High-precision in situ 87Sr/86Sr analyses through micro-sampling on solid samples: applications to Earth and Life Sciences

An analytical protocol for high-precision, in situ micro-scale isotopic investigations is presented here, which combines the use of a high-performing mechanical micro-sampling device and high precision TIMS measurements on micro-Sr samples, allowing for excellent results both in accuracy and precision. The present paper is a detailed methodological description of the whole analytical procedure from sampling to elemental purification and Sr-isotope measurements. The method offers the potential to attain isotope data at the micro-scale on a wide range of solid materials with the use of minimally invasive sampling. In addition we present three significant case studies for geo and life sciences, as examples of the various applications of micro-scale 87Sr/86Sr isotope ratios, concerning i) the pre-eruptive mechanisms triggering recent eruptions at Nisyros volcano (Greece), ii) the dynamics involved with the initial magma ascent during Eyjafjallajökull Volcano’s (Iceland) 2010 eruption, which are usually related to the precursory signals of the eruption, iii) the environmental context of a MIS 3 cave bear, Ursus spelaeus. The studied cases show the robustness of the methods, which can be also be applied in other areas, such as cultural heritage, archaeology, petrology, and forensic sciences.