Seabed Prehistory: Area 240

Between 2008 and 2011 Wessex Archaeology conducted a detailed and far reaching study in aggregate licence Area 240, which is situated approximately 11 km east of Great Yarmouth in Norfolk. The project, entitled Seabed Prehistory: Site Evaluation Techniques (Area 240), built on the work of Wessex Archaeology’s Seabed Prehistory project.
 

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The Area 240 project, which was funded by the Aggregate Levy Sustainability Fund (ALSF) through English Heritage, was initiated in response to the discovery in February 2008 of 88 flint tools and associated faunal remains amongst aggregate from dredging licence Area 240. Initial assessment of the flint tools indicated that they were Lower or Middle Palaeolithic. These finds represent one of the most significant discoveries of Palaeolithic material from the North Sea as the quality and quantity of the artefacts suggests that a number of them had lain undisturbed since their deposition.
 
Prior to this discovery, it was generally thought that deposits of this date had been destroyed or disturbed by glaciation and subsequent sea level rise. The discoveries from Area 240 suggest that in certain areas at least, some of this earlier material still survives under the sea.
 
This project fully investigated Area 240 in order to test, develop and refine techniques for exploring our submerged prehistory. By employing these techniques in the future we can hope to locate, explore and protect further sites of Palaeolithic significance in our waters.
 
Looking towards Lowestoft from Area 240Looking towards Lowestoft from Area 240
 
To find out more why not purchase the publication here.

 

Background

Marine Aggregates at a wharfMarine Aggregates at a wharfThe marine aggregate industry provides approximately 21% of the sand and gravel needed for construction projects around the UK. Whilst every licence area is subject to detailed archaeological study prior to the granting of the licence to dredge, industry staff regularly find archaeological material amongst aggregate loads. Wessex Archaeology implement a reporting Protocol for members of the British Marine Aggregate Producers Association through which such material can be reported and investigated.

 
In February 2008 Hanson Aggregates Marine Limited reported the discovery of 88 flint tools – including handaxes, flakes and cores – and the remains of mammoth, rhinoceros, bison, reindeer and horse. These finds were discovered at SBV Flushing wharf in Holland where material from Area 240 was discharged. Their finder was local palaeontologist Jan Meulmeester, who regularly searches the heaps at the wharf for archaeological and palaeontological material, such as animal bone. His searches were assisted by the wharf manager Henk Strijdonk.
 
Area 240 findsArea 240 findsDespite having been found on a discharge heap, the provenance of the finds is well understood. It has been possible, by comparing the dates of Mr Meulmeester’s visits and the GPS trackplot of the dredging vessel’s progress, to locate the site of the finds to within a 3 x 1 km area within licence Area 240.
 
The discoveries from Area 240 have attracted international attention and, in November 2008, were awarded a prestigious British Archaeological Award. The flint implements were the subject of a research project at the University of Leiden in Holland carried out by Dr Dimitri de Loecker, whilst the faunal remains were catalogued and analysed using radiocarbon dating by Jan Glimmerveen, also in Holland.
 
Once it was established that the material had been dredged from Area 240, the aggregate area licensee, Hanson Aggregate Marine Limited, voluntarily placed a protective exclusion zone around that part of the seabed from which the cultural material was dredged.

Aims and Objectives

One of the handaxes discovered from Area 240One of the handaxes discovered from Area 240This project has three core aims.
 
The discovery of the artefacts from Area 240 significantly changed archaeologists’ understanding of the potential for prehistoric material in aggregate dredging areas in the North Sea. Although the potential for prehistoric material to be present was widely endorsed, and had been the subject of numerous investigations and research, actual numbers of discovered artefacts were low.
 
The discovery and reporting of the Area 240 finds offered the rare opportunity to conduct a detailed study to establish the geological and geomorphological context of the recovered finds and to attempt to locate further artefacts.  Situated in water depths of approximately 25 metres, and in an area with strong tidal currents and poor visibility, the investigation of Area 240 proved challenging.
 
The principal aim of the project was to improve the future management of the effects (and potential effects) of aggregate dredging on the marine historic environment. There were three objectives to the project. Firstly, to refine practical techniques used to establish the presence or absence of prehistoric archaeological material (artefacts, deposits, faunal and other palaeoenvironmental material) on the seabed and to establish the character, date, extent, quality, preservation and special interest of such material, if present. Secondly, this project aimed to provide a firm understanding of the area from which the finds were dredged and in turn provide greater insight into the historic environment of this region as a whole. 
 
Wessex Archaeology is a charitable trust dedicated to education. The final aim of the project is to pass on the knowledge gained throughout this study to both public and professional audiences. To learn more about how the results of the project were disseminated publicly, visit the Time Travelling by Water website.
 
Pupils at Edward Worlledge school get to grips with archaeologyPupils at Edward Worlledge school get to grips with archaeology

The Project Method

Between 2008 and 2011 a number of investigations were undertaken following two main strands of research. The geology context of Area 240 was studied which included a detailed re-examination of geophysical and geotechnical data from industrial surveys, intensive geophysical survey of the area from which the artefacts and faunal remains were dredged, coring to obtain samples of the sedimentary sequence within Area 240 and accompanying palaeoenvironmental assessment and analysis and the scientific dating of 12 samples. The second strand of investigation involved sampling the seabed for archaeology, animal remains and palaeoenvironmental material using existing techniques. The sampling exercise was conducted to assess the suitability for seabed sampling methods in order to observe this material, and their spatial distributions. 
 
Monitoring equipment on board the survey vesselMonitoring equipment on board the survey vessel
 
The results of each stage of the project are available from the Archaeology Data Service (ADS) ALSF archive.
 

Stage 1 & 2

 

Geophysics

Deploying geophysical equipmentDeploying geophysical equipment

Stage 1 involved the review of existing geophysical and geotechnical data that was collected for Hanson Aggregates Marine Limited over the last decade. This review aided our understanding of the geology of the area and helped to place the results of detailed investigation (Stage 2) in their wider context. During this stage a total of 420 line km of geophysical data and 109 vibrocore logs were assessed and interpreted.
 
The second stage of the project involved the acquisition and processing of geophysical data of the 3 x 1 km area where the handaxes were recovered. The aim of the survey was to acquire a more detailed dataset and to assess the different sub-bottom profiler seismic sources for targeting aggregate deposits. The acquisition of the new dataset also established the condition of the area since dredging had ceased and to assess changes in surface and sub-surface sediments compared to the previously acquired 2005 dataset.
 
 
 
 

 

Stage 3

 

Seabed sampling

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Stage 3 of the project involved a programme of seabed sampling with the aim of establishing the presence of any remaining archaeological material since the original discovery. Three sampling techniques were trialled: clamshell grabs, still photographic survey, and beam trawl. Further animal remains and flint artefacts were recovered using the clamshell grab from a particular region of Area 240. These results have led to a significant improvement toward our understanding of the character of the historic environment in the region.

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Stage 4, 5 & 6

 

Palaeoenvironmental sampling, analysis and dating

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Stage 4 involved the acquisition of vibrocores at ten locations within the Area 240. The vibrocores targeted sediment units that would provide palaeoenvironmental material and allow for the assessment, dating and reconstruction of the former land surfaces within Area 240. Assessments were based on the on-going interpretation of geophysical and geotechnical data from Stages 1 and 2.

Samples from four vibrocores were assessed for macro-botanical (plants and charcoal), macro-fauna (molluscs and insects), micro-botanical (pollen, diatoms and micro-charcoal) and micro-fauna (ostracods and foraminifera). Additionally, a series of samples were dated using radiocarbon and Optical Stimulation Luminescence (OSL) dating techniques.
 
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Stage 7 & 8

 

Synthesis, dissemination and outreach

Time Travelling by Water logoTime Travelling by Water logoThis stage involved a desk-based exercise which focuses on synthesising the results of the project and addresses both the technical developments achieved by the project and the characterisation of the seabed prehistory that has been achieved.

 
As part of this stage a number of school visits, event days and web based dissemination tasks were undertaken. In June 2009 school workshops were delivered to Year 5 and 6 pupils in four different schools in Great Yarmouth and Pakefield and community group talks were presented. 
 
The Royal Norfolk Show was attended on the 1st and 2nd July 2009. Over 1,000 people of all ages visited the stand to learn about submerged prehistory and the Area 240 project. The Lowestoft Airshow was also attended on the 23rd and 24th July where display panels detailing the project were displayed alongside examples of finds from the area. 
 
Display panels detailing the project were displayed at the Time and Tide museum in Great Yarmouth, during October 2009. The museum has strong links with local schools and organisations and is very well known in the Norfolk region. It features a prehistoric gallery that introduces some of the themes explored by the Area 240 project. 
 
Additionally, both the project methodology and results have been presented to a wider audience through a series of conference and seminar papers and posters. The audience have included industry and regulators as well as the research community.
 
Time Travelling by Water at the Norfolk ShowTime Travelling by Water at the Norfolk Show
 

Subsequent work

The Area 240 project was complete by March 2011 and the results of the project synthesised into a final project report. However, work on the palaeogeography of the region has since continued. 

Following the conclusion of the Area 240 project discussions continued with Hanson Aggregate Marine Limited regarding the remaining potential for artefacts in Area 240. Questions remained over the extent of the archaeological material, particularly the flint artefacts.
 
In 2011 Wessex Archaeology were commissioned by Hanson Aggregate Marine Limited to undertake a programme of archaeological monitoring of aggregate dredging activity on board a dredging vessel and at the receiving wharf at SBV Flushing. The project trialled the method of sampling large volume of sediment for archaeology, using standard aggregate dredging equipment. The recovered archaeology helped to evaluate the distribution, character, quality and preservation of Palaeolithic artefacts within Area 240.
 
In 2012 Wessex Archaeology was commissioned by the British Marine Aggregate Producers Association on behalf of The Crown Estate, CEMEX UK Marine Limited, Hanson Aggregates Marine Limited, Tarmac Marine Dredging Limited and Volker Dredging Limited (the East Coast aggregate block licensees), to conduct an assessment of the Palaeo-Yare catchment area, East Anglia. The aim of the project was to map the extent  and survival of the specific sediment units from which a large number of flint artefacts and faunal remains were recovered in Area 240. 
 
Approximately 2,500 line kilometres of sub-bottom profiler data (from 22 surveys) and 1,171 vibrocore logs (from 43 separate surveys acquired between 1988 and 2011), were reviewed. The majority of these logs were from sampling originally undertaken by the marine aggregate industry. Additionally, approximately 400 onshore borehole logs (supplied by BGS) were reviewed, providing further context.

Landscape

The sub-seabed sediments observed in Area 240 are an offshore extension to the Palaeo-Yare river system. The present-day remnants of the Palaeo-Yare valley system includes the Rivers Yare, Wensum and Waveney. The lower reaches of the River Yare and Waveney flow into Breydon Water, the remnants of an outer estuary, and flows east from Breydon Water and then south into the North Sea.

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The reconstruction of Area 240 reveals a complex history of deposition and erosion. The Area is dominated by floodplain and channel-infill sediments deposited in a cold, estuarine environment dating to the Wolstonian some 250,000 years ago near the banks of a large river channel. During the subsequent Ipswichian interglacial, around 120,000 years ago, the Area was submerged as sea levels rose during climatic warming. During the early Devensian (approximately 110 thousand years ago) as the climate deteriorated the river channel was re-activated, recut and infilled with estuarine deposits. The most recent development in the area, prior to being inundated by rising sea level, relates to the development approximately ten thousand years ago of an early Holocene shallow, meandering partially infilled channel comprising intertidal mudflat/saltmarsh sediments. The Area was drowned most recently approximately 8000 years ago.
 
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Artefacts

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In addition to the initial discovery further artefacts were recovered using seabed sampling techniques and during vessel and wharf monitoring of dredge loads. Recovery locations indicate that the artefacts are not confined to a small, isolated zone of Area 240 but are more widespread. A total of 124 pieces of worked flint were recovered from Area 240 during these activities.

The artefacts were primarily recovered from the Palaeo-Yare floodplain sediments deposited between 200,000 and 250,000 years ago. The worked flint type and condition of the artefacts indicate that they were deposited in different conditions – some are in pristine condition and some are more weathered – but are likely to be associated with the same sediment unit. 
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The early Middle Palaeolithic artefacts from Area 240 have survived multiple phases of glaciation and sea level change. The results have shown that submerged landscapes can contain preserved Palaeolithic artefacts and the investigations confirm that the artefacts are not a ‘chance’ find, but indicate clear relationships to submerged and buried landscapes that, although complex, can be examined in detail using a variety of existing fieldwork and analytical methods.
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Area 240 Exhibition

Seabed Prehistory: Area 240 - Exhibition (View on Scribd)