Plate tectonics

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Across
  1. 3. elevated areas of the sea floor characterized by high heat flow and volcanism
  2. 6. what moves the crust
  3. 8. of irregular topography on the deep ocean floor
  4. 11. mountains formed in part igneous activity associated with the subduction of oceanic lithosphere beneath a continent
  5. 12. a chain of volcanic islands generally located a few hundred km from trench
  6. 15. older,denser portions of oceanic lithosphere descends
  7. 19. what is the oceanic crust made of
  8. 20. a hypothesis, first proposed in the 1960s by harry hess
Down
  1. 1. what does a convergent plates make
  2. 2. occurs when two tectonic plates move away from each other.
  3. 4. has a greater density than continental crust
  4. 5. plates are moving towards one another.
  5. 7. plates are moving up and down each other
  6. 9. a narrow elongated depression of the sea floor
  7. 10. two oceanic plates converge
  8. 13. the primary source of the movement of plates
  9. 14. a continues elevated zone on the floor of all the major ocean basins
  10. 16. has a less density than oceanic crust
  11. 17. made the hypothesis of the sea floor spreading
  12. 18. they are made by earthquakes