Differential diagenesis of strontium in archaeological human dental tissues

The investigation of prehistoric human migration from the measurement of Sr -isotope ratios within preserved tissue is critically dependent on the pres ervation of biogenic Sr. A number of recent studies have involved isotope r atio measurements on samples of archaeological tooth and bone, but doubt re mains as to the extent of diagenesis in various skeletal tissues and the ef fectiveness of procedures designed to decontaminate them. The authors have compared Sr abundance and isotope ratios in enamel and dentine from archaeo logical teeth in order to assess the integrity of the biogenic Sr signal pr eserved within the respective tissues. It is concluded that enamel appears, in most cases, to be a reliable reservoir of biogenic Sr, but that dentine , and by implication bone, is not. The diagenesis of dentine is highly vari able even between burials within a single site. For the majority of teeth, dentine diagenesis was not simply by addition of soil-derived Sr, but invol ved substantial, sometimes complete, turnover of the original biogenic mate rial. It is suggested that, for most of the samples investigated, current d econtamination techniques may not have been effective in isolating biogenic Sr from dentine. Similar considerations are likely to apply to archaeologi cal and fossil bone, but the possibility arises to use dentine and enamel m easurements to assess the effectiveness of decontamination procedures which may then be used for bone. (C) 2000 Elsevier Science Ltd. All rights reser ved.