广西王社铜钨矿床的Re-Os同位素年龄及其地质意义  

Re-Os Isotopic Age of Molybdenite from the Wangshe Copper-Tungsten Deposit in Guangxi Province and Their Implications

作　　者：蔺志永[1,2] 王登红[1] 李水如 

机构地区：[1]中国地质科学院矿产资源研究所,国土资源部成矿作用与资源评价重点实验室,北京100037 [2]中国地质调查局,北京100037 [3]广西地质调查总院,南宁530031

出　　处：《地质学报》2008年第11期1565-1571,共7页Acta Geologica Sinica

基　　金：国家科技支撑计划课题(编号2006BAB01B03);中国地质大调查项目(编号1212010633903和1212010634002);危机矿山接替资源勘查计划(编号200545022)等项目资助的成果

摘　　要：广西王社铜钨矿床主要类型是斑岩铜钼矿,叠加有石英脉型黑钨矿,Cu、Mo和W都可利用,其中Cu的平均品位在0.3%以上。本文利用ICP-MS测试技术获得高精度的辉钼矿Re-Os同位素年龄值,结果表明,王社铜钨矿化模式年龄为94.9～96.3Ma,等时线年龄93.8±4.6Ma,属燕山晚期。与成矿有关的昆仑关岩体主体岩性是黑云母花岗岩,被后期花岗斑岩脉穿插,岩石地球化学特征显示黑云母花岗岩SiO2含量68.6%～72.1%,花岗斑岩脉为73.8%;Al2O3含量前者为14.16%～14.75%,后者14.07%;全碱含量前者6.78%～8.15%,后者8.1%;且均显示出K2O>Na2O的特征。初步推断该成矿带燕山晚期的成岩成矿动力学背景为岩石圈伸展。Wangshe Cu-W deposit, located in Guangxi province, is a porphyry type copper and molybdnium deposit, superimposed by quartz vein-type tungsten. Cu, Mo and W in the deposit are economic elements with an average Cu grade of more than 0.3%. The molybdenite Re-Os age is 94. 9-96.3 Ma with an isochron age of 93. 8 ± 4. 6Ma （n = 6） by ICP-MS method, suggesting an age of late Yanshanian. Kunlunguan batholith related to mineralization is dominated by biotite granite cut by later granitic porphyry dykes. Lithological and geochemical analysis shows that the former is 68.6%-72.1% in SiO2, and Al2O3 in 14. 16%-14.75% and the latter is 73.8% in SiO2 and Al2O3 in 14.07%. The total alkaline content of the former is 6.78%-8.15%, and that of the latter is 8. 1%, both characterized by K2O〉 Na2O. It is preliminarily inferred that the geodynamic setting of Late Yanshanian mineralization in this region is lower crustal delarnination and lithospheric thinning.

关 键 词：RE-OS同位素年龄 岩石地球化学 王社铜钨矿床 昆仑关岩体 

分 类 号：P597[天文地球—地球化学]