若尔盖高原采日玛至玛曲之间的沿泽洼地,是黄河的一段古河道。白河对黄河的袭夺是形成这段古河道的直接原因.古河道的地面高度和组成物质相当于现代黄河的二级阶地,即发育于中更新世.从地貌和地层分析,古黄河在若尔盖高原曾大范围摆荡,遗留下许多宽谷治泽,蕴藏着丰富的泥炭资源。

The old channel of the Huanghe River is located to south of Maqu,Gansu, Province,72.5Km long from south to north,5-11Km wide from east to west. A vast piece of swamps developing within the old channel,presents an inverse"S"shape clearly on Landsat images.As for geomorphological type,it corresponds to the second terrace of the modern Huanghe River.The surface constituents are peat layers and fine sand with river facies,The mineral composition is similar to that of the second terrace of the modern Huanghe River near Maqu. Neotectonic movement is a basic cause of the old channel formation. Tangke was the sunsidenee center of the Ruoergai Plateau in the Pleistocene,which caused the old Huanghe River to move eastward.The capture of the Huanghe River by the Baihe River is a direct cause.The old channel developed in the middle Pleistocene.Based on the analysis of geomorphology and stratigraphy,in the Pleistocene the old Huanghe River wriggled on the Ruoergai plateau extensively.Riganqiao-Keharqiao compond valley near Waqen is a large old channel of the Huanghe River.In these old channels there are rich peat resources.