Halloysite from a Strongly Weathered Soil at Mont Jacques Cartier, Quebec

Halloysite was the only mineral present in the clays of samples obtained at the 1.5- and 3.9-m depths from a strongly weathered soil at Mont Jacques Cartier in the Gaspé region of Québec. With an increase in particle-size, kaolinite replaced halloysite and was the only one of the two minerals detected in the coarse silt and the sand fractions. The halloysite was identified and differentiated from the kaolinite in this soil by x-ray diffraction using formamide solvation which expands halloysite but not kaolinite within a few minutes. Infrared spectra of the soil halloysite and Georgia kaolinite were the same except for small differences in the hydroxyl region which showed a characteristic hand at 3550 cm−1 for halloysite. Electron micrographs showed the soil halloysite to be tubular with some exceptionally long (10 µm) tubes. The analyses, especially by the energy-dispersive x-ray method, indicated that the halloysite and kaolinite in this soil have weathered from blotite and feldspars that are present in the parent rock and the coarse silt and sand fractions. This weathering probably occurred mostly in pre-Wisconsinan time as this soil appears to have escaped disruption by glaciation.