The Congo Basin is the largest (area about 3 million km2), completely closed syneclise of the African Platform. From the north, west and south it is framed by a ring of anteclises of the ancient crystalline basement - flat-topped uplifts, leveled by several cycles of peneplanation: in the north - by the Azande uplift, in the west by the Lower Guinea, intersected by the lower reaches of the Congo, in the south - by the Lunda-Shaba uplift. The Precambrian basement in the Congo Basin is hidden under thick, predominantly continental formations, the accumulation of which began in the Upper Paleozoic and ended in the late Neogene with the deposition of sands similar to the Kalahari sands of South Africa. The deflection was most significant in the center and led to the formation of two “platforms” - lower and upper. The lower - accumulative plain - lies at an altitude of 300-500 m above sea level, the Upper, best expressed in the south and east, forms a gently sloping plateau inward and is located at an altitude of 500-1000 m. The northern part of the depression lies in the equatorial climate zone , the Azande rise and the entire southern part of the country are in the equatorial monsoon climate zone. Continental tropical air brought by trade winds from the northern and southern hemispheres is transformed over the humid hylia into equatorial air. Moist air masses are drawn into the Congo Basin from the oceans: in the summer of the Northern Hemisphere, southwestern monsoons from the Gulf of Guinea penetrate into the western part of the basin, in winter, southeastern trade winds from the Indian Ocean enter its eastern part, retaining a certain amount of moisture up to the level of trade wind inversion . The zenithal position or close to it during the year of the Sun determines uniformly high heating and active convection of moist air masses. Average monthly air temperatures in the equatorial zone fluctuate between 23 and 25? C only on the marginal elevations; at altitudes of more than 1000 m, seasonal fluctuations are noticeably affected: in Shaba, the average temperature of the warmest month is 24? C, the coldest is 16? C. The annual precipitation in the Congo basin is not as high as in the Amazon basin open to the ocean, but still reaches 2000-2200 mm in its central regions. On the windward slopes of the Lower Guinea uplift, the amount of precipitation increases to 3000 mm, and on the slopes of the Cameroon volcano to 10,000 mm - the highest value for Africa. Congo (Zaire), which collects water from a huge basin, is second only to the Amazon in terms of annual flow. The average annual flow rate of about 39 thousand m3/s varies little between seasons. Congo (Zaire) has the largest hydropower potential in Africa (390 million kW) and is the most important shipping artery of equatorial Africa. However, rapids on the main river and its tributaries exclude the possibility of continuous navigation. Railways were built to bypass them in the Congo. The abundance of heat and moisture, the acidic reaction of soil solutions determine the formation of red-yellow alferritic and ferrallitic soils. The western, lowest part of the Congo includes a vast area of hadromorphic soils of tropical swamps. In areas with dry seasons, red soils appear, including lateritic crusts. Vegetation. The distribution of precipitation, the position relative to the rivers and the associated duration of flooding create a wide variety of soil, plant cover and animal life. The flooded marshy areas in the Congo Valley and along the shores of lakes are covered with marsh grasses, among which papyrus predominates. In the drier sandy areas of river valleys you can find pure grasslands with high grass or thickets of low-growing trees. The richest vegetation cover is in non-flooded areas. On thick ancient alluvial soils, as well as on ferrallitic soils formed on the red-colored sediments that make up the watersheds, tracts of primary tropical rainforests have still been preserved, which, although inferior in species richness to the forests of the Amazon and Kalimantan, still represent one of the richest plant formations our planet, consisting of many hundreds of species of trees, vines, epiphytes and other life forms of plants. These forests are a huge source of food and technical resources. These include oil and other palms, rubber trees, nutmeg trees; various tree species with valuable ornamental wood. Animal world. Where primary forests have been preserved, characteristic representatives of the forest fauna can be found. These are chimpanzees and gorillas, timid okapi, hippopotamuses living along the rivers. The equatorial forests of Africa are characterized by the tsetse fly, which is common in the most humid places, near rivers and lakes. Population and environmental problems. For a long time, the central part of the Congo Basin remained the last stronghold of primary tropical rainforests in Africa. But even there they began to disappear catastrophically quickly under the pressure of economic activity: cutting down valuable trees for export, expanding arable areas and pastures. Only in the most remote places live the indigenous population of the tropical forests of Africa - the pygmies, who have retained a wandering lifestyle and are mainly engaged in gathering and hunting. The Congo Basin is closed, including in its lowest part accumulative plains framed by plateaus and slopes of crystalline massifs. It is characterized by constant excess moisture, a dense deep river network, and severe swampiness in the western sector of the low platform. Massifs of evergreen (including periodically flooded) and mixed (with an admixture of deciduous) forests on alferritic and ferrallitic soils occupy watershed hills that are poorly expressed in relief. In the floodplains of valleys that are under water for a long time, they give way to swamps with thickets of reeds and papyrus.
East African. Geographical position. Rising on both sides of the equator, the highlands of East Africa are the most mobile, tectonically active part of the continent with the greatest rift system on earth's land. Trade wind-monsoon air currents coming from the Indian Ocean, diversity in the distribution of precipitation, adjusted by the relief, a vibrant organic world, the abundance of lakes creates an exceptional variety of landscapes compared to the western part of the continent. In the west, the highlands border on the Congo Basin, in the east it approaches the coast of the Indian Ocean, the southern border runs along the lower reaches of the Zambezi, and the northern along the depression of Lake Rudolf. Thus, this region, like the Congo Basin, is mostly located in the southern hemisphere. Geological structure and relief. The closely welded folds of the crystalline foundation of the highland are leveled and raised to 500-1500 m. The relief is dominated by gentle hills and outlier hills, composed of the hardest rocks. A remarkable feature of the relief of the East African Highlands is the rift system, which continues the rifts of the Red Sea and the Ethiopian Highlands. The East African Rift itself passes through Lake Rudolph to the south. The rift's relief is expressed in the form of a giant graben with steep edges up to 600 m deep, with a flat bottom, partially occupied by shallow lakes, swamps and salt marshes. Along the edges of the rift and on the neighboring plateaus rise blocks of crystalline rocks and huge volcanic massifs, the highest in Africa: Kilimanjaro with the peak of Kibo (5895 m), Kenya (5199 m), Elgon (4221 m), etc. Calderas are also typical forms of relief , among which Ngorongoro is the largest caldera on Earth. Volcanic activity along the East African Rift was very intense and has not ended to this day. Climatic conditions. In addition to the equatorial position, a significant role in the formation of the climate types of the East African Highlands is played by the relatively high altitude and dissected relief, as well as the influence of the Indian Ocean. High temperatures, small annual and daily fluctuations are observed only at low altitudes, especially on the coast of the Indian Ocean. With altitude, temperatures become more moderate, their daily fluctuations increase, although the annual cycle remains uniform. In the mountains above 2000 m the temperature is below 0 ° C, above 3500 m snow falls, and on the highest massifs of the equatorial part of East Africa - Rwenzori, Kenya and Kilimanjaro - significant areas are covered with eternal snow and glaciers.
The interior regions are characterized by a typical equatorial precipitation regime with two maximums and two periods of relative reduction. Most rain falls on the western slopes of high massifs, which intercept moisture brought by the southwest monsoons. In the eastern part of the region adjacent to the Indian Ocean, conditions are different atmospheric circulation and precipitation distribution. Trade winds blow over the Indian Ocean throughout the year. In the summer of the northern hemisphere, the southeast trade wind intensifies, its zone of influence moves towards the equator, where it takes on the character of a monsoon. This causes a pronounced wet period along the entire eastern edge of the region, with especially large amounts of precipitation falling on the slopes of high massifs facing east. North of the equator, the northeast trade wind blows here in the summer, resulting in a wet period from November to March. The rest of the year remains relatively dry. Natural waters. The main watershed of Africa lies in the East African Highlands. This is where the Congo and Nile rivers and their large tributaries, tributaries of the Zambezi and other rivers flowing into the Indian Ocean originate. Within the highlands are the largest and deepest lakes in Africa, ranking among the world's greatest lakes. Large masses of water from lakes Victoria, Tanganyika and Nyasa have some influence on the climate. The lakes have long been used for shipping and fishing. Vegetation. The mountainous terrain and diversity in the distribution of precipitation determine the diversity of soils and vegetation. The vegetation cover is dominated by savannas and so-called park vegetation, which is a combination of grassy spaces with small groves and gallery forests. Tropical rainforests occupy incomparably less space than other plant formations. They are distributed almost exclusively at the foothills of high mountain ranges and in the lower parts of their slopes facing humid winds. The largest tracts of these forests are in the west, where they merge with the forests of the Congo Basin. Forests are also common on the northwestern coast of Lake Victoria, at the foot of Rwenzori, Kenya and Kilimanjaro. On the east coast they are found mainly along river valleys and on offshore islands. At an altitude of about 1200 m, the humid forest gradually changes its composition, and up to an altitude of 2000 m the mountains are dominated by a park landscape, in which grassy spaces alternate with groves. Thanks to moderate temperatures and fertile soils, this belt is usually densely populated. Higher up the mountains are covered with dense mountain forests with vines and epiphytes. At an altitude of about 3000 m, forests give way to meadows with giant asteraceae, and from an altitude of 4800 m the belt of eternal snow and glaciers begins. In some areas around lakes and along slowly flowing rivers, swamp vegetation is widespread of approximately the same type as in the White Nile basin. It is represented by dense thickets of reeds, reeds and papyrus with separately rising trees. Animal world. The East African Highlands are famous for their rich and diverse fauna. Monkeys, elephants, giraffes, rhinoceroses, buffalos, zebras, and antelopes find abundant food in the endless savannas and forests of the region. The richness of herbivorous animals favors the spread of predators, including lions and leopards. The river and lake thickets and reservoirs are home to hippopotamuses, crocodiles, and a myriad of local and migratory birds nest. Drier places abound with lizards and snakes. Environmental problems. Long-term extermination of the fauna led to a decrease in the number of animals, many species were on the verge of extinction. In East African countries, efforts are being made to protect wildlife and the most interesting natural landscapes. For this purpose, the world-famous national parks and reserves of East Africa have been created.
The East African Plateau is located on both sides of the equator, between the Congo Basin in the west and the Indian Ocean in the east, Eastern Sudan, the Ethiopian Highlands, the Somali Peninsula in the north and the lower reaches of the Zambezi in the south and covers the area from 5° N. w. to 17° south w.
The plateau is a mobile, tectonically active part of the African Plate. The greatest rift system and the greatest heights of the continent are concentrated here. It is composed of Precambrian crystalline rocks, among which granites are widespread. The ancient foundation is covered in places by Paleozoic and Mesozoic, mainly continental sediments.
The plateau remained an elevated area for a long time. In the Cenozoic, enormous tectonic faults and rifts arose. They continue the grabens of the Red Sea and the Ethiopian Highlands and branch south of Lake Rudolf, forming the western, central and eastern fault systems. Rifts are expressed in relief as narrow depressions with steep stepped slopes; along their edges rise high mountain ranges (Rwenzori massif, volcanoes Kilimanjaro, Kenya, Elgon, etc.). Volcanic activity along the faults has not ended to this day. Areas not affected by faults have the appearance of a typical peneplain with island mountains. The plateau also contains extensive basins (Lake Victoria).
Western fault system runs along the western edge of the plateau and includes deep grabens,
occupied by the Albert Nile River valley, lakes Albert (Mobutu-Sese-Seko), Edward, Kivu, Tanganyika. From Lake Tanganyika it stretches through the depression with the endorheic Lake Rukwa, the tectonic basin of Lake Nyasa, the Shire River valley and the lower reaches of the Zambezi. Fault tectonics is especially evident here. This is one of the most seismic zones of the continent and an arena of modern volcanism.
The grabens of Lakes Albert and Lake Edward are separated by the Rwenzori horst massif, the highest peak in Africa (5119 m) after Kilimanjaro (5895 m) and Kenya (5199 m). The massif is composed of gneisses, crystalline schists and intrusions of basic rocks, has glacial forms of Quaternary and modern glaciation (kars, cirques, trough valleys, terminal moraines), giving an alpine character to the relief of its peaks.
Located between the grabens of lakes Eduard and Kivu Virunga volcanic region(seven volcanoes). Here, in addition to active volcanoes, new volcanic cones are also formed. Ancient lavas cover the tectonic trough between the depressions of lakes Kivu and Tanganyika.
Underwater volcanic eruptions occur at the bottom of lakes Kivu and Nyasa
Adjacent to the northern segment of the western fault system from the east is Lake Plateau(Uganda plateau), located between lakes Edward, Albert, Victoria and the White Nile basin. The plateau has an undulating surface, is composed mainly of crystalline rocks and reaches a height of 1000 to 1500 m. The central part of the plateau is swampy
186 Africa. Regional overview
plain with Lake Kyoga. The plateau ends with stepped slopes towards the East Sudanese Basin, and in the east it joins the volcanic plateau of Kenya.
Central fault system serves as a continuation of the Ethiopian graben, running in a meridional direction from Lake Rudolf in the north to Lake Nyasa in the south, where it meets the western fault system.
In the northern part of the central faults, within the volcanic plateau of Kenya, the volcanic relief is especially pronounced. The extinct volcanoes Kilimanjaro, Kenya, Elgon and a group of giant craters rise along tectonic cracks, the edges of which are covered with basalts and tuffs. Among the group of giant craters stands out the Ngorongoro volcano with a huge caldera.
Between the western and central fault systems, on the one hand, and lakes Victoria and Nyasa, on the other, there is Unyamwezi plateau. It is composed of granites and is very swampy. To the east are the Nyasa and Masai plateaus. These are peneplains on a granite base, broken by faults and crowned with rounded crystalline outlier peaks.
Eastern fault system is represented predominantly by one-sided faults. They limit with ledges from the west a narrow coastal lowland, composed mainly of permeable Tertiary sandstones and limestones.
The climate of the East African Plateau is subequatorial, hot, variable-humid, with a clearly defined climatic zone on high mountain ranges. Only in the vicinity of Lake Victoria, on the Lake Plateau, does it approach the equatorial
rial both in terms of the amount and regime of precipitation, and in the even course of temperatures, which, however, due to the high altitude of the area, are 3-5 ° C lower than the average monthly temperatures of the equatorial strip in the Congo Basin.
Within the plateau, trade winds and equatorial monsoons dominate. During the winter months of the Northern Hemisphere, the northeast trade wind, without changing its direction, is drawn into a pressure depression over the Kalahari. Passing over the ocean from Southeast Asia to Africa, it is moistened and produces a small amount of precipitation, mainly orographic. In the summer of the Northern Hemisphere, the south trade wind (southeast wind) intensifies; crossing the equator, it takes on the character of a southwest monsoon. The main wet period is also associated with them; most precipitation falls on the windward slopes of the mountains.
High temperatures are observed only at low altitudes, especially along the Indian Ocean coast. In Dar es Salaam, for example, the average temperature of the warmest month (January) is +28 °C, the coldest month (August) is +23 °C. It becomes cooler with height, although the annual cycle remains uniform. In the mountains at an altitude of more than 2000 m, the temperature is below 0 ° C, snow falls above 3500 m, and on the highest massifs - Rwenzori, Kilimanjaro and Kenya - there are small glaciers.
The moisture content of different parts of the East African Plateau varies. High mountain ranges receive the greatest amount of precipitation (up to 2000-3000 mm or more). From 1000 mm to 1500 mm of precipitation falls in the north-west and south-west of the country, as well as on the Indian coast
East African plateau 187
ocean south of 4° S. sh., where the mountainous meridional coast delays moist winds from the Indian Ocean. In the rest of the plateau, 750-1000 mm of precipitation falls per year, decreasing in the extreme northeast and in closed depressions to 500 mm or less. Kenya is the driest region of the plateau, with a long rainless period of 7 to 9 months.
For territories located between 5° N. w. and 5° S. sh., is characterized by an equatorial precipitation regime, with two rainy seasons (March-May and November-December), separated by two periods of relative decrease. To the south they merge into one rainy season (from October-November to March-April), followed by a dry period.
The East African Plateau occupies a watershed - a position between the basins of the Atlantic, Indian Oceans and the Mediterranean Sea. In the north-west of the region, the Nile originates, the system of which includes lakes Victoria, Kyoga, Albert and Edward. Lakes Tanganyika and Kivu belong to the Congo river system; Lake Nyasa drains into the Zambezi. In the central part of the plateau there are endorheic lakes (Rudolph, Ruk-va, Baringo, etc.). In terms of size, depth, influence on flow and climate, the lakes of the plateau are comparable to the Great Lakes of North America.
The tectonic fragmentation of the plateau, the diversity of relief and climatic conditions determine the diversity and variety of landscapes. Inland areas are dominated by typical savannas with fairly large tracts of woodlands and shrubs that shed their leaves during the dry season. The vegetation consists of cereals, acacias, mimosas, baobabs, tama-
risks, milkweed, etc. Red-brown soils are developed under typical savannas and open forests on the plains, black tropical soils are developed in poorly drained relief depressions, and young brown tropical soils are found on basic volcanic rocks.
In the arid northeastern regions (Kenya plateau, north of 2°-3° N latitude), desert savannas and thickets of thorny shrubs of xerophytic acacias, leafless for most of the year, are developed on red-brown soils, sometimes turning into semi-desert. Similar and more arid landscapes are characteristic of the deep depressions of the central fault system, where drainless lakes are half-filled with sand, covered with a crust of salts, and surrounded by salt marshes with halophytic vegetation.
The northern part of the coastal lowland off the coast of the Indian Ocean also has sparse, semi-desert vegetation. In the southern part of the lowlands, semi-deserts give way to savannas, red-brown soils give way to red ones; Mixed deciduous-evergreen forests appear along rivers and on the windward slopes of mountains. There are mangroves along the coast.
In heavily moist areas
widespread humid equatorial
forests on red-yellow soils and
mixed deciduous-evergreen-
new ones - on red soils. They are mostly cut down and replaced by secondary formations - wet tall grass savannas. Evergreen and mixed forests are found mainly in the west (Lacustrine Plateau), where they meet the hylaea of the Congo Basin, as well as on the windward moist slopes of the high mountain ranges.
188 Africa. Regional overview
The South African plateau lies on either side of the Southern Tropic.
In the relief and structure of the plateau, a system of internal syneclises and bordering protrusions of the Archean-Proterozoic basement stands out. Syneclises correspond to high accumulative plains filled with alluvial sediments and partially swampy. In the north there is the basin of the upper Zambezi, to the south there is a basin occupied by the vast mainland Okavango delta, and the Makarikari basin periodically flooded with water, and even further south - the Kalahari.
The projections of the foundation bordering the interior of the plateau form a system of basement plateaus and hills, which gradually rise towards the outskirts, reaching a height of 1200-2500 m or more. Their relief is dominated by smooth surfaces of peneplains with separately protruding sections of island mountains. The plateaus are especially wide in the east and south. To the north of the Limpopo River there is the Matabele Plateau, to the south - the High Veldt and Upper Karoo. In the west, the Kaokofeld, Damaraland, Great Namaqualand, etc. plateaus rise. In the north, the ring of uplifts is closed by hills that serve as watersheds between the Zambezi and the Congo.
In the west and northeast, the high plateaus of South Africa are composed of Precambrian crystalline rocks; in the southeast and south, the crystalline basement is lowered and hidden under a thick layer (several thousand meters) of lagoonal sediments of Permo-Triassic age, known as the Karoo formation. In some places, all these rocks were intruded by lavas of the late Paleozoic - early Mesozoic, forming separate massifs (for example, in the southeast the Basuto massif up to 3000 m high).
High plateaus, gradually rising from the interior to the outskirts, end in the east, south and west with the steep Great Escarpment. Its outer slopes are deeply dissected by erosion. The highest part of the Escarpment is the Drakensberg Mountains, whose peak Thabana Ntlenyana (3482 m) is the highest in South Africa.
Between the lower reaches of the Zambezi and Limpopo rivers, at the foot of the Great Escarpment, lies the vast Mozambican plain with a lagoonal coast, which was drained only in the Anthropocene and is composed of a thick series of sedimentary deposits.
The Great Escarpment continues in the extreme south of the mainland, forming the Nuwefeldberge and Rochhefeldberge ranges. The Great Karoo depression, located at their foot, separates the parallel ridges of the Cape mountain system from the South African plateau. Turning north, the Escarpment stretches along the entire western edge of South Africa, ending in the relatively narrow Atlantic Plain. The area of this plain between the Kunene and Orange rivers is called the Namib Desert.
South Africa contains a significant portion of the continent's most important mineral resources. In addition to the large reserves of coal contained in the sediments of the Karoo formation, there are many minerals associated with their origin in the crystalline and volcanic rocks of the platform. These are copper, iron, tin, lead: zinc and zinc ores, gold deposits, distributed throughout the South African plateau, both placer and vein. The Witwatersrand deposit is particularly rich, where gold occurs in strata of pre-Paleozoic conglomerates. South Africa is also home to most of the deposits of African diamonds, which are widespread both in bedrock and in the form of placers.
The South African highlands are an area of high temperatures and relatively poor rainfall, where steppe, semi-desert and desert landscapes predominate. But in some areas, topography and the influence of prevailing air currents change this picture.
The entire eastern edge of South Africa is influenced by the southeast trade wind, bringing humid tropical air from the Indian Ocean, heated over the warm Mozambique Current. In summer, the zone of influence of the trade wind moves far to the south and covers all the plateaus and plains facing the Indian Ocean. A particularly large amount of precipitation falls on the eastern slopes of the mountains: in the lower Zambezi basin - more than 1500 mm, on the slopes of the Drakensberg Mountains - more than 1000 mm. The most frequent and heaviest rains occur from November to April. During the winter months of the southern hemisphere, rainfall decreases sharply as the trade winds move northward and the eastern edge of South Africa is exposed to dry winds blowing from the continent.
The summer maximum precipitation remains in the interior parts of the plateau, but its annual amounts gradually decrease towards the west. Having passed through the outlying mountains, the air of the trade winds within the internal plateaus and basins experiences a descent and does not produce rain. In the Zambezi and Kalahari basins, precipitation falls below 300 mm per year, but nowhere do these amounts drop below 125 mm. In the west of the Kalahari, where a front forms between the Indian and Atlantic trade winds, the amount of precipitation increases to 300-400 mm, and on the Atlantic coast it sharply decreases again.
The driest part of South Africa is the coastal Namib Desert. The Atlantic coast is inaccessible to moist air masses brought from the Indian Ocean, but it is under the constant influence of the eastern periphery of the Atlantic High, enhanced by the powerful cold Benguela Current. This effect is manifested in constant winds from the Atlantic Ocean, bringing moisture-saturated and relatively cold air, which warms up over the surface of the continent, almost completely without releasing the moisture it contains. This part of South Africa is dominated by almost rainless desert conditions, but with moderate temperatures that vary little throughout the year.
South Africa is characterized by frequent and significant annual temperature fluctuations. Almost everywhere, with the exception of the coastal lowlands, the temperature is moderated by a significant absolute height, and in the west there is also the influence of cold currents. Therefore, even on strongly heated plateaus and basins in the summer, the temperature almost never rises above +40°C. In most of the plateau, summer daytime temperatures rarely exceed + 20°C, and in many places they are even lower. The average temperature of the hottest month at the mouth of the Orange River does not rise above +15°C.
The rainfall poverty of much of South Africa is reflected in its water network. There are very few rivers with a permanent flow; only the Zambezi is navigable. All permanent watercourses begin on the outlying plateaus, mainly in the north and east. Their regime depends entirely on rain. Almost all rivers have many waterfalls and rapids.
Apart from the Zambezi, one of the largest rivers in Africa, the largest rivers of the South African highlands are the Orange and Limpopo. Of these, the Limpopo is the deepest, collecting its waters from the Matabele Plateau and the High Veldt. However, even on this river, uneven conditions and rapid rapids impede navigation. The Orange River, flowing into the Atlantic Ocean, is relatively rich in water and very rapids in the upper reaches; in the middle reaches, flowing in arid regions, it becomes very shallow. Rapidly advancing rain floods often turn this river into a turbulent, irresistible torrent. North of the Orange River, not a single significant river flows into the Atlantic Ocean. Only small streams flow into the Indian Ocean from the outlying mountains.
Almost the entire interior drains into basins with salt lakes or swamps. Most of the riverbeds in this area do not have permanent watercourses, and they sometimes remain dry all year round. This indicates climate drying out during the Anthropocene.
The large size of the South African plateau, differences in topography and rainfall create a variety of soil types and vegetation. The flora combines elements that came from other continents of the southern hemisphere, with elements of the tropical flora of the northern hemisphere and the local Cape flora.
On the northern and eastern edges of the plateau, where the most precipitation falls, park forests predominate. Tropical rainforests with lianas and palm trees are distributed mainly along rivers in the form of gallery forests, on the eastern outskirts of the mountain ranges. The plains and high plateaus of the north and east are dominated by sparse forests of boxwood, red beech and cabbage palm on brown-red tropical soils. In some places, forests alternate with savanna, where giant baobabs, acacias and palm trees rise among the dense grasses, as in the northern hemisphere. At an altitude of more than 1000 m, the forests give way to thickets of thorny bushes and a cover of tall grasses; even higher are typical alpine meadows. This change in vegetation is especially pronounced on the slopes of the Drakensberg Mountains.
Most of the plateau is covered with xerophilic vegetation. In the interior, vast areas are occupied by shrubs and dry steppes, which dramatically change their appearance during the wet and dry seasons.
On the gentle slopes of the eastern plateaus, facing inland, there is still quite a lot of rainfall; treeless terrain with a thick cover of tall grasses prevails there. This landscape is called the "veld" in South Africa. The green grass cover of the veld serves as excellent fodder for livestock both in summer and winter. The soils of the veld are favorable for agriculture, and large areas are used for corn crops.
As you move westward, the amount of precipitation decreases and the vegetation takes on an increasingly xerophytic appearance. It consists of various bulbous plants that turn green and bloom only during a short period of rain, low-growing prickly acacias, and numerous types of aloe. The Kalahari has completely barren rocky areas with sparsely growing plants. Wild watermelons are very characteristic of the Kalahari, the vines of which cover large areas. Obviously, all known cultivated types of watermelons originate from here. When there is a great lack of moisture, watermelons with their water reserves save people and animals from thirst.
The vegetation of the Namib Desert is even poorer, where only isolated specimens of Welwitschia are found, anchored on the sand with powerful roots, and low-growing thorny bushes.
The shores of dry lakes and swamps in the Kalahari and upper Zambezi depressions are covered with more moisture-loving vegetation, which serves as a refuge for wild animals.
The South African plateau, with its wide variety of landscapes, has a very rich fauna. In many areas, hunting and fishing are still the main occupation of the local and newcomer population. But with the arrival of Europeans, the number of wild animals decreased noticeably and many of their species almost completely disappeared. The number of herbivores - antelopes, zebras and giraffes - has especially decreased; predators have also been greatly exterminated. Lions, leopards, wild cats and dogs have almost completely disappeared; hyenas and jackals are more common. The number of elephants and large black buffaloes has also greatly decreased, and there are almost no rhinoceroses left.
In the Republic of South Africa, attempts are being made to protect wild animals from complete extermination. The largest national park, Kruger, contains all the animals of the continent, from the largest mammals to birds and reptiles.
“Nature of Africa” - The zebra quagga had stripes only on the neck and face. Lived in the savannas of East Africa. Lived in Morocco, Tunisia, and Algeria until the 18th century. Project "Great Artificial River". Only people conducting research work are allowed here. The unique and only park in East Africa where pink flamingos are protected is Lake Nakuru National Park.
"Africa relief" - Relief and rocks. Relief of individual parts of the continent. Ahaggar Highlands. Low Africa. East African plateau. Water. A t l a s. East African plateau. Tibesti Highlands. Soils. High Atlas The highest point of Toubkal, 4,165 m. Let us repeat: Relief of Africa. Climate. South Africa. Plan for studying the relief of the continent.
“Relief of Africa” - Comparison of mountains by height. Junker V.V. 2. Choose the correct answer: Scheme of the East African faults. In the African language, “Kalimangara” means “shining mountain”. Darfur plateau. A graben is a depressed section of the earth's crust, separated by faults. Crossword. Relief image on the map. 1926 – 1927 East African plateau.
“Plants and Animals of Africa” - Flora and fauna of Africa. Ebony. Marabou. Aloe. Animals and plants of the tropical desert. Velvichia. Leopard. Animals and plants of the savanna. Animals and plants of equatorial forests. Okapi. Baby antelope. Spurge.
“Structure of the African relief” - Nomenclature “Relief”. Geological clock for Africa. Characteristics of high southeast Africa. Features of the modern relief of Africa. Relief of Africa. Repetition. Atlas Mountains. Characteristics of low northwestern Africa. Formation of the relief of Africa. Highlands. Nomenclature “Relief” 1. Atlas Mountains (Tubkal 4165) 2. Ahaggar Highlands.
“Relief of continent Africa” - The relationship between the tectonic structure. Minerals of Africa. Stages of development of the earth's crust. North Africa. Relief of the mainland. Mount Kenya. Relief of individual parts of the continent. Northeast Africa. Gorée Island. Kalahari Plains. What lithospheric plate does Africa lie on? What is called relief.
There are 10 presentations in total
The East African Plateau is located on both sides of the equator, between the Congo Basin in the west and the Indian Ocean in the east, Eastern Sudan, the Ethiopian Highlands, the Somali Peninsula in the north and the lower reaches of the Zambezi in the south and covers the area from 5° N. w. to 17° south w.
The plateau is a mobile, tectonically active part of the African Plate. The greatest rift system and the greatest heights of the continent are concentrated here. It is composed of Precambrian crystalline rocks, among which granites are widespread. The ancient foundation is covered in places by Paleozoic and Mesozoic continental sediments.
The plateau remained an elevated area for a long time. In the Cenozoic, enormous tectonic faults and rifts arose. Rifts are expressed in relief as narrow depressions with steep stepped slopes; along their edges rise high mountain ranges (Rwenzori massif, volcanoes Kilimanjaro, Kenya, Elgon, etc.).
Western fault system runs along the western edge of the plateau and includes deep grabens occupied by the Albert Nile River valley, lakes Albert (Mobutu-Sese-Seko), Edward, Kivu, and Tanganyika. From Lake Tanganyika it stretches through the depression with the endorheic Lake Rukwa, the tectonic basin of Lake Nyasa, the Shire River valley and the lower reaches of the Zambezi. This is one of the most seismic zones of the continent and an arena of modern volcanism.
The grabens of Lakes Albert and Lake Edward are separated by the Rwenzori horst massif, the highest peak in Africa (5119 m) after Kilimanjaro (5895 m) and Kenya (5199 m). The massif is composed of gneisses, crystalline schists and intrusions of basic rocks, has glacial forms of Quaternary and modern glaciation (kars, cirques, trough valleys, terminal moraines), giving an alpine character to the relief of its peaks.
Adjacent to the northern segment of the western fault system from the east is Lake Plateau(Uganda plateau). The plateau has an undulating surface, composed of crystalline rocks and reaches a height of 1000 to 1500 m. The central part of the plateau is occupied by a swampy plain with Lake Kyoga.
Central fault system serves as a continuation of the Ethiopian graben, running in a meridional direction from Lake Rudolf in the north to Lake Nyasa in the south, where it meets the western fault system.
In the northern part of the central faults, within the volcanic plateau of Kenya, volcanic relief is pronounced. The extinct volcanoes Kilimanjaro, Kenya, Elgon and a group of giant craters rise along tectonic cracks.
Between the western and central fault systems, on the one hand, and lakes Victoria and Nyasa, on the other, there is Unyamwezi plateau. It is composed of granites and is very swampy. To the east are the Nyasa and Masai plateaus.
Eastern fault system is represented predominantly by one-sided faults. They limit with ledges from the west a narrow coastal lowland composed of permeable Tertiary sandstones and limestones.
The climate of the East African Plateau is subequatorial, hot, variable-humid, with a clearly defined climatic zone on high mountain ranges. Only in the vicinity of Lake Victoria, on the Lake Plateau, does it approach the equatorial one both in terms of the amount and regime of precipitation, and in the even course of temperatures, which, however, due to the high altitude of the area, are 3-5 °C lower than the average monthly temperatures of the equatorial stripes in the Congo Basin.
Within the plateau, trade winds and equatorial monsoons dominate. During the winter months of the Northern Hemisphere, the northeast trade wind is drawn into a pressure depression over the Kalahari. Passing over the ocean from Southeast Asia to Africa, it is moistened and produces a small amount of precipitation, mainly orographic. In the summer of the Northern Hemisphere, the south trade wind (southeast wind) intensifies; crossing the equator, it takes on the character of a southwest monsoon.
High temperatures are observed only at low altitudes, especially along the Indian Ocean coast. In Dar es Salaam, for example, the average temperature of the warmest month (January) is +28 °C, the coldest month (August) is + 23 °C. It gets cooler with altitude. In the mountains at an altitude of more than 2000 m, the temperature is below 0 ° C, snow falls above 3500 m, and on the highest massifs - Rwenzori, Kilimanjaro and Kenya - there are small glaciers.
The moisture content of different parts of the East African Plateau varies. High mountain ranges receive the greatest amount of precipitation (up to 2000-3000 mm or more). From 1000 mm to 1500 mm of precipitation falls in the north-west and south-west of the country, as well as on the Indian Ocean coast south of 4° S. w. In the rest of the plateau, 750-1000 mm of precipitation falls per year, decreasing in the extreme northeast and in closed depressions to 500 mm or less. Kenya is the driest region of the plateau.
The East African Plateau occupies a watershed position between the basins of the Atlantic, Indian Oceans and the Mediterranean Sea. In the north-west of the region, the Nile originates, the system of which includes lakes Victoria, Kyoga, Albert and Edward. Lakes Tanganyika and Kivu belong to the Congo river system; Lake Nyasa drains into the Zambezi. In the central part of the plateau there are endorheic lakes (Rudolph, Ruk-va, Baringo, etc.).
The tectonic fragmentation of the plateau, the diversity of relief and climatic conditions determine the diversity and variety of landscapes. Inland areas are dominated by typical savannas with fairly large tracts of woodlands and shrubs. The vegetation consists of cereals, acacias, mimosas, baobabs, tamarisks, euphorbias, etc. Red-brown soils are developed under typical savannas and woodlands on the plains, black tropical soils are developed in poorly drained relief depressions, and young brown tropical soils are found on basic volcanic rocks.
In the arid northeastern regions (Kenya Plateau, north of 2°-3° N latitude), desert savannas and thickets of thorny shrubs of xerophytic, leafless acacias are developed on red-brown soils, sometimes turning into semi-desert. Drier landscapes characterize the deep depressions of the central fault system.
The northern part of the coastal lowland off the coast of the Indian Ocean also has sparse, semi-desert vegetation. In the southern part of the lowlands, semi-deserts give way to savannas, red-brown soils give way to red ones; Mixed deciduous-evergreen forests appear along rivers and on the windward slopes of mountains. There are mangroves along the coast. Evergreen and mixed forests are found mainly in the west (Lacustrine Plateau), where they meet the hylaea of the Congo Basin. On the slopes of Kilimanjaro and in other mountains up to an altitude of 2100-2800 m, evergreen equatorial forests and mountain gili with lianas and epiphytes grow. There is a lot of rainfall here. Trees are represented by coniferous and deciduous species. Lots of lichens and mosses. Mountain forests at altitudes of 1100-2000 m have been greatly altered by humans and have given way to park landscapes, where grassy spaces alternate with groves. Above the mountain gils (up to 3100-3900 m) there are thickets of bamboo and tree-like juniper, giving way to mountain tall grass meadows with giant tree-like groundsels (senecio) and lobelias. Starting from an altitude of 4200-4500 m, sparse lichen vegetation grows on rocky placers and cliffs. The peaks of Kilimanjaro, Kenya, Rwenzori from 4800 m are covered with eternal snow and glaciers.
The fauna of the plateau is rich and diverse. Monkeys, elephants, giraffes, rhinoceroses, buffaloes, zebras, antelopes (kudu, eland, etc.) find rich food in savannas, woodlands and forests. Predators include lions and leopards. Hippos, crocodiles, and birds nest in river and lake thickets and reservoirs. The avifauna is richly represented: guinea fowl, marabou, secretary bird, African ostrich, shoebill, etc. Drier places are inhabited by lizards and snakes. The plateau is home to world-famous national parks and reserves. The Kivu National Park (Zaire), which includes the Rwenzori Mountains, protects the landscapes and rich wildlife of forests, savannas, and volcanic areas, including mountain gorillas. The national parks of Kagera in Rwanda, Serengeti, Ngorongoro in Tanzania, etc. are world famous.