Across
- 2. the time taken for the radioactivity of a specified isotope to fall to half its original value
- 5. the process of determining if one rock or geologic event is older or younger than another, without knowing their specific ages
- 6. the action or process of forcing body of ingenious rock between or through existing formations, without reaching the surface
- 7. a fossil that is useful for dating and correlating the strata in which it is found
- 8. a fraction or zone of fractures between two blocks of rock
Down
- 1. energy released in the form of particle or electromagnetic waves
- 3. the "calendar" for events in Earth's history that subdivides all time into units
- 4. the remains or impression of a prehistoric organism preserved in petrified form or a mold or cast in rock