Land relief diagram. Relief of the earth's surface. Mountains. Plains. The most important landforms

As we already know, the earth's crust is mobile.

And this movement is determined by the movement of the mantle substance. As a result of such movement, mountains, ocean basins, and island arcs appear in the most mobile parts of the earth's crust. Stable areas of the earth's crust are characterized by flat surfaces. We call all this the relief of the Earth.
Continents and oceans- the main, largest landforms of the Earth. Their formation is due to tectonic, cosmic and planetary processes.
The mainland (continent) is the largest massif of the earth's crust, which has a three-layer structure: a sedimentary layer, a “granite” layer and a “basalt” layer. The average thickness of the continental crust is 35-45 km. Most of the continent's surface protrudes above the level of the World Ocean. In the modern geological era, there are six continents: Eurasia, Africa, North America, South America, Australia, Antarctica.
The world ocean is a continuous body of water surrounding the continents. The world's oceans are divided by continents into four oceans: the Pacific, Atlantic, Indian and Arctic. Land accounts for only 29% of the Earth's area. Everything else is the World Ocean.
Mountains and plains, as well as continents and oceans, are the main landforms of the Earth. Mountains are formed as a result of tectonic processes in zones of active tectonic activity, and plains are formed in areas that are little susceptible to mountain-forming processes.
Plains- large areas with flat or hilly surfaces. They vary in height. An example of a lowland is the Amazon lowland - the largest on Earth. It happens that lowlands are located below sea level - these are depressions. The Caspian lowland is located 28 m below sea level. At an altitude of 200-500 m above sea level there are hills, for example Central Russian, and above 500 m there are plateaus. An example of such a plain is the Central Siberian Plateau.
Mountains- areas of the earth's surface elevated above sea level to a height of more than 500 m. Mountains are considered low if their height is from 500 to 1000 m; medium - from 1000 to 2000 m and high - over 2000 m. The highest mountain on Earth - Chomolungma (Everest) has a height of 8848 m. You can determine the height of the mountains from a physical map, using an altitude scale.
Mountains differ not only in height, but also in shape. A linearly elongated group of mountains is called a mountain range. The Caucasus Mountains have this shape.
There are also mountain belts (Andean belt), mountain systems (the mountain system of Southern Siberia) and mountainous countries. The Pamirs are an example of a mountainous country.
Mountains and plains are located both on continents and in oceans. An example of mountains in the ocean are mid-ocean ridges.
Relief of the Earth- the result of the struggle between internal and external forces. The internal forces of the Earth form large relief forms: continents and oceans, mountains and plains. They not only form them, but also change and destroy them. External forces work constantly and slowly. They also destroy mountain ranges, fill up deep depressions, form hills, valleys, gullies, ravines, form river beds, that is, they form smaller landforms.
The destruction and change of rocks under the influence of fluctuations in air temperature, moisture and living organisms is called weathering.
Here are some examples of weathering. In the mountains these are landslides, landslides, mudflows, rockfalls, deep gorges cut by mountain rivers, moraine deposits of glaciers. For plains, typical examples of weathering are ravines and river valleys.

Questions for students:

Who remembers from the 6th grade course what relief is? (Relief is a set of irregularities on the earth's surface). Students write down 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 upside-down cards with terms:

Fig.1. Block diagram “Earth Relief”

Students fill out the diagram in their notebook.

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 elevation differences on it from the Himalayas to the Mariana Trench reach two tens of kilometers. The topography of our planet continues to form even now: lithospheric plates collide, crushing into folds of mountains, volcanoes erupt, rivers and rains erode rocks. If we ended up 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 would have changed beyond recognition during this time. All processes that shape the Earth's topography can be divided into two large groups: internal and external. Otherwise, internal ones 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.

Land relief

Plains

Lowlands - up to 200 m

Hills - 200-500 m

Plateau - more than 500 m

Mountains

Low - 500-1000 m

Medium - 1000 - 2000 m

High - 2000 - 5000 m

The highest - more than 5000 m

Ocean relief

Basins - depressions in the ocean floor

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 all the way to the mantle. 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 immersion of one lithospheric plate in this place under another.

2. Formation of plains and mountains

The teacher builds an explanation according to this scheme. As the teacher tells the story, students transfer the diagram to their notebooks.

Rice. 2. Formation of plains

Planation. The oceanic crust (soft and thin) easily folds into folds, and mountains can form in its place. Then the rocks composing 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.

As soon as they are born, mountains begin to slowly but steadily collapse under the influence of external forces - wind, water flows, glaciers, and simply temperature changes. A large number of clastic rocks accumulate in foothill and intermountain troughs, with smaller ones at the bottom and increasingly coarser ones at the top.

Old (blocky, revived) mountains. The oceanic crust was crushed into folds, they were destroyed to the state of plains, then the Alpine era of folding revived the mountainous relief in place of the destroyed mountain structures. These low mountains have a small height and a blocky appearance. Next, students, working with tectonic and physical maps, give examples of ancient mountains (Urals, Appalachians, Scandinavian, Draconian, Great Dividing Range, etc.)

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

Rice. 4. Ural Mountains

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

Rice. 5. Middle (block-folded and folded-block renewed) mountains.

Rice. 6. Northern Santiago. Cordillera

Young mountains are still being formed. Being young mountains, they show no signs of destruction. Basically, these mountains are high and have the appearance of folds. Often their peaks are sharp and covered with snow caps. Vivid examples of young mountains are the Alps, Himalayas, Andes, Caucasus, etc.

Fig.7. Young Mountains

Rice. 8. Caucasus. Dombay.

3. Internal and external forces of the Earth

Questions for students:

Tell me why the oceanic crust turns into mountains? (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 appearance of the topography of our planet? (internal and external).

For a long time, granite has been the personification of durability and strength. A strong-willed, unbending person and an unbreakable, faithful friendship can be equally compared to granite. However, even granite will crumble into fine crushed stone, crumbs and sand if it experiences temperature changes, wind influences, and the activity of living organisms and humans for a long time.

Temperature changes. With the first rays of the Sun, snow and ice begin to melt high in the mountains. Water penetrates into all cracks and cavities of rocks. At night, the temperature drops several degrees below zero and the water turns to ice. At the same time, it increases in volume by 9% and pushes the cracks apart, widening and deepening them. This continues day after day, year after year, until some crack separates a piece of rock from the main mass and it rolls down the slope. Rocks also undergo heating and cooling. The minerals they contain have different thermal conductivities. Expanding and contracting, they break strong connections between themselves. When these bonds are completely destroyed, the rock turns into sand.

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

The active influence of plant and animal organisms on rocks causes biogenic weathering. Plant roots undergo mechanical destruction, and the acids released during their life activity cause 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 the calcareous skeletons of marine animals.

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

Rivers and the World Ocean also leave their mark on the Earth's topography: a river forms a channel and a river valley, ocean waters form a coastline. Surface waters leave scars of ravines on the surface of hills and plains. As the ice moves, it furrows the surrounding areas.

Fig. 12. Bryce Canyon in the USA, formed as a result of the activity of flowing waters

Rice. 13. The 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 wind is the absolute master of open spaces. Encountering obstacles on its way, it forms majestic hills - dunes and dunes. In the Sahara Desert, the height of some of them reaches 200 - 300 meters. In mountain ranges located in the desert, there is almost never loose material filling the depressions and cracks. This is why aeolian landforms appear, resembling towers, pillars and fancy castles.

Rice. 15. Remains in the desert resemble fairy-tale castles

Rice. 16. Sand dunes.

Relief is a set of irregularities on the Earth's surface, characterized by different ages, development history, nature of occurrence, outline, etc. Relief can be considered as part of the landscape. It refers to the geographic features that control climate, weather, and the essence of life on Earth. In simple words: any shape on the surface of the Earth is known as landform.

Topographic relief map of the Earth

Origin of the relief

The various landforms we have today are due to natural processes: erosion, wind, rain, weather conditions, ice, chemical influences, etc. Natural processes and natural disasters such as earthquakes and volcanic eruptions have created the various landforms earth's surface that we see today. Water and wind erosion can wear down land and form landforms such as valleys and canyons. Both processes occur over a long period of time, sometimes taking millions of years.

It took about 6 million years for the Colorado River to cut through the US state of Arizona. The length of the Grand Canyon is 446 kilometers.

The highest landform on Earth is Mount Everest in Nepal. Its peak is at an altitude of 8,848 meters above sea level. It is part of the Himalaya mountain system, which is located in several Asian countries.

The deepest relief on Earth (almost 11,000 m) is the Mariana Trench (Mariana Trench), which is located in the South Pacific Ocean.

Basic landforms of the earth's crust

Mountains, hills, plateaus and plains are the four main types of landforms. Minor landforms include outcrops, canyons, valleys, basins, basins, ridges, saddles, hollows, etc.

Mountains

A mountain is a large landform that extends above the surrounding land in a limited area, usually in the form of a peak or mountain system. A mountain is usually steeper and higher than a hill. Mountains are formed through tectonic forces or volcanism. These forces can locally lift the Earth's surface. Mountains are slowly being eroded by rivers, weather and glaciers. A few mountains are individual peaks, but most are found on huge mountain ranges.

At the tops of high mountains the climate is colder than at sea level. Weather conditions greatly influence: for different altitudes there is a difference in flora and fauna. Due to their less favorable terrain and climate, mountains tend to be used less for agriculture and more for recreational activities such as mountaineering.

The highest known mountain in the solar system is Olympus Mons on Mars - 21171 m.

Hills

Hills are a landform that protrudes above the surrounding area. Their distinctive feature, as a rule, is a rounded or oval top.

There is no clear worldwide distinction between a hill and a mountain and it is largely subjective, but a hill is widely considered to be shorter and less steep than a mountain. The Great Soviet Encyclopedia defines a hill as a hill with a relative peak height of up to 200 m.

Plateau

A plateau is a flat, elevated topography that rises sharply above the surrounding terrain on at least one side. Plateaus are located on every continent and occupy a third of the landmass of our planet and are one of the main landforms of the Earth.

There are two types of plateau: dissected and volcanic.

• A dissected plateau is formed as a result of upward movement in the earth's crust. The elevation is caused by the slow collision of tectonic plates.

The Colorado Plateau, in the western United States, has been growing about 0.3 centimeters per year for more than 10 million years.

• The volcanic plateau is formed by numerous small volcanic eruptions that slowly build up over time, forming a plateau of lava flows.

The North Island Volcanic Plateau covers a large area of ​​the central North Island of New Zealand. This volcanic plateau still has three active volcanoes: Mount Tongariro, Mount Ngauruhoe and Mount Ruapehu.

A valley is formed when river water cuts through a plateau. The Columbia Plateau, located between the Cascade and Rocky Mountains in the northwestern United States, is cut by the Columbia River.

Erosion also forms a plateau. Sometimes it becomes so eroded that it breaks into smaller, raised areas.

The largest plateau in the world is the Tibetan Plateau, located in Central Asia. It extends through Tibet, China and India, covering an area of ​​2.5 million km².

Plains

In geography, a plain is a flat, broad surface of the Earth that usually does not vary much in height (variation in height is no more than 200 meters, and the slope is less than 5°). Plains occur as lowlands along mountain valleys, coastal plains, or small uplands.

The plain is one of the main landforms on our planet. They are present on all continents and cover more than one-third of the world's landmass. Plains are typically grassland (temperate or subtropical), steppe (semi-arid), savanna (tropical), or tundra (polar) biomes. In some cases, deserts and tropical forests can also be plains.

However, not all plains are grasslands. Some of them, such as the Mexican Tabasco Plain, are covered with forests. Forested plains have different types of trees, shrubs and other vegetation.

Can also be classified as plains. Part of the Sahara, the great desert in North Africa, has a flat topography.

In the Arctic, where the ground freezes, the plains are called. Despite the cold, many animals and plants survive here, including shrubs and moss.

Relief elements

Land shapes are classified by characteristic physical features such as height, slope, orientation, rock exposure, and soil type. Terrain includes such features as berms, ridges, cliffs, valleys, rivers, islands, volcanoes, and many other structural and dimensional (i.e., ponds and lakes, hills and mountains) features, including various types of inland and oceanic features. reservoirs, as well as subsurface objects.

Elements of individual relief forms include: lines, points, surface angles, etc.

Relief levels

The relief can be classified as follows:

First level relief

The entire lithosphere, consisting of continental and oceanic crust, is located under the first-level relief.

Continental crust is less dense than oceanic crust and consists primarily of granitic rock, which includes silica and aluminum. While the oceanic crust consists of basaltic rocks, silica and magnesium.

The relief of the first level mainly reflects the initial cooling and hardening of the earth's crust at the time of its formation.

Second level relief

This type of relief mainly consists of all the endogenous forces that occur within the earth's crust, in its depths. Endogenous forces are responsible for the development of variations in the earth's surface.

Endogenous processes are classified as follows:

• Diastrophism is the deformation of the earth's crust under the influence of the internal energy of our planet;
• Volcanism/Earthquakes.

Mountains are the best example of the product of endogenous processes on the continental crust, and in the oceanic crust there are submarine ridges and trenches.

Third level relief

This type of relief is mainly composed of exogenous forces. Exogenous forces are those forces that arise on the surface of the Earth.

All exogenous forces are responsible for leveling the surface of the planet. The leveling process involves erosion, transport and deposition, resulting in the formation of valleys (due to erosion) and deltas (due to deposition). The following are natural phenomena that perform the entire leveling process:

• Running water (rivers);
• Wind;
• The groundwater;
• Glaciers;
• Sea waves.

Important note: All of the above phenomena do not work beyond the boundaries of the coastline. This means that the third level relief is limited only by the continental crust.

However, the continental margin (the area of ​​the ocean floor located between the deep sea region and the coastline) may exhibit features of third-level landforms due to changes in mean sea level, climatic conditions, or region-specific processes.

Height of the area above sea level

The altitude of the area above sea level shows at what distance relative to the mean sea level (taken as zero) the measured territory (if it is a flat area) or a certain object is located.

Mean sea level is used as a base level for measuring depth and height on Earth. Temperature, gravity, wind, currents, climate and other factors affect sea level and change it over time. For this and other reasons, recorded altitude measurements may differ from the actual altitude of a given location above sea level at that time.

In the CIS countries, the Baltic height system is used. The device for measuring the height of the Baltic Sea is called the Kronstadt footstock and is located in the abutment of the Blue Bridge, in the Kronstadt district of St. Petersburg.

Relief age

When it comes to measuring the age of landforms, the following terms are used in geomorphology:

• The absolute age of the relief is expressed in the period of time, usually in years, during which the characteristic unevenness was formed.

• The relative age of a relief is a reflection of its development to a certain stage. In this case, the age of the landform can be determined by comparing it with other landforms.

Relief value

Understanding terrain features is critical for many reasons:

• Relief largely determines the suitability of an area for human settlement: flat, alluvial plains tend to have better soils suitable for agricultural activities than steep, rocky hills.

• In relation to environmental quality, agriculture and hydrology, understanding the topography of a land allows us to understand the boundaries of watersheds, drainage systems, water movement and the impact on water quality. Comprehensive terrain data is used to predict river water quality.

• Understanding topography also supports soil conservation, especially in agriculture. Contour plowing is a common practice for sustainable farming on slopes; such plowing is characterized by cultivating the soil along elevation lines, rather than up and down the slope.

• Terrain is critically important during warfare because it determines a military force's ability to capture and hold areas and move troops and supplies. Understanding the terrain is fundamental to both defensive and offensive strategy.

• Relief plays an important role in determining weather conditions. Two areas that are geographically close to each other can differ radically in precipitation levels due to differences in elevation or the "rain shadow" effect.

• Accurate knowledge of the terrain is vital in aviation, especially for low-flying routes and maneuvers, as well as airport altitudes. Terrain also affects the range and performance of radars and ground-based radio navigation systems. In addition, hilly or mountainous terrain can greatly affect the construction of a new airfield and the orientation of its runways.

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 ones.

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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The “quiet” life of the Earth’s rock shell ends as soon as it comes into contact with water or gases. Then amazing transformations occur on the earth's surface and phenomena are observed that simply cannot occur in the deep interior.

The relief of the Earth is a combination of various surface irregularities, both large and small, resulting from the activity of external and internal forces. An important role in the formation of relief is played by gravity, density and composition of rocks, activity and flowing waters. The formidable forces of nature, setting in motion the strongest rock masses, both destroy them to the ground and create new mountains, gorges and valleys. Even then, huge plains appear, which over time become covered with silt and large debris. This happens quite slowly, and the entire human life is not enough to notice changes in the surface. It’s as if it’s breathing - it rises and falls, waves run through it, it bursts from the stress that has arisen.

On the surface of the planet there is a circulation of water (from to land and further to), a change in vegetation cover and the migration of animals, the movement of large debris and the smallest debris. Scientists consider all this to be a process of exchange of matter and energy, which leads to the formation of loose sediments, and at the same time to the formation, i.e., to the process of morpholithogenesis. Even if a few grains of sand are moved or water moves a short distance, a small hole or bump will appear on the surface. However, morpholithogenetic analysis reveals only part of the connections between relief, atmosphere and natural waters. The other part of the connections is shown by morphostructural analysis.

Morphostructures are called geological structures expressed in modern relief. The largest morphostructures on Earth are. They belong to planetary morphostructures, within which there are mountain belts, plateaus and plains, underwater ridges and basins, differing in the structure of the earth's crust, type and speed, and the degree of participation of other factors in their formation. Thus, planetary morphostructures consist of smaller regional morphostructures.

The relief of large regions has been formed over many millions of years. At the sites of ancient platforms, a crystalline foundation composed of gneisses, granites, shales and sandstones usually emerges on the surface. Such a foundation serves as a base, a plinth, for the relief, and the structures made up of these rocks are called plinth plains. In Russia they can be found in, on, in the north of Siberia.

Analysis is used in the study of large landforms composed of different rocks; tectonic movements that caused the appearance of large relief forms; discontinuous faults - faults that limit morphostructures.

If we talk about the age of the relief of large mountain belts, then it is obvious that their age is at least 200 million years; if we are talking, for example, about the age of the Caucasus Mountains, then it will be 80 - 90 million years. In both cases, to determine the age of the relief, you need to know the beginning of the appearance of its largest and most characteristic forms. In mountainous areas, this is the formation of not only ridges, but also intermountain depressions. Often, to determine the time of the beginning of the division of the relief into hills and elevations, mountains and depressions, the age of one of the ancient alignment surfaces is taken as the initial reference point. This is the name given to the undulating plain that existed in many places in the past, weakly dissected by erosion.

The beginning of the division of the plain is the starting point for determining the age of the relief.

Relief age- the time that has passed since the formation of its modern appearance. It is measured in a single time - in years, hundreds, thousands, millions of years, although time ranges are often used, calling the relief Mesozoic, Neogene-Quaternary, Late Pleistocene, etc.

Formation of the Earth's relief

Features of the Earth's relief