Seismic reflection data from the southern Mozambique Ridge, SW Indian Ocean, show indications for a modification in the oceanic circulation system. In the absence of an age-depth model based on a drill site information gathered from the study of radiogenic isotopes of ferromanganese nodules and crusts were used. Major reorganisations in the Indian Ocean circulation system led to the onset of current controlled sedimentation in the vicinity of the Mozambique Ridge at 14 Ma. The modifications in water mass properties and path are documented in changes in reflection characteristics as well as in changes of the Nd isotope evolution in deep water masses in the Mozambique Ridge area. The general present day large scale circulation in the southern Indian Ocean is suggested to have prevailed for the last 9 my.