LANDSCAPE HISTORY AND ARCHAEOLOGICAL SETTLEMENT PATTERNING IN THE BLACK BOTTOM OF THE LOWER OHIO RIVER VALLEY, SOUTHERN ILLINOIS

The Black Bottom is a large floodplain located north of the Ohio River within Pope and Massac Counties, Illinois. The river valley at this location preserves archaeological sites from the Paleoindian through Mississippian cultural periods. Myriad meander scrolls parallel the modern channel, recording its southward migration beginning circa 10,000 B.P. In order to study the effect of the Ohio River’s southerly migration on the archaeological record of the Black Bottom, we used an interdisciplinary approach combining remote sensing, GIS, and logistic regression. Spatial filters were applied to Landsat ETM+ and NAIP satellite imagery in order to identify and enhance relict channels; images were then imported into a GIS containing archaeological site locations as well as environmental data including elevation, slope, soil type, stream locations, and flood risk. Using these variables, logistic regression was used to develop a predictive model for the region. Preliminary results suggest that relict channels are the primary environmental determinant for prehistoric site location, with Woodland sites located significantly further from the channel than Archaic or Mississippian sites. An analysis of archaeological site distribution also provided insight into the geomorphic evolution of the Ohio River. These data suggest that the western portion of the channel was more stable through time compared to the eastern portion of the channel. A directional trend analysis further demonstrates a distinct difference in the orientation of Paleoindian versus later Woodland/Mississippian sites, with Paleoindian sites oriented northeast-southwest along the more northerly Cache River Valley, which may reflect the greater influence of the Cache River prior to 8,000 B.P. Results such as these highlight the important role interdisciplinary investigations play in understanding landscape and cultural responses to environmental change during the Late Quaternary.