Characteristics of river terraces and formation of the Yellow River in the source region of Yellow River

Based on the systematic measurement and research, this paper considers that the terrace of the Yellow River is composed mainly of the accumulation terraces and subordinately of erosion terraces in the source region of the Yellow River, the height of the terrace is low, and the surface of the terrace is relatively flat. First-level river terraces are only developed in the segment from the source of the Yellow River to the Gyaring Lake. Second-level river terraces are developed in the segment from the outlet of the Ngoring Lake to Yellow River Township. Thirdlevel river terraces are developed in the segment from Yellow River Township to eastern Jigzhi County. Combined with ESR dating results, the authors hold that terraces of the source region of the Yellow River were formed mainly from late Middle Pleistocene to Holocene. T1 river terrace was formed about 10 kaB.P., T2 was formed from 58 kaB.P.~19 kaB.P., and T3 was formed from 161 kaB.P.~25 kaB.P. The study of river terraces has shown that the Yellow River of the source region was probably formed in late Late Pleistocene.