Choice board!

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Across
  1. 3. core A long cylinder of ice obtained from drilling through ice caps or ice sheets; used to study past climates
  2. 4. time scale The standard method of used to divide earth’s long natural history into manageable parts.
  3. 6. decay A method of determining the absolute age of an object by comparing the relative percentages of a radioactive isotope and a stable isotope
  4. 8. The scientific study of the origin, history, and structure of earth and processes the shape earth
  5. 10. The trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock
  6. 11. A principle that geologic processes that occurred in the past can be explained by current geologic processes
  7. 12. column An ordered arrangement of rock layers that is based on the relative ages of the rocks and in which the oldest rocks are on the bottom
  8. 14. Fossil A fossilized structure, such as a footprint or a coprolite, that formed in sedimentary rock by animal activity on or within soft sediment
  9. 15. The weather conditions in an area over a long period of time
Down
  1. 1. A break in the geologic record created when sediment is not deposited for a long period of time
  2. 2. Dating Any method of determining whether an event or object is older or younger than other events or objects
  3. 5. decay The process in which a radioactive isotope tends to break down into stable isotope of the same element or another element
  4. 7. Dating Any Method of measuring the age of an event or object in years
  5. 9. A principle that states that younger rocks above older rocks if the layers have not been disturbed
  6. 13. life The time required for half of a sample of radioactive isotope to break down by radioactive decay to form a daughter isotope