A knot in a network: Residential mobility at the Late Iron Age proto-urban centre of Basel-Gasfabrik (Switzerland) revealed by isotope analyses

Laser ablation strontium isotope analysis of human remains from Harlaa and Sofi, eastern Ethiopia, and the implications for Islamisation and mobility

“…Yet the situation with strontium is less clear and questions remain about the residence time and turnover of strontium in the body, the proportion of strontium contributed to a growing foetus from dietary vs maternal body tissue sources, and how these things may vary across different species (Lugli et al 2017;Lugli et al 2019;Montgomery 2010). Many previous studies have measured and successfully interpreted strontium isotope data from deciduous human teeth (reviewed in Hrnčíř and Laffoon 2019;Knipper et al 2018;Knudson et al 2016;Lugli et al 2017;Lugli et al 2019) and earlier-forming permanent dentition that likely overlaps with the breastfeeding and weaning period (Evans, Chenery, and Fitzpatrick 2006; reviewed in Hrnčíř and Laffoon 2019;Müller et al 2003). More broadly, earlier-forming teeth such as 1st molars are routinely used for research into the mobility of past populations using other isotope systems such as δ 18 O (Prowse et al 2007) despite similar concerns about fractionation effects caused by breastfeeding (Wright and Schwarcz 1998).…”

Coalescing traditions—Coalescing people: Community formation in Pannonia after the decline of the Roman Empire

“…The short time span between the incorporation of the strontium and the premature death of the individuals, increase the probability of the trace element for being of local origin. Several larger, previously published series of Sr isotope data confirm significantly less variable 87 Sr/ 86 Sr ratios among the teeth of children than among those of adult individuals [32,49,[52][53][54]. Alt et al [49] and Knipper et al [52] discussed their value as representatives of the strontium that originated from a dietary catchment of a few kilometres radius of a given site extensively.…”

“…Several larger, previously published series of Sr isotope data confirm significantly less variable 87 Sr/ 86 Sr ratios among the teeth of children than among those of adult individuals [32,49,[52][53][54]. Alt et al [49] and Knipper et al [52] discussed their value as representatives of the strontium that originated from a dietary catchment of a few kilometres radius of a given site extensively. Because strontium isotopes do not fractionate remarkably during metabolic processes, systematic differences between deciduous teeth, that start forming in utero, and permanent teeth, that start forming postpartum, are neither expected nor found in empirical comparisons [52].…”

“…Alt et al [49] and Knipper et al [52] discussed their value as representatives of the strontium that originated from a dietary catchment of a few kilometres radius of a given site extensively. Because strontium isotopes do not fractionate remarkably during metabolic processes, systematic differences between deciduous teeth, that start forming in utero, and permanent teeth, that start forming postpartum, are neither expected nor found in empirical comparisons [52]. Nevertheless, infants' teeth may occasionally reflect non-local isotope ratios, either due to enamel formation in utero of a non-local woman who moved during pregnancy, or due to movement of a child with its family or for other reasons for child mobility.…”

Tracing mobility patterns through the 6th-5th millennia BC in the Carpathian Basin with strontium and oxygen stable isotope analyses

“…Individuals with an isotope composition matching the site-specific baseline range in the early-forming tooth but having a later mineralising tooth with a strontium isotope ratio falling outside the range were considered "mobile". Furthermore, the normal variation in strontium isotope composition within a site could be calculated by adding two standard deviations to the average value of the difference between both deciduous teeth, between the deciduous tooth and the PLOS ONE first molar, and between both first molars [58]. Therefore, when the difference between the 87 Sr/ 86 Sr ratios or δ 18 O value of one individual's teeth exceeded the offset expected for the normal variation within a site, the individual could be considered "mobile" as well (see Figs 5 and 7).…”