L'élévation et les variations du niveau marin à l'Holocène terminal dans l'Ouest français : une approche par les dépôts de tempêtes Sea-level elevation and variation during late holocene in western France ; storm surge relicts as indicators

摘要

During late Holocene sea-level in Britain (Western France) has been rising slowly. Though, some rapid rise and fall events have been documented, together with extreme storms surges. In order to understand better this chronology field work has been undertaken in specific places, where extreme events are easy to distinguish from long term trends. The first results of this european contract (ENV4 CT 97 0488, University of Coventry) are presented. Some new information about oscillations of sea-level is develloped. Storm surge deposits are more frequently found in the 2600-2300 period. This may be explained by a climatic shift occuring at that time, but also because of better local conditions for deposit preservation. Morphological effects of the S.L.R. are discussed : rapid events, such as storms do not appear to modify significantly the meso-scale rythm of barrier evolution. These results are close to those predicted by models. At micro-scale level, evolution is not responding to model and rapid events seem to have quite an important role.