摘要
江南造山带位于组成华南大陆的扬子地块和华夏地块之间,是揭示华南陆块演化及其动力学过程、探索该地区大规模岩浆多金属成矿作用的关键窗口。前人在构造学、岩石学和矿床学等方面取得了诸多进展,但仍对江南造山带的深部结构认识不明,导致对其定义、边界范围、形成时代及演化过程等方面长期存在争议,故亟需开展综合地球物理探测工作,为解决上述争议问题提供约束。鉴于后期构造运动对上地壳大幅改造的影响,致使对于江南造山带的深部边界存在不同认识,本文以重力数据和航磁数据为主、辅以大地电磁测深结果、并与水系沉积物地球化学资料相结合,厘定江南造山带的深部边界。综合重磁多尺度边缘检测、深部电性结构及75种元素水系沉积物地球化学数据聚类分析结果,推测钦杭结合带可能为江南造山带东南侧深部边界,并推断了江南造山带北部可能的深部边界和周缘的断裂构造。基于上述结果和认识,分析了区域构造对金、铜矿床的控制作用,认为江南造山带深部边界及深部断裂扮演了成矿系统中“导矿通道”的角色,从深大断裂形成之初就提供了铜、金等幔源成分为主的矿物质,在合适位置就位成矿;后期复杂的构造运动,使得局部位置再次活化,成矿物质重新富集迁移,在次级断裂等有利位置形成不同时代、不同类型的铜金等矿床。因此,本文基于综合地球物理探测所识别和划分的断裂构造格架,不仅可为厘定江南造山带的深部边界提供参考,也可为寻找幔源为主的金属矿床提供指示。
The Jiangnan orogenic belt,located between the Yangtze and Cathaysian blocks,is a key window to understand the evolution and dynamic process of the South China Block,and to reveal the large-scale magmatism and the accompanied metal mineral resources in this area.Predecessors have made a lot of progress in its tectonics,petrology and ore deposit science,but there are long-term disputes in its definition,boundaries,formation age and evolution process.The fundamental reason is that the deep structure is unclear,therefore,it is urgent to carry out deep exploration to provide support for dispute resolution.This paper focuses on the deep boundaries of Jiangnan orogenic belt,and detects the density and magnetism boundaries and inverses the deep electrical structure mainly by using gravity and aeromagnetic data together with supplemented magnetotelluric data.Combined with the cluster analysis results of 75 element stream sediment geochemical data,it is considered that the Qinhang junction belt is the southeast boundary of the Jiangnan orogenic belt,and the possible deep boundary in the north of the Jiangnan orogenic belt is further inferred and determined.On this basis,the fault structures around the Jiangnan orogenic belt are identified and re-determined,and the control of regional structures on gold and copper deposits is analyzed.It is considered that the deep boundaries and deep faults of the Jiangnan orogenic belt play the role of“ore guide path”in the metallogenic system,and provide minerals which dominated by mantle derived components such as copper and gold from the beginning of the formation of deep faults.The mineralization is in place at the appropriate position,and the complex tectonic movement in the later stage reactivates the local position,enriches and migrates the ore-forming materials again,and forms copper gold deposits of different ages and different types in favorable positions such as secondary faults.Therefore,the fault tectonic identified framework in this paper can also provide an indication for the exploration for mantle correlated metal deposits.
作者
严加永
吕庆田
张永谦
刘卫强
王栩
陈昌昕
徐峣
刘家豪
YAN JiaYong;L QingTian;ZHANG YongQian;LIU WeiQiang;WANG Xu;CHEN ChangXin;XU Yao;LIU JiaHao(Chinese Academy of Geological Sciences,Beijing 100037,China;China Deep Exploration Center,China Geological Survey&Chinese Academy of Geological Sciences,Beijing 100037,China;School of Geophysics and Measurement-control Technology,East China University of Technology,Nanchang 330013,China;College of Geophysics,China University of Petroleum Beijing,Beijing 102249,China)
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第2期544-558,共15页
Acta Petrologica Sinica
基金
中国地质调查项目(DD20190012、DD20221643、DD20160082)
国家自然科学基金项目(92062108、42074099、41630320)
国家重点研发计划项目(2016YFC0600201)联合资助.
关键词
江南造山带
重磁
综合地球物理
电阻率
地球化学聚类分析
成矿系统通道
Jiangnan orogenic belt
Gravity and magnetic data
Integrated geophysics
Resistivity inverted from magnetotelluric data
Geochemical cluster analysis
Pathway of mineral system
