Geophysicists have discovered the ancient landscape of Antarctica with huge rivers and wide valleys, which has been buried under a thick layer of ice for the last 30 million years.
The ancient rivers formed vast plains between 80 and 34 million years ago. Understanding how these geological formations formed and how influence the current climate. The newly discovered data may help scientists refine their forecasts of further ice sheet melting.
«We have long been intrigued and puzzled by fragments of evidence for the existence of «flat» landscapes beneath the Antarctic Ice Sheet. This study brings together the pieces of data to build a bigger picture: how these ancient surfaces formed, what their role is in determining modern ice movement, and what their possible impact is on the evolution of the East Antarctic Ice Sheet under global warming», — explains study co-author Neil Ross, a geophysicist at Newcastle University.
If the East Antarctic Ice Sheet completely melt, global sea levels could rise by more than 50 meters. However, in order to accurately predict the amount of ice that could melt, scientists need to know how these processes have occurred in the past. In the new study, British scientists used radar data from four previous studies to create a map of the relief beneath the ice layer.
«When we studied radar images of the subglacial terrain in this region, these surprisingly flat surfaces began to appear almost everywhere we looked. The flat surfaces we found have remained relatively untouched for more than 30 million years, suggesting that parts of the ice sheet preserved the landscape rather than destroying it», — said the study’s co-author, is a geophysicist at Durham University, Guy Paxman.
These plains, which also contain deep depressions, covered the coast of East Antarctica for a distance of up to 3.5 thousand kilometers. They were probably formed before the appearance of the East Antarctic Ice Sheet, but after the destruction of the supercontinent Gondwana.
On these flat surfaces antarctic ice is moving very slowly. However In the troughs between them, the ice moves much faster. Meltwater may have formed these troughs by flowing through natural depressions as the East Antarctic Ice Sheet expanded millions of years ago.
The slow movement of ice on flat surfaces can help regulate ice melt on the continent. Further research, such as obtaining and analyzing rock samples from under the ice, will allow us to refine our predictions of future ice loss and sea level rise.
The results of the study are published in Nature Geoscience
Source: LiveScience
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