1.c Types of Glaciers + movement

Question 1

What are the two different types of glaciers?

Answer 1

Temperate ( warm based)

Polar (cold based)

Question 2

what is the pressure melting point?

Answer 2

The temperature at which the ice is on the verge of melting

Question 3

Temperature profile/rate of accumulation / ablation of TEMPERATE

Answer 3

T = 0 degrees base
-10 degrees surface

Accumulation =greater in winter
Ablation = rapid in summer

Question 4

Temperature profile/rate of accumulation / ablation of polar

Answer 4

T = all times well below 0 degrees
accumulation = rates are low
Ablation = rates are low

Question 5

PMP of temperate glaciers

Answer 5

At or above PMP due to warmer atmospheric pressure so melts at base.

Question 6

PMP of Polar glaciers

Answer 6

Below PMP so no melting as ice stays cold and stays frozen to bedrock all year

Question 7

Location of temperate and polar glaciers

Answer 7

Temperate = higher altitudes
Polar - higher latitudes

Question 8

What is the average rate of ice movement per year?

Answer 8

3m-300m per annum

Question 9

What are the 6 factors that impact how a glacier moves?

Answer 9

1- gravity
2- gradient - steeper = faster
3- thickness of ice
4- internal temperature
5- glacial budget
6- bedrock geology

Question 10

What are the two main types of glacial movement ?

Answer 10

Internal deformation and Basal sliding

Question 11

What movement is for temperate and polar glaciers?

Answer 11

Polar = Internal deformation
Temperate = basal sliding

Question 12

What is Basal Sliding?

Answer 12

sliding of a temperate glacier over bedrock due to more meltwater lubricating easier movement

Question 13

What is the basal slip in basal sliding ?

Answer 13

lubricating effect of meltwater,making easier to move

Question 14

What is the enhanced basal creep in basal sliding ?

Answer 14

obstacle in glacier path increases pressure → begins to behave like a plastic flowing around an obstacle.

Question 15

What is the regelation flow ?

Answer 15

An obstacle in the way causing the ice to melt to get over the obstacle then refreezes → the latent heat released by refreezing conducts back and leads to this melting earlier.

Question 16

What is slippage?

Answer 16

circular motion that can cause ice to move away from the back wall of a hollow

Question 17

What is creep?

Answer 17

slow downward movement of lose rock and soil down a slope

Question 18

what is bed deformation?

Answer 18

movement of soft sediment beneath a glacier.

Question 19

What is internal deformation?

Answer 19

In very cold climates cold based glaciers are frozen to bedrock so no friction and no increase in pressure
As a result, Ice crystals in the ice move in direction of the movement
They slide past each other leading to crevasses.

Question 20

In internal deformation what parts of the glacier moves faster?

Answer 20

The surface of the glacier moves faster than the base. → base frozen to bedrock
The middle of the glacier moves faster than the sides. → as attached on each side / middle furthest away than anything it’s frozen too.

Question 21

What is inter granular flow ?

Answer 21

individual ice crystals move relative to eachother

Question 22

What is Laminar flow?

Answer 22

individual ice crystals move along layers within the glacier.

Question 23

What is a serac?

Answer 23

tower of ice which forms in the middle of a crevasse

Question 24

What is a crevasse ?

Answer 24

A deep wedge in the glacial ice

Question 25

What is extensional flow?

Answer 25

where the gradient becomes steeper making the ice to move faster.

This stretches the ice mass –> makes it thinner –> forms crevasses