基于ASTER-GDEM数据的亚东-谷露和错那-沃卡裂谷系地区构造地貌分析

Tectonic Geomorphological Analysis of Yadong-Gulu and Cona-Oiga Rift System Based on ASTER-GDEM Data

基于ASTER GDEM数据运用ArcGIS技术对藏东南地区进行高程、地势起伏度、坡度、条带剖面和面积-高程积分值(hypsometry index,HI)等数字地貌分析,结合前人资料分析藏南东部区域地质地貌特征。区内表现出西高东低和南高北低的地貌格局,米拉山地垒影响拉萨河和尼洋河的发育,沃卡地堑促进雅鲁藏布江向东发育。HI变化能反映出构造活动和岩相差异,米拉山地垒和念青唐古拉演化阶段进入幼年期(HI>0.6)是构造活动因素主导,壮年期(0.35<HI<0.60)多分布河道两岸和裂谷系两侧,河湖与裂谷系处(0.35<HI<0.43)演化为老年期阶段与冰川和河流剥蚀作用有关,外流区裂谷系及河湖盆地发育导致HI比内流区高。结果表明:研究区数字高程模型和真实地貌相吻合,亚东-谷露和错那-沃卡裂谷系的展布对研究区地貌格局划分起着重要作用。

Based on Aster GDEM data,ArcGIS technology was used to analyze the digital landform of southeast Tibet,such as elevation,topographic relief,slope,strip profile,and area elevation index hypsometry index(HI).Combined with previous data,the regional geological and geomorphic characteristics of eastern Tibet were analyzed.The analysis show that the geomorphic pattern of west high and east low and south high and north low in the area.Mira mountain Horst affects the development of Lhasa River and Niyang River,and Woka graben promotes the weastward development of Yarlung Zangbo River.HI variation can reflect tectonic activities and lithofacies differences.The evolution stage of Mira mountain Horst and Nyainqentanglha enter the juvenile stage(HI>0.6),which is dominated by tectonic activities.In the adult stage(0.35<HI<0.60),it is mostly distributed on both banks of river channels and both sides of the rift system.Rivers,lakes,and rift system(0.35<HI<0.43)evolve into the senile stage,which is related to Glacier and river denudation.The development of rift system and river lake basin in the outflow area lead to higher HI than that in the inflow area.The results show that the digital elevation model of the study area is consistent with the real landform.The distribution of the Yadong-Gulu and Cona-Oiga rift system plays an important role in the division of geomorphic patterns in the study area.