Deep beneath Earth’s surface, hot mantle rock slowly rises, fueling massive volcanic activity, tearing continents apart, and opening new oceans. But where these upwellings form, what they’re made of, and how shifting tectonic plates shape them still remains a puzzle.
The Afar region in East Africa is a rare geological crossroads—a triple rift zone where three tectonic plates are pulling away from each other. Scientists think a rising plume of hot mantle lies below it, offering a unique chance to study how such forces reshape our planet from the inside out.
Deep under Africa, scientists from the University of Southampton have found that hot mantle rock is rising in steady pulses—almost like the Earth has a beating heart. This hot material is pushing up beneath the Afar region in Ethiopia, slowly pulling the continent apart and setting the stage for a brand-new ocean.
The research shows that this rising heat is shaped by the movement of tectonic plates—huge slabs of Earth’s crust that float above the mantle. As these plates stretch and thin over time, especially at places like Afar where three rifts meet, they eventually split. That split is how a new ocean begins to form.
An unexpected distortion in the world’s largest continental rift
Beneath the Afar region, the mantle isn’t just sitting still—it pulses upward in bursts, each carrying its own chemical fingerprint. These rising plumes of hot, partially melted rock are steered by the rifting tectonic plates above, showing a tight link between Earth’s deep interior and surface activity.
To better understand this hidden process, researchers gathered over 130 volcanic rock samples from Afar and the Main Ethiopian Rift. Combined with past data and advanced modeling, the analysis helped them map the structure of the crust and mantle—and reveal what’s brewing inside.
Beneath the Afar region lies a single, lopsided plume of hot mantle rock, patterned with repeating chemical bands—like Earth’s own barcode. These stripes shift in spacing based on how each rift arm is stretching, revealing that the plume pulses upward like a heartbeat.
According to Professor Tom Gernon from the University of Southampton, these pulses move differently depending on the overlying plate. In fast-spreading areas like the Red Sea, they rise more smoothly, like blood through a narrow artery.
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The study paints a vivid picture of a living, breathing Earth interior—one that responds actively to the movement of tectonic plates above it.
Dr Derek Keir, Associate Professor in Earth Science at the University of Southampton and the University of Florence, and co-author of the study, said: “We have found that the evolution of deep mantle upwellings is intimately tied to the motion of the plates above. This has profound implications for how we interpret surface volcanism, earthquake activity, and the process of continental breakup.”
“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. Follow on research includes understanding how and at what rate mantle flow occurs beneath plates.”
Journal Reference:
- Watts, E.J., Rees, R., Jonathan, P. et al. Mantle upwelling at Afar triple junction shaped by overriding plate dynamics. Nat. Geosci. (2025). DOI: 10.1038/s41561-025-01717-0
