Conclusions
The method was successfully applied to archaeological marine samples showing that: (1) the 87 Sr/86 Sr ratio in marine environments is not uniform, (2) 87 Sr/86 Sr differences might reflect differences in ecology and life history of different seal species, and (3) archaeological mobility studies based on 87 Sr/86 Sr ratios in humans should therefore be evaluated together with diet reconstruction.
Methods
87 Sr/86 Sr ratios were measured in tooth enamel from three seal species by laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The method enables micro-sampling of solid materials. This is the first time that the method has been applied to marine samples from archaeological collections.
Results
The analyses showed inter-tooth 87 Sr/86 Sr variation suggesting that different ratios can be detected in different regions of the Baltic Sea. Furthermore, the intra-tooth variation suggests possible different geographic origin or seasonal movement of seals within different regions in the Baltic Sea through their lifetime. Conclusions: The method was successfully applied to archaeological marine samples showing that: (1) the 87 Sr/86 Sr ratio in marine environments is not uniform, (2) 87 Sr/86 Sr differences might reflect differences in ecology and life history of different seal species, and (3) archaeological mobility studies based on 87 Sr/86 Sr ratios in humans should therefore be evaluated together with diet reconstruction.