This week marked the beginning of our 2014 excavation season. Instead of loading up our shovel boxes and heading to Mound House, we have been given the opportunity to investigate another site. This archaeological site, known as 11C120, is unique among the other prehistoric sites in the region as it comprises an earthen embankment surrounded by a ditch. While these earthen enclosures are ubiquitous at contemporaneous sites in Ohio, 11C120 is the only site of its kind in the lower Illinois valley and possibly the entire state of Illinois.
In December of 2013, CAA Director of Research Jason King and CAA Research Associate Jason Herrmann led a team of volunteers in collecting geophysical data across most of the site. A Bartington dual fluxgate gradiometer (magnetometer) provided the largest areal coverage, with additional testing done using a ground penetrating radar (GPR) unit and an earth resistivity meter targeted on key portions of the site.
The results of these surveys informed the placement of our excavation units. Assistant Site Director Taylor Thornton used a geographic information system (GIS) to align both the GPR and magnetometer data to create a basemap. A grid consisting of 1m-by-2m polygons was then placed over the basemap, with each polygon representing one potential excavation unit. Units were selected for excavation based on their relationship to both geophysical anomalies and real world topography. The coordinates for the selected units were obtained from the GIS and later shot in with a total station on site. As mentioned earlier, this site has an uncommon ditch and earthen embankment and it is this structure that we wish to investigate.
Making this field season even more exciting is the simple fact that no one has ever excavated this site before. Limited surface collections and the clean up of an erosional ditch were conducted in the 1970s, however no formal test excavation units have ever been placed at 11C120. For this reason, the CAA together with the ASU field school students are more excited than ever to share with you our experiences this summer.