Periglacial Landforms

Question 1

What is patterned ground?

Answer 1

Ground with surface material distributed across it in a pattern

Question 2

How is patterned ground formed?

Answer 2

Freeze thaw - when soil enters the soil or rocks and freezes, it expands. This expansion causes the ground to heave, or move upward

Seasonal movement - during the warmer months, the frozen ground thaws, allowing the rocks and debris to shift slightly

Question 3

What are ice wedges?

Answer 3

V shaped cracks that form in the ground due to the expansion of ice when it freezes within cracks in the soil

Question 4

How are ice wedges formed?

Answer 4

Water infiltration - during warmer months, water from melted snow can seep into the cracks. When temperature drops again, this water will freeze, causing expansion and forcing the cracks to widen

Question 5

What are pingos?

Answer 5

Mounds of earth with a core of ice

Question 6

How are pingos formed?

Answer 6

Groundwater freezing - when unfrozen groundwater rises towards the surface and freezes - occurs in areas where the active layer is thin

Expansion of ice - as groundwater freezes, it expands. This expansion creates pressure, causing the surrounding soil to be pushed upwards forming a mound / hill