• Tectonic cycle – Movements/ interactions by which rocks are cycled from the mantle to the crust and back – Includes earthquakes, volcanism, and plate motion, driven by convection in the mantle – As a result, seafloor recycles itself every 200 million years • Earth’s internal heat – Conduction • Slow release of heat – Convection • A form of heat transfer in which hot material circulates from hotter to colder regions, looses its heat, and then repeats the cycle