Periglacial processes and landscapes

Created by

Lucas B

Cards (12)

What is permafrost?
Permanently frozen ground, including soil, sediment, or rock
What is the active layer of permafrost?
The top layer of the soil that thaws and refreezes seasonally
How does frost shattering/freeze thaw weathering occur?
Water that gets into the cracks of a rock turns to ice and expands when the temperature goes below freezing, and as the freezing and thawing process is repeated, cracks form and become larger until chunks of rock break off and pile up at the foot of a slope as scree
What landform does frost shattering/freeze thaw weathering create?
Blockfields - Large deposits of scree create areas of broken up, angular fragments of rock
How does nivation occur?
Through any processes related to snow
What landform does nivation create?
Nivation hollows - Summer meltwater which carries away any weathered rock debris, revealing a small hole
How does frost heave occur?
In low temperatures, the ground contracts and cracks develop so that in the summer, meltwater fills them and this is then frozen again in winter to form ice wedges due to frost heave
What landform does frost heave create?
Stone polygons - Frost heave causes the ground to expand and lift soil particles upwards, and as smaller particles might be removed by wind, this leaves a concentration of larger stones lying on top
How does groundwater freezing occur?
The freezing of water in the upper layers of the soil leads to expansion of the ice within it
What landform does groundwater freezing create?
Pingos - Groundwater freezing causes the overlying sediments to heave upwards into a dome shaped feature
What is solifluction, and what is it caused by?
Caused by meltwater, solifluction is the slow downhill flow of saturated soil, where the active layer provides enough water to allow flow to occur
What are loesses, and what are they caused by?
Caused by wind, loesses are large amounts of loose sediment which has been picked up and deposited away from its original location