Exceptional formation of present-day dunes in the Baie d' Audierne, southwestern Brittany, France
Guilcher, A.; Hallégouët, B.; Meur, C.; Talec, P.; Yoni, C. (1992). Exceptional formation of present-day dunes in the Baie d' Audierne, southwestern Brittany, France, in: Carter, R.W.G. et al. (Ed.) Coastal dunes: geomorphology, ecology and management for conservation: Proceedings of the 3rd European Dune Congress Galway, Ireland, 17-21 June 1992. pp. 15-23
In: Carter, R.W.G.; Curtis, T.G.F.; Sheehy-Skeffington, M.J. (Ed.) (1992). Coastal dunes: Geomorphology, ecology and management for conservation: Proceedings of the 3rd European Dune Congress Galway, Ireland, 17-21 June 1992. A.A. Balkema [etc.]: Rotterdam. ISBN 90-5410-058-3. 533 pp., more
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| Authors | | Top |
- Guilcher, A.
- Hallégouët, B.
- Meur, C.
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| Abstract |
Although dunes were still developing as late as the eighteenth century on the northwest coast of Brittany, perhaps as a result of a climatic change, today virtually no true dunes are forming. However, a quite exceptional case is the formation, since 1968, of a new dune belt in the south of the Baie d' Audierne, southwest Brittany, on a shore exposed to onshore winds and oceanic swells. These dunes have formed as a result of the destruction by man of a high gravel ridge, which controlled the recession of the coastline. During storms sand was available to be moved onto the backbarrier wetlands through wave-cut breaches in the remnants of the gravel ridge, to form deltas over a width of more than 200 m. The growth of these deltas allowed the building by onshore winds of low (up to 8.5 m) dunes, which were stabilized rapidly by vegetation (eg. Cakile maritima, Salsola kali, Ammophila arenaria). As a result the base level of the breaches rose and diverted the impounded freshwater to the north. During the 1989-1990 winter storms, large volumes of sand were moved through old and new breaches. During the following summer, dunes fed by this new supply of sand continued to expand and extend north-wards, to be colonized quickly by vegetation. This sequence of events is particularly interesting since it occurs in an area where new dune formation is unknown at the present time. |
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