中国西部阿祁昆地区的构造演化

THE TECTONIC EVOLUTION OF AQK AREA,WESTERN CHINA

纬向构造带产生的特定纬度带,是其构造“发生床”,在这些带上产生的构造形体(包括阶段性的全部建造和改造)是其构造“成生体”。纬向构造带有长期活动、多阶段发展的特点,其不同阶段促成不同的构造成生体。阿祁昆地区弯转多姿的构造带是秦昆系的古老成生体迁移扭变的结果,扭变的主因是青藏地块的右旋转动。

This paper expounded the tectonic problems in AQK area (the Altyn, Qilian and east Kunlun Mountain area) by analysing and contrasting all the'constructive'and 'des-tructive'events as well as by structural sieving. The tectonic development of the Alt-ynQilianshan and E. Kunlun fold belt shows that they are not independent fold belts, in the early period they didn't form independent structural systems,and they were components of Kunlun-Qinling latitudinal tectjnic system. Their present winding forms were the result of migration of crustal segments .According to the theory of formation of the latitudinal tectonic system, they were situated originally at where occu-ppied now by the E.Kunlun mountain.The formula of the spherical harmonic function delineates the occurrence of latitudinal tectonic systems at given latitudes of the earth, but the latitudinal tectonic systems do not always keep in the E-W direction and equidistances. Most of them were formed very early in earth history and were liable to change in later crustal development.The Kunlun-Qinling latitudinal system is just one of the example showing how the dextral rotation of QinghaiXizang land mass had deflected the E-W tectonic zone. Of course, the force which made Qinghai-Xizang land mass rotate was coming from the inertia force of the earth's rotation.