Shaw, Ben, 2009. Prehistoric migration in Melanesia: Evidence from isotope, trace element and non-metric dental trait analyses.
Migration is a widely used explanation for culture change in the archaeological record. In the Southwest Pacific Islands, migration was essential for the colonisation of the island groups in Near and Remote Oceania during the Lapita Cultural Complex (~3,300 – 2,200 BP). Lapita is an archaeologically recognised cultural group defined by the presence of a distinctively decorated ceramic tradition.
This thesis seeks to directly assess prehistoric migration and mobility in New Guinea and the Bismark Archipelago using isotope (87Sr/86SR and δ18O), trace element (Ba/Sr) and non-metric dental trait analysis. Samples included in the analyses were from Lapita human (Reber-Rakival and Lifafaesing) and pig (Reber-Rakival) samples in the Bismarck Archipelago as well as from a post-Lapita human population on the New Guinea mainland (Nebira). Isotopes and trace elements were measured in the tooth enamel of individuals because enamel develops during childhood and provides a retrospective record of where the individual lived while the tooth was developing. Therefore a shift in location during adulthood can be inferred. On the other hand, non-metric dental traits are known to be genetically controlled and inherited. Assessing these traits in prehistoric populations may therefore allow individuals to be identified that have migrated from genetically distinct populations.
The isotope and trace element data from the human individuals from Reber-Rakival suggests that one young female may have been a migrant to the site. Also, several pigs were possibly transported to the island from four potentially separate locations. No migrant individuals were identified at Lifafaesing. The isotope and trace element data from the Nebira individuals suggest there may have been nine migrants to the site from four potentially separate locations. A group of five non-local individuals at Nebira potentially migrated from a coastal location.
The non-metric dental traits were only recorded in the individuals from Reber-Rakival and Nebira as those teeth were from intentional inhumations. The non-metric dental traits exhibited a similar patter of trait frequency within both populations. While some patterns of these traits showed differences between the local and non-local groups identified through isotope analysis, there were no statistically significant differences in trait frequencies between the groups.
The variation in the isotope and trace element data measured in the tooth enamel of the individuals within and between the sampled sites indicates there is enough variability to identify prehistoric migration and mobility in a Pacific Island context, with a clear distinction between island and inland populations identified. The similarity in non-metric dental trait frequencies in the individuals from Reber-Rakival and Nebira may reflect interaction and migration between genetically similar communities, but was not as powerful for identifying migration as the isotopic data.