Lyell Collection
Geological Society, London, Special Publications
Lyell Centre  |   Lyell Collection  |   Subscriptions   |   Geological Society  |   Email alerts  |   Online bookshop  |   Help

Keywords:
Author:
Advanced search>>
This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Schmitt, T.
Right arrow Articles by Ramsay, T. S.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation
Geological Society, London, Special Publications; 2007; v. 274; p. 53-64;
DOI: 10.1144/GSL.SP.2007.274.01.07
© 2007 Geological Society of London

Use of swath bathymetry in the investigation of sand dune geometry and migration around a near shore ‘banner’ tidal sandbank

Thierry Schmitt*, Neil C. Mitchell & Tony S. Ramsay

School of Earth, Ocean and Planetary Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3YE, UK

Banner tidal sandbanks in the Bristol Channel have been repeatedly surveyed with a multibeam sonar to study the geometry and migration patterns of superimposed dunes. The data presented in this paper constitute one of the first studies concerned with sediment transport around a banner sandbank (Helwick Sands in the Bristol Channel) using repeated swath- bathymetry. The data reveal that the dunes maintain their shapes over a period of 11 months, and that they migrate in opposite directions on the alternate sides of the bank. Curiously, dunes connect over the crest of the bank despite opposing sediment transport directions on the flanks. Dune height increases with water depth as found in similar environments. We suggest how the morphology of the dunes results from the complex interaction between surface waves and tidal currents that occurs within the proximity of the headland.