The outer shells of the earth. Spheres of the Earth

Life on our planet originated due to a combination of many factors. The Earth is at a favorable distance from the Sun - it does not heat up too much during the day and does not get supercooled at night. The earth has a solid surface and liquid water exists on it. The air envelope surrounding the Earth protects it from hard cosmic radiation and "bombardment" by meteorites. Our planet has unique features - its surface is encircled, interacting with each other, by several shells: solid, air and water.

Air shell - the atmosphere extends above the Earth to a height of 2-3 thousand km, but most of its mass is concentrated at the surface of the planet. The atmosphere is held together by the Earth's gravity, so its density decreases with altitude. The atmosphere contains oxygen, necessary for the respiration of living organisms. The atmosphere contains a layer of ozone, the so-called protective shield, which absorbs some of the sun's ultraviolet radiation and protects the Earth from excess ultraviolet rays. Not all planets in the solar system have a solid shell: for example, the surfaces of the giant planets - Jupiter, Saturn, Uranus and Neptune are composed of gases that are in a liquid or solid state due to high pressure and low temperatures. The solid shell of the Earth, or the lithosphere, is a huge mass of rocks on land and at the bottom of the ocean. Under the oceans and continents, it has a different thickness - from 70 to 250 km. The lithosphere is divided into large blocks - lithospheric plates.

The water shell of our planet - the hydrosphere includes all the water of the planet - in a solid, liquid and gaseous state. The hydrosphere is the seas and oceans, rivers and lakes, groundwater, swamps, glaciers, water vapor in the air and water in living organisms. The water shell redistributes the heat coming from the Sun. Slowly heating up, the water masses of the World Ocean accumulate heat, and then transfer it to the atmosphere, which softens the climate on the continents during cold periods. Involved in the world cycle, water is constantly moving: evaporating from the surfaces of the seas, oceans, lakes or rivers, it is transferred to land by clouds and falls in the form of rain or snow.

The shell of the Earth, in which life exists in all its manifestations, is called the biosphere. It includes the uppermost part of the lithosphere, the hydrosphere and the surface part of the atmosphere. The lower boundary of the biosphere is located in the earth's crust of the continents at a depth of 4-5 km, and in the air shell the sphere of life extends to the ozone layer.

All shells of the Earth influence each other. The main object of study of geography is the geographical shell - the planetary sphere, where the lower part of the atmosphere, the hydrosphere, the biosphere and the upper part of the lithosphere are intertwined and closely interact. The geographic shell develops according to daily and annual rhythms, it is influenced by eleven-year cycles of solar activity, therefore, a characteristic feature of the geographical shell is the rhythm of ongoing processes.

The geographic envelope changes from the equator to the poles and from the foothills to the tops of the mountains, it is characterized by the main patterns: integrity, unity of all components, continuity and heterogeneity.

The rapid development of human civilization has led to the appearance of a shell in which man actively influences nature. This shell is called the noosphere, or the sphere of the mind. Sometimes people change the surface of the planet even more actively than some natural processes. Gross intervention in nature, neglect of its laws can lead to the fact that over time the conditions on our planet will become unacceptable for life.

Introduction

1. Basic shells of the earth

2. Composition and physical structure of the earth

3. Geothermal regime of the earth

Conclusion

List of sources used

Introduction

Geology is the science of the structure and history of the development of the Earth. The main objects of research are rocks, in which the geological record of the Earth is imprinted, as well as modern physical processes and mechanisms acting both on its surface and in the bowels, the study of which allows us to understand how our planet developed in the past.

The earth is constantly changing. Some changes occur suddenly and very rapidly (for example, volcanic eruptions, earthquakes or large floods), but most often they occur slowly (a layer of precipitation no more than 30 cm thick is demolished or accumulated over a century). Such changes are not noticeable during the life of one person, but some information has been accumulated about changes over a long period of time, and with the help of regular accurate measurements, even insignificant movements of the earth's crust are recorded.

The history of the Earth began simultaneously with the development of the solar system about 4.6 billion years ago. However, the geological record is characterized by fragmentation and incompleteness, since many ancient rocks have been destroyed or overlain by younger sediments. Gaps need to be filled by correlation with events that have occurred elsewhere and for which more data are available, as well as by analogy and hypotheses. The relative age of rocks is determined on the basis of the complexes of fossil remains contained in them, and the deposits in which such remains are absent, on the basis of the relative position of both. In addition, the absolute age of almost all rocks can be determined by geochemical methods.

In this paper, the main shells of the earth, its composition and physical structure are considered.

1. Basic shells of the earth

The Earth has 6 shells: atmosphere, hydrosphere, biosphere, lithosphere, pyrosphere and centrosphere.

The atmosphere is the outer gaseous shell of the Earth. Its lower boundary passes through the lithosphere and hydrosphere, and the upper one - at an altitude of 1000 km. The atmosphere is divided into the troposphere (the moving layer), the stratosphere (the layer above the troposphere), and the ionosphere (the upper layer).

The average height of the troposphere is 10 km. Its mass is 75% of the total mass of the atmosphere. Air in the troposphere moves both horizontally and vertically.

The stratosphere rises 80 km above the troposphere. Its air, moving only in a horizontal direction, forms layers.

Even higher extends the ionosphere, which got its name due to the fact that its air is constantly ionized under the influence of ultraviolet and cosmic rays.

The hydrosphere covers 71% of the Earth's surface. Its average salinity is 35 g/l. The temperature of the ocean surface is from 3 to 32 ° C, the density is about 1. Sunlight penetrates to a depth of 200 m, and ultraviolet rays to a depth of 800 m.

The biosphere, or sphere of life, merges with the atmosphere, hydrosphere and lithosphere. Its upper boundary reaches the upper layers of the troposphere, while the lower one runs along the bottom of the ocean basins. The biosphere is subdivided into the sphere of plants (over 500,000 species) and the sphere of animals (over 1,000,000 species).

The lithosphere - the stone shell of the Earth - is 40 to 100 km thick. It includes continents, islands and the bottom of the oceans. The average height of the continents above ocean level: Antarctica - 2200 m, Asia - 960 m, Africa - 750 m, North America - 720 m, South America - 590 m, Europe - 340 m, Australia - 340 m.

Under the lithosphere is the pyrosphere - the fiery shell of the Earth. Its temperature rises by about 1°C for every 33 m of depth. Rocks at considerable depths are probably in a molten state due to high temperatures and high pressure.

The centrosphere, or the core of the Earth, is located at a depth of 1800 km. According to most scientists, it consists of iron and nickel. The pressure here reaches 300000000000 Pa (3000000 atmospheres), the temperature is several thousand degrees. The state of the core is still unknown.

The fiery sphere of the Earth continues to cool. The hard shell thickens, the fiery shell thickens. At one time, this led to the formation of solid boulders - continents. However, the influence of the fiery sphere on the life of planet Earth is still very great. The contours of the continents and oceans, the climate, and the composition of the atmosphere have repeatedly changed.

Exogenous and endogenous processes continuously change the solid surface of our planet, which, in turn, actively affects the Earth's biosphere.

2. Composition and physical structure of the earth

Geophysical data and the results of studying deep inclusions indicate that our planet consists of several shells with different physical properties, the change in which reflects both the change in the chemical composition of matter with depth and the change in its state of aggregation as a function of pressure.

The uppermost shell of the Earth - the earth's crust - under the continents has an average thickness of about 40 km (25-70 km), and under the oceans - only 5-10 km (without a layer of water, averaging 4.5 km). The surface of Mohorovichich is taken as the lower edge of the earth's crust - a seismic section, on which the propagation velocity of longitudinal elastic waves increases abruptly with a depth of 6.5-7.5 to 8-9 km / s, which corresponds to an increase in the density of matter from 2.8-3 .0 to 3.3 g/cm3.

From the surface of Mohorovichich to a depth of 2900 km, the Earth's mantle extends; the upper least dense zone 400 km thick stands out as the upper mantle. The interval from 2900 to 5150 km is occupied by the outer core, and from this level to the center of the Earth, i.e. from 5150 to 6371 km, is the inner core.

The Earth's core has been of interest to scientists since its discovery in 1936. It was extremely difficult to image it because of the relatively small number of seismic waves reaching it and returning to the surface. In addition, the extreme temperatures and pressures of the core have long been difficult to reproduce in the laboratory. New research could provide a more detailed picture of our planet's center. The Earth's core is divided into 2 separate regions: liquid (outer core) and solid (inner), the transition between which lies at a depth of 5,156 km.

Iron is the only element that closely matches the seismic properties of the earth's core and is abundant enough in the universe to represent approximately 35% of the planet's mass in the planet's core. According to modern data, the outer core is a rotating stream of molten iron and nickel, a good conductor of electricity. It is with him that the origin of the earth's magnetic field is associated, considering that, like a giant generator, electric currents flowing in the liquid core create a global magnetic field. The mantle layer, which is in direct contact with the outer core, is affected by it, since the temperatures in the core are higher than in the mantle. In some places, this layer generates huge heat and mass flows directed to the Earth's surface - plumes.

Characteristics of the Earth (shape, size).

The Earth is one of the nine planets that revolve around the Sun. The first ideas about the shapes and sizes of the Earth appeared in ancient times. Ancient thinkers (Pythagoras - V century BC, Aristotle - III century BC, etc.) expressed the idea that our planet has a spherical shape. Newton theoretically substantiated the position that the form represents ellipsoid of rotation, or spheroid. The difference between the polar and equatorial radii is 21 km. According to the calculations of T. D. Zhonglovich and S. I. Tropinina, the asymmetry of the Earth with respect to the equator is shown: the south pole is located closer to the equator than the north. In connection with the dissection of the relief (the presence of high mountains and deep depressions), the actual shape of the Earth is more complex than a triaxial ellipsoid. The highest point on Earth - Mount Chomolungma in the Himalayas - reaches a height of 8848m. The greatest depth of 11,034 m was found in the Mariana Trench .. In 1873, the German physicist Listing called the figure of the Earth a geoid, which literally means "earth-like." In the Soviet Union, it is currently accepted ellipsoid of F. N. Krasovsky and his students (A. A. Izotov and others), the main parameters of which are confirmed by modern research and from orbital stations. According to these data, the equatorial radius is 6378.245 km, the polar radius is 6356.863 km, and the polar compression is 1/298.25. The volume of the Earth is 1.083 10 12 km 3, and the mass is 6 10 27 g.

Outer shells of the Earth.

The outer shells of the Earth are the atmosphere, hydrosphere, and lithosphere. The gaseous shell of the Earth is the atmosphere, at the bottom it borders on the hydrosphere or lithosphere, and extends up to 1000 km. Three layers are distinguished in it: the troposphere, which is moving; after it is the stratosphere; behind it is the ionosphere (upper layer).

The size of the hydrosphere - the water shell of the Earth, is 71% of the entire surface of the planet. The average salinity of water is 35 g/l. The ocean surface has a density of approximately 1 and a temperature of 3-32 ° C. The sun's rays can penetrate no deeper than two hundred meters, and ultraviolet - 800 m.

The habitat of living organisms is the biosphere, it merges with the hydrosphere, atmosphere and lithosphere. The upper edge of the biosphere rises to the upper balls of the troposphere, and the lower reaches the bottom of the depressions in the oceans. It distinguishes the sphere of animals (more than a million species) and the sphere of plants (more than 500 thousand species).

The thickness of the lithosphere - the stone shell of the Earth, can vary from 35 to 100 km. It includes all continents, islands and the ocean floor. Below it is the pyrosphere, which is the fiery shell of our planet. There is an increase in temperature of approximately 1 ° C every 33 meters in depth. Probably, at great depths, under the influence of enormous pressure and very high temperatures, the rocks are melted and are in a state close to liquid.

Stages of the evolutionary development of the Earth

The Earth arose by thickening a predominantly high-temperature fraction with a significant amount of metallic iron, and the remaining near-Earth material, in which iron was oxidized and turned into silicates, probably went to build the Moon.

The early stages of the development of the Earth are not fixed in the stone geological record, according to which the geological sciences successfully restore its history. Even the most ancient rocks (their age is marked by a huge figure - 3.9 billion years) are the product of much later events that occurred after the formation of the planet itself.

The early stages of the existence of our planet were marked by the process of its planetary integration (accumulation) and subsequent differentiation, which led to the formation of the central core and the primary silicate mantle enveloping it. The formation of an aluminosilicate crust of oceanic and continental types belongs to later events associated with physicochemical processes in the mantle itself.

The Earth as a primary planet was formed at temperatures below the melting point of its material 5-4.6 billion years ago. The earth arose by accumulation as a chemically relatively homogeneous sphere. It was a relatively homogeneous mixture of iron particles, silicates, and less sulfides, distributed fairly evenly throughout the volume.

Most of its mass was formed at a temperature below the condensation temperature of the high-temperature fraction (metal, silicate), i.e., below 800° K. In general, the completion of the formation of the Earth could not occur below 320° K, which was dictated by the distance from the Sun. Particle impacts during the accumulation process could raise the temperature of the nascent Earth, but a quantitative estimate of the energy of this process cannot be made reliably enough.

From the beginning of the formation of the young Earth, its radioactive heating was noted, caused by the decay of rapidly dying out radioactive nuclei, including a certain number of transuranic ones that have survived from the era of nuclear fusion, and the decay of now preserved radioisotopes and.

In the total radiogenic atomic energy in the early epochs of the Earth's existence, there was enough for its material to begin to melt in places, followed by degassing and the rise of light components to the upper horizons.

With a relatively homogeneous distribution of radioactive elements with a uniform distribution of radiogenic heat over the entire volume of the Earth, the maximum temperature increase occurred in its center, followed by equalization along the periphery. However, in the central regions of the Earth, the pressure was too high for melting. Melting as a result of radioactive heating began at some critical depths, where the temperature exceeded the melting point of some part of the Earth's primary material. In this case, the iron material with an admixture of sulfur began to melt faster than pure iron or silicate.

All this happened geologically rather quickly, since the huge masses of molten iron could not remain in an unstable state for a long time in the upper parts of the Earth. In the end, all liquid iron glassed into the central regions of the Earth, forming a metallic core. The inner part of it passed into a solid dense phase under the influence of high pressure, forming a small core deeper than 5000 km.

The asymmetric process of differentiation of the planet's material began 4.5 billion years ago, which led to the appearance of continental and oceanic hemispheres (segments). It is possible that the hemisphere of the modern Pacific Ocean was the segment into which the masses of iron sank towards the center, and in the opposite hemisphere they rose with the rise of silicate material and the subsequent melting of lighter aluminosilicate masses and volatile components. The fusible fractions of the mantle material concentrated the most typical lithophile elements, which arrived together with gases and water vapor on the surface of the primary Earth. At the end of planetary differentiation, most of the silicates formed a thick mantle of the planet, and the products of its melting gave rise to the development of an aluminosilicate crust, a primary ocean, and a primary atmosphere saturated with CO 2 .

A.P. Vinogradov (1971), on the basis of an analysis of the metal phases of meteorite matter, believes that a solid iron-nickel alloy arose independently and directly from the vapor phase of a protoplanetary cloud and condensed at 1500 ° C. The iron-nickel alloy of meteorites, according to the scientist, has a primary character and correspondingly characterizes the metallic phase of the terrestrial planets. Iron-nickel alloys of rather high density, as Vinogradov believes, arose in a protoplanetary cloud, sintered due to high thermal conductivity into separate pieces that fell to the center of the gas-dust cloud, continuing continuous condensation growth. Only a mass of iron-nickel alloy, independently condensed from a protoplanetary cloud, could form the cores of terrestrial-type planets.

The high activity of the primary Sun created a magnetic field in the surrounding space, which contributed to the magnetization of ferromagnetic substances. These include metallic iron, cobalt, nickel, and partly iron sulfide. The Curie point - the temperature below which substances acquire magnetic properties - for iron is 1043 ° K, for cobalt - 1393 ° K, for nickel - 630 ° K and for iron sulfide (pyrrhotite, close to troilite) - 598 ° K. Since magnetic forces for small particles are many orders of magnitude greater than the gravitational forces of attraction, which depend on masses, then the accumulation of iron particles from the cooling solar nebula could begin at temperatures below 1000 ° K in the form of large concentrations and was many times more efficient than the accumulation of silicate particles at other equal conditions. Iron sulfide below 580°K could also accumulate under the influence of magnetic forces after iron, cobalt and nickel.

The main motif of the zonal structure of our planet was associated with the course of the successive accumulation of particles of different compositions - first, strongly ferromagnetic, then weakly ferromagnetic, and, finally, silicate and other particles, the accumulation of which was already dictated mainly by the gravitational forces of the grown massive metal masses.

Thus, the main reason for the zonal structure and composition of the earth's crust was rapid radiogenic heating, which determined the increase in its temperature and further contributed to the local melting of the material, the development of chemical differentiation and ferromagnetic properties under the influence of solar energy.

The stage of a gas-dust cloud and the formation of the Earth as a condensation in this cloud. The atmosphere contained H and Not, dissipation of these gases occurred.

In the process of gradual heating of the protoplanet, iron oxides and silicates were reduced, and the inner parts of the protoplanet were enriched with metallic iron. Various gases were released into the atmosphere. The formation of gases occurred due to radioactive, radiochemical and chemical processes. Initially, mainly inert gases were released into the atmosphere: Ne(neon), Ns(nilsborium), CO 2(carbon monoxide), H 2(hydrogen), Not(helium), Ag(argon), Kg(krypton), Heh(xenon). A restorative atmosphere was created in the atmosphere. Perhaps there was some education NH3(ammonia) through synthesis. Then, in addition to those indicated, sour smoke began to enter the atmosphere - CO 2, H 2 S, HF, SO2. Dissociation of hydrogen and helium took place. The release of water vapor and the formation of the hydrosphere caused a decrease in the concentrations of highly soluble and reactive gases ( CO2, H 2 S, NH3). The composition of the atmosphere changed accordingly.

Through volcanoes and in other ways, the release of water vapor from magma and igneous rocks continued, CO 2, SO, NH3, NO 2, SO2. There was also a selection H 2, About 2, Not, Ag, Ne, kr, Xe due to radiochemical processes and transformations of radioactive elements. gradually accumulated in the atmosphere CO 2 and N 2. There was a slight concentration About 2 in the atmosphere, but were also present in it CH 4 , H 2 and SO(from volcanoes). Oxygen oxidized these gases. As the Earth cooled, hydrogen and inert gases were absorbed by the atmosphere, retained by gravity and the geomagnetic field, like other gases of the primary atmosphere. The secondary atmosphere contained some residual hydrogen, water, ammonia, hydrogen sulfide and was of a sharply reducing character.

During the formation of the proto-Earth, all water was in various forms associated with the substance of the protoplanet. As the Earth formed from a cold protoplanet and its temperature gradually increased, water was increasingly included in the composition of the silicate magmatic solution. Part of it evaporated from the magma into the atmosphere, and then dissipated. As the Earth cooled, the dissipation of water vapor weakened, and then practically stopped altogether. The atmosphere of the Earth began to be enriched with the content of water vapor. However, atmospheric precipitation and the formation of water bodies on the Earth's surface became possible only much later, when the temperature on the Earth's surface became below 100°C. The drop in temperature on the Earth's surface to less than 100°C was undoubtedly a leap in the history of the Earth's hydrosphere. Until that moment, water in the earth's crust was only in a chemically and physically bound state, constituting, together with rocks, a single indivisible whole. Water was in the form of gas or hot vapor in the atmosphere. As the temperature of the Earth's surface fell below 100°C, rather extensive shallow reservoirs began to form on its surface, as a result of heavy rains. Since that time, seas began to form on the surface, and then the primary ocean. In the rocks of the Earth, along with water-bound solidifying magma and emerging igneous rocks, free drip-liquid water appears.

The cooling of the Earth contributed to the emergence of groundwater, which differed significantly in chemical composition between themselves and the surface waters of the primary seas. The terrestrial atmosphere, which arose during the cooling of the initial hot matter from volatile materials, vapors and gases, became the basis for the formation of the atmosphere and water in the oceans. The emergence of water on the earth's surface contributed to the process of atmospheric circulation of air masses between the sea and land. The uneven distribution of solar energy over the earth's surface has caused atmospheric circulation between the poles and the equator.

All existing elements were formed in the earth's crust. Eight of them—oxygen, silicon, aluminium, iron, calcium, sodium, potassium, and magnesium—made up more than 99% of the earth's crust by weight and number of atoms, while all the rest accounted for less than 1%. The main mass of elements is dispersed in the earth's crust and only a small part of them formed accumulations in the form of mineral deposits. In deposits, elements are usually not found in pure form. They form natural chemical compounds - minerals. Only a few - sulfur, gold and platinum - can accumulate in a pure native form.

A rock is a material from which sections of the earth's crust are built with a more or less constant composition and structure, consisting of an accumulation of several minerals. The main rock-forming process in the lithosphere is volcanism (Fig. 6.1.2). At great depths, magma is under conditions of high pressure and temperature. Magma (Greek: "thick mud") consists of a number of chemical elements or simple compounds.

Rice. 6.1.2. Eruption

With a drop in pressure and temperature, the chemical elements and their compounds are gradually "ordered", forming the prototypes of future minerals. As soon as the temperature drops enough to begin solidification, minerals begin to exude from the magma. This isolation is accompanied by a crystallization process. As an example of crystallization, we give the formation of a salt crystal NaCl(Fig. 6.1.3).

Fig.6.1.3. The structure of a crystal of table salt (sodium chloride). (Small balls are sodium atoms, large balls are chlorine atoms.)

The chemical formula indicates that the substance is built from the same number of sodium and chlorine atoms. There are no atoms of sodium chloride in nature. The substance sodium chloride is built from sodium chloride molecules. Rock salt crystals consist of sodium and chlorine atoms alternating along the axes of the cube. During crystallization, due to electromagnetic forces, each of the atoms in the crystal structure tends to take its place.

Crystallization of magma occurred in the past and occurs now during volcanic eruptions in various natural conditions. When magma solidifies at a depth, then the process of its cooling is slow, granular well-crystallized rocks appear, which are called deep. These include granites, diarites, gabbro, syanites and peridotites. Often, under the influence of the active internal forces of the Earth, magma pours out to the surface. At the surface, lava cools much faster than at depth, so the conditions for crystal formation are less favorable. Crystals are less durable and quickly turn into metamorphic, loose and sedimentary rocks.

In nature, there are no minerals and rocks that exist forever. Any rock once arose and someday its existence comes to an end. It does not disappear without a trace, but turns into another rock. So, when granite is destroyed, its particles give rise to layers of sand and clay. Sand, when submerged, can turn into sandstone and quartzite, and at higher pressure and temperature give rise to granite.

The world of minerals and rocks has its own special "life". There are twin minerals. For example, if a “lead sheen” mineral is found, then the “zinc blende” mineral will always be next to it. The same twins are gold and quartz, cinnabar and antimonite.

There are minerals "enemies" - quartz and nepheline. Quartz in composition corresponds to silica, nepheline - to sodium aluminosilicate. And although quartz is very widespread in nature and is part of many rocks, it does not “tolerate” nepheline and never occurs with it in a place. The secret of antagonism is related to the fact that nepheline is undersaturated with silica.

In the world of minerals, there are cases when one mineral turns out to be aggressive and develops at the expense of another, when environmental conditions change.

A mineral, falling into other conditions, sometimes turns out to be unstable, and is replaced by another mineral while maintaining its original form. Such transformations often occur with pyrite, which is similar in composition to iron disulfide. It usually forms golden-colored cubic crystals with a strong metallic sheen. Under the influence of atmospheric oxygen, pyrite decomposes into brown iron ore. Brown iron ore does not form crystals, but, arising in place of pyrite, retains the shape of its crystal.

Such minerals are jokingly called "deceivers". Their scientific name is pseudomorphoses, or false crystals; their shape is not characteristic of the constituent mineral.

Pseudomorphoses testify to complex relationships between different minerals. Relationships between crystals of one mineral are not always simple either. In geological museums, you have probably admired beautiful intergrowths of crystals more than once. Such intergrowths are called druze, or mountain brushes. In mineral deposits, they are the objects of reckless "hunting" of stone lovers - both beginners and experienced mineralogists (Fig. 6.1.4).

Druzes are very beautiful, so such interest in them is quite understandable. But it's not just about looks. Let's see how these brushes of crystals are formed, find out why the crystals with their elongation are always more or less perpendicular to the growth surface, why there are no or almost no crystals in druze that would lie flat or grow obliquely. It would seem that during the formation of a “nucleus” of a crystal, it should lie on the growth surface, and not stand vertically on it.

Rice. 6.1.4. Scheme of geometric selection of growing crystals during the formation of druse (according to D. P. Grigoriev).

All these questions are well explained by the theory of geometric selection of crystals by the famous mineralogist - professor of the Leningrad Mining Institute D. P. Grigoriev. He proved that a number of reasons influence the formation of crystal druses, but in any case, growing crystals interact with each other. Some of them turn out to be "weaker", so their growth soon stops. The more “strong” ones continue to grow, and in order not to be “constrained” by their neighbors, they stretch upwards.

What is the mechanism of formation of mountain brushes? How do numerous differently oriented "nuclei" turn into a small number of large crystals located more or less perpendicular to the growth surface? The answer to this question can be obtained if we carefully consider the structure of a druse, consisting of zone-colored crystals, that is, those in which color changes give out traces of growth.

Let's take a closer look at the longitudinal section of the Druse. A number of crystal nuclei are visible on the uneven growing surface. Naturally, their elongations correspond to the direction of greatest growth. Initially, all nuclei, regardless of orientation, grew at the same rate in the direction of crystal elongation. But then the crystals began to touch. The leaning ones quickly found themselves squeezed by their vertically growing neighbors, leaving no free space for them. Therefore, from the mass of differently oriented small crystals, only those that were located perpendicular or almost perpendicular to the growth surface "survived". Behind the sparkling cold brilliance of crystal druze, stored in the showcases of museums, lies a long life full of collisions...

Another remarkable mineralogical phenomenon is a rock crystal with bundles of rutile mineral inclusions. A great stone connoisseur A. A. Malakhov said that “when you turn this stone in your hands, it seems that you look at the seabed through the depths pierced by solar filaments.” In the Urals, such a stone is called “hairy”, and in the mineralogical literature it is known under the magnificent name “Hair of Venus”.

The process of crystal formation begins at some distance from the source of fiery magma, when hot aqueous solutions with silicon and titanium enter the cracks in the rocks. In the case of a decrease in temperature, the solution turns out to be supersaturated, silica crystals (rock crystal) and titanium oxide (rutile) simultaneously precipitate from it. This explains the penetration of rock crystal with rutile needles. Minerals crystallize in a certain sequence. Sometimes they stand out simultaneously, as in the formation of "Hair of Venus".

Colossal destructive and creative work is still going on in the bowels of the Earth. In chains of endless reactions, new substances are born - elements, minerals, rocks. The magma of the mantle rushes from unknown depths into the thin shell of the earth's crust, breaks through it, trying to find a way out to the surface of the planet. Waves of electromagnetic oscillations, streams of neurons, radioactive radiation stream from the bowels of the earth. It was they who became one of the main ones in the origin and development of life on Earth.

Earth is the only planet in our solar system where life originated. In many respects, this was facilitated by the presence of six different shells in it: atmosphere, hydrosphere, biosphere, lithosphere, pyrosphere and centrosphere. All of them are closely interacting with each other, which is expressed by the exchange of energy and matter. In this article we will consider their composition, main characteristics and properties.

The outer shells of the Earth are the atmosphere, hydrosphere, and lithosphere.

The gaseous shell of the Earth is the atmosphere, below it borders on the hydrosphere or lithosphere, and extends upwards for 1000 km. Three layers are distinguished in it: the troposphere, which is moving; after it is the stratosphere; behind it is the ionosphere (upper layer).

The height of the troposphere is about 10 km, and the mass is 75% of the mass of the atmosphere. It moves air in a horizontal or vertical way. Above is the stratosphere, which extends 80 km upwards. It forms layers, moving in a horizontal direction. Beyond the stratosphere is the ionosphere, in which the air is constantly ionized.

The size of the hydrosphere - the water shell of the Earth, is 71% of the entire surface of the planet. The average salinity of water is 35 g/l. The ocean surface has a density of approximately 1 and a temperature of 3-32 ° C. They are able to penetrate no deeper than two hundred meters, and ultraviolet - 800 m.

The habitat of living organisms is the biosphere, it merges with the hydrosphere, atmosphere and lithosphere. The upper edge of the biosphere rises to the upper balls of the troposphere, and the lower reaches the bottom of the depressions in the oceans. It distinguishes the sphere of animals (more than a million species) and the sphere of plants (more than 500 thousand species).

The thickness of the lithosphere - the stone shell of the Earth, can vary from 35 to 100 km. It includes all continents, islands and the ocean floor. Below it is the pyrosphere, which is the fiery shell of our planet. There is an increase in temperature of approximately 1 ° C every 33 meters in depth. Probably, at great depths, under the influence of enormous pressure and very high temperatures, the rocks are melted and are in a state close to liquid.

The location of the central shell of the Earth - the core - 1800 km deep. Most scientists support the version that it consists of nickel and iron. In it, the temperature of the components is several thousand degrees Celsius, and the pressure is 3,000,000 atmospheres. The state of the core has not yet been reliably studied, but it is known that it continues to cool.

The geospheric shells of the Earth are constantly changing: the fiery one is thickening, and the solid one is thickening. This process at one time provoked the appearance of solid stone blocks - continents. And in our time, the fiery sphere does not stop its influence on life on the planet. Its impact is very great. Constantly changing the contours of the continents, climate, oceans,

Endogenous and affect the continuous change of the solid that affects the biosphere of the planet.

All outer shells of the Earth have a common property - high mobility, due to which the slightest change in any of them immediately spreads to its entire mass. This explains why the uniformity of the composition of the shells is relative at different times, although they have undergone significant changes during geological development. For example, in the opinion of many scientists, initially there was no free oxygen in the atmosphere, but it was saturated. And later, as a result of the vital activity of plants, it acquired its current state. The composition of the Earth's water shell changed in a similar way, which is proved by the comparative indicators of the salt composition of closed waters and oceanic ones. The whole organic world changed in the same way, changes are still taking place in it.