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Seismic reflection profiling and basement topography in the Somali Basin: Possible fracture zones between Madagascar and Africa


  • Elizabeth T. Bunce,

  • Peter Molnar


Continuous seismic profiling in the western Somali Basin reveals basement topography aligned approximately north to south. We interpret three buried ridges, approximately 50 km apart, approximately parallel to the Davie Ridge in the Mozambique Channel, as fracture zones along which Madagascar moved away from Africa. These data therefore support the northern paleopositions of Madagascar suggested by du Toit [1937] and Smith and Hallam [1970]. The ridges seem to provide an eastern barrier to sedimentation. The basement topography forming these fracture zones has a different origin from that of Chain Ridge.