1. Imerys; 2 place Édouard Bouillières 31100 Toulouse France
2. Geosciences Environment Toulouse (GET), UMR 5563, UPS-CNRS-IRD-CNES, ERT 1074 Géomatériaux, 14; Avenue Êdouard Belin 31400 Toulouse France
3. CNRS, Univ. Bordeaux; ICMCB, UPR 9048; 33600 Pessac France