East African Rift Crust Thins to 13 Kilometres as Plates Pull Apart at 4.7 mm a Year
Updated
Updated · BBC Discover Wildlife · Jun 14
East African Rift Crust Thins to 13 Kilometres as Plates Pull Apart at 4.7 mm a Year
3 articles · Updated · BBC Discover Wildlife · Jun 14
Summary
High-resolution seismic data show the Turkana Rift’s crust has thinned to just 13 kilometres in places, far below the more than 35 kilometres measured outside the rift zone.
Researchers said that extreme thinning reflects faster-than-expected rifting between the African and Somali plates, which are separating at about 4.7 millimetres a year.
The team linked the change to crustal “necking,” where stretching weakens the crust, opens pathways for magma and raises the odds that the continent will eventually split and form new oceanic crust.
That transition is still distant: the Turkana Rift began forming about 45 million years ago, and scientists estimate it will take several million more years before a new ocean starts to develop.
The findings may also explain why the Turkana Basin preserves more than 1,200 hominin fossils, with volcanic activity and subsiding land creating sediment-rich basins that protected ancient remains.
As Africa splits to form a new ocean, which landlocked nations could become the world's next maritime powers?
Did Africa's tectonic rift create a cradle for humanity, or was it simply the perfect trap for preserving our ancestors' fossils?
Breaking Africa Apart: 2025 Discoveries in the East African Rift and the Birth of a New Ocean
Overview
Recent research in the Turkana Rift, part of the East African Rift System, has revealed that earlier episodes of rifting significantly thinned and weakened the Earth's crust. This thinning, known as 'necking,' is similar to how saltwater taffy stretches and becomes thinner in the middle when pulled. As a result, the crust along the rift’s axis is now only about 13 kilometers thick, much less than surrounding areas. This weakened state has set the stage for the intense geological activity seen today, suggesting the region has reached a critical threshold where the crust is more likely to break apart, driving the continent’s ongoing split.