Lieser said the straight lines are due to the structure of the snow crystals, and how they break apart and react to stresses.
Like all icebergs, Brunt said only 10 percent of this particular tabular berg was visible above the waterline, with the majority of it submerged. The berg appears toward the end of the clip on the left.
Brunt explained the rectangle was likely formed by a process that's fairly common along the edges of icebergs.
When we think of icebergs, we tend to think of huge chunks of ice with pointy spires and domes, with its bulk extending down below the surface of the water. Larsen C itself calved an even larger iceberg in 1986, Shuman said. "If you look at the recent icebergs that calved of iceberg A-68 (near Larsen C), you will see that many of them have pretty "rectangularish" shapes".
The incredibly clean edges indicate how new this iceberg is, as the wind and the sea have yet to erode its flanks.
"The ice shelves that produce the icebergs are extremely flat and expansive, so we often see nearby tabular icebergs similar to the one seen in the photo", Brooke Medley, NASA's Operation IceBridge deputy project scientist, added over email. They are wide, flat, and long and are characterized by steep, almost vertical sides and a flat plateau top.
"The Larsen C is a large ice shelf".
NASA spotted the on October 16 during one of its IceBridge Flights, a program that tracks the global climate system.
Categorized as a tabular iceberg, the square-like iceberg was estimated to be over a mile across.
"There's no one going around with a chain saw and chopping it off. Nature does sometimes go on square angles", he said.
Since the iceberg has sharp angles and a flat surface, NASA suggests it came from a calving event that occurred recently.
The Larsen C ice shelf is just one of many climate scientists are monitoring.