Along‐Stream Variations in Valley Flank Erosion Rates Measured Using 10Be Concentrations in Colluvial Deposits From Canyons in the Atacama Desert
Along‐Stream Variations in Valley Flank Erosion Rates Measured Using 10Be Concentrations in Colluvial Deposits From Canyons in the Atacama Desert
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使用阿塔卡马沙漠峡谷崩积物中的 10Be 浓度测量谷侧侵蚀率的沿流变化
DOI：
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发表时间：
2021
影响因子：
5.2
通讯作者：
Sandrine Choy
中科院分区：
文献类型：
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作者：
V. Zavala;S. Carretier;V. Regard;S. Bonnet;R. Riquelme;Sandrine Choy
河谷的加宽和加深以不同的速度发生。这种共同进化在数千年来基本上没有记录。不确定的切割和加宽规律限制了模型再现侵蚀速率以及地质时间尺度上对构造和气候的响应的能力。我们研究了智利北方两个1 km深的峡谷，这两个峡谷的特征都是在一个主要的断裂带向上迁移后山谷变宽，但有一个历时性的切口开始。我们使用崩积沉积物中测量的10 Be浓度来量化沿着河谷侧翼的侵蚀速率E。我们观察到，E在结带中增加，具有明确的关系（R2 = 0.7）：E随谷床坡度准线性增加，随谷宽减小（指数为0.4）。我们的研究结果表明，E随时间的推移而减少，但山谷侧翼风化可能会维持一个显着的横向侵蚀率。我们的研究结果提供了数据测试侵蚀规律的山谷扩大。
The widening and deepening of river valleys occur at different rates. This co‐evolution is largely undocumented over thousands of years. Uncertainties on incision and widening laws limit the ability of models to reproduce erosion rates and responses to tectonics and climate over geologic timescales. We studied two 1 km‐deep canyons in northern Chile, both characterized by valley widening after the upward migration of a major knickzone but with a diachronous incision initiation. We use 10Be concentrations measured in colluvial deposits to quantify the erosion rates E of along‐stream valley flanks. We observe that E increases in the knickzone, with well‐defined relationships (R2 = 0.7): E increases quasilinearly with the valley‐bed slope and decreases with the valley width (exponent ∼‐0.4). Our results suggest that E decreases with time but that valley flank weathering may sustain a significant lateral erosion rate. Our results provide data for testing erosion laws governing valley widening.
影响因子：
18.3
作者：
Constantine, Jose Antonio;Dunne, Thomas;Lazarus, Eli D.
通讯作者：
Lazarus, Eli D.