THE MINERALOGICAL AND GEOCHEMICAL CHARACTERISTICS OF THE TERTIARY PALYGORSKITE FROM IDA OU GAILAL (NE OF TAROUDANNT) AND TOUNDOUT (NE OF OUARZAZATE) - GENETIC-IMPLICATIONS

The palygorskites, focused on in this study appear in sediments of the Erguita Basin and the Southern marginal zone of the High Atlas. They have been accumulated in a lacustrine environment during the Tertiary. Mineralogical analysis of the materials indicates that they contain i llite, interstratified illite-smectite, palygorskite, Al-smectite, Mg- smectite, kaolinite and chlorite. A geochemical study based on the rar e earth element and transition trace element contents suggests that pa lygorskites have formed by a structural transformation mechanism of al uminosilicate precursor that might be illite and/or Al-smectite.