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中国科学院大学学报 ›› 2024, Vol. 41 ›› Issue (2): 212-221.DOI: 10.7523/j.ucas.2022.056

• 地质与地球科学 • 上一篇    下一篇

构造活动与地表作用耦合下的河流演化过程及动力学机制——以青海湖和倒淌河为例

苗宇1, 张怀1,2, 石耀霖1   

  1. 1 中国科学院大学地球与行星科学学院 中国科学院计算地球动力学重点实验室, 北京 100049;
    2 南方海洋科学与工程广东省实验室(珠海), 广东 珠海 519080
  • 收稿日期:2022-01-10 修回日期:2022-06-06 发布日期:2022-06-29
  • 通讯作者: 张怀,E-mail:hzhang@ucas.ac.cn
  • 基金资助:
    国家杰出青年科学基金(41725017)和国家重点研发计划项目(2020YFA0713400)资助

Dynamic mechanism and river evolution under coupling effects of surficial and tectonic processes: a case study of Qinghai Lake and Daotang River

MIAO Yu1, ZHANG Huai1,2, SHI Yaolin1   

  1. 1. CAS Key Laboratory of Computational Geodynamics, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
    2. Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519080, Guangdong, China
  • Received:2022-01-10 Revised:2022-06-06 Published:2022-06-29

摘要: 新生代以来,青海湖在河流侵蚀与构造活动耦合下由外流湖泊转化为内流湖泊,但其动力学成因一直悬而未决。倒淌河作为青海湖由外流转换为内流的关键通道,其动力学演化历史记录着这一重要的构造与地貌转变地质事件。基于最新开发的地貌演化有限体积法数值计算程序,模拟山脉隆升与河流下切共同作用下的河流倒淌形成与演化过程,定量分析隆升速率和河流下切系数对不同的流域演化模式的影响,探讨倒淌河演化的动力学机制,为认识倒淌河流域形成过程与青海湖形成成因提供支撑。结果表明,倒淌河流域的水系重组和倒淌河流向的转变主要受到由日月山断层活化引起的山脉快速隆升与河流下切影响;日月山隆升速率是影响倒淌河流域能否发生水系重组的控制因素;当河流被隆升的山脉阻挡而倒淌时,河流下切系数是控制流域重组速率的因素。

关键词: 青海湖, 倒淌河, 山脉隆升速率, 河流下切系数, 数值模拟

Abstract: Since the late Cenozoic, the geodynamic mechanism of the transformation of Qinghai Lake from the external lake to the endorheic lake is still an open problem. The Daotang River is an important channel for transforming from external-flow to the endorheic-flow type of Qinghai Lake. Its evolution records the prominent landform transition event. Based on the newly developed numerical calculation program for geomorphic evolution with finite volume method, in this work, we conduct a series of the landscape evolution models of the Daotang River under the combined influence of mountain uplift and river downcutting, and have a quantitative analysis of the effects of uplift rate and river undercutting coefficient on river backflow patterns. We attempt to explore the mechanism of landform transition events that could provide evidence for the formation process of Daotang River basin and the origin of Qinghai Lake. Our modeling results indicate that the reorganization of the river system and backward flow of the river is jointly controlled by the rapid mountain uplift from the Riyue Mountain active fault and the river undercutting coefficient. The mountain uplift rate is the controlling factor that affects the reorganization of the river system in the Daotang River basin. When rising mountains block the river, the river incision coefficient is the factor that controls the rate of reorganization that occurs in the basin. The result recognizes they have enlightening significance for further understanding the dynamic mechanism of river evolution under the regional tectonic deformation and the coupled surface processes.

Key words: Qinghai Lake, Daotang River, mountain uplift rate, river undercutting coefficient, numerical modeling

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