According to a study led by researchers at the University of Southampton, these pulses are gradually tearing apart the African continent, resulting in the formation of a new sea basin.
Variation of geochemical and geophysical properties around distant triangles. Image credit: Watts et al, doi: 10.1038/s41561-025-01717-0.
The AFAR region stands out as a unique site on Earth where three structural lifts converge: the main Ethiopian rifts, the Red Sea rifts, and the Gulf of Aden lifts.
Geologists have speculated for some time that a thermal upwelling from the mantle, commonly referred to as plumes, exists beneath this area and promotes the extension of the crust along with the formation of upcoming sea basins.
However, the details regarding the structure of this upwelling and its behavior beneath the lifting plate have remained largely unknown until now.
“Our findings indicate that the mantle below the region is uniform but not stationary; it exhibits a pulsing nature that carries a unique chemical signature,” explained Dr. Emma Watts, who led the study at the University of Southampton and is currently at Swansea University.
“These rising pulses from the partially melted mantle are directed by the overlying filling plate.”
“This insight is crucial for understanding the interaction between the Earth’s interior and its surface.”
Dr. Watts and her team collected over 130 volcanic rock samples from remote areas and significant Ethiopian rifts.
Additionally, they utilized existing data and sophisticated statistical modeling to examine the structure of the crust and mantle, along with the melts within.
Their research reveals a single asymmetric plume beneath the distant region, showcasing distinct chemical bands that recur throughout the lift system, akin to geological barcodes.
These patterns vary in spacing according to the structural conditions of each lift arm.
“The observed chemical stripes imply that the plume pulsates like a heartbeat,” remarked Professor Tom Gernon from the University of Southampton.
“These pulses seem to behave differently based on the thickness of the plate and the rate at which it is pulled apart.”
“In faster-spreading rifts like the Red Sea, the pulsation occurs more efficiently and regularly, similar to a pulse flowing through a narrow artery.”
The findings illustrate that the mantle plume beneath the distant region is dynamic, reacting to the tectonic plate above it.
Dr. Derek Kiel, a researcher at the University of Southampton and the University of Florence, stated:
“This has significant implications for interpreting processes related to surface volcanism, seismic activity, and continental splitting.”
“Our work indicates that deep mantle upwellings flow beneath the tectonic plate, concentrating volcanic activity in the thinnest areas.”
“Understanding the rate and manner of mantle flow beneath the plate is crucial for further research.”
“Collaborating with experts from various fields within the institution, as we did for this project, is vital for uncovering the processes that occur beneath the Earth’s surface and their link to recent volcanic activity,” Dr. Watts emphasized.
“It’s challenging to see the broader picture, akin to assembling a puzzle without all the pieces unless we employ diverse techniques.”
study published in the journal Natural Earth Science.
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ej watts et al. Mantle upwelling at an afor triple junction influenced by the dynamics of the overriding plate. Nat. Geosci Published online on June 25, 2025. doi:10.1038/s41561-025-01717-0
Source: www.sci.news
