Glaciated Landscapes Unit 2

Question 1

What is the cryosphere?

Answer 1

The parts of the Earth’s crust and atmosphere that are below 0˚C for at least part of each year.

Question 2

What are the two main categories of ice masses?

Answer 2

• Constrained ice masses
• Unconstrained ice masses

Question 3

What factors control the morphology of ice masses?

Answer 3

• Climate
• Topography

Question 4

Define unconstrained ice masses.

Answer 4

Ice masses with a morphology and flow pattern that is largely independent of underlying topography.

Question 5

Define constrained ice masses.

Answer 5

Ice masses with a morphology and flow pattern that is strongly dependent on underlying topography.

Question 6

What is the primary distinction between cold-based and warm-based glaciers?

Answer 6

Cold-based glaciers are frozen to the bedrock, while warm-based glaciers have liquid water at their base.

Question 7

Where are cold-based glaciers typically found?

Answer 7

High latitude locations such as Antarctica and Greenland.

Question 8

What is pressure melting?

Answer 8

Melting of ice at temperatures below 0˚C due to the pressure from the weight of overlying glacial ice.

Question 9

What is regelation?

Answer 9

The process where ice melts under pressure and refreezes when the pressure is reduced.

Question 10

What are the two specific processes of basal sliding?

Answer 10

• Enhanced Basal Creep
• Regelation Slip

Question 11

What is internal deformation in glaciers?

Answer 11

The response of individual grains of ice within the glacier to the overlying pressure.

Question 12

What are the two mechanisms that cause internal deformation?

Answer 12

• Intergranular Flow
• Laminar Flow

Question 13

What is the typical range of glacial movement in meters per year?

Answer 13

3 to 300 meters per year.

Question 14

What is the primary difference in movement between warm-based and cold-based glaciers?

Answer 14

Warm-based glaciers generally have a greater overall velocity of ice movement than cold-based glaciers.

Question 15

What happens during a glacial surge?

Answer 15

A glacier’s snout advances up to 1000 times faster than normal due to changes in sub-glacial meltwater flow.

Question 16

Fill in the blank: The __________ builds up underneath the glaciers during a phase of normal glacier flow.

Answer 16

WATER

Question 17

Fill in the blank: The subglacial __________ channels are closed during winter, increasing ice accumulation.

Answer 17

MELTWATER

Question 18

True or False: Polar glaciers can move by basal sliding.

Answer 18

False

Question 19

What is the pressure melting point?

Answer 19

The temperature below 0˚C at which ice can melt due to the pressure of overlying glacier ice.

Question 20

What is an ice sheet?

Answer 20

Complete submergence of regional topography, forming a gently sloping dome of ice several kilometres thick in the center.
Approximately 50000km2
Unconstrained
Example: Antarctic Ice Sheet

Question 21

What is an ice cap?

Answer 21

A smaller version of an ice sheet that occupies upland areas.
Less than 50000km2
Unconstrained
Example: Austfonna Ice Cap in Svalbard Archipelago in Norway

Question 22

What is a valley glacier?

Answer 22

A glacier confined between valley walls, terminating in a narrow tongue, forms from ice caps/sheets or cirques. May terminate in the sea as a tide water glacier.
3-1500km2
Constrained by valley walls
Example: The Fraser Glacier - Alaska

Question 23

What is a piedmont glacier?

Answer 23

A valley glacier that extends beyond the end of a mountain valley into a flatter area and spreads out as a fan.
3-1000km2
Constrained
Example: Malaspina Glacier in SE Alaska, USA

Question 24

What is the typical size range of an ice field?

Answer 24

10 – 10,000 km².

Question 25

What is the typical size range of a cirque glacier?

Answer 25

0.5 – 8 km².

Question 26

Fill in the blank: Warm based glaciers are found outside of the polar region, usually in high altitude areas where the temperature fluctuates __________.

Answer 26

above and below melting point

Question 27

What is the effect of slope angle on glacier movement?

Answer 27

Increased slope angle accelerates ice movement due to higher forces of gravity.

Question 28

What is the role of geothermal energy in warm-based glaciers?

Answer 28

It contributes to melting at the base of the glacier.

Question 29

Define ‘crevasses’.

Answer 29

Fractures in the ice that occur when ice moves on a steep slope and cannot deform quickly enough.

Question 30

What is the average temperature range at the surface of cold-based glaciers?

Answer 30

-20˚C to -30˚C.

Question 31

What is an ice field?

Answer 31

Ice covering an upland area but not thick enough to bury the topography. Many do not extend beyond the highland source.
10-10000km2
Constrained
Example: James Ross Island on the NE Antarctic Peninsula

Question 32

What is a cirque glacier?

Answer 32

Smaller glacier occupying a hollow o the mountain side- it carved out a corrie or cirque; a small version is known as a niche glacier.
0.5-8km2
Constrained
Example: Eel Glacier on Mount Anderson (Olympic National Park, Washington, USA)

Question 33

What is the pressure required for the ice to melt in a glacier with pressure melting?

Answer 33

As pressure increases the temperature at which ice melts will fall below 0C at a rate of 1C for every 100Kg/cm2 of pressure.
Eg: if the pressure at the base of a glacier is 400Kg/cm2 then ice with a temp of warmer than -4C will melt