MINERALOGICAL AND Geochemical FEATURES OF THE LAZURNOE GOLD COPPER-POLYMETALLIC ORE OCCURRENCE (CENTRAL KAMCHATKA)
N.D. Tolstykh1, M.O. Shapovalova1, N.S. Bortnikov2
1VS Sobolev Institute of Geology and Mineralogy of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2Institute of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences, Moscow, Russia
Keywords: sulfosalt-acanthite-chalcopyrite, gold-hessite-galena associations, Se-acanthite, S-naumannite, tennantite-(Zn), (Ag,Bi,Se)-galena, matildite, porphyry-epithermal systems, Lazurnoe ore occurrence, Kamchatka
Abstract
The Lazurnoe ore occurrence, associated with the diorite-andesite volcano-plutonic association of the Khim-Kirganik ore field located in the Bystrinsky district of Kamchatka Region, is characterized by two ore associations (stages): sulfosalt-acanthite-chalcopyrite and gold-hessite-galena. The first of them, with a predominance of chalcopyrite, includes a silver sulfoselenides of the acanthite and naumannite series Ag2(S,Sе)–Ag2(Se,S); Ag,Bi,Se-bearing galena, forming partial solid solutions with matildite AgBiS2; Bi-enriched tennantite-(Zn); chalcocite Cu2S, co-crystallizing with acanthite Ag2S to form finely dispersed mixtures of them, as well as other Cu-enriched minerals: cupropearceite [Cu6As2S7][Ag9CuS4], jalpaite Ag3CuS2, stromeyerite CuAgS, and mackinstryite Ag6Cu3S4. The second gold-hessite-galena association is composed of galena PbS, sphalerite ZnS, hessite Ag2Te, native gold and silver. The geochemical specialization of the sulfosalt-acanthite-chalcopyrite association is described by the combination of elements Cu-Ag-S-Se-As-Bi, while that of the gold-hessite-galena association is described by Au-Ag-Pb(Zn)-Te-S. Each of these associations has its own mineralogical and geochemical features due to individual hydrothermal events of the ore-forming system of the Lazurnoe ore occurrence. Based on known criteria: the association of ores with subvolcanic intrusions and dikes of quartz diorite-porphyrites; the formation sequence of the identified associations (stages), the typomorphism of the identified parageneses, and the spatial relationship with the copper-porphyry ore occurrences of the Kirganik Complex – it is suggested that the Lazurnoe ore occurrence belongs to the low-temperature facies of the porphyry-epithermal system.
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