Automated mineralogy based on energy dispersive X-ray fluorescence microscopy (µ-EDXRF) applied to plutonic rock thin sections in comparison to Mineral Liberation Analyser
Abstract. Recent development in the application of energy dispersive X-ray fluorescence spectrometry mapping (µ-EDXRF) has opened new opportunities for fast geoscientific analyses. Acquiring spatially resolved spectral and chemical information non-destructively for large samples of up to 20 cm length provides valuable information for geoscientific interpretation. Using supervised classification of the spectral information, mineral distribution maps can be obtained. In this work, thin sections of plutonic rocks are analyzed by µ-EDXRF and classified using the supervised classification algorithm Spectral Angle Mapper (SAM). Based on the mineral distribution maps, it is possible to obtain quantitative mineral information, i.e. to calculate the modal mineralogy, search and locate minerals of interest and perform image analysis. The results are compared to automated mineralogy obtained from the Mineral Liberation Analyser (MLA) of a Scanning Electron Microscope (SEM) and show good accordance, revealing variation resulting mostly from the limit of spatial resolution of the µ-EDXRF instrument. Taking into account the little time needed for sample preparation and measurement, this method seems well suitable for fast sample overviews with valuable chemical, mineralogical and textural information, and additionally, enabling the researcher to make better and more targeted decisions for subsequent analyses.