Reconstructions of ancient mobility based on strontium isotopes are only ever as reliable as estimates for baseline values of bioavailable strontium in the study area. Current biosphere mapping for Britain suggests that there are no sizeable areas hosting ⁸⁷Sr/⁸⁶Sr values above 0.714 south of Cumbria. As a result, archaeological humans or animals with such (for Britain) ‘highly radiogenic’ strontium isotope values are commonly interpreted as having moved either from Scotland or abroad. This paper presents the first dedicated strontium isotope map for South-West England based on 98 modern biosphere samples (including 68 new measurements). Numerous samples from the Cornubian granite (Dartmoor) have ⁸⁷Sr/⁸⁶Sr values above 0.714 (maximum 0.7287) and, based on their distribution, it is suggested that the previously elusive ‘highly radiogenic’ values are characteristic for areas where the soil has with high rubidium concentrations. These occur at lower elevations which are better suited for agriculture and permanent human settlement than the high moors. Previous interpretations of archaeological samples from southern Britain may need to be revised considering these new results, but they also highlight the continued need for biosphere sampling and the usefulness of geochemical maps as a routine part of strontium isotope investigations in archaeology.

基于锶同位素的古代流动性重建仅与研究区域生物可利用锶基线值的估计值一样可靠。目前英国的生物圈测绘表明，在坎布里亚郡以南没有超过 0.714 的⁸⁷ Sr/ ^{86 Sr 值的大面积区域。}因此，具有这种（对于英国）“高度放射性”锶同位素值的考古人类或动物通常被解释为从苏格兰或国外迁移。本文介绍了基于 98 个现代生物圈样本（包括 68 个新测量值）的英格兰西南部首张专用锶同位素图。来自 Cornubian 花岗岩 (Dartmoor) 的大量样品含有⁸⁷ Sr/ ⁸⁶Sr 值高于 0.714（最大值 0.7287），并且根据它们的分布，表明以前难以捉摸的“高放射性”值是土壤铷浓度高的地区的特征。这些发生在比高沼地更适合农业和人类永久定居的低海拔地区。考虑到这些新结果，以前对英国南部考古样本的解释可能需要修改，但它们也强调了对生物圈取样的持续需求以及地球化学图作为考古学中锶同位素调查的常规部分的有用性。