Pleistocene marine and periglacial deposits of the English Channel

The Pleistocene marine and associated periglacial deposits of the coasts of southern England from Cornwall to Sussex, the British Channel Islands, and northern France from Brittany and Normandy to the Pas de Calais are described. The deposition of almost all marine deposits is ascribed to temperate conditions, although large igneous erratic boulders may have been emplaced by shore-ice rafting at the end or beginning of cold stages. The balance of the evidence from a variety of dating methods including U-series dating, amino-acid geochronology and biostratigraphy of associated terrestrial formations indicates that deposits of the last three pre-Holocene temperate marine oxygen isotope stages (stages 9, 7 and substage 5e) can readily be identified along much of both coastlines of the Channel. Deposits attributable to stages 11 and 13 are uncommon and best seen in the staircase of marine terraces backing the Hampshire-Sussex coastal plain and perhaps in western Brittany and the Boulonnais. The height above modern sea-level of the marine deposits is thought to be the result of slow uplift of the coastal zone caused by the isostatic response to sediment unloading during accelerated phases of erosion in cold stages, although deep-seated tectonics also may have been partly responsible for uplift. However, the height above modern sea-level of a deposit alone is riot on its own an indicator of age. Periglacial head deposits are mainly exposed along the coasts, with the sections showing frost shattered debris moved downslope by cryoreptation (frost-creep). The age of these deposits is uncertain, although they appear to be principally of marine oxygen isotope stages 4 and 2 in age. Some remnants of marine oxygen isotope stage 6 or 8 head deposits are present both in England and northern France. in a few places with good dating control, head deposits dating to the marine oxygen isotope stage 12 can be recognised. The age of the head deposits in most sections is based on their stratigraphical relationship with loess, palaeosols and on the dating of the underlying raised beaches. Copyright (C) 2003 John Wiley Sons, Ltd.