A giant crack, called the East African Rift, is slowly splitting Africa, the world's second largest continent.
Fields in Ethiopia's Great Rift Valley, part of the East African Rift Zone Photo: LuCaAr
Could Africa break up completely in the future, and if so, when? First, consider tectonic plates—the outer layers of the Earth's surface that can collide with each other, forming mountains, or pull apart, creating vast basins.
The East African Rift is a network of valleys that stretches about 3,500 kilometers 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 older Nubia tectonic plate, according to NASA’s Earth Observatory. The Nubia plate is also known as the African plate.
The Somali and Nubian plates are also breaking away from the Arabian plate to the north. These tectonic plates meet at Afar, Ethiopia, forming a Y-shaped rift system.
The East African Rift began forming between Arabia 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. The rift expanded southward over time, reaching northern Kenya about 25 million years ago.
The rift consists of two parallel sets of faults in the Earth's crust. The eastern rift runs through Ethiopia and Kenya, while the western rift runs in an arc from Uganda to Malawi. The eastern branch is arid, while the western branch lies on the border of the Congo rainforest, according to NASA's Earth Observatory.
The existence of eastern and western fault lines and the discovery of offshore earthquake and volcanic zones suggest that Africa is slowly splitting apart along some fault lines at a rate of just about 6.35 millimeters per year, Ebinger said.
The East African Rift likely formed as heat rose from the asthenosphere—the hotter, weaker upper part of the Earth’s mantle—between Kenya and Ethiopia. This heat caused the upper crust to bulge and rise, causing brittle continental rock to crack.
There are several scenarios for what would happen if Africa splits. In one scenario, most of the Somali tectonic plate would separate from the rest of the African continent, creating a sea between them. The new land mass would include Somalia, Eritrea, Djibouti, and the eastern parts of Ethiopia, Kenya, Tanzania, and Mozambique. “Another scenario is that only eastern Tanzania and Mozambique would separate,” Ebinger said.
Ebinger said that if the African continent were to split, the fault line in Ethiopia and Kenya could separate to create the Somali plate within the next 1-5 million years.
Africa, however, may not split in two. 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 failed rift is the Midcontinental Rift, which snakes for about 3,000 kilometers (1,800 miles) across the Upper Midwest of North America. According to GSL, the eastern branch of the East African Rift is a failed rift. However, the western branch is still active.
Thu Thao (According to Live Science )
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