MASSIVE IRON FORMATIONS IN SOME GLEYSOLIC SOILS OF SOUTHWESTERN ONTARIO

Abstract

Massive, but very localized, iron formations have been noted in some Humic Gleysols in southern Ontario. Some of these formations weigh up to 9 kg, and invariably occur at the contact zone between sandy loam to loam surface horizons and underlying clay-rich subsoils. The contents of Fe2O3 and MnO2 of 16 samples varied from 19.6 to 49.9% and 0.8 to 11.1%, respectively, although no crystalline oxides or hydroxides of Fe or Mn could be detected by X-ray diffraction. The localized occurence of these formations suggests that Fe2+ and Mn2+ are moving laterally through the subsoil and oxidizing at some seepage point downslope in the more aerated surface horizons.