Saturday, June 18, 2005


Archaeology under the North Sea


June, 16, 2005

The DTI has published a page of downloadable archaeology reports, as part of its SEA (Strategic Environmental Assessment) process prior to licensing for offshore energy developments.

The reports include maps for the known and likely occurrence of prehistoric archaeological remains across the whole floor of the North Sea, as well as evidence that the Orkney-Shetland Ridge, may have been dry land over 5000 years ago.

The existence and possible survival of prehistoric sites is complicated by the rapid and continuing uplift of the east coast of Scotland and the immediately adjacent shelf in the Moray Firth, the fact that ice sheet covered part of the seabed obliterating most artefacts earlier than about 20,000 years BP, and that the seabed towards the median line has subsided, and was associated with extensive sea-water lakes and floating sea ice during the glacial maximum.

The combination of post-glacial sea level rise which terminated about 5000 years ago, and the continuing subsidence of the outer shelf, with uplift of the mainland, creates a complex sequence at coastal sites, some of which may have been dry land over 5000 years ago, then covered by the rising sea, and are now uplifted again relative to a constant sea level.

Known submerged prehistoric sites in Orkney, Shetland, Viking Bank, the Yorkshire coast, and Denmark, show that prehistoric sites from the last 5-10,000 years can survive marine transgression. The strong current conditions in the SEA5 area, the exposure to North Atlantic storms, the thin sediment cover in many places, and the large areas of exposed bedrock, make the exposed areas of the shelf statistically poor prospects for the survival of prehistoric deposits in situ, other than in submerged caves and gullies.

Within sheltered sea lochs and enclosed bays of the east coast of the Shetlands, Orkney and Fair Isle, in submerged gullies, and locally thick sediments, survival is quite likely. Deposits in open shelf gullies are likely to have been transported and re-deposited.

Evidence from the northern North Sea and the Russian Arctic suggests that some prehistoric peoples may have occupied the exposed shelf area during late glacial periods utilising Inuit-style survival methods, and butchering marine mammals. If this proves to be the case, there may be unexpected occurrence of earlier prehistoric sites, Late Palaeolithic, on the north-east shelf.

Pipe entrenching is the process in the oil and gas industry which is most likely to disturb prehistoric archaeological deposits. Commercial site investigation using acoustics and coring could provide beneficial new archaeological data.

The paper concludes with tentative suggestions for discussion of protocols and a reporting regime.


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