Abstract: The interpretaition of satellite images reveals distinctly the existence of 4 arcuate fault zones (the Maomaoshan-Nanhuashan-Liupanshan,Xiangshan-Tianjingshan,Yantongshan and Niushou~shan Luoshan fault zones ) at the northeastern corner of the Tibetan plateau ,as well as the existence of annular tectonics in southern Ordos. Both the kinetic features of the arcuate structures and the configuration of annular tectonics in southern Ordos are analysed to explore the origin of these fault zones. It is suggested that the subduction of India plate in NNE direction has given rise to the extrusion of the Tibetan plateau in NEE direction. As this NEE-trending extrusion is blocked by the annular tectonics in southern Ordos, 4 arcuate fault zones, converging toward Guyuan and Jingyuan towns and diverging in NWW and NW directions, are fomed at the northeastern corner of the Tibetan plateau. This condition has caused the sinistral strike slip motion along the NWW-and NNW-trending faults,and the dextral strike-slip motion along the NW-or S-N-trending faults at the diverging portion,as well as the compressional thrusting along the faults at the converging portion.

Key words: Satellite image, Syntaxis fault, Annular tectonics, Tibetan plateau, Ordos

摘要： 卫星图像分析显示,青藏高原东北隅存在非常清晰的毛毛山-南华山-六盘山、香山-天景山、烟筒山、牛首山-罗山4条弧形断裂带和南鄂尔多斯环形构造。分析了弧形构造的运动特征和南鄂尔多斯环形构造的形态,认为青藏高原东北隅弧束断裂的成因是印度板块向NNE俯冲导致青藏高原NEE向移动所产生的推挤力,受到南鄂尔多斯环形构造的阻挡,形成了4条向固原、泾原收敛,向NWW、NW方向撒开的弧束断裂。造成撒开部分NWW—NNW向断裂左旋走滑、NW—SN向断裂右旋走滑、收敛部分逆冲挤压的特征。

关键词: 卫星图像, 弧束断裂, 环形构造, 青藏高原, 鄂尔多斯