扬子西南缘大红山铁铜多金属矿床矿化方解石脉方解石Sm-Nd定年及意义  

Sm-Nd isotopic dating of calcite in the ore-bearing calcite vein from the Dahongshan iron copper polymetallic deposit in the southwestern margin of Yangtze block and its significance

作　　者：金廷福 罗伟 李佑国[3] 李朋威[4] 孙腾蛟[3] 兰叶芳 JIN Ting-fu;LUO Wei;LI You-guo;LI Peng-wei;SUN Teng-jiao;LAN Ye-fang(Guizhou University of Engineering Science,Bijie 551700,Chian;Zunyi Normal University,Zunyi 563006,China;Chengdu University of Technology,Chengdu 610059,China;Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083,China)

机构地区：[1]贵州工程应用技术学院,贵州毕节551700 [2]遵义师范学院,贵州遵义563006 [3]成都理工大学,四川成都610059 [4]中国石化勘探开发研究院,北京100083

出　　处：《矿物学报》2021年第3期343-354,共12页Acta Mineralogica Sinica

基　　金：毕节市科学技术项目(编号:毕科合字[2019]22号);中国地质地调局项目(编号:12120113094900);遵义师范学院博士基金项目(编号:遵师BS[2020]5号);贵州省教育厅青年人才项目(编号:黔教合KY字[2020]146);贵州省科技合作计划项目(编号:黔科合LH字[2017]7017,[2016]7050,[2015]7590)。

摘　　要：扬子西南缘是我国重要的铁铜金矿产资源产区,分布许多铁铜多金属矿床,而本次研究的大红山矿床属扬子西南缘内最大的铁铜多金属矿床之一。铁、铜矿化方解石脉中方解石测年结果表明,Sm-Nd等时线年龄为(818±3) Ma,代表方解石脉中磁铁矿、黄铜矿矿化年龄为818 Ma。结合扬子西南缘成岩成矿关系、背景研究,揭示该矿化事件与Rodinia超大陆裂解期大陆裂谷环境有关。据方解石Sm-Nd同位素体系中(143Nd/144Nd)i值0.5112649和εNd(t=818 Ma)值范围介于-6.3~-6.2之间的组成特点,指示方解石中Nd为壳幔混源,且以幔源为主。The southwestern margin of Yangtze block,known as the Kangdian copper metallogenic belt,is an important production area of iron-copper polymetallic resources in China,as there are many small-large iron-copper polymetallic deposits.The Dahongshan deposit which is studied in this study is one of the biggest iron-copper polymetallic deposits in the southwestern Yangtze block.The dating results of calcites in Fe-Cu-mineralized calcite veins indicate that the Sm-Nd isochron age of 818±3 Ma represents the mineralization age of magnetite and chalcopyrite in calcite veins.Combined with researches on the relationship and background of diagenesis and metallogenesis of the southwestern margin of Yangtze block,it is suggested that the mineralization event could be related to continental rift environment in the breakup period of Rodinia supercontinent.Based on compositional characteristics of the Sm-Nd isotope system of calcites including the(143Nd/144Nd)i value of 0.5112649 and εNd(t=818 Ma) values ranging from-6.3 to-6.2,it is indicated that the Nd in calcite could be from a mixed source of crust and mantle,with majority of the mantle source.

关 键 词：SM-ND等时线年龄 方解石 大红山铁铜多金属矿床 扬子西南缘 

分 类 号：P597.3[天文地球—地球化学] P618.2[天文地球—地质学]