Across
- 2. fossils: used for dating and comparing rock strata, based on previous organisms
- 5. the rate of decay of radioactive material, the time it takes for half of it
- 7. the current Eon, marked by the extinction of non-avian dinosaurs
- 9. the law that states that undisturbed rock material forms from oldest to youngest, with the oldest on the bottom and youngest on the top
Down
- 1. the first life on earth, single-celled microscopic organisms
- 2. the law that states that any rock that is included in the formation of another rock is older than that which it is being included in
- 3. the law that states that any rock material that cuts across another is younger in age than that which it crosses
- 4. age: the approximate time in which a rock has existed, compared to those around it
- 6. the Eon in which the first life was formed
- 8. age: the precise time in which a rock has existed, based on radioactive testing or fossils