ARSF project ET07/01: Earth crust grow at divergent plate boundaries. Led by: Dr Timothy Wright, University of Leeds. Location: Afar, Ethiopia.

The paradigm of plate tectonics is widely accepted, and there is a reasonable consensus as to how it operates. However, we have little understanding of the processes and controls involved in the break-up of continents and the generation of new oceanic crust. A recent rifting episode and eruption in the Afar region of northern Ethiopia offered a unique and timely opportunity to study the transition from continental break-up to seafloor spreading in an active setting, to document and to model the magmatic and tectonic processes within the crust and the uppermost mantle, and to determine how the crust grows at divergent plate boundaries. There was an urgent need for further geophysical, geochemical and geological observations in Afar to complement and capitalise on the recent UK geodetic and seismic monitoring of the Earth's response to this major rifting episode. We brought together a consortium with the expertise to tackle an extensive, multidisciplinary study of how plate rupture and crustal growth is achieved through the processes of lithospheric thinning and magma intrusion. We tracked the creation, migration, evolution and emplacement of magma from the asthenosphere to the crust, determine the dynamics of rifting and understand the processes that result in along-axis rift segmentation. Our work has immediate implications for hazard assessment in the region.