MG CH 15

25 July 2022
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30 test answers

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question
Which of the following responses best defines the movement of ice within a glacier?
answer
Glacial movement is always in a downslope direction
question
The terminus of a glacier will advance when which of the following conditions is met?
answer
Accumulation of snow is greater than wastage
question
Which of the following best describes the position and/or migration of the snowline on an active glacier?
answer
The snowline moves downslope when the glacier is advancing
question
Working in a mountain valley that contains an alpine glacier, you discover a series of end moraines in the valley. As you move up toward the glacier, what conclusions can you expect to make about the moraines?
answer
The moraines get younger as you get closer to the glacier
question
During the Cold War, a B-52 bomber accidentally dropped an unarmed nuclear device on the Greenland Ice Sheet. Upon returning to the drop zone many years later, the device had gone missing. As a glaciologist on the project, where should you look for the missing device?
answer
To find it you should go downslope from the drop zone, in the direction of ice flow
question
Where do glaciers form?
answer
In places where more snow falls in the winter than melts away in the summer
question
What is the snowline?
answer
The elevation above which snow persists throughout the yar
question
What is the zone of wastage?
answer
The part of a glacier where snow melting exceeds snow accumulation
question
Under what conditions will the front of a glacier remain stationary?
answer
Glacial fronts remain stationary when melting and snow accumulation are equal
question
What is an end moraine?
answer
A ridge of debris deposited at the end of a glacier
question
How does an end moraine form?
answer
Pieces of rock are transported to the front of a glacier as ice within the glacier moves
question
Will plucking occur if a glacier is NOT advancing?
answer
Yes, because glacial ice is still moving inside the glacier even if the glacier's front is not advancing
question
A ___ is defined as a chain of glacial lakes where each lake flows into the next.
answer
Pater noster lake
question
What is the best way to describe the shape of a glacial valley?
answer
U-Shaped
question
What is the name for an isolated boulder of unexpected rock type that has been transported by a glacier and stranded after the ice melts?
answer
erratic
question
What causes a crevasse to form?
answer
When ice flows around a bend or over an obstacle, it is stretched and torn, causing large cracks to form
question
What causes streams that emerge from glaciers to be milk-colored?
answer
The presence of finely ground sediment called rock flour in the meltwater
question
What shape is a glacial trough?
answer
U-Shaped
question
Most modern glaciers are ___.
answer
Retreating
question
Which two regions currently contain the world's last remaining ice sheets?
answer
Antartica and Greenland
question
When was the last time North America had major ice sheets?
answer
18,000 years ago
question
Which landform marks the furthest extent of an advancing glacier?
answer
terminal moraine
question
What feature is responsible for creating eskers?
answer
streams that flowed below, in, or on the glacier
question
Which orbital effect describes how the shape of Earth's orbit around the Sun will change over time?
answer
eccentricity
question
What is the critical latitude for incoming solar radiation, which could affect the formation of ice sheets?
answer
65 degrees N
question
How many years does one complete cycle of precession take?
answer
26,000 years
question
What effect will an increased angle of tilt have on the Earth's climate?
answer
warmer summers and colder winters
question
Which of the following scenarios will have the greatest chance of triggering an ice age?
answer
eccentricity, obliquity, and precession overlapping to provide the least amount of solar radiation
question
A(n)___ would logically be situated next to a large end moraine or terminal moraine.
answer
outwash plain
question
What type of moraine is formed by the merging of two lateral moraines at a junction of two valley glaciers?
answer
medial