Mineralogy of fine-grained sediment by energy-dispersive spectrometry (EDS) image analysis – a methodology

. The application of energy-dispersive X-ray (EDS) spectrometry image analyses to geological, geochemical, and environmental studies is facilitated by recent increases in computer speed, storage capacity, and connectivity. EDS microbeam analyses provide digital element maps of mineral grains, with brightness directly proportional to element abundance. Using computer-based image analysis protocols, combinations of EDS element images can characterize grain mineralogy and quantify mineral abundance. This approach is well suited to the analyses of fine sand and silt-sized grains (0.425–0.010 mm), a size fraction not amenable to quantification by other mineralogical analysis methods. For this size range, 50 to more than 300 grains can be readily mapped, permitting mineral identification for concentrations >1% to be reliably distinguished.