The study of native gold from several ore zones of the Pioneer field (Amur). In the samples found: nano-gold of various morphology, varying size and composition, as well as complex micro- and nanostructures (film, film layered rhythmic, globular, fine disperse, etc.). In clay-micaceous mineral phases associated with native gold, an isometric and spheroidal nanogold visible under an electron microscope with particle sizes ~ 30–600 nm and a composition of both pure gold (sample 1000 %) and silver impurities (sample ~ 980 %). In the matrix of the same mineral phases, an invisible ultra-thin nanogold was detected, which is recorded by energy dispersive X-ray analysis (size < 30–50 nm, its sample is 1000 %). The genesis of the above types of nanogold is associated primarily with imperfections (defects) in the crystalline structure of the minerals that make up the gold-associating rock. These defects were geochemical barriers on which thin and ultra-thin gold was deposited. A xenomorphic nano-gold is also mounted on the surface of a row of golden, with elongated shapes dominating the particles. The particle sizes of this gold range from the first tens of nanometers to 600–700 nm, although there are particles up to 1000 nm in length and sample 803 %. Various film and globular structures, represented by stratified rhythmic nano-formations consisting of alternating gold films, planar and curved films on the gold surface and globular particles, have been identified in a number of samples of native gold (globules) of gold. The thickness of the films generally varies in the range of ~ 50 to 450 nm, and the size of the globule – from 250 to 670 nm, the composition is different. Mean sample of gold films from the Southern Ore Zone 948 % in Intermediate 880 %. The complex structure of the gold with the presence of various micro- and nanostructures indicates the multi-stage processes of formation of native gold in different ore zones of the Pioneer deposit.

The morphology and chemical composition of minerals of the Khorogochi silver ore occurrence (Upper Amur region) were studied by the analytical scanning electron microscopy. The mineral association is represented by high-grade native silver, basically silver minerals (silver sulphide, sulphoantimonites and silver sulfoarsenides), Ag-containing (fahl ore and galenite), as well as a number of associated minerals (pyrite, chalcopyrite, sphalerite, loellingite, ankerite, hydromica-smectite, etc.). Based on the revealed chemical composition of silver minerals and associated minerals, the features of their spatial relationship, as well as experimental data known from the literature on the resistance of silver-containing systems, the formation temperatures of silver mineralization, which fit into the range of 300–100 oC, and the order of crystallization of its constituent minerals were estimated – from multicomponent compositions with a low silver content (Agtennantite-tetrahedrite, proustite) to compositions with a high content of noble metal (stephanite, polybasite, pearceite, acanthite, native silver). The ore body of silver mineralization in the ore-placer cluster Khorogochi-2 is spatially dissociated from the ore sources of gold-silver mineralization.

The paper describes a rare Au–Bi sulfde (jonassonite) from the Belogorskoe iron deposit (Sikhote-Alin), the ore bodies of which are composed of metalliferous sediments that underwent contact metamorphism (T ~550 °С, Plithostatic ~1.5 kbar) and late hydrothermal processes (T 350–415 and 271 °С or slightly lower). Jonassonite is found in products of hydrothermal alteration of metamorphic bustamite-andradite (with a low amount of Mn-bearing hedenbergite, scheelite, lollingite and baryte) rocks composed of calcite, fuorite, native bismuth, bismuthinite, joseite A, an unnamed AgBiS2 phase, cosalite, Mo-bearing scheelite, povellite-molybdenite and other minerals. Jonassonite is intergrown with anhedral calcite aggregates in andradite and forms grains with sections (~5 ? 7 µm) close to ellipsoid shape. The mineral contains up to 2.29 wt. % Te, which most likely isomorphically substitutes S. Jonassonite formed at a temperature not exceeding 271 °C during hydrothermal alteration of metamorphic mineral assemblages.

The paper presents the data of analytical scanning electron microscopy and mineralogical methods for studying the morphology and chemical composition of spiral man-induced products, metal spheroids and native gold from the alluvial mining waste. In all samples, including the tungsten “spiral”, mercurous gold was found. The spheroids were diagnosed as lead ones with a fine impregnation of alumina-silicate substance, antimony and copper ones with autigenic isometric and xenomorphic mineral deposits on the surface, etc. The inclusion of carbon in many newly formed minerals confirms the leading role of this element in the process of technogenic mineral formation as a reducing agent. The identified chemical diversity of numerous ore and rock phases is explained by complex physico-chemical processes occurring in the technogenic system, in which not only the residual gold is transformed, but also new ore-mineral complexes, including gold-containing ones, arise.

Research subject. The weathering crust of Proterozoic slates in the Neklya River basin and Paleozoic granites in the Nizh- neselemdzhinsky gold-bearing node (NGBN) in the Tatarka River basin.Methods. The research was carried out using the methods of atomic absorption, X-ray fluorescent and mineralogical analysis of rocks and minerals. The method of raster electron microscopy was used to study the element structure, morphological and microstructural features of minerals.Results. Specific features of native gold from the weathering crust of NGBK were defined. It was established that the NGBN weathering crust contains both hypogene gold, partially changed in the course of hypergenesis, and neogenic gold. A considerable share of gold is of high purity (1000%o). Occasionally, gold in the form of complex accretions from grains of different morphology and structure is present. A specific feature of weathering crust gold is its interpenetrations within the rock matrix of a varying mineral structure. Gold-bearing carbonaceous structures in the form of films and outgrowths on gold grains were revealed; the presence of carbon in rock components associating with the noble metal was defined. In the crust, the participation of carbon in physicochemical processes was established, as a result of which the release of Au, encapsulated in minerals-concentrators, and its redeposition on geochemical barriers occur. Gold nanoparticles can be long-acting growth centres in the host rocks, first coalescing with each other to yield nanoformations, then microforms, etc. In the weathering crust of gold deposits, both the transformation of the hypogenic noble metal and the formation of its new forms occur.Conclusion. This work contributes to the expansion of the mineral resource base of gold in the Amur Region, including through such unconventional sources as the NGBN weathering crust.

Over tens of years of mining and processing of ores and placers of gold in the world a huge amount of wastes originated in the form of spoil heaps and tailing dumps, in which the content of valuable components allow them to be considered a real additional resource of precious metals. The aim of the work was to establish the changes that took place in time in the spoil heaps of gold mining and to determine the prospects of the technogene placers as a potential source of the precious metal. The investigations were carried out with the use of the methods of the analytical raster electron microscopy and mineralogical and atomic-absorption analyses. On the example of the Nizhneselemdzhinsky gold-bearing node of Priamurye we have done the compatative analysis of the mineral and granulometric composition of the original and developed placers. It is shown that through the technogenesis the mineral composition of the deposits changes including the process of decomposition of the lead and iron minerals with a partial reduction to a native metal. In addition to the native gold in the technogene placers there have been found the following minerals with a high content of the precious metal: rutile, monazite, magnetite, metallic lead, galena, ilmenite, and zircon. The content of free gold in dumps is 190 mg/m3 in the average. The main amount of it (about 83%) consists of the fine gold (< 0.5 mm). We have studied the chemical composition of the native gold and associated rocks. It has been established that the gold has a multiphase composition. The phases are for the most part the gold amalgams and have two-, three-, and four-component compositions (Au-Hg, Au-Ag-Hg, Au-Hg-Pb, Au-Ag-Hg-Pb). About 30% of gold of the technogene placers have a high standard of fineness (~980‰). Almost all native gold is in close intergrowths with the rock-forming matrix of different composition: hydroalumosilicates, oxides, and hydroxides of Fe, Mn, and Pb, highly carbonaceous and carbon-bearing formations, and so on. Under the action of the physicochemical and biochemical process in the technogene placers different transformations of the native gold take place: purification at the expense of the silver evacuation; decomposition of the minerals-concentrators of gold; precipitation of micro- and nano-gold at the geochemical barriers with the formation of the so-called “new” gold (from nanoformations to micro- and macroforms). Through the operation of the technogene placers one should take into account the fact that the ore minerals in them have high concentrations of heavy metals and radioactive elements, and the gold has a complicated multiphase and multicomponent composition, and ¾ of it is amalgamated. The data obtained give the additional information for the elaboration of technologies for the development of the prospective gold-bearing technogene placers.

Mass cobalt-rich ferromanganese microcrusts and nodules similar in morphology and chemical composition to cobalt-rich ferromanganese deep-ocean crusts were found in Cenozoic volcanic rocks in southern Primorye. Research has shown that ore genesis of this type is genetically related to argillization and destruction of siliceous rocks by CO2-rich fluids, which is confirmed by experimental data on carbon erosion of iron-containing materials. Two types of this fluid ore genesis are recognized: (1) relatively high-temperature (vapor-condensate), related to late volcanic processes and fracture gas infiltration, and (2) low-temperature (vapor-liquid-condensate), controlled by degassing followed by carbon mobilization (gasification). Primarily colloidal ferromanganese segregations have high contents of Co, Ni, Pb, Cu, and Ce, typical of oceanic ore genesis. Regardless of the concentrations of these metals in the protoliths, their contents in microcrusts are similar (n-10n wt.%). This indicates the same ore genesis mechanism and similar sorption properties of the colloidal ferromanganese material formed. Barium-and cerium-rich ferromanganese microcrusts and nodules are abundant. Condensed drops of iron-containing platinum were found in apobasaltic nickel-rich ferromanganese segregations. There is a cerium paradox expressed as a minimum or a total lack of cerium among rare-earth phosphates associated with ferromanganese microcrusts. Fluid destruction and oxide metallization of ocean-floor basalts are assumed to be the main source of metals for oceanic ferromanganese crusts and nodules. (C) 2018, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.

The processes of fluid destruction of various silicate rocks under diffusion of flows of compressed gases (mainly carbonaceous) were studied. The gas condensate nature was ascertained for the forming alumoslilicate and ore (cobalt–iron–manganese hydroxide) substances produced under this fluid destruction in the forms of microcrusts and microconcretions. The ore condensates contained in high concentrations the typomorphic elements of oceanic ferromanganese formations (Mn, Co, Ni, Cu, Pb, Ce, and Pt). The elemental composition of the ore oxide substance formed under the destruction of various silicate matrices exhibits a definite degree of endemism with prevalence of the Co–Mn association. The pronounced concentration of barium is related to the substantially carbonaceous composition of the fluid systems. A cerium paradox is revealed: Ce3+ is oxidized into Ce4+ and absorbed by ferromanganese hydrogel and the minimum of cerium appears in rare-earth phosphates.

Contrary to the popular opinion that the lower Olenekian Scythogondolella milleri Zone corresponds to the almost entire Anasibirites ammonite zone or its analogs (for example, the Anawasatchites tardus Zone), we have arrived at the conclusion that the Milleri Zone in the southern Primorye region should likely be correlated only with the lower part of Anasibirites-bearing strata: lower member A of the Anasibirites nevolini Zone in the SMID quarry section and the lower part of the Churkites cf. syaskoi Beds overlying the Euflemingites prynadai Beds in the Tri Kamnya Cape section. The conodont assemblages from different facies of the Anasibirites nevolini Zone in southern Primorye differ from each other in taxonomic composition and diversity at the generic level, as well as in sizes of specimens.

Atmospheric aerosols inherent in two areas of the Far East cities such as the Vladivostok and Ussuriysk were studied. Three of the 21 pairs of the samples of fresh snow and dry air suspensions taken in different parts of these cities exhibited the presence of iron, chromium, lead and zinc nano- and microparticles. Therewith, the nanoparticles were registered for the samples taken near the electroplating production enterprises, whereas the microparticles were observed near the roads with an intense traffic.

The paper presents the results of a granulometric and substantial study of nanoand microparticles in air suspensions collected in the snow in the Vladivostok city in winter 2011-2012. Application of the laser particle analyzer for the study of qualitative and quantitative composition of atmospheric precipitations has been shown. Distribution of the particles differing by size and genesis in the city areas with different anthropogenic loads has been revealed.

The Pokrovskoe gold-silver deposit is explored by drill holes. Its gently dipping orebodies (lodes) revealed by core sampling are quarry mined. It is considered that they also consist of gently dipping quartz veins and vein-stringer zones. The performed investigation of the terraces in the exploited quarries made it possible to correct the available present-day concepts. It is shown that their structure is dominated by steeply dipping veins and vein-stringer zones. They are characterized by the northeastern strike in the central part of the deposit and its western flank and the mostly northwestern one in its eastern part. An important role in the formation and distribution of the orebodies belongs to various geological screens poorly permeable for fluids. The main factors responsible for the ore localization in screened hydrogeological systems are revealed with the assessment of the thermal impact of a dacite sill on the formation of the ore-hosting cavities and ore deposition. The electron microscope investigation of the ores substantially widened the spectrum of ore minerals previously unknown in this deposit, including gold-bearing varieties (copper gold and its complex intermetallic compounds). Based on the dominant micrometer sizes of all the ore minerals and their dispersion within the quartz matrix, it is inferred that the deposition of productive ores occurred in nonequilibrium environments.

The results of the study of hydrothermal noble opal are discussed. it has been established that hydrothermal opal differs in its nanostructure and formation conditions from exogenic noble opal. The former is composed of smaller globules without any structuring of closely packed nanoparticles characteristic of exogenic opal. In the course of formation, hydrothermal opal is affected by pneumatolytic annealing related to the effect of high-temperature vapors under an elevated pressure. At the same time, the thermal effect results in the formation of two-dimensional photon zones in the chaotic opal matrix. These photon zones are produced by grids, the cells of which arose from a thermal effect similar to what related to Benard cells. Precisely, these structured blocks and thin films lead to spectral dispersion of light and appearance of iridescence.