Located on the western Yangtze Block, the Sichuan （四川）-Yunnan （云南）-Guizhou （贵州） （SYG） Pb-Zn metallogenic province has been a major source of base metals for China. In the south- eastern SYG province, str...Located on the western Yangtze Block, the Sichuan （四川）-Yunnan （云南）-Guizhou （贵州） （SYG） Pb-Zn metallogenic province has been a major source of base metals for China. In the south- eastern SYG province, structures are well developed and strictly control about 100 Pb-Zn deposits. Al- most all the deposits are hosted in Devonian to Permian carbonate rocks. Lead-zinc ores occur either as veinlets or disseminations in dolomitic rocks with massive and disseminated textures. Ore minerals are composed of pyrite, sphalerite and galena, and gangue minerals are calcite and dolomite. Sulfide min- erals from four typical Pb-Zn deposits are analyzed for sulfur isotope compositions to trace the origin and evolution of hydrothermal fluids. The results show that 034S values of sulfide minerals range from ＋3.50%0 to ＋20.26%0, with a broad peak in ＋10%0 to ＋16%0, unlike mantle-derived sulfur （0±3%0）. How- ever, the mean δ34Ssulflde and δ34S∑s-fluids values are similar to that of sulfate-bearing evaporites in the host rocks （gypsum： -＋15%0 and barite： ＋22%0 to ＋28%0） and Cambrian to Permian seawater sulfate （＋15%0 to ＋35%0）. This suggests that reduced sulfur in hydrothermal fluids was likely derived from evaporates in the host rocks by thermo-chemical sulfate reduction （TSR）. Calculated δ34S∑s-fluids values of the Shanshulin （杉树林）, Qingshan （青山）, Shaojiwan （筲箕湾） and Tianqiao （天桥） Pb-Zn deposits are ＋21.59‰, ＋18.33‰, ＋11.4‰ and ＋10.62‰, respectively, indicating sulfur-bearing hydrothermal fluids may be evolved from the Shanshulin to Qingshan and then the Shaojiwan to Tianqiao deposition sites along the Yadu （垭都）-Ziyun （紫云） lithospheric fracture in the southeastern SYG province.展开更多
基金supported by the National Natural Science Foundation of China(Nos.41102055,41272111 and 41102053)
文摘Located on the western Yangtze Block, the Sichuan （四川）-Yunnan （云南）-Guizhou （贵州） （SYG） Pb-Zn metallogenic province has been a major source of base metals for China. In the south- eastern SYG province, structures are well developed and strictly control about 100 Pb-Zn deposits. Al- most all the deposits are hosted in Devonian to Permian carbonate rocks. Lead-zinc ores occur either as veinlets or disseminations in dolomitic rocks with massive and disseminated textures. Ore minerals are composed of pyrite, sphalerite and galena, and gangue minerals are calcite and dolomite. Sulfide min- erals from four typical Pb-Zn deposits are analyzed for sulfur isotope compositions to trace the origin and evolution of hydrothermal fluids. The results show that 034S values of sulfide minerals range from ＋3.50%0 to ＋20.26%0, with a broad peak in ＋10%0 to ＋16%0, unlike mantle-derived sulfur （0±3%0）. How- ever, the mean δ34Ssulflde and δ34S∑s-fluids values are similar to that of sulfate-bearing evaporites in the host rocks （gypsum： -＋15%0 and barite： ＋22%0 to ＋28%0） and Cambrian to Permian seawater sulfate （＋15%0 to ＋35%0）. This suggests that reduced sulfur in hydrothermal fluids was likely derived from evaporates in the host rocks by thermo-chemical sulfate reduction （TSR）. Calculated δ34S∑s-fluids values of the Shanshulin （杉树林）, Qingshan （青山）, Shaojiwan （筲箕湾） and Tianqiao （天桥） Pb-Zn deposits are ＋21.59‰, ＋18.33‰, ＋11.4‰ and ＋10.62‰, respectively, indicating sulfur-bearing hydrothermal fluids may be evolved from the Shanshulin to Qingshan and then the Shaojiwan to Tianqiao deposition sites along the Yadu （垭都）-Ziyun （紫云） lithospheric fracture in the southeastern SYG province.
