Evolution process of W−Pb−Zn mineralizing fluid: implication from the carbonate-hosted Subok deposit in the Hwanggangri mineralized district, South Korea

The evolutionary process and spatiotemporal variation of W and Pb−Zn mineralizing fluids was investigated for the Subok deposit, a representative W−Pb−Zn deposit in the Hwanggangri mineralized district (HMD) in South Korea. The deposit was emplaced in Paleozoic carbonate rocks, which were intruded by Cretaceous Muamsa granite. The paragenetic sequence is characterized by early pyrrhotite-scheelite-arsenopyrite and late arsenopyrite-sphalerite-galena assemblages. In terms of spatial distribution, pyrrhotite and scheelite were dominant in the lower part, whereas arsenopyrite mainly occurred in the upper part. The upward increasing δ 34 S H2S values of ore-bearing fluids range from 1.0 to 5.9‰, corresponding to a magmatic origin. In this deposit, according to As content of arsenopyrite, fluid inclusion, and sulfur stable isotope, the early W and late Pb−Zn mineralization was controlled by decreasing temperature (425–590 to 380–450 °C), pressure (0.54–5.13 to 0.38–3.99 kbar), and sulfur fugacity of the uprising ore-bearing fluids. In the HMD, wolframite and molybdenite mainly occur in the granitic rock, whereas scheelite is precipitated in the carbonate host rock under decreasing oxygen fugacity, salinity, and pH, and the input of Ca from the host rock in the distal area. Late Pb−Zn mineralization was achieved by decreasing temperature and pressure of ore-bearing fluids and mixing with meteoric water in the distal area. The mineral zonation and physicochemical variation of W and Pb−Zn mineralizations can be applicable as indicators for the exploration of ore deposits.