Glossary

Apatite (or bioapatite) Informal term for hydroxy(l)apatite, a group of phosphate minerals that comprise the mineral portion of bone.

Collagen A fibrous protein that is a principle constituent of bone, cartilage, and connective tissue.

Isotopic fractionation The difference in stable isotope ratios between food (substrate) and consumer (product) that occur during biochemical reactions.

Mass spectrometer Analytical instrument used to measure stable isotope ratios in sample materials compared to stable isotope ratio of a known standard.

Stable isotopes Chemical isotopes of an element that have an equal number of protons in their nuclei but differ in the number of neutrons present.

Arguably the most important analytical approach in archaeology since radiocarbon dating, stable isotope analysis of recovered archaeological remains provides semi-quantitative evidence for past diets and ecology. Light stable isotopes of carbon (13C,12C), nitrogen (15N,14N), and oxygen (18O,16O) are routinely used in biological and geological investigations to interpret isotopic variability in natural ecosystems. Heavy stable isotopes of strontium (87Sr/86Sr) and lead (208Pb/204Pb, 207Pb/204Pb, 206Pb/204Pb) are used to characterize place of origin and source of biological/ geological material. The application of stable isotope analysis using bone/tooth and other tissues in archaeology offers independent evidence to interpret individual and group patterns of subsistence, status, life history patterns, ecology, and provenience.

Light stable isotope studies have proved a robust method for reconstructing human palaeodiet - inference of past subsistence (‘you are what you eat’) using chemical signatures from an individual’s tissues. Such primary isotopic evidence, derived directly from human remains, complements secondary subsistence evidence (faunal and floral remains) recovered from the archaeological record. Critical to interpreting stable isotope ratios is understanding their variation and cycling in natural ecosystems, and establishing baseline data using modern plants and animals and associated archaeological remains. The dichotomy between terrestrial and marine ecosystems is particularly illustrative in delineating different subsistence regimes. Ecosystems such as freshwater systems are isotopically complex and future work must address these complexities in interpretative models using stable isotopes. New research questions focusing on palaeoclimate and provenience have expanded the scope of bone chemistry studies while advances in sampling and instrumentation have improved resolution and raised new research questions (see Paleoenviron-mental Reconstruction, Methods).