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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >Fluvial incision and coarse gravel redistribution across the modern Dead Sea shelf as a result of base-level fall
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Fluvial incision and coarse gravel redistribution across the modern Dead Sea shelf as a result of base-level fall

机译：由于基础落下，河流切口和粗砾石再分配地面的现代死海架子

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Global eustatic lowstands can expose vast areas of continental shelves, and occasionally the shelf edge and the continental slope. The degree of fluvial connectivity to receding shores influences the redistribution of sediments across these emerging landscapes. Shelf and slope emergence in the Dead Sea since the middle of the 20th century, offers a rare opportunity to examine evolution of stream connectivity in response to continuous base-level decline. We characterize the connectivity evolution of two streams, using high-resolution time series of aerial imagery and elevation models, field mapping, and grain-size analyses. Our rich spatiotemporal dataset of evolving channel geomorphology, sediment transport conditions, and sediment redistribution, allows calculating potential coarse sediment mobility in response to base level decline. Following shelf emergence, alluvial fans first prograded onto the low-gradient shelf under unfavourable conditions for transporting coarse sediment to the regressing shoreline. Then, with shelf and slope emergence, the two adjacent streams evolved differently. The smaller, more arid watershed still maintains its highstand delta progradation on the shelf and is practically disconnected from the receding lake. The larger catchment, heading in wetter environments and having a narrower shelf, has incised the shelf and renewed and gradually intensified the sediment transport from the highstand to the lowstand delta. Sediment mobilization to lowstand shorelines is controlled by the evolution of the channel profile and by the average speed of gravel transport (10s-100s m yr(-1)). These findings from the Dead Sea are relevant to fluvial processes operating on continental shelves during glacial maxima. Streams would have commonly stored high proportions of their coarse sediment on the continental shelves rather than efficiently connecting with the lowstand level. Additionally, differences in sediment routing patterns should exist among nearby s
机译：全球欧姆图削减可能会暴露大陆架的大面积，偶尔是搁板边缘和欧陆坡。对后退海岸的河流连接程度影响了这些新兴景观的沉积物的重新分配。自20世纪中叶自20世纪中叶以来死海的货架和坡地出现，难以追求持续基础级别的流动连接的演变。我们使用高分辨率时间序列的空中图像和高程模型，现场映射和晶粒尺寸分析来表征两条流的连通性演化。我们丰富的时空数据集演化的通道地貌，沉积物运输条件和沉积物再分配，允许计算潜在的粗泥落流动，以响应基础水平下降。在架子出现之后，在不利的条件下，冲积风扇首先将低梯度架子置于低梯度架上，以将粗沉积物运输到回归海岸线。然后，用架子和斜率出现，两个相邻的流变化不同。较小的，更干旱的流域仍然保持其在架子上的高度倾角促进，并且实际上与后德湖断开连接。较大的集水区，在潮湿的环境中，具有较窄的货架，具有较窄的架子并更新并逐渐将沉积物运输从高层延伸到低位Δ。通过沟道型材的演变和砾石传输的平均速度（10s-100s m Yr（-1））的平均速度控制沉积物。死海的这些发现与在冰川最大值期间在陆地架上运行的河流过程。溪流将在大陆架上常用的粗沉积物的高比例，而不是有效地与划分水平有效地连接。此外，附近的沉积路由模式的差异应该存在

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