Determination of Re, Os, Ir, Ru, Pt, Pd Mass Fractions and 187Os/188Os Ratios of Organic-Rich Geological Reference Materials

At present, reported data for Re-PGE mass fractions (in particular) and Os-187/Os-188 isotope ratios of organic-rich reference materials (RMs) are rare, hampering the comparison of data quality between different laboratories. In this study, we measured the Re-PGE (Os, Ir, Ru, Pt and Pd) mass fractions, as well as Os-187/Os-188 isotope ratios of five shale RMs, including USGS SGR-1b (oil shale), SBC-1 (marine shale), SCo-2 (silty marine shale), ShTX-1 (calcareous organic-rich shale) and ShCX-1 (calcareous shale), and one oil RM, NIST RM 8505. The results show that the five shale RMs have similar upper continental crust-normalised PGE-Re patterns and are generally homogeneous in Re-PGE mass fractions and Os-187/Os-188 isotope ratios at test portions of 0.2-0.5 g, and thus can be used as matrix-matched RMs for Re-Os and PGE of shale samples. The oil RM NIST 8505 and its asphaltene separates are also roughly homogeneous in Re-PGE mass fractions and Os-187/Os-188 isotope ratios at test portions of 0.1-0.3 g and can potentially be used as an oil RM for Re-Os and PGE.

Automated summary

This study measured the Re-PGE mass fractions and Os-187/Os-188 isotope ratios of shale and oil reference materials, and found that they can be used as matrix-matched reference materials for Re-Os and PGE analysis of shale and oil samples.