Scandium biogeochemistry at the ultramafic Lucknow deposit, Queensland, Australia

Tropical ultramafic regoliths (derived from iron‑magnesium‑nickel-rich mantle rocks) can yield significant nickel and cobalt ore reserves and are mined across the Asia-Pacific Region. In some instances, ultramafic laterite deposits are also enriched in scandium. However, the behaviour of scandium in soil-plant systems, and any potential geobotanical relationships with economic resources of scandium, have rarely been examined. In this study, we applied biogeochemical prospecting techniques to a known scandium deposit in Central Queensland, Australia. > 80 species originating from 24 families were sampled, all species were typical of semi-arid climate on Ferralsols. Intensive washing with hexane proved to be effective for removing soil contamination. The foliar scandium concentrations were strongly correlated to foliar chromium and aluminium concentrations (likely due to contamination), and two plant specimens had foliar Sc >1 μg g⁻¹ (maximum of 1.46 μg g⁻¹). The usefulness of plant foliar analyses for Sc in biogeochemical prospecting remains unknown.