Allophanic material in Australian soils derived from Pleistocene basalt

Abstract

The clay fraction of four soils derived from Pleistocene basalt in Victoria, under a Mediterranean type climate, have been studied by X-ray diffraction, differential thermal, infrared, and electron microscopic techniques. Their chemical dissolution with alkali has shown that they contain about 25 % of allophane having a SiO2/Al2O3 molar ratio of about 4. This ratio is higher than that reported for sesquioxidic allophane and halloysitic allophane, and the name 'siliceous allophane' is proposed.