COASTAL STRATIGRAPHIES AS INDICATORS OF ENVIRONMENTAL-CHANGES UPON EUROPEAN ATLANTIC COASTS IN THE LATE HOLOCENE

This paper is based upon work undertaken within contract EPOC-CT900001 5, in the Environment Programme (Third Framework), Commission of Europ ean Communities, Brussels. Late Holocene (post c.4000 BP) stratigraphi es from beach-barrier-lagoon environments are presented from five loca tions between northwest Spain (Galicia) and western Ireland. These mes o- to macrotidal coasts are conditioned by high energy waves and storm s. As such the coasts are sensitive potentially to the future impacts of rising sea-level and to climate-led controls on coastal behaviour. Consequently an objective of this study has been to establish the patt ern of physical environmental changes recorded here, as a basis for he lping assess the possible effects of future alterations in these coast al systems. The stratigraphies studied commonly show the occurrence of interleaved inorganic and organic sediments. The sedimentary sequence s together evidence the importance of sand movements, alternating irre gularly with periods of vegetation growth and relative environmental s tability. Mechanisms of onshore sediment transfer appear to be linked to aeolian action, possibly most associated with storms, and to barrie r over-washing. Repeated periods of sand movement are recorded particu larly in barrier environments from about the fifteenth century AD onwa rd. The nineteenth century to the present day also shows strong human influences upon coastal changes. Rates of relative sea-level rise on s ome coasts are placed at similar to 0.5-0.6mm yr(-1) post c.2000 BP. S tudies indicate that coastal barriers in Galicia appear to have been r elatively stable, or even to have prograded, during this period. In Br ittany and western Ireland similar systems record persistent retreat a nd barrier breakdown.