Chapter 18 Glaciers And Glaciation

Front 1

Compared with the amount of ice that existed during the last glacial maximum, how much exists today?

Back 1

1/3 as much

Front 2

You are working in a field area that you think at one time contained valley glaciers. What evidence would you look for to determine this?

Back 2

You would look for rounded, U-shaped valleys.

Front 3

During the last glacial maximum, the position of sea level occurred at what elevation relative to its position today?

Back 3

At the last glacial maximum, sea level was about 100 meters (~300 feet) lower than it is today.

Front 4

Which part of a glacier will see the build-up of ice and snow over the course of a full year?

Back 4

Zone of accumulation

Front 5

How does a glacier lose ice through sublimation?

Back 5

Ice changes from solid to gas.

Front 6

What scenario describes a glacial advance?

Back 6

More ice and snow accumulates than melts each year.

Front 7

During a glacial retreat, a glacier will flow _____ while the terminus moves _____.

Back 7

forward; backward

Front 8

Which type of glacial movement is circled

Back 8

basal sliding

Front 9

Which type of glacial movement will be responsible for the greatest amount of glacial flow?

Back 9

Internal Flow

Front 10

Explain why post A has moved farther than posts B and C

Back 10

Ice in the center of a glacier has the least friction with the surrounding bedrock and can flow faster.

Front 11

A __________ is defined as a chain of glacial lakes where each lake flows into the next.

Back 11

pater noster lake

Front 12

What glacial feature is circled in Figure 1?

Back 12

arête

(This arête formed between two U-shaped glacial valleys)

Front 13

What glacial feature is circled in Figure 2?

Back 13

horn

(Horns are peaks that have been eroded on all sides by glaciers)

Front 14

What is the best way to describe the shape of a glacial valley?

Back 14

U-shaped

(U-shaped glacial valleys are very characteristic on an alpine landscape)

Front 15

Which two regions currently contain the world’s last remaining ice sheets?

Back 15

Antarctica and Greenland

Front 16

When was the last time North America had major ice sheets

Back 16

18,000 years ago

Front 17

Which landform marks the furthest extent of an advancing glacier?

Back 17

terminal moraine

Front 18

What glacial landform is visible in Figure 1?

Back 18

dumlin

Front 19

What feature is responsible for creating eskers?

Back 19

streams that flowed below, in, or on the glacier

Front 20

Which orbital effect describes how the shape of Earth’s orbit around the Sun will change over time?

Back 20

Which orbital effect describes how the shape of Earth’s orbit around the Sun will change over time?

Front 21

What is the critical latitude for incoming solar radiation, which could affect the formation of ice sheets?

Back 21

65° N

Front 22

What effect will an increased angle of tilt have on the Earth’s climate?

Back 22

warmer summers and colder winters

Front 23

Which of the following scenarios will have the greatest chance of triggering an ice age?

Back 23

eccentricity, obliquity, and precession overlapping to provide the least amount of solar radiation

Front 24

________ are stratified sands and gravels carried away from the glacial terminus by meltwater.

Back 24

outwash

Front 25

What is a pluvial lake?

Back 25

A lake that fills due to increased precipitation in a cooler, wetter climate

Front 26

Which part of a glacier is responsible for abrasion and plucking?

Back 26

Basal Sliding Zone

Front 27

________ is the name for glacial deposits that have been lithified into a sedimentary rock.

Back 27

Tillite

Front 28

Which glacial erosion feature will likely contain a waterfall today?

Back 28

Hanging valley