Antarctica’s eastern coastline recently revealed a largely unknown landform after significant ice shelf loss. The retreat of the Glenzer and Conger shelves exposed a new geographic feature that could soon be named. If confirmed, this island would join a growing list of ice masses that have appeared in recent years as floating glacial debris around the continent’s edges.
The surface is roughly rounded, measuring just over three kilometers in length. It is visible in a trio of natural color images captured by Landsat satellites between 1989 and 2022. Remarkably, the island has maintained its shape even as the enclosing ice shelf fractured and sea ice fluctuated with the seasons.
A bright white disk-like feature remained fixed in position and form even after it detached and drifted onto sizable icebergs following the rapid collapse of the Glenzer and Conger shelves earlier this year.
Its height appears to rise above the surrounding landscape. Elevation data indicate that portions of its mass stand 30 to 35 meters above sea level. These measurements were obtained by the Advanced Topographic Laser Altimeter System on NASA’s ICESat-2 satellite on December 22, 2021.
Image captions note the discovery of the unnamed island and its location.
They wonder whether it is an ice island or real land
Although this mass moves and resembles an island, it may not be a classic landform. Scientists are still determining whether solid ground lies beneath the snow and ice.
John Gibson of the Australian Antarctic Division believes the feature is likely an ice island. He describes it as a substantial, heavy sheet of ice resting on an underwater summit. The description echoes other ice islands such as Bowman Island, as Gibson stated in a release. He notes this ice island is self-sustaining, with snowfall accumulating on the surface offsetting some melting beneath the water. If snowfall declines, the ice island could thin and drift away. The unnamed feature might become a permanent landscape element, but could someday detach from bedrock and transform into an iceberg.
Because nobody was present to observe this new geographic feature, experts propose direct verification through a field expedition to assess the bedrock below. As one glaciologist explained, radar could be used to measure ice thickness, and spacecraft data shows the surface remains high above sea level. If there were no bedrock at or above sea level, a large ice structure would form a distinct cone in the data.
Whether considered a traditional island or an ice island, this feature is part of a growing group of similar elements no longer embedded in Antarctica’s floating ice. In 2019, the U.S. Geographic Names Board recognized Icebreaker Island, which separated from Larsen B along the Antarctic Peninsula in 1996. In 2020, researchers aboard a voyage identified a small, rocky, ice-covered island potentially linked to Pine Island Glacier’s ice shelf.
Experts anticipate that the ongoing retreat of glaciers and sea ice will continue to reveal such isolated features for years to come. This ongoing exploration is likely to illuminate more about how these ice bodies interact with the underlying geology and ocean. The discovery adds to a growing understanding of how the Antarctic coastline is evolving in a warming world.
Reference work: Earth Observatory NASA image series on the ice-lost island discovery.
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