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1 Department of Geology and Geophysics, University of Addis Ababa, PO Box 176, Addis Abada, Ethiopia yirgu.g{at}geol.aau.edu.et
2 Department of Geology, Royal Holloway, University of London, Egham, TW20 0EX, UK c.ebinger{at}gl.rhul.ac.uk
3 Department of Geology, University of Leicester, Leicester LE1 7RH, UK pkm{at}le.ac.uk
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.
The seismically and volcanically active East African rift system has long been a classic area for investigating rifting and break-up because its sectors encompass basins in all stages of rift to passive margin development. Its architecture is defined on the basis of both structural and magmatic components. It extends 3000 km from the Afar depression in the north to the Okavango Delta in the south, through Djibouti, Ethiopia, Kenya, Uganda, Burundi, Rwanda, Democratic Republic of Congo, Tanzania, Zambia, Malawi, Zimbabwe and Botswana. The East African rift system overlies on the most extensive seismic velocity anomalies in the Earth’s mantle, extending from the core-mantle boundary beneath the South Atlantic into the upper mantle beneath East Africa (Grand et al. 1997; van der Hilst & Karason 1999; Ritsema & van Heijst 2000). The
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This 250-word extract was created in the absence of an abstract.
