Across
- 3. unstable isotope of carbon (with 14 neutrons) found in fossils of living things
- 5. molten magma that penetrates into layers from below
- 8. any part of a previous rock layer, like a piece of stone, is older than the layer containing it
- 11. the process of putting events in the order in which they happened
- 14. an absolute dating method that dates trees by studying tree rings
- 15. a crack or break that occurs across rock layers
- 16. a law in relative dating that states the oldest layer is at the bottom and the youngest layer is on top
Down
- 1. any feature that cuts across rock layers is younger than the layers
- 2. a type of absolute dating that measures the presence of radioactive isotopes to determine age
- 4. a new flat surface with original material missing from erosion
- 6. the age of the earth is 4.6 ________ years old
- 7. any process that provides the real age of a sample in years
- 9. the isotope that carbon-14 decays into
- 10. the amount of time it takes half of the unstable atom to decay (measured in years)
- 12. an atom of the same element with a different number of neutrons
- 13. the preserved remains, or traces of remains, of ancient organisms