Relief of North America
The western part of the mainland is mountain system The Cordillera, the highest point of which is Mount McKinley (6193 m), the eastern one - vast plains, plateaus, medium-altitude mountains. In the northeast of North America - the Laurentian Upland. The hinterland is the (high) Great Plains and the (low) Central Plains. The central, large, part of North America is occupied by the Precambrian North American (Canadian) platform. The eastern edge of the mainland is bordered by mountain uplifts of the Canadian Arctic Archipelago, Labrador, and the Appalachians. Along the southeast coast there are coastal lowlands - the Atlantic and the Mexican.
Relief of South America
The western part of South America is occupied by the vast Andes mountain belt, the central and eastern parts are lowlands and plateaus on the Precambrian South American platform. However, unlike North America, South America is a very warm continent. The equator crosses it almost in the middle, and therefore landscapes of the equatorial, subequatorial and tropical zones are developed in the predominant part of the territory. The asymmetry inherent in the relief manifests itself both in climatic conditions and in river network, and in the location natural areas. Humid and warm air masses coming from the Atlantic Ocean dominate the northern and central regions of the Out-Andean East, and therefore the most humid landscapes are located in the east. In the wide northern part of the mainland is one of the largest lowlands on the planet - the Amazon. The Amazon River originates in the Andes, not far from the Pacific coast, and flows east across the mainland, flowing into Atlantic Ocean. In this part of the mainland there are other large river systems - the Parana and Orinoco rivers.
The Andes is a complex mountain system that stretches along the entire western coast of South America. Almost throughout the Andes, they consist of parallel, very high (up to 6000 m) folded ridges - the Eastern, Central, Western and Coastal Cordilleras, between which there are lower sections - intermountain basins, sometimes narrow, sometimes expanding in the form of plateaus.
The high-mountainous Central Andean Highlands (Pune) is a vast area of low relief, squeezed on all sides by high, more than 6000 m, ridges of the Andes. The average height of Pune exceeds 4000 - 4600 m, and the width is about 600 km. Sections of volcanic plateaus alternate with flat plains (Altiplano), which represent the bottom of the former giant lake. Its remnants are Lake Titicaca at an altitude of 3812 m (the greatest of the alpine lakes in the world) with a depth of up to 304 m and Lake Poopo.
To the north of the Amazonian lowland is the Guiana Plateau up to 3014 m high. To the south of the Amazonian lowland, the surface rises again. Here, on the ledge of the South American platform, the Brazilian plateau was formed up to 2890 m high. Its relief is very heterogeneous - from almost table-like plateaus in the center to high flat-topped mountains in the east.
To the south of the Brazilian Highlands stretches the wide Laplat lowland, along which the Parana River flows.
Geography Grade 7
Lesson topic: Relief and minerals of mainland South America
The date of the…………….
Lesson Objectives: To continue the formation of students' ideas about the nature of South America; to recall already known and to disassemble with students new terms and concepts; to form their ideas about the tectonic structure, relief and minerals of South America - their composition, origin, structure; to introduce students to the objects of the relief of South America; continue the formation of the ability to establish causal relationships, comparing various geographic Maps.
Equipment: building map earth's crust, physical map South America, wall contour map.
During the classes
Checking the knowledge gained in the last lesson. Without using maps, 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.
| Statements | |
| 1. this continent crosses the equator in its northern part | |
| 2. The area of the mainland is 18 million square meters. km. | |
| 3. The mainland is washed by the waters of the Indian Ocean. | |
| 4. separated from the mainland North America Panama Canal. | |
| 5. the coldest continent on earth. | |
| 6. extreme south point mainland - Cape Agulhas (35S 20E) | |
| 7. is separated from the mainland Antarctica by the Mozambique Channel. | |
| 8. This continent is like a bunch of grapes. | |
| 9. in the south of the mainland is the island of Tasmania. | |
| 10. In the north, the mainland is washed by the waters of the Caribbean Sea. | |
| 11. This continent is washed by the waters of two oceans. | |
| 12. refers to one part of the world. | |
| 13. lies entirely in the western hemisphere. | |
| 14. is located in both the western and eastern hemispheres. |
Justification for incorrect answers ______________________________________________
Reflection
- Why do you need to know geographical position mainland?
I - setting the cognitive task of the lesson
1. Terms and concepts. Choose those that you already know and write them in the first column.
Platform, young mountains, shield, foundation, lowland, plateau, plateau, Amazonian, Brazilian, Orinocian, La Platskaya, Andes, graben, Aconcagua, Cotopaxi.
Ask students to complete the table
2. Reflection. We check what is written in the column "I want to know." We are looking for these concepts on the map of South America. Setting the cognitive task of the lesson. To study the features of the relief of South America.
3. Make a cluster on the topic "Relief of South America". Arrange arrows that show the relationship between the relief and its diversity.
4. Work in groups on the characteristics of one of the forms of relief according to the plan, which the students draw up on their own. Each group posts. Such landforms are characterized as: Andes, Amazonian lowland,
Orinoco Lowland, Brazilian Plateau, etc.
5. Checking the knowledge gained while studying the topic of the relief of South America.
1. Why is it necessary to study the relief of the territory?
2. What cards should be used?
3. Why are mountains located in the western part of the mainland?
4. Find the best high mountain?
5. What volcanoes are there in the Andes?
6. What is the dependence of the relief on the structure of the earth's crust?
6. Work in groups on the definition of minerals.
One group assesses the minerals located in the Andes mountains, the other on the Brazilian plateau, and the third on the lowlands.
The dependence of types of minerals on the structure of the earth's crust is revealed.
Identification of causal relationships(filling in the systematizing table)
Using the maps of the atlas, fill out a systematizing table and, based on a comparison of the relief, structure and minerals in the Andes mountains, the Brazilian plateau and the Amazonian lowland, identify cause-and-effect relationships
Knowledge check. Digital dictation "Surface Shapes of South America".
1. Orinok lowland
2. Amazonian lowland
3 Brazilian Flathorn
4. Guiana Highlands
5. Andes Mountains
What is the name of:
A) the greatest plain the globe?
B) the area of South America where they are catastrophic earthquakes?
B) plain oil rich?
D) highlands rich in gold and diamonds?
E) a highland that gradually descends to the northwest?
E) highlands, which are characterized greatest heights in the central area?
G) mountains whose name in the language of the locals means "copper"?
Students check the spelling for correctness.
Homework: draw up a route for a geologist on the mainland of South America. Assess mining conditions.
Peculiarities geological structure South America
An ancient supercontinent existed millions of years ago gondwana . It broke up into three large blocks of the 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, there is a clear difference between the eastern and central parts and the western part of the continent. The east and center of the mainland are located on the old Precambrian South American platform . In the north and east of the platform, there are extensive areas where the ancient crystalline foundation of the platform comes to the surface - Guianan and Brazilian shields . The western part of the mainland is represented folded area , formed as a result of the collision of the continental platform and the oceanic lithospheric plate.
The oceanic plate sags and goes under the continental, forming a deep Peruvian trough (trough) along the entire west coast.
The edge of the continental plate is crumpled into folds. Mountains rose along the entire western edge of the mainland. This is a young area Cenozoic folding . This is evidenced by volcanic eruptions and frequent earthquakes. Goes active process 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 mainland in the past experienced repeated subsidence and uplift. This is evidenced by sedimentary rocks including - marine sediments.
At present, erosion processes, intensified by economic activity person.
Features of the relief of South America
The folded region in the west of South America forms one of the largest mountain systems on the planet - andes mountains . In Indian language it means "copper mountains" .
The Andes mountains stretch along the coast Pacific Ocean three parallel mountain ranges. Many peaks rise above $6000$ m above sea level.
Highest point 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 the plain with absolute heights up to $200$ m.
Definition 2
Plateau - this is a section of the plain with absolute heights - more than $ 500 $ m.
The lowlands of South America are Orinoc, Amazon and La Plata . The elevation difference here is negligible. These are almost flat plains.
Remark 1
Amazonian lowland - the largest lowland in the world.
Thanks to marine deposits, 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 were accompanied by breaks in the earth's crust, lava outcrops. In some places, the relief of the plateaus has the appearance of table mountains. They are replaced by landscapes rolling plains, low massifs, indented by gorges.
Minerals
The distribution of minerals is also associated with the geological structure.
- Deposits are located on ancient shields iron, manganese, uranium ores, bauxite, diamond.
- The Andes, justifying their name, are famous copper ores, deposits gold.
- Found in the north of the mainland large deposits oil.
- On the desert west coast, due to the peculiarities of the climate, deposits were formed sodium nitrate.
The center of the mainland (Amazon lowland) is still poorly studied and developed.
South America has different character geological structure, which is associated with the formation of the earth's crust in different archaeological periods. East End formed in the Precambrian period, and there the relief of South America is a plain - this is the South American platform. The West has been actively formed since the Paleozoic period and the Andes are located there.
Plains of South America
The flat platform has deflections and raised areas. In place of the first (also called "shields"), two highlands are located - Brazilian and Guiana. During the period when they were rising, the slopes became almost vertical. The part of the Brazilian Highlands in the east, where the sierras formed, rose the most. At 2890 meters above sea level, there is the highest point of the highlands - the Bandeira massif.
Rice. 1. The relief of South America.
As for the deflections, there are three plains huge scale- La Platskaya, Orinokskaya, and also Amazonian.
The relief and minerals of South America are closely related to its geological history. Thus, the ancient shields of the platform are the richest in iron ore - these are the Brazilian (center and outskirts) and Guiana (north) highlands. In the highlands, there are rich reserves of bauxites containing aluminum) and manganese. Where the platform sags, there are oil reserves and the accompanying natural gas, as well as a stone corner. Venezuela can rightfully be considered the leader in the production of "black gold" and gas. These facts are necessarily noted in the textbook for grade 7.
Rice. 2. Brazilian Highlands.
Uranium, titanium, nickel, and zirconium have been found where igneous rocks lie close to the surface or have even flowed onto it.
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South America contains 38% of the total iron ore on the planet.
Mountainous part of South America
The mountainous part of South America is called the English West, and it is located in the west.
The Andes chain is one of the highest on Earth. If we compare the relief of Africa and South America, then one of the differences will be due to these mountains: when glaciers descended from their peaks, they “cut” the coast, which is not observed on the African mainland.
There are twenty peaks in the Andes, whose height exceeds 6 thousand meters above sea level. And the highest point of the chain is Mount Anoncagua. It is located in the Chilean-Argentine part of the mountain range and rises to 6960 meters. At the same time, the total length of the entire mountain chain is almost nine thousand kilometers, which makes it the longest on Earth.
Rice. 3. Andes.
The Andes began to form during the Paleozoic, in the Hercynian folding, but the Alpine became the main period for them. In the Cretaceous period, the result of folding was the Western Cordillera (Colombia-Tierra del Fuego). But the features of the relief of the Central Andes are associated with the Alpine orthogenesis, when the ancient Hercynian structures were broken and partially raised. This is how the main high mountain plateau was formed.
The Andes continue to form into the modern period. This is evidenced strongest earthquakes(the last of which happened less than half a century ago, in 1970 in Peru). Earthquake epicenters are confined to the Peru Trench, which stretches along the western coast of the mainland. Tsunamis are the result of earthquakes. The highest of now active volcano in this part of the world - Lullaillaco, his brothers Osorno, San Pedro, Cotopaxi, Ruiz also do not sleep.
Thus, in the western part, the prevailing landforms determine the presence of the corresponding minerals. Ores of metamorphic and magmatic origin are located in the Andes in rich deposits. Gems and non-ferrous metals, considered rare, are also found in these places in significant quantities. Thus, Chile ranks second in the world ranking of countries producing copper and molybdenum ore, and tin reserves in Bolivia are regarded by experts as significant. This is not to mention Colombia, the “land of emeralds”. In addition to the above minerals, the western part of South America has reserves of gold, zinc and platinum, as well as antimony, silver, lead and tungsten. Many of them began to develop even the ancient Incas, who even named one of the lakes of Titicaca, that is, “lead rock”.
Chile is rich in saltpeter deposits, which are formed from seabird droppings through biochemical decomposition. The main factor in their formation was the desert climate.
What have we learned?
We received a description of the relief of South America with reference to the historical periods of its formation, and also learned that certain part the mainland continues to form. The formation process is manifested by earthquakes and volcanic eruptions. We figured out how the origin of landforms affects what minerals are common in a particular region and learned Interesting Facts about it. In addition, we received information about the main plains of South America and the Andes mountain range, and also about the features of the continental relief and the distribution of resources.
Topic quiz
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South America has a fairly simple orotectonic structure. A large, western, part of the mainland is located on the South American platform, part of the South American lithospheric plate. To the south, in Patagonia, an ancient platform is connected to a young flat-topped Epipaleozoic platform. These are flat territories with different altitudinal characteristics from lowlands to plateaus. In the west of the mainland there is an area of alpine folding represented in the relief by the longest mountain range of the Earth - the Andes.
Out-Andean East
Located on the South American Platform. Its uplifts are expressed in relief by plateaus (Guiana and Brazilian), and troughs - by lowlands (Amazonian, Orinocskaya, La Plata) and uplands (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, West Brazilian shields.
Tectonic movements broke up the plateaus, in particular the Brazilian one, into separate blocky massifs. Outpourings of basalts formed in the southern part of the Brazilian Plateau the Parana lava plateau, the largest on Earth.
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. In it, uplifts and subsidence often alternate with sedimentary strata crumpled into short gentle folds.
The relief of the low plains is extremely monotonous. They formed in the syneclises of the South American platform plate, which was gradually filled with sedimentary deposits. The relief of the Amazonian lowland, which covers an area of 5 million square meters, is extremely monotonous. km. Even at the foot of the Andes, the height in the Amazon Valley is only 150 m above sea level. seas. In the less extensive Orinok lowland and on the Inner Plains, the areas closest to the Andes are usually elevated due to the removal of abundant sediments from the mountains and lowered to the axes of the troughs, emphasized by the course of the main rivers - Orinoco, Mamore, Paraguay, Parana; the swampy La Plata lowland stretches along the latter.
Andean West.
Andes - the greatest land mountain system, stretching for almost 9000 km, with average heights of 4-5 thousand m. The highest point - Mount Aconcagua rises to 6960 m. The Andes is a fragment of the Pacific Ring of Fire (Pacific belt of lithospheric compression). The main phase of mountain building took place at the end of the Cretaceous - the beginning of the Paleogene. Since the Cretaceous period, the Andes have been characterized by strong volcanic activity. Along the lines of splits and faults in the Andes, numerous cones of volcanoes were formed, concentrated in three main areas: between 60 s. sh. and 20 ju. sh., from 15030 / to 290 s. sh. and between 33-520 S. sh. In the Andes, three main mountain range: Cordillera East, Cordillera Central and Cordillera West. Also, in some areas, the low Coastal Cordillera is most often expressed. Intermountain plateaus Puna (Punas) and Altiplano appear in the Central Andes. South of 280 s. sh. the Eastern and Central Cordillera disappear and the Western Cordillera becomes the main one, and south of 42 ° S. sh. The coastal Cordillera turns into a system of islands (Chinos, Chiloe). In the Colombian Andes, the large rivers Magdalena, Cauchi, Atrato, and others flow through the intermountain valleys. In the Chilean-Argentinean Andes, a large tectonic depression of the Longitudinal Valley is distinguished.