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 Skriðuklaustur monastery (AD 1493–1554) to investigate their geographic origins and dietary composition. Comparative material from individuals excavated from Skeljastaðir, an inland farm site was also analyzed. MATERIALS AND METHODS: Bone collagen was extracted from 50 humans (Skriðuklaustur and Skeljastaðir) and 25 animals (Skriðuklaustur) and analyzed for δ(13)C, δ(15)N, and δ(34)S. Dental enamel samples from 31 individuals (Skriðuklaustur) were also analyzed for (87)Sr/(86)Sr, δ(18)O, δ(13)C, and trace elements (Pb, Sr, Zn, Ba). RESULTS: The mean value determined from individuals from Skriðuklaustur (n = 36) was δ(13)C = −18.7 ± 0.8‰, δ(15)N = 12.8 ± 1.1‰, and δ(34)S = 9.0 ± 1.6‰, whereas at Skeljastaðir (n = 14), it was δ(13)C = −20.5 ± 0.8‰, δ(15)N = 7.8 ± 0.9‰, and δ(34)S = 9.4 ± 1.6‰. At Skriðuklaustur, human dental enamel samples (n = 31) provided a (87)Sr/(86)Sr range of 0.7060–0.7088, δ(18)O(phosphate) from 13.9 to 16.1‰ and δ(13)C(carbonate) from −16.6 to −12.9‰. Inferred drinking water (δ(18)O(dw)) values range from −12.3 to −8.9‰. 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 Skriðuklaustur were born in Iceland, but some lived inland during childhood while others lived closer to the coast. Since Skriðuklaustur was a hospital, these individuals may have sought medical treatment at the monastery. The δ(13)C and δ(15)N values determined from bone collagen indicate that the people residing at Skriðuklaustur consumed a diet high in marine protein, while those residing at Skeljastaðir exhibit values more consistent with terrestrial resources.