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SILVER MINERALIZATION OF THE KHOROGOCHI MOTHER LODE (STANOVAYA GRANITE-GREENSTONE AREA, UPPER AMUR REGION)

P. P. Safronov 1, N. V. Moiseenko 2

1 Far East Geological Institute FEB RAS, Vladivostok, Russia; 2 Institute of Geology and Natural Management FEB RAS, Blagoveshchensk, Russia.

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.

Keywords: native silver, silver sulphide, silver sulphosalts, fahl ore.

DOI 10.20403/2078-0575-2022-1-80-91

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