赣东北东乡铜矿侵入岩与成矿年龄的确定及意义  

Determination of Diagenetic and Metallogenic Age and Their Significance in Dongxiang Copper Deposit,Northeast Jiangxi Province,China

作　　者：蔡逸涛[1,2,3,4] 倪培[1,2,3] 王国光[1,2,3] 陈辉[1,2,3] 张洁[4] Cai Yitao Ni Pei Wang Guoguang Chen Hui Zhang Jie(State Key Laboratory for Mineral Deposits Research, Nanjing University, Nanjing 210093, China School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China Institute o f Geo Fluid Research, Nanjing University, Nanjing 210093, China Nanjing Institute of Geology and Mineral Resources, Nanjing 210016, China)

机构地区：[1]南京大学内生金属矿床成矿机制研究国家重点实验室,江苏南京210093 [2]南京大学地球科学与工程学院,江苏南京210093 [3]南京大学地质流体研究所,江苏南京210093 [4]南京地质矿产研究所,江苏南京210016

出　　处：《地球科学（中国地质大学学报）》2017年第9期1495-1507,共13页Earth Science-Journal of China University of Geosciences

基　　金：中国地质调查局项目(No.20089935);国家重点研发计划(No.2016YFC0600206)

摘　　要：对于赣东北地区东乡铜矿床的成因机制,一直存在着海西期海底喷流沉积成矿作用与燕山期岩浆热液成矿作用的成因争议,获得精确的成矿年龄是解决这一成因争议的关键.利用LA-ICP-MS技术对矿区中与矿体伴生的花岗闪长斑岩进行了锆石U-Pb同位素定年,两个花岗闪长斑岩样品的形成年龄分别为164±2Ma、160±1Ma.同时对东乡铜矿床块状硫化物矿石中的石英,开展了流体包裹体Rb-Sr同位素定年研究,获得一条等时线年龄为161.8±9.6Ma(MSDW=1.3).结合对流体包裹体以及区域成矿作用的研究,认为该年龄可以代表东乡铜矿的形成时代.这些定年结果表明,东乡铜矿的形成可能与该区燕山期花岗闪长斑岩侵入活动带来的岩浆流体成矿作用有关.The formation of the Dongxiang copper deposit has been hotly debated for the last 20 years.In particular,the origin of the Dongxiang Cu deposit was controversial,with models ranging from Hercynian SEDEX（sedimentary exhalative deposit）to Yanshanian magmatic hydrothermal origins.Accurate dating on the mineralization and associated igneous rocks is a key to solve this problem.Using Rb-Sr isochron method on quartz（fluid inclusions）samples from the massive sulfide ore,an ore formation age of 161.8±9.6Ma（MSDW=1.3）was obtained.Intrusive rocks（i.e.,granodiorite-porphyry specially related to Cu ore-forming）in Dongxiang region was also studied.The zircon U-Pb ages are 164±2Ma and 160±1Ma for granodiorite porphyry.These results indicate that the metallogenic epoch of the Dongxiang copper deposit occurred in the Yanshanian.Combined with fluid inclusion results and regional metallogeny,it is proposed that the Dongxiang copper deposit was related to magmatic hydrothermal activities associated with the Yanshanian intrusive porphyries nearby.

关 键 词：流体包裹体 RB-SR等时线 年代学 成矿年龄 东乡铜矿 矿床 

分 类 号：P597[天文地球—地球化学]