吉林临江地区早元古代老岭群叠加变形作用研究

早元古代老岭群经历了三期构造变形，分别形成了三个特征各异的构造形迹组合。Ⅰ世代为层理榴皱组合，由斜卧诏皱、轴面片理和韧性剪切变形带组成；Ⅱ和Ⅲ世代为片理相皱组合，分别由各种位态的片理诏皱和轴面招劈理、膝折面理组合。Ⅰ、Ⅱ世代的原始构造线方位均为近南北向，为近共轴叠加，但固Ⅲ世代构造的改造，现今多变位为北东东向。Ⅰ世代构造形迹组合的特征显示老岭群的早期构造环境具有构造层次较深、以近水平韧性剪切变形作用为主导的特点。

A STUDY OF THE SUPERIMPOSED DEFORMATION OF THE EARLIER PROTEROZOIC LAOLING GROUP IN LINJIANG AREA JILIN PROVINCE

The prepterozoic Laoling Group has undergone three phases ofdeformation and formed three generation of structure assemblages with differentcharactristics.The first generation is called as assemblage of bedding fold,composed ofrecumbent folds with axial- plane schistosity and ductile shear zones. Both of the secondand third are named as assemblages of schistosity folds,comprised of all kinds ofschistosity folds with axial- plane crenulations as well as kink structures.The first twogenerations of structure asscmblage had similar primary-structure direetion of south- north,superimposed with almost paralleling axis.However, because of the strongdeformation of thc third generation of folds,their structural directions have largely beenturned to east- west.The earlier tectonic environment implied by the characristies of theearlier structure assemblage of bedding folds is dominated by low angle,ductile sheardeformation at pretty lower structural level of the crust,and the palaeo tectonic basinextended in tho direction of S- N,paralleling to the original direction of the earlierstructure assemblages.