Paper 1- Section C, Uk Glacial Landscapes

Question 1

What is freeze thaw weathering

Answer 1

Water expands when it freezes, when water fills cracks in rocks if it then freezes, it expands putting pressure on the rock, eventually this will wear down the rock and causes the cracks to widen as the process repeats

Question 2

Why is freeze thaw an important process in glacial environments

Answer 2

• helps shape jagged glacial mountain landscapes
• rocks become weakened by freeze-thaw making it easier for them to be eroded by glaciers
• piles of large angular rocks called scree collect at the foot of mountains, these become powerful erosion tools when trapped under moving glaciers

Question 3

How far do glaciers move a year

Answer 3

Only a few centimetres

Question 4

What are the two main types of glacial erosion

Answer 4

Abrasion and plucking

Question 5

What is the glacial erosion abrasion

Answer 5

• sandpaper effect caused by weight of ice scouring valley floor
• abrasion leaves smooth, polished surface
• striations can be seen beneath the ice

Question 6

Describe plucking

Answer 6

• Meltwater freezes and bonds to base of glacier to the rocky surface below
• as glacier moves, any loose fragments of rocks are plucked away
• this process leaves a jagged rocky surface

Question 7

What two ways do glaciers move

Answer 7

• rotational slip and bulldozing

Question 8

What is basal slip

Answer 8

In the summer meltwater lubricates the glacier enabling it to slide downhill and the movement can be quite sudden

Question 9

What is rotational slip

Answer 9

The glacier moves out of the hollow in a circular motion called
rotational slip

Question 10

What is internal deformation

Answer 10

In the winter, the glacier becomes frozen to the rocky surface, the sheer weight of the ice and the influence of gravity cause individual ice crystals to change shape and this causes the glacier to move slowly downhill

Question 11

What is bulldozing

Answer 11

At the front of glaciers, rocks and debris are pushed downhill in a straight line

Question 12

When does deposition occur

Answer 12

Occurs when the ice melts

Question 13

Where does most of the deposition happen

Answer 13

At the front of the glacier

Question 14

What is till

Answer 14

Most material carried by glaciers in the form of unsourced mixtures is till

Question 15

In terms of deposition, what happens when the glacier retreats

Answer 15

Leaves behind a bed of broken rock fragments (till) and due to lack of water to transport, it is poorly sorted with rock fragments of all sizes

Question 16

What are moraines

Answer 16

Landforms that are left behind after a glacier melts, they are made of till

Question 17

How is lateral moraine formed

Answer 17

When an extended mound of till is deposited at the edge of a glacier and it is made up of material from the valley walls

Question 18

How are medial moraines formed

Answer 18

When an extended ridge of till is deposited in the middle of a valley and is formed when 2 glaciers join

Question 19

How are ground moraines formed

Answer 19

When till is carried underneath a glacier a ground moraine is formed and they are deposited across the valley floor

Question 20

How are terminal moraines formed

Answer 20

Made of till that was transported at the front of the glacier and is deposited at the glaciers snout

Question 21

What are corries

Answer 21

Large hollowed out depressions found on the upper slopes of glaciated valleys and are recognised by a steep back and raised lip and they may have a lake called a tarn

Question 22

How are corries formed

Answer 22

• snow accumulates in a sheltered hollow on a hillside
• processes like freeze-thaw, meltwater and slumping enlarge the hollow letting more snow collect
• gradually snow turns to ice and a small corrie is formed
• rotational slip gouges out the deep hollow
• there is less erosion at the front of the corrie as the ice is thinner and less erosive so this forms a raised lip
• a tarn may form in the bottom of the corrie

Question 23

What is an arête

Answer 23

Knife edged ridge often found at the back of a Corrie or separating two glaciated valleys, often extremely narrow

Question 24

How are pyramidal peaks formed

Answer 24

If three or more corries have formed on a mountain, erosion may lead to the formation of a single peak, a pyramidal peak

Question 25

What is a glacial trough

Answer 25

A steep-sided, wide and flat bottomed valley formed by abrasion
Most start as v-shaped river valleys, when the landscape become glaciated, individual glaciers erode them by abrasion and form u-shaped glacial troughs

Question 26

What are truncated spurs

Answer 26

Unable to flow around interlocking spurs, the glacier cuts straight through them forming steep-edged truncated spur

Question 27

What are hanging valleys

Answer 27

Smaller tributary valleys above the main glacial troughs often marked with waterfalls

Question 28

What are ribbon lakes

Answer 28

Long, narrow lakes often tens of metres deep, most result from severe erosion of the glacial trough

Question 29

What are drumlins

Answer 29

Smooth, egg-shaped hills about 10m high and several hundred metres long that are found on the floor of a glacial trough, usually have a blunt end (which faces up valley) and more pointed end (facing down valley)

Question 30

What are erratics

Answer 30

A large boulder that is out of place resting on a different type of rock probably transported by a glacier