geologic time scale

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Across
  1. 2. any rock or fragment that is included inside of another rock is older than the rock in which it is included
  2. 6. using radioactivity to find an exact age
  3. 8. any feature that cuts across a sequence of rocks, is younger than everything it cuts
  4. 9. a fossil used to find ages of other fossils
  5. 11. the current era
Down
  1. 1. closest to top is youngest closest to bottom is oldest
  2. 3. using the law of superposition to find a age
  3. 4. before mesozoic,after precambrian.
  4. 5. the amount of time it takes for half a remaining isotope to decay to a daughter product
  5. 7. age of the dinos
  6. 10. rock layers