Strontium isotope analysis on human skeletal remains from the Hobi and Ikawazu shell-mounds in Aichi Prefecture, Japan

Abstract

Many human skeletal remains of the Late–Final Jomon period have been found in shell-mounds on the Atsumi peninsula in Aichi Prefecture, Japan. Several types of burials have been found, such as mass burial and bone-gathering burials arranged like a square board (banjo-shuseki burial). In this study, strontium isotope analysis was performed to reveal the meanings of banjo-shuseki burials. The materials included 22 samples of tooth enamel and bones from the Hobi shell-mound, and 30 samples from the Ikawazu shell-mound. The concentration of calcium and strontium was measured, as were the strontium isotope ratios. The results indicated that the tooth enamel from the banjo-shuseki burial exhibited higher strontium isotope ratios than those of tooth enamel from the single burial in Hobi. The tooth enamel from the banjo-shuseki burial and a mass burial in Ikawazu included some individuals with higher strontium isotope ratios. These ratios were higher than the range of the values of human bone samples, modern plants around the sites, and the enamel of terrestrial animals, indicating the possibility that these people grew up in a different place to the sites where they were buried. The individuals in the banjo-shuseki burials may include immigrants who grew up in other areas or their diets incorporated food from other areas.