Geology 12
Geologic Time & The Fossil Record
Structural Geology
Provincial Exam Questions
EXTRA PRACTICE TEST #4
KEY
Geology 12 Test #4 - Extra Practice
ANSWER KEY
Geologic Time & The Fossil Record
Refer to your yellow data booklet for tables and charts.
Multiple Choice Answers:
1. B 2. B 3. C 4. D 5. B 6. C 7. A 8. C 9. D 10. D
11. C 12. D 13. D 14. C 15. C 16. B 17. D 18. A 19. B 20. C
21. D 22. D 23. D 24. C 25. B 26. B 27. B 28. B 29. B 30. C
31. D 32. D 33. A 34. B 35. A 36. C 37. C 38. A 39. C
Written Response answers follow the questions.
Use the following diagram of two cliff sections to answer questions 1 and 2.
A
G
KEY
INDEX
FOSSIL
B
H
C
D
I
E
J
F
K
1. Which pair of sedimentary rock layers in the cliff sections correlate with each other?
A.
B.
C.
D.
B and I
F and K
E and H
A and K
2. Which of the following is the most likely position of an unconformity?
A.
B.
C.
D.
between units A and B
between units G and H
between units A and G
between units C and E
Use the following graph to answer questions 3 and 4.
Decay of a radioactive isotope
100
Percent parent isotope remaining
90
80
70
60
50
40
30
20
10
0
0
50
100
150
200
250
Age (millions of years)
3. What is the half-life of the radioactive isotope shown in the graph above?
A. 50 m.y.
B. 55 m.y.
C. 60 m.y.
D. 125 m.y.
4. A sample is found to have only 40% of the original parent isotope remaining. What is the best
estimate of the age of the sample?
A.
B.
C.
D.
40 m.y.
45 m.y.
65 m.y.
80 m.y.
REFERENCE
DATA BOOKLET
For questions 5 and 6, refer to the following in the Data Booklet.
Geological Time Scale
Fossil Samples
Development of Life Through Time
5. Which of the following lists has the events in the correct order?
A.
B.
C.
D.
youngest
youngest
youngest
youngest
start of the
Mesozoic era
mammals dominated
formation of
coal forests
fishes dominated
appearance of
flowering plants
fishes dominated
first land plants
reptiles dominated
Pleistocene
glaciation
start of
Paleozoic era
appearance
of humans
mammals dominated
Precambrian rocks
earliest recorded life
Precambrian rocks
earliest recorded life
oldest
oldest
oldest
oldest
6. Which of the following is the best estimate of the age of the fossil shown below?
Silurian - 441mya to 418 mya
A.
B.
C.
D.
younger than 418 m.y.
older than 441 m.y.
between 418 m.y. and 441 m.y.
between 425 m.y. and 480 m.y.
7. In which of the following environments is an organism most likelyto be preserved as a fossil?
A.
B.
C.
D.
Which of the following is an example of a trace fossil?
A.
B.
C.
D.
A.
B.
Rate of evolution
Which graph best represents the rate of evolution as described by the concept of punctuated
equilibrium?
Rate of evolution
Time
Time
C.
D.
Time
Rate of evolution
9.
petrified wood
silicified ammonite shell
preserved worm burrows
permineralized dinosaur tooth
Rate of evolution
8.
sea floor
forest floor
coastal beach
toe of an active glacier
Time
10. Which of the following can best determine the absolute age of an igneous rock layer?
A.
B.
C.
D.
intrusions into the rock
fossils included in the rock
its position in a sequence of rock layers
radioactive decay of isotopes in the rock
Reference
Data Pages in
the Appendix
For question 11, refer to the geologic column below,
and to the following references in the Appendix.
Geological Time Scale
Fossil Samples
I
II
Mississippian
III
IV
11. Where does an unconformity definitely exist?
A.
B.
C.
D.
I
II
III
IV
12. Which of the following graphs shows the radioactive decay of an element with a half-life of
1 million years?
A.
B.
100
%
parent
material
100
%
parent
material
1
0
Time (million years)
C.
1
0
Time (million years)
D.
100
100
%
parent
material
%
parent
material
0
1
Time (million years)
2
0
1
2
3
Time (million years)
4
Use the following diagram of a geologic cross section to answer question 13.
Paleocene bone
ª 60 m.y.
Sandstone
Vesicles
Lava flow
ª 180 m.y.
5m
Mafic dike
100 m.y.
13. What is the most accurate age range for the sandstone layer?
A.
B.
C.
D.
less than 60 million years
60–100 million years
60–180 million years
100–180 million years
Reference
Data Pages in
the Appendix
For question 14, refer to the following reference in the Appendix.
Development of Life Through Time
14. Which of the following events in Earth’s history is out of order?
Youngest
A.
first humans
Rocky Mountains form
B.
reptiles dominate
amphibians dominate
C.
invertebrates dominate
fish dominate
D.
Precambrian era
Oldest
Use the following list of characteristics of organisms to answer question 15.
Characteristic
I
large numbers
II
lived on land
III
moved freely
IV
hard parts
V
lived in a marine environment
VI
remained stationary
15. Which combination of characteristics would give a species the best chance of leaving a fossil?
A. I, II and III
B. II, IV and VI
C. I, IV and V
D. II, III and IV
Photo courtesy of JAM Visuals
Use the photograph below of mammal footprints from the
Tertiary to answer questions 16 and 17.
1m
16. What name is given to the type of fossils shown in the photograph?
A.
B.
C.
D.
xenolith
trace fossil
brachiopod
original material
17. What was the most likely method of preservation of the fossils shown above?
A.
B.
C.
D.
replacement
carbonization
permineralization
mold and cast formation
For questions 18 and 19, refer to the cross-sectional diagram below
and to the following references in the Appendix.
Geological Time Scale
Fossil Samples
Reference
Data Pages in
the Appendix
Each rock layer represents a different geological period.
Layer I
Layer II
Layer III
Layer IV
5m
18. Which of the following would be the most likely fossil found in layer II?
A.
B.
C.
D.
19. The organisms that left the fossils in layers I and III lived in a similar environment.
In which of the following environments did they live?
A.
B.
C.
D.
forest
ocean
desert
mountain
20. Which of the following graphs best illustrates the concept of punctuated equilibrium of
organisms U, V and W evolving from an original species T?
A.
B.
U
Present
V
W
T
Past
U
Present
V
T
Past
Change in form
W
Change in form
D.
C.
W
Present
Present
W
V
V
U
U
Past
T
Change in form
Past
T
Change in form
21. Which of the following is not evidence for lithospheric plate motion?
A.
B.
C.
D.
jigsaw fit of the continents
coal deposits in Antarctica
matching rock structures in Africa and South America
striations on granite bedrock in southern British Columbia
22. At which type of plate boundary will deep focus earthquakes definitely occur?
A.
B.
C.
D.
rifting
divergent
transform
subduction
Reference
Data Pages
For questions 23 and 24, refer to the cross section below of a portion of the
Earth’s crust, and to the following references in the Data Pages.
Fossil Samples
Geological Time Scale
5
4
6
3
2
1
Diagram not drawn to scale.
Siltstone
Shale
Limestone
Igneous rock
Conglomerate
Contact
metamorphism
Sandstone
23. Which of the following is the correct sequence of events (from oldest to youngest) in the
geologic history of this area?
A.
B.
C.
D.
deposition of layers from 6 to 1, intrusion of igneous rock, faulting
deposition of layers from 1 to 6, intrusion of igneous rock, faulting
deposition of layers from 6 to 1, faulting, intrusion of igneous rock
deposition of layers from 1 to 6, faulting, intrusion of igneous rock
24. Which of the following is the most likely age of layer 2?
A.
B.
C.
D.
380 million years
400 million years
420 million years (Silurian)
460 million years
Use the following diagram to answer question 25.
The diagram represents the present number of radioactive parent and stable daughter atoms
in a mineral sample. The mineral sample was originally 100% radioactive.
radioactive parent atom
stable daughter atom
25. The half-life of the radioactive parent is 1 000 000 years.
Which of the following is the age of the mineral represented by the diagram?
A.
B.
C.
D.
1 000 000 years
2 000 000 years (8/32 = 25% = 2HL)
3 000 000 years
4 000 000 years
Use the following table to answer questions 26 to 29.
A geologist made the table after studying the fossils found in five beds of sedimentary rock.
youngest
Bed 5
Bed 4
Bed 3
Bed 2
Bed 1
oldest
Organism
lifestyle
attached
crawler
attached
burrower
floater
crawler
swimmer
Fossil
symmetry
radial
bilateral
bilateral
across
shells
bilateral
between
shells
none
none
bilateral
26. What is the name of the fossil shown below?
A.
B.
C.
D.
trilobite (arthropoda)
brachiopod (brachiopoda)
sea urchin (echinodermata)
coral (cnidaria/coelenterata)
27. Which of the following is the best index (guide) fossil for bed 2?
A.
B.
C.
D.
28. Which of the following sedimentary environments is suggested by the collection of fossils
shown below?
A.
B.
C.
D.
deep ocean
shallow sea
desert oasis
freshwater swamp
29. The geologist discovered another layer, 10 km away, which contained the following
collection of fossils.
With which of the following beds does the layer correlate?
A.
B.
C.
D.
Bed 2
Bed 3
Bed 4
Bed 5
For questions 30 to 33, refer to the geological columns below
and to the following references in the Data Pages.
Fossil Samples
Geological Time Scale
Reference
Data Pages
Geological columns at widely separated locations.
Note: each layer within a column represents a different unit of geologic time (epoch or period).
Column I
Column II
Column III
green
shale
volcanic
lava
tan
limestone
conglomerate
glacial till
volcanic
lava
Y
red
sandstone
green
shale
grey
siltstone
tan
limestone
brown
sandstone
red
sandstone
conglomerate
mafic dike
green shale
black
shale
grey
limestone
X
grey
siltstone
grey
sandstone
brown
sandstone
tan
limestone
30. What is the oldest layer shown in any of the Columns I, II or III?
A.
B.
C.
D.
glacial till
tan limestone
grey limestone
brown sandstone
31. Which of the following is most likely represented by the wavy line at the base of the
green shale in Column II?
A
B.
C.
D.
joint
varve
thrust fault
erosion surface
32. Which of the following statements is definitely true about fault X-Y in Column I?
A.
B.
C.
D.
after the Oligocene
after the Eocene
after the Paleocene
after the Cretaceous
33. The following radiometric dates were determined for units in Column III.
Method of Dating
Radiometric Age
mafic dike K-40/Ar-40
0.05 million years
glacial till C-14 of tree fragment
0.1 million years
volcanic lava U-235/Pb-207
4.5 million years
Which of the following is the most likely age for the conglomerate in Column III?
A.
B.
C.
D.
Miocene (must be between Oligicene fossil and Pliocene volcanic lava flow)
Holocene
Paleocene
Pleistocene
Use the following photograph to answer question 34.
© Geocomp Media
34. When this fossil was cut in half, no trace of the original structures within the organism
could be seen. Which of the following is the most likely type of preservation of this
organism?
A.
B.
C.
D.
carbonization
cast and mold
permineralization
as original material
Use the following photograph to answer question 36.
© Arthur Holmes
35. The photograph shows a Miocene worm trace fossil. Which of the following statements
about the fossil is true?
A.
B.
C.
D.
No part of the worm has been preserved.
Soft parts were preserved by carbonization.
Hard parts were preserved by permineralization.
The worm has been preserved in its original form.
Reference
Data Pages
For question 36, refer to the fossil diagram below
and to the following references in the Data Pages.
Geological Time Scale
Development of Life Through Time
36. Which of the following is the best estimate of the range of time that this type of organism
existed on Earth? 554mya - 251mya
A.
B.
C.
D.
100 m.y.
200 m.y.
300 m.y.
400 m.y.
Use the following chart to answer questions 37 to 39.
The chart shows how the characteristics of the horse have changed
over several epochs of the Cenozoic Era.
Hyracotherium was about 25 cm in height and Equus had an average height of 150 cm.
Epoch
Horse Form and Name
Equus
Recent
and
Pleistocene
Pliohippus
Pliocene
Merychippus
Miocene
Parahippus
Mesohippus
Oligocene
Hyracotherium
Eocene
© Geocomp Media
Leg
Skull
Teeth
37. Each epoch is represented by a different type of horse. Which geological principle does
this demonstrate?
A.
B.
C.
D.
superposition
faunal succession
original horizontality
cross-cutting relations
38. Which of the following is the best term for the apparent changes that have occurred in the
characteristics of the horse during the epochs of the Cenozoic Era?
A.
B.
C.
D.
evolution
convergence
uniformitarianism
adaptive metamorphism
39. What process would most likely have produced the changes in the horses’ characteristics
during the Cenozoic Era?
A.
B.
C.
D.
sexual reproduction
rapid mass extinctions
gradual natural selection
adaptation over a single generation
40. a) On the grid below, sketch a radioactive decay curve for an element with a half-life of
3 million years. Your sketch must contain a smooth and clearly drawn decay curve
for four half-lives.
(2 marks)
100
Percent radioactive parent
90
80
70
60
50
40
30
20
10
0
0
1
2
3
4
5
6
7
8
9
10
11
12
Time (million years)
Point (3 million years, 50%)
¨ 1 mark
Shape of curve for four half-lives
¨ 1 mark
b) Describe one problem associated with radiometric dating of a sedimentary conglomerate
that has been heavily weathered.
(1 mark)
Any one for 1 mark:
• a conglomerate may contain several types of rock, each with its own age
• dating of a sedimentary rock will generally just give the age of the constituent rocks
• weathering may have removed or added parent or daughter elements thus producing
erroneous dates
• cannot usually date sedimentary rocks because they often do not contain radioactive elements
Geology 12 – 0608 Written-Response Key
Page 5
Use the following geologic cross section to answer question 41.
F
S
I
M
5m
(arranged in random order)
Geologic event
Cross section
symbol
Faulting
F
Igneous intrusion
I
Mafic intrusion
M
Deposition of sedimentary unit
S
41. In the table below, place these geologic events in the order they occurred, with the oldest at
the bottom and the youngest at the top.
(2 marks)
1
2
mark for each correct geological event.
Youngest
I – Igneous intrusion
M – Mafic intrusion
F – Faulting
S – Folding of sedimentary unit
Oldest
© 2005 Province of British Columbia. All rights reserved.
058geol12k – Page 7
Use the following geologic cross section to answer question 42.
Drill hole
Shale
Vesicles
X 125 m.y.
Weathered
and altered
lava
Y 180 m.y.
Lava flow
Z
100 m.y.
Mafic
intrusion
1 2 580 m.y.
460 m.y. 3
4 390 m.y.
300 m.y.
Conglomerate
10 m
42. The diagram shows a hole drilled through layers of rock to a conglomerate.
The potassium-argon method was used to date a buried lava flow at X, Y and Z.
Each measurement was done accurately, but gave different ages for the same formation.
The true age of the lava flow is 180 million years.
a) Choose the lava at either X or Z and explain why its radiometric age differs from the
age at Y.
(1 mark)
Lava location chosen: X
Explanation:
Argon gas may have escaped from the sample causing a younger reading.
Lava location chosen: Z
Explanation:
Contact metamorphism “adjusted” the radiometric date compared to the
samples at Y.
or
Argon gas may have escaped from the sample causing a younger reading.
Lava location chosen: Z
Explanation:
A slight error in depth measurement could mean the second reading might
have come from the mafic intrusion.
© 2005 Province of British Columbia. All rights reserved.
¨ 1 mark
¨ 1 mark
¸ ¨ 1 mark
˝
˛
058geol12k – Page 8
b) Four separate samples of conglomerate were dated using the uranium-lead method.
Their ages were determined to be 300 million years, 390 million years, 460 million years
and 580 million years.
Explain why there are differences in age between the conglomerate samples.
(1 mark)
Different clasts/stones in the conglomerate would yield different ages, not the
age of the conglomerate layer itself.
© 2005 Province of British Columbia. All rights reserved.
¸ ¨ 1 mark
˝
˛
058geol12k – Page 9