Geologic Time Scale

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Across
  1. 2. When scientists want to find a time period they use this form of dating
  2. 3. In the sequence of sedimentary rock the newer rock layers will be on top of older ones
  3. 4. Geologists use Index fossils to determine the the ago of rock what
  4. 7. Era that the first form of life showed up
  5. 10. What era did the dinosaurs show up
  6. 11. A what that shows the geologic eons and divides the history of the earth of earth based on events and changes to earth
  7. 12. The amount of time it takes for a half of a remaining isotope to decay a daughter product
Down
  1. 1. Two methods are used for determining the age of rocks and fossils
  2. 5. When scientists want an age in actual years they use this form of dating
  3. 6. When the same fossils are found in all of the same layers
  4. 8. Carbon 14 dating dates a living organism by the amount of what in the cellular structure
  5. 9. Age dating can be based off of this