Employing new ice-penetrating radar over a key area of Earth's largest body of ice, scientists are able to see a vast expanse of mountainous terrain and fjords that were carved by flowing glaciers when sea levels were some 200 feet higher than today.
The shape of this landscape beneath a broad region of the East Antarctic Ice Sheet known as the Aurora Subglacial Basin is critically valuable to researchers trying to figure out how quickly -- and when -- the ice burying this land will respond to rising air and sea temperatures in a warming world.
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The first map of this previously uncharted region has been developed by an international research team led by geophysicist Duncan A. Young of the University of Texas at Austin and published this week in the journal Nature. Collaborators included British and Australian scientists.
"We knew almost nothing about what was going on, or could go on, under this part of the ice sheet and now we've opened it up and made is real," Young said in a statement released by the University. Co-author Donald Blankenship said the subglacial basin was studied "because it may represent the weak underbelly" of the largest potential source of sea-level rise.
The dominant feature of the region is a very large low-lying trough -- more than a kilometer below sea level -- that runs at a right angle to the modern shoreline. Branching off of this trough are large fjords that were sculpted by outlet glaciers when temperatures were warmer than today and the shoreline of the region was much farther inland, the researchers report.
In a separate evaluation of the study, Sandra Passchier, a polar ice specialist at Montclair State University, New Jersey, calls attention to this submarine, "landward-dipping" topography.
"In this configuration, ice sheets are susceptible to unstable retreat," she wrote, "and the resulting ice-loss could contribute to accelerated sea-level rise."
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The ice sheet and the flow of the glaciers moved back and forth of this low-lying basin more than once and sea level rose and fell more dramatically than in recent ages, although researchers are not sure of the time scales involved. Young and colleagues give an age of between 34 million and 14 million years, while Passchier points to evidence for a more recent time of global warmth 5 million to 3 million years ago.
IMAGE: Inset shows the location of the Aurora Subglacial Basin in Antarctica. CREDIT: University of Texas, Austin
Tags: Antarctica, Climate Change, Geophysics, Glaciers, Global Warming
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