Excavation

Excavation is one of the most commonly known and used techniques of archaeological investigation. It involves the systematic removal of data from the ground. Excavation provides the most complete evidence for human activity during a particular period and how these activities changed over time. There are many approaches to excavation, but at its most basic, the method involves looking at activities horizontally in space and vertically through time.

By its very nature, excavation is a destructive and costly process. It is an unrepeatable experiment that requires precise methods of data extraction and recording. Before excavating a site, it is essential to understand how sites are formed. Sites are what remains from settlements and other structures. The residues of a past social system will change over time due to decay, erosion, robbing, and the effects of plant and animal action. It is thus important to recognize these processes and distinguish them from the past actions that led to the creation of the site.

To understand this, it is essential to understand the principle of stratigraphy. This is a geological principle that states that layers of strata are laid down according to processes: The layer at the bottom is the oldest layer, while the topmost layer is the most recent. This is called the law of superposition. Understanding this process is crucial for interpretation and dating purposes.

The archaeologist, then, must carefully remove and record each layer and understand the stratigraphic sequence. He or she must be able to recognize how the process works. For example, a pit dug from a higher into a lower layer may lead to later materials being found in lower levels. Strata can also become inverted; for example, a series of strata can be eroded [Page 929]to the bottom of a valley. To this, one must add what Michael Schiffer calls “N-transforms,” natural processes which affect the archaeological record, for example, burrowing by animals and seismic activity. Changes brought about by humans are called “C-transforms” (cultural transforms).

Source: © iStockphoto/Tina Rencelj.