In July my colleague Tom Hill welcomed a group of Archaeology students from the University of Birmingham to the Museum. On their tour they were shown some microfossil slides collected by retired Museum micropalaeontologist and current Museum Scientific Associate John Whittaker from various important archaeological sites showing evidence of the first humans in Britain. I've picked out three key sites where the microfossils in the collection help with dating the finds and reconstructing the environment and climate of these first human settlements in the British Isles.
John is an Associate Member of the Ancient Human Occupation of Britain (AHOB) Project. The project is investigating the timing and nature of human occupation of the British Isles, the technology they used, their behaviour, the environment they lived in and the fauna sharing the landscape. The first site I have chosen was investigated well before the 2001 start of the AHOB Project.
1. Boxgrove about 500,000 years ago
This reconstruction is based on evidence from archaeological excavations at Boxgrove, funded by English Heritage, directed by Dr Mark Roberts of University College, London. (Image by Peter Dunn, English Heritage Graphics Team, copyright English Heritage and reproduced with permission).
In 1993 a Homo heidelbergensis shin bone was discovered during archaeological excavations at a sand and gravel quarry at Boxgrove, Sussex. At the time this represented the earliest evidence of human occupation in Britain. Well preserved hand axes and butchered animal bones with flint cut marks as well as two human teeth were also discovered at the site.
Ostracods and Foraminifera collected by John Whittaker from Boxgrove indicate a marine raised beach and a later terrestrial deposit with freshwater ponds below chalk cliffs. The microfossils were able to show that the Slindon Sand was deposited in a wholly marine high-energy environment, whereas the Slindon Silt was deposited in a shallow intertidal environment at the margin of a regressive sea (see image above). This sort of information is vital when interpreting the archaeological finds from the site.
2. Pakefield about 750,000 years ago
It has long been suspected that the Cromer Forest Bed exposed on the coast of East Anglia could contain evidence of human activity. In 2000, coastal erosion revealed river sediments containing flint artefacts. In 2000, these stone tools provided the earliest evidence for people in Europe living to the north of the Alps and the findings were published in the journal Nature in 2005.
The oldest artefacts from Pakefield came from the upper levels of estuarine silts where both marine and brackish ostracods and foraminifera have been recovered. Other evidence from mammal, beetle and plant remains suggests a setting on the floodplain of a slow flowing river where marshy areas were common.
The river sediments were deposited during a previously unrecognised warm stage (interglacial) and the presence of several warm loving plants and animals suggests that the climate was similar to that in present day southern Europe.
The interglacial sediments are overlain by a thick sequence of glacial deposits which include till and outwash sands and gravels. These contain reworked (Cretaceous and Neogene) microfossils transported from the North Sea Basin by glaciers.
This is important information as fossils found in these redeposited sediments could be give false indications as to the climatic setting and dating of the any finds.
The extinct freshwater ostracod Scordiscia marinae has been found at both Pakefield and Boxgrove and is characteristic of the Middle Pleistocene period.
3. Happisburgh about 840,000-950,000 years ago
Reconstruction of the site at Happisburgh by John Sibbick. (copyright AHOB/John Sibbick)
Shortly after the Pakefield discoveries, Mike Chambers was out walking his dog at on the beach at Happisburgh (prounced Haze-boro) and discovered a flint handaxe in sediments recently exposed on the foreshore. This remarkable discovery sparked a major programme of geological and archaeological work at the site that has discovered at least four other Palaeolithic sites at Happisburgh.
One of the sites is even older than Pakefield and pushes the timing of the occupation of Britain back by at least 100,000 years. The key geological formation has since been named the Hill House after the local pub!
A Palaeogeographic map of Britain the in Early Pleistocene (about showing the land bridge between Europe and the position of the Thames and Bytham rivers. (Courtesy of Simon Parfitt and the AHOB Project).
At this time there was a land bridge between Britain and France that would have aided migration of humans from continental Europe. The English Channel was first cut about 450,000 years ago following a major flood from a glacially impounded lake in the position of the present day southern North Sea. The Thames did not follow its current course but flowed further north through Norfolk converging with the ancient river Bytham.
The saltmarsh foraminiferal species Jadammina macrescens has been recovered from Happisburgh and is consistent with interpretations that the site is situated near the mouth of the ancient large river, possibly the River Thames.
The foraminiferal species Jadammina macrescens is common in saltmarsh environments.
Pollen and mammal fossils suggest that the climate was similar to that of southern Sweden and Norway of today with extensive conifer forest and grasslands. The floodplains were roamed by herds of mammoth and horses. Foraminifera like the species Ammonia batavus are particularly useful climatic indicators.
The foraminiferal species Ammonia batavus is characteristic of warmer climates.
The dating of the deposit is provided by a combination of mammoth, horse, beetle and vole finds as well as the Middle Pleistocene ostracod Scordiscia marinae. Work by John Whittaker and the AHOB team at a number of other Pleistocene sites across the SE of Britain has increased the potential of ostracods as tools for dating these sediments.
The microfossil collections from these important archaeological sites deposited here at the Museum are an important example of collections that support the findings of a high-profile project that is regularly in the national news.