西藏龙马拉多金属矿床硫、铅同位素组成及其地质意义  

Sulfur and lead isotopic compositions of Longmala Polymetallic Deposit,Tibet and its geological significance

作　　者：付强[1,2] 郑远川[2] 黄克贤[2] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中国地质科学院地质研究所,北京100037

出　　处：《有色金属（矿山部分）》2012年第4期26-30,共5页NONFERROUS METALS(Mining Section）

基　　金：国家重点基础研究发展计划(973计划)(2011CB403100);中国地质调查局地质调查项目(1212011121253);国家自然科学青年基金(41102033)

摘　　要：龙马拉矿床是冈底斯北缘Pb-Zn-Ag-Cu-Fe成矿带东侧的矽卡岩型多金属矿床。对该矿床矿石矿物进行S、Pb同位素分析表明,其金属硫化物的S同位素组成均一,δ34S为1.6‰～3.6‰,显示出岩浆硫的特征。矿石矿物206 Pb/204 Pb、207 Pb/204 Pb、208 Pb/204 Pb范围分别为18.648 8～18.657 2、15.711 2～15.716 6、39.159 9～39.176 3。Pb同位素组成变化范围较小,显示Pb同位素来源于同一岩浆源区。在Pb构造模式图上靠近上地壳演化线。龙马拉矿床的S、Pb同位素数据暗示,成矿物质主要来自上地壳,可能存在地幔源区物质的混入。Longmala deposit is located in the eastern part of the north Gangdese Pb-Zn-Ag-Cu-Fe belt. Analysis of the S and Pb isotopic compositions of ore minerals in the Longmala deposit indicates that the sulfur isotopic corn positions of metal sulfides in the deposit are relatively concentrate, with their δ^34 S values ranging from 1.6‰ to 3.6‰, showing the characteristics of mantle sulfur. The ^206 Pb/^204 Pb,^207 pb/^204 Pb and ^208 Pb/^204 Pb ratios for ore min- erals from the deposit are in the ranges of 18. 6488-18. 6572, 15. 7112-15. 7166, and 39. 1599-39. 1763 respec- tively. The Pb isotopes compositions change in a smaller range, implying that the Pb isotopes have the same origin. The date points of the Pb isotopes are mostly close to the upper crustal Pb evolution curve in the plumbotectonic model. The S and Pb isotope data of the Longmala Pb-Zn-Fe-Cu deposit indicate that the ore materials are mainly derived from the upper crust and there might be the participation of the mantle source.

关 键 词：S同位素 PB同位素 龙马拉多金属矿床 冈底斯带 西藏 

分 类 号：P632[天文地球—地质矿产勘探]