Vertical zoning patterns and magmatic-hydrothermal evolution of the Geumseong Mo deposit, South Korea

The Geumseong Mo deposit, South Korea, formed in the Palaeozoic sedimentary rocks following the emplacement of the Cretaceous leucocratic intrusions, representing the apical part of relatively shallow-level plutons. The Geumseong deposit comprises two kinds of ore bodies with different styles of mineralization, which include the Mo skarn deposit and the Mo-bearing aplitic cupola. The Geumseong skarns are both calcic and magnesian, but calcic ones are most common. Some aplitic cupolas are geochemically highly evolved, and have well-developed comb quartz and aplitic layers. The vertical scale alteration patterns of the deposit in the mine show Mo-bearing aplitic apical zone with proximal Fe skarn through transitional Mo skarn to distal haematite zone. The ore-bearing fluids migrated from the relatively deep contact zone of the hidden cupolas to the upper carbonate wall rocks to form different types of skarn and mineralization under physical conditions of decreasing temperature and oxidation state.