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'Pulsing, like a heartbeat': Rhythmic mantle plume rising beneath Ethiopia is creating a new ocean
When you buy through links on our articles, Future and its syndication partners may earn a commission. Rhythmic pulses of molten rock are rising beneath eastern Africa, according to a new study. The pulsing plume of hot mantle beneath Ethiopia, driven by plate tectonics, is slowly pulling the region apart and forming a new ocean near the Gulf of Aden and the Red Sea, researchers reported June 25 in the journal Nature Geoscience. "We have found that the evolution of deep mantle upwellings is intimately tied to the motion of the plates above," Derek Keir, an Earth scientist at the University of Southampton and the University of Florence, said in a statement. "This has profound implications for how we interpret surface volcanism, earthquake activity, and the process of continental breakup." The mantle plume lies under Ethiopia's Afar region, at the intersection of three tectonic plates. All of the rifts between these plates are different ages, and they are changing at different rates; some are in the process of forming new oceans, while others are pulling apart the crust beneath Africa. But the structure and motion of the plume, as well as the forces driving these movements, aren't well understood. To investigate the structure of the crust and the mantle plume beneath it, the scientists studied the chemical compositions of more than 130 samples of volcanic rocks from the Afar region. These samples provided information about the depth and composition of melted rock beneath the surface. The team also used computer models to determine how the region might respond to different kinds of mantle plumes and compared those responses to existing geological data. A single mantle plume lies beneath all three rifts, the researchers found, but its chemical composition is not uniform. Further, the molten rock surges upward rhythmically, leaving behind distinct chemical signatures. "The chemical striping suggests the plume is pulsing, like a heartbeat," Tom Gernon, an Earth scientist at the University of Southampton, said in the statement. "These pulses appear to behave differently depending on the thickness of the plate, and how fast it's pulling apart. In faster-spreading rifts like the Red Sea, the pulses travel more efficiently and regularly like a pulse through a narrow artery." RELATED STORIES —Study reveals 'flawed argument' in debate over when plate tectonics began —There's a 'ghost' plume lurking beneath the Middle East — and it might explain how India wound up where it is today —Africa is being torn apart by a 'superplume' of hot rock from deep within Earth, study suggests Varying spacing between the stripes in different rifts suggests that the mantle plume responds differently depending on the tectonic plates above. In places where the lithosphere — the crust and upper mantle — is thicker, the mantle flow is impeded, and the striping is more condensed. Under a thinner lithosphere, the stripes are more spread out. The findings could help scientists understand volcanic activity at the surface. "The work shows that deep mantle upwellings can flow beneath the base of tectonic plates and help to focus volcanic activity to where the tectonic plate is thinnest," Keir said in the statement. Future work in the Afar region could involve investigating the rate of mantle flow beneath the various plates, Keir added.
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2 days ago
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Is Africa cracking open? How Earth's ‘heartbeat' is tearing the continent apart, forming a new ocean
A group of researchers from across the world has found that a steady, rhythmic pulse deep beneath Ethiopia's Afar region, much like a human heartbeat, is gradually tearing the continent apart. Their study of the crust and mantle beneath the region suggests that this underground activity could eventually lead to the formation of a new ocean read more The pulse is caused by molten magma pushing against the Earth's crust from below. AI Generated/Representational Image A strong, steady pulse has been found deep beneath Africa, moving like a heartbeat. This slow movement is gradually pulling the continent apart and could one day lead to the birth of a new ocean. That is what a group of researchers from around the world have said after studying the crust and mantle beneath Ethiopia's Afar region. ALSO READ | First glimpse of Sun's south pole captured: Why this is a big deal STORY CONTINUES BELOW THIS AD In areas where tectonic plates pull away from each other, the land stretches and becomes thinner. Over millions of years, it can break apart and form a new ocean basin. More from Explainers Pee power: How scientists have used urine to make dental implants In this explainer, we look at what the new study shows, what the researchers found, and how this could change the continent. What does the study say? Researchers from the University of Southampton have found a steady, rhythmic pulse deep under Ethiopia's Afar region, similar to a human heartbeat. This pulse is caused by molten magma pushing against the Earth's crust from below. Over time, this is slowly splitting the continent, and could eventually lead to the formation of a new ocean. To understand this process, the team collected over 130 samples of volcanic rock from the Afar region and the Main Ethiopian Rift. They also used existing data and advanced statistical models to study the crust and mantle beneath the surface. Active lava spilling out of the Erta Ale volcano in Afar. Image: Dr Derek Keir, University of Southampton/University of Florence For a long time, geologists believed that a hot column of rising material known as a mantle plume lay beneath Afar, helping pull the crust apart. But until now, the structure of this plume and how it behaves during rifting was not clearly understood. Emma Watts, lead author of the study and a geologist who worked on the research while at the University of Southampton, explained: 'We found that the mantle beneath Afar is not uniform or stationary—it pulses—and these pulses carry distinct chemical signatures. STORY CONTINUES BELOW THIS AD These ascending pulses of partially molten mantle are channelled by the rifting plates above. That's important for how we think about the interaction between Earth's interior and its surface." The study showed that the mantle plume under Afar contains chemical bands that repeat across the rift system, like a geological barcode. The spacing of these bands changes depending on the conditions in each section of the rift. The research was a joint effort by experts from 10 institutions, including the University of Southampton, Swansea University, Lancaster University, the Universities of Florence and Pisa, GEOMAR in Germany, the Dublin Institute for Advanced Studies, Addis Ababa University, and the GFZ German Research Centre for Geosciences. Professor Tom Gernon, a co-author of the study and Earth Science expert at the University of Southampton, said: 'The chemical striping suggests the plume is pulsing, like a heartbeat.' He added that the way these pulses behave depends on how thick the crust is and how quickly it is moving apart. STORY CONTINUES BELOW THIS AD The findings show that the plume under Afar is not fixed but reacts to the movement of the tectonic plates above. Microscope image of a thin sliver of one of the volcanic rocks from Afar. Image: Dr Emma Watts, University of Southampton/Swansea University The study, published in Nature Geoscience on June 25, explains how these plates affect the upward flow of hot mantle material. As the continent continues to split, a new ocean basin is taking shape, with seafloor spreading expected to continue along the entire rift over millions of years. With the first phase of research complete, the team will now focus on studying how the mantle is flowing beneath the surface and how fast it is moving. Is the continent splitting faster than expected? In January, Ken Macdonald, a professor at the University of California, said that the continent appeared to be breaking apart more quickly than previously thought. According to him, Somalia, along with parts of Ethiopia, Kenya, and Tanzania, could eventually separate from the rest of Africa, forming a new landmass with its own coastline. 'What might happen is that the waters of the Indian Ocean would come in and flood what is now the East African Rift Valley,' Professor Macdonald told DailyMail. Although cracks are already visible along the rift, scientists believe it will still take several million years before the continent completely splits apart. STORY CONTINUES BELOW THIS AD
