Science Vocab Definitions - Fossils

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Across
  1. 2. A break in the geological record created when rock layers are eroded or when sediment is not deposited for a long period of time
  2. 3. A fossilized structure that formed in sedimentary rock by animal activity
  3. 4. The process in which radioactive isotopes tends to break down into a stable isotope of the same element or another element
  4. 5. Any method of measuring the age of an event or object in years
  5. 7. A long cylinder of ice obtained by drilling through ice caps used to study past climates
  6. 8. The scientific study of origin, history, and the structure of earth and the processes that shape earth
  7. 10. The trace remains of an organism usually preserved in sedimentary rock
  8. 11. The weather conditions over a long period of time
  9. 12. Any method of determining whether an event or object is older or younger than other events or objects
  10. 14. The standard method used to divide earth's long natural history into manageable parts
  11. 15. An ordered arrangement of rock layers that is based on the relative ages of the rocks in which the oldest rocks are at the bottom
Down
  1. 1. A method of determining the absolute age of an object by comparing the relative percentages of a radioactive (parent) isotope and a stable (daughter) isotope
  2. 6. Geological processes in past are explained by current geological processes
  3. 9. A principle that states younger rocks lie above older rocks if the layers have not been distributed
  4. 13. The time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope