Even as the theory of plate tectonics was first being proposed in the 1960s, scientists realized that there was a major problem with the theory:  Its two main components seemed to operate independently.


One component was the slow movement of the rigid plates, presumably driven by great convection cells within the mantle.  The other was a system of giant plumes that were rising up from deep inside the Earth up to the surface and were responsible for long lines of volcanoes, such as those of the Hawaiian Islands and the line of explosive volcanoes that run from southeastern Oregon to northwestern Wyoming and that end at Yellowstone.


The problem with the theory is being resolved by abandoning the idea of giant convection cells within the mantle being driven by heat and by replacing it with subduction of huge tectonic slabs that churn the mantle.


These huge slabs are oceanic tectonic plates that are being pulled down into a hot and viscous mantle by gravity.  It is the downward sliding of these huge slabs that pulls on the plates and causes them to move across the Earth’s surface.


These slabs are accumulating as megapiles atop the core-mantle boundary.  As they accumulate, there is a reverse upward-flow of the mantle as giant plumes that rise up to the surface and supply heat to the volcanoes of Hawai’i and at Yellowstone.