A summary of strontium and oxygen isotope variation in archaeological human tooth enamel excavated from Britain (original) (raw)

Tooth enamel oxygen " isoscapes " show a high degree of human mobility in prehistoric Britain OPEN

A geostatistical model to predict human skeletal oxygen isotope values (δ 18 O p) in Britain is presented here based on a new dataset of Chalcolithic and Early Bronze Age human teeth. The spatial statistics which underpin this model allow the identification of individuals interpreted as 'non-local' to the areas where they were buried (spatial outliers). A marked variation in δ 18 O p is observed in several areas, including the Stonehenge region, the Peak District, and the Yorkshire Wolds, suggesting a high degree of human mobility. These areas, rich in funerary and ceremonial monuments, may have formed focal points for people, some of whom would have travelled long distances, ultimately being buried there. The dataset and model represent a baseline for future archaeological studies, avoiding the complex conversions from skeletal to water δ 18 O values–a process known to be problematic. Understanding and reconstructing the mobility of past populations and individuals is important in archaeological and forensic studies. One of the ways to address this topic is through the chemical analysis of skeletal remains, for the life history of an individual is recorded in the chemistry and isotopes of his or her body tissues. The use of isotope geochemistry techniques to trace mobility of individuals 1–7 relies on the fact that the chemical composition of human (and animal) tissues is acquired principally through ingested food and drink, and the isotopic composition of these items is in turn determined by local climate and environmental conditions. Isotope ratios such as 18 O/ 16 O and 87 Sr/ 86 Sr are employed in soft and hard tissues to investigate origins and mobility of past populations. The relationship between the isotopic composition of local environments and the different biological tissues varies with the type of element and isotopes investigated, the tissue, and often the type of animal species 8,9. The partitioning of isotopes in the environment is, in turn, contingent on many factors, including the geological nature of the substrate, environmental conditions, soil type, hydrological circulation, amount of precipitation, plant species and their distribution 2,8,9. Oxygen isotopes in human hard tissues are commonly used in archaeological and forensic science to study residential changes between childhood and adulthood 10–13. Here, and for the rest of the paper, oxygen isotope ratios (18 O/ 16 O) are expressed with the delta (δ) notation as δ 18 O per mil (‰), where δ = R sa /R st –1, R being the isotopic ratio, sa the sample and st the reference standard. In obligate drinkers, such as is the case for humans, oxygen isotope values (δ 18 O) in bones and teeth are related to those of local water (rain-and groundwater). Longinelli and Peretti Padalino 14 demonstrated that a direct relationship exists between the δ 18 O of drinking water and the δ 18 O of blood water in mice and humans. Following these observations, Longinelli 15 and Luz et al. 16 found that a linear correlation also exists between the δ 18 O of human skeletal bone phosphate (δ 18 O p) and the mean annual precipitation (δ 18 O w) characteristic of the area where the individual lived. This correlation is explained by the fact that the mean annual isotopic value of the precipitation falling on a certain area is similar to that of plant food and water available to individuals dwelling in the area. If the nutrients are locally sourced, their isotopic composition is reflected in that of the body water. Since biological apatite precipitates in near equilibrium with body water, it

Tooth enamel oxygen "isoscapes" show a high degree of human mobility in prehistoric Britain

Scientific reports, 2016

A geostatistical model to predict human skeletal oxygen isotope values (δ(18)Op) in Britain is presented here based on a new dataset of Chalcolithic and Early Bronze Age human teeth. The spatial statistics which underpin this model allow the identification of individuals interpreted as 'non-local' to the areas where they were buried (spatial outliers). A marked variation in δ(18)Op is observed in several areas, including the Stonehenge region, the Peak District, and the Yorkshire Wolds, suggesting a high degree of human mobility. These areas, rich in funerary and ceremonial monuments, may have formed focal points for people, some of whom would have travelled long distances, ultimately being buried there. The dataset and model represent a baseline for future archaeological studies, avoiding the complex conversions from skeletal to water δ(18)O values-a process known to be problematic.