1990 Volume 40 Issue 221 Pages 175-182
The ore deposit of the Kato mine consists principally of narrow gold-silver-bearing lead-zinc veins emplaced along fissures in the Cretaceous Kanmon Group. The primary ore minerals are sphalerite, galena, pyrite, chalcopyrite, bornite and electrum. Small grains of hessite and sylvanite have been firstly found. Associated secondary minerals, covellite, brochantite and a digenite-like mineral are mineralogically described. The homogenization temperatures of liquid rich two-phase fluid inclusions in quartz range from 220°C to 290°C. Using this temperature range and the FeS content (1.1-1.7 mole%) in sphalerite, the sulfur fugacity of chalcopyrite-sphalerite-galena-pyrite assemblage is estimated to have the range of-13.1 to -8.4 on a log scale.
