Vast, City-Sized Lake Discovered Miles Below The Antarctic Ice Sheet !!

List members , this find is extremely valuable in itself , but it also proves that such sub-glacial lakes or oceans could exist on so many apparently frozen worlds (eg. Saturn's moon Titan , or the planetoid Pluto) :-

Vast, City-Sized Lake Discovered Miles Below The Antarctic Ice Sheet


10 MAY 2022

The Antarctic ice is finding its secrets harder and harder to keep.

Deep below the ice of the East Antarctic Ice Sheet, the largest ice sheet in the world, scientists have confirmed the existence of a huge lake of liquid water.

Researchers have named it Lake Snow Eagle, and believe that sediments within it could contain information about the evolution of the Antarctic ice sheet from its very earliest formation.

"This lake is likely to have a record of the entire history of the East Antarctic Ice Sheet, its initiation over 34 million years ago, as well as its growth and evolution across glacial cycles since then," says geophysicist Don Blankenship of The University of Texas at Austin's Institute for Geophysics.

"Our observations also suggest that the ice sheet changed significantly about 10,000 years ago, although we have no idea why."

Although East Antarctica is the coldest place on Earth, it's not completely frozen. Hundreds of lakes of liquid water – known as subglacial lakes – have been discovered hidden beneath the ice that covers the continent.

There are a number of factors at play that allow these reservoirs to exist. The mass of the ice sheet produces pressure, which dramatically lowers the freezing point of water trapped beneath it.

In addition, the ice sheet itself provides insulation against the frigid air, while rocks below provide a source of gentle heating. What's more, if the water is briny, saturated with salts, that too can lower the freezing point further.

We can detect subglacial lakes by using ice-penetrating radar from above. The radar signal is propagated through the ice and bounced back, and by comparing the transmitted signal with the returned signal, scientists can study what's below the ice.

A radar signal that bounces back through liquid water is brighter, or more reflective, than other media.

In the case of Lake Snow Eagle, the first hint was a large depression observed in the ice sheet, revealed by satellite images.

So a research team, led by geophysicist Shuai Yan of The University of Texas at Austin, set about obtaining radar data for the region, as well as measurements of Earth's magnetic field, over a period of three years, from 2016 to 2019.

Analysis of the radar data revealed a large patch, deep below the ice, shining brightly. This, the researchers confirmed, was Lake Snow Eagle: one of the largest subglacial lakes ever discovered.

"I literally jumped when I first saw that bright radar reflection," Yan says.

The body of water lies some 3.2 kilometers (2 miles) below the ice sheet, and it's substantial. It measures some 42 kilometers in length and 15 kilometers in width, covering an area of 370 square kilometers, and containing 21 cubic kilometers of water, with a depth of 200 meters (656 feet).

Lake Snow Eagle sits in a jagged canyon 1.6 kilometers deep, buried beneath the ice, but the radar reflections reveal that there's more than just water in the hidden lake.

At the bottom of the lake sits a layer of unconsolidated sediment. Given how long it takes sediment to accumulate in these subglacial environments, the team believes it must have been there for a very long time – perhaps since before the ice sheet even formed.

"This lake's been accumulating sediment over a very long time, potentially taking us through the period when Antarctica had no ice at all, to when it went into deep freeze," says glaciologist Martin Siegert of Imperial College London in the UK.

"We don't have a single record of all those events in one place, but the sediments at the bottom of this lake could be ideal."

Given that it's trapped under several kilometers of ice in one of the most hostile environments on Earth, actually getting to the lake to investigate it further is likely to prove the next challenge.

The team proposes that a station be installed close by, to facilitate future efforts to study the mysterious lake and sample its ancient sediment.

The research has been published in Geology .


Folks , now just contrast this with Saturn's largest moon Titan , that is similarly frozen on it's outer surface :-

Saturn Moon Titan's Underground Ocean May Be Super Salty

By Kelly Dickerson published July 05, 2014

Saturn Moon Titan's Ocean Super Salty

Titan's ice shell, which overlies a very salty ocean, varies in thickness around the moon, suggesting the crust is in the process of becoming rigid, researchers say. (Image credit: NASA/JPL -Caltech/SSI/Univ. of Arizona/G. Mitri/University of Nantes)

The subsurface ocean inside Saturn’s largest moon, Titan, could be as salty as any body of water here on Earth, a new study reports.

Gravity data collected by NASA’s Cassini spacecraft suggest that Titan’s ocean must have an extremely high density. Salt water has a higher density than fresh water because the presence of salt adds more mass to a given amount of water.

Researchers think the ocean could be as salty as the Dead Sea of Israel and Jordan, with a high concentration of dissolved salts made of sulfur, sodium and potassium. [Amazing Photos: Titan, Saturn’s Largest Moon]

"This is an extremely salty ocean by Earth standards," study lead author Giuseppe Mitri, from the University of Nantes in France, said in a statement. "Knowing this may change the way we view this ocean as a possible abode for present-day life, but conditions might have been very different there in the past."

The average salt concentration in Earth’s oceans is around 3.5 percent, but parts of the Dead Sea can reach 40 percent salinity.

Titan is surrounded by an ice shell, but below the surface, scientists believe there is an ocean of liquid water that could be just as salty as the Dead Sea.

Cassini collected gravity and topography data during its flybys of Titan over the past 10 years, allowing researchers to create a new model of the structure of the moon’s outer icy shell.

The new model suggests that the thickness of the icy crust varies across the moon’s surface. This means that the ocean underneath is probably in the process of freezing, too. If the ocean is freezing, it would decrease the chances that the ocean could support life, since freezing would limit the exchange of materials between the water and the surface, researchers said.

The new data could also provide some insight into Titan’s unique atmosphere, which is consistently around 5 percent methane. It is still a mystery how Titan maintains methane in its atmosphere since sunlight quickly breaks up the gas.

Scientists believe some kind of natural process must be cycling the methane into the atmosphere; from there, it falls back down to the surface as methane rain, similar to the water cycle on Earth. Since Titan’s surface is mostly frozen, researchers think any methane rising into the atmosphere must be coming from a few scattered unfrozen "hot spots."

The $3.2 billion Cassini mission launched in 1997 and arrived in orbit around Saturn in 2004. The mission also dropped a probe named Huygens onto the surface of Titan in January 2005.

The new study was published July 1 in the journal Icarus.