Rivers and their tributaries are the waterways of our planet. They carry excess water from land to the ocean and play an active role in the ongoing transformation of the Earth's topography.
The Amazon is the deepest river on Earth. Every second it carries about 200 thousand m³ of water into the Atlantic Ocean. It is fed by seventeen large tributaries, and the drainage basin area, which occupies almost the entire northern part of South America, is approximately 7 million km². The length of the Amazon is about 7000 km, the width is often more than 10 km. The river is navigable for 1600 km from the mouth.
River of Records
The Amazon is the central artery, from which tributaries branch off, which are themselves very large rivers. The origins of many of them are in the Andes (Rio Negro, Purus, Madeira). Others flow from the Brazilian Plateau, located in the south (Tapajos, Xingu), and a smaller part - from the north, from the Guiana Plateau. When a river merges with one or more tributaries, such as the Rio Negro, the volume of transported water increases so much that a kind of inland sea is formed.
The Amazon River flows on either side of the equator, in a region with a humid, hot climate that receives between 1,500 and 3,000 mm of rainfall per year. Watercourses from the slopes of the Andes, fed by snowmelt, are replenished with surface runoff waters, since the soils of the equatorial rain forests are not able to absorb the entire volume of precipitation. Watercourses merge with small rivers, and they carry their waters into the main artery. Flowing into the ocean, the Amazon reaches a width of 60 km at the mouth and forms an estuary with many islands.
Change in terrain
Flowing waters not only carry excess water from land to sea. On their way, they also modify the planet's topography, moderately or violently, smoothly or intermittently. This process involves huge volumes of transferred rocks, reaching hundreds of millions of tons annually. Even the calmest-looking rivers never cease their activity for a moment, transporting dissolved substances, such as calcium bicarbonate, washed out of collapsing limestones.
Water transports loose, unconsolidated material: sand, clay and soil. As a result, rivers often acquire a characteristic color. The water of some tributaries of the Amazon, such as the Rio Negro, appears dark due to the presence of iron oxides and organic matter. The waters of others abound in silt and appear whitish (Madeira). Downstream from the confluence with the Rio Negro, the waters of the Amazon flow for a long time in two immiscible multi-colored streams.
Hard way
Plain rivers of the equatorial belt transport only small suspended particles and are not able to effectively destroy the strong bedrock lining their bottom. Therefore, the beds of African rivers are replete with rapids and waterfalls that form where the rocks are especially resistant to erosion.
Erosion processes are most noticeable in mountainous areas where surface slopes are significant. The beds of mountain rivers are often strewn with large fragments of rocks, which, during periods of high water, move, slide, turn over and are crushed by friction against each other. When the watercourse enters the plain, all this debris is deposited in the form of fan-shaped accumulations - alluvial fans. When rivers flow into lakes, the same thing happens: a small delta is formed - the first stage in the formation of a lake basin.
Large scale work
Over many thousands of years, watercourses carve incised valleys, gorges and canyons into the rocks. Steep-sided valleys are usually formed in hard rock that water can only break down with the help of abrasive materials such as sand, gravel and pebbles. The rotational movement of water in whirlpools leads to the formation of natural depressions in the riverbed, called giant boilers.
In a similar way, rivers wash away steep banks and, widening the channel, create picturesque bends. However, for further expansion of river valleys, the intervention of other mechanisms of the erosion process is necessary. Weathering, fragmentation and landslides gradually smooth out the forms created by the watercourse.
Captive or free
Rivers flowing across vast alluvial plains are freer in choosing their channel configuration than rivers locked in narrow gorges. Lowland rivers often change path, randomly meandering (wandering) within the main direction, such as the Okavango River in Botswana.
Sometimes rivers change course even more abruptly. As a result of displacement of earth masses and changes in water level, rivers capture neighboring watercourses and direct them into their own channel. Thus, the Moselle River in France, which once flowed into the Meuse, has now become a tributary of the Meurthe River.
Deltas
River deltas are unstable structures, the continuous reconstruction of which is based both on the accumulation of sediments carried by rivers and on their removal by the advancing sea. But luck in the battle between sea and land always favors the sea.
The Nile delta region in Egypt, with an area of 24 thousand km2, is one of the most densely populated in the world, as is the delta of the legendary Ganges, which flows in India. People have settled in these low-lying, fertile areas for a long time. However, the boundary between the elements of water and land is changeable. Due to floods, rivers often change their courses. Old riverbeds, remaining higher, dry up, forming new lakes and swamps. Even where the sea has already retreated, areas of land are not protected from the invasion of water.
The origin of the word "delta" is closely related to the Nile. This name was given to the lower reaches of the Nile by Herodotus in the 5th century. BC e., since the mouth of the river is shaped like an inverted capital letter D of the Greek alphabet. Since then, this term has come to mean a lowland composed of river sediments at the mouth of a river flowing into the sea or lake. The Rhone even has two deltas: one, small, was formed when the river flows into Lake Geneva, the other, much larger, in the Camargue, when it flows into the Mediterranean Sea.
Deltas can have different shapes. Some rivers, such as the Mississippi, branch into several branches, so that their delta resembles a crow's foot, while others, such as the Ebro in Spain or the Po in Italy, form arcs. The diversity of delta forms is determined both by the creative work of the river and by the opposition of the sea, the currents of which either prevent sedimentation or help wash up sand spits, as happens in Venice. Thus, the movement of sediments of the Po River by the sea current led to the formation of a coastal bank in the northern part of the delta, cutting off the Venetian Lagoon from the sea. The study of displacements of the littoral zone shows that the shape of the coastline, river channels and their tributaries changes over several millennia. Archival documents allow us to trace the movements of the Rhone in the Camargue region and measure them in kilometers.
"Multiple" delta
A delta can be formed by several deltas located one after another, such as the Mississippi Delta. Having traveled a path of more than 6,000 km, the river deposits sediment in the Gulf of Mexico, the annual volume of which is about 20 tons. It is not surprising that the river transports so much material, since it collects water from more than a third of the United States and receives such large rivers as the Missouri, Arkansas, and Red Rivers. Over 5,000 years, six interlocking deltas formed at the mouth of the Mississippi, creating one in the shape of a crow's foot.
Quality of materials
To win the battle with the sea and form a delta, the river must deposit a huge volume of alluvium. The nature of the material being transferred is no less important. The Amazon basin is dominated by chemical weathering, so there is little sand and gravel. Although the river's annual solid flow is about 1.3 million tons per day, it is dominated by fine particles that are carried north by the coastal current. That is why, when it flows into the Atlantic Ocean, the Amazon forms a huge estuary, and not a delta. However, active deforestation in the region leads to the destruction of ground cover and contributes to erosion. This can change the composition of the transported material, the direction of the channel, the speed of the current and ultimately lead to the transformation of the estuary into a delta.
Although in other regions the volume and quality of sediment transport is sufficient to maintain the delta, the construction of dams and power plants on rivers and their tributaries can reduce sedimentation and lead to victory for the sea.
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Lithosphere and hazardous natural phenomena
Human life and health are largely related to the processes that occur in the lithosphere. People's economic activities also depend on them. A significant part of these processes occurs under the influence of natural forces and is spontaneous in nature.
Natural processes and natural phenomena are divided into two groups:
- Earthquakes and volcanism caused by the internal energy of the Earth;
- Landslides, mudflows, landslides, screes, which are a consequence of the forces of gravity.
Earthquakes are among the most dangerous and unpredictable natural phenomena. Within Russia, strong and frequent earthquakes are typical for Kamchatka, Sakhalin Island, and the Kuril Islands. The last devastating earthquake on Sakhalin Island occurred in $1995. The tragic result of the earthquake was the death of $2,000 residents and the destruction of the oil workers’ village of Neftegorsk. Such mountainous regions of Russia as the Caucasus, Altai, Sayan Mountains, the mountains of the Baikal region and Transbaikalia are also considered dangerous from the point of view of the possibility of earthquakes. In Russia, $40$% of the territory is considered seismically dangerous, including $20$% of mountainous areas.
Volcanic activity no less large-scale in its manifestations. All the country's volcanoes are concentrated in Kamchatka and the Kuril Islands. Of the $160$ volcanoes in Russia, $40$ volcanoes are located on the Kuril Islands. The active volcanoes of the Kamchatka-Kuril ridge are Karymskaya Sopka, Klyuchevskaya Sopka, Mutnovsky volcano, Shiveluch volcano, Kizimen, Bezymyanny, Berga, Sarycheva volcanoes. Columns of gases and volcanic dust rise into the atmosphere for $10$-$20$ km and gradually settle into the surrounding area.
Hot spots are associated with areas of volcanoes. springs and geysers. Hot underground water can be used to heat residential buildings and generate electrical energy. For example, in Kamchatka there is an experimental geothermal power plant - Pauzhetskaya.
Screes and landslides associated with mountainous areas where the terrain is very rugged. Destroyed rocks fall down under the influence of gravity, capturing new debris as they move. Most often, they are caused by the activity of flowing waters or tremors. In mountainous areas there are often sat down. This mixture of mud, clay, stone, formed during periods of prolonged rains and saturated the loose material of the mountain slopes, rapidly descends. A mudflow moves at a speed of several meters per second and on its way can demolish a dam, bridge, or village. They destroy crops and destroy roads. The Caucasus and Altai are more likely to encounter these phenomena than other mountainous regions.
There is also such a phenomenon as landslide. It is formed under the condition of alternation of water-bearing and water-resistant rocks. In this case, the upper layers slide down the slippery aquifer, forming a landslide. Landslides occur on the Volga and generally on steep, water-washed banks of rivers, lakes, and seas.
Direct human impact on the terrain
The terrain is formed not only by external and internal factors, but also by human economic activity. As a result of this activity, its anthropogenic forms are formed.
Definition 1
Anthropogenic relief is landforms modified or newly created by human activity.
The greatest impact on the relief is exerted by such activities as mining, laying roads, building underground structures and communications, and developing agriculture and forestry. As a result, there is a violation of the integrity of rocks and subsidence of the earth's surface and, as a consequence, the destruction of buildings and industrial structures. Anthropogenic earthquakes occur in a number of places - this is usually associated with the extraction of large amounts of minerals from the bowels of the earth. Such earthquakes can be observed in the Urals and in the south of Western Siberia. Mining leads to the appearance of quarries, mines, and waste heaps.
Definition 2
Terricons- These are dumps of waste rocks, reminiscent of low mountains.
Many spent industrial dumps are hazardous to human health. Most of these lands are located in the Kuznetsk coal basin, a number of regions of the Far East, Southern Siberia - these are those areas where open-pit mining takes place. Anthropogenic forms of relief arise both during the intake of artesian waters and during underground work. They can be sinkholes of sufficiently large depth and diameter. Such sinkholes are noted in Moscow, their depth reaches $4$ m, and the diameter is $40$ m. Similar sinkholes in Kuzbass reach a depth of $70$ m. Gully activity and soil erosion are an example of improper agricultural practices, when there is intensive plowing of the territory and natural vegetation is reduced.
Note 1
Human economic activity thus takes an active part and greatly changes the relief. Along with natural forms of relief, today there are artificial forms - these are structures, buildings, dams, bridges, tunnels. Multi-kilometer zones of continuous settlement have been formed. Artificial forms created by man change the surface of the earth, influence the climate and surface water flow.
Indirect human influence on the relief
A person can also influence the formation of relief in an indirect way. This consists in a deliberate or unplanned change in the conditions of morphogenesis, strengthening or slowing down the natural processes of denudation and accumulation. The result is increased soil erosion and anthropogenic gully formation. Drainage of swamps leads to changes in the topography of their surface. Excessive grazing and road degradation intensify deflation and revive the dynamics of accumulative sandy aeolian landforms. In areas of military operations, specific forms of microrelief and mesorelief arise - these are trenches and trenches, defensive ramparts, bomb craters.
Conscious and unconscious actions are taken under conditions of some kind of uncertainty, and any specific situation leads to risk in one form or another. Human action carried out at the boundary of the stability of a natural or natural-anthropogenic geomorphological system leads to geomorphological risk. Risk is generated by the presence and feeling of danger, which comes from any geomorphological object and is associated with the active actions and functioning of the subject of danger - man. To this end, environmental geomorphology develops a system of principles and methods that make it possible to identify dangerous geomorphological processes and objects and make a forecast of their development in order to reduce the degree and cost of risk.
Natural spontaneous natural processes are often technogenically predetermined. For example, deforestation in mountainous areas activates the formation of landslides and mudflows. Recently, fluvial-glacial and gravitational processes have been intensifying, which are formed as a result of the development of high-mountain meadows. The frequency of snow avalanches in high mountains is increasing, causing significant damage to the economy. Mountain roads, bridges, buildings, etc. fail. As a rule, phenomena dangerous from an environmental point of view arise suddenly. Experts, studying their emergence and development, have identified a number of important indicator factors that make it possible to make a forecast of the further course of their development. Their connection is visible not so much with natural or anthropogenic factors, but with the simultaneous influence and activity of the population in places that are susceptible to these phenomena.
Note 2
To predict the development of exogenous processes, the most effective are remote sensing methods, which increase the objectivity of the geographical forecast and improve the quality of the obtained material. And this already makes it possible to judge the nature and strength of exogenous processes in the near future.
Klestov Svyatoslav, Sadovnikov Danil 8b
2.
Relief is a set of irregularities in 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 that form the relief and related to them
natural phenomena.
3. Processes changing 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 earth's crust, its outpouring in the form of lava or
released to the surface during volcanic eruptions
Earthquakes –
These are tremors and vibrations of the earth's surface. According to modern
In our opinion, earthquakes reflect the process of geological transformation
planets.
Tectonic movements –
these are mechanical movements of 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 planet's active volcanoes. Here
there is a grandiose tectonic process of interaction between two large
lithospheric plates - Pacific and Sea of Okhotsk. At the same time, the earth's crust of the Pacific
ocean, more ancient and heavier, sinks (subducts) under the Sea of Okhotsk and,
melting at great depths, it gives rise to magma chambers that feed
volcanoes of Kamchatka and Kuril Islands.
About 30 active and more than 160 extinct volcanoes are now known in Kamchatka.
Most often, strong and catastrophic eruptions occurred in the Holocene (over the last 10
thousand years) occurred on two volcanoes - Avachinskaya Sopka and Shiveluch.
Klyuchevskaya Sopka volcano is the largest active volcano in Eurasia (4,688 m) -
known for its perfect, extraordinarily beautiful cone. First
the eruption of the 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
certain periods - annually, sometimes for several years, and
accompanied by explosions and ash falls.
5. Eruption of the Klyuchevskaya Sopka volcano
6. Earthquakes
In Russia, earthquakes occur in mountainous areas, at the junction
tectonic plates - the Caucasus, Altai, Western Siberia, Eastern Siberia, Kamchatka.
Most earthquakes in Russia occur in remote, sparsely populated areas
areas, but those earthquakes that occur in populated areas average 5-6
Once a century, many human lives are claimed, 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
islands, sometimes accompanied by tsunamis. Due to the earthquake in the Pacific Ocean
a tsunami formed off the coast of Kamchatka in 1952, which completely destroyed
city of Severo-Kurilsk.
Earthquakes occur due to the collision of lithospheric plates, as in the Caucasus
The Arabian Plate is moving north onto the Eurasian Plate. In Kamchatka
The Pacific plate collides with the Eurasian plate, also volcanic activity
is one of the causes of small tremors occurring in
in the immediate vicinity of the volcano or on it itself.
7. Neftegorsk earthquake (1995)
8. Tectonic movements of Russia
As a result of the long history of geological development on the territory of Russia,
main types of geotextures - flat-platform areas and large orogenic mobile
belts However, within the same geotextures, completely different
relief (low basement plains of Karelia and the Aldan Highlands on the shields of ancient platforms;
low Ural Mountains and high Altai within the Ural-Mongolian belt, etc.);
on the contrary, similar relief can form within different geotextures (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 quiescence at the beginning of the Cenozoic, when
low plains and practically no mountains 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 shallow sea waters
swimming pools. In the Oligocene, a new period of tectonic activation began - neotectonic
a stage that led to a radical restructuring of the relief.
The latest 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 the
formation and placement of morphostructures - large relief forms - across the territory of Russia,
arising as a result of the interaction of endogenous and exogenous processes with a leading role
first.
9.
Altai Mountains
English РусскийRules
What in the Ural cities involuntarily attracts the eye and attracts attention? From the streets of many of them our harsh mountains are visible. Many cities are surrounded by slender pine forests, and even cedar forests, the trees of which are directed upward, clouds are visible through their tops and the gaze involuntarily turns upward. Height and sublimity always attract and delight the soul of a sensitive person and does not leave him indifferent. And I know from myself, as a tourist, when you go to the mountains, joyfully overcoming a steep climb, the happiness that takes your breath away when you see open space, blue distances and mountain peaks around.
It is the height that captures and elevates our spirit.
Accurate Russian Language. No matter how difficult it was for a person before, everyone experiences delight. Everyone is amazed by the smell of clean mountain air and the special state of nature at altitude. If you stand in the mountains and your soul is calm, then you have amazing, pure, colorful dreams that are rarely seen below. A few days of communication with the nature of the mountains cleanse the soul and body, the smell of sweat changes, and an amazing feeling of purity appears.
After a few days, the mosquitoes stop bothering me. A feeling of health, security, and unity with Nature appears. You stop reacting painfully to cold, heat, and rain. You become part of them, they become part of you. Even when you come to the bathhouse after traveling, it seems that it is dirty and there is no need to wash. The supply of energy and impressions lasts for a long time, then they give a feeling of health and peace of mind.
If a person has a positive attitude towards the mountains, then he will definitely experience a state there similar to heartfelt prayer.
And those who pray and have experienced heartfelt admiration of the spirit will feel that it is easier and more joyful to pray in the mountains; many ideas and thoughts always come for creativity, for improving oneself. From experience, we know that our annual joint hike determines the mood of the next working year and how we overcome ourselves in it will be the same in life throughout the year.
I was lucky to walk through the Ural Mountains from Konzhakovsky Kamen to Otorten, to see their beauty and diversity.
This is the proud beauty of Konjac with its mysterious Job plateau, on which we saw many amazing phenomena - dancing whirlwinds, living fogs and stormy nights at the top, when lightning flashes around. We are sure that previously, as the highest mountain in our area, it was a place of worship and prayer for the surrounding peoples.
The elemental spirits of this mountain are accustomed to communicating with humans.
But, unfortunately, modern man has forgotten that he is their master, and now they often play evil games with people who are out of balance. This is evidenced by the statistics of missing people there.
Changes in the relief of the earth's crust under the influence of internal and external processes
Yes, the mountains are harsh, but their elements obey the will of a fearless person. Now this area is under threat of destruction; the unique Job Plateau was sold at auction for the development of dunites there. If they start, then you can go to Kachkanar and admire the results of the mining industry. We have a lot of this, of course. But is it really necessary to aim for the highest, the most beautiful?
This is the Olvinsky stone, the glades of which are filled with the smell of Maryina root, on top of which there is an amazing forest of stones.
This includes the Sennaya Mountains - sacred places of the Voguls and Mansi, where there is a lot of St. John's wort.
They say that the guardian spirits of these temples for a long time haunt the unreasonable person who took something there for himself.
This is the Kazan crystal stone; in general, there is a lot of crystal in the Ural Mountains. Fire in the stone and fire in us.
This is the Ural Range, where we saw many amazing sunrises and wonderful waterfalls, where we fought with the elements of a thunderstorm and fell into one of them, when lightning struck all around, we breathed ozone, and we were filled with a fiery feeling of freedom and victory.
These are the magical castles of the Belt Range, similar to the outposts of Svyatogor, it seems that the heroes have just left them and will soon return and protect, save our world.
Isn’t it you and me who are the guardians of these outposts now?
And the mysterious Khalatsyakhl, the Mountain of the Nine Dead, under which nine tourists of the Dyatlov group died, and on which there are nine rocks.
Wonderful Otorten with its beautiful lake, where Goose rested, and much, much more.
Always, if you are in balance, if you come to the mountains with a pure heart, amazing moments of communication with nature, admiration of the spirit, peace, sublimity, and love for the whole world await you.
These are our mountains, our wealth, our source of inspiration, a place where you can always get away from the hustle and bustle and spend wonderful moments in joyful heartfelt work.
In 2007, our experience was further developed.
Under Mount Serebryansky Stone, near the confluence of the Serebryanka and Lobva rivers, the Ural Magnet festival took place. Three days passed in the joint cordial communication of friends from both sides of the Ural Mountains and nature was with us, there were amazing sunny days. Mosquitoes virtually disappeared and, amazingly, there were almost no ticks, although
Test work 4 External and Internal Processes Forming Relief
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1. As a result of what natural processes did the formation of relief occur and occur on the territory of Russia?
Relief is a set of forms of the earth's surface, different in outline, size, origin, age and history of development. Relief influences the formation of climate, the nature and direction of river flows depend on it, and the distribution of flora and fauna is associated with it.
Relief significantly influences human life and economic activity.
Knowledge about their origin and development, the features of the geological structure and tectonic structures will help explain the patterns of placement of the main forms.
The territory of Russia was formed as a result of the gradual convergence and collision of individual large lithospheric plates and their fragments. The structure of lithospheric plates is heterogeneous. Within their boundaries there are relatively stable areas - platforms - and mobile folded belts. Mountains formed in mobile folded belts. These belts arose at different times in the marginal parts of lithospheric plates when they collided with each other.
Sometimes fold belts are found in the inner parts of a lithospheric plate. This is, for example, the Ural ridge.
External processes are associated with the activity of flowing waters, glaciers, etc. During the Quaternary period, due to changes in climatic conditions, several glaciations arose in many regions of the Earth. Central glaciations in Eurasia - Scandinavia, the Polar Urals, the Putarana plateau in the north of the Central Siberian Plateau and the Byrranga mountains on the Taimyr Peninsula.
As the glacier moved south, the Earth's surface changed greatly.
From the center of glaciation, stones (boulders) and loose sediments (sand, clay, crushed stone) moved along with the ice. On its way, the glacier smoothed out the rocks. In the southern regions it melted, depositing the material it brought with it.
These loose clay-boulder deposits are called moraine. Moraine-hilly-mud relief prevails on the Valdai and Smolensk-Moscow uplands of the Russian Plain. When the glacier melted, huge masses of water were formed, which transported and deposited sandy material, leveling the surface.
This is how water-glacial plains were created along the outskirts of the glacier. In the northern regions, melted glacial waters filled the depressions dug out by the glacier in the crystalline base.
This is how numerous lakes were formed in the north-west of the Russian Plain.
The land surface is constantly exposed to flowing waters - rivers, groundwater, temporary watercourses. Flowing waters dissected the surface, creating gorges, ravines, and hollows.
Where there is little precipitation, wind plays a leading role in changing the relief. Wind activity is especially evident in the Caspian lowland.
Where sands are widespread, the wind creates an aeolian relief with dunes, dunes, cellular sands, etc.
Summary of a lesson in geography on the topic “Changes in relief under the influence of internal processes”
2. Name the main mountain systems of Russia and the mineral resources associated with them.
The mountains of our country have different heights and lengths, different orientations and outlines, but they are all confined to folded areas.
In the extreme southwest, from the Black to the Caspian Seas, stretch the high Caucasus Mountains with pointed peaks and mountain glaciers.
The highest point of the Caucasus is Mount Elbrus.
To the southeast of the West Siberian Plain are the Altai and Sayan ranges. The Sayan Mountains are adjacent to a system of medium-high ridges and highlands of the Baikal region and Transbaikalia.
The easternmost of them, the Stanovoy Range, almost reaches the coast of the Sea of Okhotsk. All mountain structures from Altai to the Stanovoy Range are called the mountains of Southern Siberia.
To the east of the Central Siberian Plateau and the mountains of Southern Siberia are the mountain ranges and highlands of Northeastern Siberia and the Far East. The Verkhoyansk ridge stretches along the Lena coast in its lower reaches, and to the northeast of it is the Chersky ridge. Between them there is a system of plateaus: Yanskoye, Oymyakonskoye and others, separated by low mountains.
An almost continuous chain of highlands and ridges stretches along the Pacific coast from the Chukotka Plateau to the Sikhote-Alin. There are mountain ranges in Kamchatka and Sakhalin. The Kuril Islands are the peaks of an underwater volcanic ridge.
Only one mountain structure is located among the vast plains of the western part of the country. These are the medium-high Ural Mountains, stretching in a relatively narrow strip from north to south for more than 2000 km.
Deposits of iron (Western Sayan) and polymetallic ores (Eastern Transbaikalia), gold (highlands of Northern Transbaikalia), mercury (Altai), etc. are confined to ancient folded areas.
The Urals are especially rich in a variety of ore minerals, precious and semi-precious stones. There are deposits of iron and copper, chromium and nickel, platinum and gold.
Deposits of tin, tungsten and gold are concentrated in the mountains of North-Eastern Siberia and the Far East, and polymetallic ores are concentrated in the Caucasus.
What is the relief-forming activity of surface waters?
Surface water destroys rocks, eroding and dissolving them. Flowing waters - rivers, streams, temporary streams, moving along the earth's surface, erode it, destroy the rocks that make up the surface.
The products of destruction - pebbles, sand, silt - are transported and deposited by flowing waters. This process of destruction of rocks that make up the earth's surface is called erosion, and the process of deposition of destruction products by water is called accumulation.
Many landforms are formed mainly by the activity of flowing waters: river valleys, ravines, gullies and hollows.
4. In what regions of Russia does the activity of the internal forces of the Earth manifest itself?
The greatest activity of internal forces in Europe and Asia is confined to 2 zones - the Mediterranean and the Pacific. In Russia, the 1st zone includes the Caucasus, and the 2nd zone includes Sakhalin, Kamchatka and the Kuril Islands. All these areas are characterized by earthquakes, and most of them have volcanoes.
The latter are divided into active and extinct. Volcanoes that erupt from time to time and constantly release vapors and gases are called active, while volcanoes whose eruptions are not recorded in historical time are called extinct.
An example of an extinct volcano is Mount Elbrus in the Caucasus. Active volcanoes within Russia are found only in Kamchatka and the Kuril Islands.
5. What process is called weathering.
Weathering is the slow destruction of rocks due to temperature fluctuations, under the influence of moisture and plants.
The sun's rays heat the earth's surface unevenly. During the day, especially in desert and semi-desert areas, the surface becomes very hot and cools quickly at night. As a result, the minerals that make up the surface of rocks either expand or decrease in volume, which leads to the destruction of rocks.
The wind picks up small rock fragments and carries them to depressions. Surface waters, in turn, destroy rocks, eroding and dissolving them. All these processes of rock destruction are called weathering.
Option II
What forces influence the formation of relief.
The formation and development of relief forms are actively influenced by 2 groups of forces: one is the internal forces of the Earth, the main cause of which is due to the internal heat of our planet, the other is external forces arising under the influence of the thermal energy of the Sun.
The activity of internal forces is manifested primarily in the processes of mountain building and volcanism. This means that as a result of their activities, the main unevenness of the earth's surface arises - mountains and entire mountainous countries. These forces are the builders of the relief of the earth's surface.
The external forces of the Earth are caused by the thermal energy of the Sun.
The activities of these forces manifest themselves in a very diverse manner, but ultimately they all strive to level and smooth the relief through the destruction, transfer and redeposition of rocks, under the influence of wind, surface and underground waters, the movement of glaciers, etc.
2. What is the relief-forming role of surface water?
The activity of groundwater has a great influence on the formation of relief. This is most noticeable in areas where the surface layers of rocks are composed of soluble and permeable rocks (limestone, gypsum, dolomite, rock salt).
Here, precipitation waters, seeping through permeable surface layers, reach aquifer layers and accumulate above them in aquifers. Within aquifers, groundwater moves along cracks in rocks, partially dissolving them. As a result, underground voids - caves - are formed. Sometimes the roof of these caves collapses, and closed depressions are formed on the earth's surface - karst basins.
In addition, precipitation water flowing over the surface seeps into rock cracks and dissolves them. In this case, depressions are formed, often round in shape, which are called karst sinkholes.
3. What mineral resources are typical for the platforms?
On platforms, ore deposits are confined to the shields, or to those parts of the plates where the thickness of the sedimentary cover is small and the foundation comes close to the surface.
Iron ore basins are located here: the Kursk Magnetic Anomaly (KMA), deposits of South Yakutia (Aldan Shield).
However, the platforms are most characterized by fossils of sedimentary origin, concentrated in the rocks of the platform cover. These are predominantly non-metallic mineral resources. The leading role among them is played by fossil fuels: gas, oil, coal, oil shale.
They were formed from the remains of plants and animals accumulated in the coastal parts of shallow seas and in lake-marsh land conditions. These abundant organic remains could accumulate only in sufficiently humid and warm conditions favorable for the rapid development of vegetation. The largest coal basins in Russia are: Tungusky, Lensky and South Yakutsky - in Central Siberia, Kuznetsky and Kansko-Achinsky - in the regional parts of the mountains of Southern Siberia, Pechora and Podmoskovny - on the Russian Plain.
Oil and gas fields are concentrated in the Urals part of the Russian Plain from the Barents coast to the Caspian Sea, in the Ciscaucasia. But the largest oil reserves are in the depths of the central part of Western Siberia (Samotlor, etc.), gas - in its northern regions (Urengoy, Yamburg, etc.).
In hot, dry conditions, salt accumulation occurred in shallow seas and coastal lagoons.
There are large deposits of them in the Urals, in the Caspian region and in the southern part of Western Siberia.
4. How do glaciers influence the formation of relief.
The formation of the relief of the earth's surface is significantly influenced by the work of glaciers.
Ice, like water, moving along the surface, gradually destroys its irregularities.
Over time, the rock protrusions are smoothed out by the action of the glacier, their surface is polished, and they turn into dome-shaped hills, which are called “ram’s foreheads.”
Moving along the slopes, glaciers sometimes plow out quite deep hollows, expanding and deepening existing depressions.
For the relief of mountainous countries that were subject to glaciation, circuses or carts are typical, having the form of chair-shaped depressions located on the slopes of the mountains; on 3 sides the pits are limited by steep rocky walls and open on the 4th (towards the fall of the slope).
Due to weathering, the pits gradually increase in size laterally and in depth.
5. Which epochs are called metallogenic.
Epochs corresponding to geological cycles in the history of the Earth, during which certain groups of metal deposits (ferrous, non-ferrous, rare, etc.) arose.
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Geological processes of relief formation
From the moment of its formation to the present day, the earth’s crust has been 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 that arises in its depths.
Internal processes include: tectonic, igneous and metamorphic. Internal forces change the shape of the earth's surface: they create irregularities in the form of depressions and elevations and thereby give contrast to the relief.
Exogenous processes occur on the Earth's surface and at shallow depths in the earth's crust.
Sources of exogenous forces are solar energy, gravity and the vital activity of organisms. External forces tend to smooth out the unevenness created by internal forces; they give the earth's surface a more or less flat shape, destroying hills and filling depressions with destruction products.
Internal and external processes are united under a common name geological.
Endogenous processes of relief formation
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 occur constantly.
In some cases they are slow, barely noticeable to the human eye (eras of peace), in others - in the form of intense stormy processes (tectonic revolutions). Mountain building, earthquakes, and volcanism are associated with tectonic movements in the earth's crust. The shape, nature and intensity of destruction of the earth's surface, sedimentation, and 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, sedentary structures.
The platforms are characterized by leveled landforms. They consist of a hard, non-foldable section of the earth's crust (crystalline base).
They are characterized by calm, slow movements of a vertical nature.
Geosynclines- moving parts of the earth's crust. They are located between the platforms and are their movable connections. Geosynclines are characterized by various tectonic movements, seismic phenomena and volcanism.
Tectonic movements of the earth's crust are divided into three main interrelated types of movements:
- oscillatory;
- folded;
- explosive.
Oscillatory movements are movements in which, firstly, the direction of movement is vertical, and secondly, the direction of movement periodically changes (i.e.
that is, during oscillatory movements, one and the same section of the earth’s crust experiences alternate descent or rise). They do not cause sudden disturbances in the original occurrence of rocks.
Oscillatory movements occurred at all geological stages of the development of the earth's crust and are still occurring now.
At folded movements, 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 folding movements of the earth's crust.
At explosive movements, cracks appear. Tectonic ruptures are shear or detachment faults. Rupture movements contribute to the formation of ore veins and mineral springs, but they also complicate the development of mineral resources.
Oscillatory movements
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 is in a state of complete rest.
Oscillatory movements are expressed by slow (“secular”), uneven vertical uplifts 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 repeating wave-like process, that is, successive rises and falls do not cover the same areas, but each time they shift in space in a wave-like manner.
Changes over time and travel speed.
Within geosynclines it varies from a centimeter to several units of centimeters per year, and within platforms - from fractions of millimeters to 1.0 cm/year.
Oscillatory movements in both the first and second areas occur slowly, calmly, people and existing devices do not feel them. The presence of movements is established only by carefully studying their results.
Development areas slow oscillatory movements can be different. Sometimes they cover vast territories (tens and hundreds of thousands of square kilometers), and then uplifts lead to the appearance of large, but very gentle arches, and subsidence leads to the formation of similar depressions.
Large arches and depressions are called first order structures.
Movements that occur over smaller areas lead to the complication of first-order structures with second-order structures. In turn, third-order structures arise on second-order structures, etc.
Changing directions of vertical movements leads to changes in the outlines of sea basins, lakes, the direction of their geological activity, as well as the activity of other exogenous factors.
When the continent sinks, the sea sometimes covers large areas of land (transgression), and sometimes it only invades the river valleys (ingression).
When the continent rises, the sea regresses, the size of land is increasing.
Regressions are characterized by the vertical replacement of deep-sea sediments with shallow-water ones (clays are replaced by sands, sands by pebbles).
During transgression, the opposite picture occurs - the replacement of shallow-water sediments with deep-water ones.
On slow raising indicate marine terraces, which represent a coastal platform developed as a result of the work of the sea.
What processes influence the formation of relief?
The width of these terraces in Norway is measured in tens of meters. As a result of slow uplifts of the earth's crust, some ancient ports now found themselves at quite a considerable distance from the coast; the islands were connected by land bridges to the continent.
On dives individual sections of the earth's crust are indicated by coastal terraces flooded with water, the presence of underwater river valleys at the mouth of rivers (Amazon, Congo), flooded river mouths - 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 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 km2 in 100 years.
Subsidences are especially characteristic of the Netherlands (40–60 mm/year).
Residents protect the country from flooding with a complex system of dams and dams, and constantly monitor their safety. 2/3 of the Netherlands is below sea level.
In Russia, the areas of Kursk (3.6 mm/year), the Central Russian Upland (1.5–2 mm/year), Novaya Zemlya, and the Northern Caspian region are rising.
Subsidences occur 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.
5. Remember what the following concepts mean:relative and absolute height, watershed, river valley, terrace, interfluve, ravine, dune.
As you know, Chuvashia is located in the eastern part of the East European Plain. But the word “plain” defines only the general character of the surface of the republic. In fact, the relief of Chuvashia is complex and varied.
On our plain there are numerous elevated areas and depressions, river valleys, deep ravines, dune hills and swampy lowlands.
The main factor in the formation of the modern relief of Chuvashia is erosion processes resulting from water activity. On slopes and watersheds, it constantly washes away material and carries it to low places. The geological structure of the territory of the republic enhances the washout of material.
Rocks formed during the Permian period and exposed to the surface are crushed, contain aquifers and feed watercourses. In depressions, flowing water merges into streams, eroding the soil. Gullies appear, growing into ravines, and then into valleys of streams and rivers.
And in conditions of a general rise of the territory, the activity of flowing waters intensifies and significantly changes the appearance of our region. It was the activity of rivers that mainly shaped the modern relief of Chuvashia.
The Volga divides the territory of our republic into two parts, differing in size and nature of the relief: the low-lying left bank and the elevated right-bank.
On left bank The Volga, which makes up 3% of the territory of the republic, has formed terraces.
In relief they are represented by lowlands with heights of 80-100 m. On the terraces there are lumpy sands. The mounds are created by the action of the wind and represent dunes, which today are covered with forest. The low altitude and slight slope of the terrain against the backdrop of significant precipitation led to the formation of many peat swamps And lakes.
Modern relief right bank Chuvashia is represented by the northeastern part of the Volga Upland.
The hill was formed as a result of tectonic movements of the earth's crust during the Paleogene period. The highest point within Chuvashia is located in its southern part and reaches 286 m. In the rest of the hill, the relative height ranges from 150 to 250 m.
On the entire surface of the hill, wide interfluves, cut by ravines and gullies, alternate with deeply incised valleys.
Changes in relief under the influence of internal processes
In the eastern part of Chuvashia there are 2.3 times more gullies and 1.4 times more ravines than in the western part. But the northeastern part of Chuvashia has the greatest density of ravines, since there are few forests and the lands are heavily plowed. The density of the river network in the northern half of the republic is higher than in the southern half. In the southwestern part of Chuvashia, the girder network is denser and is five times larger than the ravine network.
The ravines and gullies have an asymmetrical shape: the northern and eastern slopes are elongated and gentle, while the southern and western slopes are steep.
This is due to uneven heating by the sun and uneven accumulation of snow on the surface, so material is washed off the slopes at different rates. Due to the extremely dense network of ravines and gullies characteristic of our republic, it is often called the country of ravines. Most of the lands on the right bank of the republic are plowed and occupied by cultivated plants. But ravines cause great harm to our fields, and we have to constantly fight them.
On the steep slopes of river valleys and large ravines of the republic, landslides.
Such slopes are distinguished by stepped ledges. The trees on these slopes are inclined in different directions. Landslides can be found on the right bank of the Volga, on the steep left bank of the Sura near Alatyr and in the valleys of other rivers of Chuvashia. They develop because the slopes are composed of layered strata, where waterproof layers alternate with permeable ones. With prolonged moisture, for example, in spring or rainy autumn, the layers become unstable and huge masses of soil slide down the slope.
Landslides, like ravines, cause enormous damage to the economy of the republic. They destroy buildings and structures located on the slopes and destroy arable land.
Watersheds in Chuvashia are most often very smooth.
But in some areas, where the heights exceed 200 m, there are low hills. This remnants more ancient surface, preserved in the form of islands.
They are found in Alatyrsky, Vurnarsky, Kozlovsky, Morgaushsky, Urmarsky, Poretsky and Yalchiksky districts.
In the southwestern part of the republic, especially in the Sura basin, the interfluves are represented by sandy dunes, overgrown with forest. Depressions between dunes swampy.
Thus, we are convinced that the relief of Chuvashia is really complex, the gully-beam nature of the relief dominates.
The following circumstances contribute to the development of the gully-beam network in the republic:
1) deeply dissected relief (its relative height exceeds 200 m);
2) sedimentary rocks underlying the Quaternary cover are represented by layers that are weakly resistant to erosion (silts, clays, limestones, sands, etc.);
3) the flow of permanent and temporary watercourses throughout the year is uneven (for example, the flow of Tsivil in April is 75-80% of the annual amount);
4) low forest coverage of the republic (only 31% is covered with forests);
5) a general rise in the territory of the republic;
6) high agricultural development of land, especially in the northern part of the republic (agricultural lands of the republic occupy 55% of its total area).
Therefore, it is necessary to constantly combat water erosion, weakening the effect of the listed causes.
commit?
Rep. 1:
Relief is formed mainly as a result of long-term simultaneous effects on the earth's surface of endogenous (internal) and exogenous (external) processes.
Relief is studied by geomorphology.
Rep.
Dependence of relief on external geological processes
2:
Relief is formed mainly as a result of long-term simultaneous effects on the earth's surface of endogenous (internal) and exogenous (external) processes. Relief is studied by geomorphology.
Endogenous processes are relief-forming processes that occur mainly in the bowels of the Earth and are caused by its internal energy, gravity and forces arising during the rotation of the Earth.
Endogenous processes manifest themselves in the form of tectonic movements, magmatism, the activity of mud volcanoes, etc.
Endogenous processes play a major role in the formation of large landforms.
Exogenous processes are relief-forming processes occurring on the Earth’s surface and in the uppermost parts of the earth’s crust: weathering, erosion, denudation, abrasion, glacial activity, etc.
Exogenous processes are caused mainly by the energy of solar radiation, gravity and the vital activity of organisms.
Exogenous processes predominantly form meso and microrelief forms.
Geography is a science that studies the geographical envelope of the earth, and it is also the science of the earth's topography. Relief is the constantly changing shape of the earth's surface or a set of irregularities in the earth's surface that differ in origin, size and age. Over millions of years of the Earth's history, under the influence of various forces, plains appeared where mountains stood, and where there were plains, high active volcanoes arose.
There is a direct relationship between the topography of the earth and the structure of the lithosphere. Thus, mountains were formed at the junctions of lithospheric plates, and plains were formed in the centers of the plates.
Landforms or morphostructures
There are such large and small landforms as
- continents– the largest forms; scientists believe that there was once only one continent, the gradual division of which led to the modern appearance of the Earth;
- oceanic trenches– also a large form of earth’s relief, formed due to the movement of lithospheric plates; it is believed that once there were fewer oceans on earth, and after hundreds of thousands of years the situation will change again, perhaps some parts of the land will be flooded with water;
- mountains– the most grandiose forms of the earth’s relief, reaching enormous heights; mountains can form chains of mountains;
- highlands– isolated mountains and ridge systems, such as the Pamirs or Tien Shan;
- shelves– areas of land completely hidden under water;
- plains– the most flat earth’s surface, the best place for human life.
Fig 1. Relief of the Earth
Such forms have a specific name - morphostructures. Scientists distinguish between such types of morphostructures as planetary and regional, which formed later. Tectonic movements took part in their development, and against their background there were movements of the upper horizons of the lithosphere.
Reasons for transformation of the earth's surface
Changes in the Earth's topography occur for various reasons. Transformation can occur under the influence of both internal and external forces.
External forces do not affect the earth's topography as much as internal forces.
Inner forces
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Internal forces include:
- earthquakes;
- movements of the earth's crust (tectonic movements);
- volcanism.
These processes lead to the appearance of:
- mountains and mountain ranges (both on land and at the bottom of seas and oceans);
- chains of volcanoes;
- geysers and hot springs;
- ledges;
- cracks;
- depressions and much more.
External forces
External forces include:
- weathering:
- the power of flowing water;
- underground water power
- melting glaciers;
- active transformative activity of people.
Naturally, external forces are not capable of producing global changes in the earth's topography. But long-term exposure to one factor or another leads to transformation. Gradually appear
- hills, ravines, basins, dunes and dunes, river valleys (all this refers to flat landforms);
- screes, gorges and rocks of bizarre shapes (all this refers to mountainous landforms). It is interesting that external forces, acting gradually over a long period of time, can also lead to global destruction. So water is quite capable of destroying an entire mountain.
It must be remembered that the relief is also influenced by such external processes as:
- circulation of water in the atmosphere;
- movement of air masses;
- change of vegetation cover;
- animal migration.
More detailed information is presented in the table of external forces changing the topography of the earth's surface (it can be used in geography lessons in 7th grade).
| Process | Example | Manifestation in relief | Essence of the process |
| Weathering |  Figure 2. Weathering |
scree formation | |
| Wind power |  Fig 3. Wind force |
formation of barchans and dunes | transport of rocks and loose sediments |
| The power of water |  Fig 4. The power of water |
rock destruction | transfer and erosion of rocks |
| Melting glaciers |  Figure 5. Melting glaciers |
changes in continental outlines | increase in the volume of water in the World Ocean |
Internal forces usually create various forms of earth's relief, and external forces destroy them.
Relief age
The time that has passed since the formation of the modern appearance of the Earth is called the age of the relief. It could be years, hundreds, thousands, millions of years. The age of large relief forms can range from 200 to 90 million years. In addition to age, there are also numerical characteristics of the relief surface.
What have we learned?
The Earth's topography is characterized by great diversity, complexity and incredible morphostructures. Why is the topography of the earth so varied? There are large and small irregularities that arise under the influence of internal and external forces. Transformation and change occur slowly, gradually; one human life is not enough to notice all the changes that have occurred. The earth’s surface seems to be breathing, sometimes falling, sometimes rising, and sometimes simply bursting from the stress that has arisen. Thus, the development of the Earth's topography continues to this day.
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However, changes in landforms are actively occurring today. The relief-forming factors that are characteristic of the territory of Russia today can be divided into two groups: exogenous (wind and water activity) and endogenous (movements in the lithosphere).
Modern relief-forming processes can be divided into two groups: internal (endogenous), caused by movements of the earth's crust (they are called neotectonic or recent), and external (exogenous).
Development of relief forms in Russia
The development of Russian relief forms dates back to the Quaternary period, when, due to climate change, many areas of our planet were covered with glaciers. Thus, the centers of glaciation became the modern Ural Mountains, the Taimyr Peninsula and the Central Siberian Plateau.
Over time, glaciers began to move south, moving sand, rubble and clay with them. High temperatures in the southern territories contributed to the rapid melting of ice, which led to the settling of loose rocks on the soil and the formation of moraine relief.
This type of relief prevails in the Moscow and Smolensk regions. Regular climate changes on the planet have caused the northern glaciers to melt.
Glacial waters filled depressions in crystalline rocks, thus creating lakes in the northern part of the Russian Plain.
Human activity and formation of relief
In the course of industrial development, irreparable changes in the relief of Russia occur. The types of human activities that affect the relief include: mining, construction of highways and railways, moving soil for agricultural purposes.
Very often, human intervention in the relief structure causes such negative consequences as the appearance of natural disasters.
The influence of wind on the development of relief
In regions of the Russian Federation that are characterized by large amounts of precipitation, the formation of the relief is influenced by the wind.
In particular, the special influence of wind on the formation of relief is typical for such territories as the Caspian lowland and the coast of the Baltic Sea (Kaliningrad region).
Natural phenomena
Natural natural phenomena are phenomena that occur in the balls of the lithosphere. Natural disasters include landslides, earthquakes, avalanches, and volcanic eruptions.
The most typical event for Russia is an earthquake. So in 1995, the Sakhalin Peninsula suffered from a strong earthquake. Strong internal tremors led to the destruction of several settlements.
Mountainous regions, in particular the region of the Ural and Altai Mountains, are characterized by landslides and landslides. Due to the fact that these mountain systems belong to old mountains, the masses of snow that melt in the spring carry with them fragments of stones, which is dangerous for local residents.
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