Africa is splitting apart faster than expected
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Researchers discovered that the African continent began splitting apart millions of years ago at a faster rate than previously thought.
Geologists studying the Turkana Rift Valley in Kenya and Ethiopia found the Earth’s crust there is much thinner than earlier calculations indicated, confirming the long-term process of the continent dividing. The Turkana Rift Valley extends approximately 500 kilometers and is part of the larger East African Rift System, which stretches from the Afar region of northeastern Ethiopia to Mozambique.
This system is separating the African plate from the Arabian and Somali plates. In the Turkana area, the African and Somali plates are slowly moving apart at around 4.7 millimeters per year, stretching the Earth’s crust and creating cracks. This stretching causes the land to buckle and fracture, allowing magma to rise from deep within the Earth. A research team led by Christian Rowan, a doctoral student at Columbia University’s Lamont-Doherty Earth Observatory, published their findings in Nature Communications.
They found that the rifting process in Turkana is progressing faster than expected, thinning the Earth's crust. By analyzing high-quality seismic data collected with industry partners and the Turkana Basin Institute, the researchers mapped the sedimentary structure and determined the depth of the crust under the rift. They found the crust is only about 13 kilometers thick at the center of the rift, while it’s over 35 kilometers thick in areas farther away.
Scientists estimate that the “necking” phase, when the crust becomes so thin that separation is almost inevitable, began after major volcanic eruptions around 4 million years ago. Over the next few million years, this phase will complete, leading to ocean formation as magma fills the cracks, cools, and creates new seabed, allowing water from the Indian Ocean to flow in.
The Turkana Rift Valley offers scientists a unique opportunity to study this important stage of plate evolution, as it is the first continental rift to undergo this specific rifting process.
