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雄村矿区位于西藏冈底斯斑岩铜矿带西段,目前在该矿区发现了Ⅰ、Ⅱ、Ⅲ号斑岩型铜金矿体。文章通过Ⅱ号矿体硫、铅同位素研究,获得Ⅱ号矿体金属硫化物的δ~(34)S值为-1.6‰~-0.6‰,平均值-1.30‰,总硫同位素值(δ~(34)S_(ΣS))为0.99‰,与含矿斑岩的硫同位素组成(-2.1‰~+1‰,平均0.06‰)一致,均落入幔源硫范围,表明硫主要来自岩浆。含矿斑岩和金属硫化物的铅同位素组成~(206)Pb/~(204)Pb、~(207)Pb/~(204)Pb、~(208)Pb/~(204)Pb分别为18.460~18.560、15.586~15.622、38.603~38.727和17.972~18.425、15.528~15.593、38.024~38.489,两者的铅同位素组成基本一致,变化范围小,表明两者具有相同的来源。所有样品的铅同位素μ值为9.34~9.49,显示幔源特征,综合源区判别图解认为铅主要来源于幔源,有少量俯冲沉积物加入,矿床形成于与洋壳俯冲消减作用有关的岛弧构造环境。
The Xiongcun mining area is located in the western section of the Gangdese porphyry copper belt in Tibet. At present, the porphyry type I, II and III porphyry copper-gold ore bodies have been found in this area. Through the study of sulfur and lead isotopes of No.2 orebody, the δ 34 S value of the metal sulfide of No.2 orebody is -1.6 ‰ ~ -0.6 ‰, the average value is -1.30 ‰, the total sulfur isotope value (δ ~ (34) S_ (ΣS)) is 0.99 ‰, which is consistent with the sulfur isotopic compositions of ore-bearing porphyries (-2.1 ‰ ~ + 1 ‰, average 0.06 ‰) and falls into the mantle source sulfur range, indicating that sulfur is mainly derived from magma. The Pb isotopic compositions of porphyry and metal sulfides are 206 Pb / 204 Pb, 207 Pb / 204 Pb and 208 208 Pb / 204 Pb, respectively ~ 18.560, 15.586 ~ 15.622, 38.603 ~ 38.727 and 17.972 ~ 18.425, 15.528 ~ 15.593 and 38.024 ~ 38.489, respectively. The Pb isotopic compositions of the two are basically the same with a small variation range, indicating that the two have the same source. The Pb isotopic values of all the samples ranged from 9.34 to 9.49, indicating mantle-source characteristics. According to the comprehensive source discrimination diagram, lead was mainly derived from the mantle source, and a small amount of subduction sediments were added. The deposits formed in the island arcs related to subduction and subduction of the oceanic crust Construction environment.