Perfectly rectangular iceberg floating off Antarctica looks deliberately cut. Here’s how it really got that way

A massive iceberg spotted off Antarctica is upending public expectations of classic Titanic-esque icebergs with sharp spires jutting from the ocean surface.

An aerial photo taken last week and shared by Nasa captured a rectangular slab of ice sliced so smoothly that it appears unnatural – deliberately cut, even. Experts say they believe the iceberg fractured in May from Larsen C, a large ice shelf fed by several glaciers on the east side of the peninsula. They’re still unsure whether it will cause the rest of the shelf to destabilise.

“Ice shelves release large icebergs from time to time. They do this naturally,” said Christopher Shuman, a research scientist at the University of Maryland Baltimore County’s Joint Centre for Earth Systems Technology at Nasa. It means that the ice shelf is changing, which is not surprising given the changes scientists have seen nearby, he said.

Larsen A, an ice shelf farther north on the peninsula, broke up in 1995. Larsen B broke up in 2002. Larsen C itself calved an even larger iceberg in 1986, Shuman said. It was recorded at 7,200 sq km – larger than Maryland – until last July, when it calved a smaller iceberg the size of Delaware, known as A-68.

The rectangular iceberg, photographed as part of a topographic mapping project tracking changes in polar ice shelves called Operation Ice Bridge, fractured in May after A-68 crashed into Bawden, a rocky ice-covered island in the northwest, and created several small berg fragments.