Episode 129: Glaciers, Ice, and Groundwater

Frost Heaving

Frost heaving is a significant process in periglacial landscapes, where frozen soil expands and pushes upwards, causing layers of soil to rise by as much as 30 cm. This phenomenon can create substantial challenges for land use and infrastructure. James Fodor explains that frost heaving can lead to the formation of ice wedges, which further disrupt the soil by expanding and contracting over time 1.

This can result in really huge ice wedges, which freeze as a result of freezing and thawing over periods of many years, exerting large forces and pressure on the surrounding soil.

--- James Fodor

These processes highlight the dynamic and often disruptive nature of frost action in cold regions.

   

Ice Wedges

Ice wedges are another critical feature in periglacial landscapes, formed by the repeated freezing and thawing of water in soil cracks. James Fodor describes how these wedges gradually widen and deepen, exerting significant pressure on the surrounding soil and rock 1. This process can create large ice wedges over many years, impacting the stability of the land.

It's a gradual process of kind of squeezing and levering apart the land in that particular region.

--- James Fodor

The cumulative effects of ice wedges contribute to the unique and often challenging terrain in periglacial areas.

   

Patterned Ground

Patterned ground refers to geometric patterns that naturally form in the soil of periglacial regions. These patterns, often resembling squares or triangles, are created by the differential expansion and contraction of finer and larger sediments. James Fodor notes that these formations can appear man-made but are entirely natural 1.

There's geometric patterns that form in the ground with relatively symmetrical and relatively regular shapes.

--- James Fodor

This phenomenon illustrates the intricate and fascinating ways in which frost action shapes the landscape.

   

Permafrost

Building infrastructure on permafrost presents unique challenges due to the ground's susceptibility to thawing. James Fodor explains that heat from buildings or pipelines can melt the permafrost, destabilizing structures 2. Solutions include building on stilts or using thick gravel pads to insulate the ground.

The heat of the building or pipeline will typically warm up the permafrost and then partially melt the ground underneath it, thereby destabilizing the structure.

--- James Fodor

Additionally, thawing permafrost releases significant amounts of greenhouse gases, contributing to global warming and creating a feedback loop that further accelerates permafrost melt 3.