River terrace systems in north-west Europe: an archive of environmental change, uplift and early human occupation

Staircases of large-scale aggradational river terraces are a notable feature of many valleys in the temperate lattitudes, particularly in areas beyond the reach of the erosive activities of Pleistocene ice sheets. It is now recognized that the cyclic fluctuations of climate during the Quaternary have driven the generation of terraces, through the direct and indirect influence of both temperature and precipitation on fluviatile activity. Where fossiliferous deposits are preserved within terrace sequences it is often possible to date these and to correlate them with the oceanic record; thus providing an important framework for the evidence of environmental change on land. Middle and Late Pleistocene terraces in different areas can commonly be seen to have formed in synchrony with glacial-interglacial cycles or with longer-periodicity megacycles. Climatic forcing alone is insufficient to cause terraces to form, however; uplift is also necessary, so that terrace sequences can provide a useful record of crustal movement. In northwest Europe, where some of the best known studies of river terrace sequences have been carried out, the fluviatile deposits are also an important repository for Palaeolithic artefacts, from which a record of early human occupation can be reconstructed. (C) 2000 Elsevier Science Ltd. All rights reserved.