榆木山地貌指数及活动构造意义

he mountain range of the Yumu Shan is located in the front of the actively growing mountain range of the Qilian Shan, which ex-tends NW-SE for more than 600 km at the northeastern margin of the Tibetan Plateau. The Yumu Shan is the topographic expression of an actively growing fault-propagation fold developed in the hanging walls of a system of mostly northeast-vergent buried reverse faults which has not yet broken the Quaternary surface. The tectonic activity is relatively strong within the yumushan block since the Cenozoic, and successivly become younger from south to north, gradually weakened their strength and size. We calculated stream-length gradient (SL), hypsometric curve (HI), asymmetry factor (AF), and found that there are significant differences between the northern and southern mountain. SL changes mainly reflect tectonic activity change information in Yumu Shan, and SLk analysis showed a strong correlation between the abnormal Z-score and fault distribution. The contrary distribution of AF in northern and southern Yumu Shan corresponds to Yumu Shan anticline whose formation is related to the northern Qilian Mountain buried reverse faults. Hypsometric curve analysis and HI values shows the differences between northern and southern mountain, the erosional stage of the cathment in northern slope is younger than in southern, and suffered relatively weaker erosion than southern due to the strong tectonic activity of faults since the Cenozoic, correspondes to the result of developing of the buried reverse fault.