Deck 13: Glaciers and Ice Ages

Question 1

The end, or the foot, of a glacier is the ____________________.

Answer 1

terminus

Question 2

A series of lakes in a glacial valley that are strung out like beads and connected by short streams and waterfalls are called ____________________.

Answer 2

paternoster lakes

Question 3

Glaciers move by ____________________ when an entire ice mass slides over bedrock.

Answer 3

basal slip

Question 4

____________________ is any rock or sediment that is transported and deposited by a glacier or by glacial meltwater.

Question 5

A glacier that covers an area of 50,000 square kilometers or more and spreads outward in all directions under its weight is a(n) ____________________.

Question 6

A ridge of till in the center of an alpine glacier that is formed when two lateral moraines merge is called a(n) ____________________.

Question 7

The type of glacier movement in which ice flows as a viscous fluid is called ____.

A) basal slip
B) brittle deformation
C) elastic deformation
D) plastic flow

Question 8

A(n) ____________________ is a massive, long-lasting accumulation of compacted snow and ice that forms on land and moves downslope or spreads outward under its own weight.

Question 9

A(n) ____________________ is a fracture or crack in a glacier that forms when the glacier flows over uneven bedrock.

Question 10

A sharp, pyramid-shaped rock summit where three or more cirques intersect near the summit is a(n) ____________________.

Question 11

A glacier that forms in mountainous terrain and covers an area of less than 50,000 square kilometers is a(n) ____ glacier.

A) alpine
B) continental
C) ice sheet
D) erratic

Question 12

A broad, gently-sloping surface that forms when outwash spreads onto a wide valley beyond a glacier is a(n) ____________________.

Question 13

A small glacial valley lying high above the floor of the main valley is called a(n) ____________________.

Question 14

The most recent series of glaciations occurred during the ____________________ Epoch.

Question 15

The ice sheets of Greenland and Antarctica contain ____ percent of the world's ice.

A) 25
B) 75
C) 50
D) 99

Question 16

The lower-altitude portion of an alpine glacier where more snow melts in the summer than accumulates in the winter is called the ____.

A) zone of ablation
B) cirque zone
C) zone of accumulation
D) equilibrium altitude line

Question 17

A(n) ____________________ is a long, snake-like ridge formed as the channel deposit of a stream that flowed within or beneath a melting glacier.

Question 18

The elliptical shape of Earth's orbit around the Sun is its ____________________.

Question 19

____________________ is a glacial deposit that was deposited so long ago that it became lithified into a rock.

Question 20

The relative rates of basal slip and plastic flow depend on the ____ of the bedrock underlying the glacier, the ____ of the ice, and the temperature of the glacier.

A) steepness; age
B) thickness; thickness
C) steepness; thickness
D) age; steepness

Question 21

A(n) ____ is a section of a glacier consisting of numerous crevasses and towering ice pinnacles.

A) snow line
B) terminus
C) zone of accumulation
D) tail

Question 22

Rocks embedded in the base of a glacier scrape across underlying bedrock, gouging parallel grooves and scratches are called ____.

A) crevasses
B) erratics
C) cirques
D) striations

Question 23

The ____ is the boundary between the zone of accumulation and the zone of ablation.

A) equilibrium altitude line
B) terminus
C) brittle zone
D) medial moraine

Question 24

Glacier-carved valleys are typically ____.

A) V-shaped
B) very narrow
C) U-shaped
D) similar in appearance to valleys carved by steep mountain streams

Question 25

A moraine that forms when a glacier is at its greatest advance is a ____.

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

Question 26

Crevasses form in the ____.

A) lower plastic zone of a glacier
B) lower brittle zone of a glacier
C) brittle upper 40 meters of a glacier
D) brittle lower 40 meters of a glacier

Question 27

The higher-altitude portion of a glacier where snow accumulates from year to year and forms glacial ice is called the ____.

A) the zone of ablation
B) equilibrium altitude line
C) the zone of accumulation
D) terminus

Question 28

Snow can form into rounded ice grains, called firn, if ____.

A) it survives through one summer
B) it survives through one winter
C) it falls on basal ice
D) at least 100 feet of snow accumulates on top of it

Question 29

____ is sediment that was first transported by a glacier and then transported and deposited by a stream.

A) Bedrock
B) Till
C) Stratified drift
D) Loess

Question 30

A(n) ____ is a sharp, narrow ridge of rock between two glacial valleys.

A) tarn
B) horn
C) arête
D) fjord

Question 31

A ____ moraine forms when a glacier retreats steadily, depositing till in a relatively thin layer over a broad area.

A) medial
B) terminal
C) recessional
D) ground

Question 32

A(n) ____ is a small lake at the base of a(n) ____.

A) tarn; cirque
B) tarn; crevasse
C) arête; horn
D) arête; cirque

Question 33

A thick mass of ice that floats on the ocean surface but is connected to and fed from a glacier on land is called a(n) ____.

A) ice shelf
B) iceberg
C) outwash plain
D) fjord

Question 34

A spoon-shaped depression that was eroded into a mountain peak by a glacier is a(n) ____.

A) cirque
B) horn
C) arête
D) U-shaped valley

Question 35

The Matterhorn, in the Swiss Alps, is an example of a(n) ____.

A) arête
B) tarn
C) cirque
D) horn

Question 36

In a plastically flowing alpine glacier, the ____.

A) center of the ice flows slower than the sides
B) bottom of the glacier flows the fastest
C) center of the ice flows faster than the sides
D) the middle depths of the glacier flow the slowest

Question 37

A ____ is an elongate hill of sediment, usually occurring in clusters, that was deposited and eroded by a glacier.

A) ground moraine
B) drumlin
C) kettle
D) terminal moraine

Question 38

The Pleistocene Glaciation began about ____ years ago.

A) 15,000
B) 2 million
C) 20 million
D) 250 million

Question 39

Deep, narrow valleys that were carved by glaciers and were later flooded by rising seas as the glaciers melted are called ____.

A) cirques
B) outwash plains
C) fjords
D) kettle lakes

Question 40

A relatively warm, ice-free, time between glaciations is called a(n) ____.

A) precessional cycle
B) pluvial period
C) Milankovitch cycle
D) interglacial period

Question 41

A deposit of windblown glacial silt is called ____.

A) till
B) loess
C) stratified drift
D) tillite

Question 42

Pressure from the weight of overlying ice favors melting at the base.

Question 43

Glaciers form U-shaped valleys.

Question 44

The waterfalls of Yosemite Valley cascade from hanging valleys.

Question 45

Much of the northern Great Plains is covered with ground moraines, loess, or outwash.

Question 46

Kames are composed of stratified drift.

Question 47

Currently, Earth has only two ice sheets.

Question 48

Rates of glacial movement depend entirely on air temperature.

Question 49

A moraine at the end of a glacier that is neither advancing nor retreating is called a lateral moraine.

Question 50

Ice is so much more viscous than water that it sorts particles into various sizes.

Question 51

Glacial striations can be used to map the flow direction of glaciers.

Question 52

During a glaciation ____.

A) all of the continental land is covered by ice, but the oceans remain ice-free
B) ice covers all of Earth's land and water
C) the high latitudes are ice covered, but there are no glaciers exist near the equator
D) alpine glaciers descend into lowlands, and continental glaciers spread over the high-latitude continents

Question 53

The Snowball Earth hypothesis suggests that during the late-Precambrian, ice completely covered all of the continents, and the world's oceans froze over.

Question 54

Precession relates to the shape of Earth's orbit around the Sun.

Question 55

The Great Salt Lake is a remnant of the once-larger ____ lake called Lake Bonneville.

A) kettle
B) pluvial
C) cirque
D) fjord

Question 56

Although many of Earth's alpine glaciers have been rapidly shrinking in recent years, the Antarctic Ice Sheet has remained stable, losing no ice mass.

Question 57

Alpine glaciers are found on every continent on Earth.

Question 58

Glacial ice forms in the zone of ablation.

Question 59

During the maximum extent of Pleistocene glaciers around 18,000 years ago, global sea level was about ____ than present levels.

A) 130 meters lower
B) 120 meters lower
C) 20 meters higher
D) 10 meters higher

Question 60

Cycles identified by Milutin Milanković are caused by ____.

A) changes in Earth's tides
B) increased sunspot activity
C) variations in Earth's orbit and spin axis
D) increased volcanic activity

Question 61

Describe the two categories of drift.

Question 62

Describe in detail the ice shelf that broke away from Antarctic between 2000 and 2002.

Question 63

Compare and contrast the glacial movements of the coastal ranges of southeast Alaska with the interior of Alaska.

Question 64

Describe the rate of glacial movement, include the factors that influence the rate.

Question 65

Describe the growth of an alpine glacier.

Question 66

Describe the two mechanisms by which glaciers move.

Question 67

Explain where alpine glaciers exist and do not exist.

Question 68

Why is firn important to mountaineers?

Question 69

What equipment is needed to climb into a crevasse?

Question 70

Describe the two environments in which glaciers form.

Question 71

List the location of Earth's two ice sheets and describe how much fresh water is in them.

Question 72

What are crevasses and how do they form?

Question 73

Compare and contrast basal slip and plastic flow.

Question 74

Compare and contrast the Greenland and Antarctic ice sheets.

Question 75

How are paternoster lakes formed?

Question 76

Describe the geographic extent of the most recent continental glacier in North America.

Question 77

Describe the shape of a valley that is carved by a stream and the shape of a valley that is carved by a glacier.

Question 78

Describe the sights and sounds inside of a crevasse.

Question 79

What are horns and where are the most famous ones located?

Question 80

During the past 1 billion years, how many major glaciations occurred during that time and about how long did they last?