The Victims at Sandby Borg - Tracing Mobility and Diet Using Strontium Analyses
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The Victims at Sandby Borg - Tracing mobility and diet using strontium analyses Author: Kerstin Calleberg Master thesis at the Archaeological Research Laboratory, Stockholm University 2019 Supervisors: Kerstin Lidén & Gunilla Eriksson Abstract Sandby borg, an Iron Age ringfort on Öland, Sweden has been and is still at the center of attention in media and archaeological research. The massacre uncovered at the site during recent years opens many doors for analyses on the Migration Period (c. 400-550 AD) Iron Age skeletal remains. Eighteen teeth (molars) from 12 individuals and three rodent teeth were chosen for strontium (87Sr/86Sr) analyses. This was done to establish whether these individuals were locals or non-locals to Öland. The analyses displayed a, for the most part, local 87Sr/86Sr ratio. Two non-locals were identified, as well as a pattern of higher 87Sr/86Sr peaks on numerous of the individuals during a certain age span, which could indicate a local weaning process with a special food. Keywords: 87Sr/86Sr, strontium, migration, Sandby borg, Öland, massacre, teeth, Migration Period, Iron Age, Laser Ablation. Acknowledgment Big thanks to my supervisors Kerstin Lidén and Gunilla Eriksson for interesting discussions and for sharing your knowledge on the subject. I would also like to thank Tammy Jamerson for reviewing the English in this thesis. Many thanks should also be given to my classmates for their wonderful dark humor, for backing each other, and for the nice hangs. Finally, all my love to my spouse Jimmy for your amazing support and patience. Also, thanks to my cat Iris for the lovely cuddles. Cover illustration: Photographs by Kalmar county Museum and Kerstin Calleberg. Illustration and cover assembly by Kerstin Calleberg Table of contents 1. Introduction ...................................................................................................................................1 1.1. Preface .....................................................................................................................................1 1.2. Aims and research questions ....................................................................................................1 2. Background ....................................................................................................................................2 2.1. General background .................................................................................................................2 2.2. The ringforts on Öland..............................................................................................................3 2.3. Sandby Borg .............................................................................................................................5 2.4. Strontium isotope analysis .......................................................................................................7 2.5. Other Sandby borg analyses .....................................................................................................7 2.6. Öland geology ..........................................................................................................................8 3. Material..........................................................................................................................................9 3.1. Teeth...................................................................................................................................... 16 4. Ethical aspects .............................................................................................................................. 16 5. Methods ....................................................................................................................................... 17 5.1. LA-MC-ICP-MS ........................................................................................................................ 17 5.2. Enamel formation age ............................................................................................................ 17 5.3. Theory and definitions............................................................................................................ 19 7. Results .......................................................................................................................................... 20 8. Discussion..................................................................................................................................... 27 9. Conclusions .................................................................................................................................. 33 10. Further research ......................................................................................................................... 33 11. Summary .................................................................................................................................... 34 12. References .................................................................................................................................. 35 13. Appendix .................................................................................................................................... 38 13.1. Pictures material and Laser Ablation..................................................................................... 38 13.2. Rodents 87Sr/86Sr & overall plot of all the individuals analyzed from Sandby borg ................. 43 13.3. Raw sample data .................................................................................................................. 45 13.4. LA-MC-ICP-MS instrument settings & standards ................................................................... 58 13.5. Observations LA-MC-ICP-MS................................................................................................. 59 13.6. Material table ....................................................................................................................... 60 1. Introduction 1.1. Preface During the European Migration Period (c. 400-550 AD) there was economic, political, and social instability among people and societies. The turbulence affected the Scandinavian realms and people’s movement across the land. The Swedes (Swedish: svear) and the Geats (Swedish: götar) discordance during this time is depicted in Beowulf and Old Norse sagas (Stjerna 1905). The dissonance and instability might be why numerous people were brutally slaughtered and left at the place of death inside ringfort Sandby borg on Öland in Sweden. This has been interpreted as a massacre. Usually, people of the Migration Period buried the dead at cemeteries. Artifacts found inside the ringfort tell us that the people had long distance contacts to the Roman Empire and other parts of Europe during that time. This is therefore a very significant place and leaves many questions for researchers to answer. Many of the individuals show trauma to their head and body and no clear defensive wounds are present on the skeletons. DNA- and osteological analysis show that the majority of the adult individuals were men. Children of different ages and an infant tell us that there must have been women present on this site at the time of the massacre (Gunnarsson et al. 2015; Alfsdotter 2018). Of interest, to understand what happened on the site, is to identify if these people were locals (born and living on Öland) or non-locals (not born or living on Öland). To do this, teeth of some individuals were analyzed. Teeth grow in a special pattern and by analyzing the teeth’s strontium (87Sr/86Sr) values that grow during different times of the individual’s lifetime, a pattern of migration or diet could be detected. 1.2. Aims and research questions The aim of this thesis is to establish whether these people were locals or non-locals to Öland by using strontium analysis on teeth with laser ablation. - Are the individuals locals or non-locals? - Can movement or dietary changes over time of the individuals be established? - Is it possible to trace seasonal food intake? - What can this tell us about the function of the ringfort? - What can the analyses tell us about the events on the site? 1 2. Background 2.1. General background The European Migration Period (c. 400-550 AD) started as a result of the weakened Roman Empire. What is seen as the springboard (375 AD) of the Migration Period was when a Mongolian nomadic people, the Huns, started to raid throughout Europe. During a hundred years they raided and plundered large parts of Central Europe. This was the starting point of the movement of people in Europe. The defeat of the eastern Goths was the start of the western expansion. At almost the same time the western Goths defeated the Romans and entered the Balkans in 378 AD and Italy the year 401. In 395 AD the Roman emperor Theodosius I divided the empire into two parts, the Western Roman Empire and the Eastern Roman Empire (Byzantium). The Goths occupied Rome in 410, which forced the Romans to leave Britannia. Around 400 AD the Franks and many other tribes entered the now open Gaul. These ravages have been described as barbaric and lively. Attila, who became the leader of the Huns in 446 AD, was defeated in 453, which led the Huns out of Europe. The Germanic people had in 492 taken the leading role of Rome and at the same time the kingdom of Francia was created (Kinder & Hilgemann 1981:113-117). Scandinavia was to a very high degree affected and involved in the warlike happenings on the continent. Evidence of this are