What reliefs are there in South America? Landscapes of South America

Geography 7th grade

Lesson topic: Relief and minerals of the continent of South America

Date…………….

Lesson Objectives: Continue to develop students’ ideas about the nature of South America; remember what is already known and discuss new terms and concepts with students; to form their ideas about the tectonic structure, relief and mineral resources of South America - their composition, origin, structure; introduce students to the relief objects of South America; continue to develop the ability to establish cause and effect relationships by comparing various geographical maps.

Equipment: map of the structure of the earth's crust, physical map of South America, wall contour map.

Lesson progress

Testing the knowledge gained in the last lesson. Without using cards, determine and justify the correctness of the statement. In the answer column, put a sign (+) - if the statement is true, (-) - if it is false. Answer the question.

Justification for incorrect answers_______________________________________________

Reflection

- Why is it necessary to know the geographical location of the continent?

I - setting the cognitive task of the lesson

1. Terms and concepts. Select those that you already know and write them in the first column.

Platform, young mountains, shield, foundation, lowland, plateau, plateau, Amazonian, Brazilian, Orinoco, La Plata, Andes, graben, Aconcagua, Cotopaxi.

I invite students to fill out the table

2. Reflection. We check what is written in the “I want to know” column. We look for these concepts on the map of South America. Setting the cognitive task of the lesson. Study the relief features of South America.

3. Create a cluster on the topic “Relief of South America.” Place arrows that show the relationship between the relief and its diversity.

4. Work in groups to characterize one of the landforms according to a plan that students draw up independently. Each group makes messages. Characterized by such landforms as: Andes, Amazonian lowland,

Orinoco Lowland, Brazilian Plateau, etc.

5. Testing the knowledge gained from studying the topic of relief of South America.

1. Why do you need to study the topography of the territory?

2. What cards should I use?

3. Why are the mountains located in the western part of the mainland?

4. Find the highest mountain?

5. What volcanoes are there in the Andes?

6. What is the dependence of relief on the structure of the earth’s crust?

6. Work in groups to identify minerals.

One group evaluates mineral resources located in the Andes mountains, another on the Brazilian plateau, and a third on the lowlands.

The dependence of types of minerals on the structure of the earth's crust is revealed.

Identification of cause and effect relationships(filling out a systematizing table)

Using atlas maps, fill out a systematic table and, based on a comparison of relief, structure and minerals in the Andes Mountains, the Brazilian Plateau and the Amazonian Lowland, identify cause-and-effect relationships

Knowledge test. Digital dictation “Surface shapes of South America.”

1. Orinoco Lowland

2. Amazonian lowland

3. Brazilian flathorn

4. Guiana Highlands

5. Andes Mountains

What are they called:

A) the largest plain on earth?

B) an area of ​​South America where catastrophic earthquakes occur?

C) a plain rich in oil?

D) highlands rich in gold and diamonds?

D) a highland that gradually decreases to the northwest?

E) a highland characterized by the highest altitudes in the central part?

G) mountains whose name means “copper” in the local language?

Students check the correct spelling themselves.

Homework: create a geologist’s route across the continent of South America. Assess mining conditions.

South America, the southern continent of the Western Hemisphere, between the Pacific Ocean in the west and the Atlantic Ocean approx. in the east, the Caribbean Sea in the north and the Magellanic Sea in the south, from 12° 28" N to 53° 55" S. w. Connected by the Isthmus of Panama to the North. America. The area with islands is 18.28 million km 2. The greatest length is 7150 km, width 5100 km. The relief is distinguished by the powerful mountain belt of the Andes (Aconcagua, 6960 m) in the north and west and the platform, flat-platform east. The uplifts of the platform correspond to the Guiana plateau (Neblina town, 3014 m) in the northeast and the Brazilian plateau (Bandeira town, 2890 m) in the east, separated by a trough occupied by the Amazonian lowland (Amazonia). In the marginal and foothill troughs between the plateaus and the Andes there are plains and lowlands: the Orinoco and Interior Plains (Pantanal, Gran Chaco, Mesopotamia and Pampa); to the south of it, in the southeast, the Patagonian plateau rises to 2200 m. On the plateaus there are large deposits of iron and manganese ores, bauxite, non-ferrous and rare metals; oil and gas in the foothills and intermountain troughs of the Andes; in the mountains there are deposits of copper ores, polymetals, tin, etc.

Relief

The relief of South America clearly distinguishes the flat-platform platform extra-Andean East and the mountainous Andean West, corresponding to the mobile orogenic belt. The uplifts of the South American platform are represented by the Guiana, Brazilian and Patagonian plateaus, the troughs - by the lowlands and plains of the Llanos-Orinoco, Amazon, Beni-Mamore, Gran Chaco, Mesopotamia (Parana and Uruguay rivers) and Pampa; from the east the plateaus are framed by narrow intermittent strips of coastal plains.

Extra-Andean East. Located on the South American platform. Its uplifts are expressed in relief by plateaus (Guiana and Brazil), and troughs - by lowlands (Amazonian, Orinoco, La Plata) and highlands (Gran Chaco). At the base of the platform lie the cores of the most ancient (Early Precambrian) igneous and metamorphic rocks that come to the surface in the Guiana, South Brazilian, and West Brazilian shields.

Tectonic movements divided the plateaus, in particular the Brazilian plateau, into separate blocky massifs. Basalt outpourings formed the Paraná lava plateau, the largest on Earth, in the southern part of the Brazilian Plateau.

The EpiPaleozoic Pampa-Patagonian plate, attached to the southeastern part of the Andes and the south of the South American platform, formed much more mobile. It often alternates between uplifts and subsidences with sedimentary strata folded into short gentle folds.

The relief of the low-lying plains is extremely monotonous. They were formed in the syneclises of the South American platform plate, which were gradually filled with sedimentary deposits. The relief of the Amazonian lowland, covering an area of ​​5 million square meters, is extremely monotonous. km. Even at the foot of the Andes, the altitude in the Amazon Valley is only 150 m above sea level. seas. In the less extensive Orinoco Lowland and on the Interior Plains, the areas closest to the Andes are usually elevated due to the removal of abundant sediment from the mountains and lowered to the axes of troughs, emphasized by the flow of the main rivers - Orinoco, Mamore, Paraguay, Parana; along the latter stretches the swampy La Plata lowland.

The Andes ridge system extends over 9,000 km to the north and west of the continent. In the north and northeast, in Venezuela, there are two chains of the Caribbean Andes, deeply dissected by faults and river erosion. The main, meridional system of the Andes, or Andean Cordillera (Cordillera de los Andes), reaching 6960 m (Aconcagua), rises in the west of South Africa and is divided into the Northern, Central and Southern Andes. The northern Andes (up to 5° S) are distinguished by the alternation of high folded-block ridges and deep depressions. In Ecuador, they consist of the Eastern and Western Cordilleras, the depression between which is filled with the products of the volcanoes Chimborazo, Cotopaxi, etc. In Colombia, there are three main Cordilleras (Eastern, Central and Western), separated by the depressions of the Magdalena and Cauca rivers. Volcanoes (Hila, Ruiz, Purase, etc.) are concentrated mainly in the Central and Southern Western Cordillera; For the central part of the Eastern Cordillera, ancient lake plateaus are typical, with an altitude of 2-3 thousand m. In the north and west lie the largest lowlands in the Andean west - the Caribbean and Pacific.

The Central Andes (up to 27-28° S) are much wider and more monolithic than the Northern Andes. They are characterized by internal plateaus raised to 3.8-4.8 thousand m, bordered by marginal ridges; the highest mountains bear significant glaciation. The southern part is the Central Andian Highlands - the widest (up to 750 km) section of the Andes; its main element is the Puna plateau with the ancient lake plateau of the Altiplano in the southwest and a number of blocky ridges in the east and south. In the east, Puna is framed by the Cordillera Real, with the western volcanic Western Cordillera (the 2nd volcanic region of the Andes with the volcanoes of Misti, Llullaillaco, Sajama, etc.), a longitudinal tectonic basin (with the Atacama Desert) and the Coastal Cordillera.

In the Southern Andes in the north (up to 41°30" S) the relief is expressed by: the double Main Cordillera (the city of Aconcagua in the eastern, or Front), to which the Precordillera massifs are attached to the east; the Longitudinal Valley of Chile and the Coastal Cordillera. Between 33-52° S there is another volcanic region of the Andes with a large number of active volcanoes to the west of the Main Cordillera and extinct ones to the east of it. In the southernmost section of the Andes - the Patagonian Andes - the Coastal Cordillera turns into an archipelago of islands. The longitudinal valley is in the system of straits, and the flooded troughs of the sharply declining Patagonian Cordillera are in the fjords. Modern glaciation in South Africa covers an area of ​​25 thousand km 2, of which over 21 thousand km 2 are in the Southern Andes. There are also glaciers in the Western Cordillera, between 9 and 11° latitude and on the islands of Tierra del Fuego.

Guiana Plateau rises towards the center (Mt. Neblina, 3014 m), Brazilian - from the north-west. to the south-east (city of Bandeira, 2890 m), Patagonian - from east to west (up to 2200 m). The relief of the Guiana and Brazilian plateaus is dominated by basement gently undulating plains (up to 1500-1700 m high), within which there are remnant cone-shaped peaks and ridges (for example, Serra do Espinhaço) or table, mostly sandstone, hills - the so-called chapadas (Auyan-Tepui and Roraima, etc.). The eastern edge of the Brazilian Plateau is divided into separate massifs (Serra da Mantiqueira, etc.), which have characteristic “sugar loaf” shapes (for example, Pan de Azucar in Rio de Janeiro). The troughs and depressions of the Brazilian Plateau in the relief are expressed as monoclinal-layered plains with raised edges-cuestas, accumulative plains (the depression of the São Francisco River, etc.) or a lava plateau (in the middle reaches of the Paraná). The relief of Patagonia is dominated by layered, including volcanic, stepped plateaus, covered by ancient moraine and fluvio-glacial deposits; the plateaus are cut by deep canyons of rivers emerging in the Andes; arid forms of denudation are characteristic.

On the territory of the mainland there are several large lowland plains: Amazonian, Orinoco, Mamore, Pantanala, Mesopotamia, Pampas, as well as several high, highly dissected plains: the Guiana, Brazilian plateaus, Patogonian plateau.

Amazonian lowland- the largest equatorial lowland in the world (area about 5 million km 2), crossing from west to east almost the entire continent of South America, from the foothills of the Andes to the Atlantic Ocean, and lying between the uplifts of the Guiana Plateau in the north and the Brazilian Plateau in the south.

The powerful trunk of the deepest river in the world, the Amazon, is the axis of the lowland, which received its name from it. The even green tone of the physical map, as if covering the blue branch rivers with foliage, indicates the amazing flatness of the territory. The humid equatorial climate, characteristic of the Amazon, is considered the most uniform and monotonous on Earth. It is difficult to find a more integral spot on the world soil map than the podzolized lateritic soils of the Amazonian lowland, cut only by green veins of alluvial soils along the rivers. The continuous thicket is represented by humid equatorial forests - hylaea, which are most widespread in the Amazon.

The flat territory along the left bank of the Orinoco River, between the Andes in the west and north, the Guiana Plateau in the southeast and the Guaviare River in the south, is called Llanos Orinoco. It stretches approximately 1 thousand km in length, 300 km in width and mostly belongs to Venezuela, only entering Colombia in the southwest.

Vast open low-lying spaces covered with tall, dense grass, and here and there scattered individual trees or groups of palm trees - this is the appearance of a typical llanos savanna.

The position at very low latitudes provides the Orinoco Lowland with high temperatures (+250; +280 C) throughout the year. In contrast to the course of temperatures, the precipitation regime is extremely uneven. Dry and wet periods are clearly defined, the duration and continuity of which varies with geographic latitude. During drought, all organic life freezes, developing rapidly with the onset of rains. This seasonality in the development of the landscape is the most characteristic and general feature of the Orinoco Plains region.

Mamore Plain. Most of the foredeep between the Andes and the Brazilian Highlands is a tropical lowland region with high temperatures and a distinct seasonality in the distribution of precipitation, with a variety of vegetation types adapted to withstand prolonged droughts or floods, with capricious rivers that dry up and overflow their banks and flood vast spaces. This meridianally elongated territory makes up the eastern regions of Bolivia in the north, belongs to Paraguay in the southeast and extends into Argentina in the southwest.

The interfluve of Parana and Uruguay (“Argentine Mesopotamia”) represents another, eastern region of the Interior Plains. Vast overgrown swamps and swamps, poorly drained by barely flowing rivers, many kilometers of floods of large waterways, groves of palm trees on elevated sandy shores and hills and reed thickets in the lowlands. But in open steppe areas, cooler ones with a mild subtropical climate, evergreen trees (except for palm trees) are almost completely absent.

The climate of Mesopotamia is subtropical with abundant and fairly uniform precipitation and high temperatures.

Pampa– treeless plains overgrown with grass. It is located in the area of ​​the greatest trough of the La Plata syneclise, along the axis of which the Paraná flows. On the right bank of the Paraná, a new landscape region begins - the subtropical Pampa steppe. Atmospheric precipitation falls mainly in the summer, but the forests of quebracho and mimosa are thinning, trees become an unusual phenomenon, the grass cover is more dense, and gray-brown soils are replaced by black soils.

Brazilian plateau geostructurally it consists of a number of anticlines (shields) and syneclises (slabs). Along with the processes characteristic of the Guiana Plateau - long-term destruction, peneplanation, clearing of the sedimentary cover and exposure of the crystalline base, recent repeated uplifts, etc., faults (in the east) and the filling of internal depressions with marine , volcanic and clastic strata. Washout predominates in the northern and eastern (more elevated and humid) regions, accumulation - in the central trough.

Crystalline surfaces, mainly in the east and north-west, are characterized by ancient denudation surfaces weakly dissected by rivers - peneplains - at an altitude of 400-800 m above sea level. seas with remnant island peaks and “serre” fault ledges. Along the right bank of the river. In São Francisco, the roots of “brasilids” were prepared by denudation, forming ridges up to 1500-2000 m high (Serra do Espinhaço and others).

Patagonia Plateau formed on the young Patagonian platform with a Hercynian basement, connected in the west by a tectonic “seam” with the Andes. Like the northern plateaus, the Patagonian platform was subject to uplifts and faults with differentiated movements of individual blocks, in particular those constituting the marginal uplifts of the “Gondwanians” and the intraplatform block massifs of the “Patagonides”. Over large areas of Patagonia, a cover of continental and marine horizontal deposits of the Mesozoic and Cenozoic has been preserved, contributing to the overall evenness of the relief. Powerful Quaternary glaciation in the Patagonian Andes, with glaciers covering the southern part of Patagonia, left traces in the form of a pebble cover of eroded fluvioglacial deposits. The relief is characterized by stepped plateaus, on average up to 1000-1500 m in height, descending in ledges east to the coast of the Atlantic Ocean, where a series of abrasion terraces are expressed. The uplifts caused deep incision of rivers formed along cracks, transitively, without receiving tributaries, in deep and wide canyons crossing Patagonia.

Without exception, all the continents on our planet are unique in their geological structure, including the relief of this area is divided into two parts: mountainous terrain and flat terrain, with large lowlands. Thanks to this, this continent has become the greenest on the planet and the wettest, but in parallel with this, there are the driest desert valleys and very high snowy peaks. Well, let's take a closer look at what the relief of South America is like and how it is related to the climate of this area.

Geology and its fundamentals

It is known that the basis of all earthly landscapes is composed of In some places they diverge, due to which they form depressions. In others they overlap each other to form mountains and hills. South America is not without this phenomenon. The relief of the continent is usually divided into West and East. The first is presented in the form of mountains and arid valleys, the second - continuous plains with areas of lowlands.

The reasons for this difference lie in the history of the formation of the Earth. The eastern part of the continent is located on the oldest flat platform, which is unshakable. The western part is located at the junction of the continental and oceanic plates, which still seem to be pushing against each other. Thanks to this process, the Andes, the longest mountain range in the world, were formed and continue to form. We can conclude that the relief of South America in the western part is still being formed. The height of the mountains is constantly rising, and volcanic processes and earthquakes do not subside.

The East and its plains

This geological region occupies most of the continent of South America. The relief here, as we have already said, was formed billions of years ago, and now it is firmly supported by a single lithospheric plate, which is seismically stable. In general, the east of the continent consists of six parts. The largest part of the territory is occupied by the Brazilian and They are located on the shields of the South American lithospheric plate. On the slabs there are three Amazonian and Orinocian. The last component of the relief is Patagonia. This is a stepped plateau, the height of which rises to 2000 m. It is located in the southeast of the continent, in the possession of Argentina.

Eastern Plains Climate

The eastern part of South America is such that there are no mountains or high hills there. Therefore, winds and cyclones from the Atlantic freely penetrate the land, irrigating it with rain, rewarding it with fog and thick clouds.

Above this area there is a zone of low pressure, which is “fed” by the Atlantic trade winds. As a result, the maximum amount of precipitation in the world falls here. Thanks to them, the beds of the Amazon, the largest river in the world, are so deep. And they are surrounded by impenetrable tropical jungles inhabited by unique evergreens.

Structure of the West

This part of the continent is very narrow, and at the same time it seems to stretch from north to south. It is still being formed, which is why earthquakes occur here almost every year, and volcanoes erupt every 10-15 years. Here, the relief of the mainland of South America is usually divided into two parts: the Andes mountains and the flat Atacama Desert. The length of the ridge is 9,000 kilometers - it is the longest in the world. The highest point is its height - 6962 meters. This ridge is not only a watershed, but also a barrier to Pacific cyclones. Cold winds from the Antarctic currents that pass here only reach the Atacama Hills, without falling deep into the continent.

Climate data

The Andes occupy the entire western coast of the mainland of South America. The terrain is divided into three parts: North, Center and South. The first of them is the wettest - there is an atmospheric dynamic minimum. The amount of precipitation per year sometimes reaches 7000 mm, and on average - 4000 mm. The middle part of the Andes is the widest (up to 500 km), and the pressure here gradually increases. The amount of precipitation per year is up to 1500 mm, sometimes there are droughts up to 500 mm. Temperature changes are sharper both at the foothills and in the high zone. This is due to the fact that the Atacama, the driest desert in the world, is located nearby. In some areas there has been no rain or fog for as many as 400 years. The southern Andes are the driest. Temperature differences here are maximum, sometimes reaching 40 degrees. Precipitation amount - 250 mm.

Landscapes of South America

The geological structure of any continent as a whole determines its flora and fauna and creates the landscape of the area. The landscapes that we can find in South America are incredibly diverse, and at the same time, every corner of this continent remains unique, because there are no such beauties anywhere else.

So, the eastern shores, which are washed by the Atlantic, are gently sloping beaches. Gradually they turn into small hills (a typical example is Rio de Janeiro). In other parts of the continent the terrain is completely flat (Buenos Aires). In the center of the continent, the level decreases, which contributes to the formation of wooded areas and numerous rivers. These are the famous South American jungles and the Amazon. The West appears in the form of tall mountains covered with perennial snow and glaciers. Closer to the shores of the Pacific Ocean, they turn into hills, where the earth is literally cracked from many years of drought. Here you can often find canyons of reddish rocks, which only in the spring are covered with grasses and flowers, and in the summer they turn into a windy desert.

Results

We briefly looked at what the relief of South America is like. 7th grade is a period when children study in detail the structure of the various continents of our planet. To help them learn the material, it is best to provide illustrations of each individual part of the continent so that the brain can connect the general information with the visual images.

Features of the geological structure of South America

Millions of years ago there was an ancient supercontinent Gondwana . It broke up into three large blocks of lithosphere, which formed the basis of four modern continents: Africa, Australia, Antarctica and South America . The latter will be discussed in this article.

In the geological structure of South America, a clear difference between the eastern and central parts and the western part of the continent is clearly visible. The east and center of the continent are located on the old Precambrian South American platform . In the north and east of the platform there are extensive areas of exposure of the ancient crystalline foundation of the platform to the surface - Guiana and Brazilian shields . The western part of the continent is represented folded area , formed as a result of the collision of a continental platform and an oceanic lithospheric plate.

The oceanic plate bends and moves under the continental plate, forming a deep Peruvian trough (trench) along the entire west coast.

The edge of the continental plate is folded. Mountains rose along the entire western edge of the continent. This is a young area - Cenozoic folding . This is evidenced by volcanic eruptions and frequent earthquakes. There is an active process of mountain building. The west coast of South America is part of "Pacific Ring of Fire" – areas of active seismic activity.

The platform part of the continent has experienced repeated subsidence and uplift in the past. This is evidenced by sedimentary rock deposits, including marine sediments.

Currently, erosion processes, enhanced by human economic activity, prevail on the platform part of the continent.

Relief features of South America

The folded region in western South America forms one of the largest mountain systems on the planet - Andes mountains . In Indian language this means "copper mountains" .

The Andes Mountains stretch along the Pacific coast in three parallel mountain ranges. Many peaks rise above $6000$ m above sea level.

Highest point in South America Aconcagua ($6960 m).

At the same time, it is the highest point of the entire Western Hemisphere.

There are also many active volcanoes here. The most famous of them are Cotopaxi, Ruiz, San Pedro . In the middle part of the mountain system there are internal plateaus, the heights of which reach $3500-4000 $ m. The platform areas of South America are represented by plains - lowlands and plateaus.

Definition 1

Lowland – this is a section of plain with absolute heights up to $200$ m.

Definition 2

Plateau – this is a section of plain with absolute heights of more than $500$ m.

The lowlands of South America are Orinoco, Amazonian and La Plata . The elevation difference here is insignificant. These are almost flat plains.

Note 1

Amazonian lowland - the largest lowland in area on the globe.

Thanks to marine sediments, the northern parts of the plains are rich in oil. Formed on crystalline shields Brazilian and Guiana plateaus . As a result of ancient tectonic activity, the lowering and raising of the platform was accompanied by faults in the earth's crust and lava outcrops. In some places, the relief of the plateaus has the appearance of table mountains. They are replaced by landscapes of rolling plains, low massifs, cut by gorges.

Minerals

The distribution of minerals is also related to the geological structure.

• Deposits are located on ancient shields iron, manganese, uranium ores, bauxite, diamonds.
• The Andes, true to their name, are famous copper ores, deposits gold.
• Large deposits discovered in the north of the continent oil.
• On the deserted western coast, due to the climate, deposits were formed sodium nitrate.

The center of the continent (Amazonian lowland) is still poorly studied and developed.

The relief of South America is varied and contrasting. Based on the nature of the surface structure on the continent, two parts are distinguished. The greater eastern part is dominated by lowland, elevated plains and plateaus, while the longest mountain ranges of the Andes are in the west.

The lowland plains (Amazonian, Orinoco, La Plata) have a flat topography and are composed of marine and lacustrine-fluvial deposits. The relief of the western part of the continent is the result of the interaction of several lithospheric plates, at the boundaries of which mountain-building movements occur.

The formation of the Andes began in the Paleozoic and has not ended yet. The Andes continue to rise, volcanoes erupt, and strong earthquakes occur.

South America is rich in mineral deposits. The ancient shields of the platform contain the richest deposits of iron, manganese, nickel ores, uranium, and deposits of bauxite containing aluminum. Oil, natural gas, and coal were discovered in the depressions and troughs of the platform. Deposits of non-ferrous and rare metals have been found in the Andes. For example, the famous “tin belt” of Bolivia stretches from north to south for 940 km. The Andes are home to the world's largest deposits of copper ores, as well as molybdenum, silver, tungsten, lead and zinc ores. Sulfur, boron, iodine, and saltpeter are mined from non-metallic minerals on the Pacific coast and in the foothills of the Andes. There is oil in the intermountain basins.

South America is made up of two main geological elements: the Andes, a folded mountain belt in the east, and the South American mountain platform. Throughout its existence, the platform has been lowered and raised several times. Sedimentary rocks accumulated in subsided areas, and crystalline rocks in uplifted areas. Due to the different rates of uplift, the earth's crust cracked and lava splashed to the surface.

The continent, due to the peculiarities of its internal structure, can be divided into two parts:

1. Vast lowlands.

Landforms of South America

La Plata, Orinokska and Amazonian lowlands, located in the troughs of the South American platform, occupy almost half the area of ​​the continent.

2. Plateaus. In the east Guiana and the Brazilian plateau are formed by projections of the basement. In some places their height reaches 3000 m. The plateaus on the mainland are dotted with numerous river valleys, which can be seen if you look video in English.

Central part Guiana The plateau is notable for its huge flat-topped massifs, the walls of which are almost vertical. It is cut by abysses and deep canyons, but from a great height it seems that the surface is absolutely flat.

The Andes mountain system stretches along the Pacific coast, the average heights of which range from 3000 to 5000 m. The highest point is Mount Aconcagua (6960 m). These are young mountains, strong earthquakes and volcanisms are occurring here and now, resulting in the formation of the San Pedro and Cotopaxi.

Gold, uranium, aluminum, manganese, and iron ore are mined on the Guiana and Brazilian plateaus. The Andes are home to deposits of precious stones, zinc, lead and copper ores.

Thanks to the arid climate in the west of the South American continent, deposits of Chilean sulfur, which is a raw material for nitrogen fertilizer and iodine, have formed in dry reservoirs.

Volcanic phenomena in Andes contributed to the formation of deposits of building materials and sulfur. In the foothills and troughs of the platform in sedimentary deposits there are deposits of gas, oil, and coal. The largest oil fields are concentrated on the coast of the Caspian Sea and in the foothills of the Andes.

South America. PHYSICAL AND GEOGRAPHICAL POSITION.

The area of ​​the mainland is 17.8 million sq. km without islands and 18.3 million sq. km with islands. Extent from north to south -70 degrees. w.d. exceeds 7500 km, from west to east (in the widest part) more than 45oo km. South America in the northern part is crossed by the equator. The northernmost point is Cape Galinhas, 13 deg. N; southernmost continental point Cape Froward, 54 deg. S, Cape Horn Island, 56 deg. S The continent lies entirely in the Western Hemisphere. Westernmost point Cape Parinhas, 81 deg. w.d.; extreme eastern point of Cape Cabo Branco, 34 deg. w.d.

South America lies in the equatorial, two subequatorial, two tropical climate zones; the southern part is located in the subtropics and temperate zone.

The continent is connected to North America by the Isthmus of Panama and separated from it by the Panama Canal, and from Antarctica by the Drake Passage.

Geological structure and main landforms of South America

It is washed in the west by the Pacific Ocean, in the south by the Drake Irrigation, in the east by the Atlantic Ocean, and in the north by the Caribbean Sea of ​​the Atlantic Ocean. In the north there is the warm North Trade Wind Current, in the northeast - the warm Guiana Current, in the east - the warm Brazilian Current, in the southeast - the cold Falkland Current, in the south - the cold West Wind Current, in the west - the cold Peruvian Current, in the north -west - warm El Niño current. The coastline is slightly indented. Small bays are located at the mouths of rivers (La Plata, Maracaibo). Adjacent islands: in the north - the Lesser Antilles, in the southeast - the Falklands (Malvinas), in the south - Tierra del Fuego, in the southwest - the Chilean archipelago. The geographical position of the continent, mainly in low latitudes, determines the predominance of tropical types of landscapes - the “kingdom of tropical nature”.

TECTONIC STRUCTURE, RELIEF, MINERAL RESOURCES.

The relief of South America is asymmetrical. Most of the continent is occupied by vast plains of varying altitudes. In the west is one of the highest mountain systems in the world - the South American Cordillera (Andes). The average height of the continent is 580 m, the highest point is Mount Aconcagua 6960 m, the lowest is the Valdes Peninsula - 40 m. The relief features are determined by the tectonic structure. At the base of South America lies the ancient South American Platform with a Precambrian basement. Within the platform there are large shields in the north and east, which correspond to the Guiana and Brazilian plateaus. Powerful block processes occurred within the Guiana Plateau, which is why the plateau has a highly dissected topography. The highest point is Mount Roraima 2771 m, average heights range from 500 to 1000 m.

The Brazilian plateau corresponds to three shields: Southern Amazonian, Eastern Brazilian, Western Brazilian. This plateau rises gently from the north and northwest to the southeast. The highest point is Mount Bandeira 2890 m. Active magmatism occurred within this territory, traps and volcanic plateaus are found here. This territory is finished

its formation. Peneplains (leveling surfaces, denudation plains) are formed here.

Between the shields there are syneclises (deflections) of the platform foundation, which are filled with thick layers of sedimentary rocks. They correspond to the vast lowland plains of South America: Amazonian, La Plata, Orinoco.

In the west, the platform is adjacent to an area of ​​folding of Alpine age, which was formed in the Cenozoic as a result of the subduction of the Nazca plate and the South American lithospheric plate. This area of ​​folding corresponds to the Andes, which belong to the highest and highest mountains. The highest point is Mount Aconcagua 6960 m. Mountain building processes here have not yet been completed and are accompanied by earthquakes and volcanism (volcanoes Cotopaxi, Chimborazo). Tectonic processes are strong in the Caribbean, Northern and Southern Andes, calm in the Central and Patagonian Andes. The Andes are made up of parallel ridges. As they come closer, they form mountain nodes, and where the ridges diverge lie the Central Andean highlands and plateaus with an altitude of 3500-4000m.

South America has a huge mineral resource base. Ore deposits are confined to outcrops of the crystalline basement and to the Andean fold belt. Non-metallic - to the cover of sedimentary rocks of the platform. Significant deposits of iron (Minas Geras - Brazil), manganese, bauxite, titanium and uranium ores were formed in ancient igneous and metamorphic rocks and weathering crusts. Reserves of beryllium, niobium, zirconium, and tantalum are concentrated here. Vein deposits of gold and diamonds in Brazil play a significant role. On the Guiana Plateau there are large deposits of iron ore, bauxite and gold; large reserves of copper are concentrated in the Andean belt in Peru and Chile; in Bolivia there is a tin belt. Emeralds are mined in Colombia. In the sedimentary cover of the Orinoco, Amazonian and La Plata lowlands there are oil deposits, especially in Venezuela. 99% of the world's saltpeter reserves are concentrated in Atacama.

South America is the wettest continent on Earth, but not as hot as Africa, since the southern part lies in the temperate zone. Within the continent, an equatorial, two subequatorial, and two tropical climatic zones are formed; the southern part lies in the subtropics and temperate zone.

In general, the climate of South America is more varied than that of Africa and Australia. Average annual temperatures in most of the continent are from +20 to +28, and only in the south are these figures lower (from +8 in winter to + 16 in summer). The maximum recorded temperature is +46 (Cordoba), the minimum is -33 (Sariento). Antarctica has a huge influence on the climate of South America, from which the cold pampero wind blows into the temperate and even subtropical zones. In Patagonia, temperatures can drop to 0 in summer and -30 in winter; in the subtropics in the south of the Brazilian Plateau in summer up to +15, in winter up to +8.

The distribution of precipitation is extremely uneven, but the size of the precipitation layer is enormous - on average 1700 mm. The drainage layer into the hydrographic network is 700 mm. These values ​​are twice the earth's average. Maximum

the amount of precipitation falls in the western part of the Amazonian lowland (3000-4000 mm), on the western slopes of the equatorial Andes (up to 7000 mm) and on the western slopes of the Patagonian Andes (up to 4000-5000 mm). The minimum amount of precipitation is in the inland areas of the tropical zone, the south of the La Plata Lowland, and the barrier rain shadow zone in Patagonia. In general, the climate of South America, which is characterized by an abundance of warmth and light over most of the territory, creates favorable conditions for year-round plant growth.

INLAND WATERS.

Since South America is the wettest continent on Earth, one of the largest hydrographic networks in the world has formed here. South America covers 12% of the world's land area, but accounts for 36% of the world's ocean flow, 15% of which comes from the Amazon. The pattern of the hydrographic network is extremely asymmetrical, which is determined by the features of the relief. The main watershed runs along the tops of the Andes near the Pacific Ocean, so all the major rivers belong to the Atlantic Ocean basin (Amazon, Parana, Orinoco, San Francisco). Most of the rivers are fed by rain, and only the rivers of Patagonia and the Patagonian Andes are fed by snow and glaciers. The regime of rivers is determined by their position in climatic zones. For example, the rivers of the Amazon basin, which are fed by rain, are full of water throughout the year with two maximums in spring and autumn during the period of zenithal rains. Rivers of the subequatorial type are also fed by rain. These are major tributaries of the Amazon, Orinoco and Paraguay Rivers. They have maximum flow at the end of summer, beginning of autumn and winter low water. The rivers of the tropical zone in inland areas are low-flowing, but in the southeast of the Brazilian Plateau they are full-flowing throughout the year. Most of the rivers in the upper reaches are mountainous in nature, as they begin in the Andes and on the plateaus. There are an abundance of rapids and waterfalls. On the Guiana Plateau is the world's highest Angel Falls (1054 m). On the Iguazu River (Brazilian Plateau) is the world's longest Iguazu Falls (length about 3000 m, includes more than 270 cascades).

There are few large lakes. In the southern part of the Andes there are glacial lakes, in the north there is the lake-lagoon Maracaibo of tectonic origin, in the Central Andes at an altitude of 3800 m lies the largest alpine lake Titicaca with depths of up to 300 m.

Modern glaciation is relatively weak due to the high position of the snow line. Maximum glaciation in the Patagonian Andes and Tierra del Fuego.

NATURAL AREAS.

Due to its large extent from north to south, the continent has a clearly represented natural zonation from equatorial forests in the center to semi-deserts and temperate deserts in the south. Due to the predominance of a hot, humid climate on the mainland, forests are widespread here and there are relatively few deserts and semi-deserts.

1) The zone of moist equatorial forests (selva) is located on both sides of the equator in the Amazon basin, on the slopes of the Andes and in the north of the Pacific coast. The zone is formed within the equatorial and subequatorial climatic zones. Thanks to the processes of chemical weathering, fertile red-yellow ferralitic soils are formed in the jungle. Various types of palm trees, cocoa, hevea, many orchids, vines, melon tree, and ceiba grow here. Many animals are adapted to life in trees: prehensile-tailed monkeys, sloths, arboreal porcupines; Tapirs, anteaters, and jaguars also live here;

many species of parrots, hummingbirds; the world of insects is very rich; Snakes, including anacondas, are common. The forests have up to 12 tiers.

2) The zone of variable-humid equatorial forests is located north and south of the jungle, in the west of the Atlantic coast. It is formed within subequatorial climatic zones. Red soils and yellow soils are formed here. Vegetation and fauna are the same as in

3) The savannah zone occupies the Orinoco Lowland and most of the Guiana and Brazilian plateaus. It is located in the subequatorial climate zone. Red ferralitic and red-brown soils are formed here. Savannahs of the northern and southern hemispheres within the Southern

Americas are different. In the northern savannas (llanos), palm trees and acacias, mimosas, milkweeds, and bottle trees grow among the grasses. In the southern savannas (campos) the vegetation is poorer due to less rainfall: there are low-growing woodlands of Quebracho with very hard

wood. Animals in the savannas include small deer, wild peccary pigs, armadillos, anteaters, jaguars, pumas, and rhea ostriches.

4) The tropical desert zone occupies a small coastal strip on the west coast. Here, not far from the ocean, lies one of the most waterless deserts in the world - the Atacama. Cacti and thorny cushion-shaped bushes grow here and there on the rocky, infertile soils. On shore

There are bird colonies on the rocks.

5) The steppe zone (pampa) is located south of the savannas. In the hot tropical climate, fertile red ferralite soils were formed here. The main vegetation is grasses, among which feather grass, wild millet and other cereals predominate. In the southwest, where there is less

precipitation, there are thickets of thorny grasses and shrubs. Fast-running animals are typical for the pampas: pampas deer, pampas cat, several types of llamas. Lots of rodents (nutria, viscacha), as well as armadillos and birds.

6) The zone of semi-deserts and temperate deserts was formed in Patagonia in a temperate climate with little precipitation. The soils are poor brown and grey-brown. The vegetation is represented by dry grasses and cushion-shaped shrubs. The fauna is similar to the pampa, with rodents and burrowing animals living there. Among them are nutria and small armadillos.

7) Altitudinal zone.

In the equatorial zone: up to 1000 m - humid equatorial forests.

Up to 3000 m there are mountain and high-mountain forests where bamboo and tree ferns and cinchona are found.

Up to 4000 m - low trees and shrubs and woodlands appear. There are heather and myrtle thickets, and low-growing bamboos.

Above 4000 m there are alpine meadows (paramos). The vegetation consists of rare cereals and cushion-shaped shrubs. Flat areas have moss swamps, while large slopes are characterized by rocky, barren deserts.

Above 4500 m there are bare rocks, a belt of eternal ice.

In the subtropics, at the foot, there are deserts, turning into a belt of hard-leaved forests, extending to an altitude of 2000 m on the western slopes and up to 1800 m on the eastern slopes. Here you can find plane trees, glanders, and in the undergrowth there are thickets of flowering geraniums. Hard-leaved forests give way to deciduous beech forests, and above 2500 m there are mountain meadows.

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Tectonic map

At the base of the continent lies the South American Plate, so most of the terrain is plain. In the west there is an area of ​​new folding, where the relief is mountainous. The central and eastern parts are occupied by plains (lowlands, hills and plateaus), and the Andes mountains in the west.

The Andes are the longest (9000 km) and one of the highest (Mount Aconcagua, 6962 m) mountain systems on Earth, bordering all of South America from the north and west; southern part of the Cordillera. In some places, the Andes reach a width of over 500 km (the greatest width - up to 750 km - in the Central Andes, between 18° and 20° S). The average altitude is about 4000 m.

The relief of the eastern part was formed on the ancient South American platform. The rise of its foundation in relief corresponds to plateaus, and low-lying plains have formed in the troughs. The most powerful tectonic movements occurred on the shields; they are broken by cracks and there are faults. Erosion processes, weathering, and tectonic processes have created a wide variety of landforms on the Guiana and Brazilian plateaus.

The lowland plains (Amazonian, Orinoco, La Plata) have a flat topography and are composed of marine and lacustrine-fluvial deposits.

Features of the relief forms of South America

The relief of the western part of the continent is the result of the interaction of several lithospheric plates, at the boundaries of which mountain-building movements occur. The formation of the Andes began in the Paleozoic and has not ended yet. The Andes continue to rise, volcanoes erupt, and strong earthquakes occur.

Physiographic characteristics of the Interior Plains of South America.

The interior plains are located between the Brazilian Plateau and the Andes in the central part of the continent and are confined to three zones - subequatorial, tropical and subtropical. The Interior Plains includes five natural regions: Mamore, Pantanal, Gran Chaco, the interfluve of Parana and Uruguay, and Pampa.

Mamore Plains— flat alluvial plains . In summer, equatorial air masses bring heavy precipitation here, up to 2000 mm per year. In winter there is less rain, but the dry season is weakly expressed, so the composition of woody vegetation is closer to the hylae of the Amazon.

N variability of the Pantanal , dry in winter and flooded in summer with rainwater. It is composed of a thick layer of sedimentary rocks. The Pantanal plains are dominated by tall grasses and here and there trees and shrubs. Moisture-loving forests grow along the rivers.

Plains of the Gran Chaco. This is the hottest place in South America, the average January temperature is + 28, + 29 ° C, the absolute maximum is + 47 ° C. The alternation of the winter dry and summer rainy seasons is well defined in the region. Precipitation is predominantly rainfall. On the western, more elevated part of the region, there are forests of prickly acacias, cacti, and agaves; areas of steppes and forests appear to the east. In wetter places the wax palm grows. In the north of the region there are extensive wetlands.

Interfluve of Parana and Uruguay It is a plain up to 100 m high. The climate here is subtropical, humid, with an even distribution of precipitation over the seasons, with over 1000 mm falling during the year. The northern part is swampy; the center and south of the interfluve are a well-drained, slightly hilly plain, composed of sandstones covered with marls. The black-colored soils of subtropical savannas are well developed; forests of mimosa and acacia grow here. There are areas of subtropical steppes.

The southern part of the Interior Plains is occupied by Pampa - grassy plains. The climate of Pampa is subtropical. The average temperature in January is + 22 - + 24° C, in July + 7 - + 9° C; precipitation falls 1000-1200 mm per year, it is distributed evenly across the seasons.

In the flora of Pampa there are up to a thousand species of different cereals. There are areas devoid of grass. On the clayey soils of Pampa, the grass silvery gynerium is present. The fauna of Pampa is not rich and monotonous. Vizcacha, a large rodent, is often found. Rare predators (puma). Typical birds are the ibis, ipikaha, and tinamous, which are similar in size and appearance to a partridge.

44. Precordillera and Pampinsky Sierras (physiographic characteristics).

Precordillera - Characterized by great contrasts in relief, climate, soil and vegetation cover. Against the background of elevated plains, steep mountain ranges with a height of 2500-4000 m often rise here. They are composed of Precambrian and Paleozoic rocks, and were subjected to long-term destruction and leveling. Between the mountain ranges, wide valleys formed - bolsons and depressions (Salinas Grande).

The Precordillera is characterized by a continental arid climate. Precipitation falls unevenly. The amount of precipitation decreases from east to west, with the eastern slopes of the mountain ranges receiving more precipitation than the western ones. The river network is poorly developed. A large area is occupied by salt marshes.

The vegetation has a xerophytic appearance; shrub formations of the Monte type are widespread. At an altitude of 500-1000 m, the remains of subtropical forests with hard-leaved evergreen trees and shrubs have been preserved. Above 2500 m the mountain cereal steppe begins.

To the south the forests become thinner. In the southwest, large areas are occupied by semi-deserts with gray soils and salt marshes.

The southeastern part of the Precordillera is occupied by Patagonia. The surface of this natural area is a stepped plateau composed of Meso-Cenozoic deposits. Lowlands are found only in the northeast and southeast. Patagonia's position in temperate latitudes in the western transport zone, between two oceans, should have led to a mild climate and good development of the hydraulic network. The main reason for the aridity of Patagonia is that the prevailing westerly winds in these latitudes carry moist sea air from the Pacific Ocean and encounter the Andes mountain barrier. The annual precipitation in Patagonia is 120 - 200 mm. The vegetation cover is dominated by cushion-shaped and creeping forms of shrubs with pronounced xeromorphism; there are few trees. Among the cereals there are plentiful thorny, inconspicuous bushes of harilla, dense cushions of bolax and azorella; southern species of cacti are found.

Among the endemic representatives of the fauna of Patagonia, we should note the Zorillo skunk, the fox-like Magellan's dog, and the Darwin ostrich (the southern species of rhea). Rodents (mara, tuco-tuco, etc.) are also typical, and the Pampas cat and armadillos are also found.

46. ​​Northern Andes (physiographic characteristics).

The mountain ranges of the Northern Andes, dissected by river valleys, stretch from the shores of the Caribbean Sea to 5° south. w. The Northern Andes include the Caribbean Andes, located along the coast of the Caribbean Sea, the Northwest Andes (the Andes of Colombia and Venezuela) and the Andes of Ecuador.

Caribbean Andes Unlike other parts of the mountain system, they have a latitudinal strike. These are the northernmost and youngest ranges, they are more arid than the nearby plains. The mountains are almost devoid of forest cover. The main folding formations in the Caribbean Andes occurred in the Pliocene, when two main anticlinal folds arose - the Coastal and Inner Cordillera. They are separated by a longitudinal depression, now occupied by lacustrine alluvial deposits. The Caribbean Andes have a distinct winter dry season. The lower belt of the mountains is represented by summer-green open forests or thorny shrubs (chaparro) growing on red-brown soils. Higher up, with decreasing temperatures, precipitation becomes greater, so the forests are denser, and evergreens appear at an altitude of 1500-1600 m.

North of the Caribbean Andes are located Caribbean lowlands composed of alluvium. Lake Maracaibo once occupied the entire lowland; now its area is shrinking due to filling with alluvial sediments. At the same time, coastal areas are experiencing gradual subsidence.

The second tectonic trough is occupied by the lowlands of the Magdalena and Cauca rivers, composed of alluvium and coarse clastic material demolished from the Andes mountain ranges Northwestern Andes- the most branched and complexly constructed part of the Andean mountain system. They are located mainly in Colombia. Three main ridges are well defined here - the Western, Central and Eastern Cordillera with a height of more than 5000 m. Among the mountain peaks there are many extinct and active volcanoes. The Central Cordillera reaches the highest average height (Hila volcano, 5750 m, Ruiz peak, 5400 m). The Western and Eastern Cordillera are lower; the latter is divided in the north into two ranges (Sierra de Mérida and Sierra de Perija), covering the lowland of Maracaibo. Between the Eastern and Central Cordillera there is a valley of the Magdalena River - a graben filled with a thick layer of Cretaceous and Cenozoic sediments. To the north-west along the coast of the Pacific Ocean stretches the low Sierra de Baudo, composed of Cretaceous and Tertiary tuffaceous strata.

The Northwestern Andes are located in a subequatorial and equatorial climate. In the direction from north to south, the duration of the dry period gradually decreases, which is practically absent south of Bogota. Mountain ranges in general are abundantly moistened, and on the Pacific coast, due to local circulation and orographic conditions, the amount of precipitation reaches 8000 m (the highest amount in South America). Inland areas are less moistened, but aridity is not pronounced. Climatic features are also reflected in the zonation of soil and vegetation cover. In the west, on the Pacific coast and the slopes of the Sierra de Baudo ridge, a dense mountain hylea is formed. To the east, the amount of precipitation decreases, so the lower parts of the slopes are covered with summer-green open forests and shrubs, higher up - with mixed, deciduous-evergreen forests, and only at an altitude of 1000 m does wet mountain hylea begin. Here you can find the toquilla palm, balsa wood with very light wood, and a number of wood species typical of the Amazon. The avifauna is richly represented - up to 1500 species. Parrots, hummingbirds, and sunbirds are typical.

Higher up, as the temperature decreases, belts of open forests and crooked forests appear; at an altitude of 2500-3500 m, the mountain meadows of paramos extend.

Geological structure, relief, minerals of South America

Even higher up there are peculiar associations of uplands of herbaceous vegetation with individual shrubs and cacti. The interior slopes of the northwestern Andes are drier. Hard-leaved or summer-green forests grow here.

Andes of Ecuador(from 2° N to 5° S) - the narrowest part of the Andes, high-mountain and tectonically active. Two parallel chains are well defined in them - the Eastern Cordillera and the Western Cordillera, separated by a number of intermountain basins. The total width of the mountain system here is about 90 km. The ridges consist of separate mountain ranges, separated by saddles that are poorly defined in relief. The main peaks are, as a rule, active and extinct volcanoes, including the highest of them, the Chimborazo volcano (6267 m). The active volcanoes of Cotopaxi, Antisana, and Sangay are known. Intermountain basins are located at an altitude of 2500-2800 m, they are filled with a layer of volcanic ash, tuff and alluvium. The epicenters of earthquakes are most often located in the area of ​​the intermountain valley separating these Cordillera chains.

To the west of the Andes mountain range lies a strip of the Costa coastal plain, with a hot and humid climate. Here there is a rapid decrease in precipitation from 1200-1500 mm in the northern part (with high relative humidity) to 400 mm in the south. These changes are reflected in the vegetation cover. Savannas with areas of wet equatorial forests, occupying the northern part of the Costa, are gradually replaced to the south by dry steppe vegetation. In the mountainous part, vertical zonality is well defined. Up to 800-1000 m, the change in climate and vegetation cover is still weakly felt, then the amount of precipitation increases noticeably, the amplitude of temperatures decreases with a general decrease. Cinchona, balsa, and ceiba trees appear in this belt. From an altitude of 1500-1800 m, palm trees disappear, and tree ferns become more numerous. Above 3000 m, vegetation of the paramos type predominates on mountain meadow and mountain steppe soils. Eternal snow begins at an altitude of 4200-4500 m. The mountain climate is more favorable for human life than the climate of Costa and Gil.