Processes & Landforms Of Erosion

Question 1

Name the 4 Variables controlling rate of erosion:

Answer 1

• Glaciological
• Substratum
• Temporal
• Topographic

Question 2

What is glaciological?

Answer 2

• ice processes at the bed.

Basal sliding, stress, glacial drainage, shear stress, debris entrainment.

Question 3

Temporal

Answer 3

• Duration of Glaciation

Question 4

Topographic

Answer 4

• Type of land
  Morphology of bed.

Roughness, channel type, catchment size, gradient.

Question 5

Substratum

Answer 5

Characteristics of the ice.

Permeability, porous, thickness, lithology.

Question 6

4 types of Erosion:

Answer 6

Debris entrainment
Plucking and quarrying
Abrasion
Meltwater erosion

Question 7

Plucking and Quarrying

Answer 7

Regelation, causes rocks to be plucked up into the base of the glacier.
Has to be pre existing cracks to do so.

Question 8

Meltwater erosion

Answer 8

Water interacting with rocks

Cold water has more co2 dissolved, more acidic, can erode carbonate rocks more easily. Chemical erosion.

Question 9

Debris entrainment

Answer 9

Meltwater at base refreezes and incorporates debris which pushes debris up into glacier through ice deformation and thrusting causing sheets pushing up through ice.

Question 10

Factors of glacier that promote erosion.

Answer 10

Velocity
Amount of meltwater at base.
How quickly glacier can re freeze. Quickly refreezes means more plucking.

Question 11

Micro scale and macroscale

Answer 11

Micro = less than 1m
Macro = larger than 1km

Question 12

Types of micro

Answer 12

Chattermarks (hammered in C shapes), striations, Rat-tail (rips out bits of sediment and drags them out) and fractures.
P- forms.

Question 13

Types of Macro:

Answer 13

Cirque (start of glacier, snow accumulates and erodes deeper and deeper, steep back wall). Fjord (Milford Sound, a parabolic valley, builds or erodes river channel, glacier goes through and then melts and leaves valley).
Aerial scour - large scale sandpapering by extensive warm based ice.