Incredible Force Deforms Earth's Inner Layers: The 'Phantom Plume' of the Planet is to Blame 0 14

The Earth emits about 47 terawatts of heat into space — a negligible amount compared to solar radiation, but vital for plate tectonics, volcanoes, and the magnetic field. It is generally believed that this flow rises slowly due to mantle convection, similar to steam seeping through thick soup. However, the results of a new study contradict this theory, writes Focus.

A new study conducted by a team from King Fahd University of Petroleum and Minerals suggests that some of the heat travels through high-speed channels known as mantle plume columns. It is worth noting that this concept was first proposed by Jason Morgan back in 1971.

Now, researchers report the first "phantom plume" with no signs of surface volcanism, hidden beneath the eastern deserts of Oman. During the study, lead author Simone Pilia and colleagues analyzed thousands of earthquake signals and named the buried column the Dani plume in honor of his son.

Typical plumes are known to reach the surface and form geological features such as Hawaii or Yellowstone, but there are no fresh lava fields in Oman. This absence makes the Dani plume a ghost: hot enough to soften rock but not hot enough to break through the thick continental layer.

According to Pilia, the more evidence they and their colleagues gathered, the more convinced they became that they were looking at nothing other than a plume. The team traced the column to a depth of at least 660 kilometers, where seismic waves slowed down, forming a neat cylinder about 200 kilometers wide. Independent checks also showed that the transition zone of the mantle was deformed downward at a depth of 410 kilometers and then rose again at a depth of 660 kilometers, creating a classic thermal signature of rising material.

The team used seismic tomography — the Earth’s equivalent of computed tomography, which converts earthquake vibrations into three-dimensional speed maps. An increase in temperature of about 93°C can reduce the speed of shear waves by about 3%.

The results indicate that in Oman, the speed of shear waves within the column decreased by this amount, indicating an excess temperature of about 93–260°C. This is enough to soften peridotite but still below the melting threshold under a lithosphere of 209 kilometers thick.

Scientists also note that even without lava, there are surface signs of this phenomenon. The Salma Plateau in eastern Oman is remarkably high, exceeding 1980 meters in elevation, despite only a slight reduction in the Earth's crust.

GPS navigation and coastal studies show that the coastline continues to rise at a rate of less than 0.1 centimeters per year. The simplest explanation for this is dynamic support from the hot, buoyant mantle below. Notably, a similar uplift is observed in the Yellowstone area, where the well-known plume fuels long-lived volcanic and hydrothermal activity in the western United States.

The team also used geological reconstructions indicating that the Dani plume was beneath the Indian Plate about 40 million years ago, coinciding with a slight bend in the trajectory of India moving eastward. Pilia and colleagues argue that the viscous resistance of the plume flow pushed the plate, like a hidden hand.

The Dani plume is also significant for Earth's thermal balance. The more such columns bypass slow mantle convection, the more heat, than expected, comes directly from the core, potentially reducing estimates of how long the internal dynamo can continue to operate.