Multiple metal sources in polymetallic W-Sn ore deposits revealed by mercury stable isotopes  

作　　者：Zhendong TIAN Bernd LEHMANN Changzhou DENG Xingchun ZHANG Anbo LUO Yinghua CHEN Runsheng YIN 

机构地区：[1]State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China [2]Mineral Resources,Technical University of Clausthal,Clausthal-Zellerfeld 38678,Germany [3]Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming 650093,China

出　　处：《Science China Earth Sciences》2024年第11期3465-3475,共11页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 41873047, 42102277);the China Postdoctoral Science Foundation (Grant No. 2021M703188);the Guizhou Provincial 2021 Science and Technology Subsidies (Grant No. GZ2021SIG)。

摘　　要：Granite-related W-Sn ore systems are commonly associated with coeval Pb-Zn mineralization. It remains unclear whether these metals are derived from the same sources or not. Mercury(Hg) is a common minor component in such systems. Hg isotopes undergo unique mass-independent fractionation(expressed as Δ^(199)Hg values), which is mainly generated during Hg photochemical reactions on Earth's surface and not affected by magmatic-hydrothermal processes, offering an excellent opportunity to trace metal sources in hydrothermal systems. We observed near-zero Δ^(199)Hg values in wolframite(-0.10‰ to0.08‰, n=11), and in skarn-(-0.17‰ to 0.12‰, n=48) and greisen-type(-0.12‰ to 0.10‰, n=11) bulk tin-tungsten ore from eight major ore deposits in South China. These values are identical to those of coeval highly evolved granites(-0.13‰ to 0.12‰,n=49), supporting that Hg in W-Sn ores were sourced from granite. However, sulfides(e.g., pyrite, chalcopyrite, arsenopyrite,galena, and sphalerite) in these deposits exhibit negative to near-zero Δ^(199)Hg values(-0.42‰ to 0.09‰, n=124), which indicates a contribution of Hg and by inference other metals from both Precambrian basement rocks(Δ^(199)Hg<0) and ore-related granites.The study demonstrates that multiple sources of metals were involved in the formation of the polymetallic W-Sn deposits, and further highlights that extraction of metals from basement rocks may be a critical control on the formation of economically important mineralization of base metal sulfides(e.g., Pb, Zn) in granite-related magmatic-hydrothermal systems.

关 键 词：Tin-tungsten deposit Mercury isotope Metal source Metal zonation South China 

分 类 号：P618.2[天文地球—矿床学]