祁连山东南缘基于RGMAP的数字化地貌研究

Preliminary Digital Geomorphologic Research on Southeastern Margin of Qilian Mountains Based on RGMAP

在RGMAP平台下 ,以数字高程模型DEM为基础 ,结合野外路线调查、图切构造地貌剖面 ,较系统地研究了青藏高原东北缘祁连山东南麓 (达坂山—拉脊山 )地区典型层状地貌分布发育特征 ,初步识别出了调查区的两级夷平面 (一级夷平面海拔 30 0 0m、二级夷平面4 0 0 0m左右 )、多级山足剥蚀面 (1～ 11级 )及主要入海水系如黄河及其支流 ,如湟水河、大通河发育的河流阶地系列 ,其中湟水河发育 7级河流阶地 ,黄河 5级河流阶地 ,黄河干流于盐锅峡段贯通之前 ,湟水河一度为黄河上游源头 .结合野外调查和室内分析 ,本文详细描述了各级层状地貌分布特征、沉积学、形成时代及其与新构造运动的关联 ,说明典型层状地貌的发育是青藏高原晚新生代以来间歇性构造抬升的结果 .

The typical stratified landforms in the southeastern margin of the Qilian Mountains have been recognized and studied in detail on the basis of digital elevation model, field survey and tectonic- geomorphologic section as well as the indoor study with the support of the operation system of regional digital geological survey and field mapping (RGMAP). There are two stages of planation surfaces (P I 3 000 m, P II 4 000 m), eleven stages of pediments (Pe 1-11) and seven terraces (T 0-T 6) of the Huangshui River. Five terraces are developed in the Yellow River from the Yanguoxia to Bapanxia. Before the Yellow River mainstream passed through the Yanguoxia about 0.15 Ma, the Huangshui River used to be its upper reach. Combined with field survey and analyses indoors, every stages of stratified landforms (planation surfaces, pediments and terraces) are recognized, showing detailed features of distribution, sedimentary and formation ages and relation with neo-tectonic movements. This demonstrates that development of typical stratified landforms resulted from phased uplift of the Qinghai-Xizang plateau in Late Cenozoic.