In southern Ethiopia and northern Kenya, higher grade Neoproterozoic rocks of the Mozambique orogenic belt and lower grade Arabian-Nubian shield are juxtaposed. Because both belts formed from a collision with African cratons (Tanzania, Eastern Sahara), the region of transition is interpreted to represent the root of northward expulsion of the Arabian-Nubian shield from the Mozambique orogenic belt. In this region, the northwest-trending late Mesozoic Kenyan rift, the Cenozoic Northern Kenyan rift, and the Main Ethiopian rift form a rift complex across Pan-African structures. In the model discussed here of successive thrusts throughout Pan-Africa, expulsion was guided either by subvertical or flat-lying faults along zones of decollement and decoupling. A northwest-trending reentrant zone in the Tanzania craton (one side of an indenter) guided the penetration of the Mozambique orogenic belt. The other side was the Schliesen-Mwembeshi-Chimaliro zone in central Africa. The interpreted structure has similarities with the gravity and magnetic pattern in the Kenyan rift. This suggests that Pan-African deformation in this region controlled late Mesozoic and Cenozoic rifting.

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