Test 3/26/14
Geology and Paleontology Study Guide
Name:______________
1. 50 nanograms of carbon-14 are found in an ivory carving. It is estimated that there initially was 200
nanograms. How old is the carving? (Carbon-14 has a half-life of about 5,700 years)
50/200 = 25% Answer
would be 11,400
2. In a lab, paleontologists measure 1,200 carbon-14 atoms in an ancient scroll. They estimate that there
were originally 2,000 carbon-14 atoms. Approximately how old would they date the scroll to be?
1200/2000=60% Answer would be approximately 4,000 years
3. If a fossil still contains 25% carbon-14, how old would a paleontologist date that fossil to be?
Answer would be
11,400 years
4. A fossil has been determined to contain about 8% carbon-14. How old might a paleontologist date it to
be? Answer would be approximately 19,000 years
5. Which of the following is the correct age of the rocks (From oldest to youngest)?
C,G,E,D,B,A,F
6. Layer G is igneous rock that once flowed as magma. What term is used to describe this formation?
Intrusion
Test 3/26/14
Geology and Paleontology Study Guide
Name:______________
7. A cast is an object created when sediment fills a mold and becomes rock.
8. The fossils of organisms that were widely distributed but only lived during a short period of time are
called index fossils_
9. The time it takes for half of the radioactive atoms in a sample of a radioactive element to decay is
its_half-life_.
10. The law of _superposition_ states that, in horizontal layers of sedimentary rock, younger layers form
on top of older layers.
11. Radioactive dating works best with what type of rocks? Igneous rock
12. Determining whether an object or event is older or younger than other objects or events is called
relative dating.
13. Rock layers 4–6 in have been disturbed by _folding_
14. Which rock layer shown above would be the youngest?
Rock layer 6 would be the youngest
15. Which process disturbed these rock layers?
Faulting is what disturbed these rock layers.
16. Which rock layers have the same relative age?
Several possible answers could include 3-10, 2-9, or 1-8 because all have similar fossils found in them.
17. The principle of uniformitarianism states that the same geologic processes shaping the Earth today
have been at work throughout Earth's history.
18. A place where an old eroded surface is in contact with a newer rock layer is called an unconformity.
19. A fossil formed when minerals replace all or part of an organism is called a permineralized fossil
20. Determining the absolute age of a sample based on the ratio of parent material to daughter material is
called radiometric dating.