Diet and mobility among Mesolithic hunter-gatherers in Motala (Sweden) - The isotope perspective

Abstract

Recent excavations at the sites of Strandvägen and Kanaljorden in Motala, Eastern Central Sweden, have unearthed complex and varied funerary remains from the Mesolithic. The two sites are situated on opposite banks of the river Motala Ström. While geographically close and roughly covering the same time span (c. 8000–7000cal. BP), the funerary remains reveal differences and similarities in the treatment of the dead between the two localities. While at Strandvägen human bones were mostly found either scattered along the river bed or in inhumation graves, Kanaljorden contains wetland depositions of disarticulated skulls. We have conducted multi-isotope analyses of δ13C, δ15N, δ34S and 87Sr/86Sr of human and animal remains with the aim of reconstructing the dietary patterns, geographic provenance and mobility of the interred. A series of faunal reference samples and, in the case of 87Sr/86Sr, soil samples have been analysed in order to establish relevant isotopic baselines. The results show a protein intake dominated by aquatic resources, probably consisting of both freshwater and marine fish in varied proportions. The strontium isotope data indicate an interesting distinction between the individuals buried on either side of the river Motala Ström. Five out of six sampled individuals from Strandvägen have isotope ratios consistent with a local provenance, whereas ratios from seven out of eight Kanaljorden individuals indicate a non-local origin. The δ34S analysis proved problematic as a majority of the samples appear to be affected by diagenesis. This is probably the result of contamination by exogenous sulphur from surrounding fluvial and lacustrine sediments, as has previously been reported from other waterlogged sites.