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