1. Possible Causes of Tectonic Plate Motion

2. Three Possible Driving Forces
Convection
Slab Pull
Ridge Push

3. Convection
Hot, less dense material rises while cooler, more dense material sinks.
The hot material cools and the cool material warms up and the cycle continues.
As the mantle moves, tectonic plates are dragged sideways.
*Mantle

4. Slab Pull Oceanic lithosphere is more dense than the asthenosphere.
When the edge of the oceanic plate sinks, the rest of the plate is pulled with it.
*Subduction zones

5. Ridge Push
Oceanic lithosphere is higher at the ridge than where it sinks beneath continental lithosphere.
Oceanic plates slide down the lithosphere-asthenosphere boundary during ridge push.
*Divergent boundaries

8. How far do they move?
Tectonic plates move just centimeters per year