常隱鑛山의 Au-Ag 鑛脈의 鑛物 共生 및 化學組成

Mineral paragenesis and chemical composition of Sangeun Au-Ag ore vein, Korea

The Sangeun ore deposit is located in a volcanic belt within the Gyeongsang Basin in south western Korea. The ore deposit is of representative epithermal Au-Ag quartz vein type developed in lapilli tuff. This paper presents the mineralization with special emphasis on mineral zoning of the deposits. Principal points are summarized as follows: (1) Four stages of mineralization are recognized based on macrostructures. From ealier to later they are stage Ⅰ(arsenopyrite-pyrite-quartz), stage Ⅱ(Au-Ag bearing Pb-Zn-quartz), stage Ⅲ(barren quartz), and stage Ⅳ(dickite-quartz). (2) Electrum principally occurs with arsenopyrite and galena in stage Ⅱ, and has chemical compositions of 72.9-67.1 Ag atom %, and has Ag/Au ratio of 2.69-2.04. (3) Sphalerite varies in its FeS content according to the mineralization stages; 22.03-18.60 mole % FeS and 1.33-0.23 mole % MnS in stage IB, 16.11-8.64 mole % FeS and 1.33-0.23 mole % MnS in stage Ⅱ. (4) Alteration zones of mineral assemblage, from the vein to the wall-rock, consist of sericite-quartz-pyrite, sericite-quartz-dickite, sericite-chlorite plagioclase respectively.