PLATE BOUNDARIES plate boundaries.com.pptx

plates

1. PLATE BOUNDARIES

2. Divergent Convergent Transform Three types of plate boundary

3. Spreading ridges As plates move apart new material is erupted to fill the gap Divergent Boundaries

4. Divergent Boundary Plates are moving apart Occurs at Mid-ocean Ridges and at Rift Valleys ( seafloor spreading ) Rift valley = deep valleys at the center of a mid-ocean ridge. Volcanic activity (underwater) and earthquakes take place along this boundary. Hot springs also come up from hydrothermal vents on the ocean floor.

5. Convergent Boundary Plates are moving toward each other. 2 Types of Convergent Boundaries Subduction Collision

6. Convergent Boundary Subduction occurs at: ocean to ocean plate moving toward each other Ocean to continental plates moving toward each other Oceanic crust is denser than continental crust, so oceanic crust will subduct underneath the continental plate Deep sea trenches are formed Volcanic island arcs are formed Earthquakes occur

7. Convergent Boundary - Subduction Islands of Indonesia (ocean to ocean) Mariana Islands (ocean to ocean) Mariana Trench (Pacific plate moving underneath the Philippine Plate)

8. Convergent Boundary Collision Boundary occurs at: Continental to continental plate moving towards each other Builds high mountain chains Earthquakes occur along these boundaries

9. Forms mountains, e.g. European Alps, Himalayas Continental-Continental Collision

10. Oceanic lithosphere subducts underneath the continental lithosphere Oceanic lithosphere heats and dehydrates as it subsides The melt rises forming volcanism E.g. The Andes Subduction

11. When two oceanic plates collide, one runs over the other which causes it to sink into the mantle forming a subduction zone . The subducting plate is bent downward to form a very deep depression in the ocean floor called a trench . The worlds deepest parts of the ocean are found along trenches. E.g. The Mariana Trench is 11 km deep! Ocean-Ocean Plate Collision

12. Where plates slide past each other Transform Boundaries Above: View of the San Andreas transform fault

13. Transform Boundary 2 plates are sliding past each other. Earthquake activity occurs here

14. Transform Boundary San Andreas Fault (in California) Movement isn’t the same along all parts of the fault. Some parts can move up to 5cm/yr, while others haven’t moved in over a century. North Anatolian Fault (in Turkey) Fracture zones along mid-ocean ridges