桂东北泥盆纪金子岭钨矿白云母Ar-Ar年龄及其地质意义  

The Ar-Ar Age of Muscovite from Late Devonian Jinziling Tungsten Deposit in Northeast Guangxi and Its Geological Implications

作　　者：朱艺婷 李晓峰[1,2,3] 肖荣 ZHU Yi-Ting;LI Xiao-Feng;XIAO Rong(Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Institutions of Earth Science,Chinese Academy of Sciences,Beijing 100029,China;College of Earth Science,University of Chinese Academy of Sciences,Beijing 100049,China;Hunan Institute of Geological Survey,Changsha 410116,Hunan,China)

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院矿产资源研究重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学地球与行星科学学院,北京100049 [4]湖南省地质调查院,长沙410116

出　　处：《华南地质与矿产》2019年第4期423-432,共10页Geology and Mineral Resources of South China

基　　金：国家自然科学基金项目(41472080)资助

摘　　要：广西金子岭钨矿位于桂北越城岭-苗儿山复式岩基的东侧。该地区的构造-岩浆-成矿作用的演化历史可以说是华南地区地质演化的缩影。前人的研究表明该地区发育加里东期(奥陶纪、志留纪)、印支期(三叠纪)和燕山期(侏罗纪、白垩纪)花岗岩及其有关的成矿作用,但是否存在海西期岩浆活动及其有关的成矿一直没有得到证实。金子岭钨矿主要产于细粒二长花岗岩与奥陶系白洞组灰岩的接触带及二长花岗岩中。细粒二长花岗岩中发育大量的电气石+石英+白云母集合体,这些集合体是岩浆阶段向热液阶段转换过程的产物。实验选择与白钨矿密切共生的电气石石英集合体中的白云母进行Ar-Ar年代学测试。采用加权平均得到其坪年龄为372.34±2.82 Ma(MSWD=6.17),线性回归计算其等时线年龄为368.47±7.09Ma(MSWD=5.59)。结果表明,金子岭钨矿形成于晚泥盆世,是海西期岩浆-热液活动的结果。从已有的越城岭-苗儿山地区与钨矿有关的成岩成矿时代来看,该地区钨的成矿在时代上是连续的,而不同于华南南岭地区钨集中成矿的特点。南岭地区是否存在海西期花岗岩的成矿应引起足够的重视。The Jinziling tungsten deposit is located on the east side of Yuechengling-Miaoershan batholith,northeast Guangxi, China. Its geological evolutionary history can be representative tectonic-magmatic evolution of south China. Previous studies show that Caledonian(Ordovician,Silurian), Indosinian(Triassic),and Yanshanian(Jurassic, Cretaceous) granites and related mineralization occurred in this area. However, the occurrence of the Hercynian granite and its related mineralization have not been reported. The Jinziling tungsten orebody mainly occurred in the contact zone between fine-grained monzonite granite and Ordovician Baidong limestone. A large number of assemblages of tourmaline + quartz + muscovite occur as spherical or oval in fine-grained monzonite. This assemblage is usually considered the transition structure from magma to hydrothermal. In this paper,the muscovite in the tourmaline and quartz veins, which closely associated with scheelite mineralization,was selected for Ar-Ar age dating. We get the weighted plateau age of 372.34±2.82 Ma(MSWD = 6.17),and a linear regression isochron age of 368.47±7.09 Ma(MSWD = 5.59). The result shows that the Jinziling tungsten deposit was formed in the Late Devonian and was the result of magmatichydrothermal activities in Hercynian period. It is indicates tungsten mineralization in the Yuechengling-Miaoershan area is continuous in age,which is quite different from tungsten mineralization in Nanling area,where the tungsten mineralization occur as concentrating in South China.

关 键 词：金子岭钨矿床 白云母Ar-Ar年龄 海西期 桂东北 

分 类 号：P618.67[天文地球—矿床学] P597.3[天文地球—地质学]