长江中下游地区铜地球化学块体时间属性——来自碎屑锆石LA-ICP-MS U-Pb定年的证据  

Temporal Distribution of Copper Geochemical Blocks in the Middle–Lower Yangtze River Region:Evidence from Detrital Zircon LA-ICP-MS U-Pb Dating

作　　者：刘彬 王学求[2,3] 侯青叶[4] LIU Bin;WANG Xue-qiu;HOU Qing-ye(Hebei GEO University,Shijiazhuang,Hebei 050031;Key Laboratory of Geochemical Exploration,Ministry of Natural Resources,Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang,Hebei 065000;UNESCO International Centre on Global-scale Geochemistry,Langfang,Hebei 065000;School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083)

机构地区：[1]河北地质大学,河北石家庄050031 [2]自然资源部地球化学探测重点实验室,中国地质科学院地球物理地球化学勘查研究所,河北廊坊065000 [3]联合国教科文组织全球尺度地球化学国际研究中心,河北廊坊065000 [4]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地球学报》2020年第6期835-850,共16页Acta Geoscientica Sinica

基　　金：河北地质大学博士科研启动项目(编号:BQ2019058);国家重点研发计划项目“穿透性勘查地球化学技术”(编号:2016YFC0600600)和“覆盖区地球化学异常源示踪与判别”(编号:2016YFC0600604);中国地质调查局地质调查项目“化学地球”大科学计划-“全球地球化学填图”(编号:121201108000150005)联合资助

摘　　要：利用水系沉积物地球化学组合数据在长江中下游地区共圈定出6个铜地球化学块体,首次利用碎屑锆石LA-ICP-MS U-Pb定年技术对地球化学块体的时间属性进行了研究。在铜矿床最为发育的Cu1、Cu2和Cu6三个块体内的碎屑锆石样品中清楚地识别出4个年龄峰值,分别对应古元古代、新元古代、早古生代和中生代。表明地球化学块体是跨时代存在的,物质来源于多期地质事件。新元古代和中生代地质体对研究区铜地球化学块体的形成也具有重要影响。研究还发现,成矿物质经后期的风化分散作用会进入到水系沉积物中,通过水系沉积物采样能够捕获成矿信息。A total of six copper geochemical blocks in the Middle–Lower Yangtze River region were delineated on the basis of composite stream sediment geochemical data.The detrital zircon LA-ICP-MS U-Pb dating technique was used to study the temporal properties of geochemical blocks for the first time.Four age peaks were identified in detrital zircon samples sampled in Cu1,Cu2 and Cu6 geochemical blocks,corresponding to Paleoproterozoic,Neoproterozoic,Early Paleozoic,and Mesozoic,respectively.The authors have reached the conclusion that geochemical blocks exist across the time,and substances in the range of geochemical blocks came from multiple geological events.It is believed that Neoproterozoic and Mesozoic geological bodies had important influence on the formation of copper geochemical blocks.It is shown that the ore-forming materials might have been transported into stream sediments through later weathering and dispersion.Mineralization information could be extracted by sampling stream sediments.

关 键 词：长江中下游 铜地球化学块体 碎屑锆石 LA-ICP-MS锆石U-PB定年 

分 类 号：P597.2[天文地球—地球化学]