Every schoolchild knows that there are mountains, plains, plateaus, canyons, caves, deserts, hills and valleys on our planet, which are collectively called...

Why the Earth's topography is very diverse: main factors, examples

From Masterweb

06.09.2018 02:00

Every schoolchild knows that there are mountains, plains, plateaus, canyons, caves, deserts, hills and valleys on our planet, which are collectively called the word “relief”. The question of why the Earth's topography is very diverse is discussed in this article.

What is meant by the word "relief"?

Our planet has three important components: lithosphere, atmosphere and hydrosphere. Before examining the question for 7th grade schoolchildren, why the Earth’s topography is so diverse, it is necessary to define this concept.

So, the word “relief” means the totality of forms of the upper part of the lithosphere of our planet ( earth's crust), which are both found on land and form the bottom of oceans and seas. The branch of geology that studies all these forms is called the science of geomorphology. The main object of its study is the surface of continents and islands. However, it also studies the seabed with its seamounts, plains and depressions.

What types of terrain are there?

Considering the question of why the Earth's topography is so diverse, we should say a few words about what it is like.

First of all, this is macrorelief, that is, huge areas on the surface of the planet that have a certain characteristic. The following types are distinguished here:

• Plains. Vast areas of the planet's surface, which are characterized by small differences in height (several tens of meters). Plains, as a rule, are located low above sea level (up to 200 m). An example is the East European Plain, which is also called the Russian Plain.
• Mountains. When asked why the Earth's topography is so diverse, most people think about mountains. They are areas of land and ocean floor that rise to a great height (several kilometers) relative to the surrounding area. An example of this type of relief is the Caucasus Mountains or the Himalayas.
• Plateau. These are also huge expanses of earth that have undulating topography. They are located at altitudes of about 1000 m above sea level and often separate mountain ranges. Plateaus are formed by rocks, this fact distinguishes them from plains, which, as a rule, are of sedimentary origin. A striking example of this type of macrorelief is the Central Siberian Plateau.

There is also the concept of “relief of a given area,” which implies the presence in the area under consideration of depressions, ravines, canyons, valleys, beaches, hills, hills, and so on.

Why is the Earth's topography so diverse?

So, the main types of relief observed on our planet were briefly listed above. But why do there exist plains, mountain ranges and ridges, why is certain terrain cut by ravines, while others are smooth and have no hills?

Briefly answering why the Earth's topography is very diverse, it should be said that this fact is associated with the result of the action of internal (endogenous) and external (exogenous) processes.

Endogenous processes include processes that occur inside the Blue Planet, that is, these are movements of magma and displacements of lithospheric plates, which manifest themselves on the surface in the form of volcanic eruptions and earthquakes. This is the most powerful source of relief formation, which largely determined the appearance of our planet.

Exogenous processes are usually divided into three types:

• atmospheric;
• hydrosphere;
• biosphere.

The influence of the atmosphere on the relief includes the effect of wind and changes in daily temperatures. Both processes are destructive or erosive in nature. A striking example of the influence of wind on the terrain is the movement of sand dunes in deserts.

Hydrospheric, that is, caused by the action of water. There are many examples here: the appearance of ravines during the flow of rivers, the formation of alluvial deposits, modification of the coastline due to the influence of seas and oceans, the formation and movement of glaciers over the land surface, and others.

What is relief? The surface of the earth's crust is uneven. In some parts of it there are mountains or plains, in others there are deep ocean depressions. It is thanks to such irregularities that land and life exist on Earth. If the planet's surface were flat, it would be covered by an ocean 2450 m deep!

All irregularities in the surface of the land and the bottom of the seas and oceans are called relief.

Landforms. Any unevenness on the Earth's surface is a landform that has a height, area and outline. Convex relief forms are mountains, hills, hills on land and the bottom of the oceans, concave forms are basins of seas and lakes, ravines, ravines.

The largest landforms are continents and ocean basins; their existence is associated with the structure of the earth's crust. The largest forms also include mountains and plains. Large forms are ridges and depressions in the mountains, lowlands and hills on the plains. Medium and small forms are represented by ravines, hills, hummocks, mounds and other irregularities.

The relief of the Earth's surface is very complex, since smaller forms are superimposed in different combinations on larger ones. This is how the peculiar and unique appearance of the surface of every corner of our planet arises.

Reasons for the diversity of relief. The relief is very diverse, because the surface of the Earth is simultaneously affected by internal (deep) and external forces. Energy source internal forces- heat generated in the bowels of the planet, and external - solar energy.

Internal forces lower and raise, stretch and compress the surface, and crush rocks into folds. These forces give rise to the largest and many major landforms. Among the internal forces of the Earth, the most important role is played by slow movements of the earth's crust, earthquakes and volcanism. External forces - water, wind, glaciers, humans - create medium and small unevenness in the relief. All forms - both large and small - change their shape over time. Therefore, any physical map is only a snapshot of an ever-changing terrain.

Relief plays a huge role in shaping the nature of various regions of the Earth. It affects temperature, amount of moisture, vegetation and animal world. It also affects human life. People settle mainly on the plains because they are easier to farm on.

How the relief is depicted on plans and maps. Plans and physical maps can be used to describe the terrain in detail. For this purpose, there are height and depth marks on them. These marks show the height or depth of points on the earth's surface in relation to the level of the World Ocean. It is the same everywhere, since all seas and oceans communicate with each other. The ocean (or sea) level is taken as 0 m.

The height of a point above ocean (sea) level is called absolute height.

Markings of heights and depths are indicated by dots with a number next to them. It shows the height or depth in meters.

The absolute height of Moscow is 120 m, and St. Petersburg is 3 m. This means that the territory in which Moscow is located is located 120 m above sea level, and St. Petersburg - 3 m. Some points on the land surface are below sea level seas. In this case, a “-” sign is placed before the height mark. For example, -405, -28.

Using the physical map in the atlas, determine the absolute height of Mount Qomolungma (Everest) in the Himalayas.

Another way to depict the terrain is using contour lines.

Contour lines are lines on plans and maps that connect points with the same absolute height.

Horizontal lines and their absolute height are painted in brown (Fig. 45, a). Horizontal lines have short strokes - berg strokes. They are always directed down the slope. In places where the horizontal lines come closer together, the slopes are steeper.

The height of points on the earth's surface can be determined not only in relation to sea level, but also in relation to each other.

Rice. 45. Relief image: a - horizontal; b - horizontal lines with layer-by-layer coloring

Look at the drawing. Find the contour lines and determine which shape - convex or concave - is depicted on the map. Which slopes of this form are steeper and which are gentler?

The height of one point on a surface relative to another is called relative height.

If the top of a hill rises 150 m above sea level and 20 m above the surrounding plain, then 150 m is the absolute height of the hill, and 20 m is its relative height.

Rice. 46. ​​Absolute and relative height of the hill

Look at the picture and calculate the relative height of the hill.

A visual representation of the relief on physical maps gives layer-by-layer coloring (Fig. 45, b). It emphasizes relief steps with different absolute heights and depths. Between horizontal lines 0 m (sea level) and 200 m the land is colored green. Areas with heights of more than 200 m are painted with different shades of brown paint - the higher, the darker. In the same way, only in blue and dark blue, the depths of the seas and oceans are indicated. Layer-by-layer coloring is deciphered by a special scale of heights and depths, which is available on any physical map.

Questions and tasks

1. How are landforms classified by size? Give examples.
2. What is absolute and relative height?
3. Why is the relief on Earth so diverse?
4. Using the altitude and depth scale, determine which altitudes are dominant in Africa and which depths are dominant in the Pacific Ocean.

September 25, 2015

There are two main factors that influence the formation of different surface shapes, say, on different sides of the earth's crust. Thus, many influences were shared, which explain why the Earth's topography is so diverse. But first, let’s figure out what the concept of “relief” entails.

The term "relief" and its meaning

This word is of French origin, or some sources explain it by translating it according to the classics from Latin, and it is used for several industries - construction, art. But in all senses its meaning is the same - it is a collection of irregularities. For sculpture, these irregularities are created artificially by man; in construction, too, the human hand makes efforts to create one form or another. But on a planetary scale, man occupies the third place of honor among the forces influencing why the Earth’s topography is very diverse.

Groups of reliefs, or what categories do certain formations belong to?

First, let's remember what forms there are on the earth's surface. All types of land relief are divided into positive and negative. Positive include any elevation above the imaginary horizontal plane, negative - on the contrary, under it. That is, the first group includes mountains, hills, mounds, and plateaus. The second group includes depressions, crevices, valleys, and beams. And now let’s learn more about the diversity of the Earth’s topography, namely what creates it.

First place - the internal forces of the earth

These forces have a scientific name - endogenous. What is their impact?

Initially, the relief of the entire surface of the Earth was subjected to intense influence of internal forces. Earthquakes and volcanic eruptions are their most obvious manifestations, which, if you carefully study the research of anthropologists, previously very intensively changed the landscapes of the Earth, and even now quite often expose the earth’s crust to collapse, and, consequently, to new formation of the surface.
In addition, lithospheric plates are in constant slow motion, which also affects the creation of relief. Why is the Earth's topography varied in terms of internal forces? Because in connection with all the processes under the earth’s crust, changes occur outside. This is how mountains, ocean basins, plains and hills appear. Lithospheric plates(seven large and dozens of small ones) move, collide, move apart, forming the highest mountains (Alps, Himalayas, etc.) or deep depressions on land and under water (the Mariana Trench is the most striking example).

What we are seeing now is the result of the movement of plates over many millions or even billions of years, adjusted by the following type of influence on the relief.

Second place - external forces of the earth

The scientific name for these forces is exogenous. Why is the Earth's topography so varied due to these influences?

The sun, wind, precipitation - all these everyday phenomena are directly related to the formation of one form or another of the surface. All formations that arose under the influence of internal forces begin to transform because of them. So, the sun heats the mountain peaks. Substances and minerals that are present in the mountains have different thermal conductivities and other physical properties. As a result, expanding unevenly, they lose strong connections with each other, stratifying, dismembering and, ultimately, turning into sand. And if we add to this the influence of water, which in warm times penetrates into all the smallest cracks, and when the temperature drops turns into ice, which, accordingly, expands and pushes the cracks apart, aggravating them, this ultimately leads to the same destruction. That is why the Earth's topography is very diverse, because these processes occur every minute throughout the Earth.

We should not forget about the effect of rivers, lakes, and oceans on the areas adjacent to them. Thus, coastlines can either increase or decrease every year, depending on the direction of the waters. This may happen subtly, but it still happens.

Third place - man

He is considered to be external forces, but I would like to highlight this influence in a separate category. The development of technology gives a person an equal opportunity to go into space and climb deep into the earth’s crust (the main thing is that the funding is good, space is still winning here). The extraction of resources (oil, gas, ores, rock salt, and other minerals) is increasingly changing the once familiar landscapes. Draining of swamps, deforestation, creation of reservoirs, and other influences on the diversity of the Earth's topography can change the microclimate of certain areas, forcing animals to look for completely different habitats. And this happens everywhere, and this influence cannot always be called useful. If in the case of wind it is impossible to hold him accountable - this is an element, then a person, like sentient being, it would seem, should understand the destructiveness of his actions and make reasonable decisions. It would seem that.

And what's the end result?

As a result, it turns out that the modern topography of the Earth is the result of the interaction of all these forces, and they continue to act every day, continuously, and even right now, while your eyes are reading this long phrase, slowly but surely changing the outlines of our planet. And perhaps, several hundred years later, descendants will be very surprised to find an old relief map, for example, for 1995, of what the world was like at that time.

There are two main factors that influence the formation of different surface shapes, say, on different sides of the earth's crust. Thus, the many influences that explain are divided, very diverse. But first, let’s figure out what the concept of “relief” entails.

The term "relief" and its meaning

This word is of French origin, or some sources explain it by translating it according to the classics from Latin, and it is used for several industries - construction, art. But in all senses its meaning is the same - it is a collection of irregularities. For sculpture, these irregularities are created artificially by man; in construction, too, the human hand makes efforts to create one form or another. But on a planetary scale, man occupies the third place of honor among the forces influencing why the Earth’s topography is very diverse.

Groups of reliefs, or what categories do certain formations belong to?

First, let's remember what forms there are on the earth's surface. All types of land relief are divided into positive and negative. Positive elevations include any elevations above an imaginary horizontal plane, negative elevations, on the contrary, below it. That is, the first group includes mountains, hills, mounds, and plateaus. The second group includes depressions, crevices, valleys, and beams. And now let’s learn more about the diversity of the Earth’s topography, namely what creates it.

First place - the internal forces of the earth

These forces have a scientific name - endogenous. What is their impact?

Initially, the relief of the entire surface of the Earth was subjected to intense influence of internal forces. Earthquakes and volcanic eruptions are their most obvious manifestations, which, if you carefully study the research of anthropologists, previously very intensively changed the landscapes of the Earth, and even now quite often expose the earth’s crust to collapse, and, consequently, to new formation of the surface.
In addition, they are in constant slow motion, which also affects the creation of relief. Why is the Earth's topography varied in terms of internal forces? Because in connection with all the processes under the earth’s crust, changes occur outside. This is how mountains, ocean basins, plains and hills appear. Lithospheric plates (seven large and dozens of small ones) move, collide, move apart, forming the highest mountains (Alps, Himalayas, etc.) or deep depressions on land and under water (the Mariana Trench is the most striking example).

What we are seeing now is the result of the movement of plates over many millions or even billions of years, adjusted by the following type of influence on the relief.

Second place - external forces of the earth

The scientific name for these forces is exogenous. Why is the Earth's topography so varied due to these influences?

The sun, wind, precipitation - all these everyday phenomena are directly related to the formation of one form or another of the surface. All formations that arose under the influence of internal forces begin to transform because of them. So, the sun heats the mountain peaks. Substances and minerals that are present in the mountains have different thermal conductivities and other physical properties. As a result, expanding unevenly, they lose strong connections with each other, stratifying, dismembering and, ultimately, turning into sand. And if we add to this the influence of water, which in warm times penetrates into all the smallest cracks, and when the temperature drops turns into ice, which, accordingly, expands and pushes the cracks apart, aggravating them, this ultimately leads to the same destruction. That is why the Earth's topography is very diverse, because these processes occur every minute throughout the Earth.

We should not forget about the effect of rivers, lakes, and oceans on the areas adjacent to them. Thus, coastlines can either increase or decrease every year, depending on the direction of the waters. This may happen subtly, but it still happens.

Third place - man

It is classified as an external force, but I would like to highlight this influence in a separate category. The development of technology gives a person an equal opportunity to go into space and climb deep into the earth’s crust (the main thing is that the funding is good, space is still winning here). The extraction of resources (oil, gas, ores, rock salt, and other minerals) is increasingly changing the once familiar landscapes. Draining of swamps, deforestation, creation of reservoirs, and other influences on the diversity of the Earth's topography can change the microclimate of certain areas, forcing animals to look for completely different habitats. And this happens everywhere, and this influence cannot always be called useful. If in the case of wind it is impossible to hold him accountable - it is an element of nature, then a person, as a rational being, it would seem, should understand the destructiveness of his actions and make reasonable decisions. It would seem that.

And what's the end result?

As a result, it turns out that the modern topography of the Earth is the result of the interaction of all these forces, and they continue to act every day, continuously, and even right now, while your eyes are reading this long phrase, slowly but surely changing the outlines of our planet. And perhaps, several hundred years later, descendants will be very surprised to find an old relief map, for example, for 1995, of what the world was like at that time.

Attention, TODAY only!

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The main reason for such diversity is the mutual influence of internal (endogenous) and external (exogenous) processes on the surface of the planet. In turn, the catalyst for these processes is ultimately the energy of the Sun.

The essence endogenous processes consists of movements of the earth's crust, which can be either vertical or horizontal. These movements not only change the overall structure of the earth's crust, but also create new landforms.

While endogenous processes shape the planet’s topography (act as builders), exogenous processes sharpen and decorate it, being some kind of “sculptors” earthly forms. They influence the Earth's surface from the outside, through the weathering of rocks, the work of surface and groundwater, wind and gravity. It is important to note that these processes have occurred and are occurring on our planet constantly.

Denudation and accumulation are the main processes of relief formation

Now that you already know why the Earth's topography is very diverse, you can describe in more detail the processes that are to blame for this. We will talk about denudation and accumulation, which are connected dialectically.

Denudation is understood as the totality of all processes that are aimed at the destruction of rocks. The main driving force for denudation is gravity (force universal gravity). Mountain falls, mudflows, the movement of large glaciers and the flow of rivers - all this, one way or another, is connected with it. Denudation seeks to level out the terrain of the territory as much as possible.

Accumulation is the opposite process, which consists of the accumulation of rock particles on certain areas of the Earth's surface. Nevertheless, denudation and accumulation are closely and inextricably linked. As a result of accumulation processes, plains, terraces, deltas, dunes, coastal spits, and the like are formed on the surface of the Earth.

Genetic types of landforms

As a result of endogenous processes, the following types of relief are formed:

• tectonic;
• volcanic.

Among the main types of relief of exogenous origin (genesis) the following should be highlighted:

• fluvial relief (river valleys, ravines, ravines, gullies, etc.);
• glacial (eskers, moraine ridges and plains, kama, “ram’s foreheads”, etc.);
• coastal or abrasive (marches, spits, abrasive banks, beaches, etc.);
• gravitational (landslides, landslides, screes);
• aeolian (barchans, dunes);
• karst (caves, sinkholes, karst mines);
• suffosion (pods, “steppe saucers”);
• anthropogenic (relief created human activity: quarries, mines, embankments, waste heaps, dams, etc.).

All these numerous forms of relief create that motley and unique pattern of our planet.

Finally

After reading our article, the question of why the Earth’s topography is very diverse will no longer drive you into a dead end. The appearance, the design of our planet, was created over millions of years. The formation of the main forms of the earth's relief is based on various processes, such as endogenous (internal) and exogenous (external).