The origin of the carbonate-hosted Huize Zn-Pb-Ag deposit, Yunnan province, SW China: constraints from the trace element and sulfur isotopic compositions of pyrite

The Huize Zn-Pb-Ag deposit in SW China has an ore reserve in excess of 5 Mt. with an ore grade of 25wt% Zn+Pb and 46-100g/t Ag. This deposit is hosted in Carboniferous dolostone and limestone. Sulfide mineralization is dominated by sphalerite, galena, and pyrite. Four types of pyrite (Py1 to Py4) are temporally and spatially related to mineralization distinguished on the basis of textural features and mineral associations. Pyrite 1 to 3 corresponds to the pyrite-sphalerite sub-stage, whereas Py4 corresponds to sphalerite-galena-pyrite sub-stage. Pyrite 1 shows zoned texture composed of an inclusion-rich core and an inclusion-free rim, whereas Py2, Py3, and Py4 show replacement relic or overgrowth textures. The zoned texture in Py1 was formed by multiple stages of ore fluids, whereas replacement relic texture in Py2 to Py4 was formed by replacement of pyrite by late Pb-Zn-rich fluids. Trace element variation in pyrite results from a combination of mineral inclusions, co-precipitating minerals, and various fluid compositions. Sphalerite, pyrite, and galena have S-34 values of 10.4-23.5 parts per thousand, suggesting that sulfur was probably derived from the thermochemical reduction of marine sulfates. The Huize pyrite has Co and Ni concentrations (0.02-9.5ppm and 0.08-143ppm, respectively) and Co/Ni ratios (0.01-2.63) similar to pyrite from sedimentary exhalative deposits, submarine hydrothermal vents, and sedimentary pyrite, which may be due to pyrite precipitation from low-temperature (