glacial groove

Glacial grooves are linear depressions, often straight or curved, found on rock surfaces that have been scoured by glaciers. These features can range from tens of centimeters to meters in width and depth, with cross-sections that are frequently semicircular or parabolic. The walls of glacial grooves are typically striated parallel to their long axis, indicating ice flow within them. While some researchers believe these grooves were carved directly by ice, others suggest they were formed by pressurized mud slurries flowing beneath the glacier.1

These grooves are distinct from larger striations, which are scratches cut by a single tool and also indicate the direction of ice movement. The study of striations and related features like chatter marks and knob-and-tail formations helps geologists determine the direction of past ice flow.12