Across
- 3. definite; age in years
- 5. hard material; 3 kinds; formed variously
- 7. young or old compared to other rock
- 9. unstable; relating to ionizing
- 10. any rocks in rock layer are older
Down
- 1. law that says deeper rocks are older
- 2. large period of time
- 4. anything cutting through layer-youngest
- 6. help determine absolute age of rocks
- 8. amount of time taken for isotope to decay