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Study bolsters theory of heat source under Antarctica
09 November 2017, 02:07 | Justin Tyler
Mysterious geothermal 'mantle plume' under Antarctica is heating its ice sheet, NASA study confirms
The Marie Byrd Land mantle plume formed 50 to 110 million years ago, long before the West Antarctic ice sheet came into existence.
Hélène Seroussi of NASA's Jet Propulsion Laboratory in Pasadena, California, said when she first heard the idea, she "thought it was insane". The current research says that this heating source is the cause of ice melting and creation of lakes and rivers beneath ice sheets.
Their findings showed that generally, the energy being generated by the mantle plume is no more than 150 milliwatts per square meter-any more would result in too much melting.
The amount of liquid water beneath an ice sheet affects its stability.
Although the heat source isn't a new or increasing threat to the West Antarctic ice sheet, it could help explain why the ice sheet collapsed rapidly some 11,000 years ago and why it's so unstable today, Seroussi said. The heat source is called a mantle plume, and its role in affecting volcanic activity and topographic features on Antarctica was first theorized about 30 years ago by a scientist at the University of Colorado, Denver.
Helene Seroussi and Erik Ivins, the research scientists of NASA's Jet Propulsion Laboratory in Pasadena, California got their paper, named Influence of a West Antarctic mantle plume on ice sheet basal conditions, published in the Journal of Geophysical Research: Solid Earth. This rise and fall motion of the ice surface also helps the scientists to estimate the quantity of water at certain places. The rapid filling and draining of lakes and rivers in the Antarctica result in rising or falling of ice sheaths to almost 20 feet (6 meters).
Mantle plumes are areas of hot, upwelling mantle and are thought to be the cause of volcanic centers known as hotspots.
To assure the model was realistic, the scientists drew on observations of changes in the altitude of the ice sheet surface made by NASA's IceSat satellite and airborne Operation IceBridge campaign.
Mantle plumes, first theorized in the 1970s, "are thought to be narrow streams of hot rock rising through Earth's mantle and spreading out like a mushroom cap under the crust", a statement Tuesday on NASA's website said.
As the material is buoyant, it pushes the crust upward. Whereas, the Yellowstone National Park in the U.S. which is well known as a geothermal hotspot has an average heat flux of 200 milliwatts per square meter over the entire park, even though individual geothermal features like geysers will be much hotter.
A mantle plume producing nearly as much heat as Yellowstone supervolcano appears to be melting part of West Antarctica from beneath. Ivins and Seroussi suggest the Marie Byrd Land mantle plume could have accelerated this rapid ice loss in this region.