| Реферат: | eng: Relevance: to reveal the genetic relationship of ore mineralization with late Jurassic magmatic rocks of the Shakhtama complex for Antiinsky ore occurrence as example. The aim of the research is to determine the genesis of the Antiinsky ore occurrence relying on petrographic, petrochemical, mineralogical-geochemical, isotopic and physicochemical studies. Objects: Antiinsky ore occurrence, as well as some smaller mineralization sites localized within the massif of the same name in the Shakhtama complex. Methods. Mineral composition, texture, structural features, inter-relations between individual minerals were studied with an optical microscope in the reflected and transmitted light. Monomineral fractions of sulfides were collected under a binocular from crushed samples and sulfide concentrates. Chemical composition of sulfide minerals and native gold was analyzed in polished discs using the X-ray spectral method with a JEOL JXA-8100 instrument, as well as by means of scanning electron microscopy (SEM) with a ISM-6510 instrument equipped with an energy-dispersive spectrometer (EDS) of OXFORD company. The isotope composition of sulfur in sulfide minerals was determined in the Center for Multielement and Isotope studies, SB RAS (Novosibirsk). The error of delta S-34(CDT) determination (1 sigma) was 0,1 parts per thousand. Fluid inclusions were studied in transparent polished plates by means of cryothermometry and Raman spectroscopy. Cryothermometric studies were carried out in a THMSG-600 micro thermochamber of Linkam company. The composition of the gas phase of fluid inclusions was studied by means of Raman spectroscopy using a Ramanor U-1000 spectrometer and a Horiba DU420E-0E-323 detector of Jobin Yvon company, Millennia Pro laser of Spectra-Physics company; Con focal Raman Microscope alpha 300R of WlTec company. Analysis of petrogenic components (SiO2, TiO2, Al2O3, Fe2O3, FeO, MnO, MgO, CaO, P2O5, Na2O, K2O, H2O, LOI) in magmatic rocks was carried out by the method of silicate analysis in the Chemical Group of the Center for Geodynamics and Geochronology at the Institute of Earth Crust, SB RAS (Irkutsk). Results. The Antiinsky ore occurrence is situated in the Aginsky tectonic zone of Eastern Transbaikalia and is related to the massif of the same name in the Shakhtama complex. The authors have studied the mineral composition of ores using the modern methods, revealed and characterized the major mineral associations. The paper introduces the detailed data on chemical composition of native gold, sulfide minerals and their isotope composition. It is established that the major productive mineral association is galena-boulangerite with native gold. The results of the studies of sulfur isotope composition of sulfide minerals provide the evidence of the magmatic source of sulfur in ore minerals. The petrographic and petrochemical studies showed that the magmatic rocks of the Antiinsky massif are peraluminium, magnesial, high-potassium reduced granitoids. The obtained data allow us to assume that the magmatic rocks of the Antiinsky massif are the closest ones to high-potassium I-type of granitoids. The fluid inclusion studies of vein quartz from the Antiinsky ore occurrence and the points of mineralization Au 48, 49 showed that their formation took place under similar physicochemical conditions. The formation of early impregnated pyrite-arsenopyrite mineralization proceeded from reduced carbon-dioxide medium-temperature chloride solutions at a depth of 8-70,5 km. Later on, the ore-bearing fluid evolved: the concentration of carbon dioxide and the salinity of the fluid decreased. The veinlet-impregnated galena-boulangerite mineralization was formed from reduced medium-temperature light-salted solutions, probably under the low-pressure conditions. The data obtained allow us to conclude that the Antiinsky ore occurrence is a reduced intrusion-related gold deposit.
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