The Great Yarmouth study area was selected as one of the new areas in which to trial the Seabed Prehistory project methodologies as it represents an aggregate dredging area with a different geological setting, and as such different archaeological potential, to areas previously surveyed during the course of the project.

Previous work in this area has highlighted peat and clay deposits close to the seabed occurring as part of a fine-grained sediment unit closely associated with the aggregate deposits within dredging area 254. These sediments are considered to be infill deposits within the Yare Palaeovalley. The River Yare was cut prior to the most recent marine transgression and is known to have extended offshore during periods of lowered sea level. Gravel deposits within area 254 could possibly contain reworked archaeological material including flint tools. Five flint implements of Palaeolithic date are known to have been found along the coast near Great Yarmouth. These records (based on a SMR data search) relate to finds of single stone tools, none of which are specifically dated to the Lower or Middle Palaeolithic.

A geophysical survey was conducted in the south-western corner of dredging area 254 (currently licensed to United Marine Aggregates Limited), approximately 10km to the east of Great Yarmouth. Survey work was carried out between August and October 2005. Based on the geophysical data, a geotechnical (vibrocore) survey was conducted in July 2006.

Geophysical survey

Bathymetric dataThe geophysical survey involved the acquisition of bathymetry, sidescan sonar and sub-bottom profiler seismic data.

The results of the geophysical survey indicated the presence of a mound feature, predominantly composed of coarse sediments with areas of onlapping fine-grained sediments. At present it is unknown whether this feature is a landform which existed prior to the area being submerged by rising sea levels or if it is a product of erosion caused by rising sea levels.

The deepest sediment unit observed in the seismic data has been interpreted as the Yarmouth Roads Formation; a sediment formation which dates from the Cromerian period (478,000 to 787,000 BP). Throughout the study area the Yarmouth Roads Formation is overlain by a unit distinguished on the seismic data as high acoustic amplitude with irregular and chaotic reflections which have been interpreted as coarse sands and gravels. This structure reflects a high energy depositional environment as a large amount of energy would be required to transport particles of this size.

Geotechnical survey

Deploying the vibrocorerThe vibrocores were targeted at specific deposits so that detailed geoarchaeological interpretation and environmental sampling could be carried out. Geoarchaeological and environmental analysis of those deposits is currently being conducted at Wessex Archaeology’s headquarters in Salisbury. This will enable firmer conclusions to be drawn on the chronological, environmental and archaeological importance of Marine Aggregate Deposits in the Southern North Sea.