An optically stimulated luminescence dated Middle to Late Pleistocene fluvial sequence from the western Solent Basin, southern England

摘要

This paper presents numerical dating from a Middle to Late Pleistocene terrace deposit sequence in the Solent Basin, southern England. The sequence from the western part of the former Solent river system is one of the longest in Britain, with 18 mapped terrace aggradations. A set of 23 optically stimulated luminescence (OSL) dates aim to provide dated tie-points within the lower part of the sequence at five stratotype locations. These dates are replicated at single sites, providing age estimates for fewer members, but increasing the reliability for those members that have been dated. The results provide two reliably dated tie-points within the sequence and suggest that (i) the lowest six terrace aggradations all postdate ca. 275 kyr (MIS 8), (ii) terraces may have aggraded during cold phases within the penultimate interglacial (MIS 7) and (iii) the interglacial deposits at Stone Point whose age has previously been contested are likely to be of Ipswichian (last interglacial, MIS 5e) age. These findings are compared to previous age models in the western Solent basin, with which they agree in part. They may suggest that fluvial activity in the Solent was particularly dynamic during MIS 7.