Channel mobility drives a diverse stratigraphic architecture in the dryland Mojave River (California, USA),Earth Surface Processes and Landforms

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Channel mobility drives a diverse stratigraphic architecture in the dryland Mojave River (California, USA)
Earth Surface Processes and Landforms ( IF 2.8 ) Pub Date : 2020-03-04 , DOI: 10.1002/esp.4841
Alessandro Ielpi ₁ , Mathieu G.A. Lapôtre ₂ , Alvise Finotello _{3,

4} , Massimiliano Ghinassi ₃ , Andrea D'Alpaos ₃

Affiliation

The links between flood frequency and rates of channel migration are poorly defined in the ephemeral rivers typical of arid regions. Exploring these links in desert fluvial landscapes would augment our understanding of watershed biogeochemistry and river morphogenesis on early Earth (i.e. prior to the greening of landmasses). Accordingly, we analyse the Mojave River (California), one of the largest watercourses in the Great Basin of the western United States. We integrate discharge records with channel‐migration rates derived from dynamic time‐warping analysis and chronologically calibrated subsidence rates, thereby constraining the river's formative conditions. Our results reveal a slight downstream decrease in bankfull discharge on the Mojave River, rather than the downstream increase typically exhibited by perennial streams. Yet, the number of days per year during which the channel experiences bankfull or higher stages is roughly maintained along the river's length. Analysis of historical peak flood records suggests that the incidence of channel‐formative events responds to modulation in watershed runoff due to the precipitation in the river's headwaters over decades to centuries. Our integrated analysis finally suggests that, while maintaining hydraulic geometries that are fully comparable with many other rivers worldwide, ephemeral desert rivers akin to the Mojave are capable of generating a surprisingly wide range of depositional geometries in the stratigraphic record. © 2020 John Wiley & Sons, Ltd.

中文翻译：

通道流动性在干旱的莫哈韦河（美国加利福尼亚）上驱动着多样化的地层结构

在干旱地区典型的短暂河流中，洪水频率与河道迁移速率之间的联系定义不清。探索沙漠河流景观中的这些联系将增进我们对地球早期（即，在大陆土地绿化之前）流域生物地球化学和河流形态发生的理解。因此，我们分析了莫哈韦河（加利福尼亚州），这是美国西部大盆地中最大的河道之一。我们将流量记录与从动态时间扭曲分析得出的河道迁移率和按时间顺序校准的沉降率相结合，从而限制了河流的形成条件。我们的结果表明，莫哈韦河上的河岸流量在下游略有下降，而不是常年河流通常表现出的下游增加。然而，沿河的长度大致保持了河道每年经历满水或更高水位的天数。对历史洪峰记录的分析表明，河道上游事件的发生与流域径流的调节有关，这归因于数十年来至数百年间河源头的降水。我们的综合分析最终表明，在保持与世界上许多其他河流完全可比的水力几何形状的同时，类似于莫哈韦沙漠的短暂沙漠河流能够在地层记录中产生出乎意料的广泛沉积几何形状。分级为4 +©2020 John Wiley＆Sons，Ltd. 对历史峰值洪水记录的分析表明，河道上游事件的发生与流域径流的调节有关，这归因于数十年来至数百年间河源头的降水。我们的综合分析最终表明，在保持与世界上许多其他河流完全可比的水力几何形状的同时，类似于莫哈韦沙漠的短暂沙漠河流能够在地层记录中产生出乎意料的广泛沉积几何形状。分级为4 +©2020 John Wiley＆Sons，Ltd. 对历史洪峰记录的分析表明，河道上游事件的发生与流域径流的调节有关，这归因于数十年来至数百年间河源头的降水。我们的综合分析最终表明，在保持与世界上许多其他河流完全可比的水力几何形状的同时，类似于莫哈韦沙漠的短暂沙漠河流能够在地层记录中产生出乎意料的广泛沉积几何形状。分级为4 +©2020 John Wiley＆Sons，Ltd. 在保持与世界上许多其他河流完全可比的水力几何形状的同时，类似于莫哈韦沙漠的短暂沙漠河流能够在地层记录中产生出乎意料的广泛沉积几何形状。分级为4 +©2020 John Wiley＆Sons，Ltd. 在保持与世界上许多其他河流完全可比的水力几何形状的同时，类似于莫哈韦沙漠的短暂沙漠河流能够在地层记录中产生出乎意料的广泛沉积几何形状。分级为4 +©2020 John Wiley＆Sons，Ltd.

更新日期：2020-03-04

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