Across
- 3. relating to material that comes from a volcano
- 5. fossil fuels consist of these
- 7. the largest of the two supercontinents that made up Pangaea
- 10. the remains and traces of prehistoric life
- 11. the fuel for fission nuclear reactions
- 13. Pangaea broke up and reptiles become dominant
- 15. this type of weathering changes a rock's composition
- 17. these make up 97% of the earth's water
- 18. the release of elastic energy in the earth
- 19. the lowest level at which a stream can erode
- 21. a thick mass of ice that forms above the snowline
Down
- 1. mountains will one day erode down to sea level
- 2. the period of time before the boom in life
- 4. a deposit of windblown silt that forms a landscape
- 6. the spontaneous decaying of nuclei
- 8. a large piece of pyroclastic material; can kill someone
- 9. "seismic sea wave"
- 12. the composition of this determines volcanoes
- 14. the many different ways that mountains are formed
- 16. holds 2/3 of the world's freshwater
- 20. having to do with earthquake waves