粤东莲花山地区多期岩浆锆石年代学、Hf同位素组成及其成矿作用  

Zircon U-Pb Age and Hf Isotope of Multiple-Stage Magmatism and Mineralization in Lianhuashan Region,Eastern Guangdong

作　　者：范飞鹏[1] 肖惠良[1] 陈乐柱[1] 李海立[1] 刘建雄 邓中林 康丛轩[1] 林耿伟 陈凯[4] Fan Feipeng;Xiao Huiliang;Chen Lezhu;Li Haili;Liu Jianxiong;Deng Zhonglin;Kang Congxuan;Lin Gengwei;Chen Kai(Nanjing Center.China Geological Survey,Nanjing 210016,China;Guangdong Foshan Geological Bureau,Foshan 528000,Guangdong,China;Guangdong Second Geological Brigade,Shantou 515000,Guangdong,China;Ciollege of Resources and Geosciences,China University of Mining and Technology,Xuzhou 221000,Jiangsu,China)

机构地区：[1]中国地质调查局南京地质调查中心,南京210016 [2]广东省佛山地质局,广东佛山528000 [3]广东省第二地质大队,广东汕头515000 [4]中国矿业大学资源与地球科学学院,江苏徐州221000

出　　处：《吉林大学学报（地球科学版）》2020年第5期1462-1490,共29页Journal of Jilin University：Earth Science Edition

基　　金：中国地质调查局项目(12120114015701,DD20190153,DD20160037);国家重点研发计划项目(2016YFC0600210)。

摘　　要：粤东莲花山地区位于我国东南沿海火山岩发育区,是我国重要的钨金成矿远景区。通过对该地区各类花岗岩进行LA-ICP-MS锆石U-Pb定年、岩石地球化学特征、锆石Lu-Hf同位素组成和微量元素研究,结果表明:莲花山地区的岩浆活动至少存在3期,其中石英闪长玢岩形成于中侏罗世((168.0±2.2)Ma),黑云母二长花岗岩形成于早白垩世早期((137.5±1.9)Ma),石英斑岩形成于早白垩世晚期((102.0±1.5)Ma和(98.7±1.8)Ma);岩石以钙碱性铝质-强过铝质岩浆为主,石英斑岩和流纹斑岩与成矿关系密切;各类岩浆锆石的^176Lu/^177Hf值均低于0.002,176Hf/177Hf值大多数小于0.2827,εHf(t)值大多数处于-2.57~1.00之间,fLu-Hf值为-0.99^-0.95,二阶段模式年龄主要介于1.00~0.81 Ga之间,指示成岩物质来源主要来自新元古代古老下地壳变质泥岩和变质砂岩部分熔融,有少量幔源物质加入;锆石结晶温度大多处于650~750℃之间,岩石为I型花岗岩。莲花山地区不同阶段的岩浆活动和成矿作用与区域构造转换事件相关,虽缺少高精度成矿年龄对成矿时限的限制,但根据地质事实和本次研究认为该地区主要的钨金成矿时间应略晚于石英斑岩的形成时间((102.0~98.7)Ma)。Lianhuashan region is located in the continental volcanic area of the southeast coast of China,which is an important prospecting area for tungsten-gold mineralization.The authors studied the zircon U-Pb age,granite geochemistry,zircon trace elements,and Hf isotope of the newly found Mesozoic intrusive rocks in Lianhuashan region in the southeast coastal areas of China,and identified three stages magmatism:Middle Jurassic quartz diorite porphyries((168.0±2.2)Ma),early stage of Early Cretaceous biotite monzonites((137.5±1.9)Ma),and late stage of Early Cretaceous quartz porphyries((102.0±1.5)Ma and(98.7±1.8)Ma).The intrusive rocks belong to calc-alkaline,aluminous,strong-peraluminous magmatic rocks.The quartz porphyry and rhyolite porphyry are closely related to the mineralization.The ^176Lu/^177Hf values of all magmatic zircons are less than 0.002,the 176Hf/177Hf values are mostly less than 0.2827.The zircon Hf isotope values ofεHf(t)are mostly between-2.57 and 1.00,fLu-Hf values are in the range of-0.99-0.95,and their corresponding crustal model ages(TDM2)are mainly 1.00-0.81 Ga,which indicates that the source of diagenetic materials were derived from the partial melting of metamorphic mudstones and metamorphic sands of Neoproterozoic in the lower crust,and mixed with small amount of mantle material.The crystallization temperatures of zircons are mostly in the range of 650-750℃,which shows the characteristics of I-type granite.In combination with all these data,the magmatism and mineralization of Lianhuashan region are closely related to the tectonic transformation event.Although there is no high-precision metallogenic age to limit the time of metallogeny,the tungsten-gold mineralization time should be slightly later than the formation time of the quartz porphyry(ca.102.0-98.7)according to the geological facts and this study results.

关 键 词：花岗岩 LA-ICP-MS锆石U-PB定年 LU-HF同位素 成矿作用 莲花山钨金矿床 粤东莲花山地区 

分 类 号：P588.12[天文地球—岩石学] P59[天文地球—地质学]