The role of lateral erosion in the evolution of nondendritic drainage networks to dendricity and the persistence of dynamic networks
The role of lateral erosion in the evolution of nondendritic drainage networks to dendricity and the persistence of dynamic networks
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DOI：
10.1073/pnas.2015770118
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发表时间：
2021-04-20
影响因子：
11.1
通讯作者：
Parker, Gary
中科院分区：
文献类型：
--
作者：
Kwang, Jeffrey S.;Langston, Abigail L.;Parker, Gary
树枝状，即，树状的河流网络是地球景观中无处不在的特征;然而，河流网络如何以及为什么组织成这种形式还不完全清楚。分支模式被认为是最佳状态。因此，我们应该期待河流演化模型将（次优的）纯非树枝状网络彻底重组为（更优的）树枝状网络。到目前为止，目前的物理基础上的流域演变模型是无法实现这一结果，没有大量的外源强迫。在这里，我们提出了一个模型，确实完成了大规模的排水重组。在我们的模型中的关键特征是盆地范围内的基岩通道的横向切口。添加此子模型允许河道横向迁移，从而生成河流捕获事件和排水迁移。在模型中，决定排水网络重组的速率和频率的一个重要因素是两个参数的比率，横向和垂直岩石可蚀性常数。此外，我们的模型是独一无二的，因为它的模拟接近动态稳态。在动态稳定状态下，排水网络持续重组，而不是接近一个稳定的配置。我们的模型结果表明，横向基岩切割过程可以驱动主要的排水重组，并解释地球上的景观明显的长期瞬态。
Dendritic, i.e., tree-like, river networks are ubiquitous features on Earth's landscapes; however, how and why river networks organize themselves into this form are incompletely understood. A branching pattern has been argued to be an optimal state. Therefore, we should expect models of river evolution to drastically reorganize (suboptimal) purely nondendritic networks into (more optimal) dendritic networks. To date, current physically based models of river basin evolution are incapable of achieving this result without substantial allogenic forcing. Here, we present a model that does indeed accomplish massive drainage reorganization. The key feature in our model is basin-wide lateral incision of bedrock channels. The addition of this submodel allows for channels to laterally migrate, which generates river capture events and drainage migration. An important factor in the model that dictates the rate and frequency of drainage network reorganization is the ratio of two parameters, the lateral and vertical rock erodibility constants. In addition, our model is unique from others because its simulations approach a dynamic steady state. At a dynamic steady state, drainage networks persistently reorganize instead of approaching a stable configuration. Our model results suggest that lateral bedrock incision processes can drive major drainage reorganization and explain apparent long-lived transience in landscapes on Earth.