Project Methods
Finding a good excavation site:
A complete excavation is a lot of work! Excavations take a lot of time and effort. It is important for archaeologists to plan to dig at sites that have a high possibility of revealing important information that speaks to the project they set out to complete. There are a few ways to find a site that is worthy of excavation:
Controlled surface collecting means using a system (usually grids) to map and collect artifacts at the surface of recently plowed fields. The resulting maps and points where artifacts were found point out where human artifacts are found, some of which can date back thousands of years.
Shovel testing is when archaeologists dig holes (40 centimeters in diameter, and 30 to 100 centimeters deep) several meters apart around the site. Digging up a whole site, that can be the size of a football field, is unrealistic! The findings from the STP’s (Shovel Test Pits) are mapped and reveal clusters of artifacts. These clusters can direct archaeologists to where they should dig further to reveal significant findings.
Metal detectors determine the distribution of metal objects in the soil. Most of these turn out to be nails, so if there are many nails in an area, there is a good chance that this was once a structure, and a great place to dig.
A magnetometer detects a magnetic “signature” in the soil, rather than individual objects. If the area only has one signature, it hasn’t been disturbed and won’t make for an interesting dig site. But, if the magnetic signature changes across an area, there is a chance the soil was disturbed by human activity. Selecting this site for an excavation could reveal the foundation of a building or a fence post.
Each of these methods can help identify archaeological sites. Identifying a site of interest is important to archaeologists. We care about finding places that can provide the kind of data we need to help answer our research questions. It’s also important to us to find how much of the site we will need to excavate to answer those questions.
Excavation:
Performing an excavation, by its definition, destroys the site. When digging through the ground and removing artifacts, we change the natural stratigraphy and position of the artifacts we find. It is very important that we keep accurate written and photographic records throughout the excavation so that irreplaceable information will not be lost. A site cannot be dug twice! Once the artifacts are removed, their exact positions cannot be replicated.
Here are some of the methods we use when excavating our units.
Dig out units by 2 by 2 by 0.4 meters with shovels.
Sift the soil. The soil we dig from the units is screened through large sieves that sit on wooden frames about the size of a laundry sink. Volunteer scientists shake the sieves and sort through the remaining sediment in search of artifacts.
Wash the artifacts to be able clearly identify. Small markings on artifacts are critical to identification of a time period or origins of the artifact.
Organize and catalog the artifacts. The scientists and volunteer scientists work to sort artifacts into types, such as metals, ceramics, or animal remains so they can be easily accessed, examined, cataloged, and analyzed.