Bi, Ag, Se, and Sb Contents in Galena as an Indicator of Zonality of Gold Occurrences of the Nizhne-Myakitsky Ore Cluster (Magadan Region)

Results of the study of galena from the Berental gold ore system of the RIRGD (reduced intrusion-related gold deposit) type associated with the similarly named granite stock in the southeastern part of the Yana–Kolyma gold belt are reported. There is a trend to change from (i) the bismuth–sulfotelluride mineralization of the apical (intra-intrusive) zone to (ii) the sulfide–sulfoarsenide mineralization of the proximal zone and (iii) the silver–polysulfide mineralization of the distal zone as moving away from the Berental intrusive massif outcrop. Galena in the bismuth–sulfotelluride ores is characterized by the bismuth geochemical specialization caused by bismuthine (Bi2S3) microinclusions. In the sulfide–sulfoarsenide type, in addition to bismuth, the presence of silver is noted. It is caused by a solid solution of matildite (AgBiS2) in galena and, less often, by acanthite (Ag2S) microinclusions in it. In some areas, it contains gold (due to uytenbogaardtite (Ag3AuS2) or native gold microinclusions). Galena in the silver–polysulfide mineral mineralization type is characterized by increased concentrations of selenium (solid solution with clausthalite (PbSe)) and/or antimony and silver (due to miargyrite (AgSbS2) microinclusions).