A Massive Heat Source Is Melting Antarctica Ice Sheet From Below

Posted: Nov 10 2017, 5:36am CST | by , Updated: Nov 10 2017, 5:44am CST, in News | Latest Science News

 
A massive Heat Source is Melting Antarctica Ice Sheet from Below
Credits: NSF/Zina Deretsky

NASA finds a strong evidence for a mantle plume deep below Antarctica's Marie Byrd Land

NASA scientists have uncovered a massive geothermal heat source beneath the West Antarctic ice sheet and it could possibly explain the rapid melting of ice that occurred in the region some 11,000 years ago. The heat source could also help indentify the cause of the unstable condition of Antarctica today.

Antarctica is a region of the world particularly vulnerable to climate change and the ice loss here could have a significant effect on sea level rise. Understanding the sources of the meltwater under West Antarctica will help determine the rate at which ice may be lost to the ocean in the future.

Some 30 years ago, a University of Colorado Denver scientist suggested that West Antarctica's Marie Byrd Land harbors a plume deep inside its interior that is causing intense volcanic activity in the region. Now, the very latest seismic images from NASA also support that theory. By using the Ice Sheet System Model (ISSM) (a numerical depiction of the physics of ice sheets developed by scientists at JPL and the University of California, Irvine), researchers attempted to identify the natural sources of heating and heat transport from freezing, melting and liquid water in Antarctica.

To confirm that the results were accurate, researchers utilized the observations of changes in the altitude of the ice sheet surface made by NASA's IceSat satellite and airborne Operation IceBridge campaign. Since the location and size of the possible mantle plume were not known, they had to cover a vast amount of area in order to identify the heat source.

Researchers calculated that the rate of the transfer of energy from the mantle plume must be no more than 150 milliwatts per square meter. For comparison, in U.S. regions with no volcanic activity, the heat flux from Earth's mantle is 40 to 60 milliwatts. Under Yellowstone’s volcanic hot spot, the heat from below is about 200 milliwatts per square meter. However individual geothermal features such as geysers are much hotter than that.

A heat flow higher than 150 milliwatts per square was detected nowhere, except in one location: an area inland of the Ross Sea known for intense flows of water. The mantle plume of Ross Sea located in Marie Byrd Land has been around for over 50 million years, long before the West Antarctic ice sheet came into existence

At the end of the last ice age around 11,000 years ago, the ice sheet went through a period of an unprecedented ice loss due to changes in global weather patterns. As a result, the sea level rose and pushed warm water close to the ice sheet—just as is happening today.

The presence of mantle plume underneath Marie Byrd Land is not only the best explanation of rapid melting in West Antarctica thousands of years ago; it could have serious implications for studying the recent changes in the region.

Source: NASA

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Hira Bashir covers daily affairs around the world.

 

 

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