plate tectonics
Across
- 2. boundaries- What boundaries is where two plates slip past each other,moving past each other?
- 3. is any trace of any trace of an ancient organism that has been preserved in rock.
- 8. ocean ridge-When does sea floor spreading begin?
- 9. drift-Wegener's idea that continents slowly moved over Earth's surface became known as?
- 11. its when wegener made a what about the continents were once joined together in a single landmass and have since drifted apart?
- 12. supercontinent,or single landmass,about 300 million years ago.
- 13. thing did wegener infer lived on a single landmass
- 18. oceans- what ocean is expanding?
- 19. boundaries- what boundaries is two plates that move slowly away from each other?
- 20. floor spreading-what adds more crust to the ocean floor?
Down
- 1. boundaries-What boundaries is where two plates collide?
- 4. the process by which the ocean floor sinks beneath a deep ocean trench and back into a mantle is called?
- 5. was the name of the scientist?
- 6. these pieces became the what?
- 7. As the plates move what do they do?
- 10. did scientist mapped mid ocean ridges using?
- 14. floor- part of what sinks back into the mantle at deep ocean trench?
- 15. and shape-the processes of subduction and sea floor spreading can change what?
- 16. valley-where peices of Earth's crust diverge on land,a deep valley called a ?
- 17. ocean trench-At what trench does the oceanic crust bend downward?