gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1998.62A.1.136 Very Early Chemical Alteration of Present-day Basalts in Mount Cameroon Bulourde M. Chauvel C. Dia A. Géosciences Rennes, CNRS, Université de Rennes 1, Campus de Beaulieu, F-35042 Rennes Cedex, France Déruelle B. LGIS, Université de Paris 6, 4 Place Jussieu, 75052 Paris Cedex 05, France Ildefonse P. LMCP, Université de Paris 6, 4 Place Jussieu, 75052 Paris Cedex 05, France Gérard M. LFS, ORSTOM, Bondy, France 1998 62A 1 257 258 Copyright © 1998, The Mineralogical Society 1998