Structure of the Transkei Basin and Natal Valley, Southwest Indian Ocean, from seismic reflection and potential field data

2.5-D crustal models show that a 1.7-3.2-km-thick sediment sequence overlies a 6.3±1.2-km-thick normal oceanic crust in the deep southern Natal Valley and Transkei Basin. The oceanic crust in the study area is heterogeneous, made up of blocks of laterally varying remanent magnetization (0.5-3.5 A/m) and density (2850-2900 kg/m3). Strong modifications of accretionary processes near ridge/fracture zone intersections may be a reason of such heterogeneity.