A convecting mantle is an essential feature of plate tectonics and contributes to the formation of both igneous and metamorphic rocks. Where does the thermal energy that drives these convection currents come from?
A) The convection of the mantle is driven by the heat gradient within the mantle layer itself.
B) The convection of the mantle is a product of the transfer of heat from the core to the lower mantle.
C) The convection of the mantle is the result of the radioactive decay of nickel occurring within the core.
D) The heat is the frictional heat from the rotating fluids within the core of the Earth which rises up into the mantle.