Ways that convection might move plates 1. Geophysicists who study this issue conclude that convection currents in the mantle is the fundamental driving force. Convection occurs because of unveven distribution of heat sources in the mantle. Hot currents rise because they are less dense than the surrounding mantle.
Currents move laterally, loose heat and cool, then sink.
As we discussed earlier, the largest source is the decay of radioactive elements. Although convection is the fundamental driving force for plate motions, how it works in detail is somewhat controversial. Because of this elevation, they slide by gravity away from spreading centers. In fact, Wegener's proposals for the sequence of drifting continents over the past 250 million years fit very well with our current understanding of the history of lithospheric plate motions and the age of the sea floor. Prior to 225 m.y.a.