Evaluating the utility of principal component analysis on EDS x-ray maps to determine bulk mineralogy

Geostandards and Geoanalytical Research
By: , and 

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Abstract

Due to advances in EDS technology, electron microscopy techniques have become an important tool to determine the relative abundance of mineral phases. However, few studies have directly compared EDS X‐ray mineralogy with traditional techniques for assessing bulk mineralogy and elemental composition. We show that analysing a limited area (~ 0.5–3.2 mm2) of fine‐grained metal extraction samples using EDS X‐ray principal component analysis phase mapping yields results that agree within 10% with more traditional techniques for mineral phases present at greater than 5% m/m. Electron beam sensitive minerals, such as the carbonates, have poor correlations between EDS and X‐ray Diffraction (XRD) and/or WD‐XRF. Likewise, poor correlations between methods can be expected for particles that are smaller than the interaction volume of the electron beam (~ 1.5 µm); this strongly affected the phyllosilicates. One strength of EDS phase mapping is that it can identify phases present below the detection limit of powder XRD (< 1%). Our results demonstrate that EDS phase mapping is sufficient to estimate bulk sample mineralogy. If polished thin sections have been prepared, this approach may save time and/or money relative to the more traditional approaches of preparing separate subsamples for XRD and/or WD‐XRF.

Publication type Article
Publication Subtype Journal Article
Title Evaluating the utility of principal component analysis on EDS x-ray maps to determine bulk mineralogy
Series title Geostandards and Geoanalytical Research
DOI 10.1111/ggr.12349
Volume 44
Issue 4
Year Published 2020
Language English
Publisher Wiley
Contributing office(s) Eastern Mineral and Environmental Resources Science Center
Description 23 p.
First page 821
Last page 843
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