At The World'S Edge: Reconstructing Diet And Geographic Origins In Medieval Iceland Using Isotope And Trace Element Analyses

Objectives A multi-isotope study was conducted on individuals buried at Skriouklaustur monastery (AD 1493-1554) to investigate their geographic origins and dietary composition. Comparative material from individuals excavated from Skeljastaoir, an inland farm site was also analyzed.Materials and methods Bone collagen was extracted from 50 humans (Skriouklaustur and Skeljastaoir) and 25 animals (Skriouklaustur) and analyzed for delta C-13, delta N-15, and delta S-34. Dental enamel samples from 31 individuals (Skriouklaustur) were also analyzed for Sr-87/Sr-86, delta O-18, delta C-13, and trace elements (Pb, Sr, Zn, Ba).Results The mean value determined from individuals from Skriouklaustur (n = 36) was delta C-13 = -18.7 +/- 0.8 parts per thousand, delta N-15 = 12.8 +/- 1.1 parts per thousand, and delta S-34 = 9.0 +/- 1.6 parts per thousand, whereas at Skeljastaoir (n = 14), it was delta C-13 = -20.5 +/- 0.8 parts per thousand, delta N-15 = 7.8 +/- 0.9 parts per thousand, and delta S-34 = 9.4 +/- 1.6 parts per thousand. At Skriouklaustur, human dental enamel samples (n = 31) provided a Sr-87/Sr-86 range of 0.7060-0.7088, delta O-18(phosphate) from 13.9 to 16.1 parts per thousand and delta C-13(carbonate) from -16.6 to -12.9 parts per thousand. Inferred drinking water (delta O-18(dw)) values range from -12.3 to -8.9 parts per thousand. Sr concentrations range from 25.8 to 156.7 ppm, Ba from 0.11 to 0.81 ppm, Zn from 43.8 to 145.8 ppm, and Pb from 0.13 to 9.40 ppm.Discussion A combination of results indicates that the people from Skriouklaustur were born in Iceland, but some lived inland during childhood while others lived closer to the coast. Since Skriouklaustur was a hospital, these individuals may have sought medical treatment at the monastery. The delta C-13 and delta N-15 values determined from bone collagen indicate that the people residing at Skriouklaustur consumed a diet high in marine protein, while those residing at Skeljastaoir exhibit values more consistent with terrestrial resources.