Heat from Earth's core drives movement.

• Position: Tectonic Plates

For decades, scientists have theorized that the movement of Earth's tectonic plates is driven largely by negative buoyancy created as they cool. New research, however, shows plate dynamics are driven significantly by the additional force of heat drawn from the Earth's core, which also challenges the theory that underwater mountain ranges, known as mid-ocean ridges, are passive boundaries between moving plates.

The findings show the East Pacific Rise, the Earth's dominant mid-ocean ridge, is dynamic as heat is transferred. Researchers came to the conclusions by combining observations of the East Pacific Rise with insights from modeling of the mantle flow there. The findings were published in Science Advances.

"We see strong support for significant deep mantle contributions of heat-to-plate dynamics in the Pacific hemisphere," says geophysical scientist David B. Rowley, lead author of the paper. "Heat from the base of the mantle contributes significantly to the strength of the flow of heat in the mantle and to the resultant plate tectonics."

The researchers estimate up to approximately 50% of plate dynamics are driven by heat from the Earth's core and as much as 20 terawatts of heat flow between the core and the mantle.

Unlike most other mid-ocean ridges, the East Pacific Rise as a whole has not moved east-west for...