Review

1. Period of extensive ice sheet coverage
6. A former supercontinent
8. An undersea mountain chain where sea-floor spreading occurs
9. "Her Deepness" holds the record for the deepest walk on the seafloor
11. The climate of past geological eras, before direct instrumental records
13. Shaking of the ground caused by the sudden release of energy in the Earth's crust
14. A break in the Earth's crust where movement occurs
16. A boundary where plates slide past each other
18. where a continent and ocean meet, may be active or passive
19. Geologist who mapped the Mid-Atlantic Ridge, proving plate tectonics
21. The layer between the Earth's crust and core
23. The process where one plate is forced beneath another at a convergent boundary
24. Came up with the idea of continental drift
26. A deep valley on the ocean floor formed at a subduction zone
27. The Earth's outermost, thin layer

2. One of Earth's main, very large, continuous landmasses,
3. A boundary where plates move away from each other
4. The process of particles settling and accumulating on the seafloor
5. A valley that forms where two plates move apart
7. Cylinder of ocean or lake floor sediments that records past environmental changes.
10. The process where new oceanic crust is formed at a mid-ocean ridge and pushes older crust away
12. The largest ocean
15. Inventor of the Aqua-Lung, an early form of scuba diving
17. A boundary where two plates collide
20. The theory that the continents slowly move across the Earth's surface
22. Cylinder drilled from ice sheets, containing trapped air bubbles
25. A vent in the Earth's crust through which lava, gas, and ash erupt