The Jinsan gold mine, Korea : a mineralogical and geochemical study

The Cretaceous Jinsan gold-bearing hydrothermal veins occur within the Late Proterozoic to Mid Ordovician metasedimentary rocks, intruded by Early Cretaceous pink-feldspar granite(142±2.0 m.y.). Electrum-galena-sphalerite mineralization was deposited in three stages of quartz and calcite veins. Quartz sulfide-bearing stage Ⅰ and Ⅱ evolved from initial high temperatures (near 360℃) to later lower temperatures(near 220℃) from lower salinity fluids(1.0 to 3.2 wt.% NaCl eq.). Fluid inclusion data from the post ore carbonate stage reflects much cooler(110° to 180℃). Evidence of boiling indicates pressure of ＜85 bars, corresponding to depths of 400m to 1050m assuming lithostatic and hydrostatic loads. Au-deposition was likely a result of boiling, coupled with declining temperatures. The δ³⁴S H₂S values calculated for sulfides are consistent with an igneous source of sulfur with a δ³⁴S∑S value near 4.0‰.