THE USE OF HISTORIC URBAN WATERFRONT SEQUENCES IN NORTH-WEST EUROPE AS HIGH RESOLUTION PALAEOENVIRONMENTAL PROXIES

Towns in North-west Europe began to develop from the 1st century AD onwards. After going into decline in the immediate aftermath of Roman withdrawal from the fourth century AD, towns blossomed once more from the 8th century AD onwards. Many towns founded during the Roman and early Medieval period were sited next to either rivers or estuaries for reasons of trade and transport, as well as access to a water supply. Therefore in order to protect the towns from flooding, while also providing platforms for quays and other harbour installations, wooden revetments were built. These frequently survive in the archaeological record, preserving in their lea thick stratigraphic sequences. The sediments that comprise these are of a variety of facies indicating changing river/estuary environments, but include laminated deposits reflecting rhythmic sedimentation at a sub-annual scale. As the revetment structures are often of oak they can be precisely dated using dendrochronology. This has enabled precise chronologies to be determined for the trapped laminated sediments. Stratigraphic and laboratory analytical study of such laminated sequences in London (England) and Utrecht (Netherlands) has demonstrated that human impact caused by the urban communities was significant during the later Roman period and again in the later Middle Ages. This impact manifested itself in the release of metal and organic pollutants into adjacent rivers, as well as the input of microartefacts into the alluvial and intertidal sediments.