Inland waters are not only accumulations of liquid, but also solid moisture. Solid water forms mountain, cover and underground glaciation. The area of underground accumulation of ice was named the cryolithozone in 1955 by Shvetsov, a Soviet permafrost scientist. This area also has a more common name - permafrost.
Cryolithozone is the top layer of the crust. Rocks at this level are characterized by low temperatures. This layer includes permafrost, rocks, as well as non-freezing horizons of highly mineralized groundwater.
During a long severe winter with a relatively small thickness of the cover, there is a significant loss of heat from the rocks. As a result, freezing occurs to a considerable depth. As a result, solid masses of water are formed. In summer, permafrost does not have time to thaw completely. The soil retains a negative temperature, thus, at a considerable depth and for hundreds and even thousands of years. The permafrost of Russia is also formed under the additional influence of huge reserves of cold. They accumulate in areas with a lower average annual temperature.
For a long time at low temperatures, rocks are in some way “cemented” by moisture. Permafrost includes underground ice, accumulations of moisture form wedges, lenses, veins, ice layers. Permafrost can contain varying amounts of ice. The index of "ice content" can range from 1-3 to 90%. As a rule, ice occurs in mountainous areas. At the same time, permafrost in flat areas is characterized by increased ice content.
Cryolithozone is a unique phenomenon. Permafrost interested explorers in the 17th century. At the beginning of the 18th century, Tatishchev mentioned this phenomenon in his writings, and the first studies were carried out in the middle of the 19th century by Middendorf. The latter measured the temperature of the layer in several areas, established its thickness in the northern regions, and put forward an assumption about the origin and factors of the rather wide distribution of the permafrost zone. From the second half of the 19th to the beginning of the 20th century, serious research began to be carried out together with the exploration work of mining engineers and geologists.
In Russia, the permafrost zone is spread over an area of about eleven million square kilometers. This is about sixty-five percent of the entire territory of the state.
Permafrost from the south is limited to the Kola Peninsula. From its central part, it stretches across the East European Plain not far from the Arctic Circle. Then along the Urals there is a deviation to the south almost tosixty degrees north latitude. Along the Ob, permafrost stretches to the mouth of the Northern Sosva, after which it passes along the Siberian Uvals (southern slopes) to the Yenisei in the Podkamennaya Tunguska region. At this point, the border turns rather steeply to the south, runs along the Yenisei, then goes along the slopes of Altai, Tuva, Western Sayan to the border with Kazakhstan.
