3 Movements at plate boundaries Plate Tectonics 3 Movements at plate boundaries

Divergent boundaries Plates are moving apart As plates move apart, new crust forms Cause of movement is convection cells in mantle Mid ocean ridges are divergent boundaries where seafloor spreading occurs – an example is the Mid-Atlantic Ridge. Rift valleys are divergent boundaries on land – The Great Rift Valley in east Africa is an example of a continent breaking apart. The Red Sea is a part of the rift.

Convergent plate boundaries Two plates are colliding or moving together Old crust is being deformed or destroyed(melted) due to collision At convergent zone one of two things can happen Oceanic plate crust can be forced down underneath less dense continental or oceanic crust, forming a deep ocean trench at the subduction zone. Ex: Aleutian trench south of Alaska Continental plates colliding cause rocks to fold and break, creating mountain ranges Ex: Himalaya mountains where India collides with Asia

Transform Boundary Two plates sliding past each other. Crust is neither created nor destroyed (side swipe) Example: San Andreas fault in S. Calif between the N. American and Pacific plates