Journal of Archaeological Science 1983, 10, 355-360 Carbon Isotope Measurement Techniques for Bone Collagen: Notes for the Archaeologist B. S. Chisholm,” D. E. Nelson,” K. A. Hobson,” H. P. Schwarczb and M. Knyfb Stable carbon isotope analysis of archaeological human bone collagen is becoming increasingly useful in diet reconstructions. This paper describes, for archaeologists, the techniques that we have found useful in carrying out such analyses, and discusses the requirements for measurement accuracy and inter-laboratory calibration. Keywords: STABLE CARBON ISOTOPE ANALYSIS, ARCHAEOLOGICAL HUMAN BONE, PREHISTORIC DIET RECONSTRUCTION, COLLAGEN EXTRACTION. 813C MEASUREMENTS. Introduction Isotopic analysis of tissues from prehistoric people is becoming a very valuable tool for determining dietary adaptations. To date most work has been done using the stable car- bon isotopes. Studies have shown that such measurements can be used to trace the intro- duction of C, plants (principally maize) into diets otherwise based on a C, plant food chain (van der Merwe & Vogel, 1978; Bender et al., 1981; van der Merwe et al., 1981). More recently, Tauber (1981) and Chisholm et al. (1982) have shown that for coastal dwellers the same technique can be used to determine the relative consumption of marine- based protein compared to terrestrial C, plant-based protein. These measurements have been made on bone collagen, since bone is usually the only tissue preserved in archaeo- logical deposits, and the experience from 14C dating indicates that collagen preserves its isotopic composition. The long turn-over time of carbon in the bone collagen of living humans ensures that the isotopic measurement effectively represents a lifetime-average dietary intake for the individual under study (Chisholm et al., 1982). It is not yet clear how accurately these isotopic measurements determine the dietary intake of an individual. This accuracy will depend upon (1) the variation in the isotopic composition of the food sources used by an individual, (2) physiological differences that would result in differing isotopic ratios for individuals eating the same food, (3) dia- genetic effects that could result in differing isotopic ratios depending upon burial circum- stances and (4) the variability inherent in the collagen extraction and measurement tech- niques. We have research projects underway in which we are attempting to examine these aArchaeology Department, Simon Fraser University, Burnaby, British Colum- bia, Canada V5A lS6. “Geology Department, McMaster University, Hamilton, Ontario, Canada L8S 4M1. 355 0305-4403/83/040355+06 $03.00/O (0 1983 Academic Press Inc. (London) Limited