Periglacial processes/landforms#

Question 1

Explain freeze thaw weathering

Answer 1

Water freezes into cracks of rocks, expanding the crack causing erosion through repeated freezing and thawing

Question 2

Landforms produced by freeze thaw weathering

Answer 2

Accumulation of frost shattered rocks

Question 3

Define solifiction

Answer 3

Downslope movement of the saturated active layer due to gravity

Question 4

Landforms produced by solifuction

Answer 4

Tongue shaped gesture at foot of slope
Solifuction lobe

Question 5

Define nivation

Answer 5

Combination of processes which weakens and erodes the ground beneath the snow patch
e.g freeze thaw, solifuction, meltwater erosion

Question 6

Landforms produced by nivation

Answer 6

Causes hollows formed in upland areas

Question 7

Define Frost heave

Answer 7

The freezing and expansion of soil causes the upward dislocation of material.
The freezing water pushed the stones upwards forming a dome

Question 8

Landforms produced by frost heave

Answer 8

Large stones settling on slopes
Domes

Question 9

Define ground water freezing

Answer 9

Water filters down into upper layers of ground then freezing.
Freezing caused the expansion of ice meaning overlying sediments heaved upwards into dome

Question 10

Landforms produced by groundwater freezing

Answer 10

Ice core dome (pingo)

Question 11

Define ground contraction

Answer 11

Dry areas of active layer te freeze causing contraction and cracks. Repeated thawing and freezing causes cracks to widen and deepen

Question 12

Landforms produced by ground contraction

Answer 12

Polygonal patterns on surface
Ice wedge polygon

Question 13

Define Aeolian action

Answer 13

Limited vegetation cover means material is easily picked up and transported fine sediment in surface

Question 14

Landforms produced by aeolian action

Answer 14

Accumulation of deposits (loess)

Question 15

Meltwater erosion

Answer 15

During summer thawing creates meltwater eroding streams.
Regressing in winter causes reduction in discharge and deposition

Question 16

Landforms produced by meltwater erosion

Answer 16

Streams with multiple channels

Question 17

What is permafrost

Answer 17

Permanently frozen ground where the soil temperatures are below 0 for 2+ years

Question 18

4 types of permafrost

Answer 18

Continuous
Discontinuous
Isolated
Sporadic

Question 19

What is discontinuous permafrost

Answer 19

Permafrost is shallower and the permanently frozen ground is fragmented by patches of unfrozen ground.
Surface layer melt during summer

Question 20

What is sporadic permafrost

Answer 20

Occurs where annual temp is only just below 0
Permafrost covers less than 50% of landscape

Question 21

What is isolated permafrost

Answer 21

Occurs less than 10% of area

Question 22

What is the active layer

Answer 22

Upper part of ground that regularly thaws during summer months
Highly mobile moving downslope