钦杭结合带南段钦州‒灵山构造带中生代板内变形特征与构造转换  

Characteristics of Mesozoic Intraplate Deformation and Tectonic Transformation in Qinzhou-Lingshan Structural Zone of the Southern Qinzhou-Hangzhou Junction Belt

作　　者：李帅[1] 汪帆 汪劲草[1] 李细光 潘黎黎 黄冠文 LI Shuai;WANG Fan;WANG Jincao;LI Xiguang;PAN Lili;HUANG Guanwen(Guilin University of Technology,School of Earth Science,Guilin 541004,Guangxi,China;Institute of Seismology,China Earthquake Administration,Wuhan 430071,Hubei,China;Earthquake Administration of the Guangxi Zhuang Autonomous Region,Nanning 530022,Guangxi,China;School of Earth Science and Engineering,Sun Yat-sen University,Zhuhai 519082,Guangdong,China)

机构地区：[1]桂林理工大学地球科学学院,广西桂林541004 [2]中国地震局地震研究所,湖北武汉430071 [3]广西壮族自治区地震局,广西南宁530022 [4]中山大学地球科学与工程学院,广东珠海519082

出　　处：《大地构造与成矿学》2023年第3期523-534,共12页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(41172089、41674075);广西科学研究与技术开发计划项目(桂科AB18126040)联合资助。

摘　　要：钦州‒灵山构造带位于钦杭结合带南段,是华南中生代形成的大型构造‒岩浆活动带。构造解析表明,钦州‒灵山构造带灵山段由走滑构造、逆冲推覆构造以及一系列伸展构造组成:早期,该段整体表现为逆‒平移性质,平面上呈一组平行或分支复合的断裂束,剖面上表现为向深部会聚的正花状构造;中期,构造带南东侧的六万大山花岗岩体逆冲推覆至古生代地层之上,其平面上呈向北西凸起的弧形复合断裂束,剖面上由前、后缘推覆型韧性剪切带及花岗岩断夹块组成的逆冲推覆构造;晚期,钦州‒灵山构造带由挤压‒推覆变形转入后造山伸展变形,沿乐民‒寨圩一带发育了张性岩墙群、伸展型韧性剪切带及大型张性断裂带。带内构造变形特征、转换及演化机制揭示:在晚古生代钦廉‒罗定裂陷槽关闭的地质背景下,扬子地块与华夏地块于中生代沿钦州‒灵山构造带灵山段发生斜向拼合‒板内造山作用。上述认识对理解钦廉‒罗定裂陷槽的闭合、扬子地块与华夏地块的分界与拼合过程、华南板内造山的动力学机制及演化、六万大山印支期花岗岩基的侵位机制、十万大山盆地的性质,皆具有重要的地质意义。The Qinzhou-Lingshan structural zone located in the southern part of the Qinzhou-Hangzhou junction belt in South China,is a large tectonic-magmatic active belt formed in Mesozoic.Structural analysis shows that the Lingshan section of the Qinzhou-Lingshan structural zone is a combination of strike slip structure,thrust nappe structure and a series of extensional structure.In the early stage,the Qinzhou-Lingshan structural zone has both strike slip and thrust characteristics,showing a group of parallel or branch composite strike slip faults on the plane,and a positive flower structure converging to the deep on the profile.In the middle stage,the Qinzhou-Lingshan structural zone overthrust the Liuwandashan granite body onto the autochthonous Paleozoic strata,showing an northwestward arc-shaped composite fault on the plane,and a thrust nappe structure composed of the front and back margin nappe type ductile shear zone and Lenticular granite fault block on the profile.In the late stage,the Qinzhou-Lingshan structural zone changed from compression-thrust deformation to post-orogenic extensional deformation,during which the tensional dike swarms,the extensional ductile shear zone,and the large tensional fault zone developed.The characteristics,transformation and evolution mechanism of the tectonic deformation in the zone reveal that under the geological background of the closure of the Qinlian-Luoding Aulacogen in the late Paleozoic,the Yangtze block and the Cathaysian block underwent oblique amalgamation-intraplate orogeny along the Lingshan section of the Qinzhou-Lingshan structural zone in the Mesozoic.The above understanding has important geological significance for understanding the closure of the Qinlian-Luoding Aulacogen,the demarcation and amalgamation process of the Yangtze block and the Cathaysian block,the dynamic mechanism and evolution of intraplate orogeny in South China,the tectonic emplacement of the Liuwandashan Indosinian granitic batholith,and the nature of the Shiwandashan Basin.

关 键 词：钦州‒灵山构造带 正花状构造 逆冲推覆构造 伸展构造 斜向拼合‒板内造山作用 

分 类 号：P542[天文地球—构造地质学]