Xijitan Landslide in Guide Basin in the Upper Reaches of the Yellow Riverand its Dammed Lakes

摘要

In the upper reaches of the Yellow River in the northeastern Tibetan Plateau, the uplift of the Tibetan Plateau and the erosion of the Yellow river reformed the landscape of the region and built steep slopes and terraces. A lot of giant landslides developed along the steep valley of the river. However, the influence of landslides to river terraces has been unclear because landslides development stages cannot be identified easily in field survey. In the study, the Xijitan giant landslide was analyzed by combining the remote sense analysis of geological facies and the field survey. The five development stages of the landslide and the related dammed lake were identified by analyzing the topographic features. It was concluded (1) the main Xijitan landslide was triggered by rain during the warm and wet Holocene Optimum period after ~6000 a BP. (2) The outburst of the dammed lake of the landslide reformed the dammed body to build a local terrace that is different from other regional river terraces.