At the world’s edge : reconstructing diet and geographic origins in medieval Iceland using isotope and trace element analyses.

Abstract

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 analysed. Materials and Methods. Bone collagen was extracted from 50 humans (Skriðuklaustur and Skeljastaðir) and 25 animals (Skriðuklaustur) and analysed for δ13C, δ15N and δ34S. Dental enamel samples from 31 individuals (Skriðuklaustur) were also analysed for 87Sr/86Sr, δ18O, δ13C and trace elements (Pb, Sr, Zn, Ba). Results. The mean value determined from individuals from Skriðuklaustur (n = 36) was δ13C = –18.7 ± 0.8 ‰, δ15N = 12.8 ± 1.1 ‰ and δ34S = 9.0 ± 1.6 ‰, whereas at Skeljastaðir (n = 14) it was δ13C = –20.5 ± 0.8 ‰, δ15N = 7.8 ± 0.9‰ and δ34S = 9.4 ± 1.6‰. At Skriðuklaustur, human dental enamel samples (n = 31) provided a 87Sr/86Sr range of 0.7060–0.7088, δ18Ophosphate from 13.9 ‰ to 16.1 ‰ and δ13Ccarbonate from –16.6 ‰ to –12.9 ‰. Inferred drinking water (δ18Odw) 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 indicate that the people from Skriðuklaustur were born in Iceland, but some lived inland during childhood while some lived closer to the coast. Since Skriðuklaustur was a hospital, these individuals may have sought medical treatment at the monastery. The δ13C and δ15N 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.