Deep magma tagged as tectonic factor

SAN DIEGO, July 7 (UPI) -- U.S. researchers say they've identified a force driving Earth's massive tectonic plates, a movement that can build mountains or trigger massive earthquakes.

Scientists have known for decades that the ongoing movements and collisions of the plates, a so-called push/pull mechanism, are responsible for sculpting continental features around the planet, usually where plates are either moving apart or coming together. Now researchers at the Scripps Institution of Oceanography at the University of California, San Diego, have discovered a force that drives plate tectonics: plumes of hot magma pushing up from Earth's deep interior.

Steve Cande and Dave Stegman say their research provides evidence that such mantle plume hot spots, which can last for tens of millions of years and are active today at locations such as Hawaii, Iceland and the Galapagos, may work as an additional tectonic driver along with known push-pull forces.

The rise of a powerful mantle plume around 70 million years ago contributed to a rapid motion of the Indian plate that was pushed as a consequence of overlying the plume's location, they said.

The Indian continent has since drifted north and collided with Asia, but the original location of the plume's arrival has remained volcanically active to this day, most recently having formed Reunion Island near Madagascar, they said.

This "plume-push" force acted on other tectonic plates, pushing on Africa as well but in the opposite direction, they said.