Plate Tectonics

2. the temperature of older crust is ______ than newer crust.
5. when the mid-ocean ridge adds more sea floor.
7. new crust is ____ ______ than old crust.
8. a system for the detection of objects under water and for measuring the water's depth by radiating waves is called a?
9. older crust is ____ _____ than newer crust.
10. pieces separated by cracks.
14. when plates move away from each other.
15. when the ocean floor goes into a canyon, what are the canyons called?
16. peices of Earth’s crust diverge on land.
18. the name of the most popular supercontinent.
19. When continents moved slowly over Earth's surface is called?

1. the remains of a historic thing molded in a form or as a mold in rock?
3. a scientist who discovered pangea
4. when plates slide on top or past each other.
6. Where the ocean spreads.
8. the sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate is called what?
11. when plates come together.
12. the temperature of newer crust is _____ than older crust.
13. plates movement into a theory.
17. a break in the Earth's crust where sediment (rock and other things) have slipped past each other.