Episode 129: Glaciers, Ice, and Groundwater

Formation

Glaciers form through the accumulation and compaction of snow over time, leading to the creation of dense ice masses. James Fodor distinguishes between alpine glaciers, found in mountainous regions, and continental glaciers, which cover vast areas of land. He explains basal sliding, where meltwater acts as a lubricant, allowing glaciers to slide over their beds, and bed deformation, where the glacier's weight deforms the underlying sediment, aiding its movement 1.

   

Movement

Glaciers move through a combination of basal sliding, bed deformation, and internal deformation. Basal sliding occurs at the glacier's base, facilitated by meltwater, while bed deformation involves the glacier pulling the underlying sediment along with it. Internal deformation refers to the plastic bending and brittle cracking within the glacier itself 2.

   

Seasonal Changes

Seasonal changes significantly impact glaciers, with net mass loss during summer and net mass gain during winter. James Fodor notes that most glaciers have been retreating since the 1850s, a trend accelerated in recent decades 3.

   

Surges

Glacial surges are periods when glaciers move up to 100 times faster than normal. These surges, though not fully understood, are thought to be influenced by factors like meltwater availability and bed deformation 4.