西藏谢通门县雄村斑岩型铜金矿集区Ⅱ号矿体中辉钼矿Re-Os年代学及地质意义  

Re-Os DATING OF MOLYBDENITE FROM OREBODY NO.Ⅱ OF THE XIONGCUN PORPHYRY COPPER-GOLD METALLOGENIC DISTRICT,XIETONGMEN,TIBET AND ITS GEOLOGICAL SIGNIFICANCE

作　　者：郎兴海[1,2] 唐菊兴[3] 陈毓川[3] 李志军[1,2] 黄勇[1,2] 王成辉[3] 陈渊 张丽[4] 

机构地区：[1]成都理工大学,四川成都610059 [2]西藏天圆矿业资源开发有限公司,西藏日喀则857000 [3]中国地质科学院矿产资源研究所,北京100037 [4]中国地质调查局成都地质调查中心,四川成都610081

出　　处：《矿物岩石》2010年第4期55-61,共7页Mineralogy and Petrology

基　　金：国家基础研究计划“印度-亚洲大陆主碰撞带成矿作用”973项目(编号2002CB412607);国家科技支撑项目(编号2006BAB01A01;天圆公司青藏专项(编号1212010818089)

摘　　要：西藏谢通门雄村斑岩型铜金矿雄村铜金矿集区由Ⅰ,Ⅱ,Ⅲ号3个铜金矿体组成。针对雄村铜金矿区Ⅱ号矿体的年代学研究结果表明Ⅱ号矿体中7件辉钼矿样品的Re-Os模式年龄范围非常一致,其变化范围为169.5Ma±2.6Ma～173.6Ma±2.5Ma,结合等时线年龄[181Ma±19Ma(MSWD=4.6)]和平均模式年龄[172.6Ma±2.1Ma(MSWD=3.4)]认为最有可能的形成年龄应为172.6Ma±2.1Ma,该年龄代表雄村Ⅱ号矿体的成矿年龄,说明矿床形成于中侏罗世,属燕山早期的成矿作用。根据辉钼矿中Re的含量推测,雄村Ⅱ号矿体的成矿物质来源可能具有幔源的特点,其成矿时代与Ⅰ号矿体(161.5Ma±2.7Ma)相近,形成的构造背景亦与Ⅰ号矿体相似,即新特提斯洋俯冲阶段的岛弧环境。综合整个冈底斯带的成矿年龄可分为3个部分:161Ma～173Ma,40Ma～51Ma和12Ma～21Ma,分别对应于新特提斯洋俯冲阶段的成矿作用、印度-亚洲板块主碰撞汇聚阶段和后碰撞伸展阶段的成矿作用。The Xiongcun porphyry copper-gold metallogenic district is located in the middle of the southern margin of Gangdise orogenic belt,with its south margin as Shigatse fore-arc basin.Latest exploration data indicate that Xiongcun porphyry copper-gold metallogenic district is composed of 3 ore bodies.The study of Re-Os model age of the ore body No.Ⅱ from molybdenit（7 samples）shows that it ranges from 169.5 Ma±2.6 Ma to 173.6 Ma±2.5 Ma,its isochron age is 181 Ma±19 Ma（MSWD=4.6）with big error,and its weight average model age is 172.6 Ma±2.1 Ma（MSWD=3.4）with a small error.It reveals that the ore forming age of ore body No.Ⅱ is 169.5 Ma±2.6 Ma^173.6 Ma±2.5 Ma of Jurassic period.This age represents the mineralization age of Xiongcun ore body No.Ⅱ.Since the dating age of Xiongcun ore body No.Ⅱ is similar to that of Xiongcun ore body No.Ⅰ（161.5 Ma±2.7 Ma）,they could be formed under the same tectonic setting of island-arc environment during the northward subduction of Neo-Tethys Ocean.The content of element Re from the molybdenite shows that the ore-forming materials may come from mantle sources.On the current research situation,the ore forming age of Gangdisi metallogenic belt can be divided into three parts：161 Ma^173 Ma,40 Ma^51 Ma and 12 Ma^21 Ma,corresponding to mineralization during subduction setting of the Neo-Tethys Ocean,mineralization during the collisional orogenic setting of India plate with Asian plate and the mineralization during post-collisional extension setting.

关 键 词：Re-Os年代学 辉钼矿 斑岩型铜金矿床 雄村 西藏 

分 类 号：P597.3[天文地球—地球化学]