Across
- 2. all of time since the earth was created split up into different time intervals
- 7. the oldest layer of rock is on the bottom and the youngest is on top
- 9. a rock that is included from another layer of rock is in another rock layer, the included rock is older than that layer
- 10. the estimated age of a rock or organism
Down
- 1. the cut in rock layers is younger than the layers it occurred in
- 3. the remains of a once-living animal
- 4. a fossil found in a layer that is only found in that layer
- 5. decay the breaking down of a group of isotope
- 6. how long it takes for half of the parent isotopes to decay
- 8. finding the exact age of something based on radioactive decay