gems, basalt, Ethiopia

Continental rifting processes continually reshape the Earth’s surface, producing sediment-filled rift basins or rupturing the tectonic plates to form new ocean basins. Rift architecture and tectonics focus volcanic and seismic hazards, as well as geothermal energy resources, while rift systems in Africa have controlled faunal dispersal patterns and influenced human evolution in the past. The response of a plate to extension and heating provides fundamental clues into the plate rheology and the underlying mantle convection patterns. A number of models have been proposed to explain the success and failure of continental rift zones, but there remains no consensus on how strain localizes to achieve rupture of initially 125–250 km-thick plates, or the interaction between the plates and asthenospheric processes.