1. Geologic Time Notes Page 3
©Mark Place,

2. Fossils can only be found in rocks.
sedimentary

3. On to the next question...

4. never lived at the same time
Why is this statement false: “The caveman had dinosaur for breakfast.”?
man and dinosaurs
never lived at the same time

5. Answers to Questions on Page 3
On to page 4....

6. Relative Age
If a sedimentary rock outcrop has not been overturned, which layer would be the oldest? What is this principle known as?

7. oldest rock layers are on bottom Principle of Superposition

8. Using this principle, label the strata below from oldest to youngest.

9. On to the next question...

10. Faults are always (older, younger) than the rocks they cut through.

12. there first (it's older)
Which is older:
F or S
How do you know?
F cuts through S
S must have been
there first (it's older)

13. On to the next question...

14. If a geologist finds an igneous sill, how can she determine if the sill is an intrusion or an extrusion?

16. contact metamorphism on all sides
Intrusions
contact metamorphism on all sides

17. no contact metamorphism on top
extrusions
no contact metamorphism on top

18. Is “H” an intrusion or extrusion? How can you tell?

19. H is an intrusion. Contact metamorphism on top

20. On to the next question...

21. a buried erosional surface
What is an unconformity?
a buried erosional surface
How does it complicate the relative dating of rock layers?
a part of the rock record
is missing

22. weathering and erosion
What processes could lead to an unconformity?
weathering and erosion

23. Using the diagram to the left, identify where the unconformity is located by drawing an arrow and writing the word “unconformity” next to it.

24. On to the next question...

25. What characteristics must fossils have in order to be good index fossils?
lived over a large geographic area (large horizontal distribution)
lived for a short period of time (small vertical distribution)

26. In geology, this is referred to as CORRELATION
In the diagram below, a geologist has matched up rock layers based on index fossils.

27. On to the next question...

28. Evolution organisms adapt to their environment in order to survive
Explain the theory of evolution.
organisms adapt to their environment
in order to survive

29. Evolution can see that different organisms have changed over time
Explain how the fossil record supports this theory
can see that different organisms have
changed over time

31. Answers to Questions on Page 31
Approximately how many million years ago did the earliest amphibians appear? 2
Approximately how many million years ago was the initial opening of the Atlantic Ocean? 3
During which era did the earliest fish appear?
Paleozoic 4
During which epoch did large carnivores appear?
Pliocene 5
Of the following rocks which would be most likely to contain fossils?
a. rhyolite b. basalt c. metaconglomerate d. limestone
limestone (it’s sedimentary) 6
At Binghamton, NY what is age of the bedrock?
Devonian ( million years) 7
How does the age of the bedrock at Old Forge compare with that at Jamestown?
Jamestown is younger 8
Name a location in NY State where you may be able to find bedrock which was formed at the peak of the eurypterid’s development.
Silurian age bedrock: Niagara Falls, Syracuse 9
Why would fossils be unlikely to be found in quartzite?
it’s metamorphic 10
For each of the following locations in NY State below, identify whether fossils would be likely or unlikely: Old Forge; Binghamton; Albany
Old Forge: unlikely
Binghamton: likely
Albany: likely

32. their half-lives are constant
Absolute Age
Why are radioactive isotopes useful in
determining the absolute age of a rock?
their half-lives are constant

33. NOTHING! it is reliable to calculate age
Absolute Age
What can be done to change the
half-life of a radioactive isotope?
Why is this important?
NOTHING!
it is reliable to calculate age

34. stable atoms unstable atoms Draw the generic graph for the
half-life of a radioactive isotope.
stable atoms
unstable atoms

35. carbon-14 What radioactive isotope could be
Absolute Age
What radioactive isotope could be
used to determine the absolute
age of material that was recently living?
carbon-14

36. What is the half life of uranium-238?
Please answer the two questions
on page 7 of your Notes
What is the half life of uranium-238?
4.5 x 109
4,500,000,000
4.5 billion years
choice (c)

37. 3 half-lives x (5.7 x 103) =1.71 x 104 = 17,100 years
Please answer the two questions
on page 7 of your Notes
If there is a 100g sample of C14, how many grams of
C14 would remain after three half-lives?
How long would this take? Show all work.
100g 
50g 
25g 
12.5g
3 half-lives x (5.7 x 103) =1.71 x 104
= 17,100 years