Across
- 6. age of rock given in exact years
- 7. age of rock not given exactly
- 9. any feature that cuts across a sequence of rocks, is younger than everything it cuts.
- 10. time it takes for half of a remaining form to decay to a daughter product
Down
- 1. first life form believed to be on Earth
- 2. an undisturbed sequence of rocks, the oldest rocks are on the bottom and the youngest on the top.
- 3. any rock or fragment that’s included inside of another rock is older than the rock in which it is included.
- 4. unstable isotope o some element decay at a known rate into daughter products
- 5. useful for dating and correlating the strata it is found in
- 8. remains of organisms