Remains of a huge, ancient lake have been found under Greenland, buried under a sheet of ice in the northwest of the country and estimated to be millions, if not thousands, years old, scientists say.
The giant ‘fossil lake bed’ is a phenomenon that scientists have never seen before in this part of the world, as we know it, but the Greenland ice sheet (the world’s second largest after Antarctica, full of hidden mysteries) is under its fixed identification, while Mass flow at an alarming rate.
Last year, scientists discovered more than 50 subglacial lakes beneath the Greenland ice sheet: liquid water bodies trapped between bedrock and ice sheet overhead.
The new discovery is of a different nature: an ancient lake basin, a long dry and now silt-filled prehistoric one – 1.2 kilometers (three-quarters of a mile) thick – and then another 1.8 kilometers covered covered loose green rock. Ice.
(Accepted from Columbia University, Paxman et al., EPSL, 2020)
Above: Lake basin (red outline) fed by ancient currents (blue).
Researchers say the lake was formed a long time ago, but the area would be free of ice, and the basin would support a monumental lake with a large area of about 100 square kilometers (2,7411 square miles).
That U.S. The states are about the same size as the combined area of Delaware and Rhode Island, and this vast lake contains about 80,880 cubic kilometers (1) cubic miles of water, fed by a network of at least 18 ancient streams that once existed. To the north of the bed of the lake, there is an escarpment flowing.
There is no way to know how old this lake is right now (or if it has been flooded and flooded many times), we will find out if we can now analyze the nail rock material inside the basin: a huge time capsule saved The silt that can give us clues a little bit earlier about Greenland’s environment.
“This could be an important repository of information, in a landscape that is now completely hidden and inaccessible,” says Guy Paxman, a lead researcher at the University of Columbia and a snow-geographer.
“If we could reach that silt, it would be able to tell us if the ice was present or absent.”
The huge lake bed – the so-called ‘Camp Century Basin’ in the context of the nearby historic historical research base – was identified by observations from NASA’s Operation Icebridge mission, which is an aerial survey of the world’s polar regions.
During flights over the Greenland ice sheet, the team mapped the subglacial geomorphology beneath the ice using a range of devices for measuring radar, gravity and magnetic data. These dimensions outline the massive loose mass of the silt infill, made of less gnse and less magnetic material than the hard rocks around it.
It is possible, the team believes, that the lake was formed as a result of bedrock displacement due to a fault line below the bottom, which is now inactive. Alternatively, the shape of the basin can be carved over time due to glacial erosion.
In both cases, researchers believe that the ancient basin has an important sediment record, and if we can dig it out and drill down an owl to analyze it, it could indicate that the area was ice-free or covered with ice. , Then reveals the obstacles. Greenland offers an insight into the extent of the ice sheet, and the region’s past climate and environmental conditions.
The secre rocks that can tell us about polar climate change in the ancient past can be important information to explain what is happening in the world right now.
“We’re working to understand and understand how the Greenland ice sheet behaved in the past,” says Paxman. “It’s important if we are to understand how it will behave in future decades.”
These findings are reported Earth and Planetary Science Letters.
.
