Lithosphere - the upper firm sheath of the Earth, gradually with a depth turning in spheres with a smaller area of \u200b\u200bthe substance. Includes the earth's bark and the upper mantle of the Earth. Power of lithosphere 50 - 200 km, including earth crust - up to 50 -75 km on continents and 5 - 10 km at the bottom of the ocean. The upper layers of the lithosphere (up to 2 - 3 km, according to some data, up to 8.5 km) are called a lithobiosphere.

The chemical composition of the earth's crust is presented in Table. 9.1.

Table 9.1. Chemical composition of the earth's crust at depths 10 - 20 km

Natural chemical compounds The elements of the earth's crust are called minerals. Of these, numerous types of rocks are consisting. The main groups of rocks are igneous, sedimentary and metamorphic.

A person practically does not affect the lithosphere, although the upper horizons of the earth's crust are exposed to severe transformation as a result of the operation of mineral deposits.

Natural resources are bodies and forces of nature that are used by a person to maintain their existence. These include sunlight, water, air, soil, plants, animals, minerals, and everything else, which is not created by a person, but without which he cannot exist as a living being or as a manufacturer.

Natural resources are classified according to the following features:

By their use - for industrial (agricultural and industrial), health (recreational), aesthetic, scientific, etc.;

On belonging to one or another components of nature - on land, aquatic, mineral, animal or vegetable world and etc.;

Under replaceability - on replaceable (for example, fuel and mineral energy resources can be replaced by wind, solar energy) and irreplaceable (respiratory oxygen or fresh water for drinking to replace with nothing);

According to exhaustion - on exhausted and inexhaustible.

The above features allow multiple classifications natural resourcesEach of which has its advantages and disadvantages. Great interest for science and practice represents the division of natural resources on the basis of exhaustibility.

Inexhaustible (inexhaustible) Resources - quantitatively inexhaustible part of natural resources (solar energy, marine tides, current water, atmosphere, although with significant pollution it can go to the category exhausted).

Exhausted - resources, the number of which is steadily decreased as they are produced or of the natural medium. They, in turn, are divided into renewable (vegetation, animal world, water, air, soil) and non-renovable (mineral). They can be exhausted as because they are not replenished as a result of natural processes (copper, iron, aluminum, etc.), and because their reserves are replenished more slowly than their consumption (oil, coal, combustible shale) occurs. Therefore, in the future, humanity will require a search for means and methods of more efficient use of non-repaired resources, including methods for processing secondary raw materials. Currently, almost all elements of the Periodic System D.I. Inendeleev are used.

The degree of application and processing of numerous types of mineral raw materials is determined by the progress and well-being of society. Major resources are metals, water, mineral and organic raw materials. The pace of operation of the earth's subsoil is accelerated from year to year. Over the past 100 years, the annual consumption of coal, iron, manganese and nickel has increased 50-60 times, tungsten, aluminum, molybdenum and potassium 200 - 1000 times.

In recent years, the mining of energy resources - oil, natural gas has increased. So, in 1991, 3340 million tons of oil were produced in the world, of which almost 40% fall into the United States, Saudi Arabia and Russia. Natural gas produced 2115 billion m 3, of which Russia accounts for 38%, on the USA - about 24%. The world has increased gold and diamond mining.

The modern era is characterized by an increasing consumption of mineral resources. Therefore, the problem of more rational use of mineral resources, which can be solved by the following methods:

The creation of new highly efficient methods of geological exploration of mineral resource-saving production methods;

Integrated use of mineral raw materials;

Reducing the loss of raw materials at all stages of mastering and using reserves of subsoil, especially at the stages of enrichment and processing of raw materials;

Creating new substances, organic synthesis of mineral raw materials.

In addition, an important role in the rational use of natural resources belongs to resource-saving technologies, which allows us to provide first of all the energy efficiency - the ratio between the energy spent and the useful product obtained at these costs. As T. Miller (1993) notes, use high-quality energy extracted from nuclear fuel, in low-quality housing - "It's like cutting oil with a circular saw or beat flies with a blacksmith hammer." Therefore, the main principle of use of energy should be the correspondence of the quality of the energy to the tasks. For housing heating, solar energy can be used, the energy of thermal sources, wind, which is already applied in some countries. In fig. 9.1 (see p. 90) shows models of two types of society: a society of one-time consumption that creates waste and a natural society.

The second type of society is the society of the future, which is based on the reasonable use of the energy and recycling of the substance, the secondary use of non-repaired resources, and also (which is especially important) there should be no excess of the environmental sustainability threshold. For example, it is much easier and cheaper to prevent pollutants from entering the natural environment, than to try to clean it from this pollution. Waste production, life, transport, etc. Can actually and potentially be used as products in other sectors of the national economy or during regeneration.

Harmful waste must be neutralized, and unused are considered to be garbage. Main types of waste are divided into domestic, production waste and production consumption.

1. Household (municipal) solid (including solid component of wastewater - their precipitate) Scrolls that are not utilized in everyday life, resulting in depreciation of household items and the lifetime itself (including bathrooms, laundry, canteens, hospitals, etc.). To destroy household waste, powerful incinerate installations or plants, which give electricity or steam, which are heating enterprises and housing.

2. Production wastes (industrial) - residues of raw materials, materials, semi-finished products formed in the production of products. They may be irrevocable (volatile, avgar, sleeping) and returned to be recycled. According to foreign sources, there are 60% of household waste in UES 60% of household waste, 33% is incinerated and 7% composed, as for industrial and agricultural waste, over 60 and 95% are intensive processing.

3. Waste production consumption - unsuitable for the further use of the machine, mechanisms, tools, etc. They can be agricultural, construction, industrial, radioactive. The latter are very dangerous and need careful disposal or deactivation.

In recent years, the number of hazardous (toxic) wastes that can cause poisoning or other lesions of living beings has increased. These are primarily not used various pesticides in agriculture, waste industrial production plants containing carcinogenic and mutagenic substances. In Russia, hazardous waste includes 10% of the mass of solid household waste, in the USA - 41%, in the UK - 3%, in Japan - 0.3%.

On the territory of many countries there are so-called "traps", that is, a long-forgotten burial of hazardous waste, at which residential buildings and other objects, which make themselves to know the emergence of strange diseases of the local population. To such "traps" can be attributed to the venue of nuclear tests for peaceful purposes. Existing projects (partly implemented) burial, as well as underground nuclear tests Can initiate the so-called "induced" earthquakes.

The highest transformation is the highest, surface horizon of the lithosphere within the sushi. Susha occupies 29.2% of the surface of the globe and includes land of various categories, of which fertile soil is essential.

Soil is a surface layer of the earth's crust that is formed and develops as a result of the interaction of vegetation, animals, microorganisms, rocks and is an independent natural education. The most important property of the soil is fertility - the ability to ensure the growth and development of plants. The soil is a giant ecological system that exercise, along with the oceans, decisive effect on the entire biosphere. It actively participates in the cycle of substances and energy in nature, maintains the gas composition of the Earth's atmosphere. By means of the soil - the most important component of biocenoses - environmental relations are carried out by living organisms with a lithosphere, hydrosphere and an atmosphere.

The founder of scientific soil is an outstanding Russian scientist V.V. Dokuchaev (1846 - 1903), which revealed the essence of the soil process. Soil factors include maternal (soil-forming) breeds, plant and animal organisms, climate, relief, time, water (soil and primer) and human economic activity. The development of the soil is inextricably linked with the mother breed (granite, limestone, sand, lessoidal loams, etc.). The formation of a loose soil mass is associated with both chemical weathered processes and biological - the formation of specific organic substances (humus or humus) under the influence of plants.

The soil includes four important structural components: a mineral base (usually 50-60% of the total soil composition), an organic substance (up to 10%), air (15-25%) and water (25 - 35%). The structure of the soil is determined by the relative content of sand in it, yals and clay. Soil chemistry is partially determined by the mineral skeleton, in part - organic matter. Most of the mineral components are represented in soil with crystal structures. Silicates are prevailing soil minerals.

A very large role in the holding of water and nutrients is played by a particularly numerous and important group of clay minerals, most of which form a colloid suspension in water. Each clay mineral crystal contains a silicate layers, combined with aluminum hydroxide layers, which have a constant negative charge, which is neutralized by cations adsorbed from the soil solution. Due to this, the cations are not leached out of the soil and can exchange other cations from soil solution and vegetable tissues. This cation exchange ability serves as one of the important indicators of soil fertility.

The organic substance of the soil is formed when the decomposition of dead organisms, their parts, excrets and feces. The final decomposition product is humus, located in a colloidal state, like clay, and having a large surface of particles with high cationic ability. Simultaneously with the formation of humus, vital elements are transmitted from organic compounds into inorganic, such as nitrogen into ammonium ions, phosphorus in orthophosphate ions, sulfur in sulfate ions. This process is called mineralization. Carbon is released in the form of CO 2 in the process of breathing.

Soil air, as well as soil water, is in the pores between soil particles. Porosity (pore volume) increases from clay to loam and sands. Between the soil and the atmosphere, free gas exchange occurs, and as a result of this, the air of both media has a similar composition, but in the air of the soil due to the respiration of its inhabiting organisms somewhat less oxygen and more carbon dioxide.

Soil particles hold around themselves some amount of water, which is divided into three types:

Gravitational water capable of freeingly leak down through the soil, which leads to leaching, that is, flushing out of the soil of various minerals;

Hygroscopic water adsorbing around individual colloidal particles due to hydrogen bonds and is the least available for plant roots. The greatest content of it in clay soils;

Capillary water held around soil particles with surface tension forces and capable of climbing by narrow and canals from groundwater levels and is the main source of water for plants (as opposed to hygroscopic, it is easily evaporated).

The soils of external signs are sharply different from rocks, due to physico-chemical processes occurring in them. They include indicators such as color (chernozem, burzems, gray forest, chestnut, etc.), structure (grainy, lumpy, columnar, etc.), neoplasia (in the steppes - calcium carbonates, in semi-deserts - gypsum accumulation). The thickness of the soil layer in moderate areas on the plains does not exceed 1.5 - 2.0 m, in the mountain - less meter.

In the soil profile, where the movements of soil solutions are dominated from top to bottom, most often allocated three main horizons:

Humus-accumulative (humus) horizon;

Eluvial, or leaching horizon, characterized mainly by the removal of substances;

The illuvial horizon where substances (easily solubular salts, carbonates, colloids, gypsum, etc.) are washed out of the overlayer horizons.

Below is the maternal (soiling) breed. Types of soils are characterized by a certain structure of the soil profile, the same type of soil formation, the intensity of the process of soil formation, properties and particle size distribution. About 100 types of soil are allocated in Russia. Among them, several main types can be distinguished:

- arctic and tundra soils, the capacity of which is no more than 40 cm. These soils are characterized by the overvailing and development of anaerobic microbiological processes, are distributed on the northern outskirts of Eurasia and North America, the islands of the Northern Ocean;

- podzolic soils, in the formation of their predominant importance is the sub-formational process in conditions of a temperate wet climate under coniferous forests of Eurasia and North America;

- chernozem Distributed within the limits of the forest-steppe and steppe zones of Eurasia are formed in conditions of arid climate and increasing continentality, are characterized by a large amount of humus (\u003e 10%) and are the most fertile type of soil;

- chestnut soils characterized by a slight content of humus (< 4%), формируются в засушливых и экстраконтинентальных условиях сухих степей, широко используются в земледелии, так как обладают плодородием и содержат достаточное количество элементов питания;

- gray-brown soils and serozia Typical for plain intra-engine deserts moderate belt, subtropical deserts of a moderate belt, subtropical deserts of Asia and North America, develop under dry continental climate conditions and differ in high saline and low humus content (up to 1.0 - 1.5%), low fertility and suitable for farming only under irrigation conditions;

- red 19 and yellowemes form in the conditions of subtropical climate under wet subtropical forests, are common in South-East Asia, on the coast of the Black and Caspian Seas, this type of soil during agricultural use requires the introduction of mineral fertilizers and the protection of soil from erosion;

- hydromorphic soils Form under the influence of atmospheric moisture of surface and groundwater, common in forest, steppe and desert zones. These include swampy and saline soils.

The main chemical and physical properties characterizing soil fertility are:

Indicators of the physical properties of the soil - density, aggregation, field moisture intensity, water permeability, aeration;

The morphological structure of the soil profile is the power of the arable horizon and the general humus profile;

Physico-chemical properties of soil is the soil reaction, the absorption capacity, the composition of exchange cations, the degree of saturation of the bases, the level of toxic substances - the movable forms of aluminum and manganese, salt regime indicators. Chemical soil pollution leads to the degradation of soil-vegetation cover and a decrease in soil fertility.

Soil mortar - This is a solution of chemicals in water, located in equilibrium with solid and gaseous phases of the soil and the pink space filling it. It can be considered as a homogeneous liquid phase having a variable composition. The composition of the soil solution depends on its interaction with solid phases as a result of the processes of dissolution, sorption-desorption, ion exchange, complexation, dissolving the gases of soil air, the decomposition of animals and plant residues.

The quantitative characteristics of the composition and properties of the soil solution are ionic, mineralized, electrical conductivity, oxidation and reduction potential, titratable acidity (alkalinity), activity and concentration of ions, pH. Chemical elements can be part of the soil solution in the form of free ions, aquacomplexes, hydrox complexes, complexes with organic and inorganic ligands, in the form of ion pairs and other associates. Soil solutions of different types of soils have carbonate, hydrocarbonate, sulphate or chloride anionic composition with a predominance among CA, MG, K, NA cations. Depending on the degree of mineralization, which is found as the sum of dry salts after evaporation of the soil solution (in mg / l), the soil is classified into fresh, brass and salty (Table 9.2).

Table 9.2. Classification of natural waters (soil solutions) depending on their mineralization

An important characteristic of the soil solution is the relevant acidity, which is characterized by two indicators: the activity of ions H + (degree of acidity) and the content of acidic components (the amount of acidity). The magnitude of the pH of the soil solution is influenced by free organic acids: wine, ant, oil, cinnamon, acetic, fulvironment and others. Mineralic acids great importance It has coalic acid, by the amount of which is affected by dissolving in soil solution of CO 2.

Only due to CO 2 pH of the solution can decrease to 4-5.6. In terms of current acidity, the soil is classified on:

sylnic acid pH \u003d 3-4; weakly alkaline pH \u003d 7-8;

acid pH \u003d 4-5; alkaline pH \u003d 8-9;

weakness pH \u003d 5-6; Eliminate pH \u003d 9-11.

neutral pH \u003d 7;

Excess acid is toxic for many plants. A decrease in the pH of the soil solution causes an increase in the mobility of aluminum, manganese, iron, copper and zinc ions, which causes a decrease in enzyme activity and deterioration of the properties of plants protoplasm and leads to damage to the root system of plants.

The ion exchange properties of the soil are associated with the equivalent exchange process in the soil absorbing complex of cations and anions of the interacting with solid phases of the soil solution. The main part of the metabolic anions is in the soils on the surface of iron and aluminum hydroxides, which are positive charge under an acidic reaction. In the exchange form in the soil, anions CL -, NO 3 -, SEO 4 -, Moo 4 2-, Hmoo 4 can be present. Exchange phosphate, arsenate and sulfate ions may be contained in soils in small quantities, since these anions are firmly absorbed by some components of the solid soil phases and are not supplied to the solution when exposed to other anions. Absorption of anions with soils in adverse conditions can lead to the accumulation of a number of toxic substances. Exchange cations are located on the exchange positions of clay minerals and organic matter, their composition depends on the type of soil. In the tundra, podzolic, brown forest soils, reds and yellow meters among these cations, al 3+, Al (OH) 2+, Al (OH) 2 + and H + ions are dominated among these cations. In chernozem, chestnut soils and serosms, the exchange processes are predominantly predominantly by the ions of Ca 2+ and Mg 2+, and in saline soils - also Na + ions. In all soils among exchange cations there is always no a large number of ions to +. Some heavy metals (Zn 2+, Pb 2+, CD 2+, etc.) may be present in soils as metabolic cations.

To improve the soil in order to agricultural production, a system of events called amelioration is carried out. Melioration includes: drainage, irrigation, indulgence of waste, abandoned lands and swamps. As a result of the amelioration, especially many wetlands are lost, which contributed to the process of extinction of species. Conducting measures for indioraority often leads to a collision of the interests of agriculture and nature conservation. The decision to conduct amelioration should be taken only after the comprehensive environmental rationale and comparison of short-term benefits with long-term national economic costs and environmental damage. The amelioration is accompanied by the so-called secondary soil salinization, which is due to the artificial change of the water-salt regime, most often with irrigated irrigation, less often - with an unlimited grazing in the meadows, with improperly regulating floods, improperly draining the territory, etc. Salmon is accumulated in soils of easily soluble salts. In natural conditions, it occurs due to the loss of salts from saline groundwater or in connection with the eoliac bridge of salts from the seas, the oceans and from the territories where salted lakes are widespread. On irrigated arrays, irrigation waters can be an essential source of salts and salts in the soil thickness of mineralized groundwater, the level of which during irrigation often rises. In case of insufficient drainage, the secondary salinization can have catastrophic consequences, since the extensive land arrays become unsuitable for agriculture due to the large accumulation of salts in soils accompanied by soil contamination with heavy metals, pesticides, herbicides, nitrates, boron compounds.

Pesticides are chemical substancesused to destroy certain harmful organisms. Depending on the direction of use, they are divided into several groups.

1. Herbicides (Duron, Simazine, Atrazin, Mongurone, etc.), used to combat weed plants.

2. Algicides (copper sulfate and its complexes with alkanoamine, acrolein and its derivatives) - to combat algae and other water vegetation.

3. Arboricides (Kayafenon, Kusagard, Plyeron, Thhan, Trisben, Lontrail, etc.) - to destroy unwanted wood and shrub vegetation.

4. Fungicides (cinb, captain, phtalan, dat, chlorotalonyl, benomyl, carboxin) - to combat fungal diseases of plants.

5. Bactericides (salts of copper, streptomycin, bronopol, 2-trichlorometheyl-6-chloropyridine, etc.) - to combat bacteria and bacterial diseases.

6. Insecticides (DDT, Lindane, Dillrin, Aldry, Chlorofos, Diffos, Carbofos, etc.) - to combat harmful insects.

7. Acaricides (Brompropylate, Dicofol, Dinobuton, Dnock, Tetradiphon) - to combat ticks.

8. Zoocides (Rativeycides, Raticides, Avicides, ichthyocides) - to combat harmful spine - rodents (mice and rats), birds and weed fish.

9. Limacides (Metaldehyde, Methiocarb, Triphenmorph, Niklosamid) - to combat mollusks.

10. Nematocides (DD, DDB, Trapex, Carbation, Tiazon) - to combat round worms.

11. Affer - to deal with troubles.

Pesticides also include chemical tools for stimulating and braking plant growth, drugs for removing leaves (defoliates) and plant drying (desiccants).

Actually pesticides (valid beginnings) - natural or most often synthetic substances that are not in pure form, but in the form of various combinations with diluents and surfactants. There are several thousand active ingredients, about 500 are constantly used. The range is constantly updated, which is due to the need to create more efficient and secure pesticides for people and the environment, as well as developing insects, ticks, fungi and resistance bacteria with long-term use of alone and those same pesticides.

The main characteristics of pesticides are activity in relation to targeted organisms, selectivity of action, safety for people and the environment. The activity of pesticides depends on their ability to penetrate the body, move in it to the place of action and suppress vital processes. Selectivity depends on differences in biochemical processes, enzymes and substrates in organisms of different types, as well as from the doses used. The environmental safety of pesticides is associated with their selectivity and the ability to maintain some time in the medium without losing its biological activity. Many pesticides are toxic for people and warm-blooded animals.

Chemical compounds used as pesticides belong to the following classes: Phosphorganic compounds, chlorine derivatives of hydrocarbons, carbamates, chlorophenolic acids, urea derivatives, amides carboxylic acids, nitro and halonefenols, dinitroanilines, nitrodiphenyl ethers, halogenyliphatic and aliphatic acids, aryloxyalkarboxylic acids, aromatic and heterocyclic acids, derivatives of amino acids, ketones, five- and hexted heterocyclic compounds, triazines, etc.

The use of pesticides in agriculture helps to increase its productivity and reduce losses, but it is associated with the possibility of residual pesticides in food and environmental danger. For example, the accumulation of pesticides in the soil, entering into ground and surface water, violation of natural biocenoses, harmful effects on the health of people and fauna.

The most danger is resistant pesticides and their metabolites that can accumulate and persist in natural environment up to several decades. Under certain conditions, second-order metabolites are formed from pesticide metabolites, the role, and the influence of which on the environment in many cases remain unknown. The consequences of the non-harmony use of pesticides can be the most unexpected, and most importantly, biologically unpredictable. Therefore, hard control is installed behind the assortment and technique of application of pesticides.

Pesticides are affected by various components of natural systems: reduce the biological productivity of phytocenoses, the species diversity of the animal world, reduce the number of useful insects and birds, and ultimately be dangerous for humans. It is estimated that 98% of insecticides and fungicides, 60-95% of herbicides do not reach the suppression objects, and enter the air and water. Zoocides create a lifeless environment in the soil.

Pesticides containing chlorine (DDT, hexachlororan, dioxin, dibenzfuran, etc.) differ not only to high toxicity, but also emergency biological activity and the ability to accumulate in various stars of the food chain (Table 9.3). Even in insignificant quantities of pesticides, the immune system of the body is suppressed, thus increasing its sensitivity to infectious diseases. In higher concentrations, these substances have a mutagenic and carcinogenic effect on the human body. Therefore, recently, pesticides with low flow rate (5-50 g / ha) are most important, the distribution is obtained by safe synthetic pheromones and other biological protection methods.

Table 9.3. DDT biological strengthening (according to P. Revelly, Ch. Revelly, 1995)

World pesticide production is about 5 million tons. Increasing the volume of application of pesticides is explained by the fact that environmentally safer alternative methods of plant protection are not well developed, especially in the field of weed control. All this determines the special relevance of the detailed and comprehensive study and prediction of all sorts of changes arising in the biosphere under the influence of these substances. The development of effective measures to prevent the unwanted consequences of intensive chemicalization, or to manage the functioning of ecosystems under pollution conditions is necessary.

To increase the yield of cultivated plants in the soil they bring inorganic and organic substances, called fertilizers. In natural biocenosis, natural cycle of substances is dominated: mineral substances taken by plants from the soil, after dying the plants, return to it again. If, as a result of the alienation of the crop for its own consumption or for sale, the system is violated, it becomes necessary to apply fertilizers.

Fertilizers are divided into minerals mined from subsoil, or industrially obtained chemical compounds containing basic nutrition elements (nitrogen, phosphorus, potassium) and microelements (copper, boron, manganese, etc.), as well as organic components (humid, manure , peat, bird litter, composts, etc.), contributing to the development of useful soil microflora and boosting fertility.

However, fertilizers are made in quantities that are not balanced with the consumption of agricultural plants, therefore they become powerful sources of soil pollution, agricultural products, soil soil waters, as well as natural reservoirs, rivers, atmospheric. The use of excess mineral fertilizers may have the following negative consequences:

Change soil properties with long-term fertilizers;

Making large amounts of nitrogen fertilizers leads to soil contamination, agricultural products and freshwater nitrates, and atmospheres - nitrogen oxides. All of the above concerns and phosphoric fertilizers;

Mineral fertilizers serve as a source of soil pollution with heavy metals. The most contaminated with heavy metals phosphoric fertilizers. In addition, phosphoric fertilizers are a source of pollution by other toxic elements - fluorine, arsenic, natural radionucleides (uranium, thorium, radium). A significant amount of heavy metals falls into the soil and with organic fertilizers (peat, manure), due to high doses (compared to mineral).

The step-fertilization leads to high content of nitrates in drinking water and some cultures (root vegetables and leaf vegetables). Nutrates themselves are relatively non-toxic. However, bacteria living in the human body can turn them into much more toxic nitrites. The latter are capable of reacting in the stomach with amines (for example, from cheese), forming very carcinogenic nitrosoamines. The second danger of elevated doses of nitrite is related to the development of cyanosis (infant methemoglobinemia or sinusiness) in infant and small children. The maximum permissible quantities (MPC) of nitrates for a person, according to the recommendation of the WAO, should not exceed 500 mg N - NO 3 - per day. The World Health Organization (WHO) admits the content of nitrates in products up to 300 mg per 1 kg of raw material.

Thus, excessive involvement of nitrogen compounds in the biosphere is very dangerous. To reduce negative consequences, it is advisable to use the joint introduction of organic and mineral fertilizers (with a decrease in the norm of mineral and increasing the share of organic fertilizers). It is necessary to prohibit fertilizers in the snow, from airplanes, reset the waste of animal husbandry into the environment. It is advisable to develop forms of nitrogen fertilizers at a low dissolution rate.

To prevent soil pollution and landscapes various elementsAs a result of applying fertilizers, a complex of agrotechnical, agro-celloic and hydraulic techniques should be applied in combination with the intensification of natural cleaning mechanisms. Such techniques can be attributed to the instructional agricultural engineering, minimal processing of soils, improve the range of chemicalization tools, little - and microbinization of fertilizers together with seeds, optimization of terms and doses of application. In addition, this will be facilitated by the creation of agro-component systems and the organization of a system of chemical control over the composition of mineral fertilizers, the content of heavy metals and toxic compounds.

Plan

Ground Bark (mainland, oceanic, transitional).

The main components of the earth's crust are chemical elements, minerals, rocks, geological bodies.

Basics of the classification of magmatic rocks.

Ground Bark (mainland, oceanic, transitional)

Based on these depth seismic probes in the thickness of the earth's crust, a number of layers are distinguished, characterized by different speeds of passing elastic oscillations. Three of these layers are considered the main. The most upper one is known as a sedimentary shell, the average - granite-metamorphic and lower - basalt (Fig.).

Fig. . The scheme of the structure of the crust and the upper mantle, including a solid lithosphere

and plastic asthenosphere

Sedimentary layer Complicated mainly the most soft, loose and more dense (due to cementation of loose) rocks. Sedimentary breeds are usually located in the form of layers. The power of the sedimentary layer on the surface of the Earth is very impermanent and varies from several m to 10-15 km. There are plots where the sedimentary layer is completely absent.

Granite-metamorphic layer Folded mainly magmatic and metamorphic rocks, rich aluminum and silicon. Places where there is no sedimentary layer and the granite layer goes to the surface crystal shields (Kola, Anabar, Alandansky, etc.). The power of the granite layer is 20-40 km, there are no places in places (at the bottom of the Pacific Ocean). According to the study of the seismic waves, the density of rocks at the bottom bound from 6.5 km / s to 7.0 km / s change dramatically. This boundary of the granite layer separating the granite layer from basalt got a name borders of the conrad.

Basalt layer It stands out at the base of the earth's crust, there is everywhere, its power ranges from 5 to 30 km. The density of the substance in the basalt layer - 3.32 g / cm 3, in composition, it differs from granites and is characterized by a significantly smaller content of silica. At the lower boundary of the layer, there is a jump-shaped change in the speed of passing longitudinal waves, which indicates a sharp change in the properties of rocks. This border is accepted for the lower boundary of the earth's crust and is named the border of Mochorovichi, as mentioned above.

In various parts of the globe, the earth's crust is heterogeneous both in terms of composition and in power. Types of earthbow - material or continental, oceanic and transition. The oceanic cake occupies about 60%, and the continental about 40% of the earth's surface, which differs from the distribution of the ocean area and land (71% and 29%, respectively). This is due to the fact that the border between the types of the bark under consideration passes along the continental foot. Shallow Seas, such as, for example, the Baltic and Arctic seas of Russia, belong to the Ocean only from a geographical point of view. In the field of oceans allocate ocean typecharacterized by a low-power sedimentary layer under which basalt is located. Moreover, the ocean bark is much younger than continental - the age of the first is not more than 180 - 200 million years. The earth's edge under the continent contains all 3 layers, has a greater power (40-50 km) and is called mainland. The transition bark corresponds to the underwater edge of the mainland. In contrast to the continental, the granite layer is sharply reduced here and it goes down to the ocean, and then there is a reduction in the power of the basalt layer.

The sedimentary, granite-metamorphic and basalt layers together form a shell, which received the name of Siole - from words of silicium and aluminum. It is usually believed that in a sialic shell it is advisable to identify the concept of earthly crust. It was also established that throughout the geological history, the earth's crust absorbs oxygen and it consists of 91% by volume.

The main components of the earth's crust - chemical elements, minerals, rocks, geological bodies

The substance of the Earth consists of chemical elements. Within stone shell Chemical elements form minerals, minerals are laying rock rocks, and rocks in turn are geological bodies. Our knowledge of the chemistry of land, or otherwise geochemistry, catastrophically decrease with depth. Deeper 15 km our knowledge is gradually replaced by hypotheses.

American chemist F.V. Clark together with GS Washington, starting at the beginning of the last century, the analysis of various breeds (5159 samples) published data on the average content of about ten the most common elements in the earth's crust. Frank Clark proceeded from that position that the solid earthbow to a depth of 16 km consists of 95% of the erupted rocks and 5% of the sedimentary rocks formed by the erupted. Therefore, to count F. Klark used 6000 analyzes of various rocks, taking their arithmetic average. In the future, these data was supplemented by the average content of the contents of other elements. It turns out that the most common elements of the earth's crust are (wt.%): O - 47.2; Si - 27.6; Al - 8.8; Fe - 5.1; Ca - 3.6; Na - 2.64; Mg - 2.1; K - 1.4; H - 0.15, which in sum is 99.79%. These elements (except hydrogen), as well as carbon, phosphorus, chlorine, fluorine and some others are called breed-forming or petrogenic.

Subsequently, these figures were repeatedly specified by various authors (Table).

Comparison of various estimates of the composition of the earth's crust of continents,

The average mass fractions of chemical elements in the earth's crust were called at the suggestion of Academician A. E. Fesman clarkov. The latest data on the chemical composition of the areas of the Earth is reduced to the following scheme (Fig.)

All the substance of the earth's crust and the mantle consists of minerals, diverse in shape, structure, composition, prevalence and properties. Currently, more than 4,000 minerals are allocated. It is impossible to call the exact number because annually the number of mineral species is replenished with 50-70 naming of mineral species. For example, about 550 minerals are open on the territory of the former USSR (in the museum. A.E.Fersman is stored 320 species), of which more than 90% in the twentieth century.

The mineral composition of the earth's crust looks like this (vol.%): Field Ploves - 43.1; Pyroxes - 16.5; Olivine - 6.4; amphiboles - 5.1; mica - 3.1; clay minerals - 3.0; orthosilicates - 1.3; chlorite, serpentines - 0.4; quartz - 11.5; Cristobalitis - 0.02; Tridimitis - 0.01; Carbonates - 2.5; ore minerals - 1.5; phosphates - 1.4; Sulfates - 0.05; iron hydroxides - 0.18; Others - 0.06; Organic substance - 0.04; Chlorides - 0.04.

These numbers, of course, are very relative. In general, the mineral composition of the earth's crust is the most PEST and rich in comparison with the composition of deeper geophage and meteorites, the substances of the moon and the external shells of other planets of the earth group. So the moon revealed 85 minerals, and in meteorites - 175.

Natural mineral aggregates, aligning independent geological bodies in the earth's crust are called rocky rocks. The concept of "geological body" is a different-scale concept, it includes volumes from the mineral crystal to continents. Each rock formation forms a bulk body in the earth's crust (layer, lens, array, cover ...), characterized by a certain real composition and a specific indoor structure.

In Russian Geological Literature, the term "mining breed" was introduced in the late XVIII century Vasily Mikhailovich Sevgyn. The study of the earth's crust showed that it was composed of various rocks, which by origin can be divided into 3 groups: igneous or erupted, sedimentary and metamorphic.

Before moving to the description of each of the groups of rocks separately, it is necessary to stop on their historical relationships.

It is believed that initially the globe represented the molten body. From this primary melt or magma, and was formed by cooling the solid earthly bark, at the beginning of the whole magmatic mountain rocks, which should be considered as historically the most ancient group of rocks.

Only in the later phase of the development of the earth could have breeds of other origin. This became possible after the occurrence of all the external shells: the atmosphere, the hydrosphere, the biosphere. Primary magmatic rocks under their impact and solar energy were destroyed, the destroyed material was moved with water and wind, was sorted and recently cemented. So there were sedimentary rocks, which are secondary to the magmatic, at the expense of which they were formed.

Material for the formation of metamorphic rocks, both magmatic rocks and sedimentary are served. As a result of various geological processes, the lamination of large sections of the earth's crust occurred, the accumulation of sedimentary breeds was accumulated within these sites. The lower parts of the thickness during these omens fall into all high depths in the area of \u200b\u200bhigh temperatures and pressures, in the region of penetration from the magma of various vapors and gases and circulation of hot water solutions, bringing new chemical elements to breed. The result is metamorphism.

The spread of these rocks is not the same. It is estimated that a lithosphere is 95% complexed by igneous and metamorphic rocks and only 5% are sedimentary rocks. On the surface the distribution is somewhat different. Sedimentary rocks covered 75% ground surface And only 25% accounted for the share of magmatic and metamorphic rocks.

Earth's crust - The thin upper sheath of the Earth, which has a thickness on the continents of 40-50 km, under the oceans -5-10 km and is only about 1% of the mass of the Earth.

Eight elements - oxygen, silicon, hydrogen, aluminum, iron, magnesium, calcium, sodium - form 99.5% of the earth's crust.

On continents, three-layer bark: sedimentary breeds cover granite, and the granites are locked in basalt. Under the oceans bark "Oceanic", two-layer type; The sedimentary rocks are simply locked in basalts, there is no granite layer. The transitional type of the earth's crust (island arc zones on the outskirts of the oceans and some areas on the mainland, for example), are also distinguished.

The largest thickness of the earth Cora has in mountainous areas (under the Himalayas - over 75 km), the average - in the areas of platforms (under the West Siberian Nynsina - 35-40, within the borders of the Russian platform - 30-35), and the smallest-in central regions of the oceans (5-7 km).

The prevailing part of the earth's surface is the plains of the continents and the oceanic bottom. The continents are surrounded by a shallow strip of a depth of 200 g and an average wide width of SO km, which after a sharp breakdown of the bottom goes into the continental slope (the slope changes from 15-17 to 20-30 °. ). The slopes are gradually aligned and transferred to the abissual plains (depth of 3.7-6.0 km). The greatest depths (9-11 km) have oceanic chute, the overwhelming majority of which are located on the North and Western outskirts.

The earth's crust was generated gradually: first the basalt layer was formed, then the granite, the sedimentary layer continues to be formed and at present.

The deep thickness of the lithosphere, which are investigated by geophysical methods, have a rather complicated and not yet sufficiently studied structure, as well as mantle and the core of the Earth. But it is already known that with a depth density of rocks increase, and if it is an average of 2.3-2.7 g / cm3 on the surface, then at a depth of 400 km - 3.5 g / cm3, and at a depth of 2900 km ( The border of the mantle and the outer kernel) is 5.6 g / cm3. In the center of the nucleus, where the pressure reaches 3.5 thousand t / cm2, it increases to 13-17 g / cm3. The nature of the increase in the deep temperature of the earth is also established. At a depth of 100 km, it is approximately 1300 K, at a depth of 3000 km -4800 K, and in the center of the earth's core - 6900 K.

The predominant part of the substance of the Earth is in a solid state, but on the border of the earth's crust and the upper mantle (depth of 100-150 km), the thickness of softened, tough rock rocks occurs. This thickness (100-150 km) is called an asthenosphere. Geophysics believe that other areas of the Earth may be located in a rarefied state (due to the decompression, the active radiosset of rocks, etc.), in particular, the zone of the outer kernel. The inner core is in the metallic phase, but there is no uniform opinion on its real composition for today.

The position of the earth's crust between mantle and external shells - atmosphere, hydrosphere and biosphere - determines the impact on it by the external and internal forces of the Earth.

The structure of the earth's crust is heterogeneously (Fig. 19). Top layer whose power ranges from 0 to 20 km, complicated sedimentary rocks - sand, clay, limestones, etc. This is confirmed by the data obtained in the study of expansion and core of drilling wells, as well as the results of seismic studies: these rocky rocks, the rate of passage of seismic waves is small.

Fig. nineteen.The structure of the earth's crust

Below, under the mainland, is located granite layerfolded by rocks whose density corresponds to the density of granite. The speed of seismic waves in this layer, as in granites, is 5.5-6 km / s.

Under the oceans, the granite layer is absent, and in the continent in some places it goes to the day surface.

Even below, there is a layer in which seismic waves apply at a speed of 6.5 km / s. This speed is characteristic of basalt, therefore, despite the fact that the layer is composed with different rocks, it is called basalt.

The boundary between granite and basalt layers is called surface Conrad . This section corresponds to the jump rate of seismic waves from 6 to 6.5 km / s.

Depending on the structure and power, two types of bark are distinguished - mainlandand oceanic.Under the continents, the bark contains all three layers - sedimentary, granite and basalt. Its power on the plains reaches 15 km, and in the mountains increases to 80 km, forming the "roots of the mountains." Under the oceans, the granite layer is absent in many places, and basalts are covered with a thin case of sedimentary rocks. In the deep-sea parts of the ocean, the power of the cortex does not exceed 3-5 km, and the upper mantle lies below.

Mantle.This is an intermediate shell located between the lithosphere and the core of the Earth. The lower border is presumably at a depth of 2900 km. The mantle accounts for more than half of the volume of land. The mantle substance is in an overheated state and is experiencing a huge pressure of the overlying lithosphere. Mantle has a great influence on the processes occurring on Earth. In the upper mantle, magmatic foci occur, ores, diamonds and other fossils are formed. From here it comes to the surface of the earth. The substance of the upper mantle is constantly and actively moved, causing the movement of the lithosphere and the earth's crust.

Core.The kernel distinguish between two parts: external, to the depth of 5 thousand km, and the inner, to the center of the Earth. The external kernel is liquid, since transverse waves are not passing through it, the inner is solid. The substance of the nucleus, especially internal, is strongly sealed and in density corresponds to metals, so it is called metal.

The physical properties of the Earth include temperature regime (internal heat), density and pressure.

The inner heat of the Earth.According to modern ideas, the Earth after its formation was a cold body. Then the decay of radioactive elements gradually warmed it. However, as a result of radiation of heat from the surface in the near-earth space, it was cooling. A relatively cold lithosphere and earth bark were formed. At great depth and today high temperatures. The increase in temperatures with depth can be observed directly in deep mines and drilling wells, during volcanic eruptions. So, the plowing volcanic lava has a temperature of 1200-1300 ° C.

On the surface of the Earth, the temperature is constantly changing and depends on the influx sun heat. Daily fluctuations of temperatures are distributed to a depth of 1-1.5 m, seasonal - up to 30 m. Below this layer is the area of \u200b\u200bconstant temperatures, where they always remain unchanged and correspond to the average annual temperatures of this area on the ground surface.

The depth of the area of \u200b\u200bpermanent temperatures in different places is not the same and depends on the climate and thermal conductivity of rocks. Below this zone begins an increase in temperature, on average by 30 ° C every 100 m. However, this value is inconsistent and depends on the composition of rocks, the presence of volcanoes, the activity of thermal radiation from the depths of the Earth. So, in Russia, it ranges from 1.4 m in Pyatigorsk to 180 m at the Kola Peninsula.

Knowing the radius of the Earth, it is possible to calculate that in the center its temperature should reach 200,000 ° C. However, at such a temperature, the Earth would turn into a hot gas. It is believed that the gradual increase in temperatures occurs only in the lithosphere, and the upper mantle serves the source of the inner heat of the Earth. Below the temperature increases slows down, and in the center of the Earth it does not exceed 50,000 ° C.

Earth density.The denser the body, the greater the mass of its volume. The reference of the density is considered to be water, 1 cm 3 of which weighs 1 g, i.e. the water density is 1 g / s 3. The density of other bodies is determined by the ratio of their mass to the mass of water of the same volume. Hence it is clear that all the bodies having a density of more than 1 are drowning, less - swim.

The density of the Earth in different places is not the same. Sedimentary breeds have a density of 1.5-2 g / cm 3, and basalts are more than 2 g / cm 3. The average density of the Earth is 5.52 g / cm 3 - this is 2 times more than the density of granite. In the center of the Earth, the density of the foundations of its rocks increases and is 15-17 g / cm 3.

Pressure inside the Earth.Mountain breeds in the center of the Earth have tremendous pressure from the overlying layers. It is estimated that at a depth of only 1 km, the pressure is 10 4 GPa, and in the upper mantle it exceeds 6 * 10 4 GPa. Laboratory experiments It is shown that at such a pressure, solids, such as marble, bend and can even flow, that is, the properties are acquired, intermediate between solid and liquid. This state of substances is called plastic. This experiment suggests that in the deep depths of the land of the matter is in a plastic state.

Chemical composition of the Earth.In the ground, you can find all the chemical elements of the Table D. I. Mendeleev. However, the number of them is different, they are distributed extremely unevenly. For example, in the earth's crust, oxygen (o) is more than 50%, iron (Fe) is less than 5% of its mass. It is estimated that basalt and granite layers consist mainly of oxygen, silicon and aluminum, and the share of silicon, magnesium and iron increases into the mantle. In general, it is believed that on 8 elements (oxygen, silicon, aluminum, iron, calcium, magnesium, sodium, hydrogen) account for 99.5% of the composition of the earth's crust, and all other are 0.5%. Data on the composition of the mantle and the nucleus are presumptive.

The earth's crust only seems fixed, absolutely stable. In fact, it makes continuous and varied movements. Some of them occur very slowly and are not perceived by the human senses, others, such as earthquakes, are oblivious, destructive. What are the titanic forces lead to the earth's crop?

Internal forces of the Earth, the source of their origin. It is known that at the border of the mantle and lithosphere, the temperature exceeds 1500 ° C. At this temperature, matter should either melt or turn into gas. During the transition solid tel In a liquid or gaseous state, the volume should increase them. However, this does not occur, since the superheated rocks are under the pressure of the overlying layers of the lithosphere. The effect of the "steam boiler" occurs when the Matter's aspiring expand to the lithosphere, leading it to move along with the earth's crust. At the same time, the higher the temperature, the stronger the pressure and the more actively the lithosphere is moving. Particularly strong foci of pressure occur in those places of the upper mantle, where radioactive elements are concentrated, the decay of which heats up the considerations to even higher temperatures. The movements of the earth's crust under the influence of the internal forces of the Earth are called tectonic. These movements are divided into oscillatory, folding and discontinuous.

Oscillatory movements.These movements occur very slowly, imperceptibly for a person, so they are also called centuriesor ePEirogenic.In some places, the earth is rises, in others, it is lowered. At the same time, it is often replaced by lowering, and vice versa. You can follow these movements only by the "tracks" that remain after them on the earth's surface. For example, on the coast of the Mediterranean Sea, near Naples, there are ruins of the temple of serapis, the columns of which are sources from sea mollusks at an altitude of up to 5.5 m above the modern sea level. This serves as an unconditional proof that the temple built in the IV century, visited the day of the sea, and then his raise occurred. Now this section of Sushi is again falling. Often on the coasts of the seas above their modern level There are steps - sea terraces created by once the sea. At the sites of these steps you can find the remnants of marine organisms. This suggests that the terraces are once the bottom of the sea, and then the coast rose and the sea retreated.

The lowering of the earth's crust below 0 m above sea level is accompanied by the onset of the sea - transgressionand raising - his retreat - regression.Currently, in Europe, raising occurs in Iceland, Greenland, on the Scandinavian Peninsula. The observations found that the region of the combat bay rises at a speed of 2 cm per year, i.e., 2 m in the century. At the same time, the territory of Holland, South England, Northern Italy, the Black Sea lowland, the coast of the Kara Sea occurs. A sign of the lowering of marine coasts is the formation of marine bays in the wellhead sites of the rivers - Estairiev (lips) and Limanov.

When raising the earth's crust and the retreat of the sea, the seabed, folded by sedimentary rocks, turns out to be land. So form extensive sea (primary) plains:for example, West Siberian, Turan, North-Siberian, Amazonian (Fig. 20).

Fig. twenty.The structure of primary, or marine, reservoir plains

Formation movements.In cases where the layers of rocks are sufficiently plastic, under the action of the internal forces, they are crushed into a fold. When the pressure is directed vertically, the rocks are displaced, and if in the horizontal plane, they are compressed into the folds. The fold form is the most diverse. When the bending of the folds are directed down, it is called syncline, up - anticline (Fig. 21). Folds at high depths, i.e., at high temperatures and high pressure, and then under the action of internal forces, they can be raised. So arise folded mountainsCaucasian, Alps, Himalayas, Andes, etc. (Fig. 22). In such mountains, folds are easy to observe where they are naked and overlook.

Fig. 21.Sinclothal (1) And anticlinal (2) folds

Fig. 22.Folded mountains

Disapproving movements.If rock rocks are not durable enough to withstand the effect of internal forces, cracks are formed in the earth's crust - faults and vertical displacement of rocks. The lowered areas are called robinand risks - gorestami(Fig. 23). Alternation of horschers and rabes creates hollow (revived) mountains.Examples of such mountains serve: Altai, Sayan, Verkhoyansky ridge, Appalachi in North America and many others. The revived mountains differ from folded both by the inner structure and appearance - morphology. The slopes of these mountains are often sheer, valleys, like watersheds, wide, flat. The layers of rocks are always shifted relative to each other.

Fig. 23.Restricted fold-bully mountains

The lowered areas in these mountains, rabes, are sometimes filled with water, and then deep lakes are formed: for example, Baikal and Teletskoy in Russia, Tanganyika and Nyas in Africa.

With a further increase in temperature in the depths of the Earth, rock rocks, despite the high pressure, melted, forming magma. This highlights a lot of gases. It further increases the volume of the melt, and its pressure on the surrounding rocks. As a result, a very dense, magma-saturated gases seeks to where the pressure is less. It fills the cracks in the earthly crust, breaks and lifts the layers of their rocks. A part of the magma, without reaching the earth's surface, is frozen in the thickness of the earth's crust, forming magmatic veins and laccolites. Sometimes magma is pulled out to the surface, and its eruption occurs in the form of lava, gases, volcanic ashes, thresholds of rocks and frozen lava bunches.

Volcanoes.Each volcano has a channel for which the lava is eruption (Fig. 24). it zherlowhich always ends with a funk-shaped expansion - crater.The diameter of the crater varies from several hundred meters to many kilometers. For example, the diameter of the Vesuvius crater is 568 m. Very large crater are called calderars. For example, the caldera of the rose volcano on Kamchatka, which fills the lake Kronotsky, reaches 30 km in the diameter.

The shape and height of the volcanoes depend on the viscosity of the lava. Liquid lava quickly and easily spreads and does not forms the mountains of a cone-shaped form. An example is the Kilaruz volcano on the Hawaiian Islands. The crater of this volcano is a rounded lake with a diameter of about 1 km filled with a bubble liquid lava. Lava level, like water in a spherian bowl, then descends, then rises, splashing through the edge of the crater.

Fig. 24.Volcanic cone

Volcanoes with a viscous lava are widespread, which, cooling, forms a volcanic cone. The cone always has a layered structure, which indicates that the outpouring occurred many times, and the volcano grew gradually, from eruption to the eruption.

The height of volcanic cones ranges from several tens of meters to several kilometers. For example, Akonkagua Volcano in Andes has a height of 6960 m.

Mountain volcanoes, acting and extincting, there are about 1500. Among them are such giants like Elbrus in the Caucasus, Klyuchevskaya Natka in Kamchatka, Fujiima in Japan, Kilimanjaro in Africa and many others.

Most of the existing volcanoes are located around Pacific Ocean, forming the Pacific "Fire Ring", and in the Mediterranean-Indonesian belt. Only in Kamchatka there are 28 active volcanoes, and all of their more than 600. The existing volcanoes are spread naturally - all of them are confined to the movable zones of the earth's crust (Fig. 25).

Fig. 25Zones of volcanism and earthquakes

In the geological past, Vulcanism was more active than now. In addition to the usual (central) eruptions, fractured outpouring occurred. From giant cracks (faults) in the earth's crust stretching for dozens and hundreds of kilometers, Lava was erupted onto the earth's surface. Created solid or spotted lava covers, leveling terrain. The lava thick reached 1.5-2 km. So formed lava plains.An example of such plains serve individual sections of the medium-grained plateau, the central part of the decan plate in India, Armenian Highlands, Columbia Plateau.

Earthquake.The causes of earthquakes are different: volcanic eruption, collaps in the mountains. But the strongest of them arise as a result of the movements of the earth's crust. Such earthquakes are called tectonic.They usually be born at great depth, on the border of the mantle and lithosphere. The place of the origin of the earthquake is called gipocenter.or the hearth.On the surface of the earth, above the hypocenter, is located epicenterearthquake (Fig. 26). Here the earthquake power is the greatest, and when removing from the epicenter, it weakens.

Fig. 26.Gypocenter and Earthquake Epicenter

Ground bark shakes continuously. During the year, over 10,000 earthquakes are observed, but most of them are so weak that is not felt by the person and is fixed only by the instruments.

Earthquake power is measured in points - from 1 to 12. Powerful 12-point earthquakes are rare and are catastrophic. With such earthquakes, deformations occur in the earth's crust, cracks, shifts, discharges, collaps in the mountains and dips on the plains are formed. If they occur in densely populated places, there are big destruction and numerous human sacrifices. The largest earthquakes In history are Messinskoye (1908), Tokyo (1923), Tashkent (1966), Chilean (1976) and Spitakskoe (1988). Dozens killed in each of these earthquakes, hundreds and thousands of people, and cities were destroyed almost to the ground.

Often the Gip Center is under the ocean. Then the destructive ocean wave arises - tsunami.

Simultaneously with internal, tectonic processes on Earth, external processes apply. Unlike internal, covering the entire thickness of the lithosphere, they act only on the surface of the Earth. The depth of their penetration into the earth's bark does not exceed several meters and only in the caves - up to several hundred meters. The source of the origin of the forces causing external processes is thermal solar energy.

External processes are very diverse. These include weathered rocks, wind, water and glaciers.

Weathering.It is divided into physical, chemical and organic.

Physical weathered- This is a mechanical fragmentation, grinding rocks.

It occurs with a sharp change in temperature. When the breed is heated, it is expanding when cooling is compressed. Since the coefficient of expansion of different minerals included in the breed, noodynaks, the process of its destruction is enhanced. At first, the breed decays on large boulders, which are crushed over time. Accelerated breed destruction promotes water, which, penetrating into cracks, freezes in them, expands and breaks the breed into separate parts. The most active physical weathering acts where there is a sharp change of temperature, and solid magmatic rocks are cut to the surface - granite, basalt, shenietites, etc.

Chemical weathered- This is a chemical impact on rock rocks of various aqueous solutions.

At the same time, in contrast to physical weathelation, a variety of chemical reactionsAs a result, the change in the chemical composition and, possibly, the formation of new rocks. There is a chemical weathering everywhere, but especially intensively proceeds in precious breeds - limestones, gypsum, dolomites.

Organic weathered It is a process of destruction of rocks by alive organisms - plants, animals and bacteria.

Lichens, for example, attending the rocks, draw their surface to the extracted acid. Plant roots also distinguish acid, and in addition, the root system acts mechanically, as if breaking down the breed. Rain Wormspassing through yourself inorganic substancesTransform the breed and improve access to it water and air.

Weathered and climate.All types of weathered proceed at the same time, but act with different intensity. It depends not only on the categories, but mainly from the climate.

IN polar countries Frosty weathering is most actively manifest, in moderate - chemical, in tropical deserts - mechanical, in wet tropics - chemical.

Wind work.The wind is able to destroy rock rocks, to transfer and lay them solid particles. The stronger the wind and the more often it blows, the greater the work it is capable of producing. Where rocky outcrops go to the surface of the earth, the wind bombards them with grains, gradually washing and destroying even the richery rocks. Less stable breeds are destroyed faster, specific, eLOWY Forms Relief - Stone lace, eolic mushrooms, pillars, towers.

In the sandy deserts and on the shores of the seas and large lakes, the wind creates specific form of relief - verakhans and dunes.

Barhana - These are the movable sandy hills of the sickle form. The implanted slope is always gently (5-10 °), and leveled - steep - to 35-40 ° (Fig. 27). The formation of vegans is associated with the braking of the wind flow, carrying sand, which is due to any obstacles - surface irregularities, stones, bushes, etc. The strength of the wind weakens, and the sand deposition begins. The constant the winds and the more sand, the faster the Barhalan is growing. The highest vehans - up to 120 m - found in the deserts of the Arabian Peninsula.

Fig. 27.Barhana structure (the arrow shows the direction of the wind)

Moving verakans in the direction of wind. The wind drives grazing slope. Having achieved the ridge, the wind stream swirls, the speed decreases, the sands fall out and roll along the steep lean slope. This causes the movement of all the vegan at speeds up to 50-60 m per year. Moving, vegans can fall asleep oases and even whole villages.

On sandy beaches waving sands form dunes.They stretch along the shore in the form of huge sandy groin or hills up to 100 m and more. Unlike the velchanov, they do not have a permanent form, but can also move in the direction from the beach into the depths of sushi. In order to stop the traffic of the dunes, planting wood-shrub plants are planted, first of all pines.

Work of snow and ice.Snow, especially in the mountains, performs considerable work. In the slopes of the mountains accumulate huge masses of snow. From time to time they break off from the slopes, forming snow avalanches. Such avalanches, moving at a huge speed, capture the wreckage of rocks and carries down, despicable everything in their path. For the formidable danger that snow avalanches are carrying, they are called "white death."

The solid material that remains after melting of the snow, forms huge stony bugs, brave and filling intermediate depressions.

Even more work performed glaciers.They occupy tremendous squares on Earth - more than 16 million km 2, which is 11% of the Sushi area.

There are mainland glaciers, or coating, and mountain. Mainland icehuge areas in Antarctica, Greenland, on many polar islands. The thickness of the ice of continental glaciers is not the same. For example, in Antarctica it reaches 4000 m. Under the action of tremendous gravity, the ice slides into the sea, it is riveted, and formed icebergs - Ice floating mountains.

W. mountain glaciersthere are two parts - food areas or snow accumulation and melting. Snow accumulates in the mountains above snow line.The height of this line in different latitudes is not the same: the closer to the equator, the higher the snow line. In Greenland, for example, it lies at an altitude of 500-600 m, and on the slopes of the chimborace volcano in Andes - 4800 m.

Above the snow line the snow accumulates, compacted and gradually turns into ice. The ice has plastic properties and under the pressure of the overlying masses begins to slide down the slope down. Depending on the mass of the glacier, its saturation of water and the slope of the slope, the speed of movement ranges from 0.1 to 8 m per day.

Moving along the slopes of the mountains, the glaciers sweep the rods, smooth the protrusions of the rocks, expand and deepen the valleys. The chip material that the glacier captures with its movement, when melting (retreat) of the glacier, remains in place, forming a glacial sea. Moraine - These are piles of fragments of rocks, boulders, sand, clay left by the glacier. There are nineteen, side, side, surface, middle and finite distinguish.

Mountain valleys, for which a glacier ever passed, is easy to distinguish: in these valleys, the residues are always detected, and their shape resembles a trough. Such valleys are called roots.

Work of fluid.The flowable waters include temporary rainflows and tale snowy water, streams, rivers and underground water. The work of flowing waters, taking into account the Time Factor, Grand Cinema. It can be said that the entire appearance of the earth's surface to one way or another is created by fluid water. All fluids unites what they produce three types of work:

- destruction (erosion);

- product transfer (transit);

- ratio (accumulation).

As a result, a variety of irregularities are formed on the surface of the Earth - ravines, furrows on the slopes, cliffs, valleys of rivers, sandy and pebble islands, etc., as well as emptiness in the thicker rocks - caves.

Effect of gravity.All bodies are liquid, solid, gaseous, located on Earth, are attracted to it.

The force with which the body is attracted to the ground is called force of gravity.

Under the action of this force, all bodies tend to take the lowest position on the earth's surface. As a result, water flows in the rivers occur, the rainwater is seeping into the stroke of the earth's crust, snow avalanches are collapsed, glaciers move, down the slides of rocks are moving down the slopes. Gravity - prerequisite External processes. Otherwise, weathering products would remain at the site of their formation, covering as a cloak, underlying rocks.

As you already know, the earth consists of a variety of chemical elements - oxygen, nitrogen, silicon, iron, etc. connecting between themselves, the chemical elements form minerals.

Minerals.Most of the minerals consists of two or more chemical elements. Find out how many elements are contained in mineral, you can chemical formula. For example, Galite (saber) consists of sodium and chlorine and has a NCL formula; magnetite (magnetic iron bar) - of three iron molecules and two oxygen (F 3 O 2), etc. Some minerals are formed by one chemical element, for example: sulfur, gold, platinum, diamond, etc. Such minerals are called native.In nature, about 40 native elements are known, which account for 0.1% of the mass of the earth's crust.

Minerals can not only be solid, but also liquid (water, mercury, oil), and gaseous (hydrogen sulfide, carbon dioxide).

Most minerals have a crystalline structure. The form of the crystal for this mineral is always constant. For example, quartz crystals have a form of a prism, a galita - the shape of the cube, etc. If the cook salt is dissolved in water, and then crystallize, then the newly formed minerals will acquire a cubic form. Many minerals have the ability to grow. The sizes range them from microscopic to gigantic. For example, on the island of Madagascar, a beryl crystal was found with a length of 8 m and a diameter of 3 m. Its weight is almost 400 tons.

By education, all minerals are divided into several groups. Some of them (field spat, quartz, mica) are highlighted from magma with slow cooled at high depths; Other (sulfur) - with quick cooled of lava; Third (grenades, jasper, diamond) - at high temperatures and pressure at large depths; fourth (grenades, rubies, amethysts) are isolated from hot water solutions in underground veins; Fifth (gypsum, salt, brown Zheleznyak) are formed during chemical weathered.

In total, there are more than 2500 minerals in nature. For their definition and study, physical properties are of great importance to which gloss, color, color feature, i.e., the trace left by mineral, transparency, hardness, spheel, break, share. For example, the quartz form of crystals prismatic, glitter glass, no spheel, is a breakfast, hardness 7, the proportion of 2.65 g / cm 3, the features have no; Galite has a cubic crystal form, hardness 2.2, the proportion of 2.1 g / cm 3, glitter glass, white color, sprayion perfect, the taste of salted, etc.

Minerals are most well known and widespread 40-50, which are called breeding (field spat, quartz, Galit, etc.).

Rocks.These rocks are a cluster of one or more minerals. Marble, limestone, gypsum consist of one mineral, and granite, basalt - from several. In total, there are about 1000 rocks in nature. Depending on the origin - genesis - rock rocks are divided into three main groups: igneous, sedimentary and metamorphic.

Magmatic breeds.Are formed when the magma is cooled; crystalline structure, do not have lamination; Do not contain remnants of animals and plants. Among the magmatic rocks distinguish the deep and emissions. Depthsformed in the depths of the earth's crust, where Magma is under great pressure and its cooling occurs very slowly. An example of a deep breed can serve as granite - the most common crystalline breed, consisting mainly of three minerals: quartz, field spat and mica. The color of granites depends on the color of the field spat. Most often they are gray or pink.

When the magma's outpouring is formed to the surface poland breed.They represent either a spectal mass resembling slag or vitreous, then they are called volcanic glass. In some cases, a small-crystalline breed of the type of basalt is formed.

Sedimentary rocks.Covered approximately 80% of the entire surface of the Earth. They are characterized by lamination and porosity. As a rule, sedimentary rocks are the result of accumulation in the seas and oceans of remnants of dead organisms or demolished particles of destroyed solid rocks. The accumulation process occurs unevenly, therefore layers of different power (thickness) are formed. In many sedimentary rocks, fossils or prints of animals and plants are found.

Depending on the place of formation, sedimentary rocks are divided into continental and sea. TO continental breedsthese include clays. Clay is a crushed product destruction of solid rocks. They consist of the smallest scaled particles, have the ability to absorb water. Clay plastic, waterproof. The color is spilled - from white to blue and even black. White clays are used for the production of porcelain.

Continental origin and widespread mountain breed - Les. This is a fine-grained, non-tinted breed of yellowish color, consisting of a mixture of quartz, clay particles, carbon dioxide and hydrates of iron oxide. Easily passes water.

Sea breedusually formed at the bottom of the oceans. These include some clays, sands, gravel.

Large group of sediment biogenic rocksformed from remnants of dead animals and plants. These include limestone, dolomites and some flammable minerals (peat, stone coal, combustible shale).

Especially widely in the earth's crust is common, consisting of carbon dioxide. In its fragments, it is easy to see the accumulations of small shells and even skeletons of small animals. Limestone color is different, more often gray.

Chalk is also formed from the smallest shells - the inhabitants of the sea. The huge reserves of this rock are located in the Belgorod region, where in the steep banks of the rivers you can see the outlets of the powerful layers of the chalk, highlighting its whiteness.

Limestones, in which there is an admixture of carbon dioxide, is called dolomites. Limestones are widely used in construction. Of these, it makes lime for plastering and cement. The best cement is made from Mergel.

In those seas where animals having flimsy shells used to live and grew algae containing flint, the rock was formed trepal. This is a light, dense, usually yellowish or light gray breed, which is a building material.

The sedimentaries also attribute rocks formed by water deposition(Gypsum, stone salt, potash salt, brown Zheleznyak, etc.).

Metamorphic breeds.This group of rocks was formed from sedimentary and magmatic breeds under the influence of high temperatures, pressure, as well as chemical changes. Thus, under the action of temperature and pressure on the clay, clay slates are formed, on sand - dense sandstones, and marble on limestones. Changes, i.e. metamorphosis, occur not only with sedimentary rocks, but also with magmatic. Under the influence of high temperatures and pressure, granite acquires a layered structure and a new breed is formed - GNEs.

High temperatures and pressure contribute to the recrystallization of rocks. From sandstones, a very durable crystal breed is formed - quartzite.

Science has been established that more than 2.5 billion years ago, the land was completely covered with the ocean. Then, under the influence of the inner forces, the raising of individual sections of the earth's crust began. The process of raising was accompanied by turbulent vulcanism, earthquakes, in the formation. Thus arose the first sites of sushi - the ancient cores of modern mainland. Academician V. A. Obruchev called them "Ancient Dark Earth."

As soon as the land rose over the ocean, external processes began to operate on the surface. Mountain breeds were destroyed, destruction products were demolished into the ocean and accumulated on its outskirts in the form of sedimentary rocks. The thickness of the precipitation reached several kilometers, and under its pressure the ocean bottom began to fade. Such giant deflection of the earth's crust under the oceans called geosynclinal.The formation of geosyncline in the history of the Earth is continuously from ancient times to the present. In the life of geosynclinal distinguish several stages:

– embryneal- deflection of the earth's crust and precipitation accumulation (Fig. 28, a);

– maturation- filling the deflection of precipitation when the thickness reaches 15-18 km and the radial and lateral pressure occurs;

– foldlessness- the formation of folded mountains under the pressure of the internal forces of the Earth (this process is accompanied by stormy volcanism and earthquakes) (Fig. 28, b);

– attense- Destruction of the armed mountains by external processes and education in their place of residual hilly plain (Fig. 28).

Fig. 28.The scheme of the structure of the plain, resulting from the destruction of the mountains (dotted line shows the reconstruction of the former mountainous country)

Since sedimentary rocks in the geosynclinal area are plastic, then as a result of the pressure occurred, they are crushed into the folds. Folded mountains are formed, such as Alps, Caucasus, Himalayas, Andes, etc.

Periods when in geosynclinal is active formation of folded mountains, called epochs of folding.There are several such epochs in the history of the land: Baikal, Caledonian, Gersinskaya, Mesozoic and Alpine.

The process of gas in geosynclinal can cover and amuseynosynclinal areas - the area of \u200b\u200bthe former, now destroyed mountains. Since the rocks are tough here, deprived of plasticity, they are not frozen into the folds, but are broken up with faults. Some sites rise, others are lowered - converted boulder and fold-bang mountains. For example, the folded mountains of the Pamir were formed in the Alpine Folding Epoch and the Altai and Sayan were reborn. Therefore, the age of the mountains is not determined by the time of their formation, but by age of a folded base, which is always indicated on tectonic maps.

Geosyncline, located at different stages of development, exist today. So, along the Asian coast of the Pacific Ocean, in the Mediterranean Sea there is a modern geosynclinal, which experiences the stage of ripening, and in the Caucasus, in the Andes and other folded mountains the process of the city is completed; The Kazakh Melkosopher is Pedpetner, a hilly plain, formed on the site of the destroyed mountains of Caledonian and Gerchinsky folding. The base of the ancient mountains is coming to the surface here - "Mountain witnesses", folded by durable magmatic and metamorphic rocks.

Extensive sections of the earth's crust with relatively small mobility and flat relief are called platforms.Based on platforms, in their foundation, there are durable magmatic and metamorphic rocks, indicating the processes of the property that once happened here. Typically, the foundation is covered with thick sediments. Sometimes the foundation breeds go to the surface, forming shields.The age of the platform corresponds to the age of the foundation. The ancient (Precambrian) platforms include Eastern European, Siberian, Brazilian and others.

Platforms are mostly plains. They experience predominantly oscillatory movements. However, in some cases, the formation of revived block mountains is possible. Thus, as a result of the emergence of great African faults, it took a raise and lowering of certain sections of an ancient African platform and a blocking mountains and highlands were formed East Africa, Mount-volcanoes of Kenya and Kilimanjaro.

Lithospheric plates and their movement.The doctrine of geosynclinal and platforms received a name in science "Fixism",because according to this theory, large bark blocks are fixed in one place. In the second half of the XX century. Many scientists supported mobilism theory,the basis of which lies an idea of \u200b\u200bthe horizontal movements of the lithosphere. According to this ORIA, the entire lithosphere is deep-faced faults reaching the upper mantle, divided into gigantic blocks - lithospheric plates. The boundaries between the plates can take place both by land and on the bottom of the oceans. In the oceans, these borders usually serve as the middle oceanic ridges. In these areas, a large number of faults are fixed - the rifts, according to which the substance of the upper mantle is poured into the bottom of the ocean, spreading along it. In those areas where the borders between the plates are often activated by the processes of the property - in the Himalayas, Andes, Cordillera, Alps, etc. The base of the plates is in the asthenosphere, and on its plastic substrate, lithospheric plates, like gigantic icebergam, are slowly moving in different directions (Fig. 29). The movement of the plates is fixed with the exact dimensions from the space. So, the African and Arabian coast of the Red Sea slowly removes each other, which allowed some scientists to call this sea "germs" of the future ocean. Space snapshots allow you to trace the direction of the deep fault of the earth's crust.

Fig. 29.Movement of lithospheric plates

The theory of mobilism convincingly explains the formation of mountains, since for their occurrence it is necessary not only radial, but also lateral pressure. Where two plates face, one of them is immersed under the other, and "torosa" is formed along the collision border, i.e. the mountains. This process is accompanied by earthquakes and volcanism.

Relief - This is a combination of irregularities of the earth's surface, differing in height above sea level, origin, etc.

These irregularities give the unique appearance of our planet. The formation of relief is influenced both internal, tectonic and external forces. Thanks to the tectonic processes, there are mainly large irregularities of the surface - mountains, highlands, etc., and the external forces are aimed at their destruction and the creation of smaller form of relief - river valleys, ravines, veragans, etc.

All the form of relief is divided into concave (depressions, valleys of rivers, ravines, beams, etc.), convex (hills, mountain ranges, volcanic cones, etc.), just horizontal and inclined surfaces. Their size may be the most diverse - from several tens of centimeters to many hundreds and even thousand kilometers.

Depending on the scale, the planetary, macro, meso and microfores are distinguished.

Planetary include protrusions of the continents and the depression of the oceans. The continents and oceans are often antipodes. So, Antarctica lies against the Arctic Ocean, North America - against Indian, Australia - against the Atlantic and only South America - against Southeast Asia.

The depths of oceanic wpadin fluctuate in large limits. The average depth is 3800 m, and the maximum, marked in the Mariana Wpads of the Pacific Ocean - 11 022 m. The highest point of sushi - Mount Everest (Jomolungma) reaches 8848 m. Thus, the altitude amplitude reaches almost 20 km.

The prevailing depths in the ocean - from 3,000 to 6000 m, and heights on land - less than 1000 m. High mountains and deep-water depressions occupy only a fraction of the percentage of the surface of the Earth.

The average height of the continents and their parts above the ocean level is also not the same: North America - 700 m, Africa - 640, South America - 580, Australia - 350, Antarctica - 2300, Eurasia - 635 m, and the height of Asia is 950 m, and Europe - all 320 m. The average sushi height is 875 m.

Ocean bottom relief.At the bottom of the ocean, as well as on land, there are a variety of relief forms - mountains, plains, depressions, gutters, etc. They usually have a softer outline than similar shapes of land relief, as external processes flow here more calmly.

In the terrain of the ocean bottom allocate:

– mainland shallowor shelf (regiment), -the shallow part to the depth of 200 m, the width of which in some cases reaches many hundred kilometers;

– mainland slope - Pretty steep ledge to a depth of 2500 m;

– ocean bed,which occupies most of the bottom with depths to 6000 m.

The greatest depths are marked in guttersor oceanic depuseswhere they exceed the mark of 6000 m. The gutter is usually stretched along the continents in the outskirts of the ocean.

In the central parts of the oceans there are median oceanic ridges (rifts): South Atlantic, Australian, Antarctic, etc.

Relief sushi.The main elements of the Relief of Sushi are mountains and plains. They form a macro-relief of the Earth.

Goro.referred to the elevation having a vertex point, the slopes, the plantar line, rising above the terrain above 200 m; The elevation of the height of up to 200 meters is called hill.Linearly elongated relief forms having a ridge and slopes - this mountain ridges.Ranges are divided located between them mountain valleys.Connecting between themselves, the mountain ranges form mountain chains.The combination of ridges, chains and valleys are called mountain node,or mountain countryand in everyday life - mountains.For example, Altai Mountains, Ural Mountains, etc.

Extensive sections of the earth's surface consisting of mountain ranges, valleys and high plains are called highlands.For example, Iranian Highlands, Armenian Highlands, etc.

By the origin of the mountain is tectonic, volcanic and erosion.

Tectonic mountainsthey are formed as a result of the movements of the earth's crust, they consist of one or many folds raised at a considerable height. All the highest mountains of the world - Himalayas, Hindukush, Pamir, Cordillera, etc. - folded. They are characterized by pointed peaks, narrow valleys (cramped), elongated ridges.

Blindand mountain Mountainsthey are formed as a result of raising and lowering blocks (blocks) of the earth's crust on fault planes. For the relief of these mountains, flat peaks and watersheds are characterized, wide, flat bottom, valleys. This, for example, Ural Mountains, Appalachi, Altai, etc.

Volcanic mountainsthey are formed as a result of the accumulation of products of volcanic activity.

On the surface of the earth is quite widespread erosion mountainswhich are formed as a result of the dismemberment of high plains by external forces, primarily flowing water.

At the height of the mountain is divided into low (up to 1000 m), medium-high (from 1000 to 2000 m), high (from 2000 to 5000 m) and the highest (above 5 km).

The height of the mountains is easy to determine the physical card. It can also determine that most of the mountains refers to medium-altitude and high. Above 7000 m, few vertices rise, and all of them are in Asia. The height of more than 8000 m has only 12 mountain peaks located in the Karakorum and Himalayas mountains. The highest point of the planet is the mountain, or, more precisely, the mountain node, Everest (Jomolungma) - 8848 m.

Most of the surface of the sushi occupy the plain spaces. Plains - These are plots of terrestrial surface having a flat or weak-hearty relief. Most often plain slightly inclined.

By the nature of the surface of the plain divide on flat, wavyand hillybut on extensive plains, such as Turansk or West Siberian, can be found areas with various form of surface relief.

Depending on the height above the sea level, the plains are divided into lowlands(up to 200 m) sublime(up to 500 m) and high (Plateau)(Over 500 m). Elevated and high plains are always strongly dissected by aquatic streams and have a hilly relief, low-albele are often flat. Some plains are located below sea level. So, the Caspian lowland has a height of 28 m. Often on the plains there are closed basins of great depths. For example, Wpadina Karagis has a mark of 132 m, and Wpadina of the Dead Sea is 400 m.

Sublime plains limited by steep ledgers separating them from the surrounding area are called plateau.Such are the Plateau Ustyurt, Pouotner, etc.

Plateau. - Flat-host sections of the earth's surface, can have a significant height. So, for example, a plateau Tibet rises above 5000 m.

By origin, several types of plains are distinguished. Sustal sushi spaces occupy sea (primary) plains,formed as a result of marine regressions. This, for example, Turan, West Siberian, Great Chinese and a number of other plains. Almost all of them belong to the great plains of the planet. Most of them are lowland, relief flat or slightly hilly.

Plastic plains - These are flat sections of ancient platforms with almost horizontal sealing of sedimentary breeds. Such plains include, for example, Eastern European. Plains these mostly have hilly relief.

Small spaces in river valleys occupy alluvial (apparent) plains,formed as a result of alignment of the surface with river sediments - alluvia. This type includes the plains of Indo-Gangskaya, Mesopotamskaya, Labrador. These plains are low, flat, very fertile.

High above sea level. Plains are raised - lava Pokrov(Medium-Russian Plateau, Ethiopian and Iranian Highlands, Dean Plateau). Some plains, for example, the Kazakh small minister, were formed as a result of the destruction of the mountains. They are called erosion.These plains are always sublime and hilly. These hills are stacked by durable crystalline rocks and represent the remains of the former mountains here, their "roots".

The soil- This is the upper fertile layer of lithosphere, which has a number of properties inherent in lively and inanimate nature.

The formation and existence of this natural body cannot be submitted without living beings. Surface layers of rocks are only the source substrate from which under the influence of plants, microorganisms and animals are formed different kinds soil.

The founder of soil science Russian scientist V. V. Dokuchaev showed that

the soil - This is an independent natural body formed on the surface of rocks under the influence of living organisms, climate, water, relief, as well as a person.

This natural education was created by millennia. The process of soil formation begins with settlement on bare rocks, microorganisms. Feeding with carbon dioxide, nitrogen and water vapor from the atmosphere, using mineral salts of rock, microorganisms are isolated as a result of organic acids. These substances gradually change the chemical composition of rocks, make them less durable and ultimately tear off the surface layer. Then lichens are in such a breed. Unpretentious to water and nutrients, they continue the process of destruction, at the same time enriching the breed organic substances. As a result of the activities of microorganisms and lichen rocks, the rock gradually turns into a substrate suitable for settling by plants and animals. The final transformation of the initial breed into the soil occurs due to the vital activity of these organisms.

Plants absorbing carbon dioxide from the atmosphere, and from soil water and mineral substances, create organic compounds. Fixing, plants enrich the soil with these compounds. Animals feed on plants and their remnants. Products of their vital activity are excrement, and after death and their corpses also fall into the soil. The whole mass of dead organic matter, accumulated as a result of the vital activity of plants and animals, serves as a feed base and habitat for microorganisms and mushrooms. They destruct organic matter, mineralize them. As a result of the activities of microorganisms, complex organic substances are formed, which constitute the humus of the soil.

Humus soil - This is a mixture of sustainable organic compounds formed during the decomposition of plant and animal residues and products of their livelihoods with the participation of microorganisms.

The decay of primary minerals and the formation of clay secondary minerals occur in the soil. Thus, in the soil flows the substances.

Moisture intensity - This is the ability of the soil to hold water.

The soil in which there is a lot of sand, poorly holds water and has low moisture intensity. Clay soil, on the contrary, keeps a lot of water and has a high moisture intensity. In case of abundant precipitation, water fills all the pores in such a soil, preventing air passage to air. Loose, merciful soils are better kept moisture than dense.

Moisture permeability - This is the ability of the soil to pass water.

The soil is permeated with the smallest pores - capillaries. In terms of capillaries, water can move not only down, but also in all directions, including from the bottom up. The higher the patristicity of the soil, the higher its moisture permeability, the faster the water penetrates into the soil and rises from deeper layers up. Water "sticks" to the walls of the capillaries and as if crawling up. The thinner of the capillaries, the higher the water rises. At the exit of capillaries to the surface, water evaporates. Sand soils have high moisture permeability, and clay - low. If, after rain or watering on the surface of the soil, the crust (with many capillaries) was formed, the water evaporates very quickly. When looming the soil capillaries are destroyed, it reduces the evaporation of water. No wonder the soil is called dry irrigation.

Soils may have a different structure, i.e. consisting of various ones and magnitude of lumps, in which soil particles are glued. At the best soils, such as chernozem, the structure is small and grainy. By chemical composition of the soil can be rich or poor nutritional elements. The amount of humus is the indicator of the fertility of the soil, since it has all the basic elements of plant nutrition. For example, chernozem soils contain up to 30% humus. Soils can be acidic, neutral and alkaline. Neutral soils are most favorable for plants. To reduce acidity, they are encountered, and gypsum is made to reduce alkalinity into the soil.

Mechanical composition of soils.The mechanical composition of the soil is divided into clay, sandy, lug-and-and sandy.

Clay soilsthey have high moisture intensity and best are provided with nutrition elements.

Sand soilsmalvalamics, well-rotated, but poor humus.

Suglinist - The most favorable in their physical properties for agriculture, with medium moisture intensity and moisture permeability, well provided with humus.

Supply - Structural soils, poor humus, good water and breathable. To use such soils, it is necessary to improve their composition, make fertilizers.

Types of soil.In our country, the following soil types are most common: tundra, podzolic, dend-podzolic, chernozem, brown, serous, red, and yellow-tempered.

Tundra soilslocated in the extreme north in the zone of permafrost. They were moistened and extremely poor humus.

Podzolic soilscommon in taiga under coniferous, and dernovo-podzolic - Under coniferous-decide forests. Wide forests grow on gray forest soils. All these soils contain enough humus, are well structured.

In the forest-steppe and steppe zones are located chernozem soils.They were formed under steppe and herbal vegetation, rich in humus. The humus gives the soil black. They have a solid structure and have high fertility.

Chestnut soilsthey are south, they are formed at dry conditions. They are characterized by lack of moisture.

Serous soilscharacteristic for deserts and semi-deserts. They are rich in nutrients, but poor nitrogen, there is not enough water here.

Red 19and yellowemesthey are formed in subtropics in a wet and warm climate. They are well structured, enough moisture mixtures, but have a lower content of humus, so fertilizers make fertility to increase fertility.

To increase soil fertility, it is necessary to regulate in them not only the nutrient content, but also the presence of moisture and aeration. An arable layer of the soil should always be loose to ensure air access to the roots of plants.