An investigation of Re and Os contamination by materials used in rock and mineral powdering

抄録

Elemental and isotopic analyses of geological samples require several sample-preparation steps that can introduce contamination and result in analytical inaccuracies. In this study, the influence of different materials used as rock and mineral powdering equipment (agate, stainless steel and tungsten carbide) on Re-Os contents and Os isotope ratios was evaluated by crushing quartz sand with variable pre-powdering grain sizes (2–4, 6–10, and 8–16 mesh). Rhenium-Os contents were least affected by crushing in agate, and increased by up to one and two orders of magnitude after crushing in stainless steel and tungsten carbide, respectively. Osmium contamination is affected by the duration of powdering, whereas this is not the case for Re. ¹⁸⁷Os/¹⁸⁸Os ratios decrease due to contamination. Agate powdering equipment is optimal for sample preparation for Re-Os concentration and isotopic analysis. Moreover, a small pre-powdering grain size (8–16 mesh) can reduce contamination.