Survival of Artifacts

When considering the history of artifacts and their development at different times and in different places, it is important to appreciate how few of the artifacts used by our ancestors have survived to be found today. All artifacts are subject to decay, but the speed at which they decay depends on the materials from which they are made and the environment in which they are left. Some of the decay is caused by physical processes such as wind, rain, and sun exposure. Fragile items are particularly susceptible to these processes. Chemical processes also cause decay. For example, iron artifacts rust when exposed to oxygen and moisture and acids contained within surrounding soils dissolve artifacts made from plant and animal products. Biological processes actively decay artifacts made from plant and animal products that attract scavengers, insects, and bacteria.

Survival of artifacts in the archaeological record therefore depends on the extent to which they are protected from all of these elements. Bacteria thrive in moisture, and biological organisms depend on oxygen. Rapid burial or enclosed spaces such as caves, protect artifacts from physical processes (see Caves and Rockshelters; Sites: Mounded and Unmounded). Very dry sites without moisture and places that restrict access to oxygen, such as bogs and frozen sites (see Frozen Sites and Bodies; Sites: Waterlogged), protect organic artifacts.

Sometimes artifacts survive because people in the past have taken steps to deliberately protect them from decay. Good examples of these are the ancient Egyptian practice of mummification of important people and the protection of their goods by building elaborate tombs. It is important to recognize, however, that such circumstances are exceptional and, although some of the situations mentioned above will protect artifacts for thousands of years, only those artifacts made of the most durable materials will survive for long periods. All of this means that, although our knowledge of the variety of artifacts made and used in the very recent past is relatively complete, the further we go back in time the less likely we are to recover the full range of artifacts made and used by people. In addition, the kinds of artifacts available to investigate the deep past is biased toward only the most robust materials, in particular those made of stone.