OPEN:Fading Star - Shining light: Integrating an evidence-based decision support system for in situ preservation of waterlogged archaeological remains

Across the UK and Europe, a policy of preserving an archaeological site in situ (leaving it unexcavated) for the benefit of future generations is widely pursued, according with UK and EU government planning policy. However, recent research, notably a NERC-funded project focused on the Mesolithic site of Star Carr, indicates that this policy is not always advisable. In some cases, changing environmental conditions may accelerate the decay of organic remains such as bone and wood left in situ.

Waterlogged sites are most at risk, as they are more susceptible to environmental change; however, these are also the sites that contain an abundance of organic materials, which aren't preserved at other sites, making them valuable cultural assets. In the UK, examples of archaeologically significant waterlogged sites are abundant, and include Sweet Track (a prehistoric wooden trackway across the Somerset levels) and Must Farm (a Bronze Age site where recently numerous rare log boats have been excavated, and a wooden wheel, described by the excavators "unprecedented in terms of size and completeness").

A wealth of research into the factors contributing to successful in situ preservation has been carried out in both academic and cultural management sectors throughout Europe. Through this research it has become clear that a comprehensive assessment of potential environmental risks to a site, and the state of preservation of organic artefacts should be carried out prior to deciding how an archaeological site should be managed. However, there is currently a lack of standardisation of how this assessment is conducted.

The NERC-funded "Fading Star" PhD CASE studentship developed a number of cheap, easily applicable and informative tests by which organic preservation could be assessed and monitored. Levels of deterioration were then consolidated with geochemical data, allowing the effects of site geochemistry on organic preservation to be determined The aim of this proposal is to enable those tests to be utilised by the wider archaeological community to assess the preservation potential (and recognise rapid degradation) of other waterlogged sites.

Key to the success of this fellowship is working closely with Historic England, who currently provide guidance on preservation in situ, and archaeological field units, who undertake developer-funded assessments and excavations. This will allow the knowledge gained from the study at Star Carr to be successfully translated to people who work directly with archaeological excavations (ranging from archaeological professionals to volunteers), so that all relevant information can be taken into account both during and after excavations.

The principal outcome of the project will be the development of a decision-making tool that not only incorporates new and existing knowledge amalgamated from past and ongoing research projects, but also the wealth of knowledge from archaeological practitioners. This system will guide the user to make an assessment of the archaeological significance, possible environmental and geochemical risks to a site, and assess the current levels of organic preservation. This data will then be translated into realistic advice on how best to proceed with management of the site, whether it be to preserve in situ with or without a monitoring programme, conduct further investigations, or to proceed with a 'rescue excavation'. The assessment can also be used to recommend where attention should be focused post excavation; for example which artefacts need immediate conservation to prevent further decay and loss of archaeological information.

The availability of this tool directly addresses a recognised need to standardise the steps taken to successfully safeguard archaeological sites against changing environmental conditions, resulting in the preservation of our precious archaeological assets for future generations to both study and enjoy.