Strontium isotopes in human teeth and bones as a monitor of mobility
Direct evidence of human residential mobility has been difficult to obtain in prehistory. Archaeologists have generally used artifact styles as a proxy for people to investigate population movement. We approach this problem by comparing strontium isotope ratios in human bones and in teeth . Dental enamel forms during early childhood and retains Sr isotopes from the local geology at that time, while bone, which is chemically remodeled, assimilates Sr isotopes reflecting residence during the last years of one's life. Thus differences in strontium isotope ratios between bone and tooth enamel reveal movement during the life of the individual. Strontium isotope ratios in teeth that do not match those of the local geology should indicate immigrants to a site...
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OK, I see the connection now. I didn't realize that Strontium was used to monitor mobility.