MINERAL TRANSFORMATIONS IN SOME SANDY SOILS FROM ALBERTA, CANADA

Three sandy Luvisols from Alberta were studied through mineral investi gations and geochemical prediction based on the ionic composition of t he in situ soil solution to evaluate the stability and formation of mi nerals. The transformation of phyllosilicates in this study appears to be dominated by the vermiculitization of mica and to a lesser extent of chlorite. Hydroxy interlayered phyllosilicate is also observed thro ughout the sola. There are good agreements between geochemical predict ions and mineral determination for calcite, dolomite, goethite, hemati te and lepidocrocite. These observation suggest that a geochemical mod el using data from the composition of in situ soil solution can be use d to evaluate the stability and formation of the low quantities of the common carbonates, oxides and oxyhydroxides. The unique micro- or pal eo-environments are believed to be responsible for the disagreement be tween the model and the mineral observation for gypsum while the ''ant i-gibbsite'' effect of organic components may be responsible for the n on-formation of gibbsite.