Editing Isotope analysis (section)

==Tissues affected==

[[Isotopes of oxygen|Isotopic oxygen]] is [[incorporated (disambiguation)|incorporated]] into the body primarily through [[ingestion]] at which point it is used in the formation of, for archaeological purposes, [[bone]]s and [[teeth]]. The oxygen is incorporated into the [[hydroxylcarbonic]] [[apatite]] of bone and [[tooth enamel]].

[[Bone]] is continually [[wikt: remodelled|remodelled]] throughout the lifetime of an individual. Although the rate of [[turnover rate|turnover]] of isotopic oxygen in [[hydroxylapatite|hydroxyapatite]] is not fully known, it is assumed to be similar to that of [[collagen]]; approximately 10 years. Consequently, should an individual remain in a region for 10 years or longer, the isotopic [[oxygen ratio]]s in the bone hydroxyapatite would reflect the isotopic oxygen ratios present in that region.

[[Teeth]] are not subject to continual remodelling and so their isotopic oxygen ratios remain constant from the time of formation. The isotopic oxygen ratios, then, of teeth represent the ratios of the region in which the individual was born and raised. Where [[deciduous teeth]] are present, it is also possible to determine the age at which a child was [[weaned]]. [[Breast milk]] production draws upon the [[body water]] of the mother, which has higher levels of [[oxygen-18|<sup>18</sup>O]] due to the preferential loss of [[oxygen-16|<sup>16</sup>O]] through sweat, urine, and expired water vapour.

While teeth are more resistant to chemical and physical changes over time, both are subject to post-depositional [[diagenesis]]. As such, isotopic analysis makes use of the more resistant [[phosphate]] groups, rather than the less abundant [[hydroxyl]] group or the more likely diagenetic [[carbonate]] groups present.