Almost all of Africa is part of the ancient continent of Gondwana, formed in the Precambrian (Archean, Proterozoic). The modern foundation - the foundation of the African continent - is the African one. It is composed mainly of hard crystalline, igneous and metamorphic rocks. In the zones of subsidence (troughs), the platform is covered by a cover of sedimentary deposits, which occupy 2/3 of the mainland. In the zones of uplifts, on shields and anticlips, the platform foundation comes out to the surface. The largest shields and anticlyzes of the Archean-Proterozoic basement are the Ahaggar, Leono-Liberian, Nubian-Arabian, Central African, and others massifs. The most significant protrusions of the ancient basement are located along the eastern edge of the continent (Ethiopian Highlands and East African Plateau). Here passes the world's greatest system of East African rifts - rifts, stretching 6500 km from the lower reaches, through the East African Plateau and the Ethiopian Highlands to the Gulf of Aqaba in.
Within African Platform geologists distinguish between a plate (part of the wider Sahara-Arabian plate) and the South African shield. The border between them is drawn from the massif to the Red Sea. The Sahara Plate and the South African Shield have evolved in different ways. Therefore, their modern relief is significantly different. In the northern part of the continent, on the Sahara plate, deep depressions alternate - (for example, Libyan), high stepped and plateaus, destroyed ancient highlands (Ahaggar and Tibesti). The northern part of the mainland is called Low, since the heights of the terrain here do not exceed 1000 m.And some depressions lie much below sea level: Assal in (-153 m) and the Qattara depression in the Libyan
(-133 m). During the entire post-Proterozoic period, the South African shield experienced predominantly uplift. Therefore, its territory has prevailing heights of more than 1000 m. This is already High africa, where highlands and plateaus, horsts and grabens, high lava plateaus and massifs alternate. Within the East African Plateau, the volcanic massif Kilimanjaro rises to a height of 5895 m - highest point mainland.
In the extreme northwest and extreme south of the continent, the mobile folded zones adjoin the African platform - the Atlas zone in the north and the Cape zone in the south. Folding movements in the Cape Mountains ended during the Hercynian orogeny, and in the Atlas Mountains during the Alpine. At present, they are low and medium-altitude folded-block mountains dissected by river valleys.
In general, Africa is quite high mainland... In terms of average altitude (750 m above sea level), it is inferior only to and. Mountainous areas occupy slightly more than 20% of its area, lowlands - less than 10%; 70% of Africa's territory falls on high stepped plains, plateaus, plateaus and highlands.
Africa is a unique continent in terms of diverse reserves. It accounts for (in relation to the reserves of foreign): 97% of the reserves of platinum group metals, 95% - chromites, 92% - diamonds, 81% - manganese ores, 68% - phosphorites, 62% - gold, 40% - bauxite and many other resources. If the ores of ferrous, non-ferrous and rare metals, as well as diamonds, are confined mainly to the Precambrian basement of the mainland and are mined in Central and South Africa, then in sedimentary rocks in the north of the mainland and on the coast of the Gulf of Guinea, significant reserves of oil and, as well as phosphorites, have been explored, bauxite, manganese and sedimentary ores.
Africa is the second largest continent of the Earth after Eurasia. Its area is 30.3 million km2. Africa occupies a special geographical position among other continents. Almost in the middle, it is crossed by the equator and is located mainly between the North and South tropics. The initial (zero) meridian passes in the west. Thus, Africa is located, on the one hand, in the Northern and Southern Hemispheres, on the other - in the Western and Eastern Hemispheres. This land giant in area belongs to the group of so-called southern continents which have many similarities. Africa stretches 8000 km from north to south. The widest part of the continent is in the Northern Hemisphere.
The shores of Africa are washed by the waters of the Atlantic and Indian Oceans. On the west coast Atlantic Ocean forms the large Gulf of Guinea. Along west coast a narrow (up to 100 km) continental shelf stretches.
In the east in Indian Ocean the only major peninsula in Somalia stands out. The islands off the coast of Africa are few in number. The largest of them - Madagascar is separated from the continent in the east by the Mozambique Strait. V tropical latitudes West Coast the mainland is washed by the cold Canary and Benguela currents, and the east - by the warm Mozambican current. The African continent is closely linked to Eurasia. They are separated by the Straits of Gibraltar and Bab-el-Mandeb, the Mediterranean and Red Seas, and the Suez Canal. Africa and Eurasia are a single land mass in the Eastern Hemisphere, separated from other continents by vast oceanic expanses.
The geographical position of Africa determines high temperatures air on its most part and contributes to the vivid manifestation of geographic zoning in its territory.
Geographical exploration of Africa
(Using the thematic map of the atlas, determine which regions of Africa were most explored in the nineteenth century.) Research in Africa has been uneven. The southern regions of Africa, in comparison with the northern ones, became known to Europeans much later. Research in Africa was associated with the search for a sea route to India, and from the 15th century. - with the development of the slave trade. In search of a way to India, B. Dias was the first to go around Africa from the south. Later (1497-1499) Vasco da Gama, circling the cape Good Hope and examining East Coast Africa, reached the shores of India. To expand their possessions, England and France are organizing a number of expeditions. The vast interior regions became known to Europeans only from the middle of the 19th century.
In the nineteenth century. great contribution to the research of the South and Central Africa contributed by the English naturalist David Livingston. He studied the animal and vegetable world, natural features travel areas. D. Livingston was the first to describe the geology and topography of South Africa, he explored the Kalahari Desert, a number of lakes, including the Nyasa and the Zambezi River. Having lived in Africa for thirty years, D. Livingston has established himself as a humane and noble researcher, single-handedly fought the slave trade.
Henry Stanley's Anglo-American Expedition explored Lakes Victoria and Tanganyika and established their outlines, discovered mountain range Rwenzori, recognized the Kagera River as the main tributary of Lake Victoria. G. Stanley corrected the mistake of D. Livingstone, who had previously taken the source of the p. Congo for the source of the river. Nile.
Among Russian researchers, V.V. Juncker occupies a special place, having collected interesting information about the nature of Central and East Africa in late XIX c .. A physician by training and a geographer by vocation, V. V. Juncker traveled across the continent for ten years at his own expense. He described plant and animal world rainforest and savannah, conducted meteorological observations, for the first time made a map of the watershed area of the great African rivers - the Nile, Congo and Niger. NI Vavilov, studying the centers of origin of cultivated plants, in the 20s. XX century. organized scientific expeditions to study Mediterranean vegetation (Algeria, Tunisia, Morocco, Ethiopia). In the second half of the XVI century. Nikolay Radziwill (Orphan) visited Africa.
The structure of the earth's crust and relief of Africa
At the base of most of the mainland lies the ancient African-Arabian platform. Under the influence of tectonic movements and external processes for a long geological time, the surface of the continent was leveled: sections of the platform rose and fell, the raised sections collapsed, and the depressions were filled with sediments. This is what determined the modern forms and features of the relief, the presence of minerals on the continent. The relief of Africa is represented mainly by elevated plains, and Eastern- plateaus and highlands.
The sedimentary cover over the platform basement is more developed in North Africa(Sugar Plate). Deflections of the crystalline basement lie at the base of the Congo, Kalahari, Karu depressions. The highlands of Ahaggar, Tibesti, the North Guinean and South Guinean uplifts, and the East African plateau are confined to the uplifts and outcrops of the crystalline basement - the shields.
A significant part of the continent's area is occupied by the East African Plateau and the Ethiopian Highlands. They were formed under the influence of internal processes (uplifting and spreading), which contributed to the fact that certain parts of the platform rose. The movements were accompanied by faults in the earth's crust with the formation of horsts and grabens, and volcanic eruptions. Thus, large lava sheets were formed on the Ethiopian Highlands. As a result of tectonic processes in the eastern part of the continent, linearly elongated tectonic structures - rifts were formed, which stretched along the Red Sea through the Ethiopian Highlands to the river. Zambezi. Individual cracks gradually expanded and filled with waters, forming deep and elongated lakes: Tanganyika, Nyasa, Rudolf, Edward, Albert. This area is called the East African Rift Zone.
Here is the most high peak Africa - Kilimanjaro volcano (5895 m) and the lowest place on the mainland - Lake Assal (157 m below sea level).
In the north and south of the continent, folded areas formed in different geological periods adjoin the African-Arabian platform. These are mountainous areas: in the north - young folded mountains Atlas, included in the Alpine-Himalayan fold belt, and in the south - the more ancient dilapidated Cape Mountains. In the era of the last mountain building, the outlying parts of the continent were uplifted, as a result of which the blocky flat-topped Drakensberg Mountains were formed. Lowlands (Senegalese, Mozambique, etc.) are found along the coast of Africa and in river valleys.
Minerals of Africa
Africa is rich in a variety of minerals. Their placement is due to the structure of the earth's crust and the geological history of its development. The sedimentary cover of the Sahara Plate and the coastal lowlands of the Gulf of Guinea are rich in oil reserves (Algeria, Libya, Egypt, Nigeria). On crystal shields the rich are revealed ore deposits... To the west of the East African Plateau stretches the famous African copper belt. Deposits have been explored in northern Africa iron ore, in the basins of the Congo and Orange rivers - manganese.
Gold reserves are located in the south of the continent - in South Africa. TO ancient foundation mainland within Eastern and Southern Africa are timed largest deposits iron ores, chromites, gold, diamonds and uranium ores. In places of ancient volcanism in South and East Africa, diamond deposits (kimberlite pipes) were formed. In South Africa, the sedimentary strata contain large reserves of coal. Oil and phosphorite deposits have been discovered in the Atlas fold area.
Africa is crossed almost in the middle by the equator and most of it is located between the tropics. This explains her hot climate... A notable contribution to the study of Africa was made by Russian researchers - V.V. Yunker (meteorological observations and the study of flora and fauna), N.I. Vavilov (study of vegetation).
7th grade. Geography of continents and oceans.
Lesson № 19. Theme: Geological structure, relief and minerals of Africa. East African crustal faults.
Targets and goals:
educational: study the features of the relief of the mainland, identify the reasons for these features. To concretize the already known regularity of the placement of large landforms. Teach compilation brief characteristics large landforms according to plan. Consider the patterns of placement of mineral deposits, explain the reasons for their location. Name and show large landforms, mineral deposits in Africa.
developing: development of mental activity of students when working with information sources, cartographic material; development of attention, memory, imagination.
educational: develop the ability to listen to your classmates.
Lesson equipment : physical map of the world, “Geography. Our home is Earth. Continents. Oceans. Peoples. Country. 7th grade".
Main content ... The sequence of studying the relief (plan). Prevailing landforms, the history of their formation and mutual arrangement. Differences in topography between High and Low Africa; reasons for the differences. Mineral resources and patterns of distribution of their deposits on the mainland.
Basic concepts and concepts ... Relief, platform, internal and external relief-forming processes, volcano, highlands, minerals.
Methods and forms learning activities ... Heuristic conversation based on card analysis and comparison. Problematic presentation of the question of the formation of the relief of the continent. Working with nomenclature using atlas maps. Student work at outline map... Advance student messages on the relief and minerals of Africa. Description of individual relief forms based on maps and other sources of knowledge.
During the classes
Organizing time.
Updating basic knowledge and students' skills:
Conversation on questions and tasks:
1.What is the main feature geographic location Africa?
2.Name extreme points the mainland, the seas washing it, the elements coastline, islands of the peninsula.
3.What is relief? Under the influence of what factors is it formed?
4. What types of minerals do you know?
Motivation of educational and cognitive activities of students
Today we will continue our journey across mainland Africa.
Teacher:
It is washed by two oceans
There are many rivers and different countries on it.
The Sahara Desert is there
A caravan is going through the sand dunes.
There are the Atlas Mountains, and Algeria is nearby.
The Nile begins from the blue lakes.
There is a Kalahari with a colored river
Feed the animals with your water.
The next stage in the study of the features of the African continent is the characterization of its relief and the determination of the patterns of the location of mineral deposits.
Learning new material.
-Teacher's story ... The history of the development of the earth's crust in Africa began with the ancient continent of Pangea, from which two continents were formed - Laurasia and Gondwana. It was from the latter that Africa was formed at the beginning of the Mesozoic, South America, Australia and Antarctica.
-Single work in order to gain new knowledge and generalize the material:
Working with a tectonic map : determine which ancient structures formed this continent and indicate territorial differences, plot them on a contour map of Africa.
Working with maps: "Physical map of Africa", "Map of the structure of the earth's crust."
Practical work:
1. Analysis of the physical map and its comparison with the map of the structure of the earth's crust.
Mainland relief characteristics plan:
1) the prevailing form of relief in height and their mutual placement;
2) predominant types of plains in height;
3) predominant types of mountains in height.
Working with the tutorial p. 69 "The Great East African faults."
1. What tectonic structure lies at the heart of mainland Africa?
2. What is the cause of the faults?
3. How will the relief and, in the future, the area of Africa change?
Conclusion: the ancient African-Arabian platform lies at the heart of the continent, hence the predominance of plains; a smaller area is occupied by folded belts, therefore, mountains occupy a smaller area.
Description of one of the relief forms according to the plan.
1) In what part of the mainland is the landform located?
2) In which direction does it stretch?
3) What are the approximate dimensions?
4) What are the highest, prevailing heights?
5) What is the origin of the landform?
Practical work : “Landforms, their structure and age; characteristic minerals ".
What minerals is Africa rich in and what are the patterns of their distribution? Draw them on a contour map.
V ... Consolidation of the material studied in the lesson.
Find out by description:
1. This geographic feature Africa is part of the African Platform. Its slopes are covered with hard-leaved forests. It is located south of the tropics. Maximum height 3482m. More precipitation falls on the eastern slopes. It is washed by the current of Cape Igolny. Citrus fruits, olives, peanuts are grown from cultivated plants.
2. There is a fault line here. Earthquakes are frequent. Dozens of volcanic cones rise above the area. In the west and south, the slopes are steep and steep. The altitudinal zonality is well expressed. Above 1800 meters evergreen forests replaced by savannas. Here is one of the sources of the Nile. (Ethiopian Highlands).
VI ... Conclusions on the topic of the lesson:
1) Almost the entire mainland is the ancient African-Arabian platform - part of the split Gondwana.
2) The northern and southern parts of the continent developed in different ways, therefore, their modern relief is significantly different.
3) In the north more zones subsidences repeatedly flooded with seas. Therefore, deposits of sedimentary origin are widespread: coal, salts, manganese ores.
4) In the south and east, plateaus and highlands are located on the shields. Block fault zone. Vertical and horizontal movements of large blocks of the earth's crust occurred along the cracks. Formed horsts (uplifts) - blocky ridges of the East African plateau, grabens (subsidence) - Drakensberg mountains. Gold, diamonds, uranium ores are mined.
5) Coast of the Gulf of Guinea (outcropping of ancient crystalline rocks) - significant reserves of oil and gas.
VI ... Homework: to learn § 15; assignment in a contour map: indicate large landforms and minerals of Africa. Indicate the boundaries of the Great Rifts.
Quest for the curious : 1.The average height of Africa is 650 m above sea level, but there are points, absolute height which reaches 4.5 thousand meters and more.
2. Name the four highest points in Africa, the name of which begins with the letter "K".
3. Make a cluster with the word "Africa".
Literature
1. Pestushko V.Yu., Uvarova A.Sh .. Geography of continents and oceans. Ed. "Genesa", K., 2007.
2.Kobernik S.G., Skuratovich O. Ya. Geography of continents and oceans. Textbook for grade 7. K., 2002.
3.Korneev V.P. Geography of continents and oceans. 7th grade. A guide for teachers. "Ranok", H., 2002.
4.Dovgan G.D. Geography of continents and oceans. 7th grade. "My synopsis", H. "Osnova", 2012.
Slide 2
Targets and goals
- To form in students an idea of the tectonic structure, relief and minerals of Africa - their composition, structure, location.
- Continue the formation of the ability to establish causal relationships, work with geographical maps and compare them.
Slide 3
Repetition of the covered material
- What is the area of Africa? (Second in the world)
- How many hemispheres is Africa located in? (At four)
- What is Almadi? (Cape)
- Which cape is extreme southern point Africa? (Needle)
- What is the closest continent to Africa? (Eurasia)
- Which strait separates Africa from Europe? (Gibraltar)
- North Cape of Africa. (Ben-Secca)
Slide 5
- What is the name of the famous explorer?
- He crossed South Africa from west to east, explored the Zambezi River, discovered a large beautiful waterfall, named by him Victoria.
- Who led the expedition, which from 1926 to 1927. collected 6000 samples of cultivated plants in Africa?
- David Livingston
- Nikolay Ivanovich Vavilov
Slide 6
Analysis of the card: "The structure of the earth's crust"
- How many lithospheric plates is Africa on?
- Are there areas of collision with other plates? If so, where, and what processes occur during a collision?
- What is the name of the plate and platform on which the mainland is located?
- How old are the mountains on the mainland?
- In what direction and at what speed is the plate moving?
Slide 7
Comparison of tectonic and physical maps
- What is relief?
- Remember the landforms studied.
Slide 8
East African faults
- What landforms prevail in Africa?
- What are the reasons for the diversity of the relief?
- East Africa is home to the largest fault in the earth's crust on land. It stretches along the Red Sea through the Ethiopian Highlands to the mouth of the Zambezi River. Think about what his education is connected with?
Slide 9
Relief
- Where are the young mountains? What are their names?
- Could young mountains have formed in the center of the Sahara?
- Where are the lowlands?
- Where do you see the dependence of landforms on the structure of the continent's crust?
Slide 10
- Plains occupy most of Africa. According to the prevailing heights, the mainland can be divided into Low Africa and High Africa.
- Determine the prevailing heights of Low and High Africa from the map.
Slide 11
Working with a physical map of Africa
By physical map Africa, fill in the missing data.
Slide 12
Atlas mountains
In the northwest of the mainland are the Atlas Mountains, the northern young ridges of which are located at the junction of two lithospheric plates.
Slide 13
Toubkal
The highest peak Atlas is Mount Toubkal (4165 m), a favorite vacation spot for fans of ski tourism.
Slide 14
Kilimanjaro volcano
Kilimanjaro is one of the largest extinct volcanoes in the world, the highest mountain in Africa.
Slide 15
Ethiopian highlands
Ethiopian Highlands - a huge mountain range with chains high mountains and many isolated extinct volcanoes.
Slide 16
Dragon mountains
Drakensberg mountains are similar to a ledge, one slope of which is gentle, and the other is steep, and the steep slope is 2 times shorter than the gentle one.
Slide 17
Minerals
- What part of Africa is rich in ore minerals of magmatic origin, and what part is rich in minerals of sedimentary origin?
- What is the reason for the differences in the location of mineral deposits of different origins?
Slide 18
Output
- Mineral resources of sedimentary origin correspond to the plains, and these are the northern, western and central parts of the continent.
- Mineral resources of magmatic origin correspond to the mountainous relief, and this is the eastern and southeastern parts of the continent.
- Consequently, there is a definite connection between the structure of the earth's crust, relief and minerals, namely: plains and deposits of sedimentary minerals correspond to platforms.
- Mineral resources of magmatic origin are found in the plains, where the crystalline basement of the platform comes close to the earth's surface, as well as along the fault line of the earth's crust.
- The folded areas correspond to mountains and minerals of magmatic origin. Sedimentary minerals are found in the mountains, the formation of which took place on the site of the ancient sea.
Slide 19
Test
- They are located at the junction of two lithospheric plates. 1) Drakensberg Mountains; 2) Cape Mountains; 3) Atlas Mountains;
- The highest point in Africa. 1) Kilimanjaro volcano; 2) volcano Kenya; 3) volcano Cameroon.
- Huge reserves have been discovered in North Africa and on the coast of the Gulf of Guinea. 1) copper ores; 2) diamonds; 3) oil.
- Highlands in eastern Africa. 1) Ahaggar; 2) Ethiopian; 3) Tibesti.
- Mountains in southeast Africa. 1) Drakensberg Mountains; 2) Cape Mountains; 3) Atlas Mountains;
Slide 20
Homework
§25. Draw major landforms and mineral deposits on a contour map.
Slide 21
List of sources used
- Library of electronic visual aids "Geography 6-10 grades"
- Nikitin N.A. Lesson development in geography. 7th grade. - M .: "VAKO", 2005
- http: // site /
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"," Minerals ". They are considered in the physical and geographical characteristics of a region.
Definition 1
Geological structure - this is the structure of a section of the earth's crust, features of bedding of rock layers, their mineralogical composition, origin.
When studying the geological structure of continents, the concepts of "platform" and "folded area" are encountered.
Definition 2
Platform Is a large, relatively immobile area of the earth's crust.
Platforms are at the core of every continent. In the relief, the platforms correspond to the plains.
Definition 3
Folded area - a movable area of the earth's crust, where active mountain-forming processes (earthquakes, volcanic eruptions) are taking place.
In the relief, folded areas are represented by mountain systems.
Definition 4
Relief Is a set of irregularities on the earth's surface.
Definition 5
Minerals - this is the wealth of the earth's interior that can be used by man to meet his needs.
Features of the geological structure of Africa
About $ 180 million years ago, the territory of Africa was an integral part of the ancient supercontinent of Gondwana. When Gondwana split apart, the African lithospheric plate separated. The modern territory of Africa is based on a part of this plate, namely, the ancient (Precambrian) African-Arabian platform .
In most of the territory, active mountain building stopped another $ 1000 - $ 500 million years ago. Later, the hard core of the continent did not experience folded processes.
The lower part of the platform, that is, its foundation, is made up of crystalline rocks - basalts and granites of magmatic and metamorphic origin. They are very ancient in age. As a result of weathering, continental sediments accumulated on the basement, and marine sediments in depressions. Over millions of years, they have formed a powerful sedimentary cover on the platform. It should be noted that the sedimentary cover unevenly covers the basement, because the platform experienced several slow uplifts and subsidences over a long period of time. In those areas where a long process of uplift took place, the ancient crystalline rocks of the basement appeared on the surface, thus forming shields.
Definition 6
The shield is the place where the crystalline basement of the platform exits to the surface.
In other parts of the platform, the processes of subsidence and flooding by waters of ancient seas took place. In these places, the foundation was overlapped by a huge layer of marine sedimentary deposits, and plates formed on such parts of the platform. Millions of years later, the platform in its northwestern and southern parts was "completed" by parts of the ocean floor, while the strata of its sedimentary rocks were crumpled into folds and formed folded areas (area Atlas and Cape mountains ). More than $ 60 million years ago, the African-Arabian platform began to rise intensively. This rise was accompanied by giant fractures in the earth's crust. During these faults, the largest system on land was formed East African faults (rifts) ... It stretches for $ 4000 $ km from the Isthmus of Suez along the bottom of the Red Sea and overland to the Zambezi River. The rift width in some places reaches $ 120 km. The above faults, like a knife, cut through the African-Arabian platform. Along them there are earthquakes, manifestations of volcanism.
Relief of africa
The relief of Africa is dominated by flat areas. This is due to the fact that almost the entire continent is based on a platform. A feature of the African plains is the predominance of high plains:
- hills,
- plateau,
- plateaus.
This can be explained by the general uplift of the entire territory of Africa in the Cenozoic. The lowlands stretch only in narrow strips, mainly along the sea coasts.
The largest plains are located in the northern and western parts mainland. Their surface is very heterogeneous. At the same time, the alternation of uplands with lowlands and plateaus is characteristic of Africa. In places where crystalline basement rocks emerge on the surface, Ahaggar and Tibesti highlands , with a height of more than $ 3000 m. Among the high plateaus (up to $ 1000 m) lies the Congo swampy depression. The Kalahari depression is also surrounded on all sides by plateaus and plateaus.
A relatively small area in Africa is occupied by mountains. The highest marks are East african plateau ... On it are the extinct Kenya ($ 5199 m) and Kilimanjaro ($ 5895 $ m) - the highest point in Africa.
These volcanic mountains are confined to the East African Rift Zone. Ethiopian highlands with numerous extinct volcanoes it is raised by $ 2000- $ 3000 m. It drops off abruptly in the east and descends with ledges in the west. In the northwestern part of the mainland rise Atlas Mountains (or Atlas Mountains), formed at the junction of two lithospheric plates, in the place where Earth's crust was crumpled into folds. In the south of the mainland, low and flat-topped Cape Mountains ... They look like cups turned upside down (hence the name). Dragon mountains - higher, from the coast in giant ledges, they descend to the inland regions of the mainland.
Minerals
The bowels of Africa are rich in a variety of minerals, their location is closely related to the geological structure of the continent. Deposits of ore minerals are confined to the ancient foundation of the platform. In particular, this applies to gold and ores such as:
- iron,
- copper,
- zinc,
- pewter,
- chrome.
The largest deposits are concentrated in the south and east of Africa, in places of shallow bedding. There, in particular, are significant deposits gold and copper , according to the amount of their reserves, Africa occupies the first and second places in the world, respectively. The bowels of the continent are rich and uranium ores ... Africa is famous for its deposits diamonds - valuable precious stones.
Remark 1
They are used not only for the manufacture of expensive and exquisite jewelry, but also as materials, unsurpassed in their hardness. Half of the world's diamonds are mined in Africa.
Their deposits were discovered at southwest coast and in the center of the mainland. Deposits of nonmetallic minerals occur in sedimentary rocks that cover the lowered areas of the platform with a thick cover. These breeds in Africa include:
- coal,
- natural gas,
- oil,
- phosphorites and others.
There are huge deposits in the north of the Sahara and on the shelf of the Gulf of Guinea. Developed deposits of phosphorites, widely used in the production of fertilizers, are located in the north of the continent. The sedimentary strata also contain ore fossils that were formed as a result of the weathering of igneous and metamorphic rocks. For example, in the southern and western regions Africa known deposits iron, copper, manganese ores and gold of sedimentary origin.
