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Morphometric analysis of slipface processes of an aeolian dune: Implications for grain-flowdynamics

Cornwall, Carin, Jackson, Derek W. T., Bourke, Mary and Cooper, JAG (2018) Morphometric analysis of slipface processes of an aeolian dune: Implications for grain-flowdynamics. Sedimentology, x (x). x-x. [Journal article]

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DOI: 10.1111/sed.12456

Abstract

Grain flows are an integral part of sand dune migration; they are a direct response to the local windregime and reflect complex interactions between localized over-steepening of a dune slipface andcomplex turbulent airflow on the lee slope. Grain flows are primarily responsible for delivering sediment to the base of a dune, thus driving slipface advancement; yet, there are few constraints on their morphological and spatial characteristics or the amount of sediment that is redistributed bythese flows. Using a combination of high-resolution terrestrial laser scanning and video recordings,four distinct grain-flow types are identified based on morphology and area on a dune slipface. Grainflow morphologies range from small, superficial flows to larger flows that affect greater portions of the slipface, moving significant amounts of sediment. Detailed field observations are presented of the dynamics of lee slopes, including measurements of the initiation location, thickness, magnitude and frequency statistics of grain flows, as well as volume estimates of redistributed sediment for each grain flow observed. High-resolution laser scans enable accurate quantification of bulk sediment transfer from individual grain flows and can be used to study grain flows in a variety of environments. A categorization of grain-flow morphologies is presented that links styles of flows with wind strength and direction, turbulent airflow, sediment deposition and environment.

Item Type:Journal article
Keywords:aeolian slipface dunes grainflow grainfall
Faculties and Schools:Faculty of Life and Health Sciences > School of Geography and Environmental Sciences
Faculty of Life and Health Sciences
Research Institutes and Groups:Environmental Sciences Research Institute > Coastal Systems
Environmental Sciences Research Institute
ID Code:39554
Deposited By: Professor Derek Jackson
Deposited On:16 Feb 2018 15:26
Last Modified:16 Feb 2018 15:26

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