Name: ______

Regents Review #12: Geologic History

  1. Unconformities mean ______happened, so a layer is ______.
  2. ______can cause folding.

Use the above diagram to answer questions 3 - 6.

  1. Which came first, intrusion A or rock layer B? Give a reason. ______

______

  1. Which came first, rock unit C or the faulting? Give a reason. ______

______

  1. The wavy line at D is called an ______. Because it is there, we know ______happened.
  2. What happened to the rocks at letter E immediately after they were deposited? ______
  1. Where was NYS located during the Devonian period? ______
  2. When did oxygen first begin to form? ______
  3. The Earth is ______years old.
  4. You could find fossils of Malcurites near what city? (there are 2 possible answers) ______

______

  1. If we find fossils of corals in NYS, what does this tell us? ______

______

  1. Earth’s atmosphere was formed by ingassing/outgassing from Earth’s interior.
  2. Good index fossils are species that existed for a long/short time and are they are found in a widespread/small area.
  3. What else can also be a good time marker? ______
  1. Define half life: ______

16. Radioactive decay is/is not affected by the mass of the sample, temperature, or pressure.

  1. Carbon-14 can be used to date any remain that is
  2. ______
  3. ______

The above graph shows the decay of a radioactive isotope. Use it to answer 18 – 21.

  1. Which line represents the radioactive isotope? ______
  2. IF this graph was representing C14 (which it isn’t!) the other line would represent ______
  3. Approximately how long is the half-life for this substance? ______
  4. After how many days would 25% of the isotope be left? ______
  5. How do we know that this is NOT C14? ______
  6. About how long does it take for 75% of all the C14 in a sample to become N14? ______

Regents Review #12: Geologic History KEY

  1. weathering and erosion, missing
  2. Earthquakes
  3. B because it is affected by contact metamorphism.
  4. C because is affected by the faulting.
  5. Unconformity, weathering and erosion
  6. Tilting or folding.
  7. Near the equator
  8. During the Middle Archean Eon
  9. 4.6 billion
  10. Watertown or Oswego
  11. NYS was once covered by a warm shallow sea OR NYS was not always located at 40°N OR it must have been closer to the equator OR supports the theory of continental drift
  12. outgassing
  1. short, widespread
  2. Volcanic ash/meteorite deposits
  3. time it takes for HALF of the material to break down

16. is not

  1. Organic
  2. Less than 70,000 years old
  1. The one that is going down.
  2. N14
  3. 5 days
  4. 10 days
  5. The half life is only 5 days
  6. 11,400 years.