Across
- 1. zone/The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary
- 4. layer of the Earth; it consists of two layers - the lithosphere and the asthenosphere
- 8. boundary/A plate boundary where two plates move toward each other
- 9. Wegener/The layer of rock that forms the Earth's outer surface
- 10. Drift/Alfred Wegener's hypothesis that the continents were once one huge land mass but have since then drifted apart
- 13. ridge/The undersea mountain mountain chain where new ocean floor is produced; a divergent plate boundary
- 14. soft layer of the mantle on which the lithosphere floats
- 16. spreading/The process by which molten material adds new oceanic crust to the ocean floor
- 17. break or crack in the Earth's lithosphere along which rocks move
- 18. of Plate Tectonics/Theory that pieces of the Earth's lithosphere are in motion,driven by convection currents in the mantle
- 20. core/A layer of molten iron and nickel that surrounds the inner core of the Earth
Down
- 2. boundary/A plate boundary where two plates move away from each other
- 3. /The name of the single landmass that broke apart about 225 million years ago
- 5. boundary/A plate boundary where two plates grind against each other, moving it different directions
- 6. currents/Cause the plates to move; between the lithosphere and the asthenosphere
- 7. core/Dense ball of solid material at the center of the Earth
- 11. deep canyon on the ocean floor
- 12. rigid layer made up of the uppermost part of the mantle and the crust
- 15. valley/A deep valley where two plates move apart
- 19. layer of rock that forms the Earth's outer surface