Antarctica is drained by outlet glaciers, ice streams, and ice shelves. Most ablation occurs by calving or bottom melting of ice shelves. An Ice stream is an area of rapidly flowing ice, bounded by slowly moving ice.
Ice streams drain ice caps or ice sheets.
Velocities of ice streams can be as high as 1-2 km per year. An outlet glacier is a flow of ice from an ice cap or ice sheet that is bounded by bedrock valley walls. The fastest flowing outlet glacier has a velocity of 8 km per year. The profile of ice streams very gentle profile near margin of ice stream. Ice Cores and Climate Records from Ice Sheets ice core drilling annual layers of snow become layers of ice by analyzing oxygen isotopes in the ice, a temperature record for last 150,000 years can be reconstructed.