关键词: 黄沙坪, 矽卡岩, 矿物学, 电子探针, 南岭, 湖南

Abstract: The Huangshaping polymetallic deposit is a skarn deposit, which lies on the northern margin of the middle Nanling tectonic belt. According to the output state of skarn, mineral assemblage and characteristics of petrography, the stage of mineralization is divided into skarn stage, retrograde alteration stage, the early and the late sulfide stage. The skarn minerals are mainly garnet, pyroxene, vesuvianite. Metallic minerals mainly include scheelite, molybdenite, magnetite, galena and sphalerite. The electron microprobe analysis(EPMA)result shows that the garnets forming in the skarn stages are mainly andraditegrossularite series and garnets vary from grossularite to andradite. The andradites commonly have zonal structure which can record the evolutionary process of physicochemical conditions. The andradite and grossularite both contain Sn, but the content of Sn in the former is higher than the latter. The pyroxenes are mainly diopsidehedenbergite series, and the content of Fe and Mn has a rising trend from the internal contact zone to the external contact zone. Mineralogical characteristics and compositional variations suggest that the property of fluid changed with two redox fluctuations at least. Skarn mineralogy characteristics is of important geological implications of W(Sn)MoBi polymetallic mineralization.

Key words: Huangshaping, skarn, mineralogy, EPMA, Nanling；Hunan