glacial quarrying

Glacial quarrying, also known as glacial plucking, is a geological process where glaciers remove larger pieces of rock from the bedrock beneath them. This occurs as ice is forced around obstacles, creating differential stresses that can fracture the rock along existing joints or cracks. The removed rock fragments then become part of the glacier's abrasive tools.1

This process, along with abrasion, contributes to glacial erosion. Abrasion involves the grinding and scratching of the bedrock by rock debris embedded in the glacier's base. The size and type of debris, from fine particles to large boulders, determine the nature of the "tool-marks" left behind, such as microscopic scratches or deep gouges. These marks, including striations and chatter marks, indicate the direction of ice movement. P-forms and glacial grooves are other erosional features of uncertain origin, possibly formed by pressurized mud slurries beneath the glacier.123