Geologic Time Crossword

Edit Answers
1234567891011121314151617
Across
  1. 1. The amouunt of time it takes for half of a radioactive element to decay into a stable isotope
  2. 5. Type of dating that does NOT provide an exact date
  3. 7. Type of isotope that is radioactive and therefore unstable
  4. 9. Type of isotope that is stable and comes from the decay of radioactive isotopes
  5. 10. Theory which states the present is key to the past
  6. 12. Refered to as an unconformity by scientists we typically see this represented by a squiggly line
  7. 14. The Earth is 4.6 _________ years old
  8. 15. Magma that pushes through rock layers
  9. 17. Law that states sedimentary rock layers are laid down horizontally
Down
  1. 2. Type of dating that provides an EXACT date
  2. 3. Break in a rock with movement
  3. 4. Greatest unit of geologic time
  4. 6. Theory which states the Earth was formed by catestrophic events.
  5. 8. Law that states the location of older rocks on the bottom and younger rocks on top
  6. 11. Type of rock almost all fossils are found in
  7. 13. The remains or impressions of prehistoric organisms preserved in rock
  8. 16. Smallest unit of geologic time