World Terrain (3D)

Author: Chen Yu
Publisher:
Publish Date: 2003-08-01
Features: Most of the Earth's surface is covered by oceans, with land occupying only a small portion. The total surface area of the Earth is approximately 51 million square kilometers, of which the ocean area is about 36 million square kilometers, accounting for 70.8% of the total surface area. The land area is about 14.9 million square kilometers, accounting for 29.2% of the total surface area. In other words, seven-tenths of the Earth's surface is ocean, and three-tenths is land. The landmasses on the Earth's surface are divided into many land blocks of varying sizes by the oceans. The large land areas surrounded by oceans are called continents, while the smaller land areas are called islands. Continents and their nearby islands together are referred to as continents. This way, the landmasses on the Earth are divided into six continents: the Eurasian continent, the African continent, the North American continent, the South American continent, the Antarctic continent, and the Australian continent. The oceans on the Earth's surface are interconnected, forming a unified world ocean. Based on the distribution of land and sea, the world's oceans can be divided into four parts: the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic Ocean. There are no natural boundaries between them, and they are usually divided by underwater ridges or certain meridians. The elevation of the Earth's surface varies greatly, with diverse landforms. Landforms are typically divided into plains, plateaus, basins, mountains, and hills. They are distributed in varying scales across the continents, collectively forming a rugged and uneven surface. The mountains on land have two massive mountain ranges: one is the Pacific Ring of Fire, which extends north-south along both sides of the Pacific Ocean, including the Cordilleran-Andean mountain system running through the western part of the North American continent, as well as the mountains along the Pacific coast of Asia and Australia and the East Asian island arcs. The other is roughly east-west, stretching across the central and southern parts of the Eurasian continent and the northern edge of the African continent. Its western part includes the Alps and the Atlas Mountains, which, after entering Asia, merge with the mountains on both sides of the Turkish Plateau, the Hindu Kush Mountains, the Karakoram Mountains, and the Himalayas. It then continues through the western mountains of the Indochinese Peninsula and extends to the southern island arcs of the Sunda Islands, connecting with the Pacific Ring of Fire. These two mountain ranges are products of the Alpine orogeny, with high and majestic terrain, abundant volcanoes and earthquakes. The plains on land are generally distributed in the middle of the continents, with mountains surrounding both sides, forming three longitudinal terrain belts. This is most prominent in the North American continent, and Australia also has a similar terrain structure. However, on the Eurasian continent, plains are primarily found north of the east-west mountain ranges, such as the Central European Plain, the Eastern European Plain, the West Siberian Plain, and the Turan Plain. To the south, plains are mostly formed by river deposits and are distributed between plateaus, such as the Mesopotamian Plain, the Indo-Gangetic Plain, as well as the Northeast Plain, the North China Plain, and the Middle-Lower Yangtze Plain in China. The land is also widely covered with large uplifted plateaus, which are generally centered around Precambrian ancient continental blocks and have relatively stable crusts with little surface relief. Examples include the plateaus of the African continent, the Central Siberian Plateau, the Mongolian Plateau, the Arabian Plateau, and the Deccan Plateau on the Eurasian continent, the Brazilian Plateau on the South American continent, and the northern plateau of the Australian continent. The Antarctic continent, similar to the African continent, is also dominated by plateaus but is covered with thick ice layers. Additionally, there are plateaus embedded between young mountain ranges on land, with relatively active tectonic activity, high elevations, and significant surface relief, such as the Tibetan Plateau, the Anatolian Plateau, the Iranian Plateau, and some intermontane plateaus distributed within the Cordilleran-Andean mountain system. Small landmasses scattered in the oceans, rivers, or lakes are called islands. The total area of the world's islands accounts for about 7% of the total land area, with the largest island being Greenland in northeastern North America. Many islands that are very close to each other are collectively called archipelagos, such as the Malay (South Sea) Archipelago and the West Indies. A peninsula is a landmass that extends into the ocean or a lake, surrounded by water on three sides and connected to the mainland on one side, such as the Arabian Peninsula and the Indochinese Peninsula.