延边地区前中生代主要变质岩地质演化特征概述

A PRELIMINARY STUDY ON THE EVOLUTIONARY CHARACTERISTICS OF THE PREMESOZOIC MAIN METAMORPHIC ROCKS OF THE YANBIAN AREA,JILIN PROVINCE

延边地区的主要变质岩层在前中生代时期经历了与板块构造截然不同的构造演化，即古陆裂解—汇聚拼贴—复合造山这三个发展阶段：中晚元古代古陆裂解为古亚洲海域初级发展阶段，其沉积岩层经基巴利—阿森特期构造运动发生褶皱造山，成为连接两古陆块的过渡性陆壳基底；早古生代时期，过渡性陆壳基底再次裂开，其沉积岩层经加里东构造运动，发生拼贴造山，古生代中期地壳抬升，使该区进入微大陆发展阶段；晚古生代时期，微大陆发生裂陷，该区进入古亚洲海域的未期发展阶段，于寒特—拉丁尼期完成两古陆的最后拼贴，过渡性地壳变为成熟地壳，该区与南北两古陆块一同加入统一的欧亚大陆。

n Premesozoic peroid,the main metamorphic strata of the Yanbian area displayed entirely different tectonic evolution from the plate tectonics,i.e. ancient land cracking-convergent matching-compound orogenics,1.The mid-late Proterozoic ancient land cracking is a primary developing stage in Paleo-Asian ocean space;sedimentary strata occurred as folding tectonics through the Kibaran-Assyntian orogeny,resulting in formation of intermediate continental crust basement which linked up with two ancient land plates.2. In early Paleozoic peroid,intermediate continental crust basement was cracked again,sedimentary strata occurred as matching tectonics through Caledonian orogeny,leading to crust uplifting of mid-Paleozoic crust and,entering into microcontinental developing stage.3. In late Paleozoic,faulted-depression of microcontinent occurred,entering into the end of Paleo-Asian ocean developing stage.The final matching of two ancient lands in Scythian-Ladinian periods was finished;intermediate crust was transformed into a mature one,and the two ancient land masses with a SN strike entered an unified Eurasian continent.