The results of the two- and three-dimensional magnetic inversions performed on data indicate the crustal magnetization has decayed exponentially for the last 10 Ma, and that this decay has been fairly symmetric about the ridge axis. After removal of the mean temporal decay, the residual field is characterized by more positive magnetizations at the second-order discontinuities, regardless of initial magnetization direction. A model that involves the preferential emplacement of serpentinized lithologies near the discontinuities is proposed to explain this correlation. Several ridge-parallel depressions located on the flanks of the ridge axis are also regions of more positive magnetizations.