The inspiration for the Happisburgh and Pakefield exposures project came from the unique opportunity to trace very early sediments of known archaeological potential offshore into the marine environment. The fine-grained sediments onshore are unique and have changed our understanding of the earliest occupation of Britain. Finds within these sediments have demonstrated that human occupation of northwest Europe may date to c. 700,000 BP rather than c. 500,000 BP as previously thought.

The survival of these deposits at the base of the cliffs at Happisburgh and Pakefield is unexpected considering their character and nature, and the series of geomorphological processes that have affected them. As these deposits reside at the base of the cliff line and on the foreshore there is a possibility for their survival offshore.

Cliff exposures at PakefieldDemonstrating the survival of pre-Devensian fine-grained sediments offshore will radically alter the interpretations for very early prehistoric material in the seas around the UK, and therefore change the advice given to aggregate companies in the course of licence applications.

The method for this stage has involved geophysical survey, comprising bathymetric, seismic and sidescan surveys of areas off the coast of Happisburgh and Pakefield. Based on preliminary interpretations of the geophysical data, a further variation to the project was developed. This involved a geotechnical (vibrocore) survey at three locations identified from the geophysical data at the Pakefield site.

Geophysical survey

At Pakefield, the cliff exposure sediments comprise units of Cromer Forest-bed Formation overlying Wroxham Crag Formation sediments. The Cromer Forest-bed Formation cannot be traced offshore based on the data from the geophysical survey, though sediments interpreted as being part of the Wroxham Crag Formation were identified. It is possible that the Cromer Forest-bed Formation is preserved between the foreshore and the western limit of the study area. Offshore, it is considered that any sediments of the Cromer Forest-bed Formation that were deposited have been removed during either the Anglian glaciation or subsequent marine transgressions and regressions.

At Happisburgh, the survey was carried out further from the coast in deeper water to that of Pakefield due to the presence of beach groynes that posed a risk to the equipment. Only sediments interpreted as older than those identified in the cliff exposures and on the foreshore were identified on the geophysical data. However, it is possible that younger sediments relating to the Cromer Forest-bed Formation observed on the foreshore and related early Middle Pleistocene sediments may be preserved closer to the shoreline.

Geotechnical survey

Deploying the vibrocorerA total of five vibrocores were acquired from three locations identified from the geophysical data at the Pakefield site. The purpose of these cores was to confirm and add detailed information on the stratigraphy observed from seismic survey and to provide environmental samples. At two of the three site locations, cores were specifically taken for Optically Stimulated Luminescence (OSL) dating.

Geoarchaeological analysis

Vibrocore VC-P2Vibrocore analyses enhanced the geophysical data interpretation and enabled a better understanding of the sediments and sediment deposition environments. This enabled correlation between onshore and offshore sediments. Although sediments of the Cromer Forest-bed Formation no longer exist offshore, older sediments interpreted as the Wroxham Crag Formation were identified. It was within the upper part of the Wroxham Crag Formation that worked flint was found onshore. The survey at Pakefield successfully demonstrated that sediment units identified onshore can be traced offshore and that not all of these very early terrestrial sediments that are now in submerged areas have been removed by glacial processes and/or marine erosion.

Environmental analysis

Pollen, diatom, foraminifera and ostracod subsamples have been taken from two vibrocores. These samples are currently being assessed in order to provide environmental information, biostratigraphic correlation and possible dating evidence from the described sedimentary sequence.