"Dry Valleys" of Antarctica - the most unusual place on Earth

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:40

There is a place on Earth that is so unlike any other that it was used to test equipment that was supposed to go to Mars. The Dry Valleys region of Antarctica is one of the most extreme deserts in the world. And that's not her only feature.

Victoria Land in Antarctica, where they are located, was discovered in 1841 during the Ross expedition. She was named after the Queen of England.

Where are you

The dry valleys of icy Antarctica are a very unusual part of the mainland, formed by the location of the Transantarctic Ridge, which causes air to flow upwards over them. Because of this, they lose moisture, and snow and rain do not fall there. The mountains also prevent the ice from moving down the valleys from the East Antarctic Ice Sheet, and finally, strong katabatic winds (downward), blowing at speeds up to 320 km/h, also play a role. This is one of the most extreme climates on the planet, a cold desert where the average annual temperature ranges from -14°C to -30°C, depending on the location,while windy places are warmer.

They cover an area of about 4,800 square kilometers and, located at a distance of about 97 kilometers from McMurdo Station, have been the site for many years of research in connection with a number of related phenomena.

Discovery history

There are three great valleys here: the Taylor Valley, the Wright Valley and the Victoria Valley. The first was discovered during the Robert Scott Discovery expedition in 1901-1904. It was then explored in detail by Griffith Taylor during Scott's later Terra Nova Expedition in 1910-1913. In honor of him, she received this name. The valley is surrounded by high mountain peaks and no further exploration of the surrounding area was carried out at that time. It was only in the 1950s that new valleys and their dimensions were revealed on aerial photographs.

There is a lake in the Taylor Valley that may have become some sort of myth. It was officially named after Lake Chad in Africa, which means "large body of water" in the local language. According to legend, when a group from the Scott expedition of 1910-1913. located nearby, they took, as they believed, clean drinking water from it. But as a result, all members of the expedition suffered from terrible diarrhea, and, accordingly, a large amount of toilet paper was used. Her trade name was "Chad", hence the name of this lake. The disease was caused by toxic chemicals produced by cyanobacteria found in and around the water body.

Bloodywaterfall

It was first discovered by Griffith Taylor during Scott's Terra Nova Expedition in 1911. The reddish-brown color of the water, which gave rise to this name, is due to the presence of iron oxide, and not algae, as originally thought. This compound is found in a lake under the Taylor Glacier, where the unusual water chemistry allows chemoautotrophic bacteria to survive without any sunlight or organic molecules from outside.

They absorb large amounts of iron II (Fe2 +) and sulfate (SO4-) ions from the underlying rock and oxidize them to iron III (Fe3 +) ions, releasing energy in the process. The large and very s alty lake sometimes overflows, resulting in Blood Falls.

Mummified seals

This is another oddity of the Dry Valleys of Antarctica. Moreover, the mummies of these animals are many kilometers from the sea. Usually these are Weddell seals and crabeaters, found at a distance of up to 65 km from the sea and at an altitude of up to one and a half kilometers. Dating was carried out using carbon, as a result it turned out that their age ranges from several hundred to 2600 years.

They seem to have died relatively recently. Cold winds quickly dry out the carcass and lead to mummification. More "young" (about a hundred years old) are very well preserved. Sometimes they end up in lakes that may be subject to seasonal melting, which hastens their destruction. No one knows exactly how or why these seals ended up in the middle of the Dry Valleys. Antarctica.

Onyx River

Another surprise from this region. It is the longest river on this continent, although, in fact, it is just a seasonal flow of melt water.

It forms in the summer, coming from the lower Wright Glacier, and flows deep into the valley of the same name for 28 km until it reaches Lake Vanda. The flow is highly variable with temperature. In summer, it rises for several weeks, part of the glacial ice begins to melt and flows into the Dry Valleys of Antarctica. Onyx usually flows for 6-8 weeks, in some years it may not reach Lake Vanda, while in others it leads to flooding, causing significant erosion of the valley floor. This stream reaches a depth of up to 50 cm and can be several meters wide, it is one of the largest, consisting only of glacial meltwater.

Lake Don Juan

This is one of the most curious bodies of water on earth. It is the s altiest natural body of water on the planet. The salinity of the lake is more than 40% (1000 g of water in it contains 400 g of dissolved solids). This is higher than the s alt content in the Dead Sea by 34% and much more than in the oceans (average salinity 3.5%). In 1961, it was discovered by two helicopter pilots Don Roe and John Hickey, who were surprised by the fact that this lake did not freeze at a temperature of -30 ° C. It turned out - because of the amount of s alt in the water.

It was found to be formed from atmospheric water and a small amount of melted snow. S alts in surrounding soils near the surface absorb any waterpresent in the air or earth, which then dissolve into it. This concentrate flows into the lake. After that, part of the water evaporates, and the s alts are concentrated. 90% of it is calcium chloride (CaCl₂), not sodium chloride (NaCl) like in the world's oceans.

Maze

Dry valleys expose Antarctica's bedrock and have little to no erosion or vegetation. Therefore, their geological features are well preserved and, in most cases, clearly visible. One of the biggest and most striking such features here is the region known as "the labyrinth". It consists of a series of channels carved into a 300 m thick layer of rock, with a total length of about 50 km. They are 600 m wide and 250 m deep.

Its features indicate that for some time melt waters passed here in large quantities. The date of the last shower (there could have been several) is determined between 14.4 and 12.4 million years ago. It is believed that the channels of the labyrinth were most likely destroyed as a result of episodic drainage of the huge lakes that lie under the ice sheet of East Antarctica.

Lakes

Another counterintuitive find in the Dry Valleys is a series of over 20 permanent lakes and ponds. Some of them are extremely s alty. Some of them are quite small and freeze to the very bottom in winter. Lake Vanda is one of the largest: 5.6 km by 1.5 km, 68.8 m deep, it has a smooth permanent ice cover about 4 m thick, in summer, as the coastal ice melts.ice, a moat is formed. These lakes usually receive most of their water during the summer melt of nearby glaciers.

Because there is little or no snow in the Dry Valleys, the ice on the surface of the lakes is exposed and can be quite beautiful, very hard and transparent, blue in color, sometimes with small air bubbles. Lake water often contains a microbial ecosystem fed by sunlight.

A number of underground interconnected reservoirs have also been found there along with saturated s alt deposits.