Plate Boundaries Divergent, Convergent and Transform Plate Boundaries

Divergent Plate Boundaries Move away from each other Magma upwells and solidifies = new basalt Constructive plate boundary –Rid-ocean ridge created – new denser material rises –65,000 km long, 1500 km wide –Causes earthquakes and volcanoes

Convergent Plate Boundaries Two plates moving towards one another Collide Destructive plate boundaries

3 types of convergent plate boundaries 1. oceanic- continental convergence – ocean plate (more dense) goes under continental plate Subduction Forms trench Earthquakes Volcanoes form on continental plate

2. oceanic-oceanic convergence – oldest, densest plate of the two is subducted Volcanoes form on ocean floor – islands can be created E.g Japan

Transform Plate Boundaries Lithosphere neither created or destroyed Conservative plate boundary Most common Transform faults Join ridges to trenches & trenches to trenches

But what makes the plates move? CONVECTION –Cold material is denser and will sink –Warm material is less dense, will rise –E.g boiling water

Assignments Divergent plate boundaries Read – P “divergent plate boundaries” P “The mid ocean ridge” (p my book) Convergent Plate Boundaries Read (P 97 my book) Transform plate boundaries Read (p my book) Convection Read (p my book)