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Africa is going to split into two” Geologic Clues to Somali Plate –

Published on March 30, 2018 by   ·   No Comments

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At  the end of the day Africa will have to do without its horn.

The eastern part of the continent is breaking away from the rest in a geological process that will take place in thousand  of years.


The breach that arises on the eastern side of the continent is filled with ocean. This happens at a faster pace than expected and may already cause problems. The busy Kenyan Mai Mahiu Road partially collapsed after a volcanic fault line emerged.

Because of the crack parts of the road have subsided, which hinders traffic and is dangerous for motorists. According to geologist David Adede, the split is caused by volcanic activity. In an interview with  NTV , he explains: “The ‘Great Rift’ split Africa into two records. The Somali plate is slid 2.5 centimeters from the other plate. In the near future there will be a separation of the Nubian plate. ”

He says that after the road collapsed, a large hole arose that swallowed all the water, resulting in more cracks in the ground. “There is a great need for researchers who study this field so that we can determine where we can best put roads and buildings.”

The Somali plate is drifted off the Nubian plate at 45 millimeters per year. The cause is a mantle plume, which brings the heat from the core of the earth to the crust.

East Africa is one of the most geologically intriguing places on the planet—a place where the African continent is literally ripping apart. Deep rift valleys, active volcanoes, and hot springs are dramatic evidence for the powerful forces deep within the earth that are slowly reshaping the continent. Join geochemist David Hilton on an adventure to the East African Rift Valley and learn how he and his colleagues utilize geologic samples to understand this dynamic region of our planet..

Why does rifting happen?

When the lithosphere is subject to a horizontal extensional force it will stretch, becoming thinner. Eventually, it will rupture, leading to the formation of a rift valley.

Great Rift Valley, Tanzania. Shutterstock

This process is accompanied by surface manifestations along the rift valley in the form of volcanism and seismic activity. Rifts are the initial stage of a continental break-up and, if successful, can lead to the formation of a new ocean basin. An example of a place on Earth where this has happened is the South Atlantic ocean, which resulted from the break up of South America and Africa around 138m years ago – ever noticed how their coastlines match like pieces of the same puzzle?.

Maps made by Snider-Pellegrini in 1858 showing his idea of how the American and African continents may once have fitted together. https://en.wikipedia.org/wiki/Antonio_Snider-Pellegrini#/media/File:Antonio_Snider-Pellegrini_Opening_of_the_Atlantic.jpg

Continental rifting requires the existence of extensional forces great enough to break the lithosphere. The East African Rift is described as an active type of rift, in which the source of these stresses lies in the circulation of the underlying mantle. Beneath this rift, the rise of a large mantle plume is doming the lithosphere upwards, causing it to weaken as a result of the increase in temperature, undergo stretching and breaking by faulting.

Magma plume doming. DBoyd13CC BY-SA

Evidence for the existence of this hotter-than-normal mantle plume has been found in geophysical data and is often referred to as the “African Superswell”. This superplume is not only a widely-accepted source of the pull-apart forces that are resulting in the formation of the rift valley but has also been used to explain the anomalously high topography of the Southern and Eastern African Plateaus.

Breaking up isn’t easy

Rifts exhibit a very distinctive topography, characterised by a series of fault-bounded depressions surrounded by higher terrain. In the East African system, a series of aligned rift valleys separated from each other by large bounding faults can be clearly seen from space.

Topography of the Rift Valley. James Wood and Alex Guth, Michigan Technological University. Basemap: Space Shuttle radar topography image by NASA

Not all of these fractures formed at the same time, but followed a sequence starting in the Afar region in northern Ethiopia at around 30m years ago and propagating southwards towards Zimbabwe at a mean rate of between 2.5-5cm a year.

Although most of the time rifting is unnoticeable to us, the formation of new faults, fissures and cracks or renewed movement along old faults as the Nubian and Somali plates continue moving apart can result in earthquakes.

However, in East Africa most of this seismicity is spread over a wide zone across the rift valley and is of relatively small magnitude. Volcanism running alongside is a further surface manifestation of the ongoing process of continental break up and the proximity of the hot molten asthenosphere to the surface.

A timeline in action

The East African Rift is unique in that it allows us to observe different stages of rifting along its length. To the south, where the rift is young, extension rates are low and faulting occurs over a wide area. Volcanism and seismicity are limited.

Towards the Afar region, however, the entire rift valley floor is covered with volcanic rocks. This suggests that, in this area, the lithosphere has thinned almost to the point of complete break up. When this happens, a new ocean will begin forming by the solidification of magma in the space created by the broken-up plates. Eventually, over a period of tens of millions of years, seafloor spreading will progress along the entire length of the rift. The ocean will flood in and, as a result, the African continent will become smaller and there will be a large island in the Indian Ocean composed of parts of Ethiopia and Somalia, including the Horn of Africa.

Dramatic events, such as sudden motorway-splitting faults or large catastrophic earthquakes may give continental rifting a sense of urgency but, most of the time, it goes about splitting Africa without anybody even noticing.

The Credits of half oh the article goes theconversation.com

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