GEOGRAPHY

Ancient river landforms are found under the East Antarctic ice sheet


British scientists have discovered ancient river-eroded landforms under the East Antarctic ice sheet. Continental-scale ice retreat hasn’t touched the newly discovered feature for at least 14 million years, but in the study published today in Nature Communications, scientists believe that could change as the projected climate warms.

The earth’s climate is changing rapidly, and it is about to reach the typical temperature of 34 million ~ 14 million years ago (3 °C ~ 7 °C higher than now). Understanding how the Antarctic ice sheet changed in the past can help inform how it might evolve in the future of continued climate change. This is important because the ice sheet contains the equivalent of about 60 metres of potential sea level rise. Ice detection radar can be used to observe subglacial landscapes and determine how the ice sheet changed before the satellite era.

Stewart Jamieson and colleagues at Durham University used satellite and radar to analyze the landforms under the East Antarctic ice sheet in the Aurora-Schmidt Basin, inland from the Danman and Totten glaciers. They found that the landscape consisted of three river-eroded plateaus, separated by deep troughs, just 350 kilometers from the edge of the ice sheet.

The formation of these massifs predates the formation of glaciers, when rivers flowed through the area to the coastline carved out during the disintegration of the Gondwana supercontinent. The disintegration of the Gondwana supercontinent also led to the formation of valleys between the highlands, which only then began to be covered by glaciers. Jamieson believes that the ice covered in this area has remained largely stable for millions of years, although there have been warm periods during the interval.

Researchers say warming could lead to glacier retreat into the region for the first time in at least 14 million years, and these findings improve understanding of the past history of glaciers in the East Antarctic ice sheet. (Source: Feng Weiwei, China Science News)

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Uncover the ice sheet and show the study sites under the ice. Photo by Stewart Jamieson

Related paper information:https://doi.org/10.1038/s41467-023-42152-2



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