Relief South America diverse. Based on the nature of the geological structure and the features of the modern relief, South America is divided into two heterogeneous parts. East End continent is the ancient South American platform; western - the actively developing folded belt of the Andes. The raised sections of the platform - the shields - correspond in relief to the Brazilian and Guiana plateaus. The troughs of the South American platform correspond to gigantic lowland plains - the Amazonian, Orinoco, a system of internal plains (Gran Chaco plain, 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 sediment brought by the current. In the west, the lowland is very flat, the river valleys are weakly incised, the heights barely reach 150 m. Its northern and southern outskirts, underlain by crystalline shield rocks, are elevated and gradually turn into plateaus.
The Brazilian plateau is located in the east of the mainland. It represents protrusions of the crystalline foundation 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 altitudes from 250-300 m in the north to 800-900 m in the southeast. The relief of the plateau is a relatively level surface, above which blocky massifs and plateaus rise.
In the north of the continent, the Guiana Plateau (300-400 m) is confined to the vast protrusion of the folded base of the platform. Its relief is dominated by stepped plateaus.
The vast plains and large areas of the plateaus of South America are convenient for the life and economic activities of the population. (Show on map largest lowlands and plateaus and determine their maximum heights.)
The Andes are the longest mountain range on land, measuring 9,000 km. The Andes are one of the highest mountain systems globe. 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 m. The highest of them is the city of Aconcagua (6960 m).
The formation of the Andes is the result of the interaction of two lithospheric plates, when oceanic plate Nazca "drew" under the continental South American. At the same time, the edge of the continental plate folded 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 we can note such as Chimborazo (6267 m), Cotopaxi (5897 m). West Coast occupied by the Andes belongs to the Pacific “Ring of Fire”.
The strongest in the world recorded at 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 ranges lie internal plateaus and plateaus, ranging in height from 3500 to 4500 m.
Minerals of South America
The continent is rich in minerals. The richest deposits of iron and manganese ores are confined to the ancient shields of the South American Platform: the center and outskirts of the Brazilian Plateau, as well as the north of the Guiana Plateau. The largest iron ore mining area is Carazhas. In the northern part, on the outskirts of both plateaus, there are very large deposits of bauxite, a raw material for the aluminum industry. Bauxite occurs at shallow depths and is mined open method.
In the Andes, ores of copper (Peru, Chile), tin (Bolivia), lead and zinc (Peru) have been explored. 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. This primarily applies to emerald mining in Colombia. From noble metals In South America, the largest reserves of silver are in Peru. The Andes belt is also famous for some non-metallic minerals. Among them, saltpeter takes first place. The famous Chilean saltpeter and iodine are mined in the dried-up reservoirs of the Atacama.
The relief of South America is more diverse compared to Africa and Australia. High Andes in the west they separate the main flat part of the continent from the Pacific Ocean. South America is characterized by active seismicity. South America is called the "storehouse of the world." The mainland is rich natural resources necessary for the development of many sectors of the economy.
The relief of Australia is unique. 95% of the continent has an altitude of no more than 600 meters above sea level. These are mostly plains. Mountains occupy only 5% of the entire continent.
Forms and main indicators of heights
The relief of Australia has remained virtually unchanged since Precambrian times; tectonic movements did not have.
Australia, like Africa, was once part of big continent Gondwana. The separation of Austria from Gondwana occurred in the Mesozoic.
The relief of the continent was greatly influenced by a process such as denduation - this is the process of transfer, demolition (under the influence of natural forces) of the products of crushing rocks into low-lying areas. It was during this process that the peneplain appeared - spacious plains with low island mountains.
Fig 1. Relief map of Australia
The basis for the relatively flat relief was the Precambrian Australian platform, which, in turn, is part of the Indo-Australian lithospheric plate, and the relatively young Epihercynian platform. Some experts note that the basis for the flat relief of the continent is also the Hindustan Platform (it is also part of the Indo-Australian lithosphene plate).
A table can be used to briefly describe all forms of Australian relief, indicating heights.
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|
Region |
Relief |
Average altitudes (above sea level) |
Maximum/minimum altitudes (above sea level) |
|
Western Australia |
Western Australian Tablelands |
400 - 500 meters |
Mount Woodroffe (Musgrave Range) -1440 meters; Mount Zil (McDonnell Range - 1510 meters |
|
Central Australia |
Central Lowlands (Lake Eyre region) |
100 meters |
12 meters (in the Lake Eyre area) |
|
Eastern Australia |
Plains (deserts and semi-deserts of Victoria, Great Sandy and Great Artesian Basin), foothills and mountains (Australian Alps and Great Dividing Range) |
300 -600 meters |
Mount Kosciuszko (Australian Alps) - 2230 meters. This is the most high point the entire continent. |
Fig 2. Mount Kosciuszko in Australia
Not in Australia active volcanoes and manifestations of modern glaciation. In some places the cones of the most ancient extinct volcanoes, but no tectonic activity is observed, although, most likely, in the past this continent was one of the centers of tectonic activity on the planet.
Landforms and minerals of Australia
The relief of the continent and, especially, its peculiar formation, influenced the amount of minerals found here. The Australian mainland is very rich in minerals and is one of the largest raw materials “pools” on the planet.
The regional link of certain resources is clearly visible on the map of Australia's mineral resources. In a condensed form, this can be presented as a table from which you can understand which Australian mineral resources are concentrated in a particular region of the mainland:
|
Region of Australia |
Minerals |
|
Western Australia |
gold (it should be noted that there are gold deposits throughout the continent, but compared to the western ones they are much poorer); polymetallic ores; uranium ores; bauxite (deposits on the Arnhem Land and Cape York peninsulas, and near the Darling Ridge; iron (large iron deposits are also found in South Australia; the largest ore deposit, Iron Knob, is located here); |
|
Central Australia |
polymetallic ores; manganese; Opal deposits are being actively mined in the Lake Eyre area. |
|
Eastern Australia |
coal deposits (brown and hard coal; Australia contains more than 9% of the world's total coal reserves); |
Fig 3. Map of Australia's mineral resources
Many deposits in Australia lie at shallow depths, which is why they are mined using open-pit mining.
Australia currently ranks:
- 1st place in iron ore mining;
- 1st place in the extraction of bauxite, lead and zinc;
- 2nd place in uranium production;
- 6th place in coal production.
It should be noted that Australia currently ranks first in the world in diamond mining. The country's largest deposit is located in the Lake Argyle region.
Among other things, Australia leads active work for the development of clay, sand and limestone deposits.
What have we learned?
The characteristics of the relief of Australia are simple. There are practically no high mountains on this continent; in area this continent is more like a large island, coastline Quite flat, a large area of the continent is occupied by plains and plateaus. But despite this, Australia is the world leader in raw materials.
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The Australian continent is extremely rich in a variety of mineral resources. The security of this southern continent different types industrial raw materials brings it to a leading position in the world in the production of the most important for development industrial production mineral resources.
Relationship between minerals and geology
At the base of the continent lies a Precambrian rigid tectonic structure - the Indo-Australian platform. It was once part of Gondwana, a supercontinent Southern Hemisphere. Periodically, in different geological periods, the platform experienced rejuvenation, was uplifted, was subject to volcanic processes, and was broken through by deep intrusions. It is with volcanism, intrusive activity and the antiquity of rocks on the mainland that the presence of the richest deposits of igneous minerals is associated.
Raised in different geological time parts of the platform began to actively collapse under the influence of temperature differences, heavy rains and strong winds. By collapsing, strong igneous rocks formed thick layers of sedimentary rocks. Over time, the clastic material experienced metamorphosis and formed special class rocks – metamorphosed rocks. Therefore, all types of rocks are represented on the continent, and geologists attribute the good supply of the Australian continent with a variety of mineral raw materials to this.
Metal ores
The Australian continent has the richest ore reserves; the country leads the world in deposits and production of high-quality lead, iron, zinc ores and aluminum-containing bauxite. The most famous Australian deposits of high-quality iron ore, Mount Goldsworth and, far beyond the borders of the country, the rated Mount Newman, are located in the north-western Hamersley Range, composed of ancient crystalline rocks.
Deposits in the Fortescue River basin with reserves of up to 20 billion tons of high-quality hematites have been discovered and exploited since 1964. The content of useful iron in the hematites of the Hamersley Range is up to 60%. Deposits with high-quality goethite ores with a useful iron content of up to 55% have also been discovered and exploited here. Annually, the production of iron ore from the Hamersley Range amounts to 80 million tons.
High-quality hematite-goethite iron-containing ores were discovered in the South in folded crystalline rocks on the low Mildback Ridge. The oldest deposits in the Mildback Range are the Iron Knob deposits. The deposits of the north-west are also famous here, namely Mount Goldsworthy, Sunrise, Shay Gap near the Pilbara.
At the famous Yampi Sound field north of the city Derby, on the small island of Cockatoo, hematites of sedimentary origin are mined. In Queensland, hematite-siderite ores of sedimentary origin are mined at the Roper Bar and Constance Range deposits. Magnetite amphibole ores are being mined at the Savage River deposits in Tasmania.
The country has a leading position in the world rankings in the exploration and production of high-quality manganese ores. The largest of these deposits is Groot Island, which is located on an island of the same name in the large Gulf of Carpentaria. Here, ores of sedimentary origin are discovered and exploited among sandy and multi-colored clay deposits of chalk. Associated with the upper Proterozoic sediments is a manganese deposit called Ripon Hill.
The continent's subsoil is rich in bauxite; the country is second in the world in bauxite mining. Bauxite layers up to 10 m thick of lateritic origin lie close to the surface and are mined by open-pit mining. Up to 80% of all Australian bauxite is mined in four ore deposits in the north - Mitchell, Bougainville, Gov and Weipa. Near the city of Perth is located large area for bauxite mining - Darling.
The continent's interior is rich in copper ores. Content useful metal in them is 2.5%. Up to 80% of Australian copper ore reserves are mined in Queensland (Mount Isa). The Kadiya, Kobar and Mount Lyell deposits produce copper-rich ores in the form of copper pyrite. In the Tennant Creek and Golden Grove deposits, copper occurs in vein form. Porphyry copper ores are mined at Mount Morgan.
The country occupies one of the leading places in geological reserves and nickel production. The western vast region of ancient volcanism and intrusive activity includes nickel sulfide ores. The richest deposits of Mount Windarra, Agnew and Kambalda have fairly high concentrations of useful nickel, up to 4.8%. In the Greenvale deposits with total reserves up to 44 million tons of silicates containing nickel are formed on ancient weathering crust. The main deposits of cobalt and rare metals platinum group.
The country is rich in polymetals, with up to 13-15% of the world's reserves. Mount Isa and Broken Hill, the largest in lead and zinc, are confined to the oldest Precambrian deposits. Large deposits of ores containing lead and zinc in the McArthur River with reserves of up to 190 million tons. It is confined here to the Precambrian cover of the platform. The deposits of Elur in South Wales and Red Rosebery in Tasmania are also known in the world.
Up to 30% of Australian tungsten deposits are concentrated in the King Island seams in Tasmania. The base metals of the westernmost of the manifestations, Mount Mulgain, contain large quantities of copper, precious gold and silver. Large reserves of rare vanadium are contained in the most ancient ores of the Yilgarn tectonic shield; here they are associated primarily with numerous gabbro intrusions.
Deposits of local tin ores are very significant, up to 80% of reserves are located in Tasmania, Mount Cleveland deposits with reserves of up to 1.7 million tons, Renison-Bell with reserves of up to 12 million tons. The content of useful tin in them ranges from 0.8 to 1.2%. Antimony ores occur in the south, the Hilgrove deposits, and in the state of Victoria, the Costerfield deposits.
Gold deposits are located in the west of the country, Norsmen, Telfer with reserves of up to 3.8 thousand tons and content precious metal up to 9.5 g/t, Kalgoorlie deposits. The ore-bearing layers here are rich quartz veins of Upper Archean deposits and zones of active hydrothermal influences.
The quartz-dolomite ore occurrences in the Telfer deposits, near the Pilbara, are mainly found in Upper Proterozoic sediments. Norseman contains gold-sulphide veins and loose ones are being mined sedimentary rocks ancient bark weathering with gold content up to 19 g/t. Gold occurrences were discovered in the Jabiluk uranium deposits.
The country leads the world in discovered reserves and production of uranium. More than 30 deposits of this strategic raw material have been discovered here. The largest of them was the ore-bearing area called Alligator Rivers with a total area of up to 1.5 thousand square meters. km. Here in the north lie up to 3/4 of Australian uranium reserves, and up to 17% of the world's total. The largest deposits of the Alligator Rivers were the geological formations of Nabarleka and Jabeluk, Koongarra and Ranger. All uranium-bearing ores here occur in the vast Pine Creek geosynclinal region.
Oil and gas Australia
On Australian continent and its shelf, up to 130 rich deposits of natural gas and high-quality oil have been explored and are partially being developed. The largest among them, with reserves of up to 50 million tons, were the Marlin, Barracouta and Kingfish deposits. They are located in the pericontinental sedimentary basin called Gippsland in the waters of the vast Bass Strait.
The country ranks second in the world in brown coal deposits, sixth in reserves of high-quality hard coals. Coals occur in the east of the country in Permian and Triassic deposits. The largest of these were the Sydney area with proven reserves of up to 85 billion tons and the Bowen field in Queensled with reserves of up to 42 billion tons.
Among brown coal basins, the Latrobe Valley is the leader with proven reserves of up to 115 billion tons. The country has large geological deposits of oil shale. They are found here in ancient Mesozoic deposits. Large deposits are located in Queensland and Tasmania respectively.
Non-metallic minerals
The country is rich in deposits of heavy sands formed on coastal marine placers, the largest deposits being Southport, Capel-Bunbury and Eniba. These sands are rich in zirconium, titanium and other rare earth minerals. The country has deposits of precious and semiprecious stones. The country is most famous for its precious opals and sapphires.
The largest deposits of precious opals, discovered in the 19th century, were Andamooka and Coober Pedy, in Queensland, Heirix and Yovah. The main source of excellent quality black opals was the Lightning Ridge deposits. Famous Australian sapphires are mined in alluvial placers in Queensland near the town of Anakie, in South Wales near the cities of Glen Innes and Inverell. Other stones are chrysoprase, rhodonite and jades.
The continent is very rich in phosphorites; the country confidently ranks fourth in the world in the extraction of this most valuable raw material for industrial development. Deposits of phosphorite raw materials were formed among the Cambrian sedimentary deposits of the Georgina Basin in Queensland. The largest deposit of phosphorites was recently explored and actively exploited today, Duchess with total reserves of 1418 million tons and a useful P2O5 content of up to 18%. Chrysotile asbestos, talc, barite, graphite, gypsum, muscovite, potassium salts, building materials, sand, clay and gravel are also mined.
The topography and mineral resources of Eurasia are extremely diverse. Geomorphologists often call this continent a continent of contrasts. Geological structure, the topography of the continent, as well as the distribution of minerals in Eurasia will be discussed in detail in this article.
Mainland Eurasia: geological structure
Eurasia is the largest continent on our planet. 36% sushi and about 70% earth's population concentrated right here. Almost all the continents of the Earth, in fact, are fragments of two ancient supercontinents - Laurasia and Gondwana. But not Eurasia. After all, it was formed from several lithospheric blocks, which for a long time came closer together and, finally, were welded into a single whole by locks of folded belts.
The continent consists of a number of geosynclinal areas and platforms: East European, Siberian, West Siberian, Western European and others. In Siberia, Tibet, and also in the area of Lake Baikal Earth's crust cut by a huge number of cracks and faults.
In different geological epochs Eurasia arose and took shape. Pacific and Alpine-Himalayan are the largest of them. They are considered young (that is, their formation has not yet finished). It is these belts that include the largest mountain systems of the continent - the Alps, the Himalayas, Caucasus Mountains and others.
Some areas of the mainland are areas of increased seismic activity (such as central Asia or Powerful earthquakes are observed here with considerable frequency. Eurasia can also boast of having the largest number of active volcanoes.
The continent's mineral resources are closely related to its geological structures. But we will talk about them later.
General features of the relief of Eurasia
The topography and mineral resources of Eurasia are extremely diverse. They formed in the Mesozoic and Cenozoic, within several ancient platforms connected by mobile folding areas.
Eurasia is the second highest continent on the planet with an average altitude of 830 meters above sea level. Only Antarctica is higher, and even then solely due to its powerful ice shell. The highest mountains and the most large plains are located precisely in Eurasia. And in total there are much more of them than on other continents of the Earth.
Eurasia is characterized by the maximum possible amplitude (difference) of absolute heights. It is here that the highest peak of the planet is located - Mount Everest (8850 m) and the most low point world - level Dead Sea(-399 meters).
Mountains and plains of Eurasia
Almost 65% of the territory of Eurasia is occupied by mountains, plateaus and highlands. The rest belongs to the plains. The five largest mountain systems of the continent by area:
- Himalayas.
- Caucasus.
- Alps.
- Tien Shan.
- Altai.
Himalayas - the highest mountain range not only Eurasia, but the entire planet. They borrow about 650 thousand square kilometers area. It is here that the “roof of the world” is located - Mount Chomolungma (Everest). Throughout history, 4,469 climbers have conquered this peak.
This continent is also home to the Tibetan Plateau, the largest in the world. It occupies a huge area - two million square kilometers. Many famous ones originate here (Mekong, Yangtze, Indus and others). Thus, this is another geomorphological record that Eurasia can boast of.
The minerals of Eurasia, by the way, often lie precisely in folding zones. So, for example, the depths of the Carpathian Mountains are very rich in oil. And in the mountains of the Urals, precious minerals are actively mined - sapphires, rubies and other stones.
There are also many plains and lowlands in Eurasia. Among them is another record - the East European Plain, which is considered the largest on the planet. It stretches from the Carpathians to the Caucasus for almost 2,500 thousand kilometers. Within this plain, in whole or in part, twelve states are located.
Relief of Eurasia: highlights and interesting facts
Behind the impressive orographic records it is very easy to miss smaller, but no less interesting features mainland. The relief of Eurasia contains, in fact, all known modern science relief forms. Caves and karst mines, karsts and fjords, ravines and river valleys, dunes and dunes - all this can be seen within the very large continent Earth.
In Slovenia there is the famous Karst plateau, the geological features of which give the name to a whole group of specific landforms. Within this small limestone plateau there are several dozen beautiful caves.
There are many volcanoes in Eurasia, both active and extinct. Etna, Vesuvius and Fuji are the most famous of them. But on the Crimean Peninsula you can see unique mud volcanoes (on the Kerch Peninsula) or so-called failed volcanoes. A striking example the latter is the well-known mountain Ayu-Dag.
Mainland minerals
Eurasia ranks first in the world in terms of total reserves of many mineral resources. In particular, the bowels of the continent are extremely rich in oil, gas and non-ferrous metal ores.
In the mountains, as well as on the shields (protrusions of the foundation of platforms) of Eurasia, significant deposits of iron and tin, tungsten, platinum and silver are concentrated. Huge reserves of fuel mineral resources - oil, gas, coal and oil shale - are confined to the deflections of the foundations of ancient platforms. Thus, the largest oil fields are being developed in the Persian Gulf, in Arabian Peninsula, on the North Sea shelf; natural gas - in Western Siberia; coal - within the East European Plain and in Hindustan.
What else is Eurasia rich in? Non-metallic minerals are also extremely common on the mainland. Thus, on the island of Sri Lanka there is the world's largest deposit of rubies. Diamonds are mined in Yakutia, granite of the highest quality is mined in Ukraine and Transbaikalia, and sapphires and emeralds are mined in India.
In general, the main mineral resources of Eurasia are oil, gas, iron ore, manganese, uranium, tungsten, diamonds and coal. The continent's production of many of these resources is unparalleled in the world.
Minerals of Eurasia: table and main deposits
It is worth noting that the continent’s mineral resources are distributed extremely unevenly. Some states are frankly lucky in this regard (Russia, Ukraine, Kazakhstan, China, etc.), while others are not so lucky (such as Japan). The most important mineral resources of Eurasia are listed below. The table also contains information about the largest deposits of certain mineral resources of the mainland.
Mineral resource (type) | Mineral resource | Largest deposits |
Fuel | Al-Ghawar ( Saudi Arabia); Rumaila (Iraq); Daqing (China); Samotlorskoye (Russia) |
|
Fuel | Natural gas | Urengoyskoye and Yamburgskoye (Russia); Galkynysh (Turkmenistan); Aghajari (Iran) |
Fuel | Coal | Kuznetsk, Donetsk, Karaganda basins |
Fuel | Oil shale | Bazhenovskoe (Russia), Boltyshskoe (Ukraine), Mollaro (Italy), Nordlinger-Ries (Germany) |
Iron ore | Krivoy Rog (Ukraine), Kustanay (Kazakhstan) basins; Kursk Magnetic Anomaly (Russia); Kirunavara (Sweden) |
|
Manganese | Nikopolskoe (Ukraine), Chiaturskoe (Georgia), Usinskoe (Russia) |
|
Uranium ore | India, China, Russia, Uzbekistan, Romania, Ukraine |
|
Oktyabrskoye and Norilskoye (Russia), Rudna and Lubin (Poland) |
||
Nonmetallic | Russia (Siberia, Yakutia) |
|
Nonmetallic | Russia, Ukraine, Spain, Sweden, India |
|
Nonmetallic | Russia ( Kaliningrad region), Ukraine (Rivne region) |
Finally
The largest continent on our planet is Eurasia. The mineral resources of this continent are extremely diverse. The world's largest reserves of oil, natural gas, iron and manganese ore are concentrated here. In the bowels of the continent there is a large number of copper, uranium, lead, gold, coal, precious and semi-precious stones.
And fuels, forestry industry. Acting as exporters of products from these industries, South American countries to a large extent depend on their prices on the world market.
A peculiarity of the economic development of the countries of South America is the reduction in the share of agriculture in the gross domestic product and the increase in the share of industry: from 1960 to 1980, the former decreased from 17 to 11%, and the latter increased from 21 to 26%.
Among the countries of South America, the so-called new industrial countries, which include Argentina and Brazil, Venezuela is adjacent to them in terms of economic development. The least developed include French Guiana, Paraguay, Bolivia, Guyana, Suriname and Ecuador; Colombia, Chile, Uruguay and Peru occupy an intermediate position. Uruguay and Paraguay belong to the category of countries where agriculture and the industry for processing agricultural raw materials are predominantly developed. Big role Mining plays a major role in the economy of most South American countries. Its share in the gross domestic product ranges from 1% (Brazil), 1.5% (Colombia), 2.5% (Argentina) to 8% (Bolivia), 9-10% (Suriname, Guyana, Chile, Peru, Ecuador ) and 16% (Venezuela). The share of mining in total industrial production is much higher: from 4.5% for Argentina to 25-30% for Bolivia and Venezuela; in Peru and Chile, mining is the main branch of industrial production. Based on the structure of the mining industry, we can distinguish countries associated primarily with the extraction of energy (Venezuela, Colombia, Argentina, Ecuador) and metal (Bolivia, Guyana, Suriname, Peru, Chile, Brazil) raw materials. A significant part of the extracted raw materials and fuels is processed locally (in Venezuela, copper ore in Chile, base metals in Peru, tin in Bolivia, etc.), while at the same time a significant part of the mined iron ore and bauxite is exported in raw form. The share of domestic consumption of produced metals is relatively small. With annual steel production on the continent of 28.3 million tons (1986), the countries of South America export 10 million tons of ferrous metals with annual imports of 3-4 million tons. Mineral raw materials, fuel and products made from them are one of the main export items, accounting for a significant part (over 10%) of foreign trade turnover. In addition to energy raw materials, primarily oil, which provides 80-90% of the total value of exports of raw materials and fuels, over 90% of mining and metallurgical exports are provided by copper, iron ores, bauxite, tin, lead and zinc, silver, tungsten, molybdenum and antimony.
At the latitude of the Amazon Valley, the Northern Andes are separated from the Central Andes by a constriction. The latter are divided into two segments: the northern segment with a northwestern strike occupies mainly the territory of Peru, the southern one is meridional; within its borders are Bolivia and parts of the territory of Chile and Argentina. Northern section Central Andes consists of two main ridges - the cordillera-anticlinoria, Western and Eastern, between which the Sierra Blanca massif, formed by a young granite batholith, is wedged. On the coast Southern Peru in the Arequipa massif, early Precambrian rocks emerge, proving that the Central Andes are entirely underlain by ancient continental crust. The Eastern Cordillera of Peru and its continuation in Bolivia are composed mainly of folded terrigenous Paleozoic complex. In the cores of the uplifts, the green-schist Upper Proterozoic complex is exposed, separated by a sharp unconformity from the Paleozoic; the main deformations of the latter occurred in the Late Devonian and Permian. The Upper Paleozoic and Triassic are represented by continental volcanics and molasse. On the wings and in individual synclines, shallow-water and continental chalk deposits are preserved in the south. The Western Cordillera is formed mainly by calc-alkaline volcanics and granites of Cretaceous and early Paleogene age. In the south, within its borders there is a group of young volcanoes. In the trough between the Cordillera and to the east of the latter, mainly shallow-water carbonate-terrigenous chalk deposits, devoid of manifestations of volcanism, are common. In the south, in Bolivia, the space between the Cordilleras is occupied by the Altiplano graben, filled with a thick sequence of predominantly continental clastic sediments of the Cretaceous-Cenozoic. On the sides of the graben are Neogene subvolcanic intrusions. In the south, the eastern part of the Bolivian Andes is adjacent to the Sierra Pampa massif with a block structure; Upper Proterozoic metamorphites and Paleozoic granites emerge in horsts; grabens are filled with continental Cenozoic. In the southern segment of the Central Andes, a significant role in the structure of the Western Cordillera belongs to the Jurassic marine “porphyrite” series; in the upper Jurassic it is replaced by terrestrial volcanics, continuing in the Cretaceous and Paleogene deposits; they form a single volcanoplutonic belt with coeval granites. In the south it is answered by the Main Cordillera of Chile and Argentina; from the west it is accompanied by Paleozoic strata with ophiolites of the Advanced Cordillera and Precordillera of Argentina. In the Coastal Cordillera of Chile, Paleozoic metamorphites and granites appear on the surface.
The border between the Southern (Patagonian) and Central Andes is unclear. In the south folded mountain system turns east, continuing into Tierra del Fuego and, already under water, towards the island of South Georgia. Here, between the Patagonian Cordillera composed of Paleozoic and young granites and the Cretaceous-Early Paleogene flysch zone, a sequence of Late Jurassic-Early Cretaceous ophiolites, considered as formations of a marginal sea, is wedged. Ophiolites and flysch are gently thrust over the Cenozoic molasse of the Magellanic foredeep.
The Bolivian tin-silver belt is distributed in an area composed of Paleozoic geosynclinal and platform deposits, intruded by subvolcanic granodiorites, dacites and rhyolites, which are associated with endogenous mineralization. In the recent past, it was the richest silver province with such unique deposits as Potosi, from the depths of which 35 thousand tons of silver have been extracted since 1544. The ore veins of this deposit are concentrated around a porphyry stock. The veins have been traced to a depth of 875 m, but high-grade ores are concentrated in their upper parts to a depth of 350 m. Now the main thing is practical significance have deposits of tin ores of the sulfide-cassiterite formation.
The oil and gas belt of the Eastern foothills, as well as the intermountain troughs of the Andes, filled mainly with Cenozoic molasse, contain numerous deposits of oil and combustible gas, especially significant in the territory of Venezuela.
Traps and ring intrusions of ultramafic alkaline rocks with rare metal carbonatites of Cretaceous and Paleogene age are known in the Andes and beyond.
Numerous coal deposits, mainly of Jurassic, Cretaceous age, are also associated with the Mesozoic-Cenozoic era. Among them are coal deposits of the intermountain depressions of the Andes (for example, Bogota in Colombia, Beblian in Ecuador, etc.), a chain of lignite deposits of predominantly Tertiary age in the eastern foredeep of the Andes (Venezuela, Colombia, Argentina) and individual deposits in the platform cover (Aosta Amazon in Brazil, etc.). 51 oil and gas bearing basins are known to the young weathering crust of the water area. total area 8.1 million km 2, including 2 million km 2 of water area. Commercial oil and gas potential has been established in 28 basins, and production is ongoing in 25 of them. Proven hydrocarbon reserves at the beginning of 1989 amounted to 18.2 billion tons of oil and 7.3 trillion. m 3 of gas (about 90% associated). At the same time, the overwhelming majority of oil and gas reserves are concentrated in two basins: the Maracaiba (44% oil and 34% gas) and the Orinoco (36% oil and 32% gas). The productive horizons of these basins are associated with Cenozoic and Cretaceous sediments. The main proven hydrocarbon reserves are concentrated in the depth range of 1-3 km (70% of oil reserves and 80% of gas reserves). Among the countries of South America, Argentina, Bolivia, Brazil, Venezuela, Colombia, Peru, Suriname, Chile and Ecuador have proven oil and gas reserves. The most significant hydrocarbon reserves are in Venezuela, Argentina, Brazil, and Colombia. The first oil fields were discovered in Peru in 1863 (Sorritos) and 1868 (La Brea Parinhas). Systematic searches in most countries of South America began in the 40s. 20th century By this time, about 100 oil fields had been discovered on the continent, including the unique Bolivar oil and gas accumulation zone. The search and exploration of hydrocarbons was carried out mainly by foreign companies. In the 40-50s. The first deposits were discovered in Brazil and Chile in the 60s. industrial oil and gas potential has been proven eastern regions Colombia, Ecuador, Peru (Upper Amazonian oil and gas basin). In the 50s Shelves are also involved in oil exploration work. The first deposit on the Pacific shelf was discovered in 1955 (Litoral, Peru), and on the Atlantic shelf in 1968 (Guarisema, Brazil). The main volumes of oil exploration work occur in the oil and gas basins of the Pre-Andean trough (Argentina, Colombia, Peru, Ecuador) and the Atlantic pericontinental basin (Brazil, Argentina). At the beginning of 1989, 1,400 oil (including 140 offshore) and 252 gas (including 40 offshore) fields were discovered in South America. Among them are the Venezuelan oil fields, unique in terms of reserves (more than 1 billion tons) - Bachachero, Lagunillas, Tia Juana (included in the Bolivar zone), giant cluster heavy oils - the Orinoco Belt (reserves of 4.2 billion tons), Lamar and Lama, with reserves of more than 300 million tons, as well as the unique deep-water oil fields of Brazil - Marlin (500 million tons of oil and 100 billion tons). m 3 of gas) and Albacore (342 million tons of oil and 150 billion m 3 of gas).
The total reserves of coal of all types in the countries of South America at the beginning of 1987 are estimated at about 52.8 billion tons (39.9 billion tons of hard coals and 12.9 billion tons of brown coals). Explored reserves amount to 15.4 billion tons (14.2 billion tons of hard coal and 1.2 billion tons of brown coal). The largest total reserves are found in Brazil, Colombia, Venezuela, and Chile.
The carbon content of South America is associated with sediments of a wide age range- from Devonian to Quaternary, but the main industrial importance is for coal seams of Permian (Brazil), Cretaceous (Colombia, Peru) and Paleogene-Neogene (Colombia, Venezuela, Chile, Argentina) age. Coal-bearing sediments of Permian (possibly, partially Late Carboniferous) age are distributed mainly in the sediments of the cover of the South American platform, and Mesozoic-Cenozoic ones are found in the folded belt of the Andes. The coal basins of Rio Grande do Sul, Santa Catarina (Brazil), Bogota, Boyaca (Colombia), Zulia (Venezuela), Concepcion, Magellanes (Chile) and the Cerrejon (Colombia) and Rio Turbio ( Argentina). Lignite basins in South America are insignificantly widespread (Bolivia, Brazil) and are practically not developed. South American coals are mainly medium- and high-ash, mostly energy-grade non-coking or low-coking.