Awards Earth processes infographic

★ Wong, Kevin // The East African Rift: a geological guide


This infographic highlights some of the key geological features in my research area, the northernmost East African Rift, which is the largest active continental rift zone in the world. It has been designed with a general audience in mind, who may not be familiar with the concept of continental rifting or the presence of volcanoes in Ethiopia but have a sufficient background or interest in geology or geography.


What is continental rifting?

Continental rifting is the process by which a continent is tectonically pulled apart to form a new ocean basin. This extension is achieved by breaking, weakening and thinning Earth’s thick continental crust by creating fractures (called faults) and intruding molten rock (called magma).

The 6,000-km-long East African Rift system is the largest active continental rift system on Earth. Here the Somalian Plate of East Africa is separating from Central Africa at 10-50 mm/yr. Continental rifting evolves into seafloor spreading from the south of the Rift to the north; the northernmost parts of the East African Rift showcase these final stages of the continent-to-ocean transition.

What are the main features of the East African Rift?

The Western Rift is the arm of the East African Rift that runs from south to central Africa. There are fewer volcanoes along this rift arm as it is mostly non-magmatic.

The other arm is the Kenyan Rift (or Eastern Rift). Thick African crust is broken apart at the sides of the rift by large faults. Melting of Earth’s mantle deep under the rift creates magma, which uses these faults as passageways through the crust to the surface, erupting to form volcanoes.

The Kenyan Rift transitions into the later-stage Ethiopian Rift at Turkana to its north, a low-lying region cut by many faults. Most faults in the Ethiopian Rift occur in its centre; the large faults and volcanoes present on the rift flanks in Kenya are now inactive. Mantle melting is also now closer to the Earth’s surface. The crust remains thick, but subject to constant intrusions of hot magma.

Further to the north lies Afar. Here the crust is very thermally weakened by magma, making extension much easier. The crust is now thinned significantly and mostly made of volcanic rock instead of continental basement material. Within a few million years the mantle melting region beneath the Rift will become very shallow, and a new mid-ocean spreading ridge will be formed along with a new ocean basin. The northernmost point of the East African Rift connects with the Red Sea Rift and Aden Ridge at the Afar triple junction. These two other rift systems push the Arabian plate away from Africa.

Why are you studying this area?

The chemistry of volcanic rocks and minerals from the Ethiopian Rift can tell us more about how magma is generated and transported to the surface, helping us to understand how the Rift develops. This is of interest to geologists studying the processes behind the final stages of continental breakup, and to the large subpopulation of Ethiopia who live in the cities present within the seismically and volcanically active Rift.

Kevin Wong

Kevin’s research interests lie in volcanology and igneous petrology, with focus on erupted materials at volcanic settings. Understanding the physical and chemical properties of volcanic rocks and minerals allows Kevin to paint a picture of magma generation and transport in the Earth’s mantle and crust underlying volcanoes, with emphasis of those in the Ethiopian Rift for his PhD.

Kevin’s University of Leeds profile


Twitter: @GeoKevW

Organisation: Earth and Environment, University of Leeds