滇东南老君山地区印支期成矿事件初探——以新寨锡矿床和南秧田钨矿床为例  

A tentative discussion on Indosinian ore-forming events in Laojunshan area of southeastern Yunnan:A case study of Xinzhai tin deposit and Nanyangtian tungsten deposit

作　　者：冯佳睿[1] 毛景文[1] 裴荣富[1] 李超[2] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]国家地质实验测试中心,北京100037

出　　处：《矿床地质》2011年第1期57-73,共17页Mineral Deposits

基　　金：国家自然科学重点基金(40930419)资助

摘　　要：老君山地区是滇东南多金属成矿带的重要组成部分,但对该区典型矿床精确的成矿时代和构造背景的研究较少。文章选择与锡石密切共生的金云母及与钨矿共生的辉钼矿为研究对象,分别运用40Ar-39Ar阶段加热和Re-Os同位素定年方法,对新寨锡矿床中的金云母及南秧田钨矿床中的辉钼矿进行了成矿时代的研究,获得了金云母的40Ar-39Ar同位素坪年龄,为(209.5±1.1)Ma,对应的等时线年龄为(209.0±2.2)Ma,辉钼矿的Re-Os同位素模式年龄为(209.1±3.3)～(214.1±4.3)Ma。上述测年结果提供了滇东南地区印支期成矿的信息。综合研究表明,新寨锡矿床和南秧田钨矿床形成于印支期后造山晚期或后碰撞阶段,受控于拉张-裂解的动力学背景。The Laojunshan area is an important part of the southeastern Yunnan polymetallic belt;nevertheless,the timing and tectonic setting of the typical deposits in this area were poorly constrained.In this paper,the authors present new 40Ar-39Ar dating of phlogopite closely coexisting with cassiterite ages for the Xinzhai tin deposit and Re-Os dating of three molybdenite samples separated from the Nanyangtian tungsten deposit to constrain timing and duration of the mineralization.Phlogopite from the Xinzhai tin deposit yielded an 40Ar-39Ar plateau age of（209.5±1.1）Ma and isochronal age of（209.0±2.2）Ma.The Re-Os model ages range from（209.1±3.3）Ma to（214.1±4.3）Ma.These ages provide the Indosinian metallogenic information in southeastern Yunnan.The available data and evidence suggest that the Sn and W mineralization in the Xinzhai tin deposit and the Nanyangtian tungsten deposit occurred in late post-orogenic or post-collisional stage during the Indosinian period in southern China and was controlled by a geodynamic setting of extension-cracking.

关 键 词：地球化学 40Ar-39Ar同位素年龄 Re-Os同位素定年 新寨锡矿床 南秧田钨矿床 印支期 滇东南 

分 类 号：P618.44[天文地球—矿床学] P618.67[天文地球—地质学]