REEVALUATION OF THE OCCURRENCE OF INTERSTRATIFIED CLAYS AND OTHER PHYLLOSILICATES IN SOUTHERN ALBERTA SOILS

Abstract

Clay fractions of subsoils from Southern Alberta were characterized by X-ray diffraction using improved methods of sample preparation and pretreatment control and recently reported criteria for identification of interstratified mica-smectite. Diffraction behavior of fine clays was indicative of admixtures of discrete smectite, mica and kaolinite. High angle diffraction characteristics suggested that clay fractions did not contain interstratified mica-montmorillonite. Smectite, mica, kaolinite and chlorite, in decreasing order of abundance, comprised total clay fractions. Use of the complete set of specimen pretreatments and criteria allowed identification of two smectite species and indicated that vermiculite and mixed-layer clays, previously reported to occur in these soils, are not constituents of clay separates.