Making loess-sized quartz silt: data from laboratory simulations and implications for sediment transport pathways and the formation of 'desert' loess deposits associated with the Sahara
Making loess-sized quartz silt: data from laboratory simulations and implications for sediment transport pathways and the formation of 'desert' loess deposits associated with the Sahara
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DOI：
10.1016/s1040-6182(00)00085-9
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发表时间：
2001-02
影响因子：
2.2
通讯作者：
J. Wright
中科院分区：
文献类型：
--
作者：
J. Wright
从一系列的实验室模拟设计调查石英粉砂生成的一些地貌机制的结果进行了审查。然后，这些研究结果被用来讨论潜在的沉积物途径参与形成的“沙漠”黄土沉积物和路径，提出了一个建议的事件序列参与形成的黄土沉积物与撒哈拉沙漠。结果表明，河流和风成系统可以非常有效地产生石英粉砂。有人建议，在炎热的沙漠环境中的河流系统可能发挥核心作用的生产和分布的黄土质粉砂。首先，高能量，但周期性的河流制度与干旱和半干旱环境可能是负责相当数量的颗粒粉碎。第二，这些系统的间歇性将有助于保持地貌活跃的表面，淤泥大小的材料可以很容易地放气。除了河流破碎作用外，一系列风化机制和风成磨蚀作用也可能是“沙漠”黄土中粉砂产生的原因。因此，泥沙来源和机制的泥沙生成可能是更多样化的“沙漠”黄土比那些与冰川黄土。
Results from a series of laboratory simulations designed to investigate quartz silt generation by a number of geomorphic mechanisms are reviewed. These findings are then used to discuss potential sediment pathways involved in the formation of ‘desert’ loess deposits and a pathway is presented to show a proposed sequence of events involved in the formation of the loess deposits associated with the Sahara. The results indicate that both fluvial and aeolian systems can be very effective at producing quartz silt. It is suggested that fluvial systems within hot desert environments may play a central role in both the production and distribution of loessic silt. First, the highly energetic but periodic fluvial regimes associated with arid and semi-arid environments may be responsible for considerable quantities of particle comminution. Second, the intermittent nature of these systems will help maintain geomorphologically active surfaces from which silt-sized material can be easily deflated. As well as fluvial comminution, a range of weathering mechanisms and aeolian abrasion may also be responsible for the generation of silts in ‘desert’ loess. Consequently, silt sources and mechanisms of silt generation are likely to be much more diverse for ‘desert’ loess than those associated with glacial loess.