ABSTRACT
Northeast Africa underwent repeated phases of regional extension in the late Phanerozoic. This produced failed rifts that preserve a wide spectrum of structural development. One system, the Neogene Red Sea rift, has partially attained active sea floor spreading. The large NE Africa data base is used to develop a general model of continental rift evolution. Low-angle normal faults and complex, asymmetric basins dominate early rift geometries. Reorganization of border faults and isostatic uplift lead to abandonment of some sub-basins and, in general, more laterally continuous late-stage basins. In some rift systems, such as the Red Sea, the final phase of continental extension is marked by a shift to high-angle, non-rotational normal faulting. This may represent a fundamental difference between Basin and Range style deformation, where repeated generations of detachments develop, and sites of successful oceanic rifting.
