Glaciation

Question 1

What is the cryosphere

Answer 1

Frozen landscapes

Question 2

What are the deposited glacial landforms?

Answer 2

Till
Erratics
Crag-and-tails
Moraines
Drumlins

Question 3

What are the 4 types of moraines and where do they form?

Answer 3

Medial - Forms in the middle of two glaciers
Lateral - Forms along the sides of glaciers
Terminal - Forms in front of a glacier when it stops advancing
Recessional - Marks an interruption to the glacier’s retreat

Question 4

What are the 3 types of glacial erosion?

Answer 4

Plucking
Freeze-thaw
Abrasion

Question 5

Describe the location and formation of drumlins:

Answer 5

Found in large swarms on valley floors in lowland areas.
Moraine material formed into low egg-shaped hills.
Blunt and steep at the stoss end
Gentle and wide at the lee end (Down-glacier end).
Formed by the streamlined movement of glacial ice sheets across rock debris, or till.

Question 6

What is till?

Answer 6

Glacially transported material, usually made up of sand, mud and gravel-sized material deposited directly from glacial ice.

Question 7

What are moraines made of?

Answer 7

The build-up of till.

Question 8

What are the 5 types of glacial movement

Answer 8

Internal deformation
Basal Slippage
Rotational Flow
Extensional Flow
Compressional Flow

Question 9

How does internal deformation work

Answer 9

individual particles of ice melt around their edges allowing air to escape
one by one the particles slip forward on the thin film of water and immediately refreeze, causing momentary movement

Question 10

internal deformation characteristics

Answer 10

Commonly at the base of the glacier
Very slow movement.​

Ice is polycrystalline.​

Individual crystals move.​

Base of crystal stays still and top moves downhill under gravity.​

Creates crevasses on glacier surface

Question 11

what is basal slippage

Answer 11

The sliding of a glacier over bedrock, a process usually facilitated by the lubricating effect of meltwater.
Occurs when glacier slides over surrounding sediment and rocks.​

Question 12

what is rotational flow

Answer 12

This is a downhill flow of ice which, like a landslide, pivots around a point producing a rotational movement.​

Question 13

describe the process of extensional flow

Answer 13

Extensional flow = gradient increases – velocity increases – lower valley ice moves faster than upper valley (ice runs away with itself) – ice thins and spreads out = cracks/crevasses​

Question 14

describe the process of compressional flow

Answer 14

Compressional flow – gradient reduced – velocity reduced – upper floor ice is pushing on lower valley ice.

Question 15

what does the rate of movement depend on?

Answer 15

Gravity – steeper the gradient, the greater the pull​

Friction – Less friction, more movement​

Meltwater – Lubrication of the ground allowing slip​

Ice temperature ​

Ice mass – The heavier it is, the more energy it has to move​

Question 16

What is mass balance?

Answer 16

The rate of accumulation against the rate of ablation

Question 17

How is glacial budget calculated

Answer 17

rate of accumulation - rate of ablation over the course of the year

Question 18

What is a cold-based glacier and what kind of movement occurs here

Answer 18

A glacier in which there is a lack of water.
This leads to much slower movement and thus less erosion.
Internal deformation occurs here more prominently

Question 19

what is a warm-based glacier and what kind of movement occurs here

Answer 19

A glacier with water at its base, acting as a lubricant on the rock surface. This allows for basal slippage to occur, which is faster and causes more erosion

Question 20

What is the equilibrium line?

Answer 20

Where the rate of accumulation matches the rate of ablation, so there is no increase or decrease in mass

Question 21

What are the inputs in a glacial system

Answer 21

Snowfall

avalanches

Question 22

What are the outputs

Answer 22

Melting
evaporation
sublimation
iceberg calving