Bedrock structural control on catchment-scale connectivity and alluvial fan processes, High Atlas Mountains, Morocco
Bedrock structural control on catchment-scale connectivity and alluvial fan processes, High Atlas Mountains, Morocco
复制标题
摩洛哥高阿特拉斯山脉流域规模连通性和冲积扇过程的基岩结构控制
DOI：
10.1144/sp440.15
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
M. Stokes
中科院分区：
文献类型：
--
作者：
A. Mather;M. Stokes
岩性被认为是流域内部对邻近冲积扇流动过程的重要控制因素。然而，遗传构造构型（如基岩姿态）在集水区连通性和泥沙输运中的作用很少被考虑。我们从流域尺度连通性、沉积物转移和由此产生的冲积扇过程的角度，研究了摩洛哥高阿特拉斯地区dad<e:1>河谷的四个年轻（<100年）活跃支流接合冲积扇系统。这两个集水区在相同的岩性（灰岩和互层泥岩）上，但经历了不同的被动构造形态（倾斜层和构造增厚层）。风机系统对历史峰值流量（20-172 m3 s−1）的反应不同。含有构造增厚的石灰岩单元的集水区形成槽状峡谷，槽状峡谷作为沉积物转移的屏障，将集水区分隔开来，鼓励较低的沉积物在扇上流动。由于河道坡度陡峭，顺倾集水区促进了连通性和平移基岩滑坡的沉积物输送，鼓励了更多的沉积物流向水流。相比之下，走向导向流域的平移性滑坡通过压缩河谷宽度而破坏纵向连通性，而主要河道的坡度受到石灰岩层的姿态的抑制，从而鼓励局部回填。这减少了由此产生的水流的含沙量。
Abstract Lithology is acknowledged to be an important internal catchment control on flow processes to adjacent alluvial fans. However, the role of inherited structural configurations (e.g. bedrock attitude) in catchment connectivity and sediment transport is rarely considered. We examine four young (<100-year-old) active tributary junction alluvial fan systems from the Dadès Valley in the High Atlas of Morocco in terms of their catchment-scale connectivity, sediment transfer and resulting alluvial fan processes. The catchments occur on the same lithologies (limestones and interbedded mudstones), but experience different passive structural configurations (tilted and structurally thickened beds). The fan systems react differently to historical peak discharges (20–172 m3 s−1). Catchments containing tectonically thickened limestone units develop slot canyons, which compartmentalize the catchment by acting as barriers to sediment transfer, encouraging lower sediment to water flows on the fans. Syn-dip catchments boost connectivity and sediment delivery from translational bedrock landslides as a result of steep channel gradients, encouraging higher sediment to water flows. By contrast, translational landslides in strike-oriented drainages disrupt longitudinal connectivity by constricting the valley width, while the gradients of the main channels are supressed by the attitude of the limestone beds, encouraging localized backfilling. This diminishes the sediment to water content of the resulting flows.
影响因子：
3.9
作者：
François-Nicolas Krencker;S. Bodin;R. Hoffmann;G. Suan;E. Mattioli;L. Kabiri;K. Föllmi;A. Immenhauser-A.
通讯作者：
François-Nicolas Krencker;S. Bodin;R. Hoffmann;G. Suan;E. Mattioli;L. Kabiri;K. Föllmi;A. Immenhauser-A.