Marine mollusc shells hold significant potential for deciphering past environmental conditions and seasonality of hominin subsistence strategies. While stable oxygen isotope ratio values of shells are currently the gold standard, they have significant drawbacks, such as complex and time-consuming sampling procedures and assumptions on the oxygen isotope composition of seawater in the past. The analysis of shell elemental ratios offers an alternative with minimal sample preparation and no assumptions on water composition. Although elemental ratios have already shown a correlation with seawater temperatures, this relationship is also influenced by other environmental factors and endogenous physiological mechanisms, resulting in noisy ratio profiles that are dependent on the exact measurement path across the growth lines of the shell. This study introduces “virtual sampling” (VS), a novel technique enhancing the analysis of the Mg/Ca ratios of marine mollusc shells measured by Laser-Induced Breakdown Spectroscopy (LIBS). It is based on the automatic detection of the isochronous -growth- lines and its employment for averaging the elemental ratios. This approach mitigates the noise inherent to linear scanning trajectories and improves the estimation accuracy of the elemental ratios. Our investigation focuses on analysing twenty-four modern and six archaeological Patella vulgata Linnaeus, 1758 shells and the effects derived from the application of this virtual sampling versus the traditional techniques. This advancement in elemental analysis provides a more robust basis for seasonal mollusc collection estimations than the linear LIBS scanning and analysis approach, contributing to a better understanding of human lifeways in archaeological studies.

中文翻译：

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虚拟采样：海洋软体动物贝壳中 Mg/Ca 比值元素映射新技术的考古意义


海洋软体动物壳在破译过去的环境条件和古人类生存策略的季节性方面具有重要潜力。虽然贝壳的稳定氧同位素比值目前是金标准，但它们也存在明显的缺点，例如复杂且耗时的采样程序以及过去对海水氧同位素组成的假设。壳元素比分析提供了一种替代方案，只需最少的样品制备，并且不对水成分进行假设。尽管元素比率已经显示出与海水温度的相关性，但这种关系也受到其他环境因素和内源性生理机制的影响，导致嘈杂的比率分布取决于穿过壳生长线的精确测量路径。本研究引入了“虚拟采样”（VS），这是一种新技术，可增强通过激光诱导击穿光谱 （LIBS） 测量的海洋软体动物壳的 Mg/Ca 比率的分析。它基于对等时生长线的自动检测及其用于平均元素比率。这种方法减轻了线性扫描轨迹固有的噪声，并提高了元素比的估计精度。我们的调查重点是分析 24 个现代和 6 个考古 Patella vulgata Linnaeus，1758 年贝壳，以及应用这种虚拟采样与传统技术相比所产生的影响。与线性 LIBS 扫描和分析方法相比，元素分析的这一进步为季节性软体动物收藏估计提供了更可靠的基础，有助于在考古研究中更好地了解人类的生活方式。