Holocene formation and evolution of coastal dunes ridges, Brittany (France) - 24/09/16
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Abstract |
Holocene coastal dune formation under a continuously rising sea level (SL) is an abnormal response to increasing storm frequency. The aim of this work is to understand the coastal sedimentary budget and the present-day sand starvation, controlled by climate and man. Dating in Brittany shows that Aeolian deposition initiated from ca. 4000cal BP, with the slowing down of the SL rise. Pre-historical dunes appeared here from ca. 3000cal BP, without SL regression. After, further building phases recycled the same stock of sands. Historical dunes I developed from ca. 350 AD. Major storms between 900 and 1200 AD resulted in the construction of washover coastal ridges, the Historical dunes II. A part of the sand was evacuated offshore. From ca. 1350 AD, the pre-existing ridges are reworked forming the Historical dunes III, leading to rapid coastal erosion and inland drift. Holocene dunes with a rising SL constitute a temporary anomaly, mostly forced by man, soon erased by storms in Brittany.
Le texte complet de cet article est disponible en PDF.Keywords : Dunes, Holocene, Climate, Sand starvation, Anthropic perturbation
Plan
Vol 348 - N° 6
P. 462-470 - juillet 2016 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.