This illustration exhibits the place water rests and flows underneath the Antarctic ice, with blue dots indicating lakes and features indicating rivers.
Credit: Credit: NSF/Zina Deretsky
Imagine drifting over Antarctica’s icy expanse. A white continent extends beneath you, and it is smothered in sufficient frozen water to drown each shoreline on the earth in a 216-foot (66 meters) wave if it have been to soften. But scientists now consider that, deep beneath nearly 1.2 miles (2 kilometers) of ice and a comparatively skinny slice of rocky crust, one area of the frozen continent hides a column of red-hot magma, straining towards the floor, in line with a brand new examine.
Usually, magma nears the floor solely on the edges of tectonic plates. And West Antarctica’s Marie Byrd Land, the place the plume is suspected to exist, is much from any such border areas. However, there are locations on the earth the place magma reaches towards the floor removed from any tectonic border areas, NASA scientists mentioned in a Nov. 7 badertion. Yellowstone National Park is one. Hawaii is one other. All that magma pushes in opposition to the crust in these elements of the world, inflicting it to bulge and pumping warmth up by means of the bottom.
That warmth supplied scientists the primary clues that the Antarctic plume exists. [Photo Album: Antarctica, Iceberg Maker]
Despite its obvious icy stillness, Antarctica is alive with movement. Huge plenty of frozen water slip, slide and grind with monumental strain in opposition to the continent beneath, their fixed movement lubricated by a posh system of rivers and lakes beneath the ice.
But in Marie Byrd Land, researchers discovered much more of that exercise than the identified regional warmth sources might clarify. Something else was cooking the ice shelf. About 30 years in the past, researchers first started to suspect magma plume is perhaps the trigger, given the domed form of the crust in that space.
Now, scientists know for positive.
Study researchers Hélène Seroussi and Erik Ivins of NASA’s Jet Propulsion Laboratory constructed a mannequin of all of the identified melting and freezing underneath the ice within the area. Researchers do not have probes underneath the ice, however they’ll detect the exercise due to cautious measurements of the rise and fall of the floor from NASA’s ICESat satellite tv for pc and IceBridge flyover missions. [Extreme Antarctica: Amazing Photos of Lake Ellsworth]
Their mannequin confirmed the existence of a magma plume pumping about 150 milliwatts per sq. meter (or about 11 sq. ft) of warmth as much as the floor, and peaking at as a lot as 180 milliwatts per sq. meter in a area the place a rift within the crust might exist. (A milliwatt is one-thousandth of a watt.) For comparability, a typical stretch of land within the United States will get about 40 to 60 milliwatts per sq. meter of geothermal warmth, and Yellowstone will get about 200 milliwatts per sq. meter.
This magma plume is not another potential reason for current upticks in melting alongside the West Antarctic Ice Sheet attributed to human-generated local weather change. The plume is much older than the current interval of atmospheric warming; certainly, at 50 million to 110 million years previous, it is older than our species and the West Antarctic Ice Sheet itself. The plume has been an element within the ice sheet’s conduct all through its historical past, and up to date surges in melting are the results of all the extra warmth people have pumped into it.
The examine was printed on-line Sept. four within the Journal of Geophysical Research: Solid Earth.
Originally printed on Live Science.