吉林省西南部地区花岗岩类的构造环境

通过花岗岩类的地球化学研究,得出了本区花岗岩类形成的地质构造环境:早古生代晚期为岛弧环境,晚古生代是边(陆)缘海,中生代则为活动大陆边缘环境。这与地层地质学的结论相吻合,得到了相互印证。在不同时期,板块的运动方向是不断地变化的,相应地应力场也随其变化,与其相关的花岗岩成因类型亦有相应的变化。北西向断裂构造形成早,多阶段、长期活动,对花岗岩类的形成具有重要控制作用。

THE TECTONIC ENVIRONMENTS OF GRANITIC ROCKS IN SOUTHWESTERN JILIN PROVINCE

The goetectonic environments for granitic rocks were verified through study on geochemistry of granintic rocks in this area, i. e. late stage in early palaeozoic is referred to island arc environment, late palaeozoic, marginal sea(arc-back basin) associated closely with island arc; and the Mesozoic, marginal environments of active continent. The facts mentioned above coincide with conclusion of stratigraphical geology. Movemental direction of the plate frequently changes, and geostress varies correspondingly in different stages. The following factor plays an important control role in forming granitic rocks, i.e. early forming WN-trending fault structures, with multiple stages and long term activities.