Doctoral Dissertation Improvement Grant: A Fresh Perspective: Isotopic Evidence for Diet in Mississippi River Valley of W-C Illinois, and Comparison with Illinois River Valley

Rutgers University New Brunswick, New Brunswick NJ

Investigators

Abstract

This study will extend a survey of prehistoric diet in the Mississippi Valley of west-central Illinois using stable isotopes of carbon and nitrogen. West-central Illinois has been the subject of much research into prehistoric biology, the result of sizeable skeletal collections and well-described archaeology. Most of this research, however, has focused on the lower Illinois River valley while the prehistory of the neighboring Mississippi River valley is much less well known. This project has already successfully produced new dietary data for the archaeological sites of Joe Gay, Lawrence Gay, Yokem, and Shild, spanning a period of over 1200 years from the Middle Woodland to Mississippian cultural eras, and provided interesting and unexpected findings. This study will further investigate these initial results, and also extend the geographical coverage of the survey to include a new site, Knight, further south in the Mississippi Valley. The innovative bone chemistry techniques used provide a new type of information to archaeologists. Previously researchers could only study the ephemeral remains of meals or tools used to produce food, and from these try to infer what prehistoric people were eating. Since food remains are poorly preserved, archaeologist's conclusions were only 'educated guesses'. Bone chemistry allows us to directly study individuals who lived in the past, and state whether they were eating native plants or the new corn introduced from tropical regions to the south, and also compare the amount of protein in people's diets. This ability to look at individuals also allows us for the first time to look at variation within communities - for example discrimination in who had access to precious meat or fish - rather than the general statements about group diet to which archaeologists were previously confined. The new data from the Mississippi Valley show that the pattern of corn introduction seems to have been similar to the Illinois Valley, but apparently with considerable variability in maize consumption when it became popular during the Late Woodland period. This variability in bone isotope values is such that they encompass a dietary corn component varying from near zero, to a very high percentage, within the same population. These intra-population differences are an enigma. Neither sex nor age explains them. This study will establish relative dates for the burials using fluoride dating, to establish if this is true contemporary variation in corn consumption within the population, or instead the result of minor temporal variation, indicating that corn was introduced very quickly. Either conclusion would be of great relevance to our knowledge of how maize was introduced and established in prehistoric populations. This study will also further investigate geographical variation, both within the Mississippi Valley itself, and between the two valleys. Initial results show that protein consumption was in the Mississippi Valley at almost every period higher than in the Illinois Valley, possibly the result of different access to protein in diverse riverside environments. The Mississippi Valley sites already analyzed are, however, close together, and this study will extend the geographical coverage of the survey to include the Knight site, further south, and closer to the Illinois Valley.