Introduction

What Is an Archaeological Site?

Archaeological sites are locations where former human activity is manifested. Possible evidence of events within sites includes structural features, artifacts, macro-, and microscopic flora and fauna, as well as molecular evidence such as lipids, DNA, and stable isotopes. Conservation and protection of sites may be required either before or after excavation. The abundance of archaeological sites, changing patterns of financial resource, and ever-improving investigative scientific techniques mean that modern archaeological resource management, particularly in Europe and North America, seeks to preserve sites with minimal intervention rather than by excavation.

Conserving archaeological sites requires an understanding of what is likely to survive within them and how these materials interact with their environment before and after excavation. Site formation processes will dictate the survival of buried archaeological-sites and the evidence they contain. Cataclysmic events such as the eruption of a volcano or inundation by silt-laden floodwater normally provides exceptional survival of evidence, but gradual abandonment of sites provides poorer survival of structural, artifactual and ecofactual evidence. Between these extremes exists a wide range of survival possibilities.

The quality of evidence extractable from decayed buried material will depend on the chemistry of the ground environment and the degree of physical protection afforded to site structures. Material decay is expected to be initially rapid on the ground surface, but slows in the changed environment provided by burial. Rate of decay will be dictated by the prevailing burial conditions, which may often favor very

Slow decay; this is not the state of equilibrium previously postulated. Sometimes decay during burial is stopped by the absence of an essential decay parameter, like oxygen or water; again this is not true equilibrium. Subsequent changes in ground conditions will influence the stability of a buried material and excavation will return objects to a state of rapid change and decay. Leaving archaeological materials undisturbed in the ground normally offers them a better chance of survival than excavation if there is no provision for their ongoing conservation and curation.

Provision for Protecting Archaeological Sites

Conservation of sites begins with an understanding of their material needs and the protection of the law. Although there is no overarching legal protection for archaeological sites, there exists a body of international charters promulgated by UNESCO and the International Council on Monuments and Sites (ICOMOS), such as the Venice Charter of 1964 that sets standards for the protection of sites and monuments and the Lausanne Charter of 1990 that focuses specifically on the protection and management of archaeological heritage. At a national level, an increasing number of countries are bringing in regulations designed to protect sites from the effects of development. The English Planning Policy Guidance Note 16, Archaeology and Development, for example, emphasizes the need to mitigate the impact of a development on the prevailing archaeology.

Too Many Archaeological Sites to Preserve?

The archaeological record will always pose pragmatic questions for society and government. In many countries the sheer abundance of archaeological sites begs the question: can all sites be preserved? In situ preservation is a possibility once the ground environment of a site is known. The goal of this strategy is to minimize the impact of changed land use or modern development on the buried archaeology. International charters such as the UNESCO Lausanne Charter and national policies such as the Planning Policy Guidelines of the United Kingdom, favor preservation in situ and minimizing the effects of development over whole-scale excavation.