Várkonyi, Péter L. and Laity, Julie E. (2012) Formation of surface features on ventifacts: Modeling the role of sand grains rebounding within cavities. Geomorphology, 139 . pp. 220-229. ISSN 0169-555X http://resolver.caltech.edu/CaltechAUTHORS:20120402-110408419
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Surface textural features – pits, grooves, flutes, and scallops – of sand-blasted ventifacts have been attributed to various erosional mechanisms and to variations in material hardness. This study develops a numerical model of abrasion to examine feature formation by direct grain impacts. We demonstrate that abrasion by a continuous supply of impactors arriving from a single direction, each hitting the surface once, transforms existing cavities into transient features (similar to scallops, flutes, and pits), which shrink and eventually vanish. However, by incorporating additional impacts within the features from rebounding particles, persistent, continuously growing features emerge. We conclude that: (1) rebounding particles concentrate their effect within features, and therefore increase their size; (2) the development of features is sensitive to material type; and (3) the ultimate maximum feature scale is related to the size of the rock, and the size and velocity of impactors. Our model helps organize diverse ventifact field observations into an initial framework of pattern formation and confirms field and laboratory observations that the most common features are linear in wind-parallel directions.
|Additional Information:||© 2011 Elsevier B.V. Received 14 July 2010. Revised 17 October 2011. Accepted 17 October 2011. Available online 22 October 2011. PV would like to thank for the hospitality of the California Institute of Technology, and the financial support of a HAESF Senior Leaders and Scholars Fellowship as well as of OTKA Grant 72146. We would also like to thank the reviewers for their very helpful comments.|
|Subject Keywords:||Ventifacts; Abrasion Wind erosion; Geomorphological modeling; Numerical simulations|
|Official Citation:||Péter L. Várkonyi, Julie E. Laity, Formation of surface features on ventifacts: Modeling the role of sand grains rebounding within cavities, Geomorphology, Volumes 139–140, 15 February 2012, Pages 220-229, ISSN 0169-555X, 10.1016/j.geomorph.2011.10.021.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||11 Apr 2012 17:39|
|Last Modified:||11 Apr 2012 17:39|
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