This paper is the result of mineral exploration engineering.
Objective The Huangshaping Cu-Sn polymetallic deposit is one of the typical representatives of the magmatic hydrothermal metallogenic system in southern Hunan, China. In order to deepen the diagenetic and metallogenic mechanism of the deposit and efficiently guide the exploration of deep prospecting, it is necessary to reveal the polymetallic mineralization-alteration zone rule related to the concealed granite porphyry, and construct the deep mineralization-alteration spatial zoning model.
Methods Applying the large-scale altered lithofacies location prospecting and prediction method for hydrothermal deposits, and the geochemical analysis of rock and mineral for tunnel sections in the typical levels of -136 m, -176 m and -256 m, the intensity change of mineralization-alteration, mineral paragenetic association and its spatial zoning characteristics were analyzed, and the transformation rules of ore-forming elements, element associations and element ratios were discussed.
Results The current study constructed mineralization-alteration zoning model: from porphyry (internal zone) to contact zone to surrounding rock (outer zone) with scheelite-molybdenite (pyrite) mineralized-silicified-sericitized granite porphyry zone (Ⅰ) → magnetization (scheelite-cassiterite) mineralized garnet skarn zone (Ⅱ-1) → scheelite-molybdenite-pyrrhotite mineralized garnet skarn zone (Ⅱ-2) → lead-zinc mineralized crystalline limestone zone (Ⅲ) → strong calcitization limestone zone (Ⅳ). The main mineral assemblages of in the corresponding zones are: Quartz + (Pyrite + Sericite) → Magnetite + Diopside + Wollastonite + Epidote + Chlorite + (Scheelite + Cassiterite + Pyrite + Garnet) → Scheelite + Molybdenite + Pyrrhotite + (Cassiterite + Chalcopyrite + Pyrite + Sphalerite + Galena) + Garnet + Vesuvianite + Diopside + Hornblende + Fluorite + Epidote + Chlorite + (Quartz + Calcite) → Galena + Sphalerite + (Pyrite) + Calcite + Quartz → Calcite + Quartz. The distribution rule of mineralized elements in each alteration zone was revealed: W, Mo → Fe, W, Sn (Bi, Mo) → W, Sn, Bi, Mo (Cu) → Pb, Zn (W, Sn, Cu) → Pb, Zn, Ag.
Conclusions The mineralization-alteration zoning rule of the deposit was obvious from the rock mass as the center to the surrounding rock on both sides. The transformation rules of characteristic mineral assemblage and mineralization indicator elements in each zone have an obvious indication of the occurrence position of the ore body.