Asia Essay Research Paper AsiaAsia is the — страница 2

  • Просмотров 534
  • Скачиваний 9
  • Размер файла 24

across the middle of China, separating North China from South China, as the Qin Ling (Tsinling). The third and most southerly of the mountain belts radiating eastward from the Pamirs turns southeastward to form the Karakoram Range and the Himalayas and then abruptly southward at the eastern end of the Tibetan Plateau, where it splits into lesser ranges that continue southward as the Arakan Yoma in Burma, the mountainous rib of the Malay Peninsula, and the Annam Mountains (Annamitic Cordillera) in Vietnam. Numerous plateaus and structural basins are located within or along the margins of these mountain ranges. The highest is the Tibetan Plateau, which has an average elevation of over13,000 ft and is bordered by some of the world’s highest mountains, including the Himalayas on

the south, the Karakoram on the west, and the Kunlun Mountains on the north. This entire complex of high mountains and plateaus is often referred to as the “roof of the world.” To the north of Tibet are three important Chinese basins: the Qaidam (Tsaidam) Basin, the Tarim Basin , and the Junggar (Dzungarian) Basin. Also important to China are the Sichuan (Szechwan, or Red) Basin, located in the western province of Sichuan; the Gobi Plateau, a vast, semidesert upland located in Mongolia and China’s Inner Mongolian Autonomous Region and the Loess Plateau, located south of the Gobi, which is covered with an immense thickness of windblown loess deposits derived from the Gobi. Other plateaus in Asia are the Anatolian Plateau, in Turkey; the Arabian Plateau, mainly in Saudi

Arabia; the Deccan Plateau, in peninsular India; and the Vitim and Aldan plateaus, in Russia. Numerous islands, arranged in a series of arcs, fringe the Southeast Asian and Pacific coasts of the continent. The islands of the Southeast Asian archipelago pick up the main trend lines of Burma’s Arakan Yoma and continue them through the Andaman and Nicobar islands of India and the islands of Sumatra, Java, and Bali in the Indonesian archipelago. Near Bali the main trend of the mountainous belt splits into two segments. One segment continues eastward through the islands of Timor, the Moluccas, and New Guinea and eventually forms the mountains of New Zealand; the other segment turns northeastward and passes in a series of arcs through Borneo, the Philippine archipelago, Taiwan, the

Ryukyu Islands, Japan, and Sakhalin and the Kuril Islands before touching the mainland in the Kamchatka Peninsula (Russia). These island arcs are seismically active, and earthquakes and volcanic eruptions frequently occur. Asia’s most extensive lowlands are located in former Soviet Asia. They are the Western Siberian Plain, a vast, subarctic forested region located east of the Urals, and the Kirghiz Steppe, a semiarid plain located mainly in Kazakhstan. Other important lowlands are mainly in the alluvial valleys and deltas developed by rivers flowing to the south and east. The largest of the alluvial valleys is the Indo-Gangetic Plain, located in the Indian subcontinent between the Himalayas and the Deccan Plateau. Occupying parts of Pakistan, India, and Bangladesh, it is

drained by the Indus, Ganges, and Brahmaputra rivers; river water is diverted extensively across the plain for irrigation, and the region is one of the world’s most intensively cultivated and most densely populated places. Other Asian lowlands are the North China Plain, its soils enriched for centuries by loess sediments spread over the valley and deltas of the Huang He (Hwang Ho, or Yellow River); the alluvial valleys and deltas of the Yangtze (China), Irrawaddy (Burma), and Mekong (Cambodia) rivers; and the Fertile Crescent of the Tigris and Euphrates rivers in Iraq. Geology Five Asian “shield” areas (geologically stable areas of ancient crystalline rock) are usually recognized. They are the Arabian and Indian shields in the south and the Tarim Basin (Seridian massif),

Northern China (the Chinese massif), and the Siberian (Angara) Shield. Great thicknesses of sediments accumulated between these blocks of stable rocks and were subsequently folded and uplifted in periods of mountain building (orogenies). Asia has had a complex orogenic (mountain-building) history. The Caldonian Orogeny occurred in the Silurian and Devonian periods and is recorded in Asia by the Sayan and other mountains of eastern Siberia. The Hercynian Orogeny occurred in the Late Carboniferous (Pennsylvanian) and Permian periods and created several mountain ranges–the Urals, Tian Shan, Kunlun, and Qin Ling (Tsingling). According to plate-tectonics theory, by the close of the Permian Period, Asia, together with the ancestral cores of all the other continents, formed the