Morphodynamics of submarine channel inception revealed by new experimental approach.
Morphodynamics of submarine channel inception revealed by new experimental approach.
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DOI：
10.1038/ncomms10886
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发表时间：
2016-03-21
影响因子：
16.6
通讯作者：
Cartigny MJ
中科院分区：
文献类型：
--
作者：
de Leeuw J;Eggenhuisen JT;Cartigny MJ
海底河道无处不在，它们的形成和演化是浑浊流与海底演化的动力相互作用的结果。然而，航道起始和水流动力学之间的地貌动力学联系还没有在实验中监测到，而且只在现代海底上有一次监测。以前的实验水流没有显示出航道起始，因为水流条件没有适当的比例来维持悬浮泥沙的输送。在这里，我们引入并应用了新的标度约束，以求自然浑浊流和实验浑浊流之间的相似性。定标的电流从最初没有特征的斜率启动了一条堤坝通道。沟道化始于某些坡段的堤防淤积和其他路段的管道侵蚀。在随后的水流中，河道泄压和水流限制逐渐增加。这种地貌动力学演化决定了海底河道沉积在地层记录中的结构和沉积物绕行到盆地底部的效率。悬浮泥沙流穿过海底的水道，将大量沉积物输送到深海。在这里，作者用一种新的方法进行了大规模的实验室实验，展示了这些洋流和它们的沉积物之间的反馈如何驱动这些海底水道的形成。
Submarine channels are ubiquitous on the seafloor and their inception and evolution is a result of dynamic interaction between turbidity currents and the evolving seafloor. However, the morphodynamic links between channel inception and flow dynamics have not yet been monitored in experiments and only in one instance on the modern seafloor. Previous experimental flows did not show channel inception, because flow conditions were not appropriately scaled to sustain suspended sediment transport. Here we introduce and apply new scaling constraints for similarity between natural and experimental turbidity currents. The scaled currents initiate a leveed channel from an initially featureless slope. Channelization commences with deposition of levees in some slope segments and erosion of a conduit in other segments. Channel relief and flow confinement increase progressively during subsequent flows. This morphodynamic evolution determines the architecture of submarine channel deposits in the stratigraphic record and efficiency of sediment bypass to the basin floor. Suspended sediment currents travel through channels on the ocean floor to deliver enormous volumes of sediment to the deep ocean. Here, using a new approach for scaled laboratory experiments, the authors show how feedback between these currents and their deposits drive the formation of these submarine channels.