Palaeoenvironmental Reconstruction from Sediments at West Quay Road, Southampton

Abstract This detailed study of a 13m deep borehole from West Quay Road, Southampton documents estuary evolution over the Holocene in a locality which has received little attention in the literature. The work was undertaken by the Museum of London Archaeology Service Geoarchaeology department. The sediment sequence along with evidence from pollen, plant macrofossils, diatoms, ostracods, snails and radiocarbon dating shows the gradual drowning of the valley from the Lateglacial to the historic period. The evidence shows shifts in floral and faunal communities as coastal and estuarine habitats encroach inland with sea-level rise. Thick fen carr peat developed from the early Mesolithic over river terrace gravels and freshwater channels, while Boreal forest thrived in the surroundings. As tidal environments became more influential, a mosaic of reed beds and salt marsh pools developed by the late Mesolithic. A period of estuary contraction is indicated by the growth of freshwater sedge fen around the early to mid Neolithic, followed by clear marine transgression and persistence of estuarine mudflat environments into the historic period. The work supports the three phase model of Holocene estuary development of Long et al. (2000) which concluded that regional processes control estuary evolution. Although small-scale, this project contributes to the wider palaeogeographic and palaeoenvironmental picture within the Solent, and initiatives such as this form the backdrop for archaeological studies in the region. The length of the sedimentary archive and the amount of information gained show the value of geoarchaeological boreholes undertaken as part of developer-funded projects.