Aeolian abrasion and modes of fine particle production from natural red dune sands: an experimental study
Aeolian abrasion and modes of fine particle production from natural red dune sands: an experimental study
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DOI：
10.1111/j.1365-3091.2004.00662.x
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发表时间：
2004-10-01
期刊：
影响因子：
3.5
通讯作者：
Pudmenzky, C
中科院分区：
文献类型：
--
作者：
Bullard, JE;McTainsh, GH;Pudmenzky, C
进行了一系列实验，以确定天然沙丘砂的风蚀产生细颗粒（< 125 μ m）的可能性：（1）释放残留的细粉;（2）颗粒的剥落、碎裂和破碎;（3）去除颗粒表面涂层。从四个活跃的大陆沙丘的表面获得母样，并使用玻璃“试管”室研磨长达120小时。在不同的时间间隔捕获由该研磨过程产生的细颗粒，并使用Coulter Multisizer进行详细的粒度分析。未处理的母体样品的磨损产生了两个主要尺寸类别之一的细颗粒，< 10 mum and >50 μ m，但是当母体样品被筛分以排除< 250 μ m的颗粒时，产生了相对更多的在10-50 μ m范围内的材料。对于未筛分的母体样品，与主导模式相关的尺寸范围根据磨损时间的长度而变化。粗粒模式（> 63妈妈）是占主导地位的第一个16小时的磨损，然后变得不那么重要，被认为是与居民细粉释放到悬浮液。最好的模式（< 10妈妈）是不存在或非常弱的磨损的前16小时，然后变得更加显着，在某些情况下，占主导地位的分布磨损继续。颗粒表面涂层的去除是< 10 μ m的细粒材料的主要来源，并且这可能是砂由次圆形和圆形颗粒主导的区域中细粒材料的重要来源。通过与以前的研究相比，风成颗粒磨损，这些天然沙丘砂产生的细料（重量）非常低的数量，但它们的空间范围使它们成为潜在的重要来源，在全球范围内的灰尘大小的颗粒。
A series of experiments was conducted to determine the potential for aeolian abrasion of natural dune sands to produce fine particles (< 125 mum) by (1) the release of resident fines; (2) spalling, chipping and breakage of particles; and (3) the removal of grain surface coatings. Parent samples were obtained from the surfaces of four active continental dunes and abraded using a glass 'test tube' chamber for up to 120 h. The fine particles produced by this abrasion process were trapped at varying time intervals and subject to detailed particle-size analyses using a Coulter Multisizer. The abrasion of untreated parent samples produced fine particles in one of two main size classes, < 10 mum and > 50 mum, but when the parent sample was sieved to exclude particles < 250 mum, relatively more material in the range 10-50 mum was produced. For unsieved parent samples, the size range associated with the dominant mode varied according to the length of the abrasion time. The coarsest mode (> 63 mum) was dominant during the first 16 h of abrasion, then became less significant and is thought to be associated with the release of resident fines into suspension. The finest mode (< 10 mum) was absent or very weak during the first 16 h of abrasion, then became more significant and, in some instances, dominated the distribution as abrasion continued. Removal of grain surface coatings is the main source of fine material < 10 mum, and this may be a significant source of fine material in areas where sands are dominated by subrounded and rounded particles. By comparison with previous studies of aeolian particle abrasion, these natural dune sands produced very low quantities of fine material (by weight), but their spatial extent makes them potentially a significant source of dust-sized particles at the global scale.