Researchers used ice-penetrating radar to survey the topography of Antarctica from aeroplanes
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Preserved Ancient Landscape
A recent exploration using ice-penetrating radar has discovered evidence of an ancient landscape, shaped by rivers and glaciers, beneath the East Antarctic ice sheet. This finding suggests that this region of Antarctica may have been covered in ice for more than 30 million years, providing valuable insights into how the ice will respond to climate change in the future.
Details of the Hidden Landscape
Although most of Antarctica’s geological features are hidden beneath a thick ice sheet, radar measurements have offered a glimpse into its broad contours. However, the finer details of this hidden landscape have remained obscure, until now.
Researchers led by Stewart Jamieson from Durham University in the UK analyzed satellite radar measurements and compared them with direct measurements from ice-penetrating radar recorded during aerial surveys. This comparison revealed a distinct region, called “Highland A,” with three blocks of land separated by fjord-like troughs. If the ice were removed, the topography would resemble the peaks and valleys of the Lake District in the UK.
A Geological History
The researchers propose that these features tell a geological history dating back to the separation of Antarctica from the Gondwana supercontinent around 180 million years ago. They suggest that rivers flowing through rifts created by the break-up shaped the fjord-like troughs, which were subsequently carved out further by glaciers formed during a cooling period around 34 million years ago.
The preservation of Highland A is attributed to the formation of a cold base beneath the ice sheet, which locked onto the rock and prevented erosion. According to Jamieson, this suggests that the region has been covered in ice for at least the past 14 million years, if not 34 million years. The stability of the ice sheet in this area provides valuable information for understanding the stability of East Antarctica as a whole.
Implications for Climate Change
While most research on melting ice in Antarctica has focused on the West Antarctic ice sheet, understanding the stability of the East Antarctic ice sheet is crucial. Mathieu Morlighem from Dartmouth University suggests that the findings of this study could improve models of how the ice sheet will respond to rising temperatures due to climate change.
However, Sean Gulik from the University of Texas at Austin cautions that there may have been fluctuations in the ice sheet as recently as 1.5 million years ago, indicating a potential sensitivity to today’s warming. The limited knowledge about what lies below the ice sheet underscores the need for further exploration and understanding.
