碰撞后的地壳尺度伸展记录——中亚造山带南缘-华北克拉通北缘深部电性结构的揭露  

Post-collisional extend record at crustal scale:Revealed by the deep electrical structure from the southern margin of the central Asian orogenic belt to the northern margin of the North China Craton

作　　者：梁宏达[1] 高锐[1] 候贺晟 李文辉[1] 韩江涛[2] 刘国兴[2] 韩松[2] 

机构地区：[1]中国地质科学院地质研究所国土资源部深部探测与地球动力学重点实验室大陆构造与动力学国家重点实验室,北京100037 [2]吉林大学地球探测科学与技术学院,长春130026

出　　处：《地质科学》2015年第2期643-652,共10页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：中国国家专项项目"深部探测技术实验与集成"(编号:SinoProbe-02);国家自然科学基金项目(编号:41430213;41474081);中国地质调查工作项目(编号:1212011220754;12120114066001)资助

摘　　要：中亚造山带作为地球上规模宏伟的造山带之一,是显生宙以来陆壳增生和伸展作用强烈的地区。华北克拉通是世界上最古老的陆块之一,晚中生代以来经历了大规模的伸展作用。中亚造山带与华北克拉通南北相连,悠久的构造演化进程使这一地区成为研究大陆造山及造山后伸展作用的理想场所。本文对新近完成的横过中亚造山带南缘一华北克拉通北缘(洪格尔-怀来)的600 km大地电磁长剖面,进行了严格规范的数据处理、分析和反演,获得了深部电性结构模型,研究了中亚造山带南缘和华北克拉通北缘深部壳幔结构,进而为该区构造演化提供新的依据。沿剖面,上地壳高阻体与分布的花岗岩对应;中、下地壳向北倾斜的高导层与其下方高导体相连,指示出地幔物质上升的通道,该套高导层与高导体可能形成于板块碰撞后的伸展环境,反映出地幔物质的上升作用是碰撞后构造伸展的主要动力。The Central Asian Orogenic Belt（CAOB）is one of the worM＇s largest accretionary orogens and it is the most representative area of crustal accretion and transformation since Phanerozoic. The North China Craton（ NCC）, the oldest craton in China, experienced intraplate tectonism that formed the Yinshan-Yanshan belt and lithospheric destruction in the Mesozoic. Both the CAOB and the NCC are research hotspots for geologists, and they are natural field laboratories to study the continental orogeny and extension after orogeny. A 600 km long magnetotelluric sounding profile from the southern margin of the CAOB to the northern margin of the NCC has been completed and an electrical structure model of the crust and the upper mantle was finally obtained after data processing, qualitative analysis and 2D inversion of the observed data. High resistivity in the upper crust of the profile may represent the large scale outcrop of granites. The north-dipping conductive layer in the middle-lower crust connected with the below conductive bodies may indicate the uptrend channel of the mantle, and they are probably formed in post orogenic extensional environment, reflecting the rising of the mantle material is the major impetus of the extension.

关 键 词：中亚造山带南缘 华北克拉通北缘 大地电磁测深 深部电性结构 伸展构造 地幔上升通道 

分 类 号：P541[天文地球—构造地质学] P319[天文地球—地质学]