CONCEPT 3: TECTONIC PLATE MOVEMENT

• Tectonic Plates can move 1-10 cm per year
• Earths mantle is partially melted material
• Energy from radioactive decay of some elements in Earths interior and core heat up parts of the mantle
• Convection currents are thought to drive tectonic plate motion
• mantle convection: where warmer, less dense material rises to the surface
• cooler dense material sinks
• mantle convection causes large convection currents in the mantle
• as the mantle material moves it drags the tectonic plates with it
• ridge push and slab pull are two processes that result from mantle convection
• ridge push and slab pull contribute to the movement of tectonic plates
• ridge push: where new material pushes older material aside, causing tectonic plates to move apart
• with ridge push, rising material spreads out as it reaches the upper mantle- causes lithosphere to lift and push plates apart and divergent plate boundaries
• slab pull: pulling of a tectonic plate due to gravity and subduction
• with slab pull, as leading edge of subducting plate sinks, it pulls rest of the plate with it at convergent plate boundaries