Benchmark 4C
The Physical Setting: Processes that Shape the Earth
Grades 9-12, page 74

The slow movement of material within the earth results from heat flowing out from the deep interior and the action of gravitational forces on regions of different density.

NSES Content Standard D 
Earth and Space Science: Energy in the earth system 
Grades 9-12, page 189 
The outward transfer of earth's internal heat drives convection circulation in the mantle that propels the plates comprising earth's surface across the face of the globe.