STABLE CARBON ISOTOPES AND THE STUDY OF PREHISTORIC HUMAN DIET

Mass spectrometric analysis of the stable carbon isotope composition (C-13/C-12 or delta-C-13) of bone collagen from human remains recovered at archaeological sites provides a direct chemical method for investigating dietary patterns of prehistoric human populations. This methodology is based on the facts that (1) different food items within the human diet have distinct delta-C-13 values, and (2) the delta-C-13 value of human bone collagen is determined by the delta-C-13 value of the diet. Studies of the development of subsistence patterns based on corn agriculture, one of the most significant developments in North American prehistory, can benefit from the use of stable carbon isotope techniques because corn has a high delta-C-13 value relative to other components of the human diet. Measurements of delta-C-13 of bone collagen from prehistoric human skeletal remains from southeastern Missouri and northeastern Arkansas indicate that intensive corn agriculture began in this region around A.D. 1000, that the incorporation of corn into the human diet was a rapid phenomenon, and that 35 to 77% of the human diet from A.D. 1000 to A.D. 1600 consisted of corn. Results from an isochronous population in southeastern South Dakota (A.D. 1400) suggest that 78 to 90% of the diet of this group consisted of corn, with no difference between males and females. Coupled with more traditional archaeological methods, stable carbon isotope analysis of bone collagen can significantly enhance reconstruction of dietary patterns of prehistoric humans.