GEOLOGY 306 Laboratory
Instructor: TERRY J. BOROUGHS
NAME:
Examining the Terrestrial Planets (Chapter 20)
For this assignment you will require: a calculator, colored pencils, a metric ruler, and your geology 305
textbook as a reference. Objectives for chapter 20: After you have completed this exercise, you should
be able to: 1. List and describe the geologic processes that have shaped the landforms of the terrestrial
planets; 2. Give an example of a feature on Earth or the Moon produced by each of the geologic processes
that have shaped the landforms of the terrestrial planets; 3. List the primary geologic processes that have
shaped the landforms of each of the terrestrial planets; 4. Describe the procedure for determining the
relative ages of a planet’s surface features.
The following questions refer to Chapter 20, (PAGES 267 – 279 IN YOUR MANUAL, 7th Ed.) or
(Pages 325 - 340 in your manual, 8th edition)
(Read the questions from your manual and place your answers in the following spaces provided.)
1.
Identify the geologic processes that modified the landscapes of the Earth and the Moon depicted in
the following figures and/or photographs. The processes involve include the following: Volcanism,
Tectonism (evidence of plate tectonics), Gradation (leveling of the surface due to erosion and
deposition), and Impact Cratering.
Figures and/or photographs
Identify the geologic processes that modified these
surfaces and/or landscapes (use Volcanism, Tectonism,
Gradation, or Impact cratering
Fig. 20.1 A & B
Fig. 20.2
Fig. 20.3 & 20.4
Fig. 20.5
Smooth, dark areas of central figure in Fig. 20.6
Fig. 20.6 A
2.
Indicate the agent of gradation and/or specific process (if known) that is responsible for the feature
the following figures:
Figures and/or photographs
Identify the agent of gradation and/or specific process (if
known) that is responsible for the feature
Fig. 20.3
Fig. 20.4
Inside the crater of Fig. 20.6 A
Impact craters and volcanoes can both have craters. One has its crater rim along the ground’s
surface, whereas the other has its crater up atop a cone.
The crater rim for an impact site is typically located:
3.
The crater rim for a volcano is typically located:
Instructor: Ms. Terry J. Boroughs
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4.
Meteor Crater, Figure 20.5, has a diameter of approximately 1,200 meters. It is estimated that the
object that produced it was about 25 meters across.
How may times greater is the size of the crater than the object that produced it?
Such a small object can produce such a large crater due to (high velocity, high momentum, high mass, or
a combination of all of these.) (Pick the best answer.)
5.
Despite being one of the best-preserved and youngest impact craters on Earth, Meteor Crater,
Figure 20.5, shows signs or erosion. Do you see signs of weathering and erosion in the form of dry
stream channels cutting through the rim of the crater, or debris from rock falls and/or rock slides at
the base of the crater walls, or do you see a combination of both?
6.
Which Lunar feature (figure 20.6 a, b, c, or d) most resembles Meteor Crater?
8.
How are the surfaces of Mercury and the Moon similar? (What do they have in common?)
9.
Figure 20.7A shows a close-up view of a portion of Mercury’s surface. It is similar to certain features
found on the Moon. Which figure of the Moon (Figure 20.6 A, B, C, or D) shows a feature similar to
figure 20.7A? (Pick the best answer.)
10. Figure 20.7B shows a close-up view of a portion of Mercury’s surface. It is similar to certain features
found on the Moon. Which figure of the Moon (Figure 20.6 A, B, C, or D) shows a feature similar to
figure 20.7B? (Pick the best answer.)
11. Of the four processes that alter a planet’s surface, which one the most effective on Mercury? (In
other words, which process is readily visible or common on the surface of Mercury?)
12. Why does Mercury show little evidence of erosion due to running water, wind, or ice?
13. Choosing from the processes that act on a planet’s surface, (volcanism, tectonism, gradation, impact
cratering) write the name of the process that is most likely responsible for the features in the
following figures on Mercury. Be specific, for example, Gradation – wind vs. Gradation – ice.

Figure 20.7 A:

Figure 20.7 D (flat areas in lower left corner):
Instructor: Ms. Terry J. Boroughs
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14. Using these images of Mercury, figure 20.7C notice the trace of a cliff-like structure that has offset
more than 1.6 kilometers (1 mile). Which of the four major geologic processes (volcanism, impact
cratering, gradation, or tectonism) created this structure? (Pick the best answer.)
15. Using the full-disk image of Venus and the smaller images in Figure 20.8, do you see any of the
following processes (volcanism, impact cratering, gradation, or tectonism) evident on the surface of
Venus?
Volcanism (yes or no):
Impact cratering (yes or no):
Tectonism in the form of fracturing or faulting (yes or no):
Gradation (yes or no):
If yes, what type(s)?
16. Choosing from the processes that act on a planet’s surface, (volcanism, tectonism, gradation, impact
cratering) write the name of the process that is most likely responsible for the following features
(volcanism, impact cratering, gradation, or tectonism) evident on the surface of Venus?

Figure 20.8 A:

Figure 20.8 B:

Figure 20.8 C:

Figure 20.8 D:
17. In radar images, smooth surfaces appear darker, and rough, multi-faceted surfaces appear bright.
These differences are not due to compositional differences like seen on the Moon, but instead due to
the effects of weathering, erosion, etc.
Do you think that the smooth surfaces are (Older or younger?) Pick one.
Do you think that the rough surfaces are (Older or younger?) Pick one.
18. The gradational agent responsible for the streak like feature in Figure 20.8 D is:
19. A. Is the central feature in Figure 20.8 C younger or older than the surrounding landscape? B. What
type of structure is this feature?
A.
B.
20. The bright areas on the central global view of Venus (figure 20.8) show highly fractured ridges and
canyons of the Aphrodite highlands. What geologic process produced these features: (volcanism,
tectonic activity, gradation, or impact cratering)? (Pick the best answer.)
Instructor: Ms. Terry J. Boroughs
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21. Approximately 1000 impact craters have been identified on the surface of Venus. Do think this is
(more or less) than the number on the surface of Mercury?
22. Identify the geologic processes that modified the landscapes of Mars depicted in the following
figures and/or photographs. The processes involve include the following: Volcanism, Tectonism
(evidence of plate tectonics), Gradation (leveling of the surface due to erosion and deposition), and
Impact Cratering.
Identify the geologic processes that modified these
surfaces and/or landscapes (use Volcanism,
Tectonism, Gradation, or Impact cratering
Figures and/or photographs
Fig. 20.9 A
Fig. 20.9 B
Fig. 20.9 C
Fig. 20.9 E
23. Using the full-disk and the smaller images of Mars in or figure 20.9, do you see any of the following
processes (volcanism, impact cratering, gradation, or tectonism) evident on the surface of Mars?
Volcanism (yes or no):
Impact cratering (yes or no):
Tectonism in the form of fracturing or faulting (yes or no):
Gradation (yes or no):
If yes, what type(s)?
24. How does the Martian surface compare to the surfaces of Mercury and Venus in regards to crater
density (the number of craters in a given area)? Does Mars have more or fewer craters than
Mercury?
25. Choosing from the gradational processes that act on the surface of Mars, write the name of the
process that is most likely responsible for the features in the following figures. Be specific, for
example, Gradation – wind vs. Gradation – ice.

Figure 20.9 A:

Figure 20.9 E:
26. The long linear feature near the center of the full-disk image of Mars is Valles Marineris, a large
canyon system. Do you think Valles Marineris is (larger or smaller) than the Grand Canyon located
in the U.S. (Pick the best answer.)
27. Do you think that Valles Marineris may have formed from tectonic activity? Do you think this tectonic
activity is currently active?
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Instructor: Ms. Terry J. Boroughs
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28. Because the subsurface of some regions on Mars contains abundant ice, impacts often generate
ejecta with a mud-like consistency. Do you think the impact crater shown in figure 20.9 B exhibits
this type of ejecta pattern? (yes or no)
29. Using Figure 20.9 C, Olympus Mons is one of four huge volcanoes in a region called Tharsis.
Compare the surface of Olympus Mons to the surface of Mercury and the lighter regions of the
Moon. Is the surface of Olympus Mons geologically (young, old, or about the same age) as the
surfaces of Mercury and the lighter regions of the Moon? (Pick the best answer.)
30.
Using Figure 20.6 Describe the origin and/or characteristics of the Lunar Maria and Lunar
Highlands.
Maria:
Highlands:
31. Rocks brought back from the lunar Maria during the Apollo landings are about 3.2 - 3.8 billion years
old. Therefore, are the lunar highlands (older or younger) than 3.2 - 3.8 billion years. (Pick the best
answer.)
32. List these lunar features in order, from oldest to youngest: maria, highlands, rayed craters.
Youngest:
33.
Middle:
Oldest:
Are the rayed craters older or younger than the area around them? (Pick the best answer.)
34. Based upon the density of craters, the surface of Mars appears to be (older, younger, about the
same age) as the Moon’s highlands and (older, younger, about the same age) as the surface of
Mercury. Write your answers here, don’t circle them.
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35. Considering its history, describe how the surface of Mercury is likely to change during the next billion
years.
36.
On a global scale, which planet looks more like Venus: Mercury or Mars?
37. Place the four terrestrial planets and our moon into sequence from the oldest, less modified surface
to the youngest, most modified surface.
Youngest:
Instructor: Ms. Terry J. Boroughs
: Oldest
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38. Of the four terrestrial planets which is the:
Least active:
Most Active:
39. Using figure 20.12 Compare the southern half of the photograph to the northern half. Which surface
is older?
Northern ½ or Southern ½ is older?
How did you know?
40. Using figure 20.12, How do you know that the craters in the Southern ½ are of various ages?
Extra Credit Questions from page or 279 (Summary / Report Page for chapter 20):
1. What are the four major geologic processes that have shaped the surfaces of the terrestrial planets
and the Moon? Give examples of landforms produced by these processes.
2.
Process:
Example landform:
Process:
Example landform:
Process:
Example landform:
Process:
Example landform:
The surface of the Moon most resembles the surface of (Mercury, Venus, or Earth) whereas the
surface of Venus is similar to that of (Earth or Mars)?
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3.
Which planet’s surface has been mapped exclusively by Radar? Why is radar mapping used?
4.
List the most significant geologic processes that shape or has shaped the surface of each of the
terrestrial planets and the Moon.
Most significant process on Earth:
Most significant process on Mercury:
Most significant process on Venus:
Most significant process on Moon:
Most significant process on Mars:
Instructor: Ms. Terry J. Boroughs
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5.
Of the major gradational agents, (running water, gravity, wind, or ice) is the only one that alters the
surface of all the terrestrial planets? (I.e. all terrestrial planets exhibit this gradational agent. (Pick the
best answer.)
6.
Using images from Mars figure 20.11 (B), do you think that these elongate and irregular features
were produced by gradation and if so, specify the type of gradational process involved.
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7.
Briefly describe how the relative ages of various planetary surfaces can be determined. (I.E. what
type of features or surface characteristics would indicate older surfaces vs. younger surfaces?
Examining the Terrestrial Planets Lab Supplement
1. Tectonism / Tectonic activity
A. Involves the movement of crustal rock by fracturing, faulting, or folding
B. Can exhibit the following:





Linear or gently curving factures and/or faults
Fault scarps
Folded terrain
Mountain belts, mountain ranges
Linear ridges
2. Volcanism
A. Volcanism is the eruption of molten rock material (magma) and its associated gases, ash,
etc. onto a planet’s surface.
B. Can exhibit the following:

Steep, conical hills with summit craters or large caldera

Calderas form as a result of summit collapse and may exhibit fractures in a
concentric ring shape.

Lava flows which can produce a lobe-shaped deposit with an undulating surface.

Lava flows that fill craters and leave behind a smooth surface
3. Impact Cratering
A. Impact craters are the consequence of rapidly moving meteorites and/or asteroids that strike
the surface of a planet.
B. Can exhibit the following:




Central peaks or pinnacles in the center of the crater
Ejecta blankets
Ejecta rays
Ringed crater rims



Overturned crater rims
Overlapping crater rims
Crater chains, etc.
Instructor: Ms. Terry J. Boroughs
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4. Gradation
A. The process that levels a surface to a common elevation by erosion and deposition is
controlled by the surface environment. Gravity, temperature, and the presence of an
atmosphere all play key roles.
B. The major agents of gradation include the following:




Running water

Eroded stream channels

Delta deposits

Alluvial fans

Lake sediments

Ocean sediments, beaches, etc
Gravity

Materials become eroded and fall, flow, etc. due to the influence of gravity
and include:

Talus slopes (material collecting at the base of a steep surface, such as a
cliff face or the walls of an impact crater

Landslides, mudflows, avalanches, etc. often triggered by excess water

Crater rims will become eroded and debris will start to fill the crater with
eroded material, often burying the central peak, which can also become
eroded

All of the terrestrial planets have mass and therefore gravity!!!
Wind

Wind requires and active atmosphere

Typically only the fine-grained particles will be carried by the wind

May produce wavy sand dunes

May produce streaks of sediment when the wind carries some of the ejecta
material in one direction, following an impact by a meteorite

Requires the presence of water and other atmospheric compounds

Ice is often very reflective and may appear white in pictures

Ice and glaciers are very effective for scouring a surface flat and evening out
the landscape.

Often found closer to the polar regions of the Earth.
Ice
Instructor: Ms. Terry J. Boroughs
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