La sidéritite de Pagala (Togo) ; son évolution en chapeau de fer

At Pagala (Togo), was found in a profile a massive sideritite orerlain by a thick ferruginous cap representing the gossan. The investigations done allow us to conclude that this gossan is the direct weathering product of the sideritite. This transformation is carried out with inheritance of microtextures, massive and selective leaching of elements and good conservation of micas. Textural and geochemical similarities of many gossans of the area with the one of Cascade favour a carbonaceous origin for these gossans