Investigations of deep, submerged Stone Age settlements covered by sea-floor sediments: Preliminary methodological considerations

In the light of the increasing industrial activity in the oceans, management of the submerged cultural heritage beyond the shallow zone is becoming a matter of increasing concern. National legislative bodies, together with the 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage, underline the need to develop a legal and methodological framework for management of the submerged cultural heritage. Besides ship wrecks, which are numerous, Stone Age settlements likely represent the dominant type of submerged cultural heritage sites requiring competent and cost-effective management. As the average sea level during successive glaciations was, for long periods, more than 100 m below that of today, and as the subsequently submerged areas appear to have been more intensely inhabited than hitherto imagined, it seems logical to expect well-preserved remains of early human settlement to be associated with these highly productive prehistoric coastal areas. The archaeological finds recorded demonstrate that this settlement, even in Northern Europe, extends back as far as 1 million years. A pre-requisite for a successful implementation of future legislative initiatives is the development of a technical basis consisting of 1) cost-effective methodologies for mapping and investigating the submerged Stone Age sites and 2) cost-effective methods for investigating/excavating the deeper submerged Stone Age sites. This study addresses the latter point because it is seen as being important to facilitate an interactive development of legislation and the possibilities that technological advances in underwater acoustic sensing, positioning, robotics and mechatronics can provide. For example, it would presently be quite problematic to have to carry out an investigation of a well-preserved mammoth-hunter site covered by 5 m of sediments and located at a depth of 70 m. How should one excavate such a site at a reasonable quality level? It is likely that we may have to de- l with situations of this type in the near future. This paper discusses how the maximum amount of information can be obtained about such sites during a pre-excavation evaluation stage by physical characterization of cultural and surrounding layers and sediment/dirt DNA analysis, etc, as well as the possibilities for on-site excavation or, alternatively, the extraction of blocks of sediment for excavation under controlled conditions during an actual investigation.