Seasonal snow collects in shallow depressions and moves slowly downslope.
2 of 19
Explain how frost heave occurs.
The upward swelling of soil due to the growth of ice lenses within the soil. The ice lenses are fed by capillary action or groundwater flow from below.
3 of 19
Explain how thermal contraction occurs.
The shrinkage of the ground surface due to extreme low temperatures, creating cracks in the surface with a regular, interlocking pattern of polygons.
4 of 19
Explain how freeze-thaw weathering occurs.
On freezing, water expands by 9% in volume. Repeated cycles of freezing and thawing of water in cracks in rocks spilt rocks into progessively smaller blocks.
5 of 19
Explain how solifluction occurs.
A type of mass movement, or soil creep, found on low-angle slopes: saturated soil of the active layer flows very slowly downslope in the summer but freezes in the winter.
6 of 19
Explain how wind erosion and deposition occurs.
Periglacial areas often have strong winds, and these can erode the finely ground rock debris produced by glaciers and ice caps.
7 of 19
What is the related landform to nivation?
Nivation hollows
8 of 19
What is the related landform to frost heave?
Pingos
9 of 19
What is the related landform to thermal contraction?
Ice wedge polygons
10 of 19
What is the related landform to freeze-thaw weathering?
Blockfields and scree
11 of 19
What is the related landform to solifluction?
Solifluction terraces and lobes
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What is the related landform to wind erosion and deposition?
Loess fields
13 of 19
How is a nivation hollow formed?
Weathering, erosion and meltwater fow caused by the snow's movemet deepen the depression into a bowl-shaped hollow.
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How is a pingo formed?
These are circular, soil covered mounds up to 70m high which have an ice core usually fed by a groundwater source from below allowing the ice core to swell upward forcing the soil mound move upwards.
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How are ice wedge polygons formed?
Ice wedges form when spring meltwater pools in thermal contraction cracks, only to refreeze when it hits permafrost below. Over many seasons, the ice wedge grows in thickness.
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How are blockfields and scree formed?
Frost-shattering, angular rock fragements can form on a flat surface as a blockfield, or at the base of a slope, forming scree.
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How are solifluction terraces and lobes formed?
Solifluction produces vegetated lobes or terraces giving a slope a 'stepped' profile.
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How are loess fields formed?
Extensive areas of wind-blown glacial sediment found at the margins of ice.
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Other cards in this set
Card 2
Front
Explain how nivation occurs.
Back
Seasonal snow collects in shallow depressions and moves slowly downslope.
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