Sr-87/Sr-86 compositional linkage between geological and biological materials: A case study from the Toyota granite region of Japan

摘要

The strontium isotope value (Sr-87/Sr-86) is often used to identify the origins of agricultural products and the movements of ancient people. Maps delineating the distribution of Sr-87/Sr-86 values can therefore be of great use. Previous Sr-87/Sr-86 distribution maps of stream sediments covering small areas of Japan largely reflect the Sr-87/Sr-86 values of underlying bedrock. It remains unclear, however, whether the Sr-87/Sr-86 values of stream sediments may also reflect the Sr-87/Sr-86 values of the nearby vegetation and fauna. We sought to resolve this question by investigating the relationship between Sr-87/Sr-86 values in biological samples and in geological samples from the sites from which the biological samples grew. The geological samples consisted of soil samples from 2 paddy fields and 13 bed sediment samples (grain size 180 mu m) from streams surrounding the paddy fields. All were collected from regions underlain by Inagawa granite bedrock, i.e., granite geology, around Toyota, Aichi Prefecture, Japan. The biological samples consisted of 4 rice plants and 1 wild boar bone, all collected in or near the same paddy fields.