Continental drift

4. is the original landmass that broke apart 225 million years ago
6. A plate boundary where two plates move away from each other
8. Theory that pieces of the Earth's lithosphere are in motion
11. Alfred Wegener's hypothesis that the continents were once one huge land mass
13. Dense ball of solid material at the center of he Earth
14. Cause the plates to move; between the lithosphere and the asthenosphere
17. A soft layer of the mantle on which the lithosphere floats
18. A plate boundary where two plates grind against each other, moving it different directions
19. A rigid layer made up of the uppermost part of the mantle and the crust

1. The undersea mountain mountain chain where new ocean floor is produced
2. The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary
3. A plate boundary where two plates move toward each other
5. A break or crack in the Earth's lithosphere along which rocks move
7. German Scientist who developed the Theory of the Continental Drift in 1912.
9. The layer of rock that forms the Earth's outer surface
10. The process by which molten material adds new oceanic crust to the ocean floor
12. A deep canyon on the ocean floor
15. A layer of molten iron and nickel that surrounds the inner core
16. Thickest layer of the Earth
20. A deep valley where two plates move apart