Ams ¹4c dating of human bones using sequential pyrolysis and combustion of collagen

The Radiocarbon Dating Laboratory at the University of Illinois has been using the pyrolysis-combustion technique to separate pyrolysis-volatile (Py-V) or low molecular weight and pyrolysis-residue (Py-R) or high molecular weight compounds for 14C dating of organic remains since 2003. We have applied this method to human collagen dating to examine the 14C age difference between low and high molecular weight organic compounds. Results show that both fractions of late prehistoric period human bones from Illinois archaeological sites yield identical 14C dates but that Py-V or low molec-ular weight fractions of Archaic period human bones appear to be slightly contaminated. In this case, Py-V components or low molecular weight collagen fraction yield older 14C dates, which could result from contamination from old organic-rich sedi-ments. The pyrolysis-combustion technique provides an economical alternative method to date bones that have not been sat-isfactorily dated using conventional purification techniques.