Chapter 18

Question 1

Glacier

Answer 1

thick mass of ice that forms over hundreds and thousands of years by accumulation, compaction, and recrystallization of snow

Question 2

Two basic cycles of Glaciers

Answer 2

Hydrologic cycle

Rock cycle

Question 3

Valley Glaciers

Answer 3

Glaciers that exist in valleys of mountainous areas

Question 4

ice sheets

Answer 4

exist on a larger scale than valley glaciers

Question 5

sea ice

Answer 5

frozen sea water
up to 4m thick
Covers Arctic Ocean rather than glacial ice

Question 6

Glaciers form on land

Answer 6

• Greenland in northern hem

- Antarctica in southern hem

Question 7

ice shelves

Answer 7

glacial ice flows out to sea

• In shallow water ice touches bottom
• deep water ice shelf floats
• Thickest on landward side and thin seaward
• Breakup of ice shelves attributed to regional global warming

Question 8

ice caps

Answer 8

cover some uplands and plateaus

Question 9

outlet glaciers

Answer 9

ice caps and ice sheets feed them, tongues of ice extending outward from the large masses

Question 10

Piedmont glaciers

Answer 10

form when one or more alpine glacier emerges from the valley and spreads out in a broad lobe

Question 11

snowline

Answer 11

snow above this line does not melt in the summer

Question 12

How glaciers form

Answer 12

• air is forced out
• snow is recrystallized into a much denser mass of small grains (firn)
• Once thickness of ice and snow exceeds 50 meters, firm fuses into a solid mass of interlocking ice crystals-glacial ice

Question 13

Glacial ice moves as

Answer 13

flow

Question 14

Plastic flow of glaciers

Answer 14

involves movement within the ice; under pressure ice behaves as plastic material

Question 15

Basal slip

Answer 15

entire ice mass slides along the ground, meltwater acts as lubricant