Plate Tectonics

2. a deep canyon on the ocean floor
5. name of the single landmass that broke apart about 225 million years ago
7. valley, a deep valley where two plates move apart
9. a rigid layer made up of the uppermost part of the mantle and the crust
13. drift, Alfred Wegener's hypothesis that the continents were once one huge land mass but have since then drifted apart
14. currents, cause the plates to move between the lithosphere and the asthenosphere

1. Wegener, German Scientist who developed the Theory of the Continental Drift in 1912
3. boundary, a plate boundary where two plates move toward each other
4. thickest layer of the Earth, consists of two layers-the lithosphere and the asthenosphere
6. the layer of rock that forms the Earth's outer surface
8. boundary, a plate boundary where two plates move away from each other
10. a soft layer of the mantle on which the lithosphere floats
11. core, dense ball of solid material at the center of the Earth
12. a break or crack in the Earth's lithosphere along which rocks move
15. core, layer of molten iron and nickel that surround the inner core of the Earth