1. Plate Tectonics

2. The Earth’s crust is divided into 12 major plates which are moved in various directions. Earth’s plates float on top of mantle similar to ice cubes in a bowl of water

3. Tectonic Plates

4. “Plates” of lithosphere are moved around by the underlying hot mantle convection cells.

5. Different Types of Boundaries

6. Sea-floor spreading: process by which new ocean floor is formed

7. Many rift valleys form at divergent plate boundaries
Many rift valleys form at divergent plate boundaries. The depression created by the rifting plates is the rift valley.

8. Divergent Boundary – Arabian and African Plates
Arabian Plate
Red Sea
African Plate

9. Mid-oceanic ridges – divergent boundary in the middle of the ocean; forms new sea floor.
underwater mountain chains that run through the Earth’s Basins
Magma rises to the surface and solidifies and new crust
forms
Older Crust is
pushed farther
away from the
ridge

10. Divergent Boundary – Iceland

11. Convergent Boundary
Forms mountains, e.g. European Alps, Himalayas

12. Eurasian Plate
Indian Plate
Himalayan Mountains

13. Subduction: At a convergent boundary where continental crust pushes against oceanic crust, the oceanic crust which is thinner and more dense than the continental crust, sinks below the continental crust.

14. Transform Boundary: place where two tectonic plates slide past each other horizontally