Relief is a set of irregularities on the earth's surface of different scales, called landforms.

The relief is formed as a result of the influence of internal (endogenous) and external (exogenous) processes on the lithosphere.

Processes that form the relief and related natural phenomena.

The influence of endogenous processes on the formation of relief

Various tectonic movements of the earth's crust are associated with internal processes, creating landforms of the Earth, magmatism, and earthquakes. Tectonic movements manifest themselves in slow vertical vibrations of the earth's crust, in the formation of rock folds and faults. Slow vertical oscillatory movements - raising and lowering the earth's crust - occur continuously and everywhere. They are associated with retreat and the advance of the sea onto land. For example, the Scandinavian Peninsula is slowly rising, and the southern coast North Sea on the contrary, it goes down. Magmatism is associated primarily with deep faults that cross the earth's crust and extend into the mantle. For example, Lake Baikal is located in the zone of the Baikal or Mongolian fault, which crosses Central Asia, Eastern Siberia and the flesh goes to the Chukotka Peninsula. If magma rises through a vent, or narrow channel, at the intersection of faults, it forms hills or volcanoes with a funnel-shaped extension at the top called a crater. Most volcanoes have a cone shape (Klyuchevskaya Sopka, Fuji, Elbrus, Ararat, Vesuvius, Krakatoa, Chimborazo). Volcanoes are divided into active and extinct. Most active volcanoes are located in zones of tectonic faults, and where the formation of the earth's crust has not finished. Earthquakes are also associated with endogenous processes - sudden impacts, tremors and displacements of layers and blocks of the earth's crust. The foci of earthquakes or epicenters are confined to fault zones. In most cases, the centers of earthquakes are located at a depth of the first tens of kilometers in the earth's crust. Elastic waves arising in the source, reaching the surface, cause the formation of cracks, its oscillations up and down, and displacement in the horizontal direction. The intensity of earthquakes is assessed on a twelve-point scale, named after the German scientist Richter. During catastrophic earthquakes, the terrain changes in a matter of seconds, landslides and landslides occur in the mountains, buildings are destroyed, and people die. Earthquakes on the coast and the bottom of the oceans are the cause of tsunamis or giant waves.

Folds- wave-like bends of the layers of the earth's crust, created by the combined action of vertical and horizontal movements in the earth's crust. A fold whose layers are bent upward is called an anticlinal fold, or anticline. A fold whose layers are bent downwards is called a synclinal fold, or syncline. Synclines and anticlines are the two main forms of folds. Small and relatively simple in structure folds are expressed in the relief by low compact ridges (for example, the Sunzhensky ridge on the northern slope of the Greater Caucasus).

Larger and more complex folded structures are represented in the relief by large mountain ranges and depressions separating them (the Main and Side ranges of the Greater Caucasus). Even larger folded structures, consisting of many anticlines and synclines, form megalandforms such as a mountainous country, for example Caucasus Mountains, Ural Mountains, etc. These mountains are called folded.

Faults- these are various discontinuities in rocks, often accompanied by movement of broken parts relative to each other. The simplest type of ruptures are single, more or less deep cracks. The largest faults, extending over a significant length and width, are called deep faults.

Depending on how the broken blocks moved in the vertical direction, faults and thrusts are distinguished. Sets of faults and thrusts make up horsts and grabens. Depending on their size, they form individual mountain ranges (for example, the Table Mountains in Europe) or mountain systems and countries (for example, Altai, Tien Shan).

Volcano- a set of processes and phenomena caused by the penetration of magma into the earth’s crust and its outpouring onto the surface. From deep magma chambers, lava, hot gases, water vapor and rock fragments erupt onto the earth. Depending on the conditions and paths of magma penetration to the surface, three types of volcanic eruptions are distinguished.

Area eruptions led to the formation of vast lava plateaus. The largest of them are the Deccan Plateau on the Hindustan Peninsula and the Columbia Plateau.

Fissure eruptions sometimes occur along cracks long distance. Currently, volcanism of this type occurs in Iceland and on the ocean floor in the area of ​​mid-ocean ridges.

Central eruptions are associated with certain areas, usually at the intersection of two faults, and occur along a relatively narrow channel called a vent. This is the most common type. Volcanoes formed during such eruptions are called layered or stratovolcanoes. They look like a cone-shaped mountain with a crater on top.

Examples of such volcanoes: Kilimanjaro in Africa, Klyuchevskaya Sopka, Fuji, Etna, Hekla in Eurasia.

Exogenous processes- geological processes occurring on the surface of the Earth and in the uppermost parts of the earth’s crust (weathering, erosion, glacial activity, etc.); mainly due to energy solar radiation, gravity and the vital activity of organisms.

Erosion(from Latin erosio - erosion) - destruction of rocks and soils by surface water flows and wind, including the separation and removal of fragments of material and accompanied by their deposition.

Often, especially in foreign literature, erosion is understood as any destructive activity of geological forces, such as sea surf, glaciers, gravity; in this case, erosion is synonymous with denudation. For them, however, there are also special terms: abrasion (wave erosion), exaration (glacial erosion), gravitational processes, solifluction, etc. The same term (deflation) is used in parallel with the concept of wind erosion, but the latter is much more common.

Based on the speed of development, erosion is divided into normal and accelerated. Normal always occurs in the presence of any pronounced runoff, occurs more slowly than soil formation and does not lead to noticeable changes in the level and shape of the earth's surface. Accelerated goes faster than soil formation, leads to money R soil adation and is accompanied by a noticeable change in topography.

For reasons, natural and anthropogenic erosion are distinguished.

It should be noted that anthropogenic erosion is not always accelerated, and vice versa.

The work of glaciers- relief-forming activity of mountain and cover glaciers, consisting in the capture of rock particles by a moving glacier, their transfer and deposition when the ice melts.

Types of soil weathering

Weathering- a set of complex processes of qualitative and quantitative transformation of rocks and their constituent minerals, leading to the formation of soil. Occurs due to the action of the hydrosphere, atmosphere and biosphere on the lithosphere. If rocks long time are on the surface, then as a result of their transformations a weathering crust is formed. There are three types of weathering: physical (mechanical), chemical and biological.

Physical weathering- This is the mechanical grinding of rocks without changing their chemical structure and composition. Physical weathering begins on the surface of rocks, at points of contact with the external environment. As a result of temperature changes during the day, microcracks form on the surface of rocks, which, over time, penetrate deeper and deeper. The greater the temperature difference during the day, the faster the weathering process occurs. The next step in mechanical weathering is the entry of water into the cracks, which, when frozen, increases in volume by 1/10 of its volume, which contributes to even greater weathering of the rock. If blocks of rocks fall, for example, into a river, then there they are slowly ground down and crushed under the influence of the current. Mudflows, wind, gravity, earthquakes, and volcanic eruptions also contribute to the physical weathering of rocks. Mechanical crushing of rocks leads to the passage and retention of water and air by the rock, as well as a significant increase in surface area, which creates favorable conditions for chemical weathering.

Chemical weathering- this is a set of various chemical processes, as a result of which further destruction of rocks occurs and a qualitative change in their chemical composition with the formation of new minerals and compounds. The most important factors chemical weathering are water, carbon dioxide and oxygen. Water is an energetic solvent of rocks and minerals. The main chemical reaction of water with minerals of igneous rocks is hydrolysis, which leads to the replacement of cations of alkali and alkaline earth elements crystal lattice into hydrogen ions of dissociated water molecules.

Biological weathering produce living organisms (bacteria, fungi, viruses, burrowing animals, lower and higher plants, etc.).

Internal (endogenous) processes and their influence on the formation of relief

It is known that the relief is formed under the influence of internal (endogenous) forces of the Earth, and is modeled under the influence of external (exogenous) forces. They act constantly and simultaneously. Large landforms were formed as a result of the impact internal forces Earth, and smaller ones - under the influence of external processes, such as work surface waters, weathering.

The source of internal processes is the energy generated in the depths of the Earth. In the depths of the planet, radioactive elements decay and matter differentiates. " Driving force endogenous processes is a large circulation of matter in the mantle and lithosphere, as a result of which heating and subsequent cooling of matter occurs in them.” This leads to a change in the volume of matter, and, as a result, stresses arise in the earth’s crust, which leads to its movements. These movements are called tectonic. Their result is the emergence of mountain systems and disturbances in the occurrence of rocks. In addition, the mantle material reaches the Earth's surface, magmatism processes occur, which also influence the formation of the relief.

Thus, tectonic movements and magmatism are classified as endogenous processes.

Tectonic movements differ in direction, in speed of manifestation, in time of manifestation (modern, recent, movements of the distant geological past). As a result of tectonic movements (movement of the earth's crust), the structure of the earth's crust changes. It shifts, the primary form of occurrence of rocks changes, and discontinuities may occur: faults, horsts, grabens (Fig. 3.7).

Rice. 3.7.

Vertical movements can cover territories of different sizes. As a result of such movements, folded structures are not created, but the surface rises or falls. If vertical movements occur over a huge area, then we can talk about changes in the outlines of continents and oceans (distribution of land and sea), regression or transgression of the sea. If vertical movements do not occur in such significant areas, then lowlands and hills are formed. Such movements are still observed today. For example, it has been established that the Scandinavian Peninsula is slowly rising, while the southern part of the North Sea, on the contrary, is sinking.

• 2. Horizontal movements are most clearly manifested in the movement of lithospheric plates relative to each other, in faults in the earth’s crust, in grabens.
• 3. Movements of the earth's crust can be folded. In this case, mountain building occurs. As a rule, folding movements differ in intensity, strength and speed. Faults and cracks appear in the earth's crust. These processes are often accompanied by volcanism and earthquakes.
• 4. Earthquakes - sudden underground shocks, tremors, vibrations and displacements of layers of the earth's crust. The main reason is the movement of lithospheric plates. The sources of earthquakes are located in fault zones. The centers of earthquakes are located at a fairly large depth - these are hypocenters. Seismic waves, diverging but thicker than the earth's crust, cause destruction on the earth's surface. At the epicenter, i.e. The place that is located above the hypocenter shows the greatest destruction. The neomobilism theory provides a convincing explanation for earthquakes. At the boundaries of lithospheric plates, active seismic activity is observed, which manifests itself in the form of earthquakes. As a result, landslides, avalanches, landslides, cracks in the earth's crust form, and the appearance of the territory can change significantly.
• 5. The internal forces of the Earth also include volcanism - a set of processes associated with the penetration into the earth’s crust and the outpouring of molten and gas-saturated mineral mass onto the surface - magma Magma that has erupted to the surface and has lost its volatile components is called lava. In addition to lava, other eruption products also reach the surface - ash, stones, and various gases. They pose a great danger to humans and affect all components of the geographic envelope. Volcanoes have a very simple internal structure, but differ in external structure. The nature of the eruption can also be different, and this feature is also the basis for the classification of volcanoes. Layered volcanoes They have a regular cone shape; their cross section reveals alternating layers of lava and ash. Hawaiian-type volcanoes It is distinguished by the slow flow of lava, which slowly cools, forming shield covers. In humid climates, they often form maars - peculiar volcanoes that emit not lava and ash, but water vapor or gases.

In some cases, magma does not break out to the surface, but freezes at some depth. This is how a laccolith, an intrusive body, is formed. On globe There are 50-600 volcanoes (according to various sources), but their location is dictated by patterns: they are located in the contact zone of lithospheric plates, in moving areas of the earth’s crust. There are two zones on the globe in which the concentration is concentrated. most of volcanoes (active and extinct): Alpine-Himalayan belt and Pacific. During volcanic processes, new relief forms, lava plateaus, highlands, etc. are formed.

• Lyubushkina S.G., Pashkat. K. VChernov A. V. General geoscience: a textbook for university students studying in special fields. "Geography". M.: Education, 2004.

Factors of external and internal influence

1. Concepts of influencing factors

Before we begin discussing the concepts of factors of external and internal influence, let’s find out what is meant by external and, accordingly, internal. Soviet encyclopedic Dictionary states that “External and internal are - philosophical categories. The external expresses the properties of the object as a whole and characterizes its interaction with the environment, the internal expresses the structure and essence of the object.” Thus, we can assume that in dynamics, the external characterizes the processes of interaction of an object with the environment, and the internal characterizes the processes within the object itself.

As is known, any material object of the universe in which we exist, after its synthesis (i.e. creation or emergence) is in interaction with its environment. This interaction continues throughout the entire life cycle and ends with the disintegration of the object. It should be noted here that the term " life cycle" is quite technical and is used in technology to designate the period of existence of any technical product or systems.

The agents through which an object interacts with the environment coincide with the forms of existence of matter. In the known universe this is various types fields and flows of matter particles. All types of influence of one object on another are precisely reduced to these two varieties.

Depending on its (i.e., inherent) characteristics, an object affects its environment. The features of the object that we are talking about are mainly determined by its organization, i.e. the materials from which the object consists, its structure, its interaction components, types of energy transformation within its limits, the method of removing the products of its vital activity outside the object, or simply the loss of matter and energy during the interaction of the object with the external environment. It is known that the impact of an object on its environment inevitably, to a greater or lesser extent, changes it, and, consequently, the nature and degree of its impact on the object, i.e. this process is said to be self-consistent. In technology, the term “feedback” is used to refer to such processes.

People are designed in such a way that they try to simplify any phenomenon in the surrounding world, most often by breaking the complex into simpler ones, that is, into its constituent elements. Thus, the process of interaction with the environment is divided into separately considered processes of the influence of the environment on the object and the object on the environment. Further, in the process of the environment’s influence on an object, its individual aspects or factors are identified. The partitioning process does not end here, but we will talk about this later.

From the above it is clear how the concepts of “External influencing factors” or, as they are sometimes called, “External influencing factors” arise. (It should be noted that these concepts are absolutely identical). Thus, by factors of external influence we understand the side, process, mechanism, etc., isolated from the totality, of the influence of the environment on the object in question.

But the functioning of an object is not limited only to its interaction with the external environment; very often the interactions of its component parts seem more important in terms of their influence on the functioning of the object and the change in parameters over time. Here we come to the emergence of the concept of “Internal Impact Factors”. These should include changes over time in the properties of the materials composing the object, the types of its organization, etc.

2. Classification of impact factors

It is known that the quality of products, and by the term “product” we mean technical systems himself for various purposes, is laid down at the development stage, ensured during the production process and supported at the operation stage. When developing products, it is necessary to take into account the conditions of their operation, storage and transportation, characterized by the influence of external and internal factors.

External factors in technology include the action environment and operating features related to the installation location of the product and (or) the conditions of its transportation. These external influences may cause limitations or loss of performance of the product or its components during operation.

Internal factors for technical objects are the processes of aging and wear. Aging processes occur continuously, and they occur both during work and during storage and transportation of products. Wear occurs mainly during operation and depends on the impact external factors, on the operating modes and operation of the products. The likelihood of the influence of internal factors increases as the duration of operation increases and in case of violation of operating modes, which can be characterized by: the frequency of switching on and off, causing the products to transient processes; overvoltage; shocks, etc. Frequent switching on and switching of some products can also affect the mechanical wear of their structural elements. In products intended for cyclic operating modes, there is a significant impact on thermal conditions influence the relationship between work duration and breaks. The action of internal factors in many cases depends on the circuits and designs of products.

Depending on the time and nature of the impact, operating modes and operating modes of products can be:

continuous,

periodic (cyclic),

aperiodic (one-time use),

repeatedly – ​​intermittently,

random.

In classifications, factors are usually grouped according to some characteristic, so mechanical, climatic, etc. factors are distinguished.

The corresponding GOST divides all external influencing factors (EIF) into the following classes: mechanical, climatic, biological, radiation, electromagnetic, special environments and thermal.

In turn, each class is divided into groups, and each group into types, which, by the way, correspond to certain types of tests. For example, the class of climate impacts is divided into groups:

Atmosphere pressure,

ambient temperature.

humidity of air or other gases, etc.

Groups, in turn, are divided into the following types:

atmospheric high or low pressure,

change atmospheric pressure or its difference,

increased and, accordingly, decreased ambient temperature

change in ambient temperature, etc.

Thus, classifications of external influence factors are most often built according to the scheme

True, sometimes there are deviations from this scheme - another gradation or level is introduced - a subgroup. An example of such an exception occurs in the above classification in relation to mechanical air pumps.

Some types, groups and classes of impacts are determined by the purpose of the products and their interaction with the media, created by man in the course of his activities. These classes include the VVF classes:

special environments,

radiation,

electromagnetic,

thermal.

Space exploration led to the need to identify another class (not provided for by the standards), which included all types of so-called space influences.

One of the possible classifications of FVV is shown in Figure 1.

As we see from the classification, to mechanical factors There are two groups of them: static impact factors and dynamic impact factors. Static impact factors include such types as:

stretching,

torsion,

indentation

It is obvious that here the classification of FVV repeats the types of deformation of materials.

Mechanical factors of dynamic impact include such types as impact:

acceleration – linear or angular, which causes overloads or a state of complete or partial weightlessness,

vibration,

acoustic noise,

Among climatic factors, the following impacts are usually distinguished:

solar radiation (in the surface layers of the atmosphere);

moisture contained in the air or any other mixture of gases (moisture does not necessarily mean only water vapor - it can also be vapor of any other liquid, for example, in the atmosphere of Jupiter, the role of water is apparently played by methane, in the internal atmosphere of a spacecraft this role can be carried out by a liquid working fluid of one of its systems that got inside the apparatus as a result of leaking lines);

precipitation, which usually includes rain, frost, snow, ice, etc.

atmosphere (gas composition, presence of impurities in the form of liquid and solid aerosols, dust particles, sand.),

aerostatic or hydrostatic pressure (normal, high, low), its changes or differences.

Climatic factors can also include a factor that is generally mechanical in nature, such as the influence of environmental movement, i.e. wind, wave movement of liquid, etc.

Biological factors usually distinguish the impact on technical systems:

mold fungi and other microorganisms,

insects,

rodents

Sometimes in the form biological factor impact external environment Reptiles or animals can also act, but the likelihood of such a situation is much lower than for rodents.

It seems appropriate to include in this class VEF and human impact, which in its destructiveness and scale can exceed the impact of other biological factors.

Internal (endogenous) processes manifest themselves when the internal forces of the Earth interact with the solid shell. They are caused by the energy that accumulates in the bowels of the Earth: radioactive heat released as a result of the decay of radioactive elements, the energy of gravitational compaction and compression of the Earth’s substance, and, possibly, rotational energy associated with the rotation of the Earth around its axis.

Endogenous processes include tectonic movements of the earth's crust, magmatism, metamorphism and earthquakes.

Tectonic movements called the movement of matter in the earth's crust under the influence of processes occurring in the bowels of the Earth (in the mantle, deep and upper parts earth's crust). Over a long period of time, they create the main forms of the earth's surface - mountains and depressions. There are two types of tectonic movements: folding and rupturing, including oscillatory ones. Oscillatory movements are the most common form of tectonic movements. These are slow secular uplifts and subsidences that the earth's crust constantly experiences.

Secular oscillatory movements have great importance in the life of humanity. A gradual increase in land level changes the topographic, hydrological, geochemical conditions of soil formation, leads to increased processes of erosion, leaching, and the emergence of new relief forms. The subsidence of land leads to the accumulation of mechanical, chemical, and biogenic sediments and swamping of the area.

Movements of the earth's crust (both slow and relatively fast) play a certain role in the formation of the modern relief of the earth's surface and lead to the division of the surface into two qualitatively various areas- geosynclines and platforms.

Geosynclines, platforms, folded zones, ocean basins and reefs are among the main structural elements earth's crust. The most common types of mountains are usually confined to geosynclines, and the main types of plains are most often associated with platforms.

Secular oscillatory movements of the Earth's crust are called epeirogenic and mountain building, or orogenesis. During epeirogenesis, some areas of the land and seabed rise or fall, the boundaries of the seas expand, and this phenomenon is called transgression. When land rises, the sea retreats, which is called regression. This rise or fall of land is measured by a few millimeters per year (less often centimeters), but these processes cover large areas. For example, during this period, a rise in territory was detected in Estonia, Latvia, Lithuania, Belarus, as well as on the Scandinavian Peninsula and other regions. Land subsidence is observed near Sukhumi, on the northern coast of the Black Sea, in the depressions of the river. Kuban. In Ukraine, there is a noticeable increase in the territory of Polesie.

Mountain building, like epeirogenesis, is characterized by the slow movement of individual sections of the earth's crust. However, there is also a difference, namely that during mountain-building movements of the Earth’s crust, the occurrence of layers of layers of different rocks is disrupted. In this case, the layers either bend or break, changing their position. With such disruption of layers, the relief of large or smaller areas changes, even folded mountains are formed, for example

Carpathians, Alps, Himalayas. When layers are bent, folds are formed, and when ruptures and movements occur, skids, horsts and grabens are formed.

Volcanism in a broad sense are all those phenomena that are formed when magma rises in the Earth's crust or when lava erupts onto the earth's surface. Volcanism can be aboveground or underground.

The volcano has a channel, a crater, a cone. During an eruption, it releases gases, solid products and liquid mass - lava - to the surface. If lava flows through the crater (hole) of a volcano, then as a result of cooling, rocks are formed, which are called eruptive, or effusive. These are liparite, trachyte, andesite, diabase, basalt. If the magma did not spill out to the surface and crystallized at a certain depth, the resulting rocks are called deep-seated or intrusive. These include granite, syenite, diarite, gabbro and others.

Both extrusive and plutonic rocks are called primary crystalline rocks.

Depending on their shape, there are several types of volcanoes on the Earth’s surface: Vesuvian, Hawaiian, Maor-type volcanoes, etc. In addition, all volcanoes, depending on their action, are divided into active and inactive.

Cause of volcanism They consider mountain-building processes, as a result of which the pressure of the Earth's crust rocks on the molten magma in its depths decreases during ruptures of the thinnest earth's crust.

Earthquakes- these are movements of the earth's crust that are caused by shocks different strengths under the influence of internal forces. They occur when the balance in the earth's crust is disturbed, as a result of which some tension arises in the mass of the crust, manifested in mechanical shocks, ruptures and friction. These shocks are transmitted through rock layers to the Earth's surface. The effect of earthquakes has some connection not only with volcanism, but also with mountain building and tectonic processes.