GEOL 109 EXAM 2 QUESTIONS & ANSWERS
Lesson 16 - Mercury: The Iron Planet
Would you be surprised if tomorrow's newspaper reported that a volcano was
discovered erupting on Mercury? Yes, that is not expected to happen on Mercury today.
Mercury no longer has volcanic activity because its lithosphere is too thick for magmas
to penetrate.
What causes the differences between impact craters on the Moon and those on
Mercury (the extent of the ejecta blanket and secondary cratering)? different
gravitational attractions on each planet
Gravitational pull can affect the extent of crater ejecta and secondary craters. Both of
these craters will extend for greater distances on planetary bodies that have less
gravity.
What do thermal models of Mercury's evolution suggest about its history? That it
developed a metallic core early in its history.
The iron within Mercury separated out into a core early in the planet's history.
The oldest types of terrains on both the Moon and Mercury are
________________________. heavily cratered terrain
Heavily cratered terrain is older than terrain with less craters, since cratering rate has
decreased with time.
Which of the following features are found on the Moon and Mercury? (Check all that
apply) -flood lavas
-multi-ring basins
-impact craters
-faults related to contraction
NOT: dunes
All but dunes are found on both the Moon and Mercury. Dunes do not exist because
there is not atmosphere to move particles to form them.
Which image shows a feature that formed by contraction of Mercury's surface? B
Contraction produces lobate features, while extension produces linear valleys.
Which of the following tectonic processes are thought to have occurred on Mercury?
(Check all that apply) -thrust faulting due to contraction of the planet
-graben formation due to extension
Both extensional and contractional tectonics have occurred on Mercury. Extension
produces graben while contraction produces thrust faults. It is important to remember
extension cannot produce thrust faults nor contractions produce grabens.
, Mercury's smooth plains ____________________. may be similar in origin to the
lunar maria
The smooth plains have few craters compared to the heavily cratered terrain and
resemble the lunar maria.
One of these impact craters is on the Moon and the other is on Mercury. Click on the
one on Mercury. A
Crater A has secondary impacts close to the rim, while B has secondary craters farther
from the crater.
What explains for Mercury's iron large core? Choose the two most likely. -Mercury
formed near the Sun in a zone that was oxygen-poor and rich in metallic iron.
-A large impact stripped away the silicate shell from an already differentiated Mercury.
There are two main theories as to why Mercury has such a large iron core. The first is,
Mercury accreted in an oxygen-poor area that allowed iron to remain in its metallic state
allowing close to all of the iron to segregate in the core.
The second hypothesis is a giant impact knocked off much of Mercury's mantle without
affecting the core, so now the core is large compared to Mercury's diameter.
Lesson 17 - Mars: The Red Planet ...
Although both Mercury and Mars have similar gravity fields, Mars has an atmosphere
whereas Mercury does not. What is a possible explanation? Mars is more volatile rich.
Because Mars accreted further from the Sun than Mercury, Mars has a greater amount
of volatiles. These volatiles were outgassed and released past the surface of Mars
where they were trapped by the gravity field of Mars.
Which planetary body has (basically) no magnetic field today? Mars
Though Mars is larger than Mercury it does not have a present magnetic field. There is
evidence within martian rocks that show there was one in the past, but there is not an
active one today.
Which of the following are important differences between the nature of the martian
hemispheres (north and south)? (Mark all that apply) -ages
-number of young volcanoes and volcanic plains
-elevations
-the number of impact craters
The northern and southern hemispheres are very different in almost every aspect.
Including ages, crater density, volcanic activity, and elevations.
What is the evidence for ground ice (or ground water) on Mars? Choose all correct
answers. -fluidized crater-ejecta patterns
-chaotic (collapse) terrains
Evidence of water on Mars is seen in impact features produced by melted water and the
chaotic terrain produced by flowing water.
Lesson 16 - Mercury: The Iron Planet
Would you be surprised if tomorrow's newspaper reported that a volcano was
discovered erupting on Mercury? Yes, that is not expected to happen on Mercury today.
Mercury no longer has volcanic activity because its lithosphere is too thick for magmas
to penetrate.
What causes the differences between impact craters on the Moon and those on
Mercury (the extent of the ejecta blanket and secondary cratering)? different
gravitational attractions on each planet
Gravitational pull can affect the extent of crater ejecta and secondary craters. Both of
these craters will extend for greater distances on planetary bodies that have less
gravity.
What do thermal models of Mercury's evolution suggest about its history? That it
developed a metallic core early in its history.
The iron within Mercury separated out into a core early in the planet's history.
The oldest types of terrains on both the Moon and Mercury are
________________________. heavily cratered terrain
Heavily cratered terrain is older than terrain with less craters, since cratering rate has
decreased with time.
Which of the following features are found on the Moon and Mercury? (Check all that
apply) -flood lavas
-multi-ring basins
-impact craters
-faults related to contraction
NOT: dunes
All but dunes are found on both the Moon and Mercury. Dunes do not exist because
there is not atmosphere to move particles to form them.
Which image shows a feature that formed by contraction of Mercury's surface? B
Contraction produces lobate features, while extension produces linear valleys.
Which of the following tectonic processes are thought to have occurred on Mercury?
(Check all that apply) -thrust faulting due to contraction of the planet
-graben formation due to extension
Both extensional and contractional tectonics have occurred on Mercury. Extension
produces graben while contraction produces thrust faults. It is important to remember
extension cannot produce thrust faults nor contractions produce grabens.
, Mercury's smooth plains ____________________. may be similar in origin to the
lunar maria
The smooth plains have few craters compared to the heavily cratered terrain and
resemble the lunar maria.
One of these impact craters is on the Moon and the other is on Mercury. Click on the
one on Mercury. A
Crater A has secondary impacts close to the rim, while B has secondary craters farther
from the crater.
What explains for Mercury's iron large core? Choose the two most likely. -Mercury
formed near the Sun in a zone that was oxygen-poor and rich in metallic iron.
-A large impact stripped away the silicate shell from an already differentiated Mercury.
There are two main theories as to why Mercury has such a large iron core. The first is,
Mercury accreted in an oxygen-poor area that allowed iron to remain in its metallic state
allowing close to all of the iron to segregate in the core.
The second hypothesis is a giant impact knocked off much of Mercury's mantle without
affecting the core, so now the core is large compared to Mercury's diameter.
Lesson 17 - Mars: The Red Planet ...
Although both Mercury and Mars have similar gravity fields, Mars has an atmosphere
whereas Mercury does not. What is a possible explanation? Mars is more volatile rich.
Because Mars accreted further from the Sun than Mercury, Mars has a greater amount
of volatiles. These volatiles were outgassed and released past the surface of Mars
where they were trapped by the gravity field of Mars.
Which planetary body has (basically) no magnetic field today? Mars
Though Mars is larger than Mercury it does not have a present magnetic field. There is
evidence within martian rocks that show there was one in the past, but there is not an
active one today.
Which of the following are important differences between the nature of the martian
hemispheres (north and south)? (Mark all that apply) -ages
-number of young volcanoes and volcanic plains
-elevations
-the number of impact craters
The northern and southern hemispheres are very different in almost every aspect.
Including ages, crater density, volcanic activity, and elevations.
What is the evidence for ground ice (or ground water) on Mars? Choose all correct
answers. -fluidized crater-ejecta patterns
-chaotic (collapse) terrains
Evidence of water on Mars is seen in impact features produced by melted water and the
chaotic terrain produced by flowing water.
