Prior to excavation it is important to consider the conservation needs of a particular site and ensure that adequate funds, facilities, and expertise are available. Planning for conservation in the field involves asking about:
1. the kinds of material finds that are anticipated;
2. the types of stabilization or treatment methods that may be needed;
3. the types of supplies, tools, equipment, storage/ packaging materials required to prepare and transport finds from the excavation to the lab; and
4. the storage conditions that will facilitate the longterm preservation of the collections.
Without careful thought to these considerations, disasters may occur when excavators are faced with unpredictable conditions and materials. The preservation of delicate finds, particularly metals and organics, is dependent on their physical environment during burial. The type of soil, the drainage of water, and the climatic conditions at the excavation site will strongly influence the structural integrity and surface appearance of archaeological materials. Understanding the soil also allows for some prediction of the type of cleaning that would be necessary and will facilitate further studies.
Favorable preservation environments for organic materials include the dry conditions of arid deserts where alkaline soils (pH above 7.0) are more common, the oxygen-free conditions of waterlogged sites, the refrigerated and frozen conditions of arctic landscapes, and situations where generally exclusive and abundant amounts of salt or metallic minerals surround the artifacts. Under these otherwise hostile conditions, organic objects or details from them are often preserved.
Poorer preservation environments include saline soils where seawater is present or in dry environments where flooding or irrigation has been a common occurrence. Acidic soils (with a pH below 7.0) that are associated with areas of high rainfall and the incomplete breakdown of organic matter also contribute to the deterioration of many types of materials (Table 1).
World History
