Strontium (Sr) isotopes measured in fossil remains have been a useful tool to assess the geographical origin and even migrations of humans and other animals. In particular, dental enamel generally represents the ideal material, as it is dense and less prone to diagenetic replacement of Sr post-burial. However, fossil teeth can often be precious artefacts and difficult to access for destructive analysis. Here, we assess whether measuring Sr isotopes in fossil dental calculus could be used at least as a rangefinder to determine the geographical origin of an individual. We measured trace element concentrations in modern calculus (from a local dental practice), and trace element concentrations and ⁸⁷Sr/⁸⁶Sr ratios in human fossil calculus, dentine, and enamel from specimens collected in York, UK. Comparing trace element concentrations between modern and fossil calculus show that metals present in fossil calculus are mostly acquired post-burial, including Sr. The relationship between ⁸⁷Sr/⁸⁶Sr and Rb/Sr ratios in fossil calculus, dentine, and enamel suggests that the diagenetic end member would have a ⁸⁷Sr/⁸⁶Sr ratio consistent with the one modelled for the York region, but a low Rb/Sr. Without calculus data, dentine and enamel data would have probably suggested a lower ⁸⁷Sr/⁸⁶Sr ratio for a diagenetic end member, expecting high Rb/Sr values. Thus, while Sr isotopes in fossil calculus may not be useful to identify the geographical origin of an individual, they may be useful in constraining the composition of the diagenetic end member. Combining Sr isotopes in fossil dental calculus and enamel could be a more robust approach to identify geographical origin than using enamel alone.

在化石遗骸中测量的锶（Sr）同位素一直是评估人类和其他动物的地理起源甚至迁徙的有用工具。特别是，牙釉质通常是理想的材料，因为它致密且不易在埋藏后发生成岩置换。然而，牙齿化石通常是珍贵的文物，很难进行破坏性分析。在这里，我们评估测量化石牙结石中的锶同位素是否至少可以用作测距仪来确定个体的地理起源。我们测量了现代牙石中的微量元素浓度（来自当地牙科诊所），以及来自英国约克采集的标本的人类化石牙石、牙本质和牙釉质中的微量元素浓度和⁸⁷ Sr/ ⁸⁶ Sr 比率。比较现代牙石和化石牙石中的微量元素浓度表明，化石牙石中存在的金属大部分是埋藏后获得的，包括 Sr。化石牙石、牙本质和牙釉质中⁸⁷ Sr/ ⁸⁶ Sr 和 Rb/Sr 比率之间的关系表明，成岩最终成员的⁸⁷ Sr/ ⁸⁶ Sr 比率与约克地区的模型一致，但 Rb/Sr 较低。如果没有牙结石数据，牙本质和牙釉质数据可能会表明成岩端元的⁸⁷ Sr/ ⁸⁶ Sr 比率较低，预计 Rb/Sr 值较高。因此，虽然化石微积分中的锶同位素可能无法用于识别个体的地理起源，但它们可能有助于限制成岩最终成员的组成。与单独使用牙釉质相比，将化石牙石和牙釉质中的锶同位素结合起来可能是识别地理起源更可靠的方法。