Scientists have long known about the push and pull effects that drive the tectonic plates across the surface of our planet, but new research shows that there might be a third force inflicting its presence on the movement of the continental plates.
Scientists at Scripps Institution of Oceanography at UC San Diego have found that plumes of hot magma which push up from the Earth’s deep interior may also have an effect on continental plate movement.
Using analytical methods to track plate motions throughout Earth’s history, Scripps scientists Steve Cande and Dave Stegman were able to show that mantle plume “hot spots” – which can last for tens of millions of years, and are currently active today underneath Hawaii, Iceland and the Galapogos – was responsible for the movement of the Indian plate around 70 million years ago.
Their results show that with the arrival of the powerful mantle plume head underneath, the Indian plate suddenly sped up. The arrival of the plume also created what is today known as the Deccan flood basalts in western India, massive formations of volcanic rock, which erupted just prior to the mass extinction of the dinosaurs.
The plume is still working today, even though India has moved on and collided with Asia, and has most recently formed Réunion island near Madagascar.
The scientists also believe that the “plume push” which sped the Indian plate also had an effect on the African plate, pushing it in the opposite direction.
“Prior to the plume’s arrival, the African plate was slowly drifting but then stops altogether, at the same time the Indian speeds up,” explains Stegman, an assistant professor of geophysics in Scripps’ Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics. “It became clear the motion of the Indian and African plates were synchronized and the Réunion hotspot was the common link.”
After the force of the plume had waned, the African plate’s motion gradually returned to its previous speed while India slowed down.
“There is a dramatic slowdown in the northwards motion of the Indian plate around 50 million years ago that has long been attributed to the initial collision of India with the Eurasian plate,” said Cande, a professor of marine geophysics in the Geosciences Research Division at Scripps. “An implication of our study is that the slowdown might just reflect the waning of the mantle plume—the actual collision might have occurred a little later.”
Source: University of California – San Diego
Image Source: Scripps Institution of Oceanography at UC San Diego