Is Africa splitting into two continents?

Jul 26, 2023
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To all those who don't believe in evolution or plate tectonic movement its happening in real time...Isn't science great
 
Africa is splitting in two – here is why

Published: March 29, 2018

A large crack, stretching several kilometres, made a sudden appearance recently in south-western Kenya. The tear, which continues to grow, caused part of the Nairobi-Narok highway to collapse. Initially, the appearance of the crack was linked to tectonic activity along the East African Rift. But although geologists now think that this feature is most likely an erosional gully, questions remain as to why it has formed in the location that it did and whether its appearance is at all connected to the ongoing East African Rift. For example, the crack could be the result of the erosion of soft soils infilling an old rift-related fault.

The Earth is an ever-changing planet, even though in some respects change might be almost unnoticeable to us. Plate tectonics is a good example of this. But every now and again something dramatic happens and leads to renewed questions about the African continent splitting in two.

The Earth’s lithosphere (formed by the crust and the upper part of the mantle) is broken up into a number of tectonic plates. These plates are not static, but move relative to each other at varying speeds, “gliding” over a viscous asthenosphere. Exactly what mechanism or mechanisms are behind their movement is still debated, but are likely to include convection currents within the asthenosphere and the forces generated at the boundaries between plates.

These forces do not simply move the plates around, they can also cause plates to rupture, forming a rift and potentially leading to the creation of new plate boundaries. The East African Rift system is an example of where this is currently happening.

The East African Rift Valley stretches over 3,000km from the Gulf of Aden in the north towards Zimbabwe in the south, splitting the African plate into two unequal parts: the Somali and Nubian plates. Activity along the eastern branch of the rift valley, running along Ethiopia, Kenya and Tanzania, became evident when the large crack suddenly appeared in south-western Kenya.
A large crack, stretching several kilometres, made a sudden appearance recently in south-western Kenya. The tear, which continues to grow, caused part of the Nairobi-Narok highway to collapse. Initially, the appearance of the crack was linked to tectonic activity along the East African Rift. But although geologists now think that this feature is most likely an erosional gully, questions remain as to why it has formed in the location that it did and whether its appearance is at all connected to the ongoing East African Rift. For example, the crack could be the result of the erosion of soft soils infilling an old rift-related fault.

The Earth is an ever-changing planet, even though in some respects change might be almost unnoticeable to us. Plate tectonics is a good example of this. But every now and again something dramatic happens and leads to renewed questions about the African continent splitting in two.

The Earth’s lithosphere (formed by the crust and the upper part of the mantle) is broken up into a number of tectonic plates. These plates are not static, but move relative to each other at varying speeds, “gliding” over a viscous asthenosphere. Exactly what mechanism or mechanisms are behind their movement is still debated, but are likely to include convection currents within the asthenosphere and the forces generated at the boundaries between plates.

These forces do not simply move the plates around, they can also cause plates to rupture, forming a rift and potentially leading to the creation of new plate boundaries. The East African Rift system is an example of where this is currently happening.

The East African Rift Valley stretches over 3,000km from the Gulf of Aden in the north towards Zimbabwe in the south, splitting the African plate into two unequal parts: the Somali and Nubian plates. Activity along the eastern branch of the rift valley, running along Ethiopia, Kenya and Tanzania, became evident when the large crack suddenly appeared in south-western Kenya.

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.

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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?

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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/Anton...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.

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Mantle plume (left). Reprinted from Tetrophysics, Vol 513, Oliver Mearle, 'A simple continental rift classification' Copyright (2011), with permission from Elsevier.

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.

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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 can give continental rifting a sense of urgency. However, rifting is a very slow process that, most of the time, goes about splitting Africa without anybody even noticing.

This article was updated and the headline changed on April 7 to reflect ongoing discussion by geologists about the cause of the large crack that appeared on the East Africa Rift and whether its location is related to the African continent split.
See: https://theconversation.com/africa-is-splitting-in-two-here-is-why-94056

Quartz Africa Weekly Brief

Scientists say a new ocean will form in Africa as the continent continues to split into two

By Uwagbale Edward-Ekpu

PublishedAugust 13, 2020

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Afar depression, 120 meters below sea level, an arid region near the Eritrean border in Ethiopia Image: REUTERS/Michel Laplace Toulouse/Files

The East African Rift system made up the western and eastern continental rifts, and stretches from the Afar region of Ethiopia down to Mozambique. It is an active continental rift that began millions of years ago, splitting at 7mm annually. The regular eruption of volcanoes along the rift and new insights into the break up of continents adds to the belief that the continent may be splitting to form a new ocean.

East Africa is home to several visible geographical wonders that have attracted tourists to the area. These include Lake Malawi and Tanzania’s Lake Tanganyika—respectively, the fourth largest freshwater and the second deepest lakes in the world. It also includes active volcanoes such as the Ol Doinyo Lengai in Tanzania, and the DallaFilla and Erta Ale in Ethiopia.

The Erta Ale stands out as one of the world’s most active volcanoes and one of the only eight and possibly the longest-existing lava lakes in the world.

Though not visible to tourists, among the wonders of the region is the Victoria microplate, one of the largest continental microplates. The Victoria microplate is a rift branch which, along chains of deep lakes and volcanoes, makes up the several features of the East African Rift System.

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In eastern Africa, in the Afar region of Ethiopia, a nearly barren rockscape marks the location of the meeting place of three separate pieces of the Earth’s crust. Image NASA

In a recent study, the Victoria microplate, which lies between the eastern and western branches of the Rift, was found to be rotating counterclockwise for the last two years with respect to the African Plate—the major tectonic plate constituting most of the African continent. This microplate was found to rotate in the opposite direction to all the other neighboring microplates in the region.

While this gives researchers new insight into the splitting process of the East Africa Rift system, the “Y” shaped end of the rift at the Afar region is getting more attention, as to where an ocean will likely be formed if the splits continue. The “Y” shaped junction is where the African, Somalian, and Arabian tectonic plates meet near Djibouti and Eritrea and it is associated with active volcanos including the Erta Ale volcano.

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Colored digital elevation model showing tectonic plate boundaries, outlines of the elevation highs demonstrating the thermal bulges and large lakes of East Africa. Image by NASA

Researchers believe the volcanic activity in the region suggests a rift-to-ridge transition. The Erta Ale has been erupting constantly for over 50 years and it is believed that as the Erta Ale continues to erupt, a new narrow ocean basin with its mid-ocean ridge will be formed.

However, researchers are uncertain about the future of the East African rift—whether the split will continue and an ocean will eventually be formed. At the rate at which the Afar rift is splitting, it will take tens of million years for an ocean to eventually be formed.

See: https://qz.com/africa/1891403/africa-is-splitting-into-two-to-create-a-new-ocean


The Great Rift Valley, where Africa is slowly pushed and pulled apart by uprising material in earth's mantle. Eventually, the rift will become deep enough to host a new ocean, separating Eastern Africa from the rest of the continent. The Great Rift was discovered almost hundred years ago by an intrepid geologist. John “Jack” Walter Gregory was born in London in 1864. His interest in the natural world and adventures emerged in his early years of study. During his later scientific career he would visit Europe, Africa, Australia, India, North- and South America, even the remote islands of Spitsbergen in the Arctic. His interest in geology came from the necessity to know where he was:
… my attention was first directed to geology in order to understand the geography of the districts through which I rambled, and the, often, apparently erratic course of the rivers … and to understand local topography.
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