Various landforms are formed under the action of processes that can be predominantly internal or external.

1. Internal (endogenous)- these are processes inside the Earth, in the mantle, the core, which manifest themselves on the surface of the Earth as destructive and creative. Internal processes create, first of all, large landforms on the surface of the Earth and determine the distribution of land and sea, the height of mountains, and the sharpness of their outlines. The result of their action is deep faults, deep folds, etc.

Landforms

Reservoir intrusion - a layer-like body of magma solidified at depth, having the form of a layer, the contacts of which are parallel to the layering of the host rocks.

Dikes - lamellar, clearly bounded by parallel walls of the body of intrusive igneous rocks, which penetrate the rocks sweeping them (or lie unconformably with them).

Batholith - a large massif of magma frozen at depth, having an area measured in tens of thousands of square kilometers. The shape in plan is usually elongated or isometric (has approximately equal dimensions in height, width and thickness).

stock - an intrusive body shaped like a column in vertical section. In terms of its shape is isometric, irregular. They differ from batholiths in smaller sizes.

Laccoliths - have a mushroom-shaped or dome-shaped upper surface and a relatively flat lower surface. They are formed by viscous magmas that enter either through dike-like supply channels from below or from the sill, and, propagating along the bedding, raise the host overlying rocks without disturbing their bedding. Laccoliths occur singly or in groups. Laccoliths are relatively small in size, ranging from hundreds of meters to several kilometers in diameter.

Magma solidified on the surface of the Earth forms lava flows and covers. This is an effusive type of magmatism. Modern effusive magmatism is called volcanism.

Magmatism is also associated with the occurrence earthquakes.

2. External (exogenous) processes caused by solar radiation reaching the earth. Exogenous processes smooth out irregularities, level surfaces, and fill depressions. They manifest themselves on the earth's surface both as destructive and as creative.

Destructive processes - this is the destruction of rocks, which occurs due to temperature differences, the action of wind, erosion by streams of water, moving glaciers. Creative the processes are manifested in the accumulation of particles carried by water and wind in land depressions, at the bottom of reservoirs.

The most difficult external factor is weathering.

Weathering- a set of natural processes leading to the destruction of rocks.

To astronomical factors that cause cooling on Earth are:

• tilt change earth's axis;
• deviation of the Earth from its orbit towards the distance from the Sun;
• uneven thermal radiation Sun.

TO geological factors include the processes of mountain building, volcanic activity, the movement of continents.

According to the continental drift hypothesis, huge areas of land during the history of the development of the earth's crust periodically moved from a warm climate to a cold climate, and vice versa.

GLACIAL RELIEF FORMS

trogs or trough valleys - valleys with a U-shaped profile.

punishment- bowl-shaped depressions of an armchair shape in the near-top part of the mountains with steep rocky slopes and a gently concave bottom.

"Sheep foreheads" - these are small rounded hills and uplands, composed of dense bedrock, which have been well polished by glaciers. Their slopes are asymmetrical: the slope facing down the glacier movement is slightly steeper. Often on the surface of these forms there is glacial shading, and the streaks are oriented in the direction of glacier movement.

Moraine ridges - rampart-like accumulations of products of destruction of rocks deposited by glaciers, up to several tens of meters high, up to several kilometers wide and, in most cases, many kilometers long.

Drumlins- elongated hills, shaped like a spoon, turned upside down with a convex side up. These forms are composed of deposited moraine material and in some (but not all) cases have a bedrock core.

outwash plains composed of material brought by flows of melted glacial waters, and usually adjoin the outer edge of the terminal moraines. These coarsely graded deposits consist of sand, pebbles, clay and boulders (the maximum size of which depended on the transport capacity of the flows).

Oz - these are long narrow winding ridges, composed mainly of sorted deposits (sand, gravel, pebbles, etc.), with a length of several meters to several kilometers and a height of up to 45 m.

Kamy - these are small steep hills and short ridges irregular shape composed of sorted sediments. This form of relief can be formed both by glacial water flows and simply by flowing water.

perennial, or permafrost- strata of frozen rocks that do not thaw for a long time - from several years to tens and hundreds of thousands of years.

The most common type of frozen soil deformation is heaving associated with an increase in the volume of water during freezing. The resulting positive landforms are called swelling bumps.

WORK OF FLOWING WATER

The destructive activity of flowing waters can take the form flat flush or linear blur.

Geological activity flat flush It consists in the fact that rain and melt water flowing down the slope pick up small weathering products and carry them down. Thus, the slopes are flattened, and the wash products are deposited at the bottom.

Under linear blur understand destructive activity water streams flowing in a certain direction. Linear erosion leads to the dismemberment of the slopes by ravines and river valleys.

In areas where there are readily soluble rocks (limestone, gypsum, rock salt), karst forms- funnels, caves, etc.

Karst(from him. Karst, by the name of the limestone plateau Kras in Slovenia) - a set of processes and phenomena associated with the activity of water and expressed in the dissolution of rocks and the formation of voids in them, as well as peculiar landforms that arise in areas composed of rocks that are relatively easily soluble in water - gypsum, limestone, marble, dolomite and rock salt.

river valley

Wind work (eolian processes)

The work of the wind is understood as a change in the surface of the Earth under the influence of moving air jets. Wind can break up rocks, carry small detrital material, collect it in certain places, or deposit it on the surface of the earth in an even layer. The greater the wind speed, the greater the work done by it.

A sand hill formed as a result of wind activity is dune.

Dunes are common wherever loose sands come to the surface, and the wind speed is sufficient to move them.

Their dimensions are determined by the volume of incoming sand, wind speed and the steepness of the slopes. Max speed dune movements - about 30 m per year, and height - up to 300 m.

dunes - relief mobile formations of sand in deserts, blown by the wind and not fixed by plant roots. They occur only when the direction of the prevailing wind is sufficiently constant.

The dunes can reach a height of half a meter to 100 meters. Shaped like a horseshoe or sickle, and in cross section they have a long and gentle windward slope and a short leeward slope.

Geological processes of relief formation

From the moment of formation to the present day, the Earth's crust is under the continuous influence of two forces: internal - endogenous and external - exogenous.

Endogenous processes- this is a manifestation of the internal energy of the Earth, arising in its depths. Internal processes include: tectonic, magmatic and metamorphic. Internal forces change the shape of the earth's surface: they create irregularities in the form of depressions and uplifts, and thereby give contrast to the relief.

Exogenous processes occur on the Earth's surface and at shallow depths in the Earth's crust. The sources of exogenous forces are solar energy, the action of gravity and the vital activity of organisms. External forces seek to smooth out the unevenness created by internal forces; they give the earth's surface a more or less flat shape, destroying hills, filling depressions with destruction products.

Internal and external processes are united by a common name geological.

2.5.1.1. Tectonic movements of the earth's crust

All natural movements of the earth's crust or its individual sections are called tectonic movements.

Tectonic movements in the earth's crust are constantly manifested. In some cases, they are slow, hardly noticeable to the human eye (the epoch of rest), in others - in the form of intense turbulent processes (tectonic revolutions). Mountain building, earthquakes, and volcanism are associated with tectonic movements in the earth's crust. The form, character, and intensity of destruction of the earth's surface, sedimentation, and the distribution of land and sea also depend on these movements.

The mobility of the earth's crust largely depends on the nature of its tectonic structures. The largest structures are platforms and geosynclines.

Platforms- stable, rigid, inactive structures. Platforms are characterized by leveled landforms. They consist of a hard, non-folding section of the earth's crust (crystalline base). They are characterized by calm slow movements of a vertical nature.

Geosynclines- mobile parts of the earth's crust. They are located between the platforms and are their mobile connections. Geosynclines are characterized by a variety of tectonic movements, seismic phenomena and volcanism.

The tectonic movements of the earth's crust are divided into three main interrelated types of movements:

oscillatory;

Folded;

Discontinuous.

vibrational movements are movements in which, firstly, the direction of movement is vertical, and secondly, the direction of movement periodically changes (that is, during oscillatory movements, the same section of the earth's crust alternately experiences lowering or rising). They do not cause sharp disturbances of the original bedding of rocks.

Oscillatory movements occurred in all geological stages of the development of the earth's crust and are still occurring.

At folded movements of rocks under the influence of tectonic processes are crushed into folds. The formation of artesian groundwater basins and the formation of oil fields are associated with the folded movements of the earth's crust.

At discontinuous movements create cracks. Tectonic discontinuities are shear or detachable faults. Discontinuous movements contribute to the formation of ore veins and mineral springs, but they also complicate the development of minerals.

2.5.1.2. Oscillatory movements

The oscillatory movements of the earth's crust are the most common type of tectonic movements. It has been established that there is not a single section of the earth's crust that would be in a state of complete rest.

Oscillatory movements are expressed by slow ("secular"), uneven vertical uplift of some sections of the earth's crust and lowering of others located next to them. Movement signs change, and those areas that previously experienced upward, positive movements may begin to experience downward, negative movements. Consequently, oscillatory movements represent a constantly changing, but not repetitive, wave-like process, i.e., the ups and downs following one after another do not cover the same areas, but each time they move in a wave-like manner in space.

Changes over time and movement speed. Within geosynclines, it varies from a centimeter to several units of centimeters per year, and within platforms, from fractions of a millimeter to 1.0 cm/year. Oscillatory movements in both the first and second areas occur slowly, calmly, a person and existing devices do not feel them. The presence of movements is established only by carefully studying their results.

Areas of development slow oscillatory movements may be different. Sometimes they cover vast (tens and hundreds of thousands of square kilometers) territories, and then uplifts lead to the appearance of large, but very gentle arches, and subsidence leads to the formation of similar depressions.

Large vaults and depressions are called first order structures. Movements that manifest themselves in smaller areas lead to the complication of first-order structures by second-order structures. In turn, structures of the third order arise on structures of the second order, and so on.

A change in the direction of vertical movements leads to a change in the outlines of sea basins, lakes, the direction of their geological activity, as well as the activity of other exogenous factors. When the mainland sinks, the sea sometimes covers vast areas of land (transgression), and sometimes only invades the limits of river valleys (ingression). When the mainland rises, the sea regresses, the size of the sushi is increasing.

Regressions are characterized by a vertical change of deep-water sediments by shallow ones (clays are replaced by sands, sands by pebbles). During transgression, the picture is reversed - the change of shallow-water sediments by deep-water ones.

On slow uplift indicate marine terraces, which represent a coastal area developed as a result of the work of the sea. The width of these terraces in Norway is measured in tens of meters. As a result of slow uplifts of the earth's crust at present, some ancient ports were at a fairly significant distance from the coast, the islands were attached to the continent by land bridges.

On the diving separate sections of the earth's crust indicate coastal terraces flooded with water, the presence of underwater river valleys at the mouth of rivers (Amazon, Congo), flooded mouths of rivers - estuaries (Black Sea coast), flooded forests, peat bogs, roads, human settlements.

An example of modern uplift is Scandinavia (25 mm/year). There are about five ancient coastal terraces observed in Norway. The northern part of Finland is rising at a rate of 1 cm per year. The area of ​​Finland will increase by about 1000 km 2 in 100 years.

Subsidence is especially typical for the Netherlands (40–60 mm/year). Residents protect the country from flooding complex system dams, dams, constantly monitor their safety. 2/3 of the Netherlands is below sea level.

In Russia, the areas of Kursk are rising (3.6 mm/year), the Central Russian Upland (1.5–2 mm/year), new earth, Northern Caspian. Subsidence occurs in the area between Moscow and St. Petersburg (3.7 mm/year), in the Azov-Kuban depression (3–5 mm/year), in the Tver depression (5–7 mm/year) and in other places.

Endogenous and exogenous factors (processes) of relief formation. Endogenous landforms

The relief is formed as a result of the interaction of internal (endogenous) and external (exogenous) forces. Endogenous and exogenous processes of relief formation operate constantly. At the same time, endogenous processes mainly create the main features of the relief, while exogenous ones try to level the relief.

The main sources of energy in relief formation are:

• 1. Internal energy of the Earth;
• 2. Solar energy;
• 3. Gravity;
• 4. Influence of space.

Energy source endogenous processes is the thermal energy of the Earth associated with the processes occurring in the mantle (radioactive decay). Due to endogenous forces, the earth's crust was separated from the mantle with the formation of its two types: continental and oceanic.

Endogenous forces cause: movements of the lithosphere, the formation of folds and faults, earthquakes and volcanism. All these movements are reflected in the relief and lead to the formation of mountains and troughs of the earth's crust.

Faults in the earth's crust distinguished by: size, shape and time of formation. Deep faults form large blocks of the earth's crust, which experience vertical and horizontal displacements. Such faults often define the outlines of continents.

Exogenous processes associated with land solar energy. But they flow with the participation of gravity. When this happens:

• 1. Weathering of rocks;
• 2. Movement of material under the action of gravity (landslides, landslides, screes on slopes);
• 3. Material transport by water and wind.

weathering called the totality of processes of mechanical destruction and chemical change of rocks.

The total impact of all processes of destruction and transport of rocks is called denudation. Denudation leads to leveling of the surface of the lithosphere. If there were no endogenous processes on the Earth, then it would have had a completely flat surface long ago. This surface is called the main level of denudation.

In reality, there are many temporal levels of denudation at which equalization processes may fade for some time.

The manifestation of denudation processes depends on: the composition of rocks, geological structure and climate.

Endogenous landforms subdivided into planetary, tectonic and volcanic forms, very closely related to each other.

Planetary and tectonic landforms in their origin and development are due to the processes of formation of the earth's crust and tectonic movements. The largest greatest forms the relief of the planet are mainland ledges And oceanic depressions. They arise as a result of global processes of tectogenesis and reflect fundamental differences not only in the structure of the earth's crust, but also in the upper mantle. The continents are vast uplands with an average height of about +0.8 km above sea level, the oceans are even more grandiose depressions with an average depth of 4.2. The second category of endogenous forms, which has a lot in common with the previous one, is largest forms relief of the planet - mega-relief, complicating the structure of both continental and oceanic spaces. A number of researchers consider most of these forms as planetary and refer to the previous category. However, the development of the largest landforms is more closely related to the actual tectonic processes. In places, these forms pass from the oceanic to the continental region, as if superimposed on them. These include continental platform plains, largest systems high mountains and deep depressions, systems of island arcs and deep trenches, mid-ocean ridges and abyssal oceanic plains. These landforms are associated with the development of second-order tectonic structures - mobile belts and stable platforms.

Forces constantly act on the earth's surface, changing the earth's crust, contributing to the formation of relief. All these processes are different, but they can be combined into two groups: external (or exogenous) and internal (or endogenous). Exogenous processes operate on the surface of the Earth, and endogenous - deep processes, the sources of which are located in the bowels of the planet. From the outside, the forces of attraction of the Moon and the Sun act on the Earth. The power of attraction of others celestial bodies very small, but some scientists believe that in the geological history of the Earth, gravitational influences from space may increase. Many scientists refer to external or exogenous forces as Earth gravity, due to which landslides, landslides occur in the mountains, glaciers move from the mountains.

Exogenous forces destroy, transform the earth's crust, transfer loose and soluble products of destruction carried out by water, wind, and glaciers. Simultaneously with destruction, there is also a process of accumulation, or accumulation of destruction products. The destructive effects of exogenous processes are often undesirable and even dangerous for humans. Such dangerous phenomena include, for example, mudflows and stone flows. They can demolish bridges, dams, destroy crops. Landslides are also dangerous, which also lead to the destruction of various buildings, thereby causing damage to the economy, taking the lives of people. Among the exogenous processes, it is necessary to note the weathering, which leads to the leveling of the relief, as well as the role of the wind.

Endogenous processes raise individual sections of the earth's crust. They contribute to the formation of large landforms - megaforms and macroforms. The main source of energy for endogenous processes is the internal heat in the bowels of the Earth. These processes cause the movement of magma, volcanic activity, earthquakes, slow vibrations of the earth's crust. Internal forces work in the bowels of the planet and are completely hidden from our eyes.

Thus, the development of the earth's crust, the formation of relief are the result of the combined action of internal (endogenous) and external (exogenous) forces and processes. They act as two opposite sides of a single process. Thanks to endogenous, mainly creative processes, large landforms are formed - plains, mountain systems. Exogenous processes mainly destroy and level the earth's surface, but at the same time form smaller (microforms) landforms - ravines, river valleys, and also accumulate destruction products.

Processes influencing the formation of the earth's crust wikipedia
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Platforms of the lithosphere

Platforms are relatively stable areas of the earth's crust. They arise on the site of previously existing highly mobile folded structures, formed during the closure of geosynclinal systems, by their successive transformation into tectonically stable areas.

A characteristic feature of the structure of all lithospheric platforms of the Earth is their structure of two tiers or floors.

The lower structural floor is also called the foundation. The foundation is composed of highly deformed metamorphosed and granitized rocks, penetrated by intrusions and tectonic faults.

According to the time of formation of the foundation, the platforms are divided into ancient and young.

The ancient platforms, which also make up the core of modern continents and are called cratons, are of Precambrian age and formed mainly by the beginning of the Late Proterozoic. Ancient platforms are divided into 3 types: Laurasian, Gondwana and transitional.

The first type includes the North American (Lawrence), East European and Siberian (Angaris) platforms, formed as a result of the breakup of the supercontinent Laurasia, which in turn was formed after the breakup of the Pangea protocontinent.

To the second: South American, African-Arabian, Hindustan, Australian and Antarctic. The Antarctic platform before the Paleozoic era was divided into the Western and Eastern platforms, which united only in the Paleozoic era. The African platform in the Archaean was divided into the Congo (Zaire), Kalahari (South African), Somalia (East African), Madagascar, Arabia, Sudan, and Sahara protoplatforms. After the collapse of the Pangea supercontinent, the African protoplatforms, with the exception of Arabian and Madagascar, united. The final unification took place in the Paleozoic era, when the African platform turned into the African-Arabian platform as part of Gondwana.

The third intermediate type includes small-sized platforms: Sino-Korean (Huanhe) and South China (Yangtze), which at different times were both part of Laurasia and Gondwana.

Archean and Early Proterozoic formations participate in the foundation of ancient platforms. Within the South American and African platforms, part of the formations belongs to the Upper Proterozoic time. The formations are deeply metamorphosed (amphibolite and granulite facies of metamorphism); leading role gneisses and crystalline schists play among them, granites are widespread. Therefore, such a foundation is called granite-gneiss or crystalline.

Young platforms formed in the Paleozoic or Late Cambrian time, they border the ancient platforms. Their area is only 5% of the total area of ​​the continents. The foundations of the platforms are composed of Phanerozoic sedimentary-volcanic rocks that experienced weak (greenschist facies) or even only initial metamorphism. There are blocks of more deeply metamorphosed ancient, Precambrian rocks. Granites and other intrusive formations, among which ophiolite belts should be noted, play a subordinate role in the composition. In contrast to the foundation of ancient platforms, the foundation of young ones is called folded.

Depending on the time of completion of the basement deformations, the division of young platforms into Epibaikalian (the most ancient), Epicaledonian and Epihercynian.

The first type includes the Timan-Pechora and Mysian platforms of European Russia.

The second type includes the West Siberian and East Australian platforms.

To the third: the Ural-Siberian, Central Asian and Ciscaucasian platforms.

Between the basement and the sedimentary cover of young platforms, an intermediate layer is often distinguished, which includes formations of two types: sedimentary, molasse or molasse-volcanic filling of intermountain depressions of the last orogenic stage in the development of the mobile belt that preceded the formation of the platform; detrital and detrital-volcanogenic filling of grabens formed at the stage of transition from the orogenic stage to the early platform

The upper structural stage or platform cover is composed of non-metamorphosed sedimentary rocks: carbonate and shallow sandy-clayey in platform seas; lacustrine, alluvial and bog in a humid climate on the site of the former seas; eolian and lagoonal in arid climate. The rocks occur horizontally with erosion and unconformity at the base. The thickness of the sedimentary cover is usually 2-4 km.

In a number of places, the sedimentary layer is absent as a result of uplift or erosion, and the foundation comes to the surface. Such sections of platforms are called shields.

Influence of internal and external processes on the formation of relief

On the territory of Russia, the Baltic, Aldan and Anabar shields are known. Within the shields of ancient platforms, three complexes of rocks of the Archean and Lower Proterozoic age are distinguished:

Greenstone belts, represented by thick strata of regularly alternating rocks from ultrabasic and basic volcanics (from basalts and andesites to dacites and rhyolites) to granites. Their length is up to 1000 km with a width of up to 200 km.

Complexes of ortho- and para-gneisses, which, in combination with granite massifs, form fields of granite-gneisses. Gneisses correspond in composition to granites and have a gneiss-like texture.

Granulitic (granulite-gneiss) belts, which are metamorphic rocks formed under conditions of medium pressure and high temperatures (750-1000 ° C) and containing quartz, feldspar and garnet.

Areas where the foundation is covered everywhere by a thick sedimentary cover are called slabs. Most of the young platforms are sometimes referred to simply as slabs for this reason.

The largest elements of the platforms are syneclises: extensive depressions or troughs with slopes of only a few minutes, which correspond to the first meters per kilometer of movement. As an example, we can name the Moscow syneclise with its center near the city of the same name and the Caspian syneclise within the Caspian lowland. In contrast to syneclises, large platform uplifts are called anteclises. On the European territory of Russia, the Belarusian, Voronezh and Volga-Ural anteclises are known.

Grabens or aulacogens are also large negative elements of the platforms: narrow, extended sections, linearly oriented and limited by deep faults. There are simple and complex. In the latter case, along with deflections, they include uplifts - horsts. Effusive and intrusive magmatism is developed along the aulacogenes, which is associated with the formation of volcanic covers and explosion pipes. All igneous rocks within the platforms are called traps.

Smaller elements are shafts, domes, etc.

Lithospheric platforms experience vertical oscillatory movements: they rise or fall. Such movements are associated with the transgressions and regressions of the sea that have repeatedly occurred throughout the entire geological history of the Earth.

In Central Asia, the formation of the mountain belts of Central Asia: Tien Shan, Altai, Sayan, etc. is associated with the latest tectonic movements of the platforms. Such mountains are called revived (epiplatforms or epiplatform orogenic belts or secondary orogens). They are formed during orrogenesis epochs in areas adjacent to geosynclinal belts.

1. Relief change under the influence of internal processes

Klestov Svyatoslav, Sadovnikov Danil 8b

2.

The relief is a set of irregularities of the earth
surfaces of different scales, called shapes
relief.
The relief is formed as a result of the impact on
lithosphere of internal (endogenous) and external
(exogenous) processes.
Processes forming the relief and related to them
natural phenomena.

3. Processes that change the relief

Volcanism -
a set of processes and phenomena associated with the movement of magma (together with
gases and steam) in the upper mantle and the earth's crust, its outpouring in the form of lava or
ejection to the surface volcanic eruptions
Earthquakes -
These are tremors and vibrations of the earth's surface. According to modern
view, earthquakes reflect the process of geological transformation
planets.
Tectonic movements -
this mechanical movements the earth's crust, caused by forces that act
in the Earth's crust and mainly in the Earth's mantle, leading to deformation
rocks that make up the crust.

4. Volcanism

In Russia, the vast majority of volcanic mountains and all active volcanoes
located in the east of the country - on the Kamchatka Peninsula and the Kuril Islands.
This territory belongs to the so-called "ring of fire", within
which contains more than 2/3 of the active volcanoes of the planet. Here
there is a grandiose tectonic process of interaction between two large
lithospheric plates - Pacific and Sea of ​​Okhotsk. Wherein Earth's crust Pacific
ocean, older and heavier, sinks (subducts) under the Sea of ​​Okhotsk and,
remelted at great depths, gives rise to magma chambers that feed
volcanoes of Kamchatka and the Kuriles.
About 30 active and more than 160 extinct volcanoes are now known in Kamchatka.
Most often strong and catastrophic eruptions in the Holocene (over the last 10
thousand

years) took place on two volcanoes - Avachinsky Sopka and Shiveluch.
Volcano Klyuchevskaya Sopka - the largest active volcano in Eurasia (4,688 m) -
known for its perfect, extraordinarily beautiful cone. For the first time
the eruption of Klyuchevskaya Sopka volcano was described in 1697 by the pioneer of Kamchatka
Vladimir Atlasov. On average, a volcanic eruption occurs once every five years, and in
separate periods - annually, sometimes for several years, and
accompanied by explosions and ash falls.

5. Volcano eruption Klyuchevskaya Sopka

6.

internal and external processes of the earth

earthquakes

On the territory of Russia, earthquakes occur in mountainous areas, at the junction
tectonic plates - Caucasus, Altai, Western Siberia, Eastern Siberia, Kamchatka.
Most earthquakes in Russia occur in remote, sparsely populated
areas, but those earthquakes that occur in populated areas on average 5-6
once a century, many human lives are taken away, houses and villages are destroyed. So
during the earthquake on Sakhalin in 1995, the village was completely destroyed
Neftegorsk. Most earthquakes occur in Kamchatka and the Kuril
islands, sometimes accompanied by tsunamis. Due to an earthquake in pacific ocean
off the coast of Kamchatka in 1952, a tsunami formed, which completely destroyed
city ​​of Severo-Kurilsk.
Earthquakes occur due to the collision of lithospheric plates, so in the Caucasus
The Arabian Plate is moving north into the Eurasian Plate. On Kamchatka
The Pacific Plate collides with the Eurasian Plate, and volcanic activity
is one of the causes of small tremors occurring in
close proximity to the volcano or on it.

7. Neftegorsk earthquake (1995)

8. Tectonic movements in Russia

As a result of a long history of geological development on the territory of Russia,
the main types of geotectures are flat-platform areas and large orogenic mobile
belts.

However, within the same geotectures, completely different geotextures are often distributed.
relief (low basement plains of Karelia and the Aldan highlands on the shields of ancient platforms;
low Ural mountains and high-altitude Altai within the Ural-Mongolian belt, etc.);
on the contrary, a similar relief can form within different geotectures (high-mountain
Caucasus and Altai). This is due to the great influence on the modern relief of neotectonic
movements that began in the Oligocene (Upper Paleogene) and continue to the present
time.
After a period of relative tectonic calm at the beginning of the Cenozoic, when
low plains and practically no mountains have been preserved (only in the area of ​​​​Mesozoic folding
in some places, apparently, small hills and low mountains were preserved), vast areas of Western
Siberia and the south of the East European Plain were covered with the waters of shallow sea
pools. began in the Oligocene new period tectonic activation - neotectonic
a stage that led to a radical restructuring of the relief.
Recent tectonic movements and morphostructures. Neotectonics, or the latest
tectonic movements, V.A. Obruchev defined as the movements of the earth's crust that created
modern relief. It is with the latest (Neogene-Quaternary) movements that
formation and distribution of morphostructures on the territory of Russia - large landforms,
resulting from the interaction of endogenous and exogenous processes with the leading role
first.

9.

Altai mountains

Relief change under the influence of internal processes

English RussianRules

The relief is formed mainly as a result of a long-term simultaneous impact on the earth's surface of endogenous (internal) and exogenous (external) processes.

Processes affecting the formation of the earth's crust

The relief is studied by geomorphology. Endogenous processes are relief-forming processes that occur mainly in the bowels of the Earth and are due to its internal energy, gravity and forces arising from the rotation of the Earth. Endogenous processes manifest themselves in the form of tectonic movements, magmatism, in the activity of mud volcanoes, etc. Endogenous processes play a major role in the formation of large landforms. Exogenous processes - relief-forming processes occurring on the surface of the Earth and in the uppermost parts of the earth's crust: weathering, erosion, denudation, abrasion, glacier activity, etc. Exogenous processes are mainly due to the energy of solar radiation, gravity and vital activity of organisms. Exogenous processes form predominantly meso and microrelief forms.

what forces created the continents

Superintelligence above)

1) human activity 2) weathering 3) activity of groundwater 4) movement of plates of the lithosphere 5) activity of flowing water

Geological processes of formation and development of the earth's crust and relief

When studying this topic, it is important to understand the essence of endogenous and exogenous processes, to have a correct understanding of the interaction of endogenous and exogenous forces and the role of this interaction in creating the relief of the earth's surface and soil-forming rocks.

On the surface of the Earth and in its interior, geological processes take place, which are usually divided into two large groups according to energy sources: 1) endogenous and 2) exogenous.

Exogenous processes arise as a result of external influence on the globe (atmosphere, hydrosphere, biosphere) and appear on its surface. They are mainly generated by the thermal energy of the Sun, which enters the earth and is transformed into other types of energy.

Endogenous processes are manifested when the internal forces of the Earth act on a solid shell. They are due to the energy that accumulates in the bowels of the Earth. Endogenous processes include: magmatism, metamorphism, tectonic movements of the earth's crust (epeirogenesis and orogeny) and earthquakes.

You should know that many hot springs (terms) and their variety - geysers (periodically spouting) are associated with the activity of volcanoes, which bring to the surface a large number of minerals, forming mineral cones (geyserites).

In conclusion, it should be pointed out that volcanism plays an important role in the processes of soil formation and influences the properties of modern soil cover.

With intrusive magmatism (plutonism), magma penetrates into the earth's crust, before reaching the surface of the Earth, immediately solidifies, forming magmatic bodies of various shapes - intrusions (batholiths, stocks, laccoliths, phacoliths, lopolites, chonoliths).

Magmatic activity is the main cause of mountainous relief.

The processes of change and transformation of rocks occurring inside the Earth were called metamorphism. When studying this process, pay attention to the causes and main types of metamorphism, among which are contact metamorphism, regional and dynamometamorphism.

tectonic movements called the movement of the substance of the earth's crust under the influence of processes occurring in the bowels of the earth (in the mantle, in the deep and upper parts of the earth's crust).

Tectonic movements of the earth's crust create for a long time the main forms of the earth's surface - mountains and depressions.

There are two types of tectonic movements: folded and discontinuous, or orogenic(creating mountains), and oscillatory, or epeirogenic(creating continents).

All tectonic movements are mutually interconnected, folded and discontinuous movements can pass into each other, as a result of their action, earthquakes occur in the earth's crust, and the formation of deposits of many minerals (oil, coal, etc.) is associated with them.

Oscillatory (epeirogenic) movements - the most common form of tectonic movement. These are slow secular ups and downs that the earth's crust is constantly experiencing.

Secular oscillatory movements are of great importance in the life of mankind.

The gradual rise in land level changes the topographic, hydrological, geochemical conditions of soil formation, leads to increased erosion, leaching, and the emergence of new landforms. The subsidence of the land leads to the accumulation of mechanical, chemical, biogenic precipitation, and the swamping of the area.

Along with the phenomena of secular duration, there are phenomena of modern seismotectonics - earthquakes and seaquakes.

When studying this phenomenon, one should consider the geographic distribution of earthquakes, the causes, consequences of earthquakes and their prediction.

In conclusion, it should be emphasized that the movements of the earth's crust (both slow and relatively fast) play a decisive 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.

Exogenous processes are processes of external dynamics. They flow on the surface of the Earth or at a shallow depth in the earth's crust under the influence of forces caused by the energy of solar radiation, gravity, vital activity of plant and animal organisms and human activity. The exogenous processes that transform the relief of the continents include: weathering, various slope processes, the activity of flowing water, the activity of oceans and seas, lakes, ice and snow, permafrost processes, the activity of wind, groundwater, processes caused by human activity, biogenic processes.

When considering exogenous processes, it is necessary to understand not only the essence of each of them, but also to understand their role in the formation of relief and the formation of deposits and to study them.

It should be clearly understood that weathering, which is the first link in the system of exogenous processes, promotes the transformation of rocks into loose material and prepares it for transport.

As a result of the destruction of rocks, various weathering products are formed: mobile, which are carried away under the influence of gravity, planar washout, and residual, which remain at the site of destruction and are called eluvium.

Eluvium is one of the important genetic types of continental deposits. Eluvial formations that make up the most upper part lithosphere are called weathering crust.

As a result of weathering, rocks are subjected to deep physical and chemical changes and acquire a number of new properties favorable for plant life (air permeability, water permeability, duty cycle, moisture capacity, absorption capacity, stock of ash nutrients available to organisms).

Weathering has little effect directly on the relief, but weathering processes destroy rocks, thereby facilitating the impact of denudation agents on them.

wind activity consists of the processes of deflation (blowing and waving), corrosion (turning), transfer and accumulation (deposition).

Having mastered the main features of wind activity, one should study the forms of eolian relief (deflationary and accumulative) and eolian deposits (sands and loesses).

Activity of surface flowing waters(fluvial processes). Consideration of this issue should begin with the study of surface runoff, which is widespread on the surface of the continents and determines the main features of their landscapes in almost all physical and geographical zones (excluding the zone of deserts and eternal snows) both in the mountains and on the plains.

When studying the activity of surface waters, first of all, it should be understood that their work consists in flushing, erosion of the surface (erosion), transportation and accumulation of erosion products (accumulation). The combination of erosion and accumulation processes determines the formation of forms of erosional and accumulative reliefs.

Temporary flows in the form of non-conditional runoff (flat wash) carry material along the slope and lead to the formation of deluvial and proluvial deposits, which are a kind of genetic type of continental deposits.

It is important to understand that planar washout can easily turn into linear washout where unevenness has appeared on the slopes, the vegetation cover has been disturbed, and there are cracks in the soil. The flowing waters, gathering in depressions, linger and erode the soil. At the site of the beginning erosion, a rut first forms, then a gully, and finally a ravine.

Unlike temporary streams, rivers are permanent streams. Rivers are constantly doing not only erosive work, but also the work of transporting and depositing material.

Studying the structure of the river valley according to the textbook, one should make a profile drawing (longitudinal and transverse), showing on it the floodplain, terraces, and primary slopes.

It is necessary to consider the formation of characteristic forms of floodplain relief (microrelief), which includes near-river ridges, crests and depressions between crests, oxbow depressions, and to study the main types of alluvium (channel, floodplain).

It is important to understand that the floodplain, terraces, bedrocks and the valley as a whole are the result of the migration of the river channel in plan and in the vertical direction. The direction of displacement and its intensity are entirely determined by the position of the erosion base, tectonic movements, and the hydrological regime of the watercourse, which depends on the climate.

The study of fluvial processes should be completed by examining the role of flowing waters in the transformation of the earth's surface topography.

Activities of the seas and lakes. The sea occupies about 71% of the earth's surface and performs a variety of work on the destruction of rocks, the transfer of destroyed material and its accumulation and the creation of new rocks, with sediment accumulation processes predominating.

In the formation of the modern relief of the coasts, the repeated change of land by the sea played a role, especially transgressions in the Neogene and Quaternary periods. The result of these transgressions are the marine accumulative plains of the North of Russia and the Caspian lowland.

The activity of lakes is similar to the work of the sea and differs from it mainly only in its scale.

To groundwater includes all waters located in the pores and cracks of rocks. Groundwater is a special kind of mineral resources. They are gaining more and more economic importance. Various manifestations of their activity and interaction with soil waters are specific objects of observation for soil scientists and agronomists. Particular attention should be paid to karst, suffosion, landslide and solifluction processes and landforms, various types of chemogenic accumulation and groundwater mineralization.

The depth of groundwater occurrence, the degree of their mineralization have a great influence on the properties of soils, the nature of vegetation and the processes occurring in them (gleying, swamping, salinization), form the landscape features of the area.

When studying the activity of groundwater, it is important to understand the essence of karst phenomena and the conditions that favor their development, and to understand the general features of karst landforms. In karst areas, the leading processes are the dissolution and leaching of rocks, which take place under the conditions of the prevailing vertical circulation of groundwater, in readily soluble and permeable rocks.

The activity of snow and ice. Glaciers do a lot of destructive and creative work. Thanks to their activity, the relief of the earth's surface is modified, a significant amount of detrital material moves and various precipitation accumulates.

When studying this issue, attention should be paid to a number of general issues of glacier activity, namely: the concept of the snow boundary, the conditions for the formation and development of glaciers. Without a good understanding of these concepts, it is difficult to understand the remaining issues of the topic.

The relief of areas dominated by glacial drift is represented by forms of glacial processing, hatching and polishing: curly rocks, sheep foreheads and forms of glacial ploughing: depressions, basins.

The relief of areas dominated by glacial accumulation is represented by hilly-morainic, end-morainic, and drumlin landscapes.

The relief of the non-glacial regions is associated with the activity of glacial melt waters and is represented by outwash plains, near-glacial lakes, eskers and kames.

In the post-glacial period, the moraine and water-glacial relief changed under the influence of planar washout, solifluction, erosion and tectonic movements (smoothing of hills and filling of lake depressions, descent of lakes, development of a ravine-gully network, formation of floodplains and terraces, formation of dunes).

In conclusion of the study of the section, carefully study the properties of all types of sediments associated with the activity of the glacier and water-glacial flows.

Beneath the permafrost understand such a state of rocks in which they retain negative temperatures for a long time (hundreds and thousands of years).

Considering this issue, it is necessary to study the causes of occurrence and the limits of distribution permafrost.

The presence of frozen rocks at a shallow depth causes the development of special phenomena (thermokarst and solifluction) and creates a peculiar complex of relief forms - solifluction terraces (sinter forms), upland terraces (stepped forms of mountain slopes), large peat mounds (during heaving processes), ice, hydrolaccoliths, polygonal formations.

When studying this issue, the student must understand not only the causes, nature and boundaries of the spread of permafrost, but also the impact that the presence of permafrost has on the soil formation process, the specifics of agriculture and the organization and implementation of engineering work in permafrost areas.

Questions for self-examination

Endogenous and exogenous processes of transformation of the earth's crust, features of their manifestation. Their unity and interconnection and sources of energy.

2. Folding disturbances, folds, their types (synclines and anticlines), significance in the formation of minerals.

3. Breaks in the earth's crust, their types, significance for soil formation and accumulation of minerals.

4. Chemical weathering of rocks. Name the main chemical reactions. Give the concept of eluvium and weathering crust.

5. Name the types of deserts.

6. Compare glacial and water-glacial landforms and sediments.

7. Describe the main links of the hydrographic network (gully, ravine, beam, valley).

Development of landforms

Make a schematic sketch of the river valley and show the floodplain, terrace, bedrock slopes.

9. Geological activity of lakes and swamps, their types, deposits, national economic significance.

10. What are the features of relief formation in permafrost?

11. Name the types of relief (morphological and genetic) and categories of relief by dimension.

12. Study individual landforms in your area and explain their origin.

13. The concept of the landscape and its evolution in connection with the evolution of the relief.

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landform

Questions for students:

- Who remembers from the 6th grade course what relief is? (Relief - a set of irregularities of the earth's surface). Students write this definition in the dictionary, which is located on the back of the notebook.

- Remember what landforms you know and fill in the diagram on the board. On the board, the teacher hangs a diagram of inverted cards with terms:

Fig.1. Flowchart “Earth Relief”

Students complete the chart in their notebooks.

Teacher's story.

Relief - the totality of all the irregularities of the earth's surface

The surface of the Earth, of course, is not completely flat. The height difference on it from the Himalayas to the Mariana Trench reaches two tens of kilometers.

How relief is formed

The relief of our planet continues to form even now: lithospheric plates collide, crushing into the folds of mountains, volcanoes erupt, rivers and rains wash away rocks. If we were on Earth in a few hundred million years, we would no longer recognize the map of our home planet, and all the plains and mountain systems during this time would have changed beyond recognition. All processes that form the Earth's relief can be divided into two large groups: internal and external. Otherwise, internal can be called endogenous. These include subsidence and uplift of the crust, volcanism, earthquakes, plate movement. External ones are called exogenous - this is the activity of flowing waters, winds, waves, glaciers, as well as animals and plants. The surface of the planet is also increasingly influenced by man himself. The human factor can be divided into another group, calling it anthropogenic forces.

landform

Plains

Lowlands - up to 200 m

Hills - 200-500 m

Plateau - more than 500 m

The mountains

Low - 500-1000 m

Medium - 1000 - 2000 m

High - 2000 - 5000 m

The highest - more than 5000 m

Relief of the oceans

Basins - depressions in the bed of the oceans

Mid-ocean ridges are faults that form a single mountain system at the bottom of all oceans with a total length of more than 60 thousand km. In the middle part of these faults there are deep gorges, reaching the mantle itself.

At their bottom, there is a constant process of spreading - the outpouring of the mantle with the formation of a new earth's crust.

Deep sea trenches are long, narrow depressions on the ocean floor that are more than 6 km deep. The deepest in the world is the Mariana Trench, 11 km 22 m deep.

Island arcs are elongated groups of islands rising from the ocean floor above the surface of the water. (For example, the Kuril and Japanese islands) They can be adjacent to a deep-sea trench and are formed as a result of the fact that the oceanic crust next to the trench begins to rise above sea level due to the subduction processes occurring in it - the submergence of one lithospheric plate in this place under another.

2. Formation of plains and mountains

The teacher constructs an explanation according to this scheme. In the course of the teacher's story, the students transfer the diagram to their notebooks.

Rice. 2. Formation of plains

Planation. The oceanic crust (soft and thin) is easily folded into folds, and mountains can form in its place. Then the rocks that compose it rise to a height of several kilometers above sea level. This happens as a result of intense compression. The thickness of the earth's crust increases to 50 km.

Barely born, the mountains begin to slowly but steadily collapse under the influence of external forces - wind, water flows, glaciers, and simply temperature changes. In the foothill and intermountain troughs, a large amount of clastic rocks accumulate, with smaller ones at the bottom, and increasingly coarser ones at the top.

Old (blocky, revived) mountains. The oceanic earth's crust was crumpled into folds, they collapsed to the state of plains, then the Alpine era of folding revived the mountainous relief in the place of the destroyed mountain structures. These low mountains have a small height and the appearance of blocks. Further, students, working with tectonic and physical cards, give examples of ancient mountains (Ural, Appalachian, Scandinavian, Draconian, Great Dividing Range, etc.)

Rice. 3. Formation of old (blocky, revived) mountains

Rice. 4. Ural Mountains

The middle (fold-block) mountains were formed in the same way as the ancient ones, but the destruction did not bring them to the state of plains. Their block formation began on the site of dilapidated mountains. Thus, medium blocky-folded mountains were formed. Further, students, working with tectonic and physical maps, give examples of medium mountains (Cordillera, Verkhoyansk Range).

Rice. 5. Medium (blocky-folded and folded-blocky renewed) mountains.

Rice. 6. North Santiago. Cordillera

Young mountains are still being formed. Being young mountains, they do not bear signs of destruction. Basically, these are high mountains, they look like folds. Often their peaks are sharp, covered with snow caps. Vivid examples the youngest mountains are the Alps, the Himalayas, the Andes, the Caucasus, etc.

Fig.7. young mountains

Rice. 8. Caucasus. Dombay.

3. Internal and external forces of the Earth

Questions for students:

- Tell me, why does the oceanic crust turn into mountains? (the internal forces of the Earth act)

Why do mountains turn into plains? (external forces of the Earth act).

- So, what forces of the Earth influence the shape of the relief of our planet? (internal and external).

Since ancient times, granite has been the embodiment of durability and strength. Granite can equally be compared with a strong-willed, inflexible person, and indestructible, faithful friendship. However, even granite will crumble into small gravel, crumbs and sand if it experiences temperature changes, the influence of wind, the activity of living organisms and humans for a long time.

Temperature fluctuations. With the first rays of the sun, snow and ice begin to melt high in the mountains. Water penetrates into all cracks and depressions of rocks. At night, temperatures drop a few degrees below zero and the water turns to ice. At the same time, it increases in volume by 9% and pushes the cracks apart, expanding and deepening them. This continues day after day, year after year, until some crack separates a piece of rock from the main massif and it rolls down the slope. Rocks are also subjected to heating and cooling. The minerals they contain have different thermal conductivity. Expanding and contracting, they break strong bonds between themselves. When these bonds are completely destroyed, the rock turns into sand.

Rice. 10. The destruction of rocks in the mountains under the influence of temperature changes.

The active impact of plant and animal organisms on rocks causes biogenic weathering. The roots of plants perform mechanical destruction, and the acids released in the course of their vital activity perform chemical destruction. As a result of many years of activity of living organisms, coral reefs and a special type of islands arise - atolls formed by calcareous skeletons of marine animals.

Rice. 11. Coral atoll - the result of the activity of marine organisms

Rivers and the World Ocean also leave an imprint on the Earth's relief: the river forms the channel and the river valley, the waters of the ocean form coastline. Surface waters leave scars of ravines on the surface of hills and plains. Ice during its movement furrows the adjacent territories.

Fig.12.

Bryce Canyon in the USA, formed as a result of the activity of flowing waters

Rice. 13. Road in Abkhazia to Lake Ritsa, laid along the bottom of a mountain river gorge

Rice. 14. Sand and pebble beach in Crimea, formed as a result of wave activity

The absolute master of open spaces is the wind. Encountering obstacles on its way, it forms majestic hills - dunes and dunes. In the Sahara desert, some of them are up to 200-300 meters high. In the mountain ranges located in the desert, there is almost never loose material that fills the depressions and cracks. That is why aeolian landforms appear, reminiscent of towers, pillars and bizarre castles.

Rice. 15. The remains in the desert resemble fairy-tale castles.

Rice. 16. Sand dunes.

Rice. 17. Barkhan

Human economic activity also causes changes in the relief. Man extracts minerals, as a result of which quarries are formed, builds buildings, canals, makes embankments and fills up ravines. This is all a direct impact, but it can also be indirect, which is the creation of favorable conditions for relief-forming processes (plowing of slopes causes rapid growth of ravines).

Over time, it changes under the influence of various forces. Places where there were once great mountains are becoming plains, and in some areas there are volcanoes. Scientists are trying to explain why this is happening. And already a lot modern science known.

Reasons for transformations

The relief of the earth is one of the most interesting riddles nature and even history. Because of how the surface of our planet has changed, the life of mankind has also changed. Change occurs under the influence of internal and external forces.

Among all landforms, large and small ones stand out. The largest of them are the continents. It is believed that hundreds of centuries ago, when there was no man yet, our planet had a completely different look. Perhaps there was only one mainland, which eventually broke up into several parts. Then they split up again. And all the continents that exist now appeared.

Another major form was the oceanic depressions. It is believed that earlier there were also fewer oceans, but then there were more of them. Some scientists argue that after hundreds of years new ones will appear. Others say that the water will flood some parts of the land.

The relief of the planet has changed over the centuries. Even despite the fact that a person sometimes greatly harms nature, his activity is not capable of significantly changing the relief. This requires such powerful forces that only nature has. However, a person cannot not only radically transform the relief of the planet, but also stop the changes that nature itself produces. Despite the fact that science has made a big step forward, it is not yet possible to protect all people from earthquakes, volcanic eruptions and much more.

Basic information

The relief of the Earth and the main landforms attract the close attention of many scientists. Among the main varieties are mountains, highlands, shelves and plains.

The shelf is those parts of the earth's surface that are hidden under the water column. Very often they stretch along the coast. The shelf is that type of relief that is found only under water.

Uplands are isolated valleys and even range systems. Much of what is called mountains is actually highlands. For example, Pamir is not a mountain, as many people think. The Tien Shan is also a highland.

Mountains are the most grandiose landforms on the planet. They rise above the land by more than 600 meters. Their peaks are hidden behind the clouds. It happens that in warm countries you can see mountains, the peaks of which are covered with snow. The slopes are usually very steep, but some daredevils dare to climb them. Mountains can form chains.

The plains are stability. The inhabitants of the plains are the least likely to experience changes in relief. They almost do not know what earthquakes are, because such places are considered the most favorable for life. A real plain is the most flat earthly surface.

Internal and external forces

The influence of internal and external forces on the Earth's relief is grandiose. If you study how the surface of the planet has changed over several centuries, you can see how what seemed eternal disappears. It is being replaced by something new. External forces are not able to change the Earth's relief as much as internal ones. Both the first and the second are divided into several types.

internal forces

The internal forces that change the Earth's relief cannot be stopped. But in modern world scientists from different countries they try to predict when and where an earthquake will occur, where a volcanic eruption will occur.

Internal forces include earthquakes, movements, and volcanism.

As a result, all these processes lead to the emergence of new mountains and mountain ranges on land and at the bottom of the ocean. In addition, there are geysers, hot springs, chains of volcanoes, ledges, cracks, depressions, landslides, volcano cones and much more.

Outside forces

External forces are not capable of producing noticeable transformations. However, they should not be overlooked. The shaping of the Earth's relief includes the following: the work of the wind and flowing waters, weathering, the melting of glaciers and, of course, the work of people. Although man, as mentioned above, is not yet able to greatly change the face of the planet.

The work of external forces leads to the creation of hills and ravines, hollows, dunes and dunes, river valleys, rubble, sand and much more. Water can destroy even a great mountain very slowly. And those stones that are now easily found on the shore may turn out to be part of a mountain that was once great.

Planet Earth is a grandiose creation in which everything is thought out to the smallest detail. It has changed over the centuries. There have been cardinal transformations of the relief, and all this - under the influence of internal and external forces. In order to better understand the processes taking place on the planet, it is imperative to know about the life that it leads, not paying attention to man.