Satellite imagery captured the rupture, which occurred about 10 years after satellite monitoring spotted growth in a previously dormant crack in the ice known as Chasm-1, and nearly two years after a slightly smaller iceberg called A74 separate from the same ice shelf. An abyss is a fissure in the ice shelf that extends from the surface to the ocean below, while an ice shelf is a floating piece of ice that extends from glaciers formed on land.
Ted Scambos, a senior research scientist at the University of Colorado at Boulder, wrote in an email that while the iceberg is “a massive mass of ice, about 500 billion tons… it’s far from the largest iceberg ever.” ever seen rivaled Long Island.”
The calving event is not expected to affect BAS’s Halley Research Station, which was moved further inland as a precaution in 2016 after Chasm-1 began to grow.
“However, the new fracture puts the base about 10 miles from the ocean, and new fractures could appear in the next few years, forcing another expensive station move,” Scambos wrote. The new iceberg is expected to follow a similar path as the A74 into the Weddell Sea and will be named by the US National Ice Center.
Unlike some previous icebergs and collapsed ice shelves that have been associated with climate changeThe BAS press release said the rupture was a “natural process” and that there was “no evidence that climate change played a significant role.”
Rather, the canyon began to grow because “stress was building up… because of the natural growth of the ice shelf,” said Hilmar Gudmundsson, a glaciology researcher at Northumbria University, in a BBC Story 2019.
Scambos compares the calving of the iceberg to a chisel on a wooden board. “In this case, the chisel was a small island called ‘MacDonald Ice Rise,'” wrote Scambos. “The ice was pushed against this rocky seamount by the ice flow, forcing it to split and eventually break off the floating ice shelf.”
“These large iceberg calvings, sometimes the size of a small state, are spectacular. But they’re just part of how the Antarctic ice sheet works,” Scambos said. “Most of the time they have nothing to do with climate change.”