Ancient mountains in southeastern Africa. Location of ancient continents and continents, climate conditions and faunistic zoning

Plains prevail on the territory of Africa; mountain ranges are almost absent here. The mainland is located on the ancient African-Arabian platform, which is the remains of the most ancient mountains.

That is why mountain building processes on the mainland are very poorly developed - young mountains grow only in the north of the continent.

Highlands and plateaus of Africa

More than 4/5 of Africa is occupied by plateaus. Lowlands on the mainland are virtually absent. Not only the mainland is located on the African-Arabian platform, but also Madagascar, the Seychelles and the Arabian Peninsula.

The African highlands are located in the southeastern part of the mainland. Average heights here exceed 1000 m. Above sea level. In this region, the African-Arabian platform rises somewhat.

The Ethiopian Highlands are located in the southeast of Africa. This part of the mainland is called High Africa, it is here that the highest peak of the continent is located - Mount Kilimanjaro.

These areas are characterized by frequent earthquakes, which provoke the eruptions of the volcanoes Karisimbi and Cameroon. Highlands are also found in the Sahara Desert, the highest of which are the Tibesti and Ahaggar Highlands.

Mountains of africa

The Cape and Drakensberg Mountains are located on the coast of the Indian Ocean - their height decreases towards the center of the mainland. The Cape Mountains were formed during the Upper Paleozoic.

The region of the Cape Mountains is characterized by a Mediterranean type of climate. The Cape Mountains are a vivid example of the revived mountains that formed on ancient destroyed mountain systems and inherited from them the folded structure that can be traced in modern relief.

The highest peak of the Cape Mountains is Mount Compassberg, whose height reaches 2500 m. In the north of the mainland, as a result of the displacement of the spirit of the lithospheric plates, the young Atlas Mountains were formed.

These mountains are an extension of the young mountains of Europe, which are located in the Gibraltar region. The length of the mountain ranges of the Atlas Mountains is 2500 km: they originate in the north of Morocco and stretch as far as Tunisia.

The highest peak of the Atlas Mountains is Mount Toubkal (4100m). Due to tectonic faults, earthquakes often occur in the Atlas Mountains region.

Lowlands of Africa

Lowlands of Africa occupy only 9% of its territory. The lowest point of the continent is the Assal salt lake, which is located on the territory of the state of Djibouti (Red Sea coast). Lowlands are also common in some countries of Central Africa.

Africa is a part of the world with an area with islands of 30.3 million km 2, this is the second place after Eurasia, 6% of the entire surface of our planet and 20% of the land.

Geographical position

Africa is located in the Northern and Eastern Hemisphere (most of it), a small part in the Southern and Western. Like all large fragments of the ancient mainland of Gondwana, it has massive outlines, large peninsulas and deep bays are absent. The length of the continent from north to south is 8 thousand km, from west to east - 7.5 thousand km. In the north, it is washed by the waters of the Mediterranean Sea, in the northeast by the Red Sea, in the southeast by the Indian Ocean, in the west by the Atlantic Ocean. Africa is separated from Asia by the Suez Canal, and from Europe by the Strait of Gibraltar.

Main geographic characteristics

Africa lies on an ancient platform, which determines its flat surface, which in some places is cut by deep river valleys. On the coast of the mainland there are few lowlands, the north-west is the location of the Atlas Mountains, Northern part, almost completely occupied by the Sahara Desert, - the Ahaggar and Tibetsi highlands, the east - the Ethiopian Highlands, the southeast - the East African Plateau, the extreme south - the Cape and Drakenshi Mountains. The highest point in Africa is Kilimanjaro Volcano (5895 m, Masai Plateau), the lowest is 157 meters below sea level in Lake Assal. The world's largest rift stretches along the Red Sea, in the Ethiopian Highlands and to the mouth of the Zambezi River crust, which is characterized by frequent seismic activity.

Rivers flow through Africa: Congo (Central Africa), Niger (West Africa), Limpopo, Orange, Zambezi (South Africa), as well as one of the deepest and longest rivers in the world - the Nile (6852 km), flowing from the south to north (its origins are on the East African Plateau, and it flows into the Mediterranean Sea, forming a delta). Rivers are rich in water exclusively in the equatorial zone, due to the fallout there a large number precipitation, most of them have a high flow rate, have many rapids and waterfalls. In lithospheric faults filled with water, lakes formed - Nyasa, Tanganyika, the largest freshwater lake in Africa and the second largest lake after Lake Superior (North America) - Victoria (its area is 68.8 thousand km 2, length 337 km, max depth - 83 m), the largest saline closed lake - Chad (its area is 1.35 thousand km 2, located on the southern edge of the greatest desert in the world of the Sahara).

Due to the location of Africa between two tropical zones, it is characterized by high total indicators of solar radiation, which gives the right to call Africa the hottest continent of the Earth (the highest temperature on our planet was recorded in 1922 in El-Azizia (Libya) - + 58 С 0 in the shadow).

On the territory of Africa, such natural zones are distinguished as evergreen equatorial forests (the coast of the Gulf of Guinea, the Congo depression), in the north and south, turning into mixed deciduous-evergreen forests, then there is a natural zone of savannas and woodlands, extending to Sudan, East and South Africa, to Sevres and southern Africa, savannas are replaced by semi-deserts and deserts (Sahara, Kalahari. Namib). In the southeastern part of Africa there is a small zone of mixed coniferous-deciduous forests, on the slopes of the Atlas Mountains - a zone of rigid-leaved evergreen forests and shrubs. Natural zones of mountains and plateaus are subject to the laws of altitudinal zonation.

African countries

The territory of Africa is divided between 62 countries, 54 - independent, sovereign states, 10 dependent territories belonging to Spain, Portugal, Great Britain and France, the rest - unrecognized, self-proclaimed states - Galmudug, Puntland, Somaliland, Saharan Arab Democratic Republic(SADR). For a long time, the countries of Asia were foreign colonies of various European states and gained independence only by the middle of the last century. Depending on the geographic location Africa is divided into five regions such as North, Central, West, East and South Africa.

List of countries in Africa

Nature

Mountains and plains of Africa

Most of the African continent is plain. There are mountain systems, highlands and plateaus. They are presented:

• The Atlas Mountains in the northwestern part of the continent;
• the highlands of Tibesti and Ahaggar in the Sahara desert;
• The Ethiopian Highlands in the eastern part of the mainland;
• Drakensberg mountains in the south.

The highest point in the country is Kilimanjaro Volcano, 5,895 m high, belonging to the East African Plateau in the southeastern part of the mainland ...

Deserts and savannahs

The largest desert zone of the African continent is located in the northern part. This is the Sahara Desert. On the southwestern side of the continent is another smaller desert, the Namib, and from it inland to the east is the Kalahari Desert.

The savannah territory occupies the main part of Central Africa. In area, it is much larger than the northern and southern parts of the mainland. The territory is characterized by the presence of pastures typical of savannahs, low shrubs and trees. The height of herbaceous vegetation varies depending on the amount of precipitation. These can be practically desert savannas or tall-grass, with a grass cover from 1 to 5 m in height ...

The rivers

The longest river in the world, the Nile, is located on the territory of the African continent. The direction of its flow is from south to north.

In the list of large water systems of the mainland, Limpopo, Zambezi and the Orange River, as well as the Congo, flowing through the territory of Central Africa.

On the Zambezi River, there is the famous Victoria Falls, 120 meters high and 1,800 meters wide ...

Lakes

The list of large lakes on the African continent includes Lake Victoria, which is the world's second largest freshwater body of water. Its depth reaches 80 m, and its area is 68,000 square kilometers. There are two more large lakes of the continent: Tanganyika and Nyasa. They are located in the fractures of lithospheric plates.

There is Lake Chad on the territory of Africa, which is one of the world's largest closed relict lakes that have no connection with the world's oceans ...

Seas and oceans

The African continent is washed by the waters of two oceans at once: the Indian and the Atlantic. Also on its shores are the Red and Mediterranean Seas. From the side Atlantic Ocean in the southwestern part of the water they form the deep Gulf of Guinea.

Despite the location of the African continent, coastal waters are cool. This is influenced by the cold currents of the Atlantic Ocean: the Canary in the north and the Bengal in the southwest. The currents from the Indian Ocean are warm. The largest are Mozambique, in the northern waters, and Igolnoye, in the southern ...

Forests of africa

Forests from the entire territory of the African continent make up a little more than a quarter. There are subtropical forests growing on the slopes of the Atlas Mountains and the valleys of the ridge. Here you can find a stone oak, pistachio, strawberry tree, etc. High in the mountains, conifers grow, represented by Aleppo pine, Atlas cedar, juniper and other types of trees.

Closer to the coast there are forests of cork oak, in the tropical region there are evergreen equatorial plants, for example, mahogany, sandalwood, ebony, etc.

Nature, plants and animals of Africa

The vegetation of the equatorial forests is diverse, about 1000 species grow here various types trees: ficus, ceiba, wine tree, oil palm, wine palm, banana palm, tree ferns, sandalwood, mahogany, rubber trees, Liberian coffee tree, etc. It is home to many species of animals, rodents, birds and insects that live right in the trees. Live on earth: bush-eared pigs, leopards, African deer - a relative of the okapi giraffe, large apes - gorillas ...

Savannahs occupy 40% of Africa's territory, which are huge steppe areas covered with forbs, low, thorny shrubs, milkweed, and free standing trees (treelike acacias, baobabs).

There is the largest concentration of such large animals as: rhino, giraffe, elephant, hippo, zebra, buffalo, hyena, lion, leopard, cheetah, jackal, crocodile, hyena dog. The most numerous animals of the savannah are such herbivores as: bubal (antelope family), giraffe, impala or black-heeled antelope, different kinds gazelles (Thomson, Grant), blue wildebeest, in some places there are still rare springbok antelopes.

The vegetation of deserts and semi-deserts is characterized by poverty and unpretentiousness, these are small thorny shrubs, separately growing bunches of grasses. The oases are home to a unique date palm Erg Chebbi, as well as drought and salt tolerant plants. In the Namib Desert, unique plants grow velvichia and bun, the fruits of which feed on porcupines, elephants and other animals of the desert.

Of the animals, various species of antelopes and gazelles live here, adapted to the hot climate and able to travel great distances in search of food, there are many species of rodents, snakes, and turtles. Lizards. Among mammals: spotted hyena, common jackal, maned ram, Cape hare, Ethiopian hedgehog, Dorcas gazelle, saber-horned antelope, Anubis baboon, wild Nubian donkey, cheetah, jackal, fox, mouflon, there are constantly living and migratory birds.

Climatic conditions

Seasons, weather and climate of African countries

The central part of Africa, through which the equator line passes, is in an area of ​​low pressure and receives sufficient moisture, the territories north and south of the equator are located in the subequatorial climatic zone, this is a zone of seasonal (monsoon) moisture and arid desert climate. The extreme north and south are in the subtropical climatic zone, the south receives precipitation brought by air masses from the Indian Ocean, the Kalahari Desert is located here, the north receives the minimum amount of precipitation due to the formation of the region high pressure and the peculiarities of the movement of trade winds, the largest desert in the world is the Sahara, where the amount of precipitation is minimal, in some areas it does not fall at all ...

Resources

Natural resources of Africa

By reserves water resources Africa is considered one of the poorest continents in the world. The average annual volume of water is only enough to meet the priority needs, but this does not apply to all regions.

Land resources are represented by areas of significant area with fertile lands. Only 20% of all possible land is cultivated. The reason for this is the lack of adequate water volume, soil erosion, etc.

The forests of Africa are a source of timber, including valuable species. The countries in which they grow, raw materials are sent for export. Resources are being used unwisely and ecosystems are gradually being destroyed.

There are mineral deposits in the bowels of Africa. Among those exported: gold, diamonds, uranium, phosphorus, manganese ores. There are significant reserves of oil and natural gas.

Energy-intensive resources are widely represented on the continent, but they are not used due to the lack of proper investment ...

Among the developed industrial spheres of the countries of the African continent, one can note:

• the mining industry, which sends mineral raw materials and fuels for export;
• the oil refining industry, distributed mainly in South Africa and North Africa;
• chemical industry specializing in the production of mineral fertilizers;
• as well as the metallurgical and engineering industries.

Main products Agriculture are cocoa beans, coffee, corn, rice and wheat. Oil palm is grown in tropical regions of Africa.

Fishing is developed insignificantly and constitutes only 1 - 2% of the total volume of agriculture. Livestock indicators are also not high and the reason for this is the infection of livestock with tsetse flies ...

The culture

The peoples of Africa: culture and traditions

About 8000 peoples live on the territory of 62 African countries and ethnic groups, which in total is about 1.1 billion people. Africa is considered the cradle and ancestral home of human civilization, it was here that the remains of ancient primates (hominids) were found, which, according to scientists, are considered the ancestors of humans.

Most of the peoples in Africa can number as many as several thousand people, and several hundred, living in one or two villages. 90% of the population are representatives of 120 peoples, their number is more than 1 million people, 2/3 of them are peoples with a population of more than 5 million people, 1/3 are peoples with a population of more than 10 million people (this is 50% of the total population of Africa) are Arabs , Hausa, Fulbe, Yoruba, Igbo, Amhara, Oromo, Rwanda, Malagasy, Zulus ...

There are two historical and ethnographic provinces: North African (predominance of the Indo-European race) and Tropical-African (the majority of the population is a Negroid race), it is divided into such areas as:

• West africa... Peoples speaking the languages ​​Mande (Susu, Maninka, Mende, Vai), Chad (Hausa), Nilo-Saharan (Songhai, Kanuri, Tubu, Zagawa, Mawa, etc.), Niger-Congolese languages ​​(Yoruba, Igbo, Bini, nupe, gbari, igala and idoma, ibibio, efik, kambari, birom and jukun, etc.);
• Equatorial africa... Inhabited by Buanto-speaking peoples: Douala, Fang, Bubi (Fernandians), Mpongwe, Teke, Mboshi, Ngala, Como, Mongo, Tetela, Cuba, Congo, Ambundu, Ovimbundu, Chokwe, Luena, Tonga, Pygmies, etc .;
• South Africa... Rebellious peoples, and speaking the Khoisan languages: Bushmen and Hottentots;
• East africa... Bantu, Nilot and Sudanese groups;
• Northeast africa... Peoples speaking Ethiosemitic (Amhara, Tiger, Tiger.), Kushite (Oromo, Somalis, Sidamo, Agau, Afar, Konso, etc.) and Omotic languages ​​(Ometo, Gimirra, etc.);
• Madagascar... Malagasy and Creoles.

In the North African province, the main peoples are the Arabs and Berbers, belonging to the southern European minor race, mainly professing Sunni Islam. There is also an ethno-religious group of Copts who are direct descendants of the Ancient Egyptians, they are Christians-Monophysites.

In the Cambrian period (570 - 500 million years ago), the distribution of land over the Earth's surface was different than at present.

There was a continent in the place of North America and Greenland Laurence... South of Laurentia stretched Brazilian mainland. African the mainland included Africa, Madagascar and Arabia.

To the north of it was located Russian continent corresponding to the Russian platform within the boundaries of the Danube delta, Dniester, Vistula, the Norwegian Sea, the Barents Sea, the Pechora, Ufa, Belaya rivers, the north of the Caspian Sea, the Volga delta, the north of the Black Sea. The center of the platform is the city of Vladimir between the Oka and Volga rivers. On the Russian platform, Cambrian deposits are distributed almost everywhere in its northern part, and are also known in the western parts of modern Belarus and Ukraine.

To the east of the Russian mainland was located Siberian mainland - Angarida, including the Siberian platform and adjacent mountain structures. In the place of modern China, there was Chinese mainland, south of it - Australian mainland covering territory modern India and Western Australia.

At the beginning of the Paleozoic (Ordovician period, 500 - 440 million years ago) in the Northern Hemisphere from the ancient platforms - Russian, Siberian, Chinese and North American - a single continent was formed Laurasia.

Hindustan (Madagascar island, Hindustan peninsula, south of the Himalayas), African (without the Atlas Mountains), South American (east of the Andes), Antarctic platforms, as well as Arabia and Australia (west of the mountain ranges of its eastern part) entered the southern mainland - Gondwana .

Laurasia was separated from Gondwana by the sea (geosyncline) Tethys(Central Mediterranean, Mesogea), held in Mesozoic era in the Alpine folding zone: in Europe - the Alps, Pyrenees, Andalusian mountains, Apennines, Carpathians, Dinaric mountains, Stara Planina, Crimean mountains, Caucasus mountains; in North Africa - the northern part of the Atlas Mountains; in Asia - the Pontic Mountains and Taurus, the Turkmen-Khorasan Mountains, Elbrus and Zagros, the Suleiman Mountains, the Himalayas, folded chains of Burma, Indonesia, Kamchatka, the Japanese and Philippine Islands; in North America - fold ridges of the Pacific coast of Alaska and California; in South America - the Andes; archipelagos flanking Australia from the east, including islands New Guinea and New Zealand. The territory covered by alpine folding retains high tectonic activity in the modern era, which is expressed in an intensely dissected relief, high seismicity and continuing in many places volcanic activity... The relics of Pratetis are the modern Mediterranean, Black and Caspian Seas.

Laurasia existed until the middle of the Mesozoic, and its changes consisted in the loss of the territories of North America and the subsequent reformation of Laurasia into Eurasia.

The skeleton of modern Eurasia spliced ​​from fragments of several ancient continents. In the center is the Russian continent. In the northwest, it is adjoined by the eastern part of the former Laurentia, which, after the Cenozoic subsidence in the Atlantic Ocean region, separated from North America and formed the European bulge of Eurasia, located west of the Russian platform. In the northeast - Angarida, which in the Late Paleozoic was articulated with the Russian continent by the folded structure of the Urals. In the south, the northeastern parts of the disintegrated Gondwana (Arabian and Indian platforms) joined Eurasia.

The collapse of Gondwana began in the Mesozoic, Gondwana was literally pulled apart piece by piece. By the end of the Cretaceous - the beginning of the Paleogene periods, the modern post-Gondwana continents and their parts - South America, Africa (without the Atlas Mountains), Arabia, Australia, Antarctica - were isolated.

Rice. 3.9.1.1. Tectonics.

The ancient East European platform includes two basement protrusions on the surface - the Baltic Shield and the Ukrainian crystalline massif - and an extensive Russian plate where the foundation is submerged and covered by a sedimentary cover. The Archean (the most ancient geological era, distinguished in the geochronology of the Earth - the beginning of 3.500 Ma - the end of 2.500 - 2.700 Ma ago) and subsequent Lower and Middle Proterozoic strata take part in the structure of the basement. Archean rocks form numerous massifs. The depth of the basement on the Russian plate varies from several hundred meters (on uplifts) to several thousand meters (in depressions). The largest uplifts are the Voronezh, Belorusskaya and Volga-Ural anteclises. Among the depressions, the Moscow, Baltic, Caspian syneclises stand out. The rocks filling the syneclises are from the Vendian to the Cenozoic and form the upper layer of the structures of the Russian Plate. The largest syneclise, the Moscow one, separates the basement protrusion of the Baltic Shield in the north from the Voronezh and Volga-Ural anteclises in the south and southeast. In its axial part, Triassic and Jurassic rocks are developed, on the wings - Permian and Carboniferous. The foundation in its central part is submerged to a depth of 3-4 km.

The Siberian platform has an ancient, predominantly Archean basement. The Siberian platform, in contrast to the East European, at the end of the Proterozoic and the beginning of the Paleozoic was an area of ​​general subsidence and almost universal accumulation of marine sediments. In the second half of the Paleozoic, in the Mesozoic and Cenozoic, it was relatively uplifted and mainly continental deposits accumulated on it. The Siberian platform is distinguished by a high degree of tectonic activity.

The Mediterranean belt is located southwest and south of the East European Platform. The outer zone of the belt (the Scythian plate, the southern part of the Turan plate, the Tajik depression and the Northern Pamir) is a young platform. The Tajik depression and the Northern Pamir in the Neogene - Anthropogene were enveloped in orogeny, as a result of which the Mesozoic and Cenozoic deposits of the platform cover were crumpled into folds here. The Scythian plate, which includes the plain territories of the Crimea and the Ciscaucasia, has a basement, which includes blocks of Upper Proterozoic rocks. The platform cover ubiquitously includes Cretaceous to Anthropogenic deposits. The southern part of the Turan plate has a basement consisting of a number of Precambrian massifs - Central Karakum, Kara-Bogaz, North-Afghan, etc. The cover of the plate as a whole is formed by a series of deposits from the Jurassic to the Anthropogen. The most powerful cover is developed in the southeast in the Murghab and Amu Darya depressions.

The inner zone of the Mediterranean belt (Carpathians, Mountainous Crimea, Caucasus, Kopetdag, Middle and Southern Pamir) is distinguished by the fact that the Mesozoic and Cenozoic deposits in it are represented by the geosynclinal type of formations.

The ancient Archean platforms Russian and Siberian are stable throughout the entire period of existence, starting from the earliest geological time. This creates confident conditions for the existence of various forms of life, and also creates conditions for them for long-term progressive formation and development, not interrupted by geological cataclysms. Under such conditions, organisms developing within ancient platforms acquire a noticeable advantage over others developing in young and tectonically active areas of the earth's crust.

Naturally, evolution gives preference to more stable conditions of existence.

Climatic data on the state of the Earth at that historical time also reveal to us additional possibilities for the knowledge that interests us.

In the Terminal Riphean (680 - 570 million years ago), large areas of Europe and North America were covered by the extensive Lapland glaciation. Glacial deposits of this age are known in the Urals, in the Tien Shan, on the Russian platform (Belarus), in Scandinavia (Norway), in Greenland and the Rocky Mountains.

In the Ordovician period (500 - 440 million years ago) Australia was located near the South Pole, and northwest Africa - in the area of ​​the pole itself, which is confirmed by the signs of widespread glaciation imprinted in the Ordovician rocks of Africa.

In the Devonian period (from 410 million to 350 million years ago), the equator was located at an angle of 55 - 65 ° to the modern and passed approximately through the Caucasus, the Russian platform and southern Scandinavia. The North Pole was in the Pacific Ocean within 0 - 30 ° north latitude and 120 - 150 ° east longitude (in the region of Japan) .

Therefore, on the Russian platform, the climate was near-equatorial - dry and hot, distinguished by a wide variety of the organic world. Part of the territory of Siberia was occupied by seas, the water temperature of which did not go below 25 ° C. The tropical (humid) belt, at different times of the Devonian period, extended from the modern West Siberian Plain in the north to the southwestern edge of the Russian platform. Based on the paleomagnetic study of rocks, it has been established that throughout most of the Paleozoic and North America was located in the equatorial zone. Fossil organisms and widespread limestones of this time testify to the dominance of warm shallow seas in the Ordovician.

On the contrary, in the territory of Gondwana, the climate was polar. In South Africa (in the Cape Mountains), in the Table Mountain Formation, in the Congo Basin and in the southern part of Brazil, there are glacial formations (tillites) - witnesses of a cold circumpolar climate. Extensive glaciation developed in the Proterozoic and Upper Carboniferous. In South Australia, China, Norway, South Africa, southern Europe, in South America, signs of Ordovician glaciation were found within this belt. Traces of Upper Carboniferous glaciation are known in Central and South Africa, southern South America, India and Australia. Glaciations were established in the Lower Proterozoic of North America, in the Upper Riphean (Riphean - 1650 - 570 Ma) of Africa and Australia, in the Vendian (680 - 570 Ma) of Europe, Asia and North America, in the Ordovician of Africa, at the end of the Carboniferous and early Permian on the mainland of Gondwana. Organic world this belt was distinguished by the impoverishment of its composition. In the Carboniferous and Permian periods, a peculiar flora of the temperate and cold zone developed on the mainland of Gondwana, which was characterized by an abundance of glossopteris and horsetails.

In the Devonian, the northern (arid - arid) belt covered Angarida (North Asia) and folded structures adjacent to it from the south and east dominated the continents: Angara, Kazakh, Baltic and North American.

In Colorado (part of the former Lawrence), fragments of the most primitive vertebrates - jawless (ostrocoderms) - were found in the Ordovician sandstones.

After the end of the cycle, geosynclinal development can be repeated, but always some part of the geosynclinal areas at the end of the next cycle turns into a young platform. In this regard, during geological history, the area occupied by geosynclines (seas) decreased, while the area of ​​platforms increased. It is the geosynclinal systems that were the site of the formation and further growth of the continental crust with its granite layer.

The periodic nature of vertical movements during a tectonic cycle (predominantly subsidence at the beginning and predominantly uplift at the end of the cycle) each time led to corresponding changes in the surface topography, to a change in transgressions and regressions of the sea. The same periodic movements influenced the nature of the deposited sedimentary rocks, as well as the climate, which experienced periodic changes. Already in the Precambrian, warm epochs were interrupted by glacial ones. In the Paleozoic glaciation, at times, Brazil, South Africa, India and Australia were covered. The last glaciation (in the Northern Hemisphere) was in the Anthropogen.

* * *

The position of the continents considered above is confirmed by the data of faunistic zoning, according to which the land of the Earth is divided into four faunistic kingdoms: Arktogea, Paleogea, Neogea, Notogea. Antarctic land, inhabited mainly by marine animals, is not included in any of the kingdoms.

Arctogea (" northern land») With the center of grouping on the Russian platform also includes the Holarctic, Indo-Malay, Ethiopian regions and occupies Eurasia (excluding Hindustan and Indochina), North America, North Africa (including the Sahara). The fauna of Akrtogea is characterized by a common origin. Arktogea is inhabited by only placental mammals.

Neogea (" new earth”, Later in time, formed from the decay products of Gondwana) occupies South, Central America from Baja California and the southern part of the Mexican Highlands in the north to 40 ° S latitude. in the south and the islands adjacent to Central America. Placentals are widespread.

Notogea ("southern land") occupies Australia, New Zealand and the islands of Oceania. Prolonged isolation of Notogea led to the formation of a fauna rich in endemics (isolated species). The number of placental mammals is relatively small: mice, bats, canines.

Paleogea occupies mainly tropical regions of the Eastern Hemisphere. The Paleogea is characterized by groups of animals of the ancient fauna of Gondwana - its Brazilian-African continent: ostriches, lungfish, turtles, as well as proboscis, great apes, carnivores, etc.

The above-mentioned fauna distribution draws our attention to a special concentration of placental mammals - within the Arktogea with the center on the Russian Plain. The first placentals are known from the Early Cretaceous (Cretaceous - 135 - 65 million years ago), the deposits of which occupy vast areas on the Russian Platform.

Meanwhile, placental mammals are, firstly, viviparous, and secondly, they are characterized by the highest organization and ecological and morphological diversity - the brain has highly developed cerebral hemispheres, which are connected by the corpus callosum; embryonic development proceeds with the formation of the placenta.

Man belongs to the placentals. The predominance of placentals on the territory of Arktogea gives us reliable grounds for establishing this particular area as the most likely ancestral home of humans.


a source; http://www.organizmica.org/archive/307/rp3.shtml#9

Legends about the disappeared lands

The geological time scale, in which the relief and outlines of the continents change, for a long time was not accessible to human understanding, therefore, the ideas about once existed, but disappeared lands were perceived in the context of mythological stories about fictional countries. Relief changes, such as catastrophic floods, have been experienced by a few generations, and over time, information about them has been intertwined with mythology. So, the most famous of the ancient legends about the disappeared land - Atlantis - already by the time of Plato was perceived as a legend. Modern researchers believe that this myth could have preserved the impressions of the Santorini eruption (nine centuries before Plato), or even of the cataclysms of the beginning of the Holocene (just nine millennia, as indicated in the Platonic text), when vast territories were quickly drained and flooded ... Echoes of such events can be found in flood myths widespread among various peoples.

Formation of scientific paleogeography (XVII-XX centuries)

The widespread dissemination of geological knowledge at the end of the 19th century led to their penetration into a number of neo-mystical teachings, which popularized the idea of ​​now-defunct continents, placing on them the imaginary civilizations of the past, which, in their opinion, were the primary source of human culture. Thus, the occultists placed Atlantis in the Atlantic Ocean, Lemuria in the Indian Ocean, Arctida-Hyperborea in the Arctic Ocean, and the Mu (Pacifida) continent in the Pacific Ocean. Maps of these imaginary ancient continents (mostly located on the site of oceans, but including some territories of modern land) were published, obtained by the spiritual method. By that time, the relief of the ocean floor was becoming known, and the oceanic ridges were naively taken by these authors for the mountains of ancient continents that had sunk to the bottom, and the deep-sea trenches for the channels of ancient rivers. However, these assumptions were in line with the scientific hypotheses of that time. Even F. Engels wrote about the probable "origin of man from a monkey that lived on the continent, which sank to the bottom of the Indian Ocean."

In 1912, Alfred Wegener proposed a theory of continental drift, according to which modern continents are fragments of the once existing supercontinent Pangea - Pangea became the first scientific paleogeographic hypothesis. However, in the first decades, the theory was generally rejected by the scientific community due to the lack of a satisfactory explanation for the mechanism of plate movement. In the USSR, the ideas of mobilism were also considered "insufficiently Marxist" and practically not considered until the final formation of the theory of tectonic plates in the 1970s.

Middle Proterozoic continents (1.6 - 1 billion years ago)

During the first half of the Mesoproterozoic, Colombia changed its shape and location, mainly remaining in the equatorial zone, that is, with one half being predominantly in the northern hemisphere (the main part of this part was the Arctic paleomaterial, which included the North American, Siberian and Baltic cratons; the blocks that make up today Australia and Antarctica), and the second half - in the southern (the basis of this part was the Atlantic paleomaterial, which consisted of the present-day South American and African cratons).

Cambrian period

600-500 million years ago, the distribution of land over the Earth's surface was different than at present.

To the east of the Russian mainland was located Siberian continent- Angarida, including the Siberian platform and adjacent mountain structures. The territory of China was divided into two independently evolved blocks: the North China and South China continents, separated by a wide (up to 700 km) ocean.

Approximately at the latitude of Pannotia, the Australian-Antarctic continent was located.

Ordovician period

Laurasia was separated from Gondwana by the Tethys ocean (Central Mediterranean, Mesogeia), which took place in the Mesozoic era along the Alpine folding zone: in Europe - the Alps, Pyrenees, Andalusian mountains, Apennines, Carpathians, Dinaric mountains, Stara Planina, Crimean mountains, Caucasus mountains; in North Africa - the northern part of the Atlas Mountains; in Asia - the Pontic Mountains and Taurus, the Turkmen-Khorasan Mountains, Elbrus and Zagros, the Suleiman Mountains, the Himalayas, folded chains of Burma, Indonesia, Kamchatka, the Japanese and Philippine Islands; in North America - fold ridges of the Pacific coast of Alaska and California; in South America - the Andes; archipelagos flanking Australia to the east, including the islands of New Guinea and New Zealand. The territory covered by the Alpine folding retains high tectonic activity in the modern era, which is expressed in an intensely dissected relief, high seismicity and continuing volcanic activity in many places. The relics of Pratetis are the modern Mediterranean, Black and Caspian Seas.

Laurasia existed until the middle of the Mesozoic, and its changes consisted in the loss of the territories of North America and the subsequent reformation of Laurasia into Eurasia.

The island of modern Eurasia is spliced ​​from fragments of several ancient continents. In the center is the Russian continent. In the northwest, it is adjoined by the eastern part of the former Laurentia, which, after the Cenozoic subsidence in the Atlantic Ocean, separated from North America and formed the European bulge of Eurasia, located west of the Russian platform. In the northeast - Angarida, which in the Late Paleozoic was articulated with the Russian continent by the folded structure of the Urals. In the south, the northeastern parts of the disintegrated Gondwana (Arabian and Indian platforms) joined Eurasia.

The collapse of Gondwana began in the Mesozoic, Gondwana was literally pulled apart piece by piece. By the end of the Cretaceous - the beginning of the Paleogene periods, the modern post-Gondwana continents and their parts - South America, Africa (without the Atlas Mountains), Arabia, Australia, Antarctica - were isolated.

Climate

In the Terminal Riphean (680-570 Ma ago), large areas of Europe and North America were covered by the extensive Lapland glaciation. Glacial deposits of this age are known in the Urals, in the Tien Shan, on the Russian platform (Belarus), in Scandinavia (Norway), in Greenland and the Rocky Mountains.

In the Ordovician period (500-440 million years ago) Australia was located near the South Pole, and northwestern Africa - in the area of ​​the pole itself, which is confirmed by the signs of widespread glaciation imprinted in the Ordovician rocks of Africa.

Therefore, on the Russian platform, the climate was near-equatorial - dry and hot, distinguished by a wide variety of the organic world. Part of the territory of Siberia was occupied by seas, the water temperature of which did not go below 25 ° C. The tropical (humid) belt, at different times of the Devonian period, extended from the modern West Siberian Plain in the north to the southwestern edge of the Russian platform. Based on the paleomagnetic study of rocks, it has been established that throughout most of the Paleozoic and North America was located in the equatorial zone. Fossil organisms and widespread limestones of this time testify to the dominance of warm shallow seas in the Ordovician.

On the contrary, in the territory of Gondwana, the climate was polar. In South Africa (in the Cape Mountains), in the Table Mountain Formation, in the Congo Basin and in the southern part of Brazil, there are glacial formations (tillites) - witnesses of a cold circumpolar climate. Extensive glaciation developed in the Proterozoic and Upper Carboniferous. In South Australia, China, Norway, South Africa, southern Europe, in South America, signs of Ordovician glaciation were found within this belt. Traces of Upper Carboniferous glaciation are known in Central and South Africa, southern South America, India and Australia. Glaciations were established in the Lower Proterozoic of North America, in the Upper Riphean (Riphean - 1650-570 Ma) of Africa and Australia, in the Vendian (680-570 Ma) of Europe, Asia and North America, in the Ordovician of Africa, in the late Carboniferous and early Permian on the mainland of Gondwana. The organic world of this belt was distinguished by its poor composition. In the Carboniferous and Permian periods, a peculiar flora of the temperate and cold zone developed on the mainland of Gondwana, which was characterized by an abundance of glossopteris and horsetails.

In the Devonian, the northern (arid - arid) belt covered Angarida (North Asia) and folded structures adjacent to it from the south and east dominated the continents: Angara, Kazakh, Baltic and North American.

In Colorado (part of the former Laurentia), fragments of the most primitive vertebrates - jawless (ostrocoderms) - were found in the Ordovician sandstones.

After the end of the cycle, geosynclinal development can be repeated, but always some part of the geosynclinal areas at the end of the next cycle turns into a young platform. In this regard, during geological history, the area occupied by geosynclines (seas) decreased, while the area of ​​platforms increased. It is the geosynclinal systems that were the site of the formation and further growth of the continental crust with its granite layer.

The periodic nature of vertical movements during a tectonic cycle (predominantly subsidence at the beginning and predominantly uplift at the end of the cycle) each time led to corresponding changes in the surface topography, to a change in transgressions and regressions of the sea. The same periodic movements influenced the nature of the deposited sedimentary rocks, as well as the climate, which experienced periodic changes. Already in the Precambrian, warm epochs were interrupted by glacial ones. In the Paleozoic glaciation, at times, Brazil, South Africa, India and Australia were covered. The last glaciation (in the Northern Hemisphere) was in the Anthropogen.

Fauna

The tradition of faunistic zoning, according to which the land of the Earth is divided into four faunistic kingdoms: Arktogea, Paleogea, Neogea, Notogea, finds a paleontological explanation in understanding the migrations of species along the Mesozoic-Cenozoic continents.