Cryosphere 2 -Ice

Question 1

Glacial deposition

Answer 1

As glaciers move along the landscape, they erode the underlying bedrock and accumulate material that falls on them.

Question 2

Where deposition occurs in glacier ablation areas

Answer 2

at the base and margins of the glacier

Question 3

Ablation

Answer 3

below the equilibrium line in a glaceir

Question 4

Till

Answer 4

Poorly sorted sediment left behind by glaciers.

Question 5

If till is reworked by meltwater beyond the terminus of a glacier, it can be redeposited by

Answer 5

outwash

Question 6

Moraines

Answer 6

Ridged accumulations of till that form as glacier advances and retreats

Question 7

Types of moraines

Answer 7

Lateral, medial, and end moraines

Question 8

Lateral Moraines

Answer 8

Form at the sides of the glacier (types of end moraines)

Question 9

Medial moraines

Answer 9

Middle moraines forming when two glaciers meet

Question 10

Terminal moraines

Answer 10

End moraines that show the extent of the glacier before it recedes

Question 11

Drumlins

Answer 11

elongated and asymmetrical hills that form near the terminus of glaciers by the action of glacial ice on underlying unconsolidated sediments.

Question 12

The ice flow direction on a drumlin is from the ___ side toward the ___ side of the drumlin.

Answer 12

steep to shallow

Question 13

Eskers

Answer 13

Ridges of well sorted sand and gravel formed from rivers flowing beneath glacial ice

Question 14

Kettles

Answer 14

closed basins formed by the melting away of a mass (block) of underlying glacial ice

Question 15

Kames

Answer 15

piles of sand and gravel that were accumulated in streams and lakes on top of glacial ice, and is deposited on the land surface when the glacier retreats

Question 16

Proglacial lakes

Answer 16

lakes formed on the top of the ice sheet and at the margin while the ice age was ending

Question 17

Permafrost

Answer 17

a permanently frozen ground that contains ice that froze during past glaciations

Question 18

Permafrost is thickest in:

Answer 18

where they were exposed to long periods of colder air temperatures

Question 19

How permafrost is a carbon sink:

Answer 19

Prevents carbon from being degraded by microbes that would form greenhouse gases

Question 20

Active layer of permafrost

Answer 20

A layer on top of permafrost that melts every summer

Question 21

Pattered ground

Answer 21

Cyclical freezing and thawing cycles each year lead to the formation of patterned ground, and to frost heaving called pingos.

Question 22

Pingos

Answer 22

small hills formed through frost heaving

Question 23

Sea ice forms when

Answer 23

air temperature falls below the freezing point of seawater (-2 degrees)

Question 24

Frazil ice

Answer 24

Small needles of frozen ice that initially form as sea water freezes.

Question 25

Formation of frazil ice into ice sheets

Answer 25

1. small needles of ice form as sea ice freezes
2. frazil ice freezes together to form ice sheets
3. subsequent freezing at the base adds thickness

Question 26

Sea ice can be __ or ___.

Answer 26

annual or perennial (lasts several years)

Question 27

Arctic sea ice is highly sensitive to ____.

Answer 27

climate

Question 28

Sea ice typically moves ____ a day

Answer 28

several km

Question 29

Leads

Answer 29

When ice cracks forming leads to open water. When leads freeze, they form mosaic patterns.

Question 30

Pressure ridges

Answer 30

produced by the convergence of ice masses

Question 31

How sea ice drives ocean circulation

Answer 31

1. sea ice freezes leaving salt which makes the ocean more saline (concentrated)
2. This water is colder and denser making it sink (flow downward)

Question 32

How sea ice effects climate

Answer 32

1. isolating ocean water from the atmosphere which prevents heat exchange
2. high albedo causing it to reflect light and heat
3. it contributes to the temperature gradient between the poles and equator driving atmospheric circulation (wind)