Antarctica's glaciers are constantly moving towards the sea, and when they get there the chunks that break off become icebergs. These are also formed by the breakup of ice sheets, dramatically illustrated by the story released yesterday about the disintegration of the Wilkins ice sheet, an even that actually happened while we were there, but was 375 miles south of us.


We didn't see icebergs as massive as those produced by the Wilkins ice sheet, but some were quite large. The one above was about 10 stories tall!


The iceberg above is called a tabular iceberg, so named because it sports a tabletop-like surface. This specimen was about the size of a city block and so impressed our Captain that he circled it on our way by and several of the crew members joined us on deck to take pictures! Considering the fact that only about 10% of an iceberg shows above the water, this one was quite large.


Water erodes unusual details in icebergs.


This is a close up of the iceberg in the first photo.


Entirely formed from fresh water, icebergs continually reshape themselves by melting, rolling, and breaking apart. They can change at any moment, so you have to be vigilant when approaching them. Tide lines betray their former selves, and the one above once sat farther down in the water than it does today. When an iceberg undergoes a 'transformation', it will dramatically bob up and down in the water until it reaches equilibrium.


Above, a large slab iceberg drifts by.