Earths History Vocabulary

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Across
  1. 3. Age Determination of the age based on the surrounding evidence
  2. 4. Subdivision of a period; shortest division of geologic time
  3. 7. Fossil A common fossil found in many areas from a specific time; used to help identify the age of other formations
  4. 9. Subdivision of an eon (paleozoic, mesozoic, cenozoic)
  5. 10. Fossil that forms when organic material is pressed between layers of rock
  6. 11. Fossil that forms when a mold is filled with sediment and hardens into the shape of that organism
  7. 15. Dating Method of determining the age based on measuring radioactive elements (radiometric) .
  8. 16. Very large division of geologic time; usally refereed to as the longest division of time.
  9. 17. States that younger rock is found above older rock when comparing undisturbed sedimentary rock layers.
Down
  1. 1. The system of time measurement involving the formation of and changes to earth
  2. 2. Subdivision of an era
  3. 4. Occurs when a species (organism) dies out and no longer lives on the planet
  4. 5. A fossilized piece of evidence of an organisms activity (such as a footprint)
  5. 6. Fossil that forms when minerals solidify into rock around the shape of the orginal organism, leaving a cavity behind
  6. 8. Remains or impression of an organism preserved in petrified rock.
  7. 12. Record Refers to the information provided by all of the discovered fossils throughout the geologic history
  8. 13. The branch of science involving the physical composition and history of earth
  9. 14. Fossil that forms when organic material is trapped in ice, rock, amber or tar