雪峰山基底隆升带及其邻区印支期陆内构造特征与成因  

Features and Causes of Indosinian Intracontinental Structures in the Xuefengshan Precambrian Basement and Its Neighboring Regions

作　　者：李三忠[1] 王涛[1] 金宠[2] 戴黎明[1] 刘鑫[1] 周小军[3] 王岳军[4] 张国伟[5] 

机构地区：[1]中国海洋大学海洋地球科学学院,山东青岛266100 [2]浙江大学建筑工程学院,杭州310012 [3]西南石油大学资源与环境学院,成都610500 [4]中国科学院广州地球化学研究所,广州510640 [5]西北大学地质学系,西安710069

出　　处：《吉林大学学报（地球科学版）》2011年第1期93-105,共13页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41072152);中国石化总公司重大科技攻关项目(YPH08004)

摘　　要：狭义的华南陆块东部包括扬子地块和华夏地块,而雪峰山陆内构造系统是扬子地块的重要组成部分。通过对雪峰山地区印支期地层角度不整合时空分布规律的分析表明,高角度不整合—微角度不整合—平行不整合—整合的空间分布区域依次由东往西递变渐新。根据褶皱变形分析得出,雪峰山地区在印支期发育了北东东向和北北东向2个轴迹方向的褶皱,后期叠加了南北向弧形逆冲推覆构造。区域构造背景和动力学分析表明,扬子地块内部印支期总体北东向的变形形迹与东西轴向的秦岭—大别造山带和扬子地块南部东西轴向的构造线相垂直;其原因是:扬子地块与华夏地块最终陆内收缩变形的时间比扬子与华北沿秦岭—大别造山带的陆间碰撞拼合的时间早,印支早期的先存北北东向构造线在印支晚期由于扬子地块顺时针旋转变位为北东东向,从而决定了印支早期现今北东东向的构造线,随后的第二幕北北东向构造线的形成是在与早期第一幕变形的应力场相同的同一构造应力场作用下形成的。但是,秦岭—大别造山带近东西向的构造线取决于主动大陆边缘,即总体近东西向的华北陆块南缘边界,其原始方位为总体近东西向。这些复杂边界条件和旋转决定了先形成彼此近于垂直的构造线,然后拼接形成现今构造线垂直的格局。The eastern South China continental block can be subdivided into the Yangtze block and the Cathaycian block.The Xuefengshan intracontinental tectonic system is one important part of the Yangtze block.The distribution of the unconformities between Triassic and Jurassic in the Xuefengshan tectonic system reveals four kinds of contact interfaces,including high-angle unconformity,low-angle unconformity,disconformity and conformity and becoming younger and younger to the west.Then the characteristics of Indosinian folds are also subdivided into two directions of fold axial traces in the South China,i.e.northeast-and northwest-striking folds,which were superimposed by the N-S-trending thrusts.The authors proposed that the longitudinal arcuate and northeastward structures in the Xuefengshan intracontiental tectonic system result from a control of different block borders under the same stress field as the previous one.The first-generation NEE-striking folds are rotated from the earlier NNE-striking folds due to late block rotating.The second-generation NNE-striking folds superimpose the NEE-striking folds.The intracontinental shortening between the Yangtze and Cathaysian blocks was earlier than the collision of the South China block with the Qinling-Dabie micro-continent.The Yangtze block and the Qinling-Dabie micro-continent had rotated in Early Indosinian orogeny.these resulted in a difference between those earlier structural lines formed in Early Triassic,the perpendicular relation to these structural lines was at last remained although they underwent small rotation between the Yangtze and Cathaysian blocks.

关 键 词：印支运动 三叠纪 华南 角度不整合 扬子地块 构造地质学 

分 类 号：P542[天文地球—构造地质学]