Oxygen isotopes in bioarchaeology: Principles and applications, challenges and opportunities

Oxygen isotope analyses of skeletal remains (18O/16O, δ18O) are a powerful tool for exploring major themes in bioarchaeology (the study of biological archaeological remains) and can aid in the reconstruction of past human-environment interactions, socio-cultural decisions and individual life histories. Making use of the preserved animal and human tooth and bone commonly found at archaeological sites, applications include the reconstruction of palaeoclimate and palaeoseasonality; animal husbandry and management practices; human and animal lifetime mobility and provenance; and cultural practices such as breastfeeding, weaning and even past culinary preparation techniques. With a range of other uses across the natural, physical, chemical and biological sciences, oxygen isotope analyses are also highly cross-disciplinary, with developments in the field of isotope bioarchaeology potentially feeding into other fields and vice-versa. The purpose of this paper is to provide a summary of the biogeochemical background of oxygen isotope systematics from the water cycle to human and animal skeletal tissues for archaeologists and other scientists, and to explore how these have been utilised in terrestrial bioarchaeological research. In this way, we aim to provide an overview resource for stable isotope analysts in archaeology and the wider earth science community, as well as for archaeological practitioners and consumers interested in specific applications. By providing a summary of fundamental isotope mechanics alongside a review of recent developments in the field, we hope to highlight the potential of oxygen isotope bioarchaeology to not only reveal environmental and ecological aspects of the past relevant to human groups using archaeological materials, but also to illuminate past human decisions and behaviours. Current limitations and caveats of the approaches used are also explored.