Periglacial landforms:

Question 1

What is patterned ground?

Answer 1

Patterned ground is formed through the frost heave of stones in and underneath the active layer. May create polygons or stripes.

Question 2

What are ice wedges?

Answer 2

Water infiltrates small cracks in the
permafrost and expands on freezing (frost action). Water then fills the expanded ground. The process repeats and leaves a large ice wedge.

Question 3

How do Pingo’s form and what are the 2 types of Pingo’s?

Answer 3

Ground is forced upwards through frost heave of an ice lens, leaving a mound. The mound can be an open or closed pingo.

Question 4

What is an open pingo?

Forms in discontinuous permafrost

Answer 4

water groups together

Water freezes and creates an ice lens

● The ice lens continues to grow and
pushes the unfrozen ground upwards

Question 5

What is a closed pingo?

Forms in continuous permafrost

Answer 5

1) Under a lake, permafrost is
insulated and melts.

2)The lake will eventually dry

3) ice lens will develop through
capillary action

4) When temperatures drop, permafrost
advances and frost heaves the
unfrozen ground upwards, creating a
mound.

Question 6

What are blockfields?

Answer 6

A rock-strewn landscape caused by
extensive frost action of the landscape.

Question 7

What is solifluction?

Answer 7

The downslope movement of rock and soil material in response to gravity.

Question 8

What are solifluction lobes?

Answer 8

When the active layer thaws and solifluction occurs, tongue-shaped lobes of soil fall down a slope.

Question 9

What are Terracettes?

Answer 9

Frost heave pushes particles of soil upwards, which would usually fall downhill through the process of creep. However, vegetation blocks the soil from falling, meaning it stays
behind in a step shape. The shape of
terracettes can be described as terraces.

Question 10

What is thermokarst?

Answer 10

Marshy, boggy wetlands caused when permafrost melts.

This can leave holes in the
ground, which will also fill with meltwater.