Geothermal Heat Source Under Antarctica Might Help Explain Ice Shelf Instability, NASA Researchers Say

Pam Wright
Published: November 8, 2017

NASA researchers have found new evidence that an ancient geothermal heat source might help explain how rivers and lakes form beneath the West Antarctic ice sheet.

According to a press release, an underground mantle plume deep beneath Antarctica's Marie Byrd Land likely formed some 50 to 110 million years ago and may help explain some of the instability plaguing the ice shelf.

Mantle plumes are believed to be narrow streams of hot rock, which spread like a "mushroom cap" beneath Earth’s surface, NASA also said. The buoyancy of the material in the streams causes the Earth's crust to bulge upward.

A University of Colorado scientist first suggested that a geothermal heat source was responsible for regional volcanic activity and a topographic dome feature in the area some 30 years ago.

(MORE: Large Iceberg Seen Breaking Off Antarctic Glacier)

Illustration of flowing water under the Antarctic ice sheet. Blue dots indicate lakes, lines show rivers. Marie Byrd Land is part of the bulging "elbow" leading to the Antarctic Peninsula, left center.
(NSF/Zina DeretskyClose)

Hélène Seroussi of NASA's Jet Propulsion Laboratory in Pasadena, California, said when she first heard the idea, she "thought it was crazy."

"I didn't see how we could have that amount of heat and still have ice on top of it," she said.

However, recent seismic imaging seems to confirm the hypothesis. Using numerical modeling coupled with the imaging enabled the scientists to find one particular "hot spot" presumed to be the massive heat source.

Rivers and lakes, the largest of which is the size of Lake Erie, lie beneath Antarctica and drain meltwater into the ocean. At times, the lakes fill and drain so rapidly that they can cause the ice surface thousands of feet above to rise and fall by as much as 20 feet.

The scientists note in the study published this week in the Journal of Geophysical Research that mantle plumes are not new phenomena. However, the latest data could help researchers better estimate future ice loss in the area because "the stability of an ice sheet is closely related to how much water lubricates it from below, allowing glaciers to slide more easily," the NASA press release noted.


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