Earth continuously sheds heat into space—about 47 terawatts, a fraction of what the Sun provides. This heat plays a key role in major geological processes like plate tectonics and volcanic activity. Traditionally, scientists believed that this heat rises slowly through mantle convection, much like steam from a pot of soup.
However, a fresh study suggests some heat travels faster through structures known as mantle plumes. This idea, introduced by W. Jason Morgan in 1971, has now been reinforced by recent findings.
Researchers have identified a “ghost plume” that lies beneath the deserts of Oman, where there’s no visible volcanic activity. Lead investigator Simone Pilia from King Fahd University of Petroleum and Minerals analyzed thousands of earthquake signals and named the plume the “Dani plume,” after his son.
Typically, mantle plumes create surface features like the Hawaiian islands or Yellowstone National Park. The Dani plume, however, is different; it lacks recent lava flows. It’s hot enough to soften rock but not hot enough to break through the thick crust above. Pilia confirms, “The evidence kept pointing us toward this being a plume.” They tracked the structure to depths of at least 410 miles, where seismic activity illustrated a column about 125 miles wide.
The study used seismic tomography, akin to a CT scan but for Earth. Vibrations from earthquakes help create 3D maps of speed variations, revealing temperature differences that imply heat signatures. In Oman, researchers found temperature increases of 200-500°F, enough to affect rock but still below the melting point.
Saskia Goes from Imperial College London, who reviewed the study, finds the evidence convincing, noting that imaging such narrow columns can be challenging.
Even though there’s no lava, characteristics of the surface tell a different story. The Salma Plateau in Eastern Oman stands unusually high at over 6,500 feet despite minimal geological activity. Studies show this area continues to rise slightly. This uplift likely stems from the hot mantle plume beneath, similar to the situation in Yellowstone, which is actively volcanic.
Geological analysis also hints that the Dani plume may have influenced India’s movement about 40 million years ago. It’s proposed that the plume’s movement caused a subtle shift in the Indian Plate. The study’s calculations reveal that even a plume this size can exert considerable force.
The Dani plume could change how we understand Earth’s heat budget. If numerous plumes like this one exist, more heat might be released from the Earth’s core than previously thought. This finding could alter our expectations about how long Earth’s internal systems will function.
Future research, including ocean-bottom seismometers and satellite gravity studies, might reveal additional hidden plumes. Such discoveries could improve models connecting deep Earth movements to surface phenomena, and they could highlight the interconnectedness of deep geological features.
The research published in Earth and Planetary Science Letters underscores that the Dani plume and the Afar plume—beneath the Horn of Africa—might trace back to the same vast reservoir. This leads to the idea that multiple mantle plumes could be part of extensive networks, reshaping our understanding of how geological activity on the surface is interconnected across continents.
By broadening our approach to detecting mantle plumes, we can uncover more hidden geological processes that shape our planet, changing how we perceive heat flow from the core to the surface.
