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Topic Last Updated on 02-07-2024
Secrets of the Peaceful Continent
Antarctica was lucky: in 1959 in Washington, the 12 countries that had scientific missions on the continent signed an agreement to ban establishing military bases, conducting military maneuvers, and testing any kind of weapons on its territory. Since then, humans have gone there exclusively in the name of science. The results of the work of one such mission suggested that at a depth of several miles under the ice cap of Antarctica, the temperature is close to the melting point of ice. This assumption was expressed in 1957 and was the first step to a grand discovery.
Andrey Kapitsa
Another mission involved seismic soundings of ice in the area of the Soviet-operated Vostok Station (the word vostok means “east” in Russian), which was conducted by a scientific expedition led by Soviet geographer Andrey Kapitsa, son of Nobel laureate Pyotr Kapitsa. As a result, a signal was recorded, reflecting off a surface under the ice. For about 30 years, it served as evidence of the presence of a layer of frozen rock under an ice shell many miles deep. However, the reflecting plane was so smooth that even Andrey Kapitsa suggested that there must be a huge subglacial lake with a length of more than 155 mi, a width of over 30 mi, and a depth of more than half a mile!
It wasn’t until the 1990s that a technique was developed to confirm the existence of a body of water. The powerful radar and modern radio-locating method of geomagnetic deep sounding (GDS) enabled a British-Russian collective of scientists, led by Gordon Robin, to get results that even the most consummate of skeptics could not doubt: there is a giant lake under the layers of ice. Its contours appear on the icy surface of the continent. Jeff Ridley proved this in 1993 through the use of extremely precise satellite laser altimetry. It turns out that the Vostok Polar Station is in the center of an icy plain that is as flat as a table and can be considered a projection of the lake onto the surface.
The Vostok Station
The climatic conditions at the Russian Vostok station are probably the most severe on the planet. In July 1983, the lowest temperature on Earth was recorded there: –128.6°F (in such cold, eyeballs freeze almost instantaneously). The altitude of the station, 11,443 ft above sea level, causes a constant shortage of oxygen among polar explorers.
Living conditions at Vostok demand extensive adaptation, resulting in weight loss of up to 22–26 lbs. Since 1957, researchers have studied Antarctica’s climate, geology, and drilled into its ice. The nearby South Magnetic Pole is also a subject of study. Life around Vostok is scarce, with only trace amounts of microorganisms. The station hosts up to 50 people in summer but drops to 20 during winter.
Borehole 5G | Lake Vostok
The water in the lake has been completely isolated from the outside world for several million years. However, evolution continued there, and biological species appeared and went extinct. Life underwater “froze,” which, of course, means it is of great interest to researchers.
In 1990, the first thermal drills dug into the ice of Antarctica in the area of the Vostok station. The goal was to get to the lake and take samples of its unique water. It should be noted that Soviet scientific expeditions had been drilling into the ice of the southern continent since the 1970s — four of their wells were classified as being deep.
5G Well
Therefore, when the thermal borehole at Lake Vostok was drilled, the well was called “5G”, from the Russian piataia glubokaia, or “fifth deep well.” This was achieved through thermal boring, when ice is melted by the movement of a heated drill head. This required a huge amount of electricity — ten times more than with traditional mechanical drilling. For this reason, and also because of the poor quality of the ice patch selected, the researchers switched out the thermal drill for the electromechanical KEMS–132. This shift happened at a depth of 9,000 ft.
Why work stopped?
But in 1998, at the 11,886-ft mark, the work was stopped. Why? Drillers were using a mixture of aviation kerosene with a special weighting agent, freon, as drilling fluid. The weighting agent is necessary to fully compensate for the rock pressure of the ice mass: without it, the borehole may collapse into itself. Can you imagine what this poisonous mixture would do if it got into the lake? The majority of its unique biota would die as soon as the drill entered the water.
That is why, for the purpose of preserving the lake’s ecology, work was suspended for eight whole years, just a little under 500 ft away from the lake’s surface. This was on the initiative of SCAR, the Scientific Committee on Antarctic Research. Later, oligodimethylsiloxane silicone fluid compounds came along to help researchers and drillers. This hydrophobic liquid, due to its chemical inertness, is harmless to humans and animals, which means there is a good probability that its effect on the microorganisms of the lake is also neutral. Additionally, the mechanical drill was replaced with a thermal one.
Ice Cuttings from Different Borehole Depths
The ice shell on the surface is constantly forming as snow is compacted by new precipitation and becomes immersed in lower layers, where it has a granular structure and is located at a depth of up to 177 ft. Further on, it becomes denser — in the more recent snow, up to 6,027 ft, bands of annual snowfall are clearly visible. At the bottom of the borehole (10,009 ft), the ice has impurities of sand and silt. The lower the layer of ice, the more pressure it is under.
The TBPO-132 creates an additional buffer layer in thawing water under an organosilicon wash solution. The density of the liquid in the well had to be lowered, the pressure was 0.3–0.4 MPa, below the estimated pressure in Vostok. This way, the drilling mud would not enter the lake. The water had to independently travel 100–130 ft upwards in the borehole and instantly freeze. It was proposed that the “fresh” relict ice be obtained with the help of a mounted electromechanical drill.
The Uncovering
On November 28, 2011, a new drilling unit arrived at the Vostok Station to undertake its journey downwards. By January 12, 2012, the ice-borer reached a depth of 12,262 ft, and on February 4, at a depth of 12,355 ft, it came into contact with the surface of the water, thus ending the under-ice lake’s 15 million years of isolation.
