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    Testing the auto-abrasion hypothesis for dust production using diatomite dune sediments from the Bodélé Depression in Chad

    Bristow, Charlie S. and Moller, T.H. (2018) Testing the auto-abrasion hypothesis for dust production using diatomite dune sediments from the Bodélé Depression in Chad. Sedimentology 65 (4), pp. 1322-1330. ISSN 0037-0746.

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    Abstract

    This paper examines the role of quartz sand in the production of dust using mixtures of quartz sand from the Sahara and diatomite aggregates from the Bodélé Depression in Chad. An aeolian abrasion chamber is used to reproduce the physical processes of aeolian abrasion and test the hypothesis that the breakdown of saltating diatomite flakes as they collide in saltation, and with the surface, is the most prolific mechanism of dust production (auto-abrasion). This hypothesis is tested against the competing hypothesis that a hard, higher density quartz sand impactor is required to abrade fine-grained sediments to generate dust. The results show that dust can be produced by a mixture of saltating diatomite and quartz sand particles. However, quartz sand is not required for saltating aggregates to produce dust. Indeed these results, which used a mixture of very coarse-grained aggregate (1 to 2 mm diameter) with fine quartz sand, indicate that the addition of quartz sand can decrease dust production. For a very coarse aggregate (1 to 2 mm) a pure diatomite aggregate produced the most dust, although using a coarse-grained aggregate (0.5 to 1.0 mm) with a mixture of 20% quartz and 80% aggregate was found to produce the most dust overall. The results of this study confirm the auto-abrasion hypothesis for the breakdown of diatomite particles in the Bodélé Depression, which is the single biggest source of atmospheric mineral dust on Earth.

    Metadata

    Item Type: Article
    Additional Information: This is the peer reviewed version of the article, which has been published in final form at the link above. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
    Keyword(s) / Subject(s): Abrasion, aggregate, dust, Sahara, saltation, soil
    School: Birkbeck Schools and Departments > School of Science > Earth and Planetary Sciences
    Depositing User: Charles Bristow
    Date Deposited: 09 Oct 2017 13:39
    Last Modified: 30 Jul 2019 13:43
    URI: http://eprints.bbk.ac.uk/id/eprint/19972

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