About 40,000 kilometers. The geographic shells of the Earth are the systems of the planet, where all the components 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 found of all types - liquid, solid and gaseous.
Shells of the Earth: atmosphere
The atmosphere is the outer shell. It includes various gases:
- nitrogen - 78.08%;
- oxygen - 20.95%;
- argon - 0.93%;
- carbon dioxide - 0.03%.
In addition to them, there are ozone, helium, hydrogen, inert gases, but their share in the total volume is no more than 0.01%. This shell of the Earth also contains dust and water vapor.
The atmosphere, in turn, is divided into 5 layers:
- troposphere - an altitude of 8 to 12 km, characterized by the presence of water vapor, the formation of precipitation, the movement of air masses;
- stratosphere - 8-55 km, contains an ozone layer that absorbs UV radiation;
- mesosphere - 55-80 km, low air density compared to the lower troposphere;
- ionosphere - 80-1000 km, it includes ionized oxygen atoms, free electrons and other charged gas molecules;
- the upper atmosphere (sphere of scattering) - more than 1000 km, molecules move at great speeds and can penetrate into space.
The atmosphere supports life on the planet as it helps keep the earth warm. It also prevents direct sunlight from entering. And its precipitation influenced the soil-forming process and the formation of the climate.
Shells of the Earth: the lithosphere
It is a hard shell that composes the earth's crust. The globe consists of several concentric layers with different thicknesses and densities. They also have a heterogeneous composition. The average value of the density of the Earth is 5.52 g / cm 3, and in the upper layers - 2.7. This indicates that there are heavier substances inside the planet than on the surface.
The upper lithospheric layers are 60-120 km thick. They are dominated by igneous rocks - granite, gneiss, basalt. Over the course of millions of years, most of them underwent processes of destruction, pressure, temperature and turned into loose rocks - sand, clay, loess, etc.
The so-called sigmatic shell is located up to 1200 km. Its main constituents are magnesium and silicon.
At depths of 1200-2900 km, there is a shell, called the middle semi-metallic or ore. Basically, it contains metals, in particular iron.
The central part of the Earth is located below 2900 km.
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.
The ocean contains 1375 million km 3 of water, on the land surface and in glaciers - 25, in lakes - 0.25. According to Academician Vernadsky, large reserves of water are located in the thickness of the earth's crust.
On the land surface, waters are involved in continuous water exchange. Evaporation occurs primarily from the ocean surface, where the water is salty. Due to the condensation process in the atmosphere, the dry 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 - land surface, soil layer, lower atmosphere and the entire hydrosphere.
Plants distribute and store the energy of the Sun in the form of various organic substances. Living organisms carry out the migration process of chemicals in the soil, atmosphere, hydrosphere, sedimentary rocks. Thanks to the animals, gas exchange and redox reactions take place in these membranes. The atmosphere is also the result of the activity of living organisms.
The envelope is represented by biogeocenoses, which are genetically homogeneous areas of the Earth with one type of vegetation cover and inhabiting animals. Biogeocenoses have their characteristic soils, relief and microclimate.
All shells of the Earth are in close continuous interaction, which is expressed as an 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. The geographic shells of the Earth are unique systems that are characteristic only of our planet.
biosphere noosphere technogenesis
The most common object of study in geography is the geographic envelope. The term "geographic envelope" was proposed by the famous geographer A.A. Grigoriev in 1932
The geographic envelope is the largest natural complex on Earth, in which the lithosphere, hydrosphere, atmosphere and biosphere, intricately intertwining, interact with each other, penetrate each other, exchange matter and energy. Each component of the complex has its own chemical composition, differs in its inherent properties. Within the envelope, as it were, lying on the border of the planet and space, both cosmic and internal forces act. One of the most important properties of the geographic envelope is the presence of substances (primarily water) simultaneously in a liquid, solid and gaseous state. They can have their own organization of matter, laws of development, can be organic or inorganic.
The processes taking place in the geographic envelope are diverse, closely related to each other and can be easily disrupted. They are still insufficiently studied and their significance is extremely important for the preservation of the Earth and human survival. The geographic envelope is unique, first of all, in that they act in it, intertwining with each other, complementing each other or colliding as opposite, different forms of energy: part of the earthly, part of the cosmic. The abundance of energy gives rise to various processes - geological, biological, physical and chemical. We are talking about the fact that on the earth's surface there is a confrontation between external and internal forces. Moreover, some of them seek to establish a balance. For example: the force of gravity, with which both the leveling of the relief and the runoff of water from its lowering are associated. The ebbs and flows are associated with the gravitational forces of the Moon and the Sun. Among the internal sources of energy in the first place is the decay of radioactive substances, which is associated with the formation of mountains and the movement of lithospheric plates, earthquakes and volcanic eruptions, the activity of geysers, hot springs. All these processes are accompanied by dehydration and degassing of the subsoil, that is, the removal of water and gases to the earth's surface. A significant role is also played by the fact that the Earth, as a common magnet, forms a magnetic field, which affects not only the processes of attraction, but also the behavior of electric charges in the atmosphere. Cosmic energy reaches the surface of the Earth in the form of various radiations, of which the sun is dominant. A lot of it is received. Much of the solar energy is reflected back into space. In solar energy, two important processes are connected, which create a unique shell on the Earth. This is the water cycle and the development of life. The boundaries of the geographic envelope are not clearly defined and are drawn by different scientists in different ways, since the bases for its division are different. But more often than not, everyone draws the following boundaries.
Fig. 1
The geographic envelope includes a layer of the atmosphere in which the presence of dust, mainly of volcanic origin, water vapor is noted, and organisms can exist. The height of this layer reaches 25-30 km, i.e. the geographic envelope includes the troposphere and the lower stratosphere. In the lithosphere, only a part of the earth's crust belongs to the geographic shell, which extends from the Earth's surface to a depth of several hundred meters, sometimes up to 4-5 km. It is to this depth that the influence of the atmosphere and hydrosphere on the lithosphere is traced. The composition of the geographic envelope includes almost the entire hydrosphere, with the exception of an insignificant part of it, which is located at great depths. The largest part of the geographic shell - the biosphere - is one of the shells of the Earth, the composition, properties and processes of which are determined by the activity of living organisms. That is, the selection of the boundaries of the biosphere is based on the activity of living organisms, and the basis of the geographic envelope is the presence of the interaction of the main parts (spheres). Therefore, the main parameters of the biosphere and geosphere may not coincide. There is no consensus regarding the relationship between the biosphere and the geographic envelope of the Earth. If we take the presence or absence of bacteria as a basis, then the habitat of the latter goes beyond the boundaries of the geographical envelope, since bacterial spores are found much higher than the troposphere, and bacteria are found in the oil-bearing layers of the lithosphere at depths of up to several kilometers. Within the land of the geographic envelope, individual scientists distinguish the landscape sphere. It is a thin layer (from 5-10 m in the tundra, up to 100-150 m in the tropics), including the upper part of the weathering crust, soil, vegetation, fauna, surface air, surface and ground waters.
The shell of the Earth, within which the lower layers of the atmosphere, the upper parts of the lithosphere, the entire hydrosphere and biosphere mutually penetrate and interact, is called geographic envelope(earth shell) All components of the geographic shell interact with each other.
The geographic envelope has no sharp boundaries. Many scientists believe that its thickness is 55 km on average. The geographic envelope is sometimes called the natural environment or simply nature.
Geographic envelope properties.
Only in the geographic envelope are substances in solid, liquid and gaseous state, which is of great importance for all processes occurring in the geographic envelope, and above all for the emergence of life. Only here, at the solid surface of the Earth, first life arose, and then man and human society appeared, for the existence and development of which there are all the conditions: air, water, rocks and minerals, solar heat and light, soil, vegetation, bacterial and animal world ...
All processes in the geographic envelope occur under the influence of solar energy and, to a lesser extent, internal terrestrial energy sources. Thus, geographic envelope properties : integrity, rhythm, zoning .
Integrity of GO manifests itself in the fact that a change in one component of nature inevitably causes a change in all the others. These changes can evenly cover the entire geographic envelope and are manifested in some of its separate parts, affecting other parts.
Rhythm natural phenomena consists in the recurrence of similar phenomena in time. Examples of rhythm: daily and annual periods of the Earth's rotation; long periods of mountain building and climate change on Earth; periods of solar activity change. The study of rhythms is important for forecasting processes and phenomena occurring in the geographic envelope.
Zoning - a regular change in all components of GO from the equator to the poles. It is caused by the rotation of the spherical Earth with a certain tilt of the axis of rotation around the Sun. Depending on the geographic latitude, solar radiation is distributed zonally and causes a change in climates, soils, vegetation and other components of the geographic envelope. The world law of the zoning of the geographic envelope is manifested in its division into geographic zones and natural zones. On its basis, physical and geographical zoning of the Earth and its individual sections is carried out.
Simultaneously with the zonal ones, and azonal factors associated with the internal energy of the Earth (relief, height, configuration of continents). They violate the zonal distribution of GO components. Anywhere in the world, zonal and zonal factors act simultaneously.
The cycle of substances and energy
The circulation of substances and energy is the most important mechanism of natural processes in the geographic envelope. There are various cycles of matter and energy: air cycles in the atmosphere, the earth's crust, water cycles, etc.
For the geographic envelope, it is of great importance The water cycle, which is carried out due to the movement of air masses. There can be no life without water.
A huge role in the life of the geographic envelope belongs biological circulation. In green plants, as you know, in the light of carbon dioxide and water organic substances are formed, which serve as food for animals. Animals and plants after death are decomposed by bacteria and fungi to mineral substances, which are then reabsorbed by green plants.
The leading role in all cycles belongs to the circulation of air in the troposphere, which includes the entire system of winds and vertical air movement. The movement of air in the troposphere draws into the global cycle and the hydrosphere, forming the world water cycle.
Each subsequent cycle is different from the previous ones. It does not form a vicious circle. Plants, for example, take nutrients from the soil, and when they die off, they give them much more, since the organic mass of plants is created mainly due to carbon dioxide in the atmosphere, and not due to substances coming from the soil.
The role of living organisms in the formation of nature.
Life makes our planet unique. Life processes consist of three main stages: creation of primary production as a result of photosynthesis of organic matter; transformation of primary (plant) products into secondary (animal) products; destruction of primary and secondary biological products by bacteria, fungi. Life is impossible without these processes. Living organisms include: plants, animals, bacteria and fungi. Each group (kingdom) of living organisms plays a specific role in the development of nature.
Under the influence of living organisms, there is more oxygen in the air and a decrease in the content of carbon dioxide. Green plants are the main source of atmospheric oxygen. The composition of the World Ocean became another. Rocks of organic origin appeared in the lithosphere. Deposits of coal and oil, most limestone deposits are the result of the activity of living organisms.
As a result of mastering the content of chapter 14, the student must:
know
The concepts of "geographic envelope", "natural-territorial complex", patterns and features of the geographic envelope;
be able to
- to distinguish the PTC by level, to explain the causal relationships between all the components of the PTC;
- to adapt knowledge and skills for their use in professional activities;
own
The skill of searching and selecting information when using information and communication tools.
The concept of the geographic envelope
The geographic envelope is a complex natural-anthropogenic system of our planet. This is an integral continuous outer shell of the Earth, within which all geospheres touch and interact: lithosphere, atmosphere, hydrosphere and biosphere (Fig. 14.1).
For the first time, the concept of this shell was introduced into science at the beginning of the 20th century, but the modern concept of the geographical shell was developed only in the 1930s. Academician L.A. Grigoriev.
There are three stages in the development of the geographic 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 remarkable for the formation of the ozone screen, the formation of the hydrosphere and atmosphere in its present form. There was a qualitative and quantitative leap in the development of living matter, soils were formed. The third stage is associated with the emergence of Homo sapiens and continues to this day. The main difference between this stage is the human impact on the natural environment.
The current stage in the development of the geographic envelope is characterized by the formation of natural and anthropogenic systems.
Rice. 14.1.
Until now, the question of the boundaries of the geographic envelope (GO) is debatable. The upper boundary is considered to be the ozone layer, and the lower boundary is the base of the weathering crust. Many scientists adhere to the point of view that the boundaries of the distribution of living matter in it can be considered the boundary of the geographic shell. It includes the lower layer of the atmosphere, the hydrosphere, the upper part of the lithosphere, living organisms and the layer within which human economic activity is manifested.
All earthly 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 - geographic envelope.
The geographic envelope has the following features.
- 1. Substance exists in three states of aggregation.
- 2. Various types of energy enter the geographic envelope, due to which various processes proceed. Part of the energy is conserved in the bowels of the Earth (combustible useful
fossils), some of it goes into outer space. The radiant energy of the Sun turns into heat.
- 3. A substance in a geographic envelope has a wide range of physical characteristics and chemical composition.
- 4. The geographic envelope was the place of origin and spread of life.
- 5. The geographic envelope is the place of human activity.
The geographic envelope is a natural complex of a planetary scale, its integrity is determined by the continuous exchange of matter and energy between its different parts. The structural parts of the geographic envelope are components and natural complexes.
The components of the geographic envelope are: rocks, water and air, plants and animals, and a special formation - soils. They are involved in the formation of both natural and anthropogenic landscapes.
Components differ in physical state, chemical composition. There are also differences in the level of organization: living (plants and animals), nonliving (rocks, air, water), bio-inert (soil). According to the degree of activity, the components are also divided into stable (rocks and soil), mobile (water and air), active (living organisms).
The most complex structure in the geographic envelope 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 surface layer of the atmosphere, surface and ground waters. Secondly, the upper layer of the World Ocean, and thirdly, the ocean floor. VI Vernadsky called these contact zones "films of life", because it is here that the greatest concentration of living matter is observed.
The geographic envelope has regularities: integrity, circulation of matter, rhythm, zoning.
Let's consider the essence of these patterns.
1. Integrity means the unity of the geographic envelope, which is due to the circulation of matter and energy between the components. The geographic envelope develops as a whole.
Integrity means that all components of the geographic envelope are interconnected, and a change in one component invariably entails a change in all others. Human economic activity also affects the components of the geographic envelope. Therefore, when a person intervenes in nature, it is necessary to take into account such a property of the geographical envelope as integrity.
- 2. The circulation of matter in nature is another important regularity of the geographic shell, due to which the exchange of energy takes place 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 the water cycle in the ocean. Sea currents form rings of oceanic circulation. Large currents arise between the equatorial regions and the forties. Under the influence of the Coriolis force, the currents deviate to the right, move clockwise in the Northern Hemisphere. A similar picture is developing in the Pacific Ocean. The cycle, the circulation of water in the ocean is supported by compensatory currents. The movements of water in the ocean reflect the circulation of the atmosphere, in which, therefore, the cycles of matter (air) are also observed. The circulation of the atmosphere in equatorial and temperate latitudes was discussed in more detail in Chapter 5. One should not forget about the circulation of solid matter and rocks. Magma, entering the Earth's surface, turns into effusive, i.e. igneous rocks. Under the influence of external forces, they change, collapse, are carried by water, wind or ice to other places and are deposited in the form of sedimentary deposits. Gradually, in the process of metamorphization, they turn into metamorphic rocks, and later they can turn back into igneous, etc.
- 3. Rhythm is another regularity of GO, which implies the recurrence of phenomena in time. The rhythms are daily, annual, intrasecular, 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 (illuminated and unlit parts of the day). Inanimate and living nature is subject to a daily rhythm (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 due to the annual (orbital) movement of the Earth, the change of seasons. In temperate latitudes, the seasonal rhythm is pronounced. It is susceptible to air and water temperatures, atmospheric circulation, and animal migration.
There are also intrasecular rhythms. The 11-year rhythms, which are associated with periodic changes in solar activity, are most noticeable for the geographic envelope. There are also 30-35-year cycles, they are considered as three-fold 11-year cycles. Epochs of mountain building, according to the 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 plane of the orbit.
An important regularity of the geographic 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 a different position in relation to the Sun during the year, therefore, it is illuminated and heated in different ways. The angle of incidence of the sun's rays on the earth's surface is different, which is due to the shape of the earth. At the same time, they distinguish between component geographic zoning (for example, temperature, wind, climate) and complex (geographic) one.
Along with zoning, the main features of the nature of a particular region are determined by azonal factors (azonality). This concept means the spread of any geographic object or phenomenon outside of connection with the zonal features of the territory, in "violation" of zoning. The most striking example is currents, for example, cold ones. They, passing along the coast, 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 atmospheric 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 (decrease in the amount of heat and sunlight).
The largest complex zonal subdivisions of a geographic envelope are called geographic zones. They encircle the globe in a latitudinal direction. Their separation occurs due to approximately the same amount of solar radiation. Therefore, each belt differs in radiation balance, atmospheric circulation, the rate of circulation of energy and matter, rhythm 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 the geographic zones. The geographic envelope consists of natural complexes of various ranks and sizes.
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