Chapter 21

Question 1

valley glaciers

Answer 1

rivers of ice

Question 2

iceberg calving

Answer 2

when masses of ice break off glaciers at the ocean’s edge

Question 3

continental glacier

Answer 3

ice sheet that covers a large part of a continent

Question 4

ice shelves

Answer 4

thinner sheets of ice

Question 5

ice caps

Answer 5

the masses of ice that cover the Earth’s North and South pole

Question 6

what are the two types of glaciers?

Answer 6

valley glaciers and continental glaciers

Question 7

snow line

Answer 7

the elevation above which snow does not completey melt in the summer

Question 8

accumulation

Answer 8

the amount of ice added to a glacier annually

Question 9

present and past distribution of glaciers

Answer 9

Today, 10%
20,000 years ago, 30%
700 million years ago, 100%

Question 10

geologic record of ice sheets

Answer 10

40 Ma - Recent ice age
330-250 Ma - permian ice age
700 Ma - snowball earth

Question 11

How do glaciers form? in terms of layers and density

Answer 11

snow - .05-.07
granular ice - .1-.4
firn - .4-.8
glacial ice - .8-.9

Question 12

equilibrium line altitude

Answer 12

transition between snow and glacial ice

Question 13

how fast do glaciers move on average?

Answer 13

3-300 m/yr

Question 14

what is the record movement of a glacier?

Answer 14

100 ft/day

Question 15

ablation

Answer 15

total amount of ice a glacier loses annually

Question 16

mechanisms responsible for ablation (4)

Answer 16

melting
iceberg calving
sublimation
wind erosion

Question 17

sublimation

Answer 17

H2O goes from ice to vapor, skipping liquid form

Question 18

processes of glacial erosion

Answer 18

abrasion (~25%)
plucking (~75%)
other (kelleys island grooves)

Question 19

abrasion

Answer 19

particles in the glacier “sand” the surface below

-can form striation

Question 20

plucking

Answer 20

• ice plucks rock fragments, producing a rough surface

- increase pressure, ice melts to flow around obstruction and freezes on the other side, plucking rock with it

Question 21

erosional landforms (3)

Answer 21

u-shaped valleys
cirques
fjords

Question 22

u-shaped valleys

Answer 22

steep mountain sides with hanging valleys

Question 23

cirque

Answer 23

nearly vertical walls with a flat base

Question 24

fjord

Answer 24

u-shaped valley that is the arm of the sea

Question 25

glacial deposits and landforms (5)

Answer 25

drift
till
drumlins
esker
nested moraine

Question 26

drift

Answer 26

material of glacial origin found anywhere on land or beneath the ocean

Question 27

till

Answer 27

unsorted glacial sediment

Question 28

drumlins

Answer 28

sub-marine shaped hills that form from warm-based ice sheets

Question 29

esker

Answer 29

stream channel

Question 30

nested moraines

Answer 30

when glaciers remain still for a long time

Question 31

warm-based glacier

Answer 31

not frozen to landmass

Question 32

cold-based glacier

Answer 32

base frozen to landmass