New research explains what happens when a tectonic plate disappears inside the Earth.
In the study published in Nature, a team of researchers from the University of Texas explains that the plates weaken significantly as they sink, but they affirm that they do not break completely.
How did they find out?
To make this finding, the researchers used 2D computer models of the subduction zones and programmed them using known physics about the behavior of materials.
They then looked at the model to see what was happening in the subduction zone and compared the results with real-world observations.
These models suggest that when a plate dips under another, the descending piece (or slab) bends sharply downward and cracks. This bending also causes the grains on the bottom of the plate to become finer and weaker.
The pressures left the plate almost intact, but with several weak points.
According to scientists, this means that the plates do not break and keep pulling on the parts behind for a long time. In fact, the plate can continue to slide under the other plate for hundreds of millions of years.
The simulations match deep seismic observations and images showing weakened areas of a subduction zone in Japan.
“Personally, I think there are many good arguments for plate tectonics to be much older,” explains study author Thorsten Becker.
“But the mechanism revealed by our model suggests that things might be more sensitive to mantle temperature than we think, and I think it could lead to interesting new avenues of discussion.”