The added value of calcined pars petrosa ossis temporalis and teeth to the study of past mobility

To date, several cremation deposits from archaeological contexts in modern day Belgium have been investigated using a multidisciplinary approach, whereby mobility was examined via strontium isotope analysis of calcined rib, diaphysis and cranial bone fragments. The strontium isotope ratios measured on these different skeletal elements showed a wide variation which, with reference to plant samples from the area, are suggestive of mobility and/or changes in landscape use during the last decade or so of the cremated individuals’ lives. With few exceptions, these previous studies did not include the sampling of the pars petrosa (PP) and teeth, although these elements can provide information about childhood residence. The aim of this present study was to explore the potential of sampling early-forming skeletal tissues for strontium isotopes, and to compare the results to previously studied material.
Strontium isotope analyses were performed on the fully calcined PP and teeth from Herstal and Court-Saint-Étienne, two Late Bronze Age – Early Iron Age cremation sites in the region of Belgium. The inner cortex of the otic capsule (PP) was sampled. This part contains isotope ratios reflective of the strontium ingested during infancy and early childhood (up to 2 years of age). Furthermore, the teeth were determined whenever possible, since each tooth type represents a different age span. The differences observed between childhood (PP and dentition) strontium isotope ratios and those of continuously remodeling skeletal tissues (cranium, diaphysis, rib) were highly indicative of changes in diet or in the place of residence during the life of these individuals, allowing us to deepen our understanding of the sites in the context of the period.
This pilot study on cremation deposits from LBA – EIA Belgium demonstrates that including these skeletal tissues reflecting early childhood strontium intake is essential when trying to understand mobility of individuals and populations in the past.