Weathering
This is essentially the freeze and thaw that causes large fragments of rock to be fractured from the main body of rock as the water crystallises, expanding its volume and pressure in gaps and seems in the rock.
Ground Ice
The most common form of ground ice is pore ice. Pore ice develops in the pore spaces between soil and sediment particles where liquid water can accumulate and freeze.
Ice wedges are downward narrowing masses of ice that are between 2 to 3 meters wide at the base and extend below the ground surface up to 10 meters. It is believed that they form when a seasonal crack in the ground forms in the winter. The diagram below shows the process:
Mass movement
The are different types of mass movement including Solifluction which is the downward movement of soil particles that are saturated. the slope does not have to be steep for this to happen. Also Frost creep which is the movement of similar soil and sediment but this is caused by frost freezing and melting. Particles move slowing through this process and gravity. Another type is rock falls as periglacial environments are harsh soil does not deposit easily and there is a lot of bare rock that is exposed the the harshness of the weather causing cracking etc causing the rocks to become unstable.
Erosion
Processes of erosion and deposition in periglacial parts of the world tend to have their own unique character. These characteristics are related to the importance of freeze-thaw action, the presence of strong winds, and the fact that the warm season is very short.
The landforms that have developed due to these processes are remarkable in character and will be discussed in the next blog. Understanding these processes could be contrasted with the processes of the riparian environment.
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