disturbance

A disturbance is any change to an archaeological site due to events which occurred after the site was laid down. Disturbances may be caused by natural events or human activity, and may result in loss of archaeological value. In some cases, it can be difficult to distinguish between features caused by human activity in the period of interest, and features caused by later human activity or natural processes. Causes Natural causes The soil scientist Francis D. Hole identified nine natural processes resulting in soil disturbance, including the movements of animals and plants (known as bioturbation, and including burrowing, root growth and treefalls); freezing and thawing; movement under gravity (including earthflow and rockslides); swelling and shrinking of clays; the actions of wind and water; the growth and dissolution of salt crystals; and movement caused by earthquakes. Different sites are subject to different degrees, combinations, and interactions of these processes, and archaeologists working with a given site must be familiar with the processes in play at that site to avoid the risk of misinterpretation.