关键词: 阿尔金断裂, 构造转换, 尾端构造, 阿拉善

Abstract: The southern Alashan margin fault bundle is composed of 5 faults which strike EW, converge westward and splay eastward. Each fault of the fault bundle extends more than the 100km, controls the distribution of EW-trending Quaternary basins, and is featured with sinistral slip since the late Quaternary. The western part of the fault bundle-the Jintananshan Fault, tends to meet with the Kuantanshan Fault-the east part of the Altun Fault and has some relations to the Wenzhushan uplift in the transformation. According the spatial correlation, it is believed that the Jintananshan Fault as well as the whole fault bundle is the eastward-extending part of the Altun Fault. The special modality of the fault bundle, which spreads out eastwards, is in favor of decomposing and absorbing the slip movement, which is normal at a strike-slip fault's ends. The sinistral strike-slip movement of the fault bundle is the result of the Altun Fault extending further eastward, which might have begun between the end of the early Pleistocene and the beginning of the middle Pleistocene.

Key words: the Altun Fault, structural transformation, end structure, Alashan