Formation conditions of noble metal mineralization in sulfide cobalt-copper-nickel ores of Kamchatka (on the example of Annabergitovaya Schel ore occurrence)

The authors present research results, the purpose of which is to study the specifics of noble metal mineralization and its genesis in sulfide cobalt-copper-nickel ores of the Kamchatka nickel-bearing province. The paper is dedicated to one of its many ore occurrences called Annabergitovaya Schel (Annabergite Gap). The material composition of platinoid, silver, gold, bismuth and tellurium minerals, as well as sulfarsenides in the ores of this occurrence was investigated. Based on the data of mineral formation sequence and the use of geosensors, conclusions were drawn regarding the genesis of noble metal mineralization. Formation of platinoid minerals, silver and gold at the Annabergitovaya Schel ore occurrence is mainly associated with the epigenetic effect of post-ore granitoids on ore-bearing intrusion rocks of the Dukuk complex of the cortlandite-norite formation and on syngenetic ores. An early association of noble metal minerals is represented by sperrylite, irarsite, and rare unnamed phases of Pt + Ir + Te. Irarsite and Pt + Ir + Te phases were formed at the contact-metasomatic stage. Sperrylite can be assumed to be of magmatic origin. Silver sulfides and tellurides, silver and palladium bismuth tellurides, and native gold were formed at the late, hydrothermal-metasomatic, stage. The occurrence conditions of mineral parageneses, associated with noble metal mineralization, correspond to the formation of shallow-depth metasomatic rocks (5 km). Sub-developed quartz-feldspar metasomatites, associated with the formation of early platinoid arsenides and sulfarsenides, are in equilibrium with circumneutral solutions (pH of 4.5-6.5) at temperatures of 350-600 °C. Late hydrothermal association with Pd, Ag and Au minerals is close to propylites and was formed at pH values of 4.5-6.5 and temperature of 150-350 °C.

SILICATE, IRON OXIDE AND COPPER-GOLD-SILVER MICROSPHERULES IN ORES AND PYROCLASTICS OF THE KOSTENGINSKOYE IRON ORE DEPOSIT (RUSSIAN FAR EAST)

Iron-oxide ores and pyroclastics from the Kostenginskoye deposit in the Malyi Khingan (Russian Far East) contain numerous silicate, iron-oxide, and copper-gold-silver microspherules. Silicate spherules are composed of immiscible iron- and silica-rich glasses, gas cavities and mineral inclusions. Iron-oxide spherules include magnetite with minor ilmenite and Fe-rich silicate glass. Copper-gold-silver spherules contain inclusions predominantly of copper oxide compositions. The studied microspherules are considered to have formed during the rapid ascent of metal-silicate melts from depth and their degassing controlled by liquid immiscibility differentiation. The paper discusses the possible volcanic origin of iron-oxide ores and the associated noble metal mineralization for the deposits of this type.

Noble metal mineralization in apatite titanomagnetite ores of the Suroyam massif (Middle Urals)

The mineralogical composition of apatite-titanomagnetite clinopyroxenites of the Suroyam massif, characterized by stable elevated contents of platinum group elements with the leading role of palladium, has been studied. In association with accessory chalcopyrite, palladium and silver minerals have been identified – mertieite, merenskyite, hessite. It has been suggested that the presence of intrinsic mineral phases of palladium, represented by tellurides and arsenides-antimonides, allows us to consider the Suroyam massif as a promising deposit of complex Pd-P-Fe ores.

Gold in ash and slag material of the Primorsk hydroelectric power

The paper shows the results of studies on the identification of noble-metal mineralization in various components of ash and slag formations: underburning, aluminosilicate microspheres, initial ash (fed to the magnetic separation of the technological section of Primorsk SDPP), magnetic and non-magnetic fractions – using analytical and mineralogical methods, electronic microscopy. An integrated approach made it possible to reliably establish significant concentrations of gold, to identify the factors of technological persistence of anthropogenic materials. All products contain free gold grains ranging in size from 50 to 230 micrometers and microscopic inclusions of 0.5-20 microns. The content of free grains of gold is from 0.4 to 1.37 mg / kg. The gold is pure or with an admixture of silver (up to 17% of the mass). Depending on the research materials, gold contains variable inclusions of magnetite, ilmenite, quartz, glass, amphiboles, pyroxenes, clay minerals, and carbonaceous formations. Gold grains have complex structure and morphology. Micronized inclusions, usually rounded, also contain an admixture of silver.

Genesis of noble metal mineralization (Ag, Au, PGE) on the example of pechenga structure (Kola peninsula)

The problem of the genesis of noble metal (Ag, Au, PGE) mineralization in the Norther Pechenga zone is discussed, where these ores are associated with the classical Cu-Ni deposits of Pechenga Ore Field. This mineralization is based on three main factors: subalkaline magmatism under conditions of compression, feeding of platform depressions with carbonaceous matter and basalt-silica splitting of magmas under conditions of liquid immiscibility. Considered geochemical aspects of this process. Briefly characterized vein deposits of noble metals in the Souther Pechenga zone. The purpose of the article. The purpose of the article is to draw the attention of geologists to a possibly wide range of deposits of noble metals and diamonds, the genesis of which is associated with basalt-silica splitting under conditions of liquid immiscibility. Eruptive breccias of such deposits are often described by geologists as terrigenous rocks and conglomerates.