The message on the topic of the relief of South America is brief. Features of the relief of South America
15. General features of the relief South America. Mineral resources of the continent and their confinement to geological structures.
Most of South America is occupied by plains : Orinokskaya,Amazonian and La Plata lowlands, the Brazilian and Guiana plateaus and the Patagonian plateau. The location of the plains in the eastern part of South America is explained by the location of the ancient South American platform in this part of the mainland. In this part of the mainland there are the most important deposits of oil (Orinok lowland), natural gas (Patagonia and Tierra del Fuego), iron, manganese, chromium, aluminum, nickel, uranium ores, gold and diamonds (Brazilian and Guiana plateaus). In the southeast of South America, there is the lowest point on the mainland - the Salinas Chicas depression (-42 m). In the west of South America along the entire Pacific coast are located areas of young Alpine (Cenozoic) folding. In relief, they are represented by the high Andes mountains, the highest point of which is Mount Aconcagua - 6960 m. Active seismic and volcanic activity is associated with young folding (volcanoes of Cotopaxi, Lullaillaco, San Pedro and others). The Andes are rich in non-ferrous metal ores: copper, tin, polymetallic, silver, gold and platinum, as well as iron ores and saltpeter. In the foredeeps at the foot of the Andes there are deposits of oil, natural gas and coal.
The relief of South America is varied. According to the nature of the geological structure and features of the modern relief, South America is divided into two heterogeneous parts. The eastern part of the mainland is the ancient South American platform; western - actively developing folded belt of the Andes. The elevated sections of the platform - shields - correspond in relief to the Brazilian and Guiana plateaus . The troughs of the South American platform correspond to the giant lowland plains - the Amazonian, Orinoc, the system of internal plains (the Gran Chaco plain, the Laplata lowland), and the young Patagonian platform - the plains of Patagonia. The Amazonian lowland is filled with marine and continental sediments. It was formed as a result of the activity of the Amazon River, as a result of the accumulation of sediments brought by the course. In the west, the lowland is very flat, the river valleys are slightly incised, the heights barely reach 150 m. Its northern and southern margins, underlain by crystalline rocks of the shields, are elevated and gradually turn into plateaus. The Brazilian Plateau is located in the east of the mainland. It is a ledge of the crystalline basement of the platform, between which there are troughs filled with sedimentary rocks and volcanic lavas. This is the largest rise within the platform. The Brazilian plateau has heights from 250-300 m in the north to 800-900 m in the southeast. The relief of the plateau is a relatively leveled surface, above which blocky massifs and plateaus rise. In the north of the mainland, the Guiana Plateau (300-400 m) is confined to the vast ledge of the folded base of the platform. Its relief is dominated by stepped plateaus. The vast plains and large sections of the plateaus of South America are convenient for the life and economic activity of the population. (Show on the map the largest lowlands and plateaus and determine their maximum heights.)
The Andes is the longest mountain range on land with a length of 9000 km. The Andes are one of the highest mountain ranges in the world. In height, it is second only to the Tibetan-Himalayan mountainous country. Twenty peaks of the Andes rise to a height of more than 6 thousand meters. The highest of them is the city of Aconcagua (6960 m) (Fig. 86). The formation of the Andes is the result of the interaction of two lithospheric plates, when the oceanic Nazca plate “dived” under the continental South American one. At the same time, the edge of the continental plate was crumpled into folds, forming mountains. Currently, mountain building continues. This is evidenced by the eruptions of numerous volcanoes and the strongest catastrophic earthquakes. Among the large volcanoes, one can note such as Chimborazo (6267 m), Cotopaxi (5897 m). The west coast, occupied by the Andes, belongs to the Pacific "Ring of Fire". The world's strongest recorded earthquake of 11-12 points occurred in 1960 in Chile. In 2010, an earthquake in Chile claimed several hundred lives. Serious disasters occur in the Andes every 10-15 years. The Andes mountain system consists of several meridianally elongated mountain ranges. Between the ridges lie internal plateaus and plateaus, with a height of 3500 to 4500 m.
Minerals. The mainland is rich in minerals. richest deposits of iron and manganese ores are confined to ancient shields South American platform: to the center and outskirts of the Brazilian Plateau, as well as to the north of the Guiana Plateau. The largest mining area iron ore is Carajas. In the northern part, on the outskirts of both plateaus, there are very large deposits of bauxite, a raw material for the aluminum industry. Bauxites occur at shallow depths and are mined by open pit mining. Ores of copper (Peru, Chile), tin (Bolivia), lead and zinc (Peru) have been explored in the Andes. The foothills of the Andes, especially Venezuela and Colombia, are rich in oil and natural gas. Coal deposits are less significant (Ecuador, Argentina). Many Andean countries are famous for their mining of precious stones. First of all, this applies to the extraction of emeralds in Colombia. Of the precious metals in South America, the largest reserves of silver are in Peru. The Andes belt is also famous for some non-metallic minerals. Saltpeter occupies the first place among them. The famous Chilean saltpeter and iodine are mined in the dried-up reservoirs of the Atacama. The relief of South America is more diverse in comparison with Africa and Australia. The high Andes in the west separate the main flat part of the mainland from the Pacific Ocean. South America is characterized by active seismicity. South America is called the "pantry of the world." The mainland is rich in natural resources necessary for the development of many sectors of the economy
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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 of 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. the extreme southern point of the 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
- And why is it necessary to know the geographical position of the 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, Orinoco, 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 highest 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 evaluates 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 the 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
Check of knowledge. 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) an area of South America where catastrophic earthquakes occur?
C) an oil-rich plain?
D) highlands rich in gold and diamonds?
E) a highland that gradually descends to the northwest?
E) highlands, which are characterized by the highest heights in the central part?
G) mountains, the name of which is in the language local residents 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.
Target: form an idea of the features of the relief, tectonic structure and minerals of South America, to continue to form the ability to compare maps of the atlas with different content, to develop curiosity and interest in geography.
Tasks:
- check the knowledge gained in the study of the topic “ Geographical position South America”
- find out the features of the relief of South America;
- find out the patterns of placement of large landforms, tectonics and minerals;
- execute practical work №18.
Equipment: Wall maps “Physical map of South America”, “The structure of the Earth's crust”, a set of diagrams “Relief of South America”, cards for checking homework.
Lesson type- combined.
Plan - lesson summary
1. Introduction
1 Class organization
2 Announcement of the topic.
3 Checking homework
Crossword "South America" (Slide 1)
1 What is the name of the extreme western point of South America (Pariñas). (Slide 2)
2 What current runs along the western coast of South America (Peruvian). (Slide 3)
3 Which ocean washes South America from the east. (Atlantic) (Slide 4)
4 What part of the world does South America (America) belong to (Slide 5)
5 Name the extreme northern point of Young America (Gallinas) (Slide 6)
6 What is the largest island located south of South America (Tierra del Fuego) (Slide 7)
7 What strait separates the mainland of South America and the island of Tierra del Fuego (Magellan) (Slide 8)
8 Russian botanist who, during his expedition to the mainland, established the geographical centers of the ancient centers of agriculture and the origin of some cultivated plants, whose homeland is South America (N.I. Vavilov) (Slide 9)
9 The traveler who discovered America in 1492 (H. Columbus) (Slide 10)
10 In the 15th century, he was the first to suggest the existence of a new continent. Following his colorful descriptions of distant lands, the Spanish and Portuguese conquerors (Amerigo Vespucci) rushed to America (Slide 11)
4 Assimilation of new knowledge
1) Announcement of the topic of the lesson, setting tasks (Slide 12, 13)
The relief is a set of irregularities of the earth's surface, differing in size, origin and age. (Slide 14) The relief has a great influence on the formation, development and placement of all components of nature on the surface of the mainland. Therefore, knowledge of the relief is simply necessary when studying the mainland.
In the relief of South America, as you already know, there are similarities with Africa and Australia and there are differences.
What are the features of the relief of South America?
Working with the physical map of South America
What landforms prevail on the mainland.
How are the landforms located in the study area;
What are the greatest and predominant heights. (Slide 15)
Anchoring
Scheme on the board and in a notebook
Thus, we see with you that the relief of South America is diverse: a combination of high mountains and plains of various heights; large fluctuations in altitude; There are two parts: the mountainous West and the flat East. (Slide 18)
A moment of relaxation “Geo-focus”(Slide 19)
Why do mountains dominate in the west of the mainland, and plains and plateaus in the east? (Slide 20)
To do this, we will consider a map of the "structure of the earth's crust"
By " physical map South America "and the map" Structures of the earth's crust "establish links between the structure of the earth's crust and the location of the main landforms. Based on the comparison, enter the results of the analysis of the cards in the table (Slide 21, 22)
The dependence of the relief on the structure of the earth's crust
landform name | Tectonic structure | Minerals |
G. Andes | Area of new folding (the area of collision of the oceanic and continental crust) |
Copper ores, gold, polymetallic ores, nickel ores, molybdenum ores, tungsten ores. |
brazilian plateau | South American platform | Iron manganese, nickel ores |
Guiana Plateau | South American platform | Iron, manganese ores |
Amazonian lowland | South American platform | Oil, natural gas, coal |
Orinok Lowland | South American platform | Oil, natural gas |
La Plata lowland | South American platform | Oil, natural gas |
What landforms mostly correspond to the ancient platforms? - Which - folded areas
Why are the mountains of South America high?
Which indicates the formation of the Andes mountains at the present time.
Why do minerals have such an arrangement on the mainland of South America.
Conclusion:
- the location of large landforms depends on the tectonic structure;
- placement of ore and non-metallic minerals are confined to a specific tectonic structure. (Slide 23)
5 Fixing
Practical work No. 18* Designation on the map of large landforms and mineral deposits.
Target:
- Get to know the location of the main landforms of South America
- Mark large landforms and mineral deposits on the map. Determination of similarities and differences in the relief of Africa and South America
Progress
1 Mark and sign on the contour map of South America large landforms:
a) plains: Amazonian, La Plata, Orinokskaya;
b) plateau: Brazilian;
c) Mountains: Andes;
d) peaks: Aconcagua, Cotapaxi volcano
2 Designate mineral deposits using conventional signs
6 Homework (Slide 25)
- paragraph 41, questions 1-4;
- learn the nomenclature on the topic “Relief of South America”
Features of the geological structure of 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, a clear difference between the eastern and central parts from 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 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 is a flat area with absolute altitudes 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 of hilly plains, low massifs cut by gorges.
Minerals
The distribution of minerals is also associated with the geological structure.
- Deposits are located on ancient shields iron, manganese, uranium ores, bauxites, diamonds.
- The Andes, justifying their name, are famous copper ores, deposits gold.
- Large deposits discovered in the north of the mainland 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 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. In the south, in Patagonia, an ancient platform is connected to a young Epipaleozoic platform with flat relief. 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 oldest (Early Precambrian) igneous and metamorphic rocks that come to the surface in shields - Guiana, South Brazilian, West Brazilian.
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 occupies an area of 5 million km°, is extremely monotonous. 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 mountain system land, stretching for almost 9000 km, with an average height 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 periods. 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 6 ° N. sh. and 2°S latitude, from 15° to 29° S sh. and between 33-52° S. sh. There are three main mountain ranges in the Andes: 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 28°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, intermountain valleys flow major rivers Magdalena, Kauki, Atrato, etc. In the Chilean-Argentinean Andes, a large tectonic depression of the Longitudinal Valley is distinguished.