Eurasia

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Eurasia

(yo͝orā`zhə, –shə), land mass comprising the continents of EuropeEurope
, 6th largest continent, c.4,000,000 sq mi (10,360,000 sq km) including adjacent islands (2015 est. pop. 740,814,000). It is actually a vast peninsula of the great Eurasian land mass.
..... Click the link for more information. and AsiaAsia
, the world's largest continent 17,139,000 sq mi (44,390,000 sq km) and most populous (2015 est. pop. 4,419,898,000), with nearly three fifths of the world's total population.
..... Click the link for more information. , in which Europe is geographically a western peninsula of Asia, rather than a separate continent.

Eurasia

the earth’s largest continent. It consists of two parts of the world, Europe and Asia. Including its islands, Eurasia occupies an area of approximately 53.4 million sq km, of which the islands account for about 2.75 million sq km. The extreme mainland points of Eurasia are Cape Cheliuskin (77°43’ N lat.) in the north, Cape Piai (1°16’ N lat.) in the south, Cape Roca (9°34’ W long.) in the west, and Cape Dezhnev (169°40; W long.) in the east. A number of islands in southeastern Eurasia are located in the southern hemisphere. Eurasia is surrounded by the Atlantic Ocean on the west, the Arctic on the north, the Indian on the south, and the Pacific on the east, as well as by their outlying seas. In the southeast the Australo-Asiatic seas separate Eurasia from Australia; in the northeast, the Bering Strait separates it from North America; and in the southwest, the Straits of Gibraltar and the Mediterranean and Red seas separate it from Africa, to “which Europe is joined by the Suez isthmus. The need for a geographic designation for the entire continent is a result of the continuity of the land mass, the modern tectonic consolidated nature of the mainland, the unity of many climatic processes, the considerable community of development of the organic world, and other manifestations of natural and historical unity, as well as by the necessity of taking into account the significance of territorial integrity in evaluating social and historic phenomena. The most convenient concept was that of “Eurasia,” which was introduced into geology and geography by E. Suess in 1883.

Eurasia has been an arena for the most ancient civilizations. Thousands of years of farming culture have transformed the natural landscape of lowland plains of southern and eastern Asia, the oases of Central, Middle, and western Asia, and the southern coasts of Europe. The territory of most of Europe has undergone radical transformations, and a considerable part of Asia has been developed. A modern cultivated landscape predominates on the territory of most of Europe, on the Sung Liao, North China, and Indo-Gangetic plains, the Indochinese Peninsula, and the islands of Java and the Japanese archipelago.

Topography and history of development. Eurasia is distinguished by the considerable complexity of its geologic history and the mosaic nature of its geologic structure. The core of Eurasia was joined together from fragments of several ancient continents: in the northwest, Laurentia, whose eastern part after Cenozoic subsidences in the area of the Atlantic Ocean separated from North America and formed the European protrusion of Eurasia; in the northeast, Angaraland, which in the late Paleozoic age was joined to Laurentia by the folded structure of the Urals, as a result of which Laurasia (the old name of the Canadian Shield), which existed until the middle of the Mesozoic age, was formed; and in the south, Gondwanaland, after whose collapse the northeastern parts of Gondwanaland (the Arabian and Indian platforms) joined Eurasia.

The structural design of the modern topography of Eurasia was laid down as early as the Mesozoic age, but the formation of basic surface features resulted from very recent tectonic movements, which enveloped Eurasia during the Neocene and Anthropogenic periods and were more intensive than anywhere else on earth. They consisted of far-reaching vertical displacements—arched-block uplifts of mountains and highlands and settlings of depressions, with partial reworking of numerous structures. The uplifts embraced not only alpine folded structures but also rejuvenated and frequently regenerated mountain topography in more ancient structures that had undergone leveling before the Cenozoic age. The intensity of the most recent movements was responsible for the prevalence of mountains in Eurasia (the average elevation of the continent is 840 m) and the formation of the highest mountain systems (the Himalayas, Karakoram, the Hindu Kush, and the Tien-Shan), with peaks exceeding 7,000–8,000 m. The massive Southwest Asian highlands, the Pamirs, and Tibet were elevated to great heights. The regeneration of mountains in a broad belt from Gissar-Alai to Chukchi, as well as the Kunlun and Scandinavian mountains, is associated with these uplifts. The midlands of the Urals, Central Europe, and other areas and, to a lesser degree, broad tablelands and plateaus (the Central Siberian Plateau, the Dekkan, and others) were rejuvenated during the process of the most recent uplifts. To the east the mainland is rimmed by outlying elevations (the Koriak Highland and the Sikhote-Alin’ Mountains) and is followed by mountainous island arcs, among which the eastern Asiatic and the Malayan are distinguished.

Rift structures, such as the Rhine graben and the depressions of Lake Baikal and the Dead Sea, play an important role in fhe topography of Eurasia. Very high seismicity is especially characteristic of recent folded zones and structures of regenerated mountains; only South America compares with Eurasia in terms of the intensity and frequency of destructive earthquakes. Volcanic activity (lava sheets and volcanic cones of Iceland and the Armenian Highland, active volcanoes of Italy, Kamchatka, and the island arcs in the eastern and southeastern parts of Asia, and extinct volcanoes of the Caucasus, Carpathians, and Elburz) often played a part in creating the topography of young elevations.

Very recent subsidences have led to the submersion of many continental borderlands and the isolation of archipelagoes (the Far East, the British Isles, and the Mediterranean Sea basin) contiguous to Eurasia. In the past, the seas advanced repeatedly onto various parts of Eurasia. Submerged plains, which were subsequently dissected by glacial, river, and lacustrine waters, were formed from the deposits of these seas. The largest plains of Eurasia are the Eastern European (Russian), the Central European, the Western Siberian, the Turan, and the Indo-Gangetic. Sloping and socle plains are widespread in many areas of Eurasia. Ancient glaciation has had a marked influence on the topography of northern and mountainous regions of Eurasia. The world’s largest area of Pleistocene glacial and aqueoglacial deposits is found in Eurasia. Modern glaciation has developed in many highlands of Asia (the Himalayas, Karakoram, Tibet, Kunlun, the Pamirs, and the Tien-Shan), in the Alps and Scandinavia, and, especially intensively, on the arctic islands and in Iceland. Subterranean glaciation— permanently frozen rock and veined ice—is more extensive in Eurasia than in any other part of the world. Karst processes have been developed in areas of limestone and gypsum deposits. Desert forms and types of relief are characteristic of arid regions of Asia.

Various minerals are found in the interior parts of Eurasia. (See Natural features: Geological structure and mineral resources in ASIA and EUROPE.)

Climate. The climate of Eurasia is influenced by powerful centers of atmospheric activity, both year-round (the Azores and Hawaiian anticyclones and the Icelandic and Aleutian lows) and seasonal (the winter Asiatic anticyclone centered over Mongolia and the summer low over southern Asia). The enormous dimensions of Eurasia and the complexity of its topography determine the extreme diversity of climatic conditions and, as in no other area of the world, the broad distribution of continental types of climate. Latitudinal distinctions among cold, temperate, and hot climatic zones are very great. In the arctic and subarctic areas, arctic-front cyclones are in effect year-round; at temperate latitudes, polar-front cyclones; and at lower latitudes, tropical-front cyclones (typhoons), which frequently bring about hurricane-force winds. The transition from a dry summer to a moist winter in the western sector of the subtropical zone (the Mediterranean climate) is associated with seasonal shifts in the general atmospheric circulation. Winter rains there are caused by polar-front cyclones. There is no tropical zone in Europe; in Asia it is found only in the southwest (the Arabian Peninsula and the Tar desert), where a tropical desert climate prevails, and to the east it is replaced by subequatorial zones. In the equatorial zone there is a convergence of air masses flowing from the north and south, causing the formation of abundant precipitation throughout the year. There are also distinct differences in sectors (the replacement of continental and transitional types of climate in the interior of Eurasia by oceanic types in most of the periphery). The influence of the ocean on the climate is particularly noticeable in Western Europe, where air flowing out along the periphery of the Azores anti-cyclone is included among the westward-moving air masses. Cyclones originating in* the area of the Icelandic low are moving in the same direction, along the arctic and polar fronts. In moving to the east, Atlantic air gradually loses its moisture and is transformed into a continental variety. Air masses from the Pacific and Indian oceans penetrate into land interiors only at certain times (the cyclone and monsoon seasons). Arctic air, which is restrained by latitudinal orographic barriers only in the interior of the mainland, flows freely from the north into Eurasia. High atmospheric pressure, which contributes to stagnation of the air, great heat radiation, and low surface temperatures, prevails in the inland areas of Eurasia during the cold seasons. From here continental winter monsoons move to the east and south. Summer air temperatures, on the other hand, are high. Sector climatic changes are aggravated by sea currents. Warm currents create positive winter and yearly temperature anomalies off the coasts of northwestern Europe and Japan; cold currents create negative summer and yearly anomalies off the coasts of eastern Asia. Altitudinal zonality of climatic conditions and their change owing to the presence of declivities are clearly expressed in mountainous regions. The enclosed isolation of inland areas of Eurasia, with which sharp contrasts in humidification are associated, is distinctly shown. Chilled air stagnates over the vast highlands. Local centers of atmospheric activity and unusual variations in high-altitude climates are formed (for example, the climate of high-altitude deserts of the Pamirs and Tibet).

Rivers and lakes. Eurasia is drained by a complex system of rivers that empty into four oceans. Even the largest rivers of Europe (the Volga and Danube) yield in size to the great rivers of Asia (the Lena, Enisei, Amur, Ob’, and Yangtze). Many of the rivers of Eurasia are important transportation routes and major sources of hydroelectric power and water for field irrigation. The world’s largest area of inland drainage is located in Eurasia and flows into undrained seas (the Caspian and Aral seas) or large undrained lakes (Balkhash, Lop Nor, and others); some rivers disappear in deserts. In addition to undrained lakes, there are numerous large circulating lakes in Eurasia (Lakes Baikal, Ladoga, and Onega).

Flora and fauna. In terms of flora and fauna more than half of Eurasia belongs to the Holarctic, in many regions of which there is a noticeable depletion of the organic world caused by the most recent uplifts and glaciations and the incursion of the seas. The southern part of Eurasia is covered by the flora of the Palaeotropical region and fauna mainly of the Indo-Malayan region. Eurasia is distinguished from other continents by the exceptionally broad distribution of taigapermafrost, podzolic, and desert-steppe types of soil formation, as well as by the diversity of types of mountainous soils. Basic changes in soils and in the organic world occur with shifts in latitude (from tundras through forest areas of the temperate zone to steppes, deserts, various areas of the subtropical zone, savannas, and dry tropical and humid equatorial forests), as well as with removal from oceans and the changing altitudinal zones in the mountains.

Natural sectors and zones The division of Eurasia into sectors that are essentially distinguished in terms of natural features is associated with various distances and degrees of isolation of individual land areas from sources of humidification. Six sectors are identified in Eurasia: two oceanic (western and eastern), two transitional, one continental, and one sharply continental. The western oceanic sector embraces all of Western Europe and the major part of western Asia; the eastern oceanic sector is limited to a smaller area of Pacific Ocean coastal regions and is distinguished by the importance of monsoons, which have an impact on various aspects of nature. The remaining sectors occupy the interior regions of Eurasia. The sharply continental sector, found only in Eurasia, is located to the east of the continental sector; this is a result of the prevalence of a westerly movement of air masses and the pattern of orographic barriers, which retain a significant portion of humidity on their outer slopes.

Large segments of a planetary system of geographic zones are found in the territory of Eurasia, with its considerable differences in latitudinal positions. A zone of arctic deserts with subzones of ice and rock deserts and with a cold-desert type of mountainous landscape is located in the arctic belt. In the subarctic belt tundra and tundra-forest zones are distinguished; in the mountains, a tundra-cold-desert group of altitudinal zones; in the east there are widespread stone-pine tundra-forests. In the temperate belt, the change of zones with latitude (forest zone with subzones of taiga, mixed and broad-leaved forests, forest-steppe, steppe, semidesert, and desert) is characteristic of the continental sector. In the sharply continental sector of Eurasia, where there are considerable increases in areas covered with mountains, latitudinal zonality is primarily mamrested in spectra of altitudinal zones. The influence of the oceans causes changes in zonal boundaries in transitional and oceanic sectors. For example, in the East European Plain, zones alternate from the north-west to the southeast; in the extreme south of the temperate zone they alternate from west to east, from the forests of France to the forest-steppes of the Carpathian region, the steppes of the southern Ukraine, the semideserts and deserts of Kazakhstan and Central Asia, the steppes and forest-steppes of Mongolia and Tungpei, the forests of the Manchurian-Korean mountains, and the mountains of northern Japan. Tundra-forest, stone-pine forest, meadow-forest, and desert-steppe spectra of altitudinal zones are characteristic in the mountains. Zones alternate from west to east and in the subtropical belt (hard-leaved forests and shrubs of the Mediterranean region, subtropical steppes and semideserts of Transcaucasia and Asia Minor, and subtropical deserts of the Iranian highland, southern Turkmenistan, and southern Central Asia). Spectra of altitudinal zones based on forests (meadow-forest-steppes in the west and meadow-forests in the east) are characteristic of the mountains of the oceanic sector. Desert-steppe spectra predominate in the interior of Eurasia; in the highlands of the Pamirs and Tibet, high-mountain desert spectra predominate. A tropical belt is found in Arabia and the Tar desert, with zones of tropical semideserts and deserts, and, in the mountains, desert-steppe and desert spectra of altitudinal zones (in the more humid Western Himalayas there is a meadow-forest spectrum). To the east, at tropical latitudes, extends the northern, subequatorial belt, with zones of alternating humid sub-equatorial forests (mainly on the windward slopes) and savannas (predominantly in the inner regions of Hindustan and Indochina). Meadow-forest and forest-steppe spectra of altitudinal zonality have been developed in the mountains of this belt. In the equatorial belt (southwestern Sri Lanka, southern Malacca and the Philippines, and the Greater Sunda Islands) there are damp equatorial tropical forests (gilea), in the mountains there are combinations of tropical forests and mountainous equatorial landscapes (paramos). Forest and savanna landscapes of the southern subequatorial belt pre-dominate on the Lesser Sunda Islands.

There is no generally accepted division of Eurasia into natural regions. The scheme of regions introduced below proceeds from a division of Eurasia into natural and topographic areas, each of which is characterized by morphotectonic unity, the common quality of recent tectonic development, circulation processes of climate formation, and regular sets of natural zones. Certain areas share common features that make it possible to combine them into larger groups, although each is distinguished from the others by diverse sets of characteristics.

Atlantic region group. The Atlantic region group is characterized by considerable neotectonic mobility. Oceanic climatic types, which have a noticeable influence on all components of the natural environment, predominate. A strong depletive influence of ancient glaciation on the organic world is found.

FENNOSCANDIA. In Fennoscandia there is a predominance of socle plains on a crystalline shield and of regenerated midlands on Caledonian folded structures (the Scandinavian highland). There are centers of modern glaciation and considerable traces of ancient glaciation. Glacial lakes, as well as fjord and skerry coasts, are found. The climate is moderately cold; the North Atlantic current reduces the severity of the winter. To the north the taiga is bordered by tundra-forest and tundra; to the south, by mixed forests. In the mountains there is a tundra-forest type of altitudinal zonality.

ICELAND. Iceland is characterized by ancient and active modern volcanic activity, a cold oceanic climate with a moderate winter, intensive recent glaciation, sharp insular depletion of the organic world, and mountainous tundra and tundra-forest.

BRITISH ISLES AND CENTRAL EUROPE (the nonalpine areas of France, the midlands of Central Europe, and the Central European Plain). The British Isles and Central Europe are marked by widespread rejuvenated folded-block lowlands and midlands with Hercynian plicate structure; in places there are layer elevations and cuesta ridges. The folded foundation of the Central European Plain is buried under mid-Cenozoic stratifications and ancient glacial and aqueoglacial detrital deposits of an aggradation plain. The natural vegetation consists of depleted broad-leaved and mountainous mixed forests, as well as heath wastelands.

ALPS AND CARPATHIAN MOUNTAINS (WITH SOUTHERN PIEDMONT PLAINS). The region of the Alps and Carpathian Mountains consists of midlands and highlands uplifted by the most recent movements of alpine folded structures and of sloped plains of intermontane and piedmont depressions. Numerous traces of ancient mountainous glaciation are found, and there is intensive recent glaciation. In the mountains meadow-forest spectra of altitudinal zones predominate; in the plains, forest-steppe landscapes predominate.

Northern Eurasia. Northern Eurasia is characterized by vast plains (the East European and Western Siberian), divided by the Urals, with a relatively stable platform structure. The climate and topography are of the transitional-continental and continental types. The topography, especially in the northwest, is considerably depleted by ancient glaciation. The progression of natural zones in the temperate belt is clearly defined.

EAST EUROPEAN (RUSSIAN) PLAIN. The East European (Russian) Plain consists of an ancient plain on an immobile platform foundation. In the northwest there are traces of ancient glaciation. Natural zones progress from the northwest to the southeast between the transitional and continental sectors (from tundras to deserts). Forest and steppe landscapes predominate.

URALS. The Urals are a region of folded midlands, low-lands, and socle plains, moderately rejuvenated by very recent uplifts. Tundra-forest spectra of altitudinal zones are found in the north; semidesert-steppe spectra are found in the south. In the central parts of the Urals, foothill steppes give way to forests and meadows with increasing elevation.

WESTERN SIBERIAN PLAIN. The Western Siberian Plain is an aggradation plain that is neotectonically quiescent and is low-lying over broad expanses. Its foundation is composed of marine deposits, which are overlain in the north by glacial deposits and in the south by aqueoglacial and river detrital deposits. The climate is continental. The latitudinal geographic belts and natural zones progress from tundra to dry steppes with prevailing swampy, dark-coniferous taiga.

Mountains and islands of the arctic.EURASIAN SECTOR. The Eurasian sector consists of technically shattered, basically low-mountain and middle-mountain archipelagoes (Spits-bergen, Franz Josef Land, Novaia Zemlia, and Severnaia Zemlia) and islands. There is a predominance of mountainous glacial and rocky arctic deserts and, in part, mountainous tundras.

Upper Siberia and Mongolia. Upper Siberia and Mongolia are characterized by platforms and ancient folded structures with high neotectonic mobility and a predominance of midlands and plateaus. The climate is continental and sharply continental, with relatively little snowfall in the winter. The region has the greatest distribution of underground glaciation found anywhere in the world. Ancient glaciation occurred only in individual centers. There is a predominance of mountainous light-coniferous taiga. Landscapes are depleted mainly as a result of the seventy of modern climatic conditions.

CENTRAL SIBERIAN PLATEAU. The Central Siberian Plateau consists of steplike plateaus, dissected by erosion, with a moderate range of neotectonic uplifts and widespread development of traps. There are hills and mountains (the Enisei and Angara ridges and the Putorana plateau). The climate is of the severe continental variety. There is a light-coniferous taiga and, on the western slopes, dark-coniferous taiga.

INNER YAKUTIA. Inner Yakutia consists of the lowland Central Yakut Plain (in the area of the Lena-Viliui trough) and the Aldan plateau, which was created by the uplift of an ancient crystalline shield. The climate is sharply continental and dry. Light-coniferous taiga is combined with islands of forest-steppe and winnowed sands.

NORTHEASTERN SIBERIA. Northeastern Siberia is a complex combination of folded-block structures of various ages; it consists of neotectonically regenerated midlands and low-lands (the Byrranga, Verkhoiansk, Cherskii mountain systems and the Koriak Highland), plateaus (lukagir, Alazeia, and others), and extensive aggradation plains, which frequently were submarine plains (the Northern Siberian, lanaIndigirka, and Kolyma depressions). The climate is sharply continental, with the poles of cold of the northern hemi-sphere; in the northeast there is a cold oceanic climate. There are small centers of ancient and recent glaciation. Tundra, mountainous tundra, and stone-pine tundra-forests predominate. Diverse relict flora is found in the northeast. In the south are sparse forest and northern taiga.

MOUNTAINS OF SOUTHERN SIBERIA AND MONGOLIA. The mountains of southern Siberia and Mongolia consist of highlands (the Altai and Saians and the Kodar Range) and midlands (Transbaikalia, the Hantai, the Hentei, and the Stanovoi Range), regenerated by the most recent tectonic movements of structures with various ages of the Paleozoic and, in places, the Precambrian and Mesozoic periods. Deep tectonic depressions are covered by lakes and aggradation plains. There are centers of mountain glaciation. Mountain taiga predominates; in the south, mountainous forest-steppe.

Inner Eurasia. Inner Eurasia is a territory of sharply increased neotectonic mobility. Very high uplands and mountains are found. There are vast intracontinental depressions, with a predominance of continental and sharply continental climate, as well as inland drainage. There are large undrained lakes. The fauna and flora of mountain and plains desert-steppe landscapes was depleted in many areas by very recent uplifts, which led to isolation from moist air masses, and by the influence of ancient glaciation.

PLAINS OF INNER KAZAKHSTAN, THE CASPIAN REGION, AND MIDDLE AND CENTRAL ASIA. The plains of inner Kazakhstan, the Caspian Region, and Middle and Central Asia consist of aggradation and socle plains (Karakum, Kyzylkum, Takla-Makan, and Gobi) and tablelands with sections of low-mountain and hummocky areas. The climate is continental (in the east it is sharply continental temperate; in the south, dry subtropical). Deserts and semideserts predominate.

MOUNTAINS AND UPLANDS OF MIDDLE AND CENTRAL ASIA. The mountains and uplands of Middle and Central Asia consist of midlands and highlands (Tibet, the Pamirs and eastern Hindu Kush, Karakoram, Kunlun, and Tien-Shan), uplifted by intensive neotectonic movements. There are intense centers of ancient and recent glaciation. Permanently frozen ground is present. There is a spectrum of altitudinal zones from mountainous deserts in the foothills through mountainous steppes and (on the northern slopes) forest-steppes to mountain meadows and nivals and, in places, high-mountain deserts. There are vast intermontane depressions with desert-steppe landscapes.

East Asia. East Asia is the neotectonically mobile outlying area of Eurasia, in which Mesozoic and alpine folded structures play a considerable role. Monsoon types of climates and landscapes not impoverished by ancient glaciation predominate. Hurricanes of tropical origin (typhoons) are characteristic.

CONTINENTAL EAST ASIA. Continental East Asia consists of aggradation plains (the Amur Region, Sung Liao, and the North China Plain), low mountains and midlands (SikhoteAlin’, the Khingan-Bureia and Manchurian-Korean mountains, and Nan Ling), regenerated and rejuvenated by sections of ancient platforms and of Paleozoic and Mesozoic folded structures. The organic world is rich in relict species (Manchurian flora in the north and evergreen Chinese-Japanese flora and predominantly Manchurian-Chinese fauna in the south). There are monsoon-forest, forest-steppe, and mountain-forest landscapes, ranging from moderately cold in the north to subtropical and subequatorial in the south. Forest-steppe “Amur prairies” are found in the northern plains areas.

KAMCHATKA AND EAST ASIAN ISLANDS (KURIL, JAPANESE, AND RYUKYU). Kamchatka and the East Asian islands are neotectonically sharply mobile mountainous island arcs with behavior characteristic of a modern geosyncline area (earthquakes, active vulcanism). There is a humidifying influence of both summer and winter monsoons. Recent mountain glaciation is found in the volcanoes of Kamchatka. The topography passes from tundra-forests and mountainous taigas in the north through mountainous broad-leaved forests of the temperate zone to mountainous subtropical and subequatorial forests in the south.

Southern Asia. Notwithstanding the considerable inhomogeneity of tectonic structures and neotectonic behavior, the region of southern Asia is united by a predominance of subequatorial and equatorial types of landscapes and the prevalence of the monsoon climate; tropical hurricanes are characteristic of the area. The rich organic world is extremely old and was not depleted during glacial periods (there is Palaeotropical, predominantly Malayan fauna; in the west, Indo-African flora and Indo-Malayan fauna).

AUSTRALO-ASIATIC ARCHIPELAGOES, TAIWAN, AND SOUTHERN MALACCA PENINSULA. The region of the Australo-Asiatic archipelagoes (Malayan, Philippine, and Moluccan), the island of Taiwan, and the southern part of the Malacca Peninsula is characterized by neotectonically sharply mobile mountainous island arcs with alpine folded structure and sections of more ancient structures in a modern geosynclinal area with active vulcanism. Moist equatorial forests and mountainous gileas predominate. Monsoon forests and savannas are found in subequatorial zones.

INDOCHINA. The region of Indochina consists of rejuvenated and regenerated midlands and lowlands with Mesozoic folded structure and of aggradation plains in neotectonic depressions. Subequatorial and savanna forests, including mountainous, predominate.

HINDUSTAN, INDO-GANGETIC PLAIN, AND SRI LANKA. Hindustan, the Indo-Gangetic Plain, and Sri Lanka is an area of socle plains and plateaus on moderately mobile sections of an ancient platform. There are considerable sheets of trap-rock. Outlying block lowlands and midlands (the Eastern and Western Ghats, and the Sri Lanka highlands) are found. In northern Hindustan there is an intensely sagging aggradation piedmont plain. Subequatorial forests and savannas predominate (in the northwest, tropical semideserts and deserts).

HIMALAYAS. The Himalayas are a folded structure, sharply uplifted by neotectonic movements. Intense ancient and recent glaciation is found in the high mountains (elevations up to 8,848 m). Mountainous desert landscapes predominate in the north; in the south there is a meadow-forest spectrum of altitudinal zones, from steppes in the piedmont west of the Himalayas and damp tropical jungles near the foothills of the Eastern Himalayas to the glacionival zone. There is a preponderance of mountain forests and meadows.

European Mediterranean region, Asiatic highland area, and the Caucasus. The European Mediterranean region, the Asiatic highland area, and the Caucasus are highly mobile links of the alpine and Himalayan fold belt, with sharply differentiated elevations and depressions. There is a predominance of mountainous topography and subtropical landscapes, which are insignificantly depleted by ancient glaciation.

ASIATIC HIGHLAND AREA. The Asiatic highland area and the Greater Caucasus combine outlying alpine folded-block uplands and midlands with intermontane and piedmont plains, internal tablelands, volcanic cones, and plateaus. There are continental variations of the Mediterranean climate, with a spring precipitation maximum in the highlands. Mountain-forest landscapes are found on the moist coastal and windward slopes (on inner slopes of outlying mountains, mountainous steppe landscapes; and on plateaus, subtropical semideserts and deserts). There are meadow-forest-steppe and desert-steppe types of altitudinal zones.

EUROPEAN MEDITERRANEAN REGION. The European Mediterranean region is a part of the alpine geosynclinal (fold) region that was sharply shattered by differentiated up-lifts and settlings; it consists of a complex combination of young and old folded structures. There is deep mutual penetration of sea and land, with a limited distribution of piedmont plains, as well as active vulcanism. Mediterranean types of climate (dry summer, damp winter) and landscapes predominate. Hard-leaved shrub formations, in particular, are widespread. A meadow-forest spectrum of altitudinal zones is also found.

Southwest Asia. Southwest Asia is an ancient platform, with a prevalence of socle plains and outlying block mountains. Lava sheets are widespread. There are desert types of climate and landscapes. Considerable similarity (in terms of topography, climate, and landscape as a whole) to the natural conditions of northern and eastern Africa is noted.

SYRIAN AND ARABIAN PLATEAUS AND MESOPOTAMIA. The Syrian and Arabian plateaus and Mesopotamia are bedded and socle plains and lava plateaus. The Mesopotamian depression consists of sloped and flat alluvial plains in an area of continuing sagging of the foundation.

OUTLYING SOUTH ARABIAN MOUNTAINS. Outlying mountains in southern Arabia (Oman, Hadhramaut, Yemen, and Hejaz) are block midlands with a desert-steppe spectrum of altitudinal zones. There is Palaeotropical (Indo-African) flora and fauna of the Ethiopian zopgeographic region.

In addition to the scheme for division into physical and geographic regions introduced above, other schemes exist for the division of Eurasia or its individual parts (see, for example, Fiziko-geograficheskii atlas mira, 1964, and Fizikogeograficheskoe raionirovanie SSSR, 1968).

REFERENCES

Zarubezhnaia Aziia: Fizicheskaia geografiia. Moscow, 1956.
Vlasova, T. V. Fizicheskaia geografiia chastei sveta, 2nd ed. Moscow, 1966.
Gvozdetskii, N. A., and N. I. Mikhailov. Fizicheskaia geografiia SSSR: Aziatskaia chast’’. Moscow, 1970.
Gourou, P. Aziia. Moscow, 1956. (Translated from French.)
Dobrynin, B. F. Fizicheskaia geografiia Zapadnoi Evropy. Moscow, 1948.
Efremov, lu. K. “Delenie territorii SSSR na fiziko-geograficheskie strany na fone prirodnogo raionirovaniia Evrazii.” Zhizn’ Zemli, 1961, no. 1.
Markov, K. K., G. I. Lazukov, and V. A. Nikolaev. Chetvertichnyi period, vols. 1–2. Moscow, 1965.
Mil’kov, F. N., and N. A. Gvozdetskii. Fizicheskaia geografiia SSSR: Obshchii obzor. Evropeiskaia chast’ SSSR. Kavkaz. Moscow, 1969.
Sinitsyn, V. M. Paleografiia Azii. Moscow-Leningrad, 1962.
Tektonika Evrazii: Ob” iasnitel naia zapiska. Edited by A. L. lanshin. Moscow, 1966.
Fiziko-geograficheskii atlas mira. Moscow, 1964.
Fiziko-geograficheskoe raionirovanie SSSR. Moscow, 1968.
Fizicheskaia geografiia SSSR, 2nd ed. Moscow, 1966.
Fizicheskaia geografiia chastei sveta. Moscow, 1963.

IU. K. EFREMOV

Eurasia

the continents of Europe and Asia considered as a whole

Eurasia

Eur·a·sia

Eurasia

Eur•a•sia

Eurasia

Eurasia

Eurasia

REFERENCES

Eurasia

Eurasia

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noun the land mass formed by the continents of Europe and Asia

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