Plate Boundaries

The theory of plate tectonics is based on the understanding that Earth's lithosphere is broken into separate plates which float on top of the moving asthenosphere. Further, we believe that movement of convection currents in the asthenosphere drives the movement of the tectonic plates. Because all the plates are moving at the same time, they interact with each other in different ways, overlaping, seperating, and grinding past one another. These different interactions are characterized by the three types of plate boundaries.

So far we've learned that there are three main types of plate boundaries. Visit the links below to complete your notes.

1. Divergent (plates moving apart)
2. Convergent (plates moving together)
3. Transform (plates slide past each other)

Once you have complete your notes, check out the plate tectonics map and try to find examples of each of the boundaries listed below. Mark these places on your copy of the plate boundary map.

• Divergent Boundary - oceanic
• Divergent Boundary - continental
• Convergent Boundary - oceanic/continental
• Convergent Boundary - oceanic/oceanic
• Convergent Boundary - continental/continental
• Transform Boundary - continental
  

When your finished, watch this video to review what you've just learned. Answer the questions below to prepare for your quiz.

1. What type of plate boundary is associated with mountain building?
   
2. How is new sea floor created?
3. Are earthquakes associated with every type of plate boundary?
   
4. How did the Cascade Mountain range form?
5. While continental crust is primarily made up of less-dense granite, the lava that flows from volcanoes is mostly more-dense basalt (thus you hear about 'basalt flows'). Explain how this is possible?