Plates Move

Plates move Plates are what move They move what is on top of them Crust is on top of the plates Continental Crust- The crust that makes up continents/land Oceanic Crust- The crust that makes up the oceans

Divergent Boundary Plates move apart Most are found in the ocean Mid-ocean ridges are found where this happens In the ocean they move apart and riff valleys form This is how continents split apart New crust is formed

Process 1. Hot material rises from the mantle 2. The heat causes the crust to bulge upward 3. The crust cracks, and a riff valley is formed 4. Magma rises, the continent splits apart

Transform Boundaries Plates move past each other in opposite directions Crust is not formed or destroyed Occur mostly at the sea floor but can form on land too San Andreas Fault

Convergent Boundary Plates push together 3 different types Continental-continental collision Oceanic-oceanic collision Oceanic- continental collision Crust is destroyed or folded

Continental- Continental Collisions Two continental plates collide Each plate is the same density No plates can sink, so it has to collide Mountains are made when the two plates run into one another EX: Rocky Mts.

Oceanic- Continental Collision A piece of oceanic crust runs into a piece of continental crust Oceanic crust sinks Deep-ocean trenches Costal mountains EX: Andes Mts.

Oceanic-Oceanic Collision 2 plates run into one another The older plate will sink under the newer plate Subduction- When one plate sinks beneath another The plate moves into earth, and melts Forms Deep ocean trenches- deep canyons on the ocean floor Island arcs- volcanic islands EX: Hawaii

Hot Spot Heated rock rise in plumes, are thin columns from the mantle The magma eventually hardens The magma could have risen so high that it peaks out of the water More islands will form in an arc, this shows how the plate is moving EX: Hawaii

Review In what direction do plates move in convergent boundaries? A. Towards each other B. Away from each other C. Depends on stress D. Past each other

Review In what direction do plates move in transform boundaries A. Towards each other B. Away from each other C. Depends on stress D. Past each other

Review In what direction do plates move in divergent boundaries A. Towards each other B. Away from each other C. Depends on stress D. Past each other

Review What feature occurs at a divergent boundry A. Island arc B. Riff valley C. Mountains D. surface fault

Review The Andes Mountains in South America occur at what type of boundary? A. Continent-continent convergent boundary B. Continent-oceanic convergent boundary C. Divergent boundary D. Transform boundary