Description
It is estimated that the volume of the Antarctic ice sheet is about 25.4 million km3, and the WAIS contains just under 10% of this, or 2.2 million km3. The weight of the ice has caused the underlying rock to sink by between 0.5 and 1 kilometres in a process known as isostatic depression.
Under the force of its own weight, the ice sheet deforms and flows. The interior ice flows slowly over rough bedrock. In some circumstances, ice can flow faster in ice streams, separated by slow-flowing ice ridges. The inter-stream ridges are frozen to the bed while the bed beneath the ice streams consists of water-saturated sediments. Many of these sediments were deposited before the ice sheet occupied the region, when much of West Antarctica was covered by the ocean. The rapid ice-stream flow is a non-linear process still not fully understood; streams can start and stop for unclear reasons.
When ice reaches the coast, it will continue to flow outward onto the water. The result is a large, floating shelf of ice affixed to the continent.
Read more about this topic: West Antarctic Ice Sheet
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