湖南仁里稀有金属矿田206号锂辉石伟晶岩脉地球化学特征及成矿时代  

Geochemical characteristics and metallogenic age of the No.206 spodumene pegmatite vein in Renli rare metal ore field,Hunan Province

作　　者：张立平 李鹏 黄志飚 刘翔 李建康[2] 黄小强 苏俊男 周芳春 曾乐 陈虎 姜鹏飞 ZHANG LiPing;LI Peng;HUANG ZhiBiao;LIU Xiang;LI JianKang;HUANG XiaoQiang;SU JunNan;ZHOU FangChun;ZENG Le;CHEN Hu;JIANG PengFei(311 Brigade of Hunan Nuclear Geology,Changsha 410100,Hunan,China;MNR Key Laboratory of Metallogeny and Mineral Resource Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;Hunan Eco-enviromnenal Affairs Center,Changsha 410014,Hunan,China;China University of Geosciences,Beijing 100083,China)

机构地区：[1]湖南省核工业地质局三一一大队,湖南长沙410100 [2]中国地质科学院矿产资源研究所自然资源部成矿作用与资源评价重点实验室,北京100037 [3]湖南省生态环境事务中心,湖南长沙410014 [4]中国地质大学,北京100083

出　　处：《矿床地质》2021年第6期1267-1284,共18页Mineral Deposits

基　　金：科学技术部国家重点研发计划(编号:2019YFC0605202);湖南省重点领域研发计划项目资助(编号:2019SK2261);湖南省自然资源厅科研项目(编号:2018-02);湖南省地质院本级科研项目(编号:201921);湖南省核工业地质局科研基金(编号:KY2018-311-01、KY2019-311-01)联合资助。

摘　　要：湖南仁里稀有金属矿田是中国近年来新发现的一处重要的花岗伟晶岩型铌、钽、锂等稀有金属矿产地,文章针对矿田含锂伟晶岩地球化学特征、成矿时代及其与花岗岩的关系,选取传梓源锂铌钽矿床内规模最大的206号锂辉石伟晶岩脉开展地球化学和白云母Ar-Ar定年工作,并与区内其他伟晶岩、花岗岩的地球化学特征、成岩时代对比分析。传梓源206号锂辉石伟晶岩属高分异稀有金属伟晶岩,形成时代为(135.4±1.4)Ma,岩石地球化学表现为高硅、高铝、低钙、相对富碱、钙碱性及过铝质特征;稀土元素总量很低,以轻稀土元素为主;微量元素富集Cs、Rb、U、Ta、Nb、Zr、Hf,相对亏损Ba、Ti,Zr/Hf、Nb/Ta比值低且集中。幕阜山地区稀有金属成矿可分为2期:第1期稀有金属成矿时代约145 Ma,与燕山早期岩浆活动有关;第2期稀有金属成矿时代135~125 Ma,为主成矿期,该期稀有金属伟晶岩与燕山晚期的二云母二长花岗岩存在成因联系,两者为同源岩浆连续结晶分异过程中不同阶段的产物。稀有金属富集成矿经历了岩浆-热液两阶段作用,Be、Nb、Ta、Li、Rb、Cs等稀有元素的富集多发生于岩浆结晶分异晚期,热液作用使Ta、Li、Rb、Cs再次富集。The Renli rare metal ore field in Hunan Province is an important granitic pegmatite type niobium,tantalum,lithium and other rare metal ore field recently discovered in South China.Based on the geochemical characteristics and mineralization age of the Li-bearing pegmatite in the Mufushan area and its relationship with granitic parent rock,this paper takes Renli rare metal ore field as an example,selecting the No.206 spodumene pegmatite vein,which is the largest vein in the Chuanziyuan deposit,to carry out geochemical study and muscovite Ar-Ar dating,and compare the geochemical characteristics and mineralization age with other pegmatites and granites in the Mufushan area.The No.206 spodumene pegmatite vein is high differentiation rare metal pegmatite,the formation age is(135.4±1.4)Ma,which is the product of crystallization differentiation in the late magmatic stage.The geochemical characteristics of the spodumene pegmatite are characterized by high silicon,high aluminum,low calcium,relatively rich in alkali,calc alkaline and peraluminous.The content of REE in the pegmatite is very low,mainly LREE.The pegmatite is enriched in Cs,Rb,U,Ta,Nb,Zr and Hf,relatively depleted in Ba and Ti,with low and concentrated Zr/Hf and Nb/Ta ratios.The mineralization of rare metal in the Mufushan area can be divided into two stages:the age of the first stage is about 145 Ma,which is related to the early Yanshanian magmatic activity.The age of the second stage is about 135~125 Ma,which is the main mineralization stage and related to the late Yanshanian magmatic activity,the rare metal pegmatite of this period is genetically related to the two-mica monzogranite,they are the products of different stages of continuous crystallization and differentiation of the same magma.The rare metals are enriched and experienced two stages of magma andhydrothermal mineralization.During the continuous crystallization of magma,the enrichment of Be,Nb,Ta,Li,Rb,Cs and other rare metal elements mostly occurs in the late stage of magmatic crystallization di

关 键 词：地球化学 仁里矿田 锂辉石伟晶岩 白云母Ar-Ar年代学 成矿作用 传梓源锂铌钽矿床 

分 类 号：P618.6[天文地球—矿床学]