EGU24-5314, updated on 08 Mar 2024
https://doi.org/10.5194/egusphere-egu24-5314
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Increasing fluvial incision rate in the southern Jinshan Gorge from tributary terraces and river network analysis

Yuezhi Zhong1, Vincenzo Picotti1, Jianguo Xiong2, Sean Willett1, Christoph Schmidt3, and Georgina King3
Yuezhi Zhong et al.
  • 1Department of Earth Sciences, ETH Zurich, Sonneggstrasse 5, 8092 Zurich, Switzerland
  • 2State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China
  • 3Institute of Earth Surface Dynamics, University of Lausanne, Bâtiment Géopolis 5875, 1015 Lausanne, Switzerland

Base level fall on a tributary is genetically related to its trunk channel incision, and analysis of tributaries thus provides information of the trunk channel evolution history. In the middle Yellow River, for example, several integration processes were proposed and should be consistent with river terrace data from the trunk channel. We investigate the rates and spatiotemporal variations of incision along the Jinshan Gorge in the middle Yellow River with dated strath terraces from its tributaries. The incision rate for six tributaries along the Jinshan Gorge is constrained using mapped and dated terraces. By comparing terraces of similar age, we find generally decreasing incision rates from the confluence with the trunk river to upstream within a tributary in the southern Jinshan Gorge. Decreasing incision rates are also observed among tributaries from south to north along the gorge. The results independently confirm the spatial pattern from “pseudo-terraces” derived from channel profile modeling. This interpretation reinforces the previous proposal that paleo-lake regressions in the Weihe Graben or integration with the Hetao Graben are unlikely to have been responsible for recent incision. An estimation method with terrace data within a tributary of erodibility coefficient, K, a crucial parameter for river profile inversion analysis, is also provided. K is recalibrated to be 1.03 10-5 m0.3/a with all terrace data. With an assemblage of published terrace data along the Jinshan Gorge, we suggest a re-examination of published terrace ages, which may help unravel the mysterious evolution history of the middle Yellow River.

How to cite: Zhong, Y., Picotti, V., Xiong, J., Willett, S., Schmidt, C., and King, G.: Increasing fluvial incision rate in the southern Jinshan Gorge from tributary terraces and river network analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5314, https://doi.org/10.5194/egusphere-egu24-5314, 2024.