The breaking away of a mass of ice from an iceberg, ice front, or glacier, caused by: wind and/or wave action; over-extension of an ice shelf; or a collision with an older iceberg. Calving represents the major form of ablation from a glacial system. See Benn et al. (2006) PPG 30, 3 and Skvarca et al. (2002) Quat. Sci. Revs 21.