辽西凌源—北票断裂带有限应变分析及其意义  

FINITE STRAIN ANALYSIS OF THE LINGYUAN BEIPIAO FAULT ZONE IN WEST LIAONING PROVINCE AND ITS GEOLOGICAL SIGNIFICANCE

作　　者：王文武 武广[2] 王宏博[2] 

机构地区：[1]辽宁省化工地质勘查院,辽宁锦州121000 [2]沈阳地质矿产研究所,辽宁沈阳110033

出　　处：《地质与资源》2004年第2期75-79,102,共6页Geology and Resources

基　　金：国土资源大调查项目"华北地台北缘硫铁矿资源评价"(1999-10300101)资助.

摘　　要：凌源-北票断裂是内蒙地轴与燕山台褶带之分界断裂,对辽西大地构造格架和中新生代断陷盆地形成均具有重要作用.采用岩石有限应变测量和超微构造研究方法,恢复断裂带应变历史、计算断裂带古应力差值,研究表明:凌源-北票断裂带为拉长型应变与平面应变的过渡类型;该断裂存在两种明显不同的应变状态,NW-SE向最大主应变轴反映了燕山运动第二幕及其以前的应变状态,NE-SW向最大主应变轴反映出辽西中生代断陷盆地形成时的应变状态.通过位错密度计算出凌源-北票断裂带的古差异应力值为32.7MPa.凌源-北票断裂经历了辽河、燕辽、印支及燕山运动的叠加与改造,具有复杂的变形历史,燕山运动第二幕是本区的定格构造,奠定了凌源-北票断裂带的最终样式.Lingyuan Beipiao fault zone is an important structural zone,which makes up the boundary of Inner Mongolia geological axis and Yanshan platform folding zone.The fault controls not only geotectonic framework but also Mesozoic Cenozoic fault basins in West Liaoning.This paper reconstructs strain history of the Lingyuan Beipiao fault zone by means of three dimensional finite strain analysis,and estimates its differential paleostress.The study shows that the stress of the fault zone is an intermediate type of stretching strain and plane strain.The longest principal axis of strain had two azimuths of NW SE and NE SW,which showed that the fault had two obvious different types of strain states.The longest principal axis of strain,which was formed in the second phase of Yanshanian movement and earlier,is in NW SE azimuth.The longest principal axis of strain,formed in the period of Mesozoic fault basins,is in NE SW azimuth.The differential paleostress of the fault is 32.7 MPa,which is estimated by the density of dislocation.The fault was formed in Proterozoic,and superimposed and transformed by Liaohe,Yanliao and Indosinian movements,with a complicated history of deformation.The second phase of Yanshanian movement established the geotectonic framework of West Liaoning with the final pattern.

关 键 词：凌源-北票断裂 有限应变分析 大地构造 位错 古差异变力值 

分 类 号：P542[天文地球—构造地质学]