Determination of carbonate vein chemistry using portable X-ray fluorescence and its application to mineral exploration

The composition of carbonate minerals infilling hydrothermal veins can vary as a function of factors including fluid chemistry, temperature and pressure. If effectively quantified, carbonate vein chemistry can represent an important tool in mineral exploration. We present a method for determining carbonate vein chemistry using portable X-ray fluorescence analysis (pXRF) utilising matrix matched certified reference materials (CRMs) to assess pXRF analyser performance, before establishing strict QA/QC procedures, along with linear calibration equations for Mg, S, Mn, Fe, Zn, Sr and Pb. However, low concentrations of mineralization-related elements in commercially available CRMs meant raw S, Zn and Pb concentrations determined for case study samples could not be reliably corrected. Our new workflow was then applied to carbonate vein samples collected from Mount Isa, Northwest Queensland, Australia. Though complexity of this system limited the interpretation of results, the case study showed that pXRF can also be used to identify veins with multiple generations of carbonate infill. Portable X-ray fluorescence analyses, used in conjunction with robust QA/QC processes is a powerful tool that can quickly and cost-effectively inform decisions during exploration programs.