甘肃酒泉盆地河流地貌与新构造运动  

RESPONSE OF ALLUVIAL LANDFORMS TO NEOTECTONICS IN THE JIUQUAN BASIN, GANSU, NORTHWEST CHINA

作　　者：李有利[1] 谭利华[2] 段烽军 杨景春[1] 

机构地区：[1]北京大学城市与环境学系,北京100871 [2]北京师范大学资源与环境学系,北京100875

出　　处：《干旱区地理》2000年第4期304-309,共6页Arid Land Geography

基　　金：国家自然科学基金!(49601003和49771013)资助

摘　　要：通过对甘肃酒泉盆地北大河、洪水坝河、丰乐河、马营河的阶地进行了野外形态量计，获得了它们的阶地纵剖面，对洪水坝河的阶地年龄进行了测定和估计，并通过卫星像片解译对这些河流的洪积扇进行了制图。作者认为酒泉盆地河流阶地纵剖面的形态和洪积扇的迁移受断层控制，河流在距今大约１６万年和４万年发生的两次由加积转化为下切的事件可能代表两次构造抬升相对强烈时期。The Jiuquan Basin is a reverse- fault- controlled basin in the north west part of the Hexi Corridor, a Cenozoic foreland basin system located in the northeastern margin of the Qinghai-Tibet Plateau. From the southwest to the northeast, the landforms in the Jiuquan Basin can be divided into three zones, i. e., the North Qilian Mountain, basin plain, and North Mountain. They are parallel with the active fault zones of NWW-SEE. The basin plain is around 2000 m alove sea level in the southwest and 1500 m above sea level in the northeast, which can be subdivided into three zones, i. e., the folded zone, the deep downwarped zone and the monocline zone. The present climate in this area is continental arid. The annual precipitation is only 86 mm in the Jiuquan Basin, but in the alpine zone of the Qilian Mountain over 4000 meters above sea level it can reach over 500 mm. The meltwater from the alpine zone is an important supply to the rivers. The Beida, Hongshuiba, Fengle and Maying Rivers, rising from the Qilian Mountain flow through the Jiuquan akin from south to north, and disappear in deserts to the north. The longitudinal profiles of the rivers have been obtained based on 7-10 transverse sections on each river. The longitudinal profiles of the rivers are affected by the faults. The fault in the front of the Qilian Mountains dislocated the terraces older than the T6 terrace around 40 ha BP, and the fault at the north front of the folded zone dislocated the terraces older than the T2 terrace. The river valleys are dissected into the Pleistocene gravel to the south of the fault in the front of the Qilian Mountain. The beginning of the highest terrace (T15) development represents a transition from aggradation to degradation in this area. Based on the average dissecting rate of the Hongshuiba River, it is deduced that the T15 was formed around 160 ha BP. The rivers incised through the gravel of the older fans between the F1 and F2 faults also reveal a transition from aggradation to degradation around 40 ha BP. These t

关 键 词：河流阶地 洪积扇 新构造运动 酒泉盆地 断层活动 阶地纵剖面 

分 类 号：P931[天文地球—自然地理学]