Chapter 18 Flashcards Preview

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Flashcards in Chapter 18 Deck (15):
1

Glacier

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

2

Two basic cycles of Glaciers

Hydrologic cycle
Rock cycle

3

Valley Glaciers

Glaciers that exist in valleys of mountainous areas

4

ice sheets

exist on a larger scale than valley glaciers

5

sea ice

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

6

Glaciers form on land

-Greenland in northern hem
-Antarctica in southern hem

7

ice shelves

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

8

ice caps

cover some uplands and plateaus

9

outlet glaciers

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

10

Piedmont glaciers

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

11

snowline

snow above this line does not melt in the summer

12

How glaciers form

-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

13

Glacial ice moves as

flow

14

Plastic flow of glaciers

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

15

Basal slip

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