Chatter marks are small, curved fractures found on glaciated rock surfaces, formed by the jerky movement of a glacier over bedrock. These marks are typically crescent-shaped and provide important clues about the direction of glacial movement and the nature of glacial erosion. Chatter marks are studied in the field of glacial geomorphology.
Source Boulton, G. S. (1974). “Processes and Patterns of Subglacial Sedimentation: A Theoretical Approach.” Geological Society of America Bulletin, 85(3), 439-445.