HOLOCENE SEA-LEVEL VARIATIONS AND GEOMORPHOLOGICAL RESPONSE - AN EXAMPLE FROM NORTHERN BRITTANY (FRANCE)

In northern Brittany an important geomorphological response to Holocen e sea-level rise has been the development of coastal dunes with associ ated lagoons and marshes. At Anse du Verger, a marsh has formed behind a dune system which has been developing in situ for the last 4000 yea rs. The lithostratigraphy of the marsh comprises extensive peat format ion, with sands, silts and occasional sand lenses, the latter probably associated with storm surges. The sequence dates from 10,320+/-120 BP . After 3000 BP, flood episodes on the marsh are more common, while th e upper marsh deposits can be correlated with the recent period of dun e building. Prehistoric artifacts (remains of cooking implements) have been found on a cliff to the east of the marsh and are buried by wash over deposits, which indicates a sudden abandonment of a settlement po ssibly due to a storm surge soon after 2460+/-80 BP. Surge levels are proposed as a controlling factor on dune crest elevation. Copyright (C ) 1996 Elsevier Science Ltd