Glacial Plucking

Glacial plucking, also called quarrying, is the process by which a glacier pulls loose blocks of bedrock from its bed and carries them off within the ice. Meltwater refreezes around joints and fractures on the down-glacier side of a rock obstacle, binding the fragmented rock to the glacier sole, and as the ice continues moving forward it wrenches the bound blocks free. Plucking works together with abrasion, the grinding of the bed by the debris the ice already carries, to be the two principal mechanisms of glacial erosion. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/