燕山板内造山带中段近东西向中生代右行走滑构造系统  

MESOZOIC DEXTRAL STRIKE-SLIP STRUCTURAL SYSTEM IN MIDDLE SEGMENT OF INTRAPLATE YANSHAN OROGENIC BELT, NORTHERN CHINA

作　　者：张长厚[1] 宋鸿林[1] 王根厚[1] 颜丹平[1] 孙卫华[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083

出　　处：《地球科学（中国地质大学学报）》2001年第5期464-472,共9页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金 (No .4970 2 0 34 ;No .49772 14 8) ;中国地质调查局 1:2 5万青龙县幅 ( 2 0 0 0 130 0 0 0 5 14 1)地质调查项目

摘　　要：阐述了分布于燕山板内造山带中段的近东西向中生代右行走滑构造系统的几何学与运动学特征 .指出该右行走滑断裂系统由古北口 -平泉断裂和密云 -喜峰口 -锦西断裂两条主干断裂 ,以及夹于其间的北西向张性断层和张裂脉、北东向压性断层和褶皱等共同组成 .近东西向主干断裂具有右行右列“P破裂”结构形式 ,北西向的张性断层和张裂脉则具有“T破裂”性质 .主干断裂与北东向压性断裂和褶皱构成了一幅右行走滑双重构造 (strike slipduplexes)格局 ,而不是不同期次变形的产物 .该走滑断裂系统形成于侏罗纪末—早白垩世初( 14 7～ 13 2Ma) .由于它恰好构成了位于辽西的走向北东、向南东逆冲的逆冲推覆构造系统与冀北、冀西北地区北东走向、上盘向北西逆冲的推覆构造的转换和调节部位 ,所以本文提出了一个右行走滑构造系统的统一构造模式 .在该模式中 ,辽西和冀北、冀西北同时代而运动方向相反的逆冲构造系统分别构成了近东西向右行走滑系统的断盘前缘挤压逆冲构造区 .认为形成该时期燕山板内造山带总体构造格局的区域构造作用方式是 :在总体北西 -南东向挤压的一级构造应力场作用下 ,造山带北部的块体相对于中生代华北地台为主体的块体做向东的右行运动 .从更大尺度上看 ,在华北克拉通与西伯利亚板块之间的构造?The geometry and inner structures as well as the kinematics of the east-west dextral strike-slip fault system in the middle segment of the intraplate Yanshan orogenic belt are described. The dextral strike-slip fault system is composed of east-west oriented master faults - Gubeikou-Pingquan fault zone and Miyun-Xifengkou fault zone, with the structures between them such as the northeast strike contractional faults and associate folds, northwest oriented extensional faults and dykes as well. The master east-west faults are characterized by subordinate right lateral overstep en echlon faults. While the northwest striking extensional faults and dykes are comparable to 'T fractures' expected by Riedel model. The northeast oriented contractional faults and related folds, meanwhile, are the counterparts of compressive structures in Riedel model. The combination of the master faults with the associate northeast fault and folds makes a strike-slip duplex structure. The strike-slip faults formed between later Jurassic and Early Cretaceous. Giving the temporal and spatial relationship among the east-west trending dextral strike-slip fault system and the southeast-ward thrust faulting in the eastern part and the northwestward thrust fault system in the western segment of the Yanshan belt, a unified tectonic model - dextral slip system has been established. This model leads to a renewed interpretation of the tectonic framework and evolution of the Mesozoic-Cenozoic intraplate Yanshan orogenic belt. In this model, the two thrust systems with opposite movement directions in western Liaoning and northwestern Hebei provinces are considered as the result of the compressions in the front of dextral strike-slip plates northeast and southwest of the master fault, respectively. It is reasonable to infer that the tectonic framework of the late Mesozoic intraplate Yanshan orogen is dominated by east-west dextral strike-slip faulting and related deformation. Furthermore, the intraplate Yanshan orogenic belt might be another 'extrusion t

关 键 词：走滑断裂系统 走滑双重构造 板内造山带 河北 中生代 燕山板块 

分 类 号：P542[天文地球—构造地质学] P534.5[天文地球—地质学]