Eel River margin source-to-sink sediment budgets: Revisited
Eel River margin source-to-sink sediment budgets: Revisited
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DOI：
10.1016/j.margeo.2014.03.008
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发表时间：
2014-05
期刊：
影响因子：
2.9
通讯作者：
J. Warrick
中科院分区：
文献类型：
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作者：
J. Warrick
鳗鱼河海岸边缘由于其陡峭、产沙量高和大陆架上沉积地层的形成而被用作代表性的源-汇沉积物扩散系统。以往研究的一个发现是，相邻大陆架仅保留了在单个洪水和20世纪的时间尺度上排放的鳗鱼河细粒沉积物（小于63 μm）的约25%，因此表明鳗鱼架捕获效率低于其他类似系统。在这里，我提供的数据和分析表明，在鳗鱼河的泥沙排放关系随时间变化很大，包括悬浮泥沙浓度在世纪后期大幅下降。包括这些趋势在边缘范围内的泥沙预算，我表明，以前的鳗鱼河泥沙排放率被高估了两个因素。因此，修订后的沉积物预算显示，鳗鱼架保留了约50%的排放河流细颗粒悬浮泥沙在1995-97年和20世纪世纪的密集采样事件。有鉴于此，应重新评估关于沉积物从主要陆架沉积中心大量输出的假设。
The Eel River coastal margin has been used as a representative source-to-sink sediment dispersal system owing to its steep, high-sediment yield river and the formation of sedimentary strata on its continental shelf. One finding of previous studies is that the adjacent continental shelf retains only ~ 25% of the Eel River fine-grained sediment (less than 63 μm) discharged over time scales of both individual floods and the 20th century, thus suggesting that the Eel shelf trapping-efficiency is uniquely lower than other similar systems. Here I provide data and analyses showing that sediment discharge relationships in the Eel River have varied strongly with time and include substantial decreases in suspended-sediment concentrations during the latter 20th century. Including these trends in margin-wide sediment budgets, I show that previous Eel River sediment discharge rates were overestimated by a factor of two. Thus, revised sediment budgets shown here reveal that the Eel shelf retained ~ 50% of the discharged river fine-grained suspended sediment during intensively sampled events of 1995–97 and over the 20th century. In light of this, hypotheses about high rates of sediment export away from the primary shelf depocenter should be reevaluated.