Bonekickers

History behind ‘The Eternal Fire’: Strontium Analysis

Strontium isotopes can be used to locate the geological region where a person spent the first twelve years or so of life. Samples are taken from the enamel on the tooth, which is laid down as the tooth grows, and contains mineral traces acquired from diet and in particular from local water.

One of these trace elements is strontium, and the ratio of two of its isotopes ⁸⁷Sr ⁸⁶Sr provide an indicator of the age of the underlying rocks through which the ground water percolates. Archaeologists can pinpoint the likely origin through knowing the geology of the region.

A related technique uses ratios of oxygen isotopes ¹⁶O and ¹⁸O which are climatically and temperature controlled. Linking the two methods allows for a more precise location. Recently this was used to suggest that the ‘Amesbury Archer’ an early Bronze Age burial found near Stonehenge, came from central Europe and not Wessex.