Scientists discover long-lost giant rivers that flowed across Antarctica up to 80 million years ago
Scientists have discovered a long lost landscape that has been kept under the Antarctic glacial cap for 30 million years.
Erosion by ancient rivers seems to have sculpted large flat surfaces under the ice in eastern Antarctic between 80 million and 34 million years. Understand how these characteristics have formed and how they continue to affect the landscape could help refine the predictions of the loss of future ice, the researchers reported on July 11 in the journal Nature geoscience.
“We have long been intrigued and perplexed on fragments of flat” evidence of “flat” landscapes under the glacial caps of Antarctica “, co-author of the study Neil RossA geophysicist at Newcastle University in the United Kingdom, said in a statement. “This study brings together data from the skipping saw together, to reveal the overview: how these old surfaces have formed, their role in determining the current ice flow and their possible influence on the way in which the glacial cap of the eastern Antarctic will evolve in a warming world.”
If the ice cap of the eastern Antarctic was to melt entirely, it could increase the world’s sea level over 160 feet (50 meters). But predict with precision how the glacial cap could melt in the coming years obliges scientists to know its past behavior and the conditions at its base.
In the new study, the researchers used radar data of four previous surveys to map the shape of the rocky substratum under ice.
“When we examine the radar images of the under-gelled topography of this region, these remarkably flat areas started to go out almost wherever we looked at”, co-author of the study Guy PaxmanA polar geophysicist at the University of Durham in the United Kingdom, in the press release. “The flat surfaces we have found have managed to survive relatively intact for more than 30 million years, indicating that parts of the ice cap has preserved rather than eroding the landscape.”
The flat expanses, which were interspersed with deep hollows, covered a section of 2,175 miles (3,500 kilometers) of the coast of eastern Antarctica. They probably formed before the existence of the ice cap of the Eastern Antarctica but after the Supercontinent Gondwana (which contained modern times AntarcticAustralia, Africa and India) separated.
This helped researchers go out with the flat sections between 80 and 34 million years old.
At the top of these flat surfaces, the Antarctic ice moves quite slowly. But in the hollows between them, the ice flows much faster. The fusion may have sculpted these hollows by crossing natural dips as the glacial cap of the oriental Antarctic has expanded millions of years ago.
The slow ice flow above flat surfaces could be to regulate the loss of ice in the continent, the researchers wrote in the study. Additional research, such as obtaining and analyzing rock samples under the ice, could refine projections of the loss of future ice and the elevation of the sea level.
“Information such as the form and geology of newly mapped surfaces will help improve our understanding of how ice flows to the edge of eastern Antarctic,” said Paxman. “This will in turn help to facilitate the forecast of the way in which the ice cap of the eastern Antarctic could affect the sea level at different levels of global warming in the future.”
