Plate Tectonics

3. A layer of molten iron and nickel that surrounds the inner core of the Earth
7. that pieces of the Earth's lithosphere are in motion,driven by convection currents in the mantle
9. A deep valley where two plates move apart
12. The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary
14. A plate boundary where two plates grind against each other, moving it different directions
15. The undersea mountain mountain chain where new ocean floor is produced; a divergent plate boundary
16. Thickest layer of the Earth; it consists of two layers - the lithosphere and the asthenosphere
18. A soft layer of the mantle on which the lithosphere floats
19. A break or crack in the Earth's lithosphere along which rocks move
20. A plate boundary where two plates move toward each other

1. Alfred Wegener's hypothesis that the continents were once one huge land mass but have since then drifted apart
2. A deep canyon on the ocean floor
4. Cause the plates to move; between the lithosphere and the asthenosphere
5. A plate boundary where two plates move away from each other
6. The layer of rock that forms the Earth's outer surface
8. A rigid layer made up of the uppermost part of the mantle and the crust
10. Dense ball of solid material at the center of the Earth
11. The process by which molten material adds new oceanic crust to the ocean floor
13. German Scientist who developed the Theory of the Continental Drift in 1912.
17. The name of the single landmass that broke apart about 225 million years ago