1. Plate Tectonics

2. III. 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. Convergent Boundary Convergent boundary : formed by the collision of two lithospheric plates. 3 types: a) Continental-continental collision: Continental-continental collisionContinental-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

6. c) Oceanic-Oceanic Collisions: Oceanic-Oceanic CollisionsOceanic-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

9. Subduction Zones -Subduction zone is an area where a plate moves under another plate. -Subduction zone is an area where a plate moves under another plate. The Crust is recycled and causes volcanic activity. The Crust is recycled and causes volcanic activity. Subduction zones are normally located at deep ocean trenches. Subduction zones are normally located at deep ocean trenches.

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

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

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

15. B. Possible Causes of Tectonic Plate Motion Convection: Hot rock from deep within the Earth rises, but cooler rock near the surface sinks. 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.