Greenland holds many secrets that are still mysterious hidden deep in the ice sheet below. There are a number of secret structures in it.
Fridtjof Nansen, leader of the first expedition across Greenland, once described what he found at the North Pole as a great adventure in an icy world truly deep and pure at infinity. Unfortunately, Nansen who made his journey in 1888 couldn't figure out the wonders hidden beneath the icy landscape beneath his skis.
Now, thanks to radar and other technology, the part of Greenland beneath the 3,000-metre-thick ice sheet is in focus. These new tools reveal complex and unseen landscapes that hold clues about the Arctic's past and future. Here are some of the mysterious structures detected beneath the Greenland ice sheet.
The longest canyon in the world
The Greenland ice sheet hides the world's longest canyon. Discovered in 2013, the canyon stretches 740 kilometers from the highest point in central Greenland to the Petermann Glacier on the northwest coast. That's much longer than the 308 496 km Yarlung Tsangpo Grand Canyon, the longest canyon on Earth that we can actually see.
The canyon beneath the Greenland ice sheet is up to 800 m deep in places, and 10 km wide. By comparison, the Grand Canyon in Arizona is on average about 1.6 km deep and 16 km wide.
Parts of the canyon can drain meltwater from beneath the ice sheet into the ocean. This canyon may have formed before being covered by a layer of ice and was once a conduit for the flow of a large river.
Invisible mountain
Canyons aren't the only rugged part of Greenland's icy landscape. Decades of mapping the island with ice-penetrating radar (usually mounted on airplanes) have revealed the presence of rugged mountains within.
A 2017 map of Greenland stripped of ice shows a bowl-like depression in the center of the island. A ring of coastal mountains encircles this depression. The map reveals the underlying topography of Greenland's flowing glaciers, which can help scientists predict how fast glaciers will move under warming conditions and how quickly they will release icebergs into the ocean.
ancient lake
Hundreds of thousands or millions of years ago, before Greenland was covered in ice, this lake was home to another lake of considerable size.
Now, the lake has turned into a depression structure filled with sediment. Scientists note that the ancient lake was filled with water as deep as 250 m in several places. The lake basin covers 7,100 sq km and is fed by at least 18 different rivers.
The bottom of the lake can hold valuable clues about the past climate of the Arctic. But to discover this secret, it takes a 1.8 km deep ice sheet that now covers the ancient lake.
Hidden gem
The Greenland ice sheet also hides the view of a jewel-like lake filled with crystalline meltwater. There are at least 60 small lakes like this. Most of the lakes are clustered in northern and eastern Greenland. The findings were previously reported by Stephen Livingstone, senior lecturer in physical geography at the University of Sheffield in the UK and his team.
The size of the lake ranges from 200 m to 5.9 km. Melt water in these lakes may flow from the surface of the ice sheet, or it may melt due to friction from the movement of ice or geothermal energy from below.
Meteor impact proof
Not all of the topography under the ice sheet originates from Earth. Scientists have discovered at least two possible meteor craters buried under the ice. Both are in northwest Greenland. The first is under the Hiawatha Glacier, and the other is 183 km from the first.
Hiawatha Crater is under about 930 m of ice sheet, while the second crater is buried under a depth of 2 km of ice sheet. The second crater measures 36 km, making it the 22nd largest impact crater ever found on Earth. While the first crater is slightly smaller with a width of 31 km.
Perfectly preserved fossil plant
Ice cores excavated during the Cold War era to build nuclear weapons bases were rediscovered in 2017. These ice cores contain perfectly preserved plant fossils from a million years ago.
"The best way to describe it is by the freeze-dried method. When we took these fossils out and splashed them with a little water, they kind of stretched. So they looked like they were dead," said Andrew Christ, lead author of the ice core study and lecturer in the Department of Geology at the University. of Vermont in Burlington.
The ice cores originate in northwestern Greenland, and the plants that form them may have grown in boreal forests. Such forests can only grow in most frost-free conditions. This suggests that parts of the Greenland ice sheet may be younger than researchers previously believed.
