Re-excavating Europe’s drowned prehistory

Archaeological sites and traces of Europe’s landscapes formed at low sea level during the last Ice Age can survive beneath the seabed – but recovering the evidence poses formidable technical and financial challenges.

Now archaeologists, heritage managers, geoscientists and industry representatives have joined forces to research and manage these submerged landscapes that tell the stories behind human evolution.

Although sea level change has become more significant with the threat of global warming, marine archaeologists say the changes humans face in coming centuries are nothing compared with those that occurred in the past.

The melting of ice following the end of the last Ice Age led to a 130-metre sea level rise, reaching present-day levels 6,000 years ago and drowning almost half of the present European landmass previously exposed by low sea levels.

The now-flooded territories were primary areas for human settlement and could provide unique archaeological and environmental data on key transformations in human social evolution.

These include the development of seafaring, fishing and coastal migration, past sea-level and climate change, and the impact of these often-dramatic changes on human societies.

A project titled Submerged Prehistoric Archaeology and Landscapes of the Continental Shelf has begun under the European Cooperation in Science and Technology group, known as COST, to bring more than 100 archaeologists, marine geoscientists, palaeo-climatologists, cultural heritage managers and representatives of industrial companies together from 25 European states.

The group is based on networks called COST Actions, and centres on research projects in fields of interest to at least five COST countries. These cover basic and pre-competitive research as well as activities of public utility as part of the ‘Lisbon objectives’.

The marine archaeology research has fostered the establishment of a pan-European digital mapping of underwater sites, enabling a more detailed understanding of the archaeological data preserved on the seabed.

A group of researchers is associated with the Dutch Cultural Heritage Agency to collaborate with the Port of Rotterdam Authority and with geoscientists and archaeologists from the Rotterdam Archaeological Research Office and the Deltares Research Institute. The aim is to investigate submerged evidence of life in the Ice Age in areas in and around the port.

The large quantities of bones from ice-age mammals and occasional stone artefacts caught up in the nets of trawler fishermen have long shown the presence of drowned prehistoric archaeology on the North Sea floor.

Plans announced by the Rotterdam authority for the construction of a new harbour, requiring dredging 240 million cubic metres of sediment to a depth of 20 metres raised the prospect of conducting archaeological research.

Drilling sediment cores in target areas revealed a site of the mesolithic period, dated to 12,000 to 6,000 years ago, under one of the harbour floors that would be destroyed by dredging. Innovative technical solutions were devised to excavate relatively large volumes of sediment to rescue some of the archaeological data.

Remnants of mesolithic sites were discovered in three locations at a depth of 17 to 21 metres and radiocarbon-dated to 9,500 years ago. The excellent preservation under water resulted in finds of bone, charcoal, wood and plant material, as well as stone artefacts, providing unusually detailed evidence of environment and early mesolithic palaeo-economy.