广西芒场矿田岩浆作用与锡成矿分析  

Magmatism and Sn Mineralization in the Mangchang Ore Field,Guangxi

作　　者：廖娟 伍静 黄文婷[1] 欧阳柳芸 陈喜连 解世雄 梁华英[1] LIAO Juan;WU Jing;HUANG Wenting;OUYANG Liuyun;CHEN Xilian;XIE Shixiong;LIANG Huaying(Key Laboratory of Mineralogy and Metallogeny,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Resources,Environment and Materials,Guangxi University,Nanning 530004,Guangxi,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,Jiangxi,China;The School of Tourism,Qinghai Minzu University,Xining 810007,Qinghai,China)

机构地区：[1]中国科学院广州地球化学研究所矿物学与成矿学重点实验室,广东广州510640 [2]中国科学院大学,北京100049 [3]广西大学资源环境与材料学院,广西南宁530004 [4]东华理工大学,核资源与环境国家重点实验室,江西南昌330013 [5]青海民族大学旅游学院,青海西宁810007

出　　处：《大地构造与成矿学》2024年第5期1030-1039,共10页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(42062007)资助。

摘　　要：广西丹池成矿带发育麻阳、芒场、大厂、北香和五圩等多个矿田,是我国重要的锡多金属成矿带。过去对丹池成矿带的研究多集中在大厂矿田,而对矿带北段岩浆作用了解不多。芒场矿田位于丹池成矿带北端,出露多条岩脉。芒场矿田热变质及矿化蚀变分带特征表明,细粒白云母花岗岩脉及下部隐伏细粒花岗岩与锡矿化关系密切。本文分析了与锡矿化关系密切的细粒白云母花岗岩脉的主量和微量元素组成、锆石U-Pb年龄以及锡多金属矿床中锡石U-Pb年龄,以探讨其成岩成矿时代及成锡花岗岩特征。芒场矿田细粒白云母花岗岩脉锆石U-Pb年龄为89.9±1.4 Ma,与锡多金属矿床锡石U-Pb年龄(88.4±1.3 Ma)基本一致,表明芒场矿田锡多金属矿床成岩成矿时代主要发生在~89 Ma。细粒白云母花岗岩脉含S型花岗岩特征矿物白云母,具高的A/CNK值(远大于1.1),表明其为S型花岗岩。细粒白云母花岗岩脉中含年龄为1350~799 Ma的继承/捕获锆石,结合其Rb、Sr、Ba等元素特征,表明其主要由元古宙富黏土质基底部分熔融形成。细粒白云母花岗岩脉的稀土元素具强烈的Eu负异常、呈现四分组效应,样品具有低的Nb/Ta和Zr/Hf值,表明岩浆发生高分异,有利于锡在岩浆中富集。细粒白云母花岗岩脉与深部细粒花岗岩相关,细粒白云母花岗岩和细粒花岗岩岩浆作用有利于锡在岩浆演化过程中富集及形成锡矿床。The Danchi metallogenic belt is an important tin-polymetallic district in Guangxi,China.The metallogenic belt consists of the Mayang,Mangchang,Dachang,Beixiang,and Wuxu ore fields from North to South.Previous studies have focused on the Dachang and Wuxu ore fields,while less work has been carried out on the Mangchang ore field.The Mangchang ore field is located in the northern part of the Danchi metallogenic belt.Several felsic igneous dykes cropped out in the ore field.The muscovite granite dyke connected the deep-seated fine grained granite.Thermal metamorphism and alteration zones around the fine-grained granite suggest that the fine-grained granite and muscovite granitic dyke are genetically linked to Sn mineralization.In order to determine the ages of mineralization and magmatism and the characteristics of the Sn-related granites in the Mangchang ore field,this study presents the zircon U-Pb age,major and trace element compositions of the fine-grained muscovite granite and cassiterite U-Pb age.The fine-grained muscovite granite has zircon LA-ICP-MS U-Pb age of 89.9±1.4 Ma with MSWD=2.1,whereas cassiterite LA-ICP-MS U-Pb dating yielded Tera-Wasserburg lower intercept age of 88.4±1.3 Ma,indicating that the magmatic activity and related Sn-polymetallic mineralization occurred at about 89 Ma in the Mangchang ore field.The fine-grained muscovite granite dyke contains muscovite,has high A/CNK of 2.63-2.88,and exhibits S-type granite evolution trends on the Rb vs.P_(2)O_(5),Rb vs.Th,and Rb vs.Y diagrams.All these features indicate that the muscovite granite dyke belongs to S-type granite.The fine-grained muscovite granitic dyke plots on the domain of clay-rich sedimentary source in the Rb/Ba vs.Rb/Sr plot,with residual zircon U-Pb age of 1520-944 Ma,suggesting that the granite was derived from partial melting of the Proterozoic clay-rich metamorphic basement.The REE tetrad effect,strong negative Eu anomaly,and low Nb/Ta and Zr/Hf ratios indicate that the fine-grained muscovite granitic dyke is highly evolved,whic

关 键 词：锆石U-Pb年龄 锡石U-Pb年龄 岩浆源区 锡多金属矿床 芒场矿田 广西 

分 类 号：P611[天文地球—矿床学] P597[天文地球—地质学]