The oxygen-isotope composition of bones and teeth is derived ultimately from the isotopic content of the local water consumed by a region’s inhabitants.
Isotopic ratios in the water in turn depend on a variety of geographic and climatic factors, including temperature, humidity, and latitude. Different regions are thus likely to have distinguishable isotopic “signatures,” which are then expressed in the bones and teeth of the people living in them.
Furthermore, the isotopic composition of each tooth is fixed when that tooth develops and remains unchanged subsequently because dental tissue does not remodel. However, bone constantly remodels through an individual’s lifetime, so the isotopic composition of the bone will be continually equilibrating to the individual’s most recent environment.
It is thus possible to detect movement over the course of an individual’s lifetime and to identify the region(s) where that individual spent his or her early years and also the region where he or she passed the final years of life.
Spence, M. W., White, C. D., Longstaffe, F. J., and Law, K.R. "VICTIMS OF THE VICTIMS: Human trophies worn by sacrificed soldiers from the Feathered Serpent Pyramid, Teotihuacan." Ancient Mesoamerica, 15 (2004), 1-15.
Yeah, this is a text wall, but I thought it was cool. ouo