Deciphering the origin of exceptional vanadium enrichment during lateritic weathering using XAS

Lateritic profiles from Suriname and Austalia may be strongly enriched in V, with V contents up to 3750 mg/kg in the most strongly weathered units. The elucidation of the evolution of V solid speciation is necessary to fully understand the processes governing exceptional enrichments in laterites , and more broadly the dynamics of V during weathering. Moreover, to predict V solubility, bioavailability, and therefore, toxicity, solid speciation determination is required, as well as redox state. The vanadium K-edge (5465 eV) is informative, and in this experiment, we propose to focus on bulk and spatially resolved XANES measurement. In that frame, we propose to accurately identify the evolution of V redox states and solid speciation in a selection of samples using X-ray absorption spectroscopy.