Across
- 3. geological processes explained by geological processes
- 5. trace remains of organisms in rocks
- 7. determine the absolute age of an object
- 9. weather conditions over a period of time
- 10. divide Earth´s history
- 12. a break in geologic record
- 13. ordered arrangement of rock layers
- 15. time required for radioactive isotope to break down
Down
- 1. radioactive isotope
- 2. younger rocks lay above older rocks
- 4. whether a object is older or younger than other objects
- 6. measuring the age of an event or object in years
- 8. fossilized structure in sedimentary rock
- 11. study of history and structure of Earth
- 14. long cylinder of ice