Permafrost

What is a pingo/how does it form?

A conical mound cored by segregation ice

What causes the formation of patterned ground?

After being brought up by frost push, frost heaves sorts soil and rock domain.

What is a thermokarst/how does it form?

An uneven surface resembling limestone karst that results from the thawing of ice-rich permafrost

What is permafrost/how does it form?

Any rock or soil at or below freezing temperature of water. Remains at this temperature for at least two years, with ice not necessarily present.

Frost Push

As a freezing front freezes ground from top down, the difference of specific heat capacity allows boulders to be cooled down faster, resulting in the stone to expand and push up much faster than the rest of the material.

Why/how do saturated fines rise during summer thaw?

As soil is thawed from top down, it becomes more dense. The unfrozen, saturated fines are now less dense and rise to the top.

Talik

Soil that remains unfrozen year-round.

What are the three main controls on polygon morphology?

Stone concentration, relative strength of lateral sorting/squeezing, and the hill-slope gradient.

What is/why does segregation ice form?

The formation of discrete layers or lenses of ice as a result of the migration and subsequent freezing of pore water.

Active Layer

The overlying surface that freezes in the winter and thaws in the summer