Choice Board Terms and Definitons

1234567891011121314
Across
  1. 3. the time required for half of a sample of a radioactive isotope to break down by radioactive decay to form a daughter isotope
  2. 7. 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
  3. 9. a long cylinder of ice obtained from drilling through ice caps or ice sheets; used to study past climates
  4. 10. any method of determining whether an object is older or younger than other events or objects
  5. 11. any method of measuring the age of an event or object in years
  6. 13. the trace or remain of an organism that lived long ago, most commonly preserved in sedimentary rock
  7. 14. the standard method used to divide the Earth's long natural history into manageable parts
Down
  1. 1. a principle that states that younger rocks lie above older rocks if the layers have not been disturbed
  2. 2. a fossilized structure, such as a footprint or a coprolite, that formed in sedimentary rock by animal activity on or within soft sediment
  3. 4. the average weather conditions in an area over a long period of time
  4. 5. an ordered arrangement of rock layers that is based on the relative ages of the rocks and in which the oldest rocks and in which the oldest rocks are at the bottom
  5. 6. a principle that geologic processes that occurred in the past can be explained by current geologic processes
  6. 7. the process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element
  7. 8. a break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period time
  8. 12. the scientific study of the origin, history, and structure of the Earth and the processes that shape Earth