Lunar and Planetary Features
Printable Version
In this exercise you will be examining the relative ages of features on the Moon. After that you will
be looking at the different types of features seen on various bodies in the Solar System, such as
the Moon, the terrestrial planets (Mercury, Venus, Earth and Mars), and the satellites of some of
the outer planets.
Part I Stratigraphic Dating on the Moon
Stratigraphic dating is finding whether one feature is older than another based on the idea that
the older feature is UNDER the younger. Stratigraphic dating does NOT give an age in years. It
only gives the older/younger relationship. You will be doing stratigraphic dating on our Moon.
Read about the Moon in your textbook and get a feel for the appearance of different types of
feature. Lunar features that you are likely to see are listed. Look for examples on the photo.
Crater - Lunar craters result from things hitting the Moon. When things hit the Moon, they are
usually going so fast that they are destroyed and a crater about 10 times the size of the impactor
is made. Craters on the moon usually are circular with a raised edge. Small craters are rounded,
like a cereal bowl and have only a slight edge. Larger craters show a depressed center, distinct
raised edges and a central peak or central ring of mountains. The central or ring is due to
material splashing back after the impact.
Mare (plural maria) – Mare regions are areas where very runny lava has flowed. They look flat or
flat with small craters, like the surface of pudding. Usually the lava flow was triggered by an
impact breaking through the Moon’s crust. So look for a crater edge (or part of one) bounding the
mare.
Highland (or terra, plural terrae) Highlands are regions where there are craters, craters and more
craters. There are so many craters that one is on top of another and the circular edges are so
disrupted that you cannot see the shapes. Look for just a jumble. The highlands are large areas
of the Moon. Do NOT use this word to identify specific features of the Moon on your photos.
Mountain- Mountains on our Moon are usually edges of old craters. Later lava flows have
covered the surroundings, leaving just the peaks. So., of course, mountains are always older than
the surrounding mare regions There are hardly any volcanic mountains (called domes) and NO
folded mountains of the type seen on Earth.
Wrinkle ridge-Wrinkle ridges are ridges in mare surfaces. They are usually thought to be due to
shrinkage of the Moon after the mare surface has solidified. Some wrinkle ridges may be caused
by lava flowing and leaving a puddle on the mare surface. Since they are modifications of the
mare surface, they are younger than the mare surface.
Dome- Domes are volcanic mountains. They are very rounded, like half a tennis ball. We have
not seen any eruptions. They are not common.
Rille- A rille is a valley on the Moon. We think that they are due to lava flowing on a mare surface.
The lava melts its way into the surface, leaving the valley. The outside top of the lava trickle
solidifies and the runny lava inside flows out. If the top collapses entirely a rille is left.( If only part
of the top collapses, a chain of craters called a catena can remain .The Moon has NO rivers due
to water that we know of.
Catena (plural catenae) are chains of craters. On the Moon catenae can result from debris
thrown out when a large crater is formed. Or a catena can result when the top of a lava-carved
tube partly collapses.
Planetary Features Lab
1
Documenting Relative Ages-Earth’s Moon
We have no absolute dates for features of most of the bodies in the solar system. We do think
that the feature on top, is the youngest. When features do not overlap, we cannot always tell
which is older. On the Earth we might expect that an older feature might look more worn out, but
there is not so much erosion on other bodies.
You will be deciding on the relative ages of some features on 2 of the images given (there are
more than 2 images, they are in the Moon file). Use a small piece of paper or a 3x5 card to
represent each of the features that you want to explore. Work with your partners to establish
which feature is on top, which on the bottom. Lay out your cards in time order, with the leftmost
position for the oldest and the rightmost for the youngest. If you cannot determine the relative age
of two features, don’t connect them, put one above the other.
Example (not any of the photos): You decide
that features B and D are under feature E. But
neither is under the other. So we don’t know
whether B or D is older, but we know that both
are older than E. Feature F is on top of E and
G on top of F. Feature H is on top of E, but not
on top of either F or G. Feature A is younger
than C and C is beneath J, but none of these
can be related to B or any of the others.
Identify the type of object for each and show
your conclusion for the age relations as shown.
(Remember that this is only an example). The
lines indicate the relationship between
features. To the right is younger. Vertically
displacements (up and down) with NO
connecting line indicate that we cannot tell the
age relationship.
Interpreting the Images
As you look at the images, be careful to distinguish what is sticking out and what is lower than the
surface. Often there is no easy way to tell without making assumptions. Look for shadows and
your knowledge that a crater will have a raised edge and a low middle to find the direction of the
sunlight. There are lots of craters, and basically NO raised things with valleys surrounding them.
Once you know the direction the light is coming from, the shadows should be consistent across
the entire picture.
You may either draw the diagrams on paper or do them on the computer. If you have a word
processor, you may be able to draw this kind of picture (I did) or space out the text. Or you can
use Power Point or Excel. The result will not be too large to email. If you don’t have any of these,
draw it on paper and mail it or drop it in the mailbox at my office.
Check out the photo below. Use it to learn to recognize features and their relationships.
Moon pictures 1. Analyze the ages of the features of TWO pictures by identifying the type of
feature and developing an age diagram for each. Both pdf and gif versions are provided. The
references on the same line are for the same picture. Higher number pictures are easier.
Pic 1 gif
pdf
Pic 5 gif
pdf
Pic 2 gif
pdf
Pic 6 gif
pdf
Pic 3 gif
pdf
Pic 7 gif
pdf
Pic 4 gif
pdf
Pic 8 gif
pdf
2. Write an explanation of how to determine dates on the Moon and how to answer question 1.
Write as though you are explaining to a friend, not to a teacher.
Planetary Features Lab
2
EXAMPLE LUNAR PHOTO
c e
10
10
1
4
8
2
6
5
9
7
3
11
15
1 crater
1
2 crater
13
3 edge of
7
4
submerged
12
8
11
crater
9
4 crater
3
5crater
2
6 crater
Crater 2 might be older than 4,
12
7 partly
but it is so close to 4 that it
submerged probably would have been
destroyed by debris
13 crater
8 mare surface
5
6
9 wrinkle ridge
10 crater
11 submerged
crater
15 14
Craters 5 and 6, and
12 rille
craters 15 and 14 are not
13 rille
overlapping with 4 etc,
14 crater
so we don’t know
the age relationship
15 crater
14
Part 2 Comparing Features of Planets and Moons
As we examine the features found on planets and moons in our solar system, we find both
similarities and differences.
At http://planetarynames.wr.usgs.gov/index.html you will find a gazetteer, a list of names of
features, and maps that you can look at to see the features.
Compare and contrast the features found on several objects. Choose three objects available
from this site. Choose ONLY objects which give the coordinates of features and which have
photos.
Compare and contrast the types of feature found on each of the objects that you have chosen. If
you are working with a partner or several partners, be sure that there is AT LEAST one different
object for each of you.
Look at the list of types of types of feature for your various objects. Use the type of feature to
decide whether they are the same or different.
Consider the features on three different objects. Find four features on each of three objects. Use
objects where latitude and longitude are given and where there are photographs (not every object
has this). Try to find the same type of feature (as identified by the name) on at least two, if not all
of the objects. Try to find a type of feature that is on each object, but not on the others. There
are extra lines in the table, but there should be 12 items total. The names of the features are the
proper names, like Mare Imbrium.
Planetary Features Lab
3
Q3
Name of
Object
Theme of
Names on this
object
Type of
Feature
Type of
Feature
Type of
Feature
Type of
Feature
Type of
Feature
Type of
Feature
Type of
Feature
Type of
Feature
Name:
Name:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Name:
Latitude:
Longitude:
Latitude:
Longitude:
Latitude:
Longitude:
4. Compare the appearance of one type of feature as it appears on two of your bodies. Tell the
type of feature and describe the similarities and differences.
Planetary Features Lab
4
5. Did you find any type of feature of that is on only ONE of the bodies? What kind of feature is it?
(it probably would NOT be in your table)
Part 3 Topographic Maps
Topographic maps are maps of the altitude, height above a reference level. Color indicates the
depth. There is no sea level on any planet except Earth, but there is an average level. You may
be wondering what happened to the topographic maps of the Earth. There are lots and lots of
them, but they are for sale from the US Geological survey. They can even show individual
buildings in rural areas.
Choose three bodies and compare their topographic maps. A list of topographic maps is provided
after the table. It is NOT necessary to use maps of the same objects where you analyzed the
features. A few of the topographic maps have no names for the features. So if you are using one
of these, you will not be able to give names.
Name of body 
Color for the highest
features
Height for the highest
features
Example
of
high
feature
Color for the lowest
feature
Height (below level)
for the lowest level
Example of
low
feature
Reference
you used.
for
Feature name
Feature name
Feature name
Lat.
Long.
Lat.
Long.
Lat.
Long.
Feature name
Feature name
Feature name
Lat.
Long.
Lat.
Long.
Lat.
Long.
map
Maps to use for features and topographic information Please Report Broken Links
Amalthea topographic jpg pdf
Io pdf
Janus topographic jpg pdf
Mars topographic jpg pdf
Mars MOLA (laser altimeter data, much like topographic and usable for topographic) pdf
Mars topographic with names http://ralphaeschliman.com/
Miranda map
jpg pdf
Proteus topographic map jpg pdf
Venus topographic map with names
Venus topographic and relief maps with names http://ralphaeschliman.com/
Planetary Features Lab
5