Dynamic features of the Tianshan orogen deduced from satellitic gravity data

作     者：楼海 王椿镛 王飞 

作者机构：Institute of Geophysics China Seismological Bureau Beijing China 

出 版 物：《Acta Seismologica Sinica(English Edition)》 (ACTA SEISMOLOGICA SINICA)

年 卷 期：2000年第13卷第5期

页      面：516-524页

核心收录：

学科分类：070904[理学-构造地质学] 0709[理学-地质学] 07[理学] 0707[理学-海洋科学] 0818[工学-地质资源与地质工程] 0708[理学-地球物理学] 0815[工学-水利工程] 0813[工学-建筑学] 0814[工学-土木工程] 0825[工学-航空宇航科学与技术] 0704[理学-天文学] 

基　　金：National 305 projection of Xinjiang Uygur Autonomous Region !(96-915-0703) Chinese Joint Seismological Science Foundation, b 

主　　题：geopotential model geoidal separation viscous stress pattern mantle convection 

摘      要：The latest geopotential model, EGM96, was employed to compute the free-air gravity anomaly, geoidal separation, the average density anomalies of the crust and the uppermost mantle, and the distribution pattern of the viscous stress exerted by mantle convection over Xinjiang and its neighboring areas. Based on these results and other data, we try to interpret the geodynamical features of the Tianshan orogen. Our research suggests that the Tianshan orogen is in a tectonic setting of compressive settling, driven by mantle convection. Under the effect of the compressive stress field, asymmetric in north-south direction, the Tianshan orogen upheaved quickly. The center of compressive stress field is in the south of the Tianshan, and the characteristic of stress field is favorable for the view point that the Tarim plat subducts beneath the Tianshan. The southern margin of the Juggar basin and the northern margin of the Tarim basin are two areas where the crust is of mass deficiency. We attribute the mass deficiency to the fact that the crust, in both the north and the south of the Tianshan is bent downwards under the compressive stress. Our research also indicates that the density distribution patterns in the deep of the eastern Tianshan are different from those in the middle and western Tianshan. It may be explained as the results from the east-west oriented distinction of the mantle convection.