Chemical and Mineralogical Mapping of Platinum-Group Element Ore Samples Using Laser-Induced Breakdown Spectroscopy and Micro-X-Ray Fluorescence

Standard techniques for geochemical and mineralogical characterisation are time-consuming, they can involve significant sample preparation and they are prone to error. The aim of this work is to show how the emerging fast laser-induced breakdown spectroscopy (LIBS) technique can be valuable for mineral exploration. For this purpose, the well-established micro-X-ray fluorescence (mu-XRF) technique was used to validate the LIBS data. Two ore samples from the platinum-group elements (PGE) Lac des Iles mine (Ontario, Canada) were analysed both by LIBS and mu-XRF. The fast mineralogical and elemental mapping provided by LIBS allowed the identification of four major silicate phases (chlorite, bytownite, actinolite, hornblende) and four minor sulfide phases (Pd-bearing pentlandite, chalcopyrite, pyrrhotite, pyrite). Multi-element chemical mapping and mineral characterisation using mu-XRF corroborated the LIBS analyses for the composition, distribution and abundance of minerals in PGE ore samples. These findings demonstrate the ability of the LIBS technique to perform direct fast high-resolution mapping of the chemical and mineralogical composition of PGE ore samples. This work highlights the advantages of LIBS for this application of being much faster and more sensitive to trace elements (e.g., Pd), as well as to low atomic number elements.

Automated summary

The emerging fast laser-induced breakdown spectroscopy (LIBS) technique shows great potential for mineral exploration, providing direct, fast, and high-resolution mapping of chemical and mineral composition. LIBS has the advantages of faster speed and greater sensitivity to trace elements (e.g., Pd) and low atomic number elements.