South America: Geography and Climate. Features of the relief of South America

There are some similarities with North America in the orography of South America. On the east, along the shores of the Atlantic Ocean there are vast highlands: Brazilian, Guiana and Patagonian. In the extreme west and north of the continent, repeating the outlines of its coasts, stretches for 9 thousand km the longest mountain system in the world - the Andes, or the South American Cordilleras. Between the highlands and the Andes, there are vast low-lying plains that occupy about 45% of the mainland: Amazonian, Orinokskaya and Paraguay-Paranskaya. They are irrigated by the largest rivers in America and all are connected to each other, forming a continuous strip of plains in the middle of the continent.

The large, eastern part of the mainland is a platform. In the north and west, it is bordered by a zone of structures.

The foundation of the South American platform for the most part precambrian age, and in the south - Hercynian. On this basis, on modern tectonic maps of the South, the Guiana-Brazilian (South American) platform is distinguished on the Archean-Proterozoic folded basement and the Patagonian platform on the Hercynian base. The development of platform structures in South America apparently took place in close connection with the platforms of other continents of the southern hemisphere - Africa, Australia, Antarctica, and South Asia. The structure of the platform is characterized by the presence of protrusions of the ancient basement and depressions, in which the ancient folded base is hidden under strata of younger sedimentary deposits. Uplands in the relief usually correspond to the highlands of the eastern part of the mainland, and depressions to lowlands. However, there is no complete coincidence of structure and relief.

Precambrian orogenic cycles covered a significant part of South America. Maybe, what in the Precambrian, there was a connection between all the continents of the southern hemisphere. At the same time, vast geosynclinal basins were formed, one of which was the Andean basin. geosynclineslasting on the north of the Cordillera Geosyncline of North America.

In the Cambrian, there was a significant trough at the site of the Amazonian lowland, which then spread to the Paraguay basin. The sea occupied large areas on the platform in the Devonian, and in the Carboniferous period its area decreased again. Obviously, in the southern part of the mainland, approximately south of 37 ° S. sh., from the beginning of the Paleozoic there was a deflection of the geosynclinal type, in which mountain building occurred during the Hercynian cycle, what led to the creation of the Patagonian platform. These folded structures (Gondwanaids) are docked from the south to Precambrian platform, forming a single whole with it. The Precambrian base of the platform underwent splits during the Hercynian cycle, which in the southern part of the Brazilian salient were accompanied by powerful outpourings of magma. Manifestation Hercynian orogeny was also in within the Andean geosyncline, and mountain building captured its eastern margin adjacent to the platform.

Throughout the Paleozoic, the huge continent of the southern hemisphere, Gondwana, continued to exist as a single whole. At the end of the Carboniferous and in the Permian, in connection with the completion of the Hercynian folding and the general uplift of the land, there was continental glaciation on Gondwana. This is evidenced by the finds of the ancients moraine in the southern part of the Brazilian Highlands, as well as in Africa and Australia.

In the Triassic, a trough formed in place of the South Atlantic Ocean, and Gondwana began to disintegrate.

On the platform during the Mesozoic, the destruction of previously formed mountains and the accumulation of large masses of continental sediments took place, which gradually filled the areas of troughs, turning them into dry land.

In the Lower Cretaceous, orogeny began within the Andean geosyncline, which at first covered its western regions and was accompanied by intense volcanic processes. In the Tertiary, mountain building spread to the eastern parts of the geosynclinal area, and in the Pliocene the Coastal Cordillera were formed and the final connection between the two American continents took place. The outskirts of the platform were also captured by mountain building processes, as a result of which strongly altered sections of Precambrian and Upper Paleozoic structures were attached to the Andean system.

At the end of the Tertiary and at the beginning of the Quaternary period, the entire Andes system was covered by differentiated vertical movements, faults and volcanism.

Lowering at the end of the tertiary period caused the sinking of a significant part of the western outskirts of the Andes. The modern Andes represent only the eastern edge of the folded zone, while its main part is submerged under the waters of the Pacific Ocean. Vertical movements, which resulted in the uplift of the rest of the Andes, led to increased denudation and the formation of a number of alignment surfaces and a system of steps, which are a distinctive feature of the relief of the Andes. Volcanism and seismicity as evidence of incomplete processes mountain building, are characteristic of the Andes and at the present time. The final phases of the orogenic cycle also affected the entire platform part of South America. They manifested themselves in the formation of faults, accompanied by the outpouring of lavas, the uplift and subsidence of individual areas and the associated from this revitalization of the processes of erosion and denudation.

In the Quaternary period, the Andes underwent mountain glaciation. In some places the glaciers extended beyond the borders of the mountainous country, as evidenced by the accumulation of loess-like sediments on the neighboring plains between 30 and 40 parallels.

The following large structural and morphological regions are distinguished on the territory of South America:

Brazilian Highlands - the most extensive rise in within the platform. It extends in the eastern part of the mainland from 4 to 30 ° S. sh. Most of the highland corresponds to the protrusion on the surface of the folded base of the platform, welded from the Archean and Proterozoic folds. But in the center of the highland, the crystalline basement is deeply lowered and overlain by horizontally lying, but highly elevated deposits of the Mesozoic. Thus, the interior of the highland is a depression in the folded base of the platform.

The eastern and southeastern margins of the massif, facing directly to the Atlantic Ocean, are uplifted by faults and are strongly dissected. They break up into a series of ridges reaching over 2000 m in height. These ridges rising high above by the ocean or over a narrow coastal plain, to the center of the highlands they gradually descend, turning into a wavy peneplaned surface with an average height of 600 800 m. The southeastern edge of the highland comes close to the coast in the Rio de Janeiro region, where the highly dissected coast, accompanied by small islands, testifies to recent land subsidence. To the north and south of this area, the Brazilian Highlands recede from the ocean, separated from it by a young sandy plain with a lagoon coast.

The sedimentary interior of the highland consists of a series of steep-sloped mesas. To the northwest and to the north, the highland decreases markedly towards the adjacent low-lying plains.

The edges of the highlands in these places, and the presence of crystalline rocks celebrated numerous rapids and waterfalls with which the Amazon tributaries flowing from the Brazilian Highlands abound.

In the north of the mainland, an extensive protrusion of the folded base of the South American Platform corresponds in the relief of the Guiana Highlands.

The highest and most dissected is the central part of the highland, between the valleys of the upper Orinoco and Essequibo rivers. Separate ridges, crowned with strata of dense sandstones, reach 1000-1500 m, and the highest massif exceeds 2500 m. The eastern part of the highland is a hilly crystalline plateau with a raised southern margin.

The western part of the Guiana ledge is not orographically connected with the rest of the highlands, but is separated from it by the Orinoco lowland. This is the Pardaos massif adjacent to the Andes, within whom crystalline rocks covered strata Cretaceous and Tertiary deposits and are exposed only in the deepest valleys.

In the extreme southeast of the continent, on the Patagonian plateau, the base of the platform is formed by structures of the Hercynian age. In the northern part, they protrude to the surface, and to the south they are covered with chalk sedimentary deposits and volcanic rocks. The surface of the plateau is small dismemberedbecause of the dry climate there nearly there are no streams. The plateau, reaching 1500 m in height, approaches the very shore of the Atlantic Ocean and breaks off to it in 100-meter steps.

On either side of 30 ° S sh. there is a section of the platform that was late tertiary uplifts due to mountain building within the Andean geosynclines... At present, meridional blocky ridges are rising there, composed of crystalline rocks and reaching heights from 2000 to 6000 m. Between the ridges there are depressions filled with continental deposits. The ridges called the Pampinian Sierras and Precordillera are partly part of the Andes system.

The most extensive lowland in South America - Amazonian - one of the largest in the world, formed on the site of an ancient extensive trough within the platform. It is located between the Andes, Brazilian and Guiana highlands. The folded foundation is submerged to a depth of many thousands of meters. In the western part, the surface of the lowland is almost perfect flat... To the east, that is, downstream of the Amazon, the Guiana and Brazilian highlands converge and the alluvial lowland remains only in the form of a wide strip along the course of the Amazon. To the south and north of the valley, the crystalline basement of the platform lies close to surfaces and is exposed by the deep valleys of the tributaries of the Amazon.

In the trough between the Guiana Highlands and the Andes, there is the Orinok Lowland, filled with marine Tertiary sediments and continental sediments carried from the neighboring mountains. Its western part is lower and flat, the eastern part is elevated and dissected by deep river valleys on a plateau 200-300 m high.When the Orinoco flows into the Atlantic Ocean, a flat swampy delta plain with footprints recent sinks.

In the basin of the Parana, Paraguay and Uruguay rivers, in the zone of the platform trough between the Brazilian Highlands and the Andes, there are the Gran Chaco Plain and the La Plata Lowland.

In the northwestern part, in Gran Chaco, heights reach 600-800 m, and a dissected surface folded continental tertiary deposits. To the south, the surface drops. It is covered by strata of Quaternary alluvial, fluvioglacial and loess-like sediments, under which are hidden more ancient continental strata, reaching a great thickness. To the south of La Plata, isolated highlands rise within that part of the lowland called the Pampa. They represent the protrusions of the Precambrian and Paleozoic structures of the platform and are called the Sierras of Buenos Aires.

The north and west of the continent is occupied by the complexly constructed Andes system, diverse both in tectonic and morphological terms. In the structure of the mountain system, a number of parallel orographic zones are distinguished, replacing each other from the Pacific Ocean inland: along the coast of the Pacific Ocean and along the islands, there are low plateau-like ridges of the Coastal Cordilleras. At the greater parts the coasts of the mountain drop abruptly to the ocean, forming an undivided longitudinal tectonic coast.

The coastal Cordillera do not form a continuous strip. They appear at the extreme northern section of the coast as a continuation of the mountains of Central America, then break off and continue again only to 20 ° S. sh. In the far south in connection from recent subsidences have fragmented the outskirts of the Andes and have become islands in close proximity to the mainland.

The main part of the mountain system consists of structures of the Mesozoic-Tertiary age. An important role in the structure of mountains is played by volcanic rocks, extinct and active volcanoes. The most important areas of modern and recent volcanism are in the Andes on both sides of the equator in Ecuador, south of 30 ° S. sh. within Chile and in the central part of the mainland between 13 and 29 ° S. sh.

The ridges of the Andes, called the Cordilleras, run in parallel chains or fan out. In the middle part of the mountain system, between the Cordilleras, there are vast plains cluttered with debris and volcanic eruption products. They're called Andean plateaus or Punami. Their heights are 3500-4500 m, while in the Cordillera individual peaks rise to 6000 and even 7000 m. The High Cordilleras of the Andes are distinguished by a typical alpine relief, with mountain-glacial forms and modern glaciers.

In the southeast of the mainland at the parallel of 40 ° S. w... The Andes are joined in the form of blocky ridges by the Hercynian structures of the Natagon platform, the so-called "Patagonids", reworked by Mesozoic uplifts.

The mineral resources of South America are very unevenly explored. But what is already known testifies to the enormous wealth of the mainland in a variety of minerals. There are especially large deposits of various metal ores associated as with the most ancient crystalline rocks of the platform basement, and with the processes of volcanism that took place in the Andean geosynclinal area. But there are also large reserves of minerals on the mainland. sedimentary origin.

The richest reserves of metal ores are concentrated in the Andes, mainly in their central part. These ore deposits were formed during the formation of the Andes in connections with the processes of volcanism and contact metamorphism. Bolivia has deposits of tin, tungsten, antimony, lead, zinc and silver. In Peru, polymetallic ores containing copper, lead, zinc and gold are widespread in the territory Colombia - reserves of gold and platinum. Chile is rich in copper, there is one of the largest copper deposits in the world, formed in connection with the processes of Tertiary volcanism. In addition, on average Chile there are large deposits of radioactive elements. With processes volcanism in the Andes connected sulfur deposits.

In the Brazilian and Guiana Highlands, there are deposits of iron ores in the Algonquan shale and conglomerates (the largest of them are in the southeast of the Brazilian Highlands and on the northern slope of the Guiana Highlands). Manganese ores formed as a result of weathering of ancient crystalline rocks occur in approximately the same areas.

Numerous gold deposits are associated with ancient intrusions and metamorphic processes, which are found in the southeastern edge of the Brazilian Highlands and in the northeast of the Guiana Highlands. The products of destruction of ancient pegmatite veins contain radioactive elements and diamonds.

In the Guiana, and partly in the Brazilian highlands, there are large deposits of bauxite formed as a result of lateritic weathering of acidic and alkaline rocks of the ancient crystalline base.

The whole area between the Andes and the Brazilian Highlands, intermontane basins and the coastal zone of the Andes are rich in oil. Special big its reserves are concentrated in Venezuela around the Maracaibo lagoon and in the Caribbean Andes, as well as in Colombia, in the valley of the Magdalena and Cauca rivers. Relatively recently, oil was found within the platform - in Patagonia, the Amazonian lowlands and the Brazilian highlands.

On the Pacific coast ocean, the Atacame Desert and the coastal islands are home to the world's only deposits of natural nitrate. It is a product of the decomposition of organic residues accumulated in dry and hot climates in previous geological periods.

The process of the formation of valuable organic substances (guano), used as fertilizer, is still taking place on the coastal islands of the Pacific Ocean. The material for this is organic debris accumulated by birds nesting there.

Features of the geological structure of South America

There was an ancient supercontinent 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 distinction between the eastern and central parts of 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 of the outcropping of the ancient crystalline basement of the platform to the surface - Guiana and Brazilian shields ... The western part of the mainland is represented folded area formed by the collision of the continental plate and the oceanic lithospheric plate.

The oceanic plate bends and goes under the continental plate, 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 area is young - cenozoic folding ... This is evidenced by volcanic eruptions and frequent earthquakes. An active process of mountain building is underway. The West Coast of South America is part of "Pacific Ring of Fire" - Areas of active seismic activity.

In the past, the platform part of the continent has experienced repeated submersions and uplifts. This is evidenced by the deposits of sedimentary rocks, including - marine deposits.

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

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 the language of the Indians, this means "Copper mountains" .

The Andes Mountains stretch along the Pacific coast in three parallel mountain ranges. Many peaks rise above $ 6,000 m above sea level.

Highest point of South America - city \u200b\u200bof Aconcagua ($ 6960 m).

At the same time, it is the highest point of the entire western hemisphere.

There are also many active volcanoes. 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. 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 a plain with absolute heights - more than $ 500 m.

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

Remark 1

Amazonian lowland - the largest lowland in the world.

Thanks to marine sediments, the northern parts of the plains are rich in oil. On crystal shields formed Brazilian and Guiana Highlands ... As a result of ancient tectonic activity, the subsidence and uplift of the platform were accompanied by faults in the earth's crust, lava outcrops. In some places the relief of the plateaus looks like mesas. They are replaced by landscapes of hilly plains, low massifs, indented by gorges.

Minerals

The distribution of minerals is also associated with the geological structure.

There are deposits on ancient shields iron, manganese, uranium ores, bauxite, diamonds.
The Andes, living up to their name, are famous copper ores,deposits gold.
Large deposits discovered in the north of the mainland oil.
On the deserted west coast, due to the peculiarities of the climate, deposits were formed sodium nitrate.

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

Features of the geological structure of South America

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

In the past, the platform part of the continent has experienced repeated submersions and uplifts. This is evidenced by the deposits of sedimentary rocks, including - marine deposits.

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

Features of the relief of South America

The Andes Mountains stretch along the Pacific coast in three parallel mountain ranges. Many peaks rise above $ 6,000 m above sea level.

Highest point of South America - city \u200b\u200bof Aconcagua ($ 6960 m).

At the same time, it is the highest point of the entire western hemisphere.

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 a plain with absolute heights - more than $ 500 m.

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

Remark 1

Amazonian lowland - the largest lowland in the world.

Minerals

The distribution of minerals is also associated with the geological structure.

There are deposits on ancient shields iron, manganese, uranium ores, bauxite, diamonds.
The Andes, living up to their name, are famous copper ores,deposits gold.
Large deposits discovered in the north of the mainland oil.
On the deserted west coast, due to the peculiarities of the climate, deposits were formed sodium nitrate.

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

The relief of South America is diverse and contrasting. By the nature of the structure of the surface on the mainland, two parts are distinguished. Most of the eastern part is dominated by low-lying, elevated plains and plateaus, in the west - the longest mountain ranges of the Andes.

Low-lying plains (Amazonian, Orinokskaya, La Platskaya) have a flat relief and are composed of marine and lacustrine-river sediments. The relief of the western part of the continent is the result of the interaction of several lithospheric plates, on the border of which mountain-building movements occur.

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

South America is rich in mineral deposits. The richest deposits of iron, manganese, nickel ores, uranium, bauxite deposits containing aluminum are confined to the ancient shields of the platform. Oil, natural gas and coal were found in the depressions and depressions of the platform. A deposit of non-ferrous and rare metals was 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 ores of molybdenum, silver, tungsten, lead and zinc. Sulfur, boron, iodine, and saltpeter are mined from nonmetallic minerals on the Pacific coast and in the foothills of the Andes. There is oil in the intermontane basins.

South America is made up of two main geological elements: the Andes - a fold 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 on the subsided areas, and crystalline rocks on the raised areas. Due to the different rates of uplift, cracking of the earth's crust occurred, and lava was splashing to the surface.

The mainland, due to the peculiarities of the internal structure, can be conditionally 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 of the mainland.

2. Plateau. In the east Guiana and the Brazilian Highlands are formed by foundation outcrops. 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 view 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 range stretches along the Pacific coast, with average heights ranging from 3000 to 5000 m. The highest point is Mount Aconcagua (6960 m). These are young mountains, strong earthquakes and volcanisms occur here and now, as a result of which the volcanoes of San Pedro and Cotopaxi.

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

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

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, 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 GEGRAPHIC POSITION.

The mainland area is 17.8 million square kilometers without islands and 18.3 million square kilometers with islands. Extension from north to south at -70 degrees. h.d. exceeds 7500 km, from west to east (in the widest part) more than 45 oo km. South America in the northern part is crossed by the equator. The northernmost point is Cape Galinhas, 13 degrees. s.sh .; the extreme southern mainland point is Cape Froward, 54 gr. S, island Cape Horn, 56 gr. south latitude The mainland lies entirely in the western hemisphere. The westernmost point is Cape Parinyas, 81 degrees. w.d .; the easternmost point of the Cape Cabo Branco, 34 gr. h.d.

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

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

Geological structure and main landforms of South America

Washed in the west by the Pacific Ocean, in the south by Drake's irrigation, in the east by the Atlantic Ocean, in the north by the Caribbean Sea of \u200b\u200bthe Atlantic Ocean basin. In the north there is a warm North Passat 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 Western Winds current, in the west - the cold Peruvian Current, in the north in the west - warm El Niño current. The coastline is weakly indented. Small bays are located at river mouths (La Plata, Maracaibo). Adjacent islands: in the north - the Lesser Antilles, in the southeast - the Falkland Islands (Malvinas), in the south - Tierra del Fuego, in the southwest - the Chilean archipelago. The geographic 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 FOSSILS.

The relief of South America is asymmetrical. Most of the mainland is occupied by vast plains of different heights. In the west is one of the highest mountain systems in the world - the South American Cordillera (Andes). The average height of the mainland is 580 m, the highest point is Mount Aconcagua 6960 m, the lowest is the Valdes Peninsula -40 m. The features of the relief 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 highlands. Powerful block processes took place within the Guiana Plateau, therefore the plateau has a highly dissected relief. The highest point is Mount Roraima 2771 m, average heights from 500 to 1000 m.

The Brazilian plateau corresponds to three shields: South Amazonian, East Brazilian, West Brazilian. This plateau rises gently from the north and northwest to the southeast. The highest point is Mount Bandeira 2890 m. Active magmatism took place within this territory, traps and volcanic plateaus are found here. This territory is over

its formation. Here peneplains (leveling surfaces, denudation plains) are formed.

Between the shields there are syneclises (deflections) of the platform basement, which are filled with thick strata of sedimentary rocks. They correspond to the vast low-lying plains of South America: Amazonian, La Platskaya, Orinokskaya.

In the west, the platform is adjoined by an area of \u200b\u200balpine folding, which was formed in the Cenozoic as a result of the subduction of the Nazca plate and the South American lithospheric plate. This folding area corresponds to the Andes, which are among the highest and highest mountains. The highest point is Mount Aconcagua 6960 m. The mountain building processes have not yet ended here and are accompanied by earthquakes and volcanism (volcanoes Cotopaxi, Chimborazo). Tectonic processes are strong in the Caribbean, North and South Andes, calm in the Central and Patagonian Andes. The Andes are composed of parallel ridges. Approaching, they form mountain nodes, and where the ridges diverge, lie the Central Andean highlands and plateaus 3500-4000 m high.

South America has an enormous mineral resource base. Ore ones are confined to the outcrops of the crystalline basement to the surface and to the Andean fold belt. Nonmetallic - to the cover of sedimentary rocks of the platform. In ancient igneous and metamorphic rocks and weathering crusts, significant deposits of iron (Minas Geiras - Brazil), manganese, bauxite, titanium and uranium ores were formed. There are concentrated reserves of beryllium, niobium, zirconium, tantalum. 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, in the territory of Peru and Chile in the Andean belt, large reserves of copper are concentrated, in Bolivia - a tin belt. Emeralds are mined in Colombia. In the sedimentary cover of the Orinok, Amazon and La Plata lowlands - oil deposits, especially in Venezuela. Atacama contains 99% of the world's saltpeter reserves.

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

In general, the climate of South America is more diverse than that of Africa and Australia. Average annual temperatures in most of the mainland are from +20 to +28, and only in the south are these indicators 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 impact on the climate of South America, from which the cold pampero wind bursts into the temperate and even subtropical zone. In Patagonia, the temperature can drop to 0 in summer and -30 in winter; in the subtropics in the south of the Brazilian Highlands 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 - an average of 1700 mm. The drainage layer into the hydrographic network is 700 mm. These values \u200b\u200bare twice the average on Earth. 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 - inland areas of the tropical belt, the south of the La Plata lowland, the zone of barrier rain shadow - in Patagonia. In general, the climate of South America, which is characterized by an abundance of warmth and light in most of the territory, creates favorable conditions for year-round vegetation of plants.

INLAND WATERS.

Since South America is the wettest continent on Earth, it has formed one of the largest hydrographic networks in the world. South America occupies 12% of the land area, but it accounts for 36% of the world's runoff into the ocean, of which 15% belongs to the Amazon. The pattern of the hydrographic network is extremely asymmetric, which is determined by the features of the relief. The main watershed runs along the peaks of the Andes near the Pacific Ocean, so all 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 rainfall, are full-flowing throughout the year with two peaks in spring and autumn during zenital rains. Rivers of the subequatorial type are also fed by rain. These are large tributaries of the Amazon, the Orinoco River and Paraguay. They have a maximum discharge in late summer, early autumn and winter low water. The rivers of the tropical zone in the inland regions are shallow, and in the southeast of the Brazilian Highlands, they are deep throughout the year. Most of the rivers in the upper reaches are mountainous, 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), there is the world's longest Iguazu Falls (about 3000 m long, includes more than 270 cascades).

There are few large lakes. In the southern part of the Andes - glacial lakes, in the north - the lake-lagoon Maracaibo of tectonic origin, in the Central Andes at an altitude of 3800 m there is 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 ZONES.

Due to the large extent from north to south, natural zoning is clearly presented on the mainland from equatorial forests in the center to semi-deserts and deserts of the temperate zone in the south. Due to the prevalence of a hot, humid climate on the mainland, forests are widespread here and relatively few deserts and semi-deserts.

1) The zone of humid 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. Due to the processes of chemical weathering, fertile red-yellow ferralite soils are formed in the selva. Various types of palm trees, cocoa, hevea, many orchids, lianas, melon trees, ceiba grow here. Many animals are adapted to life in trees: chain-tailed monkeys, sloths, wood porcupines; also tapirs, anteaters, jaguars live here;

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

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

3) The savannah zone occupies the Orinoco lowlands and most of the Guiana and Brazilian plateaus. Located in the subequatorial climatic zone. Here red ferralite and red-brown soils are formed. Savannahs of the northern and southern hemispheres within the southern

The Americas differ. In the northern savannas (llanos), palm trees and acacias, mimosas, milkweed, and a bottle tree grow among the herbs. In the southern savannas (campos), the vegetation is poorer due to less rainfall: there are low-growth kebracho forests with very hard

wood. Among the animals in the savannas live small deer, wild pigs-bakers, armadillos, anteaters, jaguars, cougars, ostriches-rhea.

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. On stony, barren soils, cacti and thorny cushion shrubs grow here and there. Onshore

the rocks are bird colonies.

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

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

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

7) Altitude zonation.

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

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

Up to 4000 m - low trees and shrubs, light forests appear. There are heather and myrtle thickets, undersized bamboos.

Over 4000 m - alpine meadows (paramos). The vegetation consists of rare cereals and cushion-like shrubs. Moss swamps are located on flat areas, and rocky barren deserts are characteristic of large slopes.

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

In the subtropics at the foot of the deserts are located, turning into a belt of hard-leaved forests, extending up to an altitude of 2000 m on the western slopes and up to 1800 m on the eastern. Here you can find plane trees, glanders, and in the undergrowth there are blooming geraniums. Stiff-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 relief is plain. In the west, there is an area of \u200b\u200bnew folding, where the relief is mountainous. The central and eastern parts are occupied by plains (lowlands, hills and plateaus), and in the west by the Andes mountains.

The Andes are the longest (9000 km) and one of the highest (Mount Aconcagua, 6962 m) mountain systems of the 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 height is about 4000 m.

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

Low-lying plains (Amazonian, Orinokskaya, La Platskaya) have a flat relief and are composed of marine and lacustrine-river sediments.

Features of relief forms of South America

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

Physical and geographical characteristics of the Inner Plains of South America.

The inner plains are located between the Brazilian Plateau and the Andes in the central part of the mainland and are confined to three belts - subequatorial, tropical and subtropical. The Inner Plains include five natural areas: Mamore, Pantanal, Gran Chaco, between the Parana and Uruguay rivers, Pampa.

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

H variability Pantanal , dry in winter and flooded with rain in summer. It is composed of a thick layer of sedimentary rocks. The Pantanal plains are dominated by tall grasses, in some places trees and bushes. Hygrophilous forests grow along the rivers.

Plains of Gran Chaco. This is the hottest place in South America, the average January temperature is + 28, + 29 ° С, the absolute maximum is + 47 ° С.In the region, the change of winter dry and summer rainy seasons is well expressed. Precipitation is predominantly stormy. In the western, more elevated part of the region, there are forests of thorny acacias, cacti, agaves; to the east, areas of steppes and forests appear. In more humid places, a wax palm grows. In the north of the region there are vast swampy areas.

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

The southern part of the Inner Plains is Pampa - grassy plains. The climate of Pampa is subtropical. The average temperature in January is + 22 - + 24 ° С, in July + 7 - + 9 ° С; precipitation falls 1000-1200 mm per year, they are distributed evenly over the seasons.

In the flora of Pampa, there are up to a thousand species of various cereals. There are areas devoid of grass. On the clay soils of Pam-py, the grass is silvery hyneria. The fauna of Pampa is not rich and monotonous. Viscachi is often found - a large rodent. Predators (puma) are rare. Of the birds, the ibis, ipikakha, tinamu are characteristic, in size and appearance resembling a partridge.

44. Precordillera and Pampinian Sierras (physical and geographical characteristics).

Precordillera - there are large contrasts of 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 rocks of the Precambrian and Paleo-Zoic, have been subjected to prolonged destruction and leveling. Wide valleys - bolsons and depressions (Salinas Grande) were formed between the mountain ranges.

The Predkordillera is characterized by a continental dry climate. Precipitation falls unevenly. The amount of precipitation decreases from east to west, and the eastern slopes of the mountain ranges receive more precipitation than the western ones. The river network is poorly developed. Salt marshes occupy a large area.

The vegetation has a xerophytic appearance; the monte-type shrub formation is widespread. At an altitude of 500-1000 m, the remains of subtropical forests with hard-leaf evergreen trees and shrubs have been preserved. Above 2500 m, the mountain grass steppe begins.

To the south, forests become less frequent. In the southwest, large areas are occupied by semi-deserts with gray soils and saline soils.

The southeastern part of Predkordil-er occupies 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. The position of Patagonia in temperate latitudes in the zone of western transfer, between two oceans, was supposed to determine a mild climate and a good development of the hydraulic network. The main reason for the aridity of Patagonia is that the westerly winds prevailing in these latitudes carry the humid sea air of the Pacific Ocean and run into the mountain barrier of the Andes. The annual amount of precipitation in Patagonia is 120 - 200 mm. The vegetation cover is dominated by pillow-like and creeping forms of shrubs with pronounced xeromorphism; there are few trees. Among the cereals are abundant prickly, nondescript bushes of charilya, dense cushions of bolax and azorella; there are southern species of cacti.

Among the endemic representatives of the fauna of Patagonia, it should be noted the skun-sa sorillo, the fox-like Magellan dog, the Darwin ostrich (southern species of rhea). Rodents are also characteristic (mara, tuko-tuko, etc.), there are also Pampas cat, armadillos.

46. \u200b\u200bNorthern Andes (physical and geographical characteristics).

The mountain ranges of the Northern Andes, divided by river valleys, extend from the shores of the Caribbean Sea to 5 ° S. sh. The North Andes include the Caribbean Andes located along the coast of the Caribbean Sea, the Northwest Andes (Andes of Colombia and Venezuela) and the Andes of Ecuador.

Caribbean Andesin contrast to other parts of the mountain system, they are wide-spread. These are the northernmost and youngest ridges, they are more arid than the nearby plains. The mountains are almost devoid of forest cover. The main folds 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 sparse forests or thorny shrubs (chaparro) developing on red-brown soils. Above, with a decrease in temperatures, precipitation becomes more, therefore, forests are denser, and evergreens appear at an altitude of 1500-1600 m.

To the north of the Caribbean Andes are located Caribbean lowlands,folded with alluvium. Lake Maracaibo once occupied the entire lowland, now its area is shrinking due to the filling of alluvial nano-sama. At the same time, the coastal areas are experiencing a gradual subsidence.

The second tectonic trough is occupied by the lowlands of the Magdalena and Kauki rivers, composed of alluvium and coarse-detrital material carried from the mountain ranges of the Andes Northwest Andes- the most ramified and complexly constructed part of the Andean mountain system. They are located mainly in Colombia. Three main ridges are well pronounced here - the Western, Central and Eastern Kor-Dilyera 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 (Huila volcano, 5750 m, Ruiz peak, 5400 m). The Western and Eastern Cordillera below; the latter is divided in the north into two ridges (Sierra de Merida and Sierra de Perija), covering the Ma rakaibo lowland. Between the Eastern and Central Cordillera is the valley of the Magdalena-Graben River, filled with a thick stratum of Cretaceous and Cenozoic deposits. In the northwest, along the Pacific coast, the low Sierra de Baudo stretches, composed of Cretaceous and Tertiary tuffaceous strata.

The Northwest Andes are located in subequatorial and equatorial climates. 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 largest amount in South America). The interior areas are less humid, but aridity is not expressed. Climatic features are reflected in the zoning of the soil and vegetation cover. In the west, on the Pacific coast and the slopes of the Sierra de Baudo, a dense mountain gilea is formed. To the east, the amount of precipitation decreases, so the lower parts of the slopes are covered with summer-green light forests and shrubs, higher - with mixed deciduous-evergreen forests, and only at an altitude of 1000 m does the wet mountain gilea begin. Here one 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 also a sunbird are characteristic.

Above, as the temperature decreases, belts of woodlands and crooked forests appear, at an altitude of 2500-3500 m mountain meadows of paramos stretch.

Geological structure, relief, minerals of South America

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

Andes of Ecuador(from 2 ° N to 5 ° S) - the narrowest part of the Andes, high-mountainous and tectonically active. Two parallel chains are well pronounced in them - the Eastern Cordillera and the Western Cordillera, separated by a series of intermontane basins. The total width of the mountain system is about 90 km. The ridges consist of separate mountain ranges, separated by saddles, poorly expressed in the relief. The main peaks are, as a rule, active and extinct volcanoes, including the highest volcano Chimborazo (6267 m). Active volcanoes Cotopaxi, Antisana, Sangay are known. Intermontane basins are located at an altitude of 2500-2800 m, they are filled with a layer of volcanic ash, tuffs and alluvium. The epicenters of earthquakes are most often in the area of \u200b\u200bthe intermontane valley separating these Cordillera chains.

To the west of the Andes mountain range, there is a strip of the coastal plain of the Costa, with a hot and humid climate. 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. Savannahs with areas of humid equatorial forests, occupying the northern part of the Costa, are gradually replaced to the south by dry steppe vegetation. In the mountainous part, the vertical zonation is well expressed. Up to 800-1000 m, the change in climate and vegetation cover is felt even weakly, then the amount of precipitation increases noticeably, the amplitude of temperatures decreases with their general decrease. Cinchona, balsa, ceiba appear in this belt. Palm trees disappear from a height of 1500-1800 m, and there are more tree ferns. Above 3000 m vegetation of the paramos type prevails on mountain-meadow and mountain-steppe soils. Eternal snows begin from an altitude of 4200-4500 m. The mountain climate is more favorable for human life than the climate of the Costa and Giley.

Relief... In the relief of South America, the flat-plateau platform out-of-Andean East and the mountainous Andean West are clearly distinguished, 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 Llanos Orinoco, Amazonian, 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.

The Guiana Plateau rises towards the center (Neblina, 3014 m), the Brazilian Plateau from the northwest. in the south-east (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 (height up to 1500-1700 m), within which there are outlier cone-shaped peaks and ridges (for example, Serra do Espinhas) or table, mainly sandstone, uplands - the so-called shapads (Auyan-Tepui and Roraima, etc.). The eastern edge of the Brazilian Highlands is divided into separate massifs (Serra da Manticheira, etc.), which have characteristic forms of "sugar heads" (for example, Pan di Asucar in Rio de Janeiro). The troughs and depressions of the Brazilian Plateau in the relief are expressed by monoclinal-bedded plains with raised edges-cuestas, accumulative plains (depression of the São Francisco River, etc.) or lava plateau (in the middle reaches of the Parana). The relief of Patagonia is dominated by layered, including volcanic, stepped plateaus, covered by ancient moraine and water-glacial deposits; the plateaus are cut by deep canyons of rivers originating in the Andes; arid forms of denudation are characteristic.

The Andes range system stretches for 9,000 km in the north and west of the mainland. In the northeast 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 Cordilleras (Cordillera de los Andes), reaching 6960 m (Aconcagua), rises in the west of Yu.A. and is subdivided into the North, Central and South Andes. The Northern Andes (up to 5 ° S lat.) Are distinguished by the alternation of high folded-block ridges and deep depressions. In the Ecuador they consist of the Eastern and Western Cordilleras, the depression between which is filled with the products of the activity of the volcanoes Chimborazo, Cotopaxi, etc. In Colombia, there are three main Cordilleras (Eastern, Central and Western), separated by the depressions of the river. Magdalena and Cauca. Volcanoes (Huila, Ruiz, Purase, etc.) are concentrated mainly in the Central and in the south of the Western Cordillera; for the central part of the Eastern Cordillera typical ancient lake plateaus, height 2-3 thousand meters. 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 lat.) Are much wider and more monolithic than the North. They are characterized by internal plateaus raised to 3.8-4.8 thousand m, bordered by marginal ridges; the highest mountains have significant glaciation. The southern part - the Central Andean Highlands - the widest (up to 750 km) stretch of the Andes; its main element is the Pune plateau with the ancient lake plateau Altiplano in the southwest and a number of blocky ridges in the east and south. In the east, Pune is framed by the Cordillera Real; in the west, by the volcanic Western Cordillera (2nd volcanic region of the Andes with the volcanoes Misty, Llullaillaco, Sahama, and others), a longitudinal tectonic depression (with the Atacama Desert), and the Coastal Cordillera.

In the Southern Andes in the north (up to 41 ° 30 "S), the relief is expressed: the double Main Cordillera (the city of Aconcagua in the eastern, or Peredovoi), to which the Precordillera massifs are joined from the east; Chile's Longitudinal Valley and the Coastal Cordillera. Between 33-52 ° S latitude lies 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 - into the system of straits, and the flooded troughs of the sharply declining Patagonian Cordillera - into the fjords.Glacial forms dominate.Modern glaciation in YA occupies an area of \u200b\u200b25 thousand km 2, of which more than 21 thousand km 2 falls on the Southern Andes. There are also glaciers in the Western Cordillera, between 9 and 11 ° S latitude and on the islands of Tierra del Fuego.