Magma May Be Melting Greenland Ice 

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Magma May Be Melting Greenland Ice

13 Dec 07 - Scientists have found at least one natural-magma hotspot under the northeast corner of the Greenland Ice Sheet where heat from Earth’s insides could seep through, scientists will report this week at a meeting of the American Geophysical Union.

The corner of Greenland where the hotspot was found had no known ice streams - the rivers of ice that run through the main ice sheet and out to sea - until one was discovered in 1991. What exactly caused the stream to form was uncertain.

"Ice streams have to have some reason for being there," said lead scientist Ralph von Frese of Ohio State University, "and it’s pretty surprising to suddenly see one in the middle of the ice sheet."

The newly discovered hotspot, an area where Earth’s crust is thinner, allowing hot magma from Earth's mantle to come closer to the surface, is just below the ice sheet and could have caused it to form, von Frese and his team suggest. "Where the crust is thicker, things are cooler, and where it’s thinner, things are warmer," von Frese explained.

What caused the hotspot to suddenly form is another mystery. "It could be that there’s a volcano down there," von Frese said, "but we think it’s probably just the way the heat is being distributed by the rock topography at the base of the ice."

               I’ve been saying for years that underwater volcanoes are heating 
               the seas and melting the ice in the the Arctic and Antarctica. This
              new discovery provides true validation.

See entire article by Andrea Thompson:
Thanks to Dan Scott, Bob Wentworth, Shay Fowler and Johnny Zornes for this link

* * * 
Here's are excerpts from another article on the same discovery:

Earth's heat melting Greenland ice

The researchers don't yet know how warm the hotspot is. But if it is warm enough to melt the ice above it even a little, it could be lubricating the base of the ice sheet and enabling the ice to slide more rapidly out to sea.

"Crustal heat flow is still one of the unknowns -- and it's a fairly significant one, according to our preliminary results," said Ralph von Frese, leader of the project and a professor of earth sciences at Ohio State University. 

von Frese's team combined gravity measurements of the area taken by a Naval Research Laboratory aircraft with airborne radar measurements taken by research partners at the University of Kansas. The combined map revealed changes in mass beneath the Earth's crust, and the topography of the crust where it meets the ice sheet.

Below the crust is the mantle, the partially molten rocky layer that surrounds the Earth's core. The crust varies in thickness, but is usually tens of miles thick. Even so, the mantle is so hot that temperatures just a few miles deep in the crust reach hundreds of degrees Fahrenheit, von Frese explained.

The ice thickness, the temperature at the base of the ice, and ground topography all contribute to the forming of an ice stream -- a river of ice that flows within a larger ice sheet. In recent years, Greenland ice streams have been carrying ice out to sea faster, and ice cover on the island has been diminishing.

The ice sheet in northeast Greenland had no known ice streams until 1991, when satellites spied one for the first time. Dubbed the Northeastern Greenland Ice Stream, it carries ice nearly 400 miles, from the deepest interior of the island out to the Greenland Sea.

"Recent observations indicate that the Greenland Ice Sheet is much more active than we ever believed," said collaborator Kees van der Veen of the University of Kansas. "There have been rapid changes in outlet glaciers, for example. Such behavior is critically linked to conditions at the ice bed. Geothermal heat is an important factor, but until now, our models have not included spatial variations in heat, such as this hotspot.

"Our map is the first attempt at quantifying spatial variations in geo-heat under Greenland -- and it explains why the Northeast Greenland Ice Stream is where it is," van der Veen added.
See entire article:
Thanks to Steve Turney in Winnipeg, Manitoba, for this link.



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