1. Plate Tectonics

2. The Theory of Plate Tectonics Plate Tectonics: Explains how large pieces of the Earth’s outermost layer, called tectonic plates, move and change shape. A. Tectonic Plate Boundaries: A place where tectonic plates touch 1. Convergent boundary 2. Divergent boundary 3. Transform (Strike-slip) boundary

3. NOAA Plate Tectonics Video

4. I. Convergent Boundary Convergent boundary : formed by the collision of two lithospheric plates. a) Continental-continental collision:Continental-continental collision  Two plates with continental crust collide buckle and thicken to form mountain ranges.

5. Convergent Boundary b) Continental-Oceanic:Continental-Oceanic continental and oceanic plates collide. -Denser oceanic crust sinks into asthenosphere where it is recycled. Subduction Zone Subduction Zone Simulation

6. Convergent Boundary c) Oceanic-Oceanic Collisions:Oceanic-Oceanic Collisions Two oceanic plates collide. One of the plates is subducted, or sinks under the other. Subduction Zone Plate Tectonics: Subduction

7. Alaska’s Volcanic Arc

8. d. Subduction Zones  - Subduction zone is an area where a plate moves under another plate.  Usually the more dense plate is subducted.

9. Bathymetry of Subduction Analyze the image below. Answer the questions based on the image as well as your knowledge of plate tectonics. A. The topography of the seafloor indicates the presence of a convergent boundary. Where is the boundary? B. Which plate is being subducted? How can you tell? C. How did the island chain form?

10. Divergent boundaryDivergent boundary: the boundary between two tectonic plates that are moving away from each other. Ex. Mid-ocean ridges. II. Divergent Boundary

11. III. Transform boundary: boundary between tectonic plates that are sliding past each other horizontally.Transform boundary -Ex. San Andreas Fault

12. IV. Possible Causes of Tectonic Plate Motion Convection : Hot rock from deep within the Earth rises, but cooler rock near the surface sinks. -Causes lithosphere to move away from mid-ocean ridge.

14. Drilling for Core Samples  Describe how the plates are moving relative to one another.  What type of plate boundary is this? Check  What does the sea floor topography look like in this area?