New Research Reveals Mantle Plume Dynamics Under Ethiopia's Afar Region

In a groundbreaking study, scientists have discovered that a rhythmic mantle plume beneath the Afar Depression in Ethiopia is contributing to the gradual formation of a new ocean, reshaping the geological landscape of East Africa. This research, conducted by a team from the University of Southampton and published in the journal Nature on June 27, 2025, provides a clearer understanding of how mantle upwellings interact with tectonic plate movements, further unraveling the complexities of continental breakup.

The Afar Depression is unique in that it is one of the few locations worldwide where three divergent tectonic plate boundaries intersect: the Main Ethiopian Rift, the Red Sea Rift, and the Gulf of Aden Rift. This geological setting has long intrigued scientists, who have suspected the presence of a mantle upwelling, a phenomenon where heat from deep within the Earth causes rock to rise toward the surface. However, the specific characteristics of this upwelling remained largely unknown prior to this study.

Dr. Emma Watts, the lead author of the study and a researcher at Swansea University, stated, "We found that the mantle beneath Afar is not uniform or stationary; it pulses, and these pulses carry distinct chemical signatures." By analyzing lava samples from over 130 volcanoes in the region, the researchers identified that the mantle upwelling is asymmetrical, characterized by various plumes of hot mantle material. This indicates that the rising mantle material is influenced by the dynamic movements of the tectonic plates above it, which are stretching and thinning the crust, thereby facilitating the upward movement of hot material.

Co-author Dr. Tom Gernon, a professor at the University of Southampton, likened the behavior of the mantle plume to a heartbeat. He explained that the pulsating nature of the plume varies depending on the rate of tectonic plate movement. In areas where the plates are moving apart quickly, such as the Red Sea Rift, the mantle flow is more concentrated; conversely, in regions of slower movement, the flow is more diffuse.

The interaction between the mantle plume and tectonic activity has significant implications. As the lithosphere—the Earth's rigid outer layer—is eroded from below, it becomes thinner, sometimes reaching 15 kilometers in depth in certain areas. This thinning, combined with the stretching caused by tectonic forces, leads to increased volcanic activity, as evidenced by ongoing eruptions in the Erta Ale volcano and seismic swarms in the region.

Derek Keir, a co-author affiliated with both the University of Southampton and the University of Florence, emphasized the importance of understanding these mantle dynamics, stating, "We have found that the evolution of deep mantle upwellings is intimately tied to the motion of the plates above," which subsequently influences surface volcanism, earthquake activity, and the overall process of continental breakup.

Looking forward, the researchers intend to further investigate how mantle flow beneath tectonic plates directs volcanic activity. Their findings suggest that the ongoing mantle upwelling in the Afar region could eventually lead to the formation of a new ocean, similar to the historical separation of the Atlantic Ocean from Europe and North America.

This research not only enhances our understanding of East African geology but also provides insights into broader geological processes, including the potential causes of past climatic upheavals and mass extinctions linked to large igneous provinces. The study's findings underscore the interconnectedness of Earth's internal processes and surface phenomena, illustrating a complex relationship that continues to shape our planet's geological history.