Mantle Plumes May Crack Earth's Continents Under Weak Stress

Plumes from Earth's mantle may just break up entire continents. Scientists have taken a closer look at the material rising up from the boundary layer of Earth's core and have found that they can help shape our planet's surface.

In some parts of the Earth, material rises upward like a column to just below Earth's crust hundreds of kilometers above. Halted by the resistance of the hard crust and lithospheric mantle, the flow of material becomes wider and takes on a mushroom-like shape, forming a mantle plume. These plumes can actually create volcanoes outside of tectonically active areas. Yet it seems that they also may have a role in the alteration of continents.

The scientists created a new computer model and conducted numerical experiments to reproduce the Earth's surface in high-resolution 3D. Then, the scientists created simulations, allowing plumes to hit an unstressed plate. This didn't cause the plate to break, but merely caused it to form a round hump. Yet the simulations did show that the rising flow of material is actually strong enough to cause continental breakup if the tectonic plate is under weak tensile stress.

"The process can be compared to a taut piece of plastic film," said Taras Gerya, one of the researchers, in a news release. "Weak, pointed force is enough to tear the film, but if the film is not pulled taut, it is extremely difficult to tear."

Despite the new findings, though, the idea of mantle plumes is still widely disputed, and some researchers deny that they even exist. Yet the new models do provide new evidence that seems to indicate that they are present.

"I think it is much more likely that they do exist," said Gerya. "So far, we have only been able to observe the effects that plumes have on the Earth's surface and on the propagation of seismic waves in the Earth's interior."

The findings are published in the journal Nature.