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Evidence of physico–chemical and isotopic modifications in archaeological bones during controlled acid etching
Author(s) -
Balter V.,
Saliège J.–F.,
Bocherens H.,
Person A.
Publication year - 2002
Publication title -
archaeometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 67
eISSN - 1475-4754
pISSN - 0003-813X
DOI - 10.1111/1475-4754.t01-1-00065
Subject(s) - calcite , carbonate , hydroxylapatite , geology , diagenesis , dissolution , mineralogy , geochemistry , chemistry , environmental chemistry , biochemistry , organic chemistry , enzyme
It has been repeatedly shown that palaeoecological inferences from the elemental and isotopic content of carbonate hydroxylapatite of fossil teeth and bones are unrecoverable without removing diagenetic overprinting by chemical pretreatments. Such pretreatments may in turn cause modification of the biogenic signature. In this paper, we focus upon optimal removal of Ca–bearing carbonates (mainly calcite). In order to control the progress with time of calcite dissolution, we perform leaching under vacuum, and we monitor the evolution of the pH, pCO 2 , δ 13 C of released CO 2 , %C, δ 13 C and δ 18 O of the remaining mineral. For a set of different Quaternary bones and teeth, mass and isotopic balances indicate that 1 hour at most is necessary for complete dissolution of calcite with an optimal conservation of carbonate hydroxylapatite. Long–lasting experiments lead to a fractionation of hydroxylapatite 18 O/ 16 O carbonates.