Electron energy-loss spectroscopy and energy-filtered transmission electron microscopy

Iron, the fourth most abundant element in the Earth, commonly occurs in two valence states, Fe2+ and Fe3+, even within a single mineral. Determination of Fe3+/EFe ratios in minerals at sub-micrometre scale has been a long-standing objective in geosciences. One of the most important characteristics of iron is that the charge on the metal is extremely sensitive to its surrounding reduction-oxidation (redox) conditions, which often results in changes in iron valence state reflecting these conditions. The quantification of ferrous/ferric ratios in minerals can therefore provide great insights into physico-chemical conditions of rock formation such...