Archaeological sites are formed in a variety of ways called site formation processes by archaeologists. An archaeological site is the place where traces of past human activities are found. Based on these activities, artefacts are eventually deposited in the ground and, later, are often disturbed. Some sites were used for a very brief period in time, others for thousands of years. Archaeologists generally classify the sites according to the type of activity that occured there: a burial site, a settlement site, a kill site, a religious site, etc…
Here are different types of site formation processes:
* Discard/disposal: this can be a casual discard (tossing something) or disposal in dumps or pits (think of a city dump…);
* Intentional burial: there are two types of intentional burials, the first is burial for later retrieval (think of food in storage pits) or the other, burial not intended for retrieval (think of graves for the deceased);
* Abandonment: we can all picture in our mind people leaving a village or a building and never to return.
Natural Disturbance Processes
* Catastrophic burial: think of a settlement covered by lava and volcanic ashes [the site of Pompeii is a good example of that], a sand dune or even a mudslide/rockslide;
* Bioturbation: this is caused by tree roots or animals (like rodents and even earthworms) disturbing the soils by digging tunnels and burrows, which eventually lead to soil instability;
* Cryoturbation: in this case, soils are disturbed by freezing and thawing;
* Erosion: the wearing away of rocks and soils by the action of wind, water, ice.
The first thing that needs to be remembered is that without human activity, there wouldn’t be archaeological sites. The acting out of a specific activity at a location chosen by humans for a certain amount time is how an archaeological site is primarily formed. As an example, think of a cemetery. A cemetery is a location chosen by humans to perform a specific action, to bury their dead. The site was formed because people dug holes in the ground, placed the deceased along with funerary goods in it, and covered it up again.
However, there is much more to site formation than just human activity. Human activity is the first step to site formation, but sites will likely be disturbed by a variety of factors over the centuries and that’s how archaeologists will find most sites, disturbed.