Radiocarbon dating of calcined bones : where does the carbon come from ?

2009

Article référencé dans le Web of Science WOS:000270530800019

Zazzo A., Saliège J. F., Person A., Boucher Hugues

Radiocarbon, 2009, 51 (2), p. 601-611 ISSN 0033-8222

Over the past decade, radiocarbon dating of the carbonate contained in the mineral fraction of calcined bones has emerged as a viable alternative to dating skeletal remains in situations where collagen is no longer present. However, anomalously low, delta C-13 values have been reported for calcined bones, suggesting that the mineral fraction of bone is altered. Therefore, exchange with other sources of carbon during heating cannot be excluded. Here. we report new results front analyses on cremated bones found in archaeological sites in Africa and the Near East, as well its the results of several experiments aiming at improving our understanding of the fate of mineral and organic carbon of bone during heating. Heating of modern bone was carried out at different temperatures, for different durations, and under natural and controlled conditions, and the evolution of several parameters (weight. color, %C, %N, delta C-13 value, carbonate content, crystallinity indexes measured by XRD and FTIR) was monitored. Results from archaeological sites confirm that calcined bones are unreliable for paleoenvironmental and paleodietary reconstruction using stable isotopes. Experimental results suggest that the carbon remaining in bone after cremation likely comes front the original inorganic pool. highly fractionated due to rapid recrystallization. Therefore, its reliability for C-14 dating should be seen as close to that of tooth enamel, due to crystallographic properties of calcined bones.

Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Sociétés, développement culturel [112]

PAR00004161