Acta Geographica Sinica ›› 2020, Vol. 75 ›› Issue (5): 1095-1105.doi: 10.11821/dlxb202005015

• Climate Change and Surface Process • Previous Articles    

Terraces development and their implications for valley evolution of the Jinsha River from Qiaojia to Menggu

LIU Fenliang1, GAO Hongshan2(), LI Zongmeng3, PAN Baotian2, SU Huai4   

  1. 1.Department of Geographic Information System Science, Hunan City University, Yiyang 413000, Hunan, China
    2.Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
    3.School of Geographic Sciences, Xinyang Normal University, Xinyang 464000, Henan, China
    4.College of Tourism and Geography Sciences, Yunnan Normal University, Kunming 650500, China
  • Received:2019-11-12 Revised:2020-02-27 Online:2020-05-25 Published:2020-07-25
  • Contact: GAO Hongshan
  • Supported by:
    National Natural Science Foundation of China(41730637);National Natural Science Foundation of China(41901007);The Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0205)


The valley evolution of the Jinsha River is a research hotspot in the geomorphology, but there is a big dispute on the formation time and the evolution process of the river valley. Fluvial terraces and the correlative sediments contain abundant information about the fluvial valley evolution. Through field investigation combined with Optically Stimulated Luminescence (OSL) and Electron Spin Resonance (ESR) dating, we confirmed that 8 fluvial strath terraces were formed, and then preserved, along the course of the Jinsha River near Hulukou. The formation ages of T6-T1 are 1190±154 ka, 1079±118 ka, 942±92 ka, 816±48 ka, 544±82 ka, and 41±5 ka, respectively, corresponding well with the transition period of MIS. Near the Qinggangba, 5 terraces (T5-T1) composed of the dammed lake sediments are preserved on the hillslope, with ages of 629 ka, 88 ka, 71 ka, 49 ka and 20 ka, respectively, indicating that the Jinsha River valley from Qiaojia to Menggu has been repeatedly dammed by the landslide deposits since the mid-Pleistocene epoch. The valley evolution defers to the model of "cut-landslide-dammed-aggradation-cut". We calculated the incision rate based on the formation age and the height of the strath terraces near Hulukou, and found that the incision rate can be separated into two parts: before 0.82 Ma, the incision rate is 0.56 mm/a; from 0.82 Ma to now, it descended to 0.19 mm/a. We think this transition is induced by the frequent landslide events, which can bring a large amount of sediments to the river valley, and then impound a lake and accumulate sediments upstream, inhibiting the river incision. Synthesized studies of the fluvial terraces indicate that the formation of the modern valley of the Jinsha River may have begun in the late Early Pleistocene.

Key words: fluvial terrace, fluvial valley evolution, Jinsha River, Qiaojia-Menggu