Deck 14: Glaciers and Glaciation

Question 1

A glacier forms when ____.

A)snow accumulates to form ice, and the ice mass begins to flow under its own weight
B)temperatures do not rise above freezing
C)snow moves downslope under the influence of gravity
D)meltwater at the base of a snow mass contributes to downslope flow
E)a thick layer of ice is present

Answer 1

snow accumulates to form ice, and the ice mass begins to flow under its own weight

Question 2

A glacier that is unconfined by topography and has tributaries is a(n)____.

A)ice cap
B)tributary glacier
C)continental glacier
D)valley glacier
E)alpine glacier

Answer 2

valley glacier

Question 3

The most important process by which glaciers move is ____.

A)basal slip
B)plastic flow
C)elastic flow
D)creep
E)brittle flow

Answer 3

plastic flow

Question 4

The three stages involved in the formation of glacial ice are, in order, ____, ____, and ____.

A)snowfall; firn; glacial ice
B)accumulation; firn; wastage
C)snowfall; sublimation; slip
D)snowfall; sublimation; glacial ice
E)accumulation; firn; slip

Question 5

Suppose that glacial ice were a rock. What type of rock would it be?

A)igneous only
B)sedimentary only
C)metamorphic only
D)Glacial ice cannot be a rock.
E)A combination of sedimentary and metamorphic

Question 6

How much of Earth's surface is covered by glaciers?

A)1%
B)2%
C)5%
D)10%
E)20%

Question 7

Which statement about valley glaciers is true?

A)They tend to flow faster than continental glaciers.
B)They carry sediments only in the lower part of the ice.
C)They are confined to high latitude regions.
D)They are not controlled by land topography.
E)They are much larger than continental glaciers.

Question 8

Glacial striations, roche moutonées, and drumlins allow scientists to identify the direction of glacial movement.

Question 9

The majority of glaciers on Earth are melting in response to warmer temperatures.

Question 10

According to the Milankovitch theory, variations in Earth's orbit and axial tilt can trigger long-term climatic changes and prompt the start and end of ice ages.

Question 11

Continental glaciers generally flow on the order of centimeters to meters per day.

Question 12

Sea level has fallen dramatically since the Pleistocene Epoch.

Question 13

In the process of sublimation, ____.

A)ice melts to become liquid water, which then evaporates
B)fresh snow becomes firn and then glacial ice
C)ice changes directly into water vapor
D)white ice becomes denser so that blue wavelengths are transmitted and scattered and the ice appears blue
E)small crystals of ice become larger

Question 14

Basal slip becomes a more important means of glacier movement in warmer months when more meltwater collects at a glacier's base.

Question 15

When did the Pleistocene Ice Age end?

A)It is still ongoing.
B)300 years ago
C)1,500 years ago
D)11,700 years ago
E)2.6 million years ago..

Question 16

Medial moraines demarcate the various tributaries of a glacier and form when two end moraines merge.

Question 17

There is good evidence that variation in solar energy, as evinced by sunspot activity cycles, is responsible for short-term climatic variations.

Question 18

Glaciers are geologically important because they erode, transport, and deposit so much material.

Question 19

Which is the only continent that does not presently have glaciers?

A)South America
B)North America
C)Africa
D)Europe
E)Australia

Question 20

End moraines continue to grow as long as the ice front remains stationary.

Question 21

A glaciers budget is balanced when ____.

A)additions to the zone of accumulation equal losses in the zone of wastage
B)losses in the zone of accumulation equal additions to the zone of wastage
C)the zone of accumulation receives more input than the zone of wastage
D)the zone of wastage does not lose material
E)the firn limit moves down in the summer and up in the winter

Question 22

Short-term climatic changes like the Little Ice Age are poorly understood. One hypothesis for why short-term climatic events occur is ____.

A)plate tectonic activity
B)orbital eccentricity
C)axial tilt
D)precession of the equinoxes
E)variations in solar radiation

Question 23

What happens to ice movement within a glacier when the glacier is retreating?

A)The ice flows uphill.
B)The ice flows downhill.
C)The ice flow spreads out laterally.
D)The ice no longer flows.
E)The ice flows downhill in the zone of accumulation and uphill in the zone of wastage.

Question 24

Orbital eccentricity refers to ____.

A)the need to add a "leap day" every four years
B)variation in the timing of Earth's equinoxes
C)how much Earth is tilted on it's axis
D)how close Earth is to the Sun
E)how circular or elliptical Earth's orbit is

Question 25

Worldwide, the majority of glaciers are ____.

A)advancing
B)retreating
C)approaching the firn limit
D)flowing faster
E)flowing slower

Question 26

Ice Ages ____.

A)have occurred regularly through Earth's history
B)have glacial episodes separated by very short interglacial stages
C)result from declines in sea level
D)are the result of variations in the amount of solar heat received
E)occur whenever accumulation of snow exceeds wastage

Question 27

Which of the following is a depositional feature of glaciers?

A)cirque
B)arête
C)horn
D)roche moutonée
E)end moraine

Question 28

The health of a glacier and the glacial budget are determined primarily by ____.

A)comparing one glacier to others in the nearby vicinity
B)measuring the rate of glacial movement
C)the thickness of ice
D)testing the quality of its meltwater
E)the amount of snowfall and temperature

Question 29

If wastage is greater than accumulation, a glacier is said to be ____.

A)advancing
B)melting
C)surging
D)retreating
E)stable

Question 30

Mountain valleys subjected to glaciation are typically shaped like ____.

A)a semi-circle
B)the letter "V"
C)the letter "U"
D)one half of a rectangle
E)an inverted letter "V"

Question 31

What is a lake formed within a cirque?

A)arête
B)esker
C)tarn
D)fjord
E)drumlin

Question 32

A terminal moraine marks the ____.

A)fartherest a glacier can spread from side-to-side
B)location where the glacier started to form
C)farthermost point of a glacier's advance
D)location where outwash forms
E)boundary between two glaciers

Question 33

Which of the following is an erosional feature of glaciers?

A)glacial erratics
B)terminal moraines
C)drumlins
D)cirques
E)eskers

Question 34

A glacier begins to flow when the ice reaches what critical thickness?

A)5 meters
B)10 meters
C)20 meters
D)40 meters
E)100 meters

Question 35

Which type of glacial deposit was formed by running water?

A)eskers
B)drumlins
C)roche moutonées
D)varves
E)erratics

Question 36

In a cross-section of a glacier, where do the greatest flow velocities occur?

A)at the surface
B)in the few tens of meters below the surface
C)in the few tens of meters above the base
D)at the base
E)in the center of the flow

Question 37

A glacial landform produced primarily by plucking rocks on the downstream side and smoothing by the glacier on the upstream side is called a(n)____.

A)roche moutonée
B)esker
C)kame
D)terminal moraine
E)cirque

Question 38

A glacial landform that forms at the head of glacial valleys or troughs is called a(n)____.

A)roche moutonée
B)esker
C)kame
D)arête
E)cirque

Question 39

What term describes the straight scratches on rock surfaces created by glacial abrasion?

A)rock flour
B)glacial striations
C)glacial till
D)varves
E)moraines

Question 40

Glacial till is ____.

A)any sediment deposited as a result of glacial activity
B)boulders transported long distances and deposited by glaciers
C)an elongated spoon-shaped hill that has been shaped by an overriding glacier
D)unstratified sediment deposited directly by a glacier
E)a lake within an outwash plain

Question 41

In the accompanying figure, identify a drumlin, esker, kame, recessional moraine, and terminal moraine. Is this landscape more representative of continental or alpine glaciation and why?

Question 42

The climatic event that began with cooling in about AD 1300 and lasted until the middle 1800s is known as the ____________________.

Question 43

Compare and contrast valley and continental glaciers.

Question 44

An ice mass of compacted and recrystallized snow that flows under its own weight on land is called a(n)____________________.

Question 45

The zone of wastage is the portion of a glacier where ____________________ exceed ____________________.

Question 46

Name four ways wastage occurs in glaciers. Where on the glacier do each of these processes occur?

Question 47

The boundary between the zones of accumulation and wastage is called the ____________________.

Question 48

A dome-shaped ice mass of compacted and recrystallized snow that flows under its own weight and covers less than 50,000 km² of land is called a(n)____________________.

Question 49

Why do scientists study glaciers to better understand climate change? What do studies of glaciers contribute to our understanding of current climate trends?

Question 50

Is ice a mineral? Explain.

Question 51

What is a glacial erratic, and how can scientists use this feature to learn about a glacier?

Question 52

What kind of erosional landforms would you expect to find in a valley that had previously been occupied by a valley glacier?

Question 53

From a human perspective, what climatic effect of the Little Ice Age had the greatest impact?

Question 54

Extremely deep glacial valleys that formed below present day sea-level are called ___________________.

Question 55

The zone of ____________________ is the portion of a glacier where additions exceed losses.

Question 56

____________________ is a poorly sorted type of drift deposited directly by glacial ice that forms landforms like moraines.

Question 57

Finely laminated, alternating light and dark layers of sediment deposited in a glacial lake are known as glacial ____________________.

Question 58

The presence of ____________________ in the upper 40 m or so of a glacier indicates that this portion behaves not as a plastic, but as a(n)____________________ solid.