Name: _________________________
1. Unconformities mean ________________ happened, so a layer is ___________.
2. ____________________ can cause folding.
D
B
A
C
E
Use the above diagram to answer questions 3 - 6.
3. Which came first, intrusion A or rock layer B? Give a reason. _____________________
_______________________________________________________________________
4. Which came first, rock unit C or the faulting? Give a reason. ______________________
_______________________________________________________________________
5. The wavy line at D is called an ______________________. Because it is there, we know
_______________________________________________ happened.
6. What happened to the rocks at letter E immediately after they were deposited?
_______________________________________________________________________
7. Where was NYS located during the Devonian period? ____________________________
8. When did oxygen first begin to form? _________________________________________
9. The Earth is ________________________ years old.
10. You could find fossils of Malcurites near what city? (there are 2 possible answers) _________
______________________________________________________________________

11. If we find fossils of corals in NYS, what does this tell us? _________________________
______________________________________________________________________
12.
Earth’s atmosphere was formed by ingassing/outgassing from Earth’s interior.
13. Good index fossils are species that existed for a long/short time and are they are found in a widespread/small area.
14. What else can also be a good time marker? ____________________________________
15. Define half life: __________________________________________________________
16. Radioactive decay is/is not affected by the mass of the sample, temperature, or pressure.
17. Carbon-14 can be used to date any remain that is a. _________________________________________________________________ b. _________________________________________________________________
The above graph shows the decay of a radioactive isotope. Use it to answer 18
– 21.
18. Which line represents the radioactive isotope? _________________________________
19. IF this graph was representing C 14 ( which it isn’t!
) the other line would represent _________
20. Approximately how long is the half-life for this substance? ________________________
21. After how many days would 25% of the isotope be left? __________________________
22. How do we know that this is NOT C 14 ? _______________________________________
23. About how long does it take for 75% of all the C 14 in a sample to become N 14 ? ________

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
13. short, widespread
14. Volcanic ash/meteorite deposits
15. time it takes for HALF of the material to break down
16. is not
17. a. Organic b. Less than 70,000 years old
18. The one that is going down.
19. N 14
20. 5 days
21. 10 days
22. The half life is only 5 days
23. 11,400 years.