Our data highlight that the isotopic fractionation due to preferential release of light 28Si during dissolution of secondary minerals in the E horizon (Δ30SiE–BC = +2.04‰) partly accounts for the enrichment in light 28Si during re-precipitation of new clay minerals in Bhs horizon (Δ30SiBhs–BC = −0.91‰). This combined with the fact that kaolinite is progressively dissolved in the E horizon and is almost completely dissolved in the strongly weathered E horizon (CB-335 years) (Fig. 3), highlights that 28Si is redistributed in the soil profile through re-precipitation of new pedogenic clayminerals deeper in the soil profile and leaching