THE MINERALOGY AND MORPHOLOGY OF IRON AND MANGANESE OXIDES IN AN IMPERFECTLY-DRAINED SCOTTISH SOIL

The distribution, mineralogy and morphology of the iron and manganese oxides in an imperfectly-drained Scottish soil, with a diffuse Fe/Mn pan, have been examined using electron microscopy, X-ray diffraction and chemical dissolution. The Fe oxide mineralogy above and within the Fe-pan is dominated by lepidocrocite, with subsidiary amounts of ferrihydrite. In the Mn-pan itself, feroxyhyte is present and below this, goethite predominates. Vernadite is the main manganese oxide mineral within the Mn-pan. The conditions necessary for the synthesis of these minerals in the laboratory are broadly consistent with the soil conditions implied from their location within the soil profile.