Is farming possible in permafrost zones? Method of thermal reclamation of land in the permafrost zone.

permafrost Krasnoyarsk region

The main reason for the occurrence permafrost- an exceptionally cold climate in which rocks have temperatures below their freezing point. Permafrost is the result of harsh climatic conditions, mainly harsh winters with little snow.

The following factors contribute to the formation and preservation of permafrost:

negative average annual temperatures, severe and long winters, the depth of freezing exceeds the depth of summer thawing.

Permafrost has a certain effect on economic activity person. In Russia, the development of permafrost began in the thirties of the 20th century. Russian permafrost scientists have developed special systems technical measures that prevent negative consequences permafrost. These technical innovations make it possible to develop permafrost areas.

Permafrost has great influence on human economic activity. It creates significant obstacles to excavation work, construction and operation of various buildings, etc. Heated buildings erected on permafrost settle over time due to the thawing of the soil underneath them, cracks appear in them, and sometimes they collapse. Permafrost also complicates water supply in populated areas and on railways. This required development special methods construction in permafrost conditions.

Permafrost contributes to swamping of agricultural lands, as a result of which additional reclamation work is necessary, i.e., removing excess moisture from the fields.

The benefit of permafrost for humans is that they use it as unique fridge. It preserves food for a long time: fish, meat, berries, fruits, seeds.

Permafrost is a good fastening material in mines and mines. It has now been established that in permafrost areas there are many minerals: coal, gas, diamonds, gold, nickel, copper, tin, salts. There is a lot of fresh water in these areas.

Unfortunately, permafrost accidents are currently occurring. The reason is climate warming, man-made “warming”. The consequence is uneven settlement of buildings, destruction of foundations, and their deformation.

In the Norilsk industrial region, over the past 10 years, due to the deterioration of the permafrost, 250 buildings have been damaged, 100 objects are in disrepair, about 40 multi-storey residential buildings built in the 60-80s have been demolished or are subject to demolition.

Almost 60% of buildings and structures are deformed. In the cities of Igarka, Dikson, Vilyuysk, 60% of buildings are deformed. 100% of buildings and structures in national villages Taimyr District up to 100% of buildings are damaged. In Vorkuta, about 40% of buildings were damaged. In Yakutsk, since the 70s of the 20th century, 300 buildings have been damaged due to subsidence. If the man-made “thaw” continues, people will have to rebuild many residential buildings and industrial enterprises, re-lay roads and railways.

Permafrost has a diverse impact on the nature of the provinces where it is widespread. First of all, it makes it difficult to move groundwater-- sub-permafrost, inter-permafrost and, especially, supra-permafrost, located closest to the day surface. This greatly limits the underground feeding of the Srednyaya and Eastern Siberia. Under these conditions, groundwater often forms ice dams, swelling mounds and other forms of relief, giving specific features to the land surface of the eastern regions of Siberia. In the northeast of the CIS there are about 4,000 aufeis (taryn in Yakut), which contain about 25 billion m3 of ice. Thawing of frozen soils and their subsidence contribute to the wide distribution of thermokarst and the resulting unique topography of the North Siberian, Indigirka, Kolyma, Central Yakut and other lowlands and plateaus in permafrost areas.

Permafrost negatively affects the development of vegetation and soil cover. Plants in conditions of excess cold do not receive normal nutrition and produce insignificant growth organic matter, do not sufficiently cover the soil surface. Permafrost has a particularly detrimental effect on woody vegetation, which has a clearly depressed appearance, a sparse stand of trees, poor species composition. In Central and Eastern Siberia, the Daurian larch is the tree that best withstands permafrost.

In the provinces where permafrost is widespread, the soil cover. In Central and Eastern Siberia, coarse-skeletal rocky soils are widespread due to the predominance of frost weathering over chemical and biological weathering; on the plains there are swamping phenomena everywhere. Soils under these conditions are primitively developed, thin, characterized by sharply suppressed biochemical processes and a lack of nutrients.

Solifluction phenomena are widespread in Central and Eastern Siberia, which, along with thermokarst, are of great relief-forming importance.

Permafrost affects the relief, as water and ice have different densities, as a result of which freezing and thawing rocks undergo deformation. It is also important that frozen soil does not allow water to pass through.

The most common type of deformation of frozen soils is heaving, associated with an increase in the volume of water during freezing. The resulting positive forms relief are called heaving mounds; their height is usually no more than 2 m. If heaving mounds formed within the peaty tundra, then they are usually called peat mounds; peat is a good heat insulator; the permafrost beneath it persists for a long time and often in those places that are considered free from permafrost, for example on Kola Peninsula. The height of peat mounds can reach 3-7 m; they are usually round in plan, sometimes located singly, but more often in groups.

In summer top layer permafrost is thawing. The underlying permafrost prevents meltwater from seeping down; the water, if it does not flow into a river or lake, remains in place until autumn, when it freezes again. In the spring, thawing proceeded from top to bottom, as a result of equalizing the temperatures of already warmed air and still cold soil; In autumn, temperature changes also occur faster in the air and freezing also occurs from top to bottom. As a result, melt water ends up between a waterproof layer of permanent permafrost from below and a layer of new, seasonal permafrost that gradually grows from top to bottom. Ice takes up more volume than water. Water, caught between two layers of ice under enormous pressure, finds the most weak point in the seasonal frozen layer and breaks through it. If it pours onto the surface, an ice field is formed - frost; The geomorphological significance of the aufeis lies in the fact that intense frost weathering occurs along its edges. If there is a dense moss-grass cover or a layer of peat on the surface, the water may not break through it, but only lift it, spreading under it. Having then frozen, it forms the ice core of the mound; Gradually growing, such a mound can reach a height of 70 m with a diameter of up to 200 m.

Climate warming, disruption temperature regime soils due to deforestation, construction, etc. can lead to the thawing of individual areas of permafrost, which will cause soil subsidence, the formation of sinkholes, underground cavities and other negative forms of relief that outwardly resemble karst. The processes of relief formation caused by local thawing of permafrost, and all the forms created by them, are called thermal karst, or (more often) thermokarst (Greek therme - heat). In areas where thermokarst is distributed, there are many rounded depressions; lakes are usually located in them, since the moisture is excessive, and the underlying permafrost is waterproof. Thermokarst lakes differ from karst lakes in more correct form and less depth. In the flat parts of central Yakutia, alas are often found - flat-bottomed thermokarst basins from tens of meters to several kilometers in diameter and up to 15-30 m deep. Alas are often occupied by lakes, swamps, meadows; sometimes they represent depressions of drained or overgrown thermokarst lakes.

In permafrost conditions, especially if the ice content in the frozen rock is high, water produces not only a mechanical, but also a temperature effect on the rock, since melting ice contributes to the destruction of the rock. Therefore, special terms have been introduced - thermal erosion and thermal abrasion. Thermal erosion manifests itself in the fact that rivers easily erode their banks, and the ravine network reaches incredible density even in very flat terrain (for example, in Yamal); thermal abrasion sometimes causes rapid retreat of shores under the influence of sea waves.

Landforms associated with permafrost can also be located where there is no permafrost now, that is, they can be of a relict nature. So, in the middle and southern parts The Komi Republic currently does not have permafrost, but shallow round lakes are often found; on aerial photographs the grid of polygonal soils is clearly visible, especially clearly visible on high river terraces.

Total area greenhouses in 2016 was 0.75 hectares. The production of greenhouse vegetable products amounted to 76.6 tons. Revenue from the sale of greenhouse vegetables amounted to almost 26.1 million rubles. (2015 - about 24.9 million rubles) with a planned value of 24.8 million rubles. Thus, the implementation of the planned indicator was 105.1%. Average number In 2016, the number of workers employed in greenhouse crop production on the district's farms was 25 people. 27.6 million rubles were allocated for the implementation of the subprogram “Crop Production Development”, while funds from the district budget amounted to about 26.3 million rubles, and enterprises’ own funds amounted to over 1.3 million rubles.

Oleg CHESNOKOV
[email protected]

Less than a month left before the start of the next northern delivery. On the first ship, among other cargo, fresh fruits and vegetables will be delivered, almost all of them are imported; domestic vegetables for storage will arrive in Chukotka only in late summer and autumn. Vegetables grown in the district will so far make up only a small percentage of the total.

BOTH YOURSELF AND PEOPLE
But in Soviet times subsidiary farms existed on every collective farm, state farm, and every reindeer herding farm in the district, for which appropriate funding was provided. There was also a clear market. And most importantly, then the cost of a helicopter flight hour was affordable for any agricultural enterprise. Vegetables that are sufficient quantity were grown by private farms, and were delivered, among other things, to reindeer herding brigades, to transshipment depots, to remote villages of the Arctic coast, not to mention regional centers.
Today, according to the head of the district Department of Agriculture, Sergei Davidyuk, two agricultural enterprises in the district (Markovsky and Vaezhsky) have 10 hectares of arable land. Of these, only 2 hectares are actually used for their intended purpose. Plus private owners have several hectares. From these areas in 2016, approximately 24.5 tons of potatoes were harvested (2015 - 18.8 tons) and 4 tons of other open-ground vegetables. Vegetable products grown by the population are mainly used to satisfy personal needs and partly to supply social institutions.

IN SUPPORT OF PLANT PRODUCTION
The main reasons hindering the use of the remaining land are the cost of transportation and storage problems. Farms can grow more, but storing and exporting the crop is a problem for them. In addition, in most places, livestock farming, which is directly related to crop production, is a thing of the past: there is no main organic fertilizer - manure, which means there is no previous productivity. It has gotten to the point that private owners bring it to Markovo along the winter road from Vaeg, where there are still cattle. Silting after river floods helps a little, since the layer of silt is also good for crop production. But, giving organic matter, it at the same time acidifies fertile land, which without the application of manure and other fertilizers sharply reduces yields. Farms do not import fertilizers from the “mainland”.
“As a result, in 2016 the potato yield amounted to 80-90 centners per hectare,” states Sergei Nikolaevich. - This is, to put it mildly, not the most high rate: we can grow 200-250 quintals.
The district government drew attention to this state of affairs and today the region has a subprogram “Development of crop production”, which, in addition to supporting enterprises engaged in indoor crop production, subsidizes trading organizations that buy crops from private traders specializing in vegetable growing for further sale and processing. Thus, the Anadyr Trading Company is allocated subsidies to compensate for transportation costs for transporting vegetables to the consumer. This makes it possible to deliver vegetable products from the place of cultivation to other populated areas. Last year, the company purchased about 20 tons of potatoes from private owners and sold them to consumers in other villages (KS talked about this in No. 11 of March 24, 2017).
- We support everyone, but different conditions, - adds the head of the district Department of Agriculture. - For example, if this is a farmer, then his farm should be registered not in the urban district, but in rural areas- in a village or in an inter-settlement area, since only they can receive federal support on co-financing terms.

WATER IS THE SAVIOR
According to our interlocutor, areas suitable for agriculture in Chukotka are mainly located in river deltas: where there is water, the permafrost disappears.
“Water is a heat-intensive substance; it warms the earth over the summer and displaces permafrost into the depths,” explains Sergei Davidyuk. “During the winter, it manages to rise a little again, but about three to five meters of unfrozen soil remains on top, which is enough for plants to live. In other places, most of the humus layer, when frozen, as in a fire, loses its properties - it dies. Therefore, farming there is only possible in closed ground, that is, in greenhouses. Our district is located in a zone of not just risky farming, but unpredictable risk. According to statistics, even in Markovo for a quarter of a century, during 80% of this time there were practically no crops in the open ground; vegetables grew only in greenhouses.
The development of crop production can give an additional impetus to the revival of livestock farming in the region. These directions are always in direct connection with each other. Previously, all collective farms, state farms, and reindeer herding farms had their own chickens, pigs, and cows. A three-year supply of feed was kept for them. In case of ice, it was even taken out to the herds to feed the reindeer. Today this is only possible with the organization of feed production in the region. The revival of private farms will ensure demand for these feeds. Conversely, the availability of feed will support livestock production. The contract system, when people took animals for fattening, can also be revived. Then it will be possible to reduce the volume of meat imported from the “mainland” to the limit.
“Once upon a time we had specialists from the Magadan Research Institute working with us who studied the possibilities of crop production on drained thermokarst lakes,” the specialist recalls. - The main goal was to grow feed for dairy farming, which was practiced in the district. Then it turned out that for 600 heads of livestock, with sufficient investment, it was quite possible to grow feed using this technology for 5-7 years, until the return of permafrost. Then the water was collected again, it replaced the permafrost in five years, and the process was repeated.

STORAGE TO HELP
A real boom in the greenhouse business has begun today in Chukotka. New enterprises for growing greens and vegetables in greenhouses are planned to open in the regional capital, Pevek, Anadyrsky district and in the Providensky urban district. But for now, the largest producer of vegetable products on a systematic basis remains the Rosinka vegetable factory, which grew 76.6 tons last year (72.4 tons in 2015).
Today, per one resident of the district, according to statistics, we produce 1.6 kg of greenhouse vegetable products. This is only 10% of the recommended norms. That is, the district imports 90% of its vegetable products. But half of this amount, according to Sergei Davidyuk, can be grown by yourself.
Various technologies make it possible to grow vegetables in greenhouses all year round. In addition, these are guaranteed jobs.
But there is another important factor hindering the development of crop production in the region, associated with the lack of local modern bases storage of vegetables. This creates a lot of problems, primarily for socially significant consumers - hospitals, schools, kindergartens, who require a certain amount of vegetables at once. And it’s easier for trade organizations to export vegetable products to required quantities on winter roads.
The appearance of storage facilities will give an additional impetus to crop production and reduce dependence on supplies from the “mainland.” In essence, this will be the revival of the procurement offices that once existed. Therefore, the issue of building vegetable storage facilities in Markovo, Vaega and some others is currently under discussion in the district government. populated areas, located in vegetable growing areas, where they will be stored until the winter roads open, and then delivered to consumers in the region.

Usage: in agriculture, in particular for agricultural development of lands in the permafrost zone. The essence of the invention: the method includes thawing permafrost soils on an area with a slope of at least 0.04 - 0.06, and repeated harrowing across the slope, for example with disk harrows, until it is mixed with the underlying mineral soil and a layer with a uniform lumpy structure is formed. 4 ill.

The invention relates to land reclamation for agricultural development of territories in the permafrost zone. There is a known method of developing tundra lands by draining thermokarst lakes and using their bottoms as meadows. The disadvantage of this method is the degradation of meadow basins and their loss from economic use after 5-7 years, due to cooling of the bottom of the basins, the ecological situation over large areas, thermal erosion occurs, swamping of the tundra, and a reduction in the area of ​​reindeer pastures due to the destruction of moss and reindeer moss. There are known methods for developing land in the permafrost zone, which are based on the principle of land drainage with various technical and technological methods: with closing drainage channels for the summer period, with the introduction of mineral soil onto the surface of the drained area, with surface leveling techniques to accelerate the drainage of groundwater, with thawing of frozen soil to a minimum required value. The disadvantage of these methods is the impossibility of using them when developing gentle tundra slopes. The closest to the proposed method is the method of thermal land reclamation in the zone permafrost for the development of tundra slope areas for the purpose of agricultural use of land on rough terrain, which consists in the fact that a layer of drainage material is poured across the slope, and up the slope next to it a platform is made, buried below the daytime surface by the amount of the vegetation layer. The first disadvantage this method The coefficient of use of the territory is low, since the area of ​​the artificial terrace on the slope, filled with drainage material and soil layer, is approximately equal to the area of ​​the artificial excavation, and the coefficient of development of the slope territory is approximately 0.5. The second disadvantage is the impossibility of using agricultural machinery and equipment for sowing and harvesting crops due to the destruction of the artificial excavation with water and the terrace with bulk soil. The third disadvantage is the labor intensity and large capital costs of constructing terraces, built at the base from imported drainage material, and on top from soil taken from an excavation on the slope. The most significant disadvantage of this method is the fragility of the artificial excavation in permafrost soils, which is filled with water from melting snow or precipitation. Removal of tundra soil cover is artificial thermokarst, leading to thermal erosion, gully formation and slope destruction (maximum two years). Claimed technical solution is aimed at increasing the efficiency and durability of agricultural land use in the permafrost zone and maintaining environmental balance. The task is achieved by the fact that according to the method of thermal reclamation of land in the permafrost zone in the spring, after the soil has thawed by 20-30 cm, the surface covered with a moss-humock layer and having a slope of at least 0.04-0.06 is repeatedly harrowed across the slope, for example , disc harrows until mixed with the underlying mineral soil and the formation of a layer with a uniform lumpy structure. They begin work on thermal reclamation of the tundra surface of the slope after achieving the required minimum thawing of frozen soil of 20-30 cm to ensure normal work disc harrows. To ensure effective underground flow formed in the seasonally thawed layer from the thawing of permafrost as a result of thermal reclamation, the minimum slope of the slope surface must be more than 0.04-0.06, the maximum is limited only by the technical capabilities of agricultural machinery. At lower slopes (less than 0.04-0.06), as practice shows, moisture accumulates on the surface, forming thermokarst subsidence and soil failures. The surface of the reclaimed slope area must be treated repeatedly, in approximately 6-8 tracks, with disc harrows in order to achieve good grinding of tussocks, moss and mixing of this organic mass with the underlying mineral soil until a layer of depth 25-30 cm with a uniform lumpy structure is formed. This surface treatment allows you to completely destroy the powerful thermal insulation “cushion” of moss and tussock, which greatly limits the flow of heat. solar energy into the ground. Secondly, such a moss-humock “cushion” reliably isolates the seeds of wild-growing (hay) grasses from contact with the mineral layer, which is located under it at a depth of 20-25 cm. After harrowing and destruction of the heat-insulating “cushion”, a change occurs thermal regime soil, which is expressed in a sharp increase in heat flow into the soil. The increased accumulation of heat by the soil is caused by a change in the thermophysical characteristics in the new crushed soil layer of mineral and organic components: an increase in the coefficients of thermal conductivity, thermal diffusivity and heat capacity. As a result, by the end of the thermal period of the first year of aging, there is a maximum increase in the power of seasonal thawing of the soil by 50-70% (for the conditions of the Anadyr region of Chukotka) compared to the untreated territory (control). After completion of spring land reclamation work, you can move on to the stage of agricultural development, for example, sowing perennial hay grasses. By the end of the warm period of the second year after the start of reclamation work, there is already a slight increase in the capacity of soil thawing, by only 20-25% compared to the untreated area (control) or by 10-15% compared to the treated field of the first year of development. By the end of the 3-4th year of aging, the relative increase in the power of seasonal thawing of soils from thermal reclamation according to the proposed method is almost complete, amounting to 5-15% with the control. From this moment, a new stabilized state of heat exchange between the upper active layer and environment, which is fixed by the diagram in Fig.4, compared with the initial (undisturbed) steady state of heat exchange in Fig.1. Thus, the proposed method of land reclamation is based on the use of only such technogenic influences that cause a slight change in the dynamics of heat exchange in the active layer. In this case, the value heat flow into the ground will not exceed a certain critical level, above which intensive (catastrophic) thawing of frozen soils and the development of thermokarst processes can occur: thermal subsidence, thermal erosion, ground failures with exposure of vein ice, gully formation. When implementing the proposed method of land reclamation, it is unacceptable to use such technogenic impacts that are associated with horizontal displacement soil: for example, loosening and turning over layers of soil (turf) with a plow or loosening and moving soil when leveling the surface. Such treatment methods are unacceptable and can cause irreversible permafrost degradation. Figure 1 shows a section along the slope before work began; Fig. 2 shows the same section after cutting and grinding the moss-humock “cushion” with mineral soil; Figure 3 shows a section of the slope after the first or second year of aging; Figure 4 shows a section of the slope at the moment of reaching a new steady state of heat exchange between the upper active layer and the environment. The drawing shows: 1 the surface of the territory before performing thermal reclamation work, 2 upper limit permafrost soils, 3 re-wetted ice (IWL), 4 permafrost soils (soils of IWL cores), 5 the surface of the territory after reclamation work, 6 the surface of the territory after sowing crops in the 1st-2nd year of development, 7 the upper limit of permafrost soils in the process of ice melting, 8, 9 the new upper boundary of permafrost and the position of the ice zone after the end of ground ice melting and stabilization of this process (by the end of the 3-4th year). The proposed method of thermal land reclamation was experimentally tested for four years on experimental production fields with an area of ​​38 hectares of the suburban livestock farm "Severny" near the city of Anadyr on tundra gentle slopes during the development of land for hay meadows, open ground vegetable growing, and pastures. The method has shown high efficiency in growing perennial grasses for green fodder, hay and growing radishes. The method has prospects for use in all regions of Chukotka and other subarctic and arctic regions of the North, opens great opportunities agricultural development of vast tundra territories with continuous distribution of permafrost rocks containing recurrent ice wedges and never previously used.

Formula of invention

METHOD OF THERMAL RECLAMATION OF LAND IN THE PERMAFROST ZONE, including thawing of permafrost soils on rough terrain, characterized in that in the spring after the soil has thawed, the surface is covered with a moss-humock layer on 20 - 30 cm and has a slope of at least 0.04 - 0.06 repeatedly harrowed across the slope, in particular with disc harrows, to mix with the underlying mineral soil and form a layer with a uniform lumpy structure.

Permafrost occupies 65% of Russia's territory. By geographical location it is divided into subaerial, subglacial and shelf.

Subaerial cryolithozone- maximum in area - represented from the surface by permafrost rocks. In the European part of the country, it is distributed only in the tundra and forest-tundra; from its southern border goes to the mouth of the Mezen River and then almost along the Northern Arctic Circle to the Urals. IN Western Siberia the boundary of the permafrost zone has a latitudinal extension to the Yenisei River; near the river Podkamennaya Tunguska it turns sharply to the south and runs along the right bank of the Yenisei. To the east of the Yenisei, permafrost is distributed over most of the territory, with the exception of the south of Kamchatka, the island, Primorye and some other areas. The thickness of frozen strata varies from 100–200 to 1500 m (Central Siberia).

Subglacial cryolithozone known under glaciers, where it is characterized by abnormally low thicknesses for high latitudes and high temperatures, as well as under glaciers in the mountains in North-East Russia and Altai.

Shelf cryolithozone widespread in arctic seas off the coast of Siberia. The oceanic permafrost zone occupies a significant part of the Arctic basin, with the exception of areas influenced by the warm North Atlantic Current.

Seasonal freezing of rocks covers most of the rest of Russia, except for the subtropical zone, where it does not appear annually and its depth does not exceed several centimeters. The depth of seasonal freezing decreases zonally with increasing rock temperature and increases with increasing continental climate from west to east. Largest values(up to 4–8 m) seasonal freezing reaches in areas with a sharply continental cold climate, little snow, severe winters (Central and Southern), in coarse soils with low humidity. The thickness of the seasonal freezing layer determines the depth of communications and building foundations.

Continuous permafrost is widespread in the northern part of the Bolshezemelskaya tundra, in the Polar Urals, in the tundra of Western Siberia, in the northern part of the Central Siberian Plateau, on the Taimyr Peninsula, the archipelago Severnaya Zemlya, on the Yana-Indigirskaya and , in the delta of the Lena River, on the Central Yakut Plain, the Lena Plateau and in the areas of the Verkhoyansk and Chersky ridges, the Kolyma Highlands, the Anadyr Plateau, as well as on the Yukagir Plateau and the Anadyr Lowland. The thickness of permafrost strata varies from 300 to 500 m or more, in the mountains - up to 1500 m; temperatures - from –2°C to –10°C and below. In the zone of continuous permafrost, thawed rocks occur only in channels big rivers and under large lakes. To the south of this zone, frozen rocks alternate with thawed rocks.

Permafrost with islands of thawed soils (intermittent, sporadic) prevails in the Bolshezemelskaya and Malozemelskaya tundras, between the Nizhnyaya and Podkamennaya Tunguska rivers, in the southern part of the Prilensky plateau, in Transbaikalia. The thickness of frozen strata sometimes reaches 250–300 m, but more often varies from 10–20 to 100–150 m, temperature - from 0°C to –2°C. The main reasons for the formation of taliks in the zone of discontinuous permafrost are the surface and radiation regime of the Earth's surface.

Island permafrost is developed on the Kola Peninsula, in the Kanino-Pechora region, in the taiga zone of Western Siberia, in the southern part of the Central Siberian Plateau, in the Far East, along the coast and on the peninsula. The thickness of the strata varies from several meters to several tens, temperatures are close to 0°C. Island permafrost is also typical for mountainous countries- Sayan, Urals and Caucasus, where it is found mainly on the periphery of the regions modern glaciation. In the zone of island permafrost, massifs of modern frozen rocks are preserved in icy peat and loamy rocks, in forests with a large shading effect, on slopes of northern and eastern exposures.

Ice in frozen rocks is represented by two types: 1) crystals, layers, veins (cryogenic textures) and 2) monomineral ice rock (polygonal veins and sheet ice, cores of heaving mounds). In crystalline and metamorphic rocks, ice occurs in the form of veins that fill cracks, in sands - in the form of lenses and small crystals, in clays, loams, sandy loams and peat - in the form of layers or a network. A special place occupy lattices of ice veins that penetrate the rock to a depth of 20–50 m. They are widespread within the West Siberian and Central Yakut plains, the North Siberian plain and on loose unlithified rocks. Freezing of the upper rocks often leads to the formation of seasonal and perennial hydrolaccolith mounds containing an ice core; they are found most often in Transbaikalia, Taimyr, in the north of Western Siberia, where they are called Bulgunnyakhs. In mountainous regions, in river valleys and on slopes, aufeis are common - covers of ice formed when groundwater freezes, poured out under the pressure that occurs during seasonal freezing, as well as when outlets freeze artesian waters. Thawing of ice formations contained in rock strata usually leads to subsidence, the appearance of craters, rounded depressions, etc., landforms (thermokarst), surface landslides, ground flows (solifluction).

The ice content of frozen rocks varies, there are three main varieties: low-ice, mainly sands and bedrock (ice less than 20%), medium-ice loams and sandy loams (ice 20–40%), and highly icy lake-marsh and alluvial deposits, represented by peat and loam (ice more than 40%).

Permafrost processes

Within the permafrost zone, five types of territories can be distinguished, differing in their set of predominant cryogenic processes. Within the plains of the North of the European part of Russia and Western Siberia, thermokarst and heaving are observed. To the east, in more severe climatic conditions, frost cracking additionally forms on the tundra and forest-tundra plains. For larger territory The low and middle mountains of Siberia are characterized by thermokarst, heaving, aufeis, solifluction, and kurums. IN high mountains, depressions, low plains and river valleys of the taiga zone of Central and Eastern Siberia, Far East aufeis, solifluction, and kurums predominate. For the middle and low mountains in the south of the permafrost zone of Russia, where discontinuous and island permafrost is widespread, thermokarst and solifluction processes are typical.

With the continuous distribution of permafrost, a layer of seasonal thawing is formed in their upper part in summer. Its depth depends on landscape and climatic conditions and rock composition. In loose sediments it is minimal (no more than a meter) in the Far North and everywhere in peat. In sands it is 2 m or more. In the mountains, on bedrock, thawing reaches 3 m or even more. In river valleys, the depth of thawing varies quite significantly by short distances. With intermittent and island distribution of permafrost, seasonal thawing of frozen rocks in summer and seasonal freezing of thawed rocks in winter coexist. As a rule, wet (icy) rocks are in a frozen state and thaw relatively shallowly. The thawed rocks located nearby are often less wet, and the layer of seasonal freezing on them is thicker.

When constructing engineering structures, building railways and highways, bridges, pipelines, and hydraulic structures, it is necessary to take into account the possibility of heaving and subsidence of soils, sliding of thawing soils on slopes, and the formation of ice dams. In agriculture, permafrost in some cases limits the development of certain crops, in others it favors the cultivation of plants due to additional soil moisture during seasonal thawing of the active layer. In permafrost strata, thermodynamically unstable and therefore extremely sensitive to changes in equilibrium conditions, gas hydrates were discovered, changes in which lead to uncontrolled gas emissions, explosions, and fires, which enhances the greenhouse effect. Viable microorganisms have been discovered in frozen rocks, ice and supercooled waters, which are often involved in modern biogeochemical processes during thawing of rocks.