A moulin, or drainage passage, within the crater on the Roi Baudouin ice shelf in Antarctica.
A “crater” in Antarctica, once considered the work of a meteorite impact is actually the result of the melting of ice, new research finds.
The hole, which is in the king Baudouin ice shelf in East Antarctica, is a collapsed more — a cavity formed as a lake of meltwater discharged with a “moulin”, an almost vertical drainage passage through the ice beneath it, the researchers found on a trip to the area in January 2016.
“That was a big surprise,” Stef Lhermitte, an earth science researcher at the technical University of Delft in the Netherlands and at the University of Leuven in Belgium, said in a statement. “Moulins usually be observed in Greenland. And we certainly never see them on a ice shelf.” [See Photos of the Meltwater Lake Crater in Antarctica]
More From LiveScience
Images of Melt: Earth’s Vanishing Ice
Antarctic Album: Drilling Into Subglacial Lake Whillans
25 Strangest Sights on Google Earth
Combining their work with satellite data and climate modeling, the researchers found that East Antarctica is more vulnerable to melting than was previously realized. Warm winds of the region blow away the snow cover, which darken the surface of the ice, the team reported Dec. 12 in the journal Nature Climate Change. Dark surfaces absorb more heat from the sun than the lighter planes, so they are more likely to melt. These floating ice sheets will not contribute a lot to the increase of the sea level — if they are already in the ocean, but they provide an important stand against the power of the land-based ice of continental Antarctica in the ocean.
East Antarctica is a mysterious place when it comes to climate change. The region is gaining ice as a result of an increase in snow accumulation, according to 2015 research. Global warming can increase snowfall by stimulating the amount of moisture in the air (warm air more moisture than cold).
The Roi Baudouin crater was more mysterious still. It was satellite images going back to at least 1989, researchers said, but was first noted on a large scale in January 2015. Scientists initially reported that it was a meteorite crater, maybe the result of a space rock that exploded above Antarctica in 2004. But scientists soon questioned whether the 2-meter-wide circle was really a meteorite. Many suspect it was the result of the melting of ice.
Jan Lenaerts, a climate researcher at the University of Utrecht in the Netherlands and at the University of Leuven, was one of the meteorite skeptics.
“My reaction was: ‘In that area? Then it is certainly not a meteorite; it is a proof of the strong melt, ” he said in a statement.
The new study confirms that suspicion. During their fieldwork on the southern continent, researchers also discovered many other meltwater lakes beneath the surface of the king Baudouin ice shelf.
“The amount of meltwater varies greatly from year to year, but it clearly increases during warm years,” Lhermitte said.
Earlier research had shown that West Antarctica is highly sensitive to climate change, Lenaerts said in the statement.
“Our research now suggests that the much larger East Antarctica ice sheet is also very vulnerable,” Lenaerts said.
Original article on Live Science .