Glaciers

Question 0

Glaciers: Can be

Answer 0

Valley glaciers or ice sheets / ice caps.

Question 1

A glacier is like a

Answer 1

River of ice, gradually moving downhill.

Question 2

Glaciers: Must be on

Answer 2

Land throughout the year.

Question 3

Glaciers: Occur in

Answer 3

Polar regions and mountain areas, produced by snowfall and low temperatures.

Question 4

Ice sheets: In

Answer 4

Polar regions, the ice is continent-sized ice sheets.

Question 5

Ice sheets: 95% of the plants ice is

Answer 5

On Greenland and Antartica.

Question 6

Ice caps:

Answer 6

Smaller ice sheets in mountain regions.

Question 7

Glacier movement: Downhill flow by

Answer 7

Force of gravity.

Question 8

Glacier movement: Greater thickness of ice &

Answer 8

Steeper gradient = faster flow.

Question 9

Glacier movement: Ice crystals can melt then

Answer 9

Recrystallise further downslope, resulting in the glacier moving downhill.

Question 10

Glacier movement: Repeated melting and

Answer 10

Freezing at base helps the glacier to slide downhill.

Question 11

Glacier movement: Flow is achieved by

Answer 11

Movement within individual ice crystals.

Question 12

Glacier movement: Increasing snow adds

Answer 12

Pressure to a glacier, resulting in deformation/creep along internal planes within ice crystals.

Question 13

Glacier movement: Over time, crystals tend to

Answer 13

Orientate themselves in a downslope direction, favouring further flow.

Question 14

Valley glaciers: Form in

Answer 14

Mountain regions.

Question 15

Valley glaciers: Are ribbons of

Answer 15

Ice, confined by the surrounding topography, which controls the shape and direction of movement.

Question 16

Valley glaciers: Approx

Answer 16

1km - 2km long with areas of less than several km.

Question 17

Valley glaciers: Large glaciers may

Answer 17

Move the the valley floors to form ice fields.

Question 18

Accumulation:

Answer 18

The addition of mass to a glacier.

Question 19

Ablation:

Answer 19

The loss of mass from a glacier.

Question 20

Main output:

Answer 20

Meltwater, from the melting of ice.

Question 21

Main input:

Answer 21

Snow, which becomes glacier ice.

Question 22

Mass balance: A measure of

Answer 22

Change in the total mass of a glacier during a year.

Question 23

Mass balance: Positive -

Answer 23

Results in the front end advancing.

Question 24

Mass balance: Negative -

Answer 24

Results in the retreat of a glacier.

Question 25

Non-equilibrium behaviour: Can result from a

Answer 25

Build up of water at base, leading to periods of enhanced glacial sliding.

Question 26

Non-equilibrium behaviour: Surge -

Answer 26

Unusually rapid movement where the glacier can advance by several km and the flow can be 100x greater than normal.

Question 27

Non-equilibrium behaviour: A surge is usually

Answer 27

Preceded by a period of stagnation in the lowest part of the glacier.

Question 28

Equilibrium line: Mass loss =

Answer 28

Mass gain.

Question 29

Equilibrium line: Zone of accumulation -

Answer 29

The upper zone, area of mass gain.

Question 30

Equilibrium line: Zone of ablation -

Answer 30

Lower zone, area of mass loss.

Question 31

Equilibrium line: Higher with

Answer 31

Net loss, lower with net gain.