Deck 18: Amazing Ice: Glaciers and Ice Ages

Question 1

Glacial ice exhibits ________ behavior near the top but ________ behavior at a depth of more than 60 m.

A) brittle; plastic
B) plastic; brittle
C) solid; elastic
D) plastic; elastic

Answer 1

A

Question 2

When glacial ice directly evaporates into vapor without melting into liquid water,it is said to be

A) condense.
B) sublimate.
C) volatilize.
D) ablate.

Answer 2

B

Question 3

The polar ice caps on Mars are an example of what type of glacier?

A) continental glacier
B) cirque glacier
C) piedmont glacier
D) valley glacier

Answer 3

A

Question 4

A glacier will always advance from its source area if the rate of accumulation is greater than the rate of ________.

A) subsidence
B) erosion
C) ablation
D) uplift

Question 5

Today,continental glaciers are limited to Antarctica and ________.

A) Alaska
B) Greenland
C) Canada
D) Siberia

Question 6

Boulders left behind by glacial ice,such as these on a hillside in Wyoming,are known as __________.

A) till
B) erratics
C) piedmont
D) horns

Question 7

Large cracks in the surface of glaciers that extend down to the depth where the ice can behave plastically are called

A) fractures.
B) faults.
C) crevasses.
D) moraines.

Question 8

The speed at which ice in a glacier moves is slowest along the sides and bottom due to

A) friction.
B) gravity.
C) calving.
D) sublimation.

Question 9

The last ice age,or time that glaciers covered areas that today have temperate climates,ended ________ years ago.

A) 1,000
B) 10,000
C) 100,000
D) 1 million

Question 10

What kind of information do glacial striations reveal about past glaciers?

A) the temperature of the ice
B) the direction the glacier was moving
C) when the glacier was there
D) how fast the glacier was moving

Question 11

A bowl-shaped depression formed by a mountain glacier is termed a(n)________.

A) arête
B) cirque
C) horn
D) tarn

Question 12

During the last ice age,a ________ glacier covered much of the northern United States.

A) piedmont
B) cirque
C) mountain
D) continental

Question 13

An intermediate product in the transformation of snow to glacial ice is ________.

A) firn
B) deposition
C) ablation
D) terminus

Question 14

Which of the following best describes the direction that glaciers and ice sheets can flow?

A) from areas of high snowfall to areas of low snowfall
B) in the direction pointing toward the coldest air temperature
C) in the direction that is downhill for the land surface under the ice
D) in the direction that its surface slopes

Question 15

Which of the following statements is true of flowing water and glacial ice?

A) Both flowing water and glacial ice are capable of sorting sediments based on clast size.
B) Flowing water will sort sediment based on clast size; glacial ice will not.
C) Glacial ice will sort sediment based on clast size; flowing water will not.
D) Neither flowing water nor glacial ice will sort sediment based on clast size.

Question 16

Glacial deposits consist primarily of __________.

A) fine-grained material
B) coarse-grained material
C) well-sorted material
D) poorly sorted material

Question 17

At depths of greater than 60 m,ice moves by plastic deformation.What causes this transition from brittle to ductile behavior?

A) A decrease in temperature causes the glacier to melt and slide.
B) An increase in pressure increases friction and melts the ice.
C) An increase in the pressure allows for only minute deformation.
D) A decrease in the amount of trapped sediments allows more flow.

Question 18

Cirques and horns are features associated with ________.

A) mountain glaciation
B) continental glaciation
C) glacial outwash deposits
D) loess deposits

Question 19

At the present,glaciers cover about ________ of the surface of the continents.

A) 1 percent
B) 5 percent
C) 10 percent
D) 20 percent

Question 20

What type of glacier is seen in the foreground of the following picture?

A) a continental glacier
B) a cirque glacier
C) a piedmont glacier
D) an alpine glacier

Question 21

What kind of information does a roche moutonnée reveal?

A) the origin of glacial erratics
B) the direction a glacier was moving
C) the climate during a past ice age
D) the height of a glacial moraine

Question 22

The weight of a large ice sheets causes

A) subsidence.
B) volcanoes.
C) subduction zones.
D) metamorphism.

Question 23

If glaciers carry a mixture of different clast sizes,why are glacial outwash deposits layered?

A) because clasts fall out of a glacier in order of size
B) because gravity pulls out only the smallest particles
C) because glacial outwash is formed from the bottom of the glacier
D) because a glacier does not deposit outwash sediments; a river does

Question 24

A hanging valley is formed when a ________.

A) smaller glacially carved valley intersects with a larger glacially carved valley
B) smaller stream-cut valley intersects with a larger stream-cut valley
C) smaller stream-cut valley intersects with a larger glacially carved valley
D) stream-cut valley is on the upthrust side of a normal fault

Question 25

A(n)________ in global sea level is ultimately the result of a ________ event.

A) increase; global cooling
B) increase; local uplift
C) decrease; subsidence
D) decrease; global cooling

Question 26

If you wander around Central Park in New York City,you will eventually encounter random,large boulders that are made of a type of rock not found in the area.How did these large boulders get to Central Park?

A) The Parks and Recreation Department placed them there for kids to play on.
B) They were carried by rivers and deposited in point bars.
C) They were carried by glaciers and dropped as glacial erratics.
D) They were placed there by a giant tsunami millions of years ago.

Question 27

Valleys carved by glaciers tend to be shaped like the letter ________,whereas valleys carved by water tend to be shaped like the letter ________.

A) V; U
B) V; C
C) U; V
D) I; V

Question 28

Underneath their thick ice sheets,the land surfaces of Greenland and Antarctica are

A) made of tall mountains now capped by glacial ice.
B) in large areas mostly below sea level.
C) a flat plain much like the interior of North America.
D) a deep ocean abyssal plain.

Question 29

Stratified sorted sand and gravel are deposited by ________.

A) mountain glaciers
B) continental glaciers
C) glacial outwash streams
D) windstorms

Question 30

Wind blows finer particles long distances from glacial environments,where they settle out to form ________.

A) firn
B) loess
C) outwash
D) till

Question 31

In the figure below,which letter corresponds to an esker?

A) E
B) C
C) A
D) F

Question 32

Which of the following types of glaciers is most likely to carve features such as horns,cirques,and aretes?

A) a continental glacier
B) a piedmont glaciers
C) a mountain glacier
D) an ice cap

Question 33

Sediments deposited directly by glaciers as they melt are characterized by ________.

A) uniformly coarse grain size
B) uniformly fine grain size
C) an absence of sorting
D) graded bedding

Question 34

Which letter corresponds to the furthest reach of the glacier in the figure below?

A) E
B) C
C) G
D) F

Question 35

What is glacial drift?

A) sediment that was deposited by the action of glaciers
B) the side-to-side movement of valley glaciers
C) the cycle of advance and retreat of ice sheets through time
D) the winds that blow across the surface of glaciers

Question 36

What types of moraines are shown as the dark stripes in the figure below?

A) medial moraines
B) terminal moraines
C) lateral moraines
D) recessional moraines

Question 37

Which letter corresponds to where sorted and layered glacial sediments would occur on this landscape?

A) A
B) E
C) G
D) F

Question 38

Sediments deposited directly by glaciers as they melt are ________.

A) firn
B) loess
C) outwash
D) till

Question 39

Cape Cod and Long Island are large examples of what type of features left behind on landscapes after retreat of glaciers?

A) medial moraines
B) terminal moraines
C) drumlins
D) erratics

Question 40

When the sea level rises,causing the ocean to fill a glacially carved valley,a ________ results.

A) cirque
B) tarn
C) fjord
D) estuary

Question 41

What are the circumstances that lead to glacial advance versus glacial retreat? Most glaciers today are in retreat.What does this imply about the glaciers and their environment?

Question 42

What do shorelines of former pluvial lakes in the western United States reveal?

A) that the climate in this region during the last ice age was much wetter than today
B) that this region was below sea level during the last ice age
C) that these lakes were covered by large glaciers
D) the western United States has had essentially the same climate as today for millions of years

Question 43

Contrast global sea level during times of increased glaciation versus interglacial periods,and explain why this occurs.

Question 44

Label the four different types of mountain glaciers shown in the picture below.

Question 45

Describe what you would expect to see in a deposit of glacial till deposit.Why?

Question 46

Imagine that you live in a hot and sunny climate.Painting your roof white would help ________ your house by ________ the albedo.

A) warm; increasing
B) warm; decreasing
C) cool; increasing
D) cool; decreasing

Question 47

Notice the boulders in the center of this picture of a glacially formed landscape.What are they? How did they get there?

Question 48

The effect of periodic changes in the Earth's orbital eccentricity and magnitude and direction (precession)of its axial tilt on the advance and retreat of ice sheets was first proposed by ________.

A) Richter
B) Milankovitch
C) Mohorivic
D) Lyell

Question 49

By increasing the albedo of the Earth,global ice sheets produce conditions that are ________ to their further advance,thus providing an example of ________ feedback.

A) detrimental; positive
B) detrimental; negative
C) favorable; positive
D) favorable; negative

Question 50

How long does postglacial rebound take after continental ice sheets melt?

A) thousands of years
B) millions of years
C) several weeks
D) about one year

Question 51

Explain why the deposits made by glacial outwash are stratified.

Question 52

During the Pleistocene Ice Age,all the climate belts of the northern hemisphere shifted to the __________.

A) north
B) south
C) east
D) west

Question 53

You and some friends are going on a road trip and one of your goals is to see a glacier.Where could you go in the continental United States to do this? What type of glacier will you most likely be visiting?

Question 54

List and describe one short-term cause for glaciations.

Question 55

Imagine you are living in your current home but during the Pleistocene Ice Age.Contrast the present climate with that of your new climate in the Pleistocene.In one sentence,summarize how the climate is different now.

Question 56

The Milankovitch cycles describe the change in ________ caused by cyclical changes in the Earth's orbit around the Sun.

A) greenhouse gases
B) ocean circulation
C) biological diversity
D) solar insolation

Question 57

Contrast a glacially carved valley with one carved by a river.

Question 58

The loss of rainforests would ________ the greenhouse gases,thereby ________ global warming.

A) increase; increasing
B) increase; decreasing
C) decrease; increasing
D) decrease; decreasing

Question 59

The Earth's most recent ice age is called the ________ and began approximately ________ years ago.

A) Holocene Period; 12 thousand
B) Pleistocene Period; 2.6 million
C) Paleozoic Era; 540 million
D) Cenozoic Era; 65 million

Question 60

An important long-term factor that determines whether glacial ice will form on a continent has likely been the proportion of which gas in the atmosphere?

A) oxygen
B) nitrogen
C) carbon dioxide
D) carbon monoxide