Tooth isotopes offer window into South Australia's early colonial history

The archaeologists studied the origin of people in a free ground section of the cemetery to help construct a clear picture of colonial migration before 1880.

Lead Author and Flinders University Masters student, Christine Adams, says tooth enamel and dentine samples from the graves show one person was likely born in Adelaide, eight were originally from Britain and Ireland, and three could have been from either location.

"Only one person was likely born elsewhere according to our results. A total of 52 samples were tested, four samples per individual -- 26 for strontium, 26 for oxygen, and for both enamel and dentine. Strontium isotope samples were successfully analysed from the enamel and dentine of all individuals.

The finding that all individuals in this study may have, based on at least one isotope and dental material and supported by dietary data from the time, come from either Adelaide or the United Kingdom correlates well with the overwhelmingly British origin of colonists in South Australia and the cemetery's own records before 1880."

Flinders University co-author Associate Professor Ian Moffat says the study proves how isotope methods can be used to test the origin of case studies around Australia.

"This research technique is important for provenance studies where individuals could have migrated or moved substantial distances," he says. "This study also shows that strontium isotope methods can be used to test a specific hypothesis rather than just being used to confirm a general location."

Co-author and leader of the St Mary's research project, Flinders University's Professor Donald Pate, says the analysis combined a range of isotope investigations with further analysis of diets from previous studies.

"As the life history of these individuals is not well-documented in historical records, isotopic data provides important information about migration and mobility in a colonial South Australian population," says Professor Pate.

"Our records and data suggest the majority of individuals interred within the free ground section of St Mary's were either born in Britain or South Australia, but some may have migrated from other locations. Burial samples total 70 individuals at the cemetery, but degraded and missing tooth elements mean not all were suitable for investigation."

Professor Pate is a veteran of studies at the site. At the request of the church, research began at St Mary's Cemetery 20 years ago, with archaeologists painstakingly recovering remains from the free ground section ever since.