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DEPENDENCE OF STANDARD OF FINENESS OF FREE GOLD OF HYDROTHERMAL DEPOSITS ON COMPOSITION OF HOST ROCKS
It is generally believed that the standard of fineness of gold of hydrothermal deposits is determined by the types of sources of the initial fluids, the ratios of Au and Ag in them, P, T and the depths of deposits formation as well as the composition of the host mineral paragenesis. This study shows the decisive role of an additional factor and namely the alkalinity of ore-bearing rocks. In the process of presternal and synergistic metasomatosis, they can additionally enrich deep Na or K fluids, which, in turn, can significantly change the solubility of Au and Ag in them. Using the example of three gold ore deposits, the following relationship is established. Terrigenous rocks of Na-K specialization of the Tokur deposit (Russia) have slightly changed the Na/K ratio in the initial potassium fluids; as a result, intermediate and low-grade gold was deposited in ores (811–691 %). The fluids of the Odolgo (Russia) and Kalgoorlie (Australia) deposits, which were formed in the Na specialization rocks, were significantly enriched in sodium during metasomatosis. The standard of fineness of gold deposited in the ores of these deposits is above 900 %
Read MoreOCIO-ECONOMIC FACTORS OF TECHNOSPHERIC FIRES: EXPERIENCE OF STATISTICAL ANALYSIS
Technospheric fires are considered as one of the risks to the sustainable development of the Russian regions. Spatial differentiation of their frequency is associated with a number of socio-economic characteristics of the areas that directly or indirectly describe the susceptibility of their infrastructure to fires and the degree of risk-taking behavior among the population. Numerical analysis for the period of 2007-2016 was performed. For the country as a whole, the overall crime rate, per capita sales of vodka, specific number of disabled people, and people living in nursing homes, the level of per capita income relative to the subsistence minimum were significant characteristics. In the groups of regions ranked by the deviation from the average population, the significance of these indicators is not the same. In certain ranking groups, socio-economic indicators that did not describe the country as a whole turned out to be significant: share of dilapidated housing and housing equipped with central heating, share of people registered as alcoholics, the level of actual final consumption and unemployment.
Read MoreGEOMORPHOLOGICAL RESEARCH FOR SEARCH OF PLACER GOLD IN WESTERN TRANSBAIKALIA
Geomorphological studies carried out in one of the areas of the West Transbaikalia of placer gold revealed the existence of links between the morphology of the river valleys, in particular the nature of longitudinal profiles of streams of different orders with the results of heavy concentrate shooting. The most significant convergence found for channel flow II-III orders regardless of slope exposure and rock-mineral composition of rocks eroded.
Read MoreCONTENT OF METALS IN YANYGHULPYA RIVER ON THE TERRITORY OF THE KHMAO-UGRA
The article contains the results of studies of the chemical composition of natural waters and bottom sediments of one of the tributaries of the river basin of North Sosva – Yanyghulpya River. The increased concentrations of the analysed parameters in surface waters are mainly due to natural origin in the context of the increasing influence of the oil and gas complex on the environment. Conducted studies enable the estimation of the presence of anthropogenic effects on water bodies and establish the relationship between the chemical composition of water and alluvial sediments.
Read MoreNATURAL ELECTRIC FIELDS OF ELECTROKINETIC NATURE OF GATCHINA SOURCES
The paper shows the results of studying the natural electric field of electrokinetic origin. The works were carried out on a site with pronounced activity and relative stability of filtration processes near one of the “Gatchina geysers.” The sources are self-bottling wells operating almost continuously for several decades. The study includes the research of the potential of the natural electric field profile and azimuth observations. The results show the presence of weak anomalies with an amplitude of up to 12 mV. The configuration of negative anomalies corresponds to what is expected in the presence of filtration processes in the direction “from the reservoir.” The local elongated anomalies of the positive sign correspond, in the authors’ opinion, to the faults in the underlying limestone deposits where downward filtration occurs. Azimuth measurements correspond to the results of the profile and allow identifying the direction and intensity of filtration processes in the local area.
Read MoreON AGE OF SEDIMENTATION MASSES OF VALLEY OF SELENGA RIVER (WESTERN TRANSBAIKAL)
The terraced complex of Selenga river is mainly characterized by aquatic environments of sedimentation. According to lithofacies and paleo-hydrological analyzes, high terraced levels are characterized by lake-river origin. The formation of their sedimentary masses occurred in the lower-middle neopleistocene, as evidenced by radio-thermoluminescent dating. Low floodplain terraces of alluvial genesis were formed in the Late Neopleistocene. The revealed patterns of sedimentogenesis are similar to the processes of sedimentation in intermontane troughs of the Baikal rift zone and indicate the unity of regional cycles of Quaternary sediments formation in the Baikal and Transbaikal [7, p. 30].
Read MoreHOLOCENE EOLIAN MORPHOLITHOGENESIS IN RIFT VALLEYS OF NORTH-EASTERN BRANCH OF BAIKAL RIFT AREA
Land deflation in Western Transbaikalia in the middle of the 20th century happened largely due to anthropogenic factors. Small centers of bare moving sands remained to the north, in the western part of the Stanovoy Highlands, in the system of the Muya rift valleys, as they were not influenced by anthropogenic impact. It was established that in the mountain-taiga zone, under favorable geomorphological conditions, with small winds, small areas of bare moving sand can form. But modern climatic conditions contribute to the self-overgrowing of such areas, and this indicates that global warming has not yet led to aridization of the climate in the region under consideration.
Read MoreNEW GEOCHRONOLOGY DATA ON EOCENE-OLIGOCENE VOLCANISM OF KRASKIN RIFT-RELATED BASIN (SOUTH-WESTERN PRIMORYE)
K/Ar and Up/Pb (by zircon) isotope-geochronological study of volcanic rocks of the Kraskin rift-related basin in the south-west of Primorye was carried out. A representative collection of specimens from stratotypic (support) sections of Zaisan basalt-andesite-dacite and Krasin dacite-rhyolite complexes was studied. Based on the data obtained, an assumption was made about the possible manifestation of two volcanic impulses – approximately 55.5 and 43.8 – 33.5 million years ago. It is shown that the main stage of active volcanism within the basin lasts for about 10 million years – from 43.8 to 33.5 million years ago, which was characterized by the synchronous eruption of volcanic rocks of basic and acidic composition.
Read MoreGENETIC FEATURES OF JAMGYR DEPOSIT (WESTERN TIEN-SHAN) RESEARCH ARTICLE
The article is devoted to the studies of the genesis of Jamgyr gold deposit, based on the data from the study of its mineralogical, tectonophysical, thermodynamic, geochemical features and literature data on similar geological objects. The stages of the deposit formation are highlighted, the main physicochemical parameters of ore formation are determined. As a result of research, it was suggested that there are ore bodies of different genetic types within the same deposit.
Read MoreON ORIGIN OF PRECAMBRIAN IRON-ORE PRODUCTS OF KMA
The paper presents a number of hypotheses on the formation of ferruginous quartzites of the Kursk Magnetic Anomaly (KMA) on the example of the Mikhailovsky field. Terrigenous-sedimentary, volcanogenic-sedimentary, metasomatic, magmatogenic, and cosmogonic hypotheses of the formation of glandular precambrian glandular horizons are considered. The article presents the results of a study of the genetic conditions of the origin of ferruginous quartzites by conducting vacuum-deciptometric studies. According to the results, it is revealed that ferruginous quartzites are of polygenic origin.
Read MoreTYPOMORPHIC FEATURES OF SYNTHETIC DIAMONDS AND POSSIBLE WAYS OF TECHNOGENIC CONTAMINATION OF NATURAL OBJECTS
Widespread use of synthetic diamonds as an abrasive material and the appearance of synthetic diamonds on the market of jewelry is currently a serious problem as there is a possibility of changing the pricing policy on the diamond market and the risk of contamination of natural objects when looking for new primary diamond deposits. This paper discusses the main typo-morphic features of the most widespread brands of synthetic diamonds and proposes criteria to identify the authenticity of primary diamonds of known and new genetic types and eliminate the possibility of inappropriate expenditure of funds for the study and exploration of unreliable objects.
Read MoreCHEMICAL COMPOSITION OF WATER OF MAN-MADE WATER BASES OF EASTERN TRANSBAIKAL
The chemical composition of waters of the open-cut lakes of six ore deposits located in the Transbaikal region was studied. The maximum degree of anomaly is characterized by the water in the quarries of deposits containing an increased amount of sulphide minerals in the ores and host rocks. They are acidic and strongly acidic with a high content of sulfates and heavy metals (Fe, Al, Zn, Cu, Mn, Ni, Cd, etc.) and mineralization of more than 2–3 g/l of water. The study of the distribution of the elements in the water column of one of the open-cut lakes showed a significant vertical heterogeneity, which is reflected in a significant increase with the depth of water mineralization, the concentrations of sulfates, iron, zinc, lead, arsenic and aluminum.
Read MoreMETHODOLOGICAL ASPECTS OF CARRYING OUT PREDICTIVE ESTIMATE OF THE JAMGYR DEPOSIT (WESTERN TIAN SHAN)
The article is devoted to the study of the use of various geological methods for predictive estimate of one of the gold ore objects in Central Asia. The relevance of this topic is due to the fact that the Jamgyr deposit under consideration is being successfully developed at relatively low costs for preliminary exploration work, which is associated with the analyzed use of the complex of various research methods at the early stages of its exploration. The data of the article can serve as the sufficient methodological basis for conducting predictive metallogenic studies in the territory of the Russian Federation.
Read MoreRARE METALS IN TECHNOGENICALLY TRANSFORMED WATER OF ZHYREKENSKY, SHAKHTAMINSKY AND BUGDAINSKY MOLYBDENUM DEPOSITS (EASTERN TRANSBAIKAL)
Acid, near-neutral and slightly alkaline waters of predominantly sulfate anionic composition have been formed within the limits of the mining operations of the Zhyrekensky, Shakhtaminsky and Bugdainsky molybdenum deposits. Maximum concentrations of rare metals are characteristic of highly mineralized acidic sub-dump drainage effluents of the Bugdainsky deposit. Here predominant accumulation of rare-earth elements, cadmium, lithium, gallium, and rubidium is recorded. The fractionation of rare-earth elements is studied, and a significant difference in the configurations of their profiles in water and rock is shown. The practical significance of the study is due to the solution of the problem of preserving water resources regarding the mining production impact, as well as the necessity to identify possible raw materials sources of rare metals.
Read MoreSCIENTIFIC BASIS OF GEOLOGICAL PROCESS CONTROL IN TECHNOGENIC MINERAL FORMATIONS
The article presents the forming processes of technogenic and mineral formations (TMFs) – technogenesis and subsequent transformation of the composition and structure of TMF – technogenesis. The authors studied technogenesis on the example of gold-bearing technogenic placers. The processes of TMF conversion lead to the release, transfer, and accumulation of gold-bearing phases inside man-made dumps. Management of the processes of technogenesis leads to the creation of nature-like production technologies. Directions on the management of the formation of gold concentrations in TMFs were allocated. Experiments on the accumulation of gold on geochemical barriers were carried out.
Read MoreANALYSIS OF LITHOLOGICAL COMPOSITION AND COLLECTIVE PROPERTIES OF BREEDS OF ACHIMOVSKY HORIZON ROCK BEDS (ACh1, ACH2, ACh3) OF ALEKHINSKY PRODUCTION FIELD OF KHMAO-UGRA
The conditions of the formation of deposits of the Achimov Neocomian horizon are studied in the article. Specific features of the change in physical properties (permeability, porosity) of Achimov deposits that come with the change of depth within the Alekhinsky deposit are considered. The analysis of changes in the formation reservoir properties of the oil and gas bearing deposits of the Achimov suite in the territory of the Khanty-Mansiysk Autonomous Okrug, Yugra, is carried out. It is established that the rocks of the Achimov rock bed represented by compacted sand and coarse-grained siltstones exhibit uneven changes in the formation reservoir properties due to the complex geological conditions of the deposits formation.
Read MoreRARE-EARTH MINERALIZATION DISTRIBUTION BY ORE TYPES AT EXPLORATION HORIZONS OF KUTESSAI-II DEPOSIT
The distribution of particular rare-earth elements along the horizons has a certain regularity and depends on the zone sequence in the distribution of rare-earth minerals down the section of the deposit. For each of the intermediate horizons of the deposit, certain types of industrial ores and their peculiar rare-earth mineral associations are inherently characteristic, the composition of which varies naturally concerning the deposit section.
The distribution of rare-earth mineralization is controlled by certain structural elements that existed at one or another stage of the formation of the deposit, hence individual parts of the rod-shaped ore body acquire different practical significance for different types of mineralization [3], [4, P. 115-116].
Read MoreGEOLOGICAL STRUCTURE AND PRACTICAL SIGNIFICANCE OF SEDIMENTATION MASSES OF INTERMOUNTAIN AREAS OF WESTERN TRANSBAIKAL
The terraced complex of the Selenga River and its large tributaries in the intermountain areas of Western Transbaikal is composed of sedimentation masses of different thicknesses, mainly of sand composition and aquatic genesis. The results of investigations of the granulometric composition of deposits showed a high degree of their suitability as building materials for the production of silicate products of autoclave hardening, reaching absolute values in separate basins. The extraction can be carried out all the year round by a mechanized career method, which will completely satisfy the demands of the construction industry in this region. A good transport infrastructure – the presence of a wide network of roads and railways will allow exporting raw materials outside its borders. The presented materials can be used at the stages of prospecting and exploration for silicate sands. The basis for this was the author’s original material obtained directly in the course of geological fieldwork.
Read MoreGEOLOGICAL STRUCTURE AND PRACTICAL SIGNIFICANCE OF SEDIMENTATION MASSES OF INTERMOUNTAIN AREAS OF WESTERN TRANSBAIKAL
The terraced complex of the Selenga River and its large tributaries in the intermountain areas of Western Transbaikal is composed of sedimentation masses of different thicknesses, mainly of sand composition and aquatic genesis. The results of investigations of the granulometric composition of deposits showed a high degree of their suitability as building materials for the production of silicate products of autoclave hardening, reaching absolute values in separate basins. The extraction can be carried out all the year round by a mechanized career method, which will completely satisfy the demands of the construction industry in this region. A good transport infrastructure – the presence of a wide network of roads and railways will allow exporting raw materials outside its borders. The presented materials can be used at the stages of prospecting and exploration for silicate sands. The basis for this was the author’s original material obtained directly in the course of geological fieldwork.
Read MoreEXPERIMENTAL STUDY OF MELTING IN THE FORSTERITE NORMATIVE PART OF THE СаО-MgO-Al2O3-SiO2 SYSTEM IN CONNECTION WITH THE EXISTENCE OF THE “ECOLOGITE BARRIER”
We conducted experimental study of the liquidus phase relationships in the forsterite-normative region of the phase diagram of the СаО-MgO-Al2O3-SiO2 system in the pressure range of 2.5-3.0 GPa. The existence of two peritectic melting reactions Opx+Fo+L=Cpx+Ga и Opx+L=Cpx+Ga and one eutectic reaction L=Cpx+Opx+Ga+Fo is established. It is shown that at the pressure of 2.5-2.6 GPa and temperature of 1500 OC, there is a non-variant equilibrium (L, Cpx, Opx, Ga, Fo). At the point of its existence, the liquid composition is in the Mg2Si2O6-Al2O3-Ca2Si2O6 plane. From the point of view of this non-variant equilibrium, the reaction beam is L = Cpx + Opx + Ga + Fo in the direction of high temperatures and high pressures, while the reaction beam Opx + L = Cpx + Ga leaves the point of this non-invariant equilibrium towards high pressures. The reaction beam in the direction of low pressures is Opx + Fo + L = Cpx + Ga. It is shown that the singular non-variant equilibrium (L, Cpx, Opx, Ga, Fo) is a model of the “eclogite barrier,” which was discussed in the works of V.А.Zharikov and V.S.Sobolev in connection with the problem of the composition of primary ultra-basic magmas evolution to granite melts.
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