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Scientists discovered an ancient river landscape preserved under the East Antarctic Ice Sheet – Times of India

NEW DELHI: Global warming may uncover an ancient river landscape hidden beneath the East Antarctic Ice Sheet for a million years, according to a recent study.
Although this ancient landscape remains untouched by the massive ice retreat in the region, projected climate warming could expose it in the future, as per a paper published on Tuesday in Nature Communications.
The author of the study and who researches ice sheet behavior, long-term, and landscape evolution at Durham University in the UK, Stewart Jamieson, told ABC News that for about 34 million years, ice has covered Antarctica. Before that, the continent had a comparatively warm climate similar to modern-day southern South America, such as the Patagonia region in Argentina and Chile.
According to Jamieson, at one time, there was evidence that Antarctica had tropical vegetation, including palm trees.
Jamieson said, Scientists have recently found a vast landscape shaped by ancient rivers in Antarctica. This landscape is located in the Aurora-Schmidt basins, which are inland from the Denman and Totten glaciers. About 34 to 60 million years ago, a river flowed from the middle of the continent toward the coast. During this period, other continents like Australia and India were breaking away from Antarctica and the Gondwana supercontinent.
The landscape was estimated to have been buried beneath the ice shelf for between 14 million and 34 million years, which was found using satellites and ice-penetrating radar, reported ABC News.
Prior to this technique, researchers knew a lot about the topography, using the radar-equipped planes to study and see the landscape beneath the ice sheet, Jamieson said.
But the planes couldn’t cover all areas, resulting in significant gaps in the measurements taken by the planes, he noted.
According to the study, the river-carved landscape consists of three upland blocks separated by deep troughs, located only about 217 miles from the ice sheet edge. These blocks took their form before the ice covered the region, back when rivers flowed to a coastline formed during the breakup of the Gondwana supercontinent.
As Antarctica gradually cooled, small glaciers started to form in the river valleys, Jamieson said. However, a significant cooling event occurred, causing the East Antarctic Ice Sheet to expand and cover the entire continent, effectively burying the river landscape beneath it, he added.
Jamieson said, “When that happens, it’s basically like switching on a freezer for our little landscape, and it kind of freezes it in time,” as per ABC News.
When the Gondwana supercontinent broke apart, it also led to the formation of valleys between the upland blocks. These valleys developed before the uplands were covered by glaciers, according to the researchers.
The discovery suggests that ice has remained stable in this region for millions of years, despite warming periods. Researchers hope to obtain samples of sediment and rock to learn more about the ancient vegetation and ecosystem that existed while the river was active, Jamieson said.
However, climate warming could lead to ice retreat in the region for the first time in at least 14 million years, according to the study.
Western Antarctica has seen the most melting on the continent, particularly the “Doomsday Glacier,” which, if completely melted, could cause a 10-foot rise in sea levels. In contrast, the ice shelf in East Antarctica holds the potential for a sea level rise equivalent to 60 meters, or almost 200 feet, according to the study.
A recent study suggests that it might be too late to stop significant melting in western Antarctica, even with the most aggressive efforts to mitigate it, as reported earlier this month.
(With input from agencies)

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