Show atlas mountains on the map. The Atlas Mountains are a country of Berber barbarians. Trip to Africa! Trekking in Morocco “High Atlas Mountains and climbing Toubkal”
Between this plateau and the great desert. The Tell Mountains consist of separate groups, sometimes very sharply demarcated from each other by large valleys or vast plains; There are 11 such groups in the direction from W to E: the Ujda Gadada mountain range, between the Muluya and Tafna rivers, with the peak of Jebel Fural (1400 m); Thessala ridge (1022 m), between pp. Tafna and Sig; Tlemcen Mountains, south of the previous ones, between the Moroccan border and Upper Sig, Durdus mons ancient, with the peak of Tumzait (1834 m); horn Saida chain, between the river. Sig and Mina; Jebel Vancherich group (2000 m), between Mina and Sheliff; The Algerian mountain range between Sheliff and the seashore, in the east to the Isser River, with Tagelza (1731 m) and the fertile plain of Metidje at an altitude of 1000-1640 m; Jergera (2317 m), between Isser and Oued Sagele; the southern chain of Dira-Wannuga to the south of Jergera with Dira (1810 m); Setif chain between Oued Sagel and the Constantine River, with Babor (1995 m); Numidian Mountains, between the Constantine River and Oued Sebus in the south to the Sbah Plain, with Jebel Bou Ghareb (1316 m); African mountain range with Serdch el-Ouda (1370), stretching between Medjerda and the seashore to Tunisia. To the south of these coastal chains, almost parallel to them, from Cape Good to the southwest. and W. a number of other mountain ranges stretch to 13° 20" east longitude, then continuing to south side valley of Susa.
The space between both chains is filled with a plateau of chotts, or salt marshes, rising approximately 1000 m, which are located one after the other for more than 900 km and testify to a former connection with the sea (towards the east), like the more southern large chotts to the west. from the Gulf of Gabes, or Lesser Syrt. This plateau provides magnificent pastures for numerous herds of sheep and camels; in the oases there are villages of the shepherd population. The Sahara Mountains represent more connections among themselves; they form a series of narrow chains parallel to each other, occupying an average width of 150 km. In the middle and east. parts of individual chains reach significant heights and received special names; so, for example, Jebel Amur with its highest point El Gada (1657 m), rising to 1937 m Kzel with a wooded peak, two hours from Geriville, and Jebel Aures, which the ancients bore the name Aurasius mons, with the peaks of Shelikha (2398 m) and Mhammel (2306 m), the highest point in Algeria, covered with snow for 4 months of the year. The eastern spurs of A. in Tunisia serve mainly in the north. coast of the mentioned African mountain range, to the south - Jebel Um Debben, Jebel Shambi and Jebel Mehila (1445 m) adjacent to Aures and the mountain range stretching from Cape Good to the southwest with Jebel Barku and Jebel Silk. In addition, Tunisia is filled with many more small isolated hills.
In the Tel Atlas Mountains.
In Morocco, A. forms a continuous mountain range, called Idrar-Nderen among the Amasirgs, and Idrassen or Jebel Drann among the Kabyles, the height of which, according to Hooker, extends to 3960 m. This ridge divides the country into two parts, one of which has the descent to the N., the other to the S., since the Chott plateau does not extend further into Morocco. Here Rolfs found a passage between Fetz and the Tafilet oasis (2085 m), and Ball discovered the Tagerut Pass (3400 m) near Jebel Tezza (3500 m) and Miltzin (3476 m). The highest point of the main chain running from Cape Jira, or Aferni, to the northeast, seems to be Jebel Ayachin, rising to 4000 m. Parallel to A., separated from it by a large longitudinal valley, Susa stretches, starting from Jebel Autus and reaching Cape Nun, double chain Anti-Atlas, reaching 1157 m in height near Isgeder. On both sides of these chains lie vast, often interrupted plains, on the other side of which rise isolated mountain groups, such as, for example, on the north - the Reef (Errif, that is, the coastal chain) with Jebel Anna (2200 m), and on South - less significant heights of the Moroccan Sahara. Crystalline rocks appear only in the southern and northern regions. side A., in numerous coastal points of the Mediterranean Sea and in individual elliptical masses inland. In general, the geological composition of the Atlas Mountains is formed by: Silurian and Devonian transitional deposits, dolomites of an uncertain era, Jurassic Cretaceous formation, nummilite rocks and later deposits of the Tertiary period. The mineral products, as yet little discovered, consist chiefly of copper, iron and lead, rock salt, lime and marble. For more high peaks Mountain snow lies for a significant part of the year, but on Miltzin it completely melts only once in 20 years; There are no glaciers at all. The northern slope is often covered with snow for several weeks in winter. - Initially, the population of the mountains, who in all likelihood ruled the country even before the invasion of the Vandals and Arabs, were Berbers, who also inhabit the West. Sugar. In the West A. they are called Shillukhi, live in houses, cultivate fertile valleys and successfully engage in crafts; to the east they are called parts Masigami, live in tents and caves, and are mainly engaged in raising livestock. Their adverbs are quite different from each other.
The article reproduces material from the Great Encyclopedic Dictionary of Brockhaus and Efron.Atlas Mountains, Atlas, folded mountain system in the north-west. Africa, from several parallel chains. Length - 2,300 km. The atlas is divided into Moroccan and Algerian-Tunisian. Moroccan A. consists of three chains, of which the middle one, the highest, is called High A. (Tamjurt peak - 4,700 m). The Algerian-Tunisian A. consists of two chains, between which there is a plateau with salt lakes - shots. Northern slopes receive more rainfall; The plateau and southern slopes are dry. The population - sedentary and semi-nomadic Berbers (see) - is engaged in cattle breeding and gardening (olives, walnuts, figs). Iron, copper, lead, and zinc are mined in the Algerian Atlas. The Atlas Mountains are crossed by several railway lines; the most important of them: Bona - Tebessa, Philipville - Biskra, Oran - Figig.
The article reproduces text from the Small Soviet Encyclopedia.Atlas(Greek Atlas), a mountainous country in the north-west. Africa. It extends from the Atlantic Ocean from west to east along the Mediterranean coast for almost 2000 km, through Morocco, Algeria and Tunisia. It stands out as a special natural region of Africa, sharply contrasting in landscapes due to mountainous terrain, exposure-climatic differences and position at the junction of subtropical and tropical geographical zones.
Southern foothills of the Saharan Atlas.
The Atlas reaches its greatest height in Morocco, in the Er-Rif ridge, Middle and High Africa (Toubkal, 4165 m, the highest peak of Africa). To the west from the highest part the Moroccan Meseta descends in steps from a height of 1000-800 m. To the east, the Tel Atlas ridge extends along the Mediterranean coast, and the Saharan Atlas stretches along the southern edge. 1200-1500 m high. Between them at an altitude of 1000-1200 lie the plains of the Orano-Algerian Meseta. The spurs of the northern and southern ridges divide them into separate basins with large salt lakes - sebkhas (Chott esh-Shergi, etc.). In the east, the northern and southern ranges merge and are separated by a strip of meridional foothills from the coastal lowland of Tunisia.
The northern coastal part of Africa is an alpine folded structure with outcrops in the cores (Kabyle massifs) of ancient (Precambrian) metamorphic formations with a shell of thin Paleozoic and carbonate Triassic and Jurassic. The main role in the formation of this zone is played, however, by Cretaceous-Paleogene deposits, largely flysch. They form a system of tectonic nappes that moved from the north to the south and partially overlapped the foredeep made by the Molasse Miocene (Predrifsky, Predtelsky). In the structure of the more southern part of Africa and the West (Moroccan Meseta), a significant role is played by the geosynclinal Paleozoic strata, which experienced intense Hercynian tectogenesis. To the east, in the same strip (zone of the High Plateaus, including the Oran Meseta), relatively thin, weakly deformed shallow marine sediments of the Cretaceous and Paleogene and continental sediments of the Neogene lie on an older, probably Late Precambrian foundation. Even further south, in the zone of High and Saharan Africa, as well as in Middle Africa, the thickness of the Mesozoic increases and at the same time its folding noticeably increases. In the extreme east (in Tunisia), the folded structure is largely determined by highly plastic salt-bearing Triassic rocks. In the south, Africa is separated by a large fault (the South Atlas Fault) from the African Platform. Another fault with the subsidence of the central part of the Atlas structure runs along the Mediterranean coast, and manifestations of young volcanism and earthquakes are associated with it. Deposits of iron ores and polymetals are known in Africa.
Variegated lithology, climate fluctuations in the Pleistocene, and modern climatic differences determine the diversity of exogenous relief forms of Africa: on the highest peaks traces of ancient glaciation have been preserved (peaks, cirques, troughs, moraines); The ridges have dense and deep ancient erosional dissection. The interior areas are occupied by denudation and accumulative plains, cuesta ridges, and remnant plateaus. In the south, the mountain slopes are covered with gravelly screes, and physical weathering is actively occurring. In areas where limestone rocks are widespread, it is widely developed
This is a large mountain system, 2500 km long. Mountains stretch from Atlantic coast Morocco through Algeria and to Tunisia. Thus, the Atlas Mountains separate and protect the Mediterranean and Atlantic from the Sahara Desert and its high temperatures. The highest point of the mountains is in Morocco - the height of Mount Toubkal is 4167 meters, and in Tunisia the highest highest point- Mount Shaambi - reaches 1554 meters.
The name of this mountain range comes from the Greek myth, according to which the mighty Titan, nicknamed Atlas, held the vault of heaven on his shoulders as a punishment from the main god Zeus. According to the legend, for this Atlas was turned into a high mountain, and all the rocks around it became known as the Atlas Mountains.
In Tunisia, these rocks are almost devoid of vegetation and have a reddish color. They are interesting, first of all, for their oases. The first of them is Shebika, located north of the city of Tozeur. Once upon a time there was a small village in this area, but after three days of rain in 1969 it suffered a devastating flood that claimed hundreds of lives. Since then, no one has restored the destroyed village of Shebiku, and modern settlements have appeared closer to the valley. This area is notable for its small waterfall flowing straight from the rocks. The stream flowing from it flows along a narrow channel between the mountains, and then spills over the plain where the oasis lies. It is represented mainly by date palms and is irrigated thanks to a good irrigation system.
The second mountain oasis in the Atlas Mountains is located in Tamerz. It can be reached from Chebika along a 15 km long mountain road along the Algerian border. Like Shebika, Tamerza was heavily damaged during the 1969 flood. Now tourists can see here dilapidated houses, a snow-white mosque and the tomb of a marabout (saint). And the main attraction of the oasis is, of course, the Grand Cascade, which forms a natural pool. Tourists like to swim in it, as in Shebika.
You can also admire the beauty and grandeur of the Atlas Mountains by taking a ride on the legendary Red Lizard train. Back in the early 20th century, the Turkish Bey traveled on this train along with his retinue. The diesel locomotive consists of six different cars. Previously, the bey himself rode in one of them, his guards in another, his servants in a third, and so on. When equipping the train for tourist purposes, the engineers preserved its ancient appearance - some carriages are equipped with leather sofas, others with simple seats, like in an electric train.
The route of the tourist train starts from the city of Metlaoui, and the journey ends in Redeife - at the site of phosphate mining. The round trip lasts two hours, during which tourists can enjoy views of the rocky desert, oases, the Selja mountain gorge and canyons, and at the same time feel like residents of the Wild West.
A significant part of Africa's territory is located on the African continent. lithospheric plate. This ancient platform in the distant past was part of the huge continent of Gondwana. During the Triassic period, under the influence of external forces of the Earth, the high mountain ranges that existed on the ancient continent collapsed. the formation of horsts, earthquakes, and volcanic eruptions led to the formation of hilly plains, high plateaus, large basins and new mountain peaks. Africa is the only continent on which new mountain ranges were formed not in zones of folded structures. Africa stretches across the East African Plateau. The Drakensberg mountain system formed in the east of the southern part of the continent. The south of the mainland is bordered by the flat-topped Cape Mountains, and the Atlas Mountains stretch to the northwest. Their northern ridges are located directly at the junction of two lithospheric plates.
The Atlas Mountains, or Atlas, form the northwestern protrusion of the African continent, which is separated from southern Europe only by the Strait of Gibraltar. The northwestern coast of the continent is washed in the west by the Atlantic Ocean, and in the east and north by the Mediterranean Sea. In the south there is no clearly defined border with the Sahara; it consists of the southern foothills of the Atlas mountain ranges, into which desert landscapes are wedged.
The Atlas is the most significant elevation of northwest Africa. The mountain system stretches from the Atlantic coast through Morocco, Algeria to the very shores of Tunisia. It consists of the High Atlas, Tel Atlas, Saharan Atlas, Middle Atlas, Anti-Atlas ranges, internal plateaus and plains. The highest point in North Africa and the High Atlas is Mount Toubkal, reaching a height of 4,167 m. It is also the highest North African mountain. The atlas in this part of the mountain range is very reminiscent of the Alps and the Caucasus. In contrast, the Middle Atlas is plateau-like peaks with cut deep gorges. To the northeast, the continuation of the High Atlas is the Saharan Atlas. South of the High Atlas is the Anti-Atlas, the edge of the ancient plate raised by Cenozoic movements.
The origin of the Atlas Mountains is associated with deep faults that form lineaments (linear relief elements). Geologically, the Atlas Mountains are also notable for the fact that they serve as a recharge area for a veritable sea of groundwater in a vast artesian basin located under the world's largest
Along the Mediterranean coast, following the contours of the coast, rise the young folded mountain ranges of the Rif Atlas and Tel Atlas, up to 2,500 m high. They are a direct continuation of the mountains of Sicily and Southern Spain. Many Mountain peaks, including Toubkal, are extinct volcanoes.
Interestingly, the local population of the Atlas does not have a single name for this mountain system; there are only names for individual plateaus and ridges. The names themselves “Atlas Mountains” and “Atlas” are not used by the local population. They are accepted in Europe and originate in ancient myths, in which they were sung as the “Atlas Mountains”, the mythological titan Atlas, or Atlas, transformed by Perseus into African mountain for refusal of hospitality.
The existence of the Atlas Mountains first became known from the travels of the Phoenicians. Detailed description mountain system is contained in the works of Maxim of Tire. But the work of the outstanding German explorer of Africa Gerhard Rolf significantly expanded the understanding of the mountain range. Under the guise of a Muslim, he crossed the High Atlas, refined the map of mountain ranges, studied the largest oases, and from Algeria delved into the Sahara.
The Atlas Mountains, located near Marrakech, are considered the oldest. Their age is determined by the Cretaceous and Jurassic periods.
The features of the modern relief of the Atlas Mountains depend on a sharply continental and fairly dry climate. Intense weathering processes lead to the destruction of mountains and the accumulation of a large amount of debris at their feet, among which are high ridges with fairly steep slopes and sharp peaks. The relief is also distinguished by strong erosional dissection. Mountain ranges cut through deep gorges, the surface of the internal plateaus is intersected by a system of riverbeds - a legacy of a bygone era.
The Atlas Mountains have a Mediterranean climate. However, it is unpredictable and, depending on the altitude, quite severe. Thus, the High Atlas region has a typical mountain climate with cool, sunny summers and very cold winters. in summer it reaches +25⁰С, in winter the temperature sometimes drops to -20⁰С. The nearby Atlas Mountains have significant rainfall in winter period. Flooding is common in this area.
In summer, the surface of the internal valleys and plateaus warms up greatly, the temperature can reach +50⁰С. The nights, on the contrary, are quite cool and with frequent frosts.
The vegetation cover of the Atlas changes as you move from coastal to inland areas. The lower parts of the slopes are covered with groves of evergreen shrubs and cork oak forests. The higher slopes are covered with forests of yew and Atlas cedar. Internal valleys and plateaus with saline, poor soils are semi-deserts and dry steppes.
High in the mountains there are meadows that differ in their species composition from European mountain meadows. The tops of the ridges themselves are devoid of vegetation and are covered with snow for a significant part of the year. At the southern foot of the mountains there are desert zones with rare oases.
Animal world Atlas is represented by various species of animals from Africa and Southern Europe: hyrax, jerboas, hares, hyenas, jackals, wild cats and civets. On the rocks there is a magoth, as well as many snakes and lizards.
The population of the High and Middle Atlas is concentrated at the foothills of the mountains and in the valleys where the land is cultivated and irrigated for olives, citrus and other crops. Grapes are grown on the terraces of mountain slopes. The local population is also engaged in cattle breeding and cultivation of tough alpha cereal - a valuable raw material for the production of high-grade paper.
Later, the entire mountain system from Cape Kotey (modern Cape Spartel near Tangier) to Sirtes (Little Sirtes) began to be united under this name.
The length of the ridges is 2092 km.
The highest point is Mount Toubkal (4167 m), located in the southwest of Morocco.
Leader, Public DomainInitially, only part of the mountain system within ancient Mauretania was called Atlas, that is, the west and center of the modern Atlas.
The Atlas Mountains separate the Mediterranean and Atlantic coasts from the Sahara Desert.
View of the saddle (3940 m above sea level) under Mount Toubkal Kobersky, CC BY-SA 2.5 Populated mainly by Arabs and Berbers (Morocco), including Kabyles (Algeria).
The Atlas Mountains consist of the Tell Atlas, High Atlas, Middle Atlas, Saharan Atlas ranges, inland plateaus (High Plateaus, Moroccan Meseta) and plains.
Melintir, GNU 1.2 The ancient world first learned about the existence of the Atlas Mountains from the travels of the Phoenicians, and then from the periplus of Hanno and the voyage of Polybius, undertaken around 146 BC. e.
The first Roman to cross the Atlas Mountains was Gaius Suetonius Paulinus (42 AD).
A detailed description of the Atlas is contained in the writings of Maximus of Tire (2nd century AD).
The Atlas Mountains are located in the extreme northwest of Africa. They are a system of complexly branched ridges stretching for almost 2000 km from southwest to northeast. Their average height 1200-1500 m. In the south, the border with the Sahara is not clearly defined everywhere; in general it coincides with the southern foot of the Atlas mountain ranges.
The Atlas Mountains are located on the border of the Mediterranean and the Sahara; this country is characterized by a number of natural features characteristic of both Mediterranean and desert tropical landscapes. In some places, Saharan landscapes penetrate north into the mountain system. Typical
new Mediterranean landscapes occupy a narrow strip of coast no more than 150 km wide.
The Atlas Mountains are heterogeneous in tectonics and geological structure. Their northern part - the Er-Rif and Tell-Atlas ridges - was created by Alpine folding. The rest of the mountain system is formed by fragmented Hercynian structures involved in Paleogene tectonic movements. At the end of the Neogene, the mountainous country of the Atlas experienced strong movements of a vertical nature, which were accompanied by processes of volcanism, determined its modern outlines and separated it from the mountains of Southern Europe. Frequent earthquakes indicate ongoing tectonic activity.
The relief of the Atlas Mountains is characterized by strong erosional dissection. Deep gorges cut through the high ridges, with steep exposed slopes and sharp peaks; the internal plateaus are crossed by a system of channels devoid of permanent watercourses. Physical weathering processes occur intensively.
The Atlas Mountains are divided into northern and southern ranges, separated by a strip of internal plains and plateaus corresponding to intermountain troughs.
Northern Ranges - Er Rif in the west and Tell Atlas in the east they are separated by the Sheliff River valley. These young fold mountains 2000-2500 m high and stretch along the Mediterranean coast. They drop steeply to the sea, bordering bays convenient for navigation, or are separated from the sea by a narrow strip of low-lying coastal plain. The Mediterranean coast experiences uplifts and, in places, subsidence. Coastal terraces are almost not expressed.
166 Africa. Regional overview
Er-Rif (Rif Atlas) is a complex mountain range, highly dissected by erosion and most elevated in the central part. Its northern, limestone slopes are steep and precipitous; southern, shale - more flat. Tell Atlas forms three mountain ranges parallel to the coast. The ridge reaches its greatest height in the dissected crystalline massif of Djurjur (2300 m). In other places, the mountains are composed of limestone, clay, and marl. Karst is widely developed in limestones.
The southern ranges of the Atlas Mountains are folded and blocky. A ridge stretches from the Atlantic coast to the northeast High Atlas. In the Toubkal massif it reaches 4165 m - the highest height for the entire mountain system. The High Atlas is composed of Precambrian crystalline rocks. Its ridges are cut through by many river valleys, have jagged peaks and preserve traces of Quaternary glaciation - cirques, trough valleys and moraine ridges. East of the High Atlas stretches Middle Atlas. In its western part, it is a limestone, heavily karst plateau, broken by faults, with low extinct volcanic cones along the fault lines. Its eastern part is dominated by parallel anticlinal ridges separated by wide synclinal valleys. The High and Middle Atlas form the Moroccan Highlands. South of the High Atlas there is a ridge Anti-Atlas, representing the edge of the African Platform, uplifted by Cenozoic movements. Its continuation to the northeast is the ridge Saharan Atlas. These ridges are separated by narrow waterless gorges.
They are buried in rocky screes, and physical weathering is actively occurring in them.
Between the zones of the northern and southern ridges lies a strip of inland plains and plateaus, extending from the Atlantic Ocean northeast to the Mediterranean coast. Behind the narrow Atlantic accumulative lowland in the west, it rises stepwise Moroccan Meseta, adjacent to the Moroccan highlands. To the east are located high plateaus, bounded from the south by the Anti-Atlas and Saharan Atlas. The plateaus occupy a significant area and consist of vast basins separated by gentle rises.
Climatic conditions different parts of the Atlas Mountains are not the same. The northern coast and ranges have a typically subtropical Mediterranean climate, with dry, hot summers and mild, wet winters. In winter, sea air of temperate latitudes dominates. Significant amounts of precipitation are brought by westerly winds from the Atlantic. It rains from November to May, with a maximum in December-January (when the polar front occupies its southernmost position). In the west (Er-Rif and Jurjur) over 800 mm of moisture falls per year, mainly in the form of heavy rains; to the east the amount of precipitation decreases sharply, dropping to 300-200 mm near the Gulf of Gabes. Average temperatures in the winter months are higher than in Southern Europe (from +10 to +15°C). Almost every year there are short-term cold spells caused by the invasion of continental temperate air in the rear of cyclones. They are accompanied by snowfall in the mountains. Snow falls very rarely and quickly on the coast
Atlas Mountains 167
melts. In summer, this area is filled with marine tropical air, coming with northwest, north and northeast winds along the periphery of the Azores High. Downward air currents prevent precipitation; the weather is dry at this time. Summer temperatures are high, they rise from west to east from + 24 to +27 ° C and are only moderated by breezes on the coast. Sometimes hot and dry sirocco winds break through from the Sahara, raising the temperature to +35- + 40 °C and sharply reducing the relative humidity of the air.
The climate of the interior of the Atlas Mountains is sharply continental, arid and dry, with significant seasonal temperature ranges and, due to the high altitude of the area, quite harsh.
The interior of the Atlas - "a cold country with a hot sun"
In winter, a local anticyclone with continental air of temperate latitudes forms in the interior regions. Winters are quite cold, with average monthly temperatures dropping to
8---- + 5°C, and in closed depressions
And high mountains they often drop to -10°C and below. The tops of the mountains in winter are covered with snow, the thickness of which reaches 2 m. In the High and Middle Atlas, snow lies for more than 5 months. In summer the weather is hot and dry. Daytime temperatures are + 26 - + 28°C, maximum - up to + 50°C (with a hot southern wind). Mountain ranges block moist air masses from entering the interior, and precipitation there is less than 500 mm per year. Maximum precipitation
winter everywhere. Agriculture in almost the entire region requires artificial irrigation.
The river network of the Atlas Mountains is poorly developed. The rivers are fed mainly by rain, and only those rivers that flow from the Moroccan highlands and the Jurjour massif additionally receive snow nutrition. Permanent watercourses irrigate areas adjacent to Atlantic Ocean And Mediterranean Sea. The largest rivers are Sheliff (700 km) and Muluya. They do not dry out in the summer, although costs fluctuate sharply throughout the year. In winter, water flow in Sheliff reaches 1400 m 3 /s, in summer it drops to 4 m 3 /s. In the interior of the Atlas there is a network of dry and dry riverbeds (wa-di), filled with water only after irregular rainfall. The high plateaus are characterized by vast, drainless salt lakes - shottas, which remain dry for a significant part of the year and are covered with a salt crust.
In vegetation and soil cover, as well as in relief, climate and hydrography, there are differences between the coastal and inland regions of the Atlas Mountains. On the coast and in the lower parts of the mountain slopes (up to an altitude of 400-500 m), thickets of hard-leaved evergreen shrubs (maquis) of myrtle, gorse, broom, cistus, oleander, strawberry and olive trees are developed on brown soils. However, most of the coast and adjacent foothill areas are plowed and occupied by citrus, olive, fruit, vineyards and grain crops.
Above the maquis (up to 1200-1300 m) forests of evergreen cork oak grow, the second tier and undergrowth of which consist of plants typical of the maquis; entwines tree trunks
168 Africa. Regional overview
ivy. The forests are located on leached brown soils.
Oak forests are replaced by mixed forests (from an altitude of 1200-1300 m), then coniferous forests (about 1800-2000 m). Mixed forests consist of evergreen species (holm oak), as well as trees with falling leaves (Lusitanian oak) and conifers (Atlas cedar); mountain forest brown soils develop under them. Coniferous forests are formed by Atlas cedar, which tolerates cold well, as well as yew. The understory and undergrowth of mixed and coniferous forests consist of maple, chestnut, wild pear, as well as holly and barberry.
The leeward slopes of Tell Atlas are occupied by forests of Aleppo pine with an undergrowth of Berber thuja, sparse juniper bushes, and open forests of holm oak with an undergrowth of Aleppo pine.
The upper border of the forest is formed by twisted, low-growing juniper trees.
velnikami and lies at an altitude of about 3000 m. Higher up, among rocky placers, in depressions there are spots alpine meadows, significantly inferior in their species composition to the mountain meadows of Europe. The tops of the highest ridges are devoid of vegetation and are covered with snow for a significant part of the year.
The internal plateaus and valleys of the Atlas Mountains with poor gray soils, often saline soils (salt marshes) are dry steppes and semi-deserts. Xerophytic turf grasses, rare shrubs and trees grow here. Grasses dominate over shrubs in the driest central and southern regions. The main plants are feather grass, alpha grass, wormwood, gorse, jujube bush, and halophytes grow around the chotts. In Morocco, the low-growing chamerops palm and argan tree grow among the cereals; There are groves in Tunisia coniferous trees and gum acacia. Shrubs and low-growing trees are characteristic of areas with better moisture, often forming dense thickets; Under them, on the carbonate weathering crust, the soils of Terra Rossa develop.
The Anti-Atlas and Sahara Atlas ranges, forming a mountain barrier on the border with the Sahara, already have typically desert landscapes. Only on the upper parts of the northern mountain slopes and on peaks that receive little rainfall are rare groves of Aleppo pine, arborvitae, holm oak (in the Saharan Atlas) and juniper (in the Anti-Atlas). At the southern foot of the mountains there are rare oases in which date palms are cultivated.
The fauna of the Atlas combines species from Southern Europe and Africa.
Sahara 169
There are many rodents here (hares, jerboas), and herbivores - hyraxes - can be found here. Among the predators, jackals, civets, wild cats and hyenas are ubiquitous. A tailless macaque lives on the rocks. Lots of lizards, snakes, various insects. Agriculture periodically suffers from locust attacks.
Sahara
The Sahara occupies a vast territory. It stretches from the Atlantic coast to the Red Sea and from the Atlas Mountains and the Mediterranean coast to a line passing through downstream the Senegal River, Lake Chad, Khartoum on the Nile and Massawa on the Red Sea coast. The length of the Sahara from north to south is about 2000 km, from west to east - 6000 km, area - 8.7 million km 2. The landscapes of tropical deserts dominate here.
The Sahara is entirely located within the African platform. The surface of the territory is covered with strata of limestone, sandstone and clayey rocks of different ages. They form stratified plains and plateaus 300-500 m above sea level. In places, an ancient folded foundation protrudes to the surface or ancient intrusions emerge, forming crystalline plains and high highlands. Cuest ridges are developed in areas of the platform with a monoclinal structure.
In the west of the Sahara there are low plateaus of crystalline rocks (Karret-Yetti, El-Eghlab). They surround the vast El-Juf basin (syneclise of the platform) and the Er-Rir depression (pre-Atlas foothills).
deflection). Most of The trough is made of sedimentary strata and is expressed in relief by inclined, strongly dissected plateaus.
The Ahaggar and Tibesti highlands rise in the central part of the Sahara. They are composed of crystalline and volcanic rocks (volcanic peaks on Ahaggar, lava plateaus and extinct volcanoes on Tibesti). The main peak of Tibesti - dormant volcano Emi Koussi (3415 m) with a large crater is the highest point of the Sahara. Recent volcanic activity is evidenced by hot springs and emissions of sulfur dioxide gases. Mountain ranges have a highly dissected topography, their slopes are steep and rocky; a mass of coarse debris has accumulated at the foot.
The Ahaggar and Tibesti highlands are surrounded by cuesta ridges, especially well developed on the northern side. The cuestas are separated by wide longitudinal valleys, their ledges are dissected by dry transverse narrow gorges. To the north of the central Saharan highlands lies the tectonically highly fragmented Libyan Sahara with volcanic landforms (the Jebel es-Aswad plateau), rocky and sandy deserts. From the south, the peripheral parts of the Sudanese basins adjoin the highlands.
The east of the Sahara is occupied by the Libyan, Arabian and Nubian deserts. The Libyan desert does not have dry river beds, its north is occupied by lowlands, the rest is occupied by structurally stepped and remnant plateaus. Characteristic deep depressions and the world's greatest accumulations of sand. The Qattara Depression (-133 m) is one of the deepest dry depressions on the globe. In the depressions there are the oases of Farafra, Bahariya, Dakhla and
170 Africa. Regional overview
Kharga. In the Arabian and Nubian deserts, the crystalline basement is elevated and in places covered by strata of Mesozoic sandstones. Here table plateaus rise up to 2000 m high, intersected by deep dry gorges, indicating strong erosional dissection in the previous wetter era. Short dry beds of ancient rivers are directed towards the Nile, their sources lie on the slopes of the Etbai ridge - a horst-block massif that survived the collapse of the arch of the Nubian-Arabian anteclise.
In the Sahara, due to processes of intense physical weathering, masses of clastic material have accumulated. About 20% of the area is occupied by sand accumulations (ergs). They are developed mainly in depressions between cuesta plateaus and in vast closed basins. There are especially large accumulations of sand in the Libyan Desert, where the relative height of the dunes reaches 300 m, and in the northwestern part (Great Western and Great Eastern ergs). A significant part of the Sahara is occupied by rocky deserts (hamads), sand and pebble deserts (regs, serirs). Hamads are located on elevated areas and are composed of bedrock. Regs are distributed mainly on the slopes of tectonic basins and troughs, from where sandy material is washed out by water or carried away by the wind. Seriras lie in the most low areas areas of subsidence, occupying the bottoms of depressions (sebkhs).
Protective crusts, mainly limestone-gypsum, are widely developed in the Sahara. They protect vast plateaus from destruction and have different ages. The youngest of them are the Shotta in the Serir depressions.
In regs and hamadas, the crusts are more ancient and dense.
The climate of the Sahara is sharply continental and desert. Throughout the year, dry tropical air with low relative humidity (sometimes below 25%) prevails, and downward air currents (trade winds) predominate. Clouds over the Sahara are a rare phenomenon. The transparency and dryness of the air cause high insolation. The Sahara is one of the hottest deserts in the world, with sharp daily and annual temperature fluctuations. In summer, the heat reaches +50 °C and higher, the soil surface warms up to + 60 --- +80 °C.
The desert in July, with the exception of the Atlantic and Mediterranean coasts, is outlined by an isotherm of + 30 °C. The air above is especially hot western part Sugars, covered by an isotherm of +35 °C. Passing atmospheric depressions cause severe sand and dust storms - one of the main disasters of the desert. On hot days, with strong and uneven heating of the air, visibility conditions are distorted and mirages occur.
The absolute maximum temperature of the Earth was recorded in Tripoli (+58°C in the shade)
During the winter months the air is cooler and more stable. The central and northwestern parts of the Sahara are cooling significantly (up to 10 °C). Coastal areas, due to the moderating influence of the ocean and seas, have a higher temperature. During the day the temperature stays around +20 --- +25°C,
At night, due to strong radiation, the earth's surface drops to 0 °C.
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Negative temperatures found at the heights of the Sahara.
Much of the Sahara receives less than 50 mm of precipitation per year. In inland areas there is sometimes no rain for several years. The Libyan Desert and the area southwest of Ahaggar (Tanezruft) are especially rainless. A slight increase in precipitation (up to 100-150 mm) is typical for the Central Saharan highlands. Precipitation falls mainly in the form of occasional showers, sometimes of a torrential nature. A significant part of them evaporates before reaching the earth's surface. Other sources of moisture include fog (frequent in spring on the Atlantic coast) and dew. Along with the low amount of precipitation in the Sahara, evaporation is extremely high, so the moisture content of the territory is practically zero.
There is more precipitation on the northern and southern edges of the Sahara. In the north they fall in winter, spring and autumn and are associated with the penetration of cyclones of the polar front, in the south - in summer and are caused by cyclones of the tropical front.
There is almost no surface water in the Sahara. The desert is crisscrossed by a network of dry wadi beds. Most of them diverge from the Saharan highlands, which served as watersheds in the past, and end at closed depressions. Only after rare rains do they fill with water, which dries up after a few days, and sometimes hours. Many wadis have underground drainage.
The only major permanent watercourse in the Sahara is the Nile, which receives its nourishment from outside the desert. On the outskirts of the Sahara and in some mountainous areas there are lakes with clean water. They have survived from the previous wet period and are fed by underground watercourses.
kami. Shots are also available. Groundwater, which is richest in sandy deserts and wadis, is of great value. They are the main source of water supply in
Typical landscapes of the Sahara
villages outside the Nile Valley.
The soil and vegetation cover of the Sahara is sparse, discontinuous and extremely sparse. Vast areas are almost completely devoid of soil and vegetation. The soils are poorly developed, primitive, but contain many nutrients. The vast majority of plants are xerophytes and ephemerals, striking in their ability to adapt to harsh conditions. Ephemera after random rains in a short time
172 Africa. Regional overview
For some time they have time to germinate, produce flowers and fruits and again go into a dormant state, which can last for more than one year in anticipation of the next rain. Rocky deserts are especially lifeless. Sandy deserts absorb moisture from dew and rare rains. Sands are supported by long-rooted leafless shrubs, subshrubs and grasses. The most common among them are Saharan gorse, ephedra, and drine. Among the stones and on the sands you can find the rose of Jericho - a plant with a short stem and bent branches. Along the Atlantic coast, due to high air humidity, dew and fog, quite dense thickets of quinoa, as well as low-growing cactus-like spurges and lichens, have developed.
The Ahaggar and Tibesti highlands are better hydrated than other areas of the Sahara. Many rivers originate from their peaks, some of which are preserved.
It creates permanent watercourses in deep and shady gorges. Trees and shrubs climb high along them, forming quite dense thickets in places. Vegetation varies with altitude. In the lower, Saharan-tropical zone, typical representatives of the Sudanese flora (dum palm, acacia) are found; in the middle, Saharan-Mediterranean, oak, juniper, oleander, olive tree, myrtle and cypress grow. On the peaks, especially on Tibesti, there are patches of mountain-steppe vegetation.
One of the attractions of the Sahara is the oases, which are green spots among the vast desert spaces. They occur where there is water on or close to the surface. One of the largest oases in the world is the Nile Valley. Other oases arose near artesian wells. The main culture of the Saharan oases is date palm, in the shade of which fruit trees and shrubs and cereals are grown.
At the southern border of the Sahara, thickets of bushes and tough grasses appear. In the north, on the border with the Atlas region and on the Mediterranean coast, wild pistachios, oleanders, and jujubes are found.
The fauna of the Sahara is poor in species, but quite rich in individuals. Animals are adapted to harsh conditions, they are hardy, able to move quickly in search of water and food. Some of them are limited in their distribution to better moistened areas or water sources. The most typical for the Sahara are addax and oryx antelopes, gazelles, mountain goats, and among predators are jackals, hyenas, foxes, and cheetahs. Birds are represented by migratory and sedentary species, among the latter
Sudanese-Guinean country 173
desert raven, lizards predominate among reptiles, snakes and turtles are found. There are crocodiles preserved near rare bodies of water.