甘新蒙北山地区构造格局及演化

甘新蒙北山地区地处天山东段、北山及阿拉善地区 ,为古生代哈萨克斯坦板块、塔里木板块和华北板块交汇地带。可分为 7个二级构造单元 (构造区 )、2 6个三级构造单元 (地块、褶皱带 )。该区构造演化史漫长而复杂。太古宙时期 ,是古陆核形成萌芽阶段 ,古元古代初陆壳开始生成 ,出现薄壳结构的宽广的裂陷活动带 ,到了中、新元古代后期显露出板块构造运动 ,新元古代晚期经历重大热事件———晋宁运动 ,发生陆块间汇聚—碰撞并形成了榴辉岩—花岗岩岩浆带。震旦纪在晋宁期的拼合古陆上再一次裂解 ,经历了板块构造演化史。晚古生代 ,本区主体转入板内构造时期 ,以开合构造为主 ,花岗岩浆活动广泛发育。中、新生代进入板内造山和现今的盆山构造格局时期

FRAMEWORK AND EVOLUTION OF THE TECTONIC STRUCTURE IN BEISHAN AREA ACROSS GANSU PROVINCE,XINJIANG AUTONOMOUS REGION AND INNER MONGOLIA AUTONOMOUS REGION

The studied region, which occupies Eastern Tianshan Moutain, Beishan area and Alashan area, is the juncture area of Paleozoic Kazakstan Plate, Tarim Plate and North China Plate. It can be divided into seven grade2 structural units and, furthermore, twenty seven grade3 structural units. The area undertook the following geological evolution: Archean Era, paleocontinental nucleus was in its embryonic stage; continental crust was formed in the beginning of Early Proterozoic; At the later stage of Middle and Earlier Proterozoic Eras , plate tectonics came into appearing and an important thermal event-Jinning Movement took place at the later stage of Late Proterozoic, when eclogite-granite belt was formed by the collision between landmasses; Sinian Period, the collided landmass splitted again; It came into inner plate structural stage at Late Paleozoic and splitting-closing structural movement mainly took place and magmatic activities developed widespread; It entered into inner plate orogeny stage at Mesozoic and Cenozoic and the present basin ridge structural pattern was formed then.