Across
- 3. breaking down of unstable radioactive isotopes into other stable isotopes
- 6. how sedimentary rock is formed
- 8. the radioactive isotope before it decays
- 11. determining the actual age of an event or object in years
- 12. widespread lived for a short period abundant
- 13. include tracks, burrows, and even animal dung called coprolite
- 14. finding the absolute age by determining the relative percentages of radioactive parent and stable daughter isotopes
Down
- 1. the stable isotope after it decays
- 2. type of rock where fossils are formed
- 4. geologic process what happened in the past can be explained by the current processes
- 5. states that younger rock layers lie about the older rock layers if they layers have not been distrubed
- 7. determining whether an object or event is older or younger than other objects or events
- 9. traces or remains of organisms that lived long ago
- 10. time needed for half of a radioactive element to undergo decay