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引用本文:徐先兵1 张岳桥2 贾 东1 舒良树1 王瑞瑞1. 华南早中生代大地构造过程[J]. 中国地质, 2009, 36(3): 573-593.
XU Xian-bing1, ZHANG Yue-qiao2, JIA Dong1, SHU Liang-shu1, WANG Rui-rui1. Early Mesozoic geotectonic processes in South China[J]. Geology in China, 2009, 36(3): 573-593(in Chinese with English abstract).
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华南早中生代大地构造过程
徐先兵1 张岳桥2 贾 东1 舒良树1 王瑞瑞11,2
1.南京大学地球科学与工程学院,江苏 南京 210093;2.中国地质科学院地质力学研究所,北京 100081
摘要:
提要:华南地区早中生代经历了强烈的构造变形和岩浆活动,构造动力体制发生了重大的转换。这个时期大地构造过程及其发生的构造动力学背景一直是地学界争议的焦点问题之一。本文在系统总结前人工作成果的基础上,论述了华南早中生代构造变形样式和岩浆活动序列,区分了印支构造事件和早燕山构造事件及其产生的地质效应。研究结果表明,印支构造事件发生于中、晚三叠世(245~225 Ma),构造运动产生的变形形迹主要表现为近东西向褶皱和冲断-推覆构造以及NE-NNE向左旋走滑韧性剪切,其动力与华南-华北板块沿秦岭—大别造山带的陆-陆碰撞和华南地块南缘古特提斯洋的俯冲增生作用有关。这次挤压构造事件导致华南东部加里东褶皱基底强烈复活,地壳重熔型花岗岩沿十万大山—云开大山—武夷山构造带和雪峰山地区分布。早侏罗世早期(205~190 Ma)在华南存在一个岩浆活动沉寂期,早侏罗世晚期(190~180 Ma)沿南岭构造带发育具有伸展特征的A型花岗岩和双峰式火山岩。起始于中侏罗世晚期(~170 Ma)的早燕山构造事件,在华南形成了宽1300 km、NE-NNE向褶皱逆冲构造系统,地壳增厚作用和壳幔相互作用导致了软弱的华夏加里东褶皱基底的再次强烈复活,诱发了强烈的岩浆活动,东南沿海地区火山弧相继出现。这期构造事件记录了东部大洋板块向华南大陆之下低角度俯冲作用过程,并主导了华南晚中生代一系列陆内构造和岩浆活动。
关键词:  早中生代  褶皱逆冲推覆构造  岩浆演化序列  构造动力体制转换  华南
DOI:
分类号:
基金项目:国家自然科学重点基金资助项目(40634022)和国家科技专项(SinoProbe-08)资助。
Early Mesozoic geotectonic processes in South China
XU Xian-bing1, ZHANG Yue-qiao2, JIA Dong1, SHU Liang-shu1, WANG Rui-rui11,2
1. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, Jiangsu, China;2. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081
Abstract:
Abstract:South China experienced intense tectonic deformation and magmatism in Early Mesozoic, which resulted in profound change of the geodynamic regime. The processes and settings of the early Mesozoic geotectonic processes have long been a subject of controversy. Based on a summarization of previous research achievements, this paper deals with tectono-sedimentary layers, Early Mesozoic tectonic deformation styles and magmatic sequence, with the purpose of distinguishing between Indosinian and early Yanshanian tectonic events as well as their geological effects. It is shown that the Indosinian tectonic event occurred in Middle-Late Triassic (245~225Ma) and was featured by nearly EW-trending fold-and-thrust belts and NE-NNE striking ductile shear zones, which were dynamically related to the Triassic collision between the South China Block and the North China Block along the Qingling-Dabie orogenic belt and also to the subduction and accretion of plaeo-Tethys oceans along the southern margin of the South China Block. The basement of the Caledonian folded zone in eastern South China was intensely rejuvenated, and crustal melting occurred particularly in the Shiwan Mountains-Yunkai Mountain-Wuyi Mountain tectonic zone and Xuefeng area. Early Jurassic (205~190 Ma) marks an era of quiescence of magmatic activity in South China, whereas late Early Jurassic (190~180 Ma) was characterized by A-type granite emplacement and bimodal volcanic activity along the WE-trending Nanling belt. Early Yanshanian tectonic event commenced around 170 Ma in late Middle Jurassic, which caused the formation of a ~1300-km-wide, NE-NNE-trending fold-and-thrust system in South China. Crustal thickening and crust-mantle interaction led to the remobilization of Cathaysian Block and induced intense magmatic activities, with the development of a volcanic arc in southeastern China. This event was related to the low angle subduction of an oceanic plate under the South China Block, which led to a subsequent series of late Mesozoic intracontinental tectonic processes and magmatic activities.
Key words:  South China  Early Mesozoic  fold- thrust belt  tectono-magmatic evolution sequence  change of tectonic regime