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The world’s longest break up: the African tectonic plate

ByAlice Wiersma

Apr 3, 2018

Africa is splitting in two. It may take millions of years, but geologists believe that eventually, the continent will split along the Great Rift Valley. Recently, a new crack has come to light in the Suswa region of Kenya. Heavy rains are believed to be responsible for revealing the cracks by washing away volcanic ash from the nearby Mount Longonot, and seismic activity is considered the root cause of the fissures. These fissures are no small matter, with some of them being up to 20 meters wide and around 50 feet deep. They have disrupted infrastructure and transport, with roads and highways falling into the crevasses.

The Great Rift Valley runs along a geological fault line and was formed by the interaction between the Arabian and African tectonic plates.

Tectonic plates are in continuous movement and as such create new continents and oceans over a very long time span. Depending on the specific interaction between the plates, different geological processes occur. Transform boundaries can cause earthquakes as the plates slide against one another, while converging plates lead to mountain and volcano formation and diverging boundaries lead to mid-ocean ridges and the formation of the Great Rift Valley. These are all continuous natural occurrences and take place at roughly the same rate as your fingernails grow. The African plate is considered by geologists to be in the process of splitting into the Somalian and the Nubian plates.

So what’s allowing for this divergent tectonic plate movement in the Great Rift Valley region? Research from Brain Bagley and Andrew Nyblade in 2013 strongly favoured the idea of superplumes. Superplumes are upwellings of mantle from the mantle-core boundary that push upwards and exert a large force on the tectonic plates from below. This force is pushing and pulling the African plate apart and will one day lead to the formation of a new continent between the rest of Africa and Madagascar.

Madagascar itself was once part of the African continent. It split from Africa as part of the Indian landmass 135 million years ago. Around 88 million years ago, the Indo-Madagascar plate then split further into their modern day equivalents. The length of time Madagascar has been isolated from the mainland means that its flora and fauna has evolved into a variety of species unique to the island.

One can expect that following the split of the African plate, similar speciation will occur. This will take some time. The split is not expected to occur for another 50 million years and evolution by natural selection needs time to work its magic following geographic isolation.

Needless to say, the southeast region of Africa will eventually look nothing like what it does today, which isn’t that surprising considering Scotland used to be an equatorial rainforest.

Image credit: Rodrigo Jay via pixabay

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