内蒙古大青山北公益明—高家村逆冲型韧性变形带特征及其地质意义

Geological features and significance of thrust ductile deformation belt of Gongyiming-Gaojiacun at Northern Daqingshan in Inner Mongolia

公益明—高家村韧性变形带发育太古代花岗绿岩带与高级区接触带附近,在空间上呈近东西方向展布,是由北向南逆冲型韧性变形带。该韧性变形带遭受两期韧性变形作用改造,早期发生在地壳深部构造层次上角闪岩相条件下,以韧性变形机制为主。晚期变形作用发生地壳中浅部构造层次上,以韧脆性变形作用为主。韧性变形带内主要构造岩为构造片岩,是以新生的片状、纤状矿物为主的构造岩。宏观与微观不对称流动组构表明,韧性变形带运动方向为由北向南逆冲。韧性挤压逆冲变形作用发生太古代晚期,是由北部花岗绿岩带与南部高级区相互拼贴碰撞有关。

Gongyiming-Gaojiacun ductile deformation belt is located in near the contact zone of the Archean granite greenstone belt and high-grade metamorphic rock,in space nearly EW direction,being thrust ductile deformation belt from north to south.The ductile belt was modified by two deformation phases,the early deformationwhich was mainly ductile deformation mechanism,took place in the conditions of amphibolite facies of deep crustal tectonic levels.The late deformation one,which was mainly ductile-brittle deformation mechanism,took place in middle-shallow tectonic level of the crust.In ductile deformation belt,the main tectonite is the tectonic schist,which was consist of new flaky minerals and fibrous minerals.The macrograph and micrograph asymmetrical flow fabrics shows that movement direction of ductile deformation belt was thrusting from north to south.The ductile compression thrust deformation took place in late Archean,being relate to the collision between the northern granite greenstone belt and the southern high-grade metamorphic rock.