雪峰造山带及邻区构造变形和构造演化研究新进展  

Progresses in the deformations and tectonic evolutions of the Xuefeng Orogenic Belt and its adjacent areas

作　　者：柏道远 钟响 贾朋远 熊雄 黄文义 姜文 

机构地区：[1]湖南省地质调查院,长沙410016

出　　处：《华南地质与矿产》2015年第4期321-343,共23页Geology and Mineral Resources of South China

基　　金：中国地质调查局"湖南1:25万武冈市和永州市幅区调修测"项目(1212011120793);中上扬子重点地区(雪峰山)构造演化及其与油气关系研究(1212011220750-02);湖南省地质系列图件编制与综合研究(1212011120125)

摘　　要：雪峰造山带位于江南造山带西南段,呈自南往北由NNE-NE-E W 向的弧形展布.笔者近几年来在区域地质调査和有关基础地质研究项目实施过程中,针对雪峰造山带及邻区构造变形和构造演化方面存在的若干地质问题进行了调查研究,取得以下主要新的认识或进展.（1）于雪峰造山带中段东部地区发现新的变形类型即大型膝褶带;造山带南段-中段在加里东期和早中生代均在NW-N W W 向挤压下发生过显著的构造变形和隆升;溆浦-靖州断裂东、西两侧分别为区域雪峰推覆构造的根带和中带,变形强度以该断裂为界东强西弱;南段-中段东部在加里东运动和早中生代构造运动中均具有背冲构造样式,但早中生代背冲构造的中轴相对加里东期向西迁移20？25km 以上.雪峰造山带北段西部也具背冲构造样式,加里东期逆冲推覆强度和隆升幅度明显大于南段-中段,暗示加里东运动区域挤压应力方向为S N 向.（2）前人于沅麻盆地东部及东侧外围地区厘定的多个“飞来峰”实为与逆冲断裂和正断裂有关的断夹块.（3）沅麻盆地中新生代经历了中三叠世晚期印支运动中区域NW- N W W 向挤压、晚三叠世-早侏罗世区域S N 向挤压、中侏罗世晚期早燕山运动中NWW-近E W 向挤压、早白垩世区域NW-S E 向伸展、晚白垩世S N 向伸展、古近纪中晚期N E 向挤压以及古近纪末-新近纪初N W 向挤压等7 期构造事件,其中多数事件在靖州盆地断裂与节理变形中同样得到反映.（4）详细的构造解析确证湘东南印支运动挤压应力方向为N W W 向、构造线走向为N N E 向,否定了近年来部分研究者提出的该地区S N 向挤压观点.（5）湘中盆地西部构造变形的运动学特征为自北西向南东逆冲,而不是前人所认为的自南东向北西逆冲;盆地西部向SE逆冲主要与雪峰造山带东缘向SE逆冲以及城步-新化岩石圈断裂向西俯冲有关.（The Xuefeng Orogenic Belt(XOB) is located in the southwestern segment of Jiangnan Orogenic Belt and shows arc trending of NNE →NE→EW from south to north. In recent years the authors studied on the geology problems of the deformations and tectonic evolutions of the Xuefeng Orogenic Belt and its adjacent areas in regional geological survey and research projects and reached the following progresses:(1) Large kink zones were discovered in the east part of the middle segment of XOB. In the southern-middle segment of XOB, there existed notable compressional deformations and uplifts with NW to NWW compression in both Caledonian movement and Early Mesozoic tectonic movements. The southern-middle segment of XOB can be divided into the eastern and western zones by the Xupu-Jingzhou Fault, and they were the root and middle zone of the Xuefeng thrust system with strong and weak deformations respectively. There existed back thrusts in both Caledonian event and Early Mesozoic tectonic events in the east zone of southern-middle XOB, however, the axis of the back thrust in the Early Mesozoic shifted about 20 to 25 km westwards. In the northern segment of XOB, there existed back-thrust structures and stronger thrusting, thickening and uplift relative to southern-middle XOB, which suggest the Caledonian regional N-S compression.(2) The so-called 'klippes' defined by previous researchers and located in the eastern basin and east periphery of the Yuanling-Mayang basin are faulted blocks with deep roots in fact and are related with the movement of thrust faults and normal faults.(3) The Yuanma basin underwent seven Meso-Cenozoic tectonic events such as regional NW to NWW compression in late Middle Trias Indosinian Movement, regional N-S compression during Late Trias-Early Jurassic, regional NWW to E-W compression in late Middle Jurassic Yanshanian Movement, regional NW-SE extension in Early Cretaceous, regional N-S extension in Late Cretaceous, regional NE compression during middle-late Paleogene and regional NW compression durin

关 键 词：雪峰造山带及邻区 构造变形 动力机制 新元古代 钦杭结合带 花岗岩 加里东运动 中生代盆地性质 

分 类 号：P548[天文地球—构造地质学]