| Figure 6 The formation model of the terrace in Huangshui catchment (modified after Wang et al., 2010). Firstly, the fluvial balance state is crossed because of climatic change or tectonic and the river incisions, until reaching to a new balance state; Secondly, the tectonic subsidence happens in the blocks, and an intensified erosion in upstream while a huge volume of sediments supplied deposit quickly in the subsidence depression. Finally, the river incises in the whole catchment, caused by climatic changes such as increasing of the precipitation and the reducing of the sediment load caused by the relevant development of the vegetation cover or tectonic uplift, and the accumulation terraces are formed in the subsidence depressions while the erosion terraces or no terrace are formed in upstream blocks. |
