赣南柯树岭岩体锆石U-Pb年龄、岩石地球化学及成矿作用特征  

Zircon U-Pb age,petro-geochemical and mineralization characteristics of Keshuling granites in southern Jiangxi Province

作　　者：李伟 刘翠辉 谭友 陈伟[1] 鲁捷 尹积扬 陈再威 LI Wei;LIU Cuihui;TAN You;CHEN Wei;LU Jie;YIN Jiyang;CHEN Zaiwei(Geological Survey Team of Gannan,Bureau of Geology of Jiangxi Province,Ganzhou,Jiangxi,341000)

机构地区：[1]江西省地质局赣南地质调查大队,江西赣州341000

出　　处：《地质论评》2021年第5期1309-1320,共12页Geological Review

基　　金：中国地质调查局地质调查项目“江西崇义柯树岭—赣县合龙锡多金属矿集区矿产地质调查”(编号:DD20190166-12、DD20190166-2020-08)的成果。

摘　　要：青山钨锡矿床位于南岭成矿带东段的九龙脑钨锡矿田内,石英脉型矿体主要产于柯树岭岩体外接触带。利用LA-ICP-MS锆石U-Pb定年方法测得花岗岩年龄为228.7~233.4 Ma,谐和年龄为231.0±0.63 Ma(MSDW=0.77),成岩时代属印支期。柯树岭花岗岩属过铝质高钾钙碱性岩石系列,岩石表现出高Si、高K、高Al和低Mg、低P、低Ti;富集成矿元素W、Sn,亏损Sr、Ba、Ti、Eu等微量元素的特征;岩石稀土元素总量低,轻重稀土元素分馏明显,配分曲线为右倾型。岩体的岩浆物质主要来源于地壳,成岩机制主要为后碰撞期或碰撞晚期的被动侵入。青山矿床具有一定的分带性,石英脉型矿体自上而下可划分为:细脉—中脉混合带(上部)和大脉带(中下部),少部分矿体延伸至岩体内。青山钨锡矿床成矿作用发生于印支期,全矿Sn矿化富集明显,推测九龙脑矿田北部存在有较大规模的印支期Sn成矿作用。Objectives:The Qingshan tungsten—tin deposit is a quartz-vein type ore deposit in the Jiulongnao tungsten—tin orefield.The study of Keshuling granites in this deposit not only helps to understand the features of metallogenic geological body,but also can provide evidences for the Indosinian mineralization.Methods:Detail geological survey,LA-ICP-MS zircon U-Pb dating of medium—fine two-mica granite,whole rock geochemical of biotite granite and two-mica granite in Qingshan deposit.Results:The zircon U-Pb dating of Keshuling granite yields emplacement age of 231.0±0.63 Ma (MSDW=0.77),belongs to the product of Indosinian magmatic activities.The whole-rock geochemical analyses show that Keshuling granite has the features of peraluminous,high-K and calc-alkali category,integrated with enrichments of Si O_(2),Al_(2)O_(3),K2O,W,Sn,LREE,depletions of MgO,P_(2)O_(5),Ti O_(2),Sr,Ba,Ti,REE and Eu negative anomaly.Qingshan deposit is rich in tin mine and the orebody can divided into the thin—wide mix vein(upper part) and wide vein (middle and lower part),and little thin—huge vein in granite body.Conclusions:Keshuling granite is formed in the middle Triassic (228~233 Ma).According to the geochemical characteristics,Keshuling granite were mainly formethed by parital melting of crustal sedimentary rocks in the post-collision period or late stage of syn-orogenic tectonic setting.Qingshan deposit is characterized by"two levels"without"basement"of quartz-vein orebodies,and significant rich in tin.

关 键 词：锆石U-PB年龄 岩石地球化学 成矿作用 柯树岭岩体 印支期 赣南 

分 类 号：P611[天文地球—矿床学] P59[天文地球—地质学]