Acta Geographica Sinica ›› 2018, Vol. 73 ›› Issue (7): 1338-1352.doi: 10.11821/dlxb201807012

• Earth Surface Process • Previous Articles     Next Articles

The evolution of drainage pattern and its relation to tectonic movement in the upstream Yangtze catchment

YU Yang(),WANG Xianyan(),LI Yiquan,DAI Yan,LU Huayu   

  1. School of Geography and Ocean Science, Nanjing University, Nanjing 210023, China
  • Received:2017-08-07 Online:2018-07-25 Published:2018-07-13
  • Supported by:
    National Natural Science Foundation of China, No.41522101;National Key Research and Development Program, No.2016YFA0600500;The Fundamental Research Funds for the Central Universities, No.020914380043; Dutch-Chinese Exchange Program


The Tongtian section of the Yangtze River is located in ??the central part of the Tibetan Plateau where the neotectonic activity is illustrated by frequent earthquakes, such as the Yushu earthquake (Ms 7.1) on April 14, 2010. The study area is situated in the upstream parts of the Yellow River Basin, the Yalong River and Lanchang River catchments. In this region the tributaries have developed an inverted drainage pattern with nearly right-angle intersection. Based on terrain and areal river system analysis, including geomorphic index calculation, this paper discusses the evolution of the drainage pattern related to the neotectonic movements in this area. Two groups of valleys are distinguished with NW-SE and SW-NE directions, respectively. The NW-trending rivers are unfit channels with gentle slope and large width, while most of the SW-trending rivers are canyons with steep slope and V-shaped transect. It turns out that the steepness index (ks) in the southeastern part of the Tongtian River is higher than that in the Duocai-Ningqia basin, Dengailong basin, Yequ basin and the southwestern part of the Batang basin. The stream length-gradient index (SL) is similar in the whole catchment, but the SL values in the inverted channels and nearly right-angle intersecting channels are abnormal. The value of the hypsometric integral (HI) is over 0.45 at both sides of the Tongtian River, while it is 0.15-0.45 in the Duocai-Ningqia basin, Dengailong basin, Yequ basin and Batang basin. The values and distribution of geomorphic indexes indicate that the pre-existing SE-trending parallel-drainage pattern turned to an inverted-drainage pattern as a result of strike-slip faulting. Dangjiang, Lixing, Longbao and the northeastern part of the Shanglaxiu regions became pull-apart basins, while the tributaries of the Tongtian River in the northeast eroded dramatically headward as a result of the uplift of the NE-trending thrust, and finally captured the former SE-trending channels.

Key words: neotectonic movement, inverted drainage pattern, river capture, strike-slip fault, Tongtian River, Tibetan Plateau