As a result of mastering the content of Chapter 14, the student must:
know
The concepts of “geographical envelope”, “natural-territorial complex”, patterns and features of the geographical envelope;
be able to
- distinguish PTC by level, explain the cause-and-effect relationships between all components of PTC;
- adapt knowledge and skills for their use in professional activities;
own
Skill in searching and selecting information when using information and communication tools.
The concept of geographical envelope
Geographical envelope- a complex natural-anthropogenic system of our planet. This is a holistic, continuous outer shell of the Earth, within which all geospheres touch and interact: lithosphere, atmosphere, hydrosphere and biosphere (Fig. 14.1).
The idea of this shell was first introduced into science at the beginning of the 20th century, but modern concept the geographical envelope was developed only in the 1930s. Academician L. A. Grigoriev.
There are three stages in the development of the geographical envelope. At the first stage, the earth's crust, continents and oceans were formed. Chemotrophic bacteria arose, and subsequently photosynthetic organisms. The second stage (Paleozoic, Mesozoic, Cenozoic) is significant for the formation of the ozone screen, the formation of the hydrosphere and atmosphere in its modern form. There was a qualitative and quantitative leap in the development of living matter, and soils were formed. The third stage is associated with the emergence of Homo sapiens and continues to the present day. The main difference between this stage is the human impact on the natural environment.
The current stage of development of the geographical envelope is characterized by the formation of natural-anthropogenic systems.
Rice. 14.1.
Until now, the issue of the boundaries of the geographical envelope (GE) is debatable. The upper limit is considered to be ozone layer, and the bottom - the base of the weathering crust. Many scientists are of the opinion that the boundaries of the geographical envelope can be considered the boundaries of the distribution of living matter in it. It includes the lower layer of the atmosphere, the hydrosphere, top part lithosphere, living organisms and the layer within which human economic activity occurs.
All the earth's shells in the near-surface part of the Earth mutually penetrate each other, touching and interacting. So, as a result of long-term interaction, a continuous shell was formed - geographical envelope.
The geographic envelope has the following features.
- 1. Substance exists in three states of aggregation.
- 2. They enter the geographic shell different kinds energy, due to which diverse processes occur. Part of the energy is conserved in the bowels of the Earth (combustible useful
fossils), some of them go into outer space. The radiant energy of the Sun is converted into thermal energy.
- 3. The substance in the geographic envelope has a wide range of physical characteristics and chemical composition.
- 4. The geographical envelope was the place of origin and spread of life.
- 5. Geographical envelope - the place of human activity.
The geographic envelope is a natural complex on a planetary scale, its integrity is determined by the continuous exchange of matter and energy between its in different parts. The structural parts of the geographical shell are components and natural complexes.
The components of the geographic envelope are: rocks, water and air, plants and animals, and a special formation - soil. They participate in the formation of both natural and anthropogenic landscapes.
The components vary according to physical condition, By chemical composition. There are also differences in the level of organization: living (plants and animals), non-living (rocks, air, water), bio-inert (soil). Based on the degree of activity, components are also divided into stable (rocks and soil), mobile (water and air), and active (living organisms).
The most complex structure in the geographic shell is distinguished by thin layers of direct contact and active interaction of parts of the lithosphere, atmosphere and hydrosphere. These include, firstly, the land surface (the upper layer of the lithosphere), the ground layer of the atmosphere, surface and The groundwater. Secondly, the upper layer of the World Ocean, thirdly, the ocean floor. V.I. Vernadsky called these contact zones “films of life” because it is here that the highest concentration of living matter is observed.
The geographic envelope has regularities: integrity, circulation of matter, rhythm, zonality.
Let us consider the essence of these patterns.
1. Integrity means the unity of the geographical shell, which is determined by the circulation of matter and energy between the components. The geographic envelope develops as a single whole.
Integrity means that all components of the geographic shell are interconnected, and a change in one component invariably entails a change in all the others. Human economic activity also affects the components of the geographic envelope. Therefore, when human intervention in nature, it is necessary to take into account such a property of the geographical shell as integrity.
- 2. The circulation of matter in nature is another important regularity of the geographical shell, thanks to which energy is exchanged in it. There is a water cycle (large and small), a cycle of rocks, nitrogen, circulation of the atmosphere and ocean currents. (The process of the water cycle in the geographic envelope is discussed in Chapter 4.) However, there is also a water cycle in the ocean. Sea currents form ocean circulation rings. Major currents occur between equatorial regions and forties latitudes. Under the influence of the Coriolis force, currents are deflected to the right, moving clockwise in the Northern Hemisphere. A similar picture is emerging in the Pacific Ocean. The cycle and circulation of water in the ocean are supported by compensatory currents. The movements of water in the ocean reflect the circulation of the atmosphere, in which, therefore, circulation of matter (air) is also observed. The circulation of the atmosphere in equatorial and temperate latitudes was discussed in more detail in Chapter 5. We should not forget about the circulation of solid matter and rocks. Magma, arriving on the surface of the Earth, turns into effusive, i.e. igneous rocks. Under the influence of external forces, they change, are destroyed, transported by water, wind or ice to other places and deposited in the form of sediments. Gradually, during the process of metamorphism, they turn into metamorphic rocks, and later they can again turn into igneous, etc.
- 3. Rhythm is another regularity of civil engineering, which implies the repeatability of phenomena over time. There are daily, annual, intra-century rhythms, etc.
The daily rhythm in nature is determined by the axial rotation of the Earth, therefore, by the change of day and night, when the light regime changes (the illuminated and unlit part of the day). Non-living and Live nature(daily variation of air temperature, absolute and relative humidity, photosynthesis processes, vital activity of plants and animals).
The annual rhythm in the geographic envelope is determined by the annual (orbital) movement of the Earth and the change of seasons. In temperate latitudes, the seasonal rhythm is pronounced. It is affected by air and water temperatures, atmospheric circulation, and animal migration.
There are also intrasecular rhythms. The most noticeable for the geographic envelope are 11-year rhythms, which are associated with periodic changes in solar activity. 30-35-year cycles are also noted; they are considered as three-fold 11-year cycles. The eras of mountain building, according to a common point of view, manifested themselves as a consequence of the rhythm of the 26,000-year cycle associated with a change in the angle of inclination of the earth's axis to the orbital plane.
An important pattern of the geographical envelope can be considered zoning - a natural change in natural components and natural complexes from the equator to the poles. Geographic zoning as a law was established by V.V. Dokuchaev.
Zoning is explained by the fact that the Earth occupies different positions in relation to the Sun throughout the year, therefore, it is illuminated and heated differently. Angle of incidence sun rays on the earth's surface is different, which is due to the shape of the Earth. At the same time, a distinction is made between component (for example, temperature, wind, climate) and complex (geographical) geographic zonation.
Along with zonality, the main features of the nature of a particular region are determined by azonal factors (azonality). This concept means the distribution of any geographical feature or phenomena out of connection with the zonal features of the territory, in “violation” of zonality. The most a shining example currents, for example, cold ones, can serve. Passing along the coast, they contribute to a decrease in air temperature, a decrease in the amount of precipitation and, as a result, the formation of coastal deserts. In mountainous countries, altitudinal zonation is observed - a natural change in natural components and natural complexes from the foothills of the mountains to the peaks, which is mainly determined by a decrease in air temperature with height and a change in the amount of precipitation. The concept of “vertical zoning” is somewhat broader, since it implies a change in natural complexes not only with height, but also with depth (a decrease in the amount of heat and sunlight).
The largest complex zonal divisions of the geographic envelope are called geographic zones. They encircle the globe in the latitudinal direction. Their isolation occurs due to approximately the same amount of solar radiation. Therefore, each belt differs in radiation balance, atmospheric circulation, rate of energy and matter circulation, rhythms in nature, etc. The following belts are distinguished: equatorial, two subequatorial, two tropical, two subtropical, two temperate, subarctic and subantarctic, arctic and antarctic.
Natural zones are distinguished within geographical zones. The geographic envelope consists of natural complexes of different ranks and sizes.
Geographical envelope- in Russian geographical science, this is understood as a holistic and continuous shell of the Earth, where its components: the upper part of the lithosphere (the earth’s crust), the lower part of the atmosphere (troposphere, stratosphere, hydrosphere and biosphere) - as well as the anthroposphere penetrate each other and are in close interaction. There is a continuous exchange of matter and energy between them.
The upper boundary of the geographic envelope is drawn in the atmosphere at an altitude of 25-30 km, the lower - within the lithosphere at a depth of several hundred meters, and sometimes up to 4-5 km or along the ocean floor.
The geographical envelope consists of structural parts - components. These are rocks, water, air, plants, animals and soils. They differ in physical state (solid, liquid, gaseous), level of organization (non-living, living, bio-inert), chemical composition, activity (inert - rocks, soil, mobile - water, air, active - living matter).
The geographical envelope has vertical structure, consisting of separate spheres. The lower tier is composed of dense material of the lithosphere, and the upper ones are represented by lighter material of the hydrosphere and atmosphere. This structure is the result of differentiation of matter with the release of dense matter in the center of the Earth, and lighter matter along the periphery. The vertical differentiation of the geographical shell served as the basis for F.N. Milkov to identify the landscape sphere within it - a thin layer (up to 300 m), where contact and active interaction of the earth’s crust, atmosphere and hydrosphere occurs.
1.Earth's crust- This is the upper part of solid ground. It is separated from the mantle by a boundary with a sharp increase in seismic wave velocities - the Mohorovicic boundary (the lower boundary of the earth's crust). The thickness of the crust ranges from 6 km under the ocean to 30-50 km on the continents.
There are two types of crust - continental and oceanic . In the building continental crust There are three geological layers:
Sedimentary cover. Sedimentary rocks are formed on earth's surface and near it in relatively low temperatures and pressures resulting from the transformation of marine and continental sediments. Divided into: clastic rocks (breccias, conglomerates, sands, silts) - coarse products of predominantly mechanical destruction of parent rocks, usually inheriting the most stable mineral associations of the latter; clayey rocks- dispersed products of deep chemical transformation of silicate and aluminosilicate minerals of parent rocks, transformed into new mineral species; chemogenic, biochemogenic and organogenic rocks- products of direct precipitation from solutions (for example, salts), with the participation of organisms (for example, siliceous rocks), accumulation organic matter a (for example, coals) or waste products of organisms (for example, organogenic limestones).
Granite
Basaltic. (these are dark gray, black or greenish-black breeds)
Oceanic crust composed predominantly of basic rocks, plus sedimentary cover. The earth's crust is divided into lithospheric plates of different sizes, moving relative to each other. The kinematics of these movements is described by plate tectonics.
2. Troposphere(ancient Greek “turn”, “change” and “ball”) - the lower, most studied layer of the atmosphere, 8-10 km high in the polar regions, up to 10-12 km in temperate latitudes, 16-18 km at the equator km.
When rising in the troposphere, the temperature decreases by an average of 0.65 K (0.65 °C) every 100 m and reaches 180-220 K (-93 - -76 °C) in the upper part. This upper layer of the troposphere, in which the decrease in temperature with height stops, is called tropopause. The next layer of the atmosphere, located above the troposphere, is called the stratosphere.
More than 80% of all mass is concentrated in the troposphere atmospheric air, turbulence and convection are highly developed (the phenomenon of heat transfer in liquids or gases, or granular media by flows of matter). The predominant part of the water vapor is concentrated, clouds arise, atmospheric fronts form, cyclones and anticyclones develop, as well as other processes that determine weather and climate. The processes occurring in the troposphere are caused primarily by convection.
The part of the troposphere within which the formation of glaciers on the earth's surface is possible is called chionosphere.
3.Stratosphere(from Latin stratum - flooring, layer) - a layer of the atmosphere located at an altitude of 11 to 50 km. The air density in the stratosphere is tens and hundreds of times less than at sea level. It is in the stratosphere that the ozonosphere layer is located (“ozone layer”, which determines the upper limit of life in the biosphere. In the stratosphere, most of the short-wave part of ultraviolet radiation (180-200 nm) is retained and the energy of short waves is transformed. Under the influence of these rays, changes magnetic fields, molecules disintegrate, ionization occurs, new formation of gases and other chemical compounds. These processes can be observed in the form of northern lights, lightning and other glows.
4. Hydrosphere(from ancient Greek water and ball) is the water shell of the Earth occupying 3/4 of the planet. It forms a continuous water shell. The average depth of the ocean is 3800 m, the maximum ( Mariana Trench Pacific Ocean) - 11,022 meters. The total volume of water on the planet is about 1,532,000,000 cubic kilometers. The region of the biosphere in the hydrosphere is represented in its entire thickness, but the highest density of living matter occurs in the surface layers heated and illuminated by the sun's rays, as well as coastal zones.
IN general view The hydrosphere is divided into the World Ocean, continental waters and groundwater. Most of the water is concentrated in the ocean, much less in the continental river network and groundwater. There are also large reserves of water in the atmosphere, in the form of clouds and water vapor. Over 96% of the volume of the hydrosphere is made up of seas and oceans, about 2% is groundwater, about 2% is ice and snow, and about 0.02% is land surface water. Some of the water is in solid state in the form of glaciers, snow cover and in permafrost, representing the cryosphere.
Surface waters, occupying a relatively small share of the total mass of the hydrosphere, nevertheless play a vital role in the life of the terrestrial biosphere, being the main source of water supply, irrigation and water supply. Moreover, this part of the hydrosphere is in constant interaction with the atmosphere and the earth's crust.
The interaction of these waters and mutual transitions from one type of water to another constitute a complex water cycle on the globe. Life on Earth first originated in the hydrosphere. Only at the beginning of the Paleozoic era did the gradual migration of animals and plant organisms to land begin. The oceanic crust is composed of sedimentary and basalt layers.
5.Biosphere(from ancient Greek life and sphere, ball) - the shell of the Earth, populated by living organisms and transformed by them. The biosphere began to form no later than 3.8 billion years ago, when the first organisms began to emerge on our planet. It penetrates the entire hydrosphere, the upper part of the lithosphere and the lower part of the atmosphere, that is, it inhabits the ecosphere. The biosphere is the totality of all living organisms. It is home to more than 3,000,000 species of plants, animals, fungi and bacteria, as well as humans. The French natural scientist Jean Baptiste Lamarck first proposed the concept of the biosphere, without even introducing the term itself. The term "biosphere" was proposed by the Austrian geologist and paleontologist Eduard Suess.
A holistic doctrine of the biosphere was created by the biogeochemist and philosopher V.I. Vernadsky. For the first time, he assigned living organisms the role of the most important transformative force on planet Earth, taking into account their activities not only at the present time, but also in the past.
Boundaries of the biosphere:
· Upper limit in the atmosphere: 15-20 km. It is determined by the ozone layer, which blocks short-wave radiation. ultraviolet radiation, harmful to living organisms.
· Lower boundary in the lithosphere: 3.5-7.5 km. It is determined by the temperature of transition of water into steam and the temperature of denaturation of proteins, but generally the distribution of living organisms is limited to a depth of several meters.
· The boundary between the atmosphere and the lithosphere in the hydrosphere: 10-11 km. Determined by the bottom of the World Ocean, including bottom sediments.
Structure of the Biosphere:
1. Living matter - the entire set of bodies of living organisms inhabiting the Earth is physical and chemically united, regardless of their systematic affiliation. The mass of living matter is relatively small and is estimated at 2.4...3.6 10 12 t (dry weight) and constitutes less than one millionth of the entire biosphere (approx. 3 10 18 t), which, in turn, represents less than one thousandth the mass of the Earth. But it is “one of the most powerful geochemical forces on our planet,” because living organisms do more than just inhabit earth's crust, but transform the appearance of the Earth. Living organisms inhabit the earth's surface very unevenly. Their distribution depends on geographic latitude.
2. Nutrient- a substance created and processed by a living organism. During organic evolution, living organisms passed through their organs, tissues, cells, blood a thousand times most atmosphere, the entire volume of the world's oceans, a huge mass of minerals. This geological role of living matter can be imagined from deposits of coal, oil, carbonate rocks, etc.
3. Inert substance- products formed without the participation of living organisms.
4. Bioinert substance- a substance that is created simultaneously by living organisms and inert processes, representing dynamically equilibrium systems of both. These are soil, silt, weathering crust, etc. Organisms play a leading role in them.
5. A substance undergoing radioactive decay.
6. Scattered atoms, continuously created from all kinds of earthly matter under the influence of cosmic radiation.
7. Substance of cosmic origin.
Layers of the biosphere:
The entire layer of influence of life on inanimate nature is called megabiosphere, and together with artebiosphere- the space of humanoid expansion in near-Earth space - panbiosphere.
6. Anthroposphere (noosphere)(Greek intelligence And ball) - sphere of reason; the sphere of interaction between society and nature, within the boundaries of which intelligent human activity becomes the determining factor of development (this sphere is also designated by the terms “anthroposphere”, “biosphere”, “biotechnosphere”).
The noosphere is supposedly a new, highest stage of the evolution of the biosphere, the formation of which is associated with the development of society, which has a profound impact on natural processes.
[The emergence and evolution of the concept
The concept of “noosphere” was proposed by Sorbonne mathematics professor Edouard Leroy (1870-1954), who interpreted it as a “thinking” shell formed by human
The geographical envelope of the earth or landscape envelope, the sphere of interpenetration and interaction of the lithosphere, atmosphere, hydrosphere and biosphere. It is characterized by a complex composition and structure. The vertical thickness of the geographic shell is tens of kilometers. The integrity of the geographic envelope is determined by the continuous exchange of energy and mass between the land and the atmosphere, the World Ocean and organisms. Natural processes in the geographic shell are carried out due to the radiant energy of the Sun and the internal energy of the Earth. Within the geographical shell, humanity arose and is developing, drawing resources from the shell for its existence and influencing it.
The upper boundary of the geographic envelope should be drawn along the stratopause, since Before this point, the thermal effect of the earth's surface on atmospheric processes is felt. The boundary of the geographic envelope in the lithosphere is combined with the lower limit of the hypergenesis region. Sometimes the base of the stratisphere, the average depth of seismic or volcanic sources, the base of the earth's crust, and the level of zero annual temperature amplitudes are taken as the lower boundary of the geographic envelope. Thus, the geographic shell completely covers the hydrosphere, descending in the ocean 10-11 km below the Earth's surface, the upper zone of the earth's crust and the lower part of the atmosphere (25-30 km thick layer). The greatest thickness of the geographic shell is close to 40 km.
The qualitative differences between the geographic shell and other shells of the Earth are as follows. The geographic envelope is formed under the influence of both terrestrial and cosmic processes; it is exceptionally rich in various types of free energy; the substance is present in all states of aggregation; the degree of aggregation of the substance is extremely varied - from free elementary particles- from atoms, ions, molecules to chemical compounds and complex biological bodies; the concentration of heat coming from the Sun; the presence of human society.
The main material components of the geographical shell are the rocks that make up the earth's crust in form - relief), air masses, water accumulations, soil cover and biocenoses; In polar latitudes and high mountains, the role of ice accumulations is significant.
The main energy components are gravitational energy, internal heat of the Earth, radiant energy from the Sun and energy from cosmic rays. Despite the limited set of components, their combinations can be very diverse; this depends on the number of components included in the combination and on their internal variations, since each component is also a very complex natural complex and, most importantly, on the nature of their interaction and interconnections, i.e., on the geographical structure.
The geographical envelope has the following important features:
1) the integrity of the geographical shell, due to the continuous exchange of matter and energy between its component parts, since the interaction of all components connects them into a single material system, in which a change in even one link entails a concomitant change in all the others.
2) The presence of a circulation of substances and the energy associated with it, ensuring the repetition of the same processes and phenomena and their high overall efficiency with a limited volume of the initial substance participating in these processes. The complexity of the cycles is different: some of them are mechanical movements (atmospheric circulation, a system of sea surface currents), others are accompanied by a change in the state of aggregation of matter (the circulation of water on Earth), and thirdly, its chemical transformation also occurs (biological cycle). The gyres, however, are not closed, and the differences between their initial and final stages indicate the development of the system.
3) Rhythm, i.e. the repetition of various processes and phenomena over time. It is caused mainly by astronomical and geological reasons. There are daily rhythms (change of day and night), annual (change of seasons), intrasecular (for example, cycles of 25-50 years, observed in fluctuations in climate, glaciers, lake levels, river water flow, etc.), supersecular (for example , change every 1800-1900 years from the cool-humid climate phase to the dry and warm phase), geological (Caledonian, Hercynian, Alpine cycles of 200-240 million years each), etc. Rhythms, like cycles, are not closed: the state that was at the beginning of the rhythm does not repeat at the end of it.
4).Continuity of development of the geographical shell as some kind of integral system under the influence of the contradictory interaction of exogenous and endogenous forces. The consequences and features of this development are: a) territorial differentiation of the land surface, ocean and seabed into areas that differ in internal features and external appearance (landscapes, geocomplexes); determined by spatial changes in geographic structure; special forms of territorial differentiation - geographic zoning, b) polar asymmetry, i.e., significant differences in the nature of the geographical envelope in the Northern and Southern Hemispheres; manifested in the distribution of land and sea (the vast majority of land is in the Northern Hemisphere), climate, composition of flora and fauna, the nature of landscape zones, etc.; c) heterochrony or metachrony of the development of the geographical envelope, due to the spatial heterogeneity of the nature of the Earth, as a result of which at the same moment different territories are either in different phases of an equally directed evolutionary process, or differ from each other in the direction of development (examples: ancient glaciation in different areas The earth began and ended at the same time; in some geographical zones the climate becomes drier, in others at the same time it becomes wetter, etc.).
The geographical envelope is the subject of the study of physical geography.
The geographic envelope is the shell of the Earth, within which the lower layers of the atmosphere, the upper parts of the lithosphere, the entire hydrosphere and the biosphere mutually penetrate each other and are in close interaction (Fig. 1).
The idea of the geographic shell as the “outer sphere of the earth” was introduced by the Russian meteorologist and geographer P. I. Brounov (1852-1927) back in 1910, and the modern concept was developed by the famous geographer, academician of the USSR Academy of Sciences A. A. Grigoriev.
Troposphere, earth's crust, hydrosphere, biosphere - these are the structural parts geographic envelope, and the substance contained in them is its Components.
Rice. 1. Scheme of the structure of the geographical shell
Despite the significant differences in the structural parts of the geographical shell, they have one common, very significant feature - the continuous process of movement of matter. However, the rate of intracomponent movement of matter in different structural parts of the geographic envelope is not the same. Highest indicator velocities are noted in the troposphere. Even when there is no wind, there is no completely still surface air. Conventionally, the average speed of movement of matter in the troposphere can be taken as 500-700 cm/s.
In the hydrosphere, due to the higher density of water, the speed of movement of matter is lower, and here, unlike the troposphere, there is a general natural decrease in the speed of movement of water with depth. In general, the average speeds of water transfer in the World Ocean are (cm/s): on the surface - 1.38, at a depth of 100 m - 0.62, 200 m - 0.54, 500 m - 0.44, 1000 m - 0 .37, 2000 m - 0.30, 5000 m -0.25.
In the earth's crust, the process of matter transfer is so slow that it requires special studies. The speed of movement of matter in the earth's crust is measured in several centimeters or even millimeters per year. Thus, the rate of expansion of the mid-ocean ridge varies from 1 cm/year in the Arctic Ocean to 6 cm/year in the equatorial Pacific Ocean. The average rate of expansion of the oceanic crust is approximately 1.3 cm/year. The established vertical speed of modern tectonic movements on land is of the same order.
In all structural parts of the geographic shell, the intracomponent movement of matter occurs in two directions: horizontal and vertical. These two directions do not oppose each other, but represent different sides the same process.
There is an active and continuous exchange of matter and energy between the structural parts of the geographic shell (Fig. 2). For example, water enters the atmosphere as a result of evaporation from the surface of the ocean and land, solid particles enter air envelope during volcanic eruptions or with the help of wind. Air and water, penetrating through cracks and pores deep into rock formations, enter the lithosphere. Gases from the atmosphere are constantly entering reservoirs, as well as various solid particles, which are carried away by water flows. The upper layers of the atmosphere are heated from the Earth's surface. Plants absorb from the atmosphere carbon dioxide and release oxygen into it, which is necessary for breathing for all living beings. Living organisms die and form soils.
Rice. 2. Diagram of connections in the geographic shell system
The vertical boundaries of the geographic envelope are not clearly expressed, so scientists define them differently. A. A. Grigoriev, like most scientists, upper limit geographical envelope was carried out in the stratosphere at an altitude of 20-25 km, below the layer of maximum ozone concentration that blocks ultraviolet radiation from the Sun. Below this layer, air movements associated with the interaction of the atmosphere with land and ocean are observed; above, atmospheric movements of this nature disappear. The greatest controversy among scientists is the lower limit of the geographical envelope.
Most often it is carried out at the base of the earth's crust, i.e. at a depth of 8-10 km under the oceans and 40-70 km under the continents. Thus, the total thickness of the geographic envelope is about 30 km. Compared to the size of the Earth, it is a thin film.
About 40,000 kilometers. The geographic shells of the Earth are systems of the planet where all the components inside are interconnected and defined relative to each other. There are four types of shells - atmosphere, lithosphere, hydrosphere and biosphere. The aggregate states of substances in them are of all types - liquid, solid and gaseous.
Shells of the Earth: atmosphere
The atmosphere is the outer shell. It contains various gases:
- nitrogen - 78.08%;
- oxygen - 20.95%;
- argon - 0.93%;
- carbon dioxide - 0.03%.
In addition to them, ozone, helium, hydrogen, and inert gases are found, but their share in the total volume is no more than 0.01%. This shell of the Earth also includes dust and water vapor.
The atmosphere, in turn, is divided into 5 layers:
- troposphere - height from 8 to 12 km, characterized by the presence of water vapor, the formation of precipitation, and the movement of air masses;
- stratosphere - 8-55 km, contains the ozone layer, which absorbs UV radiation;
- mesosphere - 55-80 km, low air density compared to the lower troposphere;
- ionosphere - 80-1000 km, contains ionized oxygen atoms, free electrons and other charged gas molecules;
- the upper atmosphere (scattering sphere) is more than 1000 km, molecules move at enormous speeds and can penetrate into space.
The atmosphere supports life on the planet because it helps keep the Earth warm. It also prevents direct sunlight from penetrating. And its precipitation influenced the soil-forming process and climate formation.
Shells of the Earth: lithosphere
This hard shell composing the earth's crust. The globe consists of several concentric layers with different thicknesses and densities. They also have a heterogeneous composition. The average density of the Earth is 5.52 g/cm 3, and in the upper layers it is 2.7. This indicates that there are more than heavy substances than on the surface.
The upper lithospheric layers have a thickness of 60-120 km. They are dominated by igneous rocks - granite, gneiss, basalt. Most of them were subjected to destruction processes over millions of years, pressure, temperatures and turned into loose rocks - sand, clay, loess, etc.
Up to 1200 km there is the so-called sigmatic shell. Its main constituents are magnesium and silicon.
At depths of 1200-2900 km there is a shell called medium semi-metallic or ore. It mainly contains metals, in particular iron.
Below 2900 km is the central part of the Earth.
Hydrosphere
The composition of this shell of the Earth is represented by all the waters of the planet, be it oceans, seas, rivers, lakes, swamps, groundwater. The hydrosphere is located on the surface of the Earth and occupies 70% of the total area - 361 million km 2.
1375 million km 3 of water is concentrated in the ocean, 25 on the land surface and in glaciers, and 0.25 in lakes. According to Academician Vernadsky, large reserves of water are located deep in the earth’s crust.
On the land surface, water is involved in continuous water exchange. Evaporation occurs mainly from the surface of the ocean, where the water is salty. Due to the process of condensation in the atmosphere, the land is provided with fresh water.
Biosphere
The structure, composition and energy of this shell of the Earth are determined by the processes of activity of living organisms. Biosphere boundaries - the land surface, the soil layer, the lower atmosphere and the entire hydrosphere.
Plants distribute and accumulate solar energy in the form of various organic substances. Living organisms carry out the migration process chemical substances in soil, atmosphere, hydrosphere, sedimentary rocks. Thanks to animals, gas exchange and redox reactions occur in these shells. The atmosphere is also the result of the activity of living organisms.
The shell is represented by biogeocenoses, which are genetically homogeneous areas of the Earth with one type of vegetation cover and inhabiting animals. Biogeocenoses have their own soils, topography and microclimate.
All shells of the Earth are in close continuous interaction, which is expressed as the exchange of substances and energy. Research in the field of this interaction and the identification of common principles is important for understanding the soil-forming process. Geographical shells of the Earth - unique systems, characteristic only for our planet.
