Periglacial Landforms And Processes

Question 1

Cree and block field

Answer 1

Process = freeze thaw
Water gets into cracks, freezes, expands, and breaks off chunks of rock.
The debris falls off the rock face and becomes scree.
Called block field if it’s on flat ground (larger blocks)

Question 2

Nivation hollows

Answer 2

Process = nivation
A crack that has been deepened by nivation
(Physical and chemical processes under a patch of snow)
Often is the beginning of a Corrie

Question 3

Solifluction sheets and lobes

Answer 3

Process = solifluction
Solifluction happens when the active layer thaws and the ground becomes heavy and waterlogged.
The soil slumps forming terraces or steps (solifluction sheets)
Loves are curved
Only happens on ground more than 2° gradient.

Question 4

Stone polygons and stripes

Answer 4

Process = frost heave
Stones in the soil have a lower heat capacity so they stay colder.
They freeze the ground below them which expands and pushes them up.
Repetition causes the stone to reach the surface.
These stones form polygons around hummocks.
On slopes over 6° they form stripes

Question 5

Ice wedge polygons

Answer 5

Process = ground contraction
As the ground freezes and thaws, it expands and contracts.
The contractions cause the formation of cracks.
Water gets into these cracks and freezes and widens and deepens them.
1-2m wide and 2-3m deep.

Question 6

Pingos

Answer 6

Process = groundwater freezing
It is a dome shaped layer of soil surrounding an ice core.
Happens in sporadic permafrost
Water is drawn up by hydrostatic pressure and freezes to form an ice core.
This rises, pushing the active layer up, thus forming a pingo.

Worlds largest = IBYUK

Question 7

Loess and ventifacts

Answer 7

Process = wind erosion
Ventifacts are stones or boulders smoothed by wind erosion.
Loess = fine powdery material that has been carried by the wind over long distances.

These are found in glacial areas because they are flat and the wind has a chance to pick up to high speeds.