Sea floor spreading between Africa and the Madagascar-India-Seychelles block began during the Jurassic Magnetic Quiet Zone and was preceded by earlier rifting of Gondwanaland and deposition of Karroo sediments. Basal clastic deposition was terminated in the Early Jurassic by a regional transgression, largely a result of continental separation, followed by a general depositional regression on shelves. A major transgression occurred over most of East Africa, from late Callovian to Oxfordian, which was related to the final breakup of this area and subsequent phase of regional subsidence.

Two distinct deformational episodes, documented by erosional unconformities and siliciclastic sedimentation, occurred during the pre-Aptian and late Maastrichtian. The older event was probably the distal intraplate effect of the separation of South America and Africa; whereas the Maastrichtian tilting of northern Somalia was possibly related to a rebound effect when the Oman subduction failed at about 70 Ma.

The Cretaceous-Tertiary history of the Indian Ocean continental margins is the result of a complex depositional regression that covered the underlying Early and Middle Jurassic rifted margin. To the north, Oligocene-Miocene sediments were deposited during the opening of the Gulf of Aden and accumulated in disconnected structural depressions formed by downfaulted rotating blocks bordering the rising Somali plateau.