青藏高原腹地东西分区和界带的地球物理场特征与动力学响应

Geophysical field characteristics and dynamic response of segmentations in East-west direction and their boundary zone in central Tibetan plateau

青藏高原是东亚大陆一个特殊的块体,无论是介质属性,还是构造格局在深部与浅部都是不均匀的和各向异性的,其演化进程也是非线性的.基于综合地球物理场研究发现:青藏高原在NS向挤压和EW向扩张错综力系作用下,形成了东、西分区的构造格局,它们的界带位于900±20E的范围内,即表明青藏高原基本上为由三块(西、中、东)组成.在此界带与其东、西两侧的重力场、地磁场、地热场、地震波场、深部介质与结构和其物质组成的属性均存在着显著差异,表征出分区(界)的特异深层过程和动力学响应.

Tibetan Plateau is a special block of Eastern Asia, whose medium properties and tectonic patterns are inhomogeneous and anisotropic. Moreover its evolution process is nonlinear. The compound geophysical fields indicate that Tibetan plateau is divided into eastern and western subareas by complicated force system that compress in NS direction and expand in EW direction. Their boundary is around the rang of 90°±2°E. It means that Tibet is composed of three parts （west, middle and east）. In the middle zone, the gravity field, geomagnetism field, geothermal field , seismology field, properties of deep medium and structure and its composition are quite different from the eastern and western parts, which indicate that the deep process and dynamical response are different in the whole plateau.