A giant rift, called the East African Rift, is slowly tearing apart Africa, the world’s second-largest continent .
Could Africa be completely divided in the future, and if so, when? Let’s first consider plate tectonics – the outer plates of the Earth’s surface that can collide with each other, forming mountains, or split apart, creating large basins.
Fields in the Great Rift Valley of Ethiopia, part of the East African Rift. (Photo: LucaAr)
The East African Rift is a network of valleys stretching some 3,500km from the Red Sea to Mozambique, according to the Geological Society of London (GSL). Along this giant crack, the Somali tectonic plate is being pulled eastward , separating from Africa’s larger and more ancient tectonic plate – the Nubia , according to NASA’s Earth Observatory. The Nubian Plate is also known as the African Plate.
The Somali and Nubian plates are also separating from the Arab plate to the north. These tectonic plates intersect at Afar, Ethiopia, forming a Y-shaped fault system.
The East African Rift began to form between the Arabian and the Horn of Africa about 35 million years ago, Cynthia Ebinger, chair of the geology department at Tulane University, told Live Science on June 17. This rift expanded south over time, reaching northern Kenya 25 million years ago.
The expansion zone consists of two sets of parallel fissures in the Earth’s crust. The eastern fault runs through Ethiopia and Kenya, while the western fault runs in an arc from Uganda to Malawi. The eastern branch is arid, while the western branch lies on the boundary of the Congo rainforest, according to NASA’s Earth Observatory.
Ebinger said the existence of eastern and western fault lines, as well as the detection of offshore volcanic and earthquake zones, suggest that Africa is slowly separating along some of the fault lines at a rapid rate. only about 6.35mm per year.
The East African Rift is more likely to have been formed by heat rising from the mantle – the warmer, weaker and upper part of the Earth’s mantle – between Kenya and Ethiopia. This heat causes the upper crust to swell and rise, leading to brittle continental rocks stretching and cracking.
There are many scenarios for what happens when Africa splits in two. Under one scenario, most of the Somali plate would break away from the rest of the African continent and a sea would emerge between them. The new land mass will include Somalia, Eritrea, Djibouti and eastern parts of Ethiopia, Kenya, Tanzania and Mozambique. “Another scenario is that only eastern Tanzania and Mozambique split up,” Ebinger said.
Ebinger said that if the African continent were to split, the rift in Ethiopia and Kenya could split to create the Somali Plate within the next 1 to 5 million years.
However, Africa may not be divided. According to Ebinger, the geological forces driving the rift may be too slow to separate the Somali and Nubian plates. A prominent example of a failure rift is the Central Continental Rift, which winds some 3,000km through the Upper Midwest region of North America. According to the GSL, the eastern arm of the East African Rift is a failure fault. However, the western branch is still active.