Diagenesis in bone and enamel apatite carbonate; the potential of density separation to assess the original composition

This paper presents a new approach to the isotopic measurement of diagenetically altered archaeological bone apatite carbonate. We describe how the existing differential dissolution method may be combined with a new approach to remove diagenetically reformed material on the basis of its greater specific gravity. We show that heavier, more diagenetically altered fraction has a higher (altered) δ13C and also increased crystallinity within one individual. In addition, we proposed one potential tool to check the validity of bone carbonate by comparing bone collagen, enamel carbonate and bone carbonate values of δ13C and radiocarbon content from the same individual. In the case of Danebury cattle, we estimated the biogenic δ13Capa value for DC83 and DC89, although it is still difficult to overcome diagenesis in order to meet the expected value, which is shown to be 1.9‰ (DC83) and 3.5‰ (DC89).

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► New approach to the diagenetically altered archaeological bone apatite carbonate.
► We combined differential dissolution method and bone density fractionation.
► Heavier, more diagenetically altered fraction shows a higher δ13C and SF.
► We proposed one potential tool to check the validity of bone carbonate.
► Bone collagen, enamel carbonate and bone carbonate values of δ13C and 14C.