Chapter 9

is a high-elevation region dotted by tall volcanoes.

Tharsis Bulge

These four photos show features of Earth that change with time, some fast and some slow. Which one of these features is being shaped primarily by the process we call tectonics?

The Himalayas

This figure summarizes the geological histories of the terrestrial worlds. Based on this figure, what can you conclude?

The most important factor in a planet's geological history is its size.

Under what circumstances can differentiation occur in a planet?

The planet must have a molten interior.

Go to the screen "Mars Mission Landing Sites," and and select Opportunity landing site (2004). Explore all five zoom levels offered, making sure to read the captions at the tops of the screens. Based on the information provided, why was the landing site,called Meridiani Planum, chosen for the Opportunity mission?

The region was already known to have minerals likely to have formed in liquid water.

Why are there fewer large craters on the seafloor than on other continents?

The seafloor crust is younger than the continental crust

This image shows two tall volcanoes on Venus. Why is it yellow?

The yellow color is arbitary because this image was created with radar data rather than visible light.

How have we been able to construct detailed maps of surface features on Venus?

by using radar from spacecraft that were sent to orbit Venus

The core, mantle, and crust of a planet are defined by differences in their

composition.

Australia is composed of relatively old and thick

continental crust

What drives the motion of the tectonic plates on Earth?

convection cells in the mantle

From center to surface, which of the following correctly lists the interior layers of a terrestrial world?

core, mantle, crust

The earthquakes that occur in Southern California generally occur above a

fault

Volcanism is more likely on a planet that

has high internal temperatures.

A planet is most likely to have tectonic activity if it has

high internal temperature.

Old Faithful Geyser at Yellowstone National Park in the United States acquires its energy from a

hot spot

Go to the screen in the interactive figure called "Key Evidence of Water," then zoom in on the "Southern Highlands." Which geologic processes are most clearly evident in the southern highlands?

impact cratering and erosion

The processes responsible for virtually all surface geology are _________.

impact cratering, volcanisms, tectonics, and erosion

Scientists can estimate the age of a planetary surface by counting __________.

impact craters

Heat escapes from a planet's surface into space by thermal radiation. Planets radiate almost entirely in the wavelength range of the

infrared.

How does the amount of heat released in a planet's interior by radioactive decay change with time?

it drops off with time

Which of the following best describes convection?

it is the process in which warm material expands and rises while cool material contracts and falls

Valles Marineris is a

large canyon on Mars

The terrestrial planet cores contain mostly metal because

metals sank to the center during a time when the interiors were molten throughout.

The polar caps on Mars are composed of

mostly solid carbon dioxide and some water ice.

The existence of a core-mantle-crust interior structure tells us that a world __________.

once had a molten interior

How many of the five terrestrial worlds have surfaces being constantly reshaped by plate tectonics?

one

Which internal energy source is the most important in continuing to heat the terrestrial planets today?

radioactivity

The slowly increasing distance between South America and Africa is due to

seafloor spreading

Layered _______ exposed by erosion can be seen when looking at the Grand Canyon in the United States.

sedimentary rock

Olympus Mons is a

shield volcano on Mars

The extremely deep ocean Mariana Trench is a result of

subduction

The Caloris Basin on Mercury covers a large region of the planet, but few smaller craters have formed on top of it. From this we conclude that

the Caloris Basin formed toward the end of the solar system's period of heavy bombardment.

What type of stresses broke Earth's lithosphere into plates?

the circulation of convection cells in the mantle, which dragged against the lithosphere.

Which of the following describes tectonics?

the disruption of a planet's surface by internal stresses

Which of the following describes impact cratering?

the excavation of bowl-shaped depressions by asteroids or comets striking a planet's surface.

Which of the following is NOT an example of tectonics?

the gradual disappearance of a crater rim as a result of wind and rain

Which of the following does not provide evidence that Mars once had large amounts of flowing water?

the presence of vast canals discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell

What is differentiation in planetary geology?

the process by which gravity separates materials according to density

When we see a region of a planet that is not as heavily cratered as other regions, we conclude that

the surface in the region is younger than the surface in more heavily cratered regions

Which of the following describes erosion?

the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather.

The relatively few craters that we see within the lunar maria

were formed by impacts that occurred after those that formed most of the craters in the lunar highlands.

Which of the following most likely explains why Venus does not have a strong magnetic field?

Its rotation is too slow

How did the lunar maria form?

Large impacts fracture the Moon's lithosphere, allowing lava to fill the impact basins.

Which of the following show evidence of ancient river beds?

Mars

This photo was taken from orbit around some planet. What planet is it, and how do you know?

Mars because we see dried up riverbeds.

Rank the five terrestrial worlds in order of size from smallest to largest.

Moon, Mercury, Mars, Venus, Earth

The arrow in this photo is pointing at a feature known as _____________________.

Olympus Mons

The tallest mountain on Mars is called

Olympus Mons

Which of the following Mars surface features provides dramatic evidence that volcanism has played a role in shaping the surface of Mars?

Olympus Mons

What process has shaped Earth's surface more than any other?

Plate tectonics

Assuming that features you see on Mars are similar to features found on Earth, what would a casual inspection of the interactive photo of Mars lead you to suspect about water on Mars?

Surface water only exists as frozen ice.

The major processes that heat the interiors of the terrestrial worlds are ________.

(1) heat deposited as the planets were built from planetesimals; (2) heat deposited as the planets underwent differentiation; (3) heat released by radioactive decay

Percival Lowell's claims of a Martian civilization generated great public interest, but other scientists of his time were highly skeptical of these claims. Which two of the following statements (which are all true) explain why other scientists of the late 19th and early 20th centuries rejected Lowell's claims?

- Lowell's canals followed perfectly straight lines for thousands of kilometers - Lowell's canals did not appear in photographs of Mars taken through telescopes.

Start on the home screen of the interactive figure, with "Elevation is off." Then turn elevation on, and compare what you see. You may wish to switch back and forth between elevation on and off a few times. Then select the statements below that are true. Note: Features such as impact craters that are actually round in shape are distorted into oval shapes at mid- to high-latitudes by map projection effects.

- Most of the northern hemisphere has much lower elevation than the southern hemisphere - Several large volcanoes are found near or somewhat north of Mars's equator - There is a large, roundish region of low-elevation in the southern hemishphere - There is a long, deep canyon that stretches along a region close to Mars's equator.

Go to the screen in the interactive figure called "Major Geological Features." Which of the following statements about the Tharsis Bulge, often simply called "Tharsis," are true?

- One end of Valles Marineris is connected to Tharsis - Tharsis has several large volcanoes - Tharsis has higher elevation than surrounding regions

Go to the screen "Key Evidence of Water," and and select the feature called "Recurring Slope Lineae." Study this feature at each of the four zoom levels offered, and be sure to view the animation called "recurring slope linaea (gif)" that you will see at the third zoom level. Which of the following statements are true?

- The recurring slope lineae look like narrow dark streaks - The recurring slope lineae are found among impact craters - the recurring slope lineae appear to grow in spring and summer

Which of the following statements about our solar system's terrestrial worlds are true?

- They are all of nearly the same age - They are all made primarily of rock and metal - Their interiors all have a core, mantle, and crust

Which feature in this photo of the full moon is one of the lunar maria?

1

Shown following are three terrestrial planets of our solar system. Rank the planets based on the amount of time the surface of the planet has had a moderate to high level of volcanic/tectonic activity, from longest to shortest.

1. Earth 2. Mars 3. Mercury

Each of the following statements is best associated with one of the four major geological processes. Drag each statement into the correct bin for its associated process.

1. Impact Cratering - mostly occured during heavy bombardment, affected all solid worlds similarly. 2. Volcanism - created the smooth lunar maria, erased virtually all craters on lo, responsible for all the existence of Earth's atmosphere and oceans. 3. Tectonics - On Earth, involves motion of plates, includes surface compression that builds mountains 4. Erosion - includes features sculpted by wind.

Each statement below represents a feature that has been claimed to exist on Mars. Sort the statements into the correct bin according to whether each is a feature that actually exists, that does not actually exist, or that might exist but about which we cannot yet draw a definitive conclusion.

1. Real Mars - minerals of types known to form in liquid water, abundant water ice, dried-up river beds 2. Imaginary Mars - frequent rainfall and snowfall, surface pools of liquid water, cities built by an ancient civilization, a network of straight-line canals 3. Unknown Mars - underground pockets of liquid water, microscopic life

Shown below are the four terrestrial planets of our solar system. Assume that all the planets started out equally hot inside. Rank the planets based on their expected cooling rates, from fastest cooling to slowest cooling.

1. mercury 2. mars 3. venus 4. earth

About how large (on average) is an impact crater compared to the size of the impactor?

10 times larger

This diagram represents the conveyor-like action of plate tectonics on Earth. Which numbered position represents a place where new seafloor crust is being made?

2

What are the basic requirements for a terrestrial world to have a global magnetic field?

A core layer of molten, convecting material, and sufficiently rapid rotation

Which internal energy source produces heat by converting gravitational potential energy into thermal energy?

Accretion and differentiation

The image below shows a rock formation nicknamed "the face on Mars" that was taken by the Viking 1 orbiter in 1976. Given the clear resemblance to a face, what is an appropriate scientific reaction to this image?

Assume it is most likely a coincidental result of light and shadow, and plan higher resolution follow-up observations.

What kind of surface features may result from tectonics?

Cliffs, mountains, volcanos, valleys (all of the above)

Which two properties are most important in determining the surface temperature of a planet?

Distance from the Sun and atmosphere

Which of the terrestrial worlds has the strongest magnetic field?

Earth

Choose the correct description of the conveyor-like action of plate tectonics on Earth.

Earth's lithosphere is broken up into plates that float on the underlying mantle. The tops of the mantle's convection cells drag the bottoms of the plates, making them move. This movement causes spreading in some places and subduction in others.

How does it explain the differences between seafloor and continental crust?

Every time a bit of rock is subducted and expelled, its chemistry changes, making it lighter. The lighter rock becomes the continental plates, while the relatively unprocessed rocks are the seafloor plates.

The magnetic and rotational north poles on Earth are the same. True or False?

False

There is no erosion of surface features on the Moon. True or False?

False

The large, roundish, low-elevation region in the southern hemisphere is called

Hellas Basin

Why does Earth have the strongest magnetic field among the terrestrial worlds?

It is the only one that has both a partially molten metallic core and reasonably rapid rotation.

Which describes our understanding of flowing water on Mars?

It was important once, but no longer.

Why does the Moon have a layer of powdery "soil" on its surface?

It's the result of gradual erosion by micrometeorites striking the Moon.

Which of the following best describes the lunar maria?

Relatively smooth, flat plains on the Moon.

_______ found in the Atlantic Ocean between North American and Europe is composed of dense and relatively young rock.

Seafloor crust

Which of a planet's fundamental properties has the greatest effect on its level of volcanic and tectonic activity?

Size

Spacecraft have landed on all the terrestrial worlds except

Spacecraft have landed on all of the terrestrial worlds.

Which of the following best describes why the smaller terrestrial worlds have cooler interiors than the larger ones?

They have relatively more surface area compared to their volumes.

What is the significance of the yellow lines on this map of Earth?

They represent boundaries between the plates that make up Earth's lithosphere.

Why do we think Mercury has so many tremendous cliffs?

They were probably formed by tectonic stresses when the entire planet shrank as its core cooled

This photo from the Curiosity rover shows what appears to be layered sedimentary rock on Mars. What does this photo seem to be telling us?

This region of Mars once held a body of water such as a lake.

Earth is the only planet in the solar system known to have plate tectonics. True or False?

True

Mars has virtually no magnetic field. True or False?

True

Spacecraft have landed on all the terrestrial worlds. True or False?

True

The long, deep canyon running along the equator is called

Valles Marineris

What are the conditions necessary for a terrestrial plaent to have a strong magnetic field?

both a molten metallic core and reasonably fast rotation.

What do we mean when we say that the terrestrial worlds underwent differentiation?

When their interiors were molten, denser materials sank toward their centers and lighter materials rose toward their surfaces.

How fast do plates move on Earth?

a few centimeters per year

Based on its surface features, the most important event on Venus in the past billion years or so was _______.

a global "repaving" that erased essentially all the surface features that had existed earlier

A terrestrial world's lithosphere is ________.

a layer of relatively strong, rigid rock, encompassing the crust and part of the mantle.

In the context of plate tectonics, what is a subduction zone?

a place where a seafloor plate is sliding under a continental plate

The three principal sources of internal heat of terrestrial planets are

accretion, differentiation, and radioactivity

The geological feature in this photo is _________.

an impact crater