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Ice calving, also known as glacier calving or iceberg calving, is the breaking of ice chunks from the edge of a glacier. [1] It is a form of ice ablation or ice disruption . It is the sudden release and breaking away of a mass of ice from a glacier , iceberg , ice front , ice shelf , or crevasse .
A glacier is a persistent body of dense ice, a form of rock [2]) formed from snow falling and accumulating over a long period of time; glaciers move very slowly, either descending from high mountains, as in valley glaciers, or moving outward from centers of accumulation, as in continental glaciers.
The seasonally melting glacier deposits much sediment at its fringes in the ablation area. Ablation constitutes a key part of the glacier mass balance. The amount of snow and ice gained in the accumulation zone and the amount of snow and ice lost in the ablation zone determine glacier mass balance.
A glacier that fills a valley is called a valley glacier, or alternatively, an alpine glacier or mountain glacier. [14] A large body of glacial ice astride a mountain, mountain range, or volcano is termed an ice cap or ice field. [15] Ice caps have an area less than 50,000 km 2 (19,000 sq mi) by definition.
The accumulation zone is found at the highest altitude of the glacier, where accumulation of material is greater than ablation. On a glacier, the accumulation zone is the area above the firn line, where snowfall accumulates and exceeds the losses from ablation, (melting, evaporation, and sublimation).
Water from a moulin often exits the glacier at base level, sometimes into the sea, and occasionally the lower end of a moulin may be exposed in the face of a glacier or at the edge of a stagnant block of ice. Water from moulins may help lubricate the base of the glacier, affecting glacial motion.
Using data collected from 13 Alaskan tidewater calving glaciers, Brown et al. (1982) derived the following relationship between calving speed and water depth: = +, where is the mean calving speed (m⋅a −1), is a calving coefficient (27.1±2 a −1), is the mean water depth at glacier front (m) and is a constant (0 m⋅a −1). Pelto and ...
During compression, air bubbles are squeezed out, so ice crystals enlarge. This enlargement is responsible for the ice's blue colour. This enlargement is responsible for the ice's blue colour. Small amounts of regular ice appear to be white because of air bubbles inside and also because small quantities of water appear to be colourless.