Heat source under Antarctica melting ice sheet

A new study by NASA, Study Bolsters Theory of Heat Source Under West Antarctica, adds evidence that a geothermal heat source called a mantle plume lies deep below Antarctica's Marie Byrd Land.

Hélène Seroussi and Erik Ivins of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, studied this mantle plume idea through numerical modeling, since getting direct measurements from under the ice is hard. The team found that the geothermal heat emitted by the Antarctic mantle plume is up to 150 milliwatts per square meter.

According to the research paper published in the Journal of Geophysical Research: Solid Earth, the researchers used ISSM to study the natural sources of heating and heat transfer, including freezing, melting, the volume of liquid water, friction, and other processes.

Illustration of flowing water under the Antarctic ice sheet.

Now, scientists from NASA's Jet Propulsion Laboratory have created advanced numerical models to show how much heat would need to exist beneath the ice to account for their observations-including the dome and the giant subsurface rivers and lakes we know are present on Antarctica's bedrock.

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Scientists believe that understanding the sources and future of the meltwater under West Antarctica could help estimate the rate at which ice may be lost to the ocean in the future. This rise and fall motion of the ice surface also helps the scientists to estimate the quantity of water at certain places.

Mantle plumes are thought to be narrow streams of hot rock rising through Earth's mantle and spreading out like a mushroom cap under the crust.

After that, they simulated a number of different scenarios for the size and location of a possible mantle plume, since both those factors were unknown, and compared the effects with observations of Antarctic melting, as recorded by satellites in space. 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). The buoyancy of the material in the streams causes the Earth's crust to bulge upward. We use a simple analytical mantle plume parameterization to produce geothermal heat flux at the base of the ice sheet.

Concluding, the team say the Marie Byrd Land mantle plume formed 50-110 million years ago-long before the land above was hidden by ice. But by the end of the last ice age, around 11,000 years ago, the ice sheets faced rapid, sustained loss in its volume. For comparison, over the entirety of Yellowstone National Park the underground heat measures an average of 200 milliwatts per square meter.

Helene Seroussi says that she felt excited about hearing the idea of a heat source under ice sheets.

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