[1] UNIV PARIS 11,HYDROL & GEOCHIM ISOTOP LAB,F-91405 ORSAY,FRANCE
[2] UNIV DAKAR,FAC SCI,CNRS,GEOL QUATERNAIRE LAB,DAKAR,SENEGAL
[3] UNIV DAKAR,INST FONDAMENTAL AFR NUIRE,GEOL LAB,DAKAR,SENEGAL
[4] ECOLE PRAT HAUTES ETUD,GEOMORPHOL LAB,F-92120 MONTROUGE,FRANCE