbeit formation. Veins in its Central part are located into the dikes of granite porphyry, volcanic-sedimentary rocks, hyperbasites. In the North, the veins are localized in gabbro, hyperbasites, volcanic rocks. Here, as in the Central part, they are accompanied by metasomatic changes of the berezite-listwanite formation. The minerals of bismuth form small isometric, prismatic or needle-shaped secretions, as well as large elongated crystals reaching a length of several centimeters. Their diagnosis and study of the composition was performed by X-ray structural and chemical microanalysis. It is shown widespread among minerals of bismuth sulfosalts of the bismuthinite-aikinite series, consisting of 9 members: bismuthine, pecoite, gladite, stroking, salzburger, krupkaite, lindstromite, khammarite, fridrikhite and dramatically prevalent among sulfosalts that number aikinite. In mineral composition pavonite series revealed cuprapawonite, Cu-benjaminite, benjaminite. Other sulphosalts of bismuth are presented kosalite, nafildite, hodrushite, matildite. The relationship of minerals with each other and the peculiarities of the chemical composition allowed to distinguish several paragenetic associations conform with different stages of mineral formation. With high-temperature stage (360-285°C) connects the deposition of disordered solid solutions bismuthine-aikinte and pavonite series, subsequently undergone to disintegration with the formation of ordered phases of bismuthine, gladite, krupkaite, lindstromite, khammarite, benjaminite. For medium and low temperature stage (285-150°C) was formed aikinite, fridrikhite, krupkaite, salzburgite, nuffieldite cozalite, matildite, together with the Ag-Bi-Galena, tetradymite, hessite and gold. The low-temperature stage is associated with the formation of aikinite together with Galena and gold. Established on the example of the sulfosalts of bismuth sequence of mineral formation reflects not only the consistent evolution of mineral-forming fluids, but the pulsed nature of the hydrothermal activity at individual deposits and at ore field in general.

We have studied mineral and chemical composition of lamproites from Kalymbaevsky Complex the Middle Trias. These lamproites were developed in Magnitogorsk and Eastern-Urals megazones of the Southern Urals. We have established the presence of olivine, phlogopite, diopside phenocrysts. We have registered the presence of globular structures, consisting of sanidine and interstitial glass. We have also shown the presence in the base of rocks microlites of aluminous diopside-augite and alkaline pyroxenes of aegirin-augite series, which previously were taken for alkaline and sub-alkaline amphiboles. We have established high sulfur concentration in the apatite which, without magmatic sulfides in the rocks, witnesses for oxidation of lamproite magmas. For the first time precise geochemical data for microelemental and isotopic Sr, Nd composition of rocks are given. It was found that the South Urals rocks have a intermediate composition between lamproites and potassium alkaline basalts. Their source was the enriched mantle with the value εNdi = +0.7-+3.9. We have shown uncertainty of geochronological data, according to which lamproite magmatism could be initiated 197-240 or 300-310 Ma.

The pebbles from alluvial gold placer deposits of the upper reaches of the Tatarka river in Angara region, Yenisei Ridge, are composed of bismuth minerals: crystal aggregates of native bismuth and pseudomorphic secondary oxides, carbonates, and phosphates. Secondary minerals include bismite, bismuthite, beyerite, waylandite, waylandite-(Ca), and crandallite-(Bi). The pseudomorphs mainly consist of bismite and bismuthite, which form reticulate and concentric cryptocrystalline aggregates, whereas beyerite, crandallite-(Bi), and waylandite-(Ca) form veins. Waylandite occurs in dissolution cavities. The presence of relatively fresh native bismuth pebbles and products of their oxidation in alluvial placers is considered to be a searching indicator of proximal gold and bismuth-bearing deposit.

Two age stages in the formation of high-aluminous gneisses related to the major stages of granite formation of the Uralian mobile belt were revealed in this study. The first stage (372 ± 2 Ma) corresponds to the age of metamorphism of the amphibolite facies and is controlled by intrusion of the tonalite–trondhjemite series under the environment of the continental margin. At the second stage (307 ± 3 Ma), gneiss underwent contact metamorphism under the influence of plutons of the adamellite–granite composition formed during the early episodes of collisional metamorphism.

Using techniques of microprobe analysis and Raman microspectroscopy, a study of the composition, structure, and age of high-uranium zircon from the Sharatash intrusion pegmatite was performed. The presence of a number of zones in crystals having different physicochemical characteristics has been revealed. The Id-e zones affected by a radiation dose of (30–130) × 10 18 α-dec/g were completely amorphized, and their chemical isochron age was estimated at 311.4 ± 7.1 Ma: this is interpreted as the time of zircon formation in the pegmatite. The age of uraninite coupled with zircon is 317.1 ± 2.3 Ma. These dating results clarify the formation time of the final phase (pegmatite) of the Shartash intrusion and determine the upper age limit of hydrothermal gold mineralization (Berezovsk deposit) associated with the granite massif.