In Situ Preservation as a Dynamic Process: The Example of Sutton Common, UK

Article excerpt

Introduction

The need for long-term in-ground protection of the archaeological resource, or in situ preservation, is a stated objective of national and international agencies concerned with the future of the archaeological resource. This is asserted in English Planning Policy Guidance 16, `Archaeology and Planning' (Department of the Environment 1990), by the Council of Europe in the Valetta Treaty (e.g. Willems 1998) and by the United Nations agency, the International Council of Monuments and Sites regarding the marine archaeological resource (ICOMOS 1996). Kenward & Hall (2000) recently highlighted the problems of in situ preservation within wet deposits by presenting the example of delicate organic remains in urban York. Evidence from insect remains in archaeological deposits demonstrated the possibility that there is widespread decay that has been initiated recently. The potentially unstable nature of the buried remains was also presented, and the lack of `properly funded' research into the problem of in situ preservation and in-ground decay was blamed.

Kenward & Hall commence a debate that is fundamental to the future of the archaeological and palaeoenvironmental heritage. We wish to develop some of their arguments, by looking at several basic characteristics of in situ preservation, the importance of site management and the need to develop a `science-based' approach to in situ preservation. We present the example of Sutton Common, an Iron Age site with variable preservation of waterlogged remains, located c. 40 km to the south of York. Here, we are providing the scientific input and advice in a large-scale experiment co-ordinated by the landowner in co-operation with a range of key organizations. The project is aimed at preserving parts of the organic archaeological resource, involving an integrated and dynamic process of monitoring and modelling the burial environment within the context of providing a combination of environmental, archaeological and community benefits.

In situ preservation as a dynamic process

Whether in situ preservation is achievable or not requires the aims to be placed within a contextual framework, e.g. the different types of material and information that are to be preserved. Kenward & Hall note that certain types of materials may be preserved to a greater degree than others, e.g. labile material is more prone to decay than robust remains. From this it may be understood that complete in situ preservation is unattainable due to partial decay at the time of deposition, but that it is possible to preserve certain materials indefinitely. At a lower resolution, the possibilities for in situ preservation may be understood in relation to different archaeological features within a site. For example, variable soil processes within pits will create different localized burial environments that influence the potential for the longterm preservation of material contained within, a phenomenon known to any archaeologist involved with the excavation of a well. Similarly, the likelihood of preservation of organic archaeological sites may be closely associated to their function and location. For example, the prehistoric trackways on the foreshore of the Humber estuary were built to allow crossing of intertidal creeks, and their rapid incorporation in the anoxic muds enabled excellent preservation (Fletcher et al. 1999). At the site level, it may only be possible to preserve certain areas due to a number of factors, not least the size of the site itself and its location. It appears that in situ preservation may only be usefully attempted within the context of resolution and an understanding of the material to be preserved.

The perception that archaeological remains can be preserved in situ without any form of management is unsustainable, a point that emerges clearly from Kenward & Hall's paper. A wide variety of environmental changes will impact on the burial environment of any archaeological monument. …