Unit 4 Notes

Question 1

What is glacial transportation?

Answer 1

Sediment, transported by a flowing ice body.

Question 2

What is fluvial transportation?

Answer 2

Sediment transported by flowing meltwater.

Question 3

Which processes affect supraglacial debris?

Answer 3

Glacial and Fluvio glacial.

Question 4

Which processes affect englacial debris?

Answer 4

Glacial and fluvioglacial.

Question 5

Which processes affect subglacial debris?

Answer 5

Glacial and fluvioglacial.

Question 6

Which processes affect proglacial debris?

Answer 6

Fluvioglacial.

Question 7

What is erratic?

Answer 7

Different rock types to the bedrock they sit on.

Question 8

What will extensional flow result in?

Answer 8

Supraglacial debris falling down crevasses becoming englacial debris.

Question 9

What will compressional flow lead to?

Answer 9

Sub or englacial material being moved towards the surface, and becomes supraglacial debris.

Question 10

Which landforms are glacial?

Answer 10

Drumlins, Recessional moraine, terminal moraine, lateral moraine, medial moraine, push moraine.

Question 11

Which landforms are fluvioglacial?

Answer 11

Eskers, Kames, Kame terraces, Kettle holes, Kettle lakes, varves.

Question 12

Where are glacial landforms found?

Answer 12

A till plain.

Question 13

Where are fluvioglacial deposits found?

Answer 13

Outwash Plain.

Question 14

What is lodgement till?

Answer 14

Till formed subglacially being plastered onto underlying surface. Friction between debris and bed - greater than drag produced by ice moving over it.

Question 15

What is ablation till?

Answer 15

Till deposited from sub, en, and supraglacial debris, due to ablation poorly sorted, unstratified.

Question 16

What is deformation till?

Answer 16

Underlying till being folded or faulted when a glacier re-advances.

Question 17

What is a moraine?

Answer 17

An accumulation of glacial debris deposited by a glacier.

Question 18

What is a till plain?

Answer 18

Glacial moraines covering large areas of land, producing a flat area.

Question 19

What is the fluvial theory of drumlin formation?

Answer 19

Drumlin formation is due to sub-glacial meltwater flooding, depositing fluvioglacial material.

Question 20

What is the deformational theory?

Answer 20

When a glacier moves over an obstacle at the base of the glacier, till is plastered around it. Lodgement till becomes streamlined as the glacier flows over it.

Question 21

When do medial moraines form?

Answer 21

When two glaciers converge, becoming a lateral moraine.

Question 22

What are lateral moraines formed from?

Answer 22

Piles of glacially-transported rocks, debris dropped by ice.

Question 23

What do terminal moraines mark?

Answer 23

The furthest advance of a glacier.

Question 24

Where is debris deposited?

Answer 24

The furthest point which the glacier reaches.

Question 25

What is the difference between recessional and terminal moraines?

Answer 25

Recessional moraines are formed where the glacier pauses for a considerable time during its retreat.

Question 26

When do push moraines form?

Answer 26

When a glacier advances over existing moraine.

Question 27

What are the characteristics of glacial till?

Answer 27

Poorly sorted, different shapes and sizes, no stratification, angular and sub-angular.

Question 28

What are the characteristics of fluvioglacial till?

Answer 28

Well sorted, clear stratification, rounded/sub-rounded debris.

Question 29

What does sorting refer to?

Answer 29

The arrangement of rock fragments into similar sizes.

Question 30

What does stratification refer to?

Answer 30

The layering of similar sized clasts.

Question 31

Are eskers subglacial or supraglacial?

Answer 31

Subglacial.

Question 32

What is the first step in the formation of an esker?

Answer 32

Running water at a high velocity due to hydrostatic pressure transports a large quantity of sediment which become rounded due to extensive attrition.

Question 33

What is the second step in esker formation?

Answer 33

Fluctuating velocities due to seasonal variations in meltwater enable deposition to occur.

Question 34

What is the third step in esker formation?

Answer 34

The tunnel may become blocked, stopping the flow of water.

Question 35

What is imbrication?

Answer 35

Clasts aligning themselves in the direction of the flowing water.

Question 36

Do kames form supra or subglacially?

Answer 36

Supraglacially.

Question 37

What happens in the zone of ablation?

Answer 37

Surface meltwater streams pick up and transport supraglacial debris.

Question 38

What happens to meltwater streams in the zone of ablation?

Answer 38

They flow into lake depressions, on the ice surface. If the lake is at the glacier edge, a kame terrace forms. Away from the edge, a kame forms.

Question 39

What are the steps in formation of a kame?

Answer 39

Initial ice surface, ice surface melts and is lowered, continued ablation lowers ice surface, ice disappears, kames have been deposited on valley floor.

Question 40

Why are kame clasts angular?

Answer 40

Debris is only being moved a short distance, so there isn't room for attrition.

Question 41

Why are kames sorted and unstratified?

Answer 41

Seasonal variation means there will be bands of rock which are similar in size.

Question 42

Why are kame terraces larger?

Answer 42

Freeze thaw weathering on the valley side.

Question 43

What are kettle holes?

Answer 43

Depressions found within the outwash plain located in front of a retreating glacier.

Question 44

What are the first two steps of kettle holes formation?

Answer 44

Blocks of ice are left behind by retreating glacier. Sediment shed from retreating glacier buries ice blocks.

Question 45

What are the last two steps of kettle hole formation?

Answer 45

Ice blocks melt away, and sediment collapses, groundwater falls in kettles.

Question 46

What are the characteristics of varves?

Answer 46

Stratified, made up of fine material.

Question 47

Why does a varve have coarse and fine layers?

Answer 47

Warmer summer months mean more ablation, faster streams, and transport of coarse materials. Colder winter months mean lower temperatures, less ablation, slower flowing streams, transport of fine materials.

Question 48

What is an outwash plain?

Answer 48

A flat landscape formed by fluvioglacial deposition in front of a retreating ice sheet.