Geological time

1234567891011121314151617181920212223
Across
  1. 4. What kind of relationships states that an intrusion or a fault is younger than the rock it cuts across.
  2. 10. A record of Earth's history from its origin 4.6 billions years ago to the present; A summary of major events in Earth's history that are preserved in the rock record. (two words)
  3. 12. the change in populations as a result of environmental change
  4. 13. fossils indirect evidence of plant and animal life (footprints, worm holes, etc.)
  5. 15. beds distinctive sediment layers, things like volcanic ash, sediments after asteroid impacts and lava flows are all markers that geologist use to separate time
  6. 17. preservation The soft and hard parts of plant and animal remains that have not undergone any kind of change since the organisms' deaths.
  7. 18. formed when the original shell parts of an organism within a sedimentary rock are weathered or eroded
  8. 21. is a gap in a rock record caused by erosion and weathering
  9. 22. horizontality States that sedimentary rocks are deposited in horizontal or nearly horizontal layers
  10. 23. the evidence or remains of once-living plants or animals
Down
  1. 1. what principle states that overlying rock layers can contain loose materials from the rocks below them
  2. 2. dating process used to determine the absolute age of a rock or fossil by determining the ratio of parent nuclei to daughter nuclei within a given sample
  3. 3. decay the emission of radioactive particles at a constant rate from a radioactive substance and its resulting change into other elements over time
  4. 5. is the matching of outcrops of one geologic region to another
  5. 6. period of time it takes for a radioactive isotope, such as carbon-14, to decay to one-half of its original amount
  6. 7. formed when the cavity inside of the original shell is filled with minerals or sediments that harden
  7. 8. hard parts form when all the organic material has been removed and the hard parts of a plant or animal have been changed by mineral replacement or recrystallization
  8. 9. the process by which pore spaces are filled in with mineral substances
  9. 11. the third longest unit of geologic time, measured in millions of years
  10. 12. the second longest unit of geologic time, measured in hundreds of millions and billions of years
  11. 14. the longest unit of geologic time, measured in billions of years
  12. 16. smallest units of geologic time, measured in millions and hundreds of thousands of years
  13. 19. what law says that the rocks on the bottom of a rock record are the oldest (law of _________)
  14. 20. fossils the remains of plants and animals that can be used for geologists to correlate rock layers over large geographic areas or to date a particular rock layer