Plate tectonics

2. what moves the crust
6. plates are moving towards one another.
7. occurs when two tectonic plates move away from each other.
10. a continues elevated zone on the floor of all the major ocean basins
12. of irregular topography on the deep ocean floor
13. what is the oceanic crust made of
14. made the hypothesis of the sea floor spreading
15. what does a convergent plates make
16. a narrow elongated depression of the sea floor
17. has a less density than oceanic crust
18. plates are moving up and down each other
19. mountains formed in part igneous activity associated with the subduction of oceanic lithosphere beneath a continent
20. two oceanic plates converge

1. elevated areas of the sea floor characterized by high heat flow and volcanism
3. a chain of volcanic islands generally located a few hundred km from trench
4. they are made by earthquakes
5. older,denser portions of oceanic lithosphere descends
8. the primary source of the movement of plates
9. a hypothesis, first proposed in the 1960s by harry hess
11. has a greater density than continental crust