Oxygen and hydrogen isotope compositions in dentine collagen correlate strongly with oxygen isotope compositions of enamel carbonate

The isotopic composition of tooth and bone has long been exploited in ecological, environmental, and archaeological studies. Increasingly, hydrogen and oxygen isotopes in collagen are used as tracers of environment and diet. However, the isotopic relationship between hydrogen and oxygen in collagen and oxygen in tooth enamel is poorly described. A new investigation of varied wild large herbivores shows that δ18O and δ2H in collagen are both strongly correlated to δ18O in tooth enamel carbonate (r2 = 0.96 and r2 = 0.86, respectively), with a δ18O collagen vs. δ18O carbonate slope ∼ 0.8 and a δ2H collagen vs. δ18O carbonate slope ∼ 6. Given that enamel carbonate δ18O generally reflects environmental water isotopic composition, δ2H and δ18O in collagen also reflect isotopic compositions in environmental water and may be used analogously to tooth enamel for environmental or dietary studies.