Across
- 3. Diagrams that show rock formations of a location or region.
- 6. Time required for half of the radioactive atoms present to decay.
- 7. Elements that emit ionizing radiation.
- 9. A method of dating geological or archeological specimens by determining the relative proportions of particular radioactive isotopes present in a sample.
- 10. Atoms of the same element that have different numbers of neutrons.
Down
- 1. The principle that the present is the key to the past.
- 2. Are used to determine the age of the rocks they were preserved in.
- 4. The age of rocks in relation to the rocks around them
- 5. The process by which unstable atomic nuclei lose energy through radiation.
- 8. The numeric age of rocks and fossils.