Hidden Plumes in Earth’s Mantle May Drain Heat from the Core

Researchers have discovered the first known “ghost plume” beneath Oman, suggesting a column of hot rock rising from the lower mantle with no visible volcanic activity on the surface.

The mantle plume is a mysterious intrusion of molten rock believed to transfer heat from the core-mantle boundary to the Earth’s surface, sometimes occurring beneath the heart of continental plates, as seen in regions like Yellowstone and East Africa. Notably, “these scenarios typically feature surface volcanoes,” states Simone Pilia from King Fahd University of Petroleum and Minerals in Saudi Arabia. Oman lacks such volcanic indicators.

Pilia first hypothesized the existence of this “accidental” plume while examining new seismic data from Oman. The analysis revealed that seismic waves from distant earthquakes travel more slowly through a cylindrical region beneath eastern Oman, indicating it is less dense than surrounding materials due to elevated temperatures.

Additional independent seismic assessments identified critical boundaries where Earth’s deep minerals undergo changes that align with the hot plume’s characteristics. This evidence suggests the plume extends over 660 km from the surface.

The presence of these plumes also explains why the region continues to elevate despite geological compression, a process where the crust is squeezed together. This discovery fits models that explain alterations in Indian tectonic plate movements.

“The more evidence we collected, the more convinced we became it was a plume,” remarks Pilia, who has named this geological feature the “Dinni plume” after her son.

“It’s plausible that this plume exists,” agrees Saskia Goes at Imperial College London, adding that this study is “thorough.” Nevertheless, she emphasizes that identifying narrow plumes is notoriously challenging.

If verified, the existence of a “ghost plume” trapped within Oman’s relatively thick rocky layers suggests there might be others. “We are confident that the Dinni plume is not alone,” says Pilia.

If multiple hidden plumes exist, it could indicate that heat from the core is transferring more readily through the mantle in these regions, influencing our understanding of Earth’s evolutionary history.