However, the reasons for this softening are not well understood. Scientists previously thought that molten rocks might be a factor. But this study shows that the melt does not, in fact, significantly affect the flow of mantle rocks.
“When we think about melting something, we instinctively think that the melt should play a large role in the viscosity of the material,” said Junlin Hua, a postdoctoral fellow in UT’s Jackson School of Geosciences, who led the research. Did. “But what we found is that while the melt fraction is quite high, its effect on mantle flow is modest.”
The heat and rock in the mantle is the prevailing influence on the movement of convective plates, according to research Hua began as a graduate student at Brown University. Although Earth’s interior is largely solid, over long periods of time, rocks can move and flow like honey.
Showing that the molten crust has no effect on plate tectonics is a less intriguing variable for computer models of Earth, said co-author Thorsten Becker, a professor at the Jackson School.