Sediment storage and morphology of the Yalu Tsangpo valley due to uneven uplift of the Himalaya

Abstract

The fluvial process of the Yalu Tsangpo River occurs concurrently with the uplift of the Qinghai-Tibet Plateau. Therefore, the river exhibits unique features in morphology and sediment deposition. Field investigations were performed from 2009–2011 and the depth of the interface between the sediment deposits and bed rock was detected with an electromagnetic imaging system (EH4) at 29 cross sections. Sediment deposits were sampled along the Yalu Tsangpo valley from Xietongmen to the Yalu Tsangpo Canyon. The results show that a huge amount of sediment has been deposited in four wide valley sections because the uplift rate in these sections was lower than that in the downstream gorge sections over the past million years. About 518 billion m3 of gravel and sand have been stored in the high mountain river valleys, which has changed the V-shaped mountain river valley into a U-shaped wide river valley in the four sections. In the sections with high uplift rates the river bed is incised and has formed gorges and the Yalu Tsangpo Canyon.