Chapter 9

Question 1

The following describes which SS body: Highly cratered surfaces, large ring basins, cracks and scarps, surface is relatively low relief with no major continents for mountain structures

Answer 1

Mercury

Question 2

The following describes which SS body: little surface relief and very few craters of any size

Answer 2

Venus

Question 3

The following describes which SS body: Bright and heavily cratered highlands, and dark smooth maria. Maria cover approx 20% of the surface

Answer 3

The Moon

Question 4

The following describes which SS body: craters, volcanoes, plains, and canyons. Clear signs of evolution caused by a variety of factors including internal heating, tectonics, impacts, wind, and water

Answer 4

Mars

Question 5

The study of rocks, their structure, composition and origin is called

Answer 5

Petrology

Question 6

What is the compositional relationship between rocks and minerals?

Answer 6

Rocks are made of one or more minerals

Question 7

A solid chemical compound that occurs naturally (can be different if they are made of the same components but different structure

Answer 7

Minerals

Question 8

What type of mineral composes the majority of the Earth’s crust and mantle?

Answer 8

Silicate (silicon and oxygen)

Question 9

What are the 3 main families of silicate?

Answer 9

Olivine (most dense), Pyroxene (chains), and Feldspar (least dense)

Question 10

What family of silicates make up approx 60% of Earth’s rock?

Answer 10

Feldspar

Question 11

What are the two categories of feldspar and how are they differentiated?

Answer 11

Othoclase (potassium rich), and Plagioclase (sodium rich)

Question 12

Which mineral is most common on the icy planets?

Answer 12

Water and methane

Question 13

How are rocks classified?

Answer 13

By their mineral content and their formation history

Question 14

What are primitive rocks?

Answer 14

Rocks formed in the protosolar nebula, with element ratios the same as solar abundances (only examples are chondritic meteorites)

Question 15

How is igneous rock formed?

Answer 15

Through the crystallization of rock melted in the crust or upper mantle

Question 16

What are the 2 categories of igneous rock?

Answer 16

Intrusive and extrusive

Question 17

How does sedimentary rock form?

Answer 17

Through the deposition, burial, and lithification of rock that has been weathered through exposure at the surface of the crust

Question 18

What type of rock is biological (fossils of animal shells)

Answer 18

Limestone

Question 19

How is metamorphic rock formed?

Answer 19

Through the recrystalization of minerals under high temperature and pressure in the deep and upper mantle (can also be formed by impact)

Question 20

Give one example of each of the 3 main types of rock

Answer 20

Igneous - Granites, Metamorphic - marble, Sedimentary - sandstone

Question 21

Who discovered the first lunar craters?

Answer 21

Galelio

Question 22

When were the first craters discovered on Earth?

Answer 22

It wasnt until the 20th century

Question 23

What are impact craters circular?

Answer 23

Because the material is blasted out equally in all directions (although the depth may be asymmetrical due to the impact angle)

Question 24

How many times larger are the impact craters relative to the impactor?

Answer 24

Approx 10x larger

Question 25

When are shock waves created by impactors?

Answer 25

When the impact velocity is greater than the speed of sound

Question 26

A highly compressed zone with a high density of energy and matter is what?

Answer 26

A shock

Question 27

What happens to the rock as a shock wave carries the energy of the explosion into the ground?

Answer 27

The rock will compress and deform like a fluid

Question 28

The rebound of the inner material of a crater forms what?

Answer 28

A central peak

Question 29

What for the rim (and maybe rays) around an impact crater?

Answer 29

The fragments that were ejected from the surface

Question 30

What are the 3 steps to finding the impact energy?

Answer 30

1. Find the mass., 2. Find the kinetic energy., 3. Convert to megatons

Question 31

What what velocity must an object be moving to become an explosion upon impact?

Answer 31

3km/s or faster

Question 32

What is the max diameter of a microcrater?

Answer 32

10 microns

Question 33

What property of lunar material can be explained by microcraters?

Answer 33

The age of the lunar material

Question 34

The fine powder created by impacts that covers the surface of the Moon is called what?

Answer 34

Regolith

Question 35

How thick is the lunar regolith on the highlands and the maria?

Answer 35

Approx 2km thick in the uplands and approx 10 m thick over the maria

Question 36

What method of dating craters do we use on inactive worlds?

Answer 36

We can compare the radioactive dating age to the number density of craters on the surface

Question 37

Why cant we use the number density of craters on the surface of active worlds to ascertain an age?

Answer 37

Wind and water erosion can destroy craters (lowering the number density)

Question 38

What can we tell about small craters found on the surface of active worlds?

Answer 38

These craters have to be young (and therefore unaffected by weathering)

Question 39

How can we ascertain the age of other SS bodies if we know their crater number density but cannot gather material for radioactive dating?

Answer 39

We can compare their number density to that of the Moon and extrapolate their age (only for inactive worlds)

Question 40

What is the cratering saturation equilibrium?

Answer 40

When the cratering density gets too high new craters begin to obliterate the old ones and the density reaches a constant

Question 41

What is the minimum age range for SS objects that have reached cratering saturation equilibrium?

Answer 41

3.9-4.5 years old

Question 42

What factor can affect the cratering rate of object?

Answer 42

Proximity to large bodies (more massive bodies attract more asteroids/planetesimals)

Question 43

How do we know that the Marian moon Phobos is very old?

Answer 43

Its surface is heavily cratered

Question 44

How do we know that the Marian moon Deimos is younger than its companion moon, Phobos?

Answer 44

Although it is still very close to saturation, it's surface is less cratered than Phobos

Question 45

What is the relationship in Jupiter's moons between distance from Jupiter and bulk density?

Answer 45

The further the moon is from Jupiter, the lower its bulk density

Question 46

How old are the surfaces of the Galilean moons relative to each other?

Answer 46

Callisto has the oldest surface, Ganymede has some younger areas and some older areas, Europa has a younger surface (fractured and icy) and Lo has a very young face (no impact craters)

Question 47

What type of heating drives all geological heating on Jupiter's moons?

Answer 47

Tidal Heating

Question 48

What feature distinguishes Iapetus (Saturn's moon)?

Answer 48

One side is jet black (possibly dust from another moon, Phoboe) and the other side is bright (water ice)

Question 49

What feature distinguishes Encleadus (Saturn's moon)?

Answer 49

It has plumes (possibly of water) as the result of continuous heating and due to long lived isotopes and tidal forces

Question 50

What is thought to be the origin of Triton (Moon of Neptune) and Pluto?

Answer 50

Thought to both have originally been members of the Kuiper Belt

Question 51

What is the approximate surface area of Mercury?

Answer 51

>3Ga

Question 52

Why cant small meteorites reach the surface of Venus?

Answer 52

These small meteorites cannot penetrate the atmosphere

Question 53

Why is the surface of Venus so young?

Answer 53

There is little erosion but there is much erasure from volcanoes

Question 54

Why is the Earth's crater density lower than that of the Moon?

Answer 54

Because small craters are eroded

Question 55

Which Marian hemisphere is "old and which is "young"?

Answer 55

The south is the "old" half and the north is the "young" half

Question 56

What evidence for the past presence of water do we have on Mars?

Answer 56

We can see splash craters, signs of water erosion, and craters that seemed to have formed in mud