Scientists from the University of California at San Diego have discovered a “lubricant” for Earth’s tectonic plates.
According to scientists at Scripps Institution of Oceanography, a layer of liquefied molten rock in the Earth’s mantle may be acting as a lubricant for the sliding motions of the planet’s gigantic tectonic plates. This finding could help scientists better understand the fundamental geological functions of the planet, as well as improve their knowledge of volcanism and earthquakes.
The scientists found the layer of liquefied molten rock at the Middle American trench offshore Nicaragua. They utilized seafloor electromagnetic imaging technology to image a 15.5-mile-thick layer of partially melted mantle rock below the edge of the Cocos plate where it moves underneath Central America.
Scientists obtained the images during a 2010 expedition aboard the research vessel Melville. After using several seafloor instruments to map features of the crust and mantle, the scientists learned that they had discovered magma in a “completely unexpected” place.
According to Kerry Key, an associate research geophysicist at Scripps, scientists began with the goal of examining how fluids interact with plate subduction, but instead located a melt layer.
Prior to this discovery, scientists were unsure exactly what forces allowed the planet’s tectonic plates to move across the Earth’s mantle. Though studies have revealed that dissolved water in mantle minerals leads to a more ductile mantle that would aid tectonic plate motions, scientists have failed to come up with the data and images to confirm or deny this theory.
Lead author Samer Naif, a graduate student, notes that their data rules out water as the force that allows the planet’s tectonic plates to slide across the Earth’s mantle. The images obtained during the 2010 expedition suggest that “some amount of melt in the upper mantle” is “creating this ductile behavior for plates to slide.”
Key contends that that their findings will help scientists learn more about the plate boundary, which could ultimately improve their understanding of earthquakes.
Now, researchers are looking for the source that generates the magma in the layer of liquefied molten rock in the Earth’s mantle.
The study’s findings will be described in detail in the journal Nature.