Geoscientists at the University of Toronto and Istanbul Technical University have made a new discovery in plate tectonics which shows that a large amount of damage occurs to areas of Earth’s crust long before it should be geologically altered by known plate-boundary processes.
Plate tectonics holds that the Earth’s outer shell is fragmented into continent-sized blocks of solid rock, called “plates”, that slide over Earth’s mantle. New supercomputer modelling has shown that the plates on which Earth’s oceans sit are being torn apart by massive tectonic forces even as they drift about the globe.
A microcontinent is a landmass which is not small enough to be considered an island but not big enough to be considered a continent. This research shows much earlier damage to the drifting plate further away from the boundaries of two colliding plates, focused around zones of microcontinents. This work discovers that a completely different part of the plate is being pulled apart because of the subduction process.
The researchers call the mechanism a “subduction pulley” where the weight of the subducting portion that dives beneath another tectonic plate, pulls on the drifting ocean plate and tears apart the weak microcontinent sections in an early phase of possibly significant damage.
Russel Pysklywec, a professor at U of T said,” Normally we assume – and teach – that the ocean plate conveyor is too strong to be damaged as it drifts around the globe, but we prove otherwise.”
https://phys.org/news/2021-05-discovery-geologic-plate-tectonic.html