NASA Discovers Supervolcano Mantle Plume Melting Antarctica From Below

© Provided by IBT Media (UK) Marie_Byrd_Land,_West_Antarctica_by_NASA

Regional volcanic activity under Marie Byrd Land may be down to a super volcano hidden under the ice sheet. For 30 years, scientists have suggested that a mantle plume may exist under the ice, and its presence would explain volcanic activity in the area, with lakes filling and draining causing the ice thousands of feet above to rise and fall, sometimes by as much as 20 feet, as well as a dome feature that exists there. However, there was no evidence to support this idea, until now, that is, with scientists from NASA’s Jet Propulsion Laboratory having 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. Study author Hélène Seroussi, from JPL, thought the idea was crazy, as she didn’t see how we could have that amount of heat and still have ice on top of it. To this end, in study published in the Journal of Geophysical Research: Solid Earth, Seroussi and colleagues looked at one of the most well studied magma plumes on Earth, the Yellowstone hotspot. The team then developed a mantle plume model to look at how much geothermal heat would be needed to explain away what they observed on Marie Byrd Land. They then used the Ice Sheet System Model (ISSM), which shows the physics of ice sheets, to look at the natural sources of heating and heat transport. This model enabled researchers to build a research grid and measure how much melt rate was allowable, meaning they could test out different scenarios of how much heat was being produced deep beneath the ice. 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 heat generated under Yellowstone National Park, on average, is 200 milliwatts per square meter. Scientists also found one area where the heat flow must be at least 150-180 milliwatts per square meter—but data suggests mantle heat at this location comes from a rift—a fracture in the Earth’s crust where heat can rise up. 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. Heat from it, they say, has an “important local impact” on the ice sheet—and understanding these processes will allow researchers to work out what will happen to it in the future.

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