6.1: The distinctive landforms of glacial erosion

Question 1

What is the most important factor that effects the efficiency of a glaciers erosion?

Answer 1

the glacier itself - its size, which determines ice thickness and thermal regime

Question 2

Which type of glacier erodes faster?
Warm based or cold based?

why is that?

Answer 2

1. warm based

• meltwater and abandant debris facilitate abrasion
• regulation occurs (water melting under pressure and then refreezing)
• plucking

Question 3

Name 3 factors that influence the rate of glacial erosion

Answer 3

• glaciers velocity across the bed
• ice thickness - so the power of the glacier to cause shattering
• rock debris - its quantity and shape
• whether freeze-thaw weathering is occurring
• the bedrock characteristics

Question 4

erosion rates are most intense when glaciers are …? based, thick and …? moving

Answer 4

1. warm based
2. fast

Question 5

Name the glacial erosional feature from its description.

An armchair-shaped hollow on a hillside above a glacial valley

What scale is it?

Answer 5

cirque

Macro

Question 6

Name the glacial erosional feature from its formation

A pre-glacial hollow is enlarged by plucking and abrasion as ice moves in a rotational manner under gravity

Answer 6

cirque

Question 7

Name the glacial erosional feature from its description

A narrow ridge between two cirques

What scale is it?

Answer 7

Arete

macro

Question 8

Name the glacial erosional feature from its formation

As two cirques are enlarged back to back, the ridge between them becomes increasingly narrowed

Answer 8

Arete

Question 9

Name the glacial erosional feature from its description

A sharp, pointed hilltop

What scale is it?

Answer 9

Pyramidal Peak

macro

Question 10

Name the glacial erosional feature from its description

A steep-sided, flat-floored, straight valley

What scale is it?

Answer 10

Trough or U-shaped Valley

macro

Question 11

Name the glacial erosional feature from its description

A steep and possibly rocky section of a side crop

What scale is it?

Answer 11

Truncated Spur

macro

Question 12

Name the glacial erosional feature from its description

A small tributary valley high above the floor of trough often with a waterfall

What scale is it?

Answer 12

Hanging Valley

macro

Question 13

Name the glacial erosional feature from its description

Asymmetrical bare rock outcrop with a gently side facing up-valley

What scale is it?

Answer 13

Roche moutonnee

meso

Question 14

Name the glacial erosional feature from its description

Grooves on exposed rocks

What scale is it?

Answer 14

Striations

micro

Question 15

Name the glacial erosional feature from its formation

As three or more cirques are enlarged the hilltop between them becomes increasingly sharp and pointed

Answer 15

Pyramidal Peak

Question 16

Name the glacial eorsional feature from its formation

A pre-glacial river valley is widened and deepened by erosion from an advancing glacier

Answer 16

Trough or U shaped Valley

Question 17

Name the glacial erosional feature from its formation

The pre-glacial interlocking spurs of the river valley are eroded by the much more powerful glacier

Answer 17

Truncated Spur

Question 18

Name the glacial erosional feature from its formation

Tributary glaciers with small amounts of ice did not erode their valley floor as deeply as the main glacier and so are left at a higher altitude

Answer 18

Hanging Valley

Question 19

Name the glacial erosional feature from its formation

As ice crosses a resistant rock outcrop, the increased pressure causes melting and basal sliding and the up-valley side is smoothed by abrasion. On the leeward side pressure is reduced, refreezing occurs and plucking takes place, causing a steep, jagged slope

Answer 19

Roche moutonnee

Question 20

Name the glacial erosional feature from its formation

Abrasion by debris embedded in the base of the glacier as it passed over bare rock. They can indicate the direction of ice movement

Answer 20

Striations

Question 21

Name the glacial erosional feature from its description

a long and deep, finger-shaped lake, usually found in a glacial trough

what sale is it?

Answer 21

Ribbon or finger lake

meso

Question 22

Name the glacial erosional feature from its description

irregular chips and fractures in the rock

What scale is it?

Answer 22

Chatter marks

micro

Question 23

Name the glacial erosional feature from its description

small rounded hills with no vegetation with small lakes

Answer 23

Knock and lochan landscape

Question 24

Name the glacial erosional feature from its formation

The lochs are formed by overdeepening and the knocks are more resistant bedrock.

Answer 24

Knock and lochan landscape

Question 25

Name the glacial erosional feature from its description A landform consisting of a rock hill and tapering ridge

Answer 25

Crag-and-tail

Question 26

Name the glacial erosional feature from its formation This featured is formed when glacial ice is forced around a large and resistant rock obstacle, such as a voltaic plug, which protects the less-resistant material on the leeside causing the feature to taper into a tail in the down-glacier direction

Answer 26

Crag and tail a famous example is that Edinburgh castle is built upon a crag and tail

Question 27

Supraglacial refers to material...

Answer 27

on the surface of a glacier

Question 28

Englacial refers to material...

Answer 28

dispersed throughout the interior of a glacier

Question 29

Subglacial refers to material...

Answer 29

Debris which has been released from ice at the base of a glacier

Question 30

Name the glacial erosional feature from its description A rock of unspecified shape and size, transported a significant distance from its origin by a glacier or iceberg and deposited by melting of the ice Give an example of where they are found and what they show

Answer 30

Erratic erratic from Scandinavia have been found in boulder clay of the Northumberland, Durham and Yorkshires coasts the the Northeast of England - confirming the presence of the continental ice sheets from Scandinavia

Question 31

Name the 4 main processes by which glaciers deposit material

Answer 31

1. Lodgement 2. Ablation 3. Deformation 4. Flow

Question 32

Describe how glaciers deposit their material by lodgement

Answer 32

Lodgement occurs when the friction between the subglacial debris and the bed becomes greater than the drag of the ice moving over it. It is commonly associated with glaciers carrying huge loads of debris and where the glacier is very slow moving, if not static

Question 33

Describe how glaciers deposit their material by ablation

Answer 33

this process refers to debris being dumped as the glacier melts and thaws. It can include supraglacial and englacial material, as well as subglacial material.

Question 34

Describe how glaciers deposit their material by flow

Answer 34

occurs if high meltwater content causes the glacial debris to creep/slide or flow during deposition.