摘要
雪峰造山带位于江南造山带西南段,是研究和认识华南构造演化的重要窗口。本文在对雪峰造山带北段灰山港地区的构造变形特征系统调查的基础上,探讨了构造变形体制、成因机制和加里东运动及印支运动构造线方向横向变化的成因。调查发现,区内存在两个角度不整合面,据此划分3个构造层,即加里东构造层(Nh~S_(1))、海西-印支构造层(D_(2)~P)和晚燕山-喜山构造层(K_(2)~E_(2))。不同构造层主要变形式样包括:加里东构造层中近EW向褶皱及同走向逆断裂、板状劈理等;海西-印支构造层中NEE向褶皱及同走向逆断裂、NW-NNW向断裂(走滑为主)、节理(包含共轭节理)和劈理等;晚燕山-喜山构造层中NE向宽缓褶皱、控盆断裂以及不同方位与性质的小断裂等。根据构造层的变形特征、断裂构造的衍生次序和构造变形的主应力方位,结合区域构造演化背景,识别出7期构造变形事件,初步厘定了研究区早古生代以来的构造体制演化过程。结合前人资料提出:加里东构造层变形受深部多层次拆离滑脱控制,海西-印支构造层变形则受控于盖层沿下伏不整合面及二叠系龙潭组的滑脱;雪峰造山带及邻区加里东运动、印支运动构造线走向均存在自南往北,总体上由NNE向→NE向→NEE向→EW向的变化特征,分别形成于华南各地块碰撞拼贴、华南与华北和印支板块汇聚碰撞的地球动力学背景,并受新元古代扬子-华夏结合带边界或继发性陆内俯冲制约。
The Xuefeng orogenic belt,located in the southwestern Jiangnan Orogen,is an important subject to study the tectonic evolution in South China.In this paper,the tectonic deformation in the northern Xuefeng Orogen is investigated systematically,and then the tectonic deformation mechanism and lateral variation of the Caledonian and Indosinian tectonic lines are studied.Three tectonic layers separated by the two angular unconformities in this region can be recognized,i.e.,the Caledonian(Nh-S_(1)),Hercynian-Indosinian(D_(2)-P)and Late Yanshan-Xishan(K_(2)-E_(2))layers.Among them,the Caledonian layer has nearly EW-trending folds,synclinal reverse faults and plate cleavage;the Hercynian-Indosinian layer is dominated by the NE-NNE-trending folds,synclinal reverse faults,NW-NNW-trending faults(mainly strike-slip),joints(including conjugate joints)and cleavage;while the Yanshanian-Xishanian layer has NE open folds,basin-controlling faults and small faults with different orientations and properties.According to the deformation of the tectonic layers,the order of some faults and principal stress orientation of structure deformation,as well as the regional tectonic background,seven tectonic deformation events were identified and the tectonic system evolution process since the early Paleozoic in the study area was preliminarily determined.Based on the structural analysis and previous data,it is considered that the deformation of the Caledonian layer is controlled by the deep multi-level detachment,while that of the Hercynian-Indosinian layer is subjected to the detachment of the cover along the unconformity surface and the Permian Longtan Formation.From the south to the north,the trend of the Caledonian and Indosinian tectonic lines in the Xuefeng structural belt and its adjacent areas generally change from NNE,through NE and NEE,to EW.They were respectively formed by the assembly of different blocks in South China,the collision between the South China Block and the North China and Indosinian plates,as well as the influences fr
作者
李彬
许德如
柏道远
钟响
李银敏
高成
曾广乾
邹光均
凌跃新
LI Bin;XU Deru;BAI Daoyuan;ZHONG Xiang;LI Yinmin;GAO Cheng;ZENG Guangqian;ZOU Guangjun;LING Yuexin(State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,Jiangxi,China;Hunan Institute of Geological Survey,Changsha 410016,Hunan,China;Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China)
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2022年第1期1-21,共21页
Geotectonica et Metallogenia
基金
中国地质调查局地质矿产调查项目(DD20160031-04)
国家自然科学基金重点项目(41930428)
湖南省地质院科研项目(2019-17)联合资助。
关键词
雪峰造山带
灰山港地区
褶皱
断裂
构造格架
变形期次
构造背景
Xuefeng Orogen
Huishangang area
fold
fault
structural framework
deformation sequences
tectonic setting
