Across
- 5. The undersea mountain chain where the new ocean floor is produced; a divergent plate boundary
- 8. A plate boundary where two plates move away from each other
- 10. The process by which molten material adds new oceanic crust to the ocean floor
- 11. A weak spot in the crust where magma has come to the surface
- 13. The molten mixture of rock-forming substances, gases, and water from the mantle
- 14. An area where magma from deep within the mantle melts through the crust above it
- 17. Cause the plates to move; between the lithosphere and the asthenosphere
- 18. A layer of molten iron and nickel that surrounds the inner core of the Earth
- 19. A plate boundary where two plates move toward each other
Down
- 1. Alfred Wegener's hypothesis that the continents were once one huge landmass
- 2. Theory that pieces of the Earth's lithosphere are in motion,driven by convection currents in the mantle
- 3. Liquid magma that reaches the surface
- 4. The theory that Earth's outer shell is divided into several plates that glide over the mantle.
- 6. Dense ball of solid material at the center of the Earth
- 7. The layer of rock that forms the Earth's outer surface
- 9. The name of the single landmass that broke apart about 225 million years ago
- 12. a crater formed by a collapsed volcano
- 15. Thickest layer of the Earth; it consists of two layers the lithosphere and the asthenosphere
- 16. A major belt of volcanoes that rims the pacific ocean