Archaeology of the continental shelf: Marine resources, submerged landscapes and underwater archaeology
We provide a critical review of the evidence for the long-term use of marine resources and coastal environments in human evolution and later development. We emphasise the importance of the coastal archaeological record in understanding patterns of human settlement and dispersal and draw attention to the large potential biases introduced by the destructive or obscuring effects of Pleistocene sea-level change. We note that lowered sea levels have been the norm for most of the Pleistocene and that periods of high sea level have been too short-lived to provide other than a fragmentary coastal record and one that is beset with ambiguities and uncertainties. We examine the geological processes of coastal uplift and underwater preservation that may help to mitigate these biases. Coastlines elevated by isostatic and tectonic processes, or with very steep offshore drop-offs at plate boundaries, are important in providing a potential window into coastal landscapes and archaeology formed during periods of lowered sea level. However, we conclude that the opportunities afforded by these geological factors are too limited to obviate the need for underwater exploration. We review the evidence now available from submerged landscapes across the Africa-Eurasia interface from the Atlantic coastlines of Northwest Europe to the southern Red Sea. We show that geomorphological conditions for the preservation of archaeological and palaeoenvironmental data are commonly present, that much material has already been discovered, and that new techniques, technologies and projects are providing the momentum for a rapidly expanding field of investigation. The results do not simply add to what we already know from sites on land, but are likely to produce qualitatively different evidence for coastal adaptations and landscapes that have no analogue on present-day coastlines. We note the strong probability that many coastal landscapes exposed at lowered sea level provided relatively fertile and productive refugia for plants, land mammals and humans at a time when increased aridity would have reduced or deterred hinterland occupation. We conclude that underwater investigation is essential if hypotheses of early human adaptation and dispersal are to be fully tested.