Alération météorique des feldspaths en milieu méditerranéen humide

Plagioclases and K-Feldspars are extracted from a saprolite developed on granite under the Mediterranean humid climate. Polarizing microscope, SEM, mineralogical analyses were used. In sandy saprolite, plagioclases are the first to alter in amorphous material from which kaolinite crystallises. Argillans impregnate the very porous weathered plagioclases which habitus is preserved. In sandy clayed saprolite, K-feldspars are weathered later : simultaneously, corrosion and amorphous material occur. Progressively they become smaller and even disappear. In comparison with other climatic areas, and considering other granite minerals alterations, we can think that weathering, in its ultime state, under this climate, approximates this of humid tropical area, without going further than kaolinite crystallisation.Penven M.J., Fedoroff N., Michel Robert. Alération météorique des feldspaths en milieu méditerranéen humide. In: Pétrologie des altérations et des sols. Vol. II : Pétrologie des séquences naturelles. Colloque international du CNRS, Paris 4-7 juillet 1983. Strasbourg : Institut de Géologie – Université Louis-Pasteur, 1983. pp. 149-160. (Sciences Géologiques. Mémoire, 72