Earthguide Online Classroom

Supercontinents and the Wilson Cycle


  1. Observe and explain the two main processes of plate tectonics - 1) seafloor spreading and 2) subduction
  2. Identify topographic features that are associated with 1) seafloor spreading and 2) subduction
  3. Determine the number of plates shown on this diagram
  4. Introduce vocabulary
  5. Distinguish between lithosphere and crust
  6. Discuss how this map was produced.
  7. Speculate on the origin of significant features
  8. How many plates are shown?

Questions for thought

  1. Does the arrangement of continental and oceanc crust on this diagram
  2. Which of the two major oceans shown on tnis diagram are growing new seafloor?
  3. Are both of the oceans on this diagram growing in area?
  4. Is anything happening to the area of continental crust?
  5. How can both oceans be growing new seafloor and yet one ocean is getting smaller?
  6. If the Pacific continues to shrink? What will happen?

Questions for the future (i.e. people don't know at all or they are not sure)

  1. Why is there no subduction where oceanic crust meets continental crust around the Atlantic?


  1. We've made continents that don't change overall size. While it's not entirely true, the overall areas of the continents has changed very little since the cores of the continents formed in the distance past, when compared to oceans that change size by growing and disappearing on a regular basis.
© 2007 Earthguide at Scripps Institution of Oceanography.
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