Unit C Review Questions
1. Students will fill in this chart while watching “Geomorphology.”
Era
Period
Time
Frame
(Millions
of Years
Before
Present)
Environmental
Conditions
Events and
Life Forms

4500
volcanic, hot
to 590
Precambrian



Cambrian
590 to
sea
500




Ordovician/
Silurian
500 to
sea
410




life begins in
sea
algae, bacteria,
primitive worms
Devonian
Carboniferous
Mesozoic
410 to warm, shallow
360
sea
shallow
360 to
tropical
290
seas
Permian
huge swamps,
290 to
but largely
250
marine
Triassic
250 to supercontinent
none
explosion of life
increase in
atmospheric
oxygen
jellyfish
crustaceans
snails
none
ammonoides
(ammonites)
crinoids
eurypterids
water scorpions
corals
Paleozoic


Societal
Connection
(Fossil Fuels)
predatory fish
large carbonate
reefs

carbonate shells


giant dragonflies
fin-backed
reptiles

large reptiles
none

much of
Alberta’s
oil and
gas
deposits

first oil
discovere
d from
this time
period
none

oil and
210
Jurassic
(Pangaea)
210 to marine, shore,
140
continental

early dinosaurs

dinosaurs ruled

dinosaurs
continue to
roam
T-Rex
triceratops
duck-bill
dinosaurs
flowering plants
snakes
Rocky Mountain
building starts
major extinction
caused by
asteroid impact
and cooling
climate



Cretaceous
140 to
inland sea
65




Tertiary
65 to
1.7
Cenozoic
Quaternary
warm,
swampy
forests
transitioning
to cooler
grasslands
ice ages, ice
1.7 to
sheets,
present
glaciers




gas

oil and
gas


oil sands
oil and
gas
coal

rise of mammals
dominance of
grasses and
grazing
mammals
mammoths
80 000 years
ago last ice age
begins
none
none
2. Students will fill in this table to summarize the important concepts of Unit C. One possible set
of answers is shown.
Concept
Explanation
Earth’s history
has occurred
challenges of over billions of
investigating
years and is
changes to
recorded all
Earth’s crustal across the planet
plates
in sedimentary
rocks thousands
of metres thick.
evolution of
geological
process
theories
Over the past
300 years, new
theories have
developed and
Connection to
Technology and/or
Society
Examples

most rocks and fossils
from early in Earth’s
history destroyed by
rock cycle

uniformitarianism
versus catastrophism
development of plate
tectonic theory


new technological
advances—groundpenetrating radar,
GPS satellites,
radiometric-dating
techniques help
scientists overcome
challenges



computer modelling
mass spectrometer
seismometers
continue to
change in light
of new evidence.


development of
radiometric dating and
dating Earth’s age
various theories
concerning climate
change
energy
released by
earthquakes
Seismic waves
travel out in all
directions from
the epicentre.



P-waves
S-waves
surface waves
layers for
Earth’s
internal
structure
The internal
structure of
Earth is
composed of
layers.




inner core
outer core
mantle
crust
Crustal plates
float and move
plate tectonics
on Earth’s
mantle.


sea-floor spreading
subduction
driving force
for plate
tectonics
Convection
currents push
and pull on
Earth’s tectonic
plates.

Juan de Fuca Plate
being subducted under
North American Plate
determining
absolute age
This is
determined by
finding the age
in years of rocks
or fossils.



radiometric dating
uranium
carbon
fossilization
Information
about once-living
organisms is
preserved in
layers of
sedimentary
rock.






moulds
imprints
tracks
trails
burrows
actual remains
determining
relative age
This is a matter
of determining
which rock layer
or fossil is older
or younger.

principle of
superposition
evidence of
past climates
Rock features
and composition

mud cracks







GPS
ground-penetrating
radar
satellite imaging
computer modelling
uncertainty
concerning theories
about climate changes
affects public policy
technology used to
track earthquakes
lives saved by
earthquake
predictions

seismic waves used to
probe internal
structure of Earth

predictions of volcanic
eruptions save lives
GPS used to track,
predict plate
movement


lava lamp also works
using the concept of
convection

new technologies—
mass spectrometer

fossil fuels Alberta’s
main energy source
presence of fossils in
drill-core samples—a
useful indicator of
petroleum


used to correlate drill
cores for oil
exploration

understanding climate
in rocks
can indicate the
characteristics of
climate.
atmosphere’s
composition
affected by
life forms
Organisms
exchange gases
with the
atmosphere.
evidence of
repeated
glaciations in
Alberta
Glaciations occur
when ice sheets
advance to cover
much of Canada,
and then they
retreat.
ice cores
show
evidence of
warming,
cooling
several
theories about
causes of
climate
change exist
Continental ice
sheets and
glaciers reveal
the records of
annual snowfall.
Several cold
periods in
Earth’s history
each contained
repeated
glaciations.




salt deposits
limestone
marine fossils
oxygen-18: oxygen-16
ratios from ocean
sediments

cyanobacteria help
provide oxygen to
early atmosphere
exponential increase in
atmospheric CO2 from
burning fossil fuels






drumlins
eskers
kames
kettles
till deposits

Vostok ice core from
Antarctica record of
420 000 years climate
and atmospheric
composition

plate tectonics affect
continent position,
ocean currents
Milankovitch theory
variations in solar
radiation (sunspots)
changes in
atmospheric
composition (carbon
dioxide)
enhanced greenhouse
effect




changes of past helps
scientists predict
changes in future and
determine extent and
nature of human
impacts on climate

human-induced
enhanced greenhouse
effect

sharp peaks of
Alberta’s mountains
largely due to
glaciation
much of Alberta’s
drinking water from
glaciers


Vostok ice core used
to support theories
about causes of
climate change—used
to make predictions
concerning climate
change

theories about causes
of climate change
form foundation for
models used to predict
future climate
change—public policy
based on scientific
data concerning
degree of human
influence on global
climate
3. James Hutton is credited with the theory of uniformitarianism.
4. The theory of uniformitarianism argues that Earth’s history of change can be explained in
terms of geological processes still in operation.
5. The layers listed in order from oldest to youngest are C, B, and A.
6. The law of superposition had to be applied to answer question 5.
7. First, the layers of sedimentary rock (now tilted) were laid down at the bottom of an ancient
ocean. They were then tilted by tectonic processes. After a period of erosion, the tilted layers
were covered by glacial till during the last glaciation. Water erosion later cut out the
outcropping.
8.
9.
10.
11.
Fossil 1 is younger than fossil 2, according to the law of superposition.
The Tertiary Period is part of the Cenozoic Era.
Layer C is between 140 and 65 million years old.
The boundary between layers A and B is called an unconformity. The presence of boulders
and gravel in layer A suggests the unconformity was caused by glaciation.
12. Parent material: 93%
According to the decay curve, 0.10 half-lives have elapsed.
Age = (0.10 half-lives)(7.04 × 108 a/half-lives)
Age = 7.0 × 107 a or 70 million years old
Layer C is 70 million years old.
13. The date determined in question 12 is absolute.
14. Layer A is glacial till that was likely deposited during the last glaciation.
15. The last glaciation ended approximately 10 000 years ago, so it was likely deposited shortly
before that time.
16. a.
b.
c.
17.
18.
19.
20.
7
3
5
d.
e.
f.
1
4
6
g.
h.
i.
8
2
9
D
A
A
Answers will vary but could include one of the following:

The organism is buried rapidly by fine material before the remains are subjected to
the effects of scavengers and decomposition.

The organism must be in an environment that is favourable to preservation when it
dies (low oxygen, smothered in tree sap, freezing, etc.).
21. Answers will vary but could include the following:

Various rock units correlate with each other (must give examples such as sandstone
layers or lava flows).

The ages of the volcanic lava match.

The pattern of magnetic reversals (paleomagnetism) matches.

The overall pattern of rock units correlate well, from lava flow downward.
22. Answers will vary but could include the following:


The rate of sea-floor spreading was faster during the reversed period.
The period of magnetic reversal lasted longer than the normally magnetized period.
23. The geological columns are almost identical until the top of the 20 million-year-old lava flows.
The rock units then begin to differ. The top lava flow is 20 million years old, so the separation
would have started after the lava flows formed.
24. a.
b.
Graph II
Graph III
c.
Graph I
25. Each of these topics has a controversial aspect to the suggested connection between climate,
human activity, and culture. Students should be encouraged to identify sources that
support—as well as sources that challenge—the validity of these connections.
26. Students will evaluate their time lines according to the scoring rubric presented in the
textbook.
Science 20 © 2006, Alberta Education