Weathering processes and dating of soil profiles from São Paulo State, Brazil, by U-isotopes disequilibria.

This study reports the use of the U-series radionuclides U and U for dating two soil profiles. The soil horizons developed over sandstones from Tatuí and Pirambóia formations at the Paraná sedimentary basin, São Paulo State, Brazil. Chemical data in conjunction with the U/U activity ratios (AR's) of the soil horizons allowed investigating the U-isotopes mobility in the shallow oxidizing environment.