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.
Reference: Boulton, G. S. (1974). “Processes and Patterns of Subglacial Sedimentation: A Theoretical Approach.” Geological Society of America Bulletin, 85(3), 439-445.