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Lifespan of mountain ranges scaled by feedbacks between landsliding and erosion by rivers

机译:山脉的寿命取决于滑坡和河流侵蚀之间的反馈

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摘要

An important challenge in geomorphology is the reconciliation of the high fluvial incision rates observed in tectonically active mountain ranges with the long-term preservation of significant mountain-range relief in ancient, tectonically inactive orogenic belts. River bedrock erosion and sediment transport are widely recognized to be the principal controls on the lifespan of mountain ranges. But the factors controlling the rate of erosion and the reasons why they seem to vary significantly as a function of tectonic activity remain controversial. Here we use computational simulations to show that the key to understanding variations in the rate of erosion between tectonically active and inactive mountain ranges may relate to a bidirectional coupling between bedrock river incision and landslides. Whereas fluvial incision steepens surrounding hillslopes and increases landslide frequency9, landsliding affects fluvial erosion rates in two fundamentally distinct ways. On the one hand, large landslides overwhelm the river transport capacity and cause upstream build up of sediment that protects the river bed from further erosion. On the other hand, in delivering abrasive agents to the streams, landslides help accelerate fluvial erosion. Our models illustrate how this coupling has fundamentally different implications for rates of fluvial incision in active and inactive mountain ranges. The coupling therefore provides a plausible physical explanation for the preservation of significant mountain-range relief in old orogenic belts, up to several hundred million years after tectonic activity has effectively ceased.%山系在没有构造活动存在时预计会被侵蚀掉,但几个山系经过几亿年之后都保留了下来。一个新的模型研究表明,在构造上不活跃的山系寿命出乎意料地长可以通过一个反馈机制来解籽,该机制米自基岩河流下切作用与泥石流影响冲积侵蚀的各种不同方式之间的耦合。
机译:地貌学的一个重要挑战是,在长期处于构造活动的造山带中,长期保存在构造活跃的山脉中观察到的高河流切入率与长期保留的重要山脉之间的协调。河床基岩的侵蚀和泥沙输送被公认为是山脉寿命的主要控制手段。但是,控制侵蚀速率的因素以及它们似乎随着构造活动而显着变化的原因仍然存在争议。在这里,我们使用计算模拟来表明,了解构造活动山脉和非活动山脉之间侵蚀速率变化的关键可能与基岩河切口和滑坡之间的双向耦合有关。河流切口使周围的山坡变陡并增加了滑坡发生率9,而滑坡以两种根本不同的方式影响河流侵蚀速率。一方面,大的滑坡淹没了河流的运输能力,并导致上游沉积物堆积,从而保护了河床免受进一步的侵蚀。另一方面,在将磨蚀剂输送到河流中时,滑坡有助于加速河流侵蚀。我们的模型说明了这种耦合如何对活跃和不活跃山脉的河流切口速率产生根本不同的影响。因此,这种耦合为在构造活动有效停止长达数亿年之久的古老造山带中的重大山脉浮雕的保存提供了合理的物理解释。%山系在没有构造活动存在时预计会被侵蚀掉,但一个新的模型研究表明,在构造上不活跃的山系寿命出乎意料地长可以通过一个反馈机制来解籽,该机制米自基岩河流下切作用与泥石流影响冲积侵蚀的各种不同方式之间的补充。

著录项

  • 来源
    《Nature》 |2013年第7455期|475-478395|共5页
  • 作者单位

    Department of Geoscience, Aarhus University, Heegh-Guldbergs Gade 2,8000 Aarhus C, Denmark.;

    Department of Geoscience, Aarhus University, Heegh-Guldbergs Gade 2,8000 Aarhus C, Denmark.;

    School of Earth Sciences, University of Melbourne, Victoria 3010, Australia;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
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