Strontium concentration, radiogenic (Sr-87/Sr-86) and stable (delta Sr-88) strontium isotope systematics in a controlled feeding study

Transhumance and palaeodiet are two central themes in archaeology and using chemical analysis of bones and teeth to reconstruct trends and patterns in diet and mobility has become a cornerstone of bioarchaeology. This study has investigated strontium concentration ([Sr]), radiogenic (Sr-87/Sr-86) and stable strontium (delta Sr-88) isotope systematics in a controlled feeding experiment on domestic pigs designed to simulate terrestrial versus marine protein consumption. The results of the radiogenic (Sr-87/Sr-86) analysis offer a validation of the strontium isotope methodology. The study confirms that the radiogenic strontium isotope composition of dental enamel does represent the radiogenic strontium isotope composition of the diet. The results of the delta Sr-88 analysis have revealed a distinct shift of 0.322 +/- 0.060 % towards isotopically light Sr with trophic level. The magnitude of this shift is consistent with the predictions from the analogous shift observed in calcium isotopes. This is the first time that trophic level fractionation in delta Sr-88 has been identified in a controlled setting. Although still in its infancy, delta Sr-88 analysis has great potential to inform on trophic level systematics, to investigate dietary trends in early life and is potentially useful in examining diagenetic alteration.