Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

Hydrothermal lead-zinc-tin-silver mineralization of the Mentouling area, Hunan province, China, was formed as quartz veins which filled fault-related fractures within Paleozoic metasedimentary rocks. Geologic setting and K-Ar age data of sericite(93.86±1.58 Ma) indicate that ore mineralization occurred during the Late Cretaceous. Mineralization stage is divided as follows: early phase, consisting of pyrrhotite; middle phase, consisting of massive lead-zinc; and late-phase, consisting of lead-zinc-antimony. Based on fluid inclusion and stable isotope data, the early mineralization phase were formed at higher temperatures(290o ~ 360oC) than the late mineralization phase(210o ~ 250oC). Such cooling was a result of progressive meteoric water mixing, likely due to further fracturing of veins. The main deposition of lead and zinc(-tin-silver) occurred as a result of cooling at temperatures around 250o ~ 290oC. The early to middle mineralization occurred from high temperature fluid(up to 360oC) with the oxygen isotope composition of 7.4 to 3.4‰. The fluid experienced progressive meteoric water inundation toward the late mineralization(210o ~ 250oC; d18Owater = -0.9 to -4.7‰). The oxygen and hydrogen isotope data indicate the extensive evolution of hydrothermal fluids at Mentouling area, characterized by the progressive increasing influx of an isotopically less-evolved meteoric water into a deeply circulating highly-evolved meteoric water or a magmatic fluid.