Planet Earth

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Across
  1. 5. Time it takes 1/2 of the atoms to decay into an isotope
  2. 7. Formed at a convergent boundary
  3. 10. In a cross-section of rock, oldest at the bottom
  4. 14. Approximate age
  5. 15. Large landmass consisting of all the continents
  6. 16. State of matter of the inner core
  7. 17. ridge Example of a divergent boundary
Down
  1. 1. Plates slide in opposite directions
  2. 2. One type of crust
  3. 3. Crust and upper portion of mantle
  4. 4. Cools to form new crust
  5. 6. Broadest category in geologic time scale
  6. 8. Actual date that object died
  7. 9. Full spreading rate
  8. 11. Third planet from the sun
  9. 12. Tool used to represent carbon-14
  10. 13. Layer of rock